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Sample records for spodumene parametros cineticos

  1. Luminescence study of spodumene

    International Nuclear Information System (INIS)

    Isotani, S.; Fujii, A.T.; Antonini, R.; Pontuschka, W.M.; Rabani, S.R.; Furtado, W.W.

    1990-02-01

    A comparative study is made of the luminescence of five kinds of spodumene from Minas Gerais, Brazil, studied previously by optical absorption spectroscopy. Natural gemstones are used which, in the course of the experiments, were irradiated with X-rays. (L.C.) [pt

  2. Fluorescence and optical absorption in spodumene

    International Nuclear Information System (INIS)

    Antonini, R.

    1987-01-01

    This work studied the mechanism of the isothermal decay's kinetic of the 15.600 cm-1 optical absorption band (A.O.) of irradiated spodumene, and the phosphorescence of irradiated spodumene in low temperatures. The kinetic mechanisms applying the bimolecular model to liberation, capture and recombination reactions are analysed. The coupled differential equations, resultants of this model, numerically using the Runge-Kutta method is solved, and a computer programs that allowed determine the kinetics parameters by try and error methods is developped. This work showed that the electrons are untrapped according to Arrhernios kinetic and that the parameters of the trap and recombination are proportional to a factor (√T - √T o ), where T o is the cutting temperature, bfore which the reactions do not occur. (author) [pt

  3. Time measurements for thermalequilibrium in spodumene crystals

    International Nuclear Information System (INIS)

    Fujii, A.T.; Isotani, S.

    1982-01-01

    Experiments for measurement of time taken to reach thermal equilibrium in Spodumene crystals - 2mm to 5,4mm thick - in the temperature range 100 0 to 250 0 C are described. The measurements indicate a linear relationship between time and thickenes for heating as well as for cooling. Difference in thermal equilibrium time for heating and for cooling is about of 20 seconds. (author) [pt

  4. Crystallization and properties of a spodumene-willemite glass ceramic

    International Nuclear Information System (INIS)

    Hu, A.M.; Li, M.; Dali, D.L. Mao; Liang, K.M.

    2005-01-01

    Spodumene-willemite glass ceramics were produced by replacement of Al 2 O 3 in lithium aluminium silicate by ZnO. With replacement of Al 2 O 3 by ZnO, the batch melting temperature, glass transition temperature (T g ) and crystallization temperature (T p ) all decreased. The main crystalline phases precipitated were eucriptite, β-spodumene and willemite (Zn 2 SiO 4 ). All compositions of glass ceramics showed bulk crystallization. As ZnO content increased, the grain sizes and thermal expansion coefficients increased, while the flexural strength and fracture toughness of the glass-ceramics increased first, and then decreased. The mechanical properties were correlated with crystallization and morphology of glass ceramics

  5. Radiation detection using the color changes of lilac spodumene

    International Nuclear Information System (INIS)

    Oliveira, Raquel A.P.; Mello, Ana Carolina S.; Lima, Hestia R.B.R.; Campos, Simara Santos; Souza, Suzana O.

    2009-01-01

    The use of radiation in industrial processes currently offers several advantages in the field of sterilization of medical and pharmaceuticals products, the preservation of food, and a variety of other products widely used in modern society. A dosimetry of confidence is a key parameter for the quality assurance of radiation processing and the irradiated products. This work investigates dosimetric properties in natural spodumene, LiAlSi 2 O 6 , called kunzite, from Minas Gerais State, Brazil. After X irradiation on the samples in powder form was detected a change in color of the crystal where the dose received. This makes a possible viability of this material is applied in research on development of radiation detectors using the change in color of purple spodumene. (author)

  6. Luminescence spectra of lead tungstate, spodumene and topaz crystals

    International Nuclear Information System (INIS)

    Ramachandran, Vasuki

    2002-01-01

    A detailed set of thermoluminescence, cathodoluminescence and radioluminescence (TL, CLTL and RLTL) data of lead tungstate, Spodumene and Topaz have been reported for the first time over a wide temperature range from 25 to 500K. Lead tungstate (PbWO 4 ), a widely known scintillating material, gives TL glow peaks which are related to complex defect centres. Doping of this crystal with trivalent rare earth ions (La 3+ , Y 3+ ) reduces the slow component of the emission thereby making it more suitable for its applications. The pentavalent dopants on the other hand, enhance the green emission and quench the blue emission at temperatures 100K. The origin and the irradiation temperature definitely have an effect on the spectrum. No strong relationship could be derived from the dose dependence data. Two less studied minerals, Spodumene and Topaz have also been investigated with the luminescence techniques. The glow peak near 250degC is thought to have originated from Mn 2+ centres. As there are no ESR data available, the assignment of defect centres is rather difficult. Cr + acts as the quencher in green spodumene. Topaz had the same treatment as the other two sets of samples and the defect centre characterisation looks complex as each coloured sample gave different patterns of glow peaks. Cathodoluminescence whilst heating (CLTL) of all these samples showed some unusual features in the form of a luminescence intensity step which is believed to have originated from the presence of ice. Water, in nanoparticle size quantities, is present as a contaminant in the lattice and undergoes a phase transition at 170K from hexagonal to cubic structures. This phase change influences the luminescence efficiency of the host material and is reflected in the spectrum as a discontinuity in intensity. (author)

  7. In situ synchrotron XRD analysis of the kinetics of spodumene phase transitions.

    Science.gov (United States)

    L Moore, Radhika; Mann, Jason P; Montoya, Alejandro; Haynes, Brian S

    2018-04-25

    The phase transition by thermal activation of natural α-spodumene was followed by in situ synchrotron XRD in the temperature range 896 to 940 °C. We observed both β- and γ-spodumene as primary products in approximately equal proportions. The rate of the α-spodumene inversion is first order and highly sensitive to temperature (apparent activation energy ∼800 kJ mol-1). The γ-spodumene product is itself metastable, forming β-spodumene, with the total product mass fraction ratio fγ/fβ decreasing as the conversion of α-spodumene continues. We found the relationship between the product yields and the degree of conversion of α-spodumene to be the same at all temperatures in the range studied. A model incorporating first order kinetics of the α- and γ-phase inversions with invariant rate constant ratio describes the results accurately. Theoretical phonon analysis of the three phases indicates that the γ phase contains crystallographic instabilities, whilst the α and β phases do not.

  8. Optical absorption study of radiation and thermal effects in Brazilian samples of spodumene

    International Nuclear Information System (INIS)

    Isotani, S.; Fujii, A.T.; Antonini, R.; Furtado, W.

    1988-03-01

    A detailed analysis of the optical absorption spectra of five varieties of Brazilian spodumene is presented. The samples were submitted to heat treatments and irradiated with gamma rays, x radiation, electrons and ultraviolet light. (M.C.K.) [pt

  9. Comparative study of five varieties of spodumene through optical absorption

    International Nuclear Information System (INIS)

    Fujii, A.T.; Isotani, S.

    1983-11-01

    A comparative study of five varieties of spodumene crystals from Brazil through optical absorption spectroscopy, classified according to the colours lylac, colourless I, colourless II, yellow and green is reported. This series shows a consistent increase of the [Fe]/[Mn] ratio. The principal bands in the yellow sample are at 7,000 and 9,000 cm -1 , and in the green sample besides these bands a band at 16,000 cm -1 is observed. In lylac, colourless I and colourless II samples, the principal bands are at 18,000 cm -1 and when irradiated two new bands appears at 15,700 cm -1 (E perpendicular to c) and 11,000 cm -1 (K perpendicular to c). It is suggested that in green and yellow samples the bands are due to Fe 2+ (at 7,000 cm -1 and 9,000 cm -1 ) and due to Fe 2+ - Fe 3+ charge transfer (at 16,000 cm -1 ). In lylac and colourless I samples the model for Mn 3+ at two different sites is applied. The colourless II corresponds to the case in which Mn 3+ is at one site alone, being prohibited from occupying the second site due to higher Fe concentration. (Author) [pt

  10. Influence of the amount containing spodumene or albite on the sintering of a triaxial ceramic

    International Nuclear Information System (INIS)

    Oliveira, Camila Felippe de; Strecker, Kurt

    2012-01-01

    In this study, we investigated the properties of porcelain stoneware, made with albite or spodumene. The amount of the feldspar in the compositions ranged from 15 to 30% by weight. Specimens were pressed and sintered at 1000, 1100, 1200 and 1280 °C with an isotherm of 1 hour at the maximum temperature. The samples were characterized by analysis of the fracture surface using scanning electron microscopy and the vitrification curves, showing both the linear shrinkage and porosity in relation to the sintering temperature. The best results were obtained for samples containing 30% spodumene sintered at 1280 °C, with a linear shrinkage of 9.97% and porosity of 13.28%, while the corresponding results of samples containing 30% albite were 10.13% and 12.17%, respectively. It is concluded that the use of spodumene in the production of porcelain stoneware is viable, resulting in comparable properties. (author)

  11. Preliminary evaluation of beta-spodumene as a fusion reactor structural material

    International Nuclear Information System (INIS)

    Kelsey, P.V. Jr.; Schmunk, R.E.; Henslee, S.P.

    1982-01-01

    Beta-spodumene was investigated as a candidate material for use in fusion reactor environments. Properties which support the use of beta-spodumene include good thermal shock resistance, a very low coefficient of thermal expansion, a low-Z composition which would result in minimum impact on the plasma, and flexibility in fabrication processes. Specimens were irradiated in the Advanced Test Reactor (ATR) to a fluence of 5.3 x 10 22 n/m 2 , E > MeV, and 4.9 x 10 23 n/m 2 thermal fluence in order to obtain a preliminary evaluation of the impact of irradiation on the material. Preliminary data indicate that the mechanical properties of beta-spodumene are little affected by irradiation. Gas production and release have also been investigated. (orig.)

  12. Spectrophotometric study of bio-sorption of uranium on glass grade spodumene shell powder

    International Nuclear Information System (INIS)

    Parakudyil, A.S.; Pillai, A.K.; Reddy, A.V.R.; Singal, R.K.; Sharma, P.K.; Michael, K.M.

    2012-01-01

    Separation of uranium found in iron ore leachates was done by extraction chromatography using glass grade spodumene shellpowder (GSS) in nitric acid medium and analyzed spectrophotometrically. The influences of metal ion concentration, pH and adsorption capacity of biomass were investigated. Biosorption is a potential method of separation of heavy and trace metals from waste water and effluents from various sources. The adsorption capacities of biomass were investigated by batch experiments and column experiments. In the present study, glass grade spodumene shell powder (GSS) in acidic medium is being used as a biosorbent

  13. Kinetic study on the chlorination of β-spodumene for lithium extraction with Cl2 gas

    International Nuclear Information System (INIS)

    Barbosa, L.I.; Valente, N.G.; González, J.A.

    2013-01-01

    Highlights: ► β-Spodumene was chlorinated to extract lithium with pure chlorine. ► The kinetics of the chlorination was studied in the range of 1000–1100 °C. ► Cl 2 flow rate, sample mass, and Cl 2 partial pressure were the operating variables. ► Experimental data were best fitted by the sequential nucleation and growth model. - Abstract: In this paper, the kinetics chlorination of β-spodumene for the extraction of lithium has been studied using gaseous chlorine as chlorinating agent. The effect of chlorine flow rate, temperature, mass of the sample, and partial pressure of Cl 2 was investigated. The study of the effect of chlorine flow rate indicated that the chlorination of β-spodumene may be carried out in the presence of active chlorinating species The chlorine partial pressure was found to have an appreciable effect on the system reactivity. The temperature was found to be the most important variable affecting the reaction rate. The β-spodumene chlorination process by Cl 2 was characterized by an apparent activation energy of about 359 kJ/mol in the range from 1000 to 1100 °C. Reaction was of non-catalytic gas–solid nature and experimental data fitted the sequential nucleation and growth model

  14. Optical properties of alpha spodumene: Orientation of its principal optical axes

    Energy Technology Data Exchange (ETDEWEB)

    Souza, S O; Lima, A F [Universidade Federal de Sergipe, Departamento de Fisica, PO Box 353, 49100-000 Sao Cristovao - SE (Brazil); Lalic, M V, E-mail: mlalic@fisica.ufs.b

    2009-05-01

    We studied the orientation of the three orthogonal principal optical axes of the alpha spodumene crystal. This orientation is determined relative to the crystallographic axes, and expressed as function of the incident radiation wavelength in ultraviolent region. The calculations were performed by density functional theory based, full potential augmented plane wave method.

  15. Thermoluminescent kinetic parameters of the perovskite, KMgF{sub 3}, activated with lanthanum; Parametros cineticos termoluminiscentes de la perovskita, KMgF{sub 3}, activada con lantano

    Energy Technology Data Exchange (ETDEWEB)

    Sepulveda M, F. [ESFM-IPN, 07738 Mexico D.F. (Mexico); Azorin N, J.; Rivera M, T. [UAM-I, 09340 Mexico D.F. (Mexico); Furetta, C.; Sanipoli, C. [Physics Department, Universita di Roma ' ' La Sapienza' ' , Piazzale A. Moro 2, 00185 Roma (Italy)

    2004-07-01

    The thermoluminescent curves induced by the beta radiation in the perovskite KMgF{sub 3} were investigated activated with lanthanum. The classic methods were used to determine the kinetic parameters (the kinetic order b, the activation energy E and the frequency of escape intent s) associated with the peaks of the thermoluminescent curve (Tl) in the KMgF{sub 3} activated with lanthanum after the irradiation with beta rays. The method is based on the position of the thermoluminescent peaks, obtained of the temperature change of the peak in the maximum emission caused by the change in the heating rapidity to which the samples were measured. In this work, the samples in form of pellets were re cooked previously at 400 C during one hour before irradiating them with beta particles. The Tl measures were made with a Tl reader system using three different heating rapidities and storing the glow curves. To calculate the depth of the E traps and the frequency factor s, the parameters of the glow curve were determined experimentally of the shame of the glow curve by means of the mensuration of the shame of the maximum temperature of the peak, T{sub M} like a function of the heating rapidity. The results indicate that the values of the kinetic parameters are very near among if when they are obtained indistinctly of anyone of the different methods. (Author)

  16. Investigation of Enhanced Leaching of Lithium from α-Spodumene Using Hydrofluoric and Sulfuric Acid

    Directory of Open Access Journals (Sweden)

    Hui Guo

    2017-10-01

    Full Text Available An effective method using hydrofluoric and sulfuric acid was proposed to enhance the leaching of lithium from α-spodumene, without calcination that is subjected to 1000 °C for phase transformation. The thermodynamic feasibility of the reactions was firstly verified. Dissolution conditions were tested to maximize the leaching efficiency of lithium and with efficient utilization of hydrofluoric acid (HF served as evaluation criteria. The results showed that 96% of lithium could be transferred into lixivium with an ore/HF/H2SO4 ratio of 1:3:2 (g/mL/mL, at 100 °C for 3 h. Due to the fact that HF molecules were the main reaction form, the dissolution behaviors were theoretically represented and investigated by dissolution in HF/H2SO4. When combined with chemical elements analyses and characterizations, the results of the dissolution behaviors revealed that α-spodumene and albite were preferentially dissolved over quartz. Insoluble fluoroaluminates, such as AlF3, cryolite (Na3AlF6 and cryolithionite (Na3Li3Al2F12, were generated and might be further partially dissolved by H2SO4. Fluorosilicates, such as K2SiF6, Na2SiF6, or KNaSiF6, were also generated as a part of the insoluble residues. This work provides fundamental insight into the role of HF/H2SO4 played in the dissolution of α-spodumene, and sheds light on a novel and promising process to efficiently extract lithium.

  17. Determining Age and Origin of Spodumene-Bearing Pegmatites in Southeastern Ireland

    Science.gov (United States)

    Brown, A. A.; Barros, R.; Menuge, J. F.

    2017-12-01

    Exploration prospecting around Caldonian Leinster Granite has revealed pegmatite intrusions containing spodumene, a lithium ore, on the eastern margin of the Tullow Lowlands Pluton. Drill cores of these pegmatites have been extracted and studied due to increasing economic interest. Ages between 430 and 400 Ma for spodumene pegmatites have been previously determined using the in situ Rb-Sr isochron method [1]. Here we use the Sm-Nd isochron method to see if the less-mobile nature of REEs during contact metamorphism and deformation impacts ages. Suitable samples containing garnet and feldspar from spodumene and barren pegmatites were studied using regular microscopy and SEM; minerals were then isolated manually. After mineral dissolution and elemental separation via ion exchange columns, a Neptune MS measured Sm and Nd isotope ratios. Blank corrections were applied. Both types of pegmatites were used to calculate an isochron using Isoplot 3.7 [2] which yielded an initial 143Nd/144Nd ratio of 0.51190±0.00009, and an age of 414±52 Ma. Ages and ɛNd, relating to the initial Nd ratio, were compared with previous whole rock data of Leinster Granite [3] and Rb-Sr multimineral data [1]. Comparable ages from both methods likely represent crystallization age. At the minimum possible age considering uncertainty, the origins of pegmatites and granitic rocks are indistinguishable, but at the maximum age, pegmatites show lower ɛNd values suggesting heterogeneous sources. All representative data points held negative ɛNd values signifying crustal assimilation. The Sm-Nd method was found suitable for age/ source investigation; however, Leinster pegmatite garnet is particularly depleted in Nd (Microsoft Excel. Berkeley Geochronology Center Special Publication, 4 [3] Mohr, Peter (1991): "Cryptic Sr and Nd isotopic variation across the Leinster Granite, Southeast Ireland" Geology Magazine, Vol 128, 3, 251-256

  18. Extraction of lithium from β-spodumene using chlorination roasting with calcium chloride

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Lucía I., E-mail: lbarbosa@unsl.edu.ar [Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco 17, CP 5700 San Luis (Argentina); González, Jorge A. [Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco 17, CP 5700 San Luis (Argentina); Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Padre Jorge Contreras 1300, Parque General San Martín, CP M5502JMA Mendoza (Argentina); Ruiz, María del Carmen [Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco 17, CP 5700 San Luis (Argentina)

    2015-04-10

    Highlights: • β-Spodumene was roasted with calcium chloride to extract lithium. • The optimal conditions of the chlorination process are 900 °C and 120 min. • The products of the reaction are lithium chloride, anorthite, and silica. - Abstract: Chlorination roasting was used to extract lithium as lithium chloride from β-spodumene. The roasting was carried out in a fixed bed reactor using calcium chloride as chlorinating agent. The mineral was mixed with CaCl{sub 2} on a molar ratio of 1:2. Reaction temperature and time were investigated. The reactants and roasted materials were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and atomic absorption spectrophotometry (AAS). The mineral starts to react with CaCl{sub 2} at around 700 °C. The optimal conditions of lithium extraction were found to be 900 °C and 120 min of chlorination roasting, under which it is attained a conversion degree of 90.2%. The characterization results indicate that the major phases present in the chlorinating roasting residue are CaAl{sub 2}Si{sub 2}O{sub 8}, SiO{sub 2}, and CaSiO{sub 3}.

  19. Study of the Extraction Kinetics of Lithium by Leaching β-Spodumene with Hydrofluoric Acid

    Directory of Open Access Journals (Sweden)

    Gustavo D. Rosales

    2016-09-01

    Full Text Available Parameters affecting the kinetics of the dissolution of β-spodumene with hydrofluoric acid have been investigated. The experimental tests were carried out in a closed vessel. The influence of several parameters, such as stirring speed, temperature, and reaction time were studied in order to deduce the kinetics of the dissolution reaction. The other parameters, particle size −45 μm; HF concentration 4% v/v, and the solid–liquid ratio 0.95% w/v were kept constant. The results indicate that the stirring speed does not have an important effect on the dissolution of the mineral above 330 rpm. The extent of the leaching of β-spodumene increases with temperature and reaction time augmentations. Scanning electron microscope (SEM analyses of some residues in which the conversion was lower than 30% indicated a selective attack on certain zones of the particle. The treatment of the experimental data was carried out using the Modelado software. The model that best represents the dissolution of the mineral is the following: ln(1 − X = −b1 [ln(1 + b2t − b2t/(1 + b2t]. This model is based on “nucleation and growth of nuclei” theory, and describes the style of attack physically observed by SEM on the residues.

  20. Extraction of lithium from β-spodumene using chlorination roasting with calcium chloride

    International Nuclear Information System (INIS)

    Barbosa, Lucía I.; González, Jorge A.; Ruiz, María del Carmen

    2015-01-01

    Highlights: • β-Spodumene was roasted with calcium chloride to extract lithium. • The optimal conditions of the chlorination process are 900 °C and 120 min. • The products of the reaction are lithium chloride, anorthite, and silica. - Abstract: Chlorination roasting was used to extract lithium as lithium chloride from β-spodumene. The roasting was carried out in a fixed bed reactor using calcium chloride as chlorinating agent. The mineral was mixed with CaCl 2 on a molar ratio of 1:2. Reaction temperature and time were investigated. The reactants and roasted materials were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and atomic absorption spectrophotometry (AAS). The mineral starts to react with CaCl 2 at around 700 °C. The optimal conditions of lithium extraction were found to be 900 °C and 120 min of chlorination roasting, under which it is attained a conversion degree of 90.2%. The characterization results indicate that the major phases present in the chlorinating roasting residue are CaAl 2 Si 2 O 8 , SiO 2 , and CaSiO 3

  1. Preparation of. beta. -spodumene glass-ceramics from blast furnace slag. Koro slag wo genryo to shita. beta. -spodumene kei kesshoka glass no seizo

    Energy Technology Data Exchange (ETDEWEB)

    Wang, M. (National Kaoshing Institute Technology, Kaoshiung (Rep. of China)); Hon, M. (National Cheng Kung University, Tainan (Rep. of China))

    1990-07-01

    Li {sub 2} O-CaO-Al {sub 2} O {sub 3} -SiO {sub 2} (LCAS) glass-ceramics were prepared from blast furnace slag by quenching in water after heating at 1,450 {degree} C for 3 hours. Blast furnace slag (40.0wt%) containing CaO, MgO, Al {sub 2} O {sub 3} and SiO {sub 2} as major components was used as a raw material, and batch compositions were modified by mixing blast furnace slag with Al {sub 2} O {sub 3}, SiO {sub 2} and Li {sub 2} CO {sub 3}, and a nucleating agent TiO {sub 2}. The A specimen with TiO {sub 2} of 7.4wt% and B specimen with 4.6wt% were prepared, and the crystallization process of the glass was examined with X-ray diffraction, electron diffraction and so forth. As a result, a major crystalline phase was {beta} -spodumene (Li {sub 2} O-Al {sub 2} O {sub 3} -4SiO {sub 2}), and the average thermal expansion coefficients of A and B were 40.1 and 47.2 {times} 10 {sup {minus} 7} / {degree} C in the temperature range from 25 to 700 {degree} C, respectively. A small amount of titanite was also observed in A as a sub-phase. 14 refs., 5 figs., 3 tabs.

  2. Anisotropic surface physicochemical properties of spodumene and albite crystals: Implications for flotation separation

    Science.gov (United States)

    Xu, Longhua; Peng, Tiefeng; Tian, Jia; Lu, Zhongyuan; Hu, Yuehua; Sun, Wei

    2017-12-01

    Aluminosilicate minerals (e.g., spodumene, albite) have complex crystal structures and similar surface chemistries, but they have poor selectivity compared to traditional fatty acid collectors, making flotation separation difficult. Previous research has mainly considered the mineral crystal structure as a whole. In contrast, the surface characteristics at the atomic level and the effects of different crystal interfaces on the flotation behavior have rarely been investigated. This study focuses on investigating the surface anisotropy quantitatively, including the chemical bond characteristics, surface energies, and broken bond densities, using density functional theory and classical theoretical calculations. In addition, the anisotropy of the surface wettability and adsorption characteristics were examined using contact angle, zeta potential, and Fourier-transform infrared measurements. Finally, these surface anisotropies with different flotation behaviors were investigated and interpreted using molecular dynamics simulations, scanning electron microscopy, and X-ray photoelectron spectroscopy. This systematic research offers new ideas concerning the selective grinding and stage flotation of aluminosilicate minerals based on the crystal characteristics.

  3. Optical absorption and electron spin resonance in natural, irradiated and heated spodumene

    International Nuclear Information System (INIS)

    Ito, A.S.; Isotani, S.

    1983-09-01

    Heat treatment and X and γ-Rays irradiation of lylac and colorless natural spodumene, LiAlSi 2 O 6 , have been studied. Irradiation produces a color change, from lylac or colorless to green. Irradiated samples heated at 200 0 C turn lylac and bleach at 400 0 C. Optical absorption spectra were decomposed into gaussian line shape bands and it is observed that green and lylac centers are simultaneously created by irradiation. These centers are independent from each other. Optical absorption, EPR and X-Ray fluorescence results show the spectra of impurities, responsible by the presence of the created centers and indicated Mn participation in the process of centers creation and destruction. Decay Kinetics of green and lylac centers have been studied and it is observed that simple Kinetic models do not apply to these cases. An empirical fit allowed the calculation of activation energies of the lylac and green centers decays. Discussions about the present results led us to propose a new model where the green and lylac centers are due to Mn 3+ ions in two different Al 3+ sites, whose absorption are intensified by the interaction with an electron trapped in a neighbour oxygen. (Author) [pt

  4. Determination of the kinetic parameters of K{sub 2}Y F{sub 5}: Tb; Determinacion de los parametros cineticos de K{sub 2}Y F{sub 5}: Tb

    Energy Technology Data Exchange (ETDEWEB)

    Gallegos, A.A. [CICATA-IPN, Legaria 694, Col. Irrigacion, 11500 Mexico D.F. (Mexico); Khaidukov, N.M. [Kurnakov Institute of General and Inorganic Chemistry, Moscow (Russian Federation); Azorin, J. [UAM-I, 09340 Mexico D.F. (Mexico)

    2005-07-01

    In this work the K{sub 2}Y doped materials with percentages of 0.01 and 0.2 of F{sub 5} and, 0.8 and 0.99 of Tb{sup 3+} were studied to determine the kinetic parameters (activation energy and frequency factor) of TL peaks with the purpose of comparing those sensitive qualities of the materials at the doping with TR and their candidacy for tests of TL dosimetry (linearity of the response with the absorbed dose and the reproducibility of the measures of the dose). The samples were irradiated with a beta source of {sup 90} Sr/{sup 90} Y, to ambient temperature, giving its a dose of 236.6 mGy, later the kinetic parameters with different experimental procedures were determined: isothermal decay to ambient temperature and erased of peaks not desired to greater temperature than the ambient. The glow curves (TL curves) were obtained with an TL analyzer Harshaw 4000, with interface to CPU for the handling of the data of the curves, which were treated with the curve form method and the models of: Chen first approach and Chen modified, corrected Lushchik approach and Grossweiner approach, to calculate the kinetic parameters of the sample. (Author)

  5. Determination of kinetic parameters in Tl dosemeters of LiF: Mg, Cu, P + PTFE developed in the ININ; Determinacion de parametros cineticos en dosimetros Tl de LiF: Mg, Cu, P + PTFE desarrollados en el ININ

    Energy Technology Data Exchange (ETDEWEB)

    Basurto G, B.S

    2002-07-01

    The objective of this work, is the one of determining the kinetic parameters of the dosemeter of LiF: Mg, Cu, P + Ptfe; starting from the curves Tl obtained at being irradiated with alpha radiation ({alpha}), beta ({beta}) and gamma ({gamma}). As like to compare its sensitivity with each radiation type, considering the sensitivity of the TLD-100 as the unit. In the Chapter 1, the fundamental structure of the matter is described, making emphasis in the different radiation types, and their interaction with this. In the Chapter 2, the units are described but used in the dosimetry of the radiation. In the Chapter 3, the basic concepts of the phenomenon of Tl are described and those are explained characteristic of the deconvolution method to determine the kinetics of the one phenomenon. In the Chapter 4, the methodology is detailed that was used in the elaboration of this thesis work, describing the material Tl that were considered like reference, as well as the sources of ionizing radiation, with those that the dosemeters were irradiated and the equipment in the one that the curves Tl was obtained. Reference is made to the software used to carry out the deconvolution of the curves Tl that were obtained in the one experimental development. In the Chapter 5, the obtained results of this study are presented, showing the tables of homogenization of dosemeters and the reading of the same one; they are observed the curves Tl obtained to different radiation doses (alpha, beta and gamma), the intensity Tl in function of the dose. Also they are tabulated, the obtained results in the kinetic parameters of the three different study materials (TLD-100H, USA; TLD-100, USA and LiF: Mg, Cu, P + Ptfe developed in the l.N.l.N). They are analyzed shortly for each material Tl their sensitivity to the ionizing radiation as well as their kinetic parameters. The obtained results showed that the Tl dosemeters of LiF: Mg,Cu,P + Ptfe, they presented a bigger sensitivity that the TLD-100 when being irradiated with gamma radiation of {sup 60} Co, in air. While when being irradiated with the same type of radiation, but in phantom of water, their sensitivity was lightly smaller. To the being irradiated with beta radiation of {sup 90} Sr, the relative sensitivity diminished and it was considerably smaller when being irradiated with alpha radiation of {sup 244} Cm. (Author)

  6. Application of the exact distribution pj{sub k} in the determination of kinetic parameters in a reactor; Aplicacion de la distribucion exacta p{sub k} a la determinacion de parametros cineticos de un reactor

    Energy Technology Data Exchange (ETDEWEB)

    Alca Ruiz, F

    1982-07-01

    In this report one distribution of neutron counts obtained by a detector placed in a reactor is studied in order to be used in the determination of reactor kinetic parameters such as {beta}/{lambda} and reactivities. The parameters accuracy from this new method is compared with the Feynman and Mogilner method, based too in Reactor Neutron Noise Analysis. These three methods have been applied to JEN-2 reactor and the better accuracy and faster collection of experimental data give some interest to the new method which only requires a good footing code. (Author) 68 refs.

  7. Rocha com espodumênio como fundente para massas cerâmicas tradicionais Spodumene rock as a flux for traditional ceramic bodies

    Directory of Open Access Journals (Sweden)

    S. R. Bragança

    2010-07-01

    Full Text Available Investigou-se a atuação de uma rocha com espodumênio como fundente em massas cerâmicas, analisando-se sua reatividade com outras matérias-primas, como quartzo e caulim. Primeiramente, caracterizou-se petrograficamente o pegmatito de onde se extrai esse fundente. Posteriormente avaliou-se o comportamento de moabilidade, fundência e deformação piroplástica da rocha com espodumênio. Analisou-se então sua influência nas propriedades tecnológicas finais das peças, principalmente em relação à temperatura de queima, às fases e à microestrutura. Comparou-se a gresificação com outros fundentes comerciais como a albita e o feldspato. O espodumênio mostrou maior capacidade de reduzir a temperatura de gresificação das peças que os fundentes tradicionais, promovendo a densificação por fluxo viscoso.A spodumene rock was used as a flux in ceramic bodies, analyzing its reactivity to other raw materials such as quartz and kaolin. The petrology properties of the pegmatite (parent rock from which the flux is extracted was characterized. The grindability, fluxing strength and pyroplastic deformation of the spodumene rock were investigated. The influence on technological properties of the final pieces, mainly in relation to the firing temperature, phases formation and microstructure were also further analyzed. The firing behavior to other commercial flux such as albite and feldspar were then compared. The spodumene rock was considered an effective flux, capable of reducing the firing temperatures of the tested bodies by viscous flow.

  8. Boro e Vanadio: requisiti di potabilitá e valori di parametro

    Directory of Open Access Journals (Sweden)

    M. Ferrante

    2003-05-01

    Full Text Available

    Obiettivi: i minerali, che costituiscono circa il 4% del peso corporeo e svolgono numerose ed importanti funzioni biodinamiche, si possono suddividere in due gruppi: elementi principali ed elementi essenziali. Gli elementi essenziali necessitano in quantità minime, dal millesimo di milligrammo fino a qualche decina di milligrammi e per la bassissima concentrazione nei tessuti del corpo umano vengono chiamati anche oligoelementi o minerali in traccia. I minerali in traccia sono stati molto attenzionati dalle normative per le acque potabili essendo per i suddetti motivi importanti requisiti di potabilità. Con l’evoluzione della normativa alcuni oligoelementi che prima erano citati solo per memoria adesso devono rientrare in precisi valori di parametro. Tra questi il boro e il vanadio. In questa nota riportiamo la problematica relativa alla presenza di boro e vanadio nelle acque utilizzate per il consumo umano nella zona etnea.

    Metodi: le acque utilizzate nella zona etnea, in particolare quelle della provincia di Catania, sono state analizzate con spettrofometria in emissione (Inductively Coupled Plasma e con spettrofotometria per Assorbimento Atomico (A.A.con effetto Zeeman per il dosaggio del boro e del vanadio in esse contenuti.

    Risultati: il boro e il vanadio essendo elementi naturalmente presenti nei vari comparti ambientali sono stati ritrovati nelle acque potabili della zona etnea in concentrazioni estremamente variabili che talvolta superano i valori di parametro.

    Conclusioni: alla luce dei risultati ottenuti, non essendo ancora dimostrata la reale tossicità per assunzione di tali elementi attraverso il canale alimentare ed essendo molto difficile la loro eliminazione dalle acque, si propone un riesame delle concentrazioni massime ammissibili sulla base della percentuale di assorbimento gastro-enterico e dei relativi “tollerable intake” con

  9. Homogenization Experiments of Crystal-Rich Inclusions in Spodumene from Jiajika Lithium Deposit, China, under Elevated External Pressures in a Hydrothermal Diamond-Anvil Cell

    Directory of Open Access Journals (Sweden)

    Jiankang Li

    2017-01-01

    Full Text Available Extensive studies of the crystal-rich inclusions (CIs hosted in minerals in pegmatite have resulted in substantially different models for the formation mechanism of the pegmatite. In order to evaluate these previously proposed formation mechanisms, the total homogenization processes of CIs hosted in spodumene from the Jiajika pegmatite deposit in Sichuan, China, were observed in situ under external H2O pressures in a new type of hydrothermal diamond-anvil cell (HDAC. The CIs in a spodumene chip were loaded in the sample chamber of HDAC with water, such that the CIs were under preset external H2O pressures during heating to avoid possible decrepitation. Our in situ observations showed that the crystals within the CIs were dissolved in carbonic-rich aqueous fluid during heating and that cristobalite was usually the first mineral being dissolved, followed by zabuyelite and silicate minerals until their total dissolution at temperatures between 500 and 720°C. These observations indicated that the minerals within the CIs were daughter minerals crystallized from an entrapped carbonate- and silica-rich aqueous solution and therefore provided useful information for evaluating the formation models of granitic pegmatites.

  10. Computação evolutiva aplicada a resolução do problema da arvore geradora minima com parametros fuzzy

    OpenAIRE

    Tiago Agostinho de Almeida

    2006-01-01

    Resumo: Este trabalho propoe meta-heurýsticas baseadas em tecnicas da computaçao evolutiva, que visam encontrar um conjunto de arvores geradoras mýnimas para problemas de grafos, que possuem incertezas em relaçao as informaçoes associadas aos parametros. Resolver problemas dessa natureza e um processo NP-Completo, pois envolve um numero enorme de comparaçoes. A fim de contornar essa complexidade, este trabalho propoe um algoritmo genetico e um sistema imunologico artificial, capazes de explo...

  11. Parameter changes during gradual flooding of a PEM fuel cell through EIS studies; Cambio en parametros de una celda de combustible PEM durante inundacion gradual mediante estudios de EIS

    Energy Technology Data Exchange (ETDEWEB)

    Cano Castillo, Ulises; Cruz Manzo, Samuel; Arriaga Hurtado, Gerardo [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Ortiz, Alondra; Orozco, German [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica S.C. (CIDETEQ) (Mexico)

    2008-07-01

    The gradual flooding of a single PEM fuel cell was produced and Electrochemical Impedance Spectroscopy (EIS) measurements were realized in order to follow changes of the fuel cell impedance parameters. These changes were followed by using two equivalent circuit models: one simple model of the Randles type accounting for cathode and anode interfaces and a more complex model based on distributed elements, more suitable for porous electrodes in order to include protonic resistance of the catalyst layers. [Spanish] La inundacion gradual de una monocelda de combustible tipo PEM fue estudiada empleando espectroscopia de impedancia electroquimica (EIS), con el proposito de seguir cambios en los parametros de impedancia de la celda. Estos cambios fueron estudiados utilizando dos circuitos equivalentes: un modelo simple de tipo Randles, el cual considerara las interfaces del catodo y del anodo, y un modelo mas complejo basado en elementos distribuidos, el cual fuera adecuado para electrodos porosos, a fin de incluir la resistencia protonica de las capas catalizadoras.

  12. Discussion on the parameters and events of interest for the projections (Chapter 5 in 'A vision of year 2030 on the use of the renewable energies in Mexico'); Discusion de los parametros y eventos de interes para las proyecciones (Capitulo 5 en 'Una vision al 2030 de la utilizacion de las energias renovables en Mexico')

    Energy Technology Data Exchange (ETDEWEB)

    Mulas del Pozo, Pablo [Universidad Autonoma Metropolitana, Mexico, D.F. (Mexico)

    2005-08-15

    In this chapter it is described how it was decided to analyze the problems to 25 years. Considering that the Secretaria de Energia (SENER) through the Secretaria de Palaeocene y Desarrollo Tecnologico makes an annual exercise of the prospective to ten years for the electrical sector, the natural gas sector and the oil derivatives sector, with the last one publishing the 2004-2013 period, it was decided that the projections for year 2013 were taken as facts and that the exercise to develop a vision be limited to the 2014 - 2030 period. The assumptions used to make the numerical simulations with the LEAP system are detailed in Annex 10, with the information gathered by the approach group on the parameters to be used in this task, as well as in Annex 14, that contains the specific information used together with the results obtained in the period the 2004-2013 and in the second period of 2014-2030. [Spanish] En este capitulo se describe como se decidio analizar la problematica a 25 anos. Considerando que la Secretaria de Energia (SENER) a traves de la Subsecretaria de Planeacion y Desarrollo Tecnologico realiza un ejercicio anual de prospectiva a diez anos para el sector electrico, el sector de gas natural y el sector de petroliferos, siendo el ultimo publicado el 2004-2013, se decidio que las proyecciones al 2013 se tomaran como hechos y que el ejercicio para desarrollar una vision se concretara al periodo del 2014 al 2030. Los supuestos utilizados para realizar las simulaciones numericas con el sistema LEAP se detallan tanto en el anexo 10 con la informacion recabada del grupo de enfoque sobre los parametros a usarse en esta tarea, como en el anexo 14 que contiene la informacion especifica utilizada asi como los resultados obtenidos en los periodos 2004-2013 y el segundo periodo del 2014-2030.

  13. Discussion on the parameters and events of interest for the projections (Chapter 5 in 'A vision of year 2030 on the use of the renewable energies in Mexico'); Discusion de los parametros y eventos de interes para las proyecciones (Capitulo 5 en 'Una vision al 2030 de la utilizacion de las energias renovables en Mexico')

    Energy Technology Data Exchange (ETDEWEB)

    Mulas del Pozo, Pablo [Universidad Autonoma Metropolitana, Mexico, D.F. (Mexico)

    2005-08-15

    In this chapter it is described how it was decided to analyze the problems to 25 years. Considering that the Secretaria de Energia (SENER) through the Secretaria de Palaeocene y Desarrollo Tecnologico makes an annual exercise of the prospective to ten years for the electrical sector, the natural gas sector and the oil derivatives sector, with the last one publishing the 2004-2013 period, it was decided that the projections for year 2013 were taken as facts and that the exercise to develop a vision be limited to the 2014 - 2030 period. The assumptions used to make the numerical simulations with the LEAP system are detailed in Annex 10, with the information gathered by the approach group on the parameters to be used in this task, as well as in Annex 14, that contains the specific information used together with the results obtained in the period the 2004-2013 and in the second period of 2014-2030. [Spanish] En este capitulo se describe como se decidio analizar la problematica a 25 anos. Considerando que la Secretaria de Energia (SENER) a traves de la Subsecretaria de Planeacion y Desarrollo Tecnologico realiza un ejercicio anual de prospectiva a diez anos para el sector electrico, el sector de gas natural y el sector de petroliferos, siendo el ultimo publicado el 2004-2013, se decidio que las proyecciones al 2013 se tomaran como hechos y que el ejercicio para desarrollar una vision se concretara al periodo del 2014 al 2030. Los supuestos utilizados para realizar las simulaciones numericas con el sistema LEAP se detallan tanto en el anexo 10 con la informacion recabada del grupo de enfoque sobre los parametros a usarse en esta tarea, como en el anexo 14 que contiene la informacion especifica utilizada asi como los resultados obtenidos en los periodos 2004-2013 y el segundo periodo del 2014-2030.

  14. Diffusion Parameters of BeO by the Pulsed Neutron Method; Calcul des Parametres de Diffusion de BeO par la Methode des Neutrons Pulses; Opredelenie diffuzionnykh parametrov BeO s pomoshch'yu metoda impul'snykh nejtronov; Determinacion de los Parametros de Difusion en el BeO por el Metodo de los Neutrones Pulsados

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, B. V.; Nargundkar, V. R.; Subbarao, K. [Atomic Energy Establishment Trombay, Bombay (India)

    1965-08-15

    la position et la longueur du compteur d'une part, la position de la source d'autre part, il est possible d'eliminer la plupart des harmoniques spatiaux. Il est egalement possible de tenir compte de n'importe quel bruit de fond constant pour le calcul de la constante de decroissance. Il faut eviter les laplaciens tres eleves afin de ne pas avoir d {sup h}armoniques du temps. Tous les harmoniques qui restent sont rendus inoperants par un retard en temps adequat. Les auteurs ont determine la constante de decroissance du mode fondamental de la population de neutrons thermiques pour plusieurs laplaciens. Ils discutent les conditions a remplir pour une determination exacte de la constante du refroidissement par diffusion C. Pour la glucine, ils ont obtenu les constantes suivantes: {lambda}{sub 0} (constante d'absorption) = 156, 02 {+-} 4, 37 s{sup -1}. D (coefficient dediffusion) = (1,3334 {+-} 0,0128) * 10{sup 5} cm{sup 2}/s, C (constante du refroidissement de diffusion) = (-4,8758 {+-} 0,5846) * 10{sup 5} cm{sup 4}/s. Les auteurs ont etudie le role que peut jouer, dans la determination des parametres de diffusion, le fait que la contribution du terme en B{sup 6} est neglige; ils montrent qu'il est considerable. Ce serait la probablement la cause des ecarts entre les valeurs de C obtenues pour un meme ralentisseur par differents chercheurs. (author) [Spanish] Los autores describen el empleo del metodo de los neutrones pulsados para determinar con precision los parametros de difusion en moderadores. Con ayuda de este metodo, han obtenido los parametros de difusion en el BeO. Las rafagas de neutrones se generaron mediante un acelerador en cascada pulsando la fuente ionica y empleando la reaccion Be (d, n). Como detector se utilizo un contador proporcional de BF{sub 3} enriquecido. Los autores demuestran que por seleccion adecuada de la posicion y longitud del contador y de la ubicacion de la fuente, pueden eliminarse la mayoria de los armonicos espaciales. En el calculo de

  15. Valuacion de empresas de Telecomunicaciones con parametros operativos.

    Directory of Open Access Journals (Sweden)

    Saldaña, J.

    2008-01-01

    Full Text Available The value of telecommunication companies measured in terms of their stock value, may be explained not only by their historical financial results and their financial expectations, but also by the evaluation of other operative factors such as: technological change, organizational change, market strategy, acquisition cost, customers portfolio, fusions and institutional changes (regulations. Due to the importance of the telecommunication sector in the stock market, as well as in the national economy, an analysis which improves its knowledge and allows a better valuation of these companies is required. Models for asset pricing CAPM (Capital Asset Price Model and APT (Arbitrage Price Theory have been developed and proved outside national context, besides, according to theory; their effectiveness for determining stock price depends on the stock market efficiency.

  16. Contribuicao da atividade vagal em parametros eletrofisiologicos supraventriculares de atletas

    OpenAIRE

    Ricardo José Stein

    1997-01-01

    Fundamento: Atletas praticantes de atividades aeróbias apresentam maior freqüência de alterações na condução aírioventricular (AV). Pouco se conhece, porém, a respeito das modificações que ocorrem no sistema excitocondutor em indivíduos treinados aerobicamente com eletrocardiograma de repouso normal. Objetivo; Estudar a associação entre o automatismo sino-atrial e a condução AV com a atividade vagai em atletas praticantes de atividades aeróbias e em sedentários normais. Delineamento: Estudo t...

  17. Determination of D{sub 2}O-2% Enriched Uranium Lattice Parameters by Means of a Critical System; Determination des Parametres d'un Reseau Uranium Enrichi a 2%-Eau Lourde au Moyen d'un Ensemble Critique; Opredelenie s pomoshch'yu kriticheskoj sistemy parametrov reshetki s 2%-nym obog ashcheniem Urana i s zamedlitelem D{sub 2}O; Determinacion, Mediante un Conjunto Critico, de los Parametros de un Reticulado de D{sub 2}O y Uranio Enriquecido al 2%

    Energy Technology Data Exchange (ETDEWEB)

    Raisic, N.; Takac, S.; Markovic, H.; Bosevski, T. [Boris Kidric Institute of Nuclear Sciences, Belgrade, Yugoslavia (Serbia)

    1964-02-15

    faits par la theorie de la diffusion a deux groupes. Les mesures, pour dix configurations de reseau differentes, comportaient la determination du laplacien, du coefficient du niveau d'eau et des facteurs de desavantage pour le flux de neutrons thermiques et epither- miques a l'interieur d'une cellule. Le memoire decrit les methodes de mesure. Les auteurs utilisent ensuite les donnees experimentales pour en deduire les parametres de reseau determines par le calcul du coeur du reacteur au moyen de la formule des quatre facteurs et dans une theorie de diffusion a deux groupes. Ils comparent ces resultats avec les calculs classiques des memes parametres pour des configurations de reseau ayant fait l'objet de mesures. Ils ont constate des ecarts dans la valeur de n et de l'integrale de resonance pour {sup 238}U. En conclusion, les auteurs analysent l'utilite et l'exactitude des informations recueillies a l'aide des montages critiques en vue de l'etude et de l'exploitation d'un reacteur de recherche a uranium enrichi et eau lourde. (author) [Spanish] En la memoria se describe una serie de experimentos efectuados con objeto de determinar los parametros basicos de un reticulado de D{sub 2}O y uranio enriquecido al 2% Los elementos combustibles consistian en cilindros huecos, revestidos de aluminio, con agua pesada en el interior y en el exterior. Los experimentos se realizaron en el conjunto critico RB del Instituto de Ciencias Nucleares 'Boris Kidric' (Belgrado). La geometria sencilla de este conjunto facilita la interpretacion teorica de los resultados experimentales, asi como la comparacion directa con calculos efectuados segun la teoria de difusion de dos grupos. Entre las mediciones efectuadas para diez configuraciones diferentes de reticulado, figuraban la determinacion del laplaciano, del coeficiente de reactividad del nivel de agua y de los factores de desventaja para un flujo de neutrones termico y epitermico dentro de una celda del reactor. En la memoria se describen

  18. Application of monitoring techniques of operational parameters for the implementation of preventive and predictive maintenance programs to gas turbines; Aplicacion de tecnicas de monitoreo de parametros operacionales para la implantacion de programas de mantenimiento predictivo y preventivo en turbinas de gas

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez Villareal, Julio Cesar

    1998-12-31

    components. These techniques are: hardness testing, liquid penetrant inspection, magnetic particle inspections and metallographic examination. Chapter five describes the boroscopy inspection and its applications for a rotor analysis and gas turbine blades. Chapter six shows the results obtained and give recommendations for the vibration analysis that were carried out at a gas turbine facility. [Espanol] Esta tesis se realiza con la finalidad de implantar un programa de mantenimiento preventivo y predictivo, mediante tecnicas de monitoreo de parametros que permita sistematizar, documentar y administrar las actividades del mantenimiento. La metodologia de mantenimiento aqui descrita, se aplica a las turbinas de gas de la Terminal Maritima Dos Bocas Tabasco, Mexico. El mantenimiento preventivo se basa en la revision periodica de los equipos, mediante listas de inspeccion, donde la idea es detectar problemas que provoquen posibles fallas y realizar la reparacion o ajusted necesarios para evitarlo. Sin embargo enfrenta a la posibilidad de que el equipo este en perfecto estado y al estar en revision, tenga retrasos y problemas de arranque posteriores. El mantenimiento predictivo se basa en tecnicas que permiten la deteccion e identificacion de fallas incipientes en los equipos. Las tecnicas recomendadas en esta tesis son: Analisis de vibraciones; Evaluacion no destructivas e Inspeccion boroscopica. La estructura de la tesis consta de los capitulos siguientes: El capitulo uno describe la importancia de los programas y estrategias del mantenimiento, sus ventajas y desventajas al aplicarlas en las plantas de proceso continuo. Se plantean los procedimientos para el diseno de un programa de mantenimiento. El capitulo dos presenta la manera de planear los recursos y materiales de mantenimiento, las tecnicas de inspecciones aplicados a la turbina de gas, y finalmente se disenan listas de verificacion de inspecciones como herramienta del mantenimiento preventivo. Los capitulos siguientes

  19. Measurement of resonance parameters of cross-sections affecting fast-neutron propagation in various media; Mesure des parametres de resonance de sections efficaces lies a la propagation des neutrons dans differents milieux; Izmerenie parametrov rezonansnoj struktury sechenij, vliyayushchikh na rasprostranenie bystrykh nejtronov v sredakh; Medicion de los parametros de resonancia de las secciones eficaces que afectan a la propagacion de los neutrones rapidos en distintos medios

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaev, M N; Filippov, V V; Bondarenko, I I [Academy of Sciences, Moscow, Union of Soviet Socialist Republics (Russian Federation)

    1962-03-15

    propagacion de los neutrones en la materia abarca desde algunas decenas de kiloelectron-voltios , para los nucleos pesados, hasta unos cuantos mega-electron-voltios, para los nucleos intermedios. Para poder tener en cuenta los efectos de resonancia en el calculo de los parametros de los grupos, es indispensable conocer no solo las secciones eficaces medias correspondientes a las reacciones de los neutrones con la materia, sino tambien algunas magnitudes tales como (1/{Sigma}{sub t}), (1/{Sigma}{sub t}{sup 2}) etc. - los corchetes indican que se toman valores promedios de los grupos energeticos. La informacion de que se dispone actualement acerca de los parametros de resonancia en el terreno de los neutrones rapidos no permite calcular las magnitudes mencionadas con la exactitud necesaria. Por tal razon interesa medir directamente (1/{Sigma}{sub t}), (1/{Sigma}{sub t}{sup 2}) y otros valores analogos. Los autores presentan los resultados de las mediciones de una serie de parametros tales como ({Sigma}{sub t}), ({Sigma}{sub t}{sup 2}), (1/{Sigma}{sub t}), (1/{Sigma}{sub t}{sup 2}), (1/{Sigma}{sub t}{sup 3}), etc. que caracterizan la estructura de las secciones eficaces de una serie de nucleos intermedios para neutrones de energia comprendida entre 300 keV y 3 MeV. Dichos valores se dedujeron analizando las curvas de paso a traves de la materia, obtenidas con una geometria favorable, hasta un valor limite de 10{sup -2}, aproximadamente . Los datos obtenidos demuestran que los efectos de resonancia ejercen una notable influencia sobre las caracteristicas de la difusion en la materia. (author) [Russian] Pri sostavlenii sistem mnogogruppovykh konstant dlya rascheta reaktorov na bystrykh i promezhutochnykh nejtronakh vo mnogikh sluchayakh neobkhodimo uchityvat' ehffekty samoehkranirovki , svyazannye s rezonansnoj strukturoj sechenij. EHnergeticheskaya oblast', v kotoroj rezonansnaya struktura okazyvaet sushchestvennoe vliyanie na rasprostranenie nejtronov v veshchestve

  20. Kinetic Storage as an Energy Management System; El almacenamiento cinetico como sistema de gestion de la energia

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Tabares, L.

    2007-07-01

    The possibility of storing energy is increasingly important and necessary. The reason is that storage modifies the basic equation of the energy production balance which states that the power produced should equal the power consumed. When there is a storage device in the grid, this equation is modified such that, in the new balance, the energy produced should equal the algebraic sum of the energy consumed and the energy stored (positive in storage phase and negative when released). This means that the generation profile can be uncoupled from the consumption profile, with the resulting improvement of efficiency. Even small-sized storage systems can be very effective. (Author) 10 refs.

  1. Kinetic study of the gum decomposition from brazilian gasoline; Estudo cinetico da decomposicao da goma oriunda de gasolina brasileira

    Energy Technology Data Exchange (ETDEWEB)

    Pivesso, Paulo Roberto; Galvao, Luzia Patricia Fernandes de Carvalho; Fernandes Junior, Valter Jose; Coutinho, Ana Carla S.L.S. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil); Souza, Antonio Gouveia de [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil)

    2004-07-01

    The modern gasoline contains in your composition insatured hydrocarbons that can be degraded by the action of the air, heat and substances presenting catalytic activity. The presence of air and heat promote oxidation reactions and polymerization, which promote the gum formation, that is a product with diverse characteristics. The petroleum and l the automobile industries have been investing in researches to lessen the gum undesirable effects. Nowadays, several products are added to the gasoline, for example, the surfactant additives, with the purpose to reduce the formation of deposits in the engine. This work evaluated the influence of a polyester amine addictive, used as the main active component in Brazilian gasoline. The gums were generated evaporating the gasolines according to the ASTM D 381 method. Two types of gum were obtained; the Common Washed Gum (White Sample) and the Additive based Washed Gum (Additive Sample). Both samples were characterized for thermal analysis and submitted for a kinetic study using the model-free method proposed by Vyazovkin. This approach was applied to the final stage of the gums decomposition, supplying the corresponding relative kinetic parameters, such as energy of activation and conversion (author)

  2. Some Possibilities of the Eddy-Current Method for Multi-Parameter Testing of Structural Components; Quelques Possibilites Offertes par la Methode des Courants de Foucault pour le Controle de Nombreux Parametres des Elements de Construction; Nekotorye vozmozhnosti metoda vikhrevykh tokov dlya mnogoparametrovogo kontrolya ehlementov konstruktsij; Algunas Posibilidades que Brinda el Metodo de las Corrientes de Foucault para Controlar Numerosos Parametros de los Elementos de Construccion

    Energy Technology Data Exchange (ETDEWEB)

    Vjahorev, V. G.; Gerasimov, V. G.; Deniskin, V. P.; Trahtenberg, L. I.; Shkarlet, Ju. M. [Gosudarstvennyj Komitet po Ispol' zovaniju Atomnoj Jenergii SSSR, Moskva, SSSR (Russian Federation)

    1965-09-15

    donnees calculees et experimentales, les auteurs indiquent diverses possibilites de realisation de detecteurs a courants de Foucault de frequence unique permettant le controle avec modification simultanee de plusieurs parametres. (author) [Spanish] Los autores demuestran que los problemas del control no destructivo de diversos parametros se plantean en la tecnologia nuclear segun ciertas leyes y que el metodo de las corrientes de Foucault se adapta particularmente a la solucion de varios de esos problemas. Los autores justifican la utilizacion de modelos electricos para resolver problemas de control con ayuda de una larga bobina hueca. Presentan formulas y exponen un metodo para el calculo de detectores a base de corrientes parasitas. Describen un dispositivo que permite verificar el espesor de las paredes de tubos; en este dispositivo, el desplazamiento del tubo a controlar no ejerce influencia alguna sobre los resultados de las mediciones, gracias al empleo de un monitor accionado por una senal dependiente de la fase de tension del detector. En calidad de detector se ha empleado un dispositivo destinado al control de los tubos de un autogenerador despues de haber incluido en su circuito una bobina de ensayo. Partiendo de datos calculados y experimentales, los autores senalan diversas posibilidades de realizacion de detectores a base de corrientes de Foucault de frecuencia unica, que permiten efectuar el control con modificacion simultanea de varios parametros. (author) [Russian] Pokazana zakonomernost' voznikno- venija zadach o nerazrushajushhem mnogoparametrovom kontrole v jadernoj tehnologii i celeso- obraznost' reshenija nekotoryh iz nih metodom vihrevyh tokov. Obosnovano primenenie jelektricheskih modelej dlja reshenija zadach kontrolja s ispol'zovaniem dlinnoj prohodnoj katushki. Privodjatsja raschetnye formuly i izlagaetsja metodika rascheta nakladnyh toko- vihrevyh datchikov. Opisana shema pribora dlja kontrolja tolshhiny stenki trub, v kotorom vlijanie pereme

  3. Buli. Mater. Sci., Vol. 20, No. 2, April 1997, pp. 247-257. (C

    Indian Academy of Sciences (India)

    Synthesis of spodumene and spodumene-zirconia composite ... were prepared using aqueous sol-gel method employing lithium formate, aluminium formate, ... synthesis and the processing of spodumene using different precursor compounds.

  4. RBE of some Sodium, Water and Bioelectric Parameters of Gastro-Intestinal Absorption; L'EBR pour le Transport du Sodium et de l'Eau et pour Certains Parametre Bioelectriques dans l'Absorption Gastro-Intestinale; Obeh v otnoshenii nekotorykh natrievykh, vodnykh i bioehlektricheskikh parametrov vsasyvaniya v zheludochno-kishechnom trakte; La EBR Para el Transporte del Sodio y del Agua y Para Ciertos Parametros Bioelectricos en la Absorcion Gastrointestinal

    Energy Technology Data Exchange (ETDEWEB)

    Vaughan, B. E.; Davis, A. K.; Cummins, J. T.; Alpen, E. L. [US Naval Radiological Defense Laboratory, San Francisco, CA (United States)

    1964-05-15

    que aplicaron para efectuar determinaciones bioelectricas y de flujos unidireccionales. Expusieron ratas y perros a neutrones rapidos y a rayos X de 250 kVp (ratas)y de 1000 kVp (perros). Los animales fueron sometidos a una exposicion bilateral de cuerpo entero y en cada caso se determino la dosis profunda. En la rata, a los siete dias a contar de la irradiacion, la actividad bioelectrica en el estomago se reduce notablemente con respecto a la normal, pero no ocurre lo mismo en los tramos inferiores del conducto gastrointestinal. Puede asignarse un valor comprendido entre 2 y 3 a la EBR correspondiente a la reduccion diferida de la actividad bioelectrica gastrica y este efecto se comprueba facilmente con dosis neutronicas de 160 rad (primer choque). En el perro, tres dias despues de la irradiacion, las velocidades de transporte unidireccional del plasma al lumen se reducen, tanto para el sodio como para el agua. Este efecto se observa despues de aplicar 1200 r de rayos X (dosis en el aire) y de dosis neutronicas de 300 rad o bien de 600 rad (primer choque). En cambio, con dosis de 600 r de rayos X (en el aire), dichas velocidades de transporte no disminuyen y se manifiesta la tendencia opuesta. De la reduccion diferida de los transportes del plasma al lumen puede deducirse que el valor de la EBR esta comprendido entre 2 y 6. El mecanismo electrogenico en el estomago del raton, segun estos estudios, posee especificidad con respecto al ion sodio, a diferencia de lo que ocurre en la rana. Los potenciales in vitro coinciden con los determinados in vivo y solo son afectados por el envenenamiento metabolico o la sustitucion del sodio. Comparadas con las mediciones de los parametros bioelectricos, las determinaciones de flujos son mas especificas; sin embargo, su acentuada variabilidad biologica limita su utilidad. En los flujos unidireccionales, del plasma al lumen, se observa una modalidad de alteracion constante en funcion de la irradiacion, que indica que la

  5. Kinetic behavior of manganese in mangrove ecosystem - Itacuruca, Rio de Janeiro State, Brazil; Comportamento cinetico do manganes numa floresta de manguezal - Itacuruca, RJ

    Energy Technology Data Exchange (ETDEWEB)

    Canesin, Fatima de Paiva; Bellido Junior, Alfredo Victor [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Inst. de Quimica. Lab. de Quimica Nuclear; Bellido, Luis Fernando [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

    2002-07-01

    The redox cycling of manganese has pronounced effects on the adsorption of trace elements onto oxide surfaces is leaving these unavailable for the biota. Specific constants for the kinetics oxidation reaction of Mn in mangrove ecosystems have been measured. Water samples with different characteristics were collected in a tidal creek in a mangrove forest growth at Itacuruca, RJ. The methodology used to study the kinetics was, incubation of the water, in laboratory, with Mn-54. The oxides precipitates were filtered at constant intervals of time. The Mn-54 decay on the filters and filtrates were counted, for 600 s, in HPGe and associated electronics ORTEC. Ln A x t diagram showed an autocatalytic kinetic behavior. Temperature, pH, O{sub 2} dissolved, salinity, Mn (II) and Mn (IV) were appraised. The rate constant k{sup '}{sub 1}1 varied from 1,0 x 10{sup -5} to 4,0 x 10{sup -5} s{sup -1}. The k{sup '}{sub 2} rate constant had a larger variation, according to the other kinetic model that shows more of a heterogeneous affect, or catalysis via bacteria. We found a mean half life for Mn(II) of 12 h for the homogeneous kinetics in the mangrove. Rate constants increased with the pH, temperature, O{sub 2} dissolved, tide height, and decrease with salinity. (author)

  6. Studies of pyrolysis kinetics of sewage sludge obtained from dynamic experiments; Estudio cinetico de la pirolisis de fangos mediante experimentos dinamicos

    Energy Technology Data Exchange (ETDEWEB)

    Arauzo, J; Gonzalo, A; Sanchez, J L [Universidad de Zaragoza, Madrid (Spain). Inst. de Investigacion en Ingenieria de Aragon. Grupo de Procesos Termoquimicos; Resende, F L.P. [University of Michigan, Ann Arbor, MI (United States). Dept. of Chemical Engineering; Rocha, J D [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Nucleo Interdisciplinar de Planejamento Energetico (NIPE); Mesa Perez, J M [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Fac. de Engenharia Agricola

    2004-07-01

    In this work, a pyrolysis model is presented in order to describe the pyrolysis kinetics of sewage sludge. Data were obtained from dynamic experiments, at heating rates of 5 to 20 deg C/min and in a temperature range of 40 to 900 deg C. A simple first order or near first order can predict reasonably well the final conversion reached, but, in what concerns the weight loss rate, a simple model cannot predict the peaks obtained in the weight loss rate. As it is shown, the best fit has been obtained by a model which takes into account four fractions which decompose independently following a first order kinetics. (author)

  7. Estudo cinetico de dissolução/oxidação do mercurio metalico em solução aquosa de cloreto de sodio

    OpenAIRE

    Maria Elizabeth Afonso de Magalhães

    1995-01-01

    Resumo: O mercúrio metálico tem sido descrito na literatura ambiental e toxicológica como pouco reativo, e consequentemente como não ou pouco tóxico. A toxicidade deste elemento tem sido normalmente associada aos íons alquil-mercúrio, que parecem serem formados por alguns microorganismos. Neste trabalho, são descritos experimentos apontando que o mercúrio metálico pode ser facilmente oxidado pelo oxigênio molecular dissolvido em solução aquosa, na presença de espécies como o cloreto , que com...

  8. Kinetic and allometric models for dosimetry using radiopharmaceuticals labeled with lanthanides; Proposicao de modelos cineticos e alometricos para a dosimetria de radiofarmacos marcados com lantanideos

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Marina Ferreira

    2012-07-01

    This work proposes two models based in compartmental analyses: Animal model and Human model, using images from gamma camera measurements to determinate the kinetic constants of the {sup 177}Lu-DOTATATE to three animal species (rat Wistar, Armenian hamster and Syrian hamster) and to the human in biodistribution studies split in two phases: Phase 1 governed by uptake from the blood and Phase 2 governed by the real excretion. The kinetic constants obtained from the animals' data ere used to build allometric scaling to predict radiopharmaceutical biodistribution in the human employing relations by mass, metabolism, by life span and by physiological parameters. These extrapolation results were compared with the PRRT (Peptide receptor radiotherapy) patients kinetic data calculated using the Human model. The kinetic constants obtained from humans were used in dose assessment to PRRT patients considering MIRD 26 organs and tissues. Dosimetry results were in agreement with available results from literature. For the Phase 1 allometric scaling from kinetic data from the blood to the organs straight responsible for the {sup 177}Lu-DOTATATE metabolism and excretion - liver, kidneys and urinary bladder -show good correlation in the scaling by mass, metabolism and physiological and parameters. For the Phase 2, only the kinetic data from blood to the liver and to the kidneys show good correlation. Based in the anaesthetics inhibitory action over the renal excretion, there is not empirical basis to allow measurement times over 40 minutes in in vivo studies with small animals. Consequently, the Phase 1 results seem enough to make allometric scaling to assessment dose in PRRT. (author)

  9. Kinetic study of the annealing reactions in Cu-Ni-Fe alloys; Estudio cinetico de las reacciones de recocido en aleaciones de Cu-Ni-Fe

    Energy Technology Data Exchange (ETDEWEB)

    Donoso, E.

    2014-07-01

    The thermal aging of a Cu-45Ni-4Fe, Cu-34Ni-11Fe and Cu-33Ni-22Fe alloys tempered from 1173 K have been studied from Differential Scanning Calorimetry (DSC) and microhardness measurements. The analysis of DSC curves, from room temperature to 950 K, shows the presence of one exothermic reaction associated to the formation of FeNi{sub 3} phase nucleating from a modulate structure, and one endothermic peak attributed to dissolution of this phase. Kinetic parameters were obtained using the usual Avrami-Erofeev equation, modified Kissinger method and integrated kinetic functions. Microhardness measurements confirmed the formation and dissolution of the FeNi{sub 3} phase. (Author)

  10. Characteristic parameters of drift chambers calculation; Calculo de los parametros caracteristicos de camaras de deriva

    Energy Technology Data Exchange (ETDEWEB)

    Duran, I; Martinez-Laso, L

    1989-07-01

    We present here the methods we used to analyse the characteristic parameters of drift chambers. The algorithms to calculate the electric potential in any point for any drift chamber geometry are presented. We include the description of the programs used to calculate the electric field, the drift paths, the drift velocity and the drift time. The results and the errors are discussed. (Author) 7 refs.

  11. Determination of the TLD-100 physical parameters; Determinacion de parametros fisicos del TLD-100

    Energy Technology Data Exchange (ETDEWEB)

    Paucar J, J.; Picon C, C. [Instituto Nacional de Enfermedades Neoplasicas. INEN. Av. Angamos Este 2520, Lima 34 (Peru)

    1998-12-31

    This study was realized in the Physics service at the Radiotherapy Department of the National Institute of Neoplasic Diseases in Lima, Peru, it was determined the activation energy, the kinetic order and the frequency factor of the fifth peak of the TLD-100 thermoluminescent spectra using different algorithms. This was carried out in parallel with the implementation and design of a software and an interface associated with the Tl lecturer which allows a semiautomatic control for a thermoluminescent lecturer process. (Author)

  12. Analise dos efeitos de diferentes parametros na estabilidade de vitamina C em vegetais processados

    OpenAIRE

    Marta de Toledo Benassi

    1990-01-01

    Resumo: O trabalho foi conduzido no sentido de se estudar a estabilidade e verificar a cinética de perda de vitamina C em diferentes processos, utilizando-se como, matéria prima, vegetais selecionados: couve, couve-flor e pimentão. Foram feitos diferentes tipos de cozimento (água, vapor e microondas) e estocagem (temperatura ambiente, refrigerada e congelada), variando-se os tempos e condições de processamento. Foi constatado que as perdas de vitamina C nos produtos, durante o cozimento em ág...

  13. Tecnicas de fisioterapia respiratoria: efeito nos parametros cardiorrespiratorios e na dor do neonato estavel em UTIN

    Directory of Open Access Journals (Sweden)

    Renata Martins

    2013-12-01

    Full Text Available OBJETIVOS: verificar os efeitos de técnicas de fisioterapia respiratória (TFR na dor e na função cardiorrespiratória de recém-nascidos (RN clinicamente estáveis com prescrição de TFR, internados em unidade de terapia intensiva neonatal. MÉTODOS: ensaio clínico randomizado cego. Os RN foram alocados em três grupos: G1-controle; G2- fisioterapia convencional; G3-reequilíbrio tóracoabdominal. Neonatos do G2 e G3 receberam intervenção em atendimento único. Todos foram avaliados antes, imediatamente após e 15 minutos após o término da intervenção/repouso quanto aos parâmetros cardiorrespiratórios (saturação periférica de oxigênio/SpO2, frequências cardíaca/fc e respiratória/fr e dor (escalas específicas: NIPS, NFCS e PIPP. Para análise dos dados foram aplicados: testes qui-quadrado, Friedman, Kruskal- Wallis e, posteriormente, análise de comparações múltiplas, com p0,05 e em relação à dor houve mudanças significativas nas escalas NIPS (G1 e G2, p=0,037 e p=0,011, respectivamente e PIPP (G2, p=0,005. CONCLUSÕES: técnicas de fisioterapia respiratória não desencadearam dor, nem instabilidade cardiorrespiratória nos RN estudados.

  14. Los Modelos CAPM y APT para la valuacion de empresas de Telecomunicaciones con parametros operativos

    Directory of Open Access Journals (Sweden)

    Saldaña, J.

    2007-07-01

    Full Text Available One of the most important research topics in the financial area during de the last years has been the capital assets appraisal or the appraise of shares. This seeks two determine the explanatory factor of the rate of return for a specific portfolio. The CAPM (Capital Asset Pricing Model and the APT (Arbitrage Pricing Theory, both capital asset evaluation models, are hereby presented. The main characteristics of both models are the essential assumptions for their for there development, their statement and the practical test on the telecommunications portfolio using operational, financial and macroeconomics variable, and carried on with the purpose to be compare with reality.

  15. Secagem de tomate (Lycopersicon esculentum Mill) para conserva : estudo de parametros com base na qualidade final

    OpenAIRE

    Gisele Anne Camargo

    2000-01-01

    Resumo: o tomate seco tem apresentado crescente aplicação na culinária brasileira, principalmente, como ingrediente de massas, pizzas e também no consumo imediato. Com a finalidade de estudar a influência de parâmetros de secagem sobre a eficiência do processo e sobre a qualidade do produto final, foi desenvolvida uma pesquisa utilizando tomates de duas variedades: uma variedade industrial (Rio Grande) e outra de tomate de mesa (Debora Plus). Cada uma das variedades foi analisada quanto ao co...

  16. Monitor of dynamic parameters in real time; Monitor de parametros dinamicos en tiempo real

    Energy Technology Data Exchange (ETDEWEB)

    Rojas S, A.S.; Ruiz E, J.A. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)

    2008-07-01

    In the complex physical systems exist parameters that are necessary for monitoring in real time. In the nuclear industry, particularly in a reactor this surveillance is important, where the times of the reactions are almost instantaneous. Although many of these parameters are monitored, given the advance of the computer systems the monitoring could either be enlarged direct or indirect of other parameters. The analysis of the neutron noise in the nuclear reactors, plays an important role, the noise signal it contains information about the operation conditions of a system, when analyzing it with analysis methodologies of analogical signals to provide important information for the early detection of possible flaws and to indicate the permissible operation levels. To show the characteristics of the operation of the system of Monitoring of Dynamic Parameters in Real Time, oscillations of neutron noise of the TRIGA Mark III of the ININ were analyzed, these were caused with the control bar to a power of 10 Watts, the oscillations were carried out to a frequency of 1Hz, signal of low frequency. In this work a virtual instrument that allows by means of the spectral analysis method in frequency point by point is presented, to indicate in real time periodic variations that could be presented in the neutron noise signal, visualizing in advance the dynamic behavior of the system or nuclear plant. Another of the tests of the monitoring system presented is that of the oscillatory event happened in the reactor of Laguna Verde Nucleo electric Central, would be convenient to have an instrument of surveillance for monitoring through the neutron noise signal the behavior of some important parameter to predict and to indicate in an immediate way an abnormal condition in the reactor operation or in the plant system. These parameters can be the power, the recirculation water flow, etc. The monitor is based on a personal computer (PC), a data acquisition card (ADC) and a computer program developed with LabVIEW graphic programming, the monitor presents the system behavior with graphic screens, showing the signals in the time domain and in the frequency domain. (Author)

  17. INFLUENCIA DEL TRATAMIENTO CON AMINAS EN LOS PARAMETROS HEMODINAMICOS y METABOLICOS EN EL SHOCK SEPTICO EXPERIMENTAL

    Directory of Open Access Journals (Sweden)

    Felisa Alonso Garcia,

    2003-01-01

    Full Text Available OBJETIVO: Estudiar las variaciones hemodinámicas y metabólicas de las primeras fases del Shock Séptico Experimental (SSE, inducidas por el tratamiento con distinta asociación de aminas. METODO: Investigación experimental en 22 perros. Se les indujo SSE mediante la administración de endotoxina de E. Coli (Serotipo 0111 B.M. Difco Laboratories. Michigan. USA. En función del tiempo se establecieron 5 fases: Basal ó "t=0" (considerado tiempo 0, SSE ó "t=30" (a los 30 minutos del inicio de la infusión del estímulo séptico, "t = 60", "t = 90" y "t = 120" a los 60, 90 y 120 minutos respectivamente de la administración de la endotoxina. En relación al tratamiento administrado, se distinguieron 3 grupos: Grupo A (n=7: tratamiento de soporte; Grupo B (n=8: Dopamina a 10 mcg/kg/min y Dobutamina a 5 mcg/kg/min (DPDB en la fase "t=60", DPDB más Noradrenalina (NA a 0,5 mcg/kg/min (NA0,5 en la fase "t=90"; DPDB más NA a 1 mcg/kg/min (NA1 en la fase "t=120"; Grupo C (n=7: Dopexamina a 12 mcg/kg/min (DX en la fase "t=60", DX más NA0,5 en la fase "t=90" y DX más NA1 en la fase "t=120". La comparación estadística se realizó mediante: "t" de Student-Fisher, Análisis de la Varianza, Chi Cuadrado y cálculo de la potencia estadística en caso necesario. RESULTADOS: Grupo B respecto al A: DP-DB NA0.5 aumentó la Frecuencia cardiaca (FC; DPDB-NA1 además incrementó la Presión diastólica (TAD. Grupo C respecto al A: DX- NA0,5 aumentó la FC; DX- NA1, incrementó la FC y TAD. CONCLUSIONES: La FC, TAS y TAD, se modificaron significativamente con las diversas asociaciones de aminas, mientras que no se evidenciaron variaciones intergrupo de la glucemia y plaquetas. Los cambios significativos en las últimas fases de la investigación experimental, de la glucemia y de las plaquetas, fueron secundarios a la progresión del shock séptico experimental y no a la diferente terapia recibida en cada grupo (ya que se comportaron de forma independiente al tratamiento administrado.

  18. COMPARACION DE 13 INTERVALOS DE CONFIANZA PARA LOS PARAMETROS DE LA DISTRIBUCION MULTINOMIAL

    Directory of Open Access Journals (Sweden)

    Difariney González-Gómez

    2015-07-01

    Full Text Available La distribución multinomial es fundamental para la descripción de fenómenos en los que pueden ocurrir k > 2 eventos excluyentes, cada uno con probabilidad π = (π1, π2, . . . , πk. Algunos ejemplos de esta distribución incluyen la calidad de un producto o encuestas de selección múltiple. Un problema de gran interés en inferencia estadística es la construcción de intervalos de confianza los parámetros para π. En este trabajo se comparan, a través de un estudio de simulación, 13 metodologías para la construcción de intervalos de confianza para dicha distribución. Utilizando como criterios de comparación el nivel de confianza nominal, la longitud del intervalo y una combinación de estos, se encuentra que los intervalos de confianza basados en el Teorema del Límite Central no presentan el mejor desempeño. Finalmente se recomiendan los métodos basados en la distribución F (Leemis, 1996, seguido del método de verosimilitud relativa (Kalbfleish, 1985 y Quesenberry & Hurst (1964.

  19. Determination of electrodebiles parameters of quark b; Determinacion de los parametros electrodebiles del quark b

    Energy Technology Data Exchange (ETDEWEB)

    Chamizo Llatas, M.

    1995-07-01

    In the present work we analyze the process e{sup e{yields}}bb with the data collected during 1991 and 1992 by the Z,3 detector situated in the LEP e{sup es}torage-ring (CERN). From the measurements of the cross-sections and the charge asymmetry we determine the parameters of the b quark in the framework of the Standard Model. Finally, we parametrize the possible deviations from the model an obtain upper and lower. limits for the mass of the t quark. (Author) 23 refs.

  20. Pt, PtCo and PtNi electrocatalysts prepared with mechanical alloying for oxygen reduction reaction in alkaline medium; Electrocatalizadores de Pt, PtCo y PtNi preparados por aleado mecanico para la reaccion de reduccion de oxigeno en medio alcalino

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Contreras, M.A.; Fernandez-Valverde, S.M. [Instituto Nacional de Investigaciones Nucleares, Ocoyoacac, Estado de Mexico (Mexico)]. E-mail: miguel.garcia@inin.gob.mx; Vargas-Garcia, J.R. [ESIQIE-IPN, Mexico D.F. (Mexico

    2009-09-15

    Pt, PtCo and PtNi electrocatalysts were prepared using mechanical alloying and their electrocatalytic activity was investigated for oxygen reduction reaction (ORR) in KOH 0.5 M using cyclic voltametry and rotary disc electrode (RDE) techniques. The electrocatalysts were characterized using x-ray diffraction, sweep electron microscopy, dispersive x-ray transmission and chemical analysis. The physical characterization indicated that all the electrocatalysts are alloys formed by agglomerated particles composed of nanocrystals. The chemical analysis showed the presence of iron in the alloys. For the electrocatalytic evaluation, polarization curves and Koutecky-Levich and Tafel graphs were obtained to determine the kinetic parameters of the electrocatalysts in the study. With the same experimental conditions, the PtCo presented better electrocatalytic performance with a higher exchange current density. [Spanish] Se prepararon electrocatalizadores de Pt, PtCo y PtNi por aleado mecanico y se investigo su actividad electrocatalitica para la reaccion de reduccion de oxigeno (RRO) en KOH 0.5 M utilizando las tecnicas de Voltametria ciclica y Electrodo de Disco Rotatorio. Los electrocatalizadores se caracterizaron por difraccion de rayos X, Microscopia electronica de Barrido, de Transmision y analisis quimico por dispersion de rayos X. La caracterizacion fisica indico que todos los electrocatalizadores son aleaciones formadas de particulas aglomeradas, compuestas de nanocristales. El analisis quimico mostro la presencia de hierro en las aleaciones. Para la evaluacion electrocatalitica se obtuvieron curvas de polarizacion, graficas de Koutecky-Levich y de Tafel para determinar los parametros cineticos de los electrocatalizadores en estudio. En las mismas condiciones experimentales, el PtCo presento el mejor desempeno electrocatalitico con la densidad de corriente de intercambio mas alta.

  1. Sensitiveness Analysis of Neutronic Parameters Due to Uncertainty in Thermo-hydraulic parameters on CAREM-25 Reactor; Analisis de Sensibilidad de los Parametros Neutronicos ante Incertezas en los Parametros Termohidraulicos en el Reactor CAREM-25

    Energy Technology Data Exchange (ETDEWEB)

    Serra, Oscar [Comision Nacional de Energia Atomica, Centro Atomico Bariloche (Argentina)

    2000-07-01

    Some studies were done about the effect of the uncertainty in the values of several thermo-hydraulic parameters on the core behaviour of the CAREM-25 reactor.By using the chain codes CITVAP-THERMIT and the perturbation the reference states, it was found that concerning to the total power, the effects were not very important, but were much bigger for the pressure.Furthermore were hardly significant in the presence of any perturbation on the void fraction calculation and the fuel temperature.The reactivity and the power peaking factor had highly important changes in the case of the coolant flow.We conclude that the use of this procedure is adequate and useful to our purpose.

  2. Independent procedure of checking dose calculations using an independent calculus algorithm; Verificacion independiente de los parametros de planificacion, histogramas dosis volumen, y parametros radiobioligocs mediante el uso de una hoja de calculo automatizada

    Energy Technology Data Exchange (ETDEWEB)

    Perez Rozos, A.; Jerez Sainz, I.; Carrasco Rodriguez, J. L.

    2006-07-01

    In radiotherapy it is recommended the use of an independent procedure of checking dose calculations, in order to verify the main treatment planning system and double check every patient dosimetry. In this work we present and automatic spreadsheet that import data from planning system using IMPAC/RTP format and verify monitor unit calculation using an independent calculus algorithm. Additionally, it perform a personalized analysis of dose volume histograms and several radiobiological parameters like TCP and NTCP. Finally, the application automatically generate a clinical dosimetry report for every patient, including treatment fields, fractionation, independent check results, dose volume analysis, and first day forms. (Author)

  3. LA HIPERQUERATOSIS CITOLOGICA COMO PARAMETRO INDIRECTO DE LA INFECCIÓN POR EL VIRUS DEL PAPILOMA HUMANO.

    Directory of Open Access Journals (Sweden)

    Victoria Martín Gómez

    2009-01-01

    Full Text Available Introducción. La hiperqueratosis es una lesión epitelial que histológicamente se caracteriza, por presentar un aumento del grosor de la capa epitelial superficial cornificada, con ausencia de núcleos. Entre las causas que favorecen la aparición de hiperqueratosis, se puede resaltar la reacción del epitelio a los estímulos locales, mecánicos, químicos o infecciosos, siendo más relevante en estos casos el virus del papiloma humano. Objetivo: Conocer la relación que existe entre la presencia de hiperqueratosis en los estudios citológicos de cribado y la posible relación con la infección del virus del Papiloma Humano. Material y métodos: Se han estudiado un total de 2372 extendidos citológicos realizados durante un año en el Servicio de Obstetricia y Ginecología del Hospital Clínico de Salamanca. La edad de las pacientes estaba comprendida entre los 16 y 65 años. La toma citológica realizada mediante la técnica de triple toma se depositaba en medio líquido. Se descartaron las citologías que presentaban alteraciones citológicas, y se valoraron 1125 estudios citológicos considerados como negativos. De estos, 316 presentaron hiperqueratosis. A las pacientes que presentaban hiperqueratosis se les realizó estudio colposcópico y determinación de VPH por PCR. Resultados: En el 27% de las hiperqueratosis, la PCR de VPH fue negativa, el resto, positiva. Se ha podido determinar un VPP del 72% y un VPN del 39%. La sensibilidad fue del 46% y la Especificidad del 81%.

  4. Observacion y anatisis de la varlacton de parametros geofisicos de un pozo ubicado en el piedemonte lIanero

    Science.gov (United States)

    Montano Mejia, Felix Humberto

    2001-12-01

    Este articulo presenta el desarrollo de instrumentacion especializada que se diseiio y se puso en funcionamiento con el fin de real izar la observacion y el anal isis de la variacion de parametres geofisicos de un pozo ubicado en el piedemonte llanero. La instrumentacion esta compuesta por una estacion remota para el registro multipararnetro y una estacion local en la cual se analizan los registros bajados de la estacion remota mediante la interrogacion periodica.

