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Sample records for na biomasa vo

  1. AC conductivity and dielectric behavior of polyaniline/sodium metavenadate (PANI/NaVO3) composites

    International Nuclear Information System (INIS)

    The conducting polyaniline/sodium metavenadate (PANI/NaVO3) composites were synthesized by single step in situ polymerization technique by placing finely grinded powder of NaVO3 during the polymerization of aniline. The formation of mixed phases of the polymer together with the conducting emeraldine salt phase was confirmed by spectroscopic techniques like FTIR. SEM images indicated a systematic morphological variation of particles aggregated in the composite matrix as compared to the pristine PANI. AC conductivity and dielectric behavior of these composites were investigated in the frequency range 50 Hz to 5 MHz. It is found that AC conductivity obeyed the power law index and the variation of conductivity with wt% of NaVO3 could be related to conductivity relaxation phenomenon. These composites have shown high dielectric constant, which is related to polarization. It is seen that both dielectric constant and dielectric loss decrease with increase in frequency. Variations in measured parameters of AC response with increasing frequency of these composites are found to follow systematic trends that are similar to those observed with temperature and doping.

  2. Successive orbital ordering transitions in NaVO_2

    Energy Technology Data Exchange (ETDEWEB)

    Klimczuk, Tomasz W [Los Alamos National Laboratory; Mcqueen, T [PRINCETON U.; Stephens, P W [STONY BROOK U.; Huang, Q [NIST CENTER FOR NEUTRON; Ronning, Filip [Los Alamos National Laboratory; Cava, R [PRINCETON U.

    2008-01-01

    Temperature-dependent dc susceptibility, heat capacity, and x-ray and neutron diffraction measurements on powder samples of the layered triangular-lattice material NaY02 reveal two successive phase transitions. At high temperature the structure is rhomobohedral, with all six inplane V-V distances equivalent. At T = 98K, the system undergoes a second order phase transition to a monoclinic intermediate temperature phase in which the in-plane Y -Y distances separate into four short and two long bonds, corresponding to orbital ordering of one electron per y3+. Below T 93K, there is a first order phase transition to a low temperature monoclinic phase, in which there are four long and two short in-plane Y -Y distances, consistent with orbital ordering of two electrons per y 3+ on a triangular lattice. Long range magnetic ordering of 0.98(2),uB per y 3 + (3d2) sets in at the T 93K structural transition. The low temperature structure ofNa Y02 displays orbital ordering that, although predicted by first principle calculations, has not previously been observed in this class of materials.

  3. Crystal structure and spectroscopic properties of Na2K6(VO)(2)(SO4)7

    DEFF Research Database (Denmark)

    Karydis, D.A.; Boghosian, S.; Nielsen, Kurt; Eriksen, Kim Michael; Fehrmann, Rasmus

    2002-01-01

    Red-brown crystals of a new mixed alkali oxo sulfato vanadium(V) compound Na2K6(VO)(2)(SO4)(7), suitable for X-ray determination, have been obtained from the catalytically important binary molten salt system M2S2O7-V2O5 (M = 80% K and 20% Na). By slow cooling of a mixture with the mole fraction X-V2O5 = 0.24 from 325 degreesC, i.e., just below the liquidus temperature, to the solidus temperature of around 300 degreesC, a dark reddish amorphous phase was obtained containing crystals of the earlie...

  4. High-temperature Raman spectroscopic study of vanadoborate Na3VO2B6O11

    Science.gov (United States)

    Ji, Zhang; De-Ming, Zhang; Qing-Li, Zhang; Shao-Tang, Yin

    2016-03-01

    Raman spectra of a vanadoborate (Na3VO2B6O11) crystal from room temperature up to the melting point have been recorded. The main internal vibrational modes of the crystal have been assigned. It was found that all the Raman bands exhibit decreases in frequency and the widths of the Raman bands increase with the increase of temperature. However, no phase transition was observed under 525 °C. The micro-structure of its melt was studied by quantum chemistry ab initio calculation. The continuous three-dimensional network of the crystal collapsed and transformed into VO4 and VBO6 clusters during the melting process with an isomerization reaction from four-coordinated boron to a three-coordinated species. Project supported by the National Natural Science Foundation of China (Grant Nos. 51302268 and 51102239) and the Natural Science Foundation of Anhui Province, China (Grant No. KJ2015A339).

  5. Neutron and X-ray diffraction studies on the high temperature phase of Mn{sub 3}(VO{sub 4}){sub 2}, the new isostructural compound NaMn{sub 4}(VO{sub 4}){sub 3} and their mixed crystals Na{sub x}Mn{sub 4.5-x/2}(VO{sub 4}){sub 3} (0{<=}x{<=}1)

    Energy Technology Data Exchange (ETDEWEB)

    Clemens, Oliver [Universitaet des Saarlandes, Institut fuer Anorganische und Analytische Chemie und Radiochemie, Am Markt, Zeile 5, 66125 Saarbruecken (Germany); Haberkorn, Robert [Universitaet des Saarlandes, Anorganische Festkoerperchemie, Am Markt, Zeile 3, 66125 Saarbruecken (Germany); Springborg, Michael [Universitaet des Saarlandes, Physikalische und Theoretische Chemie, Campus B2 2, 66123 Saarbruecken (Germany); Beck, Horst Philipp, E-mail: hp.beck@mx.uni-saarland.de [Universitaet des Saarlandes, Institut fuer Anorganische und Analytische Chemie und Radiochemie, Am Markt, Zeile 5, 66125 Saarbruecken (Germany)

    2012-10-15

    This paper presents a detailed structure analysis (combined Rietveld analysis of X-ray and neutron powder diffraction data as well as quantum mechanical calculations) of the high temperature phase of Mn{sub 3}(VO{sub 4}){sub 2} (space group I4 Macron 2d). Special attention is directed to the analysis of the local coordination around Mn{sup 2+} ions or vacancies within a stella quadrangula configuration of anions. Furthermore, the new compound NaMn{sub 4}(VO{sub 4}){sub 3} is described as well as a range of mixed crystals between NaMn{sub 4}(VO{sub 4}){sub 3} and Mn{sub 3}(VO{sub 4}){sub 2} (described by the formula Na{sub x}Mn{sub 4.5-x/2}(VO{sub 4}){sub 3}, 0{<=}x{<=}1) which were synthesized by a solid state route. All compounds were shown to be isostructural to the high temperature phase Mn{sub 3}(VO{sub 4}){sub 2}. - Graphical abstract: The crystal structure of the new compound NaMn{sub 4}(VO{sub 4}){sub 3}. Highlights: Black-Right-Pointing-Pointer We present neutron and X-ray diffraction studies on high temperature-Mn{sub 3}(VO{sub 4}){sub 2}. Black-Right-Pointing-Pointer Structural details of partly filled stellae quadrangulae positions are discussed. Black-Right-Pointing-Pointer Refined structural parameters and theoretical calculations are compared. Black-Right-Pointing-Pointer We investigate the mixed crystal system Mn{sub 3}(VO{sub 4}){sub 2}-NaMn{sub 4}(VO{sub 4}){sub 3}.

  6. Pressure-induced amorphization of NaVO/sub 3 at room temperature and its re-crystallization

    International Nuclear Information System (INIS)

    Pressure-induced amorphization is the subject of intense study for the past few years because of its importance in material science and in solid state physics. We reported a crystalline-amorphous phase transition at ca 60kbar in NaVO1/3, which is the lowest pressure for such transitions in ionic crystals. The transition is marked by the sudden appearance of very broad bands at the 800 and 350 cm/sup -1 regions. The amorphization includes the complete breaking up of the infinite chains of corner-linked tetrahedral VO/sub 4, most likely into VO/sup -/sub 3. On decompression, the amorphous phase transforms to another phase, probably also amorphous at ca 40 kbar. It reverts to the stable ambient condition ?-phase upon heating. Here we report on the details of the transtitional region and the re-linking of the VO/sub 4 chains upon heating. (authors)

  7. Neutron and X-ray diffraction studies on the high temperature phase of Mn3(VO4)2, the new isostructural compound NaMn4(VO4)3 and their mixed crystals NaxMn4.5?x/2(VO4)3 (0?x?1)

    International Nuclear Information System (INIS)

    This paper presents a detailed structure analysis (combined Rietveld analysis of X-ray and neutron powder diffraction data as well as quantum mechanical calculations) of the high temperature phase of Mn3(VO4)2 (space group I42d). Special attention is directed to the analysis of the local coordination around Mn2+ ions or vacancies within a stella quadrangula configuration of anions. Furthermore, the new compound NaMn4(VO4)3 is described as well as a range of mixed crystals between NaMn4(VO4)3 and Mn3(VO4)2 (described by the formula NaxMn4.5-x/2(VO4)3, 0?x?1) which were synthesized by a solid state route. All compounds were shown to be isostructural to the high temperature phase Mn3(VO4)2. - Graphical abstract: The crystal structure of the new compound NaMn4(VO4)3. Highlights: ? We present neutron and X-ray diffraction studies on high temperature-Mn3(VO4)2. ? Structural details of partly filled stellae quadrangulae positions are discussed. ? Refined structural parameters and theoretical calculations are compared. ? We investigate the mixed crystal system Mn3(VO4)2NaMn4(VO4)3.

  8. Cintica do VO2 durante o exerccio realizado na potncia crtica em ciclistas e indivduos no-treinados no ciclismo / VO2 Kinetics during exercise performed at critical power in cyclists and untrained individuals

    Scientific Electronic Library Online (English)

    Renato Aparecido Corra, Carit; Camila Coelho, Greco; Dalton Mller, Pessa Filho.

    2013-06-01

    Full Text Available O objetivo foi analisar a cintica do consumo de oxignio (VO2) na potncia crtica (PC), em indivduos com diferentes nveis de aptido aerbia no ciclismo. Seis ciclistas treinados (GT) e sete indivduos no-treinados (GNT) realizaram os seguintes protocolos em cicloergmetro: (a) progressivo at [...] a exausto para determinao do VO2max e sua respectiva intensidade (IVO2max); (b) trs testes em cargas constantes at a exausto a 95-110%IVO2max para determinao da PC; e (c) um teste em carga constante at a exausto a 100%PC. No exerccio a 100%PC, o componente lento expresso em valor absoluto (GT: 342,4165,8 ml.min-1 vs. GNT: 571,3170,1 ml.min-1) e relativo ao aumento do VO2 em exerccio (GT: 10,04,6% vs. GNT: 26,67,3%) foram menores para GT. O VO2 ao final do exerccio (GT: 89,88,4%VO2max vs. GNT: 97,42,8%VO2max) foi significativamente menor no grupo GT (? = 0,045), sendo similar ao VO2max no grupo GNT. Portanto, o nvel de aptido aerbia pode influenciar as respostas do VO2 ao exerccio em PC. Abstract in english The objective was to analyze the oxygen uptake (VO2) kinetics during exercise performed at critical power (CP) in subjects with different aerobic status in cycling. Six trained cyclists (GT) and seven non-trained subjects (GNT) underwent to the following protocols in cyclergometer: (a) incremental t [...] o exhaustion to determine VO2max and its respective workload (IVO2max); b) three square-wave tests to exhaustion at 95-110% IVO2max to determine CP, and; (c) one square-wave test to exhaustion at 100%CP. During the exercise at CP the slow component expressed as absolute value (GT: 342.4165.8 ml.min-1 vs. GNT: 571.3170.1 ml.min-1) and as the relative contribution to the increase of VO2 during exercise (GT: 10.04.6% vs. GNT: 26.67.3%) were lower for trained subjects. The VO2 at the end of the exercise at PC (GT: 89.88.4%VO2max vs. GNT: 97.42.8%VO2max) was significantly lower in GT (? = 0.045), and similar to VO2max in GNT. Therefore, the aerobic level might influence the VO2 responses to exercise at PC.

  9. Relao entre modificaes cinemticas da corrida e o tempo limite na vVO2mx / Relationship between running kinematic changes and time limit at vVO2max

    Scientific Electronic Library Online (English)

    Leonardo, De Lucca; Sebastio Iberes Lopes, Melo.

    Full Text Available A corrida realizada na velocidade do consumo mximo de oxignio (vVO2mx) pode ocasionar modificaes nos parmetros cinemticos e assim, aumentar o custo energtico ao longo do tempo. O objetivo do presente estudo foi analisar caractersticas cinemticas da articulao do tornozelo e joelho durante [...] a corrida na vVO2mx e a relao entre modificaes cinemticas e o tempo limite na vVO2mx(Tlim). Onze voluntrios ativos fisicamente foram submetidos a um teste incremental de corrida para determinar a vVO2mx e posteriormente, a um teste de velocidade constante na vVO2mx. As variveis cinemticas foram adquiridas atravs de filmagem bidimensional a 210Hz no plano sagital esquerdo, no estgio inicial e final da corrida. De todas as variveis angulares analisadas, a mxima plantiflexo no balano (p Abstract in english Exhaustive running at maximal oxygen uptake velocity (vVO2max) can alter running kinematic parameters and increase energy cost along the time. The aims of the present study were to compare characteristics of ankle and knee kinematics during running at vVO2max and to verify the relationship between c [...] hanges in kinematic variables and time limit (Tlim). Eleven male volunteers, recreational players of team sports, performed an incremental running test until volitional exhaustion to determine vVO2max and a constant velocity test at vVO2max. Subjects were filmed continuously from the left sagittal plane at 210 Hz for further kinematic analysis. The maximal plantar flexion during swing (p

  10. Efeitos do estado e especificidade do treinamento aerbio na relao %VO2max versus %FCmax durante o ciclismo Effects of the state and specificity of aerobic training on the %VO2max versus %HRmax ratio during cycling

    OpenAIRE

    Fabrizio Caputo; Camila Coelho Greco; Benedito Srgio Denadai

    2005-01-01

    OBJETIVO: Determinar os efeitos do estado e especificidade de treinamento aerbio na relao entre o percentual do consumo mximo de oxignio (%VO2max) e o percentual da frequncia cardaca mxima (%FCmax) durante o exerccio incremental realizado no cicloergmetro. MTODOS: Sete corredores, 9 ciclistas, 11 triatletas e 12 sedentrios, todos do sexo masculino e aparentemente saudveis, foram submetidos a um teste incremental at a exausto no cicloergmetro. Regresses lineares entre %VO2max ...

  11. Hot corrosion behaviour of Fe-Al based intermetallic in molten NaVO3 salt

    International Nuclear Information System (INIS)

    The hot corrosion of sprayed Fe-40 (at.%)Al intermetallic alloy with additions of boron and alumina whiskers in molten NaVO3 at 700 deg. C has been evaluated by potentiodynamic polarization curves and electrochemical impedance spectroscopy, EIS, techniques. For short exposure times, the corrosion mechanism under these conditions was observed to be controlled by an activation process, whereas for longer exposure times, the corrosion process was under diffusion control due to the growing of an Al2O3 oxide scale, which made the diffusion of both reducing and oxidizing species through the scale to the alloy or scale surfaces more difficult. Equivalent electric model used to simulate the EIS data showed that a finite length Warburg diffusion could properly characterize the diffusion process, which confirmed the formation of a compact corrosion product scales containing rich aluminium oxide. Thus, the corrosion process was under diffusion control of aggressive ions through the formed scale. The electrochemical study was complemented by scanning electronic microscopy characterization and micro chemical analysis.

  12. Graphene quantum dots coated VO2 arrays for highly durable electrodes for Li and Na ion batteries.

    Science.gov (United States)

    Chao, Dongliang; Zhu, Changrong; Xia, Xinhui; Liu, Jilei; Zhang, Xiao; Wang, Jin; Liang, Pei; Lin, Jianyi; Zhang, Hua; Shen, Ze Xiang; Fan, Hong Jin

    2015-01-14

    Nanoscale surface engineering is playing important role in enhancing the performance of battery electrode. VO2 is one of high-capacity but less-stable materials and has been used mostly in the form of powders for Li-ion battery cathode with mediocre performance. In this work, we design a new type of binder-free cathode by bottom-up growth of biface VO2 arrays directly on a graphene network for both high-performance Li-ion and Na-ion battery cathodes. More importantly, graphene quantum dots (GQDs) are coated onto the VO2 surfaces as a highly efficient surface "sensitizer" and protection to further boost the electrochemical properties. The integrated electrodes deliver a Na storage capacity of 306 mAh/g at 100 mA/g, and a capacity of more than 110 mAh/g after 1500 cycles at 18 A/g. Our result on Na-ion battery may pave the way to next generation postlithium batteries. PMID:25531798

  13. Reprodutibilidade do VO2Mx estimado na corrida pela frequncia cardaca e consumo de oxignio de reserva / Reliability of VO2Max estimated in treadmill running by heart rate reserve and power output

    Scientific Electronic Library Online (English)

    Tony Meireles, Santos; Bruno Ferreira, Viana; Alberto Souza, S Filho.

    2012-03-01

    Full Text Available Objetivou-se comparar os efeitos de utilizao da frequncia cardaca mxima medida (FCpico) vs. predita (FC Predita) na estimativa do VO2Mx em esteira pelo mtodo de FC e VO2 de reserva. Dezoito homens (27,5 7,1 anos, 73,7 12,6 kg, 174,8 10,2 cm) realizaram na primeira visita um teste progre [...] ssivo mximo para determinar a FCpico. Nas duas visitas seguintes foram realizados os testes aerbios submximos em esteira com estgio de 6 min a 75% da FC de reserva. O VO2Mx foi estimado pelo uso conjunto das equaes de FC, VO2 de reserva e equao de corrida do ACSM. No foi observada diferena significativa (teste t) entre as estimativas de VO2Mx a partir da FCpredita e FCpico. O coeficiente de correlao intraclasse e erro tpico da medida utilizando FCpredita e FCpico foram 0,89, 2,43 mL.kg-1.min-1 (5%) e 0,83, 2,43 mL.kg-1.min-1 (4,9%), respectivamente. O uso da abordagem estimada para determinao da FC mxima mostrou-se adequado para a determinao do VO2Mx com um pequeno erro tpico da medida. Abstract in english The objective was to determine the reliability of the VO2Max estimate on a treadmill using the measured (HRpeak) vs. the predicted (HRpredicted) maximum heart rate (HR). Eighteen men (27.5 7.1 years, 73.7 12.6 kg, 174.8 10.2 cm) performed, in the first visit, a progressive test to determine the [...] HRpeak. In the two following visits, submaximal aerobic tests were performed on a treadmill with a 6 min at 75% HR reserve. VO2Max was estimated by means of the equations of HR, VO2 reserve and the ACSM running equation. The intraclass correlation coefficient and the typical error of measurement using HRPredicted and HRpeak were 0.89, 2.43 ml.kg-1.min-1 (5%) and 0.83, 2.43 mL.kg-1.min-1 (4.9%), respectively. There was no significant difference (t test) between the estimates of VO2Max from the HRpeak and HRpredicted. The use of the HRpredicted was considered appropriate for VO2Max estimation, with a small typical error of measurement.

  14. Efeitos do estado e especificidade do treinamento aerbio na relao %VO2max versus %FCmax durante o ciclismo Effects of the state and specificity of aerobic training on the %VO2max versus %HRmax ratio during cycling

    Directory of Open Access Journals (Sweden)

    Fabrizio Caputo

    2005-01-01

    Full Text Available OBJETIVO: Determinar os efeitos do estado e especificidade de treinamento aerbio na relao entre o percentual do consumo mximo de oxignio (%VO2max e o percentual da frequncia cardaca mxima (%FCmax durante o exerccio incremental realizado no cicloergmetro. MTODOS: Sete corredores, 9 ciclistas, 11 triatletas e 12 sedentrios, todos do sexo masculino e aparentemente saudveis, foram submetidos a um teste incremental at a exausto no cicloergmetro. Regresses lineares entre %VO2max e %FCmax foram determinadas para cada indivduo. Com base nessas regresses, foram calculados %FCmax correspondentes a determinados %VO2max (50, 60, 70, 80 e 90% de cada participante. RESULTADOS: No foram encontradas diferenas significantes entre todos os grupos nos %FCmax para cada um dos %VO2max avaliados. Analisando-se os voluntrios como um nico grupo, as mdias dos %FCmax correspondentes a 50, 60, 70, 80 e 90% %VO2max foram 67, 73, 80, 87, e 93%, respectivamente. CONCLUSO: Nos grupos analisados, a relao entre o %VO2max e %FCmax durante o exerccio incremental no ciclismo no dependente do estado e especificidade do treinamento aerbio.OBJECTIVE: To determine the effects of the status and specificity of exercise training in the ratio between maximum oxygen consumption (%VO2max and the percentage of maximal heart rate (%HRmax during incremental exercise on a cycle ergometer. METHODS: Seven runners, 9 cyclists, 11 triathletes, and 12 sedentary individuals, all male and apparently healthy, underwent exhaustive incremental exercise on cycle ergometers. Linear regressions between %VO2max x %HRmax were determined for each individual. Based on these regressions, %HRmax was assessed corresponding to a determined %VO2max (50, 60, 70, 80, and 90% from each participant. RESULTS: Significant differences were not found between the groups in %HRmax for each of the %VO2max assessed. Analyzing the volunteers as a single group, the average of the corresponding %HRmax to 50, 60, 70, 80, and 90% %VO2max were 67, 73, 80, 87, and 93%, respectively. CONCLUSION: The ratio between %VO2max and %HRmax in the groups assessed during incremental exercise on the bicycle is not dependent on the status and specificity of aerobic exercise training.

  15. Structural, luminescence, and electronic properties of the alkaline metal-strontium cyclotetravanadates M2Sr(VO3)4 (M=Na, K, Rb, Cs)

    International Nuclear Information System (INIS)

    Structural, luminescence, and electronic properties of the family of alkaline metal-strontium cyclotetravanadates M2Sr(VO3)4, M=Na, K, Rb, and Cs have been characterized by means of elemental analyses, x-ray powder diffraction, neutron diffraction, electron diffraction, infrared, Raman, photo, x rays, pulse cathode beam excitation, x-ray photoelectron spectroscopy and band structure calculations. The M2Sr(VO3)4 system have tetragonal structures Na-, K-, Rb-P4/nbm and Cs-P4/mmm, with a=10.63449(4), 10.94106(6), 11.08889(8), 7.9183(3) and c=4.96205(4), 5.31600(4), 5.46682(8), 5.5778(3) A, respectively. The main structural feature of M2Sr(VO3)4 is tetracyclic [V4O12] units. When going from Na2Sr(VO3)4 to Cs2Sr(VO3)4 do the coordination polyhedron around the alkaline metal change continuously from an octahedron to a hexagonal prism and that around the strontium from a square antiprism to a square prism. The hybridized O 2p-V 3d states of tetracyclic [V4O12] units have a dominant influence on the electronic structure of these compounds. All M2Sr(VO3)4 are semiconducting with a decreasing LDA band gap (Ea) from 2.02 for Na2Sr(VO3)4 to 1.56 eV for Cs2Sr(VO3)4

  16. Near-infrared downconversion through host sensitized energy transfer in Yb3+-doped Na2YMg2(VO4)3

    Science.gov (United States)

    Li, Yong; Wei, Xiantao; Chen, Hongmei; Pan, Yan; Ji, Yuexia

    2015-12-01

    Host sensitized near-infrared emitting phosphor Na2YMg2(VO4)3:Yb3+ was fabricated by a sol-gel method. Efficient broad emission is observed under ultraviolet excitation ranging from 240 nm to -400 nm and this luminescence originates from ligand-metal charge transfer of 2p of O2- to 3d of V5+. Under excitation of ultraviolet light in the broad absorption band, intense near-infrared emission of Yb3+ around 974 nm is observed for Yb3+-doped Na2YMg2(VO4)3. Through study of photoluminescence spectra, fluorescence decay curves and concentration-dependent luminescence, mechanism of energy transfer from VO4 group to Yb3+ was proposed to rationalize the downconversion process. This phosphor with performance of ultra-violet to near-infrared downconversion could have potential application in improving efficiency of silicon-based solar cell.

  17. Hot corrosion behaviour of Fe-Al based intermetallic in molten NaVO{sub 3} salt

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa-Medina, M.A. [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas Norte No. 152, Col. San Bartolo Atepehuacan, C.P. 07730 Mexico, D.F. (Mexico)], E-mail: maespin@imp.mx; Carbajal-De la Torre, G. [Facultad de Ingenieria Mecanica, UMSNH, Santiago Tapia 403 Col. Centro, C.P. 58098 Morelia, Michoacan (Mexico); Liu, H.B. [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas Norte No. 152, Col. San Bartolo Atepehuacan, C.P. 07730 Mexico, D.F. (Mexico); Martinez-Villafane, A. [CIMAV, Complejo Industrial Chihuahua, Chihuahua (Mexico); Gonzalez-Rodriguez, J.G. [CIMAV, Complejo Industrial Chihuahua, Chihuahua (Mexico); UAEM-CIICAP, Av. Universidad 1001, Col. Chamilpa, Cuernavaca, Morelos (Mexico)

    2009-06-15

    The hot corrosion of sprayed Fe-40 (at.%)Al intermetallic alloy with additions of boron and alumina whiskers in molten NaVO{sub 3} at 700 deg. C has been evaluated by potentiodynamic polarization curves and electrochemical impedance spectroscopy, EIS, techniques. For short exposure times, the corrosion mechanism under these conditions was observed to be controlled by an activation process, whereas for longer exposure times, the corrosion process was under diffusion control due to the growing of an Al{sub 2}O{sub 3} oxide scale, which made the diffusion of both reducing and oxidizing species through the scale to the alloy or scale surfaces more difficult. Equivalent electric model used to simulate the EIS data showed that a finite length Warburg diffusion could properly characterize the diffusion process, which confirmed the formation of a compact corrosion product scales containing rich aluminium oxide. Thus, the corrosion process was under diffusion control of aggressive ions through the formed scale. The electrochemical study was complemented by scanning electronic microscopy characterization and micro chemical analysis.

  18. Cintica do consumo de oxignio e tempo limite na vvo2max: comparao entre homens e mulheres Oxygen uptake kinetics and threshold time at the vVO2max: tomparison between men and women

    OpenAIRE

    Paulo Henrique Silva Marques Azevedo; Joo Carlos de Oliveira; Herbert Gustavo Simes; Vilmar Baldissera; Srgio Eduardo de Andrade Perez

    2010-01-01

    Foi investigada a influncia do gnero no tempo limite (Tlim) e na cintica do VO2 durante corrida na velocidade associada ao VO2max (vVO2max) em nove homens e nove mulheres, todos adultos, jovens e sedentrios, com idades entre 20 e 30 anos. Homens e mulheres realizaram dois testes em esteira rolante, sendo um teste incremental para determinar VO2max (42,66 4,50 vs. 32,92 6,03mL.kg-1.min-1) e vVO2max (13.2 1.5 vs. 10,3 2,0km.h-1), respectivamente. Um segundo teste com carga constante...

  19. Efeito do tempo de intervalo da amostra ventilatria na variabilidade do consumo mximo de oxignio (VO2 mx em jogadores de futebol profissional

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Santos Silva

    1999-04-01

    Full Text Available O propsito deste estudo foi verificar, em futebolistas profissionais, o impacto de sete intervalos de tempo sobre a varivel fisiolgica consumo mximo de oxignio (VO2 mx. Dezoito jogadores de futebol com mdia de idade de 24 4 anos (18-31, peso de 72,5 5,9kg (62-83 e estatura de 176,5 7,0cm (164-188 foram submetidos a teste ergomtrico mximo em esteira rolante, utilizando-se protocolo escalonado contnuo. A resposta de freqncia cardaca (FC foi registrada por meio de um eletrocardigrafo computadorizado de 12 derivaes simultneas. A ventilao pulmonar (V E, o consumo de oxignio (VO2, a produo de dixido de carbono (VCO2 e a razo de troca respiratria (RER foram calculadas a partir de valores medidos por um sistema espiromtrico computadorizado. Os resultados deste estudo demonstraram que houve variabilidade significante do VO2 mx (p < 0,05 somente quando se comparou a resposta instantnea respirao-a-respirao (breath-by-breath em relao aos outros intervalos de tempos analisados (10, 20, 30, 40, 50 e 60 segundos, respectivamente. Concluindo, durante o exerccio de intensidade progressiva, observou-se que o aumento do VO2 foi proporcional diminuio do intervalo de tempo da coleta ventilatria. O tempo de intervalo maior subestimou esse aumento. Assim, sugere-se que o avaliador utilize intervalos mdios na faixa de tempo entre 10 e 60 segundos, pois no foi verificada diferena estatstica significante entre esses intervalos.

  20. Incluso do equivalente do lactato sanguneo O2 na regresso de intensidade de exerccio VO2 aumenta o gasto energtico de corrida e diminui sua preciso

    Directory of Open Access Journals (Sweden)

    Victor Machado Reis

    2013-12-01

    Full Text Available INTRODUO E OBJETIVOS: Investigar se a incluso do equivalente energtico de lactato sanguneo (LS em intensidades submximas alteraria o gasto energtico de corrida (Gc estimado para corrida supramxima de alta intensidade assim como sua preciso MTODOS: O Gc foi determinado a partir da curva de regresso de velocidade do VO2. Para cada sujeito, uma regresso alternativa foi estabelecida em que energia equivalente a 3 ml de O2 kg-1?mM-1 de LS foi adicionada ao VO2. Testes t pareados, correlaes pareadas e plotagem de Bland-Altman foram utilizados para investigar se os dois mtodos representam os mesmos fenmenos. RESULTADOS: Os principais achados foram que o Gc previsto para intensidades supramximas includos entre 110 e 160% ao correspondente ao pico de VO2 dos indivduos aumentou significativamente quando as medidas de LS foram includas nas regresses. A incluso das medidas de LS tambm aumentaram a impreciso do Gc a 110, 120, 130, 150 e 160%. CONCLUSO: Nossos resultados indicam que a incluso do equivalente do lactato de O2 na regresso de intensidade de VO2-exerccio aumenta o gasto energtico e diminui sua preciso.

  1. Superior high-rate capability of Na3(VO0.5)2(PO4)2F2 nanoparticles embedded in porous graphene through the pseudocapacitive effect.

    Science.gov (United States)

    Xiang, Xingde; Lu, Qiongqiong; Han, Mo; Chen, Jun

    2016-02-23

    Na3(VO0.5)2(PO4)2F2 nanoparticles embedded in porous graphene have been reported as a superior high-rate cathode material for sodium-ion batteries, exhibiting an excellent electrochemical performance with a high reversible capacity of 100 mA h g(-1) at 1 C, 77 mA h g(-1) at 50 C, and a capacity retention of 73% after 1000 cycles at 50 C. In particular, a significant contribution of the pseudocapacitive effect to the Na-storage capacity has been found for the first time. PMID:26853154

  2. A study of optical properties of Sm{sup 3+} ions in ?-Na{sub 3}Y(VO{sub 4}){sub 2} single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Sobczyk, Marcin, E-mail: marcin.sobczyk@chem.uni.wroc.pl; Szyma?ski, Damian

    2013-10-15

    Single crystals of ?-Sm{sup 3+}:Na{sub 3}Y(VO{sub 4}){sub 2} have been grown by the flux growth method. The absorption (300 K) fluorescence (4.2 and 300 K) and excitation (7 and 300 K) spectra as well as the fluorescence dynamics of the Sm{sup 3+}-doped title crystals are presented and analyzed in detail. The energy transfer between Sm{sup 3+}Sm{sup 3+} as well as from VO{sub 4}{sup 3?} to Sm{sup 3+} were studied in detail. A JuddOfelt intensity analysis of the absorption (300 K) spectrum has been applied for determination of ?{sub ?} parameters which in turn have been used in calculation of the radiative transition probability factor (A), fluorescence branching ratios (?), natural (radiative) lifetime of the {sup 4}G(4){sub 5/2} level of Sm{sup 3+} and emission cross-section (?{sub em}). For the first time very large lifetimes of the Sm{sup 3+} fluorescence level have been observed. -- Highlights: Single crystals of Sm{sup 3+}-doped ?-Na{sub 3}Y(VO{sub 4}){sub 2} have been grown by the flux growth method. The room and low-temperature spectroscopic properties of the single crystals were investigated. The decay time of the fluorescence level are larger than those earlier reported for some Sm{sup 3+} doped vanadate materials. Sm-doped ?-NYV crystal is a new promising luminescence materials.

  3. Theoretical studies of the optical and EPR spectra for VO^{2+} in Na_3C_6H_5O_72H_2O single crystal

    Directory of Open Access Journals (Sweden)

    Ch.-Y. Li

    2015-06-01

    Full Text Available On the basis of the perturbation formulas for a d^1 configuration ion in a tetragonal crystal field, the three optical absorption bands and electron paramagnetic resonance (EPR parameters (g factors g_i and hyperfine structure constants A_i for i = || and ?, respectively of VO^{2+} in Na_3C_6H_5O_72H_2O (TSCD single crystals were studied using the perturbation theory method. By simulating the calculated optical and EPR spectra to the observed values, local structure parameters and negative signs of the hyperfine structure constants A_i of the octahedral (VO_6^{8-} cluster in TSCD single crystal can be obtained.

  4. EVALUACIN DE NDICES DE CONVERSIN ENERGTICA EN LA PRODUCCIN DE GAS COMBUSTIBLE A PARTIR DE BIOMASA / EVALUATION THE RATES OF ENERGY CONVERSIONINTHE PRODUCTIONOFBIOMASSFUELGAS / DETERMINAOTAXAS DE CONVERSO DE ENERGIA NA PRODUO DE GS COMBUSTVEL DE BIOMASSA

    Scientific Electronic Library Online (English)

    GERARDO, CABRERA C.; SANTIAGO, MADRIAN M.; DEYANIRA, MUOZ M..

    2013-12-01

    Full Text Available Os rcios de converso de energia em gaseificao de biomassa, permite comparaes entre gaseificadores e decidir melhor desempenho em um processo industrial. A pesquisa utilizou um tipo de reactor experimental Imbert7 KW, a biomassa de bagao de cana, madeira e alfarrobeira. Elemental anlises fora [...] m realizadas e proximal, e os clculos de equilbrio de massa trmica na converso de taxas volumtricas de energia e de massa (I).Os valores calorficos de cada gs de biomassa, a uma temperatura mnima de 850 C e 1050 C a operao do reactor era ptimo: 3679 kJ / kg de carvo de alfarroba, 4,603 madeira Kj / Kg e 5.009 kJ / kg de bagao cana. Enquanto as taxas de utilizao volumtricasforam: carvo Kj/Nm3 alfarroba 3.509,39, 3.804,39 e 4.847,83 Kj/Nm3 bagao de madeira Kj/Nm3 cana. Conclumos eficincia gaseificador de 70%, a taxa de converso adequada para estimar a massa calorfica do gs combustvel produzido pode ser recuperado em um valor de aquecimento de combusto do gs de sntese poder cerca de 10% aquecimento a gs e perdas de calor so 30%. Abstract in spanish Los ndices de conversin energtica en la gasificacin de biomasa, permitecomparaciones entregasificadores y obtenerelmejor desempeo enun proceso industrial. Se utiliz un reactor de prueba tipo Imbert de 7 KW y biomasa debagazo de caa de azcar,madera y rbol de algarrobo. Se realizaron anlisis [...] elementales, proximalesy los balances msicos y trmicos en el clculo de los ndices de conversin de energa volumtrica y msica ().Los valores del poder calorfico del gas generado a una temperatura mnima de 850C y ptima de 1050C, en el reactor fueron: 3679 Kj/Kg de carbn de algarrobo, 4603 Kj/Kg de madera y 5009 Kj/Kg de bagazo de caa. Mientras los ndices de aprovechamiento volumtrico fueron: 3509,39 Kj/Nm3decarbn de algarrobo, 3804,39 Kj/Nm3demadera y4847,83 Kj/Nm3debagazo de caa de azcar. Se concluye que una eficacia del 70% en el gasificador, el ndice de conversin es apropiado para estimar el poder calorfico,la masa del gas producido combustible puede ser recuperada en una combustin, el poder calorfico del gas de sntesis es aproximadamente el 10% del poder calorfico de la gasolina y las prdidas de calor son del 30%. Abstract in english The energy conversion ratios in biomass gasification, allows comparisons between gasifiers and decide best performing one in an industrial process. The research used a test reactor type Imbert 7 KW, biomass sugarcane bagasse, wood and carob tree. Elemental and proximal analyzes were performed and th [...] ermal mass balance calculations involved in the conversion rates volumetric energy and mass (I). The calorific values of each biomass gas at a minimum temperature of 850C and 1050C optimum reactor operation where: 36779 kJ/kg of coal carob, 4603 kJ/kg of wood and 5009 kJ/kg of bagasse cane. While volumetric utilization rateswhere: 3509.39 of coal carob, 3804.39 Kj/Nm3 wood and 4847.83 Kj/Nm3 sugarcane bagasse. We conclude gasifies efficiency is 70%, the conversion rate is appropriate for estimating the calorific mass of the fuel gas produced can be recovered in a combustion heating value of the synthesis gas is about 10% power gas heating and heat losses are 30%.

  5. Predio da potncia aerbia (VO2mx de crianas e adolescentes em teste incremental na esteira rolante Prediction of aerobic power (VO2max of children and adolescents during an incremental treadmill test

    Directory of Open Access Journals (Sweden)

    Fabiana Andrade Machado

    2013-03-01

    Full Text Available O consumo mximo de oxignio (VO2mx a quantidade mxima de energia que pode ser produzida pelo metabolismo aerbio em determinada unidade de tempo, podendo ser determinado direta ou indiretamente atravs de equaes preditivas. O objetivo deste trabalho foi elaborar uma equao preditiva especfica para determinar o VO2mx de meninos de 10 a 16 anos. Quarenta e dois meninos realizaram teste ergoespiromtrico de corrida em esteira rolante com velocidade inicial de 9 km/h at exausto voluntria. Atravs da regresso linear mltipla foi possvel desenvolver a seguinte equao para a determinao indireta do VO2mx: VO2mx (ml/min = -1574,06 + (141,38 x Vpico + (48,34 * Massa corporal, com erro padro de estimativa = 191,5 ml/min (4,10 ml/kg/min e o coeficiente de determinao = 0,934. Sugerimos que esta uma frmula adequada para predizer o VO2mx para esta populao.The maximal oxygen uptake (VO2max is the maximal quantity of energy that can be produced by the aerobic metabolism in certain time unity. It can be determined direct or indirectly by predictive equations. The objective of this study was to make a specific predictive equation to determine the VO2max from boys aged 10-16 years-old. Forty-two boys underwent a treadmill running ergospirometric test, with the initial velocity set at 9 km/h, until voluntary exhaustion. By the multiple linear regression was possible to develop the following equation for the indirect determination of the VO2max: VO2max (ml/min = -1574.06 + (141.38 x Vpeak + (48.34 * Body mass, with standard error of estimate = 191.5 ml/min (4.10 ml/kg/min and coefficient of determination = 0.934. We suggest that this formula is appropriate to predict VO2max for this population.

  6. Predio da potncia aerbia (VO2mx) de crianas e adolescentes em teste incremental na esteira rolante / Prediction of aerobic power (VO2max) of children and adolescents during an incremental treadmill test

    Scientific Electronic Library Online (English)

    Fabiana Andrade, Machado; Benedito Srgio, Denadai.

    2013-03-01

    Full Text Available O consumo mximo de oxignio (VO2mx) a quantidade mxima de energia que pode ser produzida pelo metabolismo aerbio em determinada unidade de tempo, podendo ser determinado direta ou indiretamente atravs de equaes preditivas. O objetivo deste trabalho foi elaborar uma equao preditiva especf [...] ica para determinar o VO2mx de meninos de 10 a 16 anos. Quarenta e dois meninos realizaram teste ergoespiromtrico de corrida em esteira rolante com velocidade inicial de 9 km/h at exausto voluntria. Atravs da regresso linear mltipla foi possvel desenvolver a seguinte equao para a determinao indireta do VO2mx: VO2mx (ml/min) = -1574,06 + (141,38 x Vpico) + (48,34 * Massa corporal), com erro padro de estimativa = 191,5 ml/min (4,10 ml/kg/min) e o coeficiente de determinao = 0,934. Sugerimos que esta uma frmula adequada para predizer o VO2mx para esta populao. Abstract in english The maximal oxygen uptake (VO2max) is the maximal quantity of energy that can be produced by the aerobic metabolism in certain time unity. It can be determined direct or indirectly by predictive equations. The objective of this study was to make a specific predictive equation to determine the VO2max [...] from boys aged 10-16 years-old. Forty-two boys underwent a treadmill running ergospirometric test, with the initial velocity set at 9 km/h, until voluntary exhaustion. By the multiple linear regression was possible to develop the following equation for the indirect determination of the VO2max: VO2max (ml/min) = -1574.06 + (141.38 x Vpeak) + (48.34 * Body mass), with standard error of estimate = 191.5 ml/min (4.10 ml/kg/min) and coefficient of determination = 0.934. We suggest that this formula is appropriate to predict VO2max for this population.

  7. Incluso do equivalente do lactato sanguneo O2 na regresso de intensidade de exerccio VO2 aumenta o gasto energtico de corrida e diminui sua preciso / Inclusion of blood lactate O2 equivalent in the VO2 exercise intensity regression increases the energy cost of running and lowers its precision / La inclusin del equivalente del lactato sanguneo O2 en la regresin de intensidad de ejercicio VO2 aumenta el gasto energtico de la carrera y disminuye su precisin

    Scientific Electronic Library Online (English)

    Victor Machado, Reis; Diogo Roberto, Oliveira; Andr Luiz, Carneiro; Tiago Manuel, Barbosa.

    2013-12-01

    Full Text Available INTRODUO E OBJETIVOS: Investigar se a incluso do equivalente energtico de lactato sanguneo (LS) em intensidades submximas alteraria o gasto energtico de corrida (Gc) estimado para corrida supramxima de alta intensidade assim como sua preciso MTODOS: O Gc foi determinado a partir da curva d [...] e regresso de velocidade do VO2. Para cada sujeito, uma regresso alternativa foi estabelecida em que energia equivalente a 3 ml de O2 kg-1?mM-1 de LS foi adicionada ao VO2. Testes t pareados, correlaes pareadas e plotagem de Bland-Altman foram utilizados para investigar se os dois mtodos representam os mesmos fenmenos. RESULTADOS: Os principais achados foram que o Gc previsto para intensidades supramximas includos entre 110 e 160% ao correspondente ao pico de VO2 dos indivduos aumentou significativamente quando as medidas de LS foram includas nas regresses. A incluso das medidas de LS tambm aumentaram a impreciso do Gc a 110, 120, 130, 150 e 160%. CONCLUSO: Nossos resultados indicam que a incluso do equivalente do lactato de O2 na regresso de intensidade de VO2-exerccio aumenta o gasto energtico e diminui sua preciso. Abstract in spanish INTRODUCCIN Y OBJETIVOS: Investigar si la inclusin del equivalente energtico de lactato sanguneo (LS), en intensidades submximas, modificara el gasto energtico de la carrera (Gc), estimado para carrera supramxima de alta intensidad, as como su precisin. MTODOS: El Gc fue determinado a par [...] tir de la curva de regresin de velocidad del VO2. Para cada individuo, se estableci una regresin alternativa en la cual energa equivalente a 3 ml de O2 kg-1?mM-1 de LS fue adicionada al VO2. Pruebas t por pares, correlaciones por pares y plotaje de Bland-Altman fueron utilizados para investigar si los dos mtodos representan los mismos fenmenos. RESULTADOS: Los hallazgos principales fueron que el Gc previsto para intensidades supramximas, incluidos 110% y 160% de lo que corresponde al pico de VO2 de los individuos, aument significativamente cuando las medidas de LS fueron incluidas en las regresiones. La inclusin de las medidas de LS tambin aument la imprecisin del Gc a 110%, 120%, 130%, 150% y 160%. CONCLUSIN: Nuestros resultados indican que la inclusin del equivalente del lactato de O2, en la regresin de intensidad de VO2-ejercicio, aumenta el gasto energtico y disminuye su precisin. Abstract in english INTRODUCTION AND OBJECTIVES: Investigate whether the inclusion of the blood lactate (BL) energy equivalent at submaximal intensities would change the energy cost of running (CR) predicted to supramaximal high-intensity running as well as its precision. METHODS: The CR was determined from the slope o [...] f the VO2-speed regression. For each subject an alternative regression was established where an energy equivalent of 3 ml O2 kg-1?mM-1 BL was added to the VO2. Paired t-tests, pairwise correlations and Bland-Altman plots were used to investigate whether the two methods represent the same phenomena. RESULTS: The main findings were that CR predicted to supramaximal intensities comprised between 110% and 160% of that corresponding to the individuals' peak VO2, increased significantly when the BL measurements were included in the regressions. The inclusion of BL measurements also increased the imprecision of the CR at 110%, 120%, 130%, 150% and 160%. CONCLUSIONS: Our results indicate that inclusion of lactate O2 equivalent in the VO2-exercise intensity regression increases the energy cost of running and lowers its precision.

  8. Calefaccion centralizada por biomasa, Cullar

    Directory of Open Access Journals (Sweden)

    Verd Prez, Jess

    2001-10-01

    Full Text Available A plant of municipal central heating feeded with residual biomass, has been created in Cullar (Segovia, Spain, in order to demostrate its technical viability and to make more confortable the life of village inhabitants. Those residual biomass used as combustible, comes from the pine seeds, the key industry in the area. The calorific energy generated by combustion of those pine seeds, serves to heat the water to be send later through different pipes crossing the village. So, heating services and sanitary hot water are used according to the moment of the year. The study of the operative plant, allow us to discern the more adecuated operation parameters. reaching a total thermical yield of 60%. So its technical and economical viability concerning other traditional combustibles, its big environmental contribution to the production of energy, in addition to the social advantages -1ike the creation of new working jobs and the development of alternative activities in agricultura1 and forest areas- have contributed to present this plant as a model to be extended to other areas with potential biomass.Con el fin de demostrar su viabilidad tcnica y econmica y dar servicio a los habitantes de la localidad, se ha instalado en Cullar (Segovia, Espaa, una planta de calefaccin municipal alimentada con biomasa residual. Como combustible utiliza los residuos biomsicos procedentes de la industria pionera de la zona. La energa calorfica generada por el proceso de combustin de stos, calienta agua que es distribuida a travs de un circuito de tuberas aisladas a travs de la ciudad. Se proporcionan as los servicios de calefaccin y agua caliente sanitaria segn la poca del ao. El estudio de la operacin de la planta, ha permitido caracterizar los parmetros de funcionamiento ms adecuados. habindose obtenido un rendimiento trmico total de la instalacin del 60%. quedando justificada su viabilidad tcnica y econmica respecto a otros combustibles tradicionales. Su gran contribucin medioambiental a la produccin de energa. adems de las ventajas sociales como la creacin de puestos de trabajo y desarrollo de actividades alternativas en zonas agrcolas y forestales, hacen que esta instalacin sirva de modelo para su desarrollo en otras poblaciones con potencial de biomasa.

  9. VoIP Security

    OpenAIRE

    Fontanini, Piero

    2008-01-01

    VOIP or Voice Over Internet Protocol is a common term for phone service over IP based networks. There are much information about VoIP and some of how VoIP can be secured. There is however no standard for VoIP and no general solution for VoIP Security. The security in VoIP systems today are often non existing or in best case weak and often based on proprietary solutions. This master thesis investigates threats to VoIP system and describes existing alternatives for securing VoIP as it is today....

  10. New chemical route for the synthesis of ?-Na(0.33)V?O? and its fully reversible Li intercalation.

    Science.gov (United States)

    Kim, Jae-Kwang; Senthilkumar, B; Sahgong, Sun Hye; Kim, Jung-Hyun; Chi, Miaofang; Kim, Youngsik

    2015-04-01

    To obtain good electrochemical performance and thermal stability of rechargeable batteries, various cathode materials have been explored including NaVS2, ?-Na(0.33)V2O5, and Li(x)V2O5. In particular, Li(x)V2O5 has attracted attention as a cathode material in Li-ion batteries owing to its large theoretical capacity, but its stable electrochemical cycling (i.e., reversibility) still remains as a challenge and strongly depends on its synthesis methods. In this study, we prepared the Li(x)V2O5 from electrochemical ion exchange of ?-Na(0.33)V2O5, which is obtained by chemical conversion of NaVS2 in air at high temperatures. Crystal structure and particle morphology of ?-Na(0.33)V2O5 are characterized by using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy techniques. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy, in combination with electrochemical data, suggest that Na ions are extracted from ?-Na(0.33)V2O5 without irreversible structural collapse and replaced with Li ions during the following intercalation (i.e., charging) process. The thus obtained Li(x)V2O5 delivers a high discharge capacity of 295 mAh g(-1), which corresponds to x = 2, with crystal structural stability in the voltage range of 1.5-4.0 V versus. Li, as evidenced by its good cycling performance and high Coulombic efficiency (under 0.1 mA cm(-2)) at room temperature. Furthermore, the ion-exchanged Li(x)V2O5 from ?-Na(0.33)V2O5 shows stable electrochemical behavior without structural collapse, even at a case of deep discharge to 1.5 V versus Li. PMID:25768692

  11. Three-dimensional framework of uranium-centered polyhedra with non-intersecting channels in the uranyl oxy-vanadates A2(UO2)3(VO4)2O (A=Li, Na)

    International Nuclear Information System (INIS)

    The uranyl vanadates A2(UO2)3(VO4)2O (A=Li, Na) have been synthesized by solid-state reaction and the structure of the Li compound was solved from single-crystal X-ray diffraction. The crystal structure is built from ?1[UO5]4- chains of edge-shared U(2)O7 pentagonal bipyramids alternatively parallel to a-vector- and b-vector-axis and further connected together to form a three-dimensional (3-D) arrangement. The perpendicular chains are hung on both sides of a sheet ?2[(UO2)(VO4)2]4- parallel to (001), formed by U(1)O6 square bipyramids connected by VO4 tetrahedra, and derived from the autunite-type sheet. The resulting 3-D framework creates non-intersecting channels running down the a-vector- and b-vector-axis formed by empty face-shared oxygen octahedra, the Li+ ions are displaced from the center of the channels and occupy the middle of one edge of the common face. The peculiar position of the Li+ ion together with the full occupancy explain the low conductivity of Li2(UO2)3(VO4)2O compared with that of Na(UO2)4(VO4)3 containing the same type of channels half occupied by Na+ ions in the octahedral sites. Crystallographic data for Li2(UO2)3(VO4)2O: tetragonal, space group I41/amd, a=7.3303(5)A, c=24.653(3)A, V=1324.7(2)A3, Z=4, ?mes=5.32(2)g/cm3, ?cal=5.36(3)g/cm3, full-matrix least-squares refinement basis on F2 yielded, R1=0.032, wR2=0.085 for 37 refined parameters with 364 independent reflections with I>=2?(I)

  12. A phase-transfer assisted solvo-thermal strategy for low-temperature synthesis of Na3(VO1-xPO4)2F1+2x cathodes for sodium-ion batteries.

    Science.gov (United States)

    Zhao, Junmei; Mu, Linqin; Qi, Yuruo; Hu, Yong-Sheng; Liu, Huizhou; Dai, Sheng

    2015-04-28

    We demonstrate that a series of high-performance cathode materials, sodium vanadium polyanionic compounds, Na3(VO1-xPO4)2F1+2x (x = 0, 0.5 and 1), can be synthesized by a phase-transfer assisted solvo-thermal strategy at a rather low temperature (80-140 C) in one simple step, exhibiting a high Na storage capacity of ca. 120 mA h g(-1) and excellent cycling performance. This study makes a significant step to extend this strategy to the synthesis of functional materials from simple binary to complex multicomponent compounds. PMID:25812049

  13. Benefcios do Uso do VoIP: um estudo de caso na GMBenefits from the VOIP Use: a case study at GMBeneficios del Uso del VoIP: un estudio de caso en la GM

    Directory of Open Access Journals (Sweden)

    FEITERA, Carlos Henrique

    2006-05-01

    Full Text Available RESUMOEste artigo traz uma viso do que o VoIP, assim como suas principais aplicaes, os fatores que as empresas buscam para minimizar custos em telefonia, as vantagens e desvantagens, a agregao de novas tecnologias, como WI-FI e o VOIP, e o futuro da telefonia no Brasil.Sero analisadas as diferenas entre Telefonia IP e VOIP paralelamente, e ser tratada como base e estudo de caso a empresa General Motors do Brasil. O objetivo mostrar o contedo que envolve essa inovadora tecnologia. Podemos dizer que a vontade de abordar esse tema foi despertada no somente por ser uma tecnologia inovadora que vem substituindo a telefonia convencional reduzindo os custos das empresas e trocando servios e equipamentos obsoletos por uma srie de novos servios e oferecendo muitos recursos e benefcios, mas nos chamou a ateno tambm pelo fato de ser uma tecnologia que est revolucionando o mercado de telecomunicaes, j que as empresas de telefonia prestadoras de servios consomem uma boa parte da renda das empresas e pessoas, e tambm por exigir, nesse perodo de transio, muita habilidade em adequar as necessidades do cliente ao uso dessas ferramentas.ABSTRACTThis article brings a vision about Voip, as well as itself main applications, the factors with that the companies search to decrease costs in telephony, the advantages and disadvantages, aggregation of new technologies as wi-fi to the VOIP and the future of the telephony in Brazil. The differences between Telephony IP and VOIP will be analyzed parallel, and will be showed with as base study case of the General Motors. Our objective for this subject is to show the content that involves this fantastic technology. We can say that will to approach this subject it was influenced not only by being an innovative technology that comes substituting the conventional telephony, reducing the costs of the companies, and changing to services and obsolete equipments for a series of new services offering many resources and benefits, but it also called-us the attention for the fact being a technology whom making a revolution in telecommunications market where the rendering companies of telephony of services consumes a good part of the income of the companies and people, and also for This article brings a vision about VOIP, as well as its main applications, the factors with that the companies search to decrease costs in telephony, the advantages and disadvantages, aggregation of new technologies as wi-fi to the VOIP and the future of the telephony in Brazil. The differences between Telephony IP and VOIP will be analyzed in parallel, and will be showed having as base a case study of the General Motors. Our objective for this subject is to show the content that involves this fantastic technology. We can say that the will to approach this subject was influenced not only by being an innovative technology that comes to substitute the conventional telephony, reducing the costs of the companies, and changing services and obsolete equipment for a series of new services offering many resources and benefits, but it also called us the attention for the fact that this is a technology making a revolution in telecommunications market where the rendering companies of telephone services consumes a good part of the income of the companies and people, and also for demanding in this period of transition a great deal of ability to adequate the necessities of the customer to use of these tools and resources.RESUMENEste artculo aporta una visin de lo que es el VoIP, sus principales aplicaciones, los factores que las empresas buscan para minimizar costos en telefona, las ventajas y desventajas, el agregado de nuevas tecnologas, como WI-FI y el VOIP y el futuro de la telefona en Brasil.Se analizarn las diferencias entre Telefona IP y VOIP y se tratar como base y estudio de caso la empresa General Motors de Brasil. La finalidad es mostrar el contenido que comprende esta innovadora tecnologa. Podemos decir que el inters en este tema surgi prim

  14. PRETRATAMIENTOS DE LA CELULOSA Y BIOMASA PARA LA SACARIFICACIN

    Directory of Open Access Journals (Sweden)

    ANDERSON GUARNIZO FRANCO

    2009-01-01

    Full Text Available La biomasa celulsica se ha vuelto un producto interesante para ser aprovechada como materia prima en la fabricacin de biocombustibles, especialmente el etanol. El paso crtico en su conversin a etanol, implica la degradacin de los polisacridos a azcares fermentables, en un proceso denominado sacarificacin. La celulosa, el componente principal de la biomasa, es un polisacrido de difcil degradacin en condiciones de tratamiento moderadas. Las investigaciones ms recientes en el campo de los biorecursos, se han enfocado hacia el desarrollo de ciertos pretratamientos de la biomasa o la celulosa bajo los cuales se logra que estos materiales sean de ms fcil degradacin a azcares fermentables. El presente artculo resume los resultados ms sobresalientes, sin ser exhaustivos, de los pretaratimentos de la celulosa y la biomasa para su conversin a productos fermentables por la ruta etanlica.