  5. Luminescence model with quantum impact parameter for low energies; Modelo de luminiscencia con parametro de impacto cuantico para bajas energias

    Energy Technology Data Exchange (ETDEWEB)

    Cruz G, H.S.; Michaelian, K.; Galindo U, S.; Martinez D, A.; Belmont M, E. [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico- Toluca Km. 36.5, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2000-07-01

    The analytical model of induced light production in scintillator materials by energetic ions proposed by Michaelian and Menchaca (M-M) adjusts very well the luminescence substance data in a wide energy interval of the incident ions (10-100 MeV). However at low energies, that is, under to 10 MeV, the experimental deviations of the predictions of M-M model, show that the causes may be certain physical effects, all they important at low energies, which were not considered. We have modified lightly the M-M model using the basic fact that the Quantum mechanics gives to a different limit for the quantum impact parameter instead of the classic approximation. (Author)

  6. Determination of Tongue and Groove parameters for multileaf collimators; Determinaco de parametros de Tongue and Groove de colimadores de multilaminas

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Aluisio; Almeida, Carlos E. de, E-mail: alu_neto@hotmail.com [Universidade Estadual do Rio de Janeiro (UERJ), RJ (Brazil). Laboratorio de Ciencias Radiologicas; Nguyen, Bihn [Prowess Inc., Concord, CA (United States)

    2012-08-15

    The Tongue and Groove effect (TandG) is characterized by an additional attenuation between adjacent and opposing leaves on multileaf collimators (MLCs) in adjacent or complementary fields. This is a typical situation in of intensity-modulated radiotherapy treatments. The aim of this study was to measure the width and transmission of TandG effect for two commercial MLCs: Varian Millennium 120 (6 MV and 16 MV beams) and BrainLab m3 (only for 6 MV). The methodology used was based on the creation of MLC shapes that emphasizes TandG effect, the irradiation of these fields on radiochromic film and the sensitometric evaluation of the films in order to determine the TandG width and transmission. The results for TandG width for studied MLCs were 2.5, 1.8 and 2 mm, respectively, whit transmission TandG values of 87, 90 and 85%. (author)

  7. The thermoluminescent curve as parameter to compare archaeological ceramics; La curva termoluminiscente como parametro para comparar ceramica arqueologica

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez R, I.R.; Ramirez C, G.A. [Centro INAH Estado de Mexico. Morelos Ote. 502, Col. San Sebastian, 50090 Toluca, Estado de Mexico (Mexico); Gonzalez M, P.R.; Mendoza A, D. [lNIN, Carr. Mexico-Toluca S/N, La Marquesa, 52750 Ocoyoacac, Estado de Mexico (Mexico); Martinez C, G. [Coordinacion Nacional de Conservacion del Patrimonio Cultural, INAH, Mexico D.F. (Mexico)

    2006-07-01

    Most mineral materials, including the constituents of pottery, have the property of thermoluminescence (TL), where part of the energy from radioactive decay in the mineral is stored and later released as light upon strong heating. The intensity of emitted light as a function of temperature is the thermoluminescence glow curve. However, it is well-know the thermoluminescence glow curve form depends of several factors associates with the incident radiation and type of materials. Between the factors associated with the materials, it can be mentioned the quantity and type of crystalline phases, and quantity and type of impurities that they could be present in the material. That is to say, materials with different physicochemical characteristics will produce different thermoluminescence glow curve, although, they have been irradiated under the same conditions. In accordance with the above mentioned, it is possible to identified differences between pre hispanic ceramic belonging to a same site and other sites. In this work a discussion about advantages and disadvantages is presented. Some specific examples in ceramic artifacts belonging to the Matlatzinca and Teotihuacan cultures are included. (Author)

  8. Marking with radioactive iodine of a plasma substitute and preliminary essays of his kinetic behaviour in rats; Marcacao com radioiodo de um sucedaneo do plasma e ensaios preliminares de seu comportamento cinetico em ratos

    Energy Technology Data Exchange (ETDEWEB)

    Cova, Wilma Guimaraes

    1973-07-01

    A blood plasma substitute (Haem accel - PGO), which has as a base a degraded and polymerized gelatin, was labelled with radioactive iodine (I-131) and preliminary essays of its kinetic behavior was done. We have used the labelling method of McFarlaner. The results obtained - radiochemical yield and purity - were favorable. The kinetic behaviour the residual radioactivity studied by measuring the residual radioactivity of the body and excreta in groups of male Wistar rats for a maximum period of 150 hours. These results have shown and excellent correlation for a two components exponential function's adjustment, suggesting therefore a bi compartmental mathematical model. (author)

  9. Thermal-kinetic study of natural rubber latex films vulcanized by using gamma radiation; Estudo termo-cinetico de filmes de latex de borracha natural de Hevea brasiliensis vulcanizada por radiacao gama

    Energy Technology Data Exchange (ETDEWEB)

    Leal, Ana Paula Pinho Rodrigues; Barros, Glaucione Gomes de [Brasilia Univ., DF (Brazil). Inst. de Quimica; Guedes, Selma M.L. [Instituto de Pesquisa em Energia Nuclear, Sao Paulo, SP (Brazil)

    1999-07-01

    Vulcanization of natural rubber latex by ionization radiation produces the crosslink in disperse latex particles. Advantages over conventional process of vulcanization are: the absence of carcinogenic nitrosamines, low cytotoxicity and better degradation at room conditions, due to mainly to the absence of sulfur, zinc oxide and dithiocarbamates. Thermogravimetric analysis (TG) is the measurement of the weight change of a material as a function of temperature and time. TG data different heat speed provide an alternative model of the kinetics of degradation of polymeric materials. The kinetic studies of this material showed a single degradation process at least for 76,5% of mass loss. The activation energy was 49 Kcal/mol. For higher mass loss (85%) the degradation was characterized by associate mechanism. (author)

  10. Marking with radioactive iodine of a plasma substitute and preliminary essays of his kinetic behaviour in rats; Marcacao com radioiodo de um sucedaneo do plasma e ensaios preliminares de seu comportamento cinetico em ratos

    Energy Technology Data Exchange (ETDEWEB)

    Cova, Wilma Guimaraes

    1973-07-01

    A blood plasma substitute (Haem accel - PGO), which has as a base a degraded and polymerized gelatin, was labelled with radioactive iodine (I-131) and preliminary essays of its kinetic behavior was done. We have used the labelling method of McFarlaner. The results obtained - radiochemical yield and purity - were favorable. The kinetic behaviour the residual radioactivity studied by measuring the residual radioactivity of the body and excreta in groups of male Wistar rats for a maximum period of 150 hours. These results have shown and excellent correlation for a two components exponential function's adjustment, suggesting therefore a bi compartmental mathematical model. (author)

  11. Crystallization kinetic study of the lithium-disilicate bioceramic obtained from rice-husk silica starting powder; Estudo cinetico da cristalizacao da bioceramica de dissilicato de litio obtida atraves da silica da casca de arroz

    Energy Technology Data Exchange (ETDEWEB)

    Santos, F.A.; Santos, C.; Pinatti, D.G., E-mail: elipeantunes@usp.br [Universidade de Sao Paulo (EEL/USP), Lorena, SP (Brazil). Escola de Engenharia; Lazar, D.R.R. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Davim, E.; Fernandes, M.H.F.V. [Universidade de Aveiro, Campos Universitario de Santiago, Aveiro (Portugal)

    2011-07-01

    In this work, the study of crystallization of the lithium disilicate glass-ceramic produced for alternative source (rice husk silica), and comparatively by commercial source (commercial silica) it was carried through. The stoichiometry 66%.mol SiO{sub 2}: 33%.mol LiO{sub 2} was used. The kinetic studies of crystallization and calculations had been carried through thermal analysis (DTA), and were possible to study the behavior of the curves in accordance with the variation of taxes (5; 10; 15; e 20°C/min), of the granulometries 63 μm, 250μm and 1mm), and for the influence of the substitution commercial SiO{sub 2} by rice husk. The structural characterization was carried through by X-Ray diffractometry (DRX) and scanning electron microscopy (MEV), for chemical characterization used X-Ray fluorescence (FRX). The preliminary results show that the substitution of the silica source is sufficiently promising, since the gotten properties are similar. (author)

  12. Effect of the method to prepare platinum-based nanoparticles versus electro-reduction of nitrates and proton adsorption; Efecto de la ruta de preparacion de nanoparticulas basadas en platino versus la electro-reduccion de nitratos y la adsorcion de protones

    Energy Technology Data Exchange (ETDEWEB)

    Estudillo-Wong, L.A.; Torres-Santillan, E.; Arce-Estrada, E.M.; J.R. Vargas-Garcia [Escuela Superior de Ingenieria Quimica e Industrias Extractivas (ESIQIE), IPN, Mexico D.F. (Mexico)]. E-mail: amanzor@ipn.mx; Alonso-Vante, N. [Universite de Poitiers, Poitiers (France); Manzo-Robledo, A. [Escuela Superior de Ingenieria Quimica e Industrias Extractivas (ESIQIE), IPN, Mexico D.F. (Mexico)

    2009-09-15

    nitratos indican que la magnitud de corriente de reduccion disminuye y, ademas, presentan magnitudes diferentes en funcion del catalizador/sustrato en turno. Estas variaciones son explicadas en terminos de desordenes locales debidos a la naturaleza del sustrato y al tamano de las nano-particulas dado por el metodo de preparacion. Indirectamente, los parametros cineticos calculados permitieron elucidar dichas suposiciones.

  13. Research and development of hydrogen and fuel cells technology at the IIE; Investigacion y desarrollo de tecnologia de hidrogeno y celdas de combustible en el IIE

    Energy Technology Data Exchange (ETDEWEB)

    Cano C, Ulises; Arriaga H, Gerardo; Romero C, T; Medrano V, M. Consolacion; Gonzalez, A. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2005-07-01

    D relacionados con celdas de combustible iniciaron a partir de estudios basicos electroquimicos de electrodos de platino sobre carbon vitreo en soluciones acidas, para determinar parametros cineticos y propiedades estructurales. Puesto que los principales componentes de las celdas PEM definen en gran medida el costo de la tecnologia, otros esfuerzos adicionales ligados a estudios basicos para el desarrollo de componentes como placas bipolares, estan descritos por el mismo autor en el 2001. Otros trabajos sobre investigacion basica estan ligados a la repuesta de monoceldas de combustible a diferentes condiciones de operacion, y que tambien se revisaran en este articulo.

  14. Parameter calculation tool for the application of radiological dose projection codes; Herramienta de calculo de parametros para la aplicacion de codigos de proyeccion de dosis radiologicas

    Energy Technology Data Exchange (ETDEWEB)

    Galindo G, I. F.; Vergara del C, J. A.; Galvan A, S. J. [Instituto Nacional de Electricidad y Energias Limpias, Reforma 113, Col. Palmira, 62490 Cuernavaca, Morelos (Mexico); Tijerina S, F., E-mail: francisco.tijerina@cfe.gob.mx [CFE, Central Nucleoelectrica Laguna Verde, Carretera Federal Cardel-Nautla Km 42.5, 91476 Municipio Alto Lucero, Veracruz (Mexico)

    2016-09-15

    The use of specialized codes to estimate the radiation dose projection to an emergency postulated event at a nuclear power plant requires that certain plant data be available according to the event being simulated. The calculation of the possible radiological release is the critical activity to carry out the emergency actions. However, not all of the plant data required are obtained directly from the plant but need to be calculated. In this paper we present a computational tool that calculates the plant data required to use the radiological dose estimation codes. The tool provides the required information when there is a gas emergency venting event in the primary containment atmosphere, whether well or dry well and also calculates the time in which the spent fuel pool would be discovered in the event of a leak of water on some of the walls or floor of the pool. The tool developed has mathematical models for the processes involved such as: compressible flow in pipes considering area change and for constant area, taking into account the effects of friction and for the case of the spent fuel pool hydraulic models to calculate the time in which a container is emptied. The models implemented in the tool are validated with data from the literature for simulated cases. The results with the tool are very similar to those of reference. This tool will also be very supportive so that in postulated emergency cases can use the radiological dose estimation codes to adequately and efficiently determine the actions to be taken in a way that affects as little as possible. (Author)

  15. Relación entre la entalpía de inmersión de monolitos de carbon activado y parametros texturales

    Directory of Open Access Journals (Sweden)

    Diana P. Vargas

    2011-01-01

    Full Text Available In this study, Disc and honeycomb-shaped activated carbon monoliths were obtained using as a precursor coconut shell, without the use of any binder. Textural characterization was performed by adsorption of N2 at 77 K and immersion calorimetry into benzene. The experimental results showed that the activation with zinc chloride produces a wide development of micropores, yielding micropore volumes between 0,38 and 0,79 cm³ g-1, apparent BET surface area between 725 and 1523 m² g-1 and immersion enthalpy between 73,5 and 164,2 J g-1.Were made comparisons between textural parameters and energy characteristics.

  16. Physical-chemicals parameters and microbiological indicators in sewage treatment of Ciudad Real; Parametros fisicoquimicos e indicadores microbiologicos en la depuracion de aguas residuales de Ciudad Real

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Solanilla, E.; Ubeda Iranzo, J.F.; Perez Bencecry, C. [E.U.I. Tecnica Agricola. Ciudad Real. Universidad de Castilla-La Mancha (Spain)

    1997-05-01

    The aim of this work is to find out the possible relationship between some physico-chemical (pH, conductivity dissolved oxygen, suspended solids, DBO, DQO) and sanitary microbiological parameters (total coliforms, faecal coliforms, faecal streptococcus , coliphages) in a sewage treatment. It was carried out in a waste water treatment plant with an activated sludges process of conventional design. The most significative effects that primary treatment and the biological treatment on the parameters analyzed were stablished. On the other hand, effective chlorine doses and contact time were determined for a possible reuse of the treated water. (Author) 16 refs.

  17. Monitoreo de parametros físico-químicos en la cuenca alta del río Bogotá

    Directory of Open Access Journals (Sweden)

    Julia Sierra

    2002-01-01

    Full Text Available La Universidad Militar "Nueva Granada" en su constante interés por el desarrollo de nuevas técnicas que permitan la preservación del medio ambiente, inició en el año 2000 la investigación "IDENTIFICACIÓYNPRUEBADEBIOINDICADORESy RECUPERADORES PARALA DESCONTAMINACIÓN DEL RÍO BOGOTÁ". En la primera fase de este estudio se hace un diagnóstico de la situación actual de la cuenca alta del Río Bogotá, a través de los proyectos de grado presentados por los estudiantes de la Universidad y dirigidos por un grupo de profesores. Se realizó una investigación como Tesis de Grado para optar al título de Ingeniero Civil,donde se analiza el comportamiento de los pará-. metros fisico-químicos en la cuenca alta del Río Bogotá; estos parámetros son de gran importancia ya que establecen las modificaciones que sufre una corriente superficial, como consecuencia de los diferentes usos del agua (causados por actividades industriales, domésticas, recreativas y de transporte. El título del trabajo de grado es "MONITOREODE PARÁMETROSFISICO-QUÍMICOS,EN LA CUENCAALTA DEL RÍO BOGOTÁ". Los aspectos fisicos que se tienen en cuenta en este trabajo son: turbiedad, temperatura y conductividad, y como aspectos químicos oxígeno disuelto, demanda bioquímica de oxígeno (DBO, demanda química de oxígeno (DQO, pH, alcalinidad total, acidez, dureza, cIoruros, amonio, nitritos, nitratos, fosfatos altos y bajos, sulfatos, cromo, cobre y cloro total.

  18. Evaluation of parameters associated with monitoring in vivo of uranium isotopes in the lungs; Avaliacao de parametros associados a monitoracao in vivo de isotopos de uranio nos pulmoes

    Energy Technology Data Exchange (ETDEWEB)

    Juppa, Silvia P.; Lucena, Eder A.; Dantas, Bernardo M.; Dantas, Ana Leticia A., E-mail: adantas@ird.gov.br [Instiluto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Laboratorio de Monitoracao In Vivo. Divisao de Dosimetria

    2013-11-01

    The objective of this study is to evaluate the parameters associated with the technique of monitoring individuals exposed to uranium isotopes, aiming to optimize the technique and reduced uncertainties associated.

  19. Comparison of neutron parameters between a CANDU and ACR reactors; Comparacao de parametros neutronicos entre um reator CANDU e um ACR

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Gabriel H.P.; Silva, Clarysson A.M. da; Pereira, Claubia, E-mail: gabrielhpd@yahoo.com.br, E-mail: clarysson@nuclear.ufmg.br, E-mail: claubia@nuclear.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

    2017-11-01

    CANDU (Canadian Deuterium Uranium) is a type of reactor that uses heavy water (D{sub 2}O) as a moderator and as a refrigerant. Despite having chemical characteristics similar to light water (H{sub 2}O), heavy water has a high moderation ratio for neutrons. This feature enables CANDU to use natural uranium as fuel. However, research has evaluated the possibility of using H{sub 2}O as a refrigerant and D{sub 2}O as a moderator aiming at reducing the volume of heavy water. Such changes would imply the use of lightly enriched uranium due to the presence of H{sub 2}O. In this context, the concept of ACR (Advanced CANDU Reactor) has been developed. This reactor has an innovative design which combines of the current CANDU with the characteristics of PWR (Pressurized Water Reactor) type reactors. Studies by AECL (Atomic Energy Canada Limited) show that compared to CANDU, the ACR presents a cost reduction in construction, improved firing performance, improved operation safety and longer life. The present work aims to evaluate, in steady state, some of the main neutron parameters of CANDU-6 and ACR-1000. The MCNPX 2.6.0 code (Monte Carlo N-Particle eXtended -version 2.6.0) was used to simulate such types of reactors. The results show that the models configured in the MCNPX adequately reproduce the neutron behavior of the studied reactors. These models may be used in future work for analysis of fuel burn and evolution.

  20. VARIACION DE PARAMETROS DE CRIPTOGRAFIA CON CURVAS ELIPTICAS USADOS EN LA FIRMA DIGITAL DE DATOS SOBRE UNA RED DE SENSORES INALAMBRICOS

    Directory of Open Access Journals (Sweden)

    Javier Omar Contreras Rodriguez

    2016-09-01

    Full Text Available En la actualidad, el auge de las aplicaciones de las redes de sensores inalámbricos (WSN = Wireless Sensors Networks está generando una gran cantidad de información de carácter sensible que requiere un manejo confiable mediante la implementación de sistemas de seguridad de los datos compatibles con la naturaleza de estas redes. En ese sentido, cada vez más aumenta el interés por el uso de algoritmos de criptografía de clave pública con curvas elípticas (ECC = Elliptic Curve Cryptography como una alternativa de menor consumo de recursos computacionales comparado con los algoritmos tradicionalmente usados, como por ejemplo, RSA (Rivest-Shamir-Adleman, Diffie-Hellman, otros. En este artículo, se revisa la construcción de un prototipo de sistema de seguridad usando ECC para la firma digital de datos (ECDSA = Elliptic Curve Digital Signature Algorithm usando un control lógico basado en redes definidas por software (SDN = Software Defined Networking para el control de funcionalidades básicas y que permita ajustar en tiempo real los parámetros del algoritmo ECDSA según el tipo de aplicación de la WSN.

  1. Study of biogas production parameters in the sanitary landfill; Estudio de los parametros que afectan la produccion de biogas en un vertedero controlado

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez Domenech, G.; Gordillo Bolasell, M. A.; Sanchez Ferrer, A.

    2001-07-01

    The following article contents a study about some of the parameters affecting the evolution of the gas production in a sanitary landfill placed in the province of Barcelona. The work is focused on the quality of biogas produced, measured as the percentage of methane and thus its energy profitability. The parameters included in this paper are: -Situation of the gas extraction station -Age of the wastes. -Reinfiltration of concentrated liquid leachate in the considered cell. Among the previous factors, the situation of the gas station and the age of wastes showed a critical influence on the methane content, whereas the use of leachate reinfiltration did not produce significant differences in the quality of biogas in the short-term applications. (Author) 5 refs.

  2. EFECTO DE DIFERENTES TIEMPOS DE ALMACENAMIENTO EN FRÍO SOBRE ALGUNOS PARAMETROS DE Phytoseiulus persimilis (Athias Henriot Y Neoseiulus californicus (PARASITIFORMES: PHYTOSEIIDAE

    Directory of Open Access Journals (Sweden)

    Adriana De la Peña

    2011-05-01

    Full Text Available Los ácaros depredadores Phytoseiulus persimilis Athias-Henriot y Neoseiulus californicus son controladores importantes de ácaros fitófagos utilizados en programas de producción masiva. El efecto sobre la sobrevivencia, longevidad, capacidad depredadora y fecundidad de estos depredadores fue estudiado después de almacenarlos a una temperatura de 8ºC y humedad relativa de 85+/-5% durante diferentes tiempos (siete, 14, 21, 28 y 35 días y comparado con depredadores no almacenados. Durante el tiempo de evaluación los depredadores fueron individualizados y mantenidos a una temperatura de 25°C y humedad relativa de 85+/-5%. La sobrevivencia, longevidad, capacidad depredadora y fecundidad presentada durante todo el periodo de evaluación de P. persimilis presento una disminución después de ser almacenados por 21 o mas días, al igual que la sobrevivencia y el consumo de presas de N. californicus Sin embargo, la longevidad y oviposición durante todo el periodo de evaluación para N. californicus se afecto después de ser almacenado por 28 o mas días. El consumo diario y fecundidad diaria de ambos depredadores no presentaron efecto con excepción del consumo diario de huevos por P. persimilis y el consumo diario de ninfas por N. californicus después de ser almacenados por 35 días. El efecto sobre el consumo y fecundidad es debido posiblemente al efecto que se presenta sobre la sobrevivencia y longevidad de ambos depredadores.

  3. Therapeutic electrons bunch energy spectrums: correlation among physical parameters and quality; Espectros de energia de feixe de eletrons terapeuticos: correlacao entre parametros fisicos e qualidade

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Rolando Fonseca

    1993-07-01

    A new approach was described for clinical and physical parameters used in radiotherapy planning and dosimetry, studying their dependencies on spectral widths. Two different models of clinical linear accelerators were used-Mevatron 74 (UNICAMP) and Mevatron 12 (HC/FMRP/Ribeirao Preto). Mevatron 74 produces beams with nominal energies from 5 up to 12 MeV and Mevatron 12 from 3 up to 11 MeV. It was verified that the values of clinical parameters expected from a semi-empirical theory differ from that obtained experimentally. Such differences are relevant from the point of view of the design of electron accelerators, as well as, of the target clinical results. (author)

  4. Estimation solar irradiance maps in Extremadura (Spain) by means of meteorological parameters; Mapas de radiacion solar de Extremadura estimada a partir de otros parametros meteorologicos

    Energy Technology Data Exchange (ETDEWEB)

    Ramiro, A.; Nunez, M.; Reyes, J. J.; Gonzalez, J. F.; Sabio, E.; Gonzalez-Garcia, C. M.; Ganan, J.; Roman, S.

    2004-07-01

    In a previous work, we have found correlation expressions that permit to estimate the mean monthly values of daily diffuse and direct solar irradiation on a horizontal surface in function of some weather parameters. In this work, the incident radiation on a horizontal surface has been estimated in thirty zones of Extremadura by means of weather data from existing stations located in these zones and its orography. The weather data used have been the monthly average values of the highest temperatures and the sunshine fraction. These monthly average values have been obtained from measurements carried out in the weather stations during the period 1985-2002. The results are presented as interactive maps in Arc view language, associated to a conventional data base. (Author)

  5. Evaluation of the repeatability of dosimetric parameters of a linear accelerator beam; Avaliacao da repetibilidade de parametros dosimetricos do feixe de um acelerador linear

    Energy Technology Data Exchange (ETDEWEB)

    Morelli, Humberto A.S.; Oliveira, Harley F. de; Silva, Maelson do N.; Pavoni, Juliana F., E-mail: h.morelli@hotmail.com [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Servico de Radioterapia

    2016-07-01

    This study aims to evaluate the repeatability of symmetry and flatness of the photon beam of 6 MV linear accelerator Oncor Impression, Siemens, from the Radiotherapy Department of the Hospital das Clinicas da Faculdade de Medicina de Ribeirao Preto - USP. In total they were collected 102 measures, weekly, through two-dimensional detector of ionization chambers, Matrixx Evolution, IBA Dosimetry, connected to a computer with software OmniProI'mrt. The isocenter of the linear accelerator was placed in the center of the sensitive volume of the detector with solid water plates above and below these. Data were collected with 100 UM, with field size 10 x 10 cm². The flatness and symmetry values were calculated by the software used. The first measurement of this work was used as reference, the others were compared with it, taking into account the values of permissible variation for these parameters. The minimum, maximum and average value were analyzed. The literature indicates that the flatness and symmetry values should not vary by more than 2 and 3%, respectively. The results of this work show that the values of these parameters for the linear accelerator study are within the permissible variations in protocols and are therefore able to appropriate clinical use. (author)

  6. Geometrical parameters effects on a runner-type wind turbine; Efectos de los parametros geometricos para una turbina eolica tipo rueda movil

    Energy Technology Data Exchange (ETDEWEB)

    Loreto, Ramon; Quintero, Freddy; Zambrano, Edgar [Universidad de Los Andes, Merida (Venezuela). Facultad de Ingenieria. Escuela de Mecanica

    1995-07-01

    The project consisted basically on wind tunnel testing of a Runner-Type wind turbine prototype. Testing was aimed at optimizing its performance by varying its geometry. Results are shown which relate geometry and efficiency as compared with Brace Research Institute of Mc Graw-Hill University of Montreal. (author)

  7. Technical and economical parameters of the recovery of straw for six systems; Parametros tecnico-economicos do recolhimento do palhico por seis sistemas

    Energy Technology Data Exchange (ETDEWEB)

    Michelazzo, Marcio Beraldo; Braunbeck, Oscar Antonio [Universidade Estadual de Campinas (FEAGRI/UNICAMP), SP (Brazil). Fac. de Engenharia Agricola], Emails: marcio.michelazzo@agr.unicamp.br, oscar@agr.unicamp.br

    2006-07-01

    An analysis was done of the economic and mechanical parameters involved in the packing processes of the sugarcane trash. A model was defined to estimate the cost of trash recovery simulating the field capacity, oil consumption, depreciation, repair and maintenance as well as labor required for the field and transport operations. Six recovery systems were studied both from the technical and economical points of view. The results showed that handling billets and trash together, described as 'Integral harvesting', has the lowest cost for trash recovery, both for short and long distances, followed by bulk handling of chopped trash, the round bale, the cotton bale and finally the pellet and briquette systems. (author)

  8. Verification of the security analysis including uncertainty in uncertain parameters; Verificacion del Analisis de Seguridad incluyendo la Incertidumbre en Parametros Inciertos

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Magan, J. J.; Fernandez, I.; Gil, J.; Marrao, H.

    2013-07-01

    Work has been applied DAKOTA-SCAIS-MAAP-R for a loss of coolant in the primary sequence analysis, considering parameters and times uncertain, in a 3L-PWR plant Westinghouse design; which allows to verify the security analysis where temporary uncertainty represents an important parameter.

  9. “MEDICION DE PARAMETROS GENERADORES DE ESFUERZOS RESIDUALES DURANTE EL PROCESO DE SOLDADURA DE ACERO INOXIDABLE AUSTENITICO AISI 304L”.

    OpenAIRE

    García López, Christian Jesus

    2012-01-01

    En la actualidad los procesos de soldadura por arco eléctrico se han convertido en la técnica por excelencia para la unión del acero y sus aleaciones. Se puede mencionar que la importancia de la soldadura, es tal, que sin ella no serían posibles muchos de los productos y servicios que cotidianamente son consumidos o requeridos por las sociedades contemporáneas actuales. Cada vez con mayor longitud y diámetro se instalan líneas de tubería para la distribución y conducción de tod...

  10. Evaluación de los Parametros Fisicoquímicos en Reactores Discontinuos de Lodos Activados para el Tratamiento de Aguas con Metanol.

    Directory of Open Access Journals (Sweden)

    Marvin Carabali Lasso

    2017-01-01

    Full Text Available Contexto: en la actualidad existen varios tipos de tecnologías limpias que ayudan a la descontaminación del agua residual industrial, como los sistemas de lodos activados. Dichas tecnologías han resultado efectivas en la remoción de materia orgánica y coloidal en aguas residuales domésticas e industriales, biosorción de metales pesados y remoción de patógenos y nutrientes (N y P. Lo anterior motiva la propuesta de trabajar con un sistema de tratamiento de lodos activados a escala en un ambiente controlado, a fin de demostrar su efectividad en tratamiento de aguas con metanol. Método: el sistema de tratamiento de lodos activados se diseña y construye a escala a nivel de laboratorio para estudiar diferentes concentraciones de metanol en aguas residuales de una industria. En los montajes de cinco sistemas de tratamiento se realizan mediciones de parámetros fisicoquímicos como: pH, oxígeno disuelto, temperatura, demanda química de oxígeno, sólidos suspendidos totales y la pérdida de metanol; a las 0, 24 y 48 h por cuadruplicado para observar el comportamiento de dichos parámetros durante la reducción de metanol. Resultados: para los sistemas de lodos activados se demuestra una pérdida promedio de metanol del 10,3 %. Los promedios de oxígeno disuelto decrecieron en el tiempo, aunque la demanda química de oxígeno es variable. Cada sistema con concentración diferente de metanol presenta comportamiento particular. Conclusiones: esta investigación indica que la biodegradación de metanol en aguas residuales industriales es posible, teniendo en cuenta que en el sistema de tratamiento a escala se obtuvo una disminución de metanol en el tiempo. Además, los resultados motivan a continuar investigando sobre esta tecnología limpia, de la cual no se dispone suficiente literatura en lo que respecta al manejo de lodos activados para la eliminación de metanol.

  11. TIG welding of aluminium foams. Analysis of foaming operating parameters; Soldadura TIG de espumas de aluminio. Analisis de los parametros operacionales de espumado

    Energy Technology Data Exchange (ETDEWEB)

    Portoles, A.; Berenguer, O.; Onoro, J.; Ranninger, C.

    2011-07-01

    In this work the influence of main parameters that take part during TIG welding process are analyzed. Some of these parameters belong to the welding process, as for example the welding speed, intensity and voltage while others are from the material and tooling features, as for example foaming material and tooling design. The result of this work shows a strong dependence on these parameters of the TIG welding process for metallic foams. (Author) 16 refs.

  12. Analisis del signo de Hoover en relacion con parametros funcionales, radiologicos y de radio de curvatura en pacientes con enfermedad pulmonar obstructiva cronica

    Directory of Open Access Journals (Sweden)

    M. E. Capria

    2003-10-01

    Full Text Available El propósito del presente trabajo fue: 1 relacionar el signo de Hoover SH (+ con diversos parámetros funcionales (espirometría y volúmenes pulmonares y radiológicos (radiografías posteroan-teriores, 2 caracterizar los cambios en el radio de curvatura y la eficiencia del diafragma, y restablecer relaciones con los parámetros funcionales y radiológicos. Se estudiaron 15 pacientes con EPOC (SH (+, n: 8. El radio de curvatura fue determinado en el hemidiafragma derecho en inspiración y espiración máximas. Los SH(+ se hallaron más severamente obstruidos (VEF1%, p 0.005% y con mayor atrapamiento aéreo (VR/CPT %, p 0.01. El radio espiratorio (Re fue mayor (p 0.05, y su eficiencia (1/Re, fue menor (p 0.05. El VEF1% correlacionó con el grado de hiperinflación según CPT % (r -0.58, p 0.022 y con el atrapamiento aéreo según VR% (r -0.77, p 0.0008. Los pacientes con menor VEF1% presentaron un Re mayor (r -0. 61, p 0.015 y menor eficiencia diafragmática en espiración (1/Re de acuerdo a: 1/Re = 0.093 cm-1 + 0.0012 cm-1 * VEF1% (r 0.688, p 0.0054. El VEF1 correlacionó con la movilidad diafragmática (r 0.71, p 0.003. La PaCO2 correlacionó con la CPT % (r 0.534, p 0.04, con el VR % (r 0.62, p 0.014 y con los parámetros radiológicos de hiperinflación (r 0.546, p 0.035 y atrapamiento aéreo (r 0.528, p 0.043. El SH(+ sugiere obstrucción bronquial severa, aplanamiento del diafragma, consiguiente aumento del radio de curvatura, menor movilidad y menor eficiencia.The purpose of the present study was: 1 to relate the Hoover sign -SH (+- with several functional (spirometry and lung volumes and radiographic (AP x-ray parameters, 2 to characterize the changes in diaphragmatic curvature radius and the efficiency and to establish some relationships with the functional and radiographic parameters. Fifteen patients with COPD (SH (+, n: 8 were studied. The radius was determined in the right hemidiaphragm after maximal inspired and expired x-ray. The SH (+ was found in more severely obstructed patients (FEV1%, p 0.005% and with high degree of air trapping (RV/ TLC %, p 0.01. The expiratory radius (Re was higher (p 0.05, and their efficiency (1/ Re, was minor (p 0.05. The FEV1% correlated with the degree of hyperinflation according to TLC% (r -0.58, p 0.022 and with air trapping according to RV % (r -0.77, p 0.0008. The patients with low FEV1% showed high Re (r- 0.61, p 0.015 and decreased diaphragmatic efficiency during expiration (1/ Re according to 1/Re = 0.093 cm-1 + 0.0012 cm-1 * FEV1% (r 0.688, p 0.0054. The FEV1 correlated with the diaphragmatic movement (r 0.71, p 0.003. The PaCO2 correlated with the TLC % (r 0.534, p 0.04, the RV% (r 0.62, p 0.014 and with the radiographic parameters of hyperinflation (r 0.546, p 0.035 and air trapping (r 0.528, p 0.043. The presence of Hoover sign suggest severe bronchial obstruction, diaphragmatic flattening, increase of curvature radius, decrease of mobility and efficiency.

  13. Gamma radiation in some microbiological and biochemical parameters of ethanolic fermentation.; Efeito da radiacao gama em alguns parametros microbiologicos e bioquimicos da fermentacao alcoolica

    Energy Technology Data Exchange (ETDEWEB)

    Alcarde, Andre Ricardo

    2000-07-01

    The objective of this work was to evaluate the effect of gamma radiation in reducing the bacterial population of the sugar cane must and verify its influence in the ethanolic fermentation. For this purpose, some microbiological and biochemical parameters of the ethanolic fermentation were analyzed, such as bacterial count; viability, replication and living replicates of the yeast; p H, acidity (total and volatile), glycerol and production of organic acids (acetic, lactic and succinic) during the fermentation; and fermentative yield. Bacteria of the genera Bacillus and Lactobacillus are the most common contaminants of the ethanolic fermentation and they might cause a decrease in the fermentative yield. The ionizing radiations may affect the microorganisms altering the DNA of the cells, which lose the ability to reproduce themselves and die. The experimental design was in randomized blocks (three) with one replicate in each block. The must was sugar-cane juice with approximately 5% of total reducing sugar. Bacteria of the following species were tested: Bacillus subtilis, Bacillus coagulans, Lactobacillus plantarum and Lactobacillus fermentum. The experiments were the inoculation of each bacteria separately in the must, the inoculation of the mixture of the four bacteria in the must and the use of natural sugar-cane juice with its own contaminating microorganisms. The contaminated must was irradiated with the doses of 0.0 (control), 2.0,4.0, 6.0, 8.0 and 10.0 kGy of gamma radiation (60-Cobalt) at an average rate of 2.0 kGy/h. After the irradiation, the fermentation of the must was carried out using the yeast Saccharomyces cerevisiae (Fleischmann). It was also accomplished an experiment with the inoculation of the mixture of the four bacteria in the must and, instead of using gamma radiation to decontaminate the must, it was used the antimicrobial Kamoran ID in the concentration of 3 ppm. The effects of the irradiation of the must were: reduction of the bacterial population that contaminated the must decrease of the total acidity, the volatile acidity, the p H drop and the production of the organic acids (acetic, lactic and succinic) during the fermentation; increased of the viability, the replication and the percentage of living replicates of the yeast after fermentation; and increased of the fermentative yield. The treatment of the sugar-cane must with gamma radiation reduced its bacterial population, with consequent improved of the microbiological and biochemical parameters of the ethanolic fermentation, including the fermentative yield. The irradiation of the must was a better treatment than the use of the antimicrobial Kamoran ID in the fermentation because the yeast in the experiment with the antimicrobial presented smaller viability, replication and percentage of living replicates than in the experiment with the irradiated must. (author)

  14. Characteristic parameters analysis on diagnostic X-ray beams for dosemeter calibration; Analise de parametros caracteristicos de feixes de raios-X diagnostico para calibracao de dosimetros

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Paulo Marcio Campos de

    2008-07-01

    Ionizing radiation metrology is the base to achieve reliable dose measurements in ali areas; it is also part of the framework that is established to assure radiation protection procedures in order to avoid or minimize the harmful biological effect that may be caused by ionizing radiation. A well done metrology means the use of reliable instruments that comply with standard performance requirements worldwide accepted. Those instruments are expected to be calibrated by Metrology Laboratories under well defined conditions. The International Electrotechnical Commission (IEC) in Standard 61267 established the reference radiations for medical diagnostic x-ray equipment that are recommended to be used for calibrating dosimetric systems for diagnostic dosimetry. In this work, X-ray beam qualities were established in a Calibration Laboratory and their characteristics were analyzed through the measurement of beam parameters like inherent tube filtration, beam uniformity and field size, energy spectra and peak voltage for additional filtration with 94.425 por cent and 99.999 por cent purity filters. Also, the first half-value layer and the homogeneity coefficient were measured for the three RQR 2, RQR 6 and RQR 10 IEC beam qualities and they were analyzed according to the IEC standard. Air-kerma measurements were carried out with an ionization chamber that had its reliability confirmed through repetition and reproducibility reading tests. In 50 sets of measurements the maximum standard deviation found of 10 successive readings was 0.19 %; the maximum shift of the reading mean value at a fixed geometry condition was 0.80 % with an overall standard deviation of 0.23 %. Results showed that the use of different purity filters did not cause a relevant influence on the beam energy spectra. An ionization chamber was also calibrated against a standard dosimeter in ali implemented reference radiations and the relevant sources of uncertainties were estimated. Calibration could be done with an expanded uncertainty of 1.50% for a coverage factor of 2 at a 95.45 % confidence level, mainly due to the uncertainty of 0.58% caused by the positioning set-up of the ionization chamber. (author)

  15. Influence of operating parameters in the gravity segregation during the process of steam flood; Influencia dos parametros operacionais na segregacao gravitacional durante a injecao de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Marcos Allyson F.; Galvao, Edney Rafael Viana P.; Barbosa, Janaina Medeiros D.; Barillas, Jennys Lourdes M.; Mata, Wilson da; Dutra Junior, Tarcilio V. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2008-07-01

    Steam injection is the most used method of additional recovery for the extraction of heavy oil. In this type procedure is common to happen gravitational segregation and this phenomenon can affect the production of oil and therefore, it should be considered in the projects of continuous steam injection. The effect of gravity causes the segregation of fluids inside the porous media according to their densities. We know that the gravitational segregation can happen in almost every case where there is injection of light fluid, specially steam, and occurs with greater intensity for viscous oil reservoirs. This work discusses an optimization of some operational parameters as flow rate steam, distance between the wells (injector-producer), and interval of completion, which contributed to the reduction of gravity override, in a numerical model that shows the phenomenon with greater intensity. It was made an analysis of technical and economical viability of an optimized model. The analysis was performed using the simulator of CMG (Computer Modeling Group) - Stars 2007.11, in which it was observed the influence of operational parameters in heavy oil reservoirs with similar characteristics to Brazilian Northeast. (author)

  16. Morphology and parameters of crystallization the blend PE/Epoxy/PE-co-PEG; Morfologia e parametros de cristalizacao da blenda PE/epoxi/PE-co-PEG

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Daniela; Coelho, Luiz Antonio Ferreira; Nack, Fernanda; Silva, Bruna Louise, E-mail: dep2db@joinville.udesc.br [Universidade do Estado de Santa Catarina (UDESC), Joinville, SC (Brazil). Centro de Ciencias Tecnologicas

    2014-07-01

    This study aims to evaluate the morphology and crystallization parameters of high density polyethylene (HDPE) with different concentrations of epoxy (DGEBA / OTBG), and the compatibility of this system was used and the copolymer polyethylene-block-poly (ethylene glycol) (PEG-co-PE). The blends were obtained by mechanical mixing on a torque rheometer (Haake). Determined the crystallization parameters of the test matrix differential scanning calorimetry (DSC) and by X-ray diffraction (XRD). The morphology of the system was analyzed by transmission electron microscopy (TEM). It was observed by XRD analysis that the addition of compatibilizer and epoxy resins do not interfere with the crystal structure of HDPE, indicating that the increase in crystallinity associated with the crystallization kinetics. It was observed that the compatibilizing helped the adhesion, reducing the size of the dispersed phase becomes a more stable morphology and obtaining a distribution of the dispersed epoxy phase. (author)

  17. Influence of laser design parameters on the hydrodynamics of microfusion plasmas; Influencia de los parametros basicos del laser sobre la hidrodinamica de plasmas para microfusion

    Energy Technology Data Exchange (ETDEWEB)

    Sanmartin, J A; Barrero, A

    1976-07-01

    The quasi neutral, one dimensional motion generated in a cold, infinite, uniform plasma of density n{sub 0}, by the absorption, In a given plane, of a linear pulse of energy per unit time and area {phi} - {phi}{sub 0}t/{tau}, 0< t {<=} {tau}, is considered; the analysis allows for thermal conduction and viscosity of ions and electrons, their energy exchange, and an electron thermal flux limiter. The motion is found to be self similar and governed by single non dimensional parameter {alpha} similar{sub t}o(n{sup 2}{sub 0} {tau}/{phi}{sub 0}){sup 2}/3. Detailed asymptotic results are obtained for both {alpha}<<1and {alpha}>>1; the general (behaviour of the solution for arbitrary {alpha} is discussed. The analysis can be easily extended to the case of a plasma initially occupying a half-space, and throws light on the hydrodynamics of laser fusion plasmas. (Author) 51 refs.

  18. The establishment of new control parameters in the aerobic stabilisation of sludge; Establecimiento de nuevos parametros de control en la estabilizacion aerobia de lodos

    Energy Technology Data Exchange (ETDEWEB)

    Barragan Sanchez, J.; Coello Oviedo, M. D.; Cruz Romero, F. J.; Quiroga Alonso, J. M.

    2002-07-01

    This article presents the results obtained in an aerobic sludge digestion process in a conventional waste water treatment plant employing the usual parameters in this type of study as discussed in the literature. The physicochemical parameters used were pH dissolved oxygen, temperature. Chemical Demand for Oxygen (DOQ) total solids (TS) and volatile solids (VS), while the microbiological parameters were fecal coliforms Escherichia coli (EC) and the active and total bacteria counts. The enzymatic parameters examined were the specific oxygen uptake rate (SOUR). In dehydrogenase (DHA) activity and esterase activity (EA). The results obtained permit the conclusions that although physicochemical parameters provide information on the system's performance, they are neither indicative of the degree of endogenesis attained nor representative of the factors affecting the process. The microbiological parameters, on the other hand, are valid as measurements of the evolution of the populations and of the factors affecting them, but are not representative of the endogenous breathing process. besides which they also present problems of quantification. Finally, the enzymatic parameters, dehydrogenase activity and, especially, the DHA/EA ratio, are an efficient tool. Since they are representative of the metabolic state of the sludge, it is possible to establish criteria regarding its stability in relation to the mixed feed sludge. (Author) 11 refs.

  19. Obtention of the parameters of the Voigt function using the least square fit method; Obtencion de los parametros de la funcion Voigt empleando el metodo de minimos cuadrados

    Energy Technology Data Exchange (ETDEWEB)

    Flores Ll, H.; Cabral P, A.; Jimenez D, H

    1990-01-15

    The fundamental parameters of the Voigt function are determined: lorentzian wide ({gamma}{sub L}) and gaussian wide ({gamma}{sub G}) with an error for almost all the cases inferior to 1% in the intervals 0.01 {<=} {gamma}{sub L} / {gamma}{sub G} {<=}1 and 0.3 {<=} {gamma}{sub G} / {gamma}{sub L} {<=}1. This is achieved using the least square fit method with an algebraic function, being obtained a simple method to obtain the fundamental parameters of the Voigt function used in many spectroscopies. (Author)

  20. Designing a reverse osmosis desalination plant, main parameters and compounds; Diseno de una planta desilinizadora de osmosis inversa, parametros y componentes principales

    Energy Technology Data Exchange (ETDEWEB)

    Arango Mesa, H. [Universidad del Valle. Cali. Colombia (Colombia); Gomez Gotor, A. [Universidad de las Palmas de Gran Canaria (Spain)

    1998-12-31

    This paper comments on some of the design features which should be taken into account in planning a reverse osmosis sea water desalination plant. It also examine the components of some of the plant`s main units, such as the high pressure pumping unit and energy recovering system and the types of membrane modules and their use. Finally, it compares that most common commercially available products. (Author) 6 refs.

  1. Evolution of biochemical parameters in irradiated fishes: Serum proteins and intestinal nucleic acids; Evolucion de parametros bioquimicos en peces irradiados: Proteinas en suero y acidos nucleicos en intestino

    Energy Technology Data Exchange (ETDEWEB)

    Garces, F; Andres, P; Davila, C A

    1976-07-01

    In sublethal gamma-irradiated C. auratus, a sudden decrease of total serum protein concentration and a preferential descent of the low molecular weight gamma-globulin fraction have been observed. These effects are transient and after different latent periods dependent on doses, normal values are recovered, A temporal failure of a vascular permeability regulation system is probably implied. The DMA depolymerization. observed in the intestine indicates the action of radio-induced DNA degradation mechanisms since this effect is independent on doses. (Author) 29 refs.

  2. MHD for fusion: parameters bridge between CFD tools and system codes; MHD para fusion: parametros puente entre herramientas CFD y codigos de sistema

    Energy Technology Data Exchange (ETDEWEB)

    Batet, L.; Mas de les Valls, E.; Sedano, L. A.

    2012-07-01

    In the context of regenerating sheaths for fusion reactors, the CFD simulations of liquid metal channels (ML) are essential to know the phenomenology and obtain relevant information for design as: ML thermal gain, to know the thermal efficiency of the component, existence of hot spots, to define the materials to use, existence of flow inversion, etc. Apart from design parameters there are others, bridge parameter, required as inputs into system code. In this work shown GREENER/T4F capabilities for obtaining both parameters with a CFD tool based on open source OpenFOAM.

  3. Control system and environmental parameters monitoring of the Tandetron Accelerator clean room; Sistema de control y monitoreo de parametros ambientales del cuarto limpio del acelerador Tandetron

    Energy Technology Data Exchange (ETDEWEB)

    Mejia V, M.E.; Garcia H, J.M.; Flores M, J. [ININ, Departamento de Sistemas Electronicos, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: mmejia@nuclear.inin.mx

    2007-07-01

    A control system and monitoring of humidity and temperature implemented by means of a system based on a microcontroller, an intelligent sensor and a stage of power for the actuators handling is described. The change of the levels of reference of the control system and the monitoring of the physical controlled variables can be carried out from any connected computer to a local net or Internet. (Author)

  4. Source and ground-motion parameters of the 2011 Lorca earthquake; Parametros de la fuente y del movimiento del suelo del terremoto de Lorca de 2011

    Energy Technology Data Exchange (ETDEWEB)

    Alguacil de la Blanca, G.; Vidal Sanchez, F.; Stich, D.; Mancilla Perez, F. L.; Lopez Comino, J. A.; Morales Soto, J.; Navarro Bernal, M.

    2012-07-01

    113 events of the Lorca seismic series has been relocated by using Double difference algorithm and data from both temporary and permanent seismic networks. Relocations yield shallow hypo central distribution of aftershocks with a {approx}5 km long, NE-SW trending, placed SW of the mainshock, suggesting a SW propagating rupture along the Alhama de Murcia fault. Similar oblique reverse faulting mechanism has been obtained for three largest events. Source parameters of these three earthquakes have been estimated. Horizontal ground motion was estimated at 11 city points whose local structure was known by SPAC experiments. A set of ground motion parameters (PGA, PGV, AI, CAV, SI, SA and SV) here calculated, have higher values at these points respect to the ones at LOR station. All parameter values are also above the expected values for Euro -Mediterranean earthquakes with local intensity VIII (EMS). Nevertheless, SD values are unusually short and less than the reference ones. Higher values of the response spectra of acceleration and velocity are given for periods of less than 0.7 s, with maximum spectral acceleration at 0.15 s and velocity at 0.5 s. The elastic input energy spectrum is well connected to the shake destructiveness in each place. Equivalent velocity > 60 cm/s is found in almost all sites and > 100 cm/s (for periods 0.3 to 0.6 s) in someone. Factors such as proximity, and focal mechanism and ground response characteristics explain the high ground motion parameter values obtained in Lorca sites and show the great influence of the source and site conditions on the characteristics of strong ground motion in the vicinity of the rupture. (Author) 68 refs.

  5. Prototype for the measurement of parameters in the Mammography Unity using photodiodes; Prototipo para la medicion de parametros en una Unidad de Mamografia utilizando fotodiodos

    Energy Technology Data Exchange (ETDEWEB)

    Mercado H, I.; Ramirez J, F.J.; Tovar M, V.; Becerril V, A. [Instituto Nacional de Investigaciones Nucleares, Salazar, Estado de Mexico C.P. 52045 (Mexico)

    1999-07-01

    It has been developed a prototype which makes possible to measure the kilo voltage applied to the X-ray tube, the exposure time of the radiation beam and the yield expressed in kerma in air K a (mGy/m As) o a mammography unit. The instrument consists of a radiation detector, an acquisition circuit, a stage of analogical processing of the signal connected to an analogic-digital converter and a display system of the results. The detection section is composed by a pair of photodiodes PIN type in which to do make the measurement of kilo voltage one of them is covered by an aluminium filter (Al) and the other one by a molybdenum filter (Mo). The measurements were done in a mammography unit which possess a generator of high frequency, with a molybdenum anode, a window 8 mm Beryllium (Be) and an additional filtration of 30 {mu} m Mo. The measurements obtained were compared with commercial instruments finding maximum variations of 2 % of value obtained. This prototype has been developed with the idea to obtain in a future a commercial instrument, for be used mainly in the hospitable institutions as an auxiliary tool in the Quality assurance programs in radiodiagnostic. (Author)

  6. Characterization of an erbium doped fiber amplifier starting from its experimental parameters; Caracterizacion de un amplificador de fibra dopada con erbio a partir de sus parametros experimentales

    Energy Technology Data Exchange (ETDEWEB)

    Bello J, M.; Kuzin, E.A.; Ibarra E, B. [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Luis Enrique Erro No. 1, TonantzintIa, 72000 Puebla (Mexico); Tellez G, R. [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas No 152, Delegacion Gustavo A. Madero, 07730 Mexico D.F. (Mexico)]. e-mail: mabello@inaoep.mx

    2007-07-01

    In this paper we describe a method to characterize the gain of an erbium-doped fiber amplifier (EDFA) through the numerical simulation of the signal beam along the amplifier. The simulation is based on a model constituted by the propagation and rate equations for an erbium-doped fiber. The manipulation of these equations allows us to regroup the parameters present in an EDFA, which we have named the A, B, C, D parameters, and they can be obtained experimentally from an erbium-doped fiber. Experimental results show that the measurement of these parameters allow us to estimate with very good correspondence the amplifier gain. (Author)

  7. Blood culture as a parameter of treatment effectiveness in experimental histoplasmosis of the hamster Hemocultivos como parametro de la eficacia del tratamiento de la histoplasmosis experimental en hamster

    Directory of Open Access Journals (Sweden)

    J. Finquelievich

    1995-04-01

    Full Text Available The aim of this study was to determine the value of blood culture as a parameter of treatment effectiveness in experimental histoplasmosis. A total of thirty five hamsters, weighing approximately 120g, were inoculated intracardiacly with 0.1 ml of a suspension containing 4 x 10(7 cells/ml of the yeast phase of H. capsulatum. Treatments were started one week after the infection and lasted for 3 weeks. The azoles, (itraconazole, saperconazole and fluconazole were administered once a day by gavage, at a dose of 8 mg/kg; Amphotericin B was given intraperitonealy every other day at a dose of 6mg/kg. Blood samples (1 ml were obtained by heart punction from the 4th day after infection and were seeded in Sabouraud honey-agar and BHI-agar. The hamsters that survived were killed one week after treatment completion and the following criteria were considered for treatment evaluation: 1 rate of spontaneous death, at the end of the experience; 2 microscopic examination of Giemsa smears from liver and spleen and 3 determination of CFU in spleen cultures. Amphotericin B was the most effective drug, with negative blood cultures at day 20, negative spleen cultures in all cases and all the animals survived until the end of the study. Fluconazole was the less effective drug, blood cultures were positive during the whole experience, spleen cultures showed a similar average of CFU when compared with the control animals and 42.8% of these animals died. Saperconazole and itraconazole showed a similar activity, with survival of all hamsters and negative blood cultures at 23 and 26 days respectively. Blood culture seems to be valuable parameter for treatments' evaluation in experimental histoplasmosis of the hamster.El propósito de esta investigación fue determinar el valor de los hemocultivos para juzgar la eficacia de los tratamientos en la histoplasmosis experimental. Treinta y cinco hamsters fueron inoculados por via intracardíaca con 0.1 ml de una suspensión de la fase levaduriforme del H. capsulatum equivalente a 4 x 10(7 células/ml. Los tratamientos comenzaron 1 semana después de la infección y se mantuvieron durante 3 semanas. Los compuestos azólicos, itraconazol, saperconazol y fluconazol se administraron por gastroclisis, una vez al día, a razón de 8mg/kg de peso; la anfotericina B fue aplicada por via intraperitoneal día por medio, en dosis de 6mg/kg. Se obtuvieron muestras de sangre para hemocultivo (1 ml a partir del 4º día post-infección y se sembraron placas de agar-miel de Sabouraud y agar infusión de cerebro y corazón. Los animales que sobrevivieron fueron autopsiados y se tomaron en consideración los siguientes parámetros: 1 tasa de muertes espontáneas al finalizar la experiencia; 2 resultados de los exámenes microscópicos de extendidos de hígado y bazo teñidos com Giemsa y; 3 UFC en cultivos de bazo. La anfotericina B fue la droga más eficaz, los hemocultivos de los animales tratados fueron negativos a partir del 20º dia de tratamiento, se negativizaron los cultivos de bazo y la totalidad de los hamsters sobrevivió. El menos eficaz fue el fluconazol que no modificó los resultados de los hemocultivos y los cultivos esplénicos y se registró el 42.8% de muertes espontáneas durante el estudio. Saperconazol e itraconazol exhibieron una eficacia similar, no se observaron muertes en los animales tratados y los hemocultivos se negativizaron a los 23 y 26 dias de tratamiento respectivamente. Los hemocultivos resultaron ser útiles como criterio para evaluar la eficacia terapéutica de las drogas antifúngicas en este modelo experimental de histoplasmosis.

  8. Effect of the empty fraction in a solar reactor of fluidized bed; Efecto de la fraccion vacia en un reactor solar de lecho fluidizado

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Alejandro; Romero-Paredes, Hernando; Vazquez, Alejandro; Torijano, Eugenio; Ambriz, Juan J [Universidad Autonoma Metropilitana-Iztapalapa, Mexico, D.F. (Mexico)

    2000-07-01

    de lecho fluidizado que a la vez sirve como receptor solar de un sistema de almacenamiento termoquimico de la energia solar. Los complejos fenomenos que se tienen en estos reactores hacen dificil su dimensionamiento para su aplicacion solar. Por ello, modelar y simular su comportamiento sin y con reaccion quimica ayuda a paliar este inconveniente. Uno de los fenomenos presentes es el cambio de la fraccion vacia en la cual concentramos nuestra atencion. En este trabajo se propone una alternativa en el modelado de estos sistemas considerando las fluctuaciones locales de la fraccion vacia o porosidad {epsilon}(x, y) en el lecho. Para esto se propone una distribucion probabilistica uniforme para todos los nodos de la malla (x, y) del lecho donde se asocian valores de porosidad locales para cada nodo de la malla mediante un generador aleatorio donde {epsilon}(x, y){epsilon} [0.1]. La fraccion nueva juega un papel muy importante debido a que la penetracion de la radiacion solar en estos sistemas de cuerpos opacos depende directamente de la distribucion de espacios vacios en la trayectoria de la radiacion incidente que afecta su comportamiento termico y cinetico. De los resultados se puede comprobar la caracteristica de no isotermicidad del reactor lo que conlleva, una vez alcanzada la temperatura de reaccion, a un perfil de concentraciones disperso. La fraccion vacia es un parametro que influye grandemente en estos perfiles y que incrementando el numero de fluidizacion es como se logra disminuir ese tiempo. En conclusion, se resalta la importancia que juega la fraccion vacia en la evolucion tanto de los perfiles de temperatura como de concentracion. El comportamiento del lecho en la simulacion se hace mas precisa de acuerdo con los resultados experimentales previamente obtenidos.

  9. Kinetic study and application of analytical techniques in the obtention of TeO{sub 2} for the production of {sup 131} I; Estudio cinetico y aplicacion de tecnicas analiticas en la obtencion de TeO{sub 2} para la produccion de {sup 131} I

    Energy Technology Data Exchange (ETDEWEB)

    Plata D, G

    2006-07-01

    The objectives of this investigation work were: A) To synthesize TeO{sub 2} starting from the reaction among the Te and HNO{sub 3} with a superior yield to 90% b) To determine the good temperature of obtaining of the TeO{sub 2} at laboratory level, c) To determine those constant of reaction kinetics, for each one of the tests carried out to different temperatures, and the activation energy of the reaction, d) To characterize the produced TeO{sub 2}, e) To check the viability of using the obtained TeO{sub 2} as raw matter in the production of {sup 131} I in order to contribute to the technological development of our country inside the radioisotope production area. The production process of TeO{sub 2} consists primarily of seven phases: 1) Preparing and assembly of the production equipment of TeO{sub 2}, 2) Oxidation reaction of tellurium, 3) Drying and elimination of sludges of TeO{sub 2}, 4) Sintering of TeO{sub 2}, 5) Characterization of the TeO{sub 2} by means of analytical techniques, 6) Irradiation of the TeO{sub 2}, 7) Quality control. The present document has five chapters, which allow the reader to follow the development of this work to achieve the objectives and to contrast with the hypothesis of the work. (Author)

  10. A contribution to the kinetic study of the metatectic reaction U+U{sub 3}Si{sub 2}{yields}U{sub 3}Si; Contribucion al Estudio cinetico de la Reaccion Metatectica U+U{sub 3}Si{sub 2} U{sub 3}Si

    Energy Technology Data Exchange (ETDEWEB)

    Arroyo Ruiperez, J; Esteban Hernandez, J A

    1962-07-01

    An experimental study has been made to decide upon the advantages and drawbacks of the different methods and reagents employed in the metallography of U-Si alloys. It has been observed that all samples thermally treated to form the epsilon-phase undergo from the beginning a coalescence of the U{sub 3}Si{sub 2} particles, which makes practically useless any fine state of dispersion that might be present originally, as recommended by some authors. The coalescence of the U{sub 3}Si{sub 2} particle decreases the surface available for reaction and consequently the reaction rate. (Author) 7 refs.

  11. Radiomimeticity of the system H{sub 2}O{sub 2}/Fe(II) on nucleic acid components. Kinetics study; Radiomimeticidad del sistema H{sub 2}O{sub 2}/Fe(II) sobre components de Acidos Nucleicos. Estudio Cinetico

    Energy Technology Data Exchange (ETDEWEB)

    Cirauqui, R; Mingot, F; Davila, C A

    1974-07-01

    The kinetic study of the action of a redox system on DNA monomers allowed us to make criticisms on radiomimetic character of this system. Assuming that in both cases, gamma radiolysis of aerated aqueous solutions and action of H{sub 2}O{sub 2} / Fe(II) system in the same conditions, the reactive species is the OH radical, we propose the kinetic expressions that are confirmed by our experimental results. Some of the accepted G-values are corrected in view of our results. Al so these results put in evidence mechanisms of molecular repair after radical attack. (Author) 79 refs.

  12. Analysis of Soil Parameters in Almadenejos. Behavior of Mercury in Soil-Plant System; Analisis de Parametros Edaficos en Almadenejos. Comportamiento del Mercurio en el Sistema Suelo-Planta

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, R; Sierra, M J; Villadoniga, M; Millan, R

    2010-03-03

    This scientific-technical report is the result of the stay of Rocio Fernandez Flores practices in the Research Unit soil degradation of the Department of Environment CIEMAT. The aim of this study is to determine the behaviour of mercury in soil of Almadenejos (Almaden, Ciudad Real, Espana) by using a six-step sequential extraction procedure and evaluate the transfer of this pollutant to Marrubium vulgare L., predominant in the area and studied for years due to its ability to accumulate large amounts of mercury without visual symptoms of toxicity. Furthermore, the results will be useful in order to determine if this plant specie could be used as phyto extractor in the recovery mercury contaminated soils. The results show that total mercury concentrations in soil ranged from 709 mg kg-1 to 22,616 mg kg-1. Regarding mercury distribution among different soil fractions, this heavy metal is mainly found in the fraction assigned in the fi nal insoluble residues, the oxidizable fraction and in the crystalline Fe-Mn oxydroxides, on the other hand, barely 1% or lower is readily available to plants However, Marrubium vulgare is able to accumulate high amount of mercury (3.5 - 373.5 mg kg-1). Regarding the mercury distribution inside the plant, mercury concentration in the root was higher than in the aerial part. Within the aerial part the maximum mercury concentration was generally found in leaves. According to the obtained results, Marrubium vulgare L. could be considered as a (hyper)accumulator plant. (Author) 57 refs.

  13. Optimization of the technical parameters of a module for slow pasteurization of milk and cheese production; Otimizacao dos parametros termicos de um modulo para pasteurizacao lenta do leite e fabricacao de queijos

    Energy Technology Data Exchange (ETDEWEB)

    Azevedo Passos, M.L. de; Bemquerer, A; Coelho, S V [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Escola de Engenharia

    1985-12-31

    In this work a methodology for the dimensioning of a module for slow pasteurization of milk with view to a subsequent cheese fabrication is presented. The ultimate purpose of the module is small-scale making of cheese. The equipment consist of: a rectangular tank with a water jacket for hot and cold water, batch operated and thermally insulated; a furnace with a coil for circulating water, fueled by wood, rice hulks and other agricultural refuse. Based on a theoretical analysis a initial model is a developed for athermal optimization of the module. Its dimensions are specified by the quantity of milk to be handled, the form of heating and the available flow of cold water. By building a test unit the first experimental data have been obtained to make a viable use of the initial model. (author). 6 refs., 3 figs., 1 tab

  14. Separation of oily materials in radioactive waste waters by flotation. Determination of operation and control parameters; Separacion de materiales oleosos en aguas residuales radiactivas por flotacion. Determinacion de parametros de operacion y control

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz O, H B; Flores E, R M [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2003-07-01

    In this work the determination of the operation and control parameters (air/solids ratio G/S, retention time {theta}, pressure P and de pressurized volume of mixed air-water V), of the flotation system used in the treatment of oleaginous residual water (polluted mainly with {sup 60} Co) coming from the decontamination process of worn out oils, using as response parameters the concentration of oleaginous material and the residual turbidity. The obtained results allowed to observe the dependence of G/S with the pressure and volume of air-water given. At the same time it was settled down that the set of operation conditions that offers the greater separation percentage of G As and turbidity in the smallest time, they are those obtained by V{sub 2} = 0.0012 m{sup 3} and P{sub 2} = 620 kPa, (G/S = 0.30 - 0.35, = 14-16 min) for what were employees as the ideal values of operation and control in the flotation system. As long as, the concentration of total Co is found under 1 mgL{sup -1}. Finally, the selected flotation system showed high separation levels of {sup 60} Co, whose specific activity are below of 0.007 BqmL{sup -1}. (Author)

  15. Parameter estimation of stable models and with minimum phase in dynamic aggregation of voltage regulators; Estimacao de parametros de modelos estaveis e de fase minima na agregacao dinamica de reguladores de tensao

    Energy Technology Data Exchange (ETDEWEB)

    Souza, E.J.S. Pires de [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Eletrica], E-mail: pires@ele.puc-rio.br

    2009-07-01

    The dynamic aggregation of coherent generating unit models has been solved as an unconstrained optimization problem. In this process, negative time constants may be obtained, which characterize unstable or non-minimal phase models. The comparison of the solutions of the dynamic aggregation problem of voltage regulator models obtained with both the original formulation and the squared-variable transformation is the objective of this paper. Initial values are within the range from +100% to -90% in relation to the estimated parameters. The New England system including models of the Brazilian system is considered in the studies. (author)

  16. Thermodynamics analysis of an autonomous distillery operating with high steam parameters and two different distillation technologies; Analise termodinamica de uma destilaria autonoma operando com altos parametros de vapor e duas tecnologias diferentes de destilacao

    Energy Technology Data Exchange (ETDEWEB)

    Palacio, Jose Carlos Escobar; Lora, Electo Eduardo Silva; Venturini, Osvaldo Jose; Santos, Jose Joaquim [Universidade Federal de Itajuba (NEST/UNIFEI), MG (Brazil). Nucleo de Excelencia em Geracao Termeletrica e Distribuida; Moura, Adler [DEDINI Industrias de Base S.A., Piracicaba, SP (Brazil)

    2008-07-01

    The objective of this paper is to carry-out an integrated thermodynamic analysis for an ethanol distillery and the mill cogeneration plant. In previous works the cogeneration system has been analyzed separately using thermoeconomic tools to calculate the products cost and to define the best scheme and parametric alternative. Similar researches were carried-out aiming to reduce the energy consumption in the distillation process. This paper proposes a simultaneous evaluation of both systems using an exergoeconomic tools to improve the energy integration of process. (author)

  17. Impregnation of 12-tungstophosphoric acid on silica - part I: determination of impregnation parameters, characterization and evaluation of catalytic activity; Impregnacao do acido 12-fosfotungstico em silica - parte I: determinacao de parametros de impregnacao, caracterizacao e avaliacao da atividade catalitica

    Energy Technology Data Exchange (ETDEWEB)

    Scroccaro, Karine Isabel; Tanobe, Valcineide Oliveira de Andrade; Cocco, Lilian Cristina; Yamamoto, Carlos Itsuo, E-mail: karineisabel@yahoo.com.br [Universidade Federal do Parana, Curitiba, PR (Brazil). Centro Politecnico. Dept. de Engenharia Quimica; Wypych, Fernando [Universidade Federal do Parana, Curitiba, PR (Brazil). Centro Politecnico. Dept. de Quimica

    2012-07-01

    Catalyst based on Kegging-type heteropolyacids (H{sub 3}PW{sub 12}O{sub 40} - HPA), supported on SiO{sub 2} (H{sub 3}PW), were prepared by the impregnation method under different thermal treatment conditions. The materials were characterized by different instrumental techniques and used as catalysts in the methyl esterification reactions of stearic acid. Using the catalyst with 15% of HPA, conversions higher than 60% were obtained after 2 h of reaction at 65 deg C. Recovery studies using hot-filtration with ethanol at 75 deg C showed satisfactory activity for two additional reaction cycles. (author)

  18. Evaluation of the influence of parameters that determine the mean glandular dose in mammography using different detectors; Evaluacion de la influencia de los parametros que determinan la dosis glandular media en Mamografia utilizando diferentes detectores

    Energy Technology Data Exchange (ETDEWEB)

    Costa, K.; Nogueira, M. S., E-mail: katicostabh@gmail.com [Centro de Desenvolvimento da Tecnologia Nuclear, Pos-graduacao em Ciencias e Tecnologia das Radiacoes, Minerais e Materiais / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil)

    2015-10-15

    Full text: Mammography is a test used for early detection of breast cancer. The mean glandular dose (MGD) is dosimetric greatness accepted as indicative of carcinogenic risk induced by ionizing radiation in the breasts of women undergoing mammography exams. MGD value is estimated from the incident air kerma (k i), associated with conversion factors which depend on the half-value layer (HVL), the breast composition and thickness compressed breast. This study aims to evaluate the influence of the parameters used to determine the MGD using different measurement detectors. Measurements were performed on a Siemens Mammomat Model 300 Nova mammography equipment; this has the combinations Anode/Filter of Mo/Mo, Mo/Rh and W/Rh. Detectors used were the ionization chamber Model 10X6-6M manufactured by Radcal Co., two solid-state detectors, one Model AGMS-M manufactured by Radcal Co. and other Model Xi Mammo manufactured by UNFORS. The detectors measures were compared and the MGD value was estimated; differences between measurements and the reference values were higher in HVL and k i parameters. The results are displayed according to other published works. (Author)

  19. Resistance evaluation expanded perlite the leaching acid: variation of parameters concentration, time and leaching agent; Avaliacao da resistencia da perlita expandida a lixiviacao acida: variacao dos parametros concentracao, tempo e agente lixiviante

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, J.M.F. de; Damasceno Junior, E.; Oliveira, E.S.; Fernandes, N.S., E-mail: janielequimicaufrn@gmail.com [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Instituto de Quimica. Laboratorio de Quimica Analitica e Meio Ambiente

    2016-07-01

    The expanded perlite is an amorphous aluminosilicate which presents in its composition about 75.0% silicon oxide (SiO2), also having other species in the composition as oxides of some metals. Silicas and silicates have been used in the environmental field, in relevant anti-corrosive activity. In this context, materials that exposes too many highly acidic media, require preservation against this type of wear, as this type of damage causes a great financial loss, thereby requiring low-cost, abundant materials, non-toxic and easy to purchase as some silica coating. The study evaluated the perlite expanded resistance against an acid leaching process. With undeniability the use of strong acids and different working conditions were not able to remove the oxides present on the expanded perlite sample, thus demonstrating the high strength of the expanded perlite against acid attacks. (author)

  20. Impact of electromechanical parameter variations in treatment volume doses and adjacent structures; Impacto da variacao dos parametros eletro-mecanicos nas doses do volume de tratamento e nas estruturas adjacentes

    Energy Technology Data Exchange (ETDEWEB)

    Morais, M.E.; Campos, A.M. [Instituto Nacional do Cancer (INCa), Rio de Janeiro, RJ (Brazil). Programa de Qualidade em Radioterapia]. E-mails: memorais@yahoo.com.br; amcampos@inca.gov.br; Goncalves, J. F. [Instituto de Oncologia e Radioterapia GV, Governador Valadares, MG (Brazil)]. E-mail: joelfgoncalves@yahoo.com.br; Ferreira, M.L. [Centro Radioterapico Gavea, Rio de Janeiro, RJ (Brazil)]. E-mail: mluciaf@yahoo.com

    2003-07-01

    ICRU Report 62 recommends that radiotherapy treatment dose should be prescribed in such a way that the dose to the target volume varies no more than 10%. In order to keep this goal, a very important role is played by the quality assurance (QA) of the treatment unit associated to the high level work of the personnel involved in planning and patient treatment. This paper shows the influence of the main electrical and mechanical linear accelerator parameters: field size, source-skin distance, gantry angle and light x radiation field coincidence in tumor volume and adjacent organ doses. We simulated a cubic tumor and a cubic adjacent critical organ in a cubic phantom and used a 3D Prowess system for planning. The treatment has been simulated for a 6 MV linear accelerator. We simulated two treatment planning: one using all the parameters inside their tolerance limits and another doubling these limits. The final results have show that, if the irradiation machine operates out of the tolerance limits, the dose variation in the planning target volume (PTV) can goes till {+-} 5,8% and in the critical adjacent organ till {+-} 7,7%. Therefore we concluded that, according to the complexity of the treatment, it can be necessary to reduce the tolerance levels advised by the IAEA/TECDOC - 1151. (author)

  1. Lab determination of soil thermal Conductivity. Fundamentals, geothermal applications and relationship with other soil parameters; Medida de la conductividad termica del suelo en laboratorio. Fundamentos fisicos, aplicaciones geotermicas y relaciones con otros parametros del suelo

    Energy Technology Data Exchange (ETDEWEB)

    Nope Gomez, F. I.; Santiago, C. de

    2014-07-01

    Shallow geothermal energy application in buildings and civil engineering works (tunnels, diaphragm walls, bridge decks, roads, and train/metro stations) are spreading rapidly all around the world. the dual role of these energy geostructures makes their design challenging and more complex with respect to conventional projects. Besides the geotechnical parameters, thermal behavior parameters are needed in the design and dimensioning to warrantee the thermo-mechanical stability of the geothermal structural element. As for obtaining any soil thermal parameter, both in situ and laboratory methods can be used. The present study focuses on a lab test known the need ke method to measure the thermal conductivity of soils (λ). Through this research work, different variables inherent to the test procedure, as well as external factors that may have an impact on thermal conductivity measurements were studied. Samples extracted from the cores obtained from a geothermal drilling conducted on the campus of the Polytechnic University of Valencia, showing different mineralogical and nature composition (granular and clayey) were studied different (moisture and density) compacting conditions. 550 thermal conductivity measurements were performed, from which the influence of factors such as the degree of saturation-moisture, dry density and type of material was verified. Finally, a stratigraphic profile with thermal conductivities ranges of each geologic level was drawn, considering the degree of saturation ranges evaluated in lab tests, in order to be compared and related to thermal response test, currently in progress. Finally, a test protocol is set and proposed, for both remolded and undisturbed samples, under different saturation conditions. Together with this test protocol, a set of recommendations regarding the configuration of the measuring equipment, treatment of samples and other variables, are posed in order to reduce errors in the final results. (Author)

  2. Evaluation of radiation protection parameters in dental radiography in the State of Rio de Janeiro, Brazil; Avaliacao de parametros de radioprotecao em radiologia odontologica no Estado do Rio de Janeiro

    Energy Technology Data Exchange (ETDEWEB)

    Dovales, Ana Cristina M; Oliveira, Sergio L. Girao de; Cucco, Antonio Carlos S; Bezerra, Marcos Antonio; Mota, Helvecio C [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil). Dept. de Fisica Medica

    2001-07-01

    This paper presents the results obtained in a program for the postal evaluation of radiation protection parameters in dental radiography in the state of Rio de Janeiro. The postal kit contains a radiographic film and two pairs of thermoluminescent dosimeters separated by a 3 mm aluminium filter and is accompanied by a questionnaire about equipment characteristics and exposition parameters. The analysis of 2596 equipment in the last three years showed that near half of the examinations produces doses higher than the diagnostic reference level established by the health authorities for this kind of examination. Field diameter is within the acceptable range in 73,5% of the tests and total filtration is higher than 1,5 mm Al equivalent in 86,64% of the cases. Comparing with earlier results this analysis suggests that radiation protection conditions in dental radiography are improving in the state of Rio de Janeiro. (author)

  3. Electrochemical noise of the erosion-corrosion of copper in relation with its hydrodynamic parameters; Ruido electroquimico de la erosion-corrosion en cobre: su relacion con los parametros hidrodinamicos

    Energy Technology Data Exchange (ETDEWEB)

    Castaneda, I.; Romero, M.; Malo, J.M.; Uruchurtu, J.

    2010-07-01

    This work presents the electrochemical noise results obtained of the surface degradation on copper, due to erosion corrosion phenomena, which were a function of the hydrodynamic parameters of the system (fluid movement). A modified rotating cylinder (RC) comprising three ring electrodes under two rotating speeds (880 and 1750 rpm with a Reynolds numbers 1486 Re and 2972 Re, respectively) were used. Characteristic electrochemical noise spectra as a function of the hydrodynamic parameters were found, as well as surface attack intensities the noise signal. An increase and a more uniform attack due to particle impact was related to larger particle size and lesser erosion corrosion intensity, in the form of more localized attack over the surface, was obtained for smaller ones. Erosion corrosion attack presents characteristic electrochemical current and potential noise signals, according to the laminar or transitional turbulent regime and particle size added. (Author).

  4. Radiation doses in mammography as planning parameters for premature breast cancer tracking programs; Doses de radiacao em mamografias como parametros de planejamento para programas de rastreamento do cancer precoce da mama

    Energy Technology Data Exchange (ETDEWEB)

    Souza Ferreira, Rubemar de

    1994-12-31

    Radiation doses are the main parameters applied to the evaluation of mammographic radiological impact. This study, for a sample of 407 women, were analyzed, through the thermoluminescent dosimetry, radiation doses in the surface of skin and glandular absorbed doses for cranio-caudal view. The results show the presence of a large dose range to the same mammographic procedure, which, analyzed enclosed with 585 facilities, suggest be necessary the standardization of the mammographic technique. From that results, with the additive model, the excess of breast cancer (radioinduced) and lifetime loss risk, for age groups between 30 and 70 years were estimated. Is demonstrated that the benefits from dedicated mammography, overcome the relationship among the epidemiological aspects of breast cancer and ionizing radiation as an harmful agent, which may show an important correlation for large exposed populations, point out the importance of the continuous risk and benefit evaluation to the new technologies introduced. (author). 86 refs., 40 figs., 14 tabs.

  5. Determination of the cell parameters of {beta}-quartz at 1003 K by neutron multiple diffraction; Parametros de rede do quartzo-{beta} a 1003 K determinados por difracao multipla de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Luiz Carlos de

    2002-07-01

    In this work, neutron multiple diffraction (NMD) data was employed for the determination of the parameters a and c of the {beta}-quartz hexagonal cell at 1003 K. An experimental 00.1 {beta}-quartz NMD 'Umweg' pattern has been used for the determinations. During the indexing of the {beta}-quartz pattern it was verified that most of the peaks could be classified as either 'good for the determination of the parameter a' or 'good for the determination of the parameter c'. With such a classification, it became possible to employ an iterative process for the determination of both parameters. To attain this purpose, two methods were developed. The first one, named 'absolute method', used angular azimuthal positions of the peaks, related to the origin of the experimental diagram. The second method, named 'relative method', used azimuthal angular differences between two selected peaks. The values obtained for both parameters, in the two methods employed, were found by applying the angular azimuthal positions, for the first method, and the azimuthal angular differences, for the second method, upon appropriate theoretical indexing diagrams. An iterative process was applied in order to obtain the values of the parameters. In this process, the value obtained for one of the parameters was used in the determination of the other parameter. The process continues until both parameters converge. The iterative process was used in both methods. The relative method proved to be better than the absolute method. The best values of the parameters obtained by the relative method were: a 4.99638 {+-} 0.00057 angstrom and c = 5.46119 {+-} 0.00044 angstrom. (author)

  6. The marginal cost of operation: a parameter for evaluating and regulating of the generation work program; O custo marginal de operacao: um parametro para a avaliacao e ajuste do programa de obras de geracao

    Energy Technology Data Exchange (ETDEWEB)

    Lima, W M; Mendes, L N.F.; Almeida Gattass, E de [FURNAS, Rio de Janeiro, RJ (Brazil)

    1990-12-31

    The Brazilian Generator System is predominantly hydroelectric, with some reservoirs having a pluri annual regularization, providing a large storage capacity of potential power for the system. This water storage allows the reduction of the alertly effect from the natural flow over the hydraulic resources for electric power production. Due to this structural characteristic, the main operation problem of the system refers to a strategical determination of storage energy utilization and, consequently, the thermal generation level. This paper examines the theoretical concepts referring to the survey of this operation strategies and analyses the factors for improving. These concepts are also extended for the interconnected electric subsystems case, mainly the interchange effect over the operation strategies of each subsystem. Finally, the natural flow sample influence over the marginal cost is analysed, comparing the obtained values with the historical sample and synthetical series of affluence. (C.G.C.). 7 refs, 2 figs, 5 tabs.

  7. Parâmetros de produtividade de um centro de material e esterilização Los parametros de productividad del centro de material y esterilización Productivity indicators in a sterilization central supply

    Directory of Open Access Journals (Sweden)

    Tânia Regina Sancinetti

    2007-06-01

    Full Text Available O estudo identifica parâmetros de produtividade no Centro de Material e Esterilização, com base em documentos, observação e cronometragem do processamento de duas amostras: caixa de herniorrafia e pacote de curativo. A produção média mensal foi de 30.466,42 artigos, a capacidade de produção, por hora, foi de 10,3 artigos por funcionário. O tempo de processamento do curativo do expurgo ao armazenamento foi, em média, de 295 minutos; o processo manual utilizou 46 minutos e o automatizado, 88 minutos. O tempo da caixa de herniorrafia foi de 329 minutos; o processo manual utilizou 60 minutos e o automatizado, 98 minutos. O processamento manual do curativo utilizou 59,23% horas produtivas no expurgo; 26,31% guarda e distribuição; 10,94% esterilização e 3,28% preparo. Quanto à caixa de herniorrafia: no preparo 16,20%; no expurgo 11,84%; na guarda e distribuição 7,47% e na esterilização 1,89%. Este estudo possibilitou aferir resultados e analisar o processo de trabalho no CME.El estudio identifica parámetros de productividad del Centro de Material y Esterilización, basados en documentos, observación y cronometraje procesadas en dos muestras: caja de herniorafia y fardo de curativo. El promedio de producción mensual fue de 30.466,42 artículos y el promedio de la capacidad de producción por hora fue 10,3 artículos por empleado. El tiempo de procesamiento del curativo del expurgo al almacenamiento fue en un promedio de 295 minutos; su proceso manual utilizó 46 minutos y lo automatizó en 88 minutos. El tiempo de la caja de herniorafia fue 329 minutos; su proceso manual utilizó 60 minutos y lo automatizó en 98 minutos. El procesamiento manual del curativo fue: 59,23% horas productivas encima del expurgo; 26,31% guarda y distribución; 10,94% esterilización y 3,28% preparo. Cuanto a la caja de herniorafia: en su preparo 16,20%; en el expurgo 11,84%; en la custodia y asignación 7,47% y en la esterilización 1,89%. El estudio posibilitó contrastar resultados y analizar el proceso de trabajo del CME.This study identifies productivity indicators at a Sterilization Central Supply (CME through documents, observation and time counting of the process for two items selected from the sample: a bandage pack and a herniorrhaphy box. The monthly average production was 30,466.42 items, and the production capacity per hour was 10.3 items per employee. The bandage pack averaged 295 minutes from the expurgation area to storage; the manual process lasted 46 minutes and the automated 88 minutes. For the herniorrhaphy box the average was 329 minutes; the manual process lasted 60 minutes and automated 98 minutes. In the bandage kit, the manual process used up 59.23% of the productivity hours in the expurgation area, 3.28% in the preparation, 10.94% in the sterilization process, and 26.31% in storage and distribution. Figures for the manual process of herniorrhaphy box were: expurgation, 11.84%; preparation, 16.20%; storage and distribution, 7.47%; and sterilization, 1.89%. The study made possible to assess the results and to analyze the working process at the CME.

  8. Experimental Research on The Deformability of a Geological Material: Initial Characterisation and Identification of Parameters; Estudio Experimental de la Deformabilidad de un Material Geologico: Caracterizacion Inicial e Identificacion de Parametros

    Energy Technology Data Exchange (ETDEWEB)

    Villar, M.V.; Udias, A.; Canamon, I.; Robles, J.

    2006-07-01

    This document reflects the work performed at CIEMAT (Engineered and Geological Barriers Group) in the framework of the RTD Project BTE2002-04244-C02-02 (DEF-NOSAT). The first phase of the project consisted on the selection and characterisation of a geological material fitted for unsaturated triaxial testing. The result obtained during this phase gave place to the selection of a silty clay from Alcala de Henares (Madrid, Spain). Compaction and permeability tests were performed as well as studies on mixtures of this soil with sand. With the selected mixtures (70/30 and 50/50 percent sand/soil) isotropic compression tests were carried out in the saturated sample. The results of these tests have allowed the determination of some of the parameters needed to model the mechanical behaviour of the soil. The report includes also a brief description of a methodology developed in the Department of Applied Mathematics and Computer Methods of the Universidad Politecnica de Madrid for getting these parameters by optimisation of the experimental results, as well as the results obtained. (Author) 25 refs.

  9. Nuclear parameters determination of the {sup 127}Te {beta} {sup -} decay: a proposal for teaching nuclear physics; Determinacao de parametros nucleares do nucleo de {sup 127}Te: uma proposta para o ensino de fisica nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Batista, Wagner Fonseca

    2011-07-01

    A study of the {sup 127}Te {beta}{sup -} decay was carried out by means of gamma spectroscopy measurements using high resolution HPGe detector, in the region from 30 keV to 1.0 MeV, aiming to get a better understanding of the {sup 127}Te nuclear structure. The radioactive sources of {sup 12}7Te were obtained from the {sup 126}Te(n,{gamma}){sup 1}'2{sup 7}Te nuclear reaction produced in the IEA- R1 nuclear reactor at IPEN/CNEN-SP. Five gamma {sup t}ransitions previously attributed to this decay were confirmed with a better precision than previously. The half-life of {sup 127}Te was also studied resulting in data with lower uncertainty. Using a set of data selected from gamma spectroscopy measurements was developed and applied a didactic proposal for high school students using the Excel software. (author)

  10. Determination of patterns of interplanar distances starting from crystalline parameters for the Cyber computer of the ININ; Determinacion de patrones de distancias interplanares a partir de parametros cristalinos para la computadora Cyber del ININ

    Energy Technology Data Exchange (ETDEWEB)

    Macias B, L.R

    1991-03-15

    In this report a program in Fortran language that reproduces the pattern of the Joint Committee on Powder Diffraction Standards is presented and that it can be applied to identify non well-known samples such as in those that only by means of articles or other sources the values of the parameters of the elementary cell are lightly known and by this way the correspondent diffraction pattern can be accurately generated. (Author)

  11. Optimization of the parameter calculation the process of production historic by using Parallel Virtual Machine-PVM; Otimizacao do calculo de parametros no processo de ajuste de historicos de producao usando PVM

    Energy Technology Data Exchange (ETDEWEB)

    Vargas Cuervo, Carlos Hernan

    1997-03-01

    The main objective of this work is to develop a methodology to optimize the simultaneous computation of two parameters in the process of production history matching. This work describes a procedure to minimize an objective function established to find the values of the parameters which are modified in the process. The parameters are chosen after a sensibility analysis. Two optimization methods are tested: a Region Search Method (MBR) and Polytope Method. Both are based in direct search methods which do not require the function derivative. The software PVM (Parallel Virtual Machine) is used to parallelize the simulation runs, allowing the acceleration of the process and the search of multiple solutions. The validation of the methodology is applied to two reservoir models: one homogeneous and other heterogeneous. The advantages of each method and of the parallelization are also present. (author)

  12. The influence of engine operating parameters on aldehyde emissions from an ethanol-fuelled vehicle; Influencia de parametros de operacao do motor nas emissoes de aldeidos por um veiculo a etanol

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Rinaldo Antunes [FIAT Automoveis S.A., Betim, MG (Brazil). Engenharia de Motores]. E-mail: expmotor@fiat.com.br; Sodre, Jose Ricardo [Pontificia Univ. Catolica de Minas Gerais, Belo Horizonte, MG (Brazil). Dept. de Engenharia Mecanica]. E-mail: ricardo@pucminas.br

    2000-07-01

    This work presents results and analysis of experiments on aldehyde emissions and on the regulated pollutants (CO, HC and NO{sub X}) emissions, with varying engine operational parameters in an ethanol-fuelled vehicle during a standard urban test cycle. The test cycle was carried out with the vehicle in a chassis dynamometer, and simulates an average urban trip of approximately 5,8 km, under steady state conditions. The varied parameters were fuel/air equivalence ratio, dash pot function, cut off function and gear change speed. The results found showed lower aldehyde emissions for gear change at lower speeds and for richer mixtures. (author)

  13. Influence of process parameters on the cavitation resistance of arc thermally sprayed cobalt stainless steel; Influencia dos parametros de processo na resistencia a cavitacao de uma liga inoxidavel com cobalto aspergido a arco

    Energy Technology Data Exchange (ETDEWEB)

    Pukasiewicz, A. [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Capra, A.R.; Chandelier, J. da L. [Instituto de Tecnologia para o Desenvolvimento (LACTEC), Curitiba, PR (Brazil)], e-mail: anderson.geraldo@lactec.org.br; Paredes, R.S.C. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Engenharia Mecanica

    2006-07-01

    In this work the influence of the arc thermal spraying process on the microstructure, oxide volumetric fraction, porosity and cavitation resistance was studied. The characterization was performed by optical and electrical microscopy, microhardness and ultrasonic cavitation test, ASTM G32-96 in AS895HY cobalt stainless steel. The increase in air pressure, 280 to 410 kPa, modified the oxide fraction from 17,2 +- 3,6% to 10,9 +-1,8%, in the samples without pre-heating treatment. With 120 deg C pre-heating treatment the oxide fraction increase from 24,1 +- 2,8% to 12,8 +- 1,9% when the air pressure was modified from 280 to 550 kPa. The mass loss in vibration-induced cavitation were 1,55 and 1,42 mg/h for 410 kPa AS895HY samples, with and without pre heating treatment, and 2,12 mg/h for 280 kPa samples without pre heating treatment. The results showed that the process parameters modified the microstructure and the cavitation resistance of the arc thermal spraying coatings. (author)

  14. Pharmacokinetic parameters of ethylnitrosourea, methylnitrosourea and dimethylnitrosamine determined since their clastogenic activity in mice; Parametros farmacocineticos de la etilnitrosourea, la metilnitrosourea y la dimetilnitrosamina determinados a partir de su actividad clastogenica en ratones

    Energy Technology Data Exchange (ETDEWEB)

    Morales R, P.; Vallarino K, T. [Instituto Nacional de Investigaciones Nucleares, Departamento de Biologia, A.P. 18-1027, goscinski11801 Mexico D.F. (Mexico)

    1997-07-01

    The latent period (PL) and the effective activity time (TAE) of ethylnitrosourea (ENU), dimethylnitrosamine (DMN) and methylnitrosourea (MNU) were determined through comparison of production kinetics at micronucleus polychromatic erythrocytes in peripheric blood of mice caused by these agents, with that one produced by gamma radiation. Starting from the fact that acute exposure to ionizing radiation causes damage in the genetic material immediately, therefore PL and TAE in this case are practically zero. The obtained results show that PL for 25 or 50 mg ENU/kg is 3.6 and 1.6 h respectively, although the differences among them were not significant. These data show that ENU reaches marrow relatively fast. TAE for the same doses was 5.3 h and 17 h. This shows that mutagen is not depurated very quickly and while doses is greater time is longer in that mutagen can performs. The induction curve of EPC-MN by DMN (8 mg/kg) showed two peaks, what suggests that can be involucred two metabolites, two MN induction mechanisms or two leisure types. The fact that the second peak were not presented in all the animals and that the time of appearance were not regular, it suggests an effect maybe metabolic that is associated to the high toxicity of DMN. PL and TAE calculated in the first peak were of 9.7 h and - 2.2 h being statistically significant only PL. The fact that its PL was too greater it is in according with its requirement of bioactivation in the liver. On the other hand what TAE were too low its shows that DMN is eliminated fastly by the organism. The MNU at 4 and 8 mg/kg doses has a PL over 15 h, which is very large for a direct mutagen and a TAE very short since even its duration is lesser than in the radiation case, this shows that MNU reacts quickly, or what its metabolic degradation velocity and/or excretion are very fast. (Author)

  15. Effects of chemical composition and test parameters on the hot ductility of C-Mn-Al steels; Efeito da composicao quimica e parametros de ensaios sobre a ductilidade a quente de acos C-Mn-Al

    Energy Technology Data Exchange (ETDEWEB)

    Macedo, Marcelo C.S. de; Comineli, Osvaldo G; Pancieri, Jose G.P.; Oliveira, Maria A.L. de [Espirito Santo Univ., Vitoria, ES (Brazil). Dept. de Engenharia Mecanica; Souza Lima Cardoso, Geraldo I. de [Companhia Siderurgica de Tubarao (CST), Serra, ES (Brazil); Mintz, Barry [The City Univ., London (United Kingdom)

    1987-12-31

    The effects of Al content, as well as hot tensile test parameters on hot ductility of two C-Mn-Al steels are presented. Thermal cycle were carried out to study the influence of thermal oscillations during those compositions cooling, consisting of heating the samples up to a solubilization temperature, high enough to dissolve any phase which could possibly be present in the original ingot, and also to produce a coarser grain size. After 5 minutes at 1330 deg C, the steels were cooled in three different ways to reach test temperature and samples remain at this temperature for 5 minutes for stabilization before testing. Further, a preliminary comparison between hot ductility results, obtained when samples are molten and continuously cooled at two different rates, and those obtained for solution treated samples which are cooled at an intermediate cooling rate. For the two composition solution treated, a ductility was observed trough displaced from each other about 50 deg C, being the Al content the responsible for this difference. (author) 14 refs., 11 figs., 1 tab.

  16. Study and parameters survey for iodine-125 source dosimetry to be applied in brachytherapy; Estudo e levantamentos de parametros para dosimetria de fontes de iodo-125 aplicadas em braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Eduardo Santana de

    2011-07-01

    The use of brachytherapy technique with iodine-125 seeds to prostate cancer treatment has been used for decades with good clinical outcomes. To aim the Brazilian population necessities, IPEN-CNEN/SP developed the iodine-125 seed prototype with national technology. The objectives of this work are the development and the study of dosimetric procedures associates with the experimental acquisition of the useful parameters for the iodine-125 dosimetric characterization and to evaluate if the developed procedures, in this work, have the basic conditions to determinate the dosimetric analysis, that are fundamental for clinical procedures. The dosimeters selected for the analysis are the TLD-100 (LiF:Mg,Ti), initially these dosimeters were submitted for two selection steps to choose the dosimeters more reproducible for the dosimetric analysis. The two steps were the selection by the mass of the dosimeters and the reproducibility after four irradiation series in a Cobalt-60 irradiator (CTR-IPEN). Afterwards these steps, the dosimeters were irradiated in linear accelerator with 6 MV energy (Service of Radiotherapy - Hospital Israelita Albert Einstein) to yield the individual calibration factors to each dosimeter. After, the dosimeters were used to the irradiations with iodine-125 seed, 6711 model, (GE-Healthcare). The irradiations and others analysis with iodine-125 seeds yield the useful values for the determination of the parameters suggested by the AAPM (American Association of Physicists in Medicine): constant of dose rate, geometry function, dose radial function and anisotropy function. The results showed good agreement with the values published by the literature, for the same iodine- 125 model, this fact confirms that the realized parameters will be able to be used for the IPEN-CNEN iodine-125 seeds dosimetry and quality control. (author)

  17. A two-parameter approach for the analysis of the effect of the weld metal on the constraint; Una enfoque de dos parametros para el analisis del efecto del cordon de soldadura sobre el constrenimiento

    Energy Technology Data Exchange (ETDEWEB)

    Leiva, R.; Donoso, J. R.; Muehlich, U.; Labbe, F.

    2004-07-01

    The effect of the mismatched weld metal on the stress field close to the crack tip in an idealized weld joint made up of base metal (BM) and weld metal (WM), with the crack located in WM, parallel to the BM/WM interface, was numerically analyzed. The analysis was performed with a J-Q type two-parameter approach with a Modified Boundary Layer, MBL, model subject to a remote displacement field solely controlled by K{sub 1} in order to eliminate the effect of the geometry constraint. The numerical results show that the constraint level decreases for overmatched welds (yield stress of WM higher than that of BM), and increases for under matched welds (yield stress of WM lower than that BM). The constraint level depends on the degree of the mismatch, on the width of the weld, and on the applied load level. (Author) 21 refs.

  18. Determination of structural geometric parameters of industrial ceramic foams by gamma rays transmission and X-rays microtomography; Determinacao de parametros geometricos estruturais de espumas ceramicas industriais por transmissao de raios gama e microtomografia de raios X

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Wilson Roberto Dejato da

    2005-07-01

    In this work, the gamma rays transmission and X-rays microtomography techniques are used for the evaluation of the porosity and the pore size distribution of SiC ceramic foams. It was also accomplished the three-dimensional images after the determination of samples geometric parameters. The geometric parameters were obtained by two-dimensional images analyses, generated by a Microfocus system, with a CCD camera, an images intensifier, a X-rays tube and an automatic system for rotation of the sample. The spatial resolution of the images was about 32 {mu}m. In the gamma rays transmission methodology, a Nal(Tl) scintillation detector, an {sup 241}Am (59.53 keV, 100 mCi) radioactive source and an automatic X-Z micrometric table was used. The analyzed samples had pores density of 30, 45, 60, 80 and 100 ppi (pores per inch). The gamma rays transmission technique was accurate to supply the porosity of the samples, which ranged about 90% and was in agreement with the values supplied by manufacturer of the foams. The 30 and 45 ppi samples analyzed by X-rays microtomography showed porosity results that agree with the average porosity supplied by the manufacturer. In other hand, the 60, 80 and 100 ppi samples systematically showed average porosity about 4%, lower than the average of the manufacturer. The pore size distributions found through the software IMAGO show the presence of smaller pores than those nominated by the manufacturer. The 30 ppi samples had voids inside the solid material of the ceramic foams structure. Gaussian truncated method, used in the three-dimensional reconstruction, was not able to take into the account the voids inside the solid matrix. (author)

  19. Study of parameters that influence the process of biosorption in the removal of heavy metals; Estudo de parametros que influenciam o processo de biossorcao na remocao de metais pesados

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Albina S.; Duarte, Marcia M.L.; Nandenha, Julio; Macedo, Gorete R. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2004-07-01

    The removal of heavy metal by microbial biomass have been investigated as an alternative to the traditional methods. The removal of the heavy metals copper and iron from discarded lubricating-oil was studied using the biosorbent Sargassum sp. It was chosen a discarded lubricating-oil of a bus fleet from the city of Natal-RN-Brazil. The oil was characterized to determine and quantify the heavy metals present. The effect of biomass protonation was performed in order to increase the removal efficiency of the metals. The equilibrium time between the oil and the biomass was determined. It was found that after 10 hours the equilibrium was reached. It was also studied the influence of biomass quantity. The results showed that the biomass quantity is an important parameter to the efficiency and biosorption capacity. The protonated biomass was shown more efficient to removal of Fe and Cu, removing 37,53% and 31,63% respectively. (author)

  20. Study of the parameters solution blow spinning technique in the obtaining of mullite nanofibers; Estudo de parametros da tecnica de fiacao por sopro em solucao na obtencao de nanofibras de mulita

    Energy Technology Data Exchange (ETDEWEB)

    Severo, L.L.; Farias, R.M.C.; Menezes, R.R.; Santos, M.A., E-mail: lucasleite_14.1@hotmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil)

    2016-07-01

    The Solution Blow Spinning (SBS) technique which use aerodynamic forces and has a high production rate, was created for production of nanofiber with versatile way, such as electrospinning. Therefore, the objective is to analyze the process parameters in order to optimize the production of mullite nanofiber using the SBS technique to determine the influence of air pressure, the concentration of the polymer and ejection rate in the diameter of the fibers. For this, it was used PVC as polymer in spinning, tetrahydrofuran as the solvent, HCl as acidifying, aluminum nitrate nonahydrate and tetraethylorthosilicate as precursors of mullite. The nanofibers obtained were heat treated at 1100°C. From of XRD and SEM results, it was proved the achievement of mullite nanofiber, and STATISTICA 7 software revealed that only ejection rate and the concentration influence in the average diameters of the fibers. (author)

  1. The use of edaphic parameters as indicators of soil erosion risk, Rambla of Las Moreras (SE Spain); El uso de parametros edaficos como indicadores de riesgo de erosion. Rambla de Las Moreras, Murcia, Se de Espana

    Energy Technology Data Exchange (ETDEWEB)

    Romero Diaz, A.; Quinonero Rubio, J. M.; Ortiz Silla, R.; Sanchez Navarro, A.; Fernandez-Delgado Juarez, M.; Gil Vazquez, J. M.

    2009-07-01

    One factor that more involved in the soil erosion soil is erodibility. In this paper we study some parameters (texture, structure, organic material, profundity and vegetal cover in the basin of Rambla de las Moreras (Murcia) with the objective of determining whether any of them can server of erosion risk indicators. the results sampling as the organic matter and the stability of aggregates can be good indicators of this. (Author) 6 refs.

  2. Analysis of the value recommended by the NCRP 151 and its relationship with Brazilian parameters;Analise dos valores recomendados pelo NCRP 151 e sua relacao com parametros brasileiros

    Energy Technology Data Exchange (ETDEWEB)

    Groppo, Daniela P. [UNESP, Botucatu, SP (Brazil). Inst. de Biociencias; Martins, Homero L. [Hospital A.C. Camargo, Sao Paulo, SP (Brazil). Servico de Fisica Medica

    2009-07-01

    The methodology proposed by the National Council on Radiation Protection 151 (NCRP 151), relates technical information necessary to structural shielding design and evaluation for megavoltage X- and gamma- ray radiotherapy facilities. However, many parameters used to calculate the shield are based on estimates, and may not be adequate to the Brazilian reality. Thus, the central idea of this study is to obtain parameters and is to outline a profile closer to the treatments carried out in facilities in Brazil, through a data collection routine of the Department of Radiotherapy Service of the Real e Benemerita Associacao Portuguesa de Beneficencia, in particular the cobalt therapy Theratron 780 (Atomic Energy of Canada Ltd.) and the linear accelerator Varian Clinac 2100C for measurement of workload, use factor, number of patients, fields, dose and anatomic region treated. So, the work did not draw definite values of the parameters, but indicative values were obtained which showed the importance to carry out more detailed studies of the recommended values. (author)

  3. Parameters of calibration of the measurement system of {sup 222} Rn based in LR-115; Parametros de calibracion del sistema de medicion de {sup 222} Rn basado en LR-115

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, M.L.; Mireles, F.; Quirino, L.; Davila, I.; Lugo, F.; Pinedo, J.L. [CREN-UAZ, 98068 Zacatecas (Mexico); Chavez, A. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: mluisagb@hotmail.com

    2003-07-01

    Since the SSNTD technique (Solid State Nuclear Track Detection) it was discovered it has been used as passive method for the detection of subnuclear particles in great variety of fields of the science. The use of the technique in measurements of {sup 222} Rn in air have already been established implying better methodologies in the exhibition to the environment until their engraving and reading processes. The SSNTD technique is since a method by comparison since the material it can be used a single time, therefore it requires of calibration in one controlled radon atmosphere, using gauged standards. The objective of this work is to show the calibration of the devices used as radon monitors based on SSNTD. The material used as SSNTD is LR-115 Il. The standardization of the parameters used in the exhibition to radon in air, engraving and reading process, its are based on the response of the LR-115 Il, the one arrangement of the device, engraving speed and mainly the calibration factor. They are considered two types of monitors: Open camera and Closed camera, the difference among the calibration factors of both cameras is the percentage of the descendants of radon in the open camera. The standardized parameters are operation voltage of the counting system; temperature, time and concentration of the engraving solution; and thickness. (Author)

  4. Study of the acquisition and reconstruction parameters of myocardial perfusion images in the detection of lesions; Estudo dos parametros de aquisicao e reconstrucao em imagens de perfusao de miocardio na deteccao de lesoes

    Energy Technology Data Exchange (ETDEWEB)

    Favero, Mariana S.; Finatto, Jerusa D.; Friedrich, Barbara Q.; Silva, Ana Maria M., E-mail: mariana.saibt@acad.pucrs.br [Pontificia Universidade Catolica do Rio Grande do Sul (NIMed/PUCRS), Porto Alegre, RS (Brazil). Nucleo de Pesquisas em Imagens Medicas; Mazzola, Carolina F.S. [Hospital Sao Lucas (HSL/PUCRS), Porto Alegre, RS (Brazil). Servico de Medicina Nuclear

    2012-12-15

    The aim of this paper was to analyze the influence of different acquisition parameters and reconstruction methods used in myocardial SPECT examinations in order to optimize the image of the left ventricle, allowing better visualization of lesions. For this purpose, a study was performed with images acquired on a Philips Forte SPECT equipment with an anthropomorphic phantom with cardiac insert filled with Tc-99m. Acrylic regions, representing cold lesions, were inserted into the lateral septum. The image was evaluated by profile counting, relative contrast and polar map. It was observed that the different parameters and acquisition reconstruction methods do not produce significant visual differences in the resulting images. Quantitatively, the acquisition with 64 projections reconstructed with the iterative method has a higher contrast. (author)

  5. Levels of dose in head exams by TAC in Cuba. Interrelation with parameters of image quality; Niveles de dosis en examenes de craneo por TAC en Cuba. Interrelacion con parametros de calidad de imagen

    Energy Technology Data Exchange (ETDEWEB)

    Fleitas Estevez, Ileana; Mora Machado, Roxana de la; Guevara Ferrer, Carmen R. [Centro de Control Estatal de Equipos Medicos (CCEEM), La Habana (Cuba)

    2001-07-01

    In the last years an increment in the use of Computer Tomography (CT) has been observed as an efficient diagnostic method. On the other hand, this type of study involves high doses levels which are imparted to the patient. In Cuba, there are not reported values of that doses levels for typical CT studies. The National Control Center for Medical Devices has been developing for several years investigations for knowing the guidance doses levels for different examinations in radiodiagnosis, taking into account the recommendations made for The International Basic Safety Standards, which have been adopted in Cuba. This paper presents an study of imparted doses for typical head examinations in 10 CT scanners (6 are helical and 3 axial technology). Values of CTDI, CTDIw (weighed) and nCTDIw (weighted and normalized) were calculated. The relation between CTDI at surface and CTDI in the center of the phantom for the highest slice width was calculated for each CT scanner. Others parameters, such as CT number and its special uniformity, noise, contrast scale, sensibility profiles, MTF evaluation, table movement and alignment between lasers and radiation field, have also obtained. These parameters were evaluated by means of the manufacturer's phantom (Siemens). (author)

  6. Physicochemical study of parameters for the production of mortar using industrial waste and construction; Estudo de parametros fisicoquimicos para a producao de argamassas utilizando residuos industriais e da construcao civil

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, K.C.; Goncalves, S.G. e; Souza, J. A. da S.; Felipe, A.M.P.F., E-mail: keyllafcastro@yahoo.com.br [Universidade Federal do Para (UFPA), PA (Brazil)

    2014-07-01

    The mortars can be considered as a mixture of the binders and aggregates with water, having capacity of the induration and adherence. Instead, it is suggested the production of mortars using civil construction waste, with plenty silicoaluminate, obtained in demolitions and reforms of build, and fly ash as material pozzolana, obtained of the combustion of mineral coal in fluidized bed boilers, in partial replacement of Portland cement. The civil construction wastes were benefited and characterized by X-ray spectrometry and X-ray diffraction. The fly ash was characterized by granulometric analyze and X-ray spectrometry. The mortars of the were prepared using the following compositions of RCC, 95, 90, 85, 80, 75 and 70%; CV of 0, 5, 10, 15, 20 and 25% e 5% of Portland CP II Z 32 cement. In all the compositions were put 0,8% of water and the rheological testing was used the same proportions residue (RCC e CV) with 35% water. The specimens were cured for 28 days and after were submitted physical trials of absorption, porosity and bulk density; mechanical trials of resistance to compression and analysis of X-ray diffraction and scanning electron microscopy. The results obtained show that the recycling of civil construction waste and the use of fly ash and RCC is a promising technique in production of mortars. (author)

  7. Development of an Android application to estimate the parameters of DEP from the radiographic exam; Desenvolvimento de um aplicativo Android para estimativa da DEP a partir de parametros do exame radiografico

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Flavio Augusto P.; Soares, Carina Klein, E-mail: prof.flavio@gmail.com, E-mail: ninacks@terra.com.br [Instituto Federal de Educacao, Ciencia e Tecnologia de Santa Catarina (IFSC), Florianopolis (Brazil). Curso Superior de Tecnologia em Radiologia; Martins, Alex Sander C.; Filgueiras, Tatiana Pereira, E-mail: alexscm1@gmail.com, E-mail: tatiana.filgueiras@ifsc.edu.br [Instituto Federal de Educacao, Ciencia e Tecnologia de Santa Catarina (IFSC), Florianopolis (Brazil). Curso Tecnico de Informatica; Recalcatti, Victor; Heis, Adriano, E-mail: victor_nba@hotmail.com, E-mail: adriano.heis@ifsc.edu.br [Instituto Federal de Educacao, Ciencia e Tecnologia de Santa Catarina (IFSC), Florianopolis (Brazil). Curso Superior de Tecnologia Gestao da Tecnologia da Informacao

    2013-10-01

    The objective of this research was to develop an application for the Android operating system to calculate the entrance dose in the skin - DEP for the professional radiological techniques can estimate the dose absorbed by the patient. The application was written with the help of the ECLIPSE development suite together with the Google SDK. The DEP-Calc was designed to be used in a mobile device, so the program consists of simple and self-explanatory screens, occupies a small space in the internal memory of the device and is easy to use.To obtain the value of the DEP of a radiographic examination, the practitioner provides the variables used in the examination as well as the device, and from this information, the program calculates the value of the DEP. With its use, as well as meet a legal requirement, allows an improvement in image quality and dose optimization, since the professional has knowledge of the radiation produced. (author)

  8. Theoretical and experimental studies of reverse osmosis separation of inorganic salts in aqueous solutions; Estudio teorico y experimental de parametros de transporte a traves de membranas de osmosis inversa : Efecto de varios tipos de sales

    Energy Technology Data Exchange (ETDEWEB)

    Khavet, M.; Mengual, J. I.

    2004-07-01

    Theoretical and experimental studies of reverse osmosis separation of inorganic salts in aqueous solutions have been carried out. In this study, a polyamide thin film composite membrane in spiral wound configuration was used. The free energy of different inorganic monovalent (LiCl, NaCl, KCl, NaBr, NaI, LiBr, KBr) and divalent (MgCl2, MnCl2, CaCl2, MgBr2) salts has been calculated. The solute transport parameters were related to the free energy of the corresponding cations and anions. The mass transfer coefficient at the high pressure feed side of the spiral wound module was determined for each type of salt. The obtained theoretical values were compared to the experimental ones. The good agreements observed between the experimental and theoretical results confirm the validity of the theoretical procedure, which may be applied in modelling solar reverse osmosis plants for the prediction of the separation factor of various types of inorganic salts. (Author)

  9. Influence of atomic and nuclear constants on the counting efficiency for 55{sup F}e in liquid scintillators; Influencia de los parametros atomicos y nucleares en la calibracion de 55{sup F}e mediante centelleo liquido

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, A.; Grau, A.; Arcos, J. M. los

    1985-07-01

    In this paper one considers the influence of the different parameters on the determination of the uncertainty of the detection efficiency for 55{sup F}e when the counting technique of liquid scintillation is applied. The following parameters are considered: the relative probabilities of X and Auger emission so as their corresponding energies, the fluorescence yields W{sup K} and W{sup L}, and the non-interaction probabilities of the emitted X photons. (Author) 11 refs.

  10. RELACION ENTRE LA ENTALPÍA DE INMERSIÓN DE UN CARBÓN ACTIVADO EN SOLUCIONES ACUOSAS DE Pb2+ Y LOS PARAMETROS DE ADSORCIÓN

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo

    2008-03-01

    Full Text Available Se prepara un carbón activado a partir de carbón mineral por impregnación con solución al 50% de ácido fosfórico, el cual presenta un área superficial de 586 m2.g-1 y un volumen total de poro de 0,37 cm3g-1; en lo que respecta a características químicas el carbón activado presenta un mayor contenido de sitios ácidos, 0,92 meq g-1, que de sitios básicos, 0,63 meq g-1 , que le proporcionan una característica aproximadamente neutra con un pHPZC de 7,4.La cantidad adsorbida de Pb2+ y la entalpía de inmersión en soluciones de a diferentes valores de pH,  muestran que estos valores son máximos para pH 4 con valores de 15,7 mgg-1 y 27,6 Jg-1 respectivamente. Se establecen comportamientos semejantes de la entalpía de inmersión y la cantidad adsorbida en función del pH; y se obtienen relaciones del tipo función de segundo grado entre la constante de adsorción y la entalpía de inmersión y entre dicha constante y el pH de la solución.

  11. Jet Grouting. Control of execution and result parameters. Test fields - Experience in Chile; Jet Grouting. Control de parametros de ejecucion y de resultados. Campos de prueba-Experiencia en Chile

    Energy Technology Data Exchange (ETDEWEB)

    Ayarza, P. M.; Vukotic, G.

    2014-07-01

    This article emphasizes the importance of Test Fields in project that includes the Jet Grouting technique. In particular, the Chilean experience is analyzed, where the Jet Grouting was first introduced by Pilots Terratest S. A. in the year 2010, only, only in 2011 the first project using jet columns was constructed. The versatilely of this technique allows its use in a wide variety of projects, for example, soil capacity improvement, settlement control, reduction of soil permeability and other environmental applications. Currently, the most common applications are underpinning existing foundations, ground improvement, lateral support of excavations, hydraulic barriers, slope stabilization, liquefaction control, among others. The Jet Grouting is one of the most demanding soil improvement technique and requires excellence in designing and execution engineers and other involved specialist. It is therefore essential to ensure exhaustive control to the execution and final parameters, in order to check that the product- Jet Grouting element-have the design properties, and implement modifications if necessary. Many authors strongly advises that if there is no comparable experience and even if there is, a Test Field of Jet Grouting elements has to be executed in site. This field consists in a nearby area with similar geotechnical conditions of the project, where Jet Grouting test columns will be constructed. This Test Field will allow selecting the most effective execution parameters and verifying that the final product has he correct design properties. (Author)

  12. State variables applied in the analysis of transmission lines considering the influence of frequency on the longitudinal parameters; Variaveis de estado aplicadas na analise de linhas de transmissao considerando a influencia da frequencia nos parametros longitudinais

    Energy Technology Data Exchange (ETDEWEB)

    Monzani, R.C. [Universidade Estadual de Londrina (UEL), PR (Brazil). Centro de Tecnologia e Urbanismo. Dept. de Engenharia Eletrica; Prado, A.J.; Kurokawa, S.; Bovolato, L.F. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Ilha Solteira, SP (Brazil). Fac. de Engenharia. Dept. de Engenharia Eletrica; Pissolato Filho, J. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Eletrica e Computacao. Dept. de Sistemas e Controle de Energia

    2009-07-01

    This paper presents a mathematical model to simulate and analyze time-domain electromagnetic transients in a transmission line using a single-phase representation of these lines with and without the influence of frequency on the longitudinal parameters. For this {pi} circuits and state variables are used to compose a linear system which is solved by a numerical routine. This routine is applied to the mathematical tool MatLab {sup TM} The aim of this paper is to demonstrate quickly and efficiently the study of electromagnetic waves to graduate students in Electrical Engineering, Computing and Mathematics courses, because EMTP (Electromagnetic Transient Program ) involve a greater complexity in handling which and can often lead disinterest in these individuals.

  13. Effect of some parameters in the response of the Perspex 3042, Lot L amber dosemeters; Efectos de algunos parametros en la respuesta de los dosimetros ambar Perspex 3042, Lote L

    Energy Technology Data Exchange (ETDEWEB)

    Prieto M, E.F.; Barrera G, G. [Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear (CEADEN). Calle 30, No. 502, esq. 5ta. Avenida, Playa, Ciudad de La Habana (Cuba)]. e-mail: efprieto@ceaden.edu.cu

    2004-07-01

    The answer of the dosimetric systems is affected by several factors, for what should know as these factors they influence in each one of the different dosimetric systems and by this way to minimize its effect in the value of the absorbed dose and to obtain exact dose values. One of the dosimetric systems more used in the high dose dosimetry like routine dosemeter for the control of the irradiation process are the Perspex dosemeters, for their speed in the obtaining the information, their easy manipulation and the precision that they present. To this dosemeters group they belong the same as the Red and Clear the Amber, which are adequate for the measurement of the radiation dose in the range of high doses. The objective of the present work is to obtain the calibration curves of the dosemeters Amber Perspex 3042, Lot L under our work conditions, like they are the irradiation temperatures and of storage and to know the influence of the rate dose in the value of the absorbed dose for different measurement wavelengths, as well as, the relationship among the one post-irradiation time and the specific absorbance value induced in function of the absorbed dose. (Author)

  14. Application of the physiological and morphological parameters of the brazilian population sample to the mathematical model of the human respiratory tract; Aplicacao dos parametros fisiologicos e morfologicos de uma amostra da populacao brasileira no modelo matematico do trato respiratorio humano

    Energy Technology Data Exchange (ETDEWEB)

    Reis, Arlene Alves dos

    2005-07-01

    The Human Respiratory Tract Model proposed by the ICRP Publication 66 accounts for the morphology and physiology of the respiratory tract. The characteristics of air drawn into the lungs and exhaled are greatly influenced by the morphology of the respiratory tract, which causes numerous changes in pressure, flow rate, direction and humidity as air moves into and out of the lungs. Concerning the respiratory physiological parameters the breathing characteristics influence the volume, the inhalation rate of air and the portion that enters through the nose and the mouth. These characteristics are important to determine the fractional deposition. The model uses morphological and physiological parameters from the Caucasian man to establish deposition fractions in the respiratory tract regions. It is known that the morphology and physiology are influenced by environmental, occupational and economic conditions. The ICRP recommends, for a reliable evaluation of the regional deposition, the use of parameters from a local population when information is available. The main purpose of this study is to verify the influence in using the morphology and physiology parameters representative of a sample of the Brazilian population on the deposition model of the ICRP Publication 66. The morphological and physiological data were obtained from the literature. The software EXCEL for Windows (version 2000) was used in order to implement the deposition model and also to allow the changes in parameters of interest. Initially, the implemented model was checked using the parameters defined by the ICRP and the results of the fraction deposition in the respiratory tract compartments were compared. Finally, morphological and physiological parameters from Brazilian adult male were applied and the fractional deposition calculated. The results suggest a significant variation in fractional deposition when Brazilian parameters are applied in the model. (author)

  15. Determination of the physical parameters of the nuclear subcritical assembly Chicago 9000 of the IPN using the Serpent code; Determinacion de los parametros fisicos del conjunto subcritico nuclear Chicago 9000 del IPN usando el codigo SERPENT

    Energy Technology Data Exchange (ETDEWEB)

    Arriaga R, L.; Del Valle G, E. [IPN, Escuela Superior de Fisica y Matematicas, Av. Instituto Politecnico Nacional s/n, U.P. Adolfo Lopez Mateos, Col. San Pedro Zacatenco, 07738 Mexico D. F. (Mexico); Gomez T, A. M., E-mail: guten_tag_04@hotmail.com [ININ, Departamento de Sistemas Nucleares, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2013-10-15

    For the Serpent code was developed the three-dimensional model corresponding to the nuclear subcritical assembly (S A) Chicago 9000 of the Escuela Superior de Fisica y Matematicas del Instituto Politecnico Nacional (ESFM-IPN). The model includes: a) the core, formed by 312 aluminum pipes that contain 5 nuclear fuel rods (natural uranium in metallic form), b) the multi-perforated plates where they penetrate the inferior part of each pipe to be able to remain in vertical form, c) water, acting as moderator and reflector, and d) the recipient lodging to the core. The pipes arrangement is hexagonal although the transversal section of the recipient that lodges to the core is circular. The entrance file for the Serpent code was generated with the data provided by the manual of the S A use about the composition and density of the fuel rods and others obtained in direct form of the rods, as the interior and external diameter, mass and height. Of the obtained physical parameters, those more approached to that reported in the manual of the subcritical assembly are the effective multiplication factor and the reproduction factor η. The differences can be because the description of the fuel rods provided by the manual of the S A use do not correspond those that are physically in the S A core. This difference consists on the presence of a circular central channel of 1.245 diameter centimeters in each fuel rod. The fuel rods reported in the mentioned manual do not have that channel. Although the obtained results are encouraging, we want to continue improving the model to incorporate in this the detectors, defined this way by the Serpent code, which could determine the existent neutrons flux in diverse points of interest like the axial or radial aligned points and to compare these with those that are obtained in an experimental way when a generating neutrons source (Pu-Be) is introduced. Added to this effort the cross sections for each unitary cell will be determined, so that these are used in a transport code developed in the ESFM-IPN. (Author)

  16. Systems for the calculation of electrical parameters and energy efficiency for high-capacity hydroelectric generators; Sistemas para el calculo de parametros electricos y eficiencia energetica para generadores hidroelectricos de gran capacidad

    Energy Technology Data Exchange (ETDEWEB)

    Reyes Martinez, Oscar Alfonso; Pascacio de los Santos, Alberth; Perez Abad, Carlos Alberto [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Leon Rivera, Nicolas [CFE-LAPEM, Irapuato, Guanajuato (Mexico)

    2012-07-01

    In recent years, the Comision Federal de Electricidad (CFE) has developed important hydroelectrical power projects in Mexico. Most of them are located in the Santiago River Hydrological System in Nayarit, Mexico. A total of 27 projects with a capacity of 4,300 MW are considered but only 32% of them have been carried out. One of the most ambitious projects that continue in process of construction is the Hydroelectrical Plant La Yesca. This project will conclude in late 2012 and consists of two electric generators of 375 MW, 17 kV. It will be second in power and the third in electrical generation at the system. According to national and international standards, a set of static and dynamic tests must be performed in these generators before commissioning, to ensure their proper operation. Winding stator high voltage endurance test, three phase sudden short circuit test and energy efficiency calculation are some of the most important tests to be performed in a new electrical generator. These tests are difficult to perform on-site due to the equipment capacity required, so very few companies in the world can conduct them. In Mexico no one has the necessary infrastructure for testing in high capacity hydroelectric generators such as those from La Yesca, so the Laboratorio de Pruebas a Equipos y Materiales (LAPEM) has invested in projects to improve this project in order to meet the needs of the Mexican electricity sector. This paper is a description of the systems developed for the calculation of electrical parameters and energy efficiency for this class of generators. [Spanish] En los ultimos anos, la Comision Federal de Electricidad (CFE) ha desarrollado importantes proyectos hidroelectricos en Mexico. La mayor parte se ubican en el Sistema Hidrologico del Rio Santiago en Nayarit, Mexico. Se consideran un total de 27 proyectos con capacidad de 4300 MW, pero solo 32 % de ellos se han llevado a cabo. Uno de los proyectos mas ambiciosos que continua en proceso de construccion es la Central Hidroelectrica La Yesca, el cual concluira a finales de 2012 y consiste en dos generadores electricos de 375 MW, 17 kV. Sera el segundo en potencia y el tercero en generacion electrica en el sistema. De acuerdo con las normas nacionales e internacionales, debe efectuarse un conjunto de pruebas estaticas y dinamicas en estos generadores antes de la puesta en servicio, para asegurar su operacion apropiada. La prueba de resistencia de alto voltaje del devanado del estator, la prueba de corto circuito subito trifasico y el calculo de eficiencia energetica son algunas de las pruebas mas importantes por realizar en un nuevo generador electrico. Estas pruebas son dificiles de efectuar en sitio debido a la capacidad del equipo requerido, por lo que muy pocas companias en el mundo pueden conducirlas.

  17. Development of children male virtual simulator of 15 years old using anatomic parameters of ICRP number 89; Desenvolvimento de um simulador pediatrico virtual masculino de 15 anos com base nos parametros anatomicos da ICRP de numero 89

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Erick da S.; Junior, Alberico B. de C.; Tavares, Paulo V. dos S. [Universidade Federal de Sergipe (UFSE), Sao Cristovao, SE (Brazil)

    2016-07-01

    Computational dosimetry is engaged in radiation dose estimate received by an individual exposed to a radiation field and evaluates the cancer risk associated with this type of exposure. To perform such an assessment is used virtual simulators representing humans. Currently, with the development of graphic animation software, the development of these simulators was facilitated using only knowledge of human anatomy to prepare various types of simulators (man, woman, child and baby) in various positions (sitting, standing, running) or part thereof (head, trunk and limbs). In this project, we built a virtual boy 15 years in mesh and voxels to dare in computational dosimetry. (author)

  18. Development of a remote monitoring system, through monitoring of key safety parameters for a nuclear research reactor; Desarrollo de un sistema de vigilancia remota, por medio del monitoreo de parametros claves de seguridad, para un reactor nuclear de investigacion

    Energy Technology Data Exchange (ETDEWEB)

    Urcia, Agustin; Arrieta, Rolando [Direccion de Produccion, Instituto Peruano de Energia Nuclear, Lima (Peru); Baltuano, Oscar; Chan, Renzo [Direccion de Investigacion y Desarrollo, Instituto Peruano de Energia Nuclear, Lima (Peru); Tincopa, Jean Pierre [Facultad de Ingenieria Electrica y Electronica, Universidad Nacional del Callao, Callao (Peru); Urquizo, Rafael [Facultad de Ingenieria Electronica, Universidad Tecnologica del Peru, Lima (Peru); Rosas, Bernick [Facultad de Ingenieria Electronica, Universidad Nacional de Ingenieria, Lima (Peru)

    2014-07-01

    This paper presents the detailed development, installation and commissioning of water level sensors and exposure rate range in the 11 meters level (mouth of tank) of the RP-10 nuclear reactor used to continuously monitor these values and use them as security for the periods of no presence of operating personnel (overlooking situation) with the reactor in shutdown state. The levels of these parameters are packaged and transmitted to a controller in the control room of reactor for display and activation of alarm levels. Additionally, the design of these warning signs is shown in conjunction with the fire alarm in the building of reactor and auxiliary laboratories to be transmitted to the physical security facility, located at a distance of 500 meters. (authors).

  19. Correlations Between retention indices and molecular structure of aliphatic alcohols and of their benzoyl derivatives on phenyl substituted polysiloxane stationary phases; Cromatografia en fase gaseosa sobre metilfenilpolisiloxanos. Estructura molecular y parametros de retencion para alcoholes y sus derivados benzoilados

    Energy Technology Data Exchange (ETDEWEB)

    Pias, J B; Gasco, L

    1976-07-01

    The retention indices of aliphatic alcohols of carbon number up to C{sub g}, and of their benzoyl derivatives up to C{sub 7}, were determined in columns packed with Chromo sorb G (AW-DMCS-HP) coated previously with 5% methyl, and methyl phenyl polysiloxanes with increasing polarity (SE-30, 0V-3, 0V-7, 0V-11, 0V-17 and OV-25). Correlations between retention indices and chain length for 1-alcohols, 2-alcohols, 3-alcohols, 1 , on -3-alcohols, 2-methyl-1-alcohols and for their corresponding benzoyl derivatives were calculated at 100, 120 and 140 degree centigree. In alcohols, a -CH{sub 2}- group increases I approximately 100 units, and in their benzoyl derivatives from 80 to 100 units. Dispersion indices {delta}l , and positional and structural increments {delta}I, were evaluated for -OH and benzoyl groups in terms of phase polarity and chain length. Effects of chain length, chain branching and double bond location on retention parameters were also studied. (Author) 23 refs.

  20. High temperature flow behaviour of SiC reinforced lithium

    Indian Academy of Sciences (India)

    The compressive flow behaviour of lithium aluminosilicate (LAS) glass, with and without SiC particulate reinforcements, was studied. The LAS glass crystallized to spodumene during high-temperature testing. The flow behaviour of LAS glass changed from Newtonian to non-Newtonian due to the presence of crystalline ...

  1. Cationic flotation of some lithium ores

    International Nuclear Information System (INIS)

    Valadao, G.E.S.; Peres, A.E.C.; Silva, H.C. da

    1984-01-01

    The cationic flotation of some lithium ores (spodumene, amblygonite, petalite, lepidolite) is studied by the measure of zeta potential and micro-flotation tests in Hallimond tube. The effect of some modifier agents (corn starch, meta sodium silicate) on the lithium flotation is studied. (M.A.C.) [pt

  2. Influence of the brazing parameters on microstructure and mechanical properties of brazed joints of Hastelloy B2 nickel base alloy; Influencia de los parametros de soldeo fuerte en la microestructura y propiedades mecanicas de la union de la aleacion base niquel Hastelloy B2

    Energy Technology Data Exchange (ETDEWEB)

    Sotelo, J. C.; Gonzalez, M.; Porto, E.

    2014-07-01

    A study of the high vacuum brazing process of solid solution strengthened Hastelloy B2 nickel alloy has been done. A first stage of research has focused on the selection of the most appropriate brazing filler metal to the base material and vacuum furnace brazing process. The influence of welding parameters on joint microstructure constituents, relating the microstructure of the joint to its mechanical properties, has been evaluated. Two gaps of 50 and 200 micrometers, and two dwell times at brazing temperature of 10 and 90 minutes were studied. The braze joint mainly consists of the nickel rich matrix, nickel silicide and ternary compounds. Finally, the results of this study have shown the high bond strength for small gaps and increased dwell times of 90 minutes. (Author)

  3. Measurement of the dosimetric parameters for low monitor units in step-and-shoot IMRT delivered by Siemens Artiste linear accelerators; Medida de los parametros dosimetricos para bajo numero de unidades monitor en IMRT segmentada estatica administrada por aceleradores lineales Siemens Artiste

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Rodriguez, C.; Lopez Fernandez, A.; Saez Beltran, M.; Martin Martin, G.; Alonso Iracheta, L.

    2012-07-01

    Absorbed dose linearity and beam stability, both for low monitor units, are important factors for ensuring planned dose delivery in step-and-shoot IMRT. For Siemens Artiste linear accelerators, under IMRT stable irradiation conditions and for a single segment of 20 cm x 20 cm field size, the linearity of the absorbed dose with the monitor units, field flatness and symmetry have been measured for the range between 1 and 10 monitor units. We have found that absorbed dose linearity with monitor units is within 2% down to 2 monitor units and it is about 9% for 1 monitor unit. Flatness and symmetry values show variations within 1% down to 2 monitor units and increase by 9% for lower values. Using our monitor unit distribution per segment in IMRT we estimate that the uncertainty in absorbed dose for a whole treatment due to these factors is less than 1% (k= 3). (Author) 13 refs.

  4. Application of the probe Horiba U-23 in the analysis of physical-chemical parameters of groundwater influences on the Osamu Utsumi uranium mine in Caldas-MG; Aplicacao da sonda Horiba U-23 na analise de parametros fisico-quimicos das aguas subterraneas sobre influencia da mina de uranio Osamu Utsumi em Caldas-MG

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Flavio H.S., E-mail: flaviohsmoreira2@gmail.com [Universidade Federal de Alfenas (UNIFAL), Pocos de Caldas, MG (Brazil); Alberti, Heber L.C.; Silva, Nivaldo C., E-mail: heber@cnen.gov.br, E-mail: ncsilva@cnen.gov.br [Comissao Nacional de Energia Nuclear (LAPOC/CNEN-MG), Pocos de Caldas, MG (Brazil). Laboratorio de Pocos de Caldas; Fleming, Peter Marshall, E-mail: pmf@cnen.gov.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, BH (Brazil)

    2013-07-01

    This study presents data on the analysis of physical-chemical parameters of groundwater in the uranium mine Osamu Utsumi, belonging to the Industrias Nucleares do Brasil - INB, in the municipality of Caldas. This work is part of the team responsible for the evaluation of Plano de Recuperacao de Areas Degradadas (PRAD), team consists of researchers from Laboratorio de Pocos de Caldas - LAPOC and of the Centro de Desenvolvimento Tecnologico Nuclear - CDTN, units of the Comissao Nacional de Energia Nuclear - CNEN. Sampling was carried out in eleven wells in the 'bota-fora 4' area and digs mine. Analyses of groundwater quality were performed using the multiparameter probe Horiba U23, recent acquisition of LAPOC. The results characterize the groundwater of ten wells monitored as acidic and with a high electrical conductivity, due to the impacts caused by drainage Mining Acid (DAM)

  5. Statistic analysis of grouping in evaluation of the behavior of stable chemical elements and physical-chemical parameters in effluent from uranium mining; Analise de agrupamento na avaliacao do comportamento de elementos quimicos estaveis e parametros fisico-quimicos em efluente de mineracao de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Wagner de S., E-mail: wspereira@inb.gov.br, E-mail: pereirarsj@gmail.com [Universidade Federal Fluminense (GETA/LARARA-PLS/UFF), Niteroi, RJ (Brazil). Grupo de Estudos em Temas Ambientais. Laboratorio de Radiobiologia e Radiometria Pedro Lopes dos Santos; Py Junior, Delcy de A.; Dores, Luis A. de C.B.; Campelo, Emanuele L.C.; Morais, Gustavo F. de; Kelecom, Alphonse, E-mail: delcy@inb.gov.br, E-mail: kclecom@uol.com.br [lndustrias Nucleares do Brasil (UTM/INB), Pocos de Caldas, MG (Brazil). Unidade de Tratamento de Minerios; Pereira, Juliana R. de S., E-mail: pereirarsj@gmail.com [Universidade Federal de Alfenas, Pocos de Caldas, MG (Brazil)

    2013-10-01

    The Ore Treatment Unit (UTM) is a uranium mine off. The statistical analysis of clustering was used to evaluate the behavior of stable chemical elements and physico-chemical variables in their effluents. The use of cluster analysis proved effective in the evaluation, allowing to identify groups of chemical elements in physico-chemical variables and group analyzes (element and variables ). As a result, we can say, based on the analysis of the data, a strong link between Ca and Mg and between Al and TR{sub 2}O{sub 3} (rare earth oxides) in the UTM effluents. The SO{sub 4} was also identified as strongly linked to total solids and dissolved and these linked to electrical conductivity. Other associations existed, but were not as strongly linked. Additional collections for seasonal evaluation are required so that assessments can be confirmed. Additional statistics analysis (ordination techniques) should be used to help identify the origins of the groups identified in this analysis. (author)

  6. Overvoltage in chain of insulators front to lightning discharges: a comparative study of the calculation methods and of the parameter Z{sub t}; Sobretensoes em cadeia de isoladores frente a descargas atmosfericas: um estudo comparativo dos metodos de calculo e do parametro Z{sub t}

    Energy Technology Data Exchange (ETDEWEB)

    Godoy, Antonio Varejao de

    1989-07-01

    This work studies in a deterministic point of view a lightning discharges that strikes directly the transmission line tower top. The calculation methods of this kind of surges: the method of successive reflections introduced by Jordan and the method of field well as compared with these purpose. Based on this two approaches a computational program is developed to calculate the overvoltage on the insulator string and the required parameters. Based on the results of this analysis, the simplest and most efficient method is chosen and where a simple sensitivity analysis is made for the following parameters: the impedance of lightning stroke channel, the tower foot impedance, time to crest of stroke shape function and tower surge impedance. This analysis is performed in order to verify the voltage variation on the insulator string. Finally, the last parameter, the tower surge impedance is emphasized comparing its calculated values with the measured values by geometrical model technique. (author)

  7. Variability in the contouring of the heart in treatments with radiotherapy in cancer of breast left and its influence on parameters of decision; Varibilidad en el contorneo del corazon en tratamientos con radioterapia en cancer de mama inquierda y su influencia en parametros de decision

    Energy Technology Data Exchange (ETDEWEB)

    Manchado de Sola, F.; Reyes Garcia, A.; Munoz Carmona, D. M.; Bayo Lozano, E.; Sanchez Segovia, J.

    2013-07-01

    The objective of this work is to study the variability in the contouring of the heart by our TERT and compare with the contouring done by a radiologist specialist as well as influence in the dosimetry of the organ of risk and its influence in the decision-making process in accepting a planning. (Author)

  8. Dosimetric quality of postal kit used for evaluation in IRD/CNEN of radiation protection parameters in dental radiology in the State of Rio de Janeiro; Qualidade dosimetrica do kit postal utilizado pelo IRD/CNEN para a avaliacao dos parametros de radioprotecao em radiologia odontologica no Estado do Rio de Janeiro

    Energy Technology Data Exchange (ETDEWEB)

    Coutinho, Soray Abbud; Mota, Helvecio C; Dovales, Ana Cristina M [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil). Dept. de Fisica Medica

    2001-07-01

    This work shows the results of a comparison between the skin entrance doses determined using an ionization chamber or a postal kit routinely used for the evaluation of radiation protection parameters in dental radiology in the state of Rio de Janeiro. By using the dosimetric kit, entrance skin dose is determined from two thermoluminescent dosimeters (TLDs) - previously calibrated in a {sup 137} Cs source - by using calibration factors determined in TLDs irradiated in air, on a water phantom and on an aluminium filter. The correspondence between the doses obtained with different methods was evaluated for three different X-ray spectra as radiation source. Results indicate that calibration factors used are adequate and that the kit has enough sensibility and reproducibility, measuring properly the skin entrance dose in dental X-rays. (author)

  9. Statistical analysis in the design of nuclear fuel cells and training of a neural network to predict safety parameters for reactors BWR; Analisis estadistico en el diseno de celdas de combustible nuclear y entrenamiento de una red neuronal para predecir parametros de seguridad para reactores BWR

    Energy Technology Data Exchange (ETDEWEB)

    Jauregui Ch, V.

    2013-07-01

    In this work the obtained results for a statistical analysis are shown, with the purpose of studying the performance of the fuel lattice, taking into account the frequency of the pins that were used. For this objective, different statistical distributions were used; one approximately to normal, another type X{sup 2} but in an inverse form and a random distribution. Also, the prediction of some parameters of the nuclear reactor in a fuel reload was made through a neuronal network, which was trained. The statistical analysis was made using the parameters of the fuel lattice, which was generated through three heuristic techniques: Ant Colony Optimization System, Neuronal Networks and a hybrid among Scatter Search and Path Re linking. The behavior of the local power peak factor was revised in the fuel lattice with the use of different frequencies of enrichment uranium pines, using the three techniques mentioned before, in the same way the infinite multiplication factor of neutrons was analyzed (k..), to determine within what range this factor in the reactor is. Taking into account all the information, which was obtained through the statistical analysis, a neuronal network was trained; that will help to predict the behavior of some parameters of the nuclear reactor, considering a fixed fuel reload with their respective control rods pattern. In the same way, the quality of the training was evaluated using different fuel lattices. The neuronal network learned to predict the next parameters: Shutdown Margin (SDM), the pin burn peaks for two different fuel batches, Thermal Limits and the Effective Neutron Multiplication Factor (k{sup eff}). The results show that the fuel lattices in which the frequency, which the inverted form of the X{sup 2} distribution, was used revealed the best values of local power peak factor. Additionally it is shown that the performance of a fuel lattice could be enhanced controlling the frequency of the uranium enrichment rods and the variety of the gadolinium rods used in the design. In the same way we can prove that we could predict the behavior of a fuel reload using a training neuronal network for this purpose. (Author)

  10. Survey of nuclear parameters from the TRIGA Mark I IPR R1 Brazilian reactor with concentric configuration aiming the application of K{sub 0} neutron activation technique; Levantamento de parametros nucleares do reator TRIGA Mark I IPR R1 com configuracao concentrica visando a aplicacao da tecnica de ativacao neutronica K{sub 0}

    Energy Technology Data Exchange (ETDEWEB)

    Franco, Milton Batista

    2006-07-01

    This research intended to determine the nuclear parameters a, f, spectral index and neutron temperature in several irradiations positions of the TRIGA Mark 1 IPR-R1 reactor, for use on the parametric method K{sub 0} in the CDTN. K{sub 0} is a monostandard method of neutron activation analysis. It is, on the whole, experimentally simple, flexible and an important tool for accurate and convenient standardization in instrumental multi-element analysis. At the time the parameters were determined at the rotatory rack, lower layer and in the central thimble: alpha was calculated applying the three bare monitor method using {sup 197}Au, {sup 94}Zr and {sup 96}Zr; f determination was done according to the bare bi-isotopic method; neutron temperature was calculated through the direct method using {sup 176}Lu, {sup 94}Zr, {sup 96}Zr and {sup 197}Au and the Westcott's g(Tn) function for the {sup 176}Lu was calculated and the result was interpolated in the Grintakis and Kim (1975) Table, determining the neutron temperature. The procedure to check the parameters consisted in using standard solutions of Au (metal foil, NBS), Lu (LuO{sub 2}, Johnson Mattey Company - JMC) and Zr (ZrO{sub 2} and metal foil, Johnson Mattey Company 99,99% and Zry - 4: 98,14% of Zr, National Bureau of Standard- NBS). Several certified reference materials and two samples of intercomparisons (samples of sediment of the IAEA/ARCAL XXVI project) have been analysed by means of k{sub 0}- INAA in order to verify the efficiency of the method and the quality of the parameters. The certified reference materials were: GXR-2, GXR-5 and GXR-6 of the United States Geological Survey (USGS) and Soil-5, Soil-7 and SL-1 of the International Atomic Energy Agency (IAEA). (author)

  11. Determination of the dose of gamma radiation sterilization for assessment of biological parameters of male Ceratitis capitada (Diptera: Tephritidae), tsl - Vienna 8 strain; Determinacao da dose de radiacao gama esterilizante pela avaliacao dos parametros biologicos de machos de Ceratitis capitata (Diptera: Tephritidae), linhagem tsl - Vienna 8

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Aline Cristina Pereira da

    2011-07-01

    The Vienna-8, tsl (temperature sensitive lethal) strain of Ceratitis capitata, by presenting mutations that facilitate the mass rearing and release only of sterile males in the field, has been used in (Sterile Insect Technique) programmes. The objective of this study was to determine the radiation dose that provides the highest level of sterility for Vienna-8, tsl males assessing their biological parameters that indicate the quality of sterile males to be released. Brown pupae (males) of the tsl strain were obtained from the mass rearing of the Food Irradiation and Radio entomology laboratory of CENA/USP, and they were irradiated (with gamma radiation - {sup 60}Co) 24 hours before the emergence at rates of 0, 30, 60, 90 and 120 Gy. The determination of the sterilizing dose was based on fertility of sexually mature females of the bisexual strain and not irradiated, mated with males of different treatments. Eggs were collected daily during 6 days, were counted and it was possible to estimate fecundity, and assess the hatching rate. The emergence and flight ability were determined by following the protocol of quality control manual for FAO/IAEA/USDA (2003). To assess the longevity under nutritional stress, the insects were kept a period of 48 h after emergence in the absence of water and food, and after this period, mortality was recorded. The size of the testes (left and right) was obtained by dissecting irradiated and non-irradiated males at the eighth day of life, and measure the testes in an ocular micrometer, considering the maximum length and width of each sample. To determine the sperm number was necessary to dissect the males and break their testicles. No difference was observed in emergence rate, flight ability and longevity of irradiated and non-irradiated males, nor in the fecundity of females mated with males of different treatments. The sterilizing dose that resulted in lower fertility of females was 120 Gy, with 1.5% hatching. Considering the parameters of emergence, flight ability, longevity under stress and sterility recommended for the sterile insect technique which consists of approximately 99%, the sterilizing dose to be used is 120 Gy. The size of the testes and the sperm number were affected by radiation. Males irradiated with 120 Gy presented a reduction about 25% in size of the testes, compared with the control (0 Gy). The testes of normal males contained an average of 41.910 sperm, and this value was decreased by increasing the dose of radiation, so that males irradiated with 120 Gy had a median of 27.921 sperm, and this allowed to recommend the use of GM male to control C. capitata. (author)

  12. Inference of some pharmacokinetic parameters of the C mitomycin, through the analysis of its micro nucleate polychromatic erythrocytes induction kinetics; Inferencia de algunos parametros farmacocineticos de la mitomicina C, mediante el analisis de su cinetica de induccion de eritrocitos policromaticos micronucleados

    Energy Technology Data Exchange (ETDEWEB)

    Morales R, P.; Vallarino K, T.; Cruz V, V.; Delgadillo H, A. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2003-07-01

    The objective of the present work was to establish pharmacokinetic parameters of the C Mitomycin (MMC) in vivo, comparing its kinetics of induction of polychromatic micro nucleate erythrocytes (EPGMN) with that of the gamma radiation. The used doses were of 0.75; 1.5 and 3. 0 {mu}moles/kg of MMC. It was observed that the MMC produces MN in the first cycle of cellular division and it is independent of the cytotoxic effect. This agent requires of a relatively long period of latency that is not compatible with her great reactivity, for what the pharmacokinetic values obtained in fact reflect the time that takes the processing of leisure in the DNA and the subsequent induction of ruptures that produce MN. (Author)

  13. The determination of maturity levels in source rocks of the La Luna Formation, Maracaibo Basin, Venezuela, based on convention geochemical parameters and asphaltenes; Determinacao do grau de maturacao em rochas geradoras de petroleo, formacao La Luna, Bacia de Maracaibo, Venezuela: parametros geoquimicos convencionais e asfaltenos

    Energy Technology Data Exchange (ETDEWEB)

    Castro, L.P. de [Pontificia Universidade Catolica (PUC-RS), Porto Alegre, RS (Brazil). Centro de Excelencia em Pesquisas sobre o Armazenamento de Carbono; Franco, N. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Dept. de Geologia; Lopez, L.; Lo Monaco, S.; Escobar, G. [Universidad Central de Venezuela (UCV), Caracas (Venezuela); Kalkreuth, W. [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Centro de Excelencia em Analises de Carvao e Rochas Geradoras de Petroleo

    2008-07-01

    The La Luna Formation, main source rock of the Maracaibo Basin was studied by conventional geochemical parameters, used to determine the maturity, and they were compared with the physic-chemical and molecular properties of the asphaltenes present in the bitumen of the rocks. Three wells were studied (A, B and C) with a total of 13 samples. Based on Rock-Eval results the organic matter in well A (455 deg C Tmax) shows a relatively high level of maturation (top of the oil window), whereas the organic matter in well B (435 - 436 deg C Tmax) is in the beginning of the oil window. Tmax values in well C (438 - 446 deg C) and well C suggest an intermediate maturity level. The biomarkers identified in well B and C show ratios indicating an equilibrium state in the maturity level. A good correlation was found comparing the conventional analytical data with the determination of maturity level obtained from the asphaltenes precipitated from the bitumen of the samples. With increased maturity levels the H1 NMR analysis showed enrichment in aromatic molecules in relation to aliphatic, due to the bitumen aromatization process. Similarly, the asphaltenes molecular weight has higher values in samples characterized by elevated maturity levels. This confirms earlier studies that showed that asphaltenes may be utilized as maturity parameter of organic matter. (author)

  14. Comparative study of the parameters associated with quality control and absorbed dose in linear accelerators with (FF) and without (FFF) flattening filter; Estudo comparativo dos parametros associados a dose absorvida e controle de qualidade em aceleradores lineares com filtro aplainador (FF) e sem filtro aplainador (FFF)

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Anderson Sorgatti de

    2017-11-01

    Teletherapy, radiation therapy with linear accelerators, for cancer treatment has being used for years with good clinical results.Since the 90's the removal of the flattening filter, item placed at the gantry of the machine, has shown better results for the treatment of some cancers thus being extensively studied. Treatments with Intensity Modulated Radiotherapy (IMRT) and Stereotaxic Radiotherapy (SRT) were more efficient without the flattening filter. Varian Oncology released the TrueBeam in 2012, a accelerator capable of operating with or without the flattening filter. The aim of this work is to access homogeneity of the percentage depth dose (PDP) and beam quality index (TPR20/10), two important parameters used in patient dose calculations. The data used for analysis were obtained with the Israelita Albert Einstein Hospital (HIAE), Real Portugues Hospital (RHP) and 3 more institutions located in the United States. The statistical data analysis allowed to observe the parameters behaviors. In general, they were very homogeneous, with errors smaller than 1% confirming the conformance of the TrueBeam accelerators. (author)

  15. Improvement of the obtention process of {sup 131} I of ININ through studies of equipment design and process parameters fitting in the simulator; Perfeccionamiento del proceso de obtencion del {sup 131} I del ININ mediante estudios de diseno del equipo y ajustes de parametros del proceso en el simulador

    Energy Technology Data Exchange (ETDEWEB)

    Zepeda M, M C

    2006-07-01

    The main objective of the work was to achieve a high yield of the reaction that happens among the vapors of {sup 131} I and the NaOH to obtain sodium iodide (Na{sup 131} I) in solution optimizing the contact time of the molecules in gaseous state of {sup 131} I with the NaOH molecules through the bubbling velocity of the {sup 131} I in the solution of NaOH 0.1 N, as well as the operation temperature during the distillation process by dry via starting from tellurium dioxide (TeO{sub 2}) with the purpose of that the {sup 131} I that is obtained in the form of Na{sup 131} I solution presents the necessary quality that allows to distribute it in the market. The particular objectives were: a) To improve the distillation equipment used for the obtaining of {sup 131} I starting from irradiated tellurium dioxide redrawing the dilution system with the purpose of recovering the {sup 131} I in a minimum volume of sodium hydroxide (NaOH). b) To achieve a bigger time of contact among the molecules of {sup 131} I in gaseous state with the molecules of NaOH in solution through the bubbling velocity and of the redrawing of the dilution system. c) To implement the production of {sup 131} I by dry distillation via starting from tellurium dioxide, obtaining it with a high radionuclide and radiochemical purity. d) To obtain {sup 131} I with the necessary specifications that it marks the pharmacopoeia and it can be used with medical ends. (Author)

  16. Fundamental hematological parameters in peripheral blood of inhabitants from zones affected by the Chernobyl accident, who have received medical attention in Cuba; Principales parametros hematologicos en sangre periferica de pobladores de zonas afectadas por el accidente de chernobil que recibieron asistencia medica en Cuba

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, O; Cardenas, J; Valdes, M [Centro de Proteccion e Higiene de las Radiaciones, La Habana (Cuba)

    1994-12-31

    The fundamental hematological parameters in peripheral blood of 2537 children from 409 Ukrainian localities were studied to evaluate the radiological impact produced by the accident. The hematological analyses were performed as part of the ordinary program of medical examination. The results were grouped taking into account the superficial contamination levels by {sup 137C}s of the zones where the infants came from.

  17. A model for transmission lines through state equations for the effect of frequency on the longitudinal parameters: inclusion and analysis of corona effect; Uma modelagem para linhas de transmissao por meio de equacoes de estado considerando o efeito da frequencia sobre os parametros longitudinais: inclusao e analise do efeito corona

    Energy Technology Data Exchange (ETDEWEB)

    Costa, E.C.M.; Wedy, G.F.; Kurokawa, S.; Prado, A.J.; Bovolato, L.F. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Ilha Solteira (Brazil). Fac. de Engenharia Eletrica. Depto. de Engenharia Eletrica], e-mail: kurokawa@dee.feis.unesp.br; Pissolato, J. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Eletrica e de Computacao. Depto. de Sistemas e Controle de Energia], email: pisso@dsce.fee.unicamp.br

    2009-07-01

    This paper proposes the inclusion of corona effect on modeling of transmission lines taking into account the effect of frequency on the longitudinal parameters. This paper aims to present a model with acceptable accuracy and easy to implement in the simulation of transients due to corona. To modelling the effect corona is used the Skilling-Umoto model and to reproduce the distributed nature of the line parameters is applied cascade circuits {pi}. The differential equations that represent the electromagnetic transients along the line are presented in state of space and solved using the trapezoidal numerical integration method (trapezoidal rule). The line parameters, obtained using Bessel equations and Carson's infinite series, are reproduced in an approximate way through a rational function F {omega} and then inserted into the cascade circuit {pi}. Finally, simulations are carried out using constant parameters and variable depending on the frequency with scope to check and measure the differences between the methodologies. This work also presents a comparison between data obtained through simulation and empirical data.

  18. A numerical study of natural hydrate formation kinetics in petroleum pipelines by the phase field method: influence of the model parameters; Estudo da cinetica de formacao de hidratos em dutos de petroleo pelo metodo do campo de fase: influencia dos parametros do modelo

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Mabelle Biancardi; Castro, Jose Adilson de; Silva, Alexandre Jose da; Ferreira, Alexandre Furtado [Universidade Federal Fluminense (UFF), Volta Redonda, RJ (Brazil). Pos-Graduacao em Engenharia Metalurgica], e-mail: mabelle@metal.eeimvr.uff.br, e-mail: adilson@metal.eeimvr.uff.br, e-mail: ajs@metal.eeimvr.uff.br, e-mail: furtado@metal.eeimvr.uff.br

    2006-07-01

    The objective of this work is to study the influence of the parameters of the phase field model field on the formation of natural hydrates. It was investigated parameters such as superficial tension, effect of the super-cooling, homogeneous and heterogeneous nucleation. The influence of these parameters was analyzed according to morphology of the interface and the rate of formation. The mathematical model to describe the evolution of the natural hydrates formation is based on the simultaneous solution of the phase and energy equations. The finite volume numerical method was used to discretize the governing differential equations. Results of the simulation indicated that the reduction of the superficial tension leads to the increase of the surface rugosity, interface thickness and instability of the interface resulting in a decrease of the rate growth. In order to investigate the nucleation effect of the natural hydrates, two conditions had been simulated a) the random distribution of nuclei: where the evolution of formed hydrates suffered coalescence and the kinetic decreased due to impingement of hydrates regions and b) Nucleation in the pipeline wall, where rough interfaces were observed. (author)

  19. Survey of shielding calculation parameters in radiotherapy rooms used in the country and its impact in the existing calculation methodologies; Levantamento de parametros de calculos de blindagem de salas de radioterapia utilizados no pais e seu impacto nas metodologias de calculo existentes

    Energy Technology Data Exchange (ETDEWEB)

    Japiassu, Fernando Parois

    2013-07-01

    When designing radiotherapy treatment rooms, the dimensions of barriers are established on the basis of American calculation methodologies specifically; NCRP Report N° 49, NCRP Report N° 51, and more recently, NCRP Report N° 151. Such barrier calculations are based on parameters reflecting predictions of treatments to be performed within the room; which, in tum, reftect a specific reality found in a country. There exists, however, a variety of modern radiotherapy techniques, such as Intensity Modulated Radiation Therapy (IMRT); Total Body Irradiation (TBl) and radiosurgery (SRS); where patierits are treated in a much different way than during more conventional treatrnents, which are not taken into account the traditional shielding calculation methodology. This may lead to a faulty design of treattnent rooms. In order to establish a comparison between the methodology used to calculate shielding design and the reality of treatments performed in Brazil, two radiotherapy facilitie were selected, both of them offering traditional and modern treatment techniqued as described above. Data in relation with reatments perfotmed over a period of six (6)months of operations in both institutions were collected. Based on tlis informaton, a new set of realistic parameters required for shielding design was estãblished, whicb in turn allowed for a nwe caculation of barrier thickness for both facilities. The barrier thickness resultaing from this calculation was then compared with the barrier thickness propose as part of the original shielding design, approved by the regulatory authority. First, concerning the public facility, the thickness of all primary barriers proposed in the shielding design was actually larger than the thickness resulting from calculations based on realistic parameters. Second, concerning the private facility, the new data show that the thickness of three out of the four primary barriers described in the project is larger than the thickness oresulting from calculation based on current operating conditions. When it comes to thickness of secondary barriers, calculations based on averages of treatments over six months show results below the proposed thicknesses in the shielding design of the public facility. However, data reflecting the most extreme situations observed in routine operations how that the thickness proposed in the design project does not meet hielding requirements. In the private facility, more conservative estimates were used in the shielding design, which resultedin suitable barrier thickness in both normal and extreme operation conditions. In fact, the actual barrier thicknesis in average 31 cm greater than the ehickness required by the reality-based data. The primary barrier thickness resulting from reality-based calculations supports the assumption than smaller primary barrier thickness is required in facilities using modern techniques of radiation therap, as opposed to thickness requirements in facilities that only uses conventional treatment techniques. The hypothesis of increased thickness requirements for secondary barriers of installations using IMRT was confirmed by data obtained from the public facility. The results obtained from the private facility denote that the addition of conservative factors in the calculation method will produce barriers suitable for both average and extreme conditions of accelerator usage. However, corresponding increased costs must also be considered. (author)

  20. Effect of the delay in olive processing after harvesting on some physicochemical and nutritional parameters of olive oil from the Racimilla variety; Influencia del retraso en el procesado de las aceitunas tras la recoleccion, en parametros fisico-quimicos y nutricionales de aceite de oliva de la variedad Ramicilla

    Energy Technology Data Exchange (ETDEWEB)

    Benito, M.; Oria, R.; Sanchez-Gimeno, A. C.

    2009-07-01

    The aim of this work was to study how the delay time between harvesting and processing affects the physicochemical and nutritional parameters of Racimilla olive (Olea europaea L.) oil. The physicochemical parameters (titratable acidity, peroxide value, coefficients of specific extinction and pigments content) changed remarkably. The nutritional parameters such as fatty acids profile, total phenols and vitamin E also suffered a change with the delay in processing. Physicochemical and nutritional parameter modifications were detrimental to olive oil quality. In conclusion, a delay in processing after harvesting is not efficient to preserve the physicochemical and nutritional quality of the olive oil from the Racimilla variety. (Author) 21 refs.

  1. Correlation of nodular austempered ductile iron (ADI) microstructural parameters and fatigue properties using an approach based on fracture mechanics; Correlacao entre parametros microestruturais do ferro fundido nodular austemperado (ADI) com suas propriedades a fadiga utilizando uma abordagem baseada na mecanica de fratura

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Jose Felipe [Universidade de Itauna (UIT), MG (Brazil). Faculdade de Engenharia; Fonseca, Vinicius Rizzuti; Godefroid, Leonardo Barbosa [Universidade Federal de Ouro Preto (UFOP), MG (Brazil). Escola de Minas; Ribeiro, Gabriel de Oliveira [Universidade Federal de Minas Gerais (UFMG), MG (Brazil). Departamento de Engenharia de Estruturas

    2010-07-01

    An investigation has been accomplished to check the effect of temperature and austempering time on austempered ductile iron (ADI) properties by means of fracture toughness (K{sub C}) and fatigue threshold (∆K{sub th}) tests. The correlation of ADI microstructural parameters and ADI two mechanical parameters: KC and Kth, is evaluated. Three sets of samples have ben extracted from ADI casting Y blocks produced in industrial conditions.and austenitized at 900°C for 1.5 hour. The austempering process has been performed in the following ways: the first set was austenitized at 300 deg C for 4 hours, the second set at 360°C for 1.5 hour and the third at 360°C for 0.6 hour. These distinct austempering processes have been adopted in order to obtain distinct microstructures containing austenite with two different carbon rates and two ferritic cell sizes. The materials have been characterized by means of optical and electronic microscopy, X-ray diffraction and mechanical tests. All materials have presented equivalent fatigue crack propagation rates, fracture toughness in the range between 94 and 128 MPa·m{sup 1/2} and ∆K{sub th} in the range between 5,7 and 6,4 MPa·m{sup 1/2}. The experimental results have confirmed the effect of microstructural properties (austenitic volumetric rate, austenitic carbon rate, ferritic cell size, total matrix carbon content) on fracture toughness (K{sub C}) and fatigue threshold (∆K{sub th}). Further, it was found that following parameters: fracture toughness (K{sub C}), fatigue threshold ((∆K{sub th}) and impact strength are correlated with the total matrix carbon content and ferritic cell size. (author)

  2. Inference from some pharmacokinetic and pharmacodynamic parameters of busulfan through the analysis of its induction kinetics of micronuclei polychromated erythrocytes; Inferencia de algunos parametros farmacocineticos y farmacodinamicos de busulfan, mediante el analisis de su cinetica de induccion de eritrocitos policromaticos micronucleados

    Energy Technology Data Exchange (ETDEWEB)

    Lopez I, M.R.; Vallarino K, T.; Morales R, P. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2001-07-01

    The induction kinetics of micronuclei polychromated eritrocites (EPC-MN) which is produced by busulfan and compared with that produced by the ionizing radiation, allows to make inferences over the pharmacokinetics and pharmacodynamics of busulfan. Observing two induction mechanisms of MN, this one early at low doses and other later at high doses, this last is presented to a critical dose being very sheer and associated with an increase of the cytotoxicity. The data suggest the transformation or dependence between these two types of leisures, which to determine the narrow therapeutical margin of busulfan. The pharmacokinetic parameters determined in the early mechanisms kinetics indicate a latency period, a time of effective activity and of half life 5.7, 5.2 and 2.6 h respectively. (Author)

  3. Classification and methods of calculation of parameters ETFM/MRO de CN Cofrentes by subject to uncertainty IS-32; Clasificacion y metodologia de calculo de los parametros de ETFM/MRO de CN Cofrentes sujetos a incertidumbres segun la IS-32

    Energy Technology Data Exchange (ETDEWEB)

    Kaychouhi, A.; Mota, M.; Uribes, O.; Lora, C.

    2014-07-01

    This paper aims to show the development of the methodology of NPP Cofrentes has been used in the preparation, evaluation, analysis and calculations of uncertainty applied to the values of the parameters of category 2 and 3 of the Improved Operating Technical Specifications. (Author)

  4. Methodology of assessment of the impact on the risk of changes of monitoring requirements of safety equipment integrating treatment and analysis of uncertainty of model and parameter; Metodologia de evaluacion del impacto en el riego de cambios de requisitos de vigilancia de equipos de seguridad integrando tratamiento y analisis de incertidumbres de modelo y parametros

    Energy Technology Data Exchange (ETDEWEB)

    Martorell, S.; Villamizar, M.; Marton, I.; Villanueva, J. f.; Carlos, S.; Sanchez, A. I.

    2013-07-01

    The feasibility of the proposed methodology has been demonstrated with the results obtained in a case of application for the analysis of changes in the requirements of maximum time of unavailability of system batteries using an APS level 1. The proposed methodology is consistent with the proposal by the American regulatory guide RG 1,174, applicable to LWR designs in Spanish, although large plants their level of technical development.

  5. Mechanism of Prototropy. V. Arrhenius parameters of the tautomerization of Benzylidene Benzylamine and its {alpha}-{alpha}-alkyl derivatives; Mecanismo de la prototropia V. Parametros de Arrhenius de la toutomerizacion de benciliden-bencilamina y sus {alpha}- y {alpha}-alquilderivados

    Energy Technology Data Exchange (ETDEWEB)

    Perez Ossorio, R; Gomez Herrera, F; Utrilla, R M; Hidalgo, A; Gamboa, J M

    1961-07-01

    The reactions were conducted in ethyl alcohol-dioxan, in the presence of EtONa, as catalyst. Rates were followed by a radioactive tracer method when R=H and by spectroscopic method when R= alkyl as described in previous papers. The results suggest that polar effects alone cannot account for the relative Arrhenius parameters obtained. (Author) 3 refs.

  6. Patient safety in a physics service medical. Checklist of key parameters to be revised before the dossier of the patient out of service; Seguridad del paciente en un servicio de fisica medica. Checklist de parametros clave a ser revisados antes de que el dossier del paciente salga del servicio

    Energy Technology Data Exchange (ETDEWEB)

    Font Gomez, J. A.; Gandia Martinez, A.; Jimenez Albericio, F. J.; Andres Redondo, M. M.; Mengual Gil, M. A.

    2013-07-01

    In aviation, operating rooms, etc. long checklists used parameters considered important / vital for review prior to the completion of work in the interest of safety. This ensures that any parameters key will be ignored by the computer so that it could cause future problems. (Author)

  7. Study of important parameters on the irradiation of {sup 124}Xe, to improve the production of {sup 123}I with high purity using the Cyclone-30 cyclotron at IPEN-CNEN/SP; Estudo de parametros relevantes na irradiacao de {sup 124}Xe, visando a otimizacao na obtencao de {sup 123}I ultra puro no ciclotron Cyclone-30 do IPEN-CNEN/SP

    Energy Technology Data Exchange (ETDEWEB)

    Sumiya, Luiz Carlos do Amaral

    2006-07-01

    The development of diagnosis equipment and therapy procedures in nuclear medicine depends on the availability of commercial radioisotopes. IPEN is the most important institution that provides radioisotopes for national market. In order to achieve this function, IPEN had invested in the acquisition of a 30 MeV Cyclone-30 cyclotron to produce mainly {sup 18}F, {sup 67}Ga, {sup 201}Tl and {sup 123}I. The {sup 123}I production is the aim of the present work. With the {sup 123}I routine production data obtained by proton irradiation of Xe targets with an enrichment greater than 99.8%, it was possible to identify the important parameters that have direct influence on the production yield of high purity degree {sup 123}I. Even though the methodology for the commercial production of {sup 123}I, there are an scarcity of operational parameters data for this task. In this work the evaluated parameters were: {sup 124}Xe pressure, proton beam quality, irradiation time, operational temperature of the irradiation system under irradiation, waiting time to obtain {sup 123}I, temperature of washing solution and the impact of the internal Ni coating in the target. With the obtained results it was possible to modify the operational conditions for routine production and increasing the efficiency in about 30%. (author)

  8. Preparation and properties of Li2O-BaO-Al2O3 -SiO2 glass-ceramic materials

    Directory of Open Access Journals (Sweden)

    Gamal A. Khater

    2014-12-01

    Full Text Available The crystallization of some glasses, based on celsian-spodumene glass-ceramics, was investigated by different techniques including differential thermal analysis, optical microscope, X-ray diffraction, indentation, microhardness, bending strengths, water absorption and density measurement. The batches were melted and then cast into glasses, which were subjected to heat treatment to induce controlled crystallization. The resulting crystalline materials were mainly composed of β-eucryptite solid solution, β-spodumene solid solution, hexacelsian and monoclinic celsian, exhibiting fine grains and uniform texture. It has been found that an increasing content of celsian phase in the glasses results in increased bulk crystallization. The obtained glass-ceramic materials are characterized by high values of hardness ranging between 953 and 1013 kg/mm2, zero water absorption and bending strengths values ranging between 88 and 126 MPa, which makes them suitable for many applications under aggressive mechanical conditions.

  9. X-ray fluorescence analysis of Fe, Mn, Cr and V in natural silicate crystals

    International Nuclear Information System (INIS)

    Dias, O.L.; Albuquerque, A.R.P.L.; Isotani, S.

    1983-04-01

    Concentrations of Fe, Mn, Cr and V were determined in samples of beryl, topaz, tourmaline and spodumene by measuring the first order K sub(α) fluorescence lines. The intensity of these lines were calibrated by using beryl as the standard matrix. The matrices were prepared in the form of pressed pellets with 4:1 mixture of beryl and boric acid, where transition metal oxides were added. (Author) [pt

  10. X-ray fluorescence analysis of Fe, Mn, Cr and V in natural silicate crystals

    International Nuclear Information System (INIS)

    Dias, O.L.; Albuquerque, A.R.P.L.; Isotani, S.

    1983-01-01

    Concentrations of Fe, Mn, Cr and V were determined in samples of beryl, topaze, tourmaline and spodumene by measuring the first order Kα fluorescence lines. The intensity of these lines were calibrated by using beryl as the standard matrix. The matrices were prepared in the form of pressed pellets with 4:1 mixture of beryl and boric acid, where transition metal oxides were added. (Author) [pt

  11. Influence of feldspar containing lithium in the sintering of triaxial ceramics

    International Nuclear Information System (INIS)

    Oliveira, Camila Felippe de; Strecker, Kurt

    2011-01-01

    In this work, the properties of a ceramic material based on a triaxial mass composed of clay, quartz and 15 to 30% feldspar, albite or spodumene, has been investigated. Specimen were prepared by uniaxial pressing under 28.5MPa and sintering at temperatures of 1000, 1100 and 1200 deg C, for 1h. The samples were characterized by their linear shrinkage, apparent porosity, apparent density and flexural strength, as well as analysis of the microstructure. The best results were obtained for samples prepared with 30% spodumene and sintered at 1200 deg C, with a shrinkage of 6.4%, density of 2.01g/cm 3 , porosity of 14.3% and flexural strength of 13.4MPa, while samples prepared with albite exhibited shrinkage of 5.8%, density of 1.9g/cm 3 , porosity of 18.9% and strength of 9.8MPa. Therefore, by the substitution of albite by spodumene in the ceramic triaxial mass, lower sintering temperatures may be employed, thus reducing production costs by the lesser energy consumption. (author)(

  12. Crystallization behavior of (1 - x)Li2O.xNa2O.Al2O3.4SiO2 glasses

    International Nuclear Information System (INIS)

    Wang, Moo-Chin; Cheng, Chih-Wei; Chang, Kuo-Ming; Hsi, Chi-Shiung

    2010-01-01

    The crystallization behavior of the (1 - x)Li 2 O.xNa 2 O.Al 2 O 3 .4SiO 2 glasses has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED) and energy dispersive spectroscopy (EDS). The crystalline phase was composed of β-spodumene. The isothermal crystallization kinetics of β-spodumene from the (1 - x)Li 2 O.xNa 2 O.Al 2 O 3 .4SiO 2 glasses has also been studied by a quantitative X-ray diffraction method. The activation energy of β-spodumene formation decreases from 359.2 to 317.8 kJ/mol when the Na 2 O content increases from 0 to 0.4 mol and it increases from 317.8 to 376.9 kJ/mol when the Na 2 O content increases from 0.4 to 0.6 mol. The surface nucleation and plate-like growth were dominant in the crystallization of the (1 - x)Li 2 O.xNa 2 O.Al 2 O 3 .4SiO 2 glasses.

  13. Crystallization behavior of (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Moo-Chin [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Cheng, Chih-Wei; Chang, Kuo-Ming [Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Road, Kaohsiung 80782, Taiwan (China); Hsi, Chi-Shiung, E-mail: chsi@nuu.edu.t [Department of Materials Science and Engineering, National United University, 1 Lien-Da, Kung-Ching Li, Miao-Li 36003, Taiwan (China)

    2010-07-02

    The crystallization behavior of the (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED) and energy dispersive spectroscopy (EDS). The crystalline phase was composed of {beta}-spodumene. The isothermal crystallization kinetics of {beta}-spodumene from the (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses has also been studied by a quantitative X-ray diffraction method. The activation energy of {beta}-spodumene formation decreases from 359.2 to 317.8 kJ/mol when the Na{sub 2}O content increases from 0 to 0.4 mol and it increases from 317.8 to 376.9 kJ/mol when the Na{sub 2}O content increases from 0.4 to 0.6 mol. The surface nucleation and plate-like growth were dominant in the crystallization of the (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses.

  14. Studies oriented to optimize the image quality of the small animal PET: Clear PET, modifying some of the parameters of the reconstruction algorithm IMF-OSEM 3D on the data acquisition simulated with GAMOS; Estudios para la optimizaciOn de la calidad de imagen en el escaner ClearPET, modifi cando parametros del algoritmo IMF-OSEM 3D sobre adquisiciones simuladas con GAMOS

    Energy Technology Data Exchange (ETDEWEB)

    Canadas, M.; Mendoza, J.; Embid, M.

    2007-09-27

    This report presents studies oriented to optimize the image quality of the small animal PET: Clear- PET. Certain figures of merit (FOM) were used to assess a quantitative value of the contrast and delectability of lesions. The optimization was carried out modifying some of the parameters in the reconstruction software of the scanner, imaging a mini-Derenzo phantom and a cylinder phantom with background activity and two hot spheres. Specifically, it was evaluated the incidence of the inter-update Metz filter (IMF) inside the iterative reconstruction algorithm 3D OSEM. The data acquisition was simulated using the GAMOS framework (Monte Carlo simulation). Integrating GAMOS output with the reconstruction software of the scanner was an additional novelty of this work, to achieve this, data sets were written with the list-mode format (LMF) of ClearPET. In order to verify the optimum values obtained, we foresee to make real acquisitions in the ClearPET of CIEMAT. (Author) 17 refs.

  15. Investigation of hyperfine parameters of semiconductor oxides SnO{sub 2} and TiO{sub 2} pure and doped with 3d transition methods using spectroscopy of perturbed gamma-gamma angular correlation; Investigacao de parametros hiperfinos dos oxidos semicondutores SnO{sub 2} and TiO{sub 2} puros e dopados com metais de transicao 3d pela espectroscopia de correlacao angular gama-gama perturbada

    Energy Technology Data Exchange (ETDEWEB)

    Schell, Juliana

    2015-09-01

    This study aimed the use of nuclear technique Perturbed γ-γ Angular Correlation Spectroscopy (PAC) to measure the hyperfine interactions in thin films and powder samples of SnO{sub 2} and TiO{sub 2} pure and doped with transition metals to obtain a systematic investigation of defects and magnetism from an atomic point of view with the main motivation the application in spintronics. The work also focused on the preparation and characterization of samples by conventional techniques such as X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and magnetization measurements. Pure samples of the films were measured by the systematic variation of thermal treatment and applied magnetic field. These measurements were performed in HISKP at the University of Bonn (Rheinische Friedrich-Wilhelms-Universität Bonn) using {sup 111}In({sup 111}Cd) or {sup 181}Hf ({sup 181}Ta); at IPEN, in turn, these measurements were performed after the diffusion of the same probe nuclei. Another part of PAC measurements were carried out using {sup 111}mCd({sup 111}Cd) and {sup 117}Cd ({sup 117}In) in Isotope Mass Separator On-Line (ISOLDE) at Centre Européen Recherche Nucléaire (CERN). The measurements were performed from 8 K to 1173 K. After comparing results from macroscopic techniques with those from PAC, it was concluded that there is a correlation between the defects, magnetism and the mobility of charge carriers in semiconductors studied here. A step forward in the search for semiconductors, whose magnetic ordering allows its use in electronics based on spin. Some results have been published, including results obtained at the University of Bonn for the sandwich doctorate period [1-7]. (author)

  16. Measurement of the $Z$ transverse momentum distribution in $\\bar{p} p \\to Z \\to e^+ e-$ events with the D0 detector

    Energy Technology Data Exchange (ETDEWEB)

    Magana-Mendoza, Leonel [Center for Research and Advanced Studies of the National Polytechnic Inst., Mexico City (Mexico)

    1997-10-01

    La medicion de la distribucion de momento longitudinal en eventos p$\\bar{p}$ → Z → e+e-constituye una prueba para las parametrizaciones de las funciones de distribucion partonica, al mismo tiempo que proporciona un nuevo conjunto de datos que pueden ser empleados como parametros de entrada en los ajustes globales encaminados a mejorar dichas parametrizaciones.

  17. A novel deformation mechanism for superplastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Muto, H.; Sakai, M. (Toyohashi Univ. of Technology (Japan). Dept. of Materials Science)

    1999-01-01

    Uniaxial compressive creep tests with strain value up to -0.1 for a [beta]-spodumene glass ceramic are conducted at 1060 C. From the observation of microstructural changes between before and after the creep deformations, it is shown that the grain-boundary sliding takes place via cooperative movement of groups of grains rather than individual grains under the large-scale-deformation. The deformation process and the surface technique used in this work are not only applicable to explain the deformation and flow of two-phase ceramics but also the superplastic deformation. (orig.) 12 refs.

  18. Influence of the mould on the size of A A 8090 alloy in the material melting bulk state

    International Nuclear Information System (INIS)

    Bolfarini, Claudemiro

    1996-01-01

    Wedge like samples were casted into investment moulds of alumina and spodumen. The later were additionally coated with lithium, barium, magnesium and calcium fluorides and chlorides based salts and other special materials. It was used the 2,6% Li-containing alloy AA8090. The grain size was measured as a function of the wedge thickness nd mould material. The results showed a strong dependence of the grain size to the mould materials for the same cast conditions: pouring temperature, mould temperature and chemical composition of the alloy. The AA8090 alloy had no addition of titanium-boron based grain refiner. (author)

  19. OH-point defects in quartz in B- and Li-bearing systems and their application to pegmatites

    Science.gov (United States)

    Baron, M. A.; Stalder, R.; Konzett, J.; Hauzenberger, C. A.