  15. Potencial de produccin de biomasa en una poblacin natural de la ostra crassostrea rhizophorae, en la laguna grande de obispo, Golfo de Cariaco, Venezuela / Biomass production potential in a natural population of the oyster crassostrea rhizophorae in laguna grande de obispo; Cariaco Gulf; Venezuela / Potencial de produo de biomassa na populao natural da ostra crassostrea rhizophorae, na lagoa grande de obispo, Golfo de Cariaco, Venezuela

    Scientific Electronic Library Online (English)

    Antulio, Prieto; Andrs, Montes; Lilia J, Ruiz.

    2008-10-08

    Full Text Available A ostra Crassostrea rhizophorae um bivalves de interesse comercial, comum nas comunidades de manglares no oriente da Venezuela. Para avaliar o potencial de gerao de biomassa da espcie se realizaram amostras mensais desde maio de 2002 at maio de 2003, em duas estaes da populao natural de La [...] guna Grande do Obispo, estado Sucre, Venezuela. Utilizando um desenho de amostras aleatrio simples se determinou a abundncia e a biomassa de bivalves fixados a razes de Rhizophora manglae, estimando a produo secundria pelo mtodo da taxa especfica de crescimento. Determinou-se uma densidade mdia de 818,13ind/m de raiz com biomassa mdia em peso seco de 662,39g/m, sem diferenas significativas entre estaes nem meses. Utilizando um modelo de crescimento com parmetros finais de L= 87,68 e K= 0,19/ms, se obteve uma produo secundria total de 2.355,546g/m/ano, sendo o intervalo de tamanho 50,01-60,00mm o que aportou a maior quantidade (382,353g/m/ano). A mxima produo se obteve em jan-fev de 2003 (243,906g/m/ano) e a mnima em mai-jun de 2002 (100,80g/m/ano). A produo por indivduo foi de 43,283g/m/ano com a mesma tendncia temporal da total. Ainda que no se determinasse correlao dos incrementos de produo com a temperatura e salinidade, a maior produo ocorreu durante a poca de surgncia costeira na zona. A relao produo/biomassa foi de 3,55/ano, resultados que indicam que C. rhizophorae apresenta um grande potencial para atividades de aqicultura na zona por sua reproduo continua e altas taxas de crescimento e produtividade. Abstract in spanish La ostra Crassostrea rhizophorae es un bivalvo de inters comercial, comn en las comunidades de manglar en el oriente de Venezuela. Para evaluar el potencial de generacin de biomasa de la especie se realizaron muestreos mensuales desde mayo 2002 hasta mayo 2003, en dos estaciones de la poblacin n [...] atural de Laguna Grande del Obispo, estado Sucre, Venezuela. Utilizando un diseo de muestreo al azar simple se determin la abundancia y la biomasa de bivalvos fijados a races de Rhizophora manglae, estimando la produccin secundaria por el mtodo de la tasa especfica de crecimiento. Se determin una densidad promedio de 818,13ind/m de raz con biomasa promedio en peso seco de 662,39g/m, sin diferencias significativas entre estaciones ni meses. Utilizando un modelo de crecimiento con parmetros finales de L= 87,68 y K= 0,19/mes, se obtuvo una produccin secundaria total de 2355,546g/m/ao, siendo el intervalo de talla 50,01-60,00mm el que aport la mayor cantidad (382,353g/m/ao). La mxima produccin se obtuvo en ene-feb 2003 (243,906g/m/ao) y la mnima en may-jun 2002 (100,80g/m/ao). La produccin por individuo fue de 43,283g/m/ao con la misma tendencia temporal de la total. Aunque no se determin correlacin de los incrementos de produccin con la temperatura y salinidad, la mayor produccin ocurre durante la poca de surgencia costera en la zona. La relacin produccin/biomasa fue de 3,55/ao, resultados que indican que C. rhizophorae presenta un gran potencial para actividades de acuicultura en la zona por su reproduccin continua y altas tasas de crecimiento y productividad. Abstract in english The oyster Crassostrea rhizophorae is a bivalve of commercial interest, common in mangrove communities of eastern Venezuela. This study was conducted in order to evaluate the production of biomass of species in a natural population of Laguna Grande de Obispo, Cariaco Gulf, Venezuela. Monthly samplin [...] gs were carried out between May 2002 and May 2003 in two stations. Using a simple random sampling design, the abundance and biomass of bivalves fixed on mangrove roots Rhizophora manglae were determined, estimating the secondary production by the specific growth rate method. Mean density was 818.13ind/m and mean biomass was 662.39g/m of root, without significant differences between stations and months. Using a gr

  16. Latest VO developments at Paris VO Data Center

    Science.gov (United States)

    Le Sidaner, P.; Dubernet, M.-L.; Simon, G.; Aboudarham, J.; Baillard, A.; Barache, C.; Boone, F.; Chilingarian, I.; Dantel-Fort, M.; Desert, J. M.; Didelon, P.; Egret, D.; Guibert, J.; Hebrard, G.; Lainey, V.; Magnard, F.; Marmo, C.; Martin, J. M.; Pelat, D.; Reni, C.; Sarkissian, A.; Schneider, J.; Theureau, G.; Vachier, F.

    2006-06-01

    Paris VO Data Center aims at providing VO access to its databases ressources, at participating to international standards developments, at implementing VO compliant simulation codes and data visualisation and analysis softwares. We will present some of the latest VO developments involving ressources from Paris VO Data Center, i.e, the first simple spectra access for data of the Nanay radiotelescope observatory, a validator for Simple Spectra Access protocols and its implementation tools, a Cone-search access to the exoplanet catalog, a pipeline for images processing to make them "science-ready" in vo-format, implementation of Simple Image Access using Geographic Information System in databases. Developments involving other ressources may be found in their own contributions to this meeting.

  17. Latest VO development at VO-Paris Data Centre

    Science.gov (United States)

    Le Sidaner, P.; Dubernet, M.-L.; Simon, G.; Aboudarham, J.; Baillard, A.; Barache, C.; Boone, F.; Chilingarian, I.; Dantel-Fort, M.; Didelon, P.; Egret, D.; Guibert, J.; Hebrard, G.; Lainey, V.; Magnard, F.; Marmo, C.; Martin, J. M.; Normand, J.; Pelat, D.; Reni, C.; Sarkissian, A.; Savalle, R.; Shih, A.; Schneider, J.; Theureau, G.; Vachier, F.

    2007-07-01

    VO-Paris Data Center aims at providing VO access to its databases resources, at participating to the development of interoperability standards, at implementing VO-compliant simulation codes and data visualization and analysis software. We will present some of the latest VO development involving resources from Paris VO Data Center, i.e, the first simple spectral access for data of the Nancay radio-telescope, a validator for Simple Spectra Access protocols and its implementation tools, a Cone-search access to the exoplanet catalog, a pipeline for image processing to make them "science-ready" and converting into VO-format, implementation of Simple Image Access using Geographic Information System in databases. Developments involving other resources may be found in their own contributions to this meeting.

  18. Utjecaj alkohola na u?inak u zadatku sljepo?e zbog nepanje u simuliranoj situaciji vonje automobila

    Directory of Open Access Journals (Sweden)

    Andro Pavuna

    2012-05-01

    Full Text Available Akutna konzumacija etilnoga alkohola tetno utje?e na brojne vidne funkcije. U ovom smo se istraivanju usredoto?ili na specifi?ne procese vidne percepcije i panje te utjecaj relativno niskih razina alkohola na njih. U istraivanju je sudjelovalo 47 studenata raznih fakulteta Sveu?ilita u Zagrebu. Sudionici u eksperimentalnoj skupini (N=22 konzumirali su alkoholni koktel stopostotnoga naran?inog soka i votke kako bi dostigli ciljanu razinu alkohola u krvi od 0.8 g/kg, dok su sudionici u kontrolnoj skupini (N=25 konzumirali placebo samo naran?in sok sa snanom aromom etilnoga alkohola. Nakon konzumacije pi?a sudionici su rjeavali zadatak vidne percepcije i panje koji se sastojao od kratkoga video-isje?ka koji prikazuje reiranu realnu prometnu situaciju u kojoj jedno vozilo slijedi drugo s centralnim zadatkom brojanja paljenja ''top'' svjetala na vozilu koje se kre?e ispred njega, te percepcije zna?ajnih objekata i detalja iz okoline poput dje?jih kolica, djeteta koje prelazi cestu, prometnih zakova i sl. Provedenim je istraivanjem utvr?eno kako sudionici pod utjecajem alkohola postiu statisti?ki zna?ajno slabiji rezultat u zadatku vidne percepcije od sudionika koji nisu pod utjecajem alkohola. Dobiven je umjereni efekt u kumulativnom zadatku vidne percepcije i panje, te nezna?ajan, ali jasan trend tetnoga utjecaja alkohola na pojedine zadatke vidne percepcije i panje.

  19. ESTIMACIN DE BIOMASA AREA EN CULTIVOS CON SENSORES REMOTOS

    Directory of Open Access Journals (Sweden)

    Ferm\\u00EDn Pascual-Ram\\u00EDrez

    2012-01-01

    Full Text Available Para estimar la produccin de biomasa area en cultivos utilizando sensores remotos se realizaron anlisis de la produccin de biomasa e informacin espectral en cinco cultivos medidos en campo, durante una campaa de muestreo en el Valle del Yaqui, Sonora. La informacin espectral fue procesada hasta la obtencin del ndice de vegetacin iso-suelo (IVIS. Los anlisis multitemporales muestran un comportamiento similar entre el desarrollo de los cultivos y el valor del IVIS, por lo que se obtuvo una relacin lineal entre ellos. De manera similar fueron analizados el ndice de cosecha y su relacin con el IVIS. Los resultados mostraron que el IVIS es un ndice adecuado para la estimacin de biomasa y rendimiento en cultivos.

  20. Solid Biomass Consumption in Households and Greenhouse Gas Emission Reduction in Latvia / CIET?S Biomasas PAT?RI? un SILTUMN?CEFEKTA G?ZU Emisiju SAMAZIN?ANAS PERSPEKT?VA Latvijas M?JSAIMNIEC?B?S

    Science.gov (United States)

    Kudrenickis, I.; Klavs, G.

    2013-12-01

    Utilisation of biomass is an important factor in reducing emission of greenhouse gases (GHG); at the same time, high efficiency of biomass combustion technologies is to be ensured to minimise the methane (CH4) emission thus achieving the most efficient reduction in the total GHG emission. The authors analyse the GHG emission breakdown in Latvia among the sectors not included in the EU Emissions Trading Scheme (ETS), and, in the context of emission reduction, evaluate the energy supply in the Latvian household sector, the types of combustion technologies and the used fuels. The trend is considered for the CH4 emission factor during 1990-2010 in the household sector of EU countries, and the numerical index is calculated which illustrates decoupling the consumption of biomass fuel from CH4 emission. To evaluate the perspective of CH4 emission reduction in the Latvian household sector, two scenarios are investigated for efficiency improvement as related to the central heating equipment based on wood fuel. Biomasas izmantoana ir viens no principi?lajiem virzieniem siltumn?cefekta g?zu (SEG) emisiju samazin?an?. Maksim?la SEG emisiju samazin?juma pan?kanai ir nepiecieams nodroin?t biomasas sadedzin?anas iek?rtu augstu efektivit?ti, lai minimiz?tu ar biomasas kurin?m? pat?ri?u saist?to met?na (CH4) emisiju pieaugumu. Autori raksturo Eiropas Savien?bas (ES) Emisiju kvotu tirdzniec?bas sist?mas (ETS) un taj? neietilpstoo sektoru (ne-ETS) noz?mi Latvijas SEG emisiju veidoan?, SEG emisiju relat?vo sadal?jumu atbilstoi da?diem ne- ETS sektoriem un SEG emisiju samazin?anas kontekst? analiz? Latvijas m?jsaimniec?bu sektora energoapg?di, pat?r?to kurin?mo un izmantot?s kurin?m? sadedzin?anas tehnolo?ijas. Rakst? ir demonstr?ta SEG emisiju inventariz?cij? pielietot? CH4 emisiju specifisk? faktora m?jsaimniec?bu sektora koksnes kurin?majam skaitlisko v?rt?bu dinamika 1990-2010 gados da?d?s ES valst?s. Sal?dzinot kurin?m? pat?ri?a un CH4 emisiju apjoma izmai?as, ir apr??in?ts skaitliskais r?d?t?js, kas raksturo biomasas kurin?m? pat?ri?a un CH4 emisiju "atsaisti" ES valst?s analiz?jam? laika posm?. Lai kvantitat?vi nov?rt?tu CH4 emisiju samazin?anas perspekt?vu Latvijas m?jsaimniec?bu sektor?, autori analiz? divus att?st?bas scen?rijus, kas paredz da?dus m?jsaimniec?bu centr?laj? apkur? izmantoto koksnes sadedzin?anas iek?rtu efektivit?tes pieaugumus.

  1. ECUACIONES ALOMTRICAS PARA ESTIMAR BIOMASA Y CARBONO EN Quercus magnoliaefolia

    Directory of Open Access Journals (Sweden)

    Jess D. Gmez-Daz

    2011-01-01

    Full Text Available En el ejido El Zapote de la Reserva de la Biosfera "Sierra de Huautla", estado de Morelos, Mxico, se seleccionaron doce rboles de Quercus magnoliaefolia Ne y se determin su biomasa en la parte area. El modelo alomtrico qued expresado como: B = 0.0345 * DAP2.9334 en donde B es la biomasa (kg y DAP es el dimetro a la altura del pecho (cm, con un coeficiente de determinacin (R2= 0.98; P<0.001. Adicionalmente, se estim la biomasa mediante una regresin lineal mltiple que consider el rea basal (AB, la densidad especfica de la madera (DEM y la altura de los rboles (H. Una alta proporcin de la varianza de la biomasa fue explicada solamente por el rea basal. La DEM y H no incrementaron significativamente la precisin de los modelos. El porcentaje promedio de carbono en los rboles de Q. magnoliaefolia fue de 47.14 con valores de 46.29 % para el fuste, 46.83 % para las ramas y 48.31 % para el follaje. La proporcin promedio de los componentes de la especie estudiada fue de 2.5 % para el fuste, 27.8 % para las ramas y 9.6 % para el follaje.

  2. VoWiFi Roaming

    OpenAIRE

    Muhammad Ali, Syed

    2006-01-01

    Freedom is humans natural instinct, which was limited by Ethernet and Fixed Telephony Era. With the emergence of new technologies like wireless fidelity (WiFi) and voice over IP (VoIP) humans once again have freedom of movement; which at the very same time provides enough reasons to change the market dynamics of communication industry. The buzz of Voice over WiFi (VoWiFi) in recent years indicates that VoWiFi is shaping up as the next big challenge to traditional telephony, not only due to c...

  3. Modelos matemticos y experimentales sobre el secado de biomasa

    Directory of Open Access Journals (Sweden)

    Jorge Armando Villalba Vidales

    2015-01-01

    Full Text Available El secado de biomasa como proceso previo a la combustin se ha convertido en la actualidad en un factor decisivo para mejorar la eficiencia de dichos procesos en los sectores industrial y residencial. Debido a la creciente importancia de este proceso, los investigadores han desarrollado una gran cantidad de modelos, tanto tericos como experimentales, que buscan predecir la cintica de secado de diferentes tipos de biomasa. Si bien se han logrado grandes avances en el desarrollo de modelos, an no existe un modelo unificado que permita predecir los perfiles de temperatura y humedad para diversos materiales. Dichas dificultades se generan fundamentalmente por la amplia diversidad de biomateriales y las grandes diferencias entre los procesos existentes. El propsito de este artculo es brindar una panormica sobre el estado del arte relativo a modelos, tanto matemticos como experimentales, utilizados en la actualidad para simular procesos de secado de la biomasa. Asimismo, proponer los elementos fundamentales que deber poseer un modelo de secado unificado.

  4. VO for Education: Archive Prototype

    Science.gov (United States)

    Ramella, M.; Iafrate, G.; De Marco, M.; Molinaro, M.; Knapic, C.; Smareglia, R.; Cepparo, F.

    2014-05-01

    The number of remote control telescopes dedicated to education is increasing in many countries, leading to correspondingly larger and larger amount of stored educational data that are usually available only to local observers. Here we present the project for a new infrastructure that will allow teachers using educational telescopes to archive their data and easily publish them within the Virtual Observatory (VO) avoiding the complexity of professional tools. Students and teachers anywhere will be able to access these data with obvious benefits for the realization of grander scale collaborative projects. Educational VO data will also be an important resource for teachers not having direct access to any educational telescopes. We will use the educational telescope at our observatory in Trieste as a prototype for the future VO educational data archive resource. The publishing infrastructure will include: user authentication, content and curation validation, data validation and ingestion, VO compliant resource generation. All of these parts will be performed by means of server side applications accessible through a web graphical user interface (web GUI). Apart from user registration, that will be validated by a natural person responsible for the archive (after having verified the reliability of the user and inspected one or more test files), all the subsequent steps will be automated. This means that at the very first data submission through the webGUI, a complete resource including archive and published VO service will be generated, ready to be registered to the VO. The efforts required to the registered user will consist only in describing herself/himself at registration step and submitting the data she/he selects for publishing after each observation sessions. The infrastructure will be file format independent and the underlying data model will use a minimal set of standard VO keywords, some of which will be specific for outreach and education, possibly including VO field identification (astronomy, planetary science, solar physics). The VO published resource description will be suggested such as to allow selective access to educational data by VO aware tools, differentiating them from professional data while treating them with the same procedures, protocols and tools. The whole system will be very flexible, scalable and with the objective to leave as less work as possible to humans.

  5. Synthesis, characterization and catalytic activity of two novel cis-dioxovanadium(v) complexes: [VO2(L)] and [VO2(Hlox)

    Scientific Electronic Library Online (English)

    Natlia M. L., Silva; Carlos B., Pinheiro; Eluzir P., Chacon; Jackson A. L. C., Resende; Jos Walkimar de M., Carneiro; Tatiana L., Fernndez; Marciela, Scarpellini; Mauricio, Lanznaster.

    Full Text Available Dois novos complexos [VO2(L)] e [VO2(HLox)] foram sintetizados e caracterizados por espectroscopias no IV, UV-Vis e RMN, voltametria cclica, anlise elementar e difrao de raios X. A sntese do ligante indito H2Lox tambm descrita. Os complexos 1 e 2 foram obtidos pela reao de [VO(acac)2] com [...] os respectivos ligantes HL e H2Lox. Alternativamente, 2 foi preparado a partir da reao de HL com [VO(acac)2] na presena de hidroxilamina, e atravs da reao de 1 com hidroxilamina. Dados cristalogrficos mostram que 1 e 2 apresentam estruturas moleculares similares, onde o centro de vandio(V) cis-dioxo encontra-se coordenado em um ambiente octadrico distorcido formado pelos ligantes L- e HLox-, respectivamente. A atividade cataltica destes compostos foi avaliada na oxidao do cicloexano, utilizando H2O2 e t-BuOOH como oxidantes. Ambos apresentam seletividade > 70% para formao de cicloexilidroperxido. Clculos B3LYP/6-31G(d) foram empregados na otimizao da geometria e para auxiliar na atribuio do espectro eletrnico. Abstract in english Two novel complexes, [VO2(L)] (1) and [VO2(HLox)] (2), were synthesized and characterized by IV, UV-Vis and NMR spectroscopy, cyclic voltammetry, elemental analysis and X-ray diffraction. The synthesis of a new ligand, H2Lox, is also described. Complexes 1 and 2 were obtained by the reaction of [VO( [...] acac)2] with the ligands HL and H2Lox, respectively. Alternatively, 2 was also obtained by the reaction of HL with [VO(acac)2] in the presence of hydroxylamine, and by the reaction of 1 with hydroxylamine. Crystallographic data show that complexes 1 and 2 have similar molecular structures, in which the cis-dioxovanadium(V) center is coordinated to L- or HLox-, respectively, in a distorted octahedral environment. The catalytic activity of these compounds towards cyclohexane oxidation was evaluated using H2O2 and t-BuOOH as oxidants. Both complexes presented > 70% selectivity for cyclohexylhydroperoxide formation. B3LYP/6-31G(d) calculations were used to confirm the geometry and to help assign the electronic spectra.

  6. Remocin y recuperacin de cromo (III) de soluciones acuosas por biomasa de sorgo

    OpenAIRE

    I. Cano Rodrguez; Prez, J.A.; Gutirrez, M.; J. L. Gardea

    2002-01-01

    En este trabajo se investig la capacidad de la biomasa de desecho de sorgo para remover y recuperar iones de cromo(III) de soluciones acuosas, tanto en sistemas en lote como en flujo continuo. Los resultados muestran que los iones de cromo(III) se unen preferentemente a la biomasa de sorgo a pH 4.5-5, despus de 15 minutos de contacto, con una capacidad de saturacin de aproximadamente 10 mg/g de biomasa seca. La biomasa inmovilizada fue capaz de remover y recuperar eficientemente iones de c...

  7. Importancia energtica y ambiental de la biomasa en colombia

    OpenAIRE

    Hernndez Luis Alfredo

    2011-01-01

    Entindase por energa de la biomasa aqulla que se origina al procesar parcial o totalmente cualquier sustancia o materia originada a travs del proceso de fotosntesis de los vegetales. Luego comprende especies y microespecies que cumplen para el hombre y el ecosistema una funcin especial ...

  8. VO2mx estimado e sua velocidade correspondente predizem o desempenho de corredores amadores / Estimated VO2max and its corresponding velocity predict performance of amateur runners

    Scientific Electronic Library Online (English)

    Tony Meireles, Santos; Allan Inoue, Rodrigues; Camila Coelho, Greco; Alan Lima, Marques; Bruno Souza, Terra; Bruno Ribeiro Ramalho, Oliveira.

    Full Text Available Observa-se, nos ltimos anos, um importante crescimento do nmero de praticantes de corrida com proporcional aumento da adeso destes s provas de rua. Nesta populao, a identificao dos determinantes do desempenho parece ser necessria para otimizao do tempo dedicado ao treinamento. O objetivo [...] do estudo foi estabelecer a associao do consumo mximo de oxignio (VO2mx) estimado, da velocidade crtica (VC) e da velocidade do VO2mx (V VO2mx), com os desempenhos nas provas de 3,6 km em subida e 10 e 21,1 km no plano. Doze corredores amadores (9 homens) com 36 5 anos de idade foram submetidos a quatro testes: 1 e 5 km de corrida, no plano; 3,6 km de corrida, com inclinao (?8%); e um teste para determinao indireta do VO2mx. A VC foi determinada atravs da relao linear entre a distncia e o tempo de corrida dos dois primeiros testes. Os sujeitos participaram de duas provas oficiais de 10 km e 21,1 km. A V VO2mx foi estimada a partir do VO2mx, atravs de equaes metablicas. O VO2mx apresentou a melhor associao com o desempenho da corrida em 10 e 21,1 km no plano. J na subida, a V VO2mx apresentou melhor associao. Considerando todas as provas, a varivel com maior mdia associativa foi o VO2mx (0,910,07), seguido do V VO2mx (0,900,04) e VC (0,870,06), respectivamente. Este estudo demonstrou elevadas associaes entre variveis fisiolgicas estabelecidas por mtodos indiretos, de baixo investimento e alta praticidade, com o desempenho da corrida em 10 e 21,1 km, no plano, e 3,6 km, em subida. Abstract in english In recent years, there has been a substantial increase in the number of runners, with a proportional increase in their involvement in amateur street competition. Identification of the determinants of performance in this population appears necessary for optimization of time devoted to training. The o [...] bjective of this study was to ascertain the association between estimated maximal oxygen uptake (VO2max), critical velocity (CV) and VO2max velocity (V VO2max) and athletic performance in the 3.6 km (uphill) and 10 and 21.1 km (flatland) events. Twelve amateur runners (nine male), mean age 36 5 years underwent five tests: 1 and 5 km race on level ground, 3.6 km race with slope (?8%), and indirect VO2max measurement. CV was determined from the linear relationship between distance and run time on the first two tests. The subjects then took part in two official 10 km and 21.1 km (half marathon) races. V VO2max was calculated from the VO2max through a metabolic equation. VO2max showed the best association with running performance in the 10 and 21.1 km events. For the uphill race, V VO2max showed a better association. Overall, the variable with the highest average association was VO2max (0.910.07), followed by V VO2max (0.900.04) and VC (0.870.06). This study showed strong associations between physiological variables established by low-cost, user-friendly indirect methods and running performance in the 10 and 21.1 km (flatland) and 3.6 km (uphill) running events.

  9. Performance of VoIP on HSDPA

    DEFF Research Database (Denmark)

    Wang, Bang; Pedersen, Klaus I.; Kolding, Troels E.; Mogensen, Preben E.

    This paper provides packet scheduler design and performance simulations for running VoIP services over high-speed downlink packet access (HSDPA) in WCDMA. The main challenge of supporting VoIP service on HSDPA is the tight delay requirement combined with the small VoIP packet size. A packet sched...

  10. Estimacin de biomasa por mtodos alomtricos, nutrimentos y carbono en plantaciones de palmito en Costa Rica

    Directory of Open Access Journals (Sweden)

    Adri\\u00E1n Ares

    2002-01-01

    Full Text Available El agroecosistema de palmito (Bactris gasipaes es un sistema de produccin sostenible en los trpicos hmedos. Los mtodos alomtricos permiten predecir la produccin de biomasa en forma no destructiva en cualquier momento y a partir de este dato determinar las fases de crecimiento del cultivo, los componentes de la biomasa y los nutrimentos asociados a cada componente, as como el rendimiento econmico esperado de una plantacin. Los objetivos generales del presente trabajo fueron obtener y validar funciones de prediccin de la biomasa seca y de palmitos producidos en plantaciones comerciales, para correlacionarlos con la biomasa y la produccin comercial de palmitos en las mismas. De esta manera, en varias fincas de la regin Atlntica de Costa Rica se cosech plantas de palmito y se separ sus componentes: follaje, pecolos y tallos. Se utiliz modelos de regresin no lineales para calcular en forma independiente los coeficientes de las ecuaciones y as estimar los componentes de la biomasa y de la biomasa total. El dimetro basal fue una variable ms efectiva para predecir la produccin de biomasa que la altura hasta la hoja candela, la altura total y el nmero de

  11. Investigation of VoIP and implementation

    OpenAIRE

    Ede, Aghedo

    2011-01-01

    Voice over Internet Protocol (VoIP) is the technology used to transmit conversations digitally over the Internet. VoIP is being adopted globally and changing the landscape of telecommunications for businesses and consumers. This thesis describes the investigation of VoIP and how it compares to traditional phone systems, voice characteristics, implementation challenges, digital voice process, testing and result, the standards organizations promoting the technology, and what this means for us ...

  12. VoIP Technology: Security Issues Analysis

    OpenAIRE

    Lazzez, Amor

    2013-01-01

    Voice over IP (VoIP) is the technology allowing voice and multimedia transmissions as data packets over a private or a public IP network. Thanks to the benefits that it may provide, the VoIP technology is increasingly attracting attention and interest in the industry. Actually, VoIP allows significant benefits for customers and communication services providers such as cost savings, rich media service, phone and service portability, mobility, and the integration with other ap...

  13. VO2 films as active infrared shutters

    OpenAIRE

    Johansson, Daniel

    2006-01-01

    An active optical shutter for infrared light (3-5 ?m) has been designed, exploiting the phase transition in thermochromic vanadium dioxide (VO2). A spin coating processing route for VO2 films has been adapted to manufacture reproducible depositions onto sapphire (Al2O3) substrates. The VO2 films have been characterized by X-ray powder diffraction (XRPD) and infrared spectroscopy (FTIR), showing 55 % transmittance in the open mode and 0.1 % in the closed mode. The VO2 film temperature determin...

  14. Validade preditiva da medida e estimativas do VO2mx no desempenho de Mountain Bikers

    Directory of Open Access Journals (Sweden)

    Fernanda Mainardi

    2015-02-01

    Full Text Available INTRODUO: considerando o racional para a utilizao das equaes preditivas na estimativa do VO2mx em atletas, nenhum estudo estabeleceu sua validade para o desempenho no mountain bike cross-country (XCO. OBJETIVO: comparar diferentes estratgias de determinao do VO2mx, de forma direta ou indireta, para a predio do desempenho em uma prova real e outra simulada. MTODOS: 20 atletas de XCO do sexo masculino (31,6 6,8 anos; 68,1 6,5 kg; 175,5 5,7cm; 64,9 4,4 mL. kg-1.min-1, foram submetidos a trs sesses experimentais. A primeira visita consistiu na estratificao de risco, avaliao antropomtrica e teste progressivo mximo. Na segunda, foi realizada a prova simulada e, na terceira, foi realizada a competio de XCO. RESULTADOS: a correlao entre a prova simulada e as equaes preditivas do VO2mx de forma absoluta alcanaram relao quase perfeita (r ? 0,9. As correlaes entre a competio real e as estimativas de VO2mx relativizadas massa corporal alcanaram resultados classificados como muito altos (r = 0,7-0,89. As associaes entre a medida direta do VO2mx e a simulao apresentaram uma classificao baixa para valores relativos massa corporal (r = 0,10, IC95% -0,35 a 0,51. Para o desempenho real, a classificao foi moderada (r = 0,48, IC95% 0,009 a 0,78. CONCLUSO: o presente estudo foi o primeiro a demonstrar a validade preditiva das estimativas do VO2mx para o desempenho simulado e real de MTB. Em complemento, confirmou a baixa validade preditiva da medida direta do VO2mx para o mesmo propsito.

  15. BIOMASA DE RACES EN UN BOSQUE TEMPLADO CON Y SIN MANEJO FORESTAL EN HIDALGO, MXICO

    Directory of Open Access Journals (Sweden)

    Numa P. Pavn

    2012-01-01

    Full Text Available Las races son buenos indicadores funcionales del ecosistema ya que constituyen gran parte de la biomasa viva del suelo y ejercen un control sobre los procesos de pedognesis, la produccin de materia orgnica y la dinmica de los nutrientes. En este trabajo se compar la biomasa de races gruesas y finas entre un bosque conservado y un bosque con manejo forestal de corte selectivo. La biomasa promedio de races no difiri significativamente entre sitios (P = 0.185. La biomasa en el bosque con manejo forestal fue de 3.05 Mgha-1 (E. E. = 0.25 y de 3.39 Mgha-1 (E. E. = 0.24 en el bosque conservado. Las races finas ocuparon el mayor porcentaje de la biomasa en ambos tipos de bosque, aunque sus valores no difirieron significativamente entre sitios (P = 0.095. De acuerdo con los resultados, al parecer, el manejo forestal de tipo de corte selectivo mantiene las condiciones ambientales y en particular del suelo, lo que permite contener una biomasa similar a la de un bosque conservado bajo condiciones naturales.

  16. LA BIOMASA DE LOS CULTIVOS EN EL AGROECOSISTEMA. SUS BENEFICIOS AGROECOLGICOS

    Directory of Open Access Journals (Sweden)

    Anirebis Martnez Romero

    2014-01-01

    Full Text Available La biomasa es el resultado de la transformacin de la energa solar en energa qumica. El hombre a travs de la historia la ha utilizado no solo para su alimentacin sino tambin para la alimentacin de sus animales. Los avances de la ciencia promovieron el desarrollo agrario basado en la revolucin verde, la cual solo promueve la produccin de alimentos ya sea de uso humano o animal, marginando la importancia de la biomasa como enriquecedor del recurso suelo al disponerse de los insumos necesarios para sustituir su fertilidad natural. En la actualidad la produccin y conservacin de la biomasa de cualquier cultivo cobra una importancia trascendente; porque ello contribuye, adems, a la proteccin medioambiental a travs de la captura de carbono. El presente trabajo tuvo como objetivo demostrar la importancia que proporciona la biomasa generalmente no alimenticia para los humanos, a fin de emplearla no solo como alimento animal, sino tambin como enriquecedora del recurso natural suelo. Las investigaciones realizadas en Cuba sobre el tema es pobre, aun cuando en la actualidad resulta de gran importancia encontrar variantes que permitan profundizar en la produccin de biomasa en su relacin con el medio ambiente. Finalmente se exponen los resultados preliminares sobre produccin de biomasa a partir de la agrobiodiversidad presente en los escenarios productivos, a la vez que se reflexiona sobre la importancia del tema para futuras investigaciones.

  17. BIOMASA AREA Y FACTORES DE EXPANSIN DE ESPECIES ARBREAS EN BOSQUES DEL SUR DE NUEVO LEN

    Directory of Open Access Journals (Sweden)

    G. Domnguez-Cabrera

    2009-01-01

    Full Text Available El objetivo de este estudio fue la estimacin de biomasa y el clculo de factores de expansin de Pinus pseudostrobus, Pinus teocote, y Quercus spp., en bosques del Sur de Nuevo Len, Mxico. Se derribaron de 8 a 16 rboles por especie, se determin el peso hmedo en campo, se extrajeron muestras para determinar la relacin Peso seco-Peso hmedo (Ps/Ph, con la que se calcul el peso seco total de cada rbol. Se ajustaron modelos de biomasa. La ecuacin que mejor se ajust present la forma y = a(Eb/D +1.3 , donde y es la biomasa area, E exponencial, D dimetro normal, a, b parmetros y 1.3 constante. En todos los casos el coeficiente de determinacin (R2 fue mayor a 0.89 y el error estndar porcentual (Sx% menor a 30.9. Se estim la biomasa por tipo de bosque de acuerdo a los datos de 1,053 rboles obtenidos en las parcelas de muestreo de 400 m2, obtenindose para el bosque de pino 125.333 toneladas de biomasa por hectrea (tBha-1, el de encino-pino 112.593 tBha-1 y el de pino-encino 96.688 tBha-1. Se calcularon factores de expansin de biomasa (Fexp, los valores promedio obtenidos fueron 1,373 para Pinus pseudostrobus, 1,394 para P. teocote y 1,511 para Quercus spp.

  18. New phases in the system LiMnVO4-Mn3(VO4)2

    International Nuclear Information System (INIS)

    The synthesis of orthorhombic Mn3(VO4)2 via a simple solid state route as well as the description of a new tetragonal high temperature phase are reported in this paper. Additionally, the system LiMnVO4-Mn3(VO4)2 (=Mn1.5VO4), described by the formula LixMn1.5-x/2VO4, is investigated in detail, showing that substitution of one Mn2+ in Mn1.5VO4 by two Li+ ions favors the formation of the tetragonal high temperature phase for x?0.22. This substitution is facilitated by the statistical half occupancy of the 4b site by Mn2+ in tetragonal Mn1.5VO4, whereas additional crystallographic sites would have to be occupied in the orthorhombic phase. The inverse substitution of Li by Mn in orthorhombic LiMnVO4 is also shown to be possible in the range 0.72?x?1. For 0.22?x?0.72, there is a large miscibility gap with a two phase mixture of the tetragonal Mn1.5VO4 type and orthorhombic LiMnVO4 type phases. - Graphical Abstract: The unusual coordination of Mn in the form of a stella quadrangula with the surrounding vanadate groups. Highlights: ? First synthesis of orthorhombic Mn3(VO4)2 via a simple solid state route. ? The crystal chemistry of the phases involved is rather complicated and it depends on the amount of Li that is incorporated. ? System LiMnVO4-Mn3(VO4)2 (=Mn1.5VO4), described by the formula LixMn1.5-x/2VO4, is investigated in detail.

  19. Securing VoIP keeping your VoIP network safe

    CERN Document Server

    (Bud) Bates, Regis J Jr

    2015-01-01

    Securing VoIP: Keeping Your VoIP Network Safe will show you how to take the initiative to prevent hackers from recording and exploiting your company's secrets. Drawing upon years of practical experience and using numerous examples and case studies, technology guru Bud Bates discusses the business realities that necessitate VoIP system security and the threats to VoIP over both wire and wireless networks. He also provides essential guidance on how to conduct system security audits and how to integrate your existing IT security plan with your VoIP system and security plans, helping you prevent

  20. Optical Properties of Thermochromic VO2 Nanoparticles

    Science.gov (United States)

    Laaksonen, Katri; Li, S.-Y.; Puisto, S. R.; Niklasson, G. A.; Ala-Nissil, T.; Nieminen, R. M.

    Thermochromic VO2 undergoes metal-insulator transition at temperatures relatively near room temperature. The transition affects its optical properties especially at the near infrared (NIR) wavelengths. Consequently, thin films of VO2 have been proposed for energy-saving applications such as window coatings. At high temperatures, metal VO2 has high reflectivity of NIR light which is absorbed or transmitted at low temperatures. However, if used as nanoparticles instead of thin films, the optical properties of the high-temperature metal VO2 are significantly different. Metal nanoparticles show strong surface plasmon resonance absorption which for VO2 is at NIR wavelengths changing the high reflectivity of NIR light in thin films to absorption in nanoparticles.

  1. Graphene quantum dot sensitized leaf-like InVO4/BiVO4 nanostructure: a novel ternary heterostructured QD-RGO/InVO4/BiVO4 composite with enhanced visible-light photocatalytic activity.

    Science.gov (United States)

    Lin, Xue; Wang, Yushuang; Zheng, Jia; Liu, Chang; Yang, Yang; Che, Guangbo

    2015-11-28

    Leaf-like InVO4/BiVO4 nanostructures with sizes of 2-5 ?m were synthesized by a simple hydrothermal method. Graphene quantum dots (QD-RGO) were then deposited onto the surfaces of the leaf-like InVO4/BiVO4 crystals through a facile deposition-precipitation technique. Under visible light irradiation (? > 420 nm), the QD-RGO/InVO4/BiVO4 photocatalyst degraded rhodamine B (Rh B) efficiently and displayed a much higher photocatalytic activity than pure BiVO4, InVO4, RGO/InVO4, RGO/BiVO4 or an InVO4/BiVO4 hybrid. The InVO4/BiVO4 photocatalyst with 3 wt% of QD-RGO exhibited the highest photocatalytic efficiency. The quenching effects of different scavengers demonstrated that O2?(-) played a major role in Rh B degradation. It was elucidated that the excellent photocatalytic activity of QD-RGO/InVO4/BiVO4 for the degradation of Rh B under visible light (? > 420 nm) can be ascribed to the extended absorption in the visible light region resulting from the QD-RGO loading, the high specific surface area, and the efficient separation of photogenerated electrons and holes through the QD-RGO/InVO4/BiVO4 heterostructure. PMID:26486959

  2. Biomasa acumulada e indicadores de calidad nutritiva en cebadilla chaquea (Bromus auleticus Trinius ex Nees

    Directory of Open Access Journals (Sweden)

    BUSTAMANTE, E.G.R.

    2012-06-01

    Full Text Available Bromus auleticus (cebadilla chaquea es considerada uno de los recursos forrajeros ms promisorios delCono Sur. Presenta variacin entre poblaciones que ha sido determinada para diversos caracteres vegetativos, lo cual podra traducirse en diferencias de produccin y calidad de forraje. El objetivo del presente estudio fue evaluar dos procedencias de cebadilla chaquea (Argentina y Uruguay para biomasa acumulada e indicadores de calidad nutritiva en dos perodos del ao (verano-otoo y otoo-primavera. Se compararon cinco clones uruguayos (U y cinco argentinos (A, dispuestos al azar en surcos distanciados a 1 m entre s, con 10 plantas cada uno. Se determin biomasa acumulada por planta (B y calidad, midiendo Fibra Detergente Neutra (FDN, Protena Bruta (PB y Digestibilidad de la Materia Seca (DMS en dos momentos del ao. En general, la biomasa fue de baja calidad debido al momento en que se realizaron los cortes, lo que limita elalcance de los resultados. Sin embargo, las diferencias observadas entre los clones en este estado de desarrollo podran indicar la existencia de variacin entre genotipos de cebadilla chaquea U y A en biomasa y calidad nutritiva. En biomasa acumulada no se observ efecto significativo de origen. En todas las variablesde calidad evaluadas en verano-otoo, se encontraron diferencias significativas entre orgenes. En otooprimavera, las diferencias entre orgenes fueron significativas para DMS. Los clones U presentaron mayor PB, menor FDN y mayor DMS. Dentro de cada origen, los argentinos presentaron menos diferencias que los uruguayos, tanto en biomasa acumulada como en calidad. Para ninguno de los clones A o U se encontr coincidencia entre mayor biomasa y mayor calidad.

  3. Existencias y tasas de incremento neto de la biomasa y del carbono en bosques primarios y secundarios de Colombia

    OpenAIRE

    Orrego Suaza , Sergio Alonso; Del Valle Arango, Jorge Ignacio

    2002-01-01

    En 33 parcelas permanentes de 1000 m2 (0,1 ha) en bosques primarios y 77 parcelas permanentes de 500 m (0,05 ha) en bosques secundarios, para un rea de muestreo de 7,15 ha, se estimaron las existencias de biomasa y del carbono almacenado en los siguientes compartimientos: biomasa area, necromasa, biomasa subterrnea y suelo. La biomasa area total viva en los bosques primarios promedi 246,542 t/ha, representada 92,42% por rboles y arbustos dicotiledneos, 5,93% en palmas (3,58% la pa...

  4. Biomasa de rotferos de dos embalses con diferentes estados trficos (Antioquia, Colombia y su relacin con algunas variables limnolgicas

    Directory of Open Access Journals (Sweden)

    Silvia L Villabona-Gonzlez

    2014-12-01

    Full Text Available Se evalu la variacin de la biomasa de rotferos en los ejes longitudinal y vertical de la zona ftica de los embalses La Fe y Riogrande II (Antioquia, Colombia, con diferentes estados trficos, durante los periodos de alta y baja precipitacin. Adems, se analiz su relacin con las variables temperatura, oxgeno disuelto, pH, transparencia, nutrientes y con la biomasa fitoplanctnica. La biomasa de rotferos fue dominada por Asplanchna girodi De Geurne 1888, en los dos embalses y fue significativamente mayor en el embalse de menor trofa. Aunque la biomasa de rotferos no mostr un gradiente longitudinal significativo, s present zonacin vertical dentro de la zona ftica, con mayor biomasa en el 10 y 1% de incidencia lumnica. Los patrones de variacin de la biomasa total de rotferos y de las especies dominantes estuvieron determinados principalmente por el ingreso de slidos suspendidos en el embalse de mayor trofa y por la biomasa y la densidad del fitoplancton en el embalse con menos nutrientes. A diferencia de lo esperado, la biomasa de los rotferos no fue favorecida por condiciones de mayor estado trfico, ya que el factor preponderante sobre la expresin de biomasa fue la calidad de los recursos alimenticios en cada embalse.

  5. Selective Synthesis of Mesoporous and Nanorod CeVO4 without Template

    International Nuclear Information System (INIS)

    A simple and efficient method has been established for the selective synthesis of mesoporous and nanorod CeVO4 with different precursors by sonochemical method. CeVO4 nanorod can be simply synthesized by ultrasound irradiation of Ce(NO3)3 and NH4VO3 in aqueous solution without any surfactant or template. While mesoporous CeVO4 with high specific surface area can be prepared with Ce(NO3)3, V2O5 and NaOH in the same way. Mesoporous CeVO4 has a specific surface area of 122 m2 g-1 and an average pore size of 5.2 nm; CeVO4 nanorods have a diameter of about 5 nm, and a length of 100-150 nm. The ultrasound irradiation and ammonia in the reactive solution are two key factors in the formation of such rod-like products. X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric (TG) and differential thermal analyses (DTA), UV/vis absorption spectroscopy and Brunauer-Emmett-Teller (BET) were applied for characterization of the as-prepared products

  6. Hydrothermal Synthesis and Photocatalytic Properties of Cu-doped BiVO4 Microsheets

    Directory of Open Access Journals (Sweden)

    LIU Guo-Cong, JING Zhen, ZHANG Xi-Bing, LI Xian-Feng, LIU Hong

    2013-03-01

    Full Text Available Using Bi(NO335H2O, NaVO3 and Cu(NO323H2O as raw materials, Cu-doped BiVO4 microsheets were synthesized by ultrasonic-hydrothermal process with cetyltrimethyl ammonium bromide (CTAB as template. The as-prepared samples were investigated by XRD, XPS, SEM, HRTEM, UV-Vis and BET tests. The results reveal that uniform and well crystallized Cu/BiVO4 microsheets in monoclinic crystal structure, with length of 1.02.0 ?m, width of 0.52.0 ?m and thickness of 200300 nm, could be obtained via an ultrasonic-hydrothermal route assisted by 2.0 g CTAB. Compared with BiVO4 particles, Cu/BiVO4 nanosheets show a little red shift in the absorption band, resulting in a narrowed band gap (<2.4 eV. For 5.0wt% Cu/ BiVO4 microsheet, its photodegradation rate constant K is5.89 102 /min and the best photocatalytic activity is found with a 100% degradation of methylene blue (MB with 10 mg/L concentration under visible-light irradiation for 60 min.

  7. Security in VoIP

    Directory of Open Access Journals (Sweden)

    Floriana GEREA

    2012-04-01

    Full Text Available VoIP relies on packet switching, similar to the way that e-mails are sent over the Internet. The technology breaks down a voice call into bite-size information packets. Instead of keeping the switch open all the time, the information is sent and received as needed, allowing excess line capacity to be used to carry other data. When the voice data arrives at its destination, it's reassembled into a voice call. As voice over IP services grow in popularity, the potential for viruses, worms and other security threats aimed at the technology also will grow. The current paper's purpose is presenting several security solutions and applying them to integrated systems at an economical and social level.

  8. Antifungalna aktivnost propolisa u ?etiri vrste vo?nih sokova

    OpenAIRE

    Koc, Ayse Nedret; Silici, Sibel; Mutlu-Sariguzel, Fatma; Sagdic, Osman

    2007-01-01

    Vo?ni sokovi i negazirana pi?a podloni su kvarenju u prisutnosti kvasaca, plijesni i bakterija. Svrha je ovog istraivanja ispitati antifungalni u?inak etanolnog ekstrakta turskog propolisa (ETTP) u nepasteriziranom soku jabuke, naran?e, bijeloga gro?a i mandarine na 6 razli?itih sojeva kvasca izoliranih iz pokvarenih sokova. Izolirani su sojevi kvasca Candida famata, C. glabrata, C. kefyr, C. pelliculosa, C. parapsilosis i Pichia omeri. Minimalna inhibicijska koncentracija (MIC) odre?ena j...

  9. Fuzzing dans la sphre VoIP

    OpenAIRE

    Abdelnur, Humberto; Festor, Olivier; State, Radu

    2008-01-01

    La voix sur IP (VoIP) s'impose aujourd'hui comme l'une des technologies clefs de l'Internet actuel et futur. Dans cet article, nous partageons l'exprience pratique acquise ces deux dernires annes par notre quipe de recherche sur l'automatisation des processus de dcouverte de vulnrabilits dans le monde VoIP. Nous dressons un portrait relativement sombre de la scurit actuelle de la sphre VoIP en prsentant les vulnrabilits les plus dangereuses capables d'aboutir la compromission d...

  10. Comprehensive Comparison of VoIP SIP Protocol Problems and Cisco VoIP System

    Directory of Open Access Journals (Sweden)

    TALAL AL-KHAROBI

    2012-08-01

    Full Text Available Voice over IP (VoIP, use of the packet switched internet for telephony, has improved substantially in the past few years. On the other hand, VoIP has many challenges that do not exist in the public switched telephone network (PSTN, a circuit switched system. VoIP is an application running on the internet, and therefore inherits the internets security issues. It is important to realise that VoIP is a relatively young technology, and with any new technology, security typically improves with maturity. This paper provides a comprehensive comparison of a VoIP SIP protocol and CISCO VoIP system. The comparison involves the investigation of the vulnerabilities that target both systems and how secure each system is. With this comparison we present our conclusion on which system is more secure.

  11. Comprehensive Comparison of VoIP SIP Protocol Problems and Cisco VoIP System

    OpenAIRE

    TALAL AL-KHAROBI; Mohmmed Abduallah Al-Mehdhar

    2012-01-01

    Voice over IP (VoIP), use of the packet switched internet for telephony, has improved substantially in the past few years. On the other hand, VoIP has many challenges that do not exist in the public switched telephone network (PSTN), a circuit switched system. VoIP is an application running on the internet, and therefore inherits the internets security issues. It is important to realise that VoIP is a relatively young technology, and with any new technology, security typically improves with ...

  12. A Comprehensive Secure VoIP Solution

    Directory of Open Access Journals (Sweden)

    Ashraf D. Elbayoumy

    2007-09-01

    Full Text Available VoIP represents the future of digital voice communications and many carriers are preparing for the VoIP revolution. However, a number of outstanding issues need to be settled. The most important are security, compression, packet size optimization, quality of service and performance in heterogeneous networks. We have addressed all of these issues [2, 3, 4, 5] and here we summarize our key findings in each of these areas.

  13. A Comprehensive Secure VoIP Solution

    OpenAIRE

    Ashraf D. Elbayoumy; Simon Shepherd

    2007-01-01

    VoIP represents the future of digital voice communications and many carriers are preparing for the VoIP revolution. However, a number of outstanding issues need to be settled. The most important are security, compression, packet size optimization, quality of service and performance in heterogeneous networks. We have addressed all of these issues [2, 3, 4, 5] and here we summarize our key findings in each of these areas.

  14. Performance Evaluation for VoIP on Campus

    Directory of Open Access Journals (Sweden)

    Rendy Munadi

    2013-09-01

    Full Text Available The VoIP Campus implementation is to make the existing VoIP technology become more beneficial for campus stake holder. This VoIP on Campus (VoC technology make use of a web server, facilitating users to carry out VoIP registration, get and changing account, and also to see others who have register and active in this VoIP network. Basically, this VoC infrastructure uses asterisk as VoIP server and playVoIP as web server interface, those programs included in a server computer. Furthermore, the server interconnected with several servers, such as, PBX, SMS gateway, ENUM server, softphone and smartphone. At this moment, VoC network serve locally, but next time it will be developed so that it could be served in public network, and further VoC network could be connected to VoIP Rakyat, the biggest VoIP network in Indonesia. In this research, VoC network have been tested for several QoS parameters, such as throughput, delay, jitter, packet loss, and MOS. Average value for each parameter, are : 27 kbps throughput, 20.08 ms delay, 3.54 ms jitter, 0.08% packet loss, and 3.3 MOS. Those results indicates that VoC network have a good performance.

  15. Scalable architecture for VoIP privacy

    Science.gov (United States)

    Medvinsky, Alexander

    2001-07-01

    An access network for Voice over IP (VoIP) clients (e.g. DOCSIS-based HFC network) often provides a privacy service. However, such a privacy service is limited only to that access network. When VoIP packets are carried over an open IP network or over a network with some connections to the Internet, it is desirable to provide an end-to-end privacy service where each VoIP packet is encrypted at the source and decrypted at the terminating endpoint. Clearly, public key encryption cannot be applied to each voice packet; the performance would be unacceptable regardless of the choice of a public key algorithm. The only alternative is for the two VoIP endpoints to negotiate a shared symmetric key. Since VoIP connections are established only for duration of a phone call, the end-to-end key negotiation needs to occur during each call setup. And it should not noticeably delay the call setup phase. In order to provide end-to-end privacy, it is not sufficient to encrypt all messages between the two endpoints. It is important that the two endpoints authenticate each other - validate each other's identity. Without authentication an adversary might trick two VoIP clients to negotiate keys with her and then sit in the middle of their conversation and record each VoIP packet, before forwarding it to the intended destination. However, direct authentication of the two VoIP endpoints is not always possible in telephony networks - in particular when caller ID blocking services are enabled. To support such anonymity services, it may be sufficient to authenticate not the identity of the caller but the fact that it is a valid subscriber and that all subsequent signaling and voice traffic will be coming from the same source. The PacketCable specifications provide an example of a VoIP architecture with end-to-end privacy that meets the above stated criteria. This paper describes the PacketCable end-to-end privacy approach and suggests additional mechanisms that may be used to further strengthen VoIP privacy under the PacketCable architecture.

  16. Estudio terico de la combustin de pellets de biomasa procedente de la caa de azcar

    Directory of Open Access Journals (Sweden)

    David Verdecia Torres

    2012-01-01

    Full Text Available En el siguiente trabajo se examina la cintica qumica de la combustin de pellets de biomasa caera, se obtiene el tiempo de combustin en funcin de la etapa controlante del proceso de combustin segn el modelo de ncleo sin reaccionar, adems se realiza un diseo de experimento para determinar los modelos matemticos tericos para modelar el proceso de combustin.

  17. Almacenamiento de carbono en la biomasa area de una plantacin joven de pinus greggii Engelm.

    Directory of Open Access Journals (Sweden)

    Felcitas Clemencia Pacheco Escalona

    2007-01-01

    Full Text Available Con el objetivo de evaluar el potencial de Pinus greggii Engelm. para almacenar carbono en la biomasa area, se estim la biomasa total area en una muestra de 20 rboles, los cuales se separaron en tallo, ramas y follaje. El estudio se llev a cabo en una plantacin de seis aos de edad establecida en Cuaunepantla, Acaxochitln, Estado de Hidalgo, Mxico. La biomasa seca area promedio fue de 8.0 kg por rbol, de la cual 4.1 kg (51 % se ubic en tallo, 1.9 kg (24 % en ramas y 2.0 kg (25 % en follaje. La productividad primaria neta fue estimada en 5.8 t ha-1 ao-1, para una densidad de 4425 rboles/ha. La concentracin de carbono en tejido vegetal fue de 51 %. Una ecuacin matemtica sencilla (y = 147x + 3288x2 para estimar la biomasa de carbono a partir de la variable combinada de dimetro y altura (D2h explic 89 % de la variacin. Estos resultados muestran que el potencial de almacenamiento de carbono en una plantacin de seis aos de P. greggii Engelm. es relativamente alto, con 17.9 t ha-1, que representa una masa de dixido de carbono equivalente de 65.8 t CO2 ha-1.

  18. Biomasa y densidad de dos especies de pastos marinos en el sur de Quintana Roo, Mxico

    Directory of Open Access Journals (Sweden)

    Martha Anglica Gutirrez-Aguirre

    2000-06-01

    Full Text Available La biomasa y productividad de una comunidad de pastos marinos es til para determinar el estado ecolgico de la costa. Se compar la biomasa foliar y la densidad de vainas en praderas de Thalassia testudinum Banks & Sol. ex K. D. Koenig, en dos ambientes de la costa del Caribe mexicano (N= 6 cuadrantes/sitio en Noviembre de 1998. Los valores de vainas y biomasa foliar fueron ms bajos en la pradera asociada al manglar, que en la pradera establecida en una laguna arrecifal. Esto probablemente se deba a que las hojas del manglar tuvieron porcentaje ms alto de epfitas. Por otro lado, T. testudinum tuvo mayor biomasa que Syringodium filiforme Ktz en la laguna arrecifal.The biomass and productivity of a seagrass community are useful for determining the ecological status of the coast. Leaf biomass and shoot density in beds of Thalassia testudinum Banks & Sol. ex K. D. Koenig, were compared for two environments in the Mexican Caribbean coast (N= 6 quadrants/site in November 1998. Shoot and leaf biomass values were lower in the mangrove-associated meadow than in the reef lagoon meadow. This could be related to the higher percentage of epiphytes on mangrove leaves. In addition, T. testudinum had more biomass than Syringodium filiforme Ktz in the reef lagoon.

  19. Lattice relaxation and ferromagnetic character of (LaVO3)m/SrVO3superlattices

    Science.gov (United States)

    Schuster, Cosima; Lders, Ulrike; Frsard, Raymond; Schwingenschlgl, Udo

    2013-08-01

    The experimental observation that vanadate superlattices (LaVO3)m/SrVO3 show ferromagnetism up to room temperature (Lders U. et al., Phys. Rev. B, 80 (2009) 241102(R)) is investigated by means of density functional theory, and the band structure for m = 5 and 6 is calculated. A buckling of the interface VO2 layers is found in both cases, but subtle differences in bond length lead to very different properties for even and odd values of m: in the even case, the two interface VO2 layers effectively decouple from the adjacent LaO layers due to a strong bond length enhancement. This results into a local inversion of the orbital occupancy and to the confinement of the charge carriers. In the odd case, the amplitude of the bond length variation is smaller, so that the charge carriers spill into the deeper-lying VO2 layers, and spin-polarised interfaces are obtained.

  20. Biomasa de Cornops aquaticum (Orthoptera: Acrididae en humedales del nordeste de Argentina

    Directory of Open Access Journals (Sweden)

    Luciana Irene Gallardo

    2015-03-01

    Full Text Available La estimacin de la biomasa en las poblaciones de insectos, es un factor clave para cuantificar los recursos disponibles y los flujos de energa en las redes trficas de los ecosistemas. Cornops aquaticum es un herbvoro comn en las plantas de Eichhornia en los humedales del nordeste de Argentina. Nuestro objetivo fue analizar la variacin de su biomasa en relacin a las distintas categoras de edades de la poblacin de este acridio, en dos plantas husped: Eichhornia azurea y Eichhornia crassipes. Para ello, se realizaron muestreos estndar de las poblaciones de C. aquaticum con una red entomolgica de 70cm de dimetro, en dos humedales con E. azurea y E. crassipes en las provincias de Corrientes y Chaco; adems, se obtuvo el peso seco de los individuos (de manera directa e indirecta y, se propuso un modelo de regresin para estimar la biomasa de C. aquaticum de manera indirecta a partir de una medida de dimensin lineal (longitud del fmur posterior. Un total de 2 307 individuos fueron recolectados y separados en distintas categoras de edades; se obtuvo su abundancia y distintas medidas de dimensin lineal. El modelo propuesto fue lnPS=lna+b*lnH (donde PS=peso seco, a y b son constantes y H=longitud del fmur posterior (R=0.97. Las variaciones en la biomasa de las poblaciones de C. aquaticum se debieron a la abundancia relativa de cada categora de edad y al peso seco individual de estos acridios. No hubo diferencias significativas entre la biomasa de las poblaciones de C. aquaticum obtenida por los mtodos directo e indirecto en las praderas flotantes de E. azurea y E. crassipes. Este modelo facilita el clculo de la biomasa individual y poblacional de C. aquaticum y acelera el procesamiento de un gran nmero de muestras. Finalmente, los valores altos de biomasa poblacional e individual de las categoras de edades (especialmente en adultos enfatizan la importancia de C. aquaticum como consumidor y como recurso para los depredadores en las redes alimenticias de las praderas flotantes de Eichhornia.

  1. Biorefinery Technologies for Biomass Conversion Into Chemicals and Fuels Towards Zero Emissions (Review) / Nulles Emisiju Princips Biomasas Konversijas Tehnolo?ij?s Aizst?jot Fosilos Resursus (P?rskata Raksts)

    Science.gov (United States)

    Gravitis, J.; Abolins, J.

    2013-10-01

    Exhausting of world resources, increasing pollution, and climate change are compelling the shift of the world economy from continuous growth to a kind of economy based on integration of technologies into zero emissions production systems. Transition from non-renewable fossil resources to renewable resources provided by solar radiation and the current processes in biosphere is seen in the bio-refinery approach - replacing crude oil refineries by biomass refineries. Biotechnology and nano-technologies are getting accepted as important players along with conventional biomass refinery technologies. Systems design is a significant element in the integration of bio-refinery technologies in clusters. A number of case-studies, steam explosion auto-hydrolysis (SEA) in particular, are reviewed to demonstrate conversion of biomass into value-added chemicals and fuels. Analysis of energy flows is made as part of modelling the SEA processes, the eMergy (energy memory) approach and sustainability indices being applied to assess environmental impacts. Resursu izs?kums, vides pies?r?ojums un glob?la m?roga klimatisk?s izmai?as ir civiliz?cijas izdz?voanai b?tiski faktori, kas virza pasaules ekonomikas p?rmai?as, atsakoties no nep?rtrauktas izaugsmes idejas par labu t?dai ekonomikai, kas balst?s uz atjaunojoamies resursiem un da?du tehnolo?iju integr?cijemisiju principam atbilsto?s raoanas sist?m?s. Saules radi?cijas ierosin?tajos plan?tas biosf?r? notiekoajos procesos rad?to organisko vielu p?rstr?des kompleksi, kas oper? iev?rojot sabalans?tu nulles emisiju principu, tiek uzl?koti k? t?s ekonomisk?s (raoanas) strukt?ras, kur?m j?nodroina p?reja uz atjaunojoos resursu izmantoanu, aizst?jot eso?s fosilo resursu (naftas, og?u) p?rstr?des r?pn?cas. L?dz?s jau apg?taj?m biomasas rafin?anas tehnolo?ij?m svar?ga un pieaugoa loma ekonomisk?s sist?mas resursu b?zes nomai?? ir bio- un nanotehnolo?ij?m, bet raoanas sist?mu projekt?anai - biomasas konversijas tehnolo?iju klasteriz?cij?. Apl?kojot virkni konkr?tu tehnolo?isko risin?jumu, TSA - biomasas autohidrol?zi tvaika spr?dzien? tai skait?, iztirz?tas ar biomasas konversiju, izmantoanu un augstas pievienot?s v?rt?bas produktiem - ??miskiem savienojumiem un degviel?m, saist?t?s ekololo?isk?s un energoefektivit?tes probl?mas. Uzsverot biomasas TSA pirmapstr?des univers?lo noz?mi da?do tehnolo?isko kompleksu strukt?r?, apl?kota TSA ietekme uz vidi, demonstr?jot eMer?ijas (ener??tisk?s atmi?as) pieeju un ilgtsp?jas" indeksu izmantoanu. Lai gan pie sasniegt? tehnolo?isk?s att?st?bas l?me?a un patreiz?jiem fosilo ener?ijas nes?ju pat?ri?a tempiem nav iesp?jams tos piln?b? aizst?t ar bioener?iju, bioener?ijas sektora tehnolo?iju pilnveidoana ir svar?ga ar? bioresursu racion?las izmantoanas un citos aspektos. Latvijas ener??tisk?s neatkar?bas kontekst? b?tiska noz?me ir tradicion?lo bioener?ijas resursu izmantoanas efektivit?tes celanai un inovat?vo bioener?ijas tehnolo?iju valstiskam atbalstam.u nulles

  2. The Vanadium(V) Oxoazides [VO(N3)3], [(bipy)VO(N3)3], and [VO(N3)5](2-).

    Science.gov (United States)

    Haiges, Ralf; Vasiliu, Monica; Dixon, David A; Christe, Karl O

    2015-07-27

    Vanadium(V) oxoazide [VO(N3)3] was prepared through a fluoride-azide exchange reaction between [VOF3] and Me3SiN3 in acetonitrile solution. When the highly impact- and friction-sensitive compound [VO(N3)3] was reacted with 2,2?-bipyridine, the adduct [(bipy)VO(N3)3] was isolated. The reaction of [VO(N3)3] with [PPh4]N3 resulted in the formation and isolation of the salt [PPh4]2[VO(N3)5]. The adduct [(bipy)VO(N3)3] and the salt [PPh4]23[VO(N3)5] were characterized by vibrational spectroscopy and single-crystal X-ray structure determination, making these compounds the first structurally characterized vanadium(V) azides. PMID:26072899

  3. Understanding VoIP from Backbone Measurements

    OpenAIRE

    Birke, Robert Rene' Maria; Mellia, Marco; Petracca, Michele

    2007-01-01

    VoIP has widely been addressed as the technology that will change the Telecommunication model opening the path for convergence. Still today this revolution is far from being complete, since the majority of telephone calls are originated by circuit-oriented networks. In this paper for the first time to the best of our knowledge, we present a large dataset of measurements collected from the FastWeb backbone, which is one of the first worldwide Telecom operator to offer VoIP and high-speed data ...

  4. Euro-VO-Coordination of virtual observatory activities in Europe

    Science.gov (United States)

    Genova, Franoise; Allen, Mark G.; Arviset, Christophe; Lawrence, Andy; Pasian, Fabio; Solano, Enrique; Wambsganss, Joachim

    2015-06-01

    The European Virtual Observatory Euro-VO has been coordinating European VO activities through a series of projects co-funded by the European Commission over the last 15 years. The bulk of VO work in Europe is ensured by the national VO initiatives and those of intergovernmental agencies. VO activities at the European level coordinate the work in support of the three "pillars" of the Virtual Observatory: support to the scientific community, take-up by the data providers, and technological activities. Several Euro-VO projects have also provided direct support to selected developments and prototyping. This paper explains the methodology used by Euro-VO over the years. It summarises the activities which were performed and their evolutions at different stages of the development of the VO, explains the Euro-VO role with respect to the international and national levels of VO activities, details the lessons learnt for best practices for the coordination of the VO building blocks, and the liaison with other European initiatives, documenting the added-value of European coordination. Finally, the current status and next steps of Euro-VO are briefly addressed.

  5. Electron paramagnetic resonance and optical absorption study of VO2+-doped sodium zinc sulfate tetrahydrate single crystals

    International Nuclear Information System (INIS)

    Single-crystal electron paramagnetic resonance (EPR) studies of VO2+ doped in sodium zinc sulfate tetrahydrate (Na2Zn(SO4)2·4H2O) have been carried out at room temperature. The results show the presence of three magnetically inequivalent VO2+ sites with different populations. The VO2+ impurity ions take up substitutional positions in the host lattice replacing Zn2+ ions. The angular variation of EPR spectra in three mutually orthogonal planes, bc, a*c and ba*, are used to determine the spin-Hamiltonian parameters. The optical absorption spectrum of VO2+ ions doped in the crystal lattice is also recorded at room temperature in the wavelength range 325-1100 nm. This is utilized to study the energy level structure of the VO2+ ion. By correlating the EPR and optical data, various molecular orbital coefficients of the VO2+ ion with its ligands are evaluated and the nature of bonding in the crystal is discussed.

  6. Recuperacin de la biomasa mediante la sucesin secundaria, Cordillera Central de los Andes, Colombia

    Directory of Open Access Journals (Sweden)

    Jorge Ignacio del Valle

    2011-09-01

    Full Text Available En bosques secundarios premontanos tropicales es escasa la informacin sobre el tiempo requerido para recuperar la biomasa area y subterrnea de los primarios. Por lo tanto, establecimos 33 parcelas de 0.1ha entre 550 y 1 700m en bosques secundarios que cubran estadios serales de 3 a 36 aos y estimamos la biomasa de las plantas y de las races gruesas con ecuaciones locales. As como la biomasa de las pasturas y barbechos por cosecha de 54 y 18 parcelas, respectivamente. Tambin se calcul la edad de las parcelas con informantes locales, sensores remotos, C14 y anillos de crecimiento. En cada parcela medimos la biomasa area viva por hectrea (Bav y la de las races gruesas por hectrea (Brg. Modelamos la Bav y Brg en funcin de la edad mediante la ecuacin de von Bertalanfy con asntotas de 247t/ha (Bav y 66t/ha (Brg resultantes de la medicin de 33 parcelas de 0.1ha en los bosques primarios. Con la razn Brg/Bav=f(t estimamos 87 aos para que los bosques secundarios recuperen la Bav existente en los primarios y 217 aos para recuperar la Brg. La tasa mxima de crecimiento instantneo de la Bav fue 6.95t/ha/ao a los 10 aos y la tasa media mxima de crecimiento 6.26t/ha/ao a los 17 aos. La media ponderada de la tasa de crecimiento absoluto de la Bav alcanz 4.57t/ha/ao y la relativa 10% anual. La razn Brg/Bav inicialmente aumenta muy aceleradamente hasta 4-5 aos (25%, luego disminuye hasta 25 aos (18% para luego incrementar hasta 26.7

  7. Estudio de la naturaleza qumica de biocrudos obtenidos mediante licuefaccin hidrotrmica de biomasa lignocelulsica

    OpenAIRE

    Castro Vega, Alejandro Amadeus

    2011-01-01

    El agotamiento de los combustibles de origen fsil as como los problemas ambientales asociados con su uso promueve la investigacin y desarrollo de procesos desvinculados de este tipo de energa y recursos para proveer sustentabilidad al desarrollo humano. La conversin hidrotrmica de biomasa es una tecnologa promisoria para obtener combustibles e insumos qumicos, utilizando agua y temperaturas cercanas al punto crtico, que en tales condiciones acta como solvente, catalizador y reactant...

  8. Modelacin de la gasificacin de biomasa en un reactor de lecho fijo

    OpenAIRE

    Garca Patio, Harold Jhair

    2011-01-01

    Se realiza la modelacin matemtica de un reactor de lecho fijo de calentamiento indirecto que tiene en cuenta los procesos de transferencia de calor y de masa y las reacciones qumicas que ocurren durante la transformacin termoqumica de biomasa a travs de los procesos de pirlisis y gasificacin. Mediante este modelo se puede predecir la composicin de los gases obtenidos y la distribucin de temperaturas en el interior del reactor, en cualquier instante de tiempo. El modelo se desarrolla...

  9. Gallinaza: un residual avcola como fuente alternativa de nutrientes para produccin de biomasa microalgal

    OpenAIRE

    Rosales Loaiza Nestor Luis; Bermdez Jos Luis; Moronta Reyna; Morales Ever Daro

    2008-01-01

    La gallinaza puede ser usada como una fuente alternativa de nutrientes para el cultivo de microalgas, proveyendo de biomasa microalgal utilizable como producto final. El objetivo de este trabajo fue evaluar el efecto de la fraccin soluble de gallinaza (FSG) a tres diferentes concentraciones (6, 18 y 36%) sobre el crecimiento, la produccin de pigmentos y protenas de la microalga marina Chroomonas sp. y de la microalga de agua dulce Chlorella sorokiniana. La FSG no biodegradada mostr un efe...

  10. Efecto de nutrientes sobre la produccin de biomasa del hongo medicinal ganoderma lucidum

    OpenAIRE

    Ana Mara Torres Lpez; Juan Carlos Quintero Daz; Luca Atehortua Garcs

    2011-01-01

    Effect of nutrients in the biomass production of the medicinal mushroom Ganoderma lucidumTtulo corto: Efecto de nutrientes sobre la produccin de G. lucidumResumen El hongo Ganoderma lucidum, en los constituyentes de su biomasa, tiene compuestos con propiedades benficas para la salud; es por esto que el conocimiento de las condiciones nutricionales adecuadas para su crecimiento permitir su produccin industrial y a bajo costo. En este trabajo se evalu a nivel de matraz el efecto de la r...

  11. Densidad y biomasa de macroinvertebrados acuticos derivantes en una quebrada tropical de montaa (bogot, colombia)

    OpenAIRE

    RODRGUEZ-BARRIOS JAVIER; OSPINA-TORRES RODULFO; GUTIRREZ JUAN DAVID; OVALLE HERNANDO

    2013-01-01

    Se estim la variacin en la densidad de deriva de macroinvertebrados acuticos y suaporte de materia orgnica en trminos de biomasa de diferentes estados inmadurose imagos, en un tramo de una quebrada tropical de montaa ubicada en los cerrosorientales de Bogot Colombia y durante eventos de altas y bajas precipitaciones.Se colect un total de 96 taxones de los cuales el ms abundante fue Simulium con194 individuos (abundancia total). La densidad de deriva al igual que el aporte debiomasa...

  12. Visible light driven photocatalysis and antibacterial activity of AgVO3 and Ag/AgVO3 nanowires

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: Ag/AgVO3 and pure AgVO3 nanowires synthesized by sonochemical process. Characterization done using XRD, SEM, TEM, EDX and BET analysis. Visible light degradation of RhB by Ag/AgVO3 within 45 min. Antibacterial activity of Ag/AgVO3 demonstrated. - Abstract: Ag/AgVO3 nanowires and AgVO3 nanorods were synthesized in aqueous media via a facile sonochemical route. The as-synthesized products were characterized by X-ray diffraction, BrunauerEmmettTeller surface area analysis, scanning electron microscopy together with an energy dispersion X-ray spectrum analysis, transmission electron microscopy and UVvis diffuse reflectance spectroscopy. The results revealed that inert atmosphere promotes the formation of Ag/AgVO3 nanowires. The photocatalytic studies revealed that the Ag/AgVO3 nanowires exhibited complete photocatalytic degradation of Rhodamine B within 45 min under visible light irradiation. The antibacterial activity of Ag/AgVO3 nanowires was tested against Escherechia coli and Bacillus subtilis. The minimum growth inhibitory concentration value was found to be 50 and 10 folds lower than for the antibiotic ciprofloxacin for E. coli and B. subtilis, respectively. The antibacterial properties of the ?-AgVO3 nanorods prove that in case of the Ag dispersed Ag/AgVO3 nanowires, the enhanced antibacterial action is also due to contribution from the AgVO3 support

  13. PRODUCCIÓN DE BIOMASA DE Artemia franciscana Kellogg 1906 UTILIZANDO DIFERENTES DIETAS

    Directory of Open Access Journals (Sweden)

    Rosario Cisneros

    2009-01-01

    Full Text Available Se realizó el cultivo semiintensivo de Artemia franciscana, cepa Perú, utilizando diferentes dietas en base a microalgas e insumos alimenticios que forman parte de algunos ingredientes que se utilizan para preparar alimento formulado de peces y crustáceos, con el fin de determinar la factibilidad del uso de estos para la obtención de biomasa de adultos. El estudio se ejecutó en base a un diseño experimental completamente aleatorio con 7 tratamientos y 3 réplicas cada uno, aplicándose a los datos obtenidos un Análisis de Varianza de una vía (ANOVA y la prueba de Tukey para establecer diferencias significativas entre los tratamientos. Los resultados del análisis próximal de las dietas, mostraron que la harina de soya presentó la cantidad de proteínas requerida por A. franciscana durante su crecimiento (34.33 %, igualmente con esta dieta se obtuvo la mejor tasa de crecimiento (0.19, biomasa más alta (113.33 g y el mejor Factor de Conversión Alimenticia (1.4. Así mismo la biomasa de A. franciscana producida con harina de soya, presentó un nivel de proteínas adecuado para la maduración de reproductores de crustáceos (53.38 %.

  14. PRODUCCIN DE BIOMASA DE Artemia franciscana Kellogg 1906 UTILIZANDO DIFERENTES DIETAS

    Directory of Open Access Journals (Sweden)

    Rosario Cisneros

    2009-01-01

    Full Text Available Se realiz el cultivo semiintensivo de Artemia franciscana, cepa Per, utilizando diferentes dietas en base a microalgas e insumos alimenticios que forman parte de algunos ingredientes que se utilizan para preparar alimento formulado de peces y crustceos, con el fin de determinar la factibilidad del uso de estos para la obtencin de biomasa de adultos. El estudio se ejecut en base a un diseo experimental completamente aleatorio con 7 tratamientos y 3 rplicas cada uno, aplicndose a los datos obtenidos un Anlisis de Varianza de una va (ANOVA y la prueba de Tukey para establecer diferencias significativas entre los tratamientos. Los resultados del anlisis prximal de las dietas, mostraron que la harina de soya present la cantidad de protenas requerida por A. franciscana durante su crecimiento (34.33 %, igualmente con esta dieta se obtuvo la mejor tasa de crecimiento (0.19, biomasa ms alta (113.33 g y el mejor Factor de Conversin Alimenticia (1.4. As mismo la biomasa de A. franciscana producida con harina de soya, present un nivel de protenas adecuado para la maduracin de reproductores de crustceos (53.38 %.

  15. Service Improvements for a VoIP Provider

    OpenAIRE

    LI, ZHANG

    2009-01-01

    This thesis project is on helping a Voice over Internet Protocol (VoIP) service provider by improving server side of Opticall AB's Dial over Data solution. Nowadays, VoIP is becoming more and more popular. People use VoIP to call their family and friends every day. It is cheap, especially when users are abroad, because that they do need to pay any roaming fee. Many companies also like their employees to use VoIP, not only because the cost of calling is cheap, but using VoIP means that the com...

  16. A low cost preparation of VO2 thin films with improved thermochromic properties from a solution-based process

    International Nuclear Information System (INIS)

    This paper describes a solution-based route to synthesize vanadium dioxide (VO2) thermochromic thin films on glass substrate by spin-coating technology followed by nitrogen-annealing with vanadium pentoxide (V2O5) and oxalic acid (H2C2O4) as source material, which is fairly economical and practical. Surface morphologies indicate that the films obtained by this method are homogeneous and particulate, irregular prisms emerge as the annealing temperatures increase. X-ray diffractions show that films annealed at relatively low temperature are pure monoclinic phase with a preferred orientation of (011). NaV4O7 and NaV6O15 form along with raising the heating temperatures. VO2 films obtained exhibit excellent visible transparency and switching property at near-infrared wavelengths across the metalsemiconductor transition. Transmittance change at ? = 2000 nm of VO2 thin film annealed at 450 C attains as high as 41.5% and its solar modulation efficiency reaches up to 8.8%. The W-doped VO2 film at a doping level of 1 at.% exhibits a thermochromic switch at 37 C with a narrow hysteresis, which will greatly favor the practical application of VO2-based smart windows. - Highlights: ? Vanadium dioxide thermochromic film was prepared via a solution-based deposition. ? Tungsten doping reduced the phase transition temperature to 37 C. ? Tungsten doping narrowed the transmittance hysteresis loop. ? Our results will propel the application to vanadium dioxide-based smart windows

  17. Euro-VO - Coordination of Virtual Observatory activities in Europe

    CERN Document Server

    Genova, Francoise; Arviset, Christophe; Lawrence, Andy; Pasian, Fabio; Solano, Enrique; Wambsganss, Joachim

    2015-01-01

    The European Virtual Observatory Euro-VO has been coordinating European VO activities through a series of projects co-funded by the European Commission over the last 15 years. The bulk of VO work in Europe is ensured by the national VO initiatives and those of intergovernmental agencies. VO activities at the European level coordinate the work in support of the three "pillars" of the Virtual Observatory: support to the scientific community, take-up by the data providers, and technological activities. Several Euro-VO projects have also provided direct support to selected developments and prototyping. This paper explains the methodology used by Euro-VO over the years. It summarizes the activities which were performed and their evolutions at different stages of the development of the VO, explains the Euro-VO role with respect to the international and national levels of VO activities, details the lessons learnt for best practices for the coordination of the VO building blocks, and the liaison with other European i...

  18. Epitaxial stabilization and phase instability of VO2 polymorphs.

    Science.gov (United States)

    Lee, Shinbuhm; Ivanov, Ilia N; Keum, Jong K; Lee, Ho Nyung

    2016-01-01

    The VO2 polymorphs, i.e., VO2(A), VO2(B), VO2(M1) and VO2(R), have a wide spectrum of functionalities useful for many potential applications in information and energy technologies. However, synthesis of phase pure materials, especially in thin film forms, has been a challenging task due to the fact that the VO2 polymorphs are closely related to each other in a thermodynamic framework. Here, we report epitaxial stabilization of the VO2 polymorphs to synthesize high quality single crystalline thin films and study the phase stability of these metastable materials. We selectively deposit all the phases on various perovskite substrates with different crystallographic orientations. By investigating the phase instability, phonon modes and transport behaviours, not only do we find distinctively contrasting physical properties of the VO2 polymorphs, but that the polymorphs can be on the verge of phase transitions when heated as low as ~400?C. Our successful epitaxy of both VO2(A) and VO2(B) phases, which are rarely studied due to the lack of phase pure materials, will open the door to the fundamental studies of VO2 polymorphs for potential applications in advanced electronic and energy devices. PMID:26787259

  19. Epitaxial stabilization and phase instability of VO2 polymorphs

    Science.gov (United States)

    Lee, Shinbuhm; Ivanov, Ilia N.; Keum, Jong K.; Lee, Ho Nyung

    2016-01-01

    The VO2 polymorphs, i.e., VO2(A), VO2(B), VO2(M1) and VO2(R), have a wide spectrum of functionalities useful for many potential applications in information and energy technologies. However, synthesis of phase pure materials, especially in thin film forms, has been a challenging task due to the fact that the VO2 polymorphs are closely related to each other in a thermodynamic framework. Here, we report epitaxial stabilization of the VO2 polymorphs to synthesize high quality single crystalline thin films and study the phase stability of these metastable materials. We selectively deposit all the phases on various perovskite substrates with different crystallographic orientations. By investigating the phase instability, phonon modes and transport behaviours, not only do we find distinctively contrasting physical properties of the VO2 polymorphs, but that the polymorphs can be on the verge of phase transitions when heated as low as ~400 °C. Our successful epitaxy of both VO2(A) and VO2(B) phases, which are rarely studied due to the lack of phase pure materials, will open the door to the fundamental studies of VO2 polymorphs for potential applications in advanced electronic and energy devices.

  20. Formation and photodepletion of cluster ion-messenger atom complexes in a cold ion trap: Infrared spectroscopy of VO+, VO2+, and VO3+

    Science.gov (United States)

    Brmmer, Mathias; Kaposta, Cristina; Santambrogio, Gabriele; Asmis, Knut R.

    2003-12-01

    A novel experimental technique is described in which radiation from a free electron laser is used to measure infrared spectra of gas-phase cluster ions via vibrational predissociation of the corresponding ion-messenger atom complexes. The weakly bound complexes are formed in a temperature-controllable, radio frequency ion trap. This technique is applied to the study of the vibrational spectroscopy of the monovanadium oxide cluster cations VO+, VO2+, and VO3+.

  1. Formation and photodepletion of cluster ion-messenger atom complexes in a cold ion trap: Infrared spectroscopy of VO+, VO2+, and VO3+

    International Nuclear Information System (INIS)

    A novel experimental technique is described in which radiation from a free electron laser is used to measure infrared spectra of gas-phase cluster ions via vibrational predissociation of the corresponding ion-messenger atom complexes. The weakly bound complexes are formed in a temperature-controllable, radio frequency ion trap. This technique is applied to the study of the vibrational spectroscopy of the monovanadium oxide cluster cations VO+, VO2+, and VO3+

  2. Middleware for Data Visualization in VO-enabled Data Archives

    CERN Document Server

    Zolotukhin, Ivan

    2007-01-01

    We present a middleware for visualization and exploration of complex datasets in a VO framework, that performs interaction between data archives and existing VO client applications using PLASTIC. It comprises: (1) PLASTIC-enabled Java control applet, integrated into archive web-pages and interacting with VO applications; (2) cross-browser compatible JavaScript part managing PLASTIC-aware VO Clients (launch, data manipulation) by means of Java LiveConnect. This (or similar) solution is an essential for the new generation VO-enabled data archives providing access to complex observational and theoretical datasets (3D-spectroscopy, N-body simulations, etc.) through web-interface. Thanks to PLASTIC capabilities it is possible to start all necessary client software with a single-click in the archive query result page in a web-browser. This simplifies the scientific usage of the VO resources and makes it easy even for users with no experience in the VO technologies.

  3. Middleware for Data Visualization in VO-enabled Data Archives

    Science.gov (United States)

    Zolotukhin, I.; Chilingarian, I.

    2008-08-01

    We present middleware for visualization and exploration of complex datasets in a VO framework, that performs interaction between data archives and existing VO client applications using PLASTIC. It comprises: (1) PLASTIC-enabled Java control applet, integrated into archive web-pages and interacting with VO applications; (2) cross-browser compatible JavaScript part managing PLASTIC-aware VO Clients (launch, data manipulation) by means of Java LiveConnect. This (or similar) solution is an essential for the new generation VO-enabled data archives providing access to complex observational and theoretical datasets (3D-spectroscopy, N-body simulations, etc.) through web-interface. Thanks to PLASTIC capabilities it is possible to start all necessary client software with a single-click in the archive query result page in a web-browser. This simplifies the scientific usage of the VO resources and makes it easy even for users with no experience in the VO technologies.

  4. Electrical oscillation in Pt/VO2 bilayer strips

    International Nuclear Information System (INIS)

    We report on the observation of stable electrical oscillation in Pt/vanadium dioxide (VO2) bilayer strips, in which the Pt overlayer serves the dual purposes of heating up the VO2 and weakening the electric field in the VO2 layer. Systematic measurements in an ultrahigh vacuum nanoprobe system show that the oscillation frequency increases with the bias current and/or with decreasing device dimension. In contrast to most VO2-based oscillators reported to date, which are electrically triggered, current-induced Joule heating in the Pt overlayer is found to play a dominant role in the generation of oscillation in Pt/VO2 bilayers. A simple model involving thermally triggered transition of VO2 on a heat sink is able to account for the experimental observations. The results in this work provide an alternative view of the triggering mechanism in VO2-based oscillators

  5. Modular VO oriented Java EE service deployer

    Science.gov (United States)

    Molinaro, Marco; Cepparo, Francesco; De Marco, Marco; Knapic, Cristina; Apollo, Pietro; Smareglia, Riccardo

    2014-07-01

    The International Virtual Observatory Alliance (IVOA) has produced many standards and recommendations whose aim is to generate an architecture that starts from astrophysical resources, in a general sense, and ends up in deployed consumable services (that are themselves astrophysical resources). Focusing on the Data Access Layer (DAL) system architecture, that these standards define, in the last years a web based application has been developed and maintained at INAF-OATs IA2 (Italian National institute for Astrophysics - Astronomical Observatory of Trieste, Italian center of Astronomical Archives) to try to deploy and manage multiple VO (Virtual Observatory) services in a uniform way: VO-Dance. However a set of criticalities have arisen since when the VO-Dance idea has been produced, plus some major changes underwent and are undergoing at the IVOA DAL layer (and related standards): this urged IA2 to identify a new solution for its own service layer. Keeping on the basic ideas from VO-Dance (simple service configuration, service instantiation at call time and modularity) while switching to different software technologies (e.g. dismissing Java Reflection in favour of Enterprise Java Bean, EJB, based solution), the new solution has been sketched out and tested for feasibility. Here we present the results originating from this test study. The main constraints for this new project come from various fields. A better homogenized solution rising from IVOA DAL standards: for example the new DALI (Data Access Layer Interface) specification that acts as a common interface system for previous and oncoming access protocols. The need for a modular system where each component is based upon a single VO specification allowing services to rely on common capabilities instead of homogenizing them inside service components directly. The search for a scalable system that takes advantage from distributed systems. The constraints find answer in the adopted solutions hereafter sketched. The development of the new system using Java Enterprise technologies can better benefit from existing libraries to build up the single tokens implementing the IVOA standards. Each component can be built from single standards and each deployed service (i.e. service components instantiations) can consume the other components' exposed methods and services without the need of homogenizing them in dedicated libraries. Scalability can be achieved in an easier way by deploying components or sets of services on a distributed environment and using JNDI (Java Naming and Directory Interface) and RMI (Remote Method Invocation) technologies. Single service configuration will not be significantly different from the VO-Dance solution given that Java class instantiation that benefited from Java Reflection will only be moved to Java EJB pooling (and not, e.g. embedded in bundles for subsequent deployment).

  6. The Na2O-CaO-V2O5 system with 0-50 mol. % V2O5

    International Nuclear Information System (INIS)

    The data on binary and ternary oxide compounds related to the Na2O-CaO-V2O5 system in the area of Na2O-NaV3-Ca(VO3)2-CaO are studied. Formation of sodium vanadates NaVO3, Na5V3O10, Na3VO4 and calcium vanadates Ca(VO3)2, Ca2V2O7, Ca3(VO4)2, Ca7V4O17, binary vanadates Na2Ca(VO3)4, Na3Ca2V3O11, NaCaVO4, NaCa4(VO4)2 and solid solution on the β-Ca3(VO4)2 basis is confirmed. Formation of Ca4V2O9, Ca5V2O10, Na2CaV2O7 and Na4C12(V2O7)7 is not confirmed. Formation of the binary pyrovanadate of the Na2Ca-(V2O7)4 composition is established. The IR-spectra are studied for five vanadates. Elementary three-component systems in the area under consideration are identified and the phase diagram for subsolidus temperatures is plotted

  7. Estimativa das contribuies dos sistemas anaerbio ltico e altico durante exerccios de cargas constantes em intensidades abaixo do VO2max / Estimation of contributions of the anaerobic lactic and alactic systems during constant-load exercises at intensities below the VO2max

    Scientific Electronic Library Online (English)

    Marcos David, Silva-Cavalcante; Renata Gonalves, Silva; Rodrigo Poles, Urso; Rogrio Carvalho, Silva; Carlos Rafaell, Correia-Oliveira; Victor Gustavo Ferreira, Santos; Adriano Eduardo, Lima-Silva; Rmulo, Bertuzzi.

    2013-06-01

    Full Text Available O objetivo do estudo foi estimar as contribuies do metabolismo anaerbio ltico (MAL) e altico (MAA) em intensidades abaixo do consumo mximo de oxignio (VO2max). Dez homens (23 4 anos, 176,4 6,8 cm, 72,4 8,2 kg, 12,0 4,5 % de gordura corporal) realizaram um teste progressivo at a exaus [...] to voluntria para identificao do VO2max, da potncia correspondente ao VO2max (WVO2max) e do segundo limiar ventilatrio (LV2). Na segunda e na terceira visita foram realizados seis testes de cargas constantes (trs testes por sesso) com intensidades abaixo do VO2max. Houve uma predominncia do MAL sobre o MAA durante os exerccios submximos a partir da intensidade correspondente ao LV2, sendo significativamente maior em 90% VO2max (p Abstract in english The purpose this study was that estimated contributions of the anaerobic lactic (MAL) and alactic (MAA) metabolism during constant load exercises at intensities below the maximal oxygen capacity uptake (VO2max). Ten males (23 4 years, 176.4 6.8 cm, 72.4 8.2 kg, 12.0 4.5 % of fat body) perfor [...] med in the first visit a progressive test until exhaustion to identification of VO2max, power output corresponding to the VO2max (WVO2max) and second ventilatory threshold (LV2). On the second and third visit, the participants performed six constant workload tests (3 per session) with intensities below VO2max. There was a predominance of MAL about MAA during the exercises sub-maximal from intensity corresponding to the LV2, being significantly higher at 90% VO2max (p

  8. Biomasa acumulada e indicadores de calidad nutritiva en cebadilla chaquea (Bromus auleticus Trinius ex Nees)

    Scientific Electronic Library Online (English)

    E.G.R, Bustamante; M.A, Ruiz; E, Morici; F.J, Babinec; A.B, Pordomingo.

    2012-12-01

    Full Text Available Bromus auleticus (cebadilla chaquea) es considerada uno de los recursos forrajeros ms promisorios del Cono Sur. Presenta variacin entre poblaciones que ha sido determinada para diversos caracteres vegetativos, lo cual podra traducirse en diferencias de produccin y calidad de forraje. El objetiv [...] o del presente estudio fue evaluar dos procedencias de cebadilla chaquea (Argentina y Uruguay) para biomasa acumulada e indicadores de calidad nutritiva en dos perodos del ao (verano-otoo y otoo-primavera). Se compararon cinco clones uruguayos (U) y cinco argentinos (A), dispuestos al azar en surcos distanciados a 1 m entre s, con 10 plantas cada uno. Se determin biomasa acumulada por planta (B) y calidad, midiendo Fibra Detergente Neutra (FDN), Protena Bruta (PB) y Digestibilidad de la Materia Seca (DMS) en dos momentos del ao. En general, la biomasa fue de baja calidad debido al momento en que se realizaron los cortes, lo que limita el alcance de los resultados. Sin embargo, las diferencias observadas entre los clones en este estado de desarrollo podran indicar la existencia de variacin entre genotipos de cebadilla chaquea U y A en biomasa y calidad nutritiva. En biomasa acumulada no se observ efecto significativo de origen. En todas las variables de calidad evaluadas en verano-otoo, se encontraron diferencias significativas entre orgenes. En otooprimavera, las diferencias entre orgenes fueron significativas para DMS. Los clones U presentaron mayor PB, menor FDN y mayor DMS. Dentro de cada origen, los argentinos presentaron menos diferencias que los uruguayos, tanto en biomasa acumulada como en calidad. Para ninguno de los clones A o U se encontr coincidencia entre mayor biomasa y mayor calidad. Abstract in english Bromus auleticus (chaquea bromegrass) may be considered as one of the most valuable forage species for the Southern Cone. This species shows variation among populations, determined in diverse vegetative characters, which could result in differences in production and forage quality. The objective [...] of this study was to evaluate two origins of Bromus auleticus (Argentina and Uruguay) for characters of biomass accumulated and quality in two periods of the year (Summer-Autumn and Autumn-Spring). Five Uruguayan (U) and Argentine (A) clones were compared, it were randomly arranged in rows spaced one meter of each other, with 10 plants each one. Biomass accumulated per plant (B) and biomass quality were determined in two times of the year measuring neutral detergent fiber (NDF), crude protein (CP) and dry mater digestibility (DMD). In general, quality of biomass was poor due to time cuttings, limiting the scope of the results. However, differences between the clones in this stage of development could be indicating the presence of variation among genotypes of chaquea prairie grass U and A in biomass and nutritional quality. Significant effect of origin for B was not observed. In all biomass quality variables evaluated in Summer-Autumn, significant differences between origins were found. In Autumn-Spring, differences between origins were significant in DMD. U clones showed more CP, less NDF and higher DMD. Within each origin, A showed less differences than U both in B and quality. Concerning A or U clones, no coincidence between high biomass and high quality was found.

  9. Vplyv pesticdov na spolo?enstvo aktinomyct vo vysokohorskej pde.

    Czech Academy of Sciences Publication Activity Database

    Seleiov, Z.; Javorekov, S.; Krit?fek, Vclav; Chro?kov, Alica

    Bratislava : Vydavate?stvo Univerzity Komenskho, 2010, s. 120-127. ISBN 978-80-223-2796-1. [ivot v pde /11./. Bratislava (SK), 26.01.2010-27.01.2010] R&D Projects: GA Mk LC06066 Grant ostatn: SAV(SK) 1/0404/09; SAV(SK) 3/6228/08 Institutional research plan: CEZ:AV0Z60660521 Keywords : pesticides * actinomycetes * grassland Subject RIV: EH - Ecology, Behaviour

  10. Steganography of VoIP streams

    CERN Document Server

    Mazurczyk, Wojciech

    2008-01-01

    In this paper, we circumscribe available steganographic techniques that can be used for creating covert channels for VoIP (Voice over Internet Protocol) streams. Apart from characterizing existing steganographic methods we provide new insights by presenting two new techniques. First one is network steganography solution and exploits free/unused fields of the RTCP (Real-Time Control Protocol) and RTP (Real-Time Transport Protocol) protocols. The second method provides hybrid storage-timing covert channel by utilizing delayed audio packets. The results of the experiment, that was performed, regardless of steganalysis, to estimate a total amount of data that can be covertly transferred in VoIP RTP stream during the typical call, are also included in this article.

  11. Simulink based VoIP Analysis

    CERN Document Server

    Singh, Hardeep; Mian, M

    2010-01-01

    Voice communication over internet not be possible without a reliable data network, this was first available when distributed network topologies were used in conjunction with data packets. Early network used single centre node network in which a single workstation (Server) is responsible for the communication. This posed problems as if there was a fault with the centre node, (workstation) nothing would work. This problem was solved by the distributed system in which reliability increases by spreading the load between many nodes. The idea of packet switching & distributed network were combined, this combination were increased reliability, speed & responsible for voice communication over internet, Voice-over-IP (VoIP)These data packets travel through a packet-switched network such as the Internet and arrive at their destination where they are decompressed using a compatible Codec (audio coder/decoder) and converted back to analogue audio. This paper deals with the Simulink architecture for VoIP network.

  12. Secure Session Mobility for VoIP

    OpenAIRE

    Dzaferagic, Samir

    2008-01-01

    High data rate wireless packet data networks have made real-time IP based services available through mobile devices. At the same time, differences in the characteristics of radio technologies (802.11/WiFi and 3G networks) make seamless handoff across heterogeneous wireless networks difficult. Despite this, many believe that the ultimate goal of next generation networks (often referred to as the fourth generation) is to allow convergence of such dissimilar heterogeneous networks. Supporting vo...

  13. Lattice relaxation and ferromagnetic character of (LaVO3) m/SrVO3superlattices

    KAUST Repository

    Schuster, Cosima B.

    2013-08-01

    The experimental observation that vanadate superlattices (LaVO 3)m/SrVO3 show ferromagnetism up to room temperature (Lüders U. et al., Phys. Rev. B, 80 (2009) 241102(R)) is investigated by means of density functional theory, and the band structure for m = 5 and 6 is calculated. A buckling of the interface VO2 layers is found in both cases, but subtle differences in bond length lead to very different properties for even and odd values of m: in the even case, the two interface VO2 layers effectively decouple from the adjacent LaO layers due to a strong bond length enhancement. This results into a local inversion of the orbital occupancy and to the confinement of the charge carriers. In the odd case, the amplitude of the bond length variation is smaller, so that the charge carriers spill into the deeper-lying VO2 layers, and spin-polarised interfaces are obtained. © Copyright EPLA, 2013.

  14. ESA Science Archives and associated VO activities

    Science.gov (United States)

    Arviset, Christophe; Baines, Deborah; Barbarisi, Isa; Castellanos, Javier; Cheek, Neil; Costa, Hugo; Fajersztejn, Nicolas; Gonzalez, Juan; Fernandez, Monica; Laruelo, Andrea; Leon, Ignacio; Ortiz, Inaki; Osuna, Pedro; Salgado, Jesus; Tapiador, Daniel

    ESA's European Space Astronomy Centre (ESAC), near Madrid, Spain, hosts most of ESA space based missions' scientific archives, in planetary (Mars Express, Venus Express, Rosetta, Huygens, Giotto, Smart-1, all in ESA Planetary Science Archive), in astronomy (XMM-Newton, Herschel, ISO, Integral, Exosat, Planck) and in solar physics (Soho). All these science archives are operated by a dedicated Science Archives and Virtual Observatory Team (SAT) at ESAC, enabling common and efficient design, development, operations and maintenance of the archives software systems. This also ensures long term preservation and availability of such science archives, as a sustainable service to the science community. ESA space science data can be accessed through powerful and user friendly user interface, as well as from machine scriptable interface and through VO interfaces. Virtual Observatory activities are also fully part of ESA archiving strategy and ESA is a very ac-tive partner in VO initiatives in Europe through Euro-VO AIDA and EuroPlanet and worldwide through the IVOA (International Virtual Observatory Alliance) and the IPDA (International Planetary Data Alliance).

  15. Cloudspace: virtual environments in the VO

    Science.gov (United States)

    Graham, M. J.; Williams, R. D.

    2008-08-01

    The grid community is moving towards providing on-demand computing in the form of virtual workspaces - abstracted execution environments that are dynamically made available to authorized clients. In part this is a reaction to market forces represented by such commercial initiatives as Amazon EC2 and in part a solution to hot service deployment. One danger, though, is that a multiplicity of implementations will lead to a lack of interoperability. Such a concern in the VO regarding distributed data storage led to the development of VOSpace, a lightweight abstraction layer that sits on top of existing storage solutions such as SRB. In this paper, we introduce Cloudspace, a resource-oriented extension of VOSpace, that incorporates UWS, the VO pattern for managing asynchronous services, to form a natural habitat for virtual environments in the VO. A notable feature of the Cloudspace concept is that distributed data and computing can be managed seamlessly through a single mechanism thus making the astronomer's life easier as we move into a new era of sophisticated computational astronomy.

  16. What are suspicious VoIP delays?

    CERN Document Server

    Mazurczyk, Wojciech; Szczypiorski, Krzysztof

    2010-01-01

    Voice over IP (VoIP) is unquestionably the most popular real-time service in IP networks today. Recent studies have shown that it is also a suitable carrier for information hiding. Hidden communication may pose security concerns as it can lead to confidential information leakage. In VoIP, RTP (Real-time Transport Protocol) in particular, which provides the means for the successful transport of voice packets through IP networks, is suitable for steganographic purposes. It is characterised by a high packet rate compared to other protocols used in IP telephony, resulting in a potentially high steganographic bandwidth. The modification of an RTP packet stream provides many opportunities for hidden communication as the packets may be delayed, reordered or intentionally lost. In this paper, to enable the detection of steganographic exchanges in VoIP, we examined real RTP traffic traces to answer the questions, what do the "normal" delays in RTP packet streams look like? and, is it possible to detect the use of know...

  17. A novel inorganic precipitation-peptization method for VO2 sol and VO2 nanoparticles preparation: Synthesis, characterization and mechanism.

    Science.gov (United States)

    Li, Yao; Jiang, Peng; Xiang, Wei; Ran, Fanyong; Cao, Wenbin

    2016-01-15

    In this paper, a simple, safe and cost-saving precipitation-peptization method was proposed to prepare VO2 sol by using inorganic VOSO4-NH3?H2O-H2O2 reactants system in air under room temperature. In this process, VOSO4 was firstly precipitated to form VO(OH)2, then monometallic species of VO(O2)(OH)(-) were formed through the coordination between VO(OH)2 and H2O2. The rearrangement of VO(O2)(OH)(-) in a nonplanar pattern and intermolecular condensation reactions result in multinuclear species. Finally, VO2 sol is prepared through the condensation reactions between the multinuclear species. After drying the obtained sol at 40C, VO2 xerogel exhibiting monoclinic crystal structure with the space group of C2/m was prepared. The crystal structure of VO2 nanoparticles was transferred to monoclinic crystal structure with the space group of P21/c (VO2(M)) by annealing the xerogel at 550C. Both XRD and TEM analysis indicated that the nanoparticles possess good crystallinity with crystallite size of 34.5nm as estimated by Scherrer's method. These results suggest that the VO2 sol has been prepared successfully through the proposed simple method. PMID:26433476

  18. Urchin-like m-LaVO4 and m-LaVO4/Ag microspheres: Synthesis and characterization

    International Nuclear Information System (INIS)

    The semiconductor nanostructures decorated with noble metals have attracted increasing attention due to their interesting physical and chemical properties. In this work, urchin-like monoclinic (m-) LaVO4 microspheres were prepared by a hydrothermal method and used as a template to fabricate Ag nanoparticle-decorated m-LaVO4 composites. The morphology and structure were characterized by transmission electron microscope, high-resolution transmission electron microscope, scanning electron microscope, and energy-dispersive X-ray. It was found that Ag nanoparticles with narrow size distribution were uniformly loaded on urchin-like m-LaVO4 microspheres, and the resulted composite microspheres showed distinct surface plasmon absorption band compared to pure m-LaVO4 microspheres. Photocatalytic activities of as-prepared samples were examined by studying the degradation of methyl orange solutions under visible-light irradiation (> 400 nm). Results clearly showed that urchin-like m-LaVO4/Ag microspheres possess much higher photocatalytic activity than pure m-LaVO4 microspheres and P25. - Highlights: • m-LaVO4/Ag composites microspheres were fabricated by a hydrothermal method. • m-LaVO4 microspheres show higher photocatalytic activity than m-LaVO4 microspheres. • m-LaVO4/Ag microspheres exhibit a good stability

  19. Efecto de nutrientes sobre la produccin de biomasa del hongo medicinal Ganoderma lucidum

    Directory of Open Access Journals (Sweden)

    Ana Mara Torres Lpez

    2011-04-01

    Full Text Available Effect of nutrients in the biomass production of the medicinal mushroom Ganoderma lucidumTtulo corto: Efecto de nutrientes sobre la produccin de G. lucidumResumen El hongo Ganoderma lucidum, en los constituyentes de su biomasa, tiene compuestos con propiedades benficas para la salud; es por esto que el conocimiento de las condiciones nutricionales adecuadas para su crecimiento permitir su produccin industrial y a bajo costo. En este trabajo se evalu a nivel de matraz el efecto de la relacin C/N, y la presencia de diferentes fuentes de carbono, nitrgeno y micronutrientes sobre la produccin de biomasa. Empleando glucosa y peptona como fuentes de carbono y nitrgeno, respectivamente, se encontr una relacin C/N ptima de 16,7:1 para la cual la mxima produccin de biomasa fue de 25 g/L. Manteniendo esta relacin C/N, y sustituyendo la glucosa por lactosa o harina de cebada y la peptona por extracto de levadura, la produccin de biomasa se increment a 35 g/L. En presencia de harina de cebada la adicin al medio de cultivo de sales de Mg y K, y de tiamina, no gener un mayor incremento en la produccin de biomasa. La produccin de biomasa de G. lucidum se ve favorecida por la presencia en el medio de cultivo de relaciones C/N cercanas a las reportadas conforme a la composicin tpica de los hongos, as como por la presencia de sustratos complejos como la harina de cebada que le aportan adems de la fuente de carbono micronutrientes necesarios para su desarrollo.Palabras clave: harina de cebada, relacin C/N, micronutrientes, fuentes de carbono, fuentes de nitrgeno. AbstractGanoderma lucidum fungus has some biomass components with beneficial health properties. The knowledge about its nutritionals requirements for growing will favor its industrial production at lower cost. In this work, the effect of C/N ratio, the presence of different carbon, nitrogen and micronutrients sources, on fungal biomass production, were evaluated. Using glucose and peptone as carbon and nitrogen sources, respectively, an optimal C/N ratio of 16,7:1 was found, for which the maximal biomass production was 25 g/L. Replacing glucose by lactose or barley flour and peptone by yeast extract at the same C/N ratio, the biomass production was enhanced to 35 g/L. With barley flour in the culture medium, the presence of Mg and K salts and thiamine did not turn out into a major increase of biomass. The G. lucidum biomass production is promoted by C/N ratios in the culture medium nearly equivalent to that found in the fungus, as well as the presence of complex substrates as barley flour which, additionally, contributes with important micronutrients along with the carbon source. Key words: Barley flour, C/N ratio, micronutrients, carbon sources, nitrogen sources.

  20. Evidence of field-induced nucleation switching in opal: VO2 composites and VO2 films

    Science.gov (United States)

    Pevtsov, A. B.; Medvedev, A. V.; Kurdyukov, D. A.; Il'Inskaya, N. D.; Golubev, V. G.; Karpov, V. G.

    2012-01-01

    We show that electrical switching in opal-VO2 composites is governed by the electric field rather than voltage or current. This makes it similar to switching in chalcogenide glasses with the underlying mechanism identified as the field induced nucleation. However, the observed bias dependence of switching delay time is found to be noticeably different from that of standard VO2 films on smooth substrates. This difference is attributed to the disorder effects in polycrystalline structures. The model of field induced nucleation is shown to apply when properly modified to account for that disorder.

  1. Correlao entre as medidas direta e indireta do VO2max em atletas de futsal Correlacin entre las medidas directa e indirecta del VO2max en atletas de futsal Correlation between direct and indirect VO2max measurements in indoor soccer players

    OpenAIRE

    Anna Myrna Jaguaribe de Lima; Daniele Vanusca Gomes Silva; Alexandre Oscar Soares de Souza

    2005-01-01

    A importncia das qualidades morfofuncionais na melhora do rendimento nos esportes aumentou o interesse no aprimoramento dos nveis de aptido fsica dos atletas. No entanto, h poucos estudos sobre as variveis fisiolgicas do futsal disponveis na literatura cientfica mundial. Dessa forma, o objetivo deste estudo foi verificar a existncia de correlao entre os testes de medida direta e indireta do VO2max, em jogadores de futsal. Foram analisados 13 jogadores de futsal, com idade de 18,6 ...

  2. Factores del manejo para estabilizar la produccin de biomasa con leguminosas en el trpico

    Directory of Open Access Journals (Sweden)

    T. E. Ruiz

    2006-01-01

    Full Text Available Este material tiene como objetivo abundar acerca de aquellos factores del manejo que conduzcan a estabilizar la produccin de biomasa en sistemas ganaderos en el trpico. Es obvio que los sistemas mejorados y bien manejados de pasturas de gramneas y leguminosas, en cualquiera de sus alternativas, son opciones para lograr la sostenibilidad. Una concepcin ms amplia y profunda es la relativa a los estudios de pasturas mixtas; stos, deben tener un enfoque ms biolgico por lo que, adems de considerar el ambiente en el cual se desarrollan y crecen, hay que incluir la forma en que los componentes vegetales se manifiestan en las especies implicadas del agroecosistema. Aqu no podemos olvidar el efecto del animal. Los problemas asociados con la persistencia se reconocen cada vez ms como una preocupacin real. Los diversos factores que controlan la permanencia de las especies forrajeras se agrupan en aquellos que pueden ser manejados y controlados por el productor, as como en los que ste no puede intervenir. Es por ello que las producciones animales y de otro tipo, derivados de estos sistemas, varan positivamente en el tiempo, en la medida en que se va consolidando la relacin suelo /planta /animal. De esta correspondencia no puede quedar excluido el papel interactuante y modificador del hombre con los elementos antes sealados. La produccin de biomasa es una actividad multidisciplinaria; de ah que el xito de su funcionamiento est condicionado al conocimiento de las interacciones entre sus componentes, as como entre stos y el medio ambiente, lo cual permitir la generacin de estrategias de manejo acordes con la ecologa que conduzcan a mejorar la productividad y la sostenibilidad del agroecosistema. Por tanto, la produccin de biomasa constituye un elemento determinante en el xito y la eficiencia de los sistemas con leguminosas.

  3. INCORPORACIN DE BIOMASA EN UN SUELO VERTISOL Y SU RELACIN CON LA DENSIDAD DE COMPACTACIN

    Directory of Open Access Journals (Sweden)

    Euriel Milln

    2013-01-01

    Full Text Available Un suelo compactado evidencia un deterioro en las propiedades fsicas y afecta el crecimiento de las plantas. El objetivo de este estudio fue evaluar los efectos que produce la incorporacin de biomasa en un ensayo de compactacin, a un suelo de explotacin ganadera sobre las curvas de compactacin del mismo. Se utiliz un suelo Vertisol de Sincelejo (Sucre. Se analizaron las propiedades fsicas del suelo, como textura, densidad real y aparente; densidades mximas de compactacin y contenidos de humedad en los que se alcanzaba dicha compactacin. Se determin mediante software estadstico la relacin que existe entre la incorporacin de materia orgnica y las variaciones en la densidad mxima y la humedad del suelo. Para determinar la densidad mxima del suelo y humedad crtica se utiliz diseo de bloques completos al azar, con tres repeticiones. Los tratamientos estudiados corresponden a un factorial 2 X 4, siendo dos los tipos de materia orgnica (hmeda y seca, y cuatro las cantidades de materia orgnica. Se encontr que la densidad mxima en condiciones normales (sin incorporacin de materia orgnica es de 1,421 g cm-3 y 26,573% de humedad; se alcanzaron valores de 1,406 g cm-3 y 28,074%, y 1,379 g cm-3 y 26,833% para incorporaciones de 20 Mg ha-1 de biomasa hmeda y seca respectivamente. La densidad mxima con respecto a la cantidad y tipo de materia orgnica incorporada seala un efecto estadsticamente significativo. La incorporacin de biomasa al suelo Vertisol ayuda a disminuir las densidades mximas de compactacin, y aumenta el contenido de humedad.

  4. La biomasa en la producción de electricidad en España

    Directory of Open Access Journals (Sweden)

    Espejo Marín, Cayetano

    2005-06-01

    Full Text Available The generation of electricity using biomass began in Spain in the mid-1990s. In this paper, we examine the combustible products used in the generation of this type of electricity, the legal framework protecting its production, the evolution of the installed power and its territorial distribution, the environmental impact of biomass as a renewable energy, the energy policy supporting this technology and the problems for the development of biomass as a energy source in Spain.

    [es] La producción de electricidad con biomasa comienza su desarrollo en España a mediados de los años noventa. En este artículo se analizan los productos combustibles de biomasa destinados a la generación de electricidad, el marco legal que protege esta producción, la evolución de la potencia instalada y su distribución territorial, el impacto ambiental de la biomasa como energía renovable, la política energética de apoyo a esta tecnología, y los problemas para el desarrollo de la biomasa como fuente energética en España. [fr] La biomasse dans la production d´électricité en Espagne. La production d'électricité avec biomasse commence son développement en Espagne vers le milieu des années quatre-vingt-dix. Dans cet article nous analysons les produits combustibles de biomasse destines à engendrer de l'électricité, le cadre légal qui protégé cette production, l'évolution de la puissance installée, la répercussion de l'environnement de la biomasse comme énergie renouvelable, la politique énergétique de soutien à cette technologie et les problèmes pour le développement de la biomasse comme source énergétique en Espagne.

  5. Recuperacin de la biomasa mediante la sucesin secundaria, Cordillera Central de los Andes, Colombia

    Scientific Electronic Library Online (English)

    Jorge Ignacio, del Valle; Hctor Ivn, Restrepo; Mnica Mara, Londoo.