    2015-01-01

    OH incorporation in quartz in Al-, B- and Li-bearing systems (granitic systems containing tourmaline or spodumene) was studied experimentally in order to investigate the effect of pressure, temperature and chemical impurities on the generation of OH-defects. High-pressure experiments were carried out at pressures between 5 and 25 kbar and temperatures between 800 and 900 °C, and OH-contents in quartz were calculated from IR absorption spectra measured on oriented quartz crystals. IR absorption features were assigned to impurity substitutions, such as AlOH (3,420, 3,379 and 3,315 cm-1) and BOH (3,595 cm-1), LiOH (3,483 cm-1), and hydrogarnet substitution (4H)Si defects (3,583 cm-1). Results indicate a negative correlation of incorporated Al-specific OH-defect content versus pressure (630 ± 130 wt ppm H2O at 5 kbar to 102 ± 6 wt ppm H2O at 25 kbar), but no clear correlation of B-specific OH-defects with pressure. In runs initially containing spodumene, virtually OH-free quartzes were observed at pressures ≥10 kbar, where impurity cations compensate each other forming an anhydrous eucryptite-defect component. In contrast, at 5 kbar, both Li- ad Al-specific OH-defects are observed (corresponding to 470 ± 75 wt ppm H2O). Results from this study may therefore be used to monitor formation conditions of quartz in terms of pressure and trace metal saturation of the crystallizing petrological system. IR spectra obtained from natural quartz grains from a tourmaline-bearing pegmatite exhibit B- and Al-related OH-bands. The B-related OH-band is also exhibited in quartz from a tourmaline + spodumene-bearing pegmatite. Li- and Al-related OH-bands, however, are subordinate or not observed at all in the spodumene-bearing system, which suggests that OH-vibrations do not reflect absolute Li-contents in quartz due to efficient coupled substitution involving Al. Data from experimental runs and natural specimens indicate that the B-related OH-band can be used as a rough proxy for

  20. Some dispersive X-ray fluorescence applications in energies with radioisotopic excitation source; Algunas aplicaciones de la fluorescencia de rayos X dispersiva en energias con fuente de excitacion radioisotopica

    Energy Technology Data Exchange (ETDEWEB)

    Adelfang, P; Vazquez, C

    1991-12-31

    The aim of this work is based on the use of interelemental correction coefficients which are calculated through fundamental parameters. To this purpose, it is necessary to know about the physical constants for each element including the absorption coefficient values and fluorescence yield, the incidence radiation energy, geometric and instrumental parameters. Besides, a special application of the program for the determination of a Nd-La mixed crystal formula is included. (Author). [Espanol] La propuesta de este trabajo se basa en el empleo de coeficientes de correccion interelementales que son calculados a traves de los parametros fundamentales. Para ello se necesitan conocer las constantes fisicas para cada elemento que incluyen los valores de los coeficientes de absorcion y rendimiento de fluorescencia, la energia de la radiacion de incidencia y parametros instrumentales y geometricos. Se incluye ademas una aplicacion especial del programa para la determinacion de la formula de un cristal mixto de Nd y La. (Autor).

  1. Pedagogia etnomatemática: uma proposta para o ensino de matemática na educação básica

    Directory of Open Access Journals (Sweden)

    Francisco de Assis Bandeira

    2012-08-01

    Full Text Available As reflexoes apresentadas neste artigo sao parte de uma proposta de reorientacao curricular em educacao matematica que defende a utilizacao do conhecimento matematico vivenciado pelo aluno em sua comunidade como subsidio metodologico para o processo de ensino-aprendizagem da matematica escolar. Mas, a luz das concepcoes d.ambrosianas de Etnomatematica, principalmente, a educacional, que procura compreender a realidade sociocultural e chegar a acao pedagogica de maneira natural mediante um enfoque cognitivo com forte fundamentacao cultural. Para a concretizacao dessa proposta no campo educacional, busquei fundamentos legais, dentre os quais, os Parametros Curriculares Nacionais, que propoem ser apenas um documento de referencia para que as escolas organizem suas propostas curriculares. Nesse sentido, associei os blocos de conteudos dos Parametros Curriculares Nacionais do Ensino Fundamental da Matematica aos conhecimentos matematicos de uma comunidade de horticultores da Grande Natal/RN.

  2. El modelo de trabajo en equipo

    OpenAIRE

    Iñaki Rodríguez Cueto

    2008-01-01

    El modelo de trabajo en equipo constituye una herramienta basica en cualquier organizacion que quiera conseguir los objetivos propuestos y, ademas, lo quiera conseguir dentro de parametros de eficacia y calidad.En el entorno de la Comunidad Terapeutica cobra mayor importancia el dominio de saber trabajar en equipo debido a la necesidad de conjugar aspectos psico-terapeuticos, educativos, medicos e, incluso, administrativos a la hora de planificar el tratamiento a nivel grupal e individual.El ...

  3. Efectos de un programa de tratamiento multidisciplinar en obesos m??rbidos y obesos con comorbilidades candidatos a cirug??a bari??trica

    OpenAIRE

    Delgado Floody, Pedro; Caama??o Navarrete, Felipe; Jerez Mayorga, Daniel; Campos Jara, Christian Alex; Ram??rez Campillo, Rodrigo; Osorio Poblete, Aldo; Alarc??n Hormaz??bal, Manuel; Thuillier Lepeley, Nicole; Saldivia Mansilla, Claudia

    2015-01-01

    Introducci??n: La obesidad morbida es una enfermedad que debe ser tratada de forma integral (i.e., multi/ interdisciplinar). Para esta condicion la cirugia bariatrica es efectiva y segura en el tratamiento, sin embargo, a mayor peso preoperatorio podria aumentar la morbimortalidad. Objetivo: El objetivo del estudio es determinar los efectos de un programa de tratamiento interdisciplinar sobre parametros metabolicos, antropometricos y la condicion fisica en candidatos a cirugia bariatrica. Mat...

  4. The phase transformation and crystallization kinetics of (1 - x)Li{sub 2}O-xNa{sub 2}O-Al{sub 2}O{sub 3}-4SiO{sub 2} glasses

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Moo-Chin [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Li, Wang-Long [Institute of Nanotechnology and Microsystems Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Cheng, Chih-Wei [Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Road, Kaohsiung 80782, Taiwan (China); Chang, Kuo-Ming; Chen, Yong-Feng [Department of Electrical Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Hsi, Chi-Shiung, E-mail: chsi@nuu.edu.tw [Department of Materials Science and Engineering, National United University, 1 Lein-Da, Kung-Ching Li, Miaoli 36003, Taiwan (China)

    2010-09-01

    The phase transformation and crystallization kinetics of (1 - x)Li{sub 2}O-xNa{sub 2}O-Al{sub 2}O{sub 3}-4SiO{sub 2} glasses have been studied by using differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron diffraction (ED) analysis. The crystallization temperature at the exothermic peak increases from 1171 to 1212 K when the Na{sub 2}O content increases from 0 to 0.6 mol. The crystalline phase is composed of spodumene crystallization when the Na{sub 2}O content increases from 0 to 0.6 mol. The activation energy of spodumene crystallization decreases from 444.0 {+-} 22.2 to 284.0 {+-} 10.8 kJ mol{sup -1} when the Na{sub 2}O content increases from 0 to 0.4 mol. Moreover, the activation energy increases from 284.0 {+-} 10.8 to 446.0 {+-} 23.2 kJ mol{sup -1} when the Na{sub 2}O content increases from 0.4 to 0.6 mol. The crystallization parameters m and n approach 2, indicating that the surface nucleation and two-dimensional growth are dominant in (1 - x)Li{sub 2}O-xNa{sub 2}O-Al{sub 2}O{sub 3}-4SiO{sub 2} glasses.

  5. The phase transformation and crystallization kinetics of (1 - x)Li2O-xNa2O-Al2O3-4SiO2 glasses

    International Nuclear Information System (INIS)

    Wang, Moo-Chin; Li, Wang-Long; Cheng, Chih-Wei; Chang, Kuo-Ming; Chen, Yong-Feng; Hsi, Chi-Shiung

    2010-01-01

    The phase transformation and crystallization kinetics of (1 - x)Li 2 O-xNa 2 O-Al 2 O 3 -4SiO 2 glasses have been studied by using differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron diffraction (ED) analysis. The crystallization temperature at the exothermic peak increases from 1171 to 1212 K when the Na 2 O content increases from 0 to 0.6 mol. The crystalline phase is composed of spodumene crystallization when the Na 2 O content increases from 0 to 0.6 mol. The activation energy of spodumene crystallization decreases from 444.0 ± 22.2 to 284.0 ± 10.8 kJ mol -1 when the Na 2 O content increases from 0 to 0.4 mol. Moreover, the activation energy increases from 284.0 ± 10.8 to 446.0 ± 23.2 kJ mol -1 when the Na 2 O content increases from 0.4 to 0.6 mol. The crystallization parameters m and n approach 2, indicating that the surface nucleation and two-dimensional growth are dominant in (1 - x)Li 2 O-xNa 2 O-Al 2 O 3 -4SiO 2 glasses.

  6. Penetration of the renewable sources of energy in Mexico: group of approach to determine the exogenous parameters of the LEAP simulation model (Annexe 10 in 'A vision of year 2030 on the use of the renewable energies in Mexico'); Penetracion de las fuentes renovables de energia en Mexico: grupo de enfoque para determinar los parametros exogenos del modelo de simulacion LEAP (Anexo 10 en 'Una vision al 2030 de la utilizacion de las energias renovables en Mexico')

    Energy Technology Data Exchange (ETDEWEB)

    Pernudi, Montserrat; Alonso C, Antonio [Analitica Consultores S.A. de C.V., Mexico D.F. (Mexico)

    2005-08-15

    The LEAP simulation model requires the values of some exogenous variables: At international level, the population increase, the economic growth and the international oil prices; at domestic level, the population increase, the economic growth, the energy intensity, the elasticity of demand of energy-price, and the elasticity of energy demand-gross national product. The use of the LEAP model for the estimation of the penetration of the renewable energies in Mexico comprises of the requirements established in the study. To estimate the future long term values of variables as the exogenous ones required by this model by means of expert opinion can be, given the nature of same, equally or more complicated and speculative than to directly consider the future rates of penetration of the renewable energies. In order to reflect on the future values of these variables a group of approach with experts was integrated. [Spanish] El modelo de simulacion LEAP requiere los valores de algunas variables exogenas: A nivel internacional, el crecimiento demografico, el crecimiento economico y los precios internacionales del petroleo; a nivel nacional, el crecimiento demografico, el crecimiento economico, la intensidad energetica, la elasticidad de demanda de energia-precio, y la elasticidad de demanda de energia-producto interno bruto. El uso del modelo LEAP para la estimacion de la penetracion de las energias renovables en Mexico forma parte de los requerimientos establecidos en el estudio. Estimar los futuros valores a largo plazo de variables como las exogenas requeridas por dicho modelo mediante opinion experta puede resultar, dada la naturaleza de las mismas, tan o mas complicado y especulativo que estimar las futuras tasas de penetracion de las energias renovables directamente. Para reflexionar sobre los futuros valores de dichas variables se integro un grupo de enfoque con expertos.

  7. Análise de parâmetros de força e resistência dos músculos eretores da espinha lombar durante a realização de exercício isométrico em diferentes níveis de esforço Análisis de los parametros de fuerza y resistencia de los músculos erectores de la columna lumbar durante la realizacion de exercício isométrico en diferentes níveles de esfuerzo Analysis of strength and resistance parameters of the lumbar spinae erector muscles during isometric exercise at different effort levels

    Directory of Open Access Journals (Sweden)

    Mauro Gonçalves

    2005-04-01

    Full Text Available A dor lombar tem demonstrado ser um achado comum em atletas e, particularmente, a sobrecarga na coluna lombar em conseqüência de um comprometimento da força ou resistência isométrica de músculos desse segmento, como resultado da fadiga muscular, tem sido considerada como importante fator etiológico para o seu desenvolvimento. Nesse sentido, destacam-se testes utilizados para a avaliação e treinamento dos músculos eretores da espinha lombares. No presente estudo, a análise de parâmetros de força e resistência isométrica foi utilizada com o objetivo de avaliar as respostas desses músculos durante contrações isométricas voluntárias máximas (CIVM e submáximas em duas situações: com fadiga e sem fadiga, induzida por exercício isométrico realizado até a exaustão. Nove voluntários do gênero masculino e saudáveis realizaram CIVM antes e após exercícios de extensão da coluna vertebral sustentando 5%, 10%, 15% e 20% da CIVM. Em cada uma dessas situações foi registrado o sinal eletromiográfico (EMG dos músculos iliocostal e multífido, assim como o nível de força gerado nas CIVM. A fadiga muscular foi identificada pela verificação do declínio dos valores de CIVM e freqüência mediana (FM do sinal EMG obtidos após os exercícios isométricos. Os resultados demonstraram que, enquanto a força não foi capaz de evidenciar a fadiga muscular, a FM demonstrou de forma estatisticamente significante a fadiga dos músculos iliocostal e multífido, sendo observado neste último maior nível de fadiga muscular. De forma interessante, cargas entre 5% e 20% da CIVM induziram um mesmo nível de fadiga muscular. Assim, embora a força gerada durante a extensão da coluna vertebral após a exaustão induzida por exercício isométrico permaneça inalterada, provavelmente pela ação de músculos acessórios desse movimento, a sobrecarga sobre a coluna vertebral desenvolve-se como conseqüência do comprometimento da sua estabilidade decorrente da fadiga muscular identificada após exercício isométrico.El dolor lumbar es un hallazgo común en los atletas, y particularmente, la sobrecarga de la columna lumbar es consecuencia de un comportamiento de la fuerza o resistencia isométrica de los músculos de este segmento como resultado de la fatiga muscular ha sido considerada como un importante factor etiológico para su desarrollo. En este sentido, se destacan tests utilizados para la evaluación de los músculos erectores de la columna lumbar. En el presente estudio, el análisis de parámetros e fuerza y resistencia isométrica fué utilizada como objetivo de evaluar las respuestas de estos músculos durante las contracciones isométricas voluntarias máximas (CIVM y sub-máximas en dos situaciones: con fatiga y sin fatiga inducida por el ejercicio isométrico realizado a extenuación. Nueve voluntarios de sexo masculino y saludables realizaron una CIVM antes y después de ejercicios de extensión de la columna vertebral sustentando 5%, 10%, 15% e 20% de la CIVM. En cada una de esas situaciones fué registrado la señal eletromiográfica (EMG de los músculos iliocostal y multífido, así como el nivel de fuerza generado en las CIVM. La fatiga muscular fué identificada por la verificación del de la caída de los valores de CIVM y frecuencia mediana (FM de la señal EMG obtenidos después de los ejercicios isométricos. Los resultados demostraron que en cuanto la fuerza no fué capaz de evidenciar la fatiga muscular, la FM demostró de forma estadísticamente significante la fatiga de los músculos iliocostal e multífido, siendo observado en este último un mayor nivel de fatiga muscular. De forma interesante, las cargas entre 5% y 20% de la CIVM inducirán a un mismo nivel de fatiga muscular. Así, ahora la fuerza generada durante la extensión de la columna vertebral después de la extenuación inducida por el ejercicio isométrico permanezca inalterada, probablemente por la acción de los músculos accesorios de este movimiento, la sobrecarga sobre la columna vertebral se desarrolla como consecuencia del compromiso de la estabilidad de la columna vertebral consecuente de la fatiga muscular identificada después del ejercicio isométrico.The low-back pain has demonstrated to be a common finding among athletes and particularly the overload in the lumbar column resulting from a strength or isometric resistance involvement of muscles of this segment as result of the muscular fatigue has been considered as important etiological factor for its development. In this context, tests used for the training evaluation of the lumbar spinae erector muscles are emphasized. In the present study, the analysis of the strength and isometric resistance parameters was used with the objective of evaluating responses of these muscles during maximal and sub-maximal voluntary isometric contractions (MVIC in two situations: with fatigue and without fatigue induced by isometric exercise performed until exhaustion. Nine male healthy volunteers performed MVIC before and after vertebral column extension exercises supporting 5%, 10%, 15% and 20% of the MVIC. In each one of these situations, the electromyographic signal (EMG of the iliocostalis and multifidus muscles as well as the strength level generated in the MVIC were recorded. Muscular fatigue was identified through the MVIC values decrease verification and median frequency (MF of the EMG signals obtained after isometric exercise. The results demonstrated that while the strength was able to evidence muscular fatigue, the MF demonstrated in a statistically significant way the iliocostalis and multifidus muscles fatigue, and the multifidus muscles presented a higher muscular fatigue level. Interestingly, loads between 5% and 20% of the MVIC induced the same level of muscular fatigue. Thus, although the strength generated during vertebral column extension after isometric exercise-induced exhaustion remains unchanged, probably due to the action of accessory muscles, the overload on the vertebral column is developed as result of the vertebral column stability involvement resulting from the muscular fatigue identified after isometric exercise.

  8. Irreversibility analysis of non isothermal flat plate solar collectors for air heating with a dimensionless model; Analisis de las irreversibilidades en colectores solares de placas planas no isotermicos para calentamiento de aire utilizando un modelo adimensional

    Energy Technology Data Exchange (ETDEWEB)

    Bracamonte-Baran, Johane Hans; Baritto-Loreto, Miguel Leonardo [Universidad Central de Venezuela (Venezuela)]. E-mails: johanehb@gmail.com; johane.bracamonte@ucv.ve; miguel.baritto@ucv.ve

    2013-04-15

    The dimensionless model developed and validated by Baritto and Bracamonte (2012) for the thermal behavior of flat plate solar collector without glass cover is improved by adding the entropy balance equation in a dimensionless form. The model is solved for a wide range of aspect ratios and mass flow numbers. A parametric study is developed and the distribution of internal irreversibilities along the collector is analyzed. The influence of the design parameters on the entropy generation by fluid friction and heat transfer is analyzed and it is found that for certain combinations of these parameters optimal thermodynamic operation can be achieved. [Spanish] En el presente trabajo, el modelo adimensional desarrollado y validado por Baritto y Bracamonte (2012) para describir el comportamiento termico de colectores solares de placas planas sin cubierta transparente, se complementa con la ecuacion adimensional de balance de entropia para un elemento diferencial de colector solar. El modelo se resuelve para un amplio rango de valores de relaciones de aspecto y numero de flujo de masa. A partir de los resultados del modelo se desarrolla un analisis detallado de la influencia de estos parametros sobre la distribucion de irreversibilidades internas a lo largo del colector. Adicionalmente se estudia la influencia de estos parametros sobre los numeros de generacion de entropia por friccion viscosa, por transferencia de calor y total. Se encuentra que existen combinaciones de los parametros antes mencionados, para los cuales, la operacion del colector es termodinamicamente optima para numeros de flujo de masa elevados.

  9. Influence of the spatial discretization degree on the hydrological response of a flatland watershed through distributed mathematical modeling; Influencia del grado de discretizacion espacial en la respuesta hidrologica de una cuenca de llanura mediante modelacion matematica distribuida

    Energy Technology Data Exchange (ETDEWEB)

    Stenta, Herman Roberto; Riccardi, Gerardo A; Basile, Pedro A [Universidad Nacional de Rosario (Mexico)

    2008-07-15

    Distributed hydrological models are suitable for the determination of time and space variability of hydrological responses within a given watershed. In a watershed, the model can be implemented with different levels of space resolution, mainly as a function of data availability, objectives of the numerical study, and requirements of the system to be modeled. In this paper, the effects on landscape representation due to different cell sizes are analyzed and scaling of parameters in a lower spatial resolution level is proposed in order to obtain similarity in hydrological responses between different degrees of discretization. The comparison was made in terms of maximum discharge, maximum flow velocity, and maximum water depth by simulating a number of observed and hypothetical hydrological events. The concept of total equilibrium state of the watershed was used. Under these circumstances, the roughness coefficients associated to overland and stream flow and the storage function of each discretization element were adjusted separately for the lower spatial resolution level. The results show that the similarity in hydrological responses, in terms of maximum water depth, obtained by adjusting the storage function of the cells, is better than that corresponding to the adjustment of roughness coefficients. [Spanish] Los modelos matematicos de parametros distribuidos resultan particularmente apropiados para determinar la variabilidad espacial y temporal de las respuestas hidrologicas dentro de un determinado sistema hidrico. En una cuenca es posible realizar la constitucion de un modelo con diferentes niveles de detalle en funcion principalmente de la disponibilidad de informacion de entrada necesaria, de los objetivos de estudio y de los requerimientos de modelado del sistema. En el presente trabajo se analizan los efectos producidos en la representacion del relieve debido a los diferentes tamanos de celda en que se ha discretizado una cuenca de llanura y se propone el

  10. Parametric sensitivity of two axis models for turbo-generators; Sensibilidad parametrica de modelos de dos ejes para turbogeneradores

    Energy Technology Data Exchange (ETDEWEB)

    Morales Castorena, Armando

    2003-06-15

    also believed that some insights into the electromagnetic phenomena of the machine can be achieved from these studies, because of the mathematical representation that the fitness functions do of the physics of the machine. A set of five equivalent circuits on the d axis and four on the q axis were studied. The difference between circuits is the number of damper windings that are modeled. These windings represent the damper effects of the rotor during transient states of the machine. When modeling rotor damping effects, the more number of damper windings is included the better is the fitness of the circuit frequency response to the one of the machine, also leading to better results during dynamic simulations. [Spanish] En esta tesis se presentan los resultados de un estudio de sensibilidad parametrica realizado a circuitos equivalentes de dos ejes de turbogeneradores. Los circuitos estan formados por elementos inductivos y resistivos, cuya conectividad representa el acoplamiento magnetico y electrico al interior de la maquina, y las perdidas energeticas en la misma. Se tienen dos circuitos equivalentes, uno para el eje directo (d) y otro para el eje de cuadratura (q), debido a que el turbogenerador es modelado en el marco de referencia del rotor con la transformacion de Park. Las magnitudes de los parametros de los circuitos han sido determinados previamente a partir de pruebas de respuesta a la frecuencia en reposo. La respuesta a la frecuencia fue determinada haciendo uso de un modelo de elementos finitos de un turbogenerador. La tecnica de determinacion de la magnitud de los parametros consiste en un proceso de optimizacion basado en un algoritmo hibrido (combinacion de algoritmo genetico y algoritmo deterministico), cuyo indice de optimizacion esta formado por el cuadrado de las diferencias de las magnitudes y los angulos de fase entre las respuestas a la frecuencia del circuito y de la maquina. Se tiene entonces que las magnitudes de los parametros de los circuitos

  11. Pt{sub X}Ru{sub Y}Ir{sub Z} as a bifunctional electrocatalyst for oxygen reduction reaction in a PEM fuel cell; Pt{sub X}Ru{sub Y}Ir{sub Z} como electrocatalizador bifuncional para la reaccion redox del oxigeno en una celda tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Morales, L.; Fernandez, A.M. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Temixco, Morelos (Mexico)]. E-mail: limos@cie.unam.mx; Cano, U. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2009-09-15

    This work presents the synthesis and characterization of the ternary material Pt{sub X}Ru{sub Y}Ir{sub Z}, obtained by chemical reduction with NaBH{sub 4}. Two different atomic compositions were developed (sample A and B) in order to observe the kinetic effect, as suggested by the combinatorial libraries. The main objective of this synthesis is to study the oxygen reduction reaction (ORR and OER) and its potential use in the construction of a bifunctional catalyst. In addition, each of the metals are synthesized separately using the same technique in order to make the corresponding comparison. The compounds obtained were characterized by sweep electron microscopy, x-ray diffraction and composition using fluorescence and energy-dispersive x-ray spectroscopy. The results showed a displacement of the x-ray diffraction peaks for Ir and Pt in sample A, and displacement in sample B for Ru and Ir peaks. These changes suggest the possible formation of a solid solution substitution. Separate cyclic and linear voltamperometry studies were performed for the oxygen reduction and release reactions. The electrochemical analysis showed improved kinetic behavior when combining the three metals according to the composition of sample B. [Spanish] En este trabajo se presenta la sintesis y caracterizacion del material ternario Pt{sub X}Ru{sub Y}Ir{sub Z}, elaborado por la tecnica de Reduccion Quimica utilizando al NaBH{sub 4}. Se elaboraron dos composiciones atomicas diferentes (Muestra A y B) con el fin de observar el efecto cinetico, como lo sugieren las librerias combinatorias. El objetivo principal de esta sintesis es para el estudio de la Reaccion Redox del Oxigeno (RRO y REO) y su potencial uso para la construccion de un catalizador bifuncional. Asi mismo, se realiza la sintesis de cada uno de los metales por separado empleando la misma tecnica, con el proposito de realizar la comparacion correspondiente. Los compuestos obtenidos se caracterizaron por Microscopia Electronica de

  12. Superplastic ceramics and intermetallics and their potential applications

    International Nuclear Information System (INIS)

    Wadsworth, J.; Nieh, T.G.

    1994-11-01

    Recent advances in the basic understanding of superplasticity and superplastic forming of ceramics and intermetallics are reviewed. Fine-grained superplastic ceramics, including yttria-stabilized tetragonal zirconia polycrystal, Y- or MgO-doped Al 2 O 3 Hydroxyapatite, β-spodumene glass ceramics, Al 2 0 3 -YTZP two-phase composites, SiC-Si 3 N 4 and Fe-Fe 3 C composites, are discussed. Superplasticity in the nickel-base (e.g., Ni 3 Al and Ni 3 Si) and titanium-base intermetallics (TiAl and T1 3 Al), is described. Deformation mechanisms as well as microstructural requirements and effects such as grain size, grain growth, and grain-boundary phases, on the superplastic deformation behavior am addressed. Factors that control the superplastic tensile elongation of ceramics are discussed. Superplastic forming, and particularly biaxial gas-pressure forming, of several ceramics and intermetallics are presented with comments on the likelihood of commercial application

  13. Dosimetric and thermoluminescent characteristics of sintered samples based on Li{sub 2}OAl{sub 2}O{sub 3}nSiO{sub 2} systems

    Energy Technology Data Exchange (ETDEWEB)

    Cogollo P, R.; Salcedo Q, J. [Universidad de Cordoba, Materials and Applied Physics Group, Carrera 6 No. 76-103, Monteria, Cordoba (Colombia); Gutierrez F, O., E-mail: rafaelcogollo@correo.unicordoba.edu.co [Metropolitan Technological Institute, Alquimia Group, Calle 54 No. 30-01, Medellin (Colombia)

    2013-10-01

    This work describes the thermoluminescent (Tl) characteristics of lithium aluminosilicates, Li{sub 2}OAl{sub 2}O{sub 3}nSiO{sub 2}, for its possible use as Tl dosimeter for low doses. The sinterized tablets of Li{sub 2}OAl{sub 2}O{sub 3}nSiO{sub 2} were characterized by means of X-ray diffraction (XRD), and irradiated at different doses using a Theratron 780 C-{sup 60}Co unit in air at room temperature. The Rasheedy's technique was used for the kinetic trap parameters determination. The XRD results show a mixture of two phases of 64% {beta}-spodumene and 36% {beta}-eucryptite in the sinterized tablets. Tl analysis indicates that in these systems, recombination processes prevail, and that these systems can be used successfully as Tl dosimeters for therapeutic dose ranges. (Author)

  14. Geologic and radiometric prospect of the mine ''El Muerto'' Oaxaca, Mex

    International Nuclear Information System (INIS)

    Manjarrez C, E.

    1981-01-01

    The studies realized in the mine demonstrated that the uranium mineral inclosure obtained in the pegmatites exists in very little concentrations and does not constitute useful deposits. Therefore, there are found rare earths minerals like monazite and euxenite so the mine may be proficient in the extraction of other type of minerals like spodumene, beryl, etc. Because of the scarce knowledges that we have about the pegmatites referring to the radiactive minerals study, it is stated the necessity of making programs perfectly coordinated and projected in the application of the metallurgic investigation that permits the increase in results of useful value, without to lose sight that the principal objective is to have a real economic, industrial and scientific view of the radiactive minerals localized in the pegmatites, considering the refractory character of the same, and the mineral little volume that in general they contain. (author)

  15. Visualisation of the high-current e-beams on solid surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Solomonov, V I; Osipov, V V; Mikhajlov, S G; Lipchak, A I [Russian Academy of Sciences, Ural Division, Ekaterinburg (Russian Federation). Institute of Electrophysics

    1997-12-31

    Natural minerals such as spodumen, calcite, and Mn-doped apatite crystals may serve as suitable low-cost materials for visualization of high-current electron beams. High-intensity luminescence lasting several tens of minutes has been observed when irradiating natural specimen by electron beams with the current density of 10-1000 A/sq.cm, with energy of 100-300 keV, and pulse duration of 2-50 ns. The luminescent images of the beam cross-section provide information on the beam density profiles, while the images taken in the plane parallel to the beam axis make it possible to estimate the beam penetration depth and, therefore, the beam energy. The method is illustrated by examples of luminescent images taken from the experiment. (J.U.).

  16. Cobalt-Free Permanent Magnet Alloys.

    Science.gov (United States)

    1984-10-01

    ThC Ferrites (Zn, Mn. Cu, Fe)O A12O. Al TiC Kaolin Al203.Si02-Fe2O3 Fe2O3 Li B4C Spodumene LiAI (SiOs) 2 ThO2 Ni UC Rhodonite NtnO. SiO2 MnOs Fe TaC...minutes. X-ray diffraction pattern indicated the presence of magnetic T phase. Hysteresis loop was measured on the heat treated powder dispersed in wax...fmgei * T phse Hysersi loo was mesue on the. heat - treated ,--". " powder dispersed in wax... The’ result wer as"- follows: • , " • "• . I TABLE 6

  17. Current instabilities under HF electron gas heating in semiconductors with negative differential conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Gurevich, Yu. G.; Logvinov, G. N. [Instituto Politecnico Nacional, Mexico, D.F. (Mexico); Laricheva, N. [Datmouth College, New Hampshire (United States); Mashkevich, O. L. [Kharkov University, Kharkov (Ukraine)

    2001-10-01

    A nonlinear temperature dependence of the kinetic coefficients of semiconductor plasma can result in the appearance of regions of negative differential conductivity (NDC) in both the high-frequency (HF) and static current-voltage characteristics (CVC). In the present paper the formation of the static NDC under simultaneous electron gas heating by HF and static electric field is studied. As is shown below, in this case the heating electromagnetic wave has a pronounced effect on the appearance of NDC caused by the overheating mechanisms and the type of the static CVC as a whole. [Spanish] Una dependencia no lineal de la temperatura de los coeficientes cineticos del plasma del semiconductor puede llevar a la aparicion de regiones con conductividad diferencial negativa (CDN) en las caracteristicas corriente voltaje (CCV) de alta frecuencia (AF) y estatica. En este articulo se estudia la formacion de la CDN estatica bajo la accion simultanea del calentamiento del gas de electrones por AF y el campo electrico estatico. Como se muestra mas adelante, en este caso la onda electromagnetica que calienta a los electrones ejerce un fuerte efecto en la aparicion de la CDN; que se obtiene por mecanismos de sobrecalentamiento, y en el tipo de CCV estatica.

  18. Rare Mineralogy in Alkaline Ultramafic Rocks, Western Kentucky Fluorspar District

    Science.gov (United States)

    Anderson, W.

    2017-12-01

    The alkaline ultramafic intrusive dike complex in the Western Kentucky Fluorspar District contains unusual mineralogy that was derived from mantle magma sources. Lamprophyre and peridotite petrologic types occur in the district where altered fractionated peridotites are enriched in Rare Earth Elements (REE) and some lamprophyre facies are depleted in incompatible elements. Unusual minerals in dikes, determined by petrography and X-ray diffraction, include schorlomite and andradite titanium garnets, astrophyllite, spodumene, niobium rutile, wüstite, fluoro-tetraferriphlogopite, villiaumite, molybdenite, and fluocerite, a REE-bearing fluoride fluorescent mineral. Mixing of MVT sphalerite ore fluids accompanies a mid-stage igneous alteration and intrusion event consistent with paragenetic studies. The presence of lithium in the spodumene and fluoro-tetraferriphlogopite suggests a lithium phase in the mineral fluids, and the presence of enriched REE in dikes and fluorite mineralization suggest a metasomatic event. Several of these rare minerals have never been described in the fluorspar district, and their occurrence suggests deep mantle metasomatism. Several REE-bearing fluoride minerals occur in the dikes and in other worldwide occurrences, they are usually associated with nepheline syenite and carbonatite differentiates. There is an early and late stage fluoride mineralization, which accompanied dike intrusion and was also analyzed for REE content. One fluorite group is enriched in LREE and another in MREE, which suggests a bimodal or periodic fluorite emplacement. Whole-rock elemental analysis was chondrite normalized and indicates that some of the dikes are slightly enriched in light REE and show a classic fractionation enrichment. Variations in major-element content; high titanium, niobium, and zirconium values; and high La/Yb, Zr/Y, Zr/Hf, and Nb/Ta ratios suggest metasomatized lithospheric-asthenospheric mantle-sourced intrusions. The high La/Yb ratios in some

  19. Building solar dryer of tropical woods; Construccion de un secador solar de maderas tropicales

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez R, J; Flores M, F. E; Cuevas D, O [Universidad de Quintana Roo, Chetumal, Quintana Roo (Mexico); Tolentino E, G [LABINTHAP-SEPI-ESIME-IPN, Mexico, D.F. (Mexico)

    2000-07-01

    In Quintana Roo, Mexico, several species of wood are used for handicrafts. The most commonly method used in the communities nearby Chetumal is natural drying, with the disadvantage of low quality in their products because the moisture contains in the wood. In this project studied the design of solar dryer for tropical woods in Quintana Roo. [Spanish] En este trabajo, se parte del analisis de las condiciones climatologicas existentes en el estado de Quintana Roo, Mexico, asi como de las necesidades de madera seca de una comunidad, como parametros basicos para el diseno y construccion de un secador solar de maderas tropicales.

  20. On the Logical Development of Statistical Models.

    Science.gov (United States)

    1983-12-01

    1978). "Modelos con parametros variables en el analisis de series temporales " Questiio, 4, 2, 75-87. [25] Seal, H. L. (1967). "The historical...example, a classical state-space representation of a simple time series model is: yt = it + ut Ut = *It-I + Ct (2.2) ut and et are independent normal...on its past values is displayed in the structural equation. This approach has been particularly useful in time series models. For example, model (2.2

  1. The influence of disinfectants on mutagenicity and on toxicity of urban waste water; Valutazione di trattamenti di disinfezione di acque reflue urbane mediante test di tossicita' e di mutagenesi

    Energy Technology Data Exchange (ETDEWEB)

    Monarca, S. [Brescia Univ., Brescia (IT). Dipt. di Medicina Sperimentale e Applicata] [and others

    1999-12-01

    The aim of the research was to study the influence of disinfectants alternative to chlorine, such as chlorine dioxide, ozone, peracetic acid and UV radiation, have on the formation of mutagenic and toxic compounds in waste water disinfection. Preliminary results are presented and discussed. [Italian] Scopo del lavoro e' stato lo studio dell'azione antimicrobica di diversi disinfettanti su acque reflue urbane dopo trattamento secondario, correlando tale parametro con l'attivita' tossica e genotossica prodotta dalla disinfezione. I risultati vengono presentati e discussi.

  2. Application of frequency converters in industry; Aplicacion de convertidores de frecuencia en la industria

    Energy Technology Data Exchange (ETDEWEB)

    Adame Gonzalez, A.; Aguilar Galvan, A. [Ingenieria Energetica Integral, S.A. de C.V. (Mexico)

    1997-12-31

    Some of the applications of the frequency converters will be analyzed, as well as the parameters to be considered for the feasibility of its application evaluation. It is also described how an energy evaluation is accomplished and finally a series of actions are enlisted conducting to the energy savings. [Espanol] Se presentaran algunas de las aplicaciones de los convertidores de frecuencia. Ademas se indicaran los parametros a registrar para evaluar la factibilidad de aplicacion de los mismos, se describe como ejecutar la evaluacion energetica y finalmente se listan una serie de acciones que conducen a lograr ahorros de energia.

  3. Evaluation of energy saving in large scale projects in domestic lighting; Evaluacion del ahorro de energia en proyectos de gran escala en alumbrado domestico

    Energy Technology Data Exchange (ETDEWEB)

    Valera Negrete, Adrian [Comision Federal de Electricidad, Mexico, D.F. (Mexico)

    2001-07-01

    The present work shows the methodology and the necessary parameters are indicated to evaluate the energy saving and the reduction of power demand obtained, by the large scale projects of substitution of incandescent lamps by compact, circular fluorescent and globe type lamps in the domestic sector. [Spanish] El presente trabajo muestra la metodologia y se indican los parametros necesarios para evaluar el ahorro de energia y reduccion de la demanda de potencia obtenidos, por los proyectos de gran escala de sustitucion de focos incandescentes por lamparas fluorescentes compactas, circulares y tipo globo en el sector domestico.

  4. Evaluation of energy saving in pilot projects of window type air conditioning equipment in the domestic sector; Evaluacion del ahorro de energia en proyectos pilotos en equipos de aire acondicionado tipo ventana en el sector domestico

    Energy Technology Data Exchange (ETDEWEB)

    Duran Ramirez, Ricardo [Comision Nacional para el Ahorro de Energia, Mexico, D.F. (Mexico)

    2001-07-01

    The present work shows the energy saving when replacing low efficiency window type air conditioning equipment, for higher efficiency equipment, as well as the necessary parameters to identify the results obtained by the pilot projects of substitution of conventional equipment for other more efficient in the domestic sector. [Spanish] El presente trabajo muestra los ahorros de energia al sustituir equipos de aire acondicionado tipo ventana de baja eficiencia, por equipos de mayor eficiencia, asi como los parametros necesarios para identificar los resultados obtenidos, por los proyectos pilotos de sustitucion de equipos convencionales por otros mas eficientes en el sector domestico.

  5. Application of frequency converters in industry; Aplicacion de convertidores de frecuencia en la industria

    Energy Technology Data Exchange (ETDEWEB)

    Adame Gonzalez, A; Aguilar Galvan, A [Ingenieria Energetica Integral, S.A. de C.V. (Mexico)

    1998-12-31

    Some of the applications of the frequency converters will be analyzed, as well as the parameters to be considered for the feasibility of its application evaluation. It is also described how an energy evaluation is accomplished and finally a series of actions are enlisted conducting to the energy savings. [Espanol] Se presentaran algunas de las aplicaciones de los convertidores de frecuencia. Ademas se indicaran los parametros a registrar para evaluar la factibilidad de aplicacion de los mismos, se describe como ejecutar la evaluacion energetica y finalmente se listan una serie de acciones que conducen a lograr ahorros de energia.

  6. Evaluación de complejos enzimáticos en alimentación de pollos de engorde

    OpenAIRE

    García Jiménez, Mario

    2011-01-01

    El objetivo de esta tesis doctoral ha sido evaluar la adición de diversos complejos enzimáticos a dietas basadas en cereales que contenían diferentes cantidades de polisacáridos no amiláceos (PNA), sobre la productividad y parametros digestivos de pollos de engorde. Asimismo se ha estudiado la variación de la respuesta a la suplementación enzimática(SE) en función de otros factores tales como el periodo de ayuno posterior al nacimiento, el procesamiento termico del cereal, el tipo de cereal u...

  7. Thermodynamic performance of gas turbine; Comportamiento termodinamico de las turbinas de gas

    Energy Technology Data Exchange (ETDEWEB)

    Lugo Leyte, Raul [Universidad Autonoma Metropolitana-Iztapalapa, Mexico D.F. (Mexico); Velazquez Toledo, Miguel; Hernandez Fernandez, Angel [Escuela Superior de Ingenieria Mecananica y Electrica, Academia Mecanica, Instituto Politecnico Nacional, Mexico D.F. (Mexico); Torres Aldaco, Alejandro [Universidad Autonoma Metropolitana-Iztapalapa, Mexico D.F. (Mexico)

    2003-01-15

    This work presents a computer code developed to simulate thermodynamic performance of a gas turbine cycle. The predicted performance is determined by measurements, in terms of various thermodynamics performance parameters which are defined and discussed in this paper. These parameters include the output, efficiency, fuel flow rate and air flow rate in relation to variations in the ambient temperature, pressure ratio, turbine entry temperature, compressor isentropic efficiency and turbine isentropic efficiency. [Spanish] Se presenta el comportamiento termodinamico de las centrales termicas que operan con turbinas de gas al variar los siguientes parametros: condiciones ambientales, relacion de presiones, temperatura de los gases a la entrada de la turbina de gas y las eficiencias isentropicas de compresion y expansion. Los resultados obtenidos son la eficiencia termica, el trabajo motor generado, el exceso de aire y los flujos de combustible en funcion de los parametros citados anteriormente. El analisis parametrico se realizo con el simulador TURBOGAS disenado en el laboratorio de ingenieria termica e hidraulica aplicada de la seccion de estudios de posgrado e investigacion de la escuela superior de Ingenieria Mecanica y Electrica del Instituto Politecnico Nacional.

  8. Parámetros de calidad durante la cosecha de durazno (Prunus persica L. Batsch cv. “Rubidoux”

    Directory of Open Access Journals (Sweden)

    Lisney Alessandra Bastidas Parrado

    2015-03-01

    Full Text Available El durazno es una fruta de importancia agrícola como parte de los cultivos caducifolios producidos en Colombia; su calidad y aceptacion comercial, asi como el momento de la cosecha, estan definidos en funcion de sus características fisicoquimicas. Esta investigacion tuvo como propósito caracterizar algunos parametros de calidad de durazno variedad Rubidoux durante el periodo de cosecha, a partir de la seleccion hecha por operarios en campo, de acuerdo al color de la piel como indicador de madurez. Durante seis semanas de la cosecha se evaluaron muestras de frutos, considerando aspectos como peso fresco, contenido de solidos solubles (oBrix, categoria comercial de acuerdo al diametro ecuatorial y color del fruto. Se registro un peso fresco promedio de 130,7 g por fruto, con un contenido de solidos solubles promedio de 11,8 oBrix, parametro que incremento progresivamente de la semana uno a la cinco. La clasificacion visual por el color de la piel permitio definir siete categorias, tres predominaron durante la cosecha (pinton, pinton-maduro y maduro, estos se correspondieron con el contenido de solidos solubles; es asi como el analisis de varianza mostro diferencias estadisticas entre oBrix y el color de piel. Durante el periodo evaluado, se cosecharon con mayor frecuencia duraznos pintones y frutos con diametro entre 60 mm a 70 mm.

  9. Modelización de una situación real con tabletas: el experimento de la pelota

    Directory of Open Access Journals (Sweden)

    Miriam Ortega Pons

    2015-07-01

    Full Text Available En este estudio presentamos una experiencia llevada a cabo en una clase de 1o de bachillerato con un modelo de enseñnanza diseñnado para trabajar los conceptos de familia de funciones y parametro a traves de la modelizacion. Dicho modelo tiene la caracterstica de que los datos usados son obtenidos por los propios estudiantes en el aula usando tabletas y de que incluye elementos que permiten guiarlos en la realizacion de una buena gestion del proceso de modelizacion. El analisis posterior de los resultados revelo que la realizacion de un analisis cualitativo previo del fenomeno estudiado así como los conocimientos que poseen los estudiantes sobre las famlias de funciones y el signicado de los parametros son elementos clave en la gestion y el control de todo el proceso. Tambien obtuvimos informacion acerca de las concepciones de los alumnos sobre los conceptos de altura y tiempo.

  10. Environmental psychology in the bioclimatic design; La psicologia ambiental en el diseno bioclimatico

    Energy Technology Data Exchange (ETDEWEB)

    Cubillas Talamante, Lorena Gpe [Facultad de Arquitectura, Universidad Autonoma de Baja California, Mexicali, Baja California (Mexico)

    2005-07-01

    The bioclimatic design profits of the natural resources for the improvement of the construction quality as well as the user's life. The combination of these two concepts within the architectonic design generates an interesting duality to consider within the understanding of the user's physical and psychological environment and the obtaining of a correlation of reality and dreams. Environmental psychology is focused on the researching of the psychological effects of the architectonic environment on the human experience and behavior. Human behavior works under parameters established during its development. Through the habits and styles of life practiced in childhood those parameters establish themselves to later on obtain satisfiers in the search of the life quality of human beings. [Spanish] El diseno bioclimatico aprovecha los recursos naturales para el mejoramiento de la calidad de la construccion y vida del usuario. La combinacion de estos dos conceptos dentro del diseno arquitectonico, genera dualidad interesante de entender el medio ambiente fisico y psicologico de los usuarios y obtener una identificacion entre la realidad y los suenos. La psicologia ambiental se ha enfocado a investigar sobre la relacion de los efectos psicologicos del ambiente construido o arquitectonico sobre la conducta y la experiencia humana. La conducta humana trabaja bajo parametros establecidos durante el desarrollo del mismo, a traves de los habitos y estilos de vida desde su infancia van marcando esos parametros que despues sirven para lograr satisfactores en la busqueda de la calidad de vida de los seres humanos.

  11. Mass textures and wolfenstein parameters from breaking the flavour permutational symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Mondragon, A; Rivera, T. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico,Mexico D.F. (Mexico); Rodriguez Jauregui, E. [Deutsches Elekronen-Synchrotron, Theory Group, Hamburg (Germany)

    2001-12-01

    We will give an overview of recent progress in the phenomenological study of quark mass matrices, quark flavour mixings and CP-violation with emphasis on the possibility of an underlying discrete, flavour permutational symmetry and its breaking, from which realistic models of mass generation could be built. The quark mixing angles and CP-violating phase, as well as the Wolfenstein parameters are given in terms of four quark mass ratios and only two parameters (Z{sup 1}/2, {phi}) characterizing the symmetry breaking pattern. Excellent agreement with all current experimental data is found. [Spanish] Daremos una visita panoramica del progreso reciente en el estudio fenomenologico de las matrices de masas y de mezclas del sabor de los quarks y la violacion de PC, con enfasis en la posibilidad de que, subyacentes al problema, se halle una simetria discreta, permutacional del sabor y su rompimiento a partir de las cuales se puedan construir modelos realistas de la generacion de las masas. Los angulos de mezcla de los quarks y la fase que viola CP, asi como los parametros de Wolfenstein se dan en terminos de cuatro razones de masas de los quarks y solamente dos parametros (Z{sup 1}/2, {phi}) que caracterizan el patron del rompimiento de la simetria. Los resultados se encuentran en excelente acuerdo con todos los datos experimentales mas recientes.

  12. Environmental psychology in the bioclimatic design; La psicologia ambiental en el diseno bioclimatico

    Energy Technology Data Exchange (ETDEWEB)

    Cubillas Talamante, Lorena Gpe [Facultad de Arquitectura, Universidad Autonoma de Baja California, Mexicali, Baja California (Mexico)

    2005-07-01

    The bioclimatic design profits of the natural resources for the improvement of the construction quality as well as the user's life. The combination of these two concepts within the architectonic design generates an interesting duality to consider within the understanding of the user's physical and psychological environment and the obtaining of a correlation of reality and dreams. Environmental psychology is focused on the researching of the psychological effects of the architectonic environment on the human experience and behavior. Human behavior works under parameters established during its development. Through the habits and styles of life practiced in childhood those parameters establish themselves to later on obtain satisfiers in the search of the life quality of human beings. [Spanish] El diseno bioclimatico aprovecha los recursos naturales para el mejoramiento de la calidad de la construccion y vida del usuario. La combinacion de estos dos conceptos dentro del diseno arquitectonico, genera dualidad interesante de entender el medio ambiente fisico y psicologico de los usuarios y obtener una identificacion entre la realidad y los suenos. La psicologia ambiental se ha enfocado a investigar sobre la relacion de los efectos psicologicos del ambiente construido o arquitectonico sobre la conducta y la experiencia humana. La conducta humana trabaja bajo parametros establecidos durante el desarrollo del mismo, a traves de los habitos y estilos de vida desde su infancia van marcando esos parametros que despues sirven para lograr satisfactores en la busqueda de la calidad de vida de los seres humanos.

  13. A study of the mechanism of certain heterogeneous catalytic processes using C{sup 14}-labelled compounds; Utilisation de composes marques au carbone-14 pour l'etude du mecanisme de certains processus catalytiques heterogenes; Issledovanie mekhanizma nekotorykh geterogenno-kataliticheskikh protsessov s primeneniem soedinenij, mechennykh uglerodom-14; Estudio del mecanismo de algunos procesos de catalisis heterogenea con ayuda de compuestos marcados con carbono-14

    Energy Technology Data Exchange (ETDEWEB)

    Isagulyants, G V; Balandin, A A

    1962-03-15

    An investigation is made of the method of calculating individual phase velocities for parallel, consecutive and parallel-consecutive reactions from kinetic data obtained by the use of labelled atoms. The method is used for calculating individual phase velocities in the decomposition reaction of isopropyl alcohol into vanadium trioxides, dehydrogenations of butane-butylene mixtures and dehydrations of ethyl alcohol. Compounds containing C{sup 14} were used in this study. (author) [French] Le memoire expose une methode par laquelle on calcule les vitesses a differents stades dans les reactions paralleles, consecutives et paralleles-consecutives en se servant de donnees cinetiques obtenues par l'utilisation d'atomes indicateurs. Cette methode est utilisee pour le calcul des vitesses a differents stades de la decomposition de l'alcool isopropylique par le trioxyde de vanadium, de la deshydrogenation des melanges butane-butylene et de la deshydratation de l'alcool ethylique. Pour ces travaux, on a utilise des composes contenant du carbone-14. (author) [Spanish] Se describe un metodo de calculo de las velocidades correspondientes a las distintas etapas de una serie de reacciones paralelas, consecutivas y paralelo-consecutivas, partiendo de datos cineticos obtenidos mediante atomos marcados. El metodo se aplica a la determinacion de las velocidades de las reacciones de descomposicion del alcohol isopropilico por el trioxido de vanadio, de deshidrogenacion de mezclas de butano y buteno y de deshidratacion del alcohol etilico. El trabajo se llevo a cabo con ayuda de compuestos marcados con carbono-14. (author) [Russian] Rassmotren metod rascheta skorostej otdel'nykh stadij dlya parallel'nykh, konsekutivnykh i parallel'no-konsekutivnykh reaktsij, iskhodya iz kineticheskikh dannykh, poluchennykh s primeneniem mechenykh atomov. Metod primenen k raschetu skorostej otdel'nykh stadij v reaktsii razlozheniya izopropilovogo spirta na trekhokisi vanadiya, degidrogenizatsii butan

  14. The 2030 Scenarios (Chapter 6 in 'A vision of year 2030 on the use of the renewable energies in Mexico'); Los escenarios a 2030 (Capitulo 6 en 'Una vision al 2030 de la utilizacion de las energias renovables en Mexico')

    Energy Technology Data Exchange (ETDEWEB)

    Mulas del Pozo, Pablo [Universidad Autonoma Metropolitana, Mexico, D.F. (Mexico)

    2005-08-15

    The quantification of the different scenarios that have been determined is an exercise that has as an aim illustrating on the interrelation between the parameters that affect the behavior of the energy system, more than having magnitudes on the size of the supply and energy demand for each type of primary energy. The credibility of the numbers is very small due to the many uncertainties in the long-term assumptions. The true value of the exercise is to understand the interrelationship of the different parameters that can affect the system and the impacts that can cause variants of the same. Also it is spoken of the obtained results with LEAP system that are related to the energy demand to year 2030 as well as the composition of the primary energy basket to be used and, the results obtained with the simplified method where, the determination of the demand in 2030 for both scenarios was made in simplified form through the determination of the values of the GIP and those of the energy intensity, being based on the rates of growth supposed for these two parameters in both periods to be considered. [Spanish] La cuantificacion de los diferentes escenarios que se han determinado es un ejercicio que tiene como fin el ilustrar sobre la interrelacion entre los parametros que afectan el comportamiento del sistema energetico, mas que el tener magnitudes sobre el tamano de la oferta y demanda energetica para cada tipo de energetico primario. La credibilidad de los numeros es muy pequena debido a las grandes incertidumbres en los supuestos a largo plazo. El verdadero valor del ejercicio es entender la interrelacion de los diferentes parametros que pueden afectar al sistema y los impactos que pueden causar variantes de los mismos. Tambien se habla de los resultados obtenidos con el sistema LEAP que se encuentran relacionados con la demanda energetica al 2030 asi como la composicion de la canasta de energeticos primarios a utilizarse y, los resultados obtenidos con el metodo

  15. The 2030 Scenarios (Chapter 6 in 'A vision of year 2030 on the use of the renewable energies in Mexico'); Los escenarios a 2030 (Capitulo 6 en 'Una vision al 2030 de la utilizacion de las energias renovables en Mexico')

    Energy Technology Data Exchange (ETDEWEB)

    Mulas del Pozo, Pablo [Universidad Autonoma Metropolitana, Mexico, D.F. (Mexico)

    2005-08-15

    The quantification of the different scenarios that have been determined is an exercise that has as an aim illustrating on the interrelation between the parameters that affect the behavior of the energy system, more than having magnitudes on the size of the supply and energy demand for each type of primary energy. The credibility of the numbers is very small due to the many uncertainties in the long-term assumptions. The true value of the exercise is to understand the interrelationship of the different parameters that can affect the system and the impacts that can cause variants of the same. Also it is spoken of the obtained results with LEAP system that are related to the energy demand to year 2030 as well as the composition of the primary energy basket to be used and, the results obtained with the simplified method where, the determination of the demand in 2030 for both scenarios was made in simplified form through the determination of the values of the GIP and those of the energy intensity, being based on the rates of growth supposed for these two parameters in both periods to be considered. [Spanish] La cuantificacion de los diferentes escenarios que se han determinado es un ejercicio que tiene como fin el ilustrar sobre la interrelacion entre los parametros que afectan el comportamiento del sistema energetico, mas que el tener magnitudes sobre el tamano de la oferta y demanda energetica para cada tipo de energetico primario. La credibilidad de los numeros es muy pequena debido a las grandes incertidumbres en los supuestos a largo plazo. El verdadero valor del ejercicio es entender la interrelacion de los diferentes parametros que pueden afectar al sistema y los impactos que pueden causar variantes de los mismos. Tambien se habla de los resultados obtenidos con el sistema LEAP que se encuentran relacionados con la demanda energetica al 2030 asi como la composicion de la canasta de energeticos primarios a utilizarse y, los resultados obtenidos con el metodo

  16. Geoelectrical characterization of a site with hydrocarbon contamination caused by pipeline leakage

    Energy Technology Data Exchange (ETDEWEB)

    Delgado-Rodriguez, Omar; Shevnin, Vladimir; Ochoa-Valdes, Jesus [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico); Ryjov, Albert [Moscow State Geological Prospecting Academy, Moscow (Russian Federation)

    2006-01-15

    contaminadas dentro del acuifero. El acuifero y el acuitardo fueron caracterizados con base en su resistividad, contenido de arcilla, porosidad y capacidad de intercambio cationico. Los valores de resistividad fueron recalculados a valores de parametros petrofisicos utilizando un algoritmo de inversion que toma en cuenta la salinidad del agua de poro. En zonas no contaminadas los parametros petrofisicos estimados a partir de datos de resistividad presentan valores cercanos a los reales, mientras que en zonas contaminadas se obtienen valores anomalos. Efectos similares de la influencia contaminacion sobre los parametros petrofisicos fueron encontrados en laboratorio realizando mediciones de resistividad en muestras de arena limpia y contaminada.

  17. Influence of housing density on the number of road containers for selective collection. Methodology and analysis of the results; Influenza della densita' abitativa sul numero dei contenitori stradali per la raccolta differenziata: metodologia e analisi dei risultati

    Energy Technology Data Exchange (ETDEWEB)

    Florio, G. [Calabria Univ., Arcavata di rende, RC (Italy). Dipt. di Meccanica; Greco, G. [MI.GA. S.r.l., Rende, CS (Italy); Giordano, R.

    1999-10-01

    In planning the network of road bins for selective collection, housing density or the relationship between built-up area and population living, is significant. The influence of the above parameter on planning the system is formalised in this work and an evaluation method valid for the number of bins required for a generic material is developed. Application to a real case has enable the obtainable results with the proposed procedure to be indicate. [Italian] Nel presente lavoro viene formalizzata l'influenza del parametro sul dimensionamento del sistema della raccolta differenziata e viene presentato un metodo divalutazione del numero di contenitori valido per un generico materiale. Un'applicazione ad un caso reale ha permesso di evidenziare i risultati ottenuti con la procedura proposta.

  18. Mushrooms preserved by the combined effect of refrigeration and gamma irradiation; Champinones conservados por el efecto combinado de refrigeracion e irradiacion gamma

    Energy Technology Data Exchange (ETDEWEB)

    Domenech, A M; Bauza de Faliti, M; Bocklet, M F

    1991-12-31

    In this work, the combined effect of refrigeration and gamma irradiation on diverse physical parameters to be measured in mushrooms was studied. Mushrooms (Agaricus Campestris), `bisporus` variety, of closed cap, were used. From the treatments tested, it was concluded that 0.5 KGy is the most suitable dosis to delay elongation, cap opening, stem length and surface moss growth. (Author). [Espanol] En este trabajo se ha estudiado el efecto combinado de la refrigeracion y la irradiacion gamma sobre los diversos parametros fisicos medibles en el champinon. Se utilizaron hongos del genero Agaricus Campestris, variedad bisporus, de sombrero cerrado. De los tratamientos ensayados, se ha demostrado tener efecto util la dosis de 0,5 KGy ya que se logro retardar crecimiento, apertura del sombrero, largo del pie y desarrollo de mohos en superficie. (Autor).

  19. Corrosion detection and monitoring in steam generators by means of ultrasound; Deteccion y monitoreo de corrosion por medio de ultrasonido en generadores de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Chacon Nava, Jose G; Calva, Mauricio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico); Fuentes Samaniego, Raul [Universidad Autonoma de Nuevo Leon (Mexico); Peraza Garcia, Alejandro [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1988-12-31

    The tube and component failures in steam generators due to corrosion cause huge economical losses. In this article the internal corrosion processes (hydrogen attack) and high temperature corrosion are described, as well as the ultrasound techniques used for its detection. The importance of obtaining corrosion rates, which are fundamental parameters for the detection of the tube`s residual life. The purpose is to prevent possible failures that would diminish the power plant availability. [Espanol] Las fallas de tuberia en componentes de generadores de vapor debidas a corrosion ocasionan considerables perdidas economicas. En este articulo se describen los procesos de corrosion interna (ataque por hidrogeno) y corrosion en alta temperatura, asi como tecnicas de ultrasonido empleadas para su deteccion. Se destaca la importancia de obtener valores de velocidad de corrosion, que es un parametro fundamental para la determinacion de la vida residual de tuberias. El proposito es poder prevenir posibles fallas que disminuyan la disponibilidad de centrales termoelectricas.

  20. Gaussian plume model for the SO{sub 2} in a thermoelectric power plant; Modelo de pluma gaussiano para el SO{sub 2} en una central termoelectrica

    Energy Technology Data Exchange (ETDEWEB)

    Reyes L, C; Munoz Ledo, C R [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1993-12-31

    The Gaussian Plume Model is an analytical extension to simulate the dispersion of the SO{sub 2} concentration at ground level as a function of the emission changes in the spot sources, as well as the pollutant dispersion in the Wind Rose, when the necessary parameters are fed. The model was elaborated in a personal computer and the results produced are generated in text form. [Espanol] El modelo de pluma gaussiano es una extension analitica para simular la dispersion de las concentraciones de SO{sub 2} a nivel del piso en funcion de los cambios de las emisiones en las fuentes puntuales, asi como, la dispersion del contaminante en la rosa de los vientos cuando se le alimentan los parametros necesarios. El modelo fue elaborado en una computadora personal y los resultados que proporciona los genera en modo texto.

  1. Modeling and identification for the adjustable control of generation processes; Modelado e identificacion para el control autoajustable de procesos de generacion

    Energy Technology Data Exchange (ETDEWEB)

    Ricano Castillo, Juan Manuel; Palomares Gonzalez, Daniel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1990-12-31

    The recursive technique of the method of minimum squares is employed to obtain a multivariable model of the self regressive mobile mean type, needed for the design of a multivariable, self-adjustable controller self adjustable multivariable. In this article the employed technique and the results obtained are described with the characterization of the model structure and the parametric estimation. The convergency velocity curves are observed towards the parameters` numerical values. [Espanol] La tecnica recursiva del metodo de los minimos cuadrados se emplea para obtener un modelo multivariable de tipo autorregresivo de promedio movil, necesario para el diseno de un controlador autoajustable muitivariable. En el articulo, se describe la tecnica empleada y los resultados obtenidos con la caracterizacion de la estructura del modelo y la estimacion parametrica. Se observan las curvas de la velocidad de convergencia hacia los valores numericos de los parametros.

  2. On line chemical analyzers for high purity steam and water, applied to steam power plants; Analizadores quimicos en linea para agua y vapor de alta pureza, aplicados a centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Perez, Ruth [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1990-12-31

    This article presents a general overview of the advances in the subject of on line analyzers of chemical parameters for high purity water and steam and specifies which ones are commercially available. Also are mentioned besides, the criteria nowadays applied for the selection of the sites for sample grabbing and the analysis that is necessary to perform in each point, depending on the power plant type and the treatment administered (phosphates-Ph coordinated or AVT treatment). [Espanol] El articulo presenta un panorama general de los avances que en materia de analizadores de parametros quimicos en linea para agua y vapor de alta pureza, y especifica cuales estan disponibles en forma comercial. Se citan, ademas los criterios que se aplican actualmente para seleccionar los puntos de toma de muestra y los analisis que es necesario efectuar en cada punto, dependiendo del tipo de central y del tratamiento que se le administre (fosfatos-pH coordinado o tratamiento AVT).

  3. Introduzione all'analisi qualitativa dei sistemi dinamici discreti e continui

    CERN Document Server

    Squassina, Marco

    2016-01-01

    Il testo è stato concepito per la struttura degli attuali corsi di laurea in Biologia, Matematica, Matematica Applicata, Ingegneria, Scienze Naturali e Mediche. Esso si concentra sugli aspetti qualitativi delle equazioni differenziali come limitatezza o illimitatezza delle soluzioni, esistenza o non esistenza di orbite periodiche, stabilità o instabilità dei punti di equilibrio, biforcazione del sistema al variare di un parametro, robustezza del sistema in presenza di perturbazioni. L'analisi qualitativa di sistemi dinamici discreti e continui è un argomento tecnicamente accessibile anche agli studenti di primo livello e consente di collegare, combinare ed esercitare nozioni che provengono dall'algebra, dal calcolo differenziale di base e dalla geometria elementare, stimolando l'intuizione matematica. Il volume si caratterizza per due aspetti: quello induttivo e quello figurativo. L'approccio induttivo si basa su un'ampia gamma di problemi risolti e pensati per introdurre, gradualmente, sia le conoscenze ...

  4. On line chemical analyzers for high purity steam and water, applied to steam power plants; Analizadores quimicos en linea para agua y vapor de alta pureza, aplicados a centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Perez, Ruth [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1989-12-31

    This article presents a general overview of the advances in the subject of on line analyzers of chemical parameters for high purity water and steam and specifies which ones are commercially available. Also are mentioned besides, the criteria nowadays applied for the selection of the sites for sample grabbing and the analysis that is necessary to perform in each point, depending on the power plant type and the treatment administered (phosphates-Ph coordinated or AVT treatment). [Espanol] El articulo presenta un panorama general de los avances que en materia de analizadores de parametros quimicos en linea para agua y vapor de alta pureza, y especifica cuales estan disponibles en forma comercial. Se citan, ademas los criterios que se aplican actualmente para seleccionar los puntos de toma de muestra y los analisis que es necesario efectuar en cada punto, dependiendo del tipo de central y del tratamiento que se le administre (fosfatos-pH coordinado o tratamiento AVT).

  5. Modeling and identification for the adjustable control of generation processes; Modelado e identificacion para el control autoajustable de procesos de generacion

    Energy Technology Data Exchange (ETDEWEB)

    Ricano Castillo, Juan Manuel; Palomares Gonzalez, Daniel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1989-12-31

    The recursive technique of the method of minimum squares is employed to obtain a multivariable model of the self regressive mobile mean type, needed for the design of a multivariable, self-adjustable controller self adjustable multivariable. In this article the employed technique and the results obtained are described with the characterization of the model structure and the parametric estimation. The convergency velocity curves are observed towards the parameters` numerical values. [Espanol] La tecnica recursiva del metodo de los minimos cuadrados se emplea para obtener un modelo multivariable de tipo autorregresivo de promedio movil, necesario para el diseno de un controlador autoajustable muitivariable. En el articulo, se describe la tecnica empleada y los resultados obtenidos con la caracterizacion de la estructura del modelo y la estimacion parametrica. Se observan las curvas de la velocidad de convergencia hacia los valores numericos de los parametros.

  6. Search for direct CP violation in charged kaons with NA48/2 experiment

    CERN Document Server

    Lamanna, Gianluca; Pierazzini, Giuseppe

    In questa tesi e’ discussa l’analisi dell’asimmetria della slope lineare in decadimenti dei kaoni carichi in tre pioni. In particolare e’ presentata l’analisi nel processo K->pi pi0 pi0. La misura di tale asimmetria e’ una misura dell’effetto di violazione diretta di CP nei kaoni carichi. Fino ad oggi la violazione di questa importante simmetria è stata stabilita soltanto nei mesoni neutri. Preziosi indicazioni sulla presenza di effetti provenienti da nuova fisica oltre il modello standard, potrebbe giungere da una misura del parametro Ag al livello di 10E-4 . Nel lavoro dopo una breve introduzione teorica, è descritta la tecnica sperimentale utilizzata nell’esperimento NA48/2 al CERN, la presa dati e la complessa strategia di misura con particolare enfasi sulle tecniche adottate per ridurre il contributo di effetti indotti da asimmetrie strumentali. Il risultato finale della tesi è oggetto di pubblicazione scientifica.

  7. Obtention of the pressed states by canonic transformations in the quantum space phase; Obtencion de estados comprimidos mediante transformaciones canonicas en el espacio fase cuantico

    Energy Technology Data Exchange (ETDEWEB)

    Zuniga Segundo, A. [Instituto Politecnico Nacional, Mexico, D.F. (Mexico)

    2001-10-01

    In this work we introduce squeezed states with real and complex squeezing parameters directly obtained in the coherent-representation of the harmonic oscillator in quantum phase space. By means of the Fourier transform, we recover the usual coordinate states and compare these states with those obtained by another method in the coordinate representation. In addition we also describe numerically its time evolution in quantum phase space and the variances Q and P. [Spanish] En este trabajo presentamos estados comprimidos con parametros de compresion reales y complejos, obtenidos directamente en la representacion de estado coherente del oscilador armonico en el espacio fase cuantico. Por medio de una transformada de Fourier recuperamos los estados en la representacion de coordenadas y los comparamos con aquellos obtenidos por otro metodo. Ademas describimos numericamente sus evoluciones temporales en el espacio fase cuantico y calculamos las varianzas de Q y P.

  8. Corrosion detection and monitoring in steam generators by means of ultrasound; Deteccion y monitoreo de corrosion por medio de ultrasonido en generadores de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Chacon Nava, Jose G.; Calva, Mauricio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico); Fuentes Samaniego, Raul [Universidad Autonoma de Nuevo Leon (Mexico); Peraza Garcia, Alejandro [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1987-12-31

    The tube and component failures in steam generators due to corrosion cause huge economical losses. In this article the internal corrosion processes (hydrogen attack) and high temperature corrosion are described, as well as the ultrasound techniques used for its detection. The importance of obtaining corrosion rates, which are fundamental parameters for the detection of the tube`s residual life. The purpose is to prevent possible failures that would diminish the power plant availability. [Espanol] Las fallas de tuberia en componentes de generadores de vapor debidas a corrosion ocasionan considerables perdidas economicas. En este articulo se describen los procesos de corrosion interna (ataque por hidrogeno) y corrosion en alta temperatura, asi como tecnicas de ultrasonido empleadas para su deteccion. Se destaca la importancia de obtener valores de velocidad de corrosion, que es un parametro fundamental para la determinacion de la vida residual de tuberias. El proposito es poder prevenir posibles fallas que disminuyan la disponibilidad de centrales termoelectricas.

  9. Libertad religiosa y Estado Constitucional

    Directory of Open Access Journals (Sweden)

    Samuel Abad Yupanqui

    2008-12-01

    Full Text Available El presente articulo pretende examinar la evolución del debate constitucional sobre las relaciones Estado–Iglesia en nuestro pais, el actual diseno de estas relaciones a partir de lo dispuesto por el texto constitucional vigente y el Acuerdo suscrito con la Iglesia Catolica en julio de 1980, asi como los alcances de un proyecto de ley que pretende regular la libertad e igualdad religiosas. Asumiendo tal perspectiva recordaremos algunos antecedentes constitucionales que nos muestran por donde se ha encaminado el debate; y examinaremos los principios que orientan la relacion Iglesia-Estado, desde un enfoque de derechos fundamentales y en el marco de la indispensable afirmacion de un Estado Constitucional de Derecho. Ello es particularmente relevante en un pais como el nuestro en donde determinadas concepciones religiosas pretenden establecerse como unico parametro para la adopcion de aquellas politicas publicas respecto a las cuales la Iglesia tiene una posicion definida.

  10. Strategies for energy saving in buildings by means of automatic control; Estrategias de ahorro de energia en inmuebles mediante el control automatico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Trujillo, Oscar [Johnson Controls de Mexico S. A. de C. V., Mexico, D. F. (Mexico)

    1998-12-31

    In this paper some of the measures and strategies for energy saving that can be applied in different types of buildings, mainly in hotels and office buildings, are presented. The proposed actions are accomplished with the aid of the automatic control equipment and the operation and/or maintenance personnel that supervises and establishes the control parameters of each one of the strategies than are focused to the appropriate utilization of the electric energy. [Espanol] En este documento se presentan algunas de las medidas y estrategias de ahorro de energia que pueden ser aplicadas en diferentes tipos de inmuebles, principalmente en hoteles y en edificios de oficinas. Las acciones propuestas son realizadas con la ayuda del equipo de control automatico y del personal de operacion y/o mantenimiento quien supervisa y establece los parametros de control de cada una de las estrategias que son destinadas a la buena utilizacion de la energia electrica.

  11. RADIATION MODEL FOR PREDICTING TEMPERATURE EVOLUTION IN SOLAR COOKER

    Directory of Open Access Journals (Sweden)

    FARID CHEJNE

    2011-01-01

    Full Text Available Un modelo matemático que describe y simula el comportamiento térmico de una estufa solar fue desarrollado en base en la analogía de resistencias aléctricas. El modelo matemático incluye los tres diferentes mecanismos de transferencia de calor entre las diferentes superfi cies de la cocina solar y su entorno. El modelo matemático se utilizó para predecir la generación de entropía y de su efi ciencia; tambien, fue utilizado para evaluar los parametros de diseño de una estufa solar tipo caja. Los datos experimentales y teóricos fueron comparados satisfactoriamente.

  12. Studio di prototipo di calorimetro per neutroni per l'esperimento ALICE

    CERN Document Server

    Arnaldi, R; Cicalò, C; Cortese, P; De Falco, A; Dellacasa, G; De Marco, N; Gallio, M; Macciotta, P; Masoni, A; Musso, A; Oppedisano, C; Piccotti, A; Puddu, G; Scomparin, E; Siddi, S; Serci, E; Soave, C; Usai, G L; Vercellin, Ermanno

    1999-01-01

    ALICE e uno dei quattro esperimenti previsti ad LHC, al CERN, il cui scopo e lo studio delle osservabili che danno informazioni rilevanti sulla formazione del quark gluon plasma, che potrebbe essere prodotto in collisioni centrali Pb-Pb, di energia nel centro di massa di 5.5 A TeV.Il parametro di impatto di tali collisioni verra determinato grazie ad un insieme di calorimetri per protoni e neutroni che misureranno l'energia portata in avanti dai nucleoni non interagenti(spettatori).E' stato costruito un prototipo di calometro per neutroni, formato da piani di fibre di quarzo, posti a 45 gradi rispetto all'asse del fascio e inframmezzati da piani di materiale passivo denso(tungsteno). La luce Cerenkov prodotta nelle fibre dallo sciame sviluppato nel materiale passivo,viene raccolta da guide ottiche in aria.Verranno presentati i rilustati di un test previsto al CERN SPS per il luglio 1999.

  13. Gaussian plume model for the SO{sub 2} in a thermoelectric power plant; Modelo de pluma gaussiano para el SO{sub 2} en una central termoelectrica

    Energy Technology Data Exchange (ETDEWEB)

    Reyes L, C.; Munoz Ledo, C. R. [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1992-12-31

    The Gaussian Plume Model is an analytical extension to simulate the dispersion of the SO{sub 2} concentration at ground level as a function of the emission changes in the spot sources, as well as the pollutant dispersion in the Wind Rose, when the necessary parameters are fed. The model was elaborated in a personal computer and the results produced are generated in text form. [Espanol] El modelo de pluma gaussiano es una extension analitica para simular la dispersion de las concentraciones de SO{sub 2} a nivel del piso en funcion de los cambios de las emisiones en las fuentes puntuales, asi como, la dispersion del contaminante en la rosa de los vientos cuando se le alimentan los parametros necesarios. El modelo fue elaborado en una computadora personal y los resultados que proporciona los genera en modo texto.

  14. Strategies for energy saving in buildings by means of automatic control; Estrategias de ahorro de energia en inmuebles mediante el control automatico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Trujillo, Oscar [Johnson Controls de Mexico S. A. de C. V., Mexico, D. F. (Mexico)

    1999-12-31

    In this paper some of the measures and strategies for energy saving that can be applied in different types of buildings, mainly in hotels and office buildings, are presented. The proposed actions are accomplished with the aid of the automatic control equipment and the operation and/or maintenance personnel that supervises and establishes the control parameters of each one of the strategies than are focused to the appropriate utilization of the electric energy. [Espanol] En este documento se presentan algunas de las medidas y estrategias de ahorro de energia que pueden ser aplicadas en diferentes tipos de inmuebles, principalmente en hoteles y en edificios de oficinas. Las acciones propuestas son realizadas con la ayuda del equipo de control automatico y del personal de operacion y/o mantenimiento quien supervisa y establece los parametros de control de cada una de las estrategias que son destinadas a la buena utilizacion de la energia electrica.

  15. Spherical galaxies.

    Science.gov (United States)

    Telles, J. E.; de Souza, R. E.; Penereiro, J. C.

    1990-11-01

    RESUMEN. Presentamos fotometria fotografica de 8 objetos y espectrosco- pla para 3 galaxias, las cuales son buenos candidatos para galaxias esfericas. Los resultados fotometricos se presentan en la forma de iso- fotas y de perfiles radiales promedlo, de los cuales se derivan para- metros estructurales. Estas observaciones combinadas con parametros di- namicos obtenidos de observaciones espectrosc6picas, son consistentes con el plano fundamental derivado por Djorgovski y Davis (1987). ABSTRACT. We present photographic surface photometry for 8 objects and spectroscopy for 3 galaxies which are good candidates for spherical galaxies. Photometric results are presented in the form of isophotes and mean radial profiles from which we derived structural parameters. These observations combined with dynamical parameters obtained from spectroscopic observations are consistent with the fundamental plane derived by Djorgovski and Davis (1987). Keq wo : CALAXIES-ELLIPTICAL

  16. Importance of the dynamic module of soil rigidity in the analysis of the stability problems by the action of the seismic waves; Importancia del modulo dinamico de rigidez del suelo en el analisis de los problemas de estabilidad por la accion de las ondas sismicas

    Energy Technology Data Exchange (ETDEWEB)

    Zeevaert-Wiechers, L. [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    2000-09-01

    The object of the present paper is to motivate engineers interested in soil mechanics and in soil dynamics to use, apply and develop seismic-geodynamics principles in the professional practice of seismic engineering, as well as to study and investigate dynamic soil parameters. For this purpose the author presents two types of equipment that he has used with success during several decades. [Spanish] El objetivo de este trabajo es el de motivar a los ingenieros interesados en mecanica y dinamica de suelos, al uso, aplicacion y desarrollo de la sismo-geodinamica en la practica profesional de la ingenieria sismica, asi como al estudio e investigacion de los parametros dinamicos del suelo. Para este fin, el autor presenta dos equipos que ha usado durante varias decadas.

  17. Importance of the dynamic module of rigidity of the ground in the analysis of the problems of stability by the action of the seismic waves; Importancia del modulo dinamico de rigidez del suelo en el analisis de los problemas de estabilidad por la accion de las ondas sismicas

    Energy Technology Data Exchange (ETDEWEB)

    Zeevaert Wiechers, L. [Facultad de Ingenieria, UNAM, Mexico, D.F. (Mexico)

    2000-09-01

    The object of the present paper is to motivate engineers interested in soil mechanics and in soil dynamics to use, apply and develop seismic-geodynamics principles in the professional practice of seismic engineering, as well as to study and investigate dynamic soil parameters. For this purpose, the author present two types of equipment he has used with success during several decades. [Spanish] El objetivo de este trabajo es el de motivar a los ingenieros interesados en mecanica y dinamica de suelos, al uso, aplicacion y desarrollo de la sismo-geodinamica en la practica profesional de la ingenieria sismica, asi como al estudio e investigacion de los parametros dinamicos del suelo. Para este fin, el autor presenta dos equipos que ha usado con exito durante varias decadas.

  18. Geochemical model of a geothermal system: an approach on the analytical uncertainty; Modelo geoquimico de sistema geotermico: un enfoque sobre la incertidumbre analitica

    Energy Technology Data Exchange (ETDEWEB)

    Pal Verma, Mahendra [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2008-07-01

    A procedure was developed to consider the analytical uncertainty in each parameter of geochemical analysis of geothermal fluid. The estimation of the uncertainty is based on the results of the geochemical analyses of geothermal fluids (numbered from the 0 to the 14), obtained within the framework of the comparisons program among the geochemical laboratories in the last 30 years. Also the propagation of the analytical uncertainty was realized in the calculation of the parameters of the geothermal fluid in the reservoir, through the methods of interval of uncertainty and GUM (Guide to the expression of Uncertainty of Measurement). The application of the methods is illustrated in the pH calculation of the geothermal fluid in the reservoir, considering samples 10 and 11 as separated waters at atmospheric conditions. [Spanish] Se desarrollo un procedimiento para estimar la incertidumbre analitica en cada parametro de analisis geoquimico de fluido geotermico. La estimacion de la incertidumbre esta basada en los resultados de los analisis geoquimicos de fluidos geotermicos (numerados del 0 al 14), obtenidos en el marco del programa de comparaciones entre los laboratorios geoquimicos en los ultimos 30 anos. Tambien se realizo la propagacion de la incertidumbre analitica en el calculo de los parametros del fluido geotermico en el yacimiento, a traves de los metodos de intervalo de incertidumbre y GUM (Guide to the expression of Uncertainty of Measurement). La aplicacion de los metodos se ilustra en el calculo de pH del fluido geotermico en el yacimiento, considerando las muestras 10 y 11 como aguas separadas a las condiciones atmosfericas.

  19. Importance of the validation of saving technologies of electric power; Importancia de la validacion de tecnologias ahorradoras de energia electrica

    Energy Technology Data Exchange (ETDEWEB)

    Valer Negrete, Adrian [Programa de Ahorro de Energia del Sector Electrico (PAESE), Comision Federal de Electricidad (Mexico)

    2003-07-01

    Within the Programs of Energy Saving it is fundamental the search and application of new technologies, with which this saving can be obtained, selected with base in their technical characteristics that allow to reduce to the consumptions and demands of power, without damaging the electric networks nor the transformers of the Comision Federal de Electricidad. It is important that the investments which are made count on attractive periods of capital recovery, in comparison with the useful life of the product, reason why the knowledge and price of the new technologies will be parameters to consider in an important manner, creating the need of conducting tests that verify the veracity of the information of the supplier, resulting in certain cases, the change of design of these technologies, so that thus they fulfill the engaged characteristics. This paper indicates the characteristics that the new saving technologies of electrical energy must fulfill and the tests and parameters to consider their evaluation. [Spanish] Dentro de los Programas de Ahorro de Energia es fundamental la busqueda y aplicacion de nuevas tecnologias, con las que se pueda obtener dicho ahorro, seleccionadas con base en sus caracteristicas tecnicas que permitan reducir los consumos y demandas de potencia, sin danar las redes ni transformadores de la Comision Federal de Electricidad. Es importante que las inversiones que se realicen cuenten con periodos de recuperacion de capital atractivos, comparados con la vida util del producto, por lo que el conocimiento y precio de las nuevas tecnologias seran parametros a considerar de manera importante, creandose la necesidad de realizar pruebas que verifiquen la veracidad de la informacion del proveedor, resultando en determinados casos, el cambio de diseno de dichas tecnologias, para que asi cumplan las caracteristicas prometidas. Este trabajo indica las caracteristicas que deben cumplir las nuevas tecnologias ahorradoras de energia electrica y las

  20. Quantitative prediction of strong motion for a potential earthquake fault

    Directory of Open Access Journals (Sweden)

    B. CHOUET

    1977-06-01

    Full Text Available RIASSUNTO. - Questa nota descrive un nuovo metodo per calcolare le registrazioni
    accelerografìehe per una data regione sismica in base alle leggi fisiche
    usando le informazioni relative alla tettonica ed alle proprietà fisiche della faglia
    sismica.
    Il metodo si basa su di un nuovo modello sismico, chiamato « modello
    b a r r i e r a » , caratterizzato da cinque parametri focali: lunghezza della faglia,
    larghezza, scorrimento massimo, velocità di rottura ed intervallo di barriera.
    I primi tre parametri possono essere vincolati dalla tettonica a placche, il
    quarto parametro è approssimativamente una costante. Il parametro più importante,
    che controlla l'accelerazione del terremoto, è l'ultimo, l'intervallo « barriera ».
    Vi sono tre metodi per valutare 1' « intervallo barriera » per una data
    regione sismica: 1 misurazione in superficie dello scorrimento attraverso fratture
    di faglia; 2 creazione di un modello che si adatti all'osservazione di
    campi vicini e lontani; 5 una legge che regoli i dati per i piccoli terremoti nella
    regione.
    Gli intervalli barriera sono stati valutati per una dozzina di terremoti e
    per quattro regioni sismiche, per mezzo dei tre metodi suindicati. I risultati
    preliminari ottenuti per la California suggeriscono che l'intervallo barriera
    possa essere determinato quando sia dato il massimo scorrimento. La relazione
    tra l'intervallo barriera ed il massimo scorrimento varia da una regione sismica
    all'altra. Ad esempio, l'intervallo appare insolitamente lungo per Kilanea (Hawaii,
    il che può spiegare perché traccia di forte scorrimento del terreno sia stata
    osservata soltanto nell'area epicentrale del terremoto delle Isole Hawaii del 29
    novembre 1975.

  1. Studies on the Optimal behavior of Energy Storage in Reservoirs of a Hydroelectric system; Estudios sobre el comportamiento optimo del almacenamiento de energia en embalses de sistema hidroelectrico

    Energy Technology Data Exchange (ETDEWEB)

    Macedo Faria, Breno; Franco Barbosa, Paulo Sergio [Universidad Estatal de Campinas (Brazil)

    2002-09-01

    This work aims at studying the results of an optimisation model applied to the Paranaiba river basin, Brazil. This system is made by the junction of three river branches located in a region with a well-defined seasonal hydrological behavior. The ratio between the total energy storage in the system and the active storage for every reservoir is evaluated from the optimal operational results. This relationship allows recognizing systematic patterns on the relative use for every reservoir, when compared to the entire system. The main parameters that define reservoir behavior are identified, with highlights on the position of the power station in the cascade, the relationship between the river flow and the active storage, and the installed capacity of the power station. In addition, the parameter hydrological scenario is also another factor that defines the relative use of the reservoirs. [Spanish] El modelo del presente trabajo tiene como objetivo estudiar los resultados de una optimizacion para el sistema hidroelectrico de la cuenca del rio Paranaiba, Brasil, la cual esta formada por la confluencia de tres rios en una region de distribucion de lluvias bien definidas en terminos hidrologicos. Se analiza la relacion entre la energia total almacenada en el sistema y el volumen util de cada embalse a partir de los resultados operativos optimos. Esta relacion permite identificar resultados sistematicos en lo que se refiere a la utilizacion de cada embalse, en comparacion con el uso del sistema como un todo. Se identifican los principales parametros responsables por el comportamiento de los embalses, destacando la influencia de la posicion de la central hidroelectrica en la cascada, de la relacion caudal/volumen util y de la potencia de central. Ademas, el parametro escenario hidrologico tambien es otro factor determinante en el uso relativo de los embalses.

  2. A new aeolian generator for Mexico; Un nuevo generador eolico para Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Voronin, Boris; Gomez Reyna, Jose Antonio; Zerquera Izquierdo, Mariano David; Cardenas Grajales, Juan Jose; Zamora Quintana, Laura Angelica [Universidad de Guadalajara (Mexico)

    2009-07-01

    The use of wind kinetic energy to produce electrical energy is one of the most powerful alternatives for the human being, to avoid the risk of being in the threshold of the age of stone. In the present work, different types from aero generators are analyzed and a new generator developed by one of the authors of this article is presented. Its high efficiency is presented in comparison with the helical generators that at the moment are dominant in the construction of Aeolian mills. Perspectives of exploitation of the kinetic energy of the wind in Mexico are analyzed. A resolution model of the problem of obtaining constant parameters of electrical output, to conditions of variable mechanical parameters of entrance is shown. An example is shown of the construction of Aeolian parks that can cover all the needs of electrical energy in Mexico. [Spanish] El uso de la energia cinetica del viento para la obtencion de la energia electrica, es una de las alternativas mas poderosas para el ser humano, para evitar el riesgo de estar al umbral de la edad de piedra. En el trabajo presente, se analizan diferentes tipos de aerogeneradores y se presenta un nuevo generador desarrollado por uno de los autores de este articulo. Se muestra su alta eficiencia en comparacion con los generadores helicoidales que actualmente son dominantes en la construccion de molinos eolicos. Se analizan perspectivas de aprovechamiento de la energia cinetica del viento en Mexico. Se muestra un modelo de resolucion del problema de la obtencion de parametros de salida electricos constantes, a condiciones de los parametros mecanicos de entrada variables. Se muestra un ejemplo de la construccion de parques eolicos que pueden cubrir todas las necesidades de energia electrica en Mexico.