    2011-09-01

    Full Text Available En bosques secundarios premontanos tropicales es escasa la informacin sobre el tiempo requerido para recuperar la biomasa area y subterrnea de los primarios. Por lo tanto, establecimos 33 parcelas de 0.1ha entre 550 y 1 700m en bosques secundarios que cubran estadios serales de 3 a 36 aos y est [...] imamos la biomasa de las plantas y de las races gruesas con ecuaciones locales. As como la biomasa de las pasturas y barbechos por cosecha de 54 y 18 parcelas, respectivamente. Tambin se calcul la edad de las parcelas con informantes locales, sensores remotos, C14 y anillos de crecimiento. En cada parcela medimos la biomasa area viva por hectrea (Bav) y la de las races gruesas por hectrea (Brg). Modelamos la Bav y Brg en funcin de la edad mediante la ecuacin de von Bertalanfy con asntotas de 247t/ha (Bav) y 66t/ha (Brg) resultantes de la medicin de 33 parcelas de 0.1ha en los bosques primarios. Con la razn Brg/Bav=f(t) estimamos 87 aos para que los bosques secundarios recuperen la Bav existente en los primarios y 217 aos para recuperar la Brg. La tasa mxima de crecimiento instantneo de la Bav fue 6.95t/ha/ao a los 10 aos y la tasa media mxima de crecimiento 6.26t/ha/ao a los 17 aos. La media ponderada de la tasa de crecimiento absoluto de la Bav alcanz 4.57t/ha/ao y la relativa 10% anual. La razn Brg/Bav inicialmente aumenta muy aceleradamente hasta 4-5 aos (25%), luego disminuye hasta 25 aos (18%) para luego incrementar hasta 26.7 Abstract in english Biomass recovery through secondary succession in the Cordillera Central de los Andes, Colombia. Estimations on biomass recovery rates by secondary tropical forests are needed to understand the complex tropical succession, and their importance on CO2 capture, to offset the warming of the planet. We c [...] onducted the study in the Porce River Canyon between 550 and 1 700m.a.s.l. covering tropical and premontane moist belts. We established 33 temporary plots of 50mx20m in secondary forests, including fallows to succesional forests, and ranging between 3 and 36 years old; we measured the diameter at breast height (D) of all woody plants with D?5cm. In each one of these plots we established five 10mx10m subplots, in which we measured the diameter betweem 1cm?D

  6. Transformacin de biomasa en biocombustibles de segunda generacin / From biomass to second generation biofuels

    Scientific Electronic Library Online (English)

    Laura, Faba; Eva, Daz; Salvador, Ordez.

    2014-11-01

    Full Text Available El agotamiento de las materias primas no renovables, as como la creciente conciencia ambiental ha motivado la valorizacin de la biomasa para la produccin de energa. Aunque los primeros esfuerzos se centraron en el desarrollo de los biocombustibles de primera generacin -segn la materia prima co [...] n que se producen-, la tendencia actual es hacia la investigacin en los biocombustibles de segunda generacin, que permiten la transformacin de la biomasa lignocelulsica (obtenida a partir de residuos forestales o de cultivos, maderas de bajo precio o serrn) en energa. La transformacin de la madera en biocombustibles puede llevarse a cabo por vas biolgicas o qumicas. Entre las rutas qumicas, hay tres posibilidades principales: gasificacin, pirlisis o hidrlisis. Este trabajo tiene como objetivo hacer una revisin de las posibilidades para obtener biocombustibles de segunda generacin mediante procesos qumicos hidrolticos, que implica varios pasos: pretratamiento de la biomasa (que puede ser fsico o qumico), hidrlisis de la biomasa, deshidratacin de los azcares, condensacin aldlica e hidrogenacin/deshidratacin completa para obtener los alcanos lineales (biodiesel). Abstract in english The depletion of the non-renewable raw materials as petroleum, coal or natural gas as well as the increasing environmental conscience has motivated the valorization of biomass for energy production. Although the first efforts were focused on the development of the first generation biofuels -accordin [...] g to the raw material-, nowadays the research is focused on the second generation biofuels, which allows the transformation of lignocellulosic biomass (from forest or crops wastes, low-priced woods or sawdust) into energy. The transformation of wood into biofuels can be carried out by biological or chemical means. Among the chemical routes, there are three main possibilities: gasification, pyrolisis or hydrolysis. This paper aims to review the technological advances to obtain biofuels by the third route, since it allows using the most abundant forms of biomass, cellulose and hemicelluloses. This chemical process involves several steps: pretreatment of the biomass (by physical or chemical route), hydrolysis of the biomass, dehydration of sugars, aldolization and hydrogenation/dehydration until n-alcanes (biofuels) are achieved.

  7. Perspectivas del potencial energtico de la biomasa en el marco global y latinoamericano

    Directory of Open Access Journals (Sweden)

    Julin Rodrigo Quintero Gonzlez

    2015-06-01

    Full Text Available El calentamiento global y los cambios climticos que ste conlleva han fomentado desde hace algunos aos la exploracin de otros tipos de obtencin energtica para disminuir el uso del combustible fsil, siendo ste ltimo uno de los principales causantes de dicho problema ambiental. El presente artculo expone algunas investigaciones recientes sobre la bioenerga u obtencin de energa a partir de biomasa, considerada como energa limpia. Se abarcan temticas como la bioenerga y sus posibilidades desde el punto de vista energtico, teniendo en cuenta las expectativas de produccin segn su potencial o productividad energtica, adems del aporte que este tipo de tecnologa hace a la disminucin de la huella ecolgica.

  8. Estudio de la oxidacin a elevada temperatura de ocho aleaciones en atmsferas de combustin de biomasa

    Directory of Open Access Journals (Sweden)

    Berlanga-Labari, C.

    2008-08-01

    Full Text Available The combustion of biomass, especially wheat straw, generates very corrosive media particularly near the superheater tubes. Chlorine is known to be the main corrosive agent in biomass-fired plants. This paper focuses on the study of the corrosivity of such environments composed of gases and ashes, at high temperature, on eight commercial alloys with different chromium and nickel contents. These have been: AISI 347 CG (1.4550, AISI 347 FG(1.4550, AISI 316LN (1.4910, ESSHETE 1250 (1.4982, AC 66 (1.4877, X20CrMoV12:1 (1.4922 and AISI 347 coated with Inconel 625 and Inconel 686. Corrosion tests in the boiler have been performed during 8.000 h and 15.000 h at temperatures between 500 C y 550 C in the biomass plant of Sangesa (Navarra, Spain. Experimental results showed an unacceptable behaviour far the martensitic steel, acceptable far the austenitics and good far the inconels. The appearance of the corrosion attack was also investigated to obtain understanding of the corrosion mechanism. The corrosion mechanism by molten salts has been rejected. The active oxidation corrosion mechanism has been proposed as the most probable in order to interpretate the corrosion behaviour of these materials in these environments.

    La combustin de biomasa, especialmente de paja de cereal, genera un ambiente muy corrosivo, particularmente, cerca de los tubos sobrecalentadores. El cloro es el principal agente corrosivo en las plantas de biomasa. Este trabajo se centra en comprobar el comportamiento de ocho aleaciones comerciales en una ambiente de combustin de biomasa. Los materiales estudiados han sido las siguientes: AISI 347 CG (1.4550, AISI 347 FG (1.4550, AISI 316LN (1.4910, ESSHETE 1250 (1.4982, AC 66 (1.4877, X20CrMoV12:1 (1.4922 y AISI 347 recubiertos con Inconel 625 e Inconel 686. Los ensayos se han realizado en la caldera de la planta de biomasa de Sangesa (Navarra, Espaa durante 8.000 y 15.000 h a una temperatura de 500-550 C. Los resultados indican un buen comportamiento de los aceros inoxidables austenticos y de las aleaciones de Inconel, mientras que el del acero martenstico no ha sido aceptable. Se ha propuesto el mecanismo conocido como oxidacin activa para interpretar el comportamiento a la corrosin de estos materiales en estos medios.

  9. LA BIOMASA MICROBIANA EN SUELOS DE MONTAÑA CON DIFERENTES USOS: UN ESTUDIO DE LABORATORIO

    Directory of Open Access Journals (Sweden)

    A. Cruz Ruiz

    2012-01-01

    Full Text Available El uso agrícola de los suelos del Parque Nacional Nevado de Toluca (PNTT, conlleva prácticas como la utilización creciente de agroquímicos. Para investigar el efecto de la aplicación de fertilizantes nitrogenados y biocidas de uso generalizado en la zona de estudio sobre la biomasa microbiana y la mineralización del carbono (C, se realizó una incubación de suelos del PNNT con diferentes usos: bosque (bajo la copa de oyamel (Abies religiosa, destinados al pastoreo (pradera y cultivado con maíz. Con los siguientes tratamientos: sulfato deamonio (585.36 kg ha-1, urea (250 kg ha-1, 2, 4-D (1 L ha-1, captan (2 kg ha-1 y suelos sin aplicación. La mineralización del C, el nitrógeno de la biomasa microbiana (NBM y el carbono de la biomasa microbiana (CBM se midieron a los 56 días de incubación. Los resultados mostraron que el cambio de uso de suelo de bosque a cultivo disminuye la biomasa microbiana, la proporción de CBM y NBM en los suelos de cultivo fue menor en más del 55% en comparación con los suelos de bosque. Los tratamientos 2, 4-D y captan dieron lugar al decremento significativo del CBM en los suelos de bosque, hasta en un 40 %, con respecto al suelo sin aplicación. La aplicación de captan favoreció el incremento del CBM en los suelos de pradera y cultivo. El NBM aumentó en los tres suelos con diferente uso al aplicar urea. La adición de sulfato de amonio, urea, 2, 4-D amina o captan causa efectos diferenciados en los suelos de bosque, pradera y cultivo indicando que el impacto de los biocidas y fertilizantes está relacionado con la degradación de los mismos.

  10. VoIP Networks Monitoring and Intrusion Detection

    OpenAIRE

    Nassar, Mohamed

    2009-01-01

    Voice over IP (VoIP) has become a major paradigm for providing flexible telecommunication services and reducing operational costs. The large-scale deployment of VoIP has been leveraged by the high-speed broadband access to the Internet and the standardization of dedicated protocols. However, VoIP faces multiple security issues including vulnerabilities inherited from the IP layer as well as specific ones. Our objective is to design, implement and validate new models and architectures for perf...

  11. Deployment of VoIP Technology: QoS Concerns

    OpenAIRE

    Lazzez, Amor; Slimani, Thabet

    2013-01-01

    Voice over IP (VoIP) is an emerging communication service allowing voice transmission over a private or a public IP network. VoIP allows significant benefits for customers and service providers including cost savings, phone and service portability, mobility, and the integration with other applications. Nevertheless, the deployment of the VoIP technology encounters many challenges such as interoperability issues, security issues, and QoS concerns. Among these disadvantages, Q...

  12. The Astrophysical Virtual Observatory to EURO-VO Transition

    CERN Document Server

    Padovani, P

    2005-01-01

    The Astrophysical Virtual Observatory (AVO) initiative, jointly funded by the European Commission and six European organisations, had the task of creating the foundations of a regional scale infrastructure by conducting a research and demonstration programme on the VO scientific requirements and necessary technologies. The AVO project is now formally concluded. I highlight AVO's main achievements and then describe its successor, the EURO-VO project. With its three new interlinked structures, the Data Centre Alliance, the Facility Centre, and the Technology Centre, the EURO-VO is the logical next step for the deployment of an operational VO in Europe.

  13. VO-Dance an IVOA tools to easy publish data into VO and it's extension on planetology request

    Science.gov (United States)

    Smareglia, R.; Capria, M. T.; Molinaro, M.

    2012-09-01

    Data publishing through the self standing portals can be joined to VO resource publishing, i.e. astronomical resources deployed through VO compliant services. Since the IVOA (International Virtual Observatory Alliance) provides many protocols and standards for the various data flavors (images, spectra, catalogues ), and since the data center has as a goal to grow up in number of hosted archives and services providing, the idea arose to find a way to easily deploy and maintain VO resources. VO-Dance is a java web application developed at IA2 that addresses this idea creating, in a dynamical way, VO resources out of database tables or views. It is structured to be potentially DBMS and platform independent and consists of 3 main tokens, an internal DB to store resources description and model metadata information, a restful web application to deploy the resources to the VO community. It's extension to planetology request is under study to best effort INAF software development and archive efficiency.

  14. Similar foliage area but contrasting foliage biomass between young beech and spruce stands / Porovnate?n plocha avak kontrastn biomasa asimila?nch orgnov medzi mladmi porastmi buka a smreka

    Directory of Open Access Journals (Sweden)

    Konpka Bohdan

    2014-12-01

    Full Text Available Vskum sa zameral na mlad porasty buka lesnho (Fagus sylvatica a smreka oby?ajnho (Picea abies rovnakho veku (12 rokov, ve?mi podobnch dimenzi stromov, rastcich na totonom stanoviti. Na zklade odberu vzornkov celch stromov (vetky ?asti okrem jemnch kore?ov sme skontruovali alometrick vz?ahy pre stromov komponenty. Ako nezvisl premenn sa pouila hrbka na bze kme?a (d0. Modely vyjadrili nielen biomasu konrov, kme?a, hrubch kore?ov a asimila?nch orgnov, ale aj plochu asimila?nch orgnov a pecifick listov plochu (specific leaf area; SLA. Zistili sme, e zkladn morfologick vlastnosti asimila?nch orgnov varrovali pri obidvoch drevinch pozd? vertiklneho profilu koruny. V prpade smreka sa zistili odlin hodnoty plochy ihlc a SLA medzi jednotlivmi ro?nkmi ihlc. Na rovni stromu mali buky ove?a viac biomasy drevnch ?ast ako smreky, opa?n situcia bola pri asimila?nch orgnoch. Preto hodnoty podielu medzi biomasou asimila?nch orgnov a celkovou biomasou stromu, ako aj pomeru medzi plochou asimila?nch orgnov a celkovou biomasou stromu boli vrazne vyie pri smreku ne buku. Na rovni porastu mala smre?ina vyie hodnoty indexu listovej plochy, t. j. LAI (18,64 m2.m?2 v porovnan s bu?inou (12,77 m2.m?2. Km biomasa asimila?nch orgnov bola 4,6-krt v?ia v smrekovom ne v bukovom poraste, biomasa drevnch ?asti bola porovnate?n v obidvoch porastoch. Tieto kontrasty nazna?uj vrazne odlin rastov stratgiu, resp. alokciu biomasy medzi bu?inami a smre?inami v mladch tdich

  15. VO-compliant workflows and science gateways

    Science.gov (United States)

    Castelli, G.; Taffoni, G.; Sciacca, E.; Becciani, U.; Costa, A.; Krokos, M.; Pasian, F.; Vuerli, C.

    2015-06-01

    Workflow and science gateway technologies have been adopted by scientific communities as a valuable tool to carry out complex experiments. They offer the possibility to perform computations for data analysis and simulations, whereas hiding details of the complex infrastructures underneath. There are many workflow management systems covering a large variety of generic services coordinating execution of workflows. In this paper we describe our experiences in creating workflows oriented science gateways based on gUSE/WS-PGRADE technology and in particular we discuss the efforts devoted to develop a VO-compliant web environment.

  16. Biomassa de rotferos em ambientes dulccolas: Reviso de mtodos e fatores influentes / Rotifer biomass in freshwater environments: Review of methods and influencing factors / Biomasa de rotferos en ambientes dulciacucolas: Revisin de mtodos y factores influyentes

    Scientific Electronic Library Online (English)

    Dayane, Christian Rossa; Claudia, Costa Bonecker; Leandro, Junio Fulone.

    2007-04-01

    Full Text Available A biomassa de uma comunidade aqutica fornece informaes quantitativas da matria orgnica disponvel nos diferentes nveis trficos. As dificuldades metodolgicas para se estimar a biomassa zooplanctnica explicam os poucos estudos existentes, principalmente no Brasil. Neste estudo objetiva-se des [...] crever as metodologias mais utilizadas na estimativa da biomassa de rotferos, analisar suas vantagems e desvantagems, comparar resultados obtidos com cada tcnica, e investigar alguns fatores que influenciam sua biomassa. A estimativa mais utilizada a determinao do volume, a partir de dimenses lineares. Estudos apontam que os valores estimados da biomassa de rotferos podem variar de acordo com as metodologias de amostragem, preservao dos indivduos, caractersticas limnolgicas dos ambientes e genotpicas dos indivduos, predao, disponibilidade de alimento, alm da sazonalidade. Todos esses fatores evidenciam a necessidade de se estimar a biomassa ao invs da utilizao de equaes j descritas na literatura, bem como a importncia de se descrever detalhadamente a metodologia utilizada em cada amostragem, e algumas caractersticas limnolgicas dos ambientes estudados. Abstract in spanish La biomasa de una comunidad acutica provee informacin cuantitativa de la materia orgnica disponible en los diferentes niveles trficos. Las dificultades metodologas en la estimacin de la biomasa zooplanctnica explican los pocos estudios existentes, principalmente en Brasil. Se describen los m [...] todos ms utilizados en la estimacin de la biomasa de rotferos, se analizan sus ventajas y desventajas, se comparan los resultados obtenidos con cada tcnica, y se discuten algunos factores que influyen en su biomasa. El mtodo ms utilizado es la determinacin del biovolumen, obtenido a partir de las dimensiones lineales de los rotferos. La mayor parte de los estudios sugieren que la biomasa de rotferos vara de acuerdo con los mtodos de muestreo, la conservacin de los individuos, la depredacin y la disponibilidad de alimentos, adems de la estacionalidad. Todos estos factores evidencian la necesidad de estimar la biomasa en lugar de utilizar ecuaciones ya descritas en la literatura, as como la importancia de describir el mtodo utilizado en cada muestreo y algunas caractersticas limnolgicas de los ambientes estudiados. Abstract in english The biomass of an aquatic community provides quantitative information from available organic matter in different trophic levels. The methodological difficulties in estimating zooplankton biomass explain the scarcity of existing studies, particularly in Brazil. The most used methodologies for rotifer [...] biomass estimation are described and their advantages and disadvantages analyzed. Results obtained with the different techniques are compared and some factors influencing the biomass are discussed. The most commonly used methodology is the biovolume, calculated from rotifer linear dimensions. Studies point out that rotifers biomass vary according to sampling methodologies, individual preservation, environments limnological characteristics, individual genotypical characteristics, predation, food resource availability and seasonality. All these factors emphasize the importance of estimating biomass instead of using equations already described in the literature, as well as the importance to describe in detail the methodology employed in each sampling and some limnological features of the studied environments.

  17. Nanometer scale electronic reconstruction at the interface between LaVO3 and LaVO4

    OpenAIRE

    Kourkoutis, L. Fitting; Hotta, Y.; Susaki, T.; Hwang, H. Y.; Muller, D. A.

    2007-01-01

    Electrons at interfaces, driven to minimize their free energy, are distributed differently than in bulk. This can be dramatic at interfaces involving heterovalent compounds. Here we profile an abrupt interface between V 3d2 LaVO3 and V 3d0 LaVO4 using electron energy loss spectroscopy. Although no bulk phase of LaVOx with a V 3d1 configuration exists, we find a nanometer-wide region of V 3d1 at the LaVO3/LaVO4 interface, rather than a mixture of V 3d0 and V 3d2. The two-dime...

  18. CONCENTRACIN DE CARBONO EN LA BIOMASA AREA DEL MATORRAL ESPINOSO TAMAULIPECO

    Directory of Open Access Journals (Sweden)

    Jos I. Yerena-Yamallel

    2011-01-01

    Full Text Available Se determin la concentracin de carbono por unidad de biomasa base peso seco de 10 especies del matorral espinoso tamaulipeco y para cada uno de sus componentes (tallo, ramas, ramillas, hojas y corteza. La concentracin de carbono expresado como porcentaje de la biomasa, se hizo con el equipo Solids TOC Analyzer, que determina la concentracin de carbono en muestras slidas a travs de combustin completa. Mediante un ANAVA no se encontraron diferencias en la concentracin promedio de carbono de las especies (P>0.05; esta concentracin vari de 44.25 a 47.08 % con una media general de 45.41.32 %; Cordia boissieri (44.251.52 % y Acacia farnesiana (44.521.37 % son las especies que resultaron con los valores de concentracin de carbono menores, y Forestiera angustifolia (47.081.27 % con el ms alto. El componente corteza de Cordia boissieri obtuvo el menor porcentaje de concentracin de carbono (39.620.70 %, y las hojas de Acacia schaffneri el mayor (50.141.21 %; la interaccin de ambos factores result significativa (P<0.0001.

  19. El cultivo y el agua de riego sobre el carbono de la biomasa microbiana

    Scientific Electronic Library Online (English)

    Magaly, Ruiz; Jorge, Paolini.

    2004-04-01

    Full Text Available En este estudio se determin el carbono de la biomasa microbiana en ocho suelos cultivados con caa de azcar y banano, regados con aguas de distinto origen (residuales, de pozo, de lago), y en dos suelos bajo vegetacin natural (suelos testigo), localizados todos en la Cuenca del Lago de Valencia. [...] El carbono de la biomasa microbiana (C-BM) se determin por el mtodo de la respiracin inducida por sustrato. Los valores obtenidos variaron entre 206 y 1.553 g C-BM g-1 suelo, siendo ms altos en los suelos testigos y en los suelos lacustrinos sembrados con caa de azcar bajo riego con aguas residuales industriales y domsticas. Los valores del C-BM resultaron superiores en los suelos bajo banano (P Abstract in english In the present study, soil microbial biomass carbon (MBC) was determined in eight soils located in the Valencia Lake basin, cultivated with sugarcane or banana and irrigated with waters of different composition or origin (waste-, ground- and lake-water), and in two soils under natural vegetation (co [...] ntrol soils). MBC was estimated by substrate induced respiration method. MBC varied between 206 and 1.553 g microbial C g-1 soil. Highest values occurred in control soils and in the lacustrine soil cultivated with sugar cane and irrigated with waste waters. The values of MBC were higher in the alluvial soils cultivated with sugarcane than in the alluvial soils cultivated with banana (P

  20. Control de una planta prototipo de gasificacin de biomasa mediante redes neuronales

    Directory of Open Access Journals (Sweden)

    Carlos A. Forero Nez

    2013-01-01

    Full Text Available Los sistemas de gasificacin de Biomasa son una alternativa para emplear residuos agroindustriales y generar un combustible ga- seoso; sin embargo, estos procesos no lineales se ven afectados por las caractersticas tpicas del material y por la variacin en las temperaturas al interior del equipo, por lo tanto se requieren sistemas de control para alcanzar estados estables en el tiempo. Este trabajo analiza el desempeo de un control mediante redes neuronales aplicado a un gasificador de lecho fijo corriente descenden- te cuando se emplean cascaras de coco o cuesco de palma. Los resultados indican que el uso del sistema de control en el equipo, alimentado con cascaras de coco, permite aumentar las temperaturas en el reactor de 600C a 800C en la zona de inyeccin, superando as el problema derivado de la baja transferencia de energa por conduccin a travs del sistema. Cuando se emplea el control en la gasificacin de cuesco, la temperatura promedio se mantuvo constante en 790C, el CO presente en el gas estuvo alrededor de 10% mientras que el CO2 disminuy a 4%. La aplicacin de un sistema de control mediante redes neuronales es una gran alternativa puesto que se puede entrenar para cada tipo de biomasa mejorando la estabilidad del sistema y produciendo un gas de sntesis con menor contenido de CO2. Esto para un pas con gran diversidad de recursos agroindustriales abre la posibilidad de usar estos subproductos en la generacin de energa a partir de fuentes renovables.

  1. BIOMASA, PROLINA Y PARMETROS NITROGENADOS EN PLNTULAS DE NOGAL BAJO ESTRS HDRICO Y FERTILIZACIN NITROGENADA

    Directory of Open Access Journals (Sweden)

    Guadalupe Alejandra de la O-Quezada

    2011-01-01

    Full Text Available Se realiz un estudio cuyo objetivo fue medir la respuesta de los procesos fisiolgicos bajo las condiciones de estrs hdrico y concentracin de nitrgeno (N en plantas de nogal pecanero [Carya illinoinensis (Wangenh C. Koch]. El experimento consisti en la siembra, crecimiento y desarrollo de plantas a partir de semillas de nogal pecanero Western Schley; las cuales fueron sometidas a diferentes manejos: aportacin de riego y N, aportacin de riego sin N, estrs hdrico y adicin de N y finalmente bajo estrs hdrico y ausencia de N. Fueron evaluadas las siguientes variables: altura de planta, dimetro de tronco, concentracin de clorofila (unidades SPAD y metanol, nmero de hojas e ndice de rea foliar, prolina y biomasa. Los resultados demostraron que, las plntulas con aportacin de N y estrs hdrico redujeron la concentracin de Nt y N-NO3 - en 21.73 y 61.84 % respectivamente, rea foliar y dimetro de tronco en un 53.4 y 36.5 %, respectivamente, incrementndose el contenido de prolina en 39.41 %. Con riego y en ausencia de N se disminuy el contenido de clorofila en 20 % y la biomasa de tallo en 58.34 %, finalmente el contenido relativo de agua (CRA de tallo y raz decreci en 61.54 y 60.17 % respectivamente.

  2. BIOMASA Y RENDIMIENTO DE FRIJOL CON POTENCIAL EJOTERO EN UNICULTIVO Y ASOCIADO CON GIRASOL

    Directory of Open Access Journals (Sweden)

    J. Garduo-Gonzlez

    2009-01-01

    Full Text Available El objetivo del presente estudio fue estimar la produccin de biomasa, rendimiento y algunos de sus componentes de dos cultivares de frijol (Phaseolus vulgaris L. con potencial ejotero ('Acerado' y 'Criollo', en unicultivo y asociado con dos cultivares de girasol (Helianthus annuus L. ('Sunbright' y 'Victoria'. El estudio se realiz durante el ciclo primavera verano 2006 bajo condiciones de temporal en Tenancingo, Mx. Las variables evaluadas fueron: ndice de rea foliar (IAF, tasa de asimilacin neta (TAN, biomasa total (BT, dimetro de vaina (DV, longitud de vaina (LV, nmero de vainasm-2 (NV y rendimiento de vainam-2 (RV; las cuales fueron analizadas en arreglo factorial, bajo un diseo de bloques completos al azar con cuatro repeticiones. Para estimar el grado de asociacin, entre las variables estudiadas y el rendimiento de vainas, se realiz un anlisis de correlacin lineal simple. En el factor cultivares se detectaron diferencias estadsticas significativas para la TAN y DV; para el factor sistemas de siembra hubo diferencias significativas para BT, DV, NV y RV. La interaccin cultivares * sistema de siembra fue significativa en todas las variables, excepto en la TAN. En ese sentido, las asociaciones 'Criollo' + 'Sunbright', 'Acerado' + 'Victoria' y 'Acerado' en unicultivo, presentaron el mayor RV. Las variables IAF, BT y NV se correlacionaron positiva y significativamente con el rendimiento de vaina. Los resultados indican que 'Criollo' y 'Acerado', asociados con 'Sunbright' y 'Victoria', respectivamente, responden positivamente a la asociacin, constituyendo una buena opcin para los productores de la regin de Tenancingo, Mxico.

  3. REMOCIN DE PLOMO Y NQUEL EN SOLUCIONES ACUOSAS USANDO BIOMASAS LIGNOCELULSICAS: UNA REVISIN

    Directory of Open Access Journals (Sweden)

    Edgar Quiones

    2013-12-01

    Full Text Available En la presente revisin, se identifican los bioadsorbentes extrados de biomasas residuales utilizadas en la remocin de dos metales pesados, que presenta una amplia toxicidad para el ambiente: plomo y nquel. Se evala la capacidad de remocin de los mismos, destacando aquellos en los que se han obtenido altos porcentajes de remocin, mostrando la cintica aplicada en estos experimentos. Se encontr, que los bioadsorbentes ms usados incluyen residuos de madera, cscaras de frutos secos, residuos de cereales y ctricos. Para la remocin de plomo (II, el bagazo de caa de azcar, con una capacidad de remocin de 333mg/g y para el nquel (II, la corteza de Acacia, con una capacidad de remocin de 294,1mg/g, han sido los bioadsorbentes con mayor eficiencia de remocin. Se encuentra que, en la mayora de los experimentos, la cintica del proceso de adsorcin es regida por la ecuacin cintica de pseudo-segundo orden. Se recomienda el diseo de plantas piloto para la remocin de iones metlicos con las biomasas que mostraron mayor capacidad de adsorcin, con el fin de que estos procesos puedan ser llevados a escala industrial.

  4. Anlisis Exergtico de la Gasificacin de Biomasa / Exergy Analysis of Biomass Gasification

    Scientific Electronic Library Online (English)

    Jorge M, Mendoza; Antonio J, Bula; Rafael D, Gmez; Lesmes A, Corredor.

    Full Text Available El objetivo de este estudio fue realizar el anlisis exergtico de la gasificacin de biomasa residual con la finalidad de obtener energa til. Se desarroll un modelo para la gasificacin de biomasa basado en el equilibrio qumico de las reacciones. Este modelo permite predecir la evolucin de la [...] composicin del gas de sntesis en funcin de la temperatura, las presiones y la composicin elemental de los residuos del proceso de extraccin de aceite de palma y orujo de lavado de uva (hidrogeno, oxigeno, carbono y nitrgeno), como tambin hacer un anlisis exergtico. Se encontr que independiente del agente gasificante, la concentracin de monxido de carbono e hidrgeno tienden a incrementar significativamente a altas presiones y elevadas temperaturas. Adems, se muestra que la eficiencia exergtica incrementa con la temperatura y disminuye con el aumento de la relacin aire/combustible. Abstract in english This paper shows the exergy analysis applied to the gasification process of residual biomass with the purpose of obtaining useful energy. A model for the biomass gasification based on chemical equilibrium of the reactions is proposed. The model allows predicting the syngas composition as a function [...] of temperature, pressure and ultimate analysis of palm oil and grapevine pruning waste (determining hydrogen, oxygen, carbon and nitrogen). It was found that the carbon monoxide and hydrogen concentration significantly increase at high pressure and temperature independently of the gasifying agent. Furthermore, it was also noticed that the exergy efficiency increases as temperature increases, and decreases as the relative fuel/air ratio increases.

  5. Evolution of the spectral weight in the Mott-Hubbard series SrVO3-CaVO3-LaVO3-YVO3

    International Nuclear Information System (INIS)

    The Mott-Hubbard series SrVO3-CaVO3-LaVO3-YVO3 present a distinct metal-insulator transition. The microscopic origin of this transition can be related to the correlation effects in the electronic structure. The valence band photoemission results show very interesting trends across these Mott-Hubbard series. These results suggest that the O 2p states play an important role in the Mott-Hubbard transition. Some of the changes in the spectra are unexpected and cannot be explained by the current Mott-Hubbard theories (author)

  6. Efeito do tempo de intervalo da amostra ventilatria na variabilidade do consumo mximo de oxignio (VO2 mx) em jogadores de futebol profissional / Effect of time intervals of ventilatory sampling in the variability of maximum oxygen uptake in professional soccer players

    Scientific Electronic Library Online (English)

    Paulo Roberto Santos, Silva; Angela, Romano; Ana Maria, Visconti; Alberto Alves de Azevedo, Teixeira; Carla Dal Maso Nunes, Roxo; Gilberto da Silva, Machado; Luciana Collet Winther, Rebello; Jorge Mendes de, Sousa.

    1999-04-01

    Full Text Available O propsito deste estudo foi verificar, em futebolistas profissionais, o impacto de sete intervalos de tempo sobre a varivel fisiolgica consumo mximo de oxignio (VO2 mx). Dezoito jogadores de futebol com mdia de idade de 24 4 anos (18-31), peso de 72,5 5,9kg (62-83) e estatura de 176,5 7 [...] ,0cm (164-188) foram submetidos a teste ergomtrico mximo em esteira rolante, utilizando-se protocolo escalonado contnuo. A resposta de freqncia cardaca (FC) foi registrada por meio de um eletrocardigrafo computadorizado de 12 derivaes simultneas. A ventilao pulmonar (V E), o consumo de oxignio (VO2), a produo de dixido de carbono (VCO2) e a razo de troca respiratria (RER) foram calculadas a partir de valores medidos por um sistema espiromtrico computadorizado. Os resultados deste estudo demonstraram que houve variabilidade significante do VO2 mx (p Abstract in english The purpose of this investigation was to verify the impact of seven ventilatory time intervals on the maximum oxygen uptake (VO2 max) in professional soccer players. Eighteen male soccer players aged 24.4 4 (18-31), weight 72.5 5.9 kg (62-83) and height 176.5 7 cm (164-188) were submitted to a [...] maximum exercise test on treadmill, using the continuous protocol. The heart rate response was recorded by means of computerized ECG with 12 leads, simultaneously. The respiratory exchange ratio, carbon dioxide production, oxygen uptake and pulmonary ventilation were calculated by means of the spirometric computerized system. The results of this study demonstrated that there was significant variability (p

  7. Hydrothermal synthesis and electrochemical characterization of VO{sub 2} (B) with controlled crystal structures

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Wentao; Ni Juan [Key Laboratory of Polar Materials and Devices (Ministry of Education of China), Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China); Yu Ke, E-mail: yk5188@263.net [Key Laboratory of Polar Materials and Devices (Ministry of Education of China), Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China); Zhu Ziqiang [Key Laboratory of Polar Materials and Devices (Ministry of Education of China), Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China)

    2011-02-01

    Three different VO{sub 2} (B) nanostructures, including urchin-like VO{sub 2} (B), VO{sub 2} (B) honeycombs and VO{sub 2} (B) nanorods have been successfully fabricated through hydrothermal process by adjusting the concentrations of the oxalic acid. The microstructure and morphology of the VO{sub 2} nanostructures were evaluated by using X-ray diffraction and scanning and transmission electron microscopies. Electrochemical properties measurements of urchin-like VO{sub 2} (B) and VO{sub 2} (B) honeycombs showed excellent cycling performance, especially the urchin-like VO{sub 2} (B) exhibited higher discharge capacity and better capacity retention.

  8. New open-framework in the uranyl vanadates A3(UO2)7(VO4)5O (A=Li, Ag) with intergrowth structure between A(UO2)4(VO4)3 and A2(UO2)3(VO4)2O

    International Nuclear Information System (INIS)

    New uranyl vanadates A3(UO2)7(VO4)5O (M=Li (1), Na (2), Ag (3)) have been synthesized by solid-state reaction and their structures determined from single-crystal X-ray diffraction data for 1 and 3. The tetragonal structure results of an alternation of two types of sheets denoted S for ?2[UO2(VO4)2]4- and D for ?2[(UO2)2(VO4)3]5- built from UO6 square bipyramids and connected through VO4 tetrahedra to ?1[U(3)O5-U(4)O5]8- infinite chains of edge-shared U(3)O7 and U(4)O7 pentagonal bipyramids alternatively parallel to a- and b-axis to construct a three-dimensional uranyl vanadate arrangement. It is noticeable that similar ?[UO5]4- chains are connected only by S-type sheets in A2(UO2)3(VO4)2O and by D-type sheets in A(UO2)4(VO4)3, thus A3(UO2)7(VO4)5O appears as an intergrowth structure between the two previously reported series. The mobility of the monovalent ion in the mutually perpendicular channels created in the three-dimensional arrangement is correlated to the occupation rate of the sites and by the geometry of the different sites occupied by either Na, Ag or Li. Crystallographic data: 293 K, Bruker X8-APEX2 X-ray diffractometer equipped with a 4 K CCD detector, MoK?, ?=0.71073 A, tetragonal symmetry, space group P4-bar m2, Z=1, full-matrix least-squares refinement on the basis of F2; 1,a=7.2794(9) A, c=14.514(4) A, R1=0.021 and wR2=0.048 for 62 parameters with 782 independent reflections with I?2?(I); 3, a=7.2373(3) A, c=14.7973(15) A, R1=0.041 and wR2=0.085 for 60 parameters with 1066 independent reflections with I?2?(I). - Abstract: A view of the three-dimensional structure of Li3(UO2)7(VO4)5O. Display Omitted

  9. INFLUNCIA DO GNERO NOS TESTES DE VO2MX E RAST EM ATLETAS DE ATLETISMO

    Directory of Open Access Journals (Sweden)

    Ronaldo Nascimento Maciel

    2011-07-01

    Full Text Available A manuteno de nveis timos de potncia muscular e a recuperao rpida so imprescindveis para o bomdesempenho no atletismo. O objetivo do estudo foi de comparar entre os gneros a mdia dos escores deVO2mx e do RAST e correlacionar os nveis de VO2 mx e o ndice de fadiga com os nveis de potnciamxima e mdia. A amostra foi constituda de n=24 atletas com 16.32.51 anos, sendo n=12 do GneroMasculino (GM e n=12 do Gnero Feminino (GF. Considerou os nveis significativos p<0,05. Foramobtidos os seguintes resultados no RAST; Potncia Mxima (GM e (GF 434.6122.7 Watts e 293.866.2Watts (p=0.03; Potncia Mdia 367101.9 Watts; 226.653.0 Watts (p=0.02 e na Potncia Mnima302.580.2 Watts e 237.2206.6 Watts (p=0.00. Nos valores relativos, (GM e (GF a Potncia Mxima foide 7.051.70 Watts/Kg e 5.491.22 Watts/Kg (p=0.02; Potncia Mdia 5.951.36 Watts/Kg e 4.220.99Watts/Kg (p=0,01; Potncia Mnima 4.891.07 Watts/Kg e 3.061.27 Watts/Kg (p=0,01. No VO2mx o(GM (GF obtiveram 41.16.2 ml.(kg.min- e 32.66.4 ml.(kg.min- (p=0.00. Encontrou uma correlaono VO2mx e Potncia Mxima (r= 0.6744 / p= 0.01, VO2mx e a Potncia Mdia (r= 0.8227 / p= 0.00,Potncia Mxima e o ndice de Fadiga (r= 0.7326 / p= 0.00. Conclui-se que as diferenas significativasencontradas nos valores de potncias mxima, mdia e mnima (Watts (Watts/Kg, ratificam estudosanteriores. A correlao do VO2mx e a potncia mdia, apontam para uma possvel relao direta, fato que,se confirmado, pode ajudar a entender resultados de atletas de vrios nveis.

  10. RELACIN ENTRE LA BIOMASA Y ALGUNAS CARACTERSTICAS MORFOLGICAS DE LAS BROMELIAS FITOTELMATAS DE UN BOSQUE ALTO ANDINO COLOMBIANO

    Directory of Open Access Journals (Sweden)

    Isaza Carolina

    2009-06-01

    Full Text Available Se evaluaron algunas caractersticas morfolgicas para seis especies de bromelias fitotelmata (Guzmania gloriosa, Racinaea tetrantha, Tillandsia biflora, T. complanata, T. fendleri y T. turneri con el fin de establecer cuales caractersticas podran utilizarse como estimadores indirectos de la biomasa total de la planta. El estudio se realiz en un bosque alto andino de la Sabana de Bogot, Colombia, ubicado a 2900 m de altitud. Para cada especie se recolectaron entre 32 y 64 individuos en diferentes estadios de crecimiento, a cada uno de los cuales se le registr: 1 el nmero de hojas por roseta; 2 el permetro de la base de la roseta; 3 la cobertura de la planta; 4 el largo de la lmina foliar; 5 la altura de la roseta; y 6 la biomasa total. Los resultados de la prueba Wilcoxon muestran que la cobertura fue la variable que ms se relacion con la biomasa. Una prueba de ajuste de curva mostr que la lnea recta es la que ms explica la relacin entre la cobertura y la biomasa, permitiendo hacer estimaciones a partir de la ecuacin sin ser necesario un muestreo destructivo.

  11. Phase-Dependent Enhancement of the Green-Emitting Upconversion Fluorescence in LaVO4:Yb(3+), Er(3+).

    Science.gov (United States)

    Zhang, Feng; Li, Guoqiang; Zhang, Weifeng; Yan, Yu Li

    2015-08-01

    The phase-dependent upconversion luminescence properties of LaVO4:Er(3+) were studied to provide new insights into the design of new upconversion materials with high efficiency. Er(3+)-, Yb(3+)/Er(3+)-doped t-LaVO4 microcrystals were successfully synthesized by the disodium ethylenediaminetetraacetic acid (Na2EDTA)-assisted hydrothermal method. X-ray diffraction (XRD), inductively coupled plasma optical emission spectrometer (ICP-OES), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, luminescence spectroscopy, and thermogravimetric analysis (TGA) were used to characterize the samples. The results indicated that t-LaVO4 presents sheaf-like morphology, and the possible formation mechanism for these sheaves was proposed on the basis of time-dependent experiments. Furthermore, the phase-dependence (i.e., monoclinic- and tetragonal-type) upconversion luminescence properties were systematically studied, and the upconversion mechanisms were proposed according to spectral, pump power, and the concentration of Yb(3+) dependence analyses. It is worthwhile pointing out that the Er(3+)-doped t-LaVO4 exhibits a brighter green emission, which is approximately 10 times that of m-LaVO4:Er(3+) using a continuous 980 nm laser diode as the excitation source. This remarkable improvement was rationally analyzed on the basis of the composition, crystal structures, Raman spectra, morphology, and size. The comparative experiments suggest that the local structure of Er(3+) was considered as an important reason for the higher fluorescence intensity of t-LaVO4:Er(3+), which was also confirmed by the results of density functional theory (DFT) calculations. PMID:26203901

  12. Revisin sobre la corrosin de tubos sobrecalentadores en plantas de biomasa

    Directory of Open Access Journals (Sweden)

    Berlanga-Labari, C.

    2006-08-01

    Full Text Available The design of new biomass-fired power plants with increased steam temperature raises concerns of high-temperature corrosion. The high potassium and chlorine contents in many biomasses, specially in wheat straw, are potentially harmful elements with regard to corrosion. Chlorine may cause accelerated corrosion resulting in increased oxidation, metal wastage, internal attack, void formations, and loose non-adherent scales. The most severe corrosion problems in biomass-fired systems are expected to occur due to Cl-rich deposits formed on superheater tubes. In the first part of this revision the corrosion mechanism proposed are described in function of the conditions and compounds involved. The second part is focused on the behaviour of the materials tested so far in the boiler and in the laboratory. First the traditional commercial alloys are studied and secondly the new alloys and the coatings

    En el diseo de plantas de biomasa es muy importante tener en cuenta la temperatura del vapor para no tener problemas de corrosin. Esto, es debido al alto contenido de potasio y cloro que tienen la mayora de los biocombustibles y, en especial, la paja de cereal. El objetivo de esta revisin es condensar el conocimiento actual sobre la corrosin de los sobrecalentadores a altas temperaturas provocada por compuestos clorados en plantas de biomasa. El cloro puede causar corrosin acelerada debido a la prdida de metal del sobrecalentador, ataque interno y formacin de capas de xidos no adherentes. Los problemas de corrosin ms severos en una caldera de biomasa se producen en los depsitos formados sobre los tubos sobrecalentadores. En la primera parte de esta revisin, se describen los mecanismos de corrosin propuestos en funcin de las condiciones de trabajo predominantes en la caldera. La segunda parte, se centra en revisar los estudios realizados para comprobar el comportamiento de los materiales mediante ensayos realizados en la caldera y en el laboratorio. En primer lugar, se describen las investigaciones realizadas sobre aleaciones convencionales y despus las realizadas sobre las aleaciones desarrolladas en los ltimos aos y recubrimientos.

  13. Estimacin de la biomasa area de seis leguminosas leosas del Chaco rido (Argentina)

    Scientific Electronic Library Online (English)

    Mara del Rosario, Iglesias; Alicia Hayde, Barchuk.

    2010-04-01

    Full Text Available La posibilidad de contar con estimaciones confiables de la biomasa area de la vegetacin leosa resulta imprescindible para el manejo productivo, la conservacin o la restauracin de los ecosistemas de bosque. Sin embargo, no siempre se dispone de tcnicas relativamente sencillas y no destructivas. [...] Este trabajo presenta modelos de regresin para estimar la biomasa area total de seis especies arbustivas y arbreas de la familia Fabaceae, nativas del Chaco rido (Prosopis flexuosa, Geoffroea decorticans, Cercidium praecox, Acacia furcatispina, Mimoziganthus carinatus y Prosopis torquata). Los modelos incluyeron distintas combinaciones del dimetro a la base (DAB) y la altura de los individuos. Todos ellos predijeron aceptablemente la biomasa por especie, si bien el de regresin lineal que utiliza el DAB como variable independiente present el mejor ajuste. Las especies fueron agrupadas segn sus rasgos comunes en: monopdicas de madera dura, multitallares de madera extremadamente pesada, monopdica de madera excesivamente pesada y monopdica y multitallar de madera extremadamente pesada y para cada uno de los grupos se gener una ecuacin. Abstract in english Reliable estimates of biomass for the vegetation of the Arid Chaco forest is critical for its management, conservation or restoration. However, simple and non destructive techniques are not largely available. This study provides regression models aimed at estimating the aerial biomass of native shru [...] b and tree species from the Arid Chaco, belonging to the Fabaceae family (Prosopis flexuosa, Geoffroea decorticans, Cercidium praecox, Acacia furcatispina, Mimoziganthus carinatus and Prosopis torquata). An additional objective was to explore the feasibility of using a single equation for several species. The wood density differed significantly between species. Linear and nonlinear regression models of aerial biomass were adjusted for species, with different combinations of base diameter (DAB) and height as independent variables. The models properly predicted the biomass by species, the most appropriate being the linear regression model using DAB as an independent variable. To establish differences in the behavior of species and, more precisely, in the ratio between total dry weight and DAB, the slope homogeneity was analyzed using a regression model with auxiliary variables. Taking into account the results obtained and the basic wood density and morphological growth structure, four groups of species have been postulated, and it was feasible to apply a single equation per group. The proposed groups are: (1) monopodial hardwood (Geoffroea decorticans and Cercidium praecox), (2) multi-stem shrubs of extremely heavy wood (Acacia furcatispina and Mimoziganthus carinatus), (3) monopodial of very heavy wood (Prosopis flexuosa) and (4) monopodial and multi-stem of extremely heavy wood (Prosopis torquata).

  14. Produccion de Biomasa de Scenedesmus Obliquus en diferentes medios de cultivo.

    Directory of Open Access Journals (Sweden)

    V. Martínez

    2005-01-01

    Full Text Available Los nutrientes son factores fundamentales que afectan el rendimiento de los cultivos de microalgas, de ahí la importancia de llevar a cabo estudios a escala de laboratorio con cepas de interés científico y comercial. El objetivo del trabajo fue investigar la producción de biomasa de Scenedesmus obliquus en diferentes medios de cultivo. Se utilizaron dos reactores tipo columnas de 2 L de capacidad empleando medio Extracto de Suelo, y medio Albañal Sintético respectivamente, a los cuales se les adicionó el inóculo del cultivo (1%, en la fase logarítmica de crecimiento. Para mantener agitado y homogéneo el sistema, se suministró aire a razón de 100 L/h, que fue medido con un regulador de flujo y se colocaron en un local cuya temperatura media era de 29,7 o C. Los reactores trabajaron en modo discontinuo (batch. Se mantuvieron con un régimen de luz/oscuridad de 8/16 horas durante 18 días. Para seguir el comportamiento del cultivo se determinó la Densidad óptica, la clorofila a, los sólidos suspendidos volátiles, se midió el pH y la producción de biomasa en el sistema. La velocidad de crecimiento específico fue ¿ = 0,16 d-1 para el cultivo en el medio Agar extracto de suelo y ¿ = 0,33 d-1 para el cultivo en medio Albañal sintético. El tiempo de duplicación fue de 4,33 d'-1 para el cultivo en medio AES y 2,10 d-1 para el medio de Albañal Sintético. Se alcanzaron los valores más altos en la producción de biomasa en el medio Albañal, lo que demostró un mejor desarrollo de la microalga investigada en este medio.

  15. Proceso de gasificacin de biomasa: una revisin de estudios terico- experimentales / Biomass gasification process: theoretical and experimental studies a review

    Scientific Electronic Library Online (English)

    Juan, Prez; David, Borge; John, Agudelo.

    2010-03-01

    Full Text Available La situacin energtica y medioambiental mundial hace que la generacin de energa mediante sistemas basados en energas renovables tome cada vez una mayor relevancia. Estos sistemas tienen una doble ventaja ya que posibilitan la diversificacin energtica y reducen la dependencia del petrleo a la [...] vez que se disminuyen las emisiones globales de CO2. La biomasa es uno de los recursos energticos con mayor potencial tanto en pases desarrollados como emergentes pero sigue sin sufrir el desarrollo esperado. La gasificacin de biomasa es uno de los sistemas con gran potencial ya que permite la generacin tanto de energa trmica como elctrica, mediante tecnologas de bajo costo como los gasificadores de lecho fijo (potencias medias- bajas), o reactores de lecho fluidizado con tecnologa ms exigente y con mayor capacidad de generacin. La transformacin de la biomasa en un combustible gaseoso, aprovechable en motores de combustin interna alternativos o en turbinas de gas como combustible, exige que la biomasa atraviese varios procesos termoqumicos, compuestos por reacciones endotrmicas (secado, devolatilizacin y reduccin) y exotrmicas (oxidacin de voltiles y carbn). La seleccin de un gasificador requiere conocer las propiedades de la biomasa, mientras que el diseo del mismo exige conocer el fenmeno termoqumico por completo. El objetivo de este trabajo es presentar una revisin actualizada de los diferentes planteamientos tanto tericos como experimentales desarrollados para estudiar el proceso de gasificacin de biomasa, tanto en lecho fijo como en lecho fluidizado, con miras a disear gasificadores de biomasa. Abstract in english Each day the energy systems relying on renewable resources are more relevant in the world energy politics due to the fossil energy and environmental crisis. These systems increase energy resources of countries, reduce the oil dependency, and diminish CO2 global emissions. Biomass is one of the renew [...] able resources with higher potential in developing and developed countries. Biomass gasification has huge possibilities to be developed. Such as fixed bed gasifiers, or fluidized bed reactors with more technology demanding and more power capacity. Biomass transformation in a gaseous fuel to be used in a reciprocating internal combustion engine or gas turbines requires that biomass passes through several thermochemical stages. Endothermic reactions (drying, pyrolysis and reduction) and exothermic process (volatiles and carbon oxidation). To select a specific gasifier it is necessary to know biomass properties (chemical and physical), whereas to design a reactor it is necessary to know and understand the complete phenomena. The aim of this work is to show an actualized review about different theoretical and experimental approaches to study biomass gaification process in fixed and fluidized bed reactors in order to design biomass gasifiers.

  16. Producción de biomasa de Saccharomyces cerevisiae y Candida utilis usando residuos de pulpa de Coffea arabica L

    Directory of Open Access Journals (Sweden)

    María J Gualtieri A

    2007-12-01

    Full Text Available Los avances en biotecnología industrial ofrecen oportunidades potenciales para la utilización económica de residuos agro-industriales tales como la pulpa de café, material mucilaginoso, fibroso (producto secundario obtenido durante el proceso húmedo o seco del beneficio de las cerezas de café. El propósito de este trabajo fue utilizar los residuos de la pulpa de café, rico en materia orgánica, como sustrato para la producción de biomasa de levaduras por procesos de fermentación aeróbica. Los residuos de café se sometieron a hidrólisis con una solución de ácido sulfúrico al 2%, en una relación 10:1 (líquido:sólido, con un tamaño de partícula ≤ 2 mm., operando a presión atmosférica, ebullición a reflujo, durante 4 horas. El extracto ácido se filtró y se ajustó a pH 4,5 y luego se esterilizó a 120 ºC por 15 minutos. La fermentación se realizó con Saccharomyces cerevisiae y Candida utilis, medio de producción extracto de café enriquecido con sales nutritivas. Se formularon diferentes medios de producción (1,2,3 y 4, siendo el N°3, enriquecido con extracto de café hidrolizado, 1L; urea, 3g/L; fosfato ácido de potasio, 2g/L; extracto de malta, 1,3g/L y melaza, 30g/L, el cual aportó los mejores resultados. El tiempo total de fermentación fue de 8 horas. Se obtuvo 10g/L de biomasa con un incremento proteico de 7,39 a 42,5%. Se puede concluir que la pulpa de café constituye un sustrato adecuado para obtener biomasa o proteína unicelular, que podría ser destinada como suplemento en formulaciones para alimentación animalThe advances in industrial biotechnology offer potential opportunities for the economic use of agro-industrial remainders such as the coffee pulp, mucilagenous, fibrous material (secondary product obtained during the humid or dry process of the benefit of the coffee cherries. The intention of this work was to use the remainders of the pulp of coffee, rich in organic matter, like substrate for the production of biomass of leavenings by processes of aerobic fermentation. The coffee remainders were put under hydrolysis with a sulfuric acid solution to 2%, in a 10:1 relation (liquid: solid, with a size of particle ≤ 2 mm, operating to atmospheric pressure, boiling to ebb tide, during 4 hours. The acid extract filtered and it adjusted to pH 4,5 and then it sterilize to 120 ºC by 15 minutes. The fermentation was made with Saccharomyces cerevisiae and Candida utilis, the production means: extract of coffee enriched with nutritious salts. Different means from production were formulated (1,2,3 and 4, being the N°3, enriched with extract of hydrolyzed coffee, 1L; urea, 3g/L; acid potassium phosphate, 2g/L; extract of Malta, 1,3g/L and molasses, 30g/L, which contributed the best results. The total time of fermentation was of 8 hours. 10g/L of biomass with a protein increase from 7.39 to 42.5% was obtained. It is possible to be concluded that the coffee pulp constitutes an suitable substrate to obtain biomass or unicellular protein, that could be destined like supplement in formulations for feeding animal

  17. The Effect of Habitual Smoking on VO2max

    Science.gov (United States)

    Wier, Larry T.; Suminski, Richard R.; Poston, Walker S.; Randles, Anthony M.; Arenare, Brian; Jackson, Andrew S.

    2008-01-01

    VO2max is associated with many factors, including age, gender, physical activity, and body composition. It is popularly believed that habitual smoking lowers aerobic fitness. PURPOSE: to determine the effect of habitual smoking on VO2max after controlling for age, gender, activity and BMI. METHODS: 2374 men and 375 women employed at the NASA/Johnson Space Center were measured for VO2max by indirect calorimetry (RER>=1.1), activity by the 11 point (0-10) NASA Physical Activity Status Scale (PASS), BMI and smoking pack-yrs (packs day*y of smoking). Age was recorded in years and gender was coded as M=1, W=0. Pack.y was made a categorical variable consisting of four levels as follows: Never Smoked (0), Light (1-10), Regular (11-20), Heavy (>20). Group differences were verified by ANOVA. A General Linear Models (GLM) was used to develop two models to examine the relationship of smoking behavior on VO2max. GLM #1(without smoking) determined the combined effects of age, gender, PASS and BMI on VO2max. GLM #2 (with smoking) determined the added effects of smoking (pack.y groupings) on VO2max after controlling for age, gender, PASS and BMI. Constant errors (CE) were calculated to compare the accuracy of the two models for estimating the VO2max of the smoking subgroups. RESULTS: ANOVA affirmed the mean VO2max of each pack.y grouping decreased significantly (psmoking exposure increased. GLM #1 showed that age, gender, PASS and BMI were independently related with VO2max (R2 = 0.642, SEE = 4.90, pSmoked, the effects on VO2max from Light and Regular smoking habits were -0.83 and -0.85 ml.kg- 1.min-1 respectively (peffect of Heavy smoking on VO2max was -2.56 ml.kg- 1.min-1 (psmoking group in GLM #2 was smaller than the CE s of the smoking group counterparts in GLM #1. CONCLUSIONS: After accounting for the effects of gender, age, PASS and BMI the effect of habitual smoking on reducing VO2max is minimal, about 0.85 ml/kg/min, until the habit exceeds 20 pack.y at which point an additional decrease of 1.71 ml/kg/min is noted. Adding pack.y data improves the accuracy of predicting the VO2max of smokers.

  18. Bioadsorcin de Cadmio (II) en Solucin Acuosa por Biomasas Fngicas / Biosorption of Cadmium (II) in Aqueous Solutions by Fungal Biomass

    Scientific Electronic Library Online (English)

    Ismael, Acosta; Mara de Guadalupe, Moctezuma-Zrate; Juan F, Crdenas; Conrado, Gutirrez.

    Full Text Available Se determin la bioadsorcin de Cadmio (II) en solucin por la biomasa celular de quince hongos, por el mtodo colorimtrico de la ditizona. La biomasa de Mucor rouxii IM-80 fue ms eficiente en la remocin de Cadmio (II) en solucin (8.2 mg/g) seguida de M. rouxii mutante (7.1 mg/g), A. flavus I (5 [...] .9 mg/g) y Helminthosporium sp (5.4 mg/g). Para la biomasa de M. rouxii-IM-80, la mayor bioadsorcin fue a pH= 5.0-6.0, a 28C durante 40 horas con 1.0 mg/200 mL de concentracin inicial de Cadmio (II) y 80 mg/200 mL de biomasa celular. Se concluye que algunas biomasas fngicas remueven eficientemente Cadmio (II) en solucin y pueden utilizarse para descontaminar nichos acuticos contaminados con este metal Abstract in english The biosorption of dissolved Cadmium (II) using cellular biomass of 15 fungi, using a dithizone colorimetric method, was determined. The Mucor rouxii IM-80 biomass was more efficient in removing Cadmium (II) from solution (8.2 mg/g), followed by the M. rouxii mutant (7.1 mg/g), Aspergillus flavus I [...] (5.9 mg/g) and Helminthosporium sp (5.4 mg/g) biomasses. The highest biosorption for M. rouxii IM-80 was at pH 5.0-6.0, at 28C for 40 h employing 1.0 mg/200mL of Cadmium (II) as initial concentration, and 80 mg/200 mL of fungal biomass. It was concluded that some fungal biomass efficiently removed Cadmium (II) from solution and could be used for decontamination of aquatic habitats polluted with this metal

  19. COMPORTAMIENTO DE LA ACUMULACIN Y DISTRIBUCIN DE BIOMASA EN GENOTIPOS DE PAPA ESTABLECIDOS EN CONDICIONES DE SECANO

    Directory of Open Access Journals (Sweden)

    R. Mora-Aguilar

    2005-01-01

    Full Text Available El estudio se realiz durante el periodo de secano de 1996, en Metepec, Mxico, para determinar el comportamiento de la acumulacin y distribucin de biomasa en los diferentes rganos y en la planta completa de cinco genotipos de papa; stos fueron establecidos en surcos de 90 cm de anchura y 30 cm de distancia entre plantas de un slo tallo. Despus de la emergencia, a intervalos de 71 das, fueron cosechadas cinco plantas en competicin completa y disecadas la parte area (hojas, tallo principal y tallo de ramas y subterrnea (races, estolones, tubrculos y seccin enterrada del tallo principal. Posteriormente fueron puestas a secar en una estufa con aire forzado a 75 C por 72 h hasta alcanzar su peso seco constante. El comportamiento de la acumulacin y distribucin de biomasa hacia los diferentes rganos de la planta estuvo asociada, en la mayora de los casos, con el hbito de crecimiento de los genotipos: determinado en 'Alpha', 'Nortea' y 'C-771A11', o indeterminado en 'Puebla' y 'C-676014'. Las curvas de acumulacin fueron similares entre genotipos y su tendencia general se ajust a modelos de tipo logstico o polinomial. A partir de los 45 a 50 das despus la emergencia, la acumulacin de biomasa en la parte subterrnea y la planta completa fue casi paralela. La duracin de la etapa de tuberizacin afect la acumulacin de biomasa en los tubrculos de manera que los genotipos de ciclo intermedio, como 'Nortea' y 'C-676014', fueron ms eficientes (272 y 294 gplanta-1 que los precoces o tardos. Entre los rganos areos, las hojas acumularon ms biomasa (40-53 y 79-81 gplanta-1, independientemente del hbito de crecimiento de los genotipos.

  20. Integrating the IA2 Astronomical Archive in the VO: The VO-Dance Engine

    Science.gov (United States)

    Molinaro, M.; Laurino, O.; Smareglia, R.

    2012-09-01

    Virtual Observatory (VO) protocols and standards are getting mature and the astronomical community asks for astrophysical data to be easily reachable. This means data centers have to intensify their efforts to provide the data they manage not only through proprietary portals and services but also through interoperable resources developed on the basis of the IVOA (International Virtual Observatory Alliance) recommendations. Here we present the work and ideas developed at the IA2 (Italian Astronomical Archive) data center hosted by the INAF-OATs (Italian Institute for Astrophysics - Trieste Astronomical Observatory) to reach this goal. The core point is the development of an application that from existing DB and archive structures can translate their content to VO compliant resources: VO-Dance (written in Java). This application, in turn, relies on a database (potentially DBMS independent) to store the translation layer information of each resource and auxiliary content (UCDs, field names, authorizations, policies, etc.). The last token is an administrative interface (currently developed using the Django python framework) to allow the data center administrators to set up and maintain resources. This deployment, platform independent, with database and administrative interface highly customizable, means the package, when stable and easily distributable, can be also used by single astronomers or groups to set up their own resources from their public datasets.

  1. Synthesis of a new vanadyl(IV) complex with trehalose (TreVO): insulin-mimetic activities in osteoblast-like cells in culture.

    Science.gov (United States)

    Barrio, Daniel A; Williams, Patricia A M; Cortizo, Ana M; Etcheverry, Susana B

    2003-04-01

    Vanadium compounds show interesting biological and pharmacological properties. Some of them display insulin-mimetic effects and others produce anti-tumor actions. The bioactivity of vanadium is present in inorganic species like the vanadyl(IV) cation or vanadate(V) anion. Nevertheless, the development of new vanadium derivatives with organic ligands which improve the beneficial actions and decrease the toxic effects is of great interest. On the other hand, the mechanisms involved in vanadium bioactivity are still poorly understood. A new vanadium complex of the vanadyl(IV) cation with the disaccharide trehalose (TreVO), Na(6)[VO(Tre)(2)].4H(2)O, here reported, shows interesting insulin-mimetic properties in two osteoblast cell lines, a normal one (MC3T3E1) and a tumoral one (UMR106). The complex affected the proliferation of both cell lines in a different manner. On tumoral cells, TreVO caused a weak stimulation of growth at 5 microM but it inhibited cell proliferation in a dose-response manner between 50 and 100 microM. TreVO significantly inhibited UMR106 differentiation (15-25% of basal) in the range 5-100 microM. On normal osteoblasts, TreVO behaved as a mitogen at 5-25 microM. Different inhibitors of the MAPK pathway blocked this effect. At higher concentrations (75-100 microM), the complex was a weak inhibitor of the MC3T3E1 proliferation. Besides, TreVO enhanced glucose consumption by a mechanism independent of the PI3-kinase activation. In both cell lines, TreVO stimulated the ERK phosphorylation in a dose- and time-dependent manner. Different inhibitors (PD98059, wortmannin, vitamins C and E) partially decreased this effect, which was totally inhibited by their combination. These results suggest that TreVO could be a potential candidate for therapeutic treatments. PMID:12761667

  2. Synthesis, characterization and formation mechanism of metastable phase VO2(A) nanorods

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Pure phases of VO2(B) and VO2(A) were prepared by a facile hydrothermal method. • Belt-like particles prepared at 180 °C was indexed as monoclinic VO2(B) phase. • Rod-like particles prepared at 230 °C was indexed as tetragonal VO2(A) phase. • VO2(A) nanorods resulted from VO2(B) nanobelts by assembly and crystal adjustment. - Abstract: Pure phase VO2(A) nanorods were synthesized via the reduction of V2O5 by oxalic acid during the hydrothermal treatment. Two sets of samples were prepared by varying both system temperature and reaction time under a filling ratio of 0.40 for observing the formation and evolution of VO2(A) nanorods. Structures were characterized by X-ray diffraction, scanning and transmission electron microscopies, respectively. It was found that VO2(B) was firstly formed and then transformed into VO2(A) as the increasing system temperature or extending reaction time. An assembling and following crystal adjustment was proposed for explanation the formation process of VO2(A) from VO2(B). For VO2(A) nanorods, the phase transition temperature of 169.7 °C was higher than that of the VO2(A) bulk, it might be ascribed to the lower crystallinity or nonstoichiometry in VO2(A) nanorods. VO2 nanostructures with controllable phases and properties should find their promising applications in a single VO2 nanodevice

  3. ESTUDIOS TOXICOLOGICOS COMO HERRAMIENTA PARA EVALUAR EL DESEMPENO DE UN REACTOR ANAEROBIO DE BIOMASA INMOVILIZADA

    Directory of Open Access Journals (Sweden)

    TATIANA RODRIGUEZ CHAPARRO

    2010-01-01

    Full Text Available Los efluentes de la Industria de Papel y Celulosa son usualmente txicos y mutagnicos. Esa caracterstica se deriva principalmente por la presencia de compuestos xenobiticos formados durante el proceso. Los parmetros globales para el anlisis de la calidad del agua como, demanda qumica de oxigeno, carbn orgnico total, entre otros, no permiten identificar si el potencial toxicolgico es remediado despus de los tratamientos. El objetivo de este trabajo fue evaluar el desempeo de un reactor anaerobio horizontal de biomasa inmovilizada (RAHBI tratando un efluente real de blanqueamiento de celulosa Kraft, por medio de ensayos de toxicidad (Daphnia similis Ceriodaphnia silvestrii , mutagenicidad y citotoxicidad (Allium cepa L. . Los resultados mostraron alta sensibilidad de todos los organismos estudiados y buena capacidad del reactor anaerobio para remover compuestos que ejercen efectos txicos y mutagnicos. Los bioensayos estudiados representan una alternativa interesante para el anlisis de la calidad del agua y para la evaluacin del desempeo de tratamientos.

  4. Reproducibility of maximum aerobic power (VO2max) among soccer players using a modified heck protocol / Reprodutibilidade da potncia aerbia mxima (VO2max) em jogadores de futebol utilizando o protocolo de heck modificado

    Scientific Electronic Library Online (English)

    Paulo Roberto, Santos-Silva; Alfredo Jos, Fonseca; Anita Weigand de, Castro; Jlia Maria D' Andra, Greve; Arnaldo Jos, Hernandez.

    Full Text Available OBJETIVO: Determinar o grau de reprodutibilidade do consumo mximo de oxignio (VO2max) em jogadores de futebol utilizando o protocolo de Heck modificado. MTODOS: Foram avaliados por duas vezes, com intervalo de 15 dias entre os testes, 11 futebolistas masculinos. Todos eram de alto nvel, treinava [...] m em mdia 10 horas por semana subdivididos em treinamentos fsicos, tcnicos, tticos e jogos competitivos, totalizando cinco vezes por semana e na fase em que foram avaliados se encontravam em pleno perodo competitivo realizando um jogo por semana. Os futebolistas foram avaliados em esteira ergomtrica (1,2 km.h-1) a cada dois minutos e inclinao fixa durante o teste em 3%. O VO2max foi medido diretamente utilizando analisador metablico de anlise de gases expirados respirao-a-respirao. RESULTADOS: A velocidade mxima de corrida e o VO2max atingido nos dois testes foram respectivamente: (15,6 1,1 vs. 15,7 1,2 km.h-1; [p = 0,78]) e (54,5 3,9 vs. 55,2 4,4 ml.kg-1.min-1; [P = 0,88]). Houve correlao significante e alta do VO2max entre os dois testes aps 15 dias de intervalo [r = 0,97; P Abstract in english OBJECTIVE: To determine the degree of reproducibility of maximum oxygen consumption (VO2max) among soccer players, using a modified Heck protocol. METHODS: 2 evaluations with an interval of 15 days between them were performed on 11 male soccer players. All the players were at a high performance leve [...] l; they were training for an average of 10 hours per week, totaling 5 times a week. When they were evaluated, they were in the middle of the competitive season, playing 1 match per week. The soccer players were evaluated on an ergometric treadmill with velocity increments of 1.2 km.h-1 every 2 minutes and a fixed inclination of 3% during the test. VO2max was measured directly using a breath-by-breath metabolic gas analyzer. RESULTS: The maximum running speed and VO2max attained in the 2 tests were, respectively: (15.6 1.1 vs. 15.7 1.2 km.h-1; [P = .78]) and (54.5 3.9 vs. 55.2 4.4 ml.kg-1.min-1; [P = .88]). There was high and significant correlation of VO2max between the 2 tests with a 15-day interval between them [r = 0.97; P

  5. The VO-5 blower for coal industry and agriculture

    Energy Technology Data Exchange (ETDEWEB)

    Raskin, I.A.; Ivanov, S.K.; Karminskii, V.N.

    1984-01-01

    This article discusses design and performance testing of the VO-5 blower developed by the im. Vakhrushev electromechanical plant in Tomsk. The VO-5 is used at working places where explosion-proof housing is unnecessary. In comparison to the SVM-5M2 blower the VO-5 weighs 30% less and is 0.74% more efficient. The VO-5 with a rated power of 5.5 kW and capacity of 3.1 m/SUP/3/s produces a pressure of 125 daPa. The VO-5 weighs 125 kg, is 660 mm high and 595 mm wide. The designed mean-time-between-failures is 4,500 h (in comparison to 3,000 h of the SVM-5M2 blower), the actual mean-time-between-failures is more than 10,000 h. Noise level of the VO-5 is relatively low and does not exceed 85 dB. Aerodynamic characteristics of the VO-5 and the SVM-5M2 are given in a diagram.

  6. Reinvestigation of the synthesis of LiFeVO4

    International Nuclear Information System (INIS)

    Highlights: → We reinvestigated the synthesis of the LiFeVO4 compound. → We demonstrate that the recently reported LiFeVO4 phase is not a pure phase. → We proved by Rietveld refinement that LiFeVO4 is a mixture ofLiVO3 and Fe2O3. → We noticed some attempts to fraud (modification of the powder pattern) . - Abstract: The synthesis of LiFeVO4 composition has been performed in air starting from Li2CO3, Fe2O3, and V2O5 and using the standard solid-state reaction route reported by Refs. . Identical X-ray diffraction pattern has been obtained, however our careful analysis with MDI Jade 5.0 software does not agree with previously reported pure LiFeVO4 samples. The powder pattern has been perfectly indexed using the single crystal data of LiVO3 (C2/c, a = 10.16718 A, b = 8.415725 A, c = 5.884155 A and β = 110.489o) and α-Fe2O3 (R-3c, a = 5.035 A, c = 13.75 A).

  7. COMPARACIÓN DE UN REACTOR DE BIOMASA SUSPENDIDA Y UN REACTOR DE BIOMASA ADHERIDA PARA LA BIODEGRADACIÓN DE COMPUESTOS TÓXICOS PRESENTES EN AGUAS RESIDUALES DE REFINERÍAS DE PETRÓLEO

    Directory of Open Access Journals (Sweden)

    Lizet Marina NAVA URREGO

    2014-01-01

    Full Text Available Esta investigación comprende un estudio de tratamiento de aguas residuales de una refinería utilizando dos rectores biológicos discontinuos secuenciales (SBR, por sus siglas en inglés Sequencing Batch Reactor . El primero de ellos es un reactor de biomasa suspendida y el segundo es un reactor de biomasa adherida, en el cual se utilizaron soportes plásticos tipo Kaldnes K1. Debido a la diversidad y complejidad de las aguas residuales de refinerías, fue necesario aclimatar los microorganismos utilizando la estrategia de eficiencias fijas para garantizar una buena degradación de los compuestos difícilmente biodegradables o recalcitrantes. Los reactores operaron durante 45 días empleando ciclos de 24 h (llenado, tiempo de reacción, sedimentación, vaciado y tiempo muerto. La carga orgánica volumétrica aplicada a los reactores varió entre 0.44 - 0.54 kg DQO/m 3 d; las cargas orgánicas superficiales oscilaron entre 1.56 - 1.80 g DQO/m 2 d para el reactor de biomasa adherida. El desempeño de los reactores discontinuos secuenciales se evaluó mediante las eficiencias de remoción de DQO, COD y fenoles, obteniendo porcentajes de remoción de 75, 73 y 99 % en el reactor de biomasa suspendida, mientras que en el reactor de biomasa adherida se alcanzaron porcentajes de remoción de 77, 81 y 99 %, respectivamente. La concen - tración de sólidos suspendidos totales en el reactor de biomasa suspendida fue de aproximadamente 2200 mg SST/L mientras que en el reactor de biomasa adherida se registró entre 450 y 560 mg SST/L. La relación SSV/SST se mantuvo entre 0.8 y 1 en ambos reactores. La concentración de biomasa adherida a los soportes osciló entre 3.98 gST/m 2 y 5.45 gST/m 2 . En cada reactor se realizaron cuatro perfiles para evaluar la capacidad de los microorganismos para degradar el tipo sustrato al que fueron ex - puestos en un tiempo determinado. En ambos reactores, los perfiles de degradación 1 y 2 mostraron que la máxima remoción de DQO se presentó durante la primera hora de reacción, mientras que para los perfiles 3 y 4 la máxima remoción se alcanzó después de la segunda hora. En el caso de los fenoles, en todos los perfiles se obtuvo una remoción de más del 98 % durante la primera hora de reacción, indicando que en ambos reactores la biomasa fue capaz de degradar los compuestos tóxicos presentes en las aguas desflemadas sin importar el tipo de aglomeración microbiana utilizada

  8. Productividad y biomasa fitoperiftica en los Lagos Tarapoto y Yahuarcaca, Amazonas, Colombia Productividad y biomasa fitoperiftica en los lagos Yahuarcaca y Tarapoto (Amazonas - Colombia

    Directory of Open Access Journals (Sweden)

    Duque Escobar Santiago R.

    2000-06-01

    Full Text Available In the littoral zone, near of the matrix the macrophytes, main for Paspalum spp the lake Yahuarcaca and Tarapoto; the floodplain of the Amazon River-Colombia, through were designed system of artificial substratum, using slips and rods we quantify the productivity primary phytoperiphyton for clorophyl a, through method espectrophotometric and the biomass for ash free dry weight; in three periods hidrology low water, filling water and high water; for two, four and eigh day the colonization; four deep levels and radial position the substratum. The factors that has mayor effect over the primary productivity and the biomass phytoperiphytic are the hidrobiology periods, the colonization of the substratum and deep. The productivity and biomass from the lake is reationship with the mineralization of the water, with the tramsportation of nutrients of afluents, macrophytes, the flood forest, decomposition and the recirculation of nutrients in the water column.En la zona litorial, cerca de la matriz de macrfitas conformadas principalmente por Paspalum spp de los lagos Yahuarcaca y Tarapoto, del plano de inundacin del Ro Amazonas-Colombia, mediante el diseo de un sistema de substratos artificiales, utilizando lminas portaobjetos y tubos de vidrio, se cuantific la productividad primaria fitoperiftica por clorofila a, mediante el mtodo espectrofotomtrico y la biomasa por peso seco libre de cenizas (PSLC, en tres perodos hidrolgicos, aguas bajas, ascenso y altas o desborde; a los 2, 4 y 8 das de colonizacin; cuatro niveles de profundidad (cada 10 cm y diferente ubicacin radial de los substratos. Los factores que tienen mayor efecto sobre la productividad y biomasa fitoperiftica son los perodos hidrolgicos, los das de colonizacin de los substratos y la profundidad. La productividad y biomsa fitoperiftica de los lagos est relacionada con la mineralizacin de las aguas, el transporte de nutrientes de los afluentes, los macrfitos, el bosque inundable, la descomposicin de la materia orgnica y la recirculacin de nutrientes en la columna de agua.

  9. Anlisis de biomasa del vuelo de un rodal adulto de Pinus radiata Analysis of aboveground biomass in a mature stand of Pinus radiata

    OpenAIRE

    CLAUDIO MUOZ RIVEROS; JORGE CANCINO C; MIGUEL ESPINOSA B

    2005-01-01

    Se realiz un estudio de biomasa en rboles de Pinus radiata D. Don de 42 aos, obtenidos de un rodal ubicado entre las ciudades de Santa Juana y Nacimiento, VIII Regin, Chile. El rodal se diferenci en tres clases de copa: dominante, codominante e intermedio. En cada clase de copa se obtuvieron valores de biomasa para cada componente (madera, corteza, ramas, ramillas y acculas); la madera result ser el componente que ms aport a la biomasa total sobre el suelo (88,9%), seguido de la cort...

  10. Validade preditiva da medida e estimativas do VO2mx no desempenho de Mountain Bikers / Predictive validity of VO2mx measurement and estimates in Mountain Bikers' performance / Validez predictiva de la medida y estimativas del VO2mx en el desempeo de Mountain Bikers

    Scientific Electronic Library Online (English)

    Fernanda, Mainardi; Allan, Inoue; Fernando Augusto de Saboia, Pompeu; Tony Meireles, Santos.

    2015-02-01

    Full Text Available INTRODUO: considerando o racional para a utilizao das equaes preditivas na estimativa do VO2mx em atletas, nenhum estudo estabeleceu sua validade para o desempenho no mountain bike cross-country (XCO). OBJETIVO: comparar diferentes estratgias de determinao do VO2mx, de forma direta ou in [...] direta, para a predio do desempenho em uma prova real e outra simulada. MTODOS: 20 atletas de XCO do sexo masculino (31,6 6,8 anos; 68,1 6,5 kg; 175,5 5,7cm; 64,9 4,4 mL. kg-1.min-1), foram submetidos a trs sesses experimentais. A primeira visita consistiu na estratificao de risco, avaliao antropomtrica e teste progressivo mximo. Na segunda, foi realizada a prova simulada e, na terceira, foi realizada a competio de XCO. RESULTADOS: a correlao entre a prova simulada e as equaes preditivas do VO2mx de forma absoluta alcanaram relao quase perfeita (r ? 0,9). As correlaes entre a competio real e as estimativas de VO2mx relativizadas massa corporal alcanaram resultados classificados como muito altos (r = 0,7-0,89). As associaes entre a medida direta do VO2mx e a simulao apresentaram uma classificao baixa para valores relativos massa corporal (r = 0,10, IC95% -0,35 a 0,51). Para o desempenho real, a classificao foi moderada (r = 0,48, IC95% 0,009 a 0,78). CONCLUSO: o presente estudo foi o primeiro a demonstrar a validade preditiva das estimativas do VO2mx para o desempenho simulado e real de MTB. Em complemento, confirmou a baixa validade preditiva da medida direta do VO2mx para o mesmo propsito. Abstract in spanish INTRODUCCIN: considerando el racional para el uso de las ecuaciones predictivas en la estimativa del VO2mx en atletas de ciclismo, ningn estudio estableci su validez predictiva para el desempeo en el mountain bike cross-country (XCO). OBJETIVO: comparar diferentes estrategias de determinacin [...] del VO2mx, de forma directa o indirecta, para la prediccin del desempeo en una prueba real y otra simulada. MTODOS: veinte atletas de XCO del sexo masculino (31,6 6,8 aos; 68,1 6,5 kg; 175,5 5,7cm; 64,9 4,4 mL. kg-1.min-1), fueron sometidos a tres sesiones experimentales. La primera visita consisti en la estratificacin de riesgo, evaluacin antropomtrica y test progresivo mximo. En la segunda, fue realizada la prueba simulada y en la tercera fue realizada la competicin de XCO. RESULTADOS: la correlacin entre la prueba simulada y las ecuaciones predictivas del VO2mx de forma absoluta alcanzaron relacin casi perfecta (r ? 0,9). Las correlaciones entre la competicin real y las estimativas de VO2mx relativizada a la masa corporal alcanzaron resultados clasificados como muy grande (r = 0,7-0,89). Las asociaciones entre la medida directa del VO2mx y la simulacin presentaron clasificacin pequea para valores relativos a masa corporal (r = 0,10, IC95% -0,35 a 0,51). Para el desempeo real, la clasificacin fue moderada (r = 0,48, IC95% 0,009 a 0,78). CONCLUSIN: el presente estudio fue el primero en demostrar la validez predictiva de las estimativas del VO2mx para el desempeo simulado y real de MTB. En complemento, confirm la baja validez predictiva de la medida directa del VO2mx para el mismo propsito. Abstract in english INTRODUCTION: considering the rationale for the use of predictive equations to estimate VO2max in athletes, no study has established its validity for performance in mountain bike cross-country (XCO). OBJECTIVE: the aim was to compare different strategies for determining VO2max, directly or indirect [...] ly, for predicting performance in a simulated and in a real competition. METHODS: 20 XCO male athletes (31.6 6.8 anos; 68.1 6.5 kg; 175.5 5.7cm; VO2max 64.9 4.4 mL. kg-1.min-1), were submitted to three experimental sessions. In the first visit, there were risk stratification, anthropometric evaluation and maximum progressive test. In the second, a simulated race was performed and, in the third s

  11. The VO-Neural project: recent developments and some applications

    CERN Document Server

    Brescia, M; d'Angelo, G; D'Abrusco, R; Deniskina, N; Garofalo, M; Laurino, O; Longo, G; Nocella, A; Skordovski, B

    2008-01-01

    VO-Neural is the natural evolution of the Astroneural project which was started in 1994 with the aim to implement a suite of neural tools for data mining in astronomical massive data sets. At a difference with its ancestor, which was implemented under Matlab, VO-Neural is written in C++, object oriented, and it is specifically tailored to work in distributed computing architectures. We discuss the current status of implementation of VO-Neural, present an application to the classification of Active Galactic Nuclei, and outline the ongoing work to improve the functionalities of the package.

  12. Thermal properties of a novel compound PbVO3

    International Nuclear Information System (INIS)

    Effect of pressure on thermal properties of a multiferroic (MF) novel compound PbVO3 is studied using an atomistic approach. The temperature dependence of the specific heat (CP) (20K ? T ? 300 K) of PbVO3 has been studied and compared with the earlier experimental work. Also, this work reports, probably for the first time the relation of pressure to the Debye temperature (?D) along with other properties like bulk modulus (B), molecular force constant (f), Reststrahlen frequency (?0), thermal expansion (?) and Grneisen parameter of PbVO3 with the Modified Rigid Ion Model (MRIM).

  13. Fractal Nature of Metallic and Insulating Domain Configurations in a VO2 Thin Film Revealed by Kelvin Probe Force Microscopy

    OpenAIRE

    Sohn, Ahrum; Kanki, Teruo; Sakai, Kotaro; Tanaka, Hidekazu; Kim, Dong-Wook

    2015-01-01

    We investigated the surface work function (WS) and its spatial distribution for epitaxial VO2/TiO2 thin films using Kelvin probe force microscopy (KPFM). Nearly grain-boundary-free samples allowed observation of metallic and insulating domains with distinct WS values, throughout the metalinsulator transition. The metallic fraction, estimated from WS maps, describes the evolution of the resistance based on a two-dimensional percolation model. The KPFM measurements also revealed the fractal na...

  14. Room temperature magnetism in LaVO3/SrVO3 superlattices by geometrically confined doping

    OpenAIRE

    Luders, U.; Sheets, W. C; David, A.; Prellier, W.; Fresard, R.

    2009-01-01

    Based on the Hubbard model of strongly correlated systems, a reduction in the bandwidth of the electrons can yield a substantial change in the properties of the material. One method to modify the bandwidth is geometrically confined doping, i.e. the introduction of a (thin) dopant layer in a material. In this paper, the magnetic properties of LaVO$_3$/SrVO$_3$ superlattices, in which the geometrically confined doping is produced by a one monolayer thick SrVO$_3$ film, are presented. In contras...

  15. Disordered LiZnVO4 with a phenacite structure

    Directory of Open Access Journals (Sweden)

    Mohamed Azrour

    2010-05-01

    Full Text Available Single crystals of lithium zinc vanadate, LiZnVO4, were grown by the flux method. The structural type of this vanadate is characterized by a three-dimensional arrangement of tetrahedra sharing apices in an LiZnVO4 network. This arrangement contains three different tetrahedra, namely one [VO4] and two disordered mixed-site [Li/ZnO4] tetrahedra. The resulting lattice gives rise to hexagonal channels running along the [0001] direction. Both sites in the mixed-site [Li/ZnO4] tetrahedra are occupied by a statistical mixture of lithium and zinc with a 1:1 ratio. Therefore, LiZnVO4 appears to be the first vanadate known to crystallize with a disordered phenacite structure. Moreover, the resulting values of calculated bond valences (Li = 1.083, Zn = 2.062 and V = 5.185 tend to confirm the structural model.

  16. Audio CAPTCHA for SIP-Based VoIP

    Science.gov (United States)

    Soupionis, Yannis; Tountas, George; Gritzalis, Dimitris

    Voice over IP (VoIP) introduces new ways of communication, while utilizing existing data networks to provide inexpensive voice communications worldwide as a promising alternative to the traditional PSTN telephony. SPam over Internet Telephony (SPIT) is one potential source of future annoyance in VoIP. A common way to launch a SPIT attack is the use of an automated procedure (bot), which generates calls and produces audio advertisements. In this paper, our goal is to design appropriate CAPTCHA to fight such bots. We focus on and develop audio CAPTCHA, as the audio format is more suitable for VoIP environments and we implement it in a SIP-based VoIP environment. Furthermore, we suggest and evaluate the specific attributes that audio CAPTCHA should incorporate in order to be effective, and test it against an open source bot implementation.

  17. High pressure phase transitions in NdVO4

    Science.gov (United States)

    Panchal, V.; Errandonea, D.; Manjn, F. J.; Muoz, A.; Rodrguez-Hernndez, P.; Bettinelli, M.; Achary, S. N.; Tyagi, A. K.

    2015-06-01

    Raman-scattering measurements on NdVO4 suggest a pressure-induced zircon to monazite phase transition beyond 5.9 GPa. The monazite phase undergoes a second phase transition to a yet unknown phase at 18.1 GPa. Lattice-dynamics calculations well support the experimental findings and predict a possible orthorhombic structure for the post-monazite structure of NdVO4.

  18. A European Perspective of VoIP in Market Competition

    OpenAIRE

    FEIJÓO GONZÁLEZ Claudio; GOMEZ-BARROSO Jose-Luis; ROJO-ALONSO David

    2008-01-01

    The debate on the future of VoIP (Voice over Internet Protocol) is not new. For some time now this technological innovation has been considered one of main drivers for reshaping the telecommunications industry. Such is the case that even former Federal Communications Commission Chairman, Michael Powell, said at the Davos World Economic Forum (Switzerland, January 2004) that VoIP ¿is probably the most significant paradigm shift in the entire history of modern communications, since the inventio...

  19. The Astrophysical Virtual Observatory to EURO-VO Transition

    OpenAIRE

    PADOVANI, P

    2005-01-01

    The Astrophysical Virtual Observatory (AVO) initiative, jointly funded by the European Commission and six European organisations, had the task of creating the foundations of a regional scale infrastructure by conducting a research and demonstration programme on the VO scientific requirements and necessary technologies. The AVO project is now formally concluded. I highlight AVO's main achievements and then describe its successor, the EURO-VO project. With its three new interl...

  20. Update of the China-VO AstroCloud

    OpenAIRE

    Cui, Chenzhou; Yu, Ce; Xiao, Jian; He, Boliang; Li, Changhua; Fan, Dongwei; Wang, Chuanjun; Hong, Zhi; LI Shanshan; Mi, Linying; Wan, Wanghui; Cao, Zihuang; Wang, Jiawei; Yin, Shucheng; Fan, YuFeng

    2016-01-01

    As the cyber-infrastructure for Astronomical research from Chinese Virtual Observatory (China-VO) project, AstroCloud has been archived solid progresses during the last one year. Proposal management system and data access system are re-designed. Several new sub-systems are developed, including China-VO PaperData, AstroCloud Statics and Public channel. More data sets and application environments are integrated into the platform. LAMOST DR1, the largest astronomical spectrum archive was release...

  1. Two-dimensional VO2 photonic crystal selective emitter

    International Nuclear Information System (INIS)

    The design and simulation of a two-dimensional (2D) photonic crystal (PhC) selective emitter made of vanadium dioxide (VO2), a type metal oxide with a high temperature resistance, are reported. Spectral emission characteristics of the 2D VO2 PhCs were investigated using the finite difference time domain (FDTD) method. The PhC consists of a periodic array of cylindrical air microcavities. The influences of the geometric characteristic parameters are discussed. The influences of the radius and depth on the emission of the 2D VO2 PhC can be explained based on the coupled-mode theory. The emissivities at wavelengths below the cut-off wavelength were enhanced by increasing the depth. When the depth was much larger than the radius, the cut-off wavelength increased with the radius. The effect of the period on the emissivity at wavelengths less than the period was highly influenced by the diffraction modes. The designed 2D VO2 PhC emitter exhibited a selective emission that was well-matched with InGaAs cells. The spectral emissivities within the convertible wavelength range of the InGaAs cells reached 0.95, and the emissivities for non-convertible wavelengths were less than 0.3. - Highlights: • The lattice structure of metal phase VO2 does not change with temperature. • The influences of scales on the emission of a 2D VO2 PhC are discussed. • A 2D VO2 photonic crystal emitter matched well with InGaAs cell is designed. • The matched VO2 PhC emitter can highly improve the TPV system efficiency

  2. VoLTE performance in railway scenarios

    DEFF Research Database (Denmark)

    Sniady, Aleksander; Snderskov, Morten

    2015-01-01

    GSM-Railways (GSM-R) is the current standard for railway voice and data communication. GSM-R provides railway specific voice services, such as Railway Emergency Call (REC). GSM-R provides also the European Train Control System (ETCS), which offers in-cab signaling and Automatic Train Protection (ATP). Despite these features and services, GSM-R has various major shortcomings. Therefore, alternative technologies are considered to replace GSM-R and become the next generation railway mobile communication network. 3GPP Long Term Evolution (LTE) is a likely candidate for GSM-R replacement. LTE is more efficient, flexible and offers much higher capacity, which allows the railway network to provide new communication-based applications for railways. Most of the research on LTE in railways has been focused on data-based railway applications (ETCS signaling and other). Nevertheless, voice communication is still a crucial service for railways. Regardless of its advantages, LTE can only become a railway communication technology if it provides voice communication fulfilling railway requirements. This paper presents how Voice over LTE (VoLTE) can be used to build railway communication services. Examples of Railway Emergency Call and One-to-One Call are provided. Service performance, in terms of call setup times and voice transmission quality, is analyzed in simulation scenarios modelling two railway scenarios in Denmark.

  3. Audio Codecs in VoIPv6: A Performance Analysis

    Directory of Open Access Journals (Sweden)

    Monjur Ahmed

    2014-04-01

    Full Text Available Audio communications in IP based networks have been revolutionized by the introduction of VoIP applications. High cost-efficiency has made VoIP to be the communication means in todays world; and this trend is anticipated to be continued on an ongoing basis. The performance of VoIP significantly depends on the efficiency of the audio codecs used in any communication scenario which make the study on the performance issues of audio codecs in VoIP applications worth investigating. IPv6 is the new version of IP, which will gradually replace the current IPv4 as the transition from IPv4 to IPv6 is already in place. This demands the scrutiny of the audio codecs being used in IPv4 to be tested for their compatibility in IPv6 in terms of desired performance. This paper presents the study on the performance of selected audio codecs that are widely used in VoIPv4. G.711, G.729A and G.723.1 codecs were chosen for the study in VoIPv6 based scenarios presented in this paper. The selected audio codecs were applied in IPv6 based voice communication network scenarios to determine their performance efficiency by observing various QoS parameters. The study was done by means of simulation using OPNET.

  4. The preparation of a plasmonically resonant VO2 thermochromic pigment

    International Nuclear Information System (INIS)

    Vanadium dioxide (VO2) undergoes a reversible metal-insulator transition, normally at ∼68 0C. While the properties of continuous semi-transparent coatings of VO2 are well known, there is far less information available concerning the potential use of discrete VO2 nanoparticles as a thermochromic pigment in opaque coatings. Individual VO2 nanoparticles undergo a localized plasmon resonance with near-infrared light at about 1100 nm and this resonance can be switched on and off by simply varying the temperature of the system. Therefore, incorporation of VO2 nanoparticles into a coating system imbues the coating with the ability to self-adaptively modulate its own absorptive efficiency in the near-infrared. Here we examine the magnitude and control of this phenomenon. Prototype coatings are described, made using VO2 powder produced by an improved process. The materials are characterized using calorimetry, x-ray diffraction, high-resolution scanning electron microscopy, transmission electron microscopy, and by measurement of optical properties.

  5. Conductividad trmica del suelo, materia orgnica, actividad y biomasa microbianas en sistemas de cultivo de maracuy en toro, valle del cauca

    OpenAIRE

    Rojas, Adriana; Zu?n?iga, Orlando; Snchez de Prager, Marina; Prez, Jess; Gasc, Jos Mara

    2007-01-01

    El estudio evalu la relacin entre la conductividad trmica del suelo (λ), la materia orgnica, la actividad y la biomasa microbianas. En tres sistemas de cultivo de maracuy (agroecolgico, transicin y convencional) en el municipio de Toro (Valle del Cauca), en nueve puntos por manejo se tomaron muestras al azar a dos profundidades (0-15 y 15-30 cm) y se midieron propiedades biolgicas: (actividad microbiana (C-CO2); biomasa microbiana (C microbiano) –fumigacin, extraccin– y propied...

  6. Actividad y biomasa microbianas como indicadores de materia orgnica en sistemas de cultivo de maracuy (passiflora edulis) en toro, valle del cauca, colombia

    OpenAIRE

    Snchez de Prager, Marina; Rojas, Adriana; Prez, Jess; Zu?n?iga, Orlando; Gasc, Jos Mara

    2007-01-01

    El estudio evalu la relacin entre materia orgnica del suelo, actividad y biomasa microbianas. Se usaron tres sistemas de cultivo de maracuy (agroecolgico, transicin y convencional) en el municipio de Toro (Valle del Cauca). En muestras tomadas al azar en dos profundidades (0-15 y 1530 cm). En nueve puntos por sistema de manejo se midieron propiedades biolgicas [actividad microbiana (C-CO2); biomasa microbiana (Cmicro) -fumigacin, extraccin- y propiedades fsicas y qumicas (materia o...

  7. Conversin de biomasa recalcitrante originada en la produccin de etanol a partir de la planta de banano y su fruto en combustibles mediante procesos de pirolisis

    OpenAIRE

    Giraldo Rivera, Oscar Daro

    2012-01-01

    Se estudi la pirlisis de la biomasa recalcitrante (residuos slidos de la planta de banano y su fruto obtenidos del proceso de extraccin del etanol) en un reactor de cada libre a escala de laboratorio. El sistema de experimentacin, diseado especficamente para este estudio, permite caracterizar la pirlisis de la biomasa en un rgimen que se encuentra entre la pirlisis rpida y la lenta dada la alta velocidad de calentamiento y el corto tiempo de residencia de la partcula, pero a su v...

  8. Distribucin de biomasa de Barleria lupulina Lindl. en respuesta a tres regmenes de riego Biomass distribution of Barleria lupulina Lindl. in response to three watering regimes

    OpenAIRE

    V Paz; Vera, A.; Pez, A.

    2003-01-01

    Barleria lupulina es un planta con propiedades medicinales potenciales, cuya acumulacin de fitomasa, a nivel de sus rganos, ha sido poco investigada. Se determin la distribucin de biomasa de B. lupulina Lindl. en respuesta a tres regmenes de riego. Se disearon, por triplicado, tres tratamientos de riego: cada 2 (RI), 5 (RII) y 15 (RIII) das. Se realizaron mediciones del contenido relativo de agua (CRA), el potencial hdrico, y determinaciones de rea foliar y biomasa seca a los seis me...

  9. The Euro-VO Registry, Re-engineering the Back-end

    Science.gov (United States)

    Arviset, C.; Perdikeas, M.; Osuna, P.; Gonzalez, J.

    2015-09-01

    The Euro-VO Registry, located, developed and operated at ESAC, is one of the full searchable registries available worldwide, gathering information about all VO-compliant resources. The Euro-VO Registry serves as a registration point for European - and other countries- VO actors and data centres wishing to publish VO services. It harvests other registries to ensure its completeness so VO applications developers and VO users can use it to discover all VO resources, from Europe and from all other VO projects. The Euro-VO Registry provides as well a harvesting interface to other registries in the world to make sure the European VO services are also included in all other worldwide full registries. In particular, the new Euro-VO registry will be supporting the new RegTAP search interface for the relational registry allowing arbitrary ADQL queries against its contents over a compliant TAP service. The recently obsolete (for future developments) SOAP-based legacy search interface will also be supported for backwards compatibility purposes. Furthermore, in the context of the IVOA, some quality control and curation procedures for the registry resources are being defined. The Euro-VO Registry implements these procedures to ensure the high quality of the VO resources it references. This paper gives an overview of the recent development of the new Euro-VO Registry, together with its new curation facilities, both of which are being performed under a contract awarded to Neuropublic, under ESA special initiative to Greece.

  10. Control de una planta prototipo de gasificacin de biomasa mediante redes neuronales

    Scientific Electronic Library Online (English)

    Carlos A., Forero Nez; Jos U., Castellanos Contreras; Fabio E., Sierra Vargas.

    Full Text Available Los sistemas de gasificacin de Biomasa son una alternativa para emplear residuos agroindustriales y generar un combustible gaseoso; sin embargo, estos procesos no lineales se ven afectados por las caractersticas tpicas del material y por la variacin en las temperaturas al interior del equipo, po [...] r lo tanto se requieren sistemas de control para alcanzar estados estables en el tiempo. Este trabajo analiza el desempeo de un control mediante redes neuronales aplicado a un gasificador de lecho fijo corriente descendente cuando se emplean cascaras de coco o cuesco de palma. Los resultados indican que el uso del sistema de control en el equipo, alimentado con cascaras de coco, permite aumentar las temperaturas en el reactor de 600C a 800C en la zona de inyeccin, superando as el problema derivado de la baja transferencia de energa por conduccin a travs del sistema. Cuando se emplea el control en la gasificacin de cuesco, la temperatura promedio se mantuvo constante en 790C, el CO presente en el gas estuvo alrededor de 10% mientras que el CO2 disminuy a 4%. La aplicacin de un sistema de control mediante redes neuronales es una gran alternativa puesto que se puede entrenar para cada tipo de biomasa mejorando la estabilidad del sistema y produciendo un gas de sntesis con menor contenido de CO2. Esto para un pas con gran diversidad de recursos agroindustriales abre la posibilidad de usar estos subproductos en la generacin de energa a partir de fuentes renovables. Abstract in english The gasification power systems are a remarkable alternative because they can use agro-industrial wastes to produce clean syngas; although, the differences between the biomass properties and the inner temperatures throughout the equipment make compulsory the use of control systems to achieve stable s [...] tates. This work aims to analyze the effect of applying a Neural Network Control System on a Downdraft fixed bed gasifier fed with Coconut shells and Oil Palm shells. Results show that the use of the control system on the equipment fed with coconut shells increased the maximum temperature at the air injection zone from 600C to 800C, which overcomes the problems found by the low thermal conductivity of the coconut shells. With the control system and the equipment fed with oil palm shells, the maximum temperature was 790C; the CO in the syngas was stable at 10%, whereas the CO2 decreased to 4%. The Neural Network control system is useful because this can be trained for each biomass, resulting on stable temperatures and low CO2 syngas. This improves the chances of producing energy from renewable resources in a country with a lot of agro-industrial byproducts like Colombia.

  11. Relacin entre la biomasa y algunas caractersticas morfolgicas de las bromelias fitotelmatas de un bosque alto andino colombiano

    OpenAIRE

    Isaza, Carolina; Betancur, Julio

    2012-01-01

    Se evaluaron algunas caractersticas morfolgicas para seis especies de bromelias fitotelmata (Guzmania gloriosa, Racinaea tetrantha, Tillandsia biflora, T. complanata, T. fendleri y T. turneri) con el fin de establecer cuales caractersticas podran utilizarse como estimadores indirectos de la biomasa total de la planta. El estudio se realiz en un bosque alto andino de la Sabana de Bogot, Colombia, ubicado a 2900 m de altitud. Para cada especie se recolectaron entre 32 y 64 individuos en d...

  12. Desempeo productivo de pollos de engorde suplementados con biomasa de saccharomyces cerevisiae derivada de la fermentacin de residuos de banano

    OpenAIRE

    Medina, N. M.; C.A. Gonzlez; Daza, S. L.; Restrepo, O.; Barahona Rosales, R.

    2014-01-01

    El objetivo de esta investigacin fue evaluar el efecto de la inclusin de diferentes niveles de biomasa de levaduras producidas al fermentar hidrolizados de residuos de la industria bananera sobre los parmetros zootcnicos de pollos de engorde, evaluando adems el impacto econmico de su uso en las dietas. El estudio se realiz en el Centro Agrario San Pablo de la Universidad Nacional Sede Medelln. Se utilizaron 210 pollos de engorde de un da de edad, distribuidos completamente al azar en...

  13. Estimacin de biomasa en herbceas a partir de datos hiperespectrales, regresin PLS y la transformacin continuum removal

    OpenAIRE

    M. Marabel-Garca; F. lvarez-Taboada

    2014-01-01

    El objetivo del estudio fue comparar los resultados de dos mtodos para la estimacin de la biomasa areaa partir de datos de espectroradiometra de campo: (i) regresin por mnimos cuadrados parciales (Partial Least SquaresRegression, PLSR) y (ii) regresin lineal utilizando los ndices Profundidad del Mnimo (Maximum Band Depth, MBD)y rea Sobre el Mnimo (Area Over the Minimum, AOM) como descriptores. En ambos casos se llev a cabo una previatransformacin de los espectros mediante Con...

  14. Efecto de lixiviados del raquis de pltano sobre la actividad y biomasa microbiana en floracin y cosecha del tomate

    OpenAIRE

    Muoz V. Rosa Elvira; Madrin Molina R.

    2006-01-01

    Se utilizaron cinco tratamientos: el testigo (T0) y cuatro concentraciones de lixiviados (T1= 100%, T2= 75%, T3= 50% y T4= 25%) aplicados 15, 30 y 60 das despus del trasplante. La actividad microbiana se determin con la metodologa del CAB y la biomasa microbiana con el mtodo de fumigacin-extraccin. En la actividad microbiana se encontraron diferencias significativas entre los tratamientos, presentando la aplicacin del lixiviado a la menor concentracin (25%) la mayor actividad (56.76 ...

  15. PRODUCCIN DE PROTENA Y BIOMASA PROBITICA DE Lactobacillus casei LIOFILIZADAS A PARTIR DE SUERO DE LECHE DE CABRA

    OpenAIRE

    E. J. Aguirre-Ezkauriatza; A. Ramrez-Medrano; J. M. Aguilar-Yez; M. M. lvarez

    2009-01-01

    En este trabajo se documenta la factibilidad tcnica de obtencin de dos productos de valor agregado a partir de suero de leche de cabra: (a) protena liofilizada y (b) biomasa probitica liofilizada de Lactobacillus casei. Se presentan resultados de experimentos de ultrafiltracin de suero de leche de cabra (SLC), del cual se retiene protena con una alta relacin protena/lactosa. En su forma liofilizada, esta protena present caractersticas de solubilidad superiores a productos comercial...

  16. Crecimiento, Abundancia Y Biomasa De Poecilia reticulata En El Lago Urbano Del Parque Tezozomoc De La Ciudad De Mxico

    Directory of Open Access Journals (Sweden)

    G. Elas-Fernndez

    2006-01-01

    Full Text Available Los lagos urbanos tienen importancia esttica, recreativa, cultural y biolgica por albergar organismos generalmente alctonos, como aves, reptiles, insectos y peces, en particular poecilidos, los cuales son muy tolerantes y se reproducen con facilidad. Por lo anterior, el objetivo de este trabajo fue: determinar la variacin en la abundancia y biomasa de Poecilia reticulata en el lago del parque Tezozomoc, as como obtener la ecuacin de crecimiento. Se realizaron muestreos mensuales de julio del ao 2000 a junio del 2001. Se establecieron tres estaciones donde se registraron las siguientes variables fsicas y qumicas; transparencia, alcalinidad, dureza, pH, conductividad, temperatura y turbiedad por mtodos convencionales. Los peces se capturaron con una red de cuchara de marco rectangular de 100 x 50 cm (rea barrida de 0.5 m2, con luz de malla de 0.5 cm. Los organismos se fijaron con formalina al 10 %. Se registraron las siguientes variables morfomtricas de los organismos; peso (gr y longitud patrn (mm. Se calcul la abundancia y biomasa, as como la ecuacin de crecimiento de acuerdo al modelo de Von Bertalanffy. Se encontr que el agua del sistema es templada, turbia, alcalina, dura y somera. La mayor abundancia (6,148 organismos y biomasa (677.28 g se present en la estacin I, caracterizada por la mayor presencia de visitantes al lago que arroja desperdicios alimenticios al sistema. Los meses con mayor abundancia fueron julio (1,483 org y agosto (1,252 org y los de mayor biomasa agosto (145.12 gr y marzo (138.63 gr. La longitud mxima obtenida de 61.55 mm y la tasa de crecimiento de 0.2987 son valores similares a los obtenidos en sistemas naturales.

  17. Consideraciones sobre la produccin de etanol a partir de la biomasa lignocelulsica

    Directory of Open Access Journals (Sweden)

    Jos C. Villar

    2008-01-01

    Full Text Available En los ltimos aos, como consecuencia del aumento de los precios del petrleo y las exigencias ecolgicas, ha crecido el inters por la produccin de bioetanol como combustible de vehculos automotores. En Brasil y EEUU, los principales productores, se estima una produccin por cada pas en el 2006 de alrededor de los 19 mil millones de litros. Brasil planea aumentar la produccin hasta 26.5 mil millones en el 2016 mientras que para esa misma fecha EEUU pretende alcanzar los 45,4 mil millones de litros. Las materias primas ms empleadas son maz y caa de azcar. Sera de inters incluir entre stas a la biomasa lignocelulsica que se obtiene como subproductos agrcolas y forestales (pajas de cereales, bagazo, aserrn y virutas de madera que no son aptos para el consumo humano y por su composicin qumica son susceptibles de ser sacarificados por hidrlisis qumica o enzimtica. Se analizan crticamente las posibles vas para desarrollar la produccin de alcohol a partir de estos materiales, en especial la va qumica, cuya perspectiva de xito se encuentra estrechamente vinculada al desarrollo de reactores continuos. De esta manera, se pueden intensificar las condiciones de reaccin que permitan incrementar la productividad del proceso, mediante la obtencin de los mximos rendimientos de azcares con el empleo de los menores volmenes del equipamiento, sin descuidar la disminucin de la concentracin de sustancias inhibidoras de la fermentacin en el sistema.

  18. Estimacin de Iluminacin en un Fotobiorreactor Productor de Biomasa a Partir de Microalgas

    Directory of Open Access Journals (Sweden)

    Carlos Francisco Gonzlez Hernndez

    2014-01-01

    Full Text Available En el presente trabajo se realiz el anlisis de iluminacin artificial para un fotobiorreactor productor de biomasa a partir de microalgas, el cual fue diseado previamente con fines en aplicacin para la produccin de biocombustibles. En el anlisis, se utiliz como herramienta la tcnica de contornos o tambin conocida como mtodo de superficie de respuesta, para lo cual se establecieron 132 puntos de intensidad luminosa distribuidos de forma simtrica a diferentes alturas del contenedor. Se realizaron dos bioensayos uno con la iluminacin en la parte inferior del recipiente usando Diodos Emisores de Luz (LEDs, por sus siglas en ingls y el otro adicionando 3 lmparas fluorescentes ms, situadas perifricamente a la mitad de la altura total del fotobiorreactor. Los resultados de las mediciones muestran una mejora en el sistema de iluminac in que favorece la reproduccin continua de las microalgas, cuando se utiliz la combinacin de luz emitida por LEDs y por lmparas fluorescentes. Esta combinacin de sistemas de iluminacin gener las condiciones para poder realizar las funciones metablicas de las microalgas, quienes necesitan en promedio 2500 lx de forma homognea.

  19. Recuperacin de la biomasa mediante la sucesin secundaria, Cordillera Central de los Andes, Colombia

    Directory of Open Access Journals (Sweden)

    Jorge Ignacio del Valle

    2011-09-01

    Full Text Available En bosques secundarios premontanos tropicales es escasa la informacin sobre el tiempo requerido para recuperar la biomasa area y subterrnea de los primarios. Por lo tanto, establecimos 33 parcelas de 0.1ha entre 550 y 1 700m en bosques secundarios que cubran estadios serales de 3 a 36 aos y estimamos la biomasa de las plantas y de las races gruesas con ecuaciones locales. As como la biomasa de las pasturas y barbechos por cosecha de 54 y 18 parcelas, respectivamente. Tambin se calcul la edad de las parcelas con informantes locales, sensores remotos, C14 y anillos de crecimiento. En cada parcela medimos la biomasa area viva por hectrea (Bav y la de las races gruesas por hectrea (Brg. Modelamos la Bav y Brg en funcin de la edad mediante la ecuacin de von Bertalanfy con asntotas de 247t/ha (Bav y 66t/ha (Brg resultantes de la medicin de 33 parcelas de 0.1ha en los bosques primarios. Con la razn Brg/Bav=f(t estimamos 87 aos para que los bosques secundarios recuperen la Bav existente en los primarios y 217 aos para recuperar la Brg. La tasa mxima de crecimiento instantneo de la Bav fue 6.95t/ha/ao a los 10 aos y la tasa media mxima de crecimiento 6.26t/ha/ao a los 17 aos. La media ponderada de la tasa de crecimiento absoluto de la Bav alcanz 4.57t/ha/ao y la relativa 10% anual. La razn Brg/Bav inicialmente aumenta muy aceleradamente hasta 4-5 aos (25%, luego disminuye hasta 25 aos (18% para luego incrementar hasta 26.7Biomass recovery through secondary succession in the Cordillera Central de los Andes, Colombia. Estimations on biomass recovery rates by secondary tropical forests are needed to understand the complex tropical succession, and their importance on CO2 capture, to offset the warming of the planet. We conducted the study in the Porce River Canyon between 550 and 1 700m.a.s.l. covering tropical and premontane moist belts. We established 33 temporary plots of 50mx20m in secondary forests, including fallows to succesional forests, and ranging between 3 and 36 years old; we measured the diameter at breast height (D of all woody plants with D?5cm. In each one of these plots we established five 10mx10m subplots, in which we measured the diameter betweem 1cm?D<5cm of all woody plants. We estimated the biomass of pastures by harvesting 54 plots of 2mx2m, and of shrubs in the fallows by harvesting the biomass in 18 plots of 5mx2m. We modeled Bav (above ground live biomass of woody plants and Brg (coarse root biomass as a function of succesional age (t with the growth model of von Bertalanffy, using 247t/ha and 66t/ha as asymptote, respectively. Besides, we modeled the ratios brg/bav=f(D and Brg/Bav=f(t. The model estimated that 87 years are required to recover the existing Bav of primary forests through secondary succession, and 217 years for the Brg of the primary forest. The maximum instantaneous growth rate of the Bav was 6.95 t/ha/yr at age 10. The maximum average growth rate of the Bav was 6.26 t/ha/yr at age 17. The weighted average of the absolute growth rate of the Bav reached 4.57t/ha/yr and the relative growth rate 10% annually. The ratio brg/bav decreases with increasing D. The ratio Brg/Bav initially increases very rapidly until age 5 (25%, then decreases to reach 25 years (18% and increases afterwards until the ratio reaches the asymptote (26.7%. Rev. Biol. Trop. 59 (3:1337-1358. Epub 2011 September 01.

  20. Spectroscopic Analysis in the Virtual Observatory Environment with SPLAT-VO

    CERN Document Server

    Skoda, Petr; Neves, Margarida Castro; Andresic, David; Jenness, Tim

    2014-01-01

    SPLAT-VO is a powerful graphical tool for displaying, comparing, modifying and analyzing astronomical spectra, as well as searching and retrieving spectra from services around the world using Virtual Observatory (VO) protocols and services. The development of SPLAT-VO started in 1999, as part of the Starlink StarJava initiative, sometime before that of the VO, so initial support for the VO was necessarily added once VO standards and services became available. Further developments were supported by the Joint Astronomy Centre, Hawaii until 2009. Since end of 2011 development of SPLAT-VO has been continued by the German Astrophysical Virtual Observatory, and the Astronomical Institute of the Academy of Sciences of the Czech Republic. From this time several new features have been added, including support for the latest VO protocols, along with new visualization and spectra storing capabilities. This paper presents the history of SPLAT-VO, it's capabilities, recent additions and future plans, as well as a discussi...