  3. Litiniferous pegmatites from Itinga-Aracuai region, Minas Gerais, Brazil

    International Nuclear Information System (INIS)

    Silva Sa, J.H. da.

    1977-01-01

    This work explains the study of more a hundred pegmatites from Itinga and Aracuai, in middle Jequitinhonha. This area have cassiterite, tantalite-columbite, semiprecious stones ad lithium minerals. The lithium ores are the most economic importance. The predominate rocks are quartz-mica schist, rich in cordierite. Geochronological dating, by the Rb-Sr method, show ages about 650 m.a. to schist and 520 m.a. to the granites. Was dated muscovites from two pegmatites by K-Ar method showing ages about 4677+- 18 m.a and 490 +- 12 m.a. The pegmatites was classified in simple and complex, based in mineralogical and structural criterion. In the complex pegmatites was determinated notable accessory minerological association, in which the principal are lithium ores-petalite, spodumene, lepidolite, ambligonite, the cesium ore-polucite-and cassiterite, tantalite-columbite, and great variety of turmaline. Genetically the pegmatites are related with the granites of this region, with present high tenor of the lithium, cesium and beryllium, comparate with the normal granites. (C.D.G.) [pt

  4. Cesium residue leachate migration in the tailings management area of a mine site : predicted vs. actual

    Energy Technology Data Exchange (ETDEWEB)

    Solylo, P.; Ramsey, D. [Wardrop Engineering, Winnipeg, MB (Canada). Mining and Minerals Section

    2009-07-01

    This paper reported on a study at a cesium products facility (CPF) that manufactures a non-toxic cesium-formate drilling fluid. The facility operates adjacent to a pollucite/tantalum/spodumene mine. The CPF was developed as a closed system, with the residue tailings slurry from the CPF process discharged to doublelined containment cells. Groundwater monitoring has shown that leachate has affected near-surface porewater quality within the tailings management area (TMA). Elevated concentrations of calcium, sulphate, strontium, cesium, and rubidium were used to identify the leachate. Porewater at the base of the tailings and in the overburden beneath the tailings has not been affected. A geochemical investigation was initiated to determine how the leachate behaves in the groundwater/tailings porewater system. Over the past 7 years of residue placement in the TMA, the footprint of the residue placement area has changed, making the comparison of predicted versus actual rate of leachate migration very subjective and difficult to quantify. Based solely on the analytical data, the source of the leachate is unknown, either from the original residue pile or the 2007 residue placement area. For purposes of long term residue management, an investigation of the geochemical behaviour of residue leachate in the groundwater/tailings system of the TMA is currently underway. 5 refs., 1 tab., 2 figs.

  5. Crystallization characteristics and physico-chemical properties of glass–ceramics based on Li2O–ZnO–SiO2 system

    Directory of Open Access Journals (Sweden)

    Saad M. Salman

    2017-09-01

    Full Text Available Glass materials based on lithium zinc silicate system of the composition 24Li2O–20ZnO–56SiO2 LZS (mol% were prepared and converted to glass–ceramics using controlled heat-treatment schedules. The LZS base glass system was modified by addition of Al2O3 and MO/ZnO replacements where MO = CaO, CdO and SrO oxides. Several crystalline phases were developed, including lithium zinc orthosilicate, α-quartz, β-spodumene solid solution, lithium meta and disilicate, Ca-wollastonite, Cd or Sr metasilicate, and Sr-zinc silicate of hardystonite type. The effects of crystallization process on some properties, like thermal expansion coefficient (TEC, chemical stability, and density of glass–ceramics were evaluated. The TEC of crystalline samples varied from 72 × 10−7 to 149 × 10−7 K−1, 25–600 and density values in the range, 2.67–3.29 g/cm3. The addition of Al2O3 and MO/ZnO replacements in the base glass led to improve the chemical durability of the glass–ceramics samples. As a result of the thermal and physico-chemical properties of the studied glass–ceramic, the materials acquire excellent properties and can be used to seal a variety of different metals and alloys.

  6. Applications of lithium in nuclear energy

    Energy Technology Data Exchange (ETDEWEB)

    Oliviera, Glaucia A.C. de; Bustillos, José O.V.; Ferreira, João C.; Bergamaschi, Vanderlei S.; Moraes, Rafaeli M. de; Gimenez, Maíse P.; Miyamoto, Flavia K.; Seneda, José A., E-mail: glaucia.oliveira@ipen.br, E-mail: ovega@ipen.br, E-mail: jcferrei@ipen.br, E-mail: vsberga@ipen.br, E-mail: rafaeli.medeiros.moraes@gmail.com, E-mail: maisepastore@hotmail.com, E-mail: fla.kimiyamoto@gmail.com, E-mail: jaseneda@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP), Paulo, SP (Brazil)

    2017-07-01

    Lithium is a material of great interest in the world, it is found in different minerals on Earth's crust (spodumene, lepidolite, amblygonite and petalite) also in salt pans. This element belongs to alkaline group and has two natural isotopes: Li-6 and Li-7. In the nuclear field, lithium isotopes are used for different purposes. The Li-6 is applied in the production of energy, because its section of shock is larger than the other isotope. The Li-7 regulates the pH in refrigerant material in the primary circuits of the Pressurized Water Nuclear Reactor (PWR). In nuclear reactor, lithium is used as a heat transfer due its boiling temperature (1342°C), making it an excellent thermal conductor. However, to reach all these applications, lithium must have high purity (> 99%). The main processes to reach a high purity level of lithium employee a combination of solvent extraction and ion exchange process, to obtain its salts or ending with chemical electrolysis of its chlorides to obtain its pure metal. This work presents a review of new applications of Lithium in Nuclear Energy and its purification and enrichment processes. (author)

  7. Applications of lithium in nuclear energy

    International Nuclear Information System (INIS)

    Oliviera, Glaucia A.C. de; Bustillos, José O.V.; Ferreira, João C.; Bergamaschi, Vanderlei S.; Moraes, Rafaeli M. de; Gimenez, Maíse P.; Miyamoto, Flavia K.; Seneda, José A.

    2017-01-01

    Lithium is a material of great interest in the world, it is found in different minerals on Earth's crust (spodumene, lepidolite, amblygonite and petalite) also in salt pans. This element belongs to alkaline group and has two natural isotopes: Li-6 and Li-7. In the nuclear field, lithium isotopes are used for different purposes. The Li-6 is applied in the production of energy, because its section of shock is larger than the other isotope. The Li-7 regulates the pH in refrigerant material in the primary circuits of the Pressurized Water Nuclear Reactor (PWR). In nuclear reactor, lithium is used as a heat transfer due its boiling temperature (1342°C), making it an excellent thermal conductor. However, to reach all these applications, lithium must have high purity (> 99%). The main processes to reach a high purity level of lithium employee a combination of solvent extraction and ion exchange process, to obtain its salts or ending with chemical electrolysis of its chlorides to obtain its pure metal. This work presents a review of new applications of Lithium in Nuclear Energy and its purification and enrichment processes. (author)

  8. Lithium in the Natural Waters of the South East of Ireland.

    Science.gov (United States)

    Kavanagh, Laurence; Keohane, Jerome; Cleary, John; Garcia Cabellos, Guiomar; Lloyd, Andrew

    2017-05-26

    The South East of Ireland (County Carlow) contains a deposit of the valuable lithium-bearing mineral spodumene (LiAl(SiO₃)₂). This resource has recently attracted interest and abstractive mining in the area is a possibility for the future. The open cast mining of this resource could represent a potential hazard in the form of metalliferous pollution to local water. The population of County Carlow is just under 60,000. The local authority reports that approximately 75.7% of the population's publicly supplied drinking water is abstracted from surface water and 11.6% from groundwater. In total, 12.7% of the population abstract their water from private groundwater wells. Any potential entry of extraneous metals into the area's natural waters will have implications for people in county Carlow. It is the goal of this paper to establish background concentrations of lithium and other metals in the natural waters prior to any mining activity. Our sampling protocol totaled 115 sites along five sampling transects, sampled through 2015. From this dataset, we report a background concentration of dissolved lithium in the natural waters of County Carlow, surface water at x ¯ = 0.02, SD = 0.02 ranging from 0 to 0.091 mg/L and groundwater at x ¯ = 0.023, SD = 0.02 mg/L ranging from 0 to 0.097 mg/L.

  9. Crystallization characteristics and physico-chemical properties of glass–ceramics based on Li2O–ZnO–SiO2 system

    International Nuclear Information System (INIS)

    Salman, Saad M.; Salama, Samia N.; Abo-Mosallam, Hany A.

    2017-01-01

    Glass materials based on lithium zinc silicate system of the composition 24Li2O–20ZnO–56SiO2 LZS (mol%) were prepared and converted to glass–ceramics using controlled heat-treatment schedules. The LZS base glass system was modified by addition of Al2O3 and MO/ZnO replacements where MO=CaO, CdO and SrO oxides. Several crystalline phases were developed, including lithium zinc orthosilicate, α-quartz, β-spodumene solid solution, lithium meta and disilicate, Ca-wollastonite, Cd or Sr metasilicate, and Sr-zinc silicate of hardystonite type. The effects of crystallization process on some properties, like thermal expansion coefficient (TEC), chemical stability, and density of glass–ceramics were evaluated. The TEC of crystalline samples varied from 72×10−7 to 149×10−7K−1, 25–600 and density values in the range, 2.67–3.29g/cm3. The addition of Al2O3 and MO/ZnO replacements in the base glass led to improve the chemical durability of the glass–ceramics samples. As a result of the thermal and physico-chemical properties of the studied glass–ceramic, the materials acquire excellent properties and can be used to seal a variety of different metals and alloys. [es

  10. Investigation of Thermal Expansion of a Glass Ceramic Material with an Extra-Low Thermal Linear Expansion Coefficient

    Science.gov (United States)

    Kompan, T. A.; Korenev, A. S.; Lukin, A. Ya.

    2008-10-01

    The artificial material sitall CO-115M was developed purposely as a material with an extra-low thermal expansion. The controlled crystallization of an aluminosilicate glass melt leads to the formation of a mixture of β-spodumen, β-eucryptite, and β-silica anisotropic microcrystals in a matrix of residual glass. Due to the small size of the microcrystals, the material is homogeneous and transparent. Specific lattice anharmonism of these microcrystal materials results in close to zero average thermal linear expansion coefficient (TLEC) of the sitall material. The thermal expansion coefficient of this material was measured using an interferometric method in line with the classical approach of Fizeau. To obtain the highest accuracy, the registration of light intensity of the total interference field was used. Then, the parameters of the interference pattern were calculated. Due to the large amount of information in the interference pattern, the error of the calculated fringe position was less than the size of a pixel of the optical registration system. The thermal expansion coefficient of the sitall CO-115M and its temperature dependence were measured. The TLEC value of about 3 × 10-8 K-1 to 5 × 10-8 K-1 in the temperature interval from -20 °C to +60 °C was obtained. A special investigation was carried out to show the homogeneity of the material.

  11. Surface crystallization in a Li{sub 2}O-ZrO{sub 2}-SiO{sub 2}-Al{sub 2}O{sub 3} glass; Cristalizacao de superficie em vidro do sistema Li{sub 2}O-ZrO{sub 2}-SiO{sub 2}-Al{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Antonio Pedro Novaes de; Teixeira, Alexandre Henrique Bortolotto; Venturelli, Hugo Henrique, E-mail: bortolotto_teixeira@yahoo.com.br, E-mail: venturellihugo@gmail.com, E-mail: antonio.pedro@ufsc.br [Universidade Federal de Santa Catarina (VITROCER/PGMAT/UFSC), Florianopolis, SC (Brazil). Laboratorio de Materiais Vitroceramicos; Montedo, Oscar Rubem Klegues, E-mail: oscar.rkm@gmail.com [Universidade do Extremo Sul Catarinense (CERTEC/PPGCEM/UNESC), Criciuma, SC (Brazil). Grupo de Pesquisa em Ceramica Tecnica

    2017-04-15

    Growth kinetics of crystallized surface layer in a LZSA glass composition, 11.7Li{sub 2}O·12.6ZrO{sub 2}·68.6SiO{sub 2}·7.1Al{sub 2}O{sub 3} (wt%), was studied. For the production of the LZSA glass, it was used commercial raw materials (Li{sub 2}CO{sub 3}, ZrSiO{sub 4}, SiO{sub 2}, Al{sub 2}O{sub 3}) which were mixed and melted at 1550 °C for 120 min and then poured into a metallic mold. Samples of the obtained glass were cut and subjected to heat treatments at different temperatures (825 - 925 °C) and times (30 - 150 min) for formation and growth of crystalline layer. Cross-sections of the heat-treated samples were ground and polished such that images of the formed crystallized layers could be visualized and measured by microscopy. Results showed that it is possible to obtain LZSA glasses with crystallized layers formed by β-spodumene, zircon and lithium silicate, which present thicknesses between 13 and 665 μ and grow at rates varying from 0.4 to 4.8 μm/min in the studied temperature range. (author)

  12. Solid state reaction in alumina nanoparticles/LZSA glass-ceramic composites

    International Nuclear Information System (INIS)

    Montedo, O.K.; Oliveira, A.N. de; Raupp-Pereira, F.

    2016-01-01

    Full text: The aim of this work is to present results related to solid state reactions on LZSA glass-ceramic composites containing alumina reinforcement nano-particles. A LZSA (Li2O-ZrO2-SiO2-Al2O3) glass-ceramic has been prepared by sintering of powders and characterized. Composites containing 0 to 77 vol.% of alumina nanoparticles (27-43 nm APS, 35 m2.g-1 SSA) and a 16.9Li2O•5.0ZrO2•65.1SiO2•8.6Al2O3 glass-ceramic matrix have been prepared. X-ray diffractometry studies have been performed in order of investigating the solid state reactions occurring in LZSA-based composites. Results of the XRD patterns have been related to the coefficient of thermal expansion (CTE), Young modulus, and dielectric constant, showing that, in comparison with the glass-ceramic composition, the composites showed a decrease of CTE with the alumina concentration increasing, due to the increasing of beta-spodumeness formation (solid solution of beta-spodumene, Li2O.Al2O3.4-10SiO2). The performance of the glass-ceramic was improved with the alumina nano-particles addition, showing potential of using in the preparation of Low Thermal Co-fired Ceramics (LTCC). (author)

  13. Tradição letrada e cinema mudo: em torno de algumas crônicas mexicanas de começos do século XX

    Directory of Open Access Journals (Sweden)

    Miriam V. Gárate

    2008-12-01

    Full Text Available Durante o período em que o cinema surge e se desenvolve como espetáculo mudo, a reflexão acerca de suas as relações com a escrita e, em um sentido mais amplo, com a linguagem verbal, organiza-se basicamente em torno a três eixos: graus de afinidade ou discrepância existentes entre os gêneros literários utilizados como fonte e os atributos da imagem cinematográfica; função dos letreiros nesse contexto; potencialidades e limitações "inerentes" às linguagens cinético-visual e verbal. O tratamento dado a essas questões em algumas crônicas mexicanas das primeiras décadas do século XX revela as tensões internas, resistências e mudanças de ótica dos setores letrados perante a nova arte.Durante el período en que el cine surge y se desarrolla como espectáculo mudo, la reflexión acerca de sus relaciones con la escritura y, en un sentido amplio, con el lenguaje verbal, se organiza básicamente en torno a tres ejes: grados de afinidad o discrepancia existentes entre los géneros literarios utilizados como fuente y los atributos de la imagen cinematográfica; función de los letreros en ese contexto; potencialidades y limitaciones "inherentes" a los lenguajes cinetico-visual y verbal. El tratamiento dado a estas cuestiones en algunas crónicas mexicanas de las primeras décadas del siglo XX revela las tensiones internas, resistencias y cambios de óptica de los sectores letrados frente al nuevo arte.During the period in which the cinema emerges and develops as a silent spectacle, the reflection about its relation with the written language and, in a broader sense, with verbal language, is basically organized around three axes: degrees of affinity or discrepancy among the literary genres used as sources and the attributes of cinematographic language; the function of subtitles in this context; the potentialities and limitation "inherent" to the visual-kinetic and verbal languages. The way these issues were dealt with in the Mexican

  14. Synthesis and characterization of PdAg as a catalyst for oxygen reduction reaction in acid medium; Sintesis y caracterizacion de PdAg como catalizador para la reaccion de reduccion de oxigeno en medio acido

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Casillas, D. C.; Vazquez-Huerta, G.; Solorza-Feria, O. [Centro de Investigacion y de Estudios Avanzados del IPN, Mexico D.F. (Mexico)]. E-mail: dcmartinez@cinvestav.mx

    2009-09-15

    una solucion de H{sub 2}SO{sub 4} 0.5 M a 25 grados centigrados. Las respuestas electroquimicas corriente-potencial fueron comparadas con las del paladio y platino. Los resultados cineticos mostraron un incremento en el desempeno del electrocatalizador bimetalico conteniendo Ag en comparacion con el Pd puro, pero menor al obtenido con Pt nanometrico. Las pendientes de Tafel que se obtuvieron son cercanas a los 120 mV dec-1 semejante a lo reportado para Pt y Pd y para otros electrocatalizadores base Ru.

  15. Lanthanide oxide and phosphate nanoparticles for thermometry and bimodal imaging =

    Science.gov (United States)

    Debasu, Mengistie Leweyehu

    Nesta tese relatam-se estudos de fotoluminescencia de nanoparticulas de oxidos e fosfatos dopados com ioes trivalentes de lantanideos, respectivamente, nanobastonetes de (Gd,Eu)2O3 e (Gd,Yb,Er)2O3 e nanocristais de (Gd,Yb,Tb)PO4, demonstrando-se tambem aplicacoes destes materiais em revestimentos inteligentes, sensores de temperatura e bioimagem. Estuda-se a transferencia de energia entre os sitios de Eu3+ C2 e S6 dos nanobastonetes Gd2O3. A contribuicao dos mecanismos de transferencia de energia entre sitios para o tempo de subida 5D0(C2) e descartada a favor da relaxacao directa 5D1(C2) 5D0(C2) (i.e., transferencia de energia entre niveis). O maior tempo de decaimento do nivel 5D0(C2) nos nanobastonetes, relativamente ao valor medido para o mesmo material na forma de microcristais, e atribuido, quer a existencia de espacos livres entre nanobastonetes proximos (factor de enchimento ou fraccao volumica), quer a variacao do indice de refraccao efectivo do meio em torno dos ioes Eu3+. A dispersao de nanobastonetes de (Gd,Eu)2O3 em tres resinas epoxi comerciais atraves da cura por UV permite obter nanocompositos epoxi- (Gd,Eu)2O3. Relatam-se estudos cineticos e das propriedades termicas e de fotoluminescencia destes nanocompositos. Estes, preservam as tipicas propriedades de emissao do Eu3+, mostrando o potencial do metodo de cura por UV para obter revistimentos inteligentes e fotoactivos. Considera-se um avanco significativo a realizacao de uma nanoplataforma optica, incorporando aquecedor e termometro e capaz de medir uma ampla gama de temperaturas (300-2000 K) a escala nano, baseada em nanobastonetes de (Gd,Yb,Er)2O3 (termometros) cuja superficie se encontra revestida com nanoparticulas de ouro. A temperature local e calculada usando, quer a distribuicao de Boltzmann (300-1050 K) do racio de intensidades da conversao ascendente 2H11=2!4I15=2/4S3=2!4I15=2, quer a lei de Planck (1200-2000 K) para uma emissao de luz branca atribuida a radiacao do corpo negro

  16. Modeling of the shrinkage kinetics of coffee berries during drying = Modelagem da cinética de contração de frutos de café durante a secagem

    Directory of Open Access Journals (Sweden)

    Gabriel Henrique Horta Oliveira

    2011-07-01

    Full Text Available The effects of drying conditions on the shrinkage of Coffea arabica L., cultivar Catuai Vermelho, were studied. An exponential model derived from the kinetic model was used to describe the shrinkage kinetics. In addition, an equation was proposed to describe the relationship between the superficial areas and weights of the coffee berries. Coffee berries were dried at temperatures (T of 35, 45, 55 and 65oC and at relative humidities (ƒÓ of 25, 35, 45 and 55%, forming 16 different sets of conditions, with an initial moisturecontent for all conditions of 2.27 dry basis (d.b., dried until 0.11 d.b. Changes in the product dimensions were measured continuously during drying. Surface area-to-volume ratio values increased with moisture content decrease. The model was suitable for representing the shrinkage kinetics, as well the empirical equation for predicting surface area. Temperature had a greater influence over the constant rate of change of the characteristic dimension (k values than ƒÓ. Activation energies were also determined to have magnitudes of 39.31, 37.32, 36.28 and 36.22 kJ mol-1 for relative humidities of 25, 35, 45and 55%, respectively. Neste trabalho foi estudado o efeito das condicoes de secagem sobre a contracao de frutos de cafe (Coffea arabica L., cultivar Catuai Vermelho. Um modelo exponencial derivado do modelo cinetico foi utilizado para descrever a cinetica da contracao. Ademais, uma equacao foi proposta para descrever a relacao entre a area superficial e a massa dos frutos de cafe. Frutos de cafe foram secos as temperaturas de (T de 35, 45, 55 e 65oC, juntamente com umidades relativas (ƒÓ de 25, 35, 45 e 55%, totalizando 16 condicoesdiferentes, com um teor de agua inicial de 2,27 base seca (b.s., secos ate 0,11 b.s. As alteracoes nas dimensoes do produto foram mensuradas continuamente durante a secagem. Os valores de relacao superficie-volume aumentaram com a diminuicao do teor de agua. Omodelo foi adequado para

  17. Hydrogen and energy recovery by gasification of petroleum coke from heavy crude refining; Recuperacion de hidrogeno y energia mediante gasificacion de coques de petroleo provenientes de refinacion de crudos pesados

    Energy Technology Data Exchange (ETDEWEB)

    Paniagua-Rodriguez, J.C [Universidad Michoacana de San Nicolas de Hidalgo, Morelia, Michoacan (Mexico); Jimenez-Garcia, G. [Instituto Tecnologico del Valle de Morelia, Morelia, Michoacan (Mexico); Maya-Yescas, R. [Universidad Michoacana de San Nicolas de Hidalgo, Morelia, Michoacan (Mexico)]. E-mail: rmayay@umich.mx

    2013-03-15

    Heavy oils exhibit high yields to bottom-of barrel products (low commercial value); depending on the metals content and on carbon residue the upgrading of bottoms could follow either hydroprocessing or carbon rejection. In particular the Mexican Maya, which is the most refined crude in Mexico, is upgraded by carbon rejection via delayed coking of vacuum residue. In order to obtain acceptable economic profit, it is necessary to transform that carbon (mainly petroleum coke) into useful higher added value products. Coke gasification could be used to obtain hydrogen and/or energy (preferable electrical), via the reaction of coke molecules with oxygen, carbon dioxide and water. Departing from the empiric formulas of five petroleum cokes, a kinetic scheme that consists of three linearly independent stoichiometric equations was recently developed; by including the enthalpy of each reaction and considering the gasification reactor as adiabatic, it is possible to predict product stream composition and high pressure steam that could be generated by the process. [Spanish] Los crudos pesados exhiben rendimientos altos a productos de-fondo-de-barril (de bajo valor comercial); dependiendo del contenido de metales y del residuo carbonoso, la mejora de fondos puede llevarse a cabo por hidrotratamiento o rechazo de carbon. En particular el crudo Maya, que es el mas refinado en Mexico, se mejora via rechazo de carbon por coquizacion retardada del residuo de vacio. A fin de obtener ganancias aceptables, es necesario transformar ese carbon (coque de petroleo, principalmente) en producto util de alto valor agregado. La gasificacion de coque puede usarse para obtener hidrogeno y/o energia (electrica de preferencia), via la reaccion de moleculas de coque con oxigeno, dioxido de carbono y agua. Recientemente se desarrollo un esquema cinetico que consiste de tres reacciones linealmente independientes, partiendo de las formulas empiricas de cinco coques de petroleo; incluyendo la entalpia

  18. RuPd, RuCo, PdCo and RuPdCo materials as candidates for cathode catalyzers in PEM fuel cells; Materiales RuPd, RuCo, PdCo y RuPdCo como candidatos a catalizadores catodicos en celdas de combustible tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Leyva Noyola, Fatima; Solorza Feria, Omar [Centro de Investigacion y Estudios Superiores del IPN, Mexico, D.F. (Mexico)]. E-mail: fleyva@cinvestav.mx

    2009-09-15

    This work reports on the catalytic activity of RuPd, RuCo, PdCo and RuPdCo material for oxygen reduction reaction (ORR). These materials were synthesized using chemical reduction with NaBH{sub 4} as a reducing agent in THF, in ambient temperature and pressure conditions. The evaluation of the catalytic activity was done using cyclic voltamperometry (CV) and rotary disc electrode (RDE) in H{sub 2}SO{sub 4} 0.5 M. The kinetic results showed that the electrochemical reaction involves 4 electrons and the transfer of the first electron is the determinant stage. The values of {alpha}, i0 and the Tafel slope were very similar for the four materials studied, around 0.4, 5x10{sup -6} mA cm{sup -2} and 60 mV dec-1, respectively. Although these values are less than those reported for nanostructured platinum, they are better than those reported for other materials such as pure Pd, which enables them to be considered as cathode catalysts for a proton exchange membrane fuel cell. [Spanish] En este trabajo se reporta la actividad catalitica de los materiales RuPd, RuCo, PdCo y RuPdCo para la reaccion de reduccion de oxigeno (RRO). Estos materiales fueron sintetizados por el metodo de reduccion quimica, usando NaBH{sub 4} como agente reductor en THF, en condiciones de temperatura y presion ambiental. La evaluacion de la actividad catalitica fue realizada usando Voltamperometria Ciclica (VC) y Electrodo Disco Rotatorio (EDR) en H{sub 2}SO{sub 4} 0.5 M. Los resultados cineticos mostraron que la reaccion electroquimica procede por la via de 4 electrones y la etapa determinante es la transferencia del primer electron. Los valores de {alpha}, i0 y pendiente de Tafel fueron muy similares para los 4 materiales estudiados, siendo estos de alrededor de 0.4, 5x10{sup -6} mA cm{sup -2} y 60 mV dec{sup -1}, respectivamente. Sin embargo, aun cuando estos valores son menores que los reportados para platino nanoestructurado, son mejores que los reportados para otros materiales como el Pd puro

  19. Analysis of the variation effect of the mass in an aeolian shock absorber; Analisis del efecto de la variacion de la masa en un amortiguador eolico

    Energy Technology Data Exchange (ETDEWEB)

    Olivares Arriaga, Abraham

    2007-06-15

    instrumentation used for this aim. In chapter 5 the exposition of the design of experiments is realized and the first tests are reviewed to find the variation of the coefficient of damping with respect to the parameters that more affect it. The realized test results are shown in chapter 6. Finally in chapter 7, the conclusions and recommendations are given about this work. The main conclusion was that the mass is the factor that produces more variations of the damping coefficient. For the factors of the length and the moment of inertia a significant variation of the damping is not produced. [Spanish] En Mexico asi como en todo el mundo, las lineas de transmision de energia electrica se ven sometidas a vibracion que puede variar segun las caracteristicas del flujo del aire que las produce; para atenuar la vibracion y con esto, las fallas que se pudieran producir, principalmente fallas por fatiga o fractura, se han empleado desde la decada de 1930 amortiguadores eolicos tipo Stockbridge para disipar esta energia. Los principales parametros de un amortiguador tipo Stockbridge son: la masa del contrapeso, el momento de inercia, la longitud del cable mensajero, el coeficiente de amortiguamiento, las propiedades del cable mensajero, etc. Uno de los parametros mas importantes en el diseno de los amortiguadores eolicos es el coeficiente adimensional de amortiguamiento, por lo que es vital saber si este parametro varia conforme cambian las caracteristicas del amortiguador eolico. La presente investigacion se centra en conocer si existe o no una variacion en el coeficiente adimensional de amortiguamiento con respecto a los parametros del amortiguador. En el capitulo 1 se introduce al fenomeno de la vibracion eolica y a sus caracteristicas principales. Se describen los equipos utilizados para la reduccion de la vibracion eolica llamados amortiguadores tipo Stockbridge, y se plantean la definicion y el objetivo de las tesis. En el capitulo 2 se revisan dos modelos matematicos para describir

  20. Software library of meteorological routines for air quality models; Libreria de software de procedimientos meteorologicos para modelos de dispersion de contaminantes

    Energy Technology Data Exchange (ETDEWEB)

    Galindo Garcia, Ivan Francisco

    1999-04-01

    fundamental para llevar a cabo la evaluacion del impacto de fuentes fijas sobre la calidad del aire. Sin embargo, los modelos requieren cierta informacion relativa a la meteorologia de la zona que se desea modelar. Algunos de estos parametros requeridos se pueden medir directamente, pero otros deben ser estimados a partir de los datos medidos. Debido a esto, para realizar un estudio de modelacion de la contaminacion atmosferica, tambien es necesario contar con un conjunto de procedimientos, relaciones y programas de computo que permitan obtener todos los parametros meteorologicos y micrometeorologicos requeridos como datos de entrada por el modelo de dispersion de contaminantes especifico que se desee utilizar. El objetivo de este trabajo es la identificacion, establecimiento e implementacion de los metodos, relaciones y procedimientos que permiten la estimacion de los parametros meteorologicos y micrometeorologicos requeridos por los modelos de dispersion de contaminantes atmosfericos recomendados por la Agencia de Proteccion Ambiental de los Estados Unidos (US-EPA), a partir de diferentes niveles de disponibilidad de informacion meteorologica primaria. Para ello se realizo un estudio sobre los diferentes modelos de dispersion atmosferica, analizando, en particular, los datos meteorologicos que requieren. Asimismo, se llevo a cabo una caracterizacion de las estaciones meteorologicas mexicanas pertenecientes al Servicio Meteorologico Nacional, de donde se obtuvo informacion referente al tipo y calidad de los datos meteorologicos que producen, a fin de establecer, en particular, una metodologia especifica para la estimacion de los datos meteorologicos necesarios para la modelacion de la calidad del aire en Mexico. Los procedimientos de estimacion desarrollados se organizaron en una libreria de software que permite la integracion de un procesador meteorologico apropiado para cada modelo de dispersion (US-EPA) que se desee utilizar. Los procedimientos de estimacion se validaron

  1. Study of hydrogen in phthalocyanine semiconductors using muSR technique =

    Science.gov (United States)

    Duarte, Joao Pedro Piroto Pereira

    Este trabalho apresenta um estudo experimental dos semicondutores organicos Ftalocianina (H2Pc), Ftalocianina de Zinco (ZnPc) e Ftalocianina de Cobre (CuPc) por tecnicas de µSR, tendo-se obtido informacao detalhada sobre a estrutura electronica dos estados de carga formados pelo muao positivo nos tres compostos, e sobre as interaccoes dinamicas a que esses estados se encontram sujeitos. Os resultados do estudo indicam que nas ftalocianias com caracter nao magneticas H2Pc e ZnPc se da a formacao de tres radicais muonicos paramagneticos distintos. A estrutura hiperfina destes radicais, referidos como estados I, II e III, foi caracterizada atraves da medida dos parametros de acoplamento hipefino em conjunto com a parameterizacao da sua dependencia com a temperatura. Uma quarta componente paramagnetica do sinal µSR foi tambem identificada, mas sobre a qual nao foi possivel retirar conclusoes definitivas quanto a sua origem. Verificou-se que os parametros de acoplamento hiperfino isotropicos dos tres estados identificados se encontram numa regiao de valores entre os 100 e os 150MHz para os estados I e II, enquanto que para o estado III esta quantidade toma valores em torno de 10 MHz. A estrutura electronica de todos os estados possui simetria axial, caracterizada por parametros dipolares de cerca de 15MHz para os estados I e II, e 20MHz para o estado III. A origem dos estados I e II foi determinada como sendo devida a adicao de muonio a uma das ligacoes duplas existentes nos aneis benzenicos da periferia das moleculas de ftalocianina recorrendo a calculos de estrutura electronica, tendo-se verificado a existencia de um acoplamento entre a interaccao hiperfina desses estados e modos vibracionais desses aneis. A problematica da localizacao do estado III tambem foi abordada, tomando-se como hipotese mais provavel uma posicao intersticial entre duas moleculas de ftalocianina. O estudo das interaccoes dinamicas de spin destes tres estados revelou que o estado III esta

  2. Investigation of multi-phases dynamic systems by means of optical and electrochemical methods; Investigacion de sistemas dinamicos multifasicos mediante metodos opticos y electroquimicos

    Energy Technology Data Exchange (ETDEWEB)

    Sarmiento Martinez, Oscar

    2008-09-15

    de la degradacion metalica en muestras de aluminio durante los estados iniciales de procesos de oxidacion en soluciones acuosas, sin medir contacto fisico alguno. Adicionalmente, se desarrollo un modelo matematico el cual permite, a partir de los desplazamientos ortogonales que ocurren en la superficie del metal durante la reaccion anodica, encontrar la perdida o crecimiento del espesor de la capa metalica de la muestra a partir del conteo de franjas de interferencia. En la presente tesis doctoral, se presentan resultados experimentales y numericos referentes a ciertos procesos de corrosion en diferentes sistemas electroquimicos utilizando simultaneamente el monitoreo optico mediante interferometria de Michelson y el monitoreo electroquimico mediante curvas de polarizacion. Se analiza la informacion tanto cualitativa como cuantitativa de importantes parametros fisicos relacionados con los procesos de corrosion y su dinamica, asi como la formacion de patrones de interferencia cuyo contraste optico se pierde con el paso de tiempo, para subitamente reaparecer y con ello nuevamente la aparicion del patron de interferencia inicial. Por otro lado, se desarrollo un modelo matematico a partir del sistema optico-electroquimico, el cual permite cuantificar mediante parametros opticos la perdida de material o crecimiento de oxido en metales, permitiendo reproducir las curvas electroquimicas mediante el conteo de maximos de interferencia. Finalmente, y de acuerdo a conceptos de la teoria de sistemas dinamicos no lineales, se analizan y discuten los parametros fisicos dinamicos no lineales relativos a la existencia de soluciones complejas de tipo caotico con base en los datos obtenidos de los procesos de corrosion en soluciones acuosas e hidrocarburos observados durante el monitoreo optico-electroquimico de nuestro sistema.

  3. Design and construction of the prototype of a digital meter of single phase electric energy based in a microcontroller; Diseno y construccion del prototipo de un medidor digital de energia electrica monofasico basado en un microcontrolador

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Alonso, Ruben

    2003-10-15

    . Este medidor toma muestras de voltaje y corriente de ondas senoidales y las convierte a digital para realizar el procesamiento en tiempo real. El aparato esta construido en base al microcontrolador PIC16F874 de la tecnologia microchip. Todos los parametros medidos y calculados son visualizados en una pantalla de cristal liquido de 2 X 16 caracteres, tiene un menu donde se selecciona alguno de los parametros a conocer. En caso de falla de suministro de energia electrica, el medidor almacena el consumo de energia en memoria. El voltaje es medido desde 1 a 255 Vrms, la corriente desde 0.1 a 25.5 Arms, la potencia se muestra en 5 digitos desde 0 a 6502.5 watts, la energia se presenta con 5 digitos enteros y 5 decimales, desde 0 hasta 99999.99999 kWh, este valor se visualiza cada segundo, y el costo por el consumo se presenta desde 0 hasta 9999.9 pesos. Para la construccion del aparato se disenaron cuatro tarjetas que son: adquisicion de datos, acondicionamiento de la senal, procesamiento de la senal y presentacion de resultados, que se interconectan entre si para formar el medidor digital de energia electrica. Se desarrollaron rutinas en lenguaje ensamblador que calculan todos los parametros electricos descritos anteriormente y se ensamblaron en el microcontrolador donde se procesa la informacion.

  4. The influence of Al2O3, MgO and ZnO on the crystallization characteristics and properties of lithium calcium silicate glasses and glass-ceramics

    International Nuclear Information System (INIS)

    Salman, S.M.; Darwish, H.; Mahdy, E.A.

    2008-01-01

    The crystallization characteristics of glasses based on the Li 2 O-CaO-SiO 2 eutectic (954 ± 4 deg. C) system containing Al 2 O 3 , MgO and ZnO has been investigated by differential thermal analysis (DTA), X-ray diffraction analysis (XRD), and scanning electron microscopy (SEM). The partial replacement of Li 2 O by Al 2 O 3 and CaO by MgO or ZnO in the studied glass-ceramics led to the development of different crystalline phase assemblages, including lithium meta- and di-silicates, lithium calcium silicates, α-quartz, diopside, clinoenstatite, wollastonite, β-eucryptite ss, β-spodumene, α-tridymite, lithium zinc orthosilicate, hardystonite and willemite using various heat-treatment processes. The dilatometric thermal expansion of the glasses and their corresponding glass-ceramics were determined. A wide range of thermal expansion coefficient values were obtained for the investigated glasses and their corresponding crystalline products. The thermal expansion coefficients of the investigated glasses were decreased by Al 2 O 3 , MgO or ZnO additions. The α-values of the investigated glasses were ranged from (+18) to (+108) x 10 -7 K -1 (25-300 deg. C), while those of the glass-ceramics were (+3) to (+135) x 10 -7 K -1 (25-700 deg. C). The chemical durability of the glass-ceramics, towards the attack of 0.1N HCl solution, was markedly improved by Al 2 O 3 with MgO replacements. The composition containing 11.5 mol% Al 2 O 3 and 6.00 mol% MgO exhibited low thermal expansion values and good chemical durability

  5. Behavior of high efficiency electric motors; Comportamiento de motores electricos de alta eficiencia

    Energy Technology Data Exchange (ETDEWEB)

    Bonett, Austin H. [IEEE, (United States)

    2001-09-01

    The energy efficiency is one of the main parameters in the design of the industrial motors of general purpose; nevertheless, it is avoided that it is at the cost of the reliability or to the global performance of the motor. Exist user groups of this equipment that consider that, in the search of a greater efficiency, the useful life period is diminished and the characteristics of operation of the motor are affected. During the past last years, the author has studied the aspects of quality and reliability, as well as the operative advantages of the high efficiency motors and written down the increasing interest for these aspects. Also he has detected that a great number of users has realized that, additionally to the obvious energy saving, the efficient motor offers a greater reliability and a longer useful life in most of the industrial applications. The objective of this article is to present the differences in the quality levels, reliability and operation parameters of high efficiency squirrel cage type electrical motors with those of the motors of standard manufacture. [Spanish] La eficiencia energetica es uno de los principales parametros en el diseno de los motores industriales de proposito general; sin embargo, se evita que sea a costa de la confiabilidad o del desempeno global del motor. Existen grupos de usuarios de estos equipos que consideran que, en la busqueda de una mayor eficiencia, se disminuye el periodo de vida util y se afectan las caracteristicas de operacion del motor. Durante los ultimos anos, el autor ha estudiado los aspectos de calidad y confiabilidad, asi como las ventajas operativas de los motores de alta eficiencia y anotado el incremento del interes por estos aspectos. Tambien ha detectado que un gran numero de usuarios se ha dado cuenta que, adicionalmente a los obvios ahorros de energia, el motor eficiente ofrece una mayor confiabilidad y una vida util mas larga en la mayoria de las aplicaciones industriales. El objetivo de este

  6. A lidar study of atmospheric aerosols during two contrasting monsoon seasons

    Energy Technology Data Exchange (ETDEWEB)

    Devara, P.C.S.; Raj, P.E. [Indian Institute of Tropical Meteorology (India)

    1998-10-01

    The vertical profiles of the boundary-layer aerosols obtained with a bistatic argon ion lidar system at the Indian Institute of Tropical Meteorology (IITM), Pune, India, during two contrasting, successive south-west (summer) monsoon seasons of 1987 (weak monsoon year) and 1988 (active monsoon year) have been examined. The concurrent meteorological parameters such as temperature, relative humidity and rainfall over Pune have also been studied. It is noticed that the aerosol columnar content (integration of vertical profile throughout the height range) is greater during the active monsoon months and less during the weak monsoon months. Thus the monsoon season total rainfall during 1987 and 1988, apart from other meteorological parameters, shows close correspondence with the aerosol columnar content over the experimental station. A brief description of the lidar experimental setup and the database is given. The observed association between the aerosol columnar content and the monsoon activity is explained in terms of the environmental and meteorological conditions prevailing over Pune. [Spanish] Los perfiles verticales de los aerosoles de la capa fronteriza obtenidos mediante un sistema de Lidar biestatico de iones de argon en el Instituto de Meteorologia Tropical (IITM) en Pune, India, durante dos estaciones contrastantes y suscesivas del monzon del SW (verano) de 1987 (ano de monzon debil) y 1988 (ano activo de monzon) han sido estudiados. Los parametros meteorologicos concurrentes tales como temperatura, humedad relativa y lluvia en Pune, han sido tambien estudiados. Se observa que el contenido columnar de aerosoles (integracion del perfil vertical en toda la gama de alturas) es mayor durante los meses del monzon activo y menor en los meses del monzon debil. De manera que, el total de la lluvia monzonica durante 1987 y 1988, aparte de otros parametros meteorologicos, muestran una correspondencia intima con el contenido columnar de a erosoles sobre la estacion

  7. Effect of an axially-symmetric cyclonic vortex on the sea surface temperature in the Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Villanueva, E.E.; Mendoza, V.M.; Adem, J. [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)]. E-mail: eevu@atmosfera.unam.mx

    2006-04-15

    A model for the mixed layer of the Gulf of Mexico has been used to determine the effect that an idealized cyclonic vortex has in the sea surface temperature. The model consists of the equations of conservation of thermal energy and this of balance between mechanical energy and thermal energy, last based on the Kraus-Turner theory; both equations are vertically integrated in the mixed layer. As atmospheric forcing, we prescribe the surface wind associated with an axially-symmetric cyclonic vortex characterized by two parameters: the maximum tangential velocity and the radius at which that velocity is reached. The values of these two parameters, which depend on the position of the vortex, correspond to two cases: hurricane Hilda, which crossed the central part of the Gulf of Mexico between September 29 and October 3, 1964 and hurricane Gilbert whose trajectory between 11 and 17 September, 1988 crossed the Caribbean Sea, the Yucatan Peninsula and the southwest Gulf of Mexico. The results show that a cyclonic vortex with such characteristics, produce during its passage by the sea vertical turbulent water transport through the thermocline (entrainment) that is able to cool down the mixed layer in several degrees and increases the thermocline depth in several meters, in agreement with the observations. [Spanish] Se aplica un modelo de capa de mezcla para el Golfo de Mexico con el objeto de determinar el efecto de un vortice ciclonico idealizado sobre la temperatura de la superficie del mar. El modelo consiste basicamente de dos ecuaciones, la de conservacion de energia termica y la de balance entre energia mecanica y energia termica, esta ultima derivada de la teoria de Kraus-Turner; ambas ecuaciones son verticalmente integradas y acopladas en la capa de mezcla. Como forzamiento atmosferico sobre la superficie del mar se prescribe el viento asociado a un vortice ciclonico axialmente simetrico caracterizado por dos parametros: la velocidad tangencial maxima y el radio al

  8. Micrometeorological studies for the characterization of the atmospheric superficial layer in the Valley of Mexico; Estudios micrometeorologicos para la caracterizacion de la capa atmosferica superficial en el Valle de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Saldana Flores, Ricardo; Salcido Gonzalez, Victor A.; Borja Diaz, Marco Antonio R.; Morales Reyes, Maria Flor [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1995-12-31

    This work establishes the principal aspects related to two micrometeorological campaigns carried out in the Valley of Mexico, the first one from May 19 to 27, 1992 in the vicinity of the Valle de Mexico thermoelectric central and the second from September 13 to 21, 1993 in a site nearby the recreational lake of the Texcoco Plan. The first campaign of measurements encompassed the monitoring at ground level (at a height of 10 meters) of the following parameters: -wind orthogonal components; -temperature; -relative humidity; -Global radiation; - Net radiation; -Atmospheric pressure. Also, simultaneously five daily radio soundings were performed through a captive balloon and free soundings, up to an approximate height of 2500 meters. During the second campaign the same measurements as in the first campaign were carried out, except the radio soundings with the captive balloon, incorporating a turbulence ultrasonic sensor with which, among other parameters, were obtained: -Mean velocities of the wind orthogonal components; -Mean temperature; -Covariance of the wind component z and temperature; -Friction velocity; -Monin-Obukov length; -Vertical heat flow; -Wind mean velocity; -Wind mean direction. [Espanol] En el presente trabajo se anotan los principales aspectos relativos a dos campanas micrometeorologicas realizadas en el Valle de Mexico, la primera del 19 al 27 de mayo de 1992 en las inmediaciones de la central termoelectrica Valle de Mexico y la segunda del 13 al 21 de septiembre de 1993, en un sitio cercano al lago recreativo del Plan Texcoco. La primera campana de mediciones abarco el monitoreo en superficie (a 10 m de altura) de los siguientes parametros: - Componentes ortogonales del viento. - Temperatura. - Humedad relativa. - Radiacion global. - Radiacion neta. - Presion atmosferica. Asimismo, se llevaron a cabo simultaneamente cinco radiosondeos diarios a traves de un globo cautivo y de sondas libres, hasta una altura aproximada de 2500 metros. Durante la

  9. Parameter sensitivity of high-order equivalent circuit models of turbine generator; Sensibilidad parametrica de modelos de circuitos equivalentes de orden superior de turbogeneradores

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Garcia, I.; Escalera Perez, R. [Universidad Autonoma Metropolitana - Azcapotzalco (Mexico)]. E-mail: irvinlopez@yahoo.com; r.escalera@ieee.org; Niewierowicz Swiecicka, T. [Instituto Politecnico Nacional, U.P. Adolfo Lopez Mateos (Mexico)]. E-mail: tniewi@ipn.mx; Campero Littlewood, E.[Universidad Autonoma Metropolitana - Azcapotzalco (Mexico)]. E-mail: ecl@correo.azc.uam.mx

    2010-01-15

    This work shows the results of a parametric sensitivity analysis applied to a state-space representation of high-order two-axis equivalent circuits (Ecs) of a turbo generator (150 MVA, 120 MW, 13.8 kV y 50 Hz). The main purpose of this study is to evaluate each parameter impact on the transient response of the analyzed two axis models -d axis Ecs with one to five damper branches and q axis Ecs from one to four damper branches-. The parametric sensitivity concept is formulated in a general context and the sensibility function is established from the generator response to a short circuit condition. Results ponder the importance played by each parameter in the model behavior. The algorithms were design within MATLAB environment. The study gives way to conclusion on electromagnetic aspects of solid rotor synchronous generators that have not been previously studied. The methodology presented here can be applied to any other physical system. [Spanish] En este trabajo se presentan los resultados del analisis de sensibilidad parametrica realizado a modelos de circuitos equivalentes de orden superior de un turbogenerador (150 MVA, 120 MW, 13.8 kV y 50 Hz). La representacion del generador sincrono se hace en el espacio de estados, utilizando la teoria de dos ejes (d y a). El objetivo del estudio de sensibilidad es evaluar el impacto que tiene cada uno de los parametros en la respuesta transitoria de los modelos analizados -circuitos equivalentes desde una hasta cinco ramas de amortiguamiento en el eje d y de una a cuatro ramas en el eje q-. En este trabajo el concepto de sensibilidad parametrica se formula en terminos generales, planteando la funcion de sensibilidad a partir de condiciones de cortocircuito en las terminales del generador. Los resultados se presentan senalando el nivel de importancia de cada parametro en el comportamiento del modelo. Los algoritmos utilizados fueron disenados en MATLAB. Asi, este estudio permite inferir aspectos electromagneticos de los

  10. The effect of oxidation time on the parameters of ITO/Si solar cell prepared by spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Kandil, S. A; Afifi, H. H; El-hefnawi, S. H; Eliwa, A.Y [Electronic Research Institute, Dokki, Cairo (Egypt)

    2000-07-01

    The indium tin oxide (ITO/N-Si) solar cells have been fabricated by spray pyrolysis technique. The silicon wafers are heated at 500 Celsius degrees with different oxidation time (2-20 min). The best values obtained for ITO/Si solar cell output parameters; open circuit voltage V{sub o}c, short circuit current density J{sub s}c, fill factor FF and efficiency {eta} are 0.48 V, 15 mA/cm{sup 2}, 0.7 and 10.1% respectively. The preceding results were obtained under conditions of 5 minutes oxidation time and the surface area equal to 8 mm{sup 2} when the light intensity is 50 MW/ cm{sup 2}. The values of V{sub o}c, J{sub s}c, FF and {eta} are affected strongly by the varying the oxidation time. This paper is devoted to explain the effect of the interfacial layer SiO{sub 2} thickness on the ITO/Si solar cell parameters as deduced from the I-V and C-V measurements. [Spanish] Mediante tecnicas de pirolisis de dispersion se han fabricado celdas solares de oxido de Indio estanado ITO/N-Si. Las obleas de silicon se calientan a 500 con diferentes tiempos de oxidacion (2-20 min.) Los mejores valores obtenidos para los parametros de produccion de las celdas solares ITO-Si de voltaje en circuito abierto V{sub o}c densidad de corriente de corto circuito J{sub s}c factor de llenado FF y eficiencia {eta} son de 0.48 V, 15 mA/cm{sup 2}, 0.7% y 10.1% respectivamente los resultados precedentes se obtuvieron bajo condiciones de 5 minutos de tiempo de oxidacion y la superficie del area=8 mm{sup 2} cuando la intensidad de la luz es de 50mW/Cm{sup 2}. Los valores de V{sub o}c, J{sub s}c, FF y {eta} se afectan fuertemente por la variacion del tiempo de oxidacion. Este articulo esta dedicado a explicar el efecto del espesor de la capa interfacial de SiO{sub 2} en los parametros de la celda solar ITO-Si como se deduce de las mediciones I-V y C-V.

  11. A theory of phase separation in asphaltene-micellar solutions

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco Sanchez, Juan H. [Instituto Mexicano del Petroleo, Mexico D.F. (Mexico)

    2001-08-01

    teorico. Algunos resultados muestran el diagrama de fase de temperatura contra concentracion de asfaltenos. El diagrama de fase es examinado contra los escasos datos de concentracion critica de micelas de asfalteno en tolueno. Ademas tambien es cualitativamente examinado contra diagrama de separacion de fase, relativamente nuevos, obtenidos experimentalmente. El crecimiento de las micelas asfaltenicas depende del parametro K, que es responsable de la forma y tamano de las mismas. A su vez, el parametro K depende tanto del numero de asfaltenos monomericos asociados en las micelas asfaltenicas, como de los potenciales quimicos en el interior y periferia de la micela. Se obtuvo una expresion para conseguir el numero de asfaltenos monomericos autoasociados en la micela asfaltenica.

  12. Micrometeorological studies for the characterization of the atmospheric superficial layer in the Valley of Mexico; Estudios micrometeorologicos para la caracterizacion de la capa atmosferica superficial en el Valle de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Saldana Flores, Ricardo; Salcido Gonzalez, Victor A; Borja Diaz, Marco Antonio R.; Morales Reyes, Maria Flor [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    This work establishes the principal aspects related to two micrometeorological campaigns carried out in the Valley of Mexico, the first one from May 19 to 27, 1992 in the vicinity of the Valle de Mexico thermoelectric central and the second from September 13 to 21, 1993 in a site nearby the recreational lake of the Texcoco Plan. The first campaign of measurements encompassed the monitoring at ground level (at a height of 10 meters) of the following parameters: -wind orthogonal components; -temperature; -relative humidity; -Global radiation; - Net radiation; -Atmospheric pressure. Also, simultaneously five daily radio soundings were performed through a captive balloon and free soundings, up to an approximate height of 2500 meters. During the second campaign the same measurements as in the first campaign were carried out, except the radio soundings with the captive balloon, incorporating a turbulence ultrasonic sensor with which, among other parameters, were obtained: -Mean velocities of the wind orthogonal components; -Mean temperature; -Covariance of the wind component z and temperature; -Friction velocity; -Monin-Obukov length; -Vertical heat flow; -Wind mean velocity; -Wind mean direction. [Espanol] En el presente trabajo se anotan los principales aspectos relativos a dos campanas micrometeorologicas realizadas en el Valle de Mexico, la primera del 19 al 27 de mayo de 1992 en las inmediaciones de la central termoelectrica Valle de Mexico y la segunda del 13 al 21 de septiembre de 1993, en un sitio cercano al lago recreativo del Plan Texcoco. La primera campana de mediciones abarco el monitoreo en superficie (a 10 m de altura) de los siguientes parametros: - Componentes ortogonales del viento. - Temperatura. - Humedad relativa. - Radiacion global. - Radiacion neta. - Presion atmosferica. Asimismo, se llevaron a cabo simultaneamente cinco radiosondeos diarios a traves de un globo cautivo y de sondas libres, hasta una altura aproximada de 2500 metros. Durante la

  13. Usual interstitial pneumonitis UIP presenting with Wells grade 3. Can imaging methods help predict further progression of disease?; Fibrosi polmanare idiopatica con grado 3 di Wells all'esordio: possono le metodiche di diagnostica per immagini aiutare a predire la progressione ulteriore della malattia?

    Energy Technology Data Exchange (ETDEWEB)

    Fasano, L.; Pacilli, A. M.G. [Bologna Policlinico, Bologna (Italy). Ist. di Fisiopatologia Respiratoria; Zompatori, M.; Monetti, N. [Bologna Policlinico, Bologna (Italy). Servizio di Medicina Nucleare; Battista, G. [Bologna Policlinico, Bologna (Italy). Ist. di Radiologia, Radiodiagnostica 1; Di Scioscio, V.; Sciascia, N.

    1999-10-01

    Three different grades of idiopathic pulmonary fibrosis can be identified by HRCT pattern. Patients with predominant ground-glass opacity (grade 1) usually improve after treatment and may have a better prognosis. The subjects with a predominant reticular pattern and honeycombing (grade 3.) have irreversible fibrosis and usually do not improve after immunosuppressive therapy. Nevertheless, these patients may worsen even in the absence of HRCT features of the so-called alveolitis. The aim of this report is to investigate the predictive role of some noninvasive imaging methods (HRCT with visual score of disease extent; Gallium scintigraphy; DTPA scintigraphy) in patients with idiopathic fibrosis and a prevalent macroscopic fibrosis at HRCT study. [Italian] La fibrosi polomare idiopatica viene distinta in 3 gradi con diversa prognosi in base alla predominanza di opacita' a vetro smerigliato da alveolite o di fibrosi irreversibile. La fibrosi irreversibile tuttavia non e' necessariamente una situazione stabile ma puo progredire ed evolvere ulteriormente. In particolare i pazienti che gia all'esordio presentano solo i segni della fibrosi possono peggiorare a distanza di tempo nonostante la terapia. Scopo del lavoro e' stato quello di individuare in un gruppo di pazienti con prevalente fibrosi macroscopica quale possa essere un parametro preditivo della successiva evoluzione della malattia.

  14. Effects of increasing soil acidity and decreasing nutrient availability on the growth of Vochysiafe""ginea a secondary rain forest of Northern Costa Rica

    Directory of Open Access Journals (Sweden)

    Bernal Herrera

    2001-01-01

    Full Text Available Efecto del aumento en la acidez del sue- 10 y la disminucion en la disponibilidad de nu- trimentos sobre el crecimiento de Vochysiafe- rruginea en el bosque humedo de la region Norte de Costa Rica. En el presente trabajo se compara el crecimiento de la especie ~ ferrugi- varianea en 3 sitios del bosque humedo secundario de edad avanzada, ubicados en la zona norte de Costa Rica, bajo condiciones crecientes de aci- dez y de menor disponibilidad de nutrimentos en parael suelo. Se instalaron un total de 28 parcelas temporales de muestreo (20x20m, de tal forma que cubrieran toda la variacion del sustrato pre- sente en los sitios de estudio. Como parametros indicadores de la capacidad productiva del sitio bese utilizaron la altura esperada de un arbol a los 25 cm de dap (estimada en una investigacion condiprevia, el area basaVha y la altura total. Las comparaciones estadfsticas (P<0.05 mostraron diferencias significativas en cuanto a la produc- tividad de los sitios. Los sitios con mayor pro- ductividad presentaron el menor grado de pen- indiente, el mayor porcentaje de saturaci6n de AI, los mayores contenidos de Fe y P, asf como las menores concentraciones de bases intercambia-

  15. An application of neural network in geophysical prospecting. Electrical resistivity at Las Virgenes geothermal field, Baja California Sur, Mexico; Una aplicacion de las redes neuronales a la prospeccion geofisica. Resistividad electrica en las Tres Virgenes, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Palma Guzman, Sergio Hugo [Comision Federal de Electricidad, Morelia, Michoacan (Mexico)

    2000-12-01

    The technology of the neural network is presented with geophysical focus in the Las Virgenes geothermal field, Baja California Sur, Mexico. The results obtained when extrapolating the associative data of the prospecting magnetoteluria and Vertical Electric Sounding, on the area of the geothermal wells to the rest of the area, allows to classify zones of interest for the geothermal exploitation. Also, the use of these associative parameters with the information of the stabilized temperature of the wells, they allow to predict temperatures for the rest of the area. [Spanish] Se presenta una aplicacion de la tecnologia de las redes neuronales con enfoque geofisico en el campo geotermico de Las Virgenes, Baja California Sur, Mexico. Los resultados obtenidos al extrapolar los datos asociativos de las prospecciones geoelectricas de magnetoteluria y sondeos electricos verticales, en la zona de los pozos geotermicos al resto del area, permiten clasificar zonas de interes para la explotacion geotermica. Tambien, la utilizacion de estos parametros asociativos con la informacion de la temperatura estabilizada de los pozos, permiten predecir temperaturas para la misma area.

  16. Efecto de colutorio-gel de clorhexidina sobre el crecimiento de placa en 24 horas = Effect of chlorhexidine mouthrinses-gel on de novo plaque formation in 24 hours

    Directory of Open Access Journals (Sweden)

    Rivera, Tânia

    2006-01-01

    Full Text Available En un estudio cruzado, doble ciego y randomizado, 25 alumnos de Odontologia de buena salud oral, participaron de cuatro estudios donde ellos se abtuvieron de toda limpieza mecanica oral por 24 horas, los estudios estuvieron separados entre si por 4 semanas. Durante los estudios los alumnos en un randomizado orden, se enjuagaron por una vez con uno de los siguientes colutorios: CHX 0.12% + alcohol (Oralgene®, CHX 0.12% + alcohol (Perio.Aid®, CHX 0.1% + alcohol (Dentilim® y CHX 0.1% + HMC 2.5% (Colutoriogel®, nueva formula. Despues de un dia se midio formación de placa, se completo y registro el cuestionario de parametros clinicos. Las formulaciones de CHX 0.12% + alcohol y CHX 0.1% + HMC 2.5% se mostraron eficientes en retardar el crecimiento de placa dental de novo, esto obtenido de las observaciones clinicas, y siempre superior (p < 0.05 a la formulación del colutorio de CHX 0.1%+ alcohol (Dentilim®. Los resultados de este estudio demuestran el potencial clinico de este nuevo colutorio-gel sin alcohol de CHX 0.1% + HMC 2.5% (Colutoriogel® como un efectivo agente antiplaca y con reducidas efectos secundarios registrados

  17. Hydraulic speed variators for electrical energy saving; Variadores de velocidad hidraulicos para el ahorro de energia electrica

    Energy Technology Data Exchange (ETDEWEB)

    Valera Negrete, Adrian [Programa de Ahorro de Energia del Sector Electrico (PAESE), Mexico, D. F. (Mexico)

    1999-07-01

    This paper shows the characteristics and applications of the hydraulic speed variators, where because of the conditions of the industrial processes it is necessary to vary the operation parameters, obtaining therefore an energy saving besides improving the control of these processes. In addition, the technical and economic evaluation is presented of a project of the Mazatlan Fossil Power Plant, in which it is intended to invest in the installation of a hydraulic speed variator connected to the forced draft fan of unit number three, which operates with an induction motor of 1,865 kW (2,500 H.P.), with a Voltage of 4,180 V at 1,180 rpm. [Spanish] El presente trabajo muestra las caracteristicas y aplicaciones de los variadores de velocidad hidraulicos, donde por las condiciones de los procesos industriales sea necesario variar los parametros de operacion, obteniendose asi un ahorro de energia ademas de mejorar el control de dichos procesos. Se presenta ademas la evaluacion tecnica y economica de un proyecto de la Planta Termoelectrica Mazatlan, en donde se pretende invertir en la instalacion de un variador de velocidad hidraulico acoplado al ventilador de tiro forzado de la unidad numero tres, el cual opera con un motor de induccion de 1,865 kW (2,500 H.P.), con un voltaje de 4,180 V y una velocidad de 1,180 rpm.

  18. Regional Analysis of Precipitation by Means of Bivariate Distribution Adjusted by Maximum Entropy; Analisis regional de precipitacion con base en una distribucion bivariada ajustada por maxima entropia

    Energy Technology Data Exchange (ETDEWEB)

    Escalante Sandoval, Carlos A.; Dominguez Esquivel, Jose Y. [Universidad Nacional Autonoma de Mexico (Mexico)

    2001-09-01

    The principle of maximum entropy (POME) is used to derive an alternative method of parameter estimation for the bivariate Gumbel distribution. A simple algorithm for this parameter estimation technique is presented. This method is applied to analyze the precipitation in a region of Mexico. Design events are compered with those obtained by the maximum likelihood procedure. According to the results, the proposed technique is a suitable option to be considered when performing frequency analysis of precipitation with small samples. [Spanish] El principio de maxima entropia, conocido como POME, es utilizado para derivar un procedimiento alternativo de estimacion de parametros de la distribucion bivariada de valores extremos con marginales Gumbel. El modelo se aplica al analisis de la precipitacion maxima en 24 horas en una region de Mexico y los eventos de diseno obtenidos son comparados con los proporcionados por la tecnica de maxima verosimilitud. De acuerdo con los resultados obtenidos, se concluye que la tecnica propuesta representa una buena opcion, sobre todo para el caso de muestras pequenas.

  19. Technological evolution of the fluorescent lamps for the domestic sector; Evolucion tecnologica de lamparas fluorescentes para el sector domestico

    Energy Technology Data Exchange (ETDEWEB)

    Valera Negrete, A. [Programa de Ahorro de Energia para el Sector Electrico, Mexico, D. F. (Mexico)

    1995-12-31

    This paper shows the efficiency, the harmonic distortion and the power factor of compact and circular fluorescent lamps that replace the incandescent bulbs of 60, 75 and 100 Watts in the domestic sector offered by manufacturers to increase the efficient use of the electric energy in networks of the national electric system. Also are presented, the quality parameters such as color temperature, performance index, useful life and maintenance of the lighting source; the aesthetics as length and weight and additionally the safety measures (thermal protector) that make competitive and functional the use of fluorescent lamps in relation to the installation of incandescent bulbs. [Espanol] En este trabajo se muestran las eficacias, distorsion de armonica y factor de potencia de lamparas fluorescentes compactas y circulares, que sustituyen a focos incandescentes de 60, 75 y 100 W en el sector domestico, ofrecidas por los fabricantes para aumentar el uso eficiente de la energia electrica en las redes del sistema electrico nacional. Ademas, se presentan los parametros de calidad, como temperatura de color, indice de rendimiento de color, vida y mantenimiento de la fuente luminosa; de estetica como longitud y peso; y adicionalmente la medida de seguridad (protector termico); que hace competitivo y funcional el uso de lamparas fluorescentes respecto a la instalacion de focos incandescentes.

  20. Test de Actitudes Alimentarias: Evidencias de Validez de una Nueva Versión Reducida

    Directory of Open Access Journals (Sweden)

    Valdiney Veloso Gouveia

    2010-01-01

    Full Text Available El objetivo de este estudio ha sido presentar una version reducida del Eating Attitudes Test (EAT-26 para su utilizacion en el contexto espanol. Se busco especificamente conocer su fiabilidad y estructura factorial para, finalmente, comprobar el modelo teorico propuesto. Para ello, contamos con una muestra de 212 estudiantes universitarios con una edad media de 19.4 anos, la mayoria mujeres (61.8%. Estos respondieron al EAT-26 y a preguntas sociodemograficas. Inicialmente, a traves de un analisis paralelo se observo la coherencia de la estructura factorial. A continuacion se seleccionaron, a partir del poder discriminativo (p < 0.05, cuatro items para cada factor. Mediante el analisis de Escalamiento Multidimensional, se observo que los 12 items resultantes se distribuian segun las dimensiones teoricas esperadas (S-Stress = 0.07; RSQ = 0.97, aspecto corroborado a traves del analisis factorial confirmatorio (x2 / g.l = 2.08; GFI = 0.92; AGFI = 0.88; CFI = 0.94; e RMSEA = 0.071. Los Alfas de Cronbach para los tres factores pueden ser considerados satisfactorios: Hacer dieta (0.87, Bulimia y preocupacion por la alimentacion (0.60 y Control oral (0.52. Se concluye que la version propuesta presenta parametros psicometricos satisfactorios, pudiendo ser utilizada como medida de screening en la deteccion precoz de casos de anorexia nerviosa en la poblacion general.

  1. Technological evolution of the fluorescent lamps for the domestic sector; Evolucion tecnologica de lamparas fluorescentes para el sector domestico

    Energy Technology Data Exchange (ETDEWEB)

    Valera Negrete, A [Programa de Ahorro de Energia para el Sector Electrico, Mexico, D. F. (Mexico)

    1996-12-31

    This paper shows the efficiency, the harmonic distortion and the power factor of compact and circular fluorescent lamps that replace the incandescent bulbs of 60, 75 and 100 Watts in the domestic sector offered by manufacturers to increase the efficient use of the electric energy in networks of the national electric system. Also are presented, the quality parameters such as color temperature, performance index, useful life and maintenance of the lighting source; the aesthetics as length and weight and additionally the safety measures (thermal protector) that make competitive and functional the use of fluorescent lamps in relation to the installation of incandescent bulbs. [Espanol] En este trabajo se muestran las eficacias, distorsion de armonica y factor de potencia de lamparas fluorescentes compactas y circulares, que sustituyen a focos incandescentes de 60, 75 y 100 W en el sector domestico, ofrecidas por los fabricantes para aumentar el uso eficiente de la energia electrica en las redes del sistema electrico nacional. Ademas, se presentan los parametros de calidad, como temperatura de color, indice de rendimiento de color, vida y mantenimiento de la fuente luminosa; de estetica como longitud y peso; y adicionalmente la medida de seguridad (protector termico); que hace competitivo y funcional el uso de lamparas fluorescentes respecto a la instalacion de focos incandescentes.

  2. Technologies for the treatment of the sulfur dioxide and nitrogen oxides generated by the combustion in open chamber; Tecnologias para el tratamiento de dioxido de azufre y oxidos de nitrogeno generados por la combustion en camara abierta

    Energy Technology Data Exchange (ETDEWEB)

    Salazar Villalpando, Maria Dolores [Instituto Mexicano del Petroleo, Mexico, D. F. (Mexico)

    1993-12-31

    In general terms, there are only three ways of avoiding the sulfur dioxide and the nitrogen oxides, generated by the combustion in open chamber, from contaminating the air; the first one is utilizing low sulfur and nitrogen content fuels, the second one is by controlling the parameters that affect the combustion and the third one to treat and/or clean the gases before exhausting them to the air. In this document, some of the treatments for diminishing the pollutant emissions generated by the combustion in open chamber, are presented. [Espanol] En terminos generales, solo existen 3 maneras de evitar que el dioxido de azufre y oxidos de nitrogeno generados por la combustion en camara abierta sigan contaminando el aire, la primera es utilizar un combustible de bajo contenido de azufre y nitrogeno, la segunda es controlar los parametros que afectan la combustion, y la tercera es tratar y/o limpiar los gases antes de emitirlos a la atmosfera. En este documento se presentan algunos tratamientos para disminuir las emisiones de contaminantes generados por la combustion en camara abierta.

  3. Energy evaluation process of electric domestic refrigerators; Proceso de evaluacion energetica de refrigeradores electrodomesticos

    Energy Technology Data Exchange (ETDEWEB)

    Malacara Toral, Manuel; Ruiz Neblina, Joaquin [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1993-12-31

    A description is made of an energy evaluation study on electric domestic refrigerators carried out by the Instituto de Investigaciones Electricas (IIE), in its strategy for diminishing the energy consumption through the design enhancement, the manufacture, the operation and the standardization of the electric appliances. In order to initiate the evaluation-standardization process, the Mexican (NOM), the American (ANSI/AHAM) and the Canadian (CAN/CSA) standards were taken as a base to harmonize the procedures and the parameters of the tests. The energy assessment demonstrated that there are significant differences among the standards encompassed by the study, therefore, recommendations were made for the harmonization of the standards. [Espanol] Se describe un estudio de evaluacion energetica sobre refrigeradores electrodomesticos realizado en el Instituto de Investigaciones Electricas (IIE) dentro de la estrategia para disminuir los consumos de energia a traves de mejoras en el diseno, la manufactura, la operacion y la normalizacion de equipos electricos. Se tomo como base las normas mexicanas (NOM), americana (ANSI/AHAM) y canadiense (CAN/CSA) para iniciar el proceso de evaluacion-normalizacion a fin de armonizar los procedimientos y parametros de las pruebas. La evaluacion energetica demostro que existen diferencias significativas entre las normas que abarco el estudio por lo que se presentan recomendaciones para la armonizacion de las normas.

  4. Methodology for energy diagnosis in distribution steam lines; Metodologia para diagnostico de energia en lineas de distribucion de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Almanza, M; Ambriz, J J; Romero P, H [Universidad Autonoma Metropolitana Iztapalapa, Mexico, D. F. (Mexico)

    1993-12-31

    This paper shows a methodology that results of great advantage in the development of the energy analysis of an industrial facility that utilizes steam as a mean of energy transport and where the steam operated equipment is physically located in a remote place, away from the generation site. Mention is made here of the equipment characteristics that can be used for such purpose, the most important parameters to identify in a rapid and efficient way the faults presented in the steam distribution system in the industrial plants and the formats that contribute to keep the corresponding records for efficiently maintain in operation the steam pipeline net in conjunction with the involved accessories. [Espanol] En el presenta trabajo se muestra una metodologia que resulta de gran utilidad en el desarrollo del analisis energetico de una planta industrial, en la cual se emplee el vapor como medio de transporte de la energia y en donde el equipo que utiliza el vapor se encuentre fisicamente en un lugar apartado de la zona de generacion. Aqui se mencionan las caracteristicas del equipo que se puede utilizar para dicho diagnostico, los parametros de mayor importancia para identificar en forma rapida y eficiente las fallas que se presentan en el sistema de distribucion de vapor en las plantas industriales y los formatos que contribuyen a llevar los registros correspondientes para mantener operando eficientemente la red de vapor, en conjunto con los accesorios que en ella se involucran.

  5. ESFER computer tool for the evaluation of photovoltaic systems used in rural electrification; ESFER herramienta de computadora para evaluar sistemas fotovoltaicos utilizados en electrificacion rural

    Energy Technology Data Exchange (ETDEWEB)

    Villasenor, Francisco; Perez, Miguel; Huacuz, Jorge M [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    ESFER (Evaluacion de Sistemas Fotovoltaicos para Electrificacion Rural) Photovoltaic Systems Evaluation for Rural Electrification is a computerized calculation tool for the analysis of information and evaluation of photovoltaic systems for rural electrification. This article describes such a tool, as well as the parameters that are taken into account for analyzing the systems, the methodology to qualify and the computer program operation. The graphic results of a typical case are presented. ESFER pretends to be a program of general use for the evaluation of photovoltaic systems for rural electrification. [Espanol] ESFER, Evaluacion de Sistemas Fotovoltaicos para Electrificacion Rural, es una herramienta de calculo computarizada para el analisis de informacion y evaluacion de sistemas fotovoltaicos para electrificacion rural. En el presente articulo se describe dicha herramienta, asi como los parametros que se toman en cuenta para analizar los sistemas, la metodologia de calificacion y la operacion del programa de computadora. Se presentan los resultados graficos de un caso tipico. ESFER pretende ser un programa de uso generalizado para la evaluacion de sistemas fotovoltaicos de electrificacion rural.

  6. Ricerca del bosone di Higgs in produzione associata col bosone vettore W, nello stato finale $WH ->(\\mu\

    CERN Document Server

    Grippo, Maria Teresa

    Il Modello Standard (MS) è la teoria scientifica più dibattuta degli ultimi anni nel mondo della fisica delle alte energie. Essa racchiude i fondamenti della materia e descrive le interazioni che regolano l'universo. Il MS è stato confermato in numerosi esperimenti, quali LEP e Tevatron, ma presenta ancora un ultimo interrogativo relativo all'origine della massa delle particelle. Il MS cerca di spiegare ciò tramite il meccanismo di Higgs, proposto da Peter Higgs nel 1964 \\cite{Higgs}: viene introdotta una nuova particella, chiamata \\emph{bosone di Higgs}, che ha lo scopo tramite il suddetto meccanismo di fornire massa alle particelle. Di tale particella non si conosce la massa, che viene infatti assunta come parametro libero della teoria. Scopo di tale lavoro di tesi è stato quello di studiare presso l'esperimento CMS (\\emph{Compact Muon Solenoid}) a LHC (\\emph{Large Hadron Collider}) il canale di produzione associata WH, nell'intervallo di massa 115 GeV/$c^{2} \\leq m_H \\leq $ 135 GeV/$c^{2}$, negli stat...

  7. Bibliometric indicators: spread reflections for a focusing and conscious use

    Directory of Open Access Journals (Sweden)

    Tessa Piazzini

    2010-04-01

    Full Text Available Nel mondo scientifico e accademico l'uso di indicatori bibliometrici è ormai largamente diffuso ed è diventato un  parametro di giudizio per assegnare fondi di ricerca e valutare i risultati degli investimenti. Lo scopo di questo articolo è quello di fornire, senza alcuna pretesa di completezza, spunti di riflessione e consigli pratici per un utilizzo consapevole degli indicatori bibliometrici più consolidati, segnalandone i limiti e le peculiarità. Oltre al più noto e discusso indicatore bibliometrico, l'Impact factor, sono stati sviluppati negli ultimi anni alcuni sistemi alternativi legati all'open acess. Le più valide alternative sono rappresentate da Scimago, strumento gratuitamente consultabile on-line nato da un gruppo di ricerca del Consejo Superior de Investigaciones Científicas (CSIC in collaborazione con alcune università spagnole e Eigenfactor, progetto di ricerca accademica non-commerciale sponsorizzato dal Bergstrom lab dell’Università di Washington. Molto affermato è infine l'H-index (o Indice di Hirsch, messo a punto nel 2005 da Jorge E. Hirsch professore all’Università della California di San Diego. Questo recente indice cerca di ridimensionare alcuni eccessi del Citation index, equilibrando e rendendo compatibili autori molto prolifici, ma con un basso numero di citazioni per articolo e studiosi meno produttivi, ma con un alto rapporto citazione/articolo.

  8. Design and manufacture of an atmospheric burner of biogas with rural application; Diseno y construccion de un quemador atmosferico de biogas con aplicaciones rurales

    Energy Technology Data Exchange (ETDEWEB)

    Nunez Nunez, Jorge; Suarez Pacheco, Jose; Novelo Navarrete, Jose H; Soto Apolinar, Efrain [Universidad de Quintana Roo, Chetumal, Quintana Roo (Mexico)

    2000-07-01

    In this text it's resumed the methodology that was carried out to make an atmospheric burner of biogas, as the criteria that were taken in account in order to determine the main parameters of it. It introduces a synthesis of the stages of design and manufacture of the device. The utility of this type of burner increase the efficiency of the oxidation of the biogas compared with the use of conventional burners that aren't designed for this purpose. [Spanish] En este trabajo se resume la metodologia que se llevo a cabo para la construccion de un quemador de biogas tipo atmosferico, asi como los criterios que se tomaron para la determinacion de los parametros principales del mismo. Se presenta una sintesis de las etapas de diseno y manufactura del dispositivo. El uso de este tipo de quemadores aumenta la eficiencia de la oxidacion del biogas en comparacion con el uso de quemadores convencionales que no estan disenados para quemar biogas.

  9. DESARROLLO DE APIO MINIMAMENTE PROCESADO FORTIFICADO CON VITAMINA E, UTILIZANDO LA INGENIERIA DE MATRICES

    Directory of Open Access Journals (Sweden)

    YISELL JOHAN MARTELO CASTAÑO

    2011-01-01

    Full Text Available El objetivo de este trabajo fue desarrollar un producto minimamente procesado fortificado con vitamina E, a partir de apio (Apium graveolens L. var.dulce, utilizando la ingenieria de matrices como metodologia de obtencion de alimentos funcionales. Trozos de apio impregnados al vacio con dl¿¿tocoferol acetato emulsificado en una solucion isotonica al vegetal de NaCl, 1,2%, fueron evaluados en funcion del tiempo de almacenamiento y el envasado (con y sin vacio, en terminos de la cuantificacion de sus propiedades fisicoquimicas, color, textura, estabilidad de la vitamina E y caracteristicas sensoriales. Se formulo la emulsion con el objetivo de adicionar teoricamente un 73% del Valor Diario Recomendado (VDR vitamina E/100 g de apio fresco y su cuantificacion se realizo por HPLC. La respuesta a la impregnacion en la matriz fue de 12,10+-1,15%, lo cual permitio alcanzar un 112% VDR vitamina E/100g apio fresco, manteniendose este contenido durante el almacenamiento de 9 dias en ambos tipos de envasado. Los parametros fisicoquimicos del producto fueron afectados por la IV, el tiempo y el envasado, manteniendo su coloracion verdosa y presentando disminucion en la firmeza. La ingenieria de matrices constituye una metodologia efectiva para el desarrollo de apio minimamente procesado adicionado con vitamina E.

  10. Quistes de los maxilares

    Directory of Open Access Journals (Sweden)

    Ivan Alberto Manotas Arevalo

    2013-12-01

    Full Text Available Los Grandes Quistes de los Maxilares han estado vinculados siempre a la humanidad, desde tiempos remotos, pues han sido halladas en restos de especimenes fosiles, han llamado la atencion de los clínicos, en torno a su etiologia, en la que se ha introducido la participacion de la genetica, (demostrada en el desarrollo de los queratoquistes maxilares, la fisiopatologia, caracteristicas histologicas (inmunohistoquimica, posibilidades diagnosticas por la imagen, (como la tomografia computarizada y la resonancia nuclear magnetica y otras pruebas. Además llaman la atención al estudio, por sus alternativas de manejo especialmente las formas radicales, y el analisis de asociaciones a otras patolo-gias benignas y malignas, y de la recurrencia muy alto de algunas de estas lesiones. Mucho se ha desarrollado para elucidar su naturaleza real, estadificar adecuadamente la lesion descartando asocia-ciones patologicas sindromicas, indicar un tratamiento apropiado, y realizar seguimientos a largo plazo. Este articulo pretende recaudar una information general que de parametros para abordar el estudio de los quistes maxilares a partir de la presentacion de un caso clinico.

  11. Bases para la elaboracion de unidades didacticas de calidad en el area de ciencias (Fisica y Quimica 3 deg ESO)

    Science.gov (United States)

    Maccioni, Elena Lucia

    Este Trabajo Fin de Master tiene como objeto, el estudio previo de la educacion de la ciencia en la actualidad y mas destacable, del diseno de las unidades didacticas segun las metodologias mas frecuentes aplicadas por los diferentes sistemas educativos en el area de las Ciencias teniendo en cuenta la importancia y el efecto de la psicologia del alumnado y todo ello como no puede ser de otro modo bajo el corse de la Legislacion aplicable, Estatal, Autonomica y europea. Con estos antecedentes, se extrae cuales son las preguntas que deben contestarse en la elaboracion de una unidad didactica de calidad en el contexto, generacional (edad y sexo), del Proyecto Educativo de Centro, y de la Programacion del Departamento, discutiendo y justificando cada uno de los apartados en que estructuradamente dividiremos dicha Unidad, con un formato manejable, util, y dinamico en el tiempo que sea un verdadero instrumento educativo de aula. Teniendo en cuenta estas premisas, se procede a hacer una recopilacion de una misma unidad didactica publicada por diferentes editoriales, elegidas no al azar, sino en funcion de su penetracion editorial en nuestros centros de ESO, siendo las elegidas (SM y Oxford). Las diferentes unidades seleccionadas son analizadas de forma critica, atendiendo a los criterios generales de calidad bajo parametros cientificos y normativos, concluyendo con la aportacion final que es la redaccion de unas pautas cientifico-pedagogicas, para redactar unidades didacticas de calidad en el area de la Ciencias, en concreto en la Asignatura de Fisica y Quimica de 3º de ESO.

  12. A SUSTENTABILIDADE EM FUNÇÃO DO USO NÃO SUSTENTÁVEL DOS RECURSOS NATURAIS NO OESTE BAIANO E EAGLE FORD TEXANO

    Directory of Open Access Journals (Sweden)

    Christian Brannstrom

    2015-01-01

    Full Text Available El artículo compara dos regiones con base en los discursos publicados em publicaciones bien diseminadas, complementada con investigación de campo. La región Oeste de Bahia, con agricultura intensive, compárase con el Eagle Ford Shale, región de producción no convencional de petroleo e gas natural. El trabajo focalízase en como las elites usan la sustentabilidad en la gobernanza ambiental para justificar el uso de los recursos naturales en la agricultura e los hidrocarbonos. Enfatizo como el espetáculo sirve para augmenter el “prestigio regional” (CHASE, 2003 e como los aspectos sociales de la sustentabilidad ajudan a consolidar las ambiciones de explotación de los recursos naturales. En los dos casos las elites regionals no reproducem verbatim los discursos nacionales, pero sí las elites investen en traduzir los discursos en formato regional o canalizar las preocupaciones regionales e los parametros regionales en nuevas soluciones discursivos para mantener la explotación de los recursos naturales.

  13. Development of a concept-based EMG-based speller

    Directory of Open Access Journals (Sweden)

    Robertas Damasevicius

    2015-01-01

    Full Text Available La computación fisiológica es un p aradigma de la computación qu e usa los datos de los usuarios como entradas durante las tarea s computacionales en un Ambiente de vidacotidianasoportado po rco mputadores (AAL. Monitoreando, an alizando y respondiendo a dic has entradas, los Sistemas de Computación Fisiológica pueden respon der al estado cognitivo, emocional y físico de los usuarios. Un caso particular es el de la interface de Computación Neuronal (NCI, que usa señales eléctricas para manejar la actividad muscular del usuario establecioendo una comunicación d irecta entre el usuario y el c omputador. Se present una taxonomía de parametros de aplicación de deletreo, proponiendo un modelo de PCS y describiendo el desarr ollo de un deletreador basado en EMG. Se analiza y desarrolla unaaplicación con un sistema basa do en letras tradicionales y u na interfaz visual. Finalmente, se evalua el desempeño y usabil idad del sistemadesarrollado.

  14. Models for power transformers monitoring in the intelligent electrical network: humidity and temperature of bubble generation; Modelos para el monitoreo de transformadores de potencia en la red electrica inteligente: humedad y temperatura de generacion de burbujas

    Energy Technology Data Exchange (ETDEWEB)

    Linan Garcia, Roberto; Ponce Noyola, David; Guzman Lopez, Arali [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Betancourt Ramirez, Enrique; Tamez Torres, Gerardo [PROLEC GE, (Mexico)

    2013-03-01

    This paper presents the development of two experimental models in order to ensure reliable operation of power transformers under emergency overload conditions. The first model estimates the moisture distribution in the transformer windings, while the second model estimates the safe operating temperature and time before steam bubbles generation presents. Additionally, an electronic device was designed and built, using the models developed, in order to monitor in real time both parameters. This device allows a more reliable operation of the transmission network, considering the transformers condition. [Spanish] Este documento presenta el desarrollo de dos modelos experimentales para asegurar la operacion confiable de transformadores de potencia bajo condiciones de sobrecarga de emergencia. El primer modelo estima la temperatura de operacion segura y el tiempo antes de que ocurra la generacion de burbujas de vapor. Ademas, se diseno y construyo un dispositivo electronico, usando los modelos desarrollados, con el fin de monitorear en tiempo real ambos parametros. Este dispositivo permite una operacion mas confiable de la red de transmision, considerando la condicion de los transformadores.

  15. Diafragmas horizontais de piso em madeira, confeccionados com chapas de OSB e vigas I, submetido ao carregamento vertical - DOI: 10.4025/actascitechnol.v29i2.579

    Directory of Open Access Journals (Sweden)

    Altevir Castro dos Santos

    2008-02-01

    Full Text Available Este trabalho aborda construções em madeira sob a ótica de sistemas com estruturas leves; apresenta an疝ise computacional por meio de modelagem pelo metodo de elementos finitos de diafragmas de piso e vigas I, submetidas a ensaio de flexão a quatro pontos. O objetivo geral é avaliar a resistência e a rigidez de diafragmas horizontais, construçõos em Sistemas Leves de Madeira, quando submetidos a ações verticais. As análises foram realizadas por meio do programa computacional SAP2000 e foram avaliadas as influencias dos seguintes parametros: espaçamento entre vigas que constituem os elementos de ossatura do diafragma horizontal e o espaçamento entre pregos de fixação do contrapiso, composto por chapas de OSB – Oriented Strand Board. Ao final do trabalho, comparam-se os resultados obtidos a partir das análises numérica e teórica, e são apresentadas algumas conclusões.