  1. Template-Engaged In Situ Synthesis of Carbon-Doped Monoclinic Mesoporous BiVO4: Photocatalytic Treatment of Rhodamine B

    Science.gov (United States)

    Yao, Mingming; Gan, Lihua; Liu, Mingxian; Tripathi, Pranav K.; Liu, Yafei; Hu, Zhonghua

    2015-06-01

    In this paper, carbon-doped monoclinic scheelite mesoporous bismuth vanadate was synthesized through template-engaged in situ method. The bismuth nitrate pentahydrate and ammonia metavanadate were used as bismuth and vanadium precursors, respectively, glucose as carbon source, and mesoporous SiO2 aerogel as a hard template. Carbon-doped monoclinic mesoporous BiVO4 were obtained by heat treatment of BiVO4/glucose/template to carbonize glucose and form monoclinic crystal, followed by etching with NaOH solution to remove the SiO2 template. The samples were characterized by x-ray diffraction, N2 adsorption and desorption, UV-visible spectroscopy, Energy dispersive spectrometry, Raman spectroscopy, and Transmission electron microscopy. It was found that the sample with a carbon content of 0.5 wt.% possesses a specific surface area of 10.2 m2/g and has mesoporous structure with the most probable pore size of 13.9 nm. The band gap of carbon-doped monoclinic mesoporous BiVO4 was estimated to be 2.33 eV, indicating the superior photocatalytic activity under visible light. The photocatalytic efficiency of carbon-doped monoclinic mesoporous BiVO4 for the degradation of Rhodamine B under visible light (? > 400 nm) in 120 min reaches 98.7%, Besides, the carbon-doped monoclinic mesoporous BiVO4 photocatalyst still showed high stability: 85% for Rhodamine B degradation after ten recycles.

  2. Electronic structure and insulating gap in epitaxial VO2 polymorphs

    Directory of Open Access Journals (Sweden)

    Shinbuhm Lee

    2015-12-01

    Full Text Available Determining the origin of the insulating gap in the monoclinic V O2(M1 is a long-standing issue. The difficulty of this study arises from the simultaneous occurrence of structural and electronic transitions upon thermal cycling. Here, we compare the electronic structure of the M1 phase with that of single crystalline insulating V O2(A and V O2(B thin films to better understand the insulating phase of VO2. As these A and B phases do not undergo a structural transition upon thermal cycling, we comparatively study the origin of the gap opening in the insulating VO2 phases. By x-ray absorption and optical spectroscopy, we find that the shift of unoccupied t2g orbitals away from the Fermi level is a common feature, which plays an important role for the insulating behavior in VO2 polymorphs. The distinct splitting of the half-filled t2g orbital is observed only in the M1 phase, widening the bandgap up to ?0.6 eV. Our approach of comparing all three insulating VO2 phases provides insight into a better understanding of the electronic structure and the origin of the insulating gap in VO2.

  3. Structural characterization of PrVO3 epitaxial thin films

    CERN Document Server

    Copie, O; Boullay, P; Morales, M; Pautrat, A; David, A; Mercey, B; Pravarthana, D; Infante, I C; Janolin, P -E; Prellier, W

    2014-01-01

    Rare earth perovskite oxides constitute a wide family of materials presenting functional proper- ties strongly coupled to their crystalline structure. Here, we report on the experimental results on epitaxial PrVO3 deposited on SrTiO3 single crystal substrates by pulsed laser deposition. By com- bining advanced structural characterization tools, we have observed that the PVO unrelaxed film structure grown on STO, is characterized by two kinds of oriented domains whose epitaxial relations are: (i) PrVO3[110]o//SrTiO3[001]c and PrVO3[001]o//SrTiO3[100]c, (ii) PrVO3[110]o//SrTiO3[001]c and PrVO3[001]o//SrTiO3[010]c. We have also measured reciprocal space maps. From these results, we have determined that the PVO film epitaxy on STO imposes a lowering of the PVO structure symmetry from orthorhombic (Pbnm) to monoclinic (P21/m). We show, the nominal strain induced by the substrate being constant, that the obtained film structure depends on both growth oxygen and temperature. Thus, by finely controlling the depositio...

  4. Thermochromic characteristics of Ti-doped VO2 thin film

    Science.gov (United States)

    Lee, Hwasoo; Ko, Kyung Hyun; Choi, Jun Oh

    2014-03-01

    Utilizing metal-to-insulator transition (MIT) properties of V-oxide film, stable VO2 phase is necessary. In sputtering deposition of VO2, simple target preparation and high deposition rate are recommendable. For this, VO2 film was deposited on quartz substrate by RF magnetron sputter system under low working pressure using V2O5 target. Due to the lower sputtering yield of oxygen compared to vanadium, oxygen ion contents is usually deficient from that of target. So, the reduction of V ions was a result of charge compensation with the oxygen ions. Under lower working pressure, deposition rate become higher so that this deficiency is getting larger to cause further reduction to destabilize VO2. Preventing this, titanium oxide co-deposition was suggested to enrich oxygen source. When TiO2 was used, Ti ion has stable +4 charge state so that extra oxygen sputtered prevents V ion reduction below +4 state. But, in case of TiO, Ti ions were oxidized from +2 to +3 and +4 state and V ions with less oxidation potential should be reduced to +3 or so. Pure VO2 film had MIT at 66C and large resistivity ratio of 4 orders of magnitude from 30C to 90C. Under low working pressure, (V2O5 + TiO2) system yield fairly good films, while films with poor or absence of MIT were produced with TiO case.

  5. Thermochromic VO2 on Zinnwaldite Mica by pulsed laser deposition

    International Nuclear Information System (INIS)

    Highlights: • Vanadium dioxide was successfully synthesized by pulsed laser deposition method on mica. • The morphology evolution within the samples is characterized by a change from isolated and less-percolating (0 1 1) VO2 crystallites to a percolating granular configuration. • Without any post annealing, the films exhibit a textured nature with a VO2 (0 1 1) preferred crystallographic orientation and an elevated thermal variation of the electric resistance ratio RS/RM through the SMT at T ≈ 68 °C of the order of 104 and a narrow ∼7 °C hysteresis. - Abstract: VO2 thin films have been deposited by pulsed laser deposition on Zinnwaldite Mica substrates. The crystal structure, chemical composition, morphology were determined and the semiconductor/metal transition (SMT) properties of the deposited films were investigated. Without any post annealing, the films exhibit a textured nature with a VO2 (0 1 1) preferred crystallographic orientation and an elevated thermal variation of the electric resistance ratio RS/RM through the SMT at T ≈ 68 °C of the order of 104 and a narrow ∼7 °C hysteresis. In addition, the growth of the VO2 crystallites seem to be governed likely by a Volmer-Weber or Stranski-Krastanov mechanisms and certainly not a Frank-van Der Merwe process

  6. Electronic structure and insulating gap in epitaxial VO2 polymorphs

    Science.gov (United States)

    Lee, Shinbuhm; Meyer, Tricia L.; Sohn, Changhee; Lee, Donghwa; Nichols, John; Lee, Dongkyu; Seo, Sung S. Ambrose; Freeland, John W.; Noh, Tae Won; Lee, Ho Nyung

    2015-12-01

    Determining the origin of the insulating gap in the monoclinic V O2(M1) is a long-standing issue. The difficulty of this study arises from the simultaneous occurrence of structural and electronic transitions upon thermal cycling. Here, we compare the electronic structure of the M1 phase with that of single crystalline insulating V O2(A) and V O2(B) thin films to better understand the insulating phase of VO2. As these A and B phases do not undergo a structural transition upon thermal cycling, we comparatively study the origin of the gap opening in the insulating VO2 phases. By x-ray absorption and optical spectroscopy, we find that the shift of unoccupied t2g orbitals away from the Fermi level is a common feature, which plays an important role for the insulating behavior in VO2 polymorphs. The distinct splitting of the half-filled t2g orbital is observed only in the M1 phase, widening the bandgap up to 0.6 eV. Our approach of comparing all three insulating VO2 phases provides insight into a better understanding of the electronic structure and the origin of the insulating gap in VO2.

  7. Room-temperature magnetism in LaVO3/SrVO3 superlattices by geometrically confined doping

    Science.gov (United States)

    Lders, U.; Sheets, W. C.; David, A.; Prellier, W.; Frsard, R.

    2009-12-01

    Based on the Hubbard model of strongly correlated systems, a reduction in the bandwidth of the electrons can yield a substantial change in the properties of the material. One method to modify the bandwidth is geometrically confined doping, i.e., the introduction of a (thin) dopant layer in a material. In this Rapid Communication, the magnetic properties of LaVO3/SrVO3 superlattices, in which the geometrically confined doping is produced by a one monolayer thick SrVO3 film, are presented. In contrast to the solid solution La1-xSrxVO3 , such superlattices have a finite magnetization up to room temperature. Furthermore, the total magnetization of the superlattice depends on the thickness of the LaVO3 layer, indicating an indirect coupling of the magnetization that emerges at adjacent dopant layers. Our results show that geometrically confined doping, like it can be achieved in superlattices, reveals a way to induce otherwise inaccessible phases possibly even with a large temperature scale.

  8. Correlao entre as medidas direta e indireta do VO2max em atletas de futsal / Correlation between direct and indirect VO2max measurements in indoor soccer players / Correlacin entre las medidas directa e indirecta del VO2max en atletas de futsal

    Scientific Electronic Library Online (English)

    Anna Myrna Jaguaribe de, Lima; Daniele Vanusca Gomes, Silva; Alexandre Oscar Soares de, Souza.

    2005-06-01

    Full Text Available A importncia das qualidades morfofuncionais na melhora do rendimento nos esportes aumentou o interesse no aprimoramento dos nveis de aptido fsica dos atletas. No entanto, h poucos estudos sobre as variveis fisiolgicas do futsal disponveis na literatura cientfica mundial. Dessa forma, o obje [...] tivo deste estudo foi verificar a existncia de correlao entre os testes de medida direta e indireta do VO2max, em jogadores de futsal. Foram analisados 13 jogadores de futsal, com idade de 18,6 1,9 anos, altura igual a 177,1 3,5cm, peso de 68,5 9,5kg, ndice de massa corporal (IMC) de 21,7 2,3kg/m. Para medida direta do VO2max foi utilizado o sistema ergoespiromtrico computadorizado (VO-2000, Aerosport, Medgraphics, St. Paul, Minnesota) e para mensurao indireta do VO2max foi realizado o teste de campo de 3.200m. A anlise estatstica foi elaborada atravs do teste t de Student para amostras pareadas e pelo coeficiente de correlao de Pearson. Os valores de VO2max obtidos no teste de medida direta no apresentaram diferenas significativas em relao medida indireta (62,8 10,1 vs. 58,5 8,5ml/kg/min, respectivamente). Quando correlacionados os valores de VO2max obtidos em ambos os testes, observou-se forte correlao (r = 0,72). Em concluso, os testes de medida indireta apresentam boa aceitao para os atletas de futsal, tendo em vista a alta correlao com os testes de medida direta, o baixo custo de sua aplicao e o fornecimento de informaes importantes que podem auxiliar na prescrio e no acompanhamento do treinamento. Abstract in spanish La importncia de las cualidades morfo-funcionales en la mejora del rendimiento en los deportes aument el interes en el acondicionamiento de los niveles de aptitud fsica de los atletas. En tanto, hay pocos estudios sobre las variables fisiolgicas del futsal disponibles en la literatura mundial. D [...] e esta forma, el objetivo del estudio fu verificar la existencia de la correlacin entre los tests de medida directa e indirecta del VO2max, en jugadores de futsal. Fueron analizados 13 jugadores de futsal, con edades de entre 18,6 1,9 aos, altura igual a 177,1 3,5 cm, peso de 68,5 9,5 kg, ndice de masa corporal (IMC) de 21,7 2,3 kg/m. Para la medida directa del VO2max fu utilizado el sistema ergoespiromtrico computadorizado (VO-2000, Aerosport, Medgraphics, St. Paul, Minnesota) para mensura indirecta del VO2max fu realizado el test de campo de 3200m. El anlisis estatstico fu elaborado a travs del test t-Student para las muestras pareadas y por el coeficiente de correlacin de Pearson. Los valores de VO2max obtenidos en el test de medida directa no presentaron diferencias significativas en relacin a la medida indirecta (62,8 10,1 vs. 58,5 8,5 ml/kg/min, respectivamente). Cuando correlacionamos los valores de VO2max obtenidos en ambos tests, observamos una fuerte correlacin (r = 0,72). En conclusin, los tests de medida indirecta presentaron buena aceptacin para los atletas de futsal, teniendo en vista la alta correlacin con los tests de medida directa, el bajo costo de su aplicacin y el apercibimiento de las informaciones importantes que puedem auxiliar la prescricin de el no acompaamiento del entrenamiento. Abstract in english The importance of the morphofunctional qualities to greater efficiency in sports has increased the interest on the improvement on the physical fitness levels of athletes. However, not many studies on the physiological variables of indoor soccer are available in the world scientific literature. Thus, [...] the objective of this work was to verify the existence of correlation between the direct and indirect VO2max measurement tests in indoor soccer players. Thirteen indoor soccer players with age of 18.6 1.9 years, height of 177.1 3.5 cm, weight of 68.5 9.5 kg and body mass index (BMI) of 21.7 2.3 kg/m were analyzed. For the direct VO2max measurement, the computerized ergospirometric system was us

  9. Flujos de biomasa y estructura de un ecosistema de surgencia tropical en La Guajira, Caribe colombiano

    Scientific Electronic Library Online (English)

    Maria Isabel, Criales-Hernndez; Camilo, B. Garca; Matthias, Wolff.

    2006-12-01

    Full Text Available La Guajira es un ecosistema de surgencia explotado en la costa del Caribe colombiano. Con el propsito de integrar la informacin disponible sobre el sistema se construy un modelo trfico de 27 grupos funcionales usando el programa Ecopath 5.0 Beta. Se obtuvo una base cuantitativa para compararlo c [...] on otros sistemas de surgencia. La Guajira presenta una biomasa total de 68 t/km/ao, la produccin primaria neta del sistema es de 1 248.51 t/km/ao y las transferencias totales del sistema son de 3 275 t/km/ao, lo que indica un ecosistema con una surgencia moderada comparada con otros sitios. Las mayores transferencias de energa se dan del nivel trfico I-II (68.93 %), aunque existe una importante proporcin de flujos al detritus (32 %). Los resultados en los atributos de madurez del sistema sugieren que La Guajira es un ecosistema inmaduro debido a que la relacin P/R excede a 1 y est en desarrollo debido a la baja ascendencia (33.7 %) y alta capacidad de desarrollo (66.3 %) como ocurre con otras surgencias donde se presentan valores de ascendencia entre 20 % y 35 %. Aunque los datos bsicos de entrada en el modelo fueron buenos, gracias a las investigaciones que se han elaborado entre 1995 y 2000, existen algunos grupos donde no se encuentra an informacin adecuada; especialmente en los valores de biomasa del fitoplancton, invertebrados, bagres, peces depredadores pelgicos, as como estimaciones de produccin en invertebrados, peces depredadores pelgicos y peces pequeos pelgicos. No existe una cuantificacin de las poblaciones de mamferos y aves en el rea de estudio, los cuales constituyen depredadores superiores y hacen parte esencial en sistemas de surgencia Abstract in english Biomass flow and structure of a tropical upwelling ecosystem in La Guajira, Colombian Caribbean. La Guajira is an exploited tropical upwelling ecosystem in the Colombian Caribbean coast. A trophic model of 27 functional groups was constructed using the ECOPATH 5.0 Beta software to integrate the avai [...] lable information on the ecosystem. The model allowed a comparison with other trophic flow models of upwelling ecosystems. Total system biomass (68 t/km/year), net system production (1248.5 t/km/year), and total system throughput (3 275 t/km/year) make La Guajira moderate when compared with other systems. The largest amount of energy throughput is achieved from trophic level I to II (68.93 %), although an important proportion of the total flow originates from detritus (32 %). The production/respiration ratio exceeds 1, suggesting that La Guajira is an immature ecosystem and is in development, as determined by its low ascendency (33.7 %) and high development capacity (66.3 %), similar to other upwellings that have values of ascendency between 20 % and 35 %. Although the basic input data were good and covered 1995 to 2000, appropriate information is still not available on some trophic groups such as biomass (for phytoplankton, invertebrates, catfishes and pelagic predator fishes), secondary production data (invertebrates, pelagic predator fishes, and small pelagic fishes), and seabird and mammal populations, which are top trophic levels and an essential part of upwelling ecosystems. Rev. Biol. Trop. 54 (4): 1257-1282. Epub 2006 Dec. 15

  10. Relaciones longitud-biomasa en macroinvertebrados bentnicos de un arroyo serrano del sur de Crdoba, Argentina

    Scientific Electronic Library Online (English)

    Cristina, Gualdoni; Patricio W., French; Ana M., Oberto.

    2013-12-01

    Full Text Available Los mtodos ms utilizados para la determinacin indirecta de la biomasa de invertebrados se basan en ecuaciones matemticas que relacionan dimensiones lineales del cuerpo y el peso del organismo. Sin embargo, estas relaciones presentan variaciones que dependen de las condiciones biticas y fisicoqu [...] micas de cada ambiente particular. El propsito de este estudio fue determinar las ecuaciones que permitan estimar la relacin entre la talla y el peso de macroinvertebrados bentnicos del arroyo Achiras, situado en el sudoeste de la provincia de Crdoba (Argentina). El bentos se colect mediante redes de Surber, con una frecuencia estacional (otoo, invierno, primavera y verano) entre 2006 y 2007. Se midi la longitud corporal y se registr el peso seco de organismos de los grupos taxonmicos ms representados y se calcularon las ecuaciones de regresin que mejor explicaran la relacin entre ambas variables. Se evaluaron tres modelos, lineal, potencial y exponencial, y se seleccion la expresin que asociara mejor las variables. Se estimaron ecuaciones para 24 taxones de macroinvertebrados (tres especies, 12 gneros, tres subfamilias, cuatro familias y dos rdenes). La mayora de las regresiones fueron altamente significativas y explicaron una gran proporcin de la variacin del peso seco. Las ecuaciones estimadas sugieren que para la mayora de los macroinvertebrados bentnicos del arroyo Achiras, la relacin entre talla y biomasa es alomtrica y puede ser explicada por un modelo potencial o exponencial, mientras que, solo para cuatro taxones la regresin lineal simple ajust mejor los valores de longitud y peso corporal. Los modelos de regresin aplicados a grupos con menor nivel taxonmico (familia y gnero) explicaron una mayor proporcin de la variacin del peso, respecto a las regresiones al nivel de orden. Adems se estimaron dos ecuaciones generales que se ajustaron al modelo potencial. En la mayora de los grupos taxonmicos analizados el valor de la pendiente fue menor a tres y el coeficiente de determinacin promedio fue de 0.77. Ambos parmetros se ubican dentro del rango de variacin de los resultados publicados para la fauna bentnica de otros ambientes lticos. Abstract in english Length-biomass relationships in benthic macroinvertebrates of a mountain stream of the south of Crdoba, Argentina: The methods used for indirect determination of invertebrates biomass are based on mathematical equations that relate body linear dimensions and weight of the organism. However, these r [...] elationships depend on biotic and physicochemical conditions of each particular environment. The aim of this study was to determine the equations to estimate the relationship between length and weight of benthic macroinvertebrate of Achiras stream, located in the southwest of Crdoba province (Argentina). The benthos was collected with Surber nets, with a seasonal occurrence (fall, winter, spring and summer), between 2006 and 2007. Body length and dry weight for the specimens of the more represented taxonomic groups were registered and the regression equations that best explain the relationship between the two variables were calculated. We evaluated three models, simple linear, potential and exponential, and we selected the better expression that associate the variables. Equations were estimated for 24 macroinvertebrates taxa (three species, 12 genera, three subfamilies, four families and two orders). Most regressions were highly significant and explain a large proportion of the variation of the dry weight. The estimated equations suggest that for most of the benthic macroinvertebrates of Achiras stream, the relationship between length and biomass is alometric and can be explained by a power or exponential model, while only for four taxa simple linear regression best ft length and body weight values. Regression models applied to lower level taxonomic groups (family and genus) explained a greater proportion of the variation in weight, with regard to the order le

  11. Update of the China-VO AstroCloud

    CERN Document Server

    Cui, Chenzhou; Xiao, Jian; He, Boliang; Li, Changhua; Fan, Dongwei; Wang, Chuanjun; Hong, Zhi; Li, Shanshan; Mi, Linying; Wan, Wanghui; Cao, Zihuang; Wang, Jiawei; Yin, Shucheng; Fan, Yufeng; Wang, Jianguo; Yang, Sisi; Ling, Yin; Zhang, Hailong; Chen, Junyi; Liu, Liang; Chen, Xiao

    2016-01-01

    As the cyber-infrastructure for Astronomical research from Chinese Virtual Observatory (China-VO) project, AstroCloud has been archived solid progresses during the last one year. Proposal management system and data access system are re-designed. Several new sub-systems are developed, including China-VO PaperData, AstroCloud Statics and Public channel. More data sets and application environments are integrated into the platform. LAMOST DR1, the largest astronomical spectrum archive was released to the public using the platform. The latest progresses will be introduced.

  12. Metodologa de diseo e implementacin de soluciones voIP

    Directory of Open Access Journals (Sweden)

    Wilson A. Bulla B.

    2012-12-01

    Full Text Available El presente documento ilustra metodolgicamente el diseo y la implementacin de una solucin VoIP, la cual integra la planta anloga (PBX con el modulo de PBX del Elastix (IP-PBX, por medio de un Gateway de VoIP. Con el producto de esta investigacin, desarrollada por el grupo INTEGRA, se permite el uso de nuevos servicios enfocados en el ptimo uso de las redes (telefona y datos usando servicios adicionales, como son: servidor de fax, servidor de mensajera instantnea, control y reporte detallado de llamadas, grabaciones y servicios adicionales como la recepcin de fax y buzn de mensajes al correo electrnico como archivos adjuntos.

  13. Lattice effects in HoVo3 single crystal

    International Nuclear Information System (INIS)

    We report the study of lattice effects in the Mott insulator HoVO3 performed by means of linear thermal expansion on a single crystal in the temperature range 10-290 K. The holmium orthovanadate HoVO3 reveals gradual orbital ordering (OO) below T OO=200 K and orders antiferromagnetically at T N=113 K. A first-order structural phase transition takes place at T S?38 K, which is probably accompanied by change of the OO type and hence the type of antiferromagnetic spin ordering

  14. Epitaxial Growth of VO$_{2}$ by Periodic Annealing

    OpenAIRE

    Tashman, J. W.; Lee, J.H.; Paik, H; Moyer, J. A.; Misra, R.; Mundy, J. A.; Spila, T.; Merz, T. A.; Schubert, J.; Muller, D. A.; Schiffer, P.; D. G. Schlom

    2013-01-01

    We report the growth of ultrathin VO$_{2}$ films on rutile TiO$_{2}$ (001) substrates via reactive molecular-beam epitaxy. The films were formed by the cyclical deposition of amorphous vanadium and its subsequent oxidation and transformation to VO$_{2}$ via solid-phase epitaxy. Significant metal-insulator transitions were observed in films as thin as 2.3 nm, where a resistance change {\\Delta}R/R of 25 was measured. Low angle annular dark field scanning transmission electron ...

  15. Infrared-sensitive electrochromic device based on VO2

    Science.gov (United States)

    Nakano, M.; Shibuya, K.; Ogawa, N.; Hatano, T.; Kawasaki, M.; Iwasa, Y.; Tokura, Y.

    2013-10-01

    The field-effect transistor (FET) provides an electrical switching function of current flowing through a channel surface by external voltage. Here, we report on a field-effect device that enables electrical switching of optical transmittance as well as conventional electrical current. We investigated optical properties of vanadium dioxide (VO2) thin film under the presence of electric field generated at the interface between VO2 and ionic liquid in a FET geometry, and found that the device exhibits clear electrochromic effect with large ON/OFF contrast only in the infrared region, potentially beneficial for energy-saving smart window applications as a voltage-tunable transparent heat-cutting filter.

  16. Lightweight security mechanism for PSTN-VoIP cooperation

    CERN Document Server

    Mazurczyk, W; Mazurczyk, Wojciech; Kotulski, Zbigniew

    2006-01-01

    In this paper we describe a new, lightweight security mechanism for PSTN-VoIP cooperation that is based on two information hiding techniques: digital watermarking and steganography. Proposed scheme is especially suitable for PSTN-IP-PSTN (toll-by-passing) scenario which nowadays is very popular application of IP Telephony systems. With the use of this mechanism we authenticate end-to-end transmitted voice between PSTN users. Additionally we improve IP part traffic security (both media stream and VoIP signalling messages). Exemplary scenario is presented for SIP signalling protocol along with SIP-T extension and H.248/Megaco protocol.

  17. Evaluacin de dos mtodos para la estimacin de biomasa arbrea a travs de datos Landsat TM en Jusnajab La Laguna, Chiapas, Mxico: estudio de caso

    Directory of Open Access Journals (Sweden)

    Jorge Escandn Caldern

    1999-01-01

    Full Text Available Se evaluaron dos mtodos para estimar biomasa arbrea con apoyo en sensores remotos (LANDSAT TM. El primer mtodo se realiz con base en una clasificacin supervisada multiespectral con seis bandas Se utilizaron tipos de vegetacin identificados a partir de la composicin de biomasa de os gneros dominantes y de la altura promedio estimada del dosel, habindose distinguido ocho clases de vegetacin. Se obtuvo una biomasa total de 1 073 x 10 3t (902 x 10 3t a 1 220 x 10 3t En el segundo mtodo se utilizaron ndices diferenciados de vegetacin (NDVI de las bandas TM4/TM3; TM4/TM5 y TM4/TM7. Se aplic un modelo de regresin que relaciona la biomasa promedio con los valores digitales (VD de los NDVI. El modelo exponencial fue el de mejor ajuste para los tres NDVl con una p 0.01. Los valores de los NVDl fueron TM4/ TM3. R2=0 611, TM4/TM5. R2=0.671 y TM4/TM7: R2=0.676. La biomasa total estimada con cada NDVI fue de 1 164 x 10 3t (490 x 10 3t a 2 409 x 10 3t para TM4/TM3; de 515x10 3t (331 x 10 3 t a 757 x 1 0 3 t p a r a TM/TM5 y d e 726 x 1 0 3 t ( 3 9 8 x 1 0 3 t a 1 210 x 10 3t para TM4/TM7. El resultado de la biomasa total calculada por el mtodo de clasificacin multiespectral, comparado con los valores estimados por el mtodo de ordenamiento exponencial, mostr mayor similitud con el valor mximo del NDVl que relaciona las bandas TM4/TM7 (de mayor ajuste estadstico y con el valor promedio del NDVl TM4/TM3 (de menor ajuste estadstico. Utilizando el NDVl TM4/TM5, todos los valores de biomasa resultaron ms bajos. De este estudio se concluye que es posible asociar razonablemente la biomasa de vegetacin arbolada de pino-encino y reservorios de carbono con los ndices de vegetacin. A travs del uso de sensores remotos se podran predecir cambios de biomasa en escalas temporales y espaciales.

  18. Bu? zmenou, ktor chce vo svete vidie?

    Directory of Open Access Journals (Sweden)

    Peter Ma?o

    2011-12-01

    Full Text Available Reklama primla tchto ?ud nah?a? sa za autami a atami, ktor nepotrebuj. Genercie pracuj v zamestnaniach, ktor neznaj, len aby si mohli kpi? to, ?o v skuto?nosti nepotrebuj. A tak sme sa ocitli v situcii, ke? nevlastnme veci, ale veci vlastnia ns, (Klub bitkrov, 1999. Od svitu ?udstva je kad spolo?nos? charakteristick aplikovanm jedine?nej stratgie preitia vzh?adom na okolit prostredie a okolit spolo?nosti. Tieto stratgie sa lia predovetkm svojm dosahom na ivotn prostredie a na ?ud, ktor v ?om ij. Hlavne za obdobie poslednch 10 000 rokov, teda pribline od db prvej domestikcie rastln a zvierat, sa ve?a stratgi uberalo nie ve?mi priaznivm smerom, ?o dokazuj nelichotiv tatistiky ?udskch obet a vy?erpanch ekosystmov. ia?, tento trend sa neustle stup?uje a jeho najv?m vyvrcholenm je prve s?asnos?. Ak sa bavme o nejakom civiliza?nom pokroku a neustlom rozvoji, toto je potom jeho temn strnka, ktor je ale ?asto ignorovan a prehliadan. ?o teda urobi? pre to, aby bol vvoj udrate?n?

  19. Reproducibility of maximum aerobic power (VO2max among soccer players using a modified heck protocol Reprodutibilidade da potncia aerbia mxima (VO2max em jogadores de futebol utilizando o protocolo de heck modificado

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Santos-Silva

    2007-01-01

    Full Text Available OBJECTIVE: To determine the degree of reproducibility of maximum oxygen consumption (VO2max among soccer players, using a modified Heck protocol. METHODS: 2 evaluations with an interval of 15 days between them were performed on 11 male soccer players. All the players were at a high performance level; they were training for an average of 10 hours per week, totaling 5 times a week. When they were evaluated, they were in the middle of the competitive season, playing 1 match per week. The soccer players were evaluated on an ergometric treadmill with velocity increments of 1.2 km.h-1 every 2 minutes and a fixed inclination of 3% during the test. VO2max was measured directly using a breath-by-breath metabolic gas analyzer. RESULTS: The maximum running speed and VO2max attained in the 2 tests were, respectively: (15.6 1.1 vs. 15.7 1.2 km.h-1; [P = .78] and (54.5 3.9 vs. 55.2 4.4 ml.kg-1.min-1; [P = .88]. There was high and significant correlation of VO2max between the 2 tests with a 15-day interval between them [r = 0.97; P OBJETIVO: Determinar o grau de reprodutibilidade do consumo mximo de oxignio (VO2max em jogadores de futebol utilizando o protocolo de Heck modificado. MTODOS: Foram avaliados por duas vezes, com intervalo de 15 dias entre os testes, 11 futebolistas masculinos. Todos eram de alto nvel, treinavam em mdia 10 horas por semana subdivididos em treinamentos fsicos, tcnicos, tticos e jogos competitivos, totalizando cinco vezes por semana e na fase em que foram avaliados se encontravam em pleno perodo competitivo realizando um jogo por semana. Os futebolistas foram avaliados em esteira ergomtrica (1,2 km.h-1 a cada dois minutos e inclinao fixa durante o teste em 3%. O VO2max foi medido diretamente utilizando analisador metablico de anlise de gases expirados respirao-a-respirao. RESULTADOS: A velocidade mxima de corrida e o VO2max atingido nos dois testes foram respectivamente: (15,6 1,1 vs. 15,7 1,2 km.h-1; [p = 0,78] e (54,5 3,9 vs. 55,2 4,4 ml.kg-1.min-1; [P = 0,88]. Houve correlao significante e alta do VO2max entre os dois testes aps 15 dias de intervalo [r = 0,97; P< 0,001]. CONCLUSO: O protocolo de Heck modificado foi reprodutvel e o intervalo de quinze dias entre os testes ergoespiromtricos no foi suficiente para modificar significativamente o VO2max dos jogadores de futebol.

  20. Biomasa fngica y bacteriana como indicadoras del secuestro de C en suelos de sabanas sustituidos por pinares en Uverito, Venezuela

    Scientific Electronic Library Online (English)

    Magalis, Zabala; Yrma, Gmez.

    2010-09-01

    Full Text Available Cualquier transformacin de un ecosistema natural a un sistema agrcola o forestal conduce a una modificacin importante no slo del pool del carbono total, sino tambin del carbono asociado con la biomasa microbiana. Su cuantificacin es importante en la determinacin del impacto de las prcticas a [...] grcolas y el cambio de uso de la tierra sobre la calidad del suelo. El objetivo de este estudio fue determinar, a travs del mtodo de inhibicin selectiva, la biomasa fngica y bacteriana y la relacin (H:B) en suelos de sabana nativa sustituidos por pinares (Pinus caribaea var. hondurensis), para establecer si stos parmetros son indicadores sensibles de cambios en el contenido de carbono en suelos de Uverito, Venezuela. La relacin de aditividad del inhibidor (RAI) y la inhibicin total por efecto combinado del inhibidor (ITC) se llevaron a cabo para determinar, si los inhibidores microbianos tuvieron actividad sobre otros organismos para los cuales stos no estaban destinados. La cuantificacin de la biomasa fngica y bacteriana se llev a cabo mediante el uso de la cycloheximida como inhibidor fngico, y la estreptomicina y el cloranfenicol como inhibidores bacterianos. Esta investigacin evidencia que este cambio de uso de la tierra ejerci un efecto significativo sobre la biomasa microbiana del suelo, y muestra que en el sistema de pinares existe una dominancia del componente fngico, en contraste con la sabana nativa, en la cual domina la biomasa bacteriana. La sustitucin de la sabana nativa por plantaciones de pino en Uverito, promueve un mayor secuestro del carbono en el suelo. Los valores de la relacin de aditividad del inhibidor (RAI) tanto para la sabana nativa como para el sistema de pinares, resultaron ambos >1.0. La inhibicin total combinada (ITC) result menor en el sistema de pinares; a partir de lo cual, es posible inferir que una elevada proporcin de la biomasa microbiana fue afectada por la combinacin de los inhibidores. Abstract in english Fungal and bacterial biomass as indicators of soil C sequestration in savannas soils substituted by pine plantations. A transformation of any natural ecosystem to an agricultural or forest system leads to an important soil modification, not only in the total carbon pool, but also in the carbon assoc [...] iated to the microbial biomass. This way, carbon quantification on soil quality is important for the determination of impacts of agricultural practices and land use changes. The aim of this study was to the determine, through the selective inhibition technique, the fungal and bacterial biomass, and fungal-to-bacterial ratio (F:B) in pine plantations (Pinus caribaea var. hondurensis), to establish if these parameters are sensible indicators of changes in the carbon content in Uverito soils (Venezuela). Furthermore, the inhibitor additivity ratio (IAR) and total combined inhibition (TCI) were carried out to determine if the antibiotics caused non-target inhibition. The quantification of fungal and bacterial biomass was carried out by using of cyloheximide as fungal inhibitor, and streptomycin and chloranphenicol as specific bacterial inhibitors. This research evidences that this land use change exerted a significant effect on soil microbial biomass, and shows that in pine plantations there is a dominance of the fungal component, in contrast to the native savanna, in which the bacterial biomass dominates. The substitution of native savanna by pine plantation in Uverito promotes a major soil carbon sequestration. The values of the inhibitor additivity ratio (IAR) as for native savanna as pine system, were both>1.0. The total combined inhibition (TCI) was smaller in the pine systems, from which it is possible to infer that a high proportion of microbial biomass was affected by the combination of the inhibitors. Rev. Biol. Trop. 58 (3): 977-989. Epub 2010 September 01.

  1. Enfermedad pulmonar obstructiva crnica por exposicin al humo de biomasa / Chronic obstructive pulmonary disease by biomass smoke exposure

    Scientific Electronic Library Online (English)

    Matas, Lopez; Nicole, Mongilardi; William, Checkley.

    2014-03-01

    Full Text Available En este artculo se discute la relacin existente entre la enfermedad pulmonar obstructiva crnica (EPOC) y el humo de biomasa. Ms de la mitad de la poblacin utiliza biomasa como combustible principal, sobre todo en reas rurales y en pases en vas de desarrollo donde su uso llega hasta el 80%. L [...] a inhalacin del humo de biomasa crea un estado inflamatorio crnico, que se acompaa de una activacin de metaloproteinasas y una reduccin de la movilidad mucociliar. Esto podra explicar la gran asociacin existente entre la exposicin a biomasa y EPOC, revelada por estudios observacionales y epidemiolgicos provenientes de pases en vas de desarrollo y de pases desarrollados. En esta revisin exploramos tambin las diferencias entre la EPOC causada por tabaco y por biomasa, y encontramos que, a pesar de las diferencias fisiopatolgicas, la mayora de las caractersticas clnicas, calidad de vida y mortalidad fueron parecidas. En los ltimos diez aos se han realizado intervenciones para disminuir la exposicin a biomasa mediante el uso de cocinas mejoradas y combustibles limpios, sin embargo, estas estrategias todava no han sido exitosas debido a su incapacidad para reducir los niveles de contaminacin a niveles recomendados por la Organizacin Mundial de la Salud, y por su falta de uso. Por lo tanto, hay una necesidad urgente de ensayos de campo aleatorios, cuidadosamente realizados, para determinar la verdadera gama de reducciones de contaminacin potencialmente alcanzables, la probabilidad de su uso y los beneficios a largo plazo en la reduccin de la gran carga mundial de EPOC Abstract in english In this article, the relationship between chronic obstructive pulmonary disease (COPD) and biomass smoke will be discussed. More than half of the world population uses biomass for fuel, especially in rural areas and in developing countries where usage reaches 80%. Biomass smoke inhalation creates an [...] inflammatory chronic state, which is accompanied by metalloproteinases activation and mucociliary mobility reduction. This could explain the existing association between biomass exposure and COPD, revealed by observational and epidemiological studies from developing and developed countries. In this review, the differences between COPD caused by tobacco and biomass were explored. It was found that despite the pathophysiological differences, most of the clinical characteristics, quality of life and mortality were similar. In the last ten years there have been interventions to reduce the biomass smoke exposure by using improved stoves and cleaner fuels. However, these strategies have not yet been successful due to inability to reduce contamination levels to those recommended by the World Health Organization as well as due to the lack of use. Therefore, there is an urgent need for carefully conducted, randomized field trials to determine the actual range of potentially reachable contamination reductions, the probability of use and the long term benefits of reducing the global burden of COPD

  2. Enfermedad pulmonar obstructiva crnica por exposicin al humo de biomasa / Chronic obstructive pulmonary disease by biomass smoke exposure

    Scientific Electronic Library Online (English)

    Matas, Lopez; Nicole, Mongilardi; William, Checkley.

    2014-01-01

    Full Text Available En este artculo se discute la relacin existente entre la enfermedad pulmonar obstructiva crnica (EPOC) y el humo de biomasa. Ms de la mitad de la poblacin utiliza biomasa como combustible principal, sobre todo en reas rurales y en pases en vas de desarrollo donde su uso llega hasta el 80%. L [...] a inhalacin del humo de biomasa crea un estado inflamatorio crnico, que se acompaa de una activacin de metaloproteinasas y una reduccin de la movilidad mucociliar. Esto podra explicar la gran asociacin existente entre la exposicin a biomasa y EPOC, revelada por estudios observacionales y epidemiolgicos provenientes de pases en vas de desarrollo y de pases desarrollados. En esta revisin exploramos tambin las diferencias entre la EPOC causada por tabaco y por biomasa, y encontramos que, a pesar de las diferencias fisiopatolgicas, la mayora de las caractersticas clnicas, calidad de vida y mortalidad fueron parecidas. En los ltimos diez aos se han realizado intervenciones para disminuir la exposicin a biomasa mediante el uso de cocinas mejoradas y combustibles limpios, sin embargo, estas estrategias todava no han sido exitosas debido a su incapacidad para reducir los niveles de contaminacin a niveles recomendados por la Organizacin Mundial de la Salud, y por su falta de uso. Por lo tanto, hay una necesidad urgente de ensayos de campo aleatorios, cuidadosamente realizados, para determinar la verdadera gama de reducciones de contaminacin potencialmente alcanzables, la probabilidad de su uso y los beneficios a largo plazo en la reduccin de la gran carga mundial de EPOC Abstract in english In this article, the relationship between chronic obstructive pulmonary disease (COPD) and biomass smoke will be discussed. More than half of the world population uses biomass for fuel, especially in rural areas and in developing countries where usage reaches 80%. Biomass smoke inhalation creates an [...] inflammatory chronic state, which is accompanied by metalloproteinases activation and mucociliary mobility reduction. This could explain the existing association between biomass exposure and COPD, revealed by observational and epidemiological studies from developing and developed countries. In this review, the differences between COPD caused by tobacco and biomass were explored. It was found that despite the pathophysiological differences, most of the clinical characteristics, quality of life and mortality were similar. In the last ten years there have been interventions to reduce the biomass smoke exposure by using improved stoves and cleaner fuels. However, these strategies have not yet been successful due to inability to reduce contamination levels to those recommended by the World Health Organization as well as due to the lack of use. Therefore, there is an urgent need for carefully conducted, randomized field trials to determine the actual range of potentially reachable contamination reductions, the probability of use and the long term benefits of reducing the global burden of COPD

  3. Urchin-like m-LaVO{sub 4} and m-LaVO{sub 4}/Ag microspheres: Synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Limiao, E-mail: chenlimiao@csu.edu.cn [School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 (China); College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Wu, Min; Wang, Dan; Zhou, Le; Yu, Na; Zhang, Peisen; Huang, Jianhan [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Liu, Xiaohe, E-mail: liuxh@csu.edu.cn [School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 (China); Qiu, Guanzhou [School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 (China)

    2014-12-15

    The semiconductor nanostructures decorated with noble metals have attracted increasing attention due to their interesting physical and chemical properties. In this work, urchin-like monoclinic (m-) LaVO{sub 4} microspheres were prepared by a hydrothermal method and used as a template to fabricate Ag nanoparticle-decorated m-LaVO{sub 4} composites. The morphology and structure were characterized by transmission electron microscope, high-resolution transmission electron microscope, scanning electron microscope, and energy-dispersive X-ray. It was found that Ag nanoparticles with narrow size distribution were uniformly loaded on urchin-like m-LaVO{sub 4} microspheres, and the resulted composite microspheres showed distinct surface plasmon absorption band compared to pure m-LaVO{sub 4} microspheres. Photocatalytic activities of as-prepared samples were examined by studying the degradation of methyl orange solutions under visible-light irradiation (> 400 nm). Results clearly showed that urchin-like m-LaVO{sub 4}/Ag microspheres possess much higher photocatalytic activity than pure m-LaVO{sub 4} microspheres and P25. - Highlights: m-LaVO{sub 4}/Ag composites microspheres were fabricated by a hydrothermal method. m-LaVO{sub 4} microspheres show higher photocatalytic activity than m-LaVO{sub 4} microspheres. m-LaVO{sub 4}/Ag microspheres exhibit a good stability.

  4. Evidence of cardiac functional reserve upon exhaustion during incremental exercise to determine VO2max

    OpenAIRE

    Elliott, Adrian; Skowno, Justin; Prabhu, Mahesh; Noakes, Timothy; Ansley, Les

    2015-01-01

    Background - There remains considerable debate regarding the limiting factor(s) for maximal oxygen uptake (VO2max). Previous studies have shown that the central circulation may be the primary limiting factor for VO2max and that cardiac work increases beyond VO2max. Aim - We sought to evaluate whether the work of the heart limits VO2max during upright incremental cycle exercise to exhaustion. Methods - Eight trained men completed two incremental exercise trials, each terminating with e...

  5. Oxygen pressure dependent VO2 crystal film preparation and the interfacial epitaxial growth study

    International Nuclear Information System (INIS)

    High quality VO2 crystal films have been prepared on sapphire substrates by pulsed laser deposition method and the effects of oxygen pressure on the crystal phase structure are investigated. Results indicate that the phases and microstructures of VO2 films are strongly sensitive to oxygen pressure. High oxygen pressure tends to form coarse B-VO2 nanocrystals while low pressure favors a flat M1-VO2 film epitaxial growth. X-ray diffraction ?-scan patterns confirm the [020] epitaxial growth orientation of the M1-VO2 film and the in-plane lattice epitaxial relationship at the interface is also examined. Raman spectra indicate that M1-VO2 phase has much stronger Raman scattering modes than B-VO2, and the clear phonon modes further confirm the idea stoichiometry of VO2 crystal film. Infrared transmittance spectra as the function of temperature are recorded and the results show that M1-VO2 crystal films undergo a distinct infrared transmittance variation across metal insulator transition boundary, while B-VO2 exhibits negligible thermochromic switching properties in the temperature range concerned. The pronounced phase transition behavior of the M1-VO2 crystal film makes it a promising candidate for optical filter/switch and smart window applications in the future. - Highlights: ? High quality VO2 films with different phase structures were obtained by PLD method. ? High oxygen pressure tends to form B-VO2 while low pressure favors M1-VO2 film. ? ?-scan XRD confirms the [020] epitaxial growth orientation of the M1-VO2 film. ? The epitaxial relationship is explained based on domain matching theory. ? M1-VO2 film shows excellent optical property in infrared range.

  6. Efecto de la salinidad sobre el aceite esencial y la biomasa de dos genotipos de organo (Origanum spp. cultivados en invernculo

    Directory of Open Access Journals (Sweden)

    Collado, C.E.

    2012-01-01

    Full Text Available In arid or semi-arid zones, where the quality and/or quantity of water available for watering is inadequate to eliminate the excess of soluble salts, the soil salinity could affect the yield and/or quality of oregano crops. The objective of this study is to evaluate the productivity of biomass and essential oils of two genotypes of oregano when exposed to five different levels of water salinity. An experiment was carried out in pots with a completely random design and four replications. The plants were grown in a greenhouse in sandy-loam soil. They were irrigated with water salinized with NaCl, CaCl2 and MgCl2 with levels of electric conductivity (EC of 2, 4, 6 and 8 dSm-1 and a control of 0.35 dSm-1 (no salt added. After 90 days the plants were harvested, and the biomass of the different organs was measured, as well as the yield and concentration of the essential oils in the leaves. The genotype Origanum vulgare L. sp. viridulum yielded a 40 % or more leaves and more than double the essential oil than Origanum x majoricum Cambess for the majority of the EC measurements. If these results are similar to field experiments, the use of O. vulgare with respect to O. x majoricum would be recommendable for both leaf and essential oil yields with salinity of up to 6 dSm-1, in the first harvest.------------------------------------------------------------------------------------------ En zonas ridas o semiridas donde la calidad y/o cantidad de agua de riego es inadecuada para eliminar el exceso de sales solubles, la salinidad podra afectar el rendimiento y/o calidad de los cultivos de organo. El objetivo de este trabajo fue evaluar la productividad en biomasa y aceite esencial de dos genotipos de organo ante cinco niveles de salinidad. Se realiz un experimento en macetas con un DCA en arreglo factorial y cuatro repeticiones. Las plantas se cultivaron bajo invernculo, en un suelo de textura franco-arenosa, regndose con agua salinizada con NaCl, CaCl2 yMgCl2 con niveles de conductividad elctrica (CE de 2, 4, 6 y 8 dSm-1 y un testigo 0,35 dSm-1 (sin agregado de sal. A los 90 das las plantas fueron cosechadas determinndose: la biomasa de los diferentes rganos y rendimiento y concentracin del aceite esencial en hojas. El genotipo Origanum vulgare L. sp. viridulum rindi 40 % o ms de hojas y ms del doble de aceite esencial que Origanum x majoricum Cambess para la mayora de las condiciones de CE. Si estos resultados se mantienen en ensayos a campo, el uso de O. vulgare con respecto a O. x majoricum sera recomendable tanto para rendimiento de hojas como de aceite, con salinidades de hasta 6 dSm-1, en la primer cosecha.

  7. DISTRIBUCIÓN DE BIOMASA Y ACUMULACIÓN DE PLOMO EN CALABACITA (Cucurbita pepo L. CULTIVADA EN SUELO CONTAMINADO

    Directory of Open Access Journals (Sweden)

    Floriberto Solis-Mendoza

    2012-01-01

    Full Text Available Se estudió el efecto del suelo contaminado con plomo en el híbrido experimental de calabacita (Cucurbita pepo L. denominado 'Termo'. Se cultivó calabacita en bolsas negras de polietileno, a cielo abierto. Se evaluaron las variables distribución de la producción de biomasa, altura de planta, contenido de clorofila y acumulación de plomo en raíz, tallo, hoja, flor y fruto. Los tratamientos fueron 0, 65, 300 y 1000 ppm de plomo aplicado al suelo a través de Pb(NO32. Se utilizó un diseño experimental de bloques completos al azar con seis repeticiones, y la unidad experimental fue una bolsa negra de polietileno con dos plantas. Las evaluaciones se hicieron 50 días después del trasplante para altura de planta y contenido de clorofila, y a los 52 días para peso fresco, peso seco y acumulación de plomo. Se observó que la altura de planta fue significativamente menor cuando se aplicó plomo a cualquier dosis. También se observó que la mayor acumulación de biomasa en raíz y tallo fue producida con la dosis 300 ppm y en fruto con 65 ppm de plomo, en tanto que la biomasa total y las unidades SPAD (clorofila no resultaron afectadas. De las estructuras comestibles, la flor presentó una mayor acumulación del metal que el fruto. A bajas dosis de plomo, la flor fue la estructura que más lo acumuló. Esto sugiere que es conveniente evaluar el contenido de metales pesados en productos agrícolas para consumo humano, aun cuando provengan de suelos contaminados sin intención.

  8. EVALUACIN DE LA BIOMASA Y MANEJO DE Lemna gibba (LENTEJA DE AGUA EN LA BAHA INTERIOR DEL LAGO TITICACA, PUNO

    Directory of Open Access Journals (Sweden)

    ngel Canales-Gutirrez

    2010-01-01

    Full Text Available Uno de los mayores problemas que enfrenta la ciudad de Puno es la presencia de la lenteja de agua (Lemna gibba en la baha interior del Lago Titicaca, debido al proceso de eutrofizacin que sufre a causa del mal tratamiento de las aguas residuales de la ciudad de Puno. Muchas de las estrategias planteadas hasta ahora no han dado resultados positivos en la reduccin de la biomasa de Lemna gibba, debido a que estos planes estn direccionados a la exterminacin de este organismo. En lugar de ello se debe pensar en la forma ms sostenible de hacer uso de la lenteja. Es por eso que los objetivos fueron: (a estimar la biomasa (kg/m de lenteja de agua de la baha interior del lago Titicaca y, (b plantear una estrategia de manejo de la lenteja de agua de la baha interior del lago Titicaca. El promedio de la biomasa de la lenteja de agua en la baha interior fue de 6.94 kg/m, mientras que los promedios de pH y temperatura del agua fueron de 6.3 y 13.8C, respectivamente. Esto prueba la eficacia de este organismo para crecer en condiciones difciles (adems hay altos niveles de N, P y metales pesados, por lo que su manejo puede ser una alternativa para disminuir el proceso de eutrofizacin del lago. Las estrategias de manejo de lenteja estuvieron enmarcadas dentro de un plano social, econmico y ambiental, lo que permite su sostenibilidad en beneficio de la poblacin de Puno y del ecosistema del lago Titicaca.

  9. COMPETENCIA POR SUSTRATO DURANTE EL DESARROLLO DE BIOMASA SULFATORREDUCTORA A PARTIR DE UN LODO METANOGNICO EN UN REACTOR UASB

    Directory of Open Access Journals (Sweden)

    Marisol GALLEGOS-GARCA

    2010-01-01

    Full Text Available En este trabajo se estudi la competencia entre microorganismos metanognicos y sulfatorreductores utilizando un reactor anaerobio de lecho de lodo granular con flujo ascendente (UASB a escala laboratorio, el cual fue usado para el enriquecimiento de biomasa sulfatorreductora a partir de un lodo granular de origen metanognico. El reactor se aliment con una mezcla de etanol y acetato, la carga orgnica se increment de 0.5 a 2 g de demanda qumica de oxgeno (DQO/L-d a pH de 7.0. El consumo de DQO fue mayor a 90 % y la alcalinidad producida por la oxidacin del sustrato increment el pH en el efluente hasta 8.0. A partir de los 50 das de operacin, el reactor se aliment con lactato y sulfato para promover la sulfatorreduccin. La carga orgnica se aument de 1 a 3 g DQO/L-d con una relacin DQO/Sulfato de 0.67 a un tiempo de retencin hidrulico de un da. A los 194 das de operacin del reactor el mximo consumo de DQO y sulfato obtenido fue de 94 y 22 %, respectivamente. La concentracin total del sulfuro alcanzada fue de 310 mg S2-/L y la actividad sulfatorreductora de la biomasa fue de 0.29 g DQO-H2S/g SSV-d, lo que mostr el desarrollo de biomasa sulfatorreductora. La actividad metanognica que se obtuvo fue de 0.35 g DQO-CH4/g SSV-d, estos resultados mostraron que los organismos metanognicos no fueron desplazados por las bacterias sulfatorreductoras, coexistiendo ambos tipos de microorganismos en el lodo granular anaerobio al final de la operacin del reactor.

  10. Dinmica del bosque, incorporacin y almacenamiento de biomasa y carbono en el Parque Nacional Noel Kempff Mercado

    Directory of Open Access Journals (Sweden)

    Alejandro Araujo Murakami

    2006-07-01

    Full Text Available El presente estudio se realiz en dos reas permanentes de investigacin, cada una compuesta por dos parcelas permanentes de medicin, una en un bosque hmedo siempre verde (BHSV y la otra en un bosque seco semideciduo (BSS. Para conocer la dinmica en ambos bosques se calcul la mortalidad anual en funcin al nmero de individuos, la cual es de 2.09% ao en el BHSV y de 2.94% en el BSS y en funcin al rea basal, es de 1.59% en el BHSV y 3.76% en el BSS. Este ltimo valor determin una edad de cohorte de 523 aos en el BHSV y de 164 aos en el BSS. Igualmente se determin el incremento peridico anual diamtrico (IPAD, que es de 0.23 cm/ao en el BHSV y de 0.43 cm/ao en el BSS; con estos ltimos se proyect el crecimiento a travs del mtodo de los tiempos de pasos y tiempos acumulados o tiempo necesario para que cada individuo de 10 cm alcance el tamao mximo, calculando 518 aos para el BHSV y 292 aos para el BSS. La biomasa y el carbono almacenado se estim a travs de funciones matemticas que tienen como variable independiente al rea basal, estimando 326 tn/ha de biomasa y 156 tn/ha de carbono en el BHSV y 260 tn/ha de biomasa y 125 tn/ha de carbono en el BSS. Tambin se estim la incorporacin de carbono por medio del cambio producido en el rea basal, resultando 1.65 tn/ha/ao en el BHSV y 0.44 tn/ha/ao en el BSS. La estructura de ambos tipos de bosque es constante, los individuos muertos y los ascendidos a la clase inmediata son remplazados por aquellos individuos reclutados que mantienen la estructura del bosque.

  11. Utilizacin del medio de cultivo UIT-A en la obtencin de biomasa para la identificacin bioqumica micobacteriana

    Directory of Open Access Journals (Sweden)

    LILIAN M. MEDEROS CUERVO

    1995-12-01

    Full Text Available Se compara el medio de cultivo slido UIT-A con el Lowenstein Jensen, para la obtencin de biomasa en el montaje del test bioqumico de identificacin de micobacterias "no tuberculosas" (MNT, con el objetivo de valorar la posibilidad de utilizacin como medio de cultivo para el montaje y anlisis de dichas pruebas bioqumicas. Los resultados obtenidos en los 2 medios de cultivo utilizados fueron iguales, por lo que se recomienda el uso del medio de cultivo UIT-A fundamentalmente para aquellas cepas con crecimiento pobre o escaso.

  12. BIOMASA, DENSIDAD Y COMPOSICION ZOOPLANCTONICA DE LA BAHIA DE MOCHIMA, VENEZUELA Zooplankton biomass, density and composition in Mochima Bay, Venezuela

    OpenAIRE

    Brightdoom Mrquez-Rojas; Baumar Marn; J.R Daz-Ramos; Luis Troccoli

    2008-01-01

    La biomasa, densidad y composicin del zooplancton de la baha de Mochima fueron estudiadas durante 1998. Las muestras fueron recolectadas mensualmente en la entrada de la baha (estacin A) y en la parte interna (estacin B) entre enero y diciembre de 1998. En cada estacin se realizaron calados oblicuos con una malla estndar de 300 micras y 0,25 m de dimetro de boca a 0-5 y 10-15 m y a una velocidad de dos nudos durante 10 min. El ndice de surgencia se calcul a partir de los datos de vi...

  13. GASIFICACIN DE BIOMASA PARA PRODUCCIN DE COMBUSTIBLES DE BAJO PODER CALORFICO Y SU UTILIZACIN EN GENERACIN DE POTENCIA Y CALOR

    Directory of Open Access Journals (Sweden)

    CARLOS AUGUSTO ESTRADA

    2004-01-01

    Full Text Available Gases combustibles con bajo poder calorfico (LCV generados durante la gasificacin de biomasa se prevn como combustibles alternativos para diferentes aplicaciones como son calderas, motores de combustin interna, quemadores y turbinas de gas [1]. Esta fuente alternativa de energa presenta varias dificultades en su utilizacin; entre otras, la necesidad de la adecuacin de un sistema eficiente de filtrado y la adaptacin de los sistemas de combustin para recibir un flujo de combustible ms elevado con propsito de generar el mismo calor[7].

  14. Evaluacin de los pretratamientos con cido sulfrico diluido y AFEX en la biomasa lignocelulsica del tipo pasto gigante Pennisetum Sp

    OpenAIRE

    Mateus Fontecha, Lady

    2011-01-01

    El objetivo de esta investigacin fue estudiar la efectividad del pretratamiento con cido sulfrico diluido y la explosin de fibras con solucin de amonaco (AFEX) sobre la biomasa lignocelulsica de Pennisetum sp en la hidrlisis de carbohidratos fermentables para la produccin de etanol. En el pretratamiento con cido sulfrico se estudio el efecto de la temperatura (110, 130, 150, 170 y 190 C) y la concentracin del cido [0,8; 1,2 y 2,0 % (p/p)], mientras que en el pretratamiento AFEX ...

  15. Abundancia y biomasa de macroinvertebrados edficos en la temporada lluviosa, en tres usos de la tierra, en los andes colombianos

    OpenAIRE

    Pardo Luis C

    2006-01-01

    COMPENDIO los usos evaluados fueron pastizal, cafetal y bosque secundario (Vereda Villa del Rosario, Aprox. 3 33' 16? Latitud Norte y 76 36' 01? Longitud Oeste, altitud 1.500 a 1.820m., precipitacin 960 a 1.050 mm/ao, 19.8 a 21.2 C) con la metodologa TSBF. Se implementaron tres monolitos por uso y cada uno se subdividi en cuatro estratos (hojarasca, 0-10 cm, 10-20 cm, y 20-30 cm), las variables densidad y biomasa por parcela y estrato se examinaron a travs de ANOVAS y P...

  16. Preparation and crystal structure of a new bismuth vanadate, Bi{sub 3.33}(VO{sub 4}){sub 2}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Kumada, N., E-mail: kumada@yamanashi.ac.jp [Department of Research Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Miyamae-cho 7-32, Kofu 400-8511 Japan (Japan); Takei, T.; Haramoto, R.; Yonesaki, Y.; Dong, Q.; Kinomura, N. [Department of Research Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Miyamae-cho 7-32, Kofu 400-8511 Japan (Japan); Nishimoto, S.; Kameshima, Y.; Miyake, M. [Department of Material and Energy Science, Graduate School of Environmental Science, Okayama University, Tsusima-Naka 3-3-1, Okayama 700-8530 Japan (Japan)

    2011-06-15

    Graphical abstract: Crystal structure of Bi{sub 3.33}(VO{sub 4}){sub 2}O{sub 2}. Solid lines indicate the unit cell. Highlights: {yields} We can prepare a new bismuth vanadate, Bi{sub 3.33}(VO{sub 4}){sub 2}O{sub 2} by hydrothermal reaction using a hydrated sodium bismuthate. {yields} We clarify that the crystal structure is composed by four bismuth atoms with the coordination number of 6 or 8 and two VO{sub 4} tetrahedra. {yields} This compound exhibited photocatalytic behavior for decomposition of phenol under visible light irradiation. -- Abstract: Single crystals of a new bismuth vanadate, Bi{sub 3.33}(VO{sub 4}){sub 2}O{sub 2} was prepared by hydrothermal reaction using a hydrated sodium bismuthate, NaBiO{sub 3}.nH{sub 2}O as one of the starting compounds. The crystal structure was determined by using single crystal X-ray diffraction data. This compound crystallizes in the triclinic space group P1{sup -bar} (no. 2) with a = 7.114(1), b = 7.844(2), c = 9.372(2) A, {alpha} = 106.090(7), {beta} = 94.468(7) and {gamma} = 112.506(8){sup o}, Z = 2 and the final R factors are R1 = 0.052 and wR2 = 0.14 for 2085 unique reflections. The crystal structure is composed by four bismuth atoms with the coordination number of 6 or 8 and two VO{sub 4} tetrahedra, and one of four bismuth atoms is statistically distributed in the splitting sites with the distance of 0.83 A. This compound exhibited photocatalytic behavior for decomposition of phenol under visible light irradiation and its activity was less than that of monoclinic BiVO{sub 4}.

  17. Estimation of VO2 Max: A Comparative Analysis of Five Exercise Tests.

    Science.gov (United States)

    Zwiren, Linda D.; And Others

    1991-01-01

    Thirty-eight healthy females measured maximal oxygen uptake (VO2max) on the cycle ergometer and treadmill to compare five exercise tests (run, walk, step, and two tests using heart-rate response on the bicycle ergometer) in predicting VO2max. Results indicate that walk and run tests are satisfactory predictors of VO2max in 30- to 39-year-old

  18. Componente lento da cintica do VO2: determinantes fisiolgicos e implicaes para o desempenho em exerccios aerbios / Slow component of VO2 kinetics: physiological determinants and implications for performance in aerobic exercises

    Scientific Electronic Library Online (English)

    Renato Aparecido Correa, Carita; Dalton Muller, Pessoa Filho; Luis Fabiano, Barbosa; Camila Coelho, Greco.

    Full Text Available A cintica do consumo de oxignio (VO2) e a resposta do lactato sanguneo durante o exerccio de carga constante em diferentes intensidades permitem caracterizar os domnios moderado, pesado e severo do exerccio. Em exerccio de intensidade constante, o perfil da resposta do VO2, analisada por ajus [...] tes exponenciais, apresenta as fases cardiodinmica, fundamental e lenta. A ocorrncia do componente lento (CL) tem sido associada a fatores como recrutamento de fibras do tipo II e acmulo de metablitos, como lactato, ons H+, fosfato inorgnico e ADP. O CL expressa uma reduo da eficincia muscular e tem sido associado menor tolerncia de exerccios aerbios de intensidade alta. O presente estudo teve por objetivo detalhar a fundamentao terica sobre sua ocorrncia, a influncia na tolerncia ao exerccio, bem como prover os diferentes procedimentos adotados em sua quantificao. Abstract in english Oxygen uptake (VO2) kinetics and blood lactate response during constant workload exercise at different intensities allow characterizing the moderate, heavy and severe exercise domains. In constant-intensity exercise, the VO2 response profile, analyzed by exponential fits, shows the cardiodynamic, fu [...] ndamental and slow phases. The occurrence of the slow component (SC) has been associated with factors such as the recruitment of type II fibers and the accumulation of metabolites such as lactate, ions H+, inorganic phosphate and adenosine diphosphate. The SC expresses a reduction of muscular efficiency and has been associated with lower tolerance to high-intensity aerobic exercise. The present study aimed to detail the theoretical framework of its occurrence and its influence on exercise tolerance, as well as providing the different procedures used in its quantification.

  19. Structure and magnetism of epitaxial PrVO3 films.

    Science.gov (United States)

    Copie, O; Rotella, H; Boullay, P; Morales, M; Pautrat, A; Janolin, P-E; Infante, I C; Pravathana, D; Lders, U; Prellier, W

    2013-12-11

    The interplay between charge, spin, orbital and lattice degrees of freedom in transition metal oxides has motivated extensive research aiming to understand the coupling phenomena in these multifunctional materials. Among them, rare earth vanadates are Mott insulators characterized by spin and orbital orderings strongly influenced by lattice distortions. Using epitaxial strain as a means to tailor the unit cell deformation, we report here on the first thin films of PrVO3 grown on (001)-oriented SrTiO3 substrate by pulsed laser deposition. An extensive structural characterization of the PrVO3 films, combining x-ray diffraction and high-resolution transmission electron microscopy studies, reveals the presence of oriented domains and a unit cell deformation tailored by the growth conditions. We have also investigated the physical properties of the PrVO3 films. We show that, while PrVO3 exhibits an insulating character, magnetic measurements indicate low-temperature hard-ferromagnetic behavior below 80K. We discuss these properties in view of the thin-film structure. PMID:24214665

  20. Improving Quality of VoIP over WiMAX

    Directory of Open Access Journals (Sweden)

    M.A. Mohamed

    2012-05-01

    Full Text Available Real-time services such as VoIP are becoming popular and are major revenue earners for network service providers. These services are no longer confined to the wired domain and are being extended over wireless networks. Although some of the existing wireless technologies can support some low-bandwidth applications, the bandwidth demands of many multimedia applications exceed the capacity of these technologies. The IEEE 802.16-based WiMAX promises to be one of the wireless access technologies capable of supporting very high bandwidth applications. In this paper, we exploit the rich set of flexible features offered at the medium access control (MAC layer of WiMAX for the construction and transmission of MAC protocol data units (MPDUs for supporting multiple VoIP streams. We discuss the quality of VoIP calls, usually given by R-score, with respect to the delay and loss of packets. We analysis the quality of service (QoS on long distance data transfer between two locations with VoIP over WiMAX will be performed. Performance of selected parameters will be done using the network simulator, OPNET Modeler 14.5 [1,2].

  1. Direct and continuous synthesis of VO2 nanoparticles

    Science.gov (United States)

    Powell, M. J.; Marchand, P.; Denis, C. J.; Bear, J. C.; Darr, J. A.; Parkin, I. P.

    2015-11-01

    Monoclinic VO2 nanoparticles are of interest due to the material's thermochromic properties, however, direct synthesis routes to VO2 nanoparticles are often inaccessible due to the high synthesis temperatures or long reaction times required. Herein, we present a two-step synthesis route for the preparation of monoclinic VO2 nanoparticles using Continuous Hydrothermal Flow Synthesis (CHFS) followed by a short post heat treatment step. A range of particle sizes, dependent on synthesis conditions, were produced from 50 to 200 nm by varying reaction temperatures and the residence times in the process. The nanoparticles were characterised by powder X-ray diffraction, Raman and UV/Vis spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The nanoparticles were highly crystalline with rod and sphere-like morphologies present in TEM micrographs, with the size of both the rod and spherical particles being highly dependent on both reaction temperature and residence time. SEM micrographs showed the surface of the powders produced from the CHFS process to be highly uniform. The samples were given a short post synthesis heat treatment to ensure that they were phase pure monoclinic VO2, which led to them exhibiting a large and reversible switch in optical properties (at near-IR wavelengths), which suggests that if such materials can be incorporated into coatings or in composites, they could be used for fenestration in architectural applications.

  2. Multi-VO support in IHEP's distributed computing environment

    Science.gov (United States)

    Yan, T.; Suo, B.; Zhao, X. H.; Zhang, X. M.; Ma, Z. T.; Yan, X. F.; Lin, T.; Deng, Z. Y.; Li, W. D.; Belov, S.; Pelevanyuk, I.; Zhemchugov, A.; Cai, H.

    2015-12-01

    Inspired by the success of BESDIRAC, the distributed computing environment based on DIRAC for BESIII experiment, several other experiments operated by Institute of High Energy Physics (IHEP), such as Circular Electron Positron Collider (CEPC), Jiangmen Underground Neutrino Observatory (JUNO), Large High Altitude Air Shower Observatory (LHAASO) and Hard X-ray Modulation Telescope (HXMT) etc, are willing to use DIRAC to integrate the geographically distributed computing resources available by their collaborations. In order to minimize manpower and hardware cost, we extended the BESDIRAC platform to support multi-VO scenario, instead of setting up a self-contained distributed computing environment for each VO. This makes DIRAC as a service for the community of those experiments. To support multi-VO, the system architecture of BESDIRAC is adjusted for scalability. The VOMS and DIRAC servers are reconfigured to manage users and groups belong to several VOs. A lightweight storage resource manager StoRM is employed as the central SE to integrate local and grid data. A frontend system is designed for user's massive job splitting, submission and management, with plugins to support new VOs. A monitoring and accounting system is also considered to easy the system administration and VO related resources usage accounting.

  3. Synthesis and characterization of FeVO{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Nithya, V.D. [Solid State Ionics and Energy Devices Laboratory, Department of Physics, Bharathiar University, Coimbatore 641 046, Tamil Nadu (India); Selvan, R. Kalai, E-mail: selvankram@buc.edu.in [Solid State Ionics and Energy Devices Laboratory, Department of Physics, Bharathiar University, Coimbatore 641 046, Tamil Nadu (India); Sanjeeviraja, C. [School of Physics, Alagappa University, Karaikudi 630 003, Tamil Nadu (India); Radheep, D. Mohan; Arumugam, S. [Centre for High Pressure Research, School of Physics, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu (India)

    2011-10-15

    Highlights: {yields} Simple co-precipitation method were employed for the synthesis of FeVO{sub 4}. {yields} The calcination temperature and the reaction time were optimized. {yields} The effect of surfactants on the structural, morphological and magnetic properties was studied. {yields} The shape of the particles changes due to the effect of surfactant. {yields} Enhancement of magnetic orderings on the addition of surfactant. -- Abstract: Iron vanadate (FeVO{sub 4}) nanoparticles were synthesized by simple co-precipitation method using various surfactants such as ethylene glycol, polyethylene glycol 200 and polyethylene glycol 400 as the structure directing agents. Systematic investigations on the structural, morphological and magnetic properties of the materials have been studied. The lattice constants of the triclinic structure of FeVO{sub 4} were calculated from the X-ray diffraction (XRD) analyses. The average grain size was estimated to be around 35 nm, which increased with increasing the calcination temperature. The stretching and bending vibrations of Fe-O were evaluated from the FT-IR spectra. Using VSM magnetometer, magnetic property was investigated through magnetic susceptibility and magnetization measurements. FeVO{sub 4} exhibits two magnetic ordering temperatures at T {approx} 20 K and 14 K, which is due to two different chemical environments of Fe ligands such as octahedral FeO{sub 6} and trigonal bipyramidal FeO{sub 5} in a six-column doubly bent chain, respectively.

  4. Upcoming Features of SPLAT-VO in Astroinformatics.

    Czech Academy of Sciences Publication Activity Database

    aloun, P.; Andrei?, D.; koda, Petr; Zelinka, I.

    Vol. 210. Cham : Springer, 2013, s. 475-486 ISBN 978-3-319-00541-6. ISSN 2194-5357. [Nostradamus 2013. Ostrava (CZ), 03.06.2013-05.06.2013] R&D Projects: GA ?R GA13-08195S Institutional support: RVO:67985815 Keywords : SPLAT-VO * spectrum analysis * SAMP Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  5. Determinacin de las reservas de carbono de la biomasa area, en diferentes sistemas de uso de la tierra en San Martn, Per

    Directory of Open Access Journals (Sweden)

    Tatiana Lapeyre

    2004-01-01

    Full Text Available Se determin la biomasa area en diferentes sistemas de uso de la tierra en la regin de San Martn-Per, con la finalidad de conocer el potencial de captura de carbono. Los sistemas de uso de la tierra evaluados fueron: Bosque primario, Bosque secundario de diferentes edades, sistemas agrcolas locales maz (Zea maiz, arroz (Oriza Sativa, pastos (Brachiaria y sistemas agroforestales con caf (Coffea arabica bajo sombra y cacao (Cacao sp.. Tambin se compar este potencial con otros sistemas de uso de la tierra de otras regiones del Per y se monitore la prdida de reservas de carbono despus del corte de la foresta y su reemplazo por cultivos. En cada uno de stos sistemas se establecieron al azar cinco transectos donde se evalu la biomasa arbrea. Dentro de stos transectos se establecieron cuadrados tambin al azar para cuantificar la biomasa herbcea y la biomasa de hojarasca. El carbono total en el bosque primario fue de 485 tm C ha-1, superando ampliamente las reservas del bosque secundario de 50 aos y de bosque descremado de 20 aos. Con relacin al bosque primario se observa una reduccin de reservas en ms de 50% del bosque secundario de 50 aos (234 tm C ha-1. El bosque descremado de 20 aos perdi ms del 80% de reservas (62 tm C ha-1. El nivel de reservas de carbono en la biomasa de hojarasca de los sistemas boscosos, no es significativo al compararlo con el total de las reservas de carbono de la biomasa area; sin embargo si es significativo para sistemas agroforestales. Los sistemas agroforestales secuestraron entre 19 a 47 tm C ha-1, dependiendo de la cantidad de especies forestales, tipo de cultivo, edad y tipo de suelo y recuperan el potencial de captura en forma productiva. Los sistemas agrcolas capturaron poco C (5 tm C ha-1, adems generan fugas de gases efecto invernadero (GEI cuando se usan agroqumicos y quema de rastrojos, entre otros.

  6. Anlisis de biomasa del vuelo de un rodal adulto de Pinus radiata Analysis of aboveground biomass in a mature stand of Pinus radiata

    Directory of Open Access Journals (Sweden)

    CLAUDIO MUOZ RIVEROS

    2005-12-01

    Full Text Available Se realiz un estudio de biomasa en rboles de Pinus radiata D. Don de 42 aos, obtenidos de un rodal ubicado entre las ciudades de Santa Juana y Nacimiento, VIII Regin, Chile. El rodal se diferenci en tres clases de copa: dominante, codominante e intermedio. En cada clase de copa se obtuvieron valores de biomasa para cada componente (madera, corteza, ramas, ramillas y acculas; la madera result ser el componente que ms aport a la biomasa total sobre el suelo (88,9%, seguido de la corteza (8,2% y ramas (1,5%. Con los valores de biomasa obtenidos, se ajustaron funciones de biomasa por componente, relacionando estos valores con variables del rbol; el dap (dimetro a la altura del pecho y el dbc (dimetro en la base de la copa viva fueron las variables que mostraron mayor correlacin con los valores de biomasa por componente y menores errores de estimacin.A study of biomass in Pinus radiata D. Don with 42 years old was made, the trees were obtained of a stand placed between the cities of Santa Juana and Nacimiento, VIII Region, Chile. Three classes of top were differentiated in the stand: dominant, codominant and intermediate. The value of the mass for each component (wood, bark, branches, branchlets and needle was obtained from each class of top; the wood resulted as the most important component in the total biomass of the tree (88.9%, then the bark (8.2% and branches (1.5%. Obtained the values of biomass, the function of biomass for each component was obtained, related this values with the variables of the tree; the variables that showed greater correlation with the values of biomass by component and minors estimation errors are dbh (breast height diameter and dbc (base of live crown diameter.

  7. Microstructure of orientation controlled VO2 thin films via ZnO buffer

    International Nuclear Information System (INIS)

    B-axis preferential oriented VO2 thin films were prepared on glass substrates via ZnO buffers by pulsed laser deposition. In order to explore the relationship between the VO2 and ZnO layers, cross-sectional images of the orientation-controlled VO2 thin films were examined using a transmission electron microscope (TEM). As revealed by the TEM images, for the VO2 thin films deposited on a relatively thick ZnO buffer (? 70 nm), an interface layer was formed between the VO2 and ZnO layers. The interface layer was identified as V3O5 based on X-ray photoelectron spectra (XPS) and high resolution TEM images. For the VO2 thin films deposited on a 5-nm thick ZnO buffer, only a b-axis oriented VO2 layer was observed. The b-axis oriented VO2 layer displayed a columnar structure, and the layer thickness was occupied by one grain. However, TEM images of the thicker VO2 thin films (? 90 nm) deposited on 5-nm ZnO buffer revealed a VO2 (111) facet on the grain and amorphous residues of VO2. These results indicated that the grains of VO2 grew from the interface with the ZnO buffer, and the grain growth was slower than the speed of deposition. - Highlights: ? B-axis oriented VO2 thin films were prepared on glass on ZnO buffer layers. ? Transmission electron microscopy confirms the formation of an interface layer. ? X-ray photoelectron spectroscopy data reveal a V3O5 interface layer. ? VO2 (111) facet on grains and amorphous residues of VO2 were observed. ? The grain growth was slower than the rate of deposition

  8. Visible light driven photocatalysis and antibacterial activity of AgVO{sub 3} and Ag/AgVO{sub 3} nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Anamika [Department of Life Sciences, University of Mumbai, Santacruz (E), Mumbai 400 098 (India); Dutta, Dimple P., E-mail: dimpled@barc.gov.in [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Ballal, A. [Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Tyagi, A.K. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Fulekar, M.H. [School of Environment and Sustainable Development, Central University of Gujarat, Gandhinagar 382 030, Gujarat (India)

    2014-03-01

    Graphical abstract: - Highlights: • Ag/AgVO{sub 3} and pure AgVO{sub 3} nanowires synthesized by sonochemical process. • Characterization done using XRD, SEM, TEM, EDX and BET analysis. • Visible light degradation of RhB by Ag/AgVO{sub 3} within 45 min. • Antibacterial activity of Ag/AgVO{sub 3} demonstrated. - Abstract: Ag/AgVO{sub 3} nanowires and AgVO{sub 3} nanorods were synthesized in aqueous media via a facile sonochemical route. The as-synthesized products were characterized by X-ray diffraction, Brunauer–Emmett–Teller surface area analysis, scanning electron microscopy together with an energy dispersion X-ray spectrum analysis, transmission electron microscopy and UV–vis diffuse reflectance spectroscopy. The results revealed that inert atmosphere promotes the formation of Ag/AgVO{sub 3} nanowires. The photocatalytic studies revealed that the Ag/AgVO{sub 3} nanowires exhibited complete photocatalytic degradation of Rhodamine B within 45 min under visible light irradiation. The antibacterial activity of Ag/AgVO{sub 3} nanowires was tested against Escherechia coli and Bacillus subtilis. The minimum growth inhibitory concentration value was found to be 50 and 10 folds lower than for the antibiotic ciprofloxacin for E. coli and B. subtilis, respectively. The antibacterial properties of the β-AgVO{sub 3} nanorods prove that in case of the Ag dispersed Ag/AgVO{sub 3} nanowires, the enhanced antibacterial action is also due to contribution from the AgVO{sub 3} support.

  9. Synthesis, characterization and catalytic activity of two novel cis - dioxovanadium(V) complexes: [VO2(L)] and [VO2(HLox)

    International Nuclear Information System (INIS)

    Two novel complexes, [VO2(L)] (1) and [VO2(HLox)] (2), were synthesized and characterized by IV, UV-Vis and NMR spectroscopy, cyclic voltammetry, elemental analysis and X-ray diffraction. The synthesis of a new ligand, H2Lox, is also described. Complexes 1 and 2 were obtained by the reaction of [VO(acac)2] with the ligands HL and H2Lox, respectively. Alternatively, 2 was also obtained by the reaction of HL with [VO(acac)2] in the presence of hydroxylamine, and by the reaction of 1 with hydroxylamine. Crystallographic data show that complexes 1 and 2 have similar molecular structures, in which the cis-dioxovanadium(V) center is coordinated to L- or HLox-, respectively, in a distorted octahedral environment. The catalytic activity of these compounds towards cyclohexane oxidation was evaluated using H2O2 and t-BuOOH as oxidants. Both complexes presented > 70% selectivity for cyclohexylhydroperoxide formation. B3LYP/6.31G(d) calculations were used to confirm the geometry and to help assign the electronic spectra. (author)

  10. Conversión hidrotérmica suscritica de residuos orgánicos y biomasa. mecanismos de reacción

    OpenAIRE

    Castro Vega, Alejandro Amadeus; Rodríguez Varela, Luis Ignacio; Díaz Velásquez, José de Jesús

    2010-01-01

    La conversión hidrotérmica es un procedimiento que emula el proceso natural de conversión de la materia orgánica en un biocrudo con propiedades fisicoquímicas similares a las del petróleo. La transformación artificial de biomasa requiere conocer previamente las rutas de reacción y productos prevalentes. En la conversión de celulosa, el principal componente de la biomasa, se presenta despolimerización por hidrólisis y se obtienen oli- gosacaridos, los cuales presentan deshidratación y condens...

  11. An Analysis for Anonymity and Unlinkability for a VoIP Conversation

    OpenAIRE

    Zhang, Ge

    2010-01-01

    With the growth of its popularity, VoIP is increasingly popular nowadays. Similarly to other Internet applications, VoIP users may desire to be unlinkable with their participated VoIP session records for privacy issues. In this paper, we explore the Items of Interests (IOIs) from anonymisation aspects based on a simplified VoIP model and analyse the potential links between them. We address possible methods to break the links. Finally, we also discuss requirements for a VoIP anonymisation Serv...

  12. Current Status of VO Compliant Data Service in Japanese Virtual Observatory

    Science.gov (United States)

    Shirasaki, Y.; Komiya, Y.; Ohishi, M.; Mizumoto, Y.; Ishihara, Y.; Tsutsumi, J.; Hiyama, T.; Nakamoto, H.; Sakamoto, M.

    2012-09-01

    In these years, standards to build a Virtual Observatory (VO) data service have been established with the efforts in the International Virtual Observatory Alliance (IVOA). We applied these newly established standards (SSAP, TAP) to our VO service toolkit which was developed to implement earlier VO standards SIAP and (deprecated) SkyNode. The toolkit can be easily installed and provides a GUI interface to construct and manage VO service. In this paper, we describes the architecture of our toolkit and how it is used to start hosting VO service.

  13. Efecto de la depuracin en la biomasa del caracol Pomacea patula [Baker, 1922] usando el ndice de condicin

    Directory of Open Access Journals (Sweden)

    M. Garca-Ulloa

    2006-01-01

    Full Text Available La depuracin de organismos acuticos en cultivo es una prctica comn. El tiempo de exposicin de los animales al agua tratada es uno de los factores ms importantes para su eficiencia, pudiendo afectar su biomasa. Se evalu el efecto de la depuracin en adultos de Pomacea patula mediante la aplicacin del ndice de condicin (IC, bajo condiciones de laboratorio. Caracoles adultos obtenidos en cultivo se mantuvieron en peceras (Grupo 1 expuestos a un flujo de agua constante, tratada con radiacin ultravioleta y limpieza diaria y en condiciones normales de mantenimiento (Grupo 2, con 5 rplicas por grupo. Se obtuvo el peso hmedo y longitud total individualmente, al inicio y despus de una depuracin de 10 das. El valor promedio del coeficiente de correlacin (animales iniciales y de los Grupos 1 y 2 fue mayor a 0.90. El IC entre el valor inicial (771.81 40.41 y los Grupos 1 y 2 (763.527 25.24 y 765.465 38.59, respectivamente, no mostr diferencias significativas (P > 0.05 al final del experimento. Los resultados sugieren que el proceso de depuracin usado no afect la biomasa de adultos de P. patula. El IC se mostr como una herramienta prctica de evaluacin sin considerar la diferencia inicial de tallas de caracoles adultos

  14. Synthesis of novel photocatalytic RGO-InVO{sub 4} nanocomposites with visible light photoactivity

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Jianfeng; Li, Xianfu [Department of Materials Science, Fudan University, Shanghai, 200433 (China); Huang, Weishi; Li, Na [Center of Special Materials and Technology, Fudan University, Shanghai, 200433 (China); Ye, Mingxin, E-mail: mxye@fudan.edu.cn [Department of Materials Science, Fudan University, Shanghai, 200433 (China); Center of Special Materials and Technology, Fudan University, Shanghai, 200433 (China)

    2013-09-01

    Graphical abstract: A facile method for preparation of reduced graphene oxide (RGO) sheets supported indium vanadate (InVO{sub 4}) photocatalysts is reported. The visible light response and adsorption ability of RGO-InVO{sub 4} nanocomposites is greatly improved, which can effectively remove methyl orange and Cr (VI) from water. - Highlights: Supramolecular photocatalyst of RGO-InVO{sub 4} was achieved. Reduction of GO and preparation of RGO-InVO{sub 4} was simultaneous. The prepared RGO-InVO{sub 4} shows high photocatalytic activity and adsorption capacity under visible light. In situ growth of uniform InVO{sub 4} particles on RGO sheets is facile and efficient - Abstract: In this study, we report a facile method for preparation of reduced graphene oxide (RGO) sheets supported indium vanadate (InVO{sub 4}) photocatalysts. A wide range of characterization techniques, such as Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, Thermogravimetric analysis and Transmission electron microscopy were applied to characterize the obtained composites. The results indicated that the composites consist of uniformly dispersed InVO{sub 4} nanocrystals on RGO sheets. Visible light responses of RGO-InVO{sub 4} nanocomposites are greatly improved as compared with the bulk InVO{sub 4}. The as-prepared RGO-InVO{sub 4} nanocomposites can effectively remove methyl orange and Cr (VI) from water under visible light irradiation, which can be used as novel photocatalysts for environmental protection.

  15. Synthesis of novel photocatalytic RGO-InVO4 nanocomposites with visible light photoactivity

    International Nuclear Information System (INIS)

    Graphical abstract: A facile method for preparation of reduced graphene oxide (RGO) sheets supported indium vanadate (InVO4) photocatalysts is reported. The visible light response and adsorption ability of RGO-InVO4 nanocomposites is greatly improved, which can effectively remove methyl orange and Cr (VI) from water. - Highlights: Supramolecular photocatalyst of RGO-InVO4 was achieved. Reduction of GO and preparation of RGO-InVO4 was simultaneous. The prepared RGO-InVO4 shows high photocatalytic activity and adsorption capacity under visible light. In situ growth of uniform InVO4 particles on RGO sheets is facile and efficient - Abstract: In this study, we report a facile method for preparation of reduced graphene oxide (RGO) sheets supported indium vanadate (InVO4) photocatalysts. A wide range of characterization techniques, such as Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, Thermogravimetric analysis and Transmission electron microscopy were applied to characterize the obtained composites. The results indicated that the composites consist of uniformly dispersed InVO4 nanocrystals on RGO sheets. Visible light responses of RGO-InVO4 nanocomposites are greatly improved as compared with the bulk InVO4. The as-prepared RGO-InVO4 nanocomposites can effectively remove methyl orange and Cr (VI) from water under visible light irradiation, which can be used as novel photocatalysts for environmental protection

  16. Improving the Accuracy of Predicting Maximal Oxygen Consumption (VO2pk)

    Science.gov (United States)

    Downs, Meghan E.; Lee, Stuart M. C.; Ploutz-Snyder, Lori; Feiveson, Alan

    2016-01-01

    Maximal oxygen (VO2pk) is the maximum amount of oxygen that the body can use during intense exercise and is used for benchmarking endurance exercise capacity. The most accurate method to determineVO2pk requires continuous measurements of ventilation and gas exchange during an exercise test to maximal effort, which necessitates expensive equipment, a trained staff, and time to set-up the equipment. For astronauts, accurate VO2pk measures are important to assess mission critical task performance capabilities and to prescribe exercise intensities to optimize performance. Currently, astronauts perform submaximal exercise tests during flight to predict VO2pk; however, while submaximal VO2pk prediction equations provide reliable estimates of mean VO2pk for populations, they can be unacceptably inaccurate for a given individual. The error in current predictions and logistical limitations of measuring VO2pk, particularly during spaceflight, highlights the need for improved estimation methods.

  17. Terbium-Doped VO2 Thin Films: Reduced Phase Transition Temperature and Largely Enhanced Luminous Transmittance.

    Science.gov (United States)

    Wang, Ning; Duchamp, Martial; Dunin-Borkowski, Rafal E; Liu, Shiyu; Zeng, XianTing; Cao, Xun; Long, Yi

    2016-01-26

    Vanadium dioxide (VO2) is a well-known thermochromic material with large IR modulating ability, promising for energy-saving smart windows. The main drawbacks of VO2 are its high phase transition temperature (?c = 68 C), low luminous transmission (Tlum), and weak solar modulating ability (?Tsol). In this paper, the terbium cation (Tb(3+)) doping was first reported to reduce ?c and increase Tlum of VO2 thin films. Compared with pristine VO2, 2 at. % doping level gives both enhanced Tlum and ?Tsol from 45.8% to 54.0% and 7.7% to 8.3%, respectively. The Tlum increases with continuous Tb(3+) doping and reaches 79.4% at 6 at. % doping level, representing ?73.4% relative increment compared with pure VO2. This has surpassed the best reported doped VO2 thin films. The enhanced thermochromic properties is meaningful for smart window applications of VO2 materials. PMID:26729057

  18. 76 FR 59916 - Interconnected VoIP Service; Wireless E911 Location Accuracy Requirements; E911 Requirements for...

    Science.gov (United States)

    2011-09-28

    ...interconnected VoIP service providers to automatically...regulations to VoIP services that are not fully...limitations for use in next generation public safety applications...for nomadic VoIP services; and consider extending...providers of over-the-top VoIP...

  19. Bandwidth-Conserving Multicast VoIP Teleconference System

    Directory of Open Access Journals (Sweden)

    Teck-Kuen Chua

    2008-07-01

    Full Text Available Teleconferencing is an essential feature in any business telephone system. A teleconference allows associates to engage in a group discussion by conducting a virtual meeting while remaining at geographically dispersed locations. Teleconferencing increases productivity while reducing travel costs and saving travel time. In a VoIP telephone system, we face the significant challenge of providing a teleconference feature that can support a large-scale teleconference without using excessive bandwidth. This paper presents a new, bandwidth-efficient way of implementing a real-time VoIP teleconference system. This new method provides all of the features that existing teleconference systems provide, but this new approach consumes considerably less data bandwidth than existing systems require. The new system allows a network with a given capacity to accommodate almost double the number of conference participants that an existing system would allow.

  20. Gate-tunable gigantic lattice deformation in VO2

    International Nuclear Information System (INIS)

    We examined the impact of electric field on crystal lattice of vanadium dioxide (VO2) in a field-effect transistor geometry by in-situ synchrotron x-ray diffraction measurements. Whereas the c-axis lattice parameter of VO2 decreases through the thermally induced insulator-to-metal phase transition, the gate-induced metallization was found to result in a significant increase of the c-axis length by almost 1% from that of the thermally stabilized insulating state. We also found that this gate-induced gigantic lattice deformation occurs even at the thermally stabilized metallic state, enabling dynamic control of c-axis lattice parameter by more than 1% at room temperature

  1. Electrocaloric effect of metal-insulator transition in VO2

    International Nuclear Information System (INIS)

    The electrocaloric effect was observed in association with an electric-field induced metal-insulator transition in VO2 using a calorimetric measurement under an applied voltage. For a VO2 plate with a 0.4?mm thickness located in the center of a capacitor-like structure, the metal-insulator transition was manipulated by applying a few volts. The occurrence of a transition in such a thick sample with relatively low voltage indicates that a surface charge accumulation mechanism is effective. The isothermal entropy change reached 94?J kg?1 K?1, while the adiabatic temperature change was calculated as ?3.8?K under a voltage change of 03?V. The large entropy change is attributed to correlation of the complex freedom among spin, charge, and lattice

  2. CAN WE CONFIDENTLY STUDY VO2 KINETICS IN YOUNG PEOPLE?

    Directory of Open Access Journals (Sweden)

    Samantha G. Fawkner

    2007-09-01

    Full Text Available The study of VO2 kinetics offers the potential to non-invasively examine the cardiorespiratory and metabolic response to dynamic exercise and limitations to every day physical activity. Its non-invasive nature makes it hugely attractive for use with young people, both healthy and those with disease, and yet the literature, whilst growing with respect to adults, remains confined to a cluster of studies with these special populations. It is most likely that this is partly due to the methodological difficulties involved in studying VO2 kinetics in young people which are not present, or present to a lesser degree, with adults. This article reviews these methodological issues, and explains the main procedures that might be used to overcome them

  3. Synergy Between Archives, VO, and the Grid at ESAC

    Science.gov (United States)

    Arviset, C.; Alvarez, R.; Gabriel, C.; Osuna, P.; Ott, S.

    2011-07-01

    Over the years, in support to the Science Operations Centers at ESAC, we have set up two Grid infrastructures. These have been built: 1) to facilitate daily research for scientists at ESAC, 2) to provide high computing capabilities for project data processing pipelines (e.g., Herschel), 3) to support science operations activities (e.g., calibration monitoring). Furthermore, closer collaboration between the science archives, the Virtual Observatory (VO) and data processing activities has led to an other Grid use case: the Remote Interface to XMM-Newton SAS Analysis (RISA). This web service-based system allows users to launch SAS tasks transparently to the GRID, save results on http-based storage and visualize them through VO tools. This paper presents real and operational use cases of Grid usages in these contexts

  4. Epitaxial growth of VO{sub 2} by periodic annealing

    Energy Technology Data Exchange (ETDEWEB)

    Tashman, J. W.; Paik, H.; Merz, T. A. [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853-1501 (United States); Lee, J. H. [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853-1501 (United States); Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Moyer, J. A.; Schiffer, P. [Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Misra, R. [Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Mundy, J. A. [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 (United States); Spila, T. [Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Schubert, J. [Peter Grnberg Institute, PGI 9-IT, JARA-FIT, Research Centre Jlich, D-52425 Jlich (Germany); Muller, D. A. [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 (United States); Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853 (United States); Schlom, D. G., E-mail: schlom@cornell.edu [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853-1501 (United States); Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853 (United States)

    2014-02-10

    We report the growth of ultrathin VO{sub 2} films on rutile TiO{sub 2} (001) substrates via reactive molecular-beam epitaxy. The films were formed by the cyclical deposition of amorphous vanadium and its subsequent oxidation and transformation to VO{sub 2} via solid-phase epitaxy. Significant metal-insulator transitions were observed in films as thin as 2.3?nm, where a resistance change ?R/R of 25 was measured. Low angle annular dark field scanning transmission electron microscopy was used in conjunction with electron energy loss spectroscopy to study the film/substrate interface and revealed the vanadium to be tetravalent and the titanium interdiffusion to be limited to 1.6?nm.

  5. Epitaxial growth of VO2 by periodic annealing

    Science.gov (United States)

    Tashman, J. W.; Lee, J. H.; Paik, H.; Moyer, J. A.; Misra, R.; Mundy, J. A.; Spila, T.; Merz, T. A.; Schubert, J.; Muller, D. A.; Schiffer, P.; Schlom, D. G.

    2014-02-01

    We report the growth of ultrathin VO2 films on rutile TiO2 (001) substrates via reactive molecular-beam epitaxy. The films were formed by the cyclical deposition of amorphous vanadium and its subsequent oxidation and transformation to VO2 via solid-phase epitaxy. Significant metal-insulator transitions were observed in films as thin as 2.3 nm, where a resistance change ?R/R of 25 was measured. Low angle annular dark field scanning transmission electron microscopy was used in conjunction with electron energy loss spectroscopy to study the film/substrate interface and revealed the vanadium to be tetravalent and the titanium interdiffusion to be limited to 1.6 nm.

  6. Epitaxial growth of VO2 by periodic annealing

    International Nuclear Information System (INIS)

    We report the growth of ultrathin VO2 films on rutile TiO2 (001) substrates via reactive molecular-beam epitaxy. The films were formed by the cyclical deposition of amorphous vanadium and its subsequent oxidation and transformation to VO2 via solid-phase epitaxy. Significant metal-insulator transitions were observed in films as thin as 2.3?nm, where a resistance change ?R/R of 25 was measured. Low angle annular dark field scanning transmission electron microscopy was used in conjunction with electron energy loss spectroscopy to study the film/substrate interface and revealed the vanadium to be tetravalent and the titanium interdiffusion to be limited to 1.6?nm

  7. Evaluacin de desempeo de VoIP en redes MANET / Performance evaluation of VoIP in MANET

    Scientific Electronic Library Online (English)

    Patricia, Sing-Borrajo.

    2014-06-01

    Full Text Available Las redes MANET constituyen una opcin atractiva para soluciones de VoIP en escenarios que se caracterizan por la movilidad de los nodos y donde no exista una infraestructura previamente creada. Sin embargo, el soporte de servicios de voz enfrenta desafos ms rigurosos en redes MANET que los que ap [...] arecen en otras redes. La dinmica con que cambia la topologa causa que algunos parmetros importantes para medir la calidad como el retardo, la prdida de paquetes y la variacin del retardo se vean muy afectados. En este trabajo se mide mediante simulacin el impacto que tienen las mtricas: nmero de saltos, carga de trfico, densidad de los nodos y nmero de interrupciones de ruta en el desempeo de aplicaciones de VoIP en redes MANET. Con los resultados obtenidos se ha podido comprobar que las mtricas estudiadas tienen un comportamiento ms inestable en MANET que en otras redes tambin candidatas a soportar servicios mviles, sin embargo, existe mucha expectativa con la posibilidad de utilizar estas tecnologas (VoIP y MANET) para ofrecer telefona mvil de bajo costo gracias a la facilidad de despliegue y a la sencillez de su infraestructura. Abstract in english MANET networks are an attractive option for VoIP solutions in scenarios that are characterized by the mobility of nodes and where there is not a previously established infrastructure. However, the voice support faces more rigorous challenges in MANET networks than those of others networks. The dynam [...] ic with which topology changes affects important parameters to measure quality such as delay, packet loss and delay variation. In this work we measured the impact of metrics such as hop count, traffic load, node density and number of route breaks have over the performance of VoIP applications in MANET through simulation. Such simulations have allowed the comparison of the behavior of three important routing protocols. From the results reached, it has been shown that the studied metrics have a more unstable behavior in MANET than in other networks that are also candidates to carry mobile services. However, there is a lot of expectation with the possibility of using these technologies (VoIP and MANET) to provide lowcost mobile telephony due to the ease of deployment and simplicity of its infrastructure.

  8. Relao entre a variabilidade da frequncia cardaca e VO 2pico em mulheres ativas / Relationship between heart rate variability and VO 2peak in active women / Relacin entre la variabilidad de la frecuencia cardaca y VO 2pico en mujeres activas

    Scientific Electronic Library Online (English)

    Nayara Yamada, Tamburs; Ana Cristina Silva, Rebelo; Marcelo de Castro, Csar; Aparecida Maria, Catai; Anielle Cristhine de Medeiros, Takahashi; Carolina Pieroni, Andrade; Alberto, Porta; Ester da, Silva.

    2014-10-01

    Full Text Available OBJETIVO: Ava+liar a associao entre os ndices da variabilidade da frequncia cardaca (VFC) e a aptido cardiorrespiratria. MTODOS: Sessenta e duas mulheres (idade 22,1 3,3 anos) foram divididas em quatro grupos: treinamento aerbio (AER, n = 15), treinamento de fora (FOR, n = 13), tre [...] inamento combinado (aerbio e fora) (AER+FOR, n = 15) e controle (C, n = 19). O teste cardiopulmonar foi realizado para avaliar a aptido cardiorrespiratria a partir do consumo de oxignio pico (VO2pico). A FC foi coletada em repouso na postura supina. A VFC foi analisada a partir de mtodos lineares e no lineares. RESULTADOS: Os grupos AER e AER+FOR apresentaram maiores ndices da VFC (lineares e no lineares) indicadores da modulao vagal e menores ndices da VFC indicadores da modulao simptica, em relao ao grupo C. Os grupos AER e AER+FOR apresentaram maior complexidade e menor regularidade dos intervalos RR e maior VO2pico em relao aos grupos FOR e C. O VO2pico apresentou correlao com os ndices da VFC. CONCLUSO: Este estudo mostrou que o treinamento fsico aerbio e combinado contriburam significativamente para maior modulao autnoma da FC e aptido cardiorrespiratria. A modulao autnoma da FC, avaliada a partir de mtodos lineares e no lineares, est associada ao maior consumo de oxignio. Abstract in spanish OBJETIVO: Evaluar la asociacin entre los ndices de variabilidad de la frecuencia cardaca (VFC) y la aptitud cardiorrespiratoria. MTODOS: Sesenta y dos mujeres (edad 22,1 3,3 aos) fueron divididas en cuatro grupos: entrenamiento aerbico (AER, n = 15), entrenamiento de fuerza (FOR, n = 1 [...] 3), entrenamiento combinado (aerbico y fuerza) (AER+FOR, n = 15) y control (C, n = 19). El test cardiopulmonar fue realizado para evaluar la aptitud cardiorrespiratoria a partir del consumo de oxgeno pico (VO2pico). La FC fue colectada en reposo en la postura supina. La VFC fue analizada a partir de mtodos lineales y no lineales. RESULTADOS: Los grupos AER y AER+FOR presentaron mayores ndices de VFC (lineales y no lineales) indicadores de la modulacin vagal y menores ndices de VFC indicadores de la modulacin simptica, en relacin al grupo C. Los grupos AER y AER+FOR presentaron mayor complejidad y menor regularidad de los intervalos RR y mayor VO2pico en relacin a los grupos FOR y C. O VO2pico present correlacin con los ndices de VFC. CONCLUSIN: Este estudio mostr que el entrenamiento fsico aerbico y combinado contribuyeron significativamente para mayor modulacin autnoma de FC y aptitud cardiorrespiratoria. La modulacin autnoma de FC, evaluada a partir de mtodos lineales y no lineales, est asociada al mayor consumo de oxgeno. Abstract in english OBJECTIVE: To evaluate the associations between heart rate variability (HRV) with cardiorespiratory fitness. METHODS: Sixty-two women (aged 22.1 3.3) were divided into four groups: aerobic training (AER, n = 15), strength training (STR, n = 13), combined aerobic and strength training (AER+ST [...] R, n = 15) and controls (C, n = 19). Cardiopulmonary exercise testing was performed to measure cardiorespiratory fitness by assessing peak oxygen consumption (VO2peak). The HR was recorded at rest in the supine position. The HRV was analyzed by linear and nonlinear methods. RESULTS: The AER and AER+STR groups had higher vagal HRV (linear and nonlinear) indicators of vagal modulation and lower indices of HRV indicators of sympathetic modulation, compared to group C. The AER and AER+STR groups showed greater complexity and lower regularity of R-R intervals and higher peak compared to STR and C groups. The VO2peak was correlated with HRV indices. CONCLUSION: This study showed that aerobic and combined exercise significantly contributed to greater autonomic modulation of HR and cardiorespiratory fitness. The autonomic HR modulation, assessed by linear and nonlinear methods, was associated with a greater oxygen consumption.

  9. Structural characterization of PrVO3 epitaxial thin films

    OpenAIRE

    Copie, O.; H. Rotella; Boullay, P.; Morales, M.; Pautrat, A.; David, A.; Mercey, B.; Pravarthana, D.; Infante, I.C.; Janolin, P. -E.; Prellier, W.

    2014-01-01

    Rare earth perovskite oxides constitute a wide family of materials presenting functional proper- ties strongly coupled to their crystalline structure. Here, we report on the experimental results on epitaxial PrVO3 deposited on SrTiO3 single crystal substrates by pulsed laser deposition. By com- bining advanced structural characterization tools, we have observed that the PVO unrelaxed film structure grown on STO, is characterized by two kinds of oriented domains whose epitaxial relations are: ...

  10. Structural analysis of strained LaVO$_3$ thin films

    OpenAIRE

    H. Rotella; Copie, O.; Mouillard-Steciuk, G.; Ouerdane, H.; Boullay, P.; ROUSSEL, P; Morales, M.; David, A.; Pautrat, A.; Mercey, B.; L. Lutterotti; Chateigner, D.; Prellier, W.

    2014-01-01

    While structure refinement is routinely achieved for simple bulk materials, the accurate structural determination still poses challenges for thin films due on the one hand to the small amount of material deposited on the thicker substrate and, on the other hand, to the intricate epitaxial relationships that substantially complicate standard X-ray diffraction analysis. Using a combined approach, we analyze the crystal structure of epitaxial LaVO$_3$ thin films grown on (100)-oriented SrTiO$_3$...

  11. Magnetism in Ni2FeVO6-?

    International Nuclear Information System (INIS)

    The temperature dependence of magnetization M(T) of new polycrystalline ilmenite Ni2FeVO6-? shows remarkable singularities which can be interpreted as a result of coexistence of three magnetic phases in its magnetic structure. A fit of the dependences following four different models, each of which a combination of three functions of chosen type, to the M(T) experimental dependence has been made. ((orig.))

  12. Measurement and analysis of VoIP server performance

    OpenAIRE

    Wang, Yusong Carl

    2008-01-01

    Voice over IP (VoIP) and Instant Messaging (IM) are rapidly changing our daily communication landscape. SIP and IM protocols are two of the most widely deployed protocols for these applications. However, there are still many practical challenges toward implementing SIP and IM in commercial products, and their performances in real large-scale systems have yet to be understood and optimized. In this project, we applied two open source benchmark tools, J absimul and SIPp, to investigate the perf...

  13. Charging of SAML-based federated VoIP services

    OpenAIRE

    Lutz, D J; Lamp, D; Mandic, P; Hecht, F.; Stiller, B.

    2010-01-01

    Whilst SAML-based federations are most often used by academic and semi-commercial institutions that focus only on attribute-based authentication, we foresee a growing interest for service providers providing charged services. Since more and more academic and semi-commercial federation participants offer Voice-over-IP (VoIP) services, this type of service provides an entry point into identity federation based payment. Therefore, this paper describes an approach on how to h...

  14. Ferroelectricity from spin supercurrents in LiCuVO4

    OpenAIRE

    Mourigal, M.; Enderle, M.; Kremer, R. K.; Law, J. M.; Fk, B.

    2011-01-01

    We have studied the magnetic structure of the ferroelectric frustrated spin-1/2 chain material LiCuVO4 in applied electric and magnetic fields using polarized neutrons. A symmetry and mean-field analysis of the data rules out the presence of static Dzyaloshinskii-Moriya interaction, while exchange striction is shown to be negligible by our specific-heat measurements. The experimentally observed magnetoelectric coupling is in excellent agreement with the predictions of a pure...

  15. TeleInViVo: a collaborative volume visualization application.

    Science.gov (United States)

    Coleman, J; Savchenko, A; Goettsch, A; Wang, K; Bono, P; Littlefield, R; Macedonia, C

    1997-01-01

    Converging technologies in the areas of networks, volume visualization algorithms, and computer performance have made possible the development of a new tool for collaboration, which extends the reach of health professionals, and other consumers of volumetric data around the world. TeleInViVo(tm) is a three-dimensional (3D) collaborative volume visualization tool for medical applications. It extends the capabilities of InViVo(tm), a fast volume visualization tool developed at the Fraunhofer IGD, Darmstadt, Germany [1-3], with efficient and intuitive network collaboration features for remote consultation and new modes of interaction. The software runs on both UNIX and Windows NT platforms. TeleInViVo provides a high degree of interactivity for the medical professional when interacting with the patient data, facilitates explanation and communication between field personnel and medical experts located far from the field, and permits viewing of the data in a multitude of ways designed to support rapid and accurate diagnosis. Current efforts involve architectural enhancements to support multiuser, distributed telemedical scenarios. The application includes the following features: Volume and subvolume data transmission at user specified resolution, Synchronization cues, Integration of Immersion Probe(tm), a 6 degree-of-freedom input device, for ergonomic 3D data exploration, Tools for measuring distances, Tools for planning instrument path, Arbitrary cutting planes in real time, Interactive segmentation tools, Virtual video recorder and playback (cine loops), 3D stereo mode. TeleInViVo is an essential part of the MUSTPAC-1 portable 3D ultrasound system developed by Battelle Pacific Northwest Labs, Richland, WA. PMID:10168908

  16. Implementation of Cloud Computing into VoIP

    Directory of Open Access Journals (Sweden)

    Floriana GEREA

    2012-08-01

    Full Text Available This article defines Cloud Computing and highlights key concepts, the benefits of using virtualization, its weaknesses and ways of combining it with classical VoIP technologies applied to large scale businesses. The analysis takes into consideration management strategies and resources for better customer orientation and risk management all for sustaining the Service Level Agreement (SLA. An important issue in cloud computing can be security and for this reason there are several security solution presented.

  17. Caracterizacin del bagazo de caa como biomasa vegetal / Characterization of the cane bagasse like vegetable biomass

    Scientific Electronic Library Online (English)

    Enma M., Manals-Cutio; Margarita, Penedo-Medina; Dolores, Salas-Tort.

    2015-08-01

    Full Text Available Este trabajo tiene como finalidad evaluar propiedades fsicas y qumicas de diferentes clases de tamao de muestras de bagazo de caa, como parte del estudio de descomposicin trmica de las mismas. Para la realizacin del anlisis granulomtrico del bagazo de caa se estudiaron dos muestras; obteni [...] ndose una distribucin muy variada, desde un fino polvo hasta partculas irregulares de gran tamao, las mayores acumulaciones fueron obtenidas para partculas menores de 0,5 mm y hasta 1mm de dimetro. En este estudio se desarrollaron dos mtodos: el Mtodo Diferencial y el Mtodo Acumulativo, obtenindose dimetros promedio de las muestras aproximadamente iguales por ambos mtodos, de manera que el dimetro promedio del bagazo de caa en general es de 0,453 mm. Aplicando la metodologa experimental y en las instalaciones adecuadas se evaluaron las propiedades qumicas de la biomasa estudiada: carbono fijo, voltiles, cenizas, humedad. Luego se determin la influencia del tamao de las partculas en las propiedades del bagazo de caa obtenindose que para la humedad y el carbono fijo no existe una tendencia definida en estos parmetros. En el caso del contenido de voltiles existe una tendencia al aumento de este contenido con el aumento del dimetro de las partculas, ocurriendo lo contrario para el contenido de cenizas. Se obtuvo una diferencia estadsticamente significativa entre la media de cada uno de estos parmetros entre un nivel de Dpi y otro, excepto para el caso del carbono fijo. Abstract in english In this work were evaluated physical and chemical properties of different classes of size of samples of bagasse cane, like part of the study of thermal decomposition of the same ones. Two samples were studied; being obtained a very varied distribution, from a fine powder until irregular particles of [...] great size, the biggest accumulations were obtained for particles smaller than 0,5mm and up to 1mm of diameter. In this study two methods were developed: the Differential Method and the Accumulative Method, being obtained diameters average of the approximately same samples by both methods, so that the diameter average of the bagasse cane in general is of 0,453mm. Applying the experimental methodology and in the appropriate facilities the chemical properties of the studied biomass were evaluated: fixed, volatile, ashy carbon, humidity. Then the influence of the size of the particles was determined in the properties of the cane trash being obtained that for the humidity and the fixed carbon doesn't exist a tendency defined in these parameters. In the case of the content of volatile a tendency exists to the increase of this content with the increase of the diameter of the particles, happening the opposite for the content of ashy. A difference was obtained statistically significant among the stocking of each one of these parameters among a level of Dpi and other, except for the case of the fixed carbon.

  18. Accuracy of peak VO2 assessments in career firefighters

    Directory of Open Access Journals (Sweden)

    Hong OiSaeng

    2011-09-01

    Full Text Available Abstract Background Sudden cardiac death is the leading cause of on-duty death in United States firefighters. Accurately assessing cardiopulmonary capacity is critical to preventing, or reducing, cardiovascular events in this population. Methods A total of 83 male firefighters performed Wellness-Fitness Initiative (WFI maximal exercise treadmill tests and direct peak VO2 assessments to volitional fatigue. Of the 83, 63 completed WFI sub-maximal exercise treadmill tests for comparison to directly measured peak VO2 and historical estimations. Results Maximal heart rates were overestimated by the traditional 220-age equation by about 5 beats per minute (p 2 was overestimated by the WFI maximal exercise treadmill and the historical WFI sub-maximal estimation by ~ 1MET and ~ 2 METs, respectively (p 2 when compared to directly measured peak VO2. Conclusion Accurate assessment of cardiopulmonary capacity is critical in determining appropriate duty assignments, and identification of potential cardiovascular problems, for firefighters. Estimation of cardiopulmonary fitness improves using the revised 2008 WFI sub-maximal equation.

  19. Electronic transport in VO2Experimentally calibrated Boltzmann transport modeling

    Science.gov (United States)

    Kinaci, Alper; Kado, Motohisa; Rosenmann, Daniel; Ling, Chen; Zhu, Gaohua; Banerjee, Debasish; Chan, Maria K. Y.

    2015-12-01

    Materials that undergo metal-insulator transitions (MITs) are under intense study, because the transition is scientifically fascinating and technologically promising for various applications. Among these materials, VO2 has served as a prototype due to its favorable transition temperature. While the physical underpinnings of the transition have been heavily investigated experimentally and computationally, quantitative modeling of electronic transport in the two phases has yet to be undertaken. In this work, we establish a density-functional-theory (DFT)-based approach with Hubbard U correction (DFT + U) to model electronic transport properties in VO2 in the semiconducting and metallic regimes, focusing on band transport using the Boltzmann transport equations. We synthesized high quality VO2 films and measured the transport quantities across the transition, in order to calibrate the free parameters in the model. We find that the experimental calibration of the Hubbard correction term can efficiently and adequately model the metallic and semiconducting phases, allowing for further computational design of MIT materials for desirable transport properties.

  20. CyberSKA Radio Imaging Metadata and VO Compliance Engineering

    Science.gov (United States)

    Anderson, K. R.; Rosolowsky, E.; Dowler, P.