  16. Photoacoustic investigation of the effective diffusivity of two-layer semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Medina, J; Gurevich, Yu. G; Logvinov G, N; Rodriguez, P; Gonzalez de la Cruz, G. [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico)

    2001-08-01

    In this work, the problem of the effective thermal diffusivity of two-layer systems is investigated using the photoacoustic spectroscopy. The experimental results are examined in terms of the effective thermal parameters of the composite system determined from an homogeneous material which produces the same physical response under an external perturbation in the detector device. It is shown, that the effective thermal conductivity is not symmetric under exchange of the two layers of the composite; i.e., the effective thermal parameters depend upon which layer is illuminated in the photoacoustic experiments. Particular emphasis is given to the characterization of the interface thermal conductivity between the layer-system. [Spanish] En el presente trabajo se utiliza la espectroscopia fotoacustica para medir la difusividad termica de un sistema de dos capas. Los resultados experimentales son analizados en terminos de los parametros termicos efectivos determinados a partir de un material homogeneo, el cual produce la misma respuesta fisica bajo una perturbacion externa. Se puso particular enfasis en la caracterizacion de los efectos de interfase en el flujo de calor en el sistema de dos capas. Los resultados experimentales se comparan con el modelo teorico propuesto en este trabajo.

  17. Methodology for monitoring the behaviour of wind-photovoltaic hybrid system in the conditions of Cuba; Metodologia para el monitoreo del comportamiento de un sistema hibrido eolico-fotovoltaico en las condiciones de Cuba

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez G, Maria; Nunez, Ariel; Marquez M, Soe del C [Centro de Investigaciones de Energia Solar, Santiago de Cuba (Cuba)

    2000-07-01

    The proposal of a methodology is shown in the work that allows monitoring the behaviour of wind-photovoltaic hybrid system beginning with the study of the energy resources (wind and solar) of the known place, designed and put into operation a hybrid installation, using Text Processing techniques could obtained operation curves of the system daily, monthly and annual, to configure the reading for port series of the parameters measured during the evaluation of the system a denominated software HYBSYS was developed in Lab View for Windows 3.1 or superior. [Spanish] Se muestra la propuesta de una metodologia que permite monitorear el comportamiento de un sistema hibrido eolico-fotovoltaico, comenzando con el estudio de los recursos energeticos (eolico y solar) de un sitio conocido se diseno y puso en funcionamiento una instalacion hibrida, usando las tecnicas de un procesador se pudieron obtener las curvas de funcionamiento diaria, mensual y anual del sistema, para configurar la lectura por puerto serie de los parametros medidos durante la evaluacion del sistema se desarrollo un software denominado HYBSYS en Lab View para Windows 3.1 o superior.

  18. Multiple sclerosis test or the 4 humors: cerebrospinal fluid serum, tears and saliva; Esclerosis multiple test de los 4 humores: liquido cefalorraquideo, suero, lagrimas y saliva

    Energy Technology Data Exchange (ETDEWEB)

    Oehninger Gatti, C; Buzo Del Puerto, R; Chouza Antelo, C; Scotti Bianchi, C; Cibils, D; Alcantara Pelaez, J; Gomez, A; Heuguerot Oliveira, C

    1994-12-15

    4 were studied biological fluids easily accessible to the immune exploration (cerebrospinal fluid, serum, tears and saliva) in 25 patients with Multiple Sclerosis (MS) during a push clinical disease. The level of interleukin-2 receptor soluble (RsIL-2) was significantly increased by at least 3 of these 4 fluids, compared with normal controls. The sensitivity and specificity of its determination for the diagnosis of the condition was higher than other immunochemical parameters, oligoclonal distribution (OD) of immunoglobulin (Ig) light chain imbalance-and-evoked electrophysiological studies. This method is used to establish a more accurate diagnosis of Multiple Sclerosis as well as to monitor its biological activity with nuclear magnetic resonance (NMR) (Author) [Spanish] Se estudiaron 4 fluidos biologicos de facil acceso a la exploracion inmune (liquido cefalorraquideo, suero, lagrimas y saliva) en 25 pacientes con Esclerosis Multiple (EM) obtenidos durante un empuje clinico de la enfermedad. El nivel del receptor de Interleukina-2 soluble (RsIL-2) se encontro significativamente aumentado en por lo menos 3 de estos 4 fluidos, en comparacion con el de los controles normales. La sensibilidad y especificidad de su determinacion para el diagnostico de la afeccion, fue mayor que la de otros parametros inmunoquimicos - distribucion oligoclonal (DO) de inmunoglobulinas (Ig), disbalance de cadenas livianas - y estudios electrofisiologicos -potenciales evocados-. Este metodo es utilizado para establecer un diagnostico mas certero de la Esclerosis Multiple asi como tambien para monitorizar su actividad biologica junto con la resonancia magnetica nuclear (RMN)(Author)

  19. Study for obtaining a suppressor device of transients using the Al/SRO/Si structure; Estudio para la obtencion de un dispositivo supresor de transitorios utilizando la estructura Al/SRO/Si

    Energy Technology Data Exchange (ETDEWEB)

    Marin Ramos, Heriberto

    1999-06-01

    transitorios de voltaje. En este trabajo se presenta la estructura Aluminio/Oxido rico en Silicio/Silicio como otra opcion en el campo de los dispositivos supresores de transitorios. Algunos dispositivos utilizados en la supresion de transitorios de voltaje son: varistores de oxido de zinc, varistores de carburo de silicio, celdas de selenio, diodos zener, etcetera. La estructura AI/SRO/Si presenta propiedades conductoras debido a la presencia de exceso de silicio en la pelicula de SRO. Variando la razon de gases reaccionantes (Ro=N{sub 2}O/SiH{sub 4}) durante el crecimiento de la pelicula de Oxido Rico en Silicio (SRO, por sus siglas en ingles), se puede variar la conductividad del material. El SRO resulta de mucha importancia para el dispositivo supresor de transitorios que se pretende obtener en el presente trabajo debido a su comportamiento no-ohmico. El dispositivo AI/SRO/Si se comporta de varias maneras dependiendo de las caracteristicas del SRO y del sustrato de silicio. Se ha encontrado que uno de estos comportamientos es como un supresor de transitorios de voltaje. Verificando su comportamiento como supresor de transitorios, se estudiaron los efectos del espesor de la pelicula, del area y del exceso de silicio del dispositivo, para lo cual se obtuvo la caracteristica I-V, y la obtencion de algunos parametros en c.d. En el presente trabajo el SRO se obtuvo mediante LPCVD (Low Pressure Chemical Vapor Deposition), inicialmente se realizo una caracterizacion C-V para obtener parametros indicativos del exceso de silicio, tales como: permitividad de la pelicula de SRO. Tambien se obtuvo el indice de refraccion, el cual es un parametro indicativo de la presencia de exceso de silicio. Una vez teniendo la certeza de la presencia de exceso de silicio se procedio a obtener la caracteristica I-V de la estructura AI/SRO/Si como dispositivo. Se analizo el comportamiento de la estructura AI/SRO/Si con diferentes parametros, tales como: Ro, espesor de SOR, areas.

  20. Energy evaluation process of electric domestic refrigerators; Proceso de evaluacion energetica de refrigeradores electrodomesticos

    Energy Technology Data Exchange (ETDEWEB)

    Malacara Toral, Manuel; Ruiz Neblina, Joaquin [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1992-12-31

    A description is made of an energy evaluation study on electric domestic refrigerators carried out by the Instituto de Investigaciones Electricas (IIE), in its strategy for diminishing the energy consumption through the design enhancement, the manufacture, the operation and the standardization of the electric appliances. In order to initiate the evaluation-standardization process, the Mexican (NOM), the American (ANSI/AHAM) and the Canadian (CAN/CSA) standards were taken as a base to harmonize the procedures and the parameters of the tests. The energy assessment demonstrated that there are significant differences among the standards encompassed by the study, therefore, recommendations were made for the harmonization of the standards. [Espanol] Se describe un estudio de evaluacion energetica sobre refrigeradores electrodomesticos realizado en el Instituto de Investigaciones Electricas (IIE) dentro de la estrategia para disminuir los consumos de energia a traves de mejoras en el diseno, la manufactura, la operacion y la normalizacion de equipos electricos. Se tomo como base las normas mexicanas (NOM), americana (ANSI/AHAM) y canadiense (CAN/CSA) para iniciar el proceso de evaluacion-normalizacion a fin de armonizar los procedimientos y parametros de las pruebas. La evaluacion energetica demostro que existen diferencias significativas entre las normas que abarco el estudio por lo que se presentan recomendaciones para la armonizacion de las normas.

  1. Methodology for energy diagnosis in distribution steam lines; Metodologia para diagnostico de energia en lineas de distribucion de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Almanza, M.; Ambriz, J. J.; Romero P, H. [Universidad Autonoma Metropolitana Iztapalapa, Mexico, D. F. (Mexico)

    1992-12-31

    This paper shows a methodology that results of great advantage in the development of the energy analysis of an industrial facility that utilizes steam as a mean of energy transport and where the steam operated equipment is physically located in a remote place, away from the generation site. Mention is made here of the equipment characteristics that can be used for such purpose, the most important parameters to identify in a rapid and efficient way the faults presented in the steam distribution system in the industrial plants and the formats that contribute to keep the corresponding records for efficiently maintain in operation the steam pipeline net in conjunction with the involved accessories. [Espanol] En el presenta trabajo se muestra una metodologia que resulta de gran utilidad en el desarrollo del analisis energetico de una planta industrial, en la cual se emplee el vapor como medio de transporte de la energia y en donde el equipo que utiliza el vapor se encuentre fisicamente en un lugar apartado de la zona de generacion. Aqui se mencionan las caracteristicas del equipo que se puede utilizar para dicho diagnostico, los parametros de mayor importancia para identificar en forma rapida y eficiente las fallas que se presentan en el sistema de distribucion de vapor en las plantas industriales y los formatos que contribuyen a llevar los registros correspondientes para mantener operando eficientemente la red de vapor, en conjunto con los accesorios que en ella se involucran.

  2. Technologies for the treatment of the sulfur dioxide and nitrogen oxides generated by the combustion in open chamber; Tecnologias para el tratamiento de dioxido de azufre y oxidos de nitrogeno generados por la combustion en camara abierta

    Energy Technology Data Exchange (ETDEWEB)

    Salazar Villalpando, Maria Dolores [Instituto Mexicano del Petroleo, Mexico, D. F. (Mexico)

    1992-12-31

    In general terms, there are only three ways of avoiding the sulfur dioxide and the nitrogen oxides, generated by the combustion in open chamber, from contaminating the air; the first one is utilizing low sulfur and nitrogen content fuels, the second one is by controlling the parameters that affect the combustion and the third one to treat and/or clean the gases before exhausting them to the air. In this document, some of the treatments for diminishing the pollutant emissions generated by the combustion in open chamber, are presented. [Espanol] En terminos generales, solo existen 3 maneras de evitar que el dioxido de azufre y oxidos de nitrogeno generados por la combustion en camara abierta sigan contaminando el aire, la primera es utilizar un combustible de bajo contenido de azufre y nitrogeno, la segunda es controlar los parametros que afectan la combustion, y la tercera es tratar y/o limpiar los gases antes de emitirlos a la atmosfera. En este documento se presentan algunos tratamientos para disminuir las emisiones de contaminantes generados por la combustion en camara abierta.

  3. ESFER computer tool for the evaluation of photovoltaic systems used in rural electrification; ESFER herramienta de computadora para evaluar sistemas fotovoltaicos utilizados en electrificacion rural

    Energy Technology Data Exchange (ETDEWEB)

    Villasenor, Francisco; Perez, Miguel; Huacuz, Jorge M. [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1995-12-31

    ESFER (Evaluacion de Sistemas Fotovoltaicos para Electrificacion Rural) Photovoltaic Systems Evaluation for Rural Electrification is a computerized calculation tool for the analysis of information and evaluation of photovoltaic systems for rural electrification. This article describes such a tool, as well as the parameters that are taken into account for analyzing the systems, the methodology to qualify and the computer program operation. The graphic results of a typical case are presented. ESFER pretends to be a program of general use for the evaluation of photovoltaic systems for rural electrification. [Espanol] ESFER, Evaluacion de Sistemas Fotovoltaicos para Electrificacion Rural, es una herramienta de calculo computarizada para el analisis de informacion y evaluacion de sistemas fotovoltaicos para electrificacion rural. En el presente articulo se describe dicha herramienta, asi como los parametros que se toman en cuenta para analizar los sistemas, la metodologia de calificacion y la operacion del programa de computadora. Se presentan los resultados graficos de un caso tipico. ESFER pretende ser un programa de uso generalizado para la evaluacion de sistemas fotovoltaicos de electrificacion rural.

  4. Celulas solares e sensores de filme fino de silicio depositados sobre substratos flexiveis =

    Science.gov (United States)

    Pinto, Emilio Sergio Marins Vieira

    Celulas solares flexiveis de filmes finos de silicio sao geralmente fabricadas a baixa temperatura sobre substratos de plastico ou a mais elevadas temperaturas sobre folhas de aco. Esta tese reporta o estudo da deposicao de filmes finos sobre diferentes substratos de plastico, transparentes e coloridos, para celulas solares do tipo sobrestrato e substrato, respectivamente. Como objetivo co-lateral, os filmes dopados depositados sobre plastico foram usados como sensores de deformacao, utilizando as suas propriedades piezo-resistivas. Elevadas taxas de deposicao dos filmes de silicio depositados sobre plastico foram obtidas a baixa temperatura do substrato (150ºC) por rf-PECVD. A influencia de diferentes parametros de deposicao sobre as propriedades e taxa de deposicao dos filmes resultantes foram estudados e correlacionados. Celulas solares de filmes finos de silicio amorfo e microcristalino foram desenvolvidas a baixas temperaturas sobre plasticos. Eficiencias de 5 - 6.5% foram alcancadas para as celulas amorfas e 7.5% para as celulas microcristalinas. Efeitos de aprisionamento da luz foram estudados atraves da texturizacao por ablacao laser de substratos de plastico e corrosao umida de TCO sobre plastico. Filmes finos de silicio microcristalino, depositados por HW-CVD, com fator piezoresistivo de -32.2, foram usados para fabricar sensores de deformacao em uma membrana plastica muito fina (15 μm). Estruturas de teste em textil e a miniaturizacao dos sensores piezoresistivos depositados sobre substratos flexiveis de poliimida foram abordados.

  5. ELECTRICAL PROPERTIES OF Cr/CrN NANO-MULTILAYERS PRODUCED BY THE UNBALANCED MAGNETRON SPUTTERING TECHNIQUE

    Directory of Open Access Journals (Sweden)

    DIANA MARITZA MARULANDA CARDONA

    2011-01-01

    Full Text Available Peliculas de nitruro de cromo (CrN se han aplicado como recubrimientos protectores contra el desgaste y la corrosion debido a sus excelentes propiedades mecanicas y alta resistencia a la corrosion, y en el campo electronico debido a su baja resistividad. Sin embargo, se ha encontrado que las multicapas que combinan peliculas metal/ceramico podrian mejorar las propiedades en comparacion a sus contrapartes en monocapa debido al aumento e interaccion entre interfaces. En este trabajo se produjeron nano-multicapas de Cr/CrN a traves de la tecnica de sputtering con magnetron desbalanceado con tres grados de desbalanceo diferentes para estudiar la influencia de este parametro en las propiedades electricas. Se crecieron multicapas con un espesor total de aproximadamente 1 microm y un periodo de bicapa (A de 200 nm, 100 nm y 20 nm. Las multicapas se produjeron a temperatura ambiente sobre acero H13 y silicio (100 y se estudio su microestructura y las propiedades electricas en funcion del campo magnetico. La formacion de fases se caracterizo a traves de Difraccion de Rayos X y los resultados muestran las orientaciones (111 y (200 para todas las multicapas. Se obtuvieron imagenes de la seccion transversal a traves de Microscopia Electronica de Barrido y los resultados muestran la formacion de una estructura en multicapas.

  6. Evaluation of the different supported bifunctional electrocatalysts for unified regenerative cells; Evaluacion de diferentes soportes de electrocatalizadores bifuncionales para celdas regenerativas unificadas

    Energy Technology Data Exchange (ETDEWEB)

    Gurrola, M. P.; Torres-Amaya, D. S.; Duron-Torres, S. M.; Escalante-Garcia, I. L. [Universidad Autonoma de Zacatecas, Unidad Academica de Ciencias Quimicas, Zacatecas (Mexico)]. E-mail: duronsm@prodigy.net.mx; Arriaga-Hurtado, L.G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Pedro Escobedo, Queretaro (Mexico)

    2009-09-15

    un solo dispositivo. Los retos de estos sistemas son aun mayores que en las celdas de combustible convencionales, siendo el problema tecnico mas apremiante, la optimizacion del electrodo de oxigeno. Los altos potenciales de operacion de estos dispositivos en el modo electrolizador, E >1.6 V vs. ENH, limitan el empleo de electrodos de Pt soportados en Vulcan. El Pt no es lo suficientemente electroactivo para catalizar la reaccion de evolucion de oxigeno (OER) y a estos potenciales los soportes basados en carbon sufren corrosion. Ademas de los estudios sobre materiales que funcionen como catalizadores bifuncionales, un importante numero de investigaciones se estan dirigiendo a la busqueda de nuevas matrices para su uso como soportes de electrocatalizadores para la OER y ORR{sup 1,2}. En este trabajo, se presentan los resultados preliminares obtenidos para el estudio cinetico de las reacciones de oxigeno, sobre diferentes mezclas de Pt con IrO{sub 2} y RuO{sub 2} soportados en diferentes formas de carbon y oxidos de titanio subestequiometricos. Los estudios se realizaron empleando voltamperometria ciclica (CV) y lineal (LV) para la OER y electrodo disco rotatorio (EDR) para la ORR en soluciones acuosas de H{sub 2}SO{sub 4} 0.5M. La tecnica de cronoamperometria (CA) proporciono informacion de la estabilidad electroquimica de los electrodos. Los resultados indican que los electrodos soportados en diferentes formas de carbon disminuyen paulatinamente su desempeno como consecuencia de la corrosion al realizar las reacciones de reduccion y formacion de oxigeno en ciclos consecutivos. Los oxidos de titanio, le confieren una mayor estabilidad a electrodos construidos sobre ese material, significando que pudieran representar un potencial como soporte para electrodos de oxigeno basados en mezclas de Pt, IrO{sub 2} y RuO{sub 2} como electrocatalizadores bifuncionales para las URFC.

  7. Electrochemical study of oxygen reduction reaction in Pt/C catalysts synthesized by photo-deposition; Estudio electroquimico de la reaccion de reduccion de oxigeno en catalizadores de Pt/C sintetizados por fotodeposito

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Galindo, J. A.; Ruiz-Camacho, B.; Valenzuela-Zapata, M. A.; Gonzalez-Huerta, R. G. [IPN, ESIQIE, Mexico, D.F. (Mexico)]. E-mail: rosgonzalez_h@yahoo.com.mx

    2009-09-15

    interaccion entre estos dos componentes ha recibido mucha atencion en los ultimos anos. Esta interaccion es considerada como la responsable en los efectos de crecimiento de la estructura y la disminucion de la dispersion de las particulas del metal sobre el soporte, provocando un bajo desempeno global y un menor tiempo de vida util de la pila. Las propiedades del soporte se ven acentuadas en los catalizadores catodicos, donde se lleva a cabo la reaccion de reduccion de oxigeno por las condiciones de operacion que se tienen, actualmente se estan investigando sintesis que mejoren la interaccion metal-soporte y asi aumentar el tiempo de vida de la pila de combustible. En este trabajo se presenta el estudio electroquimico de catalizadores de tamano nanometrico de platino soportado en carbon (Pt/C) sintetizados por el metodo de Foto-deposito Quimico para determinar su efecto catalitico y estabilidad en la reaccion de reduccion de oxigeno en medio acido. Se utilizo como precursor de platino el C{sub 10}H{sub 14}O{sub 4}Pt (Pt(acac)2). El estudio electroquimico se realizo con las tecnicas de voltamperometria ciclica y electrodo de disco rotatorio observando que los catalizadores sintetizados presentan un comportamiento similar al Pt ETek. El estudio cinetico mostro un potencial a circuito abierto de 0.96 V, con una pendiente de Tafel de 73 mV dec-1 y a una corriente de 0.1 mA cm-2 se tiene un potencial de 0.91 V. Los autores agradecen el apoyo al ICYTDF (proyecto PICS08-37) y al IPN (Proyecto SIP-20090433).

  8. Isotopic data to study the mechanism of the oxidation of mercaptoacetic acid; Donnees isotopiques pour l'etude du mecanisme d'oxydation de l'acide mercaptoacetique; Izotopnyj metod issledovaniya mekhanizma okisleniya merkapgouksusnoj kisloty; Estudio del mecanismo de oxidacion del acido mercaptoacetico por medio de datos obtenidos con radioisotopos

    Energy Technology Data Exchange (ETDEWEB)

    Gal, D [Central Isotope Laboratory, University of Szeged (Hungary); Guczi, L [Department of Radiology, Elelmiszeripari Kutato Intezet, Budapest (Hungary)

    1962-03-15

    }S augmentait considerablement le taux d'absorption d'oxygene, tant dans le processus de catalysation par le fer qu'en l'absence de fer. Au cours de la reaction, on a mesure la concentration du sulfure, son activite specifique et son activite totale. En. partant de ces donnees, et en utilisant la methode d'etude cinetique au moyen d'isotopes, mise au point par Neiman et ses collaborateurs, on a pu calculer le taux de formation de sulfure et le taux de son oxydation ulterieure. La comparison de ces donnees avec d'autres donnees cinetiques revele que l'oxydation de l'acide mercaptoacetique en phase liquide est une reaction en chaine ramifiee, l'un des principaux elements de cette chaine etant la formation de Na{sub 2}S et son oxydation ulterieure. On a constate en outre qu'il se forme du sulfate, lors de la reaction, mais seulement a partir du sulfure mineral. Le fer catalyse la formation de disulfure organique et, de ce fait, influe aussi sur la formation de sulfure. (author) [Spanish] Numerosos investigadores han estudiado la autooxidacion en fase liquida, por oxigeno molecular, de compuestos que contienen un grupo mercaptano; si bien han llegado a la conclusion de que se forman sulfuros en el curso de la reaccion, el mecanismo exacto del proceso no se conoce. Los autores estudiaron la autooxidacion del acido mercaptoacetico a 50{sup o} C y pH 8 en presencia de complexon IV y de hierro. Anadieron al sistema Na{sub 2}S marcado con {sup 35}S y comprobaron que este compuesto aumenta notablemente la velocidad de absorcion de oxigeno tanto en las reacciones catalizadas por hierro como en las que transcurren en ausencia de iones de este metal. En el curso de la reaccion, los autores midieron la concentracion del sulfuro, su actividad especifica y su actividad total. Gracias a estos datos y empleando el metodo isotopico cinetico establecido por Neiman y colaboradores, pudieron calcular la velocidad de formacion del sulfuro y la velocidad de su oxidacion subsiguiente. Por

  9. Study of lithium extraction from brine water, Bledug Kuwu, Indonesia by the precipitation series of oxalic acid and carbonate sodium

    Science.gov (United States)

    Sulistiyono, Eko; Lalasari, Latifa Hanum; Mayangsari, W.; Prasetyo, A. B.

    2018-05-01

    Lithium is one of the key elements in the development of batteries for electric car applications. Currently, the resources of the world's lithium are derived from brine water and lithium mineral based on spodumene rock. Indonesia which is located in the area of the ring of fire, has potential brine water resources in some area, such as brine water from Bledug Kuwu, Central Java that used in this research. The purposes of this research are to characterize brine water, Bledug Kuwu and to investigate the influence of chemical solvents on Li, Na, K, Ca, Mg, Al, B ion precipitation from brine water. This research was done with 2 times the process of chemical precipitation that runs series as follows: 5 liters of brine water were chemically precipitated using 400 ml of 12.43 N oxalic acid and followed by chemical precipitation using 400 mL of 7.07 N sodium carbonate solutions. Evaporation and filtration processes were also done twice in an effort to separate white precipitate and filtrate. The filtrate was analyzed by ICP-OES and white precipitates (salts) were analyzed by SEM, XRD, and XRF. The result shows that oxalate precipitation process extracted 32.24% Al, 23.42% B, 22.43% Ca, 14.26% Fe, 3.21 % K, 9.86% Na and 14.26% Li, the following process by carbonate precipitation process extracted 98.86% Mg, 73% Ca, 22.53% Li, 82.04% Al, 14.38% B, 12.50% K, 2.27% Na. There is 63.21% lithium is not extracted from the series process. The SEM analysis shows that the structure of granules on the precipitated salts by oxalic acid form gentle cubic-shaped solid. In the other hand, oxalate precipitation followed by sodium carbonate has various particle sizes and the shape of crystals is fragments, prism and cube look like magnesium carbonate, calcium chloride, and calcite's crystal respectively. This is in accordance with XRD analysis that phases of whewellite (CaC2O4.H2O), disodium oxalate (Na2C2O4), magnesite (MgCO3), calcium lithium aluminum (Al1.19 Ca1Li0.81), dolomite (CaCO3

  10. Chemical-mineralogical characterization and Moessbauer spectroscopy of aquamarine from Pedra Azul, Northeast of Minas Gerais

    International Nuclear Information System (INIS)

    Viana, Rubia Ribeiro; Jordt-Evangelista, Hanna; Costa, Geraldo Magela da

    2001-01-01

    Aquamarines from three pegmatites located the vicinities of the Pedra Azul city, Minas Gerais state, were investigated in terms of chemical composition, physical properties and Moessbauer spectroscopy. The small lenticular pegmatite bodies are usually less than 5 m wide and exhibit a conspicuous mineralogical and textural zoning. The last thermal event in these pegmatites, determined by K-Ar method in muscovite, is of Neo proterozoic age, coincident with the late stages of the Brasiliano tectono- metamorphic cycle. Chemical analyses showed that sodium is the alkali with higher contents in the aquamarines, thus enabling their classification as sodic beryls. In zoned samples there is an increase of Fe as well as Mn from center to border, while no systematic variation could be detected for other elements. The specific gravity of 2.72 to 2.80 g/cm 3 is higher than the values determined for samples from other pegmatites of Minas Gerais. The refraction indices are ne=1.569 - 1.579 and NW= 1.573 - 1.581 and the birefringence varies from 0.002 to 0.008. The refraction indices increase with the Be O content. The color of aquamarines varies from medium to light blue, sometimes greenish blue. Moessbauer spectra obtained at room temperature and at 80 K show that Fe 2+ is the main chromophore-ion and suggest that the iron is present in octahedral sites as well as in the structural channels. Moessbauer spectra also indicate that the incorporation of Fe 3+ may cause a shift from deep blue to light blue colors. Based on their aquamarine composition the pegmatites were classified as barren, poor in rare alkalis (Li, Rb, Cs) and therefore little differentiated. The relatively simple mineralogy and the lack of lithium minerals such as lepidolite and spodumene confirm this classification. Thus, the composition of beryl can be used as a tracer for the prospection of pegmatites with different degrees of differentiation and consequently with different types of mineralization. (author)

  11. Complex Diffusion Mechanisms for Li in Feldspar: Re-thinking Li-in-Plag Geospeedometry

    Science.gov (United States)

    Holycross, M.; Watson, E. B.

    2017-12-01

    In recent years, the lithium isotope system has been applied to model processes in a wide variety of terrestrial environments. In igneous settings, Li diffusion gradients have been frequently used to time heating episodes. Lithium partitioning behavior during decompression or cooling events drives Li transfer between phases, but the extent of Li exchange may be limited by its diffusion rate in geologic materials. Lithium is an exceptionally fast diffuser in silicate media, making it uniquely suited to record short-lived volcanic phenomena. The Li-in-plagioclase geospeedometer is often used to time explosive eruptions by applying laboratory-calibrated Li diffusion coefficients to model concentration profiles in magmatic feldspar samples. To quantify Li transport in natural scenarios, experimental measurements are needed that account for changing temperature and oxygen fugacity as well as different feldspar compositions and crystallographic orientation. Ambient pressure experiments were run at RPI to diffuse Li from a powdered spodumene source into polished sanidine, albite, oligoclase or anorthite crystals over the temperature range 500-950 ºC. The resulting 7Li concentration gradients developed in the mineral specimens were evaluated using laser ablation ICP-MS. The new data show that Li diffusion in all feldspar compositions simultaneously operates by both a "fast" and "slow" diffusion mechanism. Fast path diffusivities are similar to those found by Giletti and Shanahan [1997] for Li diffusion in plagioclase and are typically 10 to 20 times greater than slow path diffusivities. Lithium concentration gradients in the feldspar experiments plot in the shape of two superimposed error function curves with the slow diffusion regime in the near-surface of the crystal. Lithium diffusion is most sluggish in sanidine and is significantly faster in the plagioclase feldspars. It is still unclear what diffusion mechanism operates in nature, but the new measurements may impact

  12. Crotalaria incana l. and leucaena leucocephala lam. (leguminosae): toxicity indicator species of petroleum hydrocarbons in soil; Crotalaria incana l. y leucaena leucocephala lam. (leguminosae): especies indicadoras de toxicidad por hidrocarburos de petroleo en el suelo

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez Luna, Dinora; Castellan Estrada, Mepivoseth; Rivera Cruz, Maria del C.; Ortiz Ceballos, Angel I.; Izquierdo R., Francisco [Colegio de Postgraduados, Campus Montecillo, Montecillo, Estado de Mexico (Mexico)]. E-mail: dinovaz@colpos.mx

    2010-07-01

    This study assesses the toxic effects produced by a Gleysol molic soil contaminated with crude oil on seedlings of two species of legumes. A phytotoxic impact index (IIF) was generated, which includes five parameters measured by relative rates of impact (IRIF{sub (x)}) for variables; emergency, height, root length, aboveground biomass and root biomass. Bioassays were conducted under a completely randomized design with three replications under semi-controlled conditions, to assess the sensitivity of Leucaena leucocephala and Crotalaria incana at different concentrations of TPH (total petroleum hydrocarbons). Effects were highly significant (P {<=} 0.01) with increasing concentrations of HTP in substrate. The emergence of L. leucocephala was 29 % lower with 80 000 mgkg{sup -1} HTP, while C. incana decreased 30 % with 32 000 mgkg{sup -1} TPH respect to control. Both species showed a five-day delay in the emergence of seedlings when exposed to high levels of TPH. A significant decrease in the accumulation of dry matter (DM) at concentrations above 20 000 mgkg{sup -1} TPH was observed in both species. The respective IIF declined of 50 % with 80 000 and 25 000 mgkg{sup -1} TPH, but L. leucocephala had no significant effect with 10 000 mgkg{sup -1} TPH. Finally, the EC50 in L. leucocephala, is presented with 80 000 mgkg{sup -1} TPH whereas in C. incana this parameter is noted from 25 000 mgkg{sup -1} TPH. [Spanish] En este estudio se evaluaron los efectos toxicos que produce un suelo Gleysol molico contaminado con petroleo crudo, sobre plantulas de dos especies de leguminosas. Para ello se genero un indice de impacto fitotoxico (IIF) que integra cinco parametros, medidos a traves de indices relativos de impacto (IRIF{sub (x)}) para las variables emergencia, altura, longitud radicular, biomasa aerea y biomasa radicular. Los bioensayos se realizaron bajo un diseno completamente al azar, con tres repeticiones, en condiciones semicontroladas, para evaluar la sensibilidad de

  13. Wave transmission over permeable submerged breakwaters; Transmision del oleaje en rompeolas sumergidos permeables

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-y-Zurvia-Flores, Jaime Roberto; Fragoso-Sandoval, Lucio [Instituto Politecnico Nacional(Mexico)

    2008-10-15

    caso de la proteccion de playas turisticas en Mexico. En investigaciones previas, como las de D' Angremond et al. (1996), Seabrook y Hall (1998), y Briganti et al. (2003), las ecuaciones empiricas presentadas proveen informacion limitadas sobre la distribucion espacial de la energia del oleaje sobre la estructura, motivo por el cual se decidio realizar un estudio en modelo fisico reducido de rompeolas sumergidos permeables, fundamentado en los resultados presentados por los investigadores antes citados y con vista a posibles aplicaciones. Por lo tanto, en este trabajo se describe el desarrollo de un estudio de transmision del oleaje sobre rompeolas sumergidos permeables, realizado en un modelo fisico, en el cual se probaron diferentes secciones de rompeolas de tipo trapecial constituidos por enrocamiento. El estudio se efectuo en un canal de oleaje angosto, servido de un sistema generador de oleaje irregular hidraulico controlado por computadora. Este sistema se utilizo para generar y reproducir las condiciones de oleaje irregular requeridas en los ensayos. Para medir y procesar los datos de oleaje del modelo, se dispuso de un olografo con sensores de oleaje resistivos, controlado a traves de un sistema computarizado. El objetivo central del estudio fue determinar experimentalmente la influencia de los diferentes parametros de los rompeolas sumergidos sobre el coeficiente de transmision de oleaje. Asimismo, se compararon nuestros resultados experimentales con los obtenidos con las formulas de D' Angremond et al. (1996), y la de Seabrook y Hall (1998). Los resultados muestran que los parametros de mayor influencia en la transmision del oleaje son la sumergencia relativa y el ancho de corona relativo, y que la formula de Seabrook y Hall responde mejor a lo aqui obtenido.

  14. Evaluation and tuning of control algorithms for power system stabilizers; Evaluacion y sintonizacion de algoritmos de control para el estabilizador de sistemas de potencia

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez Gonzalez, Miguel

    1998-08-01

    A procedure based on the phase compensation technique for tuning satisfactorily lead-lag power system stabilizers (PSS) is presented in this work. This procedure can be applied to standard models of PSS`s (with two phase compensation stages) where rotor speed deviation or an equivalent rotor speed signal is used as input. An analysis of several state of the art advanced control schemes is also presented, which are proposed for overcoming the limitations of conventional fixed parameters PSS`s. The advantages and drawbacks in designing certain types of PSS`s which are based on adaptive control, fuzzy logic and neural networks techniques are investigated. Based on this study, and taking into account the highly complex and non-linear nature of power systems, a fuzzy logic PSS is designed. In order to have good damping characteristics, speed deviation ({Delta}{omega}) of a machine and its acceleration ({Delta}{omega}) are chosen as the input signals to the fuzzy stabilizer of that particular machine. The performance of the lead-lag PSS and fuzzy stabilizer are validated through the simulation of two case studies: a single machine-infinite bus system, and a multimachine power system. All simulations were performed using a tool based on algorithms developed in MATLAB for the study of power system stability. [Espanol] Se presenta un procedimiento basado en la tecnica de compensacion de fase para ajustar en forma satisfactoria los parametros de los estabilizadores de sistemas de potencia (ESP) del tipo de adelanto-atraso. Este procedimiento es aplicable a modelos estandar de ESP`s (con dos redes de compensacion de fase) que utilizan como senal de entrada la velocidad del rotor del generador en cuestion, o una senal de velocidad equivalente. Por otra parte, se realiza un estudio de diversos esquemas de control avanzado del ESP que se proponen en la literatura actual para superar las limitantes de los estabilizadores convencionales. Basicamente, se analizan las ventajas y

  15. Analyzing ground ozone formation regimes using a principal axis factoring method: A case study of Kladno (Czech Republic) industrial area

    Energy Technology Data Exchange (ETDEWEB)

    Malec, L.; Skacel, F. [Department of Gas, Coke and Air Protection, Institute of Chemical Technology in Prague, (Czech Republic)]. E-mail: Lukas.Malec@vscht.cz; Fousek, T. [Institute of Public Health, District of Central Czech Republic, Kladno (Czech Republic); Tekac, V. [Department of Gas, Coke and Air Protection, Institute of Chemical Technology in Prague, (Czech Republic); Kral, P. [Institute of Public Health, District of Central Czech Republic, Kladno (Czech Republic)

    2008-07-15

    ). Segundo, interpretamos un conjunto de datos mediante el analisis factorial (FA) para examinar las diferencias entre los procesos de generacion de ozono entre las epocas de verano e invierno. Para evitar la dependencia de la temperatura de las variables, asi como para describir los procesos troposfericos de lavado de las sustancias contaminantes, utilizamos el contenido de vapor de agua en vez del parametro de humedad relativa, empleado muy a menudo. De esta manera fuimos capaces de definir con exito los diferentes procesos de generacion de ozono y posteriormente estimarlos junto con la descomposicion espacial de sus precursores. La temperatura elevada del aire, la radiacion y el bajo contenido de agua estan relacionados con los episodios de contaminacion en verano, mientras que la radiacion y la velocidad del viento resultan ser los parametros mas importantes durante el invierno. Resulto en mayores flujos de escurrimiento foliar y acumulacion en el suelo de N, S, y Mg comparado con doseles de pino o areas abiertas. El elevado deposito atmosferico altera los procesos funcionales del ecosistema, particularmente el escurrimiento foliar y el ciclo interno de nutrientes, y este efecto depende de la cobertura y especie arborea.

  16. Tidal currents in the Yucatan Channel

    Energy Technology Data Exchange (ETDEWEB)

    Carrillo Gonzalez, Fatima [Centro Universitario de la Costa, Universidad de Guadalajara, Guadalajara, Jalisco (Mexico); Ochoa, Jose; Candela, Julio; Badan, Antonio; Sheinbaum; Gonzalez Navarro, Juan Ignacio [Departamento de Oceanografia Fisica, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Ensenada, Baja California (Mexico)

    2007-07-15

    Currents data from a ten-month period at 197 measuring points covering all Yucatan Channel were processed by harmonic analysis to estimate tidal parameters for the O{sub 1}, K{sub 1}, M{sub 2} and S{sub 2} components. The highly detailed coverage confirms the known dominance for the O{sub 1} and K{sub 1} diurnal components, but also showed, for the first time, their intensification in the deep eastern margin of the channel where maximum amplitudes in main axis are 17 and 19 cm.s{sup -}1. The data also confirms weak semi-diurnal components, of which the most intense, M{sub 2} and S{sub 2}, have amplitudes only up to 2 cm.s{sup -}1. The tidal ellipses were elongated (i.e. with eccentricities close to one) in the NNW direction. The O{sub 1}, K{sub 1}, M{sub 2} and S{sub 2} contributions in transport variability through the channel have amplitudes of 11.7, 12.5, 1.2 and 1.0 Sv, all well determined above noise. [Spanish] Se presentan, a detalle sin precedente, las caracteristicas de las corrientes de marea O{sub 1}, K{sub 1}, M{sub 2} y S{sub 2} en el canal de Yucatan. Mapas de los parametros que definen las elipses, como son las amplitudes en los ejes principales, la orientacion, la fase y la razon-senal-ruido se obtienen, por el clasico analisis armonico en mediciones de 10 meses en duracion, en 197 puntos que cubren ampliamente un plano vertical del canal. En acuerdo con reportes anteriores, las senales diurnas O{sub 1} y K{sub 1} dominan, demostrandose aqui que sus amplitudes alcanzan, en la parte profunda y Este, 17 y 19 cm.s{sup -}1. El analisis tambien revela senales semidiurnas M{sub 2} y S{sub 2} muy debiles con amplitudes maximas de 2 y 1cm.s{sup -}1. Las elipses son muy alargadas (i.e. con excentricidad cercana a uno) y orientadas al nornoroeste. Los valores de la razon senal a ruido indican que los parametros de las dos constituyentes diurnas se encuentran bien determinados, mientras que las semidiurnas quedan muy contaminadas por el ruido. El rasgo mas

  17. Second law characterization of stratified thermal storage tanks

    Energy Technology Data Exchange (ETDEWEB)

    Fraidenraich, N [Departamento de Energia Nuclear-UFPE (Brazil)

    2000-07-01

    de la primera ley de la termodinamica no existe diferencia entre los tanques de almacenamiento con la misma masa y temperatura promedio aun si tienen diferentes estructuras termicas estratificadas. No obstante la energia termica util que puede obtenerse de ellos puede diferir significativamente. En este trabajo derivamos una expresion capaz de caracterizar la configuracion estratificada del fluido termico. Usando los resultados obtenidos mediante la termodinamica de procesos irreversibles, este procedimiento adoptado consiste en calcular el maximo trabajo que se puede obtener de la capa termica que el tanque es capaz de desarrollar. Llegamos entonces a una expresion adimensional, el parametro de estratificacion (SP) que depende de la fraccion de masa y de la temperatura absoluta de cada termica asi como tambien la temperatura promedio del fluido termico. Se dan ejemplos numericos para diferentes tipos de estratificacion en el tanque y se verifica que la expresion obtenida es sensible a pequenas diferencias en la configuracion del almacenamiento termico. Por ejemplo un almacenamiento con temperaturas iguales a 74, 64 y 54 grados Celsius con su masa igualmente distribuida a lo largo del tanque rinde para el parametro SP una cifra igual a 0.000294. Por otra parte un tanque de almacenamiento con la misma temperatura promedio pero con diferentes temperaturas de las capas 76, 64, y 52 grados Celsius, tambien con distribucion uniforme de masa, rinde para SP un valor igual a la evaluacion cuantitativa de la estructura de estratificacion de almacenamientos termicos.

  18. Calculation of uncertainties; Calculo de incertidumbres

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Asencio, Misael [Centro de Estudios Ambientales de Cienfuegos (Cuba)

    2012-07-01

    metodologico para la obtencion de informacion (mesurando) de un sistema material (poblacion). Ello supone la necesidad de la definicion del problema, la eleccion de los metodos de muestreo y medicion adecuados y la ejecucion de estas actividades para la obtencion de la informacion. El resultado de una medicion solo es una aproximacion o estimacion del valor del mesurando, el cual se completa solo cuando va acompanado por una estimacion de la incertidumbre del proceso analitico. Segun el 'Vocabulario de Terminos Basicos y Generales de Metrologia' la incertidumbre de medicion 'es el parametro asociado con el resultado de la medicion que caracteriza la dispersion de los valores que razonablemente pudiera ser atribuida al mensurando (o magnitud). Este parametro podria ser una desviacion estandar o un intervalo de confianza'. La evaluacion de la incertidumbre exige que observemos detalladamente todas sus posibles fuentes, pero no de forma desproporcionada. Podemos realizar una buena estimacion de la incertidumbre concentrando el esfuerzo en las mayores contribuciones. Los pasos fundamentales del proceso de determinacion de la incertidumbre en las mediciones son: - la especificacion del mesurando; - la identificacion de las fuentes de incertidumbre; - la cuantificacion de las componentes individuales de la incertidumbre; - el calculo de la incertidumbre estandar combinada; - informe de la incertidumbre.

  19. Diesel oil combustion in fluidized bed; Combustion de aceite diesel en lecho fluidizado

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Cazares, Mario [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1992-07-01

    The effect of the fluidized bed depth in the combustion in burning diesel oil in a fluidized bed, was analyzed. A self sustained combustion was achieved injecting the oil with an injector that utilized a principle similar to an automobile carburetor venturi. Three different depths were studied and it was found that the deeper the bed, the greater the combustion efficiency. Combustion efficiencies were attained from 82% for a 100mm bed depth, up to 96% for a 200mm bed depth. The diminution in the efficiency was mainly attributed to unburned hydrocarbons and to the carbon carried over, which was observed in the black smoke at the stack outlet. Other phenomena registered were the temperature gradient between the lower part of the bed and the upper part, caused by the fluidization velocity; additionally it was observed that the air employed for the oil injection (carbureting air) is the most important parameter to attain a complete combustion. [Espanol] Se analizo el efecto de la profundidad del lecho en la combustion al quemar aceite diesel en un lecho fluidizado experimental. Se logro combustion autosostenida inyectando el aceite con un inyector que utilizo un principio similar al venturi del carburador de automovil. Se estudiaron tres diferentes profundidades del lecho y se encontro que a mayor profundidad del lecho, mayor eficiencia de la combustion. Se lograron eficiencias de la combustion desde 82% para el lecho de 100 mm de profundidad hasta 96% para el de 200 mm. La disminucion de la eficiencia se atribuyo, principalmente, a los hidrocarburos no quemados y al carbon arrastrado, lo cual se observo en el humo negro a la salida de la chimenea. Otros fenomenos registrados fueron el gradiente de temperatura entre la parte baja del lecho y la parte superior causado por la velocidad de fluidizacion; ademas, se observo que el aire utilizado para inyectar el aceite (aire de carburacion) es el parametro mas importante para lograr una combustion completa.

  20. Methane conversion factors from cattle manure in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Avalos, E E:mail: egavalos@imp.mx [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico); Ruiz-Suarez, L G [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    2007-01-15

    Methane emission factors from different cattle manure management systems including simulated slurry system fermentation were experimentally determined in this and a previous study (Gonzalez-Avalos and Ruiz-Suarez, 2001). Combining results from both studies, we report values for maximum CH4 yield, called B0, for manure produced by cattle under different production systems and climates, which also implies different quality of feeds and associated methane conversion factors (MCF) for distinct manure management systems. This set of data has the same functionality than that of the current IPCC methodology, but offer a wider set of key parameters to estimate methane emissions from manure, which may be of interest in other countries. In this work, we report MCF can be up to 17.3 times smaller than those suggested in the 1996 Revised IPCC Methodology Guidelines (IPCC, 1997) and Good Practice Guidance (IPCC, 2000). [Spanish] Los factores de emision de metano de diferentes sistemas de manejo de excretas, incluyendo la simulacion de la fermentacion en un sistema de lechada, fueron determinados experimentalmente en este trabajo y en otro anterior (Gonzalez-Avalos y Ruiz-Suarez, 2001). Al combinar ambos, se obtuvieron valores para la produccion maxima de metano (B0) provenientes de excretas producidas por ganado bovino de diferentes sistemas de produccion y climas, lo cual implica diversas calidades de alimento y factores de conversion de metano (MCF) dependiendo de los sistemas de manejo de excretas. Este conjunto de datos tiene la misma funcionalidad que los de la metodologia actual del IPCC, pero ofrece un conjunto de parametros mas amplio para estimar las emisiones de metano por excretas, lo cual puede ser de interes en otros paises. En este trabajo se reporta que los MCF pueden ser hasta 17.3 veces mas pequenos que los sugeridos en las Directrices de la Metodologia Revisada del IPCC de 1996 (IPCC, 1997) y en la Guia de Buenas Practicas (IPCC, 2000).

  1. Cleaning of contaminated soils with hydrocarbons by biocell; Saneamiento de suelos contaminados con hidrocarburos mediante biopilas

    Energy Technology Data Exchange (ETDEWEB)

    Iturbe-Arguelles, R.; Flores-Torres, C; Chavez-Lopez, C.; Roldan-Martin, A [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    2002-03-01

    In 1990 the Instituto de Ingenieria de la UNAM, initiated an evaluation through the soil and groundwater sampling and a risk health assessment in a Mexican refinery. An extended area was found contaminated with hydrocarbons. This area requires a soil remediation, taking into account that some zones present more than 30 000 mg/kg of Total Petroleum Hydrocarbons (TPH). Biopile system was recommended as the best remediation method to diminish TPG and some poliaromathic hydrocarbons (PAH). Therefore an experimental biopile of 30 m3 was constructed with contaminated soil. After 22 weeks, results show more than 80 % of TPH and PAH remotion. [Spanish] El grupo de saneamiento de suelos y acuiferos del Instituto de Ingenieria de la UNAM, inicio en 1999 la evaluacion de la contaminacion del subsuelo de una refineria en una zona costera del pais, mediante el muestreo de 425 puntos a 1.5 m de profundidad y con el analisis de los siguientes parametros: hidrocarburos totales del petroleo (HTP), hidrocarburo poliaromaticos (HAP), diesel, gasolina, metilterbutileter (MTBE) y los metales hierro, vanadio, zinc, cadmio, cromo y plomo. Asimismo, se lleva a cabo una evaluacion de riesgo a la salud a fin de determinar los niveles de limpieza de las areas contaminadas. Una vez realizado el estudio se propuso probar a nivel piloto dos tecnicas de saneamiento para las areas contaminadas con valores superiores a 30 000 mg/Kg de http, o bien, para las zonas en donde la evaluacion de riesgo a la salud indica la existencia de riesgo para uno o mas compuestos. Las tecnicas propuesta son biopilas y lavado de suelos con surfactantes. En este trabajo se presenta la prueba piloto con biopilas, de la cual se obtuvo una eficiencia de remocion de http del 80 porciento con cinco meses de operacion. Se muestra las partes de una biopila y se dan los resultados de la biopila experimental en la refineria Francisco I. Madero.

  2. Control y presión al comer en madres de preescolares costarricenses, y su relación con la clase social, la escolaridad, las prácticas de alimentación temprana y el índice de masa corporal de sus hijos e hijas

    Directory of Open Access Journals (Sweden)

    Alejandro Chacón-Villalobos

    2011-01-01

    Full Text Available El objetivo planteado en este trabajo fue el de caracterizar la presion y el control al comer que ejercen madres de preescolares costarricenses de clase alta y baja, evaluando relaciones con el IMC de sus hijos, el tipo de lactancia, la ablactacion, la escolaridad de la madre y su dedicacion al hogar. Para ello se solicito a 102 madres de clase alta y 121 de clase baja completar una encuesta validada (alpha de Cronbach de 0,7 basada en escalas de Likert, para cuantificar, ademas de la informacion general requerida, los niveles de control y presion. Adicionalmente, se determino el IMC segun genero de sus hijos preescolares (102 ninos de clase alta y 103 de clase baja. Para el estudio de los datos se utilizaron pruebas de t-Student y analisis de varianza, asi como correlaciones y evaluaciones de chi cuadrado. Se establecio una tendencia al sobrepeso en ambos sexos en la clase alta, la cual contrasta con las ninas pobres quienes tienden al bajo peso. Se evidencio una mayor frecuencia de trabajo fuera del hogar en la clase baja (p=0,008, siendo la introduccion de alimentos solidos mas temprana (p=0,04. La leche materna fue la opcion mas empleada en ambas clases sociales para el neonato. Ambas clases mostraron "control" y "presión" altas, especialmente entre las madres de clase social baja que trabajan fuera del hogar (p=0,0001. Ambos parametros correlacionan de manera positiva moderada (r=0,44; alpha=0,05. La correlación es mas fuerte entre la clase alta (r=0,54, sobre todo en las niñas (r=0,6.

  3. Caracterização farmacognóstica do jambolão (Syzypiam cumini (L. Skeels

    Directory of Open Access Journals (Sweden)

    J.R. Alberton

    Full Text Available A padronização de um fitoterápico é etapa imprescindível para garantia da qualidade de medicamentos contendo plantas medicinais. Objetivou-se padronizar Syzygiam cumini (L. Skeels e para tanto se estabeleceram parametros tais como, avaliação morfoanatômica das folhas, morfológica das flores e dos frutos, avaliação granulométrica da droga rasurada (frutos, determinação da umidade, avaliação dos processos de secagem, determinação do teor de extrativos e do teor de taninos (monômeros e polimeros. O estudo anatômico das folhas revelou a inexistência de pêlos no sistema dérmico, assim como a ocorrência de glândulas secretoras, drusas, colênquima e esclerênquima. As flores são hermafroditas, com androceu polistêmone e gineceu com ovário ínfero, gamocarpelar, bilocular com placentação axial. Observou-se elevado teor extrativo (38,57%. O diâmetro médio de partícula dos frutos secos moídos ficou em 0,630 mm. O processo de secagem dos frutos influenciou o teor de taninos totais. O teor de taninos determinado ficou em 5,10% para monômeros e 11,30% para os polimeros.

  4. Monitoring and control system for the charging of batteries in photovoltaic applications; Sistema para monitorizar y controlar la carga de baterias en aplicaciones fotovoltaicas

    Energy Technology Data Exchange (ETDEWEB)

    Ortega S, Cesar A; Pacheco A, Maria Jojutla; Orozco V, Jaime A; Cristin V, Miguel A [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2004-07-01

    The appropriate monitoring and control of the charging of lead-acid (LAB) batteries is an increasing necessity in an industry that demands systems with low maintenance costs and high availability. The problem of extending the batteries useful life becomes more complex when the batteries are charged through photovoltaic panels. The purpose of the present article is to offer the description of the system for monitoring and control for the charging of batteries developed at the Instituto de Investigaciones Electricas (IIE). This system performs a continuous monitoring of the charging state of the battery and of the main operation parameters. With the extracted information of the data, the fine tuning algorithm control can be made. The data are acquired in a personal computer through a serial connection. Once stored, they are presented to the user in a graphical way so that they can be analyzed. [Spanish] El adecuado monitoreo y control de carga de baterias plomo-acido (BPA) es una necesidad creciente en una industria que demanda sistemas con bajos costos de mantenimiento y alta disponibilidad. El problema de extender la vida util de las baterias se vuelve mas complejo cuando las baterias son cargadas a traves de paneles fotovoltaicos. La intencion del presente articulo es ofrecer la descripcion del sistema para monitoreo y control de carga de baterias desarrollado en el Instituto de Investigaciones Electricas (IIE). Este sistema realiza un monitoreo continuo del estado de carga de la bateria y de los principales parametros de operacion. Con la informacion extraida de los datos, se puede hacer la sintonizacion fina del algoritmo de control. Los datos se adquieren en una computadora personal a traves de un enlace serial. Una vez almacenados, se presentan al usuario de manera grafica para que puedan ser analizados.

  5. Contribution to the scintillation detection optimization in double phase detectors for direct detection of dark matter

    Science.gov (United States)

    Balan, Catalin

    Na ultima decada, foram feitos grandes progressos no desenvolvimento dos detetores de detecao direta das particulas que constituem a materia negra. Com estrategias do aumento gradual do volume do alvo e, simultaneamente, de reducao dos niveis de fundo, a experiencia XENON obteve resultados muito bons e perspetivas promissoras para a detecao de materia negra. Tarefas relativas a analise de dados experimentais adquiridos com o detetor de dupla fase em uso, assim como as simulacoes do campo eletrico, desenvolvimento, montagem e testes para o proximo detetor XENON1T, assim como a participacao regular na manutencao geral e monitorizacao do prototipo atual XENON100 no LNGS, constituiram o plano de trabalhos para as atividades de investigacao do presente doutoramento e a minha contribuicao para a otimizacao da detecao de cintilacao nos detetores da experiencia XENON. A necessidade de alcancar niveis elevados de sensibilidade, requer inovacao em todos os aspetos fisicos do detetor, assim como a reducao de todas as fontes de radioatividade que contribuem para o fundo. O modo mais indicado de operacao para os detetores com enchimento a Xe no estado liquido e gasoso envolve a medicao da cintilacao primaria e da secundaria provenientes da interacao das particulas no Xe liquido. A razao entre estes dois sinais permite diferenciar claramente a maior parte dos eventos correspondentes as fundo dos eventos correspondentes a WIMPs. Deste modo, a leitura dos sinais correspondentes a cintilacao e de extrema importancia. A amplitude do sinal de cintilacao antes dos fotossensores e maximizada atraves da otimizacao de varios parametros, tais como a geometria do alvo do detetor, a transparencia das grelhas dos eletrodos, a uniformidade do ganho em cintilacao secundaria e a utilizacao de material reflectivo para cobrir as superficies que nao sao fotossensiveis.

  6. Operational performance of the Avispa-IIE wind generator in microhybrid systems

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Galarza, Raul; Mejia Neri, Fortino [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1997-12-31

    The purpose of this paper is to make a general analysis over the operational performance of the Avispa-IIE wind generator in an Solar-Eolic hybrid installation, at an eco-tourist resort. This work was performed through the monitor of the wind generator and the system itself throughout a year, for the acquisition taking the variables of interest and operational parameters that might allow to characterize and to evaluate the general behavior of the system. Herein are the principals characteristics of the wind generator; its performance curve, the basic configuration of the installation and the control philosophy; Likewise, some technical and human problems which arise during the operation of the system are included, the implementation of improvements in the wind generator and the general results acquired during the time of operation of the wind generator in the cited installations. [Espanol] El proposito de este articulo es el hacer un analisis general del comportamiento operacional del aerogenerador Avispa-IIE en una instalacion hibrida Solar-Eolica en un lugar de veraneo eco-turistico. Este trabajo ha sido llevado a cabo mediante el monitor del aerogenerador y el sistema mismo por espacio de un ano, para la adquisicion de las variables de interes y de los parametros operacionales que pudieran servir para caracterizar y evaluar el comportamiento general del sistema. Aqui se incluyen las caracteristicas principales del aerogenerador; su curva de comportamiento, la configuracion basica de la instalacion y la filosofia del control. De la misma manera se incluyen algunos problemas tecnicos y humanos que se originan durante la operacion del sistema y la puesta en practica de las mejoras del aerogenerador y los resultados generales adquiridos durante el tiempo de operacion del aerogenerador en las instalaciones citadas.

  7. The atomization and the flame structure in the combustion of residual fuel oils; La atomizacion y estructura de flama en la combustion de combustibles residuales

    Energy Technology Data Exchange (ETDEWEB)

    Bolado Estandia, Ramon [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1986-12-31

    In this article a research on the combustion of heavy residual fuel oils is presented. The type of flames studied were obtained by means of the burning of sprays produced by an atomizer designed and calibrated specially for the research purpose. The flame characteristics that were analyzed are its length, its luminosity, the temperature, the distribution of the droplets size and mainly the burning regime of the droplets in the flame. The experimental techniques that were used for these studies were shadow micro-photography, suction pyrometry and of total radiation, laser diffraction, 35 mm photography, and impact push. The analysis of the experimental results, together with the results of the application of a mathematical model, permitted to establish two parameters, that quantitatively related determine the burning regime of the droplets in a flame of sprays of residual heavy fuel oil. [Espanol] En este articulo se presenta una investigacion sobre la combustion de combustibles residuales pesados. El tipo de flamas estudiadas se obtuvieron mediante el quemado de sprays producidos por un atomizador disenado y calibrado especialmente para el proposito de la investigacion. Las caracteristicas de flama que se analizaron son la longitud, la luminosidad, la temperatura, la distribucion de tamano de gotas y, principalmente, el regimen de quemado de gotas en la flama. Las tecnicas experimentales que se usaron para estos estudios fueron microfotografia de sombras, pirometria de succion y de radiacion total, difraccion laser, fotografia de 35 mm y empuje de impacto. El analisis de resultados experimentales, junto con los resultados de la aplicacion de un modelo matematico, permitio establecer dos parametros, que relacionados cuantitativamente, determinan el regimen de quemado de gotas en una flama de sprays de combustible residual pesado.

  8. Design and implementation of the 40, 50/51 protections and MEL, OEL and V/HZ limiters in a synchronous generator; Diseno e implementacion de las protecciones 40,50/51 y limitadores MEL, OEL y V/HZ en un generador sincrono

    Energy Technology Data Exchange (ETDEWEB)

    Goitia Ochoa, Salvador Hector

    2001-10-15

    The thesis shows the design and implementation of loss of field (40) and overcurrent (50/51) relays, minimum excitation limiter (MEL), over excitation limiter (OEL) and Voltage / Frequency limiter (V/Hz). It is also shown the development of a synchronous machine mathematical model for representing the conditions of open circuit, three phase short-circuit at stator terminals and short/open circuit at the field winding. Finally, a study about the magnetic saturation effect on the protection against loss of excitation is shown. It is studied the effects on the relay settings by using the X{sub d} saturated reactance. All the tests were applied for a salient-pole synchronous machine of 7 kVA, 220 V and 1800 rpm. The machine is at the Propulsion Laboratory of the Instituto Tecnologico de La Laguna. [Spanish] En este trabajo de tesis se realiza el diseno e implementacion de las protecciones contra la perdida de campo (40) y de sobrecorriente (50/51), asi como el de los limitadores de minima excitacion (MEL), maxima excitacion (OEL) y el limitador de Voltaje / Frecuencia (V/Hz). Ademas se muestra el desarrollo de las ecuaciones del modelo matematico del generador sincrono en condiciones de circuito abierto, con una falla trifasica en terminales, con el devanado de campo en corto circuito y en circuito abierto. Por ultimo se realiza un estudio en el cual se incluye el efecto de la saturacion magnetica en la proteccion contra la perdida de campo y las consecuencias que traeria el ajustar la proteccion usando el parametro de X{sub d} saturada. Las pruebas fisicas de las protecciones y limitadores fueron aplicadas a un generador sincrono de polos salientes con una capacidad de 7 kVA, 220 V, 1800 rpm, localizado en el Laboratorio de Propulsion de Instituto Tecnologico de la laguna.

  9. Substâncias fenólicas, flavonoides e capacidade antioxidante em erveiras sob diferentes coberturas do solo e sombreamentos

    Directory of Open Access Journals (Sweden)

    T.S. FERRERA

    Full Text Available RESUMO Objetivou neste trabalho analisar a concentração de polifenóis totais, flavonoides e capacidade antioxidantes por meio dos métodos ABTS e FRAP, em erveiras jovens cultivadas em solo coberto e com sombreamento. Mudas de erva-mate foram submetidas aos tratamentos com solos cobertos e desnudos em sombreamentos de 0, 18, 35 e 50%, após sete e onze meses de cultivo, verão e outono, respectivamente. Foram coletadas folhas maduras para realização dos extratos utilizados para as análises de compostos fenólicos por meio da reação de oxirredução com reagente de Folin-Ciocalteu, flavonoides por método colorimétrico e capacidade antioxidante por frente ao radical ABTS e poder de redução do ferro (FRAP. O teor de compostos fenólicos foi maior nos tratamentos com 35% de sombreamento em comparação ao grupo dos flavonoides e capacidade antioxidante, o que foi demonstrado pela correlação do sombreamento com estes parametros. No método FRAP a maior correlação demonstra que o outono é a melhor época de colheita por apresentar maior concentração de compostos fitoquímicos. Ficou evidente a influência positiva dos sombreamentos (35 e 50% no teor de compostos fenólicos e flavonoides relacionados à capacidade antioxidante e à qualidade da erva-mate para atender ao mercado consumidor.

  10. Analisis experimental de la propagacion en redes de area corporal para la banda de ultra wideband. experimental characterization of the propagation in ultra wideband body area networks

    Science.gov (United States)

    Garcia Serna, Ruben Gregorio

    Diferentes dispositivos capaces de obtener informacion sobre parametros fisiologicos, cinematicos o contextuales del cuerpo pueden interconectarse de manera inalambrica dando lugar a las denominadas Redes de Area Corporal Inalambricas (WBAN, Wireless Body Area Networks). De entre las posibles tecnologias para establecer los enlaces, Ultra Wideband (UWB) esta captando cada vez un mayor interes debido a caracteristicas tales como el bajo nivel de potencia de transmision requerido (bajo nivel de exposicion a campos electromagneticos), el alto ancho de banda disponible y la alta resolucion temporal/espacial. El diseno de sistemas centrados en el cuerpo requiere de modelos de canal que describan de manera precisa la propagacion de senales en este tipo de entornos. Esta tesis se plantea con el objetivo de contribuir al estudio experimental de la propagacion en sistemas centrados en el cuerpo operando en la banda UWB. En primer lugar, se presenta un marco introductorio a las redes WBAN, sus elementos constitutivos, bandas de frecuencia, estandarizacion y modelos de canal. Ademas, se introducen los fundamentos de la tecnologia UWB y sus aplicaciones en este area. Seguidamente, se analiza en terminos de las perdidas de propagacion y la dispersion de retardo la propagacion en el canal off-body entre un transmisor fijo y un dispositivo receptor colocado sobre la superficie del cuerpo de un sujeto. Se considera la influencia de diferentes aspectos, tales como el entorno de medidas, la posicion de colocacion de una antena sobre el cuerpo y la postura adoptada por un sujeto. Finalmente, se analiza el canal de propagacion in-body considerando el movimiento relativo entre dos dispositivos causado por efecto de la respiracion. Las condiciones de propagacion en el interior del cuerpo se emulan por medio de un phantom liquido para UWB y la caracterizacion se plantea tanto en frecuencia, en terminos del modelado de la forma y el ensanchamiento del espectro Doppler, como en tiempo, por

  11. Kinetics of absorption of the environmental moisture in grainy materials

    Energy Technology Data Exchange (ETDEWEB)

    Villar-Cocina, E.; Valencia-Morales, E.; Gonzalez-Rodriguez, R. [Universidad Central de las Villas, Villaclara (Cuba)

    2001-02-01

    The moisture absorption in granulated materials used in foundry technologies is analyzed. The absorption process has a diffusive behavior mainly. A simple experimental technique, in which the wet weight increment was recorded as the experimental variable and an analytic method with computing procedure to find the parameters characterizing the process was used. The determination of these parameters by traditional methods is a very difficult task, very refined and expensive trials are needed. The fitting of the model permits to determine the diffusion coefficient and the moisture concentration in the separation surface between the sample and the environment. The concentration profiles are established for different times. Finally, the possibility of occurrence of superimposed diffusive processes in some materials is analyzed and the diffusion coefficient and the amount of moisture incorporated by each process are calculated. [Spanish] Se analiza la absorcion de humedad en materiales granulados utilizados en tecnologias de funcion cuyo proceso tiene un comportamiento difusivo principalmente. Se utiliza una tecnica experimental simple en la cual el incremento en peso humedo es registrado como variable experimental. Un metodo analitico con procesamiento computacional es usado para determinar los parametros que caracterizan el proceso, cuya determinacion por metodos tradicionales es dificil y requiere de ensayos muy refinados y costosos. El ajuste del modelo permite determinar el coeficiente de difusion y la concentracion de humedad en la superficie de separacion de la muestra y la atmosfera circundante. Se establecen los perfiles de concentraciones para diferentes instantes de tiempo. Finalmente, la posibilidad de ocurrencia de procesos difusivos superpuestos en algunos materiales es analizada y son calculados los coeficientes de difusion y la cantidad de humedad incorporada por cada proceso.

  12. Cleaning of contaminated grounds with hydrocarbons by means of biopile; Saneamiento de suelos contaminados con hidrocarburos mediante biopilas

    Energy Technology Data Exchange (ETDEWEB)

    Iturbe Arguelles, R.; Flores Torres, C.; Chavez Lopez, C.; Roldan Martin, A. [Instituto de Ingenieria, UNAM, Mexico, D.F. (Mexico)

    2002-03-01

    In 1999, the Instituto de Ingenieria of the Universidad Nacional Autonoma de Mexico (UNAM), initiated an evaluation through the soil and groundwater sampling and a risk health assessment in a Mexican refinery. An extended area was found contaminated with hydrocarbons. This area requires a soil remediation, taking into account that some zones present more than 30 000 mg/kg of Total Petroleum Hydrocarbons (TPH). Biopile system was recommended as the best remediation method to diminish TPH and some poliaromathic hydrocarbons (PAH). Therefore, an experimental biopile of 30 m{sup 3} was constructed with contaminated soil. After 22 weeks, results show more than 80% of TPH and PAH remove. [Spanish] El grupo de saneamiento de suelos y acuiferos del Instituto de Ingenieria de la Universidad Nacional Autonoma de Mexico (UNAM), inicio en 1999 la evaluacion de la contaminacion del subsuelo de una refineria en una zona costera del pais, mediante el muestreo de 325 puntos a 1.5 m de profundidad y con el analisis de los siguientes parametros: hidrocarburos totales del petroleo (HTP), hidrocarburos poliaromaticos (HAP), diesel, gasolina, metilterbutileter (MTBE) y los metales hierro, vanadio, zinc, cadmio, cromo y plomo. Asimismo, se llevo a cabo una evaluacion de riesgo a la salud a fin de determinar los niveles de limpieza de las areas contaminadas. Una vez realizado el estudio se propuso probar a nivel piloto dos tecnicas de saneamiento para las areas contaminadas con valores superiores a 30 000 mg/Kg de HTP, o bien, para las zonas en donde la evaluacion de riesgo a la salud indica la existencia de riesgo para uno o mas compuestos (Iturbe et al., 2000). Las tecnicas propuestas son biopilas y lavado de suelo con surfactantes. En este trabajo se presenta la prueba piloto con biopilas, de la cual se obtuvo una eficiencia de remocion de HTP del 80 porciento en cinco meses de operacion.

  13. Anaerobic/aerobic treatment for the waste water from the Instituto de Investigaciones Electricas installations; Tratamiento anaerobio-aerobio de las aguas residuales de las instalaciones del IIE

    Energy Technology Data Exchange (ETDEWEB)

    Arvizu Fernandez, Jose Luis [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    The waste water treatment plant of the Instituto de Investigaciones Electricas (IIE) is analyzed. This plant originally was a plant of the activated sludge type (aerobic development), process that consumes large amounts of energy and that produces residual sludge 5 or 6 times greater than the anaerobic processes. The methodology and the techniques utilized were base in the analysis of the existing plant introducing an anaerobic treatment and performing laboratory experimentation. The plant design parameters considered are described. The results show the benefits of treating by anaerobic means the waste waters since depuration are obtained on the order of 75%, as well as the reduction of resulting residual sludge and in energy consumption. A reduction of 60% to 70% can be attained if a combination of anaerobic and aerobic processes is utilized [Espanol] Se analiza la planta de tratamiento de aguas residuales del Instituto de Investigaciones Electricas (IIE). Esta planta era originalmente una planta de lodos activados (desarrollo aerobio), proceso que consume mucha energia y genera lodos residuales de 5 a 6 veces mas que los procesos anaerobios. La metodologia y las tecnicas utilizadas se basaron en el analisis de la planta de tratamiento existente en el IIE; en la caracterizacion residual del IIE; en la modificacion de la planta de tratamiento introduciendo un tratamiento anaerobio y efectuando experimentacion en laboratorio. Se describen los parametros de diseno de la planta considerados. Los resultados muestran los beneficios de tratar por medios anaerobios las aguas residuales ya que se obtienen depuraciones del orden del 75%, asi como la reduccion de lodos residuales resultantes y el consumo de energia, pueden reducirse de un 60% a un 70% si se utiliza la combinacion de los procesos anaerobios y aerobios

  14. El Boletín de la Sociedad Española de Cerámica y Vidrio en el S.C.I. Oportunidades y riesgos

    Directory of Open Access Journals (Sweden)

    Criado, E.

    2003-12-01

    Full Text Available A short description on the paramethers used by de the Institute for Scientific Information, particularly the Scientific Citation Index, as indicators of the qualitiy of the scientific journals was made. Some limitations to their use as global quality index was also indicated. The proccess issued by the Boletín de la Sociedad Española de Cerámica Y Vidrio to be included at the I.S.I and the positive evolution experimented was also described. Such change was inserted in the same positive tendency developped by the Spanish scientific journals, included in the Journal Citation Reports. Some suggestions to enhance the position of spanish journals was also incorporated.

    Se efectúa una somera descripción de los diferentes indicadores empleados por el Institute for Scientific Information( I.S.I y en particular del Scientific Citation Index utilizados como parametros para evaluar la calidad de las revistas científicas, así como las limitaciones que presentan como indicadores de la calidad global de una revista. Se describe el proceso seguido por el Boletín de la Sociedad Española de Cerámica y Vidrio para su inclusión en el citado indice, y la evolución positiva experimentada por el factor de impacto a lo largo de los años. Esta evolución se inscribe dentro de la mejora global de indicadores del aún muy reducido número de revistas españolas, 30, que incorpora el Journal Citation Records. Se señalan algunas sugerencias que permitan asentar y mejorar la visibilidad de las revista científicas españolas.

  15. UNA TECNICA ESTADISTICA PARA MEDIR LA CONFLICTIVIDAD SOCIAL A TRAVES DEL REGISTRO ARQUEOLOGICO (A Statistical Technique to Measure Social Conflict through the Archaeological Record

    Directory of Open Access Journals (Sweden)

    Pascual Izquierdo-Egea

    2015-03-01

    Full Text Available Se presenta aqui una tecnica estadistica para medir la conflictividad social a traves del registro mortuorio. Nace al amparo del metodo de valoracion contextual empleado en el analisis de los ajuares funerarios desde 1993. Se trata de una herramienta fundamental para el desarrollo de la arqueologia de los fenomenos sociales, cuyos relevantes resultados empiricos avalan su trascendencia teorica. Tras proceder a su conceptualizacion en funcion de la desigualdad social y la riqueza relativa, se explican las dos clases de conflictividad social definidas: estructural o estatica y coyuntural o dinamica. Finalmente, se incluyen sus conexiones con la ley demografica de Malthus a traves de sus dos parametros: poblacion y recursos. Todo este entramado teorico se ilustra con algunas aplicaciones referidas a las civilizaciones antiguas, abarcando la protohistoria iberica, la Mesoamerica prehispanica o la Roma altoimperial. ENGLISH: A statistical technique to measure social conflict through the mortuary record is presented here. It is born under the contextual valuation method used in the analysis of grave goods since 1993. This is a fundamental tool for the development of the archaeology of social phenomena, whose relevant empirical results support its theoretical significance. After conveying its conceptualization in terms of social inequality and relative wealth, the two classes of social conflict are explained: static or structural and dynamic or conjunctural. Finally, connections with the Malthusian demographic law through its two parameters—population and resources—are included. The synthesis of these theoretical frameworks is illustrated with applications to ancient civilizations, including Iberian protohistory, prehispanic Mesoamerica, and early imperial Rome.

  16. Numerical modeling of Etla Valley aquifer, Oax., Mexico: Evolution and remediation scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Flores-Marquez, E. L; Martinez-Serrano, R. G; Chavez, R. E; Crusillo, Y [Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Mexico D.F. (Mexico); Jimenez, G [Facultad de Ingenieria, Benemerita Universidad Autonoma de Puebla, Puebla (Mexico); Camops-Enriquez, O [Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Mexico D.F. (Mexico)

    2008-01-15

    Short-term evolution (for 2001, 2005 and 2015) for the shallow aquifer of Etla Valley, Oaxaca, southern Mexico, was simulated based in a 3D hydrological model elaborated from the available geological, geophysical, geochemical, and hydrologic parameters. The numerical simulations were based on Visual MODFLOW code. These simulations indicate that, if the actual extraction regime is maintained, the drawdown of the potentiometric surface will get worse to the SE of the study area (i. e. beneath Oaxaca city). The prevailing aquifer flow direction favors the ground water pollution by fertilizers and leakage from the sewage network (dumped to the Atoyac river). According to the numerical simulation, remediation of this situation is possible if the wells located in the neighborhood of Oaxaca City are relocated at the recharge zones (i. e. at the feet from Sierra de Juarez). This remediation scenario will allow a recovery of the drawdown of the potentiometric surface. [Spanish] Se presenta un modelo geohidrologico evolutivo 3D a corto plazo (para los anos 2001, 2005 y 2015) del acuifero somero del Valle de Etla, Oaxaca, sureste de Mexico, basado en los parametros disponibles de geologia, geofisica, geoquimica e hidrologia. Las simulaciones numericas fueron realizadas en Visual MODFLOW. Estas simulaciones indican que, si el actual regimen de extraccion es mantenido, el abatimiento de la superficie potenciometrica puede ser mayor en el SE del area de estudio (i. e. cerca de la ciudad de Oaxaca). La contaminacion por fertilizantes y por las fugas de drenaje es favorecida por la direccion de flujo imperante en el acuifero (vaciandose en el rio Atoyac). De acuerdo a las simulaciones numericas, existe una posible remediacion de este proceso, relocalizando los pozos situados en la ciudad de Oaxaca en las zonas de recarga (i. e. en las faldas de la Sierra de Juarez). Este escenario de remediacion permitiria una recuperacion en el nivel de la superficie potenciometrica.

  17. Influence of vegetation in the energetic balance outdoor urban spaces: Analysis and evaluation of its microclimatic effect; Influencia de la vegetacion en el balance energetico de los espacios exteriores urbanos: Analisis y evaluacion de sus efectos microclimaticos

    Energy Technology Data Exchange (ETDEWEB)

    Ochoa, J. Manuel [Universidad de Sonora, Hermosillo, Sonora (Mexico); Roset, Jaume [Universidad Politecnica de Cataluna, Barcelona (Spain)

    2000-07-01

    We present design guidelines to detect and to control the energy fluxes within and urban space. The main purpose is to create outdoor spaces with appropriate comfort conditions and to improve energy efficiency of adjacent buildings, by modifying its surrounding areas, approaching outdoor environment to the desired indoor conditions. The design guidelines as well as the concepts developed on this paper are explained in a language familiar to architects, urban planners and landscape designers, which have to take energetic and bioclimatic decisions up the first stage of a project process. A case study analysis of an urban scenery is presented, and conclusions about the advantage of using the vegetation as an instrument of microclimatic control are given. [Spanish] En este articulo se presentan pautas de diseno, que estan encaminadas, a saber detectar y en caso necesario reconducir, los flujos de energia dentro del espacio urbano. El proposito es crear espacios exteriores, con condiciones de confort ambiental, adecuadas a los usuarios de dicho espacio y por otro lado, mejorar la eficiencia energetica de los edificios, al modificar su entorno inmediato. Tanto las pautas de diseno, como los conceptos desarrollados en este trabajo, estan explicados con un discurso orientado al lenguaje de los profesionales dedicados al diseno urbano, arquitectonico y del paisaje, que son quienes deben hacer las consideraciones energeticas y bioclimaticas, desde las primeras etapas de un proyecto. Finalmente se presenta el ejemplo de un escenario urbano, donde se han realizado mediciones de los parametros climaticos, analizando cualitativa y cuantitativamente la influencia de la vegetacion y otros elementos del paisaje urbano sobre el microclima, y se dan conclusiones sobre la conveniencia de utilizar la vegetacion como un instrumento para el control microclimatico en los espacios exteriores urbanos.

  18. Use of correlation and linear regression to increase annual stream flow records; Uso de la correlacion y la regresion lineal para ampliar registros de volumenes escurridos anuales

    Energy Technology Data Exchange (ETDEWEB)

    Campos-Aranda, D.F. [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    1999-03-01

    Firstly, the estimates of standard deviation and arithmetic mean as basic statistical parameters are emphasised, which point out the variability and magnitude of annual streamflow records in the hydrological studies of planning water-resource developments inside a region. Then the equations for quantitative evaluations of statistical convenience of extending a short stream flow record are described in detail. The previous makes use of additional and common data in one or two closer hydrometric stations, with this the short observed record has a certain correlation (dependence or association). Later two numerical applications to real problems are given, the first one for the two dimensional model, which uses a closed hydrometric station in order to extend the short record, and the second application for the three dimensional model which makes use of two auxiliary hydrometric stations. Lastly, three general observations about the paper are cited. [Spanish] Inicialmente se destaca la importancia de las estimaciones de la medida y la desviacion estandar como parametros estadisticos basicos, los cuales caracterizan la magnitud y la variabilidad de los volumenes escurridos anuales en los estudios hidrologicos de planeacion del aprovechamiento de los recursos hidraulicos de una region. Enseguida, se describen con detalle las ecuaciones que permiten evaluar cuantitativamente si es conveniente o no, desde un punto de vista estadistico, ampliar el registro corto de escurrimientos, con base en datos comunes, adicionales y disponibles; esto en una o dos estaciones hidrometricas cercanas, con las cuales, el registro reducido guarda cierta correlacion (dependencia o asociacion). Lo anterior, significa evaluar si con base en el registro ampliado, las estimaciones de la medida y la variancia mejoran estadisticamente. Posteriormente, se realizan dos aplicaciones numericas a casos reales; una, para el modelo bidimensional que utiliza una estacion hidrometrica cercana para ampliar el

  19. Location and determination of steps of capacitors in shunt for distribution power lines; Localizacion y determinacion de pasos de capacitores en derivacion para lineas de distribucion

    Energy Technology Data Exchange (ETDEWEB)

    Pampin Vergara, Gabriela; Sarmiento Uruchurtu, Hector [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2001-07-01

    A methodology is presented to determine the optimal location of the capacitor banks in shunt for distribution networks. The proposed tool allows knowing the bank type to install (fixed, disconnect able or of pass), as well as the electrical parameters of the feeder and the economic benefit that the banks of capacitors represent, with a minimum of input data. Its development in a spreadsheet allows the analysis of numerous alternatives in an easy way. The method is based on that the structure of the feeders of distribution is, generally, of radial type, with which, and by means of an iterative process, the optimal location of the capacitor banks in shunt is looked for. The type of bank is determined based of the demand, as well as the number of steps. The results of the analysis in feeders of the network of the central area are shown. [Spanish] Se presenta una metodologia para determinar la localizacion optima de los bancos de capacitores en derivacion en redes de distribucion. La herramienta propuesta permite conocer el tipo de banco a instalar (fijo, desconcectable o de paso), asi como los parametros electricos del alimentador y el beneficio economico que representan los bancos de capacitores, con un minimo de datos de entrada. Su desarrollo en una hoja de calculo permite el analisis de numerosas alternativas de manera facil. El metodo se basa en que la estructura de los alimentadores de distribucion es, por lo general, de tipo radial, con lo cual, y por medio de un proceso iterativo, se busca la localizacion optima de los bancos de capacitores en derivacion. Se determina el tipo de banco en funcion de la demanda, asi como el numero de pasos. Se muestran resultados del analisis en alimentadores de la red del area central.

  20. Modal analysis applied to rotor balancing: two relevant technical aspects; Analisis modal aplicado al balanceo de rotores: dos aspectos tecnicos relevantes

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre Romano, Jorge E.; Preciado Delgado, Eduardo [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1991-12-31

    In applying the modal analysis to rotor balancing, it is frequent to find technical matters that are hardly developed in text books or that can only be deducted through a profound and complex study. For this reason, an engineer dedicated to the practice that wishes to deepen in the subject of rotor balancing, can hardly understand these matters, unless they are developed with the specific orientation that relate them with the balancing practice. In this paper two of these subjects related to the definition and recollection of modal parameters are presented: a) the fundamental form of the polar diagrams of response, that can be perfectly circular in certain cases and b) the relationship that exists among the modal forms of a rotor and the distribution of weights that must be placed to balance them in a given way. [Espanol] Al aplicar el analisis modal al balanceo de rotores, es frecuente encontrar temas tecnicos que dificilmente se desarrollan en los libros de texto, o que solo pueden deducirse mediante un estudio profundo y complejo. Por esta razon, un ingeniero dedicado a la practica que desee profundizar en el tema de balanceo de rotores, dificilmente podra comprender estos temas, a no ser que estos sean desarrollados con la orientacion especifica que los relacionen con la practica del balanceo. En este trabajo se presentan dos de esos temas relacionados con la definicion y obtencion de los parametros modales: a) la forma fundamental de los diagramas polares de respuesta, que puede ser circular perfecta en ciertos casos, y b) la relacion que existe entre las formas modales de un rotor y la distribucion de pesos que se deben colocar para balancear un modo dado.

  1. Development of an electro-thermal model for ZnO surge arrester under contamination; Desarrollo de un modelo electro-termico para apartarrayos de ZnO bajo contaminacion

    Energy Technology Data Exchange (ETDEWEB)

    Guardado Zavala, J.L.; Moreno Barraza, M.; Zazueta Pena, H.; Venegas Rebollar, V.; Melgoza Vazquez, E. [Instituto Tecnologico de Morelia, Morelia, Michoacan (Mexico)]. E-mail: lguarda@prodigy.net.mx; hzazuetapea@yahoo.com; vvenegas@yahoo.com; emelgoza@iimorelia.edu.mx

    2010-01-15

    An electro-thermal model for a Zinc Oxide (ZnO) surge arrester under contamination test is presented. The model is based in three sub-models: electrical, thermal and contamination, which interact in order to obtain the surge arrester performance under contamination tests. The electrical model is obtained from measurements and is based on a capacitance and a non-linear resistor. The thermal model takes into account the heat generated and dissipated by the column of varistors and its surroundings. The contamination is represented by dynamic impedance obtained from measurements in the arrester column during contamination tests. The full model is validated by calculating the temperature increase during contamination tests carried out in a two units ZnO surge arrester, class 190 kV. Finally, the results of the effect of several design and construction parameters in the voltage and temperature distribution in the arrester column during contamination tests are presented. [Spanish] Se presenta el modelo electro-termico para un apartarrayos de Oxido de Zinc (ZnO) durante pruebas de contaminacion. El modelo esta compuesto de tres sub-modelos: electrico, termico y de contaminacion, los cuales interactuan armonicamente para obtener el comportamiento del apartarrayos durante pruebas de contaminacion. El modelo electrico se obtiene de mediciones y esta compuesto de una capacitancia y una resistencia no-lineal. El modelo termico considera el calor generado y disipado en la columna de varistores y su entorno. La contaminacion se representa como una impedancia dinamica, cuyos valores se obtienen de mediciones en la columna del apartarrayos durante pruebas de contaminacion. El modelo se valida determinando el incremento de temperatura durante pruebas de contaminacion en un apartarrayos de ZnO de dos unidades clase 1990 kV. Finalmente, se presentan los resultados del impacto de diversos parametros de diseno y construccion en la distribucion de voltaje y temperatura en el apartarrayos

  2. The atomization and the flame structure in the combustion of residual fuel oils; La atomizacion y estructura de flama en la combustion de combustibles residuales

    Energy Technology Data Exchange (ETDEWEB)

    Bolado Estandia, Ramon [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1985-12-31

    In this article a research on the combustion of heavy residual fuel oils is presented. The type of flames studied were obtained by means of the burning of sprays produced by an atomizer designed and calibrated specially for the research purpose. The flame characteristics that were analyzed are its length, its luminosity, the temperature, the distribution of the droplets size and mainly the burning regime of the droplets in the flame. The experimental techniques that were used for these studies were shadow micro-photography, suction pyrometry and of total radiation, laser diffraction, 35 mm photography, and impact push. The analysis of the experimental results, together with the results of the application of a mathematical model, permitted to establish two parameters, that quantitatively related determine the burning regime of the droplets in a flame of sprays of residual heavy fuel oil. [Espanol] En este articulo se presenta una investigacion sobre la combustion de combustibles residuales pesados. El tipo de flamas estudiadas se obtuvieron mediante el quemado de sprays producidos por un atomizador disenado y calibrado especialmente para el proposito de la investigacion. Las caracteristicas de flama que se analizaron son la longitud, la luminosidad, la temperatura, la distribucion de tamano de gotas y, principalmente, el regimen de quemado de gotas en la flama. Las tecnicas experimentales que se usaron para estos estudios fueron microfotografia de sombras, pirometria de succion y de radiacion total, difraccion laser, fotografia de 35 mm y empuje de impacto. El analisis de resultados experimentales, junto con los resultados de la aplicacion de un modelo matematico, permitio establecer dos parametros, que relacionados cuantitativamente, determinan el regimen de quemado de gotas en una flama de sprays de combustible residual pesado.

  3. Method to allow the estimation of heat transfer coefficients in solar stills; Metodo para determinar coeficientes locales de transferencia de calor en destiladores solares

    Energy Technology Data Exchange (ETDEWEB)

    Rubio Cerda, Eduardo; Porta Gandara, Miguel A [CIBNOR, Mexico D.F (Mexico); Fernandez Zayas, Jose Luis [UNAM Mexico, D.F. (Mexico)

    2000-07-01

    This work reports an experimental method that allows to estimate the heat transfer coefficients in the neighborhood of walls or flat plates subject to convective transport phenomena. This method can be applied to a great variety of thermal systems since it is based on the knowledge of the border condition for the temperature at the surface of the plate, and the temperature profile that characterize the dimensionless coefficient of heat transfer in the fluid, according to its definition given by the Nusselt number. The approach of this work are the foundations of the method and the system that has been developed to apply it, that incorporates automatic acquisition equipment for continuos monitoring of the information and elements to control the parameters of interest. In addition, the experimental cavities on which the method will be evaluated are discussed, considering two different scales, as well as experiments in cavities filled with air, and with a mixture of air and steam water, as is the case for solar distillation. [Spanish] En este trabajo se presenta un metodo que permite determinar de manera experimental coeficientes de transferencia de calor por conveccion. Este metodo puede ser aplicado a una gran variedad de sistemas termicos ya que se fundamenta en el conocimiento de la condicion de frontera para la temperatura en la superficie de la placa, y del perfil de temperaturas que caracteriza el coeficiente adimensional de transferencia de calor en el fluido, de acuerdo a la definicion de este, dada por el numero de Nusselt. El trabajo que aqui se reporta esta enfocado a la fundamentacion del metodo y al equipamiento que se ha desarrollado para instrumentarlo, que incorpora equipos automaticos de adquisicion continua de informacion y elementos de control para los parametros de interes. Se presentan ademas, las cavidades experimentales sobre las que sera evaluado el metodo, que considera dos escalas diferentes, asi como experimentos en cavidades llenas de aire

  4. Energy analysis of the production process of sugar using modern technologies of process integration; Analisis energetico del proceso de produccion del azucar utilizando tecnicas modernas de integracion de proceso

    Energy Technology Data Exchange (ETDEWEB)

    Figueroa Ibarra, Luis; Arriola Medellin, Alejandro [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    1999-07-01

    The application of new concepts for the energy analysis of industrial processes, which consider the thermal integration of the process equipment, not only allows to detect energy recovery potentials that cannot be visualized with the traditional treatment of energy diagnosis of individual equipment, allows in addition, to suggest changes in the operation of the process that, without modifying the production, result in the reduction of the consumption of energy by the services and fuel. The analysis of thermal integration is illustrated for the case of a sugar mill, detecting a reduction potential in the use of fuel oil of 75%, and a potential increase of electrical production by cogeneration of 41%, departing from the modification of the use of the steam available in the process, and of the change of operation parameters of operation in the evaporation section. [Spanish] La aplicacion de nuevos conceptos para el analisis energetico de procesos industriales, los cuales consideran la integracion termica de los equipos del proceso, no unicamente permiten detectar potenciales de recuperacion de energia que no se pueden visualizar con el tratamiento tradicional de diagnostico energetico de equipos individuales, permiten ademas, sugerir cambios en la operacion del proceso que, sin modificar la produccion, redundan en una reduccion del consumo de servicios y combustible. El analisis de la integracion termica se ilustra para el caso de un ingenio azucarero, detectandose un potencial de reduccion del uso de combustoleo de 75%, y un potencial de incremento de produccion electrica por cogeneracion de 41%, a partir de la modificacion del uso del vapor disponible en el proceso, y del cambio de parametros de operacion en la seccion de evaporacion.

  5. Anaerobic/aerobic treatment for the waste water from the Instituto de Investigaciones Electricas installations; Tratamiento anaerobio-aerobio de las aguas residuales de las instalaciones del IIE

    Energy Technology Data Exchange (ETDEWEB)

    Arvizu Fernandez, Jose Luis [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1997-12-31

    The waste water treatment plant of the Instituto de Investigaciones Electricas (IIE) is analyzed. This plant originally was a plant of the activated sludge type (aerobic development), process that consumes large amounts of energy and that produces residual sludge 5 or 6 times greater than the anaerobic processes. The methodology and the techniques utilized were base in the analysis of the existing plant introducing an anaerobic treatment and performing laboratory experimentation. The plant design parameters considered are described. The results show the benefits of treating by anaerobic means the waste waters since depuration are obtained on the order of 75%, as well as the reduction of resulting residual sludge and in energy consumption. A reduction of 60% to 70% can be attained if a combination of anaerobic and aerobic processes is utilized [Espanol] Se analiza la planta de tratamiento de aguas residuales del Instituto de Investigaciones Electricas (IIE). Esta planta era originalmente una planta de lodos activados (desarrollo aerobio), proceso que consume mucha energia y genera lodos residuales de 5 a 6 veces mas que los procesos anaerobios. La metodologia y las tecnicas utilizadas se basaron en el analisis de la planta de tratamiento existente en el IIE; en la caracterizacion residual del IIE; en la modificacion de la planta de tratamiento introduciendo un tratamiento anaerobio y efectuando experimentacion en laboratorio. Se describen los parametros de diseno de la planta considerados. Los resultados muestran los beneficios de tratar por medios anaerobios las aguas residuales ya que se obtienen depuraciones del orden del 75%, asi como la reduccion de lodos residuales resultantes y el consumo de energia, pueden reducirse de un 60% a un 70% si se utiliza la combinacion de los procesos anaerobios y aerobios

  6. Technical-economic study of energy efficiency in offshore industrial electrical systems; Estudio tecnico economico de eficiencia energetica en sistemas electricos industriales costa afuera

    Energy Technology Data Exchange (ETDEWEB)

    Fiscal Escalante, Raul [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    2001-07-01

    In this work the methodology of analysis and the results obtained are presented in an technical-economic study for the application of power efficiency measures for a marine platform. The methodology is considered in the following steps: 1) Technical evaluation of the installation 2) Technical analyses of the optimization alternatives 3) Economic evaluation of the selected optimization alternatives graphs of the thermal regime of the variation with respect to the generation, variation of the efficiency with respect to the generation, efficiency curve of the motor and the designed curve of the pump are presented. A table of general reference parameters and another one of particular reference is given. Also a table of the economic evaluation when changing the electrical motor by one more efficient is presented. It is concluded that a potential of energy saving exists in their processes, generating an opportunity to perform a technical-economic feasibility study in these facilities. [Spanish] En este trabajo se presenta la metodologia de analisis y los resultados obtenidos en un estudio tecnico-economico para la aplicacion de medidas de eficiencia energetica para una plataforma marina. Se plantea la metodologia en los siguientes pasos: 1) Evaluacion tecnica de la instalacion 2) Analisis tecnico de las alternativas de optimizacion 3) Evaluacion economica de las alternativas de optimizacion seleccionadas. Se muestran graficas de la variacion del regimen termico respecto a la generacion, variacion de la eficiencia respecto a la generacion, curva de eficiencia del motor y curva de diseno de la bomba. Se da una tabla de parametros de referencia generales y otra de referencia particulares. Tambien se presenta una tabla de la evaluacion economica al cambiar el motor electrico por uno mas eficiente. Se concluye que existe un potencial de ahorro de energia en sus procesos, generando una oportunidad para realizar estudios de factibilidad tecnica economica en dichas instalaciones.

  7. EFECTO NEFROPROTECTOR DEL ÁCIDO ASCÓRBICO EN UN MODELO DE DAÑO RENAL INDUCIDO POR GENTAMICINA EN CONEJOS

    Directory of Open Access Journals (Sweden)

    Javier Antonio Padilla Funes

    2013-08-01

    Full Text Available Objetivo. Uno de los efectos secundarios mas notables de la Gentamicina es su nefrotoxicidad. En este estudio se propone el posible efecto nefroprotector del acido ascorbico como barredor de radicales libres de oxigeno. Metodología. Se ejecuto un estudio experimental en 24 conejos machos, raza Nueva Zelanda, cuyo peso fue de 1,5 +/- 0,5 Kg. Los sujetos experimentales fueron distribuidos en tres grupos. El grupo Control se manejo con Gentamicina a dosis de 80 mg/Kg/dia por via IM. El grupo Acido Ascorbico se trato a dosis de 200 mg/kg/dia via IP y Gentamicina 80mg/Kg/dia IM. El grupo Sham se manejo con SSN 0,9% por via IP e IM, durante cinco dias consecutivos, para cada grupo. Se determinaron los siguientes parametros: creatinina serica, N-Acetil s-D glucosaminidasa urinaria (NAG-U, diuresis e histopatologia de las muestras renales. Resultados. La creatinina serica fue significativamente mayor para el grupo Control respecto al grupo Acido Ascorbico (p<0,05. Respecto a la diuresis, se observo una tendencia a la poliuria en el grupo Control. En cuanto a NAG-U, se observo inhibicion completa de la actividad enzimatica en el grupo Acido Ascorbico. El analisis histopatologico demuestra hallazgos de necrosis tubular aguda en el 100% del grupo control, mientras que en el grupo Acido Ascorbico se obtuvo en un 50% de los sujetos unicamente detritos intraluminales. Conclusiones. La administracion concomitante de Acido Ascorbico con Gentamicina, disminuye significativamente el dano tubular renal, evidenciado en los valores de creatinina serica, NAG, diuresis e histopatologia renal.

  8. Effect on the performance with the washing of the gas turbines Ruston TB5000 with a system of washing out of line in high contamination conditions; Efecto en el rendimiento con el lavado de las turbinas de gas Ruston TB5000 con un sistema de lavado fuera de linea en condiciones de alta contaminacion

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Diaz, Carlos Rodolfo; Aboites Davila, Fernando [CIATEQ, A.C., Queretaro (Mexico); Rocha Orozco, Moises [PEMEX Refinacion, Mexico, D.F. (Mexico)

    2007-11-15

    This paper shows the effects on the gas turbine performance with a washing system out of line, based on liquid detergent and water for the case of 2 Ruston TB5000 gas turbines located in conditions of high contamination in the atmosphere such as ashes, high humidity and temperature. The investigation was realized making periodical measurements of the main parameters of the turbo-pump during 1 year of operation with load conditions without stopping of about 125 mbpd (million of barrels per day) of gas LP. This article suggests how the low performance of the turbines in a hostile atmosphere can be improved and which could be the limitations of the washing systems based on liquid detergents. The data of the washing sessions were collected during a year and studied under statistical methods creating performance curves and comparing them with curves of other machines being washed with other washing systems. [Spanish] Este trabajo muestra los efectos en el rendimiento de la turbina de gas con un sistema de lavado fuera de linea, basado en detergente liquido y agua para el caso de 2 turbinas de gas Ruston TB5000 localizados en condiciones de alta contaminacion en el ambiente como cenizas, alta humedad y temperatura. La investigacion fue realizada haciendo mediciones periodicas de los parametros principales de turbo bomba durante 1 ano de operacion con condiciones de carga sin parar de alrededor de 125 mbpd (millones de barriles por dia) de gas LP. Este articulo sugiere como se puede mejorar el bajo desempeno de las turbinas en un ambiente hostil y cuales podrian ser las limitaciones de los sistemas de lavado basados en detergentes liquidos. Los datos de las sesiones de lavado fueron recolectados durante un ano y estudiados bajo metodos estadisticos creando curvas de rendimiento y comparandolas con curvas de otras maquinas siendo lavadas con otros sistemas de lavado.

  9. La decisione Holt v. Hobbs: una svolta nelle politiche di religious accommodation con riguardo agli istituti di detenzione nell’ordinamento statunitense?

    Directory of Open Access Journals (Sweden)

    Adelaide Madera

    2016-11-01

    SOMMARIO: 1. La libertà religiosa negli istituti di detenzione negli U.S.A. e il caso Holt v. Hobbs – 2. Le esigenze di bilanciamento fra libertà religiosa ed esigenze di ordine e sicurezza nelle istituzioni penitenziarie – 3. La diluizione delle forme di tutela della libertà religiosa nel contesto degli istituti di detenzione – 4. L’impatto del R.F.R.A. sulla tutela della libertà religiosa negli istituti di detenzione – 5. L’adozione del R.L.U.I.P.A. – 6. Il riconoscimento di legittimità del R.L.U.I.P.A. alla luce dell’Establishment Clause – 7. I nodi irrisolti del caso Cutter v. Wilkinson – 8. Le interferenze del Prison Litigation Reform Actsulla tutela dell’esercizio della libertà religiosa dei detenuti – 9. La frammentazione dei parametri adoperati dai diversi circuiti d’appello – 10. La decisione Holt v. Hobbs – 11. Le motivazioni della Corte – 12. Il (parziale ridimensionamento del parametro della due deference – 13. La tutela estensiva della libertà religiosa promossa dalla Corte Roberts – 14. Holt e Hobby Lobby a confronto – 15. Il crescente rilievo assunto dall’elemento dei third-party burdens nella giurisprudenza della Corte – 16. Annotazioni conclusive.

  10. Modal analysis applied to rotor balancing: two relevant technical aspects; Analisis modal aplicado al balanceo de rotores: dos aspectos tecnicos relevantes

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre Romano, Jorge E; Preciado Delgado, Eduardo [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1992-12-31

    In applying the modal analysis to rotor balancing, it is frequent to find technical matters that are hardly developed in text books or that can only be deducted through a profound and complex study. For this reason, an engineer dedicated to the practice that wishes to deepen in the subject of rotor balancing, can hardly understand these matters, unless they are developed with the specific orientation that relate them with the balancing practice. In this paper two of these subjects related to the definition and recollection of modal parameters are presented: a) the fundamental form of the polar diagrams of response, that can be perfectly circular in certain cases and b) the relationship that exists among the modal forms of a rotor and the distribution of weights that must be placed to balance them in a given way. [Espanol] Al aplicar el analisis modal al balanceo de rotores, es frecuente encontrar temas tecnicos que dificilmente se desarrollan en los libros de texto, o que solo pueden deducirse mediante un estudio profundo y complejo. Por esta razon, un ingeniero dedicado a la practica que desee profundizar en el tema de balanceo de rotores, dificilmente podra comprender estos temas, a no ser que estos sean desarrollados con la orientacion especifica que los relacionen con la practica del balanceo. En este trabajo se presentan dos de esos temas relacionados con la definicion y obtencion de los parametros modales: a) la forma fundamental de los diagramas polares de respuesta, que puede ser circular perfecta en ciertos casos, y b) la relacion que existe entre las formas modales de un rotor y la distribucion de pesos que se deben colocar para balancear un modo dado.

  11. Performance optimization methodology in a Francis turbine vacuum cleaner based on the modification of the boundary conditions; Metodologia de optimizacion del rendimiento en un aspirador de turbina Francis en base a la modificacion de las condiciones de frontera

    Energy Technology Data Exchange (ETDEWEB)

    Galvan Gonzalez, S.; Rubio Maya, C.; Mendoza Covarrubias, C. [Universidad Michoacana de San Nicolas Hidalgo, Morelia, Michoacan (Mexico)]. E-mail: srgalvan@umich.mx; crmaya@umich.mx; cmendoza@umich.mx; Pacheco Ibarra, J.; Martinez Patino, J. [Universidad de Guanajuato, Salamanca, Guanajuato (Mexico)

    2010-11-15

    This paper focus on establishing an optimization methodology for maximizing the draft tube performance as a function of the inlet velocity profile. The overall work is defined by four steps: the inlet velocity profile parametrization, the numerical optimization set-up, the numerical computational fluid dynamics (CFD) draft tube model and the objective function definition. However as the inlet velocity profile is a new challenge, each step of the parametrization must be properly validated. In the first step, a suitable parametrization with an appropriate number of variables is chosen to approximate an experimental draft tube inlet velocity profile. The second step considers the reduction of the actual numerical model to develop the CFD calculations. In the third step, the optimization algorithm set-up is specified. Finally, the objective function is evaluated. As each step is properly validated, it is considered this proved methodology will help to find an inlet velocity profile shape which will be able to suppress or mitigate the undesirable draft tube flow characteristics. [Spanish] Este documento se enfoca en establecer una metodologia de optimizacion para maximizar el rendimiento del tubo de aspiracion en funcion de las condiciones de frontera del aspirador. El metodo es definido en cuatro etapas: la parametrizacion del perfil de velocidades, la evaluacion del algoritmo de optimizacion, la valoracion de la funcion objetivo y la validacion del modelo numerico. La parametrizacion se realiza con un numero de variables apropiado para aproximar el perfil de velocidades experimental. El segundo paso considera establecer los parametros del algoritmo de optimizacion, la funcion objetivo es obtenida mediante un estudio de sensibilidad y el modelo numerico es validado y reducido en la cantidad de elementos para adecuarlo al proceso de optimizacion. Se considera que esta metodologia ayudara a encontrar un perfil de velocidad de entrada el cual reduzca las perdidas de

  12. Attenuation of Ultraviolet Radiation by Dust in Interstellar Clouds

    Science.gov (United States)

    Escalante, V.

    1994-07-01

    Se han obtenido soluciones de la ecuación de transporte para la dispersión coherente, no conservativa y anisotrópica para estimar la precisión de métodos aproximados, usados en modelos de nubes en que la luz es atenuada principalmente por el polvo. En los cálculos se ha aplicado el metodo de armónicos esféricos para distintos parámetros del polvo. Se ha explorado la posibilidad de descubrir cambios en las caracterísiticas del polvo mediante observaciones de regiones fotodisociadas. Se muestra que para altos valores del albedo de dispersión simple y del parametro de asimetria de Ia función de fase que son adecuados para el polvo galáctico, no es posible determinar variaciones de más de un factor de 2 en el cociente de gas a polvo. Solutions to the transfer equation for coherent, non-conservative, anisotropic scattering have been obtained in order to estimate the accuracy of approximate methods used in models of clouds where light is attenuated mostly by dust. In the calculations the spherical harmonic method has been applied for different grain parameters. The possibility of discovering changes of dust characteristics through observations of photodissociation regions has been considered. It is shown that for the high values of the single scattering albedo and the asymmetry parameter of the phase function for redistribution that appear to be appropriate for galactic dust, it is not possible to determine variations of more than a factor of 2 in the gas to dust ratio.

  13. Operational performance of the Avispa-IIE wind generator in microhybrid systems

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Galarza, Raul; Mejia Neri, Fortino [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1998-12-31

    The purpose of this paper is to make a general analysis over the operational performance of the Avispa-IIE wind generator in an Solar-Eolic hybrid installation, at an eco-tourist resort. This work was performed through the monitor of the wind generator and the system itself throughout a year, for the acquisition taking the variables of interest and operational parameters that might allow to characterize and to evaluate the general behavior of the system. Herein are the principals characteristics of the wind generator; its performance curve, the basic configuration of the installation and the control philosophy; Likewise, some technical and human problems which arise during the operation of the system are included, the implementation of improvements in the wind generator and the general results acquired during the time of operation of the wind generator in the cited installations. [Espanol] El proposito de este articulo es el hacer un analisis general del comportamiento operacional del aerogenerador Avispa-IIE en una instalacion hibrida Solar-Eolica en un lugar de veraneo eco-turistico. Este trabajo ha sido llevado a cabo mediante el monitor del aerogenerador y el sistema mismo por espacio de un ano, para la adquisicion de las variables de interes y de los parametros operacionales que pudieran servir para caracterizar y evaluar el comportamiento general del sistema. Aqui se incluyen las caracteristicas principales del aerogenerador; su curva de comportamiento, la configuracion basica de la instalacion y la filosofia del control. De la misma manera se incluyen algunos problemas tecnicos y humanos que se originan durante la operacion del sistema y la puesta en practica de las mejoras del aerogenerador y los resultados generales adquiridos durante el tiempo de operacion del aerogenerador en las instalaciones citadas.

  14. Estudo comparativo entre estrelas centrais de nebulosas planetárias deficientes em hidrogênio

    Science.gov (United States)

    Marcolino, W. L. F.; de Araújo, F. X.

    2003-08-01

    Apresentamos neste trabalho o resultado de um estudo das principais características espectrais das estrelas centrais de nebulosas planetárias (ECNP) deficientes em hidrogênio. A origem e a evolução dessas estrelas ainda constitui um problema em aberto na evolução estelar. Geralmente esses objetos são divididos em [WCE], [WCL] e [WELS]. Os tipos [WCE] e [WCL] apresentam um espectro típico de uma estrela Wolf-Rayet carbonada de população I e as [WELS] apresentam linhas fracas de carbono e oxigênio em emissão. Existem evidências que apontam a seguinte sequência evolutiva : [WCL] = > [WCE] = > [WELS] = > PG 1159 (pré anã-branca). No entanto, tal cenário apresenta falhas como por exemplo a falta de ECNP entre os tipos [WCL] e [WCE]. Baseados em uma amostra de 24 objetos obtida no telescópio de 1.52m em La Silla, Chile (acordo ESO/ON), ao longo do ano 2000, apresentamos os resultados da comparação das larguras equivalentes de diversas linhas relevantes entre os tipos [WCL], [WCE] e [WELS]. Verificamos que nossos dados estão de acordo com a sequência evolutiva. Baseado nas linhas de C IV, conseguimos dividir pela primeira vez as [WELS] em dois grupos principais. Além disso, os dados reforçam a afirmação de que as [WCE] são as estrelas que possuem a maior temperatura entre as ECNP deficientes em hidrogênio. Discutimos ainda, a escassez de dados disponíveis na literatura e a necessidade da obtenção de parametros físicos para estes objetos.

  15. Mineral-deposit model for lithium-cesium-tantalum pegmatites

    Science.gov (United States)

    Bradley, Dwight C.; McCauley, Andrew D.; Stillings, Lisa L.

    2017-06-20

    Lithium-cesium-tantalum (LCT) pegmatites comprise a compositionally defined subset of granitic pegmatites. The major minerals are quartz, potassium feldspar, albite, and muscovite; typical accessory minerals include biotite, garnet, tourmaline, and apatite. The principal lithium ore minerals are spodumene, petalite, and lepidolite; cesium mostly comes from pollucite; and tantalum mostly comes from columbite-tantalite. Tin ore as cassiterite and beryllium ore as beryl also occur in LCT pegmatites, as do a number of gemstones and high-value museum specimens of rare minerals. Individual crystals in LCT pegmatites can be enormous: the largest spodumene was 14 meters long, the largest beryl was 18 meters long, and the largest potassium feldspar was 49 meters long.Lithium-cesium-tantalum pegmatites account for about one-fourth of the world’s lithium production, most of the tantalum production, and all of the cesium production. Giant deposits include Tanco in Canada, Greenbushes in Australia, and Bikita in Zimbabwe. The largest lithium pegmatite in the United States, at King’s Mountain, North Carolina, is no longer being mined although large reserves of lithium remain. Depending on size and attitude of the pegmatite, a variety of mining techniques are used, including artisanal surface mining, open-pit surface mining, small underground workings, and large underground operations using room-and-pillar design. In favorable circumstances, what would otherwise be gangue minerals (quartz, potassium feldspar, albite, and muscovite) can be mined along with lithium and (or) tantalum as coproducts.Most LCT pegmatites are hosted in metamorphosed supracrustal rocks in the upper greenschist to lower amphibolite facies. Lithium-cesium-tantalum pegmatite intrusions generally are emplaced late during orogeny, with emplacement being controlled by pre-existing structures. Typically, they crop out near evolved, peraluminous granites and leucogranites from which they are inferred to be

  16. Microbiological quality in the Zacatepec's aquifer, Morelos, Mexico; Calidad microbiologica del acuifero de Zacatepec, Morelos, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, Elizabeth; Robles, Esperanza; Sainz, Ma. Guadalupe; Ayala, Reynaldo; Campoy, Emelia [Facultad de Estudios Superiores, Iztacala, Universidad Nacional Autonoma de Mexico, Tlalnepantla, Estado de Mexico (Mexico)]. E-mail: erf@servidor.unam.mx

    2009-11-15

    .3, temperature was in a range of 25.1 to 28 degrees Celsius and dissolved oxygen of 2.9 to 4.8 mg/L. The average values of the physicochemical parameters among the wells were very similar. The presence of coliforms indicates human pollution in the aquifer, and together with the presence of pathogenic free-living amoebae, stand out the significance of water disinfection before it being used as drinking water. [Spanish] Los mantos subterraneos constituyen una de las principales fuentes de abastecimiento de agua potable en Mexico. Por lo general, albergan solo a ciertos organismos debido a su bajo contenido en materias nutritivas. Sin embargo, las actividades humanas y el crecimiento urbano son los principales factores para la contaminacion de los acuiferos. De esta forma, el agua puede contener contaminantes quimicos o biologicos que causan diversas enfermedades, entre los que estan algunas amibas de vida libre (AVL). El objetivo de este estudio es determinar la calidad microbiologica (coliformes totales, coliformes fecales y amibas de vida libre) del acuifero de Zacatepec, Morelos. Para ello se realizaron muestreos mensuales durante un ano en trece pozos del acuifero; se midieron en el lugar los siguientes parametros fisicoquimicos: pH, oxigeno disuelto y temperatura. Se determinaron los coliformes totales y fecales utilizando la tecnica de filtro de membrana; para las amibas se utilizo el medio selectivo agar no nutritivo con Enterobacter aerogenes (NNE) y la identificacion se realizo tomando en cuenta sus caracteristicas morfologicas. Todos los pozos presentaron contaminacion por coliformes totales, uno de ellos con una media geometrica de 107 UFC/100 mL. En cambio, los coliformes fecales estuvieron ausentes en cuatro de los pozos, pero en uno se presento contaminacion alta con una media geometrica de 107 UFC/100 mL. El pozo mas contaminado con bacterias fue el numero 3 y la contaminacion de coliformes totales y fecales mas alta se presento en los meses de abril y julio. Se

  17. Co-generation system with integrated functions of active filter; Sistema de cogeneracion con funciones de filtro activo integradas

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez Grajales, Humberto Raul

    2002-07-15

    adaptive interference. This technique maintains the system in the best functional state, by means of continuous self adjustment facing changes in the operation parameters, generating important and satisfactory results. In addition, simultaneously the PVS uses, in the pursuit of the point of maximum power, the technique of {sup d}isturb and observe{sup ,} which offers a high performance in the injection of active power. [Spanish] Sin duda, la energia electrica es la forma de energia mas ampliamente usada en las actividades economicas y sociales de nuestro mundo moderno. Por ello, se puede decir que las companias generadoras y distribuidoras de electricidad asumen dos retos de relevante preocupacion actual. Uno es generar con mayor eficiencia, menor costo y con un minimo impacto sobre el medio ambiente. El segundo es cumplir con la calidad del suministro, que ha llegado a ser un punto importante tanto para los usuarios como para las companias que distribuyen la energia electrica, y que se refleja en una distribucion y un consumo de energia mas eficiente. El trabajo de tesis que se presenta, describe un sistema fotovoltaico (SFV) interconectado a la red electrica que ayuda a superar los retos citados. Este SFV tiene la funcion de recibir la energia solar entregada por un arreglo de celdas FV; operar en el punto maximo de potencia de las celdas (para mayor aprovechamiento de la energia captada); acondicionarla a una senal alterna, dentro de los parametros tecnicos normativos para la interconexion electrica (establecidos por la compania; Comision Federal de Electricidad en Mexico); e inyectarla a la red electrica con el proposito de compensar potencia reactiva (filtrado activo) demandada por cargas lineales y no lineales, reduciendo la contaminacion de la red electrica; ademas de compensar potencia activa en los picos de demanda de energia electrica maxima. El sistema funciona como filtro activo durante todo el dia, lo que permite que la capacidad de potencia instalada por el

  18. Problems raised by pulse analysers - functional multi-dimensional analysers; Problemes poses par les analyseurs en impulsions - Analyseurs multidimensionnels fonctionnels; Problemy, voznikayushchie v svyazi s ispol'zovaniem analizatorov impul'sov - funktsional'nye mnogorazmernye analizatory; Problemas planteados por los analizadores de impulsos - Analizadores multidimensionales funcionales

    Energy Technology Data Exchange (ETDEWEB)

    Pages, A [Centre d' Etudes Nucleaires de Saclay (France)

    1962-04-15

    de nombreuses raisons: le nombre de parametres possibles est beaucoup trop reduit (deblocage seulement sur les analyseurs 100 et 256 canaux) ainsi que leur capacite; cette limitation multiplie considerablement le temps d'accelerateur; parfois l'experience est rendue impossible par le mauvais de ces analyseurs; par ailleurs, etant concus en un seul , ils manquent de d'utilisation. Un appareil multidimensionnel limite a 2 voies de 63 canaux a ete etudie et construit en 1958-59. Une separation est faite entre les differentes fonctions essentielles: analyse, transfert (fonctionnement en multidimensionnel) et exploitation des resultats. MM. Amram, Guillon et Thenard etudient et construisent a la SEG un analyseur multidimensionnel 1023 canaux x 63 canaux (destine au groupe de mesures de vitesses de neutrons de la SPNBE). Par ailleurs, afin de repondre aux limitations precedemment formulees, le laboratoire d'electronique de la SPNBE realise un analyseur multidimensionnel fonctionnel, ou la fonction de transfert a ete elle-meme decomposee en unites (rythmeur, memoire non integratrice, conditionneur et calculateur). Les types d'unites choisies sont, comme les limites definissant les voies, variables en fonction des besoins et de la complexite de l'experience (langage standard interfonctionnel). (author) [Spanish] Los investigadores emplean cada vez con mayor frecuencia conjuntos analizadores que permiten obtener una funcion de varios parametros (el numero de parametros y la precision relativa de cada uno de ellos puede variar de un experimento a otro). Por muchas razones, los analizadores actuales no se prestan bien para los experimentos, que son cada dia mas complejos: el numero de parametros posibles es excesivamente pequeno (desbloqueo solo en los analizadores de 100 y 256 canales) y tambien lo es su capacidad; esta limitacion multiplica considerablemente el tiempo de acelerador. Algunas veces, el bajo ''rendimiento'' de estos analizadores

  19. Radioactive apparatus for measuring the thickness of hot sheet-metal; Jauge d'epaisseur radioactive pour la mesure a chaud de plaques metalliques; Radioaktivnyj izmeritel' tolshchiny goryachego listovogo prokata; Calibrador radiactivo para la medicion en caliente de chapas

    Energy Technology Data Exchange (ETDEWEB)

    Vasichev, B N; Latyshev, V K; Pliskin, Yu S; Felinger, A K

    1962-01-15

    exposent le plan fondamental de l'appareil permettant de controler l'epaisseur des feuilles au cours du laminage et examinent les facteurs dont depend la precision de la mesure a chaud de l'epaisseur des feuilles (temperature, ondulation, humidite superficielle, composition de la feuille et sa position sur le train de laminoirs). Ils decrivent egalement la construction d'un prototype a usage industriel pour me gamme d'epaisseurs allant de 14 a 44 mm. Les essais industriels faits avec l'appareil ont montre que, lors de l'emploi d'une source au {sup 137}Cs d'une activite equivalente a celle de 9,2 g de radium, la precision de la mesure a chaud de l'epaisseur des feuilles dans la gamme susmentionnee est de {+-} 0,1 mm. L'appareil effectue une mesure par seconde. Il fonctionne de facon satisfaisante eu egard aux conditions dans lesquelles il est utilise. (author) [Spanish] Para obtener una elevada exactitud en las condiciones de funcionamiento del tren de laminado se escogio un metodo dinamico en el que el parametro testigo barre todos los valores del intervalo a medir, en tanto que la componente cero indica solamente el momento en que el parametro medido y el parametro testigo son iguales. Este metodo elimina las retroacciones mecanicas y los desplazamientos variables del metodo de compensacion estatica, permite alcanzar la exactitud deseada y funciona con rapidez suficiente en las complejas condiciones del laminado. La memoria describe las caracteristicas fundamentales del aparato para comprobar el espesor de las chapas durante el laminado, y discute los factores que influyen en la exactitud de la medicion del espesor de chapas en caliente (temperatura, ondulacion, humedad superficial y composicion de la chapa, y su posicion en el tren de laminado). Describe tambien la construccion de un aparato experimental para la industria, destinado a medir espesores comprendidos entre 14 y 44 mm. Los ensayos industriales realizados con este aparato indican que con una fuente de {sup 137

  20. Advanced epithermal thorium reactor (AETR) physics; Physique d'un reacteur au thorium, a neutrons epithermiques, de type perfectionne (AETR); Fizika usovershenstvovannog o nadteplovogo torievogo reaktora; Fisica del reactor epitermico de tipo avanzado, alimentado con torio (AETR)

    Energy Technology Data Exchange (ETDEWEB)

    Campise, A. V. [Atomics International, Canoga Park, CA (United States)

    1962-03-15

    'etude de cet ensemble a mis en relief l'importance des donnees relatives aux sections efficaces et de l'interpretation theorique des resultats experimentaux pour l'etude d'un reacteur au thorium de type perfectionne. La precision des methodes analytiques employees a ete demontree lors de l'analyse des resultats experimentaux obtenus avec le ZPR-III. L'auteur compare trois configurations pour le transfert de chaleur, en utilisant le temps de doublement comme parametre d'optimisation. Les effets de la production de {sup 233}Pa et d'isotopes de l'uranium sur le bilan neutronique, les taux possibles de surgeneration et les caracteristiques de la combustion sont evalues en tenant compte de l'imprecision des sections efficaces nucleaires. (author) [Spanish] El autor estudia la concepcion del reactor AETR desde el punto de vista de la teoria actual de los parametros nucleares y del balance neutronico. En los sistemas moderados por grafito examina el efecto de la captura por resonancia en el torio para energias medias de absorcion del orden de 0,10 a 100 keV. Aplica formulas de resonancia angosta y de resonancia ancha para obtener la integral de resonancia efectiva en funcion de la temperatura, correspondiente a las barras de torio, y dicho parametro se expresa como secciones eficaces equivalentes de varios grupos. Se ha disenado y construido un conjunto critico para obtener datos nucleares indispensables en la gama de energias intermedias. En el diseno nuclear de dicho conjunto, se ha tenido particularmente en cuenta la importancia de los datos relativos a secciones eficaces y la interpretacion teorica de estos resultados experimentales, cosas ambas relacionadas con el diseno del reactor AETR. La precision de los metodos analiticos ha quedado demostrada por el estudio de los resultados experimentales obtenidos con el reactor ZPR-III. Se comparan tres sistemas de transmision de calor utilizando el tiempo de duplicacion como parametro optimo. Se estudia el efecto de la formacion

  1. Data Evaluation Problems in the Pulsed Neutron Source Method; Problemes d'Evaluation des Donnees dans les Applications de la Methode de la Source Pulsee; Problemy otsenki dannykh pri primenenii metoda istochnika impul'snykh nejtronov; Problemas de Evaluacion de Datos en el Metodo de la Fuente de Neutrones Pulsados

    Energy Technology Data Exchange (ETDEWEB)

    Pal, L.; Bod, L.; Szatmary, Z. [Central Research Institute for Physics, Hungarian Academy of Sciences, Budapest (Hungary)

    1965-08-15

    moyen de transport dans de nombreuses matieres hydrogenees. (author) [Spanish] Desde hace mas de diez anos se viene empleando el metodo de los neutrones pulsados para determinar los parametros de difusion de los neutrones termicos. Este metodo ha resultado especialmente idoneo para el estudio de los moderadores hidrogenados. Los autores dan los resultados de las mediciones hechas en agua, benceno, tolueno, xileno, ciclohexano, n-hexano y difenilo, y examinan los metodos para evaluar con el minimo error los parametros de difusion de interes partiendo de los datos obtenidos en las mediciones. Se examina detenidamente, tanto en el plano teorico como en el experimental, el efecto de tiempo de vuelo que se manifiesta por razones tecnicas cuando se investigan moderadores a elevadas temperaturas, y que influye en el valor de la constante de desintegracion, y se exponen las condiciones geometricas en que se ha de operar para obtener resultados satisfactorios. Los autores determinan tambien el efecto que sobre la constante de desintegracion ejerce el tiempo muerto del detector neutronico y del amplificador, y demuestran que es despreciable cuando [i(t) {tau}]{sup 2} << 1, siendo i/t/dt el numero de neutrones detectados en el intervalo de tiempo/t, t + dt/, y {tau} el tiempo muerto. Se evaluo la constante de desintegracion empleando el metodo de la maxima probabilidad. Para determinar inequivocamente la funcion de probabilidad, se eligio un analizador multicanal que acumulaba como maximo una sola senal por ciclo de analisis y por canal. Se comprobo que la incorporacion del parametro caracteristico del fondo a la funcion de probabilidad tiene primordial importancia. Los parametros de la funcion de maxima probabilidad se evaluaron en una calculadora aplicando el metodo de iteracion de Newton. Cuando no se tiene debidamente en cuenta el fondo, este puede causar una mayor contaminacion aparente de armonicos, la cual, a su vez, puede interpretarse como un fondo aparente. Por ello es

  2. Application of radioisotopes to the investigation of the kinetics and mechanism of reactions of some inorganic complex compounds; Application des radioisotopes a l'etude de la cinetique et du mecanisme des reactions de certains complexes inorganiques; Primenenie radioizotopov k issledovaniyam kinetiki i mekhanizma reaktsij nekotorykh neorganicheskikh slozhnykh soedinenij; Aplicacion de los radioisotopos al estudio de la cinetica y del mecanismo de las reacciones de algunos complejos inorganicos

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Gordon M [Department of Chemistry, University of Buffalo, Buffalo 14, NY (United States)

    1962-03-15

    certains atomes ou radicaux, dans des reactions inorganiques pour lesquelles il faut choisir entre differentes explications, est souvent facilitee par l'emploi d'indicateurs radioactifs. C'est ainsi qu'on a pu prouver que le cyanure n'est pas un produit intermediaire qui subit un echange rapide dans l'oxydation de l'ion thiocyanate par le peroxyde d'hydrogene, quoique le cyanure soit un produit final important de la reaction. (author) [Spanish] Los radioisotopos constituyen medios auxiliares de incalculable valor para el estudio de muchos tipos de reacciones de la quimica inorganica, especialmente de aquellas en que intervienen iones complejos en solucion acuosa. Uno de sus aspectos mas importantes es la determinacion de las velocidades de reaccion y del mecanismo de los intercambios isotopicos. Por ejemplo, el autor ha realizado una serie de estudios sobre el intercambio entre carbonato ''libre'' marcado con carbono-14 y carbonato ligante en iones complejos octaedricos del tipo CoA{sub 2}CO{sub 3}{sup +}, donde A = 2NH{sub 3}, etilendiamina (en), propilendiamina (pn) o trimetilendiamina (tn). Estos estudios han permitido comprender a fondo la naturaleza de las reacciones de sustitucion de ligantes de este tipo y del papel que desempenan en el proceso los ligantes amino que no experimentan intercambio. Igualmente fructiferos han sido unos estudios analogos del intercambio de restos oxalato en complejos trioxalicos de formula M (C{sub 2}O{sub 4}){sub 3}{sup 3-}, en la que M = Co (III), Cr (III) o Rh (III). Otra tecnica, que puede aplicarse solamente cuando se emplean radioisotopos de bajo peso atomico, tales como el carbono-14, consiste en observar los efectos de equilibrio o los efectos cineticos que los isotopos ejercen sobre la reaccion. Como ejemplo, el autor ha logrado interpretar diferencias entre los mecanismos de intercambio de los restos carbonato ligantes entre el Coen{sub 2}CO{sub 3}{sup +} y el Cotn{sub 2}CO{sub 3}{sup +} por medicion del efecto isotopico, en

  3. Isotope age of the rare metal pegmatite formation in the Kolmozero-Voron'ya greenstone belt (Kola region of the Fennoscandian shield): U-Pb (TIMS) microlite and tourmaline dating

    Science.gov (United States)

    Kudryashov, Nikolay; Lyalina, Ludmila; Mokrushin, Artem; Zozulya, Dmitry; Groshev, Nikolay; Steshenko, Ekaterina; Kunakkuzin, Evgeniy

    2016-04-01

    The Kolmozero-Voron'ya greenstone belt is located in the central suture zone, which separates the Murmansk block from the Central-Kola and the Keivy blocks. The belt is represented by volcano-sedimentary rocks of Archaean age of 2.9-2.5 Ga. Rare metal pegmatites (Li, Cs with accessory Nb, Ta, and Be) occur among amphibolite and gabbroid intrusions in the northwestern and southeastern parts of the belt. According to the Rb-Sr data, the age of pegmatites was considered to be 2.7 Ga. Until recently there was no generally accepted point of view on the origin of pegmatites. Now we have isotopic data for a range of rock complexes that could pretend to be parental granites for the rare metal pegmatites. These are granodiorites with the zircon age of 2733±Ma, and microcline and tourmaline granites, which Pb-Pb isochronal age on tourmaline from the tourmaline granite located near the deposit is estimated to be 2520±70 Ma. The pegmatite field of the Vasin Myl'k deposit with the lepidolite--albite--microcline--spodumene--pollucite association is located among amphibolites in the northwestern part of the belt. The deposit is represented by subparallel low-angle zoned veins up to 220 m long and 5 m thick dipping in the southeastern direction at an angle of 10° too 30°. The minerals of the columbite--tonalite group from Vasin Myl'k deposit include microlite, simpsonite, and torolite, and are the oldest among different minerals represented by several generations in pegmatites under consideration. Zircons from the pegmatites are mostly represented by crystals with the structure affected by the action of fluids that put certain restrictions on its use as a geochronometer of the crystallization process. Microlite from the pegmatite taken from the dump of a prospecting drill hole was used for U--Pb (TIMS). The mineral is represented by 0.5--1.0 mm long euhedral octahedral crystals. It is brown in color, and transparent. The microlite crystals were preliminarily cleaned from

  4. Perspectives for Li- and Ta-Mineralization in the Borborema Pegmatite Province, NE-Brazil: A review

    Science.gov (United States)

    Beurlen, Hartmut; Thomas, Rainer; da Silva, Marcelo R. Rodrigues; Müller, Axel; Rhede, Dieter; Soares, Dwight Rodrigues

    2014-12-01

    The increasing strategic importance of Li- and Ta-ores during the last decades due to the strong consumption growth for rechargeable batteries and high temperature and corrosion resistant capacitors reactivated the interest of studies in pegmatite fields around the world, because these rocks supply respectively 25% and 100% of the world consumption in these elements. Research on petrogenetic issues and major and accessory mineral chemistry variations in rare element (REL)-pegmatites of the Borborema Pegmatite Province in Northeast Brazil were tested as tools for the diagnosis of the metallogenetic potential of rare metals in individual pegmatites and in the province as a whole along the last dozen of years. The results allowed to establish the nearly isobaric (3.8 kbar) crystallization conditions of the REL-pegmatites between approximately 580 °C (liquidus) and 400 °C (solidus) from a peraluminous melt saturated in an aquo-carbonic medium to low salinity volatile phase and an immiscible peralkaline flux-enriched (H2O, CO2, F, B, Li etc.) melt fraction, based on melt and fluid inclusion studies. Mineral-chemistry data from 30 selected REL-pegmatites in the province allowed to classify three of them as being of the complex-spodumene or -lepidolite subtype in Černý's classification. Both subtypes are supposed to be potentially fertile, (highly fractionated, and with good chances to bear Li- and Ta-ore concentrations). It was also possible to identify several pegmatitic granite intrusions with textural and lithogeochemical characteristics also found in source granites of REL-pegmatite provinces elsewhere. Preliminary chemical Pb/U/Th geochronological determinations in uraninite and xenotyme crystals of these granites indicate an age of 520 ± 10 Ma and match recently published Ar/Ar in mica and U/Pb ages in columbite-group minerals (CGM) of the REL-pegmatites between 509 and 525 Ma. Mineral-chemistry data from grains of the outer zones of the pegmatites do not

  5. The Use of Tribocharging in the Electrostatic Beneficiation of Lunar Simulant

    Science.gov (United States)

    Trigwell, S.; Captain, J. G.; Arens, E. E.; Captain, J. E.; Quinn, J. W.; Calle, C. I.

    2007-01-01

    Any future lunar base and habitat must be constructed from strong dense materials in order to provide for thermal and radiation protection. Lunar soil may meet this need. Lunar regolith has high concentrations of aluminum, silicon, calcium, iron, sodium, and titanium oxides. Refinement or enrichment of specific minerals in the soil before it is chemically processed may be more desirable as it would reduce the size and energy requirements required to produce the virgin material and it may significantly reduce the process' complexity. Also, investigations into the potential production of breathable oxygen from oxidized mineral components are a major research initiative by NASA. In this study. the objective was to investigate the use of tribocharging to charge lunar simulants and pass them through a parallel plate separator to enrich different mineral fractions. This technique takes advantage of the high Lunar vacuum in which much higher voltages can be used on the separation plates than in air. Additionally, the Lunar g1avity, only being 1/6 that of Earth, allows the particles more separation time between the plates and therefore enhances separation. For the separation studies, two lunar stimulants were used. The first simulant was created in-house, labeled KSC-1. using commercially supplied (sieved to 325 mesh) materials, and was composed of 40 wt. % feldspar ((Na,K,Ca)AlSi3O8;SiO2), 40 wt. % olivine ((Mg,Fe)2SiO4), 10 wt. % ilmenite (FeTiO3). and 10 wt. % spodumene (LiAlSi2O6) (pyroxene). The advantage of the in-house mixture is that the composition can he varied to simulate different soil compositions from different areas on the moon. This simulant was used to show proof-of-concept using the designed separator in air. The second stimulant was JSC-1. used for the vacuum experiments. JSC-1 is principally basalts, containing phases of plagioclase. pyroxene. olivine, and ilmenite. The JSC-1 was sieved to provide a 50-75 micron size range to correlate with the mean

  6. Using a robotics competition to teach about and stimulate enthusiasm for Earth science and other STEM topics

    Science.gov (United States)

    Fike, Hildee; Barnhart, Paul; Brevik, Corinne E.; Brevik, Eric C.; Burgess, Cynthia; Chen, Jundong; Egli, Shawna; Harris, Billy; Johanson, Paul J.; Johnson, Naomi; Moe, Marie; Olsen, Reba

    2016-04-01

    One of the major challenges in recruiting students to careers in STEM (science, technology, engineering, and mathematics) fields is to stimulate enthusiasm about these fields in our youth. BEST (Boosting Engineering Science and Technology) Robotics is a national program in the USA that attempts to recruit junior and senior high school students (ages 13-18) into STEM careers by showing youth how exciting these careers can be by using robotics competitions. The competitions have several aspects, including robot design, software engineering, marketing, public outreach, research into the subject area of the year's tasks, and a set of tasks to be physically performed by the robots that each team builds. The tasks to be performed change every year; therefore, even teams that compete over multiple years must build a new robot each year designed to perform the particular tasks charged to them. Dickinson State University is the home to Blue Hawk BEST, one of the hubs that host the first round of competition for teams hoping to move on to regional, and potentially, national level competition. The tasks for 2015 revolved around a mining theme. The robots needed to be able to replace the filter in an air filtration system, fix broken pipes, mine simulated aggregate, coal, magnetite, bauxite, chalcopyrite, and spodumene, and move core samples. Points were awarded for successful progress toward each task based on the difficulty of the task and the market value of the commodities. While several STEM fields are covered in various aspects of the competition, the 2015 competition includes Earth science in that the students are required to research the history and science of the commodities being mined and learn about ways the commodities are important to their lives and the economy of their particular region. Several awards are handed out to the top performing teams in various categories, including spirit and sportsmanship awards. As teams compete for these awards a raucous

  7. Crystallization characteristics and physico-chemical properties of glass–ceramics based on Li2O–ZnO–SiO2 system; Características de cristalización y propiedades físico-químicas de los materiales vitrocerámicos compuestos a base del sistema Li2O-ZnO-SiO2

    Energy Technology Data Exchange (ETDEWEB)

    Salman, Saad M.; Salama, Samia N.; Abo-Mosallam, Hany A.

    2017-11-01

    Glass materials based on lithium zinc silicate system of the composition 24Li2O–20ZnO–56SiO2 LZS (mol%) were prepared and converted to glass–ceramics using controlled heat-treatment schedules. The LZS base glass system was modified by addition of Al2O3 and MO/ZnO replacements where MO=CaO, CdO and SrO oxides. Several crystalline phases were developed, including lithium zinc orthosilicate, α-quartz, β-spodumene solid solution, lithium meta and disilicate, Ca-wollastonite, Cd or Sr metasilicate, and Sr-zinc silicate of hardystonite type. The effects of crystallization process on some properties, like thermal expansion coefficient (TEC), chemical stability, and density of glass–ceramics were evaluated. The TEC of crystalline samples varied from 72×10−7 to 149×10−7K−1, 25–600 and density values in the range, 2.67–3.29g/cm3. The addition of Al2O3 and MO/ZnO replacements in the base glass led to improve the chemical durability of the glass–ceramics samples. As a result of the thermal and physico-chemical properties of the studied glass–ceramic, the materials acquire excellent properties and can be used to seal a variety of different metals and alloys. [Spanish] Los materiales de vidrio compuestos a base del sistema de silicato de cinc y de litio, de la composición 24Li2O–20ZnO-56SiO2 LZS (mol %), se prepararon y se convirtieron en vitrocerámica con regímenes de tratamiento térmico controlado. El sistema de vidrio de base LZS se modificó mediante la adición de reemplazos de Al2O3 y MO/ZnO, donde MO=óxidos de CaO, CdO y SrO. Se desarrollaron varias fases cristalinas, incluyendo ortosilicato de cinc y de litio, de cuarzo α, solución sólida de espomudeno, metal litio y disilicato, Ca-wollastonita, metasilicato Cd o Sr, y silicato de cinc Sr de tipo hardistonita. Se evaluaron los efectos del proceso de cristalización en algunas propiedades, como el coeficiente de expansión térmica, la estabilidad química y la densidad de las vitrocer

  8. Diffusive Fractionation of Lithium Isotopes in Olivine Grain Boundaries

    Science.gov (United States)

    Homolova, V.; Watson, E. B.

    2012-12-01

    Diffusive fractionation of isotopes has been documented in silicate melts, aqueous fluids, and single crystals. In polycrystalline rocks, the meeting place of two grains, or grain boundaries, may also be a site of diffusive fractionation of isotopes. We have undertaken an experimental and modeling approach to investigate diffusive fractionation of lithium (Li) isotopes by grain boundary diffusion. The experimental procedure consists of packing a Ni metal capsule with predominantly ground San Carlos olivine and subjecting the capsule to 1100C and 1GPa for two days in a piston cylinder apparatus to create a nominally dry, 'dunite rock'. After this synthesis step, the capsule is sectioned and polished. One of the polished faces of the 'dunite rock' is then juxtaposed to a source material of spodumene and this diffusion couple is subject to the same experimental conditions as the synthesis step. Li abundances and isotopic profiles (ratios of count rates) were analyzed using LA-ICP-MS. Li concentrations linearly decrease away from the source from 550ppm to the average concentration of the starting olivine (2.5ppm). As a function of distance from the source, the 7Li/6Li ratio decreases to a minimum before increasing to the background ratio of the 'dunite rock'. The 7Li/6Li ratio minimum coincides with the lowest Li concentrations above average 'dunite rock' abundances. The initial decrease in the 7Li/6Li ratio is similar to that seen in other studies of diffusive fractionation of isotopes and is thought to be caused by the higher diffusivity (D) of the lighter isotope relative to the heavier isotope. The relationship between D and mass (m) is given by (D1/D2) =(m2/m1)^β, where β is an empirical fractionation factor; 1 and 2 denote the lighter and heavier isotope, respectively. A fit to the Li isotopic data reveals an effective DLi of ~1.2x10^-12 m/s^2 and a β of 0.1. Numerical modelling was utilized to elucidate the relationship between diffusive fractionation

  9. Production of hydrogen using the combination of water-gas shift and carbonatation reaction of a CO{sub 2} absorbent; Produccion de hidrogeno mediante la combinacion de las reacciones de desplazamiento de agua y carbonatacion de un absorbente de CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Escobedo-Bretado, M. A.; Ponce-Pena, P. [Facultad de Ciencias Quimicas, UJED, Durango, Durango (Mexico)]. E-mail: miguel.escobedo@ujed.mx; Delgado-Vigil, M. D.; Salinas-Gutierrez, J. M.; Lopez Ortiz, A.; Collins-Martinez, V.H. [Centro de Investigacion en Materiales Avanzados, S.C., Chihuahua, Chihuahua (Mexico)

    2009-09-15

    separacion de CO{sub 2} en un solo paso AEWGS (Absorption Enhanced Water Gas Shift). Esta combinacion de reacciones fue estudiada a escala laboratorio utilizando un reactor de cama fija fabricado en cuarzo. Los absorbentes probados fueron Dolomita Calcinada (CaO*MgO) y Zirconato de Sodio (Na{sub 2}ZrO{sub 3}), en mezclas de catalizador/absorbente (cat/abs) con relaciones en peso de 1/1, 1/2 y 2/1, utilizando un catalizador de alta temperatura de la reaccion WGS sintetizado en laboratorio (Fe-Cr). En todas las pruebas se utilizaron 3cm{sup 3} de cat/abs, una alimentacion compuesta de 5% CO, 15% H{sub 2}O, 10.5% He y 69.5% N{sub 2}, una velocidad espacial (SV) de 1500h-1, 600 grados centigrados y presion atmosferica. El catalizador presento conversion de CO a CO{sub 2} del 100% manteniendo su area superficial despues de reaccion (12 m2/g). Los resultados en base seca utilizando la mezcla cat/abs de 1/2 y utilizando CaO*MgO genero un 95% de H2 acompanado de un 5% de CO{sub 2} libre de CO, mientras que con Na2ZrO{sub 3}, la maxima concentracion de H{sub 2} fue 70%, 29% CO{sub 2} y 1% de CO sin reaccionar. Los resultados empleando unicamente CaO*MgO (como material bifuncional) presentaron una concentracion de H{sub 2} maxima de 96% y una minima de 4% CO{sub 2}, sin embargo, hacia el final de la reaccion aparece CO sin reaccionar presumiblemente al formarse el CaCO{sub 3}; mientras que con Na{sub 2}ZrO{sub 3} se obtuvo un 63% de H{sub 2}, 30% de CO{sub 2}, asi como un 7% de CO sin reaccionar, el cual fue atribuido a efectos cineticos.

  10. Determination of selenium and zinc in rat plasma by instrumental neutron activation analysis; Determinacion de selenio y zinc en plasma mediante analisis por activacion neutronica instrumental

    Energy Technology Data Exchange (ETDEWEB)

    Munoz A, Luis

    1998-12-31

    To evaluate the effects on the thyroid function when simple or multiple zinc, selenium and iodine deficiency are induced, research was carried out in laboratory animals. For simultaneously determining the Zn and Se concentration in rat plasma, an instrumental neutron activation analysis technique was applied. A clean laboratory, was used for the preparation of samples. High purity materials were used for sample collection and storage. Irradiation, decay and counting parameters were optimized to obtain the best sensitivity, accuracy and precision analysis. The Zn and Se concentrations were determined from the peak area of gamma-rays of 1115 and 265 KeV respectively. The analytical methodology used was validated with standard reference materials. The procedure used for the analysis, including the phases of collection, treatment of the samples and analytical determination was considered suitable for the study of trace elements in biological samples, especially plasma. (author). Dissertation to obtain the title of Bachelor in Chemistry; 46 refs., 12 figs., 17 tabs. [Espanol] Con el proposito de evaluar los efectos que se producen sobre la funcion tiroidea cuando se induce un deficiencia simple o multiple de zinc, selenio y yodo, se llevo a cabo una investigacion en animales de experimentacion. Se aplico la tecnica de analises por activacion neutronica instrumental para la determinacion de Se y Zn en plasma de ratas. Se utilizo un laboratorio limpio clase 100 para la preparacion de las muestras y se emplearon materiales de alta pureza para su recoleccion y almacenamiento. Se optimizaron los parametros de irradiacion, decaimiento y conteo de las muestras con el proposito de alcanzar la mejor sensibilidad, exactitud y precision analitica. Las concentracion de Se y Zn fueron determinadas evaluando las areas de los fotopicos de 265 y 1115 KeV respectivamente. El metodo analitico fue validado utilizando materiales de referencia. El procedimiento utilizado para el analisis

  11. Seismic pressure effect on retaining walls; Presiones generadas por sismo en muros de retencion

    Energy Technology Data Exchange (ETDEWEB)

    Bonola, Isaac; Aviles, Javier [Instituto Mexicano de Tecnologia del Agua, Jiutepec, Morelos (Mexico)

    2006-04-15

    Retaining walls are auxiliary works used in different hydraulic structures. In seismically active areas, the dynamic pressures generated by the backfill must be appropriately evaluated at the design stage. Currently, a number of methods for estimating the seismic response of this type of works are available; however, most of them are simplified and not all the parameters involved have been examined. In this paper, a hybrid boundary and finite element method is presented for gravity walls in which the backfill can be represented by a horizontally layered medium. The effect of lateral extension of the backfill can be included in the model by introducing a vertical boundary coupling the movement of the backfill with that of the surrounding soil. The wave propagation analysis in the layered medium is carried out for both horizontal and vertical harmonic excitation; the latter excitation may cause important responses under certain situations. To illustrate the applicability of the proposed method, results for two numerical examples are presented: one for dry backfill and other for saturated backfill, considering in both cases the variations of dynamic properties of the soil with the depth. [Spanish] Los muros de retencion son estructuras auxiliares utilizadas en distintas obras hidraulicas. En zonas sismicas, las presiones dinamicas generadas por el relleno deben evaluarse adecuadamente en la etapa de diseno. Actualmente existen numerosos metodos para estimar la respuesta sismica de este tipo de estructuras; sin embargo, la mayoria de ellos son simplificados y no todos los parametros involucrados han sido examinados. En este trabajo se presenta un metodo hibrido de frontera y elemento finito para muros de gravedad en el que el relleno puede representarse por un medio estratificado horizontalmente. En el modelo puede incluirse el efecto de la extension lateral del relleno, introduciendo una frontera vertical que acopla el movimiento del relleno con el del suelo

  12. Darbo metu susenėjusių ir po suvirinimo termiškai apdorotų plieno 5 % Cr-0,5 % Mo virintinių jungčių struktūra ir savybės

    Directory of Open Access Journals (Sweden)

    Vigantas KUMŠLYTIS

    2012-06-01

    Full Text Available Straipsnyje nagrinėjamos suvirintos ir termiškai apdorotos chromo ir molibdeno (5 % Cr – 0,5 % Mo grupės plieno vamzdžių jungtys. Taip pat pateikiami ir palyginami ilgą laiką aukštoje temperatūroje eksploatuoto ir naujo chromo ir molibdeno plieno vamzdžio struktūra ir mechaninių savybių tyrimai. Eksploatuoto metalo tyrimams buvo panaudotas 530 °C temperatūroje 100 000 valandų dirbęs plieninis vamzdis. Tyrimais siekiama nustatyti 5 % Cr – 0,5% Mo grupės plienų suvirintųjų jungčių mechaninių savybių ir terminio apdorojimo parametrų tarpusavio priklausomybes. Atlikti suvirintų bandinių struktūros radiografiniai, mechaninių savybių, lūžių analizės ir mikrostruktūrų tyrimai. Nustatyta, kad chromo ir molibdeno plienų virintinių jungčių vidiniams įtempiams mažinti turi būti taikomas tik terminis apdorojimas. Kiti įtempių mažinimo metodai šiems plienams yra nepriimtini. Nustatyta, kad 5 % Cr – 0,5 % Mo plienų virintinių jungčių terminio apdorojimo temperatūros ir laiko parametro P reikšmė neturi viršyti 20,5. Viršijus šią reikšmę vyksta struktūros degradacijos procesas, karbidai pamažu transformuojasi į M23C6 karbidus, koaguliuoja ferito grūdelių ribose, sudaro karbidų kolonijas ar jungiasi į ilgus vientisus junginius. Smulkių, dispersiškų karbidų struktūroje nelieka. Taip pat mažėja jungties metalo takumo stipris ir smūginis tąsumas.DOI: http://dx.doi.org/10.5755/j01.ms.18.2.1911

  13. Determination of lead in papers and cardboards for food packaging; La determinazione del piombo in carte e cartoni per alimenti. Giornata di studio

    Energy Technology Data Exchange (ETDEWEB)

    Costantini, S.; Giordano, R. [eds.] [Istituto Superiore di Sanita`, Rome (Italy). Lab. di Tossicologia Applicata

    1998-06-01

    The meaning of a legal limit of lead in papers for food packaging is based on the fact that a material having high amount of lead could potentially contain other contaminants. The sample preparation represents a very important step that must be carefully considered in order to have a correct final result. The atomic absorption graphite furnace resulted the most utilized technique, since it offers both good accuracy and sensitivity; nevertheless, numerous factors influencing the determination must be considered. Besides obtaining accurate values, the problem is to take correct decision in presence of a variability not eliminable; in this case, the statistics can give a valid help by means of a mathematical model. The suitability of the materials used in a Quality control programme must be considered a parameter of capital importance, since the performance of the laboratories could be heavily influenced by the quality of samples. During 1997, a collaborative trial has been carried out with the participation of 70 laboratories of the national service. [Italiano] Il significato della presenza di un limite di piombo nelle carte destinate al contatto con alimenti risiede nel fatto che un materiale che non rispetta tale parametro puo` contenere altri contaminanti non prevedibili. La preparazione del campione da sottoporre alla determinazione e` una fase molto delicata da non sottovalutare ai fini della correttezza del risultato analitico finale. La tecnica dell`assorbimento atomico a fornace di grafite e` risultata la piu` utlizzata, in funzione delle buone accuratezza e sensibilita` del metodo; tuttavia, numerosi fattori che possono influenzare negativamente questo tipo di analisi devono essere tenuti in considerazione. Datala presenza di un limite di legge, il problema non e` solo quello di ottenere valori precisi ed accurati, ma di prendere decisioni corrette in presenza di una variabilita` di fondo non eliminabile. La statistica decisionale, attraverso un modello

  14. Flashback analysis in tangential swirl burners; Analisis de reflujo de flama en combustores tangenciales de flujo giratorio

    Energy Technology Data Exchange (ETDEWEB)

    Valera-Medina, A. [CIATEQ A.C., Centro de Tecnologia Avanzada, Queretaro (Mexico)]. E-mail: agustin.valera@ciateq.mx; Syred, N. Abdulsada, M. [United Kingdom Cardiff University (United Kingdom)]. E-mails: syredn@cf.ac.uk; abdulsadam@cf.ac.uk

    2011-10-15

    Premixed lean combustion is widely used in Combustion Processes due to the benefits of good flame stability and blow off limits coupled with low NO{sub x} emissions. However, the use of novel fuels and complex flows have increased the concern about flashback, especially for the use of syngas and highly hydrogen enriched blends. Thus, this paper describes a combined practical and numerical approach to study the phenomenon in order to reduce the effect of flashback in a pilot scale 100 kW tangential swirl burner. Natural gas is used to establish the baseline results and effects of different parameters changes. The flashback phenomenon is studied with the use of high speed photography. The use of a central fuel injector demonstrates substantial benefits in terms of flashback resistance, eliminating coherent structures that may appear in the flow channels. The critical boundary velocity gradient is used for characterization, both via the original Lewis and von Elbe formula and via analysis using CFD and investigation of boundary layer conditions in the flame front. [Spanish] La combustion ligera premezclada se utiliza ampliamente en los procesos de combustion debido a los beneficios que brinda en terminos de buena estabilidad de flama y limites de extincion, aunado a la baja emision de NO{sub x}. Sin embargo, el uso de nuevos combustibles y de flujos complejos han incrementado la preocupacion por el reflujo de flama, especialmente para el uso de gas sintetico (syngas) y mezclas altamente hidrogenadas. Por ello, en este articulo se describe un metodo practico y numerico para el estudio del fenomeno a modo de reducir los efectos del reflujo de flama en un combustor piloto de tipo tangencial de flujo giratorio de 100 kW. Se usa gas natural para establecer la linea base de resultados y los efectos del cambio de diferentes parametros. El fenomeno de reflujo de flama se estudia por medio de fotografia de rapida adquisicion. El uso de un inyector central de combustible

  15. Quantitative physic behavior of fine soils: collapsible aeolian and expansive residual; Comportamiento fisico cuantitativo de los suelos finos: eolicos colapsibles y residuales expansivos

    Energy Technology Data Exchange (ETDEWEB)

    Zeevaert-Wiechers, L. [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    2000-06-01

    apoyan sobre ellos. De ahi la necesidad de conocer los parametros cuantitativos que rigen el comportamiento estatico y dinamico de este tipo de suelos en relacion con los cambios ambientales de humedad. La investigacion basica es importante y necesaria en mecanica de suelos e ingenieria de cimentaciones, y debera efectuarse en los diferentes tipos de suelos que se encuentran en la naturaleza. Se muestran las curvas de compresibilidad de sedimentos eolicos finos, asi como curva de colapsos por hidratacion de suelo tipo loessial. Se presenta una figura de la relacion de colapsos, de esfuerzos y finalmente se da una tabla de los elementos.

  16. La función característica de punto de Hamilton y la función de tiempos de difracción de la sísmica geométrica en la migración con amplitudes verdaderas

    Directory of Open Access Journals (Sweden)

    Montes Vides Luis Alfredo

    2000-08-01

    Full Text Available

    Using the paraxial ray theory in the second order approximation of the traveltimes, we can estimate the traveltime function of a wavefront coming from a reflector, and in consequence calculate the diffraction traveltime function associated with a diffractor point located on the reflector. The numerical knowledge of those two functions makes possible a process to migrate stacked sections in time, process which generate images of seismic sections with true amplitudes. The restitution of the wave amplitude is made using an operator which depends of the parameters of the traveltime function A differentiation filter is applied to the migrated sections in order to obtain the original wave phase. Layered models with smooth interfaces are used.

    Usando la teoría del rayo paraxial en la aproximación de segundo de los tiempos de tránsito, podemos estimar la función de tiempos de tránsito asociada a un frente de onda proveniente de un reflector, y en consecuencia calcular la función de tiempos de difracción de un frente de onda generado por un punto difractor situado en el reflector. EI conocimiento numérico de estas funciones hace posible un proceso de migración en tiempo de secciones apiladas que generan imágenes de secciones sísmicas con amplitudes verdaderas. La restitución de la amplitud de la onda se realiza mediante un operador que es función de los parametros de la función tiempo de transito. A las secciones migradas se les aplica un filtro de diferenciación para obtener las fases iniciales del campo de onda. Se usan modelos de capas separadas por interfaces suaves.

  17. Effect of the acid rain in the constituent material of the Mayan Mexican monuments; Efecto de la lluvia acida en el material constituyente de los monuments mayas mexicanos

    Energy Technology Data Exchange (ETDEWEB)

    Bravo Alvarez, H; Soto Ayala, R; Sosa Echeverria, R; Sanchez Alvarez, P [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    2003-10-15

    Actually, acid rain is considered as a potential problem that affects materials and ecosystems. The effect on monuments, made mainly from limestone, has been studied for long time. In this work, a sample of limestone from Tulum, Qintana Roo, was studied. The following parameters were measured: density, porosity and percentage of water adsorption. Also, the sample was irrigated with acid rain prepared in the laboratory (pH = 4.6), based in the chemical composition of 56 rain samples from Puerto Morelos, Quintana Roo, in 1994 and 1995. The results obtained show that acid rain is neutralized by calcium carbonate from the limestone. The high calcium concentrations in the effluent, show that limestone is dissolved by acid rain. Superficial recession was 4.4 {mu}m/year under experimental conditions used. [Spanish] Actualmente la lluvia acida se ha convertido en un problema potencial que afecta en mayor o menor grado a materiales y a los ecosistemas. El efecto que causa la lluvia acida en monumentos construidos fundamentalmente de roca caliza, ha sido objeto de muchas investigaciones realizadas, prioritariamente, por paises que poseen estructuras, cuyo material de construccion es caliza. En este trabajo de investigacion se estudio una muestra de roca caliza proveniente de los monumentos mayas de Tulum, Quintana Roo. Se determinaron los parametros de densidad, porosidad y porcentaje de adsorcion de agua. Asimismo, se efectuo la irrigacion de la muestra con lluvia acida (pH aprox.4.6), preparada en el laboratorio con base en la composicion quimica que se determino en 56 muestras de agua de lluvia provenientes de Puerto Morelos, punto cercano a los monumentos de Tulum, Quintana Roo, durante los anos 1994 y 1995. Los resultados permiten concluir que la lluvia acida sufre un proceso de naturalizacion con el carbonato de calcio de la roca caliza. Las altas concentraciones de calcio en el efluente, mostraron que la roca caliza sufrio una disolucion con la lluvia acida. La

  18. Acid rain effect in the constituent material of Mexican Mayan monuments; Efecto de la lluvia acida en el material constituyente de los monumentos Mayas mexicanos

    Energy Technology Data Exchange (ETDEWEB)

    Bravo Alvarez, H.; Soto Ayala, R.; Sosa Echeverria, R.; Sanchez Alvarez, P. [Facultad de Ingenieria, UNAM, Mexico, D.F. (Mexico)

    2003-12-01

    Actually, acid rain is considered as a potential problem that affects materials and ecosystems. The effect on monuments, made mainly from limestone, has been studied for long time. In this work, a sample of limestone from Tulum, Quintana Roo, was studied. The following parameters were measured: density, porosity and percentage of water adsorption. Also, the sample was irrigated with acid rain prepared in the laboratory (pH 4.6), based in the chemical composition of 56 rain samples from Puerto Morelos, Quintana Roo, in 1994 and 1995. The results obtained show that acid rain is neutralized by calcium carbonate from the limestone. The high calcium concentrations in the effluent show that limestone is dissolved by acid rain. Superficial recession was 4.4 {mu}m/year under experimental conditions used. [Spanish] Actualmente la lluvia acida se ha convertido en un problema potencial que afecta en mayor o menor grado a materiales y a los ecosistemas. El efecto que causa la lluvia acida en monumentos construidos fundamentalmente de roca caliza, ha sido objeto de muchas investigaciones realizadas, prioritariamente, por paises que poseen estructuras, cuyo material de construccion es caliza. En este trabajo de investigacion se estudio una muestra de roca caliza proveniente de los monumentos mayas de Tulum, Quintana Roo. Se determinaron los parametros de densidad, porosidad y porcentaje de adsorcion de agua. Asimismo, se efectuo la irrigacion de la muestra con lluvia acida (pH aprox. 4.6), preparada en el laboratorio con base en la composicion quimica que se determino en 56 muestras de agua de lluvia provenientes de Puerto Morelos, punto cercano a los monumentos de Tulum, Quintana Roo, durante los anos 1994 y 1995. Los resultados permiten concluir que la lluvia acida sufre un proceso de neutralizacion con el carbonato de calcio de la roca caliza. Las altas concentraciones de calcio en el efluente, mostraron que la roca caliza sufrio una disolucion con la lluvia acida. La

  19. Overview on the permanent magnets technology of rare earth based on Nd-Fe-B; Panorama general sobre tecnologia de imanes permanentes de tierras raras a base de Nd-Fe-B

    Energy Technology Data Exchange (ETDEWEB)

    Rosales Vazquez, Maria Ines [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1990-12-31

    In this paper the technological development in the area of permanent magnetic materials, is shown, from the 1930`s when the first aluminum-nickel-cobalt (Al-Ni-Co) magnets appeared. As a result of the continuous worldwide research in this field, it was made known, during the 1980`s decade of a new type of magnets based on Neodymium (Nd). In accordance with the outstanding magnetic properties of these magnets, at the Instituto de Investigaciones Electricas (IIE), their development was initiated, focussed on the stages and parameters definition of their manufacturing process. Up to now, the research has been oriented to the preparation of magnets of the isotropic agglutinated type and the manufacturing process encompasses the following stages: a) Alloy preparation; b) Microcrystals obtainment; c) Magnet preparation. The preliminary results that have been obtained in the magnetic characterization show that the quality of the prepared magnets is comparable to the quality of the imported magnets and/or to the ones other research groups report. [Espanol] En este trabajo se muestra el desarrollo tecnologico del area de materiales magneticos permanentes a partir de los anos treinta en que surgieron los primeros imanes de aluminio-niquel-cobalto (Al-Ni-Co). Como resultado de la constante investigacion a nivel mundial en ese campo, durante el decenio de los ochenta se informo en torno a un nuevo tipo de imanes a base de neodimio (Nd). Atendiendo a las propiedades magneticas sobresalientes de estos imanes, en el Instituto de Investigaciones Electricas (IIE), se inicio el desarrollo de los mismos, enfocandolo a la definicion de las etapas y parametros del proceso de fabricacion. Hasta ahora, la investigacion se ha orientado a la preparacion de imanes de tipo isotropico aglutinado y el proceso de fabricacion comprende las etapas: a) preparacion de la aleacion; b) obtencion de microcristales, y c) preparacion de los imanes. Los resultados preliminares que se han obtenido en la

  20. Heat transfer equipment performance diagnosis of auxiliary systems in electric power stations; Diagnostico de comportamiento de equipo de transferencia de calor de sistemas auxiliares de centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Esparza Gutierrez, Rogelio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1990-12-31

    In this article the methodology followed to diagnose the performance of the equipment where heat is transferred from the feed water, condensate and circulation water systems in fossil power plants (FPP). The data collection is made with the unit in normal operation, using local instrumentation without taking the equipment out of service for its installation. The equipment diagnosis is made through the analysis of the collected data in actual operation and the design data; for this purpose a thermal balance of the interested systems is performed to obtain all the conditions an operation data. Later on the performance indicative parameters (PIP) of actual operation and design are calculated and compared one against the other. Such a comparison reveals the performance deterioration and the possible equipment faults. The data obtained and the supplementary information are stored in a data base whose objective is that Comision Federal de Electricidad has on hand a prompt access to them in order to control the performance, compare them among similar units and power stations, and inclusively verify possible recurrent causes of low availability in the referred systems. [Espanol] En este articulo se presenta la metodologia seguida para diagnosticar el comportamiento de equipos en los que se transfiere calor de los sistemas de agua de alimentacion, condensado y circulacion de las centrales termoelectricas (CTE). La toma de datos se realiza con la unidad en operacion normal, utilizando instrumentacion local sin necesidad de sacar de servicio a los equipos para su instalacion, ya que se ocupan los mismos puntos para instrumentos con que cuentan por diseno. El diagnostico de los equipos se realiza mediante el analisis de los datos recopilados, tanto de operacion real como de diseno; para ello, se efectua un balance termico de los sistemas de interes para obtener todas las condiciones y los datos de operacion. Posteriormente, se calculan los parametros indicativos de

  1. Heat transfer equipment performance diagnosis of auxiliary systems in electric power stations; Diagnostico de comportamiento de equipo de transferencia de calor de sistemas auxiliares de centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Esparza Gutierrez, Rogelio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1991-12-31

    In this article the methodology followed to diagnose the performance of the equipment where heat is transferred from the feed water, condensate and circulation water systems in fossil power plants (FPP). The data collection is made with the unit in normal operation, using local instrumentation without taking the equipment out of service for its installation. The equipment diagnosis is made through the analysis of the collected data in actual operation and the design data; for this purpose a thermal balance of the interested systems is performed to obtain all the conditions an operation data. Later on the performance indicative parameters (PIP) of actual operation and design are calculated and compared one against the other. Such a comparison reveals the performance deterioration and the possible equipment faults. The data obtained and the supplementary information are stored in a data base whose objective is that Comision Federal de Electricidad has on hand a prompt access to them in order to control the performance, compare them among similar units and power stations, and inclusively verify possible recurrent causes of low availability in the referred systems. [Espanol] En este articulo se presenta la metodologia seguida para diagnosticar el comportamiento de equipos en los que se transfiere calor de los sistemas de agua de alimentacion, condensado y circulacion de las centrales termoelectricas (CTE). La toma de datos se realiza con la unidad en operacion normal, utilizando instrumentacion local sin necesidad de sacar de servicio a los equipos para su instalacion, ya que se ocupan los mismos puntos para instrumentos con que cuentan por diseno. El diagnostico de los equipos se realiza mediante el analisis de los datos recopilados, tanto de operacion real como de diseno; para ello, se efectua un balance termico de los sistemas de interes para obtener todas las condiciones y los datos de operacion. Posteriormente, se calculan los parametros indicativos de

  2. Overview on the permanent magnets technology of rare earth based on Nd-Fe-B; Panorama general sobre tecnologia de imanes permanentes de tierras raras a base de Nd-Fe-B

    Energy Technology Data Exchange (ETDEWEB)

    Rosales Vazquez, Maria Ines [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1991-12-31

    In this paper the technological development in the area of permanent magnetic materials, is shown, from the 1930`s when the first aluminum-nickel-cobalt (Al-Ni-Co) magnets appeared. As a result of the continuous worldwide research in this field, it was made known, during the 1980`s decade of a new type of magnets based on Neodymium (Nd). In accordance with the outstanding magnetic properties of these magnets, at the Instituto de Investigaciones Electricas (IIE), their development was initiated, focussed on the stages and parameters definition of their manufacturing process. Up to now, the research has been oriented to the preparation of magnets of the isotropic agglutinated type and the manufacturing process encompasses the following stages: a) Alloy preparation; b) Microcrystals obtainment; c) Magnet preparation. The preliminary results that have been obtained in the magnetic characterization show that the quality of the prepared magnets is comparable to the quality of the imported magnets and/or to the ones other research groups report. [Espanol] En este trabajo se muestra el desarrollo tecnologico del area de materiales magneticos permanentes a partir de los anos treinta en que surgieron los primeros imanes de aluminio-niquel-cobalto (Al-Ni-Co). Como resultado de la constante investigacion a nivel mundial en ese campo, durante el decenio de los ochenta se informo en torno a un nuevo tipo de imanes a base de neodimio (Nd). Atendiendo a las propiedades magneticas sobresalientes de estos imanes, en el Instituto de Investigaciones Electricas (IIE), se inicio el desarrollo de los mismos, enfocandolo a la definicion de las etapas y parametros del proceso de fabricacion. Hasta ahora, la investigacion se ha orientado a la preparacion de imanes de tipo isotropico aglutinado y el proceso de fabricacion comprende las etapas: a) preparacion de la aleacion; b) obtencion de microcristales, y c) preparacion de los imanes. Los resultados preliminares que se han obtenido en la

  3. Historical-statistical analysis of energy consumption in energy management; Analisis historico-estadistico del consumo energetico en la administracion de energia

    Energy Technology Data Exchange (ETDEWEB)

    Guizar Bejarano, Ruben [IMENOR (Mexico); Oven, Mark [RCG/Hagler, Bailly, Inc., Washington (United States)

    1993-12-31

    Traditionally the specific consumption of energy has been considered as the most adequate index to evaluate the efficiencies in the productive processes. Nevertheless, this index, in some instances is highly susceptible to suffer significant variations, due to factors such as equipment condition, raw materials quality, operational parameters, climate and production level. This last one definitely is the most important and requires a deeper analysis. In this presentation a methodology is developed to analyze the energy consumption as well as their specific energy consumption with respect to production. Enough historical data are utilized to allow for a statistical analysis. This study is of equal usefulness in an energy diagnosis, as in a management program of energy saving. In presenting the possibility of identifying potential energy saving, stands out the advantages of the analysis and the conclusions that can be derived from it. Through the actual data collected in several industries during the energy diagnosis, various possible results of the analysis are presented. Finally, how this type of analysis can be adapted to a more precise control of the energy consumption is described and be used as a base for establishing goals in energy efficiency in the long term. [Espanol] Tradicionalmente se ha considerado al consumo especifico de energia como el indice energetico mas adecuado para evaluar las eficiencias de los procesos productivos. Sin embargo, este indice es en ocasiones altamente susceptible a sufrir variaciones importantes, debido a factores como el estado de los equipos, la calidad de la materia prima, los parametros operativos, el clima, y el nivel de produccion. Este ultimo es decididamente el mas importante, y requiere un analisis mas profundo. En esta presentacion se desarrolla una metodologia para analizar tanto consumos de energia como consumos especificos de energia con respecto a la produccion. Se utilizan suficientes datos historicos para permitir

  4. Nissan Mexicana. First place in national prize of electrical energy saving 1998; Nissan Mexicana. Primer lugar en premio nacional de ahorro de energia electrica 1998

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez S, Enrique [Nissan Mexicana, S.A. de C.V., Planta Civac, Cuernavaca, Mor. (Mexico)

    1999-07-01

    For Plant CIVAC of Nissan Mexicana, the energy saving began in the year of 1990. From then, different programs have been developed using different strategies for energy saving until arriving at the Benchmarking with other Plants of Japan, which represents a new challenge, since it opened up an area of opportunity of saving in processes that generally were known in detail as far as to its main function (to make vehicles with quality, cost and opportunity of delivery), but the parameter of energy consumption of by unit and its benefits in relation to the cost was unknown. This was endorsed by the high Direction and began with the optimization of training for the operation of each equipment with the involvement of the user (Production), the engineering area (that establishes the process) and the maintenance area. We designed a general program where the basic activities were included, such as the general and special activities. Each one of them fulfilled its objective, but the special activities took us to the optimization of the processes, finding excess of energy in the design conditions. [Spanish] Para Planta CIVAC de Nissan Mexicana, el ahorro de energia se inicio en el ano de 1990. A partir de entonces se han desarrollado programas de ahorro de energia usando estrategias diferentes hasta llegar al Benchmarking con otras Plantas de Japon, el cual representa un reto nuevo, ya que puso al descubierto una area de oportunidad de ahorro en los procesos que por lo general se conocian a detalle en cuanto a la funcion principal (hacer vehiculos con calidad, costo y oportunidad de entrega), pero se desconocia el parametro de consumo de energia por unidad y sus beneficios en relacion con el costo. Esto fue avalado por la alta Direccion y se inicio con la capacitacion de la optimizacion de la operacion de cada equipo y se involucro al usuario (Produccion), al area de ingenieria (que establece el proceso) y al area de mantenimiento. Elaboramos un programa general donde se

  5. General and biochemical properties of forest soils on serpentinized areas of Galicia; Propiedades generales y bioquimicas de suelos forestales en areas serpentinizadas de Galicia

    Energy Technology Data Exchange (ETDEWEB)

    Pena, Wagner; Briceno, Jorge A., E-mail: wpenac@cia.ucr.ac.c [Univ. de Costa Rica, Centro de Investigaciones Agronomicas (Costa Rica); Leiros de la Pena, Maria del Carmen [Univ. de Santiago de Compostela, Dept. Edafologia y Quimica Agricola (Spain)

    2005-07-15

    The use agricultural and forest soils is normal in the territory of the Autonomous Community of Galicia for submitting the physical, chemical and agroclimatic optimum. The region has areas by the characteristics of the environment has been impossible to use agricultural and forestry. Serpentinite soils developed on frequently drew attention to the high degree of infertility, caused by nutrient deficiency and excess toxic metal content. The results of general physical and chemical properties have been analyzed of the total metal content and biochemical parameters of 28 soils on serpentinite in A Coruna Galicia, Spain. The infertility of soil organic matter, nutrients and low microbial activity and biochemistry have been caused by high level of pH and nutritional imbalance due to the high content of Mg{sup 2+}. OM (organic matter) content, total N, soluble P and exchangeable K{sup +}, were lower due to the underdevelopment of vegetation and the potential toxic effects that have metal on the biological activity in the middle. (author) [Spanish] El uso agricola y forestal de los suelos es normal en el territorio de la Comunidad Autonoma de Galicia por haber presentado las condiciones fisicas, quimicas y agroclimaticas optimas. La region tiene zonas que por las caracteristicas del medio ha sido imposible el uso agricola y forestal. Los suelos desarrollados sobre serpentinita es frecuente que hayan llamado la atencion por el elevado grado de infertilidad, provocado por la deficiencia de nutrimentos y por el exceso contenido en metales toxicos. Los resultados de las propiedades generales fisicas y quimicas han sido analizados del contenido total de metales y de parametros bioquimicos de 28 suelos sobre serpentinita en A Coruna, Galicia, Espana. La infertilidad de los suelos de materia organica, nutrimentos y baja actividad microbiana y bioquimica han sido causadas por el alto nivel de pH y el desbalance nutricional por el alto contenido de Mg{sup 2+}. El contenido de MO

  6. Auto immunity in the Ovarian Resistance Syndrome: research and methodology development; Autoinmunidad en el Sindrome de Resistencia Ovarica: investigacion y desarrollo de metodologia

    Energy Technology Data Exchange (ETDEWEB)

    Oliver, P; Balter, H; Robles, A

    1998-07-01

    de receptores en el material biologico empleado mediante graficos de Scatchard. En cuanto al control de calidad, se selecciona el estudio de la maxima capacidad de union del ligando al receptor, como uno de los parametros que mayor informacion brinda sobre la performance del mismo. La validacion clinica se efectuo mediante la utilizacion de inmunoglobulinas aisladas a partir del suero de donantes sanos considerados como centrales negativos y de mujeres con SRO confirmada por estudios efectuados en el exterior consideradas como centrales positivas. Todo esto, proporciona el desarrollo de un metodo cualitativo confiable sensible y especifico para la determinacion de anticuerpos antireceptor de FSH de inmediata aplicacion en el area de la salud humana en nuestro medio.

  7. Burner redesign for the reduction of the unburned particulate emission in thermal power stations of Comision Federal de Electricidad; Rediseno de quemadores para la reduccion de la emision de particulas inquemadas en centrales termicas de la Comisionon Federal de Electricidad

    Energy Technology Data Exchange (ETDEWEB)

    Huerta Espino, Mario; Espipnoza Garza, Jesus; Mani Gonzalez, Alejandro; Giles Alarcon, Armando; Pena Garcia, Adriana; Albarran Sanchez, Irma L; Mendez Aranda, Angel [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    2001-07-01

    generadores de vapor de la CFE. Asi como se muestran graficas de los contornos de la zona de recirculacion generada por cada difusor sin combustion y una figura del perfil de velocidades que se genera frente al difusor. De acuerdo con los resultados obtenidos en la evaluacion aerodinamica de quemadores frontales de flujo rotacional, se puede establecer que las caracteristicas de la zona de recirculacion, generada por este tipo de quemadores, se relacionan con parametros geometricos del difusor que se identifican con el numero de giro y la caida de presion, donde es necesario buscar disenos que mejoren las condiciones del proceso de mezclado y combustion en el quemador.

  8. Excited cooper pairs

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Arrietea, M. G.; Solis, M. A.; De Llano, M. [Universidad Nacional Autonoma de Mexico, Mexico, D.F (Mexico)

    2001-02-01

    alrededor del 70% para parametros tipicos de cupratos superconductores cuasi-bidimensionales.

  9. Heat transfer in simple houses; Transferencia de calor en casas habitacion

    Energy Technology Data Exchange (ETDEWEB)

    Porta, Miguel Angel; Rubio, Eduardo; Fernandez, Jose Luis [Centro de Investigaciones Biologicas del Noroeste, Baja California Sur, (Mexico); Gomez Munoz, Victor [Centro Interdiciplinario de Ciencias Marinas, Baja California Sur (Mexico)

    2000-07-01

    A lumped parameter model is used to represent, with a high degree of precision, the temperature and comfort evolution with the time of a simple house, under any hot, extreme weather variation. Results are validated by experimental work in physical models, built to scale 1:2, with materials and building techniques typical of social interest housing in Baja California, Mexico. With the mathematical model properly calibrated, adequately validated heat transfer coefficients between walls, ceiling and windows are calculated. Sensitivity analyses lead to values of heat loads in simple houses with varying shapes, orientation, shading devices, and construction materials and techniques. Energy balance in the present work is achieved by means of three simultaneous equations, each depicting energy equilibrium in one of the basic building elements: the window glazing, the building materials, and inside air. Simultaneous solution of the equations is accomplished with of the Kutta method, which yields the representative temperature along the day of each of the components, while heat flow among them is calculated, together with thermal exchange with the environment. Comfort levels, energy consumption and saving are hence easily derived, and the economical pertinence of passive elements can be evaluated. [Spanish] Este trabajo presenta un modelo matematico de parametros concentrados que representa, de manera apropiada, el comportamiento de una casa habitacion tipica a lo largo de un dia cualquiera. Los resultados se validan mediante la experimentacion en modelo fisico, donde se ensayan casetas de material y dimensiones similares a las casas de interes social, a escala 1:2. Una vez que se ha calibrado el modelo, se pueden determinar, mediante corridas apropiadas en computadora, los coeficientes especificos de transferencia de calor en muros, ventanas y techo. Los analisis subsecuentes de sensibilidad producen informacion util para conocer los requerimientos energeticos de cada casa

  10. Study of the Fixation and Migration of Radioactive Cations in a Natural Ion Exchanger; Etude de la Fixation et de la Migration de Cations Radioactifs dans un Echangeur d'Ions Naturel; 0418 0417 0423 0427 0415 0414 ; Estudio de la Fijacion y de la Migracion de Cationes Radiactivos en un Cambiador Natural de Iones

    Energy Technology Data Exchange (ETDEWEB)

    Baetsle, L. [Centre d' Etudes de l' Energie Nucleaire, Mol (Belgium)

    1960-07-01

    With a view to utilizing lignite as a natural ion exchanger in the treatment of radioactive waste, a study was made of its physical and physico-chemical properties with reference to ion exchange. The distribution of Sr{sup 90} and Cs{sup 137} ions in the presence of Ca, Na and H was first examined and the equilibrium constants calculated. The kinetics and fixation of ions were then studied, and various parameters required for the calculation of ion-exchange beds were established. Study of the complex phenomenon of radioactive ion migration in the soil was started by the separate investigation of each component ionic equilibrium. (author) [French] Afin d'utiliser le lignite comme echangeur d'ions naturel dans le traitement d'eaux residuaires radioactives, uene etude a ete faite de ses proprietes physiques et physiochimiques, ayant trait a l'echange d'ions. En premier lieu on a etudie la distribution des ions {sup 90}Sr et {sup 137}Cs en presence de Ca, Na et H, et calcule les constantes d'equilibre. En second heu on a traite la cinetique de la fixation des ions, et etabli quelques parametres necessaires au calcul de hts d'echangeurs d'ions. L'etude du phenomene complexe de la migration des ions radioactifs dans le sol a ete abordee par l 'investigation separee de chacun des equilibres ioniques composants. (author) [Spanish] Con objeto de utilizar el lignito como cambiador natural de iones en el tratamiento de aguas residuales radiactivas, se han estudiado sus propiedades fisicas y fisicoquimicas en relacion con el intercambio de iones. En primer lugar, el autor ha estudiado la distribucion de los iones {sup 90}Sr y {sup 137}Cs en presencia de Ca, Na y H, y ha calculado las constantes de equilibrio. En segundo lugar ha estudiado la cinetica de la fijacion de iones y ha establecido algunos parametros necesarios para calcular los lechos de cambiadores de iones. El autor ha abordado el estudio del complejo fenomeno de la migracion de iones radiactivos en el suelo

  11. Application of heating in dex in Los Humeros geothermal reservoir; Comportamiento de los indices de calentamiento en el yacimiento geotermico de los Humeros

    Energy Technology Data Exchange (ETDEWEB)

    Aragon, Alfonso; Arellano, Victor M; Izquierdo, Georgina; Garcia, Alfonso; Barragan, Rosa Maria; Verma, Mahendra P [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico); Pizano, Arturo [Comision Federal de Electricidad, Los Humeros (Mexico)

    2000-12-01

    Reservoir engineering uses several methodologies to evaluate reservoir information characteristics, which in one well vary with time during its production life. One of the methods widely used is the pressure analysis by stimulating the reservoir through cold water injection. For this case, the temperature is used as stimulating parameter and the resultant perturbation is analyzed for the formation intervals in order to determine reservoir permeability and thickness. This method requires a set of temperature logs taking a different stability time. The heating index is calculated from the temperature gradient with time. The index correlated with drilling parameters such as the circulation lost volume, lithology, drilling speed, et cetera. It is used identify interesting reservoir characteristics for production and injections purposes. The method is applied on wells: Br-2 from Broadlands, New Zealand; and H-11, H-31 and H-33 from Los Humeros, Mexico. The results indicate the usefulness of this method in evaluating geothermal reservoirs. [Spanish] La ingenieria de yacimientos dispone de diversas tecnicas para la evaluacion de las caracteristicas de los espesores de la formacion en un pozo, cuyo comportamiento cambia a largo de las diferentes etapas de su vida productiva. Uno de los metodos ampliamente utilizados es el comportamiento de la presion a traves de estimulos suministrados al yacimiento. Haciendo una analogia de la presion, para el caso de inyeccion de agua fria, se utiliza la temperatura como estimulo y se analizan los disturbios que esta provoca en algunas secciones de la formacion, a partir de lo cual es factible determinar intervalos permeables en el yacimiento. El metodo requiere de un par de perfiles de temperatura registrados a diferente tiempo de reposo del pozo. Con las diferencias de temperatura respecto al tiempo, se calcula el indice de calentamiento el cual se correlaciona con los parametros disponibles, contenidos durante la perforacion, como son

  12. Fuzzy controller of speed-power of a synchronous micro generator; Controlador difuso de velocidad-potencia de un microgenerador sincrono

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Alvarado, Raziel

    2002-11-01

    This thesis shows the design and implementation of a speed-power fuzzy-logic controller. The controller implementation was carried out on the Schrage motor-synchronous generator set. The synchronous alternator is rated 7 kVA, 220 V, 1800 rpm, 60 Hz. Two PI like fuzzy-logic controllers were developed with 9 and 25 rules. The controllers use the speed or power error and its integral as input variables and as an output the control signal from the brush-positioner of the Schrage motor. At the controller design stage, the anfis (adaptive-network-based fuzzy inference system) learning and structure procedure was used for tuning up parameters of the membership functions used on the designed fuzzy controllers. These controllers are first-order Sugeno-type. The designed controllers were tested on the motor-generator set under loaded and no-loaded conditions. It was found that PI-9 rules fuzzy-logic controller had better performance on both operating conditions. [Spanish] En este trabajo de tesis se presenta el diseno e implementacion de un controlador difuso de velocidad-potencia, para un grupo motor Schrage-generador sincrono de 7 kVA, 220 V, 1800 rpm, 60 Hz. Se implementaron controladores difusos del tipo PI de 9 y 25 reglas. Estos controladores utilizan como variables de entrada el error y la integral del error, de velocidad o potencia segun corresponda, y como variable de salida la senal de control del posicionador de las escobillas del motor Schrage. En la etapa de diseno de los controladores, se utilizo la estructura y el procedimiento de aprendizaje anfis (Sistema de Inferencia Difuso Basado en Redes Adaptables, por sus siglas en ingles) para sintonizar los parametros de las funciones de membresia de los controladores difusos, los cuales son del tipo Sugeno de primer orden. Con la finalidad de validar los controladores disenados, se realizaron pruebas experimentales al grupo motor-generador en condiciones de vacio y carga. Se encontro que el controlador difuso tipo

  13. Il disegno gotico di San Giovanni Valdarno

    Directory of Open Access Journals (Sweden)

    Maria Teresa Bartoli

    2017-12-01

    Full Text Available San Giovanni Valdarno è una città del Valdarno di Sopra, il cui attuale centro storico fu la prima delle terre nuove della Repubblica Fiorentina, fondata alla fine del XIII secolo. Le vicende storiche della trasformazione del nucleo murato originario sono state oggetto di molti studi, ma la logica del suo particolare disegno non è stata molto investigata. L’approccio archeologico è quindi giustificato dal fatto che, per ciò che riguarda la forma del progetto urbano originario, gli studi finora pubblicati non vanno molto oltre la definizione di «progettazione ortogonale», data da David Friedman, suo maggiore studioso. I giudizi su di essa si sono quindi attestati sulla generica attribuzione di virtù e difetti che la tradizione storiografica annette alla città medievale, applicando formule basate su paradigmi convenzionali.Volendo condurre la ricerca di una descrizione significativa del tessuto materiale della città attingendo a paradigmi appartenenti al momento della sua realizzazione, è stato condotto uno studio metrico sulla forma della città storica, con riferimento al sistema del braccio fiorentino, considerato come parametro di riferimento fondamentale per la comprensione di un manufatto di dimensione urbana. L’aspetto archeologico della ricerca consiste quindi nella ricostruzione complessa di un paradigma dimenticato dall’attuale tradizione storiografica, alla luce del quale emergono negli oggetti storici significati e valori caduti dalla memoria trasmessa.L’analisi, condotta sulla planimetria digitale con il supporto di documenti storici del ‘200 e del ‘500, ha fatto emergere l’ordine logico e continuo del disegno geometrico della città fondata, replicabile a mente (e perciò memorabile, messo in opera nella pianta urbana, rendendo esplicita la sua logica e le sue connessioni sia con la cultura scientifica del tempo, sia con la tradizione storica precedente, risalendo a Vitruvio. Ai fini di interpretare

  14. The SLIMITRE system: T-P-CCL registry in high temperature oil wells; El sistema SLIMITRE: registro T-P-CCL en pozos petroleros de alta temperatura

    Energy Technology Data Exchange (ETDEWEB)

    Iglesias R, Eduardo and others [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2001-07-01

    las secciones que siguen se presentan los principales parametros de diseno, se explica la arquitectura del sistema, se describen las herramientas y el subsistema de adquisicion de datos; se exponen los resultados obtenidos y se presentan las conclusiones.

  15. Opioid system manipulation during testicular development: results on sperm production and sertoli cells population = Manipulação do sistema opioidérgico durante o desenvolvimento testicular: consequência sobre a produção espermática e a população de células de sertoli

    Directory of Open Access Journals (Sweden)

    Fernanda Mafra Cajú

    2011-04-01

    Full Text Available The Sertoli cell has fundamental importance to the development andmaintenance of spermatogenesis, as well as it has a directly proportional numerical relationship to sperm production. The proliferative period of this cell in rats occurs between 13 days pre-natal and 21 days pos-natal, when is established the final population in adult animals. The Leydig cell can modulate the Sertoli cell proliferation during fetal and neonatal periodƒn throughƒnƒnƒÒ-endorphin. The manipulation of opioidergic system can promote changes in parameters related to development of nervous, endocrine andreproductive systems. By the way, the main purpose of this present work was to compare the effects of the blockade of opioid receptor blocking in Sertoli cells using naltrexone (50 mg kg-1 during fetal and neonatal period in Wistar rats. According to the results, themanipulation of opioidergic system during pre-natal period reduced the total length of seminiferous tubule and Sertoli cell population in adult rats, but sperm production was normal because this cell has had a compensatory response for spermatozoids support capacity.As celulas de Sertoli tem fundamental importancia para o desenvolvimento e manutencao da espermatogenese, bem como possuem uma relacao numerica diretamente proporcional com a producao espermatica. O periodo proliferativo destas celulas em ratos ocorre entre 13 dias pre-natal e 21 dias pos-natal, resultando na definicao da populacao decelulas de Sertoli nos animais adultos. As celulas de Leydig podem modular a proliferacao das celulas de Sertoli durante o periodo fetal e neonatal por meio da ƒÒ-endorfina. A manipulacao do sistema opioidergico durante esta fase pode promover alteracoes em parametros relacionados com o desenvolvimento dos sistemas nervoso, endocrino ereprodutivo. Em virtude disto, o objetivo do presente trabalho foi comparar os efeitos do bloqueio de receptores opioides nas celulas de Sertoli, utilizando o naltrexone (50 mg kg

  16. Development of applications in Internet for the calculation of solar control devices; Desarrollo de una aplicacion en Internet para el calculo de dispositivos de control solar

    Energy Technology Data Exchange (ETDEWEB)

    Perez V, Jesus B; Robles G, Saul; Villa M, Hector A; Cabanillas L, Rafael E [Universidad de Sonora, Hermosillo, Sonora (Mexico)

    2000-07-01

    In this work the development of an interactive software, visible over the World Wide Web, is presented to support the basic calculation required to control the solar gain inside buildings and houses. The site has two main parts: one part describes in a very required parameters to design devices for the control of the illumination inside the buildings, like overhangs and wingwalls for shading. The other part has the routines and procedures to calculate the sun position for any date and position over the earth, and the horizontal and vertical protection angles. The part to implement the calculations has been developed as a Java applet which can run on any platform and let the users, in an interactive way, to get the results. This software makes possible that any Internet user can run the application from his/her own computer without having to compile of use sophisticated procedures as it happens with traditional languages. With this web site it is intended to cover the necessity of having simple and reliable means for architects and civil engineers to support the use of solar energy and the saving of energy in bioclimatic design of buildings. [Spanish] En este trabajo se presenta el desarrollo de un sitio interactivo visible en el World Wide Web (WWW) que pretende servir de apoyo para los calculos basicos de control de asoleamiento en viviendas y edificios. El sitio esta conformado por dos partes principales: una parte cubre el aspecto informativo, donde en forma sencilla y clara, se explican los conceptos y parametros necesarios para disenar los dispositivos de control, alerones y parteluces. La otra parte contiene los procedimientos y las rutinas de calculo para la determinacion de la posicion solar para cualquier fecha del ano desde cualquier punto sobre la tierra, asi como los angulos de sombreado vertical y horizontal. Para la realizacion de los calculos se ha construido un applet de Java, el cual puede ejecutarse desde cualquier plataforma de computacion y

  17. APLICAÇÃO DE BIOPELÍCULAS PIGMENTADAS EM QUEIJO DE COALHO

    Directory of Open Access Journals (Sweden)

    Almeida Castro Pagani

    2013-03-01

    Full Text Available O queijo de coalho é um produto tipicamente nordestino e muito popular. É um queijo cuja tecnologia é relativamente simples e cuja fabricação não exige equipamentos sofisticados, o que torna a vida de prateleira curta, necessitando assim, do emprego de algum processo para preservar sua qualidade durante o armazenamento. Assim, o uso de revestimento comestível apresenta-se como uma ótima opção para melhorar a qualidade e aumentar o tempo de prateleira deste produto. O presente trabalho teve como objetivo estudar a influência da aplicação de revestimentos comestíveis no queijo coalho, com a finalidade de aumentar sua vida de prateleira. Para isso, foram realizados revestimentos em amostras de queijo de coalho com parafina fundida, pigmentada com 3% de açafrão, e com soluções alcoólicas formadas com 3% de açafrão (solução 1 e 3% de fucsina (solução 2. Sendo que, as amostras revestidas e amostras sem revestimento (amostras controle, foram armazenados durante cinco dias a ±4°C. Foram avaliados os parâmetros de pH, acidez titulável, atividade de água e umidade, nos tempos de armazenamento 0 e 5 dias, para todas as amostras. Além disso, foram realizadas análises microscópicas nas superfícies dos queijos revestidos, utilizando um microscópio digital, com aumento de 60x. Os dados dos parametros fisico-quimicos como o pH e atividade de água (aw das amostras revestidas e controle não apresentaram diferença estatística. Com relação a umidade observou-se uma diferença significativa entre as amostras e durante o período de armazenamento. As amostras revestidas com soluções alcoólicas de açafrão e fucsina apresentaram boa aderência ao produto, o que não foi observado nas amostras com revestimento parafinado.

  18. Pore structure and carbonation in blended lime-cement pastes

    Directory of Open Access Journals (Sweden)

    Álvarez, J. I.

    2006-06-01

    Full Text Available The present study aims to gain a fuller understandingof the curing process in lime pastes (100, 90, 80, 70,60, 50 and 40% lime blended with cement by analyzingcarbonation in these materials. A hydrated, airslaked lime powder and CEM II A/L 32.5 Portlandcement were used for the blends. These materialswere singled out for research primarily because theymay be used in the restoration of heritage monuments.Variation in weight was used as an indicator for carbonation.A new parameter, A, was found to vary inverselywith the percentage of the cement because of theprevalence of Knudsen diffusion in the paste, in turndue to the characteristics of the pore structure, whichwas studied by mercury intrusion porosimetry (MIP.The hygroscopic study conducted on the different pastesprovided information on water content at a givenhumidity and its location, i.e., adsorbed on the surfaceof the pores or condensed inside them, obstructing thediffusion of CO2. The conclusion drawn from this studyof the curing process was that neither drying nor C3Shydration retarded lime carbonation.En este trabajo se estudia el proceso de carbonatacionen pastas mixtas de cal y cemento (100, 90, 80, 70, 60,50 y 40% de cal con el objeto de obtener un mejorconocimiento del proceso de curado en estos materiales.Para ello se ha empleado una cal aerea hidratada en polvoy un cemento Portland del tipo CEM II A/L 32,5. Enparticular, este estudio investiga estos materiales ya quepueden ser utilizados en la restauracion del PatrimonioCultural. Se ha utilizado la variacion de peso como indicadordel proceso de carbonatacion. Se ha establecidoun nuevo parametro, A, que varia inversamente con elporcentaje de cemento en la pasta, debido al predominiode la difusion de Knudsen como consecuencia de laestructura porosa, que ha sido estudiada por medio deporosimetria de intrusion de mercurio (PIM. El estudiohigroscopico realizado sobre las diversas pastas permiteconocer el contenido en agua a una

  19. Application of a Lagrangian modeling to the atmospheric pollution; Aplicacion de una modelizacion Lagrangiana a la contaminacion atmosferica transfronteriza

    Energy Technology Data Exchange (ETDEWEB)

    Rua, A.; Hernandez, E. [Departamento de Fisica del Aire, Universidad Complutense de Madrid, Facultad de Ciencias Fisicas, Madrid (Spain); Gimeno, L. [Centro de Formacion del Instituto Nacional de Meteorologia (INM), Madrid (Spain)

    1998-04-01

    In this article, a physical modeling of the atmospheric pollution was considered. The objective was to determine the concentrations of pollutants in a receptor station reproducing the way followed by the air mass and simulating the physical and chemical processes involved during this way. To do that we used a Lagrangian model. To estimate the quality of the model a comparison between the theoretical concentration from the model and the observed concentrations is done. The model uses the air mass trajectories arriving at the receptor station calculated from the Limited Area Model (LAM). These trajectories let us know the air mass position each 6 hours. Once the initial model had been run, several parameters were modified with the aim of reproducing letter the conditions of The Iberian Peninsula. The considered pollutants were the SO{sub 2} and SO{sub 4}{sup 2}- and the chosen station was Logrono (Spain). [Spanish] En este articulo se planteo una modelizacion de la contaminacion atmosferica transfronteriza desde un punto de vista fisico. Asi, reproduciendo el camino seguido por las masas de aire que transportan los contaminantes y simulando lo mejor posible los procesos fisico-quimicos existentes durante ese camino, pretendimos determinar cual fue la concentracion final registrada de tales contaminantes en una estacion receptora. Un modelo fisico de tipo Lagrangiano se uso en este trabajo. Para estimar la bondad de tal modelizacion se realizo una comparacion entre la concentracion final estimada mediante la modelizacion y la observada. Se partio de las trayectorias de las masas de aire que llegan hasta esa estacion receptora, calculadas a partir del Modelo de Area Limitada (LAM), y que permite conocer la posicion de la masa de aire cada 6 horas. Fueron modificados algunos parametros del modelo fisico inicialmente propuestos, adecuandolos mas a la realidad fisica de la Peninsula Iberica, lograndose una mejora en los resultados obtenidos en un primer momento. Los

  20. Historical-statistical analysis of energy consumption in energy management; Analisis historico-estadistico del consumo energetico en la administracion de energia

    Energy Technology Data Exchange (ETDEWEB)

    Guizar Bejarano, Ruben [IMENOR (Mexico); Oven, Mark [RCG/Hagler, Bailly, Inc., Washington (United States)

    1992-12-31

    Traditionally the specific consumption of energy has been considered as the most adequate index to evaluate the efficiencies in the productive processes. Nevertheless, this index, in some instances is highly susceptible to suffer significant variations, due to factors such as equipment condition, raw materials quality, operational parameters, climate and production level. This last one definitely is the most important and requires a deeper analysis. In this presentation a methodology is developed to analyze the energy consumption as well as their specific energy consumption with respect to production. Enough historical data are utilized to allow for a statistical analysis. This study is of equal usefulness in an energy diagnosis, as in a management program of energy saving. In presenting the possibility of identifying potential energy saving, stands out the advantages of the analysis and the conclusions that can be derived from it. Through the actual data collected in several industries during the energy diagnosis, various possible results of the analysis are presented. Finally, how this type of analysis can be adapted to a more precise control of the energy consumption is described and be used as a base for establishing goals in energy efficiency in the long term. [Espanol] Tradicionalmente se ha considerado al consumo especifico de energia como el indice energetico mas adecuado para evaluar las eficiencias de los procesos productivos. Sin embargo, este indice es en ocasiones altamente susceptible a sufrir variaciones importantes, debido a factores como el estado de los equipos, la calidad de la materia prima, los parametros operativos, el clima, y el nivel de produccion. Este ultimo es decididamente el mas importante, y requiere un analisis mas profundo. En esta presentacion se desarrolla una metodologia para analizar tanto consumos de energia como consumos especificos de energia con respecto a la produccion. Se utilizan suficientes datos historicos para permitir

  1. Preparation of hydrotalcite compounds using ultrasound irradiation to capture CO{sub 2}; Preparacion de compuestos tipo hidrotalcita utilizando irradiacion de ultrasonido para la captura de CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, J.A.J.; Paredes, S.P.; Valenzuela, M.A.; Hernandez, M.L. [Instituto Politecnico Nacional, ESIQIE, Mexico, D.F. (Mexico)]. E-mail: sparedesc@ipn.com.mx

    2009-09-15

    Al-Mg hydrotalcite compounds (HTC) were prepared using co-precipitation, sol-gel and reconstruction of the structure with ultrasound-assisted irradiation. The interlaminar components for each method were nitrate, acetylacetonate ethoxide and metavanadate, respectively. Optimization of the synthesis was performed using x-ray diffraction. The effect of the different parameters on synthesis was studied, including pH, time and ultrasound irradiation power. In addition, for the reconstruction method, temperature and calcination time were evaluated. For all methods, ultrasound-assisted methods were found to be more efficient and economical than conventional methods reported (autoclave). They also have the advantage of being able to control properties such as crystallinity, porosity and the specific surface, which significantly depends on the preparation method, irradiation time and type of interlaminar component. These methods are intended to synthesize interlaminar anionic materials that are very scarce in nature with better properties than traditional adsorbents used for the capture of CO{sub 2}. [Spanish] Se prepararon compuestos tipo hidrotalcita Al-Mg por los metodos de: coprecipitacion, sol gel y reconstruccion de la estructura asistidos por irradiacion de ultrasonido. Los componentes interlaminares para cada metodo fueron respectivamente: nitrato, etoxido-acetilacetonato y metavanadato. La optimizacion de la sintesis, se efectuo mediante difraccion de rayos-X. Se estudio el efecto de diversos parametros en la sintesis: pH, tiempo y potencia de irradiacion de ultrasonido, ademas, para el metodo de reconstruccion se evaluaron la temperatura y el tiempo de calcinacion. En todos los casos se encontro que el empleo de metodos asistidos por ultrasonido resultan ser mas eficientes y economicos que los metodos convencionales reportados (autoclave), ademas tienen la ventaja, de poder controlar propiedades tales como: la cristalinidad, la porosidad y la superficie

  2. Training resources in renewable energy: study and evaluation; Recursos de capacitacion en energia renovable: estudio y evaluacion

    Energy Technology Data Exchange (ETDEWEB)

    De Buen Rodriguez, Odon [Energia, Tecnologia y Educacion, S.C., ENTE, S.C. (Mexico)

    2010-07-01

    The report herein describes the results of an evaluation process carried out to identify, document and analyze teaching and training capacities in the field of renewable energy for those who participate in the development, acquisition, installation, inspection and operation and maintenance of small- and large-scale wind, photovoltaic and solar water heating systems in North America. The document is divided into four sections. Chapter 1 presents the results of the evaluation process, expressed according to different parameters, as well as some of the significant findings. Chapter 2 responds to several questions related to difficulties, challenges, opportunities for improvement and recommendations, with a trilateral perspective. Chapter 3 evaluates the three technologies that are the focus of this study: photovoltaic, wind and solar heat. Chapter 4 describes the knowledge needed by those who professionally work in activities related to the three technologies mentioned, as well as their institutional context. The list of courses identified through this evaluation process are available on the CCA website, at www.cec.org/cursosenergia. [Spanish] El presente informe describe los resultados de un proceso de evaluacion llevado a cabo para identificar, documentar y analizar las capacidades en materia de ensenanza y capacitacion en energia renovable de quienes participan en la elaboracion, adquisicion, instalacion, inspeccion y operacion y mantenimiento de sistemas eolicos, fotovoltaicos y de calentamiento solar de agua -tanto pequenos como de gran escala-, en America del Norte. El documento se divide en cuatro partes. El capitulo 1 presenta los resultados del proceso de evaluacion, expresandolos en funcion de diferentes parametros, asi como ciertos hallazgos importantes. El capitulo 2 responde a diversas preguntas relativas a las dificultades, retos, oportunidades de mejoramiento y recomendaciones, con una perspectiva trilateral. El capitulo 3 evalua las tres tecnologias

  3. Experimental numerical study utilizing CFD in a stratified gasifier operating with biomass; Estudio numerico experimental de un gasificador estratificado que opera con biomasa, utilizando CFD

    Energy Technology Data Exchange (ETDEWEB)

    Rogel Ramirez, Alejandro

    2007-07-01

    utilizado para predecir perfiles de temperatura, composicion del gas, poder calorifico del syngas, eficiencia en la conversion del carbon y el comportamiento del reactor cuando los parametros de operacion y las propiedades de la alimentacion son cambiadas. El modelo estandar de turbulencia {kappa}-{epsilon} y el modelo RNG {kappa}-{epsilon}, se utilizan para la simulacion del flujo turbulento.

  4. The Measurement of Reactivity In Multiregion Subcritical Systems by the Pulsed Neutron Technique; Mesure de la Reactivite dans les Systemes Sous-Critiques a Plusieurs Regions par la Methode des Neutrons Pulses; Izmerenie reaktivnosti v mnogozonnykh podkriticheskikh sistemakh metodom impul'snykh nejtronov; Mediciones de la Reactividad en Sistemas Subcriticos de Varias Regiones Mediante la Tecnica de los Neutrones Pulsados

    Energy Technology Data Exchange (ETDEWEB)

    Sherwin, J.; Leng, J. H. [United Kingdom Atomic Energy Authority, Windscale Works, Cumberland (United Kingdom)

    1965-10-15

    les resultats des methodes classiques de determination de la reactivite, ns discutent les methodes experimentales utilisees et les difficultes rencontrees dans les systemes ralentis au graphite. (author) [Spanish] Los autores estudian el decrecimiento inmediato de una rafaga de neutrones termalizados en un sistema subcritico de varias regiones, empleando una teoria de difusion de dos grupos. Demuestran que es posible establecer una relacion entre la constante de decrecimiento inmediato del modo fundamental y el factor de multiplicacion efectiva del sistema eligiendo dos parametros que, para los fines de la presente memoria se definen como el coeficiente de respuesta del reactor y como la correccion del decrecimiento inmediato, los cuales dependen en gran medida de la distribucion espacial del flujo en el interior del sistema. En el caso de un sistema uniforme desprovisto de reflector, el coeficiente de respuesta puede identificarse con la vida media de los neutrones en el sistema; en el caso de un sistema de varias regiones, ese coeficiente representa una combinacion de la vida media de los neutrones en cada region, ponderada por integrales del tipo de perturbacion. En cuanto al segundo parametro - la correccion del decrecimiento-, puede carecer de significado material en el sentido de que deriva de un intento de relacionar las dos escalas de reactividad que intervienen en el problema, es decir, la escala obtenida con la constante de decrecimiento inmediato y la escala obtenida empleando el factor de multiplicacion efectiva. Los autores examinan las propiedades de estos parametros en el caso de un reactor de uranio enriquecido moderado con grafito y constituido por un cuerpo y un reflector uniformes, y ponen de manifiesto que les dos parametros no quedan definidos unicamente por la reactividad del sistema, sino que dependen del metodo elegido para hacer que el sistema resulte subcritico. Los autores tratan por metodos teoricos dos conjuntos de mediciones. Uno de ellos

  5. Chemical Effects of Nuclear Recoil in Organic Halide Systems: A New Theoretical Treatment and Experimental Verification of the Theory; Effets Chimiques du Recul Nucleaire dans des Systemes Organiques Halogenes: Nouveau Traitement Theorique et Verification Experimentale de la Theorie; Khimicheskie vozdejstviya yadernoj otdachi v organicheskikh galoidnykh sistemakh: novoe teoreticheskoe tolkovanie i ehksperimental'noe podtverzhdenie teorii; Efectos Quimicos del Retroceso Nuclear en Sistemas de Haluros Organicos: Nuevo Tratamiento Teorico y Verificacion Experimental de la Teoria

    Energy Technology Data Exchange (ETDEWEB)

    Kontis, S. S.; Sanitwongs, P.; Weston, M. [Londonderry Laboratory for Radiochemistry, University of Durham, Durham (United Kingdom)

    1965-04-15

    calientes; la retencion se expresa en funcion de dos tipos de parametros, a saber: 1) la probabilidad relativa de que ei choque de un atomo caliente de halogeno radiactivo con una molecula determinada produzca la retencion del atomo caliente en dicha molecula; 2) los limites energeticos superior e inferior dentro de los cuales el atomo de bromo puede considerarse caliente. Los autores demuestran como el primer tipo de parametro puede deducirse experimentalmente de mezclas binarias de un haluro organico y el correspondiente halogeno libre; el segundo tipo de parametro debe deducirse a partir de datos nucleares quimicos. Dichos metodos han sido ensayados en los sistemas C{sub 2}H{sub 5}Br/CCl{sub 4}/Br{sub 2} and C{sub 2}H{sub 5}Br/C{sub 6}H{sub 5}Br/Br{sub 2}. Los valores calculados para las retenciones (empleando parametros derivados del estudio de los sistemas C{sub 2}H{sub 5}Br/Br{sub 2}, CCl{sub 4}/Br{sub 2} and C{sub 6}H{sub 5}Br/Br{sub 2})) eoncuerdan satisfactoriamente con los dalos hallados experimentalmeme en mezclas cuya fraccion molar de bromo es superior a 0,1. De esta manera se considera que el mecanismo propuesto por Libby permite explicar las retenciones organicas observadas en dichas mezclas. Cuando la fraccion molar de bromo se va reduciendo a valores inferiores a 0,1, las retenciones observadas se hacen progresivamente mayores que los valores calculados. Este fenomeno se atribuye a la existencia de otros modos de marcacion con atomos calientes, que entran en juego cuando la concentracion de bromo no es bastante elevada para eliminar adecuadamente los radicales en virtud de mecanismos de depuracion. (author) [Russian] Byli razrabotany metody rascheta organicheskogo uderzhanija radiogalogenov, kotorye mozhno ozhidat' vsledstvie nejtronnoj aktivacii smesej dvuh organicheskih galoidov i sootvetstvujushhih svobodnyh galogenov. Jeti metody osnovany na koncepcijah processa ''bil'jardnogo shara'' Libbi po mecheniju gorjachih atomov, i uderzhanija vyrazhajutsja v

  6. CFD modelling of an open core downdraft moving bed biomass gasifier; Modelado de un gasificador estratificado de lecho movil de biomasa, utilizando CFD

    Energy Technology Data Exchange (ETDEWEB)

    Rogel-Ramirez, A [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)]. E-mail: ARogelR@iingen.unam.mx

    2008-10-15

    las reacciones heterogeneas entre el carbon activo y O{sub 2}, CO{sub 2} y H{sub 2}O. El efecto de la turbulencia en la fase gaseosa se determina usando el modelo {kappa}-{epsilon}. El modelo proporciona informacion de la composicion del gas, velocidades y temperaturas de salida y el comportamiento del reactor, y permite cambiar los parametros de operacion, y las propiedades de la alimentacion. Finalmente, se comparan los valores predichos por el modelo con datos disponibles en la literatura, mostrando congruencia satisfactoria desde un punto de vista cualitativo.

  7. Photo and cathode luminescence emission in oxide silicium films implanted with silicium; Emision de foto y catodoluminiscencia en peliculas de oxido de silicio termico implantadas con silicio

    Energy Technology Data Exchange (ETDEWEB)

    Flores, F; Aceves, M. [Instituto Nacional de Astrofisica Optica y Electronica, Mexico, D.F. (Mexico); Carrillo, J. [Benemrita Universidad Autonoma de Puebla, Puebla (Mexico); Dominguez, C. [Universida Autonoma de Barcelona, Barcelona (Spain); Falcony, C. [Instituto Politecnico Nacional, Mexico, D.F. (Mexico)

    2001-10-01

    disminucion en intensidad. Las peliculas de dosis alta tienen una banda centrada en 1.7 eV (banda A) y su intensidad se incrementa con los tratamientos termicos. Las bandas de catodoluminiscencia en todos los casos estan en 2.7 eV (banda D) y presentan cambios con los tratamientos termicos que parecen depender de la variacion en los parametros de implantacion.

  8. Steady state analysis and Eastern power system dynamic PDVSA EyP considering incorporating Furrial and PIGAP II generation plants; Analisis en regimen permanente y dinamico del sistema electrico de PDVSA EyP Oriente considerando la incorporacion de las plantas de generacion Furrial y PIGAP II

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, S [Universidad Nacional Experimental Politecnica, Antonio Jose de Sucre, Guayana, Bolivar (Venezuela)]. E-mail: sergiodrg200@gmail.com; Vasquez, C [Petroleos de Venezuela S.A., Maturin, Monagas (Venezuela)]. E-mail: vasquezcp@pdvsa.com

    2013-03-15

    Sector Electrico Nacional. Para el estudio de arranque de motores se determino el modelo dinamico del motor mayor mediante la estimacion de los parametros de su circuito equivalente, asi como la aplicacion del metodo de regresion no lineal para obtener el modelo de la carga partiendo de los datos caracteristicos suministrados por el fabricante.

  9. Prenatal irradiation: radioinduced apoptosis in developing central nervous system; Irradiacion prenatal: apoptosis radioinducida en el sistema nervioso central en desarrollo

    Energy Technology Data Exchange (ETDEWEB)

    Gisone, P; Dubner, D; Michelin, S; Perez, M R [Autoridad Regulatoria Nuclear, Buenos Aires (Argentina); Barboza, M [Hospital de Clinicas Jose de San Martin, Buenos Aires (Argentina)

    1998-07-01

    produccion de apoptosis en un modelo experimental de irradiacion prenatal. Se irradiaron cultivos primarios de cerebro (rata Wistar, dia 15 de e.g.), en un rango de dosis hasta 2 Gy (Cobalto 60). Se evaluo la respuesta a la incubacion con distintos neuroprotectores. Se estudiaron los siguientes parametros: alteraciones de la morfologia celular, fragmentacion de cromatina y fraccion de celulas apoptoticas. Las celulas irradiadas mostraron condensacion nuclear con presencia de cuerpos apoptoticos. Las corridas electroforeticas evidenciaron un patron de fragmentacion caracteristico ('laddering') con aumento dosis-dependiente en la fraccion de celulas apoptoticas analizadas por citometria de flujo. La incubacion con neuroprotectores no indujo cambios significativos en las concentraciones y los tiempos ensayados. Se analizan los resultados obtenidos. Se discute acerca del rol de la apoptosis, su relacion con la injuria oxidativa y los fenomenos de excitotoxicidad como mecanismo de danio radioinducido en el sistema nervioso central en desarrollo. (autor)

  10. Probability distribution of atmospheric pollutants: comparison among four methods for the determination of the log-normal distribution parameters; La distribuzione di probabilita` degli inquinanti atmosferici: confronto tra quattro metodi per la determinazione dei parametri della distribuzione log-normale

    Energy Technology Data Exchange (ETDEWEB)

    Bellasio, R [Enviroware s.r.l., Agrate Brianza, Milan (Italy). Centro Direzionale Colleoni; Lanzani, G; Ripamonti, M; Valore, M [Amministrazione Provinciale, Como (Italy)

    1998-04-01

    This work illustrates the possibility to interpolate the measured concentrations of CO, NO, NO{sub 2}, O{sub 3}, SO{sub 2} during one year (1995) at the 13 stations of the air quality monitoring station network of the Provinces of Como and Lecco (Italy) by means of a log-normal distribution. Particular attention was given in choosing the method for the determination of the log-normal distribution parameters among four possible methods: I natural, II percentiles, III moments, IV maximum likelihood. In order to evaluate the goodness of fit a ranking procedure was carried out over the values of four indices: absolute deviation, weighted absolute deviation, Kolmogorov-Smirnov index and Cramer-von Mises-Smirnov index. The capability of the log-normal distribution to fit the measured data is then discussed as a function of the pollutant and of the monitoring station. Finally an example of application is given: the effect of an emission reduction strategy in Lombardy Region (the so called `bollino blu`) is evaluated using a log-normal distribution. [Italiano] In questo lavoro si discute la possibilita` di interpolare le concentrazioni misurate di CO, NO, NO{sub 2}, O{sub 3}, SO{sub 2} durante un anno solare (il 1995) nelle 13 stazioni della Rete di Rilevamento della qualita` dell`aria delle Provincie di Como e di Lecco mediante una funzione log-normale. In particolare si discute quale metodo e` meglio usare per l`individuazione dei 2 parametri caratteristici della log-normale, tra 4 teoreticamente possibili: I naturale, II dei percentili, III dei momenti, IV della massima verosimiglianza. Per valutare i risultati ottenuti si usano: la deviazione assoluta, la deviazione pesata, il parametro di Kolmogorov-Smirnov e quello di Cramer-von Mises-Smirnov effettuando un ranking tra i metodi in funzione degli inquinanti e della stazione di misura. Ancora in funzione degli inquinanti e delle diverse stazioni di misura si discute poi la capacita` della funzione log-normale di

  11. Absorbing materials of thin film for photovoltaic structures prepared by the process of pyrolytic spraying; Materiales absorbedores en pelicula delgada para estructuras fotovoltaicas preparados por el proceso de rocio pirolitico

    Energy Technology Data Exchange (ETDEWEB)

    Calixto Rodriguez, Manuela

    2006-11-15

    InS{sub 2}, SnS{sub 2} y SnS por la tecnica de rocio pirolitico. Se analizaron las propuestas estructurales, opticas y electricas de estas peliculas para determinar el conjunto de parametros de deposito con los cuales se obtienen las mejores propiedades fisicas para la aplicacion de las mismas en estructuras fotovoltaicas. Se encontro que la relacion molar en solucion de los compuestos de partida y la temperatura de deposito son los parametros dominantes en el proceso de crecimiento de las peliculas. Para el deposito de peliculas delgadas se sulfuro de indio se usaron acetato de indio y N, N-dimetil tiourea como compuestos precursores de In y S, respectivamente. Se obtuvieron peliculas policristalinas del compuesto In{sub 2}S{sub 3} empleando temperaturas de substrato, Ts, entre 400 y 450 grados centigrados, y soluciones de acetato de indio y N, N-dimetil tiourea con relaciones molares (In:S) de 1:8 y 1:1. La brecha de energia, Eg, de estas peliculas varia de 2.04 a 2.67 eV, y el valor de la conductividad en obscuridad, D, varia de 10-7 a 1 (cm)-1 en funcion de la relacion molar en solucion. Se encontro que las peliculas depositadas empleando una relacion molar de In:S 1:8 son de naturaleza intrinseca independientemente de Ts, mientras que las depositadas empleando una relacion molar de In:S =1:1 y Ts 400 grados Celsius poseen conductividad tipo-n. Empleando una relacion molar de In:S = 1:1 y Ts = 500 grados centigrados se obtiene el compuesto In{sub 2}O{sub 3} policristalino cuyas propiedades opticas y electricas son: Eg 3 eV y D=11 (cm)-1, con conductividad electrica tipo-n. Las peliculas depositadas empleando una relacion molar de In:S = 1:1 y Ts 450 grados centigrados son las que tienen las caracteristicas apropiadas para su uso como material tipo-n en estructuras fotovoltaicas (Eg=2 eV y D=1-1 com-1).

  12. Model to predict the flow of tracers in naturally fractured geothermal reservoirs; Modelo para predecir el flujo de trazadores en yacimientos geotermicos naturalmente fracturados

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez Sabag, Jetzabeth

    1988-02-01

    {sub e1} fixes the characteristic of the family of curves. Also it was found that the irruption time for a given concentration depends strongly on {alpha}. [Spanish] El modelo propuesto ha sido desarrollado para estudiar el flujo de trazadores a traves de yacimientos geotermicos naturalmente fracturados. El sistema idealizado del yacimiento esta compuesto por dos regiones: Una region movil donde mecanismos de difusion y conveccion estan presentes y una region estancada o inmovil donde se consideran los mecanismos de difusion y adsorcion: en ambas regiones se considera la perdida de masa por decaimiento radioactivo. Las soluciones de las ecuaciones basicas de flujo estan en el espacio de Laplace y se utilizo el algoritmo de Stehfest para su inversion numerica. A pesar de la dispersion numerica que presentan estas soluciones, se encontro una tendencia bien definida para inferir el comportamiento del sistema bajo diferentes condiciones de flujo. Se encontro que, para propositos practicos el tamano de los bloques de matriz no tiene influencia sobre la respuesta de la concentracion, y la solucion se reduce a la presentada por Tang y asociados. Bajo estas condiciones, el comportamiento del sistema puede ser descrito por dos parametros adimensionales: El numero de Peclet en las fracturas y un parametro. Se derivo tambien la respuesta del trazador para la solucion pico. Se encontro una solucion analitica limite para el caso en que {alpha} tienda a cero, el cual corresponde al caso de un sistema homogeneo. Se comprobo que esta solucion limite es valida, para {alpha}<0.01. Para el caso de inyeccion continua esta solucion se reduce a la presentada por Coasts y Smith. Para la solucion pico, se encontro que el tiempo de irrupcion correspondiente a la maxima concentracion esta relacionada directamente con el grupo adimensional. Por lo tanto, es posible obtener el valor de P{sub e1} para una X{sub D} dada, o viceversa. Un grupo de graficas de concentracion adimensional en la fractura

  13. Some implications of time series analysis for describing climatologic conditions and for forecasting. An illustrative case: Veracruz, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Gay, C.; Estrada, F.; Conde, C. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)]. E:mail: feporrua@atmosfera.unam.mx

    2007-04-15

    series analysis. It is shown that sub-sample estimations can lead to an inaccurate estimation of the potential impacts of present climate variability and of climate change scenarios in terms of the probabilities of obtaining values outside a given coping range. [Spanish] La practica comun de utilizar submuestras de periodos de 30 anos de datos climatologicos para describir las condiciones pasadas, presentes y futuras ha sido ampliamente aplicada, en muchos casos sin considerar las propiedades de la serie de tiempo analizada. Este trabajo muestra que esta practica puede llevar, tanto a un uso ineficiente de la informacion contenida en los datos, como a una caracterizacion imprecisa de las condiciones climaticas actuales, y en particular de las futuras, debido a que los parametros son funcion del tiempo y del tamano de la submuestra. Mas aun, este enfoque puede llevar a la deteccion de cambios espurios en los parametros de la distribucion de la variable analizada. En este trabajo se utiliza el analisis de series de tiempo de las temperaturas mensuales observadas en Veracruz, Mexico, para ilustrar el hecho de que estas tecnicas permiten realizar una mejor descripcion de la media y variabilidad de las series, lo que a su vez permite (dependiendo de la clase de proceso) restringir la incertidumbre del pronostico, y por lo tanto ofrecer una mejor estimacion del riesgo presente y futuro de observar valores fuera de un rango de tolerancia dado. Los resultados presentados en este trabajo muestran que, si bien se encuentra una tendencia significativa en las temperaturas, aportando posible evidencia observada de cambio climatico en la region, no existe ninguna que apoye cambios en la variabilidad de dichas series, y por lo tanto tampoco existe ninguna evidencia observada a favor de que la variabilidad de la temperatura mensual aumentara o disminuira en el futuro. Esto es, si el cambio climatico ya esta ocurriendo, se ha manifestado como un cambio en la media de estos procesos y no

  14. Critical experiments and nuclear calculations - LAMPRE-I; Experiences critiques et calculs nucleaires concernant le LAMPRE-I; Kriticheskie opyty i yadernye raschety - LAMPRE-I; Experimentos criticos u calculos nucleares relativos al LAMPRE-I

    Energy Technology Data Exchange (ETDEWEB)

    Battat, M E [Los Alamos Scientific Laboratory, University of California, Los Alamos, NM (United States)

    1962-03-15

    utilise la methode S{sub n} pour resoudre le probleme du transport neutronique. La comparaison entre les valeurs calculees et les valeurs mesurees des parametres, tels que le coefficient thermique, l'efficacite des barres de controle et la masse critique, presente aussi de l'interet pour evaluer le degre de confiance que l'on peut accorder aux calculs des bureaux d'etudes. (author) [Spanish] Como parte de un programa de ensayos de combustibles de plutonio para reactores reproductores de neutrones rapidos, se ha construido y puesto en marcha en el Los Alamos Scientific Laboratory un reactor experimental de 1 MW refrigerado por sodio, cuyo cuerpo contiene una aleacion fundida de plutonio y hierro (90 atomos por ciento de Pu y 10 atomos por ciento de Fe; punto de fusion: 410 deg. C). La reactividad se regula por medio de un reflector de acero inoxidable y de cuatro barras de control de niquel situadas fuera del nucleo. Se han llevado a cabo experimentos a temperaturas (isotermicas) de 80, 160 y 480 deg. C en el cuerpo, a fin de determinar la masa critica y la eficacia del reflector a cada una de esas temperaturas. Tambien se midio la eficacia de las barras de control, por registro de los periodos y del coeficiente termico de la reactividad. Aplicando el metodo S{sub n} de resolucion del problema del transporte neutronico, se efectuaron calculos para determinar los parametros nucleares basicos del reactor. La comparacion entre los valores calculados y los valores medidos de parametros tales como el coeficiente termico, la eficacia de las barras de control y la masa critica, presenta tambien interes en lo que se refiere a la evaluacion del grado de confianza que puede atribuirse a los calculos del proyectista. (author) [Russian] V kachestve chasti programmy po razvitiyu plutonievogo topliva dlya reaktorov-razmnozhitele j na bystrykh nejtronakh Los-Alamosskaya nauchnaya laboratoriya skonstruirovala i ehkspluatiruet ispytatel'nyj reaktor s natrievym okhlazhdeniem moshchnost'yu v

  15. Behavior patterns of chemical and isotopic species (2006-2007) in the Los Azufres, Mich., geothermal field, as a response to reinjection; Patrones de comportamiento de especies quimicas e isotopicas (2006-2007) en el campo geotermico de Los Azufres, Mich., en respuesta a la reinyeccion

    Energy Technology Data Exchange (ETDEWEB)

    Barragan R, Rosa Maria; Arellano G, Victor Manuel; Martinez E, Ignacio; Aragon A, Alfonso [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: rmb@iie.org.mx; Reyes D, Lisette; Gonzalez, Rubi [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia de Los Azufres, Morelia, Michoacan (Mexico)

    2009-07-15

    quimicos e isotopicos ({delta}18 O y {delta}D) de fluidos de pozos del campo geotermico de Los Azufres, Mich., obtenidos en 2006 y 2007, para investigar los cambios ocurridos en sus patrones de comportamiento y su relacion con el proceso de reinyeccion de fluidos al yacimiento. El analisis de los datos comprendio las estimaciones de cloruros en las descargas totales, temperaturas de yacimiento, exceso de vapor en los fluidos de alimentacion, las concentraciones de CO{sub 2} en las descargas totales y en la fase liquida del yacimiento y las saturaciones de liquido en la formacion. Con los resultados se elaboraron mapas de isovalores de los parametros mencionados correspondientes a 2006 y 2007 para investigar su evolucion con respecto a los mapas obtenidos en 2005, asi como su relacion con las historias de reinyeccion. Se correlacionaron las composiciones isotopicas de los fluidos incluyendo los de reinyeccion para estimar efectos de mezcla de fluidos. Los resultados indican que las variables estudiadas responden a las tasas de reinyeccion en el campo. Las relaciones {delta}D vs {delta}18 O indican que un buen numero de pozos del campo producen diferentes proporciones de retornos de reinyeccion; en la zona norte los pozos AZ-65D, AZ-13, AZ-32, AZ-9A, AZ-9AD, AZ-28A, AZ-69D y AZ-44 producen una mayor proporcion mientras que los pozos AZ-5, AZ-28 y AZ-19 entre otros, producen una menor proporcion. En la zona sur los pozos AZ-2A, AZ-16AD, AZ-46 y AZ-33 producen relativamente altas proporciones de retornos de reinyeccion mientras que los pozos AZ-34, AZ-36 y AZ-37 producen menores proporciones. La distribucion de saturaciones de liquido hallada en 2007 muestra que las areas de maxima saturacion han disminuido con respecto a las distribuciones de este parametro en 2005 y 2006. En 2007 las saturaciones maximas de liquido se localizaron alrededor de los pozos AZ-22 y AZ-23 (zona sur) y AZ-28, AZ-32, AZ-45 y AZ-48 (zona norte), mientras que las saturaciones minimas se localizaron en

  16. Dynamics of the accumulation of polluting agents on transmission and distribution power line insulators; Dinamica de acumulacion de contaminantes sobre aisladores de lineas de transmision y distribucion

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Moreno, Felipe de Jesus

    1988-07-01

    , they are useful for the development of models that allow establishing the maintenance periods that, with a minimum cost, diminish in a substantial way the fault index of the national electrical system. [Spanish] El incremento en el uso de la electricidad y la necesidad de transferir grandes volumenes de energia en forma eficiente y segura, plantea la necesidad de buscar la disminucion de la frecuencia de fallas, asi como la optimacion de las lineas de transmision y distribucion. Para esto, el calculo de las distancias dielectricas requeridas en la etapa de diseno de lineas, solo podra lograrse a traves de un mejor conocimiento de los esfuerzos dielectricos producto de las sobretensiones de origen interno (maniobras de conexion) o externo (descargas atmosfericas) y la degradacion temporal o permanente, que introducen sobre los materiales aislantes los diversos factores ambientales y parametros meteorologicos (contaminacion humedad, temperatura, lluvia, etc.). De estos, la contaminacion es la causa de un alto porcentaje de fallas y el presente trabajo de tesis se relaciona con las contingencias originadas por este factor. Para hacer frente al problema, en Mexico se desarrolla un proyecto de investigacion en materia de contaminacion denominado Efectos de la Contaminacion en Aislamientos. Como parte de este proyecto, este trabajo de tesis analiza algunas hipotesis acerca de la dinamica de acumulacion de contaminantes en los aisladores, considerando los factores mas importantes en la evolucion del fenomeno de la contaminacion; a saber, los parametros meteorologicos, la morfologia del aislador y el periodo de exposicion al medio ambiente. En su estado actual, la investigacion en este campo en nuestro pais, asi como las herramientas de computo y bancos de informacion del proyecto, permiten obtener en este trabajo curvas de saturacion para los aisladores bajo estudio. Estas curvas, esencialmente dan los niveles maximos de contaminacion asi como la rapidez de acumulacion de

  17. Elements of a thermic method of preparing beta-sources with fused carriers, including strontium-90; Elements d'une methode thermique de preparation de sources beta avec des entraineurs fondus, y compris le strontium-90; Osnovy termicheskogo metoda prigotovleniya beta-istochnikov s plavlennymi nositelyami, vklyuchayushchimi strontsij-90; Bases de un metodo termico de preparacion de fuentes beta con portadores fundidos, incluido el estroncio-90

    Energy Technology Data Exchange (ETDEWEB)

    Bogdanov, N I; Zakharova, K P; Zimakov, P V; Kulichenko, V V

    1962-01-15

    comprises entre 100 et 1000{sup o}C, et expliquent le choix des parametres de base du procede employe. Ils precisent les fondements de la methode qui consiste a monter une preparation vitreuse contenant la quantite necessaire de {sup 90}Sr, sur des supports de forme et dimensions diverses en acier, ceramique et autres matieres. Enfin, les auteurs examinent les parametres de base qui permettent l'exploitation sure et sans danger des differents types de sources, et ils donnent des renseignements sur les sources de {sup 90}Sr preparees par la methode thermique. (author) [Spanish] Las fuentes de radiaciones ionizantes basadas en el radioisotopo {sup 90}Sr se utilizan ampliamente en la industria para los dispositivos y sistemas de control y regulacion automaticos. La preparacion de las fuentes consiste en la deshidratacion de una mezcla formada por una solucion radiactiva de nitrato de estroncio, y compuestos tales como el anhidrido borico, silice, alumina, etc. Por calentamiento de la mezcla deshidratada a temperaturas elevadas, se obtiene una masa fundida muy fluida que, una vez fria, da una masa vitrea que contiene la cantidad requerida de {sup 90}Sr. Los autores presentan datos y examinan los resultados obtenidos al estudiar la deshidratacion del sistema SrO - B{sub 2}O{sub 3}- SiO{sub 2} a temperaturas comprendidas entre 100 y 1000{sup o} C; tambien explican su eleccion de los parametros basicos del proceso tecnologico. Exponen en lineas generales un metodo que consiste en montar sobre acero, materiales ceramicos u otras sustancias, de distintas formas y dimensiones, una masa vitrea que contenga la cantidad requerida de {sup 90}Sr. La memoria estudia los parametros fundamentales para lograr una explotacion regular y segura de los distintos tipos de fuente, y presenta datos relativos y fuentes de {sup 90}Sr preparadas por el metodo termico. (author) [Russian] Istochniki ioniziruyushchikh izluchenij na osnove radioizotopa Sr''9''0 shiroko primenyayutsya v priborakh i skhemakh

  18. Assessing the potential toxicity of marine sediments found in petroleum industry areas: A new approach based on responses of postlarval shrimp; Evaluacion del potencial de toxicidad de sedimentos marinos en areas de la industria petrolera: Un nuevo metodo basado en respuestas de postlarvas de camarones

    Energy Technology Data Exchange (ETDEWEB)

    Evangelista, A.J.A.; Nascimento, I.A.; Pereira, S.A.; Lopes, M.B.N.L.; Martins, L.K.P. [Laboratorio de Bio Marinha e Biomonitoramento IBIO-UFBA, Campus Universitario de Ondina, Salvador (Brazil); Fillmann, G [Plymouth Marine Laboratory, West Hoe, PL (United Kingdom)

    2005-03-15

    impacted and relatively unperturbed environments, but also to separate the different degrees of impact among areas subjected to petroleum industry activities in the coastal environment. [Spanish] Se evaluo la toxicidad de sedimentos del area del noreste de la Bahia de Todos os Santos, Bahia, Brasil, para evaluar el impacto ambiental inducido por 50 anos de actividad industrial petrolera (Petrobras). Se recolectaron muestras de sedimento durante un ano, con intervalos de tres meses, en cuatro sitios relacionados con areas de extraccion (Ilha das Fontes, estacion 4), transporte (Ilhas de Madre de Deus y Pati, estaciones 2 y 3) y refinacion del petroleo (RELAM, estacion 1). Dos estaciones de referencia (5 y 6) se localizaron fuera del area de influencia del petroleo, al sur de la bahia. Se llevaron a cabo bioensayos estaticos por 96 h, usando postlarvas (PL) de Lytopenaeus vannamei con 7 a 8 dias de desarrollo. El ensayo fue realizado en contenedores con 200 g de sedimento superficial (1 cm de profundidad) y 2 L de agua (agua de mar filtrada, 28 ppm de salinidad, 27 {+-} C y DO bajo saturacion). Se alimentaron 15 PL en los contenedores diariamente con 60 nauplios de Artemia salina. Se monitorearon parametros quimicos. La mortalidad y la ganancia en peso seco fueron tomadas como parametros de validacion (end point). Los datos de mortalidad obtenidos de los sedimentos de las estaciones de Petrobras no mostraron diferencias significativas, en comparacion con las estaciones de referencia; sin embargo, la ganancia en peso seco mostro diferencias significativas entre estaciones. El valor maximo se alcanzo en la estacion 1 (refineria RELAM). Las estaciones 2 y 3 de las areas de transporte de petroleo no mostraron diferencias significativas. Para evaluar la sensibilidad de la prueba del sedimento para detectar contaminacion por la industria petrolera, los datos de toxicidad fueron considerados en terminos de niveles de hidrocarburos analizados en dichos sedimentos en las areas de

  19. Processes of heat transference during the construction of oil wells: inverse problem; Procesos de transferencia de calor durante la construccion de pozos petroleros: problema inverso

    Energy Technology Data Exchange (ETDEWEB)

    Olea Gonzalez, Ulises

    2007-08-15

    para modelar la estabilizacion termica de un pozo petrolero despues de que el fluido de perforacion se ha detenido, suponiendo que la formacion consiste en un medio poroso homogeneo. En el contexto matematico se trata de encontrar las condiciones iniciales del conjunto de ecuaciones diferenciales parciales que gobiernan los fenomenos de transferencia de calor en el pozo y yacimiento. Dichas ecuaciones forman un modelo bidimensional en estado transitorio. El modelo matematico se establece para cuatro regiones en el sistema pozo-formacion y las condiciones de frontera e inicial vinculan a las ecuaciones diferenciales parciales tanto para el pozo como para la formacion. Con lo anterior se obtiene una metodologia generada para determinar el campo de temperaturas de formacion. Posteriormente, se propone un analisis particular en funcion de las propiedades termofisicas de la geometria del pozo, de las condiciones de frontera y de la condicion inicial, parametro que es precisamente la incognita del problema. De conocer con anticipacion la solucion analitica del problema, suponiendo que todas las variables del problema (directo) son conocidas, es posible predecir, mediante metodos inversos, a la condicion inicial de la formacion supuesta en el problema directo. Para lo cual se exploran tres metodos inversos, el Metodo de Levenberg Marquardt (MLM), un Metodo de Control Proporcional Integral (PI) y uno referido a Inteligencia Artificial (IA). Para proponer la solucion, cada uno de los metodos utiliza en su funcion objetivo los registros a pozo cerrado y a profundidad constante, que serviran para efectuar el ajuste de la temperatura de formacion. La estructura del algoritmo MLM, ademas de estimar la condicion inicial de formacion, permitio explorar los eigenvalores y eigenvectores de la matriz Jacobiana, con lo que se identifico la variacion de los parametros de sensibilidad durante el proceso de convergencia en la estimacion de la temperatura de formacion; se determino que la

  20. Strain Dependence of the Frequencies and the Thermal Expansion of the Hexagonal Close-Packed Lattice; Variations, en Fonction de la Deformation, des Frequences et de la Dilatation Thermique du Reseau a Structure Hexagonale Compacte; Zavisimost' chastot i teplovogo rasshireniya geksagonal'noj reshetki s plotnoj upakovkoj ot napryazheniya; Variacion de las Frecuencias y de la Dilatacion Termica de la Red Hexagonal Compacta en Funcion de la Deformacion

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, R.; Ramji Rao, R. [Physics Department, Indian Institute of Technology, Madras (India)

    1965-04-15

    que la grandeur de cette difference soit independante des valeurs de m et n. En tenant compte d'une interaction avec des voisins plus eloignes, on peut s'attendre a une reduction de cette difference. Les auteurs comparent ces resultats theoriques aux resultats experimentaux obtenus avec le magnesium. (author) [Spanish] Recientemente se ha medido la dilatacion termica anisotropa de algunos metales de estructura hexagonal. Para desarrollar la teoria de la dilatacion termica anisotropa de las redes hexagonales compactas, es necesario estudiar la influencia de las deformaciones sobre las frecuencias de esas redes. Los autores han elegido una red hexagonal compacta con interaccion central de los atomos mas proximos de la forma Empty-Set = -a/{gamma}{sup m} + b/{gamma}{sup n} . Las deformaciones aplicadas son: 1) una dilatacion {zeta} a lo largo del eje z, y 2) una dilatacion uniforme bidimensional #Greek Lunate Epsilon Symbol#' a lo largo del plano basal. Estas deformaciones son las que intervienen en la teoria de la dilatacion termica, y ofrecen la ventaja de que no entranan desplazamientos interreticulares. Los autores determinan los parametros de Grueneisen {gamma}'{sub i} = - Partial-Differential log{omega}{sub i}/ Partial-Differential #Greek Lunate Epsilon Symbol#' y {gamma}'{sub i}' = - Partial-Differential log{omega}{sub i}/ Partial-Differential {zeta} para vectores de onda que siguen determinadas direcciones de simetria, comprobando que para las ramas acusticas estos parametros cambian considerablemente con la direccion y ofrecen un amplio margen de variacion. Una de las ramas acusticas transversales del plano basal tiene un valor negativo de {gamma}'' sean cuales fueren los valores de m y n. Se ha establecido la relacion de dependencia existente entre los momentos {mu}{sub 2}, {mu}{sub 4} y {mu}{sub 6} las deformaciones antes mencionadas. Se han determinado los limites superiores e inferiores de temperatura de los parametros de Grueneisen equivalentes {gamma}' y

  1. Influence of soil management practices and substrate availability on microbial biomass and its activities in some haplic luvisols

    Energy Technology Data Exchange (ETDEWEB)

    Friedel, Jurgen K [University Hohenheeim, Stuttgart (Germany)

    1996-07-01

    barbecho y con los sistemas de monocultivo. La razon principal de estas diferencias es un abastecimiento mas grande con residuos de cosecha y raices en los sistemas de rotacion de cultivos, que conduce a un mayor sustrato disponible para microorganismos. Los objetivos del estudio presente fueron describir los indices del sustrato disponible para microorganismos en suelos ara bles, dependiendo de las practicas de manejo de suelos, y relacionarlos con la biomasa y la actividad microbianas. En dos localidades (Muttergarten e Ihinger Hof, cerca de la Universidad de Hohenheim, Stuttgart, sudoeste de Alemania) fueron medidos los contenidos de trifosfato de adenosina y la actividad microbiana en Luvisoles haplicos. Como indices del sustrato disponible para microorganismos fueron determinados los compuestos organicos de carbon soluble en agua y se calculo la ateria organica de suelos jovenes susceptible a descomponerse en los fertilizantes organicos y en los residuos de cosecha y de raices, usando funciones de descomposicion empiricas. Los contenidos mas altos de ATP y las actividades microbianas mas altas fueron observados con la fertilizacion organica (abono liquido de ganado), antes que con la fertilizacion mineral. La labranza somera con un cultivador rotatorio condujo a valores mas altos de la propiedades microbianas en la parte superior del horizonte Ap que con la labranza con arado. Los parametros microbianos del suelo fueron mas altos en parcelas bajo una rotacion de cultivos de colza-cereales, en comparacion con una rotacion de cultivos de legumbres-cereales. La biomasa microbiana y sus actividades estuvieron relacionadas mas estrechamente a materia organica de suelos jovenes susceptible a descomponerse que al contenido de humus o a cualquiera otra propiedad del suelo. Los compuestos organicos de carbon soluble en agua no demostraron ser un indicador del sustrato disponible para microorganismos.

  2. Experimental comparison of standard fuel cells PEM in radial configuration, coil and spiral; Comparacion experimental de celdas de combustible tipo PEM en configuracion radial, serpentin y espiral

    Energy Technology Data Exchange (ETDEWEB)

    Cano Andrade, Sergio

    2008-12-15

    sustituir al petroleo surge la siguiente pregunta: cual de todas las fuentes posibles es la adecuada? Sin duda se debe tomar en cuenta otro factor importante en la eleccion de dicha fuente, el cual tiene que ver con el gran problema que la humanidad trata a diario: el efecto invernadero. Tomando en cuenta el efecto invernadero, las celdas de combustible en base a hidrogeno son la fuente de energia mas viable para sustituir al petroleo, ya que en su funcionamiento son amigables con el medio ambiente pues no producen contaminantes, reduciendo enormemente el problema del calentamiento global en que esta enfrascado el planeta. Es muy cierto que aun existen muchas desventajas en estas celdas de combustible en base a hidrogeno, pero las arduas investigaciones realizadas hasta la actualidad auguran un excelente futuro donde el plantea podra satisfacer su demanda energetica diaria en base a la tecnologia de hidrogeno. En trabajos futuros se debe tener especial cuidado en el control de la humedad de los gases antes de entrar a la celda de combustible, ya que es un parametro importante en el funcionamiento correcto de las celdas de combustible tipo PEM. En la presente investigacion se ilustra el avance en el estado del arte de la tecnologia de hidrogeno, especificamente con la generacion de electricidad en base a las novedosas configuraciones de celdas de combustible tipo PEM. Hasta el momento no se ha encontrado en bibliografia trabajo semejante donde se experimente con este tipo de configuracion radial para las tecnologias de hidrogeno. La geometria y los resultados presentados en este analisis corresponden a un trabajo de la mas alta categoria en el estado del arte de las celdas de combustible, ademas de que se tiene una amplia expectativa debido a los resultados altamente satisfactorios encontrados tanto numericamente como experimentalmente, en comparacion con otras geometrias.

  3. Optimization of a hydrocarbon bioremediation system at laboratory scale; Optimizacion de un sistema de biorremediacion de hidrocarburos a escala de laboratorio

    Energy Technology Data Exchange (ETDEWEB)

    Acuna, A. J.; Tonin, N. L.; Diaz, V.; Pucci, G. N.; Pucci, O. H. [Centro de Estudios e Investigacion en Microbiologia Aplicada (CEIMA), Universidad Nacional de la Patagonia San Juan Bosco (Argentina); ar, ntonin@unpata. edu.; com, victordj_2003@hotmail.; ar, granapu@unpata. edu.; ar, ceima@unpata. edu.

    2012-01-15

    The aim of this study was to optimize the parameters of moisture, temperature and ratio of nutrients to estimate the possibility of applying the technique of bioremediation in a soil contaminated with hydrocarbons. For this, an initial characterization of contaminated soil was made according to their physical and chemical characteristics and the number of heterotrophic and hydrocarbon degraders bacteria. Also the contaminant concentration by gravimetric method and by gas chromatography was studied. To optimize moisture and temperature, microcosms with moisture of 3%, 10%, 15% and 20% and temperatures of 5, 15, 28 and 37 degrees Celsius were used. The monitoring of the mineralization of hydrocarbons was performed by measuring the CO{sub 2} produced. To optimize the ratio of nutrients, different microcosms were designed and were monitored by oxygen consumption and by determination of hydrocarbons by gas chromatography. The C:N:P relationships studied were 100:20:2, 100:10:1, 100:5:0,5 and 100:1:0,1. The results indicate that the mineralization of hydrocarbons was optimal for moisture of 10% to 20% and temperatures of 25 degrees Celsius to 37 degrees Celsius with CO{sub 2} production values of 3000-4500 mg CO{sub 2} kg-1. The optimal C:N:P ratio was 100:1:0,1 in which the highest oxygen consumption was and the elimination of 83% of total hydrocarbons determined by gas chromatography with 78% and 89% of n-alkanes and polyaromatic hydrocarbons elimination, respectively. [Spanish] El objeto de este trabajo fue optimizar los parametros de humedad, temperatura y relacion de nutrientes para estimar la posibilidad de aplicar la tecnica de biorremediacion en un suelo contaminado con hidrocarburos. Para esto se realizo una caracterizacion inicial del suelo contaminado en funcion de sus caracteristicas fisicas y quimicas, su cantidad de microorganismos heterotrofos y degradadores de hidrocarburos. Tambien se estudio la concentracion del contaminante por metodo gravimetrico y

  4. Efectos de la variación de sobremedida debido al uso de 2 ½ ejes en la operación de acabado. // Effects of the over measure variation due to the use of 2 ½ axes in the finish operation.

    Directory of Open Access Journals (Sweden)

    R. Lemes Capla

    2008-01-01

    Full Text Available En el fresado de moldes y matrices usando una operación de 2 ½ ejes da como resultado una superficie con escalones, enforma de escalera, particularmente en el desbaste con una fresa de cabeza plana. El valor teorico del sobreespesor a cortaren el acabado es usualmente fijado por el CAM y no tiene en cuenta este exceso de material dejado en la operación dedesbaste. En general esa variacion significativa de la sobremedida es común y debe ser cortado en la operación de acabado.En el presente trabajo se aplican operaciones de corte con altas velocidades de corte (High Speed Cutting en una pieza quecontiene diferentes superficies y angulos de inclinacion 75, 45 y 7o. Inicialmente la pieza fue desbastada con una fresa decabeza plana de 12 mm de diámetro con bordes rectos afilados. Dos fresas de cabeza esfericas con 12 y 6 mm de diámetrofueron probadas con 75 y 45 mm de voladizo desde el soporte. La operación de acabado se realizo fresando en direccionesascendente y descendente en las tres inclinaciones. Los valores de acabado superficial fueron comparados teniendo encuenta los dos valores de voladizo y manteniendo constante todos los demás parametros de fresado. Los peores valores deacabado ocurrieron con el voladizo mayor, independiente de la inclinación. Los valores de acabado fueron ligeramentesuperiores que los esperados para una operación de acabado, sin embargo, importantes comparaciones pueden realizarsecon los valores de los resultados. Tambien fue verificado que en algunos casos el corte descendente produce mejoracabado, comparado con el corte ascendente.Palabras claves: Acabado; sobreespesor; fresado ascendente y descendente; alta velocidad de corte; moldes ymatrices.____________________________________________________________________________Abstract.In the molds and die milling using an operation of 2 ½ axes gives a surface as a result with steps, in stairway form,particularly in the roughing operations with a plane end milling

  5. Thermal responses and its relation with the building outdoor conditions; Respuestas termicas y su relacion con la envolvente del edificio

    Energy Technology Data Exchange (ETDEWEB)

    Marincic, Irene [Universidad de Sonora, Hermosillo, Sonora (Mexico); Isalgue, Antoni [Universidad Politecnica de Cataluna, Barcelona (Spain)

    2000-07-01

    entran y salen de los mismos, identificando tanto los fenomenos termicos mas relevantes que intervienen, como los factores geometricos y propiedades fisicas que influyen modificando el balance termico de cada sistema. En el presente trabajo se analiza el comportamiento termico experimental en edificios, en relacion con el ambiente exterior. Mas especificamente, la respuesta termica en el interior del edificio a diferentes distancias de la envolvente del mismo, teniendo en cuenta las distintas situaciones de aislamiento termico. Basandonos en datos medidos de temperatura en viviendas de construccion urbana tradicional, se analizan los efectos sobre la respuesta termica dependiendo de la distancia del punto considerado a la envolvente, considerando el grado de aislamiento termico que los separa. Mediante el uso de una metodologia basada en la funcion de transferencia experimental del edificio, se evalua el comportamiento termico tanto en el espacio temporal como en el frecuencial. Con esta metodologia, es posible evidenciar fenomenos y obtener parametros termicos que caracterizan a los aspectos dinamicos de la respuesta termica. El objetivo principal es extraer informacion del analisis de edificios, con el fin de extrapolar las conclusiones del comportamiento para el diseno termico apropiado de otras construcciones similares. Del analisis de respuestas termicas en diferentes localizaciones espaciales, se concluye que la distancia desde el envolvente (asi como las propiedades de la misma) tiene gran influencia sobre los efectos de inercia termica, que modifican en forma importante la respuesta, con cierto paralelismo con el efecto piel en la penetracion de campos electromagneticos en conductores. La localizacion espacial implica una cierta masa termica involucrada en cada caso, y esta a su vez, controla la penetracion de la oscilacion termica exterior.

  6. Repeat biopsy in patients with initial diagnosis of PIN; La biopsia ripetuta nei pazienti con diagnosi iniziale di PIN

    Energy Technology Data Exchange (ETDEWEB)

    De Matteis, Massimo [Azienda Ospedaliera Policlinico S. Orsola-Malpighi, Bologna (Italy). UO Radiologia Albertoni; Poggi, Cristina; De Martino, Antonietta; Pavlica, Pietro [Azienda Ospedaliera Policlinico S. Orsola-Malpighi, Bologna (Italy). UO Radiologia Palagi, Dipartimento area radiologica; Corti, Barbara [Azienda Ospedaliera Policlinico S. Orsola-Malpighi, Bologna (Italy). UO Anatomia ed istologia patologica, Dipartimento oncologico ed ematologico; Barozzi, Libero [Azienda Ospedaliera Policlinico S. Orsola-Malpighi, Bologna (Italy). UO Radiologia d' urgenza, Dipartimento emergenze ed accettazione

    2005-09-15

    indirizzare i pazienti alla biopsia ripetuta. Materiale e metodi. Abbiamo valutato i risultati di 72 biopsie ripetute in pazienti con una diagnosi di PIN ad una prima agobiopsia prostatica ecoguidata. A tutti e stato effettuato un numero minimo di 6 prelievi. Tutti avevano un PSA>4 ng/ml. Risultati. Sono stati rilevati alla biopsia ripetuta 15 adenocarcinomi su 50 pazienti (30%) con diagnosi iniziale di PIN a basso grado e 10 carcinomi su 22 (45,4%) con PIN ad alto grado. Sono stati diagnosticati 7 carcinomi in 18 pazienti (39%) nei quali il PSA era diminuito durante l'intervallo di osservazione, in 16 su 46 (35%) nei quali il PSA in aumento e 2 su 8 casi (25%) con PSA stabile. Conclusioni. I risultati sembrano confermare che il PIN puo essere considerato un precursore dell'adenocarcinoma prostatico o un'alterazione istologica frequentemente associata ad esso. I pazienti con diagnosi iniziale di PIN a basso grado e soprattutto quelli con PIN ad alto grado dovrebbero sistematicamente essere sottoposti a biopsia ripetuta a breve distanza per l'elevata frequenza di diagnosi finale di carcinoma. Non esistono ancora indicazioni condivise sull'intervallo temporale tra le due biopsie. Le variazioni del PSA che si possono riscontrare durante il periodo di osservazione non rappresentano un parametro statisticamente significativo per proporre o meno al paziente la ripetizione della biopsia prostatica.

  7. Integration of a thermal stresses supervisory system and useful life of steam turbine rotors; Integracion de un sistema supervisorio de esfuerzos termicos y vida util de rotores de turbinas de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Carnero, Antonio; Serrano, Luis E. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Nebradt, G. Jesus; Leyva, M. Luis [Comision Federal de Electricidad, Mexico, D.F. (Mexico)

    2007-11-15

    lado, la mayor eficiencia de centrales de ciclo combinado con respecto a centrales convencionales se refleja en un mayor costo de produccion de la energia electrica, lo que ha obligado a que unidades convencionales de generacion disenadas para operar con carga base, ahora sean utilizadas como unidades de carga variable para satisfacer la demanda durante las horas de mayor demanda. Lo anterior, repercute en una mayor frecuencia de operaciones de paros y arranques en calientes de turbinas, por lo que el dano por fatiga se incrementara al cambiar su regimen de operacion. En Mexico existen turbinas que llevan 15 o 20 anos en operacion y que no cuenta con un supervisor de esfuerzos termicos, por lo que al cambiar su operacion de carga base a carga variable es imprescindible instalar un supervisor de esfuerzos termicos del rotor, con el fin de limitar o reducir los esfuerzos termicos y con ello reducir el dano por fatiga para extender asi su vida util esencial. El articulo trata sobre la integracion de un sistema supervisor de esfuerzos termicos, que a partir de los parametros de operacion de la turbina, se determina el gradiente de temperaturas en la zona de sellos de laberinto entre el paso de control y el primer paso de la seccion del alta presion del rotor, se calculan los esfuerzos termicos y mecanicos y la fatiga, determinando el consumo de vida util por cada ciclo de operacion (paro y arranque).

  8. Calculation of sensitivities in electrical systems with SIFLETCA devices; Calculo de sensibilidades en sistemas electricos con dispositivos SIFLETCA

    Energy Technology Data Exchange (ETDEWEB)

    Rubio Marroquin, Gabriel Omar

    2004-03-15

    de potencia (CUFP). Ademas, se desarrolla en esta tesis las ecuaciones utilizadas en el Jacobiano del metodo Newton-Raphson, para resolver flujos de potencia incluyendo los dispositivos SIFLETCA. Se muestra diferentes aplicaciones que se tienen al instalar un dispositivo, tales como prevencion de flujos en anillo, barrera electronica, incremento en la capacidad de transmision y especificacion del flujo de potencia en lineas de transmision. Por otra parte, se desarrolla en la tesis un analisis de sensibilidades de un sistema de potencia en estado estacionario. Tambien se proponen en la tesis los parametros de control para los cuales se calcula las sensibilidades. Asimismo, se utiliza un indice de desempeno para medir el grado de congestion de un sistema electrico. Al calcular las sensibilidades se utiliza los resultados obtenidos de los flujos de potencia. Se usa 4 redes electricas para encontrar donde se debe situar cada dispositivo SIFLETCA para reducir la congestion en el sistema. Tambien, se compara el metodo desarrollado en la tesis con un metodo de sensibilidades que emplea flujos de CD para validacion y mostrar las ventajas de usar el metodo Newton en flujos de potencia.

  9. Design of very high speed electric generators;Diseno de generadores electricos de muy alta velocidad de giro

    Energy Technology Data Exchange (ETDEWEB)

    Labollita, Santiago [Universidad Nacional de Cuyo, Instituto Balseiro, Centro Atomico Bariloche (Argentina)

    2008-07-01

    This work approaches the design process of an electric generator suitable for running efficiently at high speed, driven by a turbo shaft.The axial flux concept was used.For the mechanical design of the prototype, cooling capacity and mounting method were considered, looking for simplicity of the parts evolved. Neodymium-iron-boron permanent magnets were used as magnetic source.For the electrical design, a calculation tool was developed in order to predict the prototype electrical parameters and optimize its geometry.The goal was to obtain 1 kW of electric power at a speed of 100,000 rpm.The efficiency and electrical behaviour of the prototype were characterized at speeds between 2,000 rpm and 30,000 rpm and then the behaviour at the design condition was predicted by obtaining an equivalent electric circuit.The estimated load voltage was 237 V as well as an electrical efficiency of 95%.Eddy current effects were not recognized. Increase of the internal resistance and decree of inductance were observed while raising the electric frequency.Finally, an electronic system was developed in order to use the prototype as a c.c. motor. Global performance was measured according to different supply characteristic. An optimum supply voltage was found.A maximum efficiency of 63% was reached.;El presente trabajo aborda el proceso de diseno de un generador electrico apto para funcionar eficientemente a alta velocidad, impulsado por un turboeje portatil. Se utilizo el concepto de flujo axial.En el diseno mecanico del prototipo se considero la capacidad de refrigeracion y la forma de montaje particular del conjunto, buscando la simplicidad de sus partes.Se utilizaron imanes permanentes de Neodimio-Hierro-Boro como fuente magnetica. Para el diseno electrico se genero una herramienta de calculo que permitio estimar los parametros electricos del prototipo y optimizar su geometria. Se busco obtener 1kW de potencia electrica a una velocidad de 100.000rpm.Se caracterizo el rendimiento y el

  10. Characterization of Hospital Residuals; Caracterizacion de Residuos Hospitalarios

    Energy Technology Data Exchange (ETDEWEB)

    Blanco Meza, A; Bonilla Jimenez, S

    1997-07-01

    , para asi poder determinar el horario de recoleccion de los desechos. En la segunda etapa se hizo un trabajo de campo que consistio en el levantamiento de la informacion cuantitativa y cualitativa del estado general del manejo de residuos. En la tercera y ultima etapa se organizo la informacion obtenida anteriormente para expresar los resultados como la tasa de produccion por dia por cama, generacion de residuos solidos por servicios muestreados, tipo de residuos solidos y densidad de los mismos. Con los resultados obtenidos se establecen criterios para determinar parametros de diseno para disposicion final ya sea por incineracion, trituracion, relleno sanitario o reciclaje de algunos materiales y politicas de almacenamiento de los residuos solidos que permitan determinar la frecuencia de recoleccion. Del estudio se concluye que es necesario mejorar las condiciones de manejo de los residuos en algunos aspectos, proveer al personal de aseo del equipo de recoleccion disposicion y de seguridad minimo para realizar este trabajo en forma eficiente y mantener un control de todos aquellos desechos peligrosos, entre ellos punzocortantes o contaminados, para que de esta manera se garantice una reduccion apreciable en el impacto que se ejerce sobre el ambiente. (Author)

  11. Analysis and evaluation of the main factors that influence the growing of the electrical power consumption in the national electrical sector, period 2000-2005; Analisis y evaluacion de los principales factores que influyen en el crecimiento del consumo de energia electrica en el sector electrico nacional, periodo 2000-2005

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar Luna, Luis Miguel

    2008-06-15

    de potencia (CUFP). Ademas, se desarrolla en esta tesis las ecuaciones utilizadas en el Jacobiano del metodo Newton-Raphson, para resolver flujos de potencia incluyendo los dispositivos SIFLETCA. Se muestra diferentes aplicaciones que se tienen al instalar un dispositivo, tales como prevencion de flujos en anillo, barrera electronica, incremento en la capacidad de transmision y especificacion del flujo de potencia en lineas de transmision. Por otra parte, se desarrolla en la tesis un analisis de sensibilidades de un sistema de potencia en estado estacionario. Tambien se proponen en la tesis los parametros de control para los cuales se calcula las sensibilidades. Asimismo, se utiliza un indice de desempeno para medir el grado de congestion de un sistema electrico. Al calcular las sensibilidades se utiliza los resultados obtenidos de los flujos de potencia. Se usa 4 redes electricas para encontrar donde se debe situar cada dispositivo SIFLETCA para reducir la congestion en el sistema. Tambien, se compara el metodo desarrollado en la tesis con un metodo de sensibilidades que emplea flujos de CD para validacion y mostrar las ventajas de usar el metodo Newton en flujos de potencia.

  12. Internal heat exchange in an ejector-compression solar refrigeration system with R142b

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, Joge I; Estrada, Claudio A; Best, Roberto [Centro de Investigacion en Energia, UNAM, Temixco, Morelos (Mexico); Dorantes Ruben, J [Departamento de Energia, UNAM Azcapotzalco, Mexico, D.F. (Mexico)

    2000-07-01

    parametricas tales como la eficiencia del eyector, la temperatura de generacion con diferentes eficiencias de sobrecalentamiento, temperatura de condensacion e intercambiadores de calor. Como se sabe, los parametros mas importantes en el analisis de sistemas de eyector-compresion son la proporcion de arrastre U y las eficiencias del sistema COP y {epsilon}. El COP y {epsilon} asi como la proporcion y arrastre U corresponden a la mas alta efectividad de los intercambiadores, las mas altas temperaturas de sobrecalentamiento del generador y las mas altas eficiencias del eyector y las mas bajas temperaturas del condensador. Para las relaciones COP y {epsilon} la maxima corresponde a las mismas variables independientes previamente mencionadas para una de las temperaturas de sobrecalentamiento del generador mas altas. En este caso el resultado indica que la eficiencia en exergia {epsilon} no contradice la informacion dada por la eficiencia de energia COP. De esta manera para seleccionar correctamente y para la condicion de diseno optimo es suficiente emplear la relacion COP cuyo maximo valor para los datos mostrados corresponde a una temperatura de sobrecalentamiento del generador de alrededor de 110 grados Celsius que puede ser alcanzada solamente por colectores tubulares evacuados o por concentradores solares CPC.

  13. Improved organic scintillation detectors; Possibilites de perfectionnement des detecteurs organiques a scintillations; Usovershenstvovannye organicheskie stsintillyatsionnye detektory; Detectores organicos de centelleo perfeccionados

    Energy Technology Data Exchange (ETDEWEB)

    Birks, J B [University of Manchester, Manchester (United Kingdom)

    1962-04-15

    Equations have been derived for the practical scintillation efficiency (photo-electrons/MeV) of organic crystals and solutions in terms of molecular parameters and these have been applied to the more important scintillator systems, for photomultipliers with S11 (glass window) and S13 (quartz window) responses. The results suggest several improvements in current organic scintillation detector practice: the use of binary rather than ternary solutions; the use of quartz rather than glass windows; and the reconsideration of mixed crystal scintillators based on naphthalene. Improvements by factors of 2 or more in the figure of merit (practical efficiency/decay time) for fast-scintillation counting can be obtained. (author) [French] L'auteur a etabli des equations pour determiner le rendement de scintillation (photoelectrons/MeV) de