    2013-10-01

    The CyberSKA project has written a specification for the metadata encapsulation of radio astronomy data products pursuant to insertion into the VO-compliant Common Archive Observation Model (CAOM) database hosted by the Canadian Astronomy Data Centre (CADC). This specification accommodates radio FITS Image and UV Visibility data, as well as pure CASA Tables Imaging and Visibility Measurement Sets. To extract and engineer radio metadata, we have authored two software packages: metaData (v0.5.0) and mddb (v1.3). Together, these Python packages can convert all the above stated data format types into concise FITS-like header files, engineer the metadata to conform to the CAOM data model, and then insert these engineered data into the CADC database, which subsequently becomes published through the Canadian Virtual Observatory. The metaData and mddb packages have, for the first time, published ALMA imaging data on VO services. Our ongoing work aims to integrate visibility data from ALMA and the SKA into VO services and to enable user-submitted radio data to move seamlessly into the Virtual Observatory.

  1. Structural and morphology comparison between m-LaVO4 and LaVO3 compounds prepared by sol-gel acrylamide polymerization and solid state reaction

    International Nuclear Information System (INIS)

    We contrast the production of LaVO3 polycrystalline samples obtained by reduction of m-LaVO4 prepared by sol-gel acrylamide polymerization (SGAP) and solid state reaction (SSR). For SGAP the formation of m-LaVO4 occurs at 400 deg. C, for SSR at 1400 deg. C. For m-LaVO4-SGAP we observe a homogeneous morphology with needle-shaped grains of 50 nm average size. The SSR presents a broader size distribution in the micrometer range. Both m-LaVO4 samples were reduced into LaVO3 using a Zr rod at 850 deg. C in vacuum. LaVO3-SGAP presents a homogeneous grain distribution with an average size of 745 nm. LaVO3-SSR has an average size of 3.45 ?m. The stoichiometry of all compounds was confirmed by energy dispersive X-ray spectroscopy. X-ray powder diffraction and transmission electron microscopy give crystal structures in agreement with those reported in the literature.

  2. In situ high-pressure synchrotron X-ray diffraction study of the structural stability in NdVO{sub 4} and LaVO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Errandonea, D., E-mail: daniel.errandonea@uv.es [Departamento de Fsica Aplicada-ICMUV, MALTA Consolider Team, Universidad de Valencia, Edificio de Investigacin, C/Dr. Moliner 50, Burjassot, 46100 Valencia (Spain); Popescu, C. [CELLS-ALBA Synchrotron Light Facility, Cerdanyola, 08290 Barcelona (Spain); Achary, S.N.; Tyagi, A.K. [Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Bettinelli, M. [Luminiscent Materials Laboratory, DB and INSTM, Universit di Verona, Strada Le Grazie 15, I-37134 Verona (Italy)

    2014-02-01

    Highlights: NdVO{sub 4} and LaVO{sub 4} were studied under high pressure using synchrotron powder XRD. Both compounds exhibit first-order phase transitions. In NdVO{sub 4} the transition involves a symmetry breaking and in LaVO{sub 4} is isomorphic. The crystal structures of the high-pressure phases are assigned. Axial and bulk compressibilities are determined. - Abstract: Room-temperature angle-dispersive X-ray diffraction measurements on zircon-type NdVO{sub 4} and monazite-type LaVO{sub 4} were performed in a diamond-anvil cell up to 12 GPa. In NdVO{sub 4}, we found evidence for a non-reversible pressure-induced structural phase transition from zircon to a monazite-type structure at 6.5 GPa. Monazite-type LaVO{sub 4} also exhibits a phase transition but at 8.6 GPa. In this case the transition is reversible and isomorphic. In both compounds the pressure induced transitions involve a large volume collapse. Finally, the equations of state and axial compressibilities for the low-pressure phases are also determined.

  3. PRODUCCIN DE BIOMASA Y EXOPOLISACRIDOS DE Grifla frondosa BAJO CULTIVO SUMERGIDO UTILIZANDO FUENTES DE CARBONO NO CONVENCIONALES

    Directory of Open Access Journals (Sweden)

    Paula Zapata

    2007-06-01

    Full Text Available Grifla frondosa es un hongo Basidiomycete comestible y medicinal que produce polisacridos tipo glucanos (?-1,6 y ?-1,3 con actividad antitumoral e inmunomoduladora. Para el presente trabajo, el objetivo fue evaluar la incidencia de diferentes fuentes de carbono (FC en la produccin de biomasa y exopolisacri-dos (EPS, bajo condiciones de cultivo sumergido, utilizando un diseo estadstico factorial con dos factores: fuente de carbono (FC(1-7 y medio (MB y MS. La mxima produccin de biomasa micelial (21,10 0,82 g/l y la mxima produccin de EPS (6,53 0,14 g/l se logr utilizando el medio MB suplementado con FC4. Adems de lo anterior, se logr desarrollar un medio de cultivo que cumple con el objetivo de disminuir costos, de Col $18.455 a $656 por litro de medio, produciendo (14,14 0,82 g/l de biomasa y (5,16 0,14 g/l de EPS, utilizando el medio MS suplementando con FC4. Estos resultados abren nuevas alternativas y posibilidades en nuestro pas para el desarrollo de productos a partir de esta especie con costos que estn al alcance de la poblacin.Grifla frondosa is a Basidiomycete fungus edible and medicinal, it produces polysaccharides such a glucans (?-1,6 and ?-1,3 with anti-tumor and inmuno-stimulating activity. For this work, the aim was evaluate the incidence of different carbon sources (FC in biomass and exo-polymer (EPS production, under submerged culture conditions, by using a factorial statistical design with two factors: carbon source (FC(1-7 and medium (MB and MS. The maximal yield of mycelial biomass (21,10 0,82 g/l and the maximal yield in EPS (6,53 0,14 g/l was achieved by using the MB medium supplemented with FC4. Besides, it was possible to develop a medium that fulfills the objective of reducing costs from $18.455 to $656 Colombian pesos for each liter of medium used, which produces (14,14 0,82 g/l of biomass and (5,16 0,14 g/l of EPS, using the MS medium supplemented with FC4. This result opens new alternatives and possibilities in our country for developing products of this species with cost that can be reached by population.

  4. Dioxodichlorovanadate [VO2Cl2]-; preparation, vibrational spectrum, and crystal structure of [Ph3PMe][VO2Cl2

    International Nuclear Information System (INIS)

    The title compound was obtained from VO2Cl and [Ph3PMe]Cl in CH2Cl2 solution in form of orange crystals. Its crystal structure was determined with X-ray diffraction data and was refined to a residual index of R = 5.6% (2124 observed, independent reflexions). [Ph3PMe][VO2Cl2] crystallizes in the rhombic space group P212121 = D24 with four formula units in the unit cell. The low symmetry of the space group causes chirality of the cation. The complex anion is in good agreement with Csub(2v) symmetry; it is isoelectronic with CrO2Cl2. The vibrational spectrum (IR, Raman) was recorded and assigned. (author)

  5. Determinants of time limit at velocity corresponding to VO2max in physically active individuals

    Directory of Open Access Journals (Sweden)

    Jefferson da Silva Novaes

    2008-01-01

    Full Text Available The objective of the present study was to determine the relationship between time limit (Tlim at VO2Mx velocity (VVO2Mx and the variables VO2Mx, VVO2Mx, running economy (RE, ventilatory threshold (VT, strength test (9-10 maximum repetitions, velocity at maximal anaerobic running test (VMART, vertical jump test and body fat percentage. The sample was composed of 18 male volunteers, aged between 18 and 45 years old, non-athletes, but physically active. The study was carried out during fi ve visits, on non-consecutive days and at approximately the same time each day: visit 1 - signature of informed consent form, medical history, anthropometric assessment, aerobic power test and familiarization with Tlim test; visit 2 - RE test and Tlim test; visit 3 - familiarization with VMART test; visit 4 - familiarization with vertical jump and 9-10 maximum repetition tests and VMART test; visit 5 - vertical jump and 9-10 maximum repetition tests. Low (r = 0.220 to 0.359 and non-significant correlations (p = 0.281 to 0.935 were observed between Tlim and the selected variables, characterizing the low predictive value of Tlim for the sample studied. Thus, and because of the considerable inter-individual variability in Tlim, no variable was identified that was capable of satisfactorily predicting Tlim. Resumo O objetivo do presente estudo foi determinar a relao do tempo limite (Tlim na velocidade do VO2Mx (VVO2Mx com as variveis VO2Mx, VVO2Mx, economia de corrida (EC, limiar ventilatrio (LV, fora isotnica (determinada pelo teste de 9-10 RM, velocidade no teste mximo de corrida anaerbica (VMART, impulso vertical e percentual de gordura (%G . A amostra foi composta por 18 voluntrios do sexo masculino, com idade entre 18 e 45 anos, no atletas, regularmente ativos. O estudo foi realizado em cinco visitas, em dias no consecutivos e aproximadamente no mesmo horrio, compostas de: visita 1 - assinatura do termo de consentimento, anamnese, avaliao antropomtrica, teste de potncia aerbia e familiarizao ao teste de Tlim; visita 2 - teste de EC e teste de Tlim; visita 3 - familiarizao ao teste de VMART; visita 4 - familiarizao aos testes de impulso vertical e 9-10 RM e teste de VMART; visita 5 - testes de impulso vertical e 9-10 RM. Foram observadas correlaes baixas (r = 0,220 a - 0,359 e no significativas (p = 0,281 a 0,935 entre Tlim e as diversas variveis selecionadas, o que caracteriza uma baixa qualidade preditiva para o TLim na amostra estudada. Neste sentido e tendo em vista a considervel variabilidade inter-indivduos do TLim, no foi encontrada uma varivel que pudesse prediz-lo satisfatoriamente.

  6. Liquidus surface of NaNO3-Na2W2O7-WO3 system

    International Nuclear Information System (INIS)

    State diagrams of the system sodium metavanadate-tungsten (6) oxide, liquidus surface of the system sodium metavanadate-sodium ditungstate-tungsten (6) oxide were studied. In the first system two new phases 3NaVO3WO3 and NaNO32WO3 are formed. Diagram of primary crystallization surface of the second system is plotted. Compositions and melting points of ternary nonvariant points are determined

  7. Empleo de la relación residuo producto para la estimación de biomasa cañera potencial. Caso de estudio

    Directory of Open Access Journals (Sweden)

    Lizet Rodríguez-Machín

    2014-01-01

    Full Text Available El panorama energético de la biomasa va tomando un mayor auge ante el vaticinado agotamiento de los combustibles fósiles, el impacto ambiental que representa y la seguridad energética asociada. El presente trabajo se desarrolla en la Unidad Empresarial de Base (UEB Héctor Rodríguez. Esta unidad emplea el bagazo obtenido en el proceso industrial de producción de azúcar para la generación de calor y de electricidad sin estimar adecuadamente su potencial. El propósito de esta investigación es aplicar las ecuaciones matemáticas para la estimación de la biomasa herbácea potencial al caso de la biomasa cañera (bagazo y conocer su disponibilidad con fines energéticos. Se aplicó el método de evaluación con relación residuo producto (RRP, el valor calculado está dentro del rango de los reportados en la literatura, pero fue preciso emplear el RRP calculado para el país por ser este más representativo que el calculado para la UEB. Se estimó que la biomasa potencial en central azucarero entre 2007 y 2012 fue de 98 856 t de bagazo. El potencial bruto máximo fue de 3 222 MW-h/día, lo cual permite establecer el límite superior a alcanzar en cuanto a potencial de biomasa se refiere en el proceso industrial pero no tiene en cuenta la totalidad de la caña producida en el proceso agrícola.

  8. Determinacin de las reservas de carbono en la biomasa area de sistemas agroforestales de theobroma cacao l. en el departamento de San Martn, Per

    Directory of Open Access Journals (Sweden)

    Juanita Y. Concha

    2007-01-01

    Full Text Available En este estudio se evalu la biomasa area en seis diferentes sistemas agroforestales de cacao (Theobroma cacao L. asociado con especies forestales maderables y frutales; con el propsito de conocer el potencial de captura de carbono por cada sistema. El estudio se realiz en dos diferentes sitios ubicados en la regin San Martn (provincias de San Martn y Mariscal Cceres. Los sistemas agroforestales estimados presentaron edades de 5, 12 y 20 aos. En cada sistema se establecieron aleatoriamente cinco cuadrantes de 100 m2 cada uno, evalundose la biomasa vegetal total existente. Para evaluar la ecuacin alomtrica del cacao se muestrearon 7 plantas cuyas edades variaron de 01 hasta 22 aos. Loas resultados en captura de carbono en cada sistema agroforestal varan desde 26.2 t C ha-1para el sistema de Pachiza de 5 aos hasta 45.07 t C ha-1del sistema agroforestal de Pachiza de 12 aos; As mismo, la captura de carbono en biomasa arbrea de los rboles vivos, oscil desde 12.09 t ha-1 hasta 35.5 t ha-1, seguido por la biomasa de hojarasca que presentaron valores desde 4 t ha-1 hasta 9.97 t ha-1; mientras la biomasa de rboles muertos en pie y cados muertos presentaron valores muy variables y bajos. Los sistemas agroforestales de 12 y 20 aos representan el 66.7% de los sistemas que presentan reservas de carbono por encima de los 40 t C ha-1; mientras que los sistemas de 5 aos se encuentran con reservas de carbono por debajo de los 30 t C ha-1. Los sistemas agroforestales de 5 aos ubicados en Juanjui y Pachiza presentaron el mayor flujo de carbono anual, generando el mayor beneficio econmico con crditos por CO2 equivalente

  9. CO Oxidation Promoted by the Gold Dimer in Au2 VO3 (-) and Au2 VO4 (-) Clusters.

    Science.gov (United States)

    Wang, Li-Na; Li, Zi-Yu; Liu, Qing-Yu; Meng, Jing-Heng; He, Sheng-Gui; Ma, Tong-Mei

    2015-09-28

    Investigations on the reactivity of atomic clusters have led to the identification of the elementary steps involved in catalytic CO oxidation, a prototypical reaction in heterogeneous catalysis. The atomic oxygen species O(.-) and O(2-) bonded to early-transition-metal oxide clusters have been shown to oxidize CO. This study reports that when an Au2 dimer is incorporated within the cluster, the molecular oxygen species O2 (2-) bonded to vanadium can be activated to oxidize CO under thermal collision conditions. The gold dimer was doped into Au2 VO4 (-) cluster ions which then reacted with CO in an ion-trap reactor to produce Au2 VO3 (-) and then Au2 VO2 (-) . The dynamic nature of gold in terms of electron storage and release promotes CO oxidation and O-O bond reduction. The oxidation of CO by atomic clusters in this study parallels similar behavior reported for the oxidation of CO by supported gold catalysts. PMID:26267648

  10. Gallinaza: Un residual avícola como fuente alternativa de nutrientes para producción de biomasa microalgal

    Directory of Open Access Journals (Sweden)

    Rosales Loaiza Nestor Luis

    2007-07-01

    Full Text Available La gallinaza puede ser usada como una fuente alternativa de nutrientes para el cultivo de microalgas, proveyendo de biomasa microalgal utilizable como producto final. El objetivo de este trabajo fue evaluar el efecto de la fracción soluble de gallinaza (FSG a tres diferentes concentraciones (6, 18 y 36% sobre el crecimiento, la producción de pigmentos y proteínas de la microalga marina Chroomonas sp. y de la microalga de agua dulce Chlorella sorokiniana. La FSG no biodegradada mostró un efecto letal sobre el crecimiento de ambas microalgas. La FSG tratada aeróbicamente mejoró el crecimiento de Chroomonas sp. a 18% con 131,37 ±13,66 x106 cel mL-1, y a 36% para C. sorokiniana de 228,64 ±4,90 x106 cel mL-1 (p

  11. BIOMASA, DENSIDAD Y COMPOSICION ZOOPLANCTONICA DE LA BAHIA DE MOCHIMA, VENEZUELA / Zooplankton biomass, density and composition in Mochima Bay, Venezuela

    Scientific Electronic Library Online (English)

    Brightdoom, Mrquez-Rojas; Baumar, Marn; J.R, Daz-Ramos; Luis, Troccoli.

    2008-06-01

    Full Text Available La biomasa, densidad y composicin del zooplancton de la baha de Mochima fueron estudiadas durante 1998. Las muestras fueron recolectadas mensualmente en la entrada de la baha (estacin A) y en la parte interna (estacin B) entre enero y diciembre de 1998. En cada estacin se realizaron calados ob [...] licuos con una malla estndar de 300 micras y 0,25 m de dimetro de boca a 0-5 y 10-15 m y a una velocidad de dos nudos durante 10 min. El ndice de surgencia se calcul a partir de los datos de vientos. Se midi salinidad, temperatura del agua, concentracin de oxgeno disuelto, concentracin de clorofila a, biomasa y densidad del zooplancton; adems se identificaron los organismos, en lo posible hasta especie. Los perfiles de temperatura mostraron un mayor tiempo de permanencia de aguas clidas superficiales en la estacin ms interna. Los valores ms altos de densidad zooplanctnica (4066 ind/m) se registraron en el perodo febrero - mayo y luego los valores fueron relativamente bajos ( Abstract in english Zooplankton biomass, density and composition were studied in Mochima Bay during 1998. Samples were collected at monthly intervals at stations located at the mouth and the interior of the bay from January to December 1998. At each station, samples were collected in the intervals 0-5 and 10-15 m with [...] a Standard net of 300 m and 0,25 m at a speed of two knots during ten minutes. Wind data was used to calculate the upwelling index. Salinity, water temperature, concentration of dissolved oxygen and chlorophyll a (chl a), and zooplankton biomass and density were measured at the two stations. Also, the organisms were identified to group level. Temperature profiles showed a greater residence time for warm waters in the internal part of the bay than in the external one. Higher zooplankton density values (4066 ind/m) were found during the period February - May. Values were relatively low (

  12. Continuous tuning of W-doped VO2 optical properties for terahertz analog applications

    International Nuclear Information System (INIS)

    Vanadium dioxide (VO2), with its characteristic metal-insulator phase transition, is a prospective active candidate to realize tunable optical devices operating at terahertz (THz) frequencies. However, the abrupt phase transition restricts its practical use in analog-like continuous applications. Incorporation of tungsten is a feasible approach to alter the phase transition properties of thin VO2 films. We show that amplitude THz modulation depth of ?65%, characteristic phase transition temperature of ?40?C, and tuning range larger than 35?C can be achieved with W-doped VO2 films grown on sapphire substrates. W-doped VO2 films can also be used to suppress Fabry-Perot resonances at THz frequencies but at temperatures much lower than that observed for undoped VO2 films. The gradual phase transition temperature window allows for precise control of the W-doped VO2 optical properties for future analog based THz devices

  13. Prior Knowledge of Trial Number Influences the Incidence of Plateau at VO2max

    OpenAIRE

    Gordon, Dan; Caddy, Oliver; Merzbach, Viviane; Gernigon, Marie; Baker, James; Scruton, Adrian; Keiller, Don; Barnes, Richard

    2015-01-01

    The purpose of this study was to assess the VO2max plateau response at VO2max during a series of pre-determined trials. METHODS: Ten male well-trained athletes (age, 23.0 3.2; height, 183.3 5.5 cm; mass 77.5 11.1 Kg; VO2max 66.5 5.0 ml.kg-1,min-1), but who were VO2max testing nave and with prior-knowledge of trial number completed four incremental tests to volitional exhaustion, separated by ~72-h for the determination of VO2max and gas exchange threshold. Throughout all trials VO2ma...

  14. Carbon quantum dots coated BiVO{sub 4} inverse opals for enhanced photoelectrochemical hydrogen generation

    Energy Technology Data Exchange (ETDEWEB)

    Nan, Feng; Shen, Mingrong; Fang, Liang, E-mail: zhkang@suda.edu.cn, E-mail: lfang@suda.edu.cn [College of Physics, Optoelectronics and Energy and Jiangsu Key Laboratory of Thin Films, Soochow University, Suzhou 215006 (China); Kang, Zhenhui, E-mail: zhkang@suda.edu.cn, E-mail: lfang@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Wang, Junling [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2015-04-13

    Carbon quantum dots (CQDs) coated BiVO{sub 4} inverse opal (io-BiVO{sub 4}) structure that shows dramatic improvement of photoelectrochemical hydrogen generation has been fabricated using electrodeposition with a template. The io-BiVO{sub 4} maximizes photon trapping through slow light effect, while maintaining adequate surface area for effective redox reactions. CQDs are then incorporated to the io-BiVO{sub 4} to further improve the photoconversion efficiency. Due to the strong visible light absorption property of CQDs and enhanced separation of the photoexcited electrons, the CQDs coated io-BiVO{sub 4} exhibit a maximum photo-to-hydrogen conversion efficiency of 0.35%, which is 6 times higher than that of the pure BiVO{sub 4} thin films. This work is a good example of designing composite photoelectrode by combining quantum dots and photonic crystal.

  15. Building a VO-compliant Radio Astronomical DAta Model for Single-dish radio telescopes (RADAMS)

    CERN Document Server

    Santander-Vela, J D; Leon, S; Espigares, V; Ruiz, J E; Verdes-Montenegro, L; Solano, E

    2012-01-01

    The Virtual Observatory (VO) is becoming the de-facto standard for astronomical data publication. However, the number of radio astronomical archives is still low in general, and even lower is the number of radio astronomical data available through the VO. In order to facilitate the building of new radio astronomical archives, easing at the same time their interoperability with VO framework, we have developed a VO-compliant data model which provides interoperable data semantics for radio data. That model, which we call the Radio Astronomical DAta Model for Single-dish (RADAMS) has been built using standards of (and recommendations from) the International Virtual Observatory Alliance (IVOA). This article describes the RADAMS and its components, including archived entities and their relationships to VO metadata. We show that by using IVOA principles and concepts, the effort needed for both the development of the archives and their VO compatibility has been lowered, and the joint development of two radio astronom...

  16. Biomasa de Eucalyptus nitens de 4-7 aos de edad en un rodal de la X Regin, Chile Biomass of 4-7 year-old Eucalyptus nitens in a stand in the X Region, Chile

    OpenAIRE

    Edith Geldres; Vctor Gerding; JUAN E. SCHLATTER

    2006-01-01

    Se estim la biomasa total de una plantacin de Eucalyptus nitens en una secuencia de edad de 4 a 7 aos, con fertilizacin (X Regin, 4101S-7327O), en un suelo rojo arcilloso de la serie Crucero. La biomasa del bosque en las edades de 4, 5 y 7 aos fue estimada a partir del respectivo rbol de dimetro medio cuadrtico; a los 6 aos fue interpolada. Se obtuvieron componentes de la copa, tronco y races; adems se midi mantillo y hojarasca. La biomasa total del rodal alcanz a 92 t ha-1 ...

  17. Insights into Stabilization of the 99TcVO Core for Synthesis of 99TcVO Compounds

    Energy Technology Data Exchange (ETDEWEB)

    McGregor, Donna; Burton-Pye, Benjamin P.; Lukens, Wayne W.; Howell, Robertha C.; Francesconi, Lynn C.

    2014-01-01

    Synthesis of technetium-99 (99Tc; t1/2: 2.1 105 years, max: 253 keV) materials is of importance in studies of the nuclear fuel cycle where Tc is a major fission product (6percent thermal yield from 235U and 239Pu), in understanding radioactive tank waste composition, and in identifying 99mTc compounds for nuclear medicine imaging. One of the most useful synthetic starting materials, (NBu4)TcOCl4, is susceptible to disproportionation in water to form TcO4 and TcIV species, especially TcO2 2H2O. This unwanted reaction is especially problematic when working with ligands bearing hard donor atoms, such as oxygen, where the stability with the soft TcV=O3+ core may be low. Polyoxometalates (POMs) are such ligands. They possess defect sites with four hard oxygen atoms and show low (ca. 108) stability constants with transition metals. Tc complexes of POMs are molecular-level models for Tc metal oxide solid-state materials and can provide information on coordination and redox environments of metal oxides that stabilize low-valent Tc. In order to synthesize pure Tc POM complexes [TcVO(1-P2W17O61)]7 (TcVO-1) and [TcVO(2-P2W17O61)]7 (TcVO-2) from (NBu4)TcOCl4, we have identified strategies that minimize formation of TcIV species and optimize the formation of pure TcV species. The parameters that we consider are the amount of ethylene glycol, which is employed as a transfer ligand to prevent hydrolysis of (NBu4)TcOCl4, and the precipitating agent. The TcIV species that contaminates the non-optimized syntheses is likely a TcIV -oxido-bridged dimer [TcIV-(-O)2-TcIV]. We also employ a novel procedure where the 2 ligand is photoactivated and reduced (in the presence of a sacrificial electron donor) to subsequently reduce TcVIIO4 to an isolatable TcVO-2 product that is remarkably free of TcIV.

  18. Transmission increase upon switching of VO2 thin films on microstructured surfaces

    OpenAIRE

    KARAKURT, ?smail; Boneberg, Johannes; Leiderer, Paul; Lopez, R.; Halabica, A.; Richard F. Haglund

    2007-01-01

    The authors compare transmission measurements of near-infrared light through VO2 thin films on smooth substrates and on ordered arrays of silica microspheres. When the samples are heated above the critical temperature for the semiconductor-metallic phase transition, smooth thin films show reduced transmission independent of thickness; however, the VO2 film deposited on the microspheres may show either reduced or enhanced transmission, depending on VO2 film thickness. They show that this at a ...

  19. Transmission increase upon switching VO2 thin films on microstructured surfaces

    OpenAIRE

    Karakurt, Ismail; Boneberg, Johannes; Leiderer, Paul; Lopez, Rene; Halabica, Andrej; Haglund, Richard

    2007-01-01

    The authors compare transmission measurements of near-infrared light through VO2 thin films on smooth substrates and on ordered arrays of silica microspheres. When the samples are heated above the critical temperature for the semiconductor-metallic phase transition, smooth thin films show reduced transmission independent of thickness: however, the VO2 film deposited on the microspheres may show either reduced or enhanced transmission, depending on VO2 film thickness. They show that this at a ...

  20. Instantaneous Band Gap Collapse in Photoexcited Monoclinic VO2 due to Photocarrier Doping

    OpenAIRE

    Wegkamp, D.; Herzog, M.; Xian, L; Gatti, M.; Cudazzo, P.; McGahan, C.; Marvel, R.; Haglund, R.; Rubio, A.; Wolf, M.; Sthler, J.

    2014-01-01

    Using femtosecond time-resolved photoelectron spectroscopy we demonstrate that photoexcitation transforms monoclinic VO2 quasi-instantaneously into a metal. Thereby, we exclude an 80 fs structural bottleneck for the photoinduced electronic phase transition of VO2. First-principles many-body perturbation theory calculations reveal a high sensitivity of the VO2 band gap to variations of the dynamically screened Coulomb interaction, supporting a fully electronically driven isostructural insulato...

  1. A study of mobile VoIP performance in wireless broadband networks

    OpenAIRE

    Arjona, Andres

    2009-01-01

    Voice service is to date still the killer mobile service and the main source for operator revenue for years to come. Additionally, voice service will evolve from circuit switched technologies towards packet based Voice over IP (VoIP). However, using VoIP over wireless networks different from 3GPP cellular technologies makes it also a disruptive technology in the traditional telecommunication sector. The focus of this dissertation is on determining mobile VoIP performance in different wir...

  2. VoIP Server HW/SW Codesign for Multicore Computing

    OpenAIRE

    Iqbal, Arshad

    2012-01-01

    Modern technologies are growing and Voice over Internet Protocol (VoIP) technology is able to function in heterogeneous networks. VoIP gained wide popularity because it offers cheap calling rates compared to traditional telephone system and the number of VoIP subscribers has increased significantly in recent years. End users need reliable and acceptable call quality in real time communication with best Quality of Service (QoS). Server complexity is increasing to handle all client requests sim...

  3. Peer-to-Peer VoIP Communications Using Anonymisation Overlay Networks

    OpenAIRE

    Zhang, Ge; Fischer-Hbner, Simone

    2010-01-01

    Nowadays, Voice over Internet Protocol (VoIP) which enables voice conversation remotely over packet switched networks gains much attentions for its low costs and flexible services. However, VoIP calling anonymity, particularly to withhold "who called whom", is difficult to achieve since VoIP infrastructures are usually deployed in an open networking environment (e.g., the Internet). Our work studies an anonymisation overlay network (AON) based solution to prevent surveillance from external at...

  4. Impact of VoIP and QoS on Open and Distance Learning

    Science.gov (United States)

    Saxena, P. C.; Jasola, Sanjay; Sharma, Ramesh C.

    2006-01-01

    Voice over Internet Protocol (VoIP) is becoming a reality in many organizations. The potential for mobility in voice over wi-fi networks will derive demand for the technology. Wireless VoIP is poised to rival VoIP as an alternative telephony tool. Internet has been used to transport data in the form of packet. In the past, Internet did not support

  5. VoIP Technology: Investigation of QoS and Security Issues

    OpenAIRE

    Amor Lazzez

    2014-01-01

    Voice over IP (VoIP) is the technology allowing voice traffic transmission as data packets over a private or a public IP network. VoIP allows significant benefits for customers and communication services providers. The main are cost savings, rich media service, phone and service portability and mobility, and the integration with other applications. Nevertheless, the deployment of the VoIP technology encounters many challenges such as architecture complexity, interoperability problems, QoS co...

  6. Gas-phase reactivity of metavanadate [VO3]- towards methanol and ethanol: experiment and theory.

    Science.gov (United States)

    Waters, Tom; Wedd, Anthony G; O'Hair, Richard A J

    2007-01-01

    The gas-phase reactivity of the metavanadate anion [VO3]- towards methanol and ethanol was examined by a combination of ion-molecule reaction and isotope labelling experiments in a quadrupole ion-trap mass spectrometer. The experimental data were interpreted with the aid of density functional theory calculations. [VO3]- dehydrated methanol to eliminate water and form [VO2(eta2-OCH2)]-, which features an [eta2-C,O-OCH2]2- ligand formed by formal removal of two protons from methanol and which is isoelectronic with peroxide. [VO3]- reacted with ethanol in an analogous manner to form [VO2(eta2-OCHCH3)]-, as well as by loss of ethene to form [VO2(OH)2]-. The calculations predicted that important intermediates in these reactions were the hydroxo alkoxo anions [VO2(OH)(OCH2R)]- (R: H, CH3). These were predicted to undergo intramolecular hydrogen-atom transfer to form [VO(OH)2(eta1-OCHR)]- followed by eta1-O-->eta2-C,O rearrangements to form [VO(OH)2(eta2-OCHR)]-. The latter reacted further to eliminate water and generate the product [VO2(eta2-OCHR)]-. This major product observed for [VO3]- is markedly different from that observed previously for [NbO3]- containing the heavier Group 5 congener niobium. In that case, the major product of the reaction was an ion of stoichiometry [Nb, O3, H2]- arising from the formal dehydrogenation of methanol to formaldehyde. The origin of this difference was examined theoretically and attributed to the intermediate alkoxo anion [NbO2(OH)(OCH3)]- preferring hydride transfer to form [HNbO2(OH)]- with loss of formaldehyde. This contrasts with the hydrogen-atom-transfer pathway observed for [VO2(OH)(OCH3)]-. PMID:17661322

  7. Validity of 20-MST for predicting VO2max of adult Singaporean athletes.

    OpenAIRE

    Sproule, J; Kunalan, C; M. Mcneill; Wright, H

    1993-01-01

    This investigation compared the results of direct and indirect measurements of maximum oxygen uptake (VO2max) of an Asian population. Twenty subjects (16 male, 4 female), all of whom were physical education students, were assessed directly using laboratory treadmill running to determine VO2max. The indirect estimation of VO2max was obtained using a modified form of the Leger and Lambert 20-m multistage shuttle run test (20-MST). Heart rates were recorded throughout both tests. Pearson product...

  8. A regression equation for the estimation of VO2max in Nepalese male adults

    OpenAIRE

    Pinaki Chatterjee; Alok K. Banerjee; Paulomi Das; Parimal Debnath

    2010-01-01

    The purpose of the study was to validate the applicability of 20-meter multi stage shuttle run test in Nepalese male College students. 40 Nepalese students were recruited for the study. Direct estimation of cardiorespiratory endurance (VO2max) comprised treadmill exercise followed by expired gas analysis by scholander micro-gas analyzer whereas VO2max was indirectly predicted by the 20-meter multistage shuttle run test. The difference between the mean (SD) VO2max values of direct measurement ...

  9. A Study of VO2 Max and Body Fat Percentage in Female Athletes

    OpenAIRE

    Shete, Anjali N.; Bute, Smita S; P. R. Deshmukh

    2014-01-01

    Introduction: Aerobic capacity of athletes is an important element of success in sports achievements. It is generally considered the best indicator of cardio respiratory endurance and athletic fitness. Body fat percentage affects VO2 max and thus the cardiovascular status of the athletes. The present study was undertaken to assess the VO2 max and body fat percentage in athletes. The secondary objective of the study was to study the relationship between VO2 max and body fat percentage.

  10. Efeito de diferentes misturas de substratos orgnicos na biomassa e no leo essencial de Thymus zygis / Effect of different mixtures of organic substrates on the biomass and essential oil of Thymus zygis

    Scientific Electronic Library Online (English)

    Nelson, Loureno; Susana A., Dandlen; Maria G., Miguel; Ana, Figueiredo; Jos, Barroso; Luis, Pedro; Lusa, Coelho; Mrio, Reis; Pedro J., Correia.

    2011-07-01

    Full Text Available Neste ensaio avaliou-se o efeito de diferentes misturas de substrato comercial e vermicomposto na produo de biomassa, composio qumica e rendimento dos leos essenciais de Thymus zygis. Utilizaram-se 5 substratos resultantes da mistura de um vermicomposto (V) com um substrato orgnico comercial [...] (O), em cinco propores diferentes (v/v): V100 (100%V); VO75-25 (75%V+25%O); VO50 -50 (50%V+50%O); VO 25-75 (25%V + 75%O) e O100 (100%O). A incluso do vermicomposto no substrato no melhorou a produo de biomassa. Na modalidade O100 produziu-se mais biomassa, tendo sido na modalidade VO25-75 onde se obteve o valor mais baixo. Na modalidade V100 todas as plantas secaram tendo-se ainda apresentado nesta modalidade o valor mais elevado de pH e de densidade real e inversamente o menor valor de espao poroso total. Os monoterpenos oxigenados predominaram nos leos extrados das plantas nas modalidades O100 e VO25-75, contrariamente ao que se verificou para os monoterpenos no oxigenados tendo estes predominado nas modalidades VO75-25 e VO50-50. A concentrao de timol foi elevada nas misturas testadas, em particular na modalidade VO25-75. Abstract in english In this trial we evaluated the effect of different mixtures of organic growing media substratum and vermicompost and their physical properties on biomass, chemical composition and yield of essential oils of Thymus zygis. Five treatments were established based on two types of organic materials (O, co [...] mmercial growing media, and V, vermicompost). The following proportions were studied (v/v): V100 (100%V); VO75-25 (75%V+25%O); VO50-50 (50%V+50%O); VO 25-75 (25%V+75%O) and O100 (100%O). The inclusion of vermicompost did not improve biomass production. The treatment O100 produced more biomass and the lowest was obtained in VO25-75. On V100 treatment all plants were dead and also have showed the highest pH and particle density and conversely presented the lowest value of total pore space. Oxygenated monoterpenes predominated in the oils extracted from plants in O100 and VO25-75, contrary to what was found for non-oxygenated monoterpenes having these prevailed in VO75-25 and VO50-50. The concentration of thymol was high in the mixtures tested, particularly in VO25-75.

  11. Ecuaciones de biomasa area para Quercus laurina y Q. crassifolia en Oaxaca / Aerial biomass equations for Quercus laurina and Q. crassifolia in Oaxaca

    Scientific Electronic Library Online (English)

    Faustino, Ruiz-Aquino; Juan Ignacio, Valdez-Hernndez; Filemn, Manzano-Mndez; Gerardo, Rodrguez-Ortiz; Anglica, Romero-Manzanares; Martha Elena, Fuentes-Lpez.

    2014-08-01

    Full Text Available La estimacin de la biomasa arbrea es un medio para determinar los montos existentes de carbono orgnico en cada uno de los componentes del rbol. Los estudios sobre biomasa area para especies del gnero Quercus son escasos en Mxico, aun cuando el pas es considerado un centro de distribucin. El [...] objetivo del presente trabajo fue generar ecuaciones alomtricas para estimar la biomasa area de rboles de Quercus laurina Humb. & Bonpl. y Q. crassifolia Humb. & Bonpl., en un bosque de la comunidad de Ixtln de Jurez, Oaxaca, Mxico. Se muestrearon 16 rboles por cada especie, distribuidos en seis categoras diamtricas y se determin la biomasa en fuste con corteza, ramas y follaje. Se evaluaron diferentes modelos de regresin con base en la bondad de ajuste y validez de sus indicadores estadsticos. Se eligi la ecuacin exponencial de la forma Biomasa = e[-?o+?1 ln(DN2xAT)], para calcular la biomasa (kg) en funcin al dimetro normal (DN, cm) y altura total (AT, m) de los rboles. La biomasa area total se estim en 100,15 Mg ha-1 para Q. laurina y 129,97 Mg ha-1 para Q. crassifolia. La distribucin proporcional de biomasa por compartimento de Q. laurina fue 82,9%; 14,9% y 2,2% para fustes, ramas y follaje, respectivamente, mientras que para Q. crassifolia la distribucin fue 82,3%; 16,0% y 1,7%; en el mismo orden. Abstract in english Estimating tree biomass is a means to determine the existing amounts of organic carbon in each of the tree components. Studies of biomass for Quercus species are scarce in Mexico, even though the country is considered a distribution center. The aim of this study was to generate allometric equations [...] for estimating aboveground biomass of trees Quercus laurina Humb. & Bonpl. and Q crassifolia Humb. & Bonpl., in a forest community of Ixtln de Jurez, Oaxaca, Mxico. Sixteen trees were sampled per species, distributed in six diameter categories and biomass was determined in stem bark, branches and foliage. Different regression models were evaluated based on fitness and validity of their statistical indicators. An exponential equation was chosen in the form of Biomasa = e[-?o+?1 ln(DN2xAT)], to calculate the biomass (kg) within a normal diameter (DN, cm) and total height (AT, m) of the trees. The total aboveground biomass was estimated at 100,15 Mg ha-1 for Q. laurina and 129,97 Mg ha-1 for Q. crassifolia. The proportional distribution of biomass per component of Q. laurina was 82,9%; 14,9% and 2,2% for stems, branches and foliage, respectively, while for Q. crassifolia the distribution was 82,3%; 16,0% and 1,7% in the same order.

  12. A importncia do limiar anaerbio e do consumo mximo de oxignio (VO2 mx.) em jogadores de futebol / The importance of the anaerobic threshold and maximum oxygen uptake (VO2 PEAK) for soccer players

    Scientific Electronic Library Online (English)

    Paulo Roberto Santos, Silva; Angela, Romano; Alberto Azevedo Alves, Teixeira; Ana Maria, Visconti; Carla Dal Maso Nunes, Roxo; Gilberto Silva, Machado; Jos Roberto Rivelino, Vidal; Lus Antonio, Inarra.

    1999-12-01

    Full Text Available O objetivo deste estudo foi fazer uma abordagem sobre a importncia do limiar anaerbio (LA) e o consumo mximo de oxignio (VO2mx.) em jogadores de futebol e comparar os resultados encontrados em nossos futebolistas com os da literatura especializada. Foram avaliados 18 jogadores de futebol profis [...] sional, com mdia de idade de 24 4 anos, peso de 72,5 5,9kg; estatura de 176,5 7,0cm e superfcie corprea de 1,91 0,15m. Todos os atletas foram avaliados aps um perodo de dois meses de treinamentos. Os futebolistas foram submetidos a teste mximo em esteira ergomtrica, utilizando-se protocolo escalonado e contnuo. A resposta de freqncia cardaca (FC) foi registrada por meio de um eletrocardigrafo (HeartWare) de 12 derivaes simultneas e, a presso arterial (PA), por meio de mtodo auscultatrio. A ventilao pulmonar (V E), o consumo de oxignio (VO2), a produo de dixido de carbono (VCO2) e a razo de troca respiratria (RER) foram avaliados por mtodo espiromtrico computadorizado respirao-a-respirao (MedGraphics Corporation [MGC]). Os seguintes resultados foram verificados: no (LA): [FC = 173,6 8,6bpm; VO2 = 55,78 5,93ml.kg.-1.min-1; velocidade = 14,6 1,0km.h-1]; no exerccio mximo [FC = 189,5 11,4bpm; V E = 134,1 15,9L.min-1; VO2mx. = 63,75 4,93ml.kg.-1.min-1; velocidade = 17,8 1,0km.h-1; Borg = 18,3 1,3 pontos]. Concluindo: Os resultados, comparados com os da literatura especializada na modalidade futebol, demonstraram que os ndices de LA e VO2mx. foram semelhantes e, at mesmo, superiores a vrios de estudos publicados sobre essas duas variveis em jogadores de futebol profissional. Entretanto, considerando as posies dos jogadores, no h um consenso definido sobre os ndices mais adequados de LA e VO2mx. em futebolistas, mas, sim, sugestes. Abstract in english The aim of this study was to make an approach on the importance of the anaerobic threshold (AT) and the peak oxygen uptake in soccer players, and compare the results found in players to those existing in the specialized literature. An evaluation was made in 18 professional soccer players aged 24 4 [...] ; weight 72.5 5.9 kg; height 176.5 7.0 cm, and body surface 1.91 0.15 m. Every athlete was evaluated after a 2 month training period. The soccer players were submitted to a maximum exercise test on treadmill, using incremental continuous protocol. The heart rate (HR) was recorded by means of an electrocardiograph (HeartWare) with 12 simultaneous leads and the arterial blood pressure (BP) by auscultation method. The pulmonary ventilation (V E), the oxygen uptake (VO2), the carbon dioxide production (VCO2) and the respiratory exchange rate (RER) were evaluated by means of the breath-by-breath spirometric computerized method (MedGraphics Corporation-MGC). The following results were verified in the AT: HR = 173.6 8.6 bpm; VO2 = 55.78 5.93 mlO2.kg-1.min-1; running velocity = 14.6 1.0 km.h-1; maximum exercise: HR = 189.5 11.4 bpm; V E = 134.1 15.9 L.min-1; VO2 peak = 63.75 4.93 mlO2.kg-1.min-1; maximum velocity = 17.8 1.0 km.h-1; Borg scale = 18.3 1.3 points. In conclusion, the results, when compared to those of specialized literature, proved the rate of AT and VO2 peak to be similar and even superior to several results published about such two variables in professional soccer players. Considering, however, the players' position, there is no definite consensus on the most adequate AT rates and VO2 peak in soccer players, but only suggestions.

  13. Water splitting reaction on NiO/InVO{sub 4} under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Hsin-Yu.; Chen, Yueh-Fang; Chen, Yu-Wen [Department of Chemical and Materials Engineering, Nanocatalysis Research Center, National Central University, Chung-Li 32054 (Taiwan)

    2007-01-15

    The photocatalytic activities of InVO{sub 4} and NiO/InVO{sub 4} for water splitting under visible light irradiation were investigated. NiO/InVO{sub 4} photocatalysts pretreated by different process were also investigated. The catalysts were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-vis spectroscopy. The photocatalytic reaction was carried out in a Pyrex glass reactor under visible light irradiation. The XRD patterns indicated that the InVO{sub 4} material was fully crystallized. SEM images showed that after loading NiO, many pin-holes were observed on the surface of the InVO{sub 4} particles. The particle size of the catalyst was about 5{mu} m. The band gap of InVO{sub 4} samples was 1.8 eV as estimated from UV-vis spectra. InVO{sub 4} was very active to produce H{sub 2}. The NiO/InVO{sub 4} catalyst which was reduced at 500 {sup circle} C for 2 h and then oxidized at ambient condition for 48 h gave the highest activity, which demonstrated that the pre-treatment process plays a key role in creating high catalytic performance for the NiO/InVO{sub 4} catalyst. (author)

  14. Optimization of thermochromic VO2-based structures with tunable thermal emissivity

    International Nuclear Information System (INIS)

    In this paper we design and simulate VO2/metal multilayers to obtain a large tunability of the thermal emissivity of IR filters in the typical MWIR window of many infrared cameras. The multilayer structure is optimized to realise a low-emissivity filter at high temperatures useful for military purposes. The values of tunability found for VO2/metal multilayers are larger than the value for a single thick layer of VO2. Innovative SiO2/VO2 synthetic opals are also investigated to enhance the optical tunability by combining the properties of a 3D periodic structure and the specific optical properties of vanadium dioxide.

  15. Temperature-agile and structure-tunable optical properties of VO2/Ag thin films

    International Nuclear Information System (INIS)

    By integrating together VO2's unique near-room-temperature (RT) semiconductor-metal (S-M) phase transition with a thin silver (Ag) layer's plasmonic properties, VO2/Ag multilayers could present a much enhanced optical transmission change when increasing the temperature from RT to over VO2's S-M phase-transition temperature. Changing VO2 and Ag layer thicknesses can also significantly tune their transmission and absorption properties, which could lead to a few useful designs in optoelectronic and energy-saving industries. (orig.)

  16. nc-VO2/Al2O3 nanocomposite films prepared by dual target magnetron sputtering

    International Nuclear Information System (INIS)

    A dual target magnetron sputtering system was used to synthesize nanocomposite films with VO2 nanocrystals embedded in Al2O3 matrix. Glancing incidence X-ray diffraction and high-resolution transmission electron microscopy reveal the formation of VO2 nanocrystallites with monoclinic structure. X-ray photoemission analysis confirmed that oxide particles predominantly possess VO2 stoichiometry. Valence band spectra acquired below and above transition temperature demonstrate that embedded VO2 particles exhibit a first-order monoclinic-to-tetragonal phase transition, however the band shape in a metallic state exhibits feature that is not characteristic for bulk material

  17. VV and VO2 defects in silicon studied with hybrid density functional theory

    KAUST Repository

    Christopoulos, Stavros Richard G

    2014-12-07

    The formation of VO (A-center), VV and VO2 defects in irradiated Czochralski-grown silicon (Si) is of technological importance. Recent theoretical studies have examined the formation and charge states of the A-center in detail. Here we use density functional theory employing hybrid functionals to analyze the formation of VV and VO2 defects. The formation energy as a function of the Fermi energy is calculated for all possible charge states. For the VV and VO2 defects double negatively charged and neutral states dominate, respectively.

  18. Time limit at VO2max velocity in elite crawl swimmers

    OpenAIRE

    Ricardo Fernandes; Kari Keskinen; Paulo Colao; Ana Querido; Leandro Machado; Pedro Morais; Daniel Novais; Daniel Marinho; Joo Paulo Vilas Boas Soares Campos

    2008-01-01

    he purpose of this study is to assess, with elite crawl swimmers, the time limit at the minimum velocity corresponding to maximal oxygen consumption (TLim-vVO2max), and to characterize its main determinants. Eight subjects performed an incremental test for vVO2max assessment and, forty-eight hours later, an all-out swim at vVO2max until exhaustion. VO2 was directly measured using a telemetric portable gas analyzer and a visual pacer was used to help the swimmers keeping the predetermined velo...

  19. IAX-Based Peer-to-Peer VoIP Architecture

    OpenAIRE

    Lazzez, Amor; Fredj, Ouissem Ben; Slimani, Thabet

    2013-01-01

    Nowadays, Voice over IP (VoIP) constitutes a privileged field of service innovation. One benefit of the VoIP technology is that it may be deployed using a centralized or a distributed architecture. One of the most efficient approaches used in the deployment of centralized VoIP systems is based on the use of IAX (Inter-Asterisk Exchange), an open-source signaling/data exchange protocol. Even though they are currently widely used, client-server VoIP systems suffer from many weaknesses such as t...

  20. EPR study of VO2+ doped glycine zinc sulphate single crystal

    Science.gov (United States)

    Prabakaran, R.; Subramanian, P.

    2015-06-01

    Single crystals Of GZS:VO2+ were grown by slow evaporation of solvent at room temperature. The EPR study was carried out at room temperature. Single crystal rotations in each of the three mutually orthogonal planes indicate single site occupation of VO2+ in the lattice. g and A tensors were calculated from the recorded EPR spectra. The principal values of g and A indicates existence of rhombic symmetry around the VO2+ ion. From the direction cosines of the g and A tensors, the locations of VO2+ in the lattice have been identified as substitutional site.

  1. TAPAS, a VO archive at the IRAM 30-m telescope

    Science.gov (United States)

    Leon, Stephane; Espigares, Victor; Ruz, Jos Enrique; Verdes-Montenegro, Lourdes; Mauersberger, Rainer; Brunswig, Walter; Kramer, Carsten; Santander-Vela, Juan de Dios; Wiesemeyer, Helmut

    2012-07-01

    Astronomical observatories are today generating increasingly large volumes of data. For an efficient use of them, databases have been built following the standards proposed by the International Virtual Observatory Alliance (IVOA), providing a common protocol to query them and make them interoperable. The IRAM 30-m radio telescope, located in Sierra Nevada (Granada, Spain) is a millimeter wavelength telescope with a constantly renewed, extensive choice of instruments, and capable of covering the frequency range between 80 and 370 GHz. It is continuously producing a large amount of data thanks to the more than 200 scientific projects observed each year. The TAPAS archive at the IRAM 30-m telescope is aimed to provide public access to the headers describing the observations performed with the telescope, according to a defined data policy, making as well the technical data available to the IRAM staff members. A special emphasis has been made to make it Virtual Observatory (VO) compliant, and to offer a VO compliant web interface allowing to make the information available to the scientific community. TAPAS is built using the Django Python framework on top of a relational MySQL database, and is fully integrated with the telescope control system. The TAPAS data model (DM) is based on the Radio Astronomical DAta Model for Single dish radio telescopes (RADAMS), to allow for easy integration into the VO infrastructure. A metadata modeling layer is used by the data-filler to allow an implementation free from assumptions about the control system and the underlying database. TAPAS and its public web interface ( http://tapas.iram.es ) provides a scalable system that can evolve with new instruments and observing modes. A meta description of the DM has been introduced in TAPAS in order to both avoid undesired coupling between the code and the DM and to provide a better management of the archive. A subset of the header data stored in TAPAS will be made available at the CDS.

  2. Ultrafast dynamics during the photoinduced phase transition in VO2

    Science.gov (United States)

    Wegkamp, Daniel; Sthler, Julia

    2015-12-01

    The phase transition of VO2 from a monoclinic insulator to a rutile metal, which occurs thermally at TC = 340 K, can also be driven by strong photoexcitation. The ultrafast dynamics during this photoinduced phase transition (PIPT) have attracted great scientific attention for decades, as this approach promises to answer the question of whether the insulator-to-metal (IMT) transition is caused by electronic or crystallographic processes through disentanglement of the different contributions in the time domain. We review our recent results achieved by femtosecond time-resolved photoelectron, optical, and coherent phonon spectroscopy and discuss them within the framework of a selection of latest, complementary studies of the ultrafast PIPT in VO2. We show that the population change of electrons and holes caused by photoexcitation launches a highly non-equilibrium plasma phase characterized by enhanced screening due to quasi-free carriers and followed by two branches of non-equilibrium dynamics: (i) an instantaneous (within the time resolution) collapse of the insulating gap that precedes charge carrier relaxation and significant ionic motion and (ii) an instantaneous lattice potential symmetry change that represents the onset of the crystallographic phase transition through ionic motion on longer timescales. We discuss the interconnection between these two non-thermal pathways with particular focus on the meaning of the critical fluence of the PIPT in different types of experiments. Based on this, we conclude that the PIPT threshold identified in optical experiments is most probably determined by the excitation density required to drive the lattice potential change rather than the IMT. These considerations suggest that the IMT can be driven by weaker excitation, predicting a transiently metallic, monoclinic state of VO2 that is not stabilized by the non-thermal structural transition and, thus, decays on ultrafast timescales.

  3. La biomasa de los cultivos en el oecosistema. Sus beneficios agroecolgicos / The biomass of the cultivations in the agroecosistema. Its benefits agroecological

    Scientific Electronic Library Online (English)

    Anirebis, Martnez Romero; Angel, Leyva Galn.

    2014-03-01

    Full Text Available La biomasa es el resultado de la transformacin de la energa solar en energa qumica. El hombre a travs de la historia la ha utilizado no solo para su alimentacin sino tambin para la alimentacin de sus animales. Los avances de la ciencia promovieron el desarrollo agrario basado en la revoluci [...] n verde, la cual solo promueve la produccin de alimentos ya sea de uso humano o animal, marginando la importancia de la biomasa como enriquecedor del recurso suelo al disponerse de los insumos necesarios para sustituir su fertilidad natural. En la actualidad la produccin y conservacin de la biomasa de cualquier cultivo cobra una importancia trascendente; por que ello contribuye, adems, a la proteccin medioambiental a travs de la captura de carbono. El presente trabajo tuvo como objetivo demostrar la importancia que proporciona la biomasa generalmente no alimenticia para los humanos, a fin de emplearla no solo como alimento animal, sino tambin como enriquecedora del recurso natural suelo. Las investigaciones realizadas en Cuba sobre el tema es pobre, aun cuando en la actualidad resulta de gran importancia encontrar variantes que permitan profundizar en la produccin de biomasa en su relacin con el medio ambiente. Finalmente se exponen los resultados preliminares sobre produccin de biomasa a partir de la agrobiodiversidad presente en los escenarios productivos, a la vez que se reflexiona sobre la importancia del tema para futuras investigaciones. Abstract in english Biomass is the result of the transformation of solar energy into chemical energy. The man throughout history has used not only for food but also for feeding their animals. The progress of science promoted agricultural development based on the green revolution, which only promotes the production of e [...] ither food or feed, marginalizing the importance of biomass as enriching the soil resources available inputs needed to replace their fertility natural. At present the production and preservation of any crop biomass becomes transcendent importance, because it also contributes to environmental protection through carbon sequestration. This study aimed to show the importance of providing non-food biomass generally for humans to use it not only as animal feed but also as a natural resource rich soil. Research in Cuba on the subject is poor, even though today is very important to find alternatives to deepen in the production of biomass in relation to the environment. Finally, we present preliminary results on the production of biomass from agricultural biodiversity present in production scenarios, while reflecting on the important question for future research.

  4. Biomasa fúngica y bacteriana como indicadoras del secuestro de C en suelos de sabanas sustituidos por pinares en Uverito, Venezuela

    Directory of Open Access Journals (Sweden)

    Magalis Zabala

    2010-09-01

    Full Text Available Cualquier transformación de un ecosistema natural a un sistema agrícola o forestal conduce a una modificación importante no sólo del pool del carbono total, sino también del carbono asociado con la biomasa microbiana. Su cuantificación es importante en la determinación del impacto de las prácticas agrícolas y el cambio de uso de la tierra sobre la calidad del suelo. El objetivo de este estudio fue determinar, a través del método de inhibición selectiva, la biomasa fúngica y bacteriana y la relación (H:B en suelos de sabana nativa sustituidos por pinares (Pinus caribaea var. hondurensis, para establecer si éstos parámetros son indicadores sensibles de cambios en el contenido de carbono en suelos de Uverito, Venezuela. La relación de aditividad del inhibidor (RAI y la inhibición total por efecto combinado del inhibidor (ITC se llevaron a cabo para determinar, si los inhibidores microbianos tuvieron actividad sobre otros organismos para los cuales éstos no estaban destinados. La cuantificación de la biomasa fúngica y bacteriana se llevó a cabo mediante el uso de la cycloheximida como inhibidor fúngico, y la estreptomicina y el cloranfenicol como inhibidores bacterianos. Esta investigación evidencia que este cambio de uso de la tierra ejerció un efecto significativo sobre la biomasa microbiana del suelo, y muestra que en el sistema de pinares existe una dominancia del componente fúngico, en contraste con la sabana nativa, en la cual domina la biomasa bacteriana. La sustitución de la sabana nativa por plantaciones de pino en Uverito, promueve un mayor secuestro del carbono en el suelo. Los valores de la relación de aditividad del inhibidor (RAI tanto para la sabana nativa como para el sistema de pinares, resultaron ambos >1.0. La inhibición total combinada (ITC resultó menor en el sistema de pinares; a partir de lo cual, es posible inferir que una elevada proporción de la biomasa microbiana fue afectada por la combinación de los inhibidores.

  5. Comprehensive picture of VO2 from band theory

    KAUST Repository

    Zhu, Zhiyong

    2012-08-28

    The structural, electronic, and magnetic features of the metal-insulator transition from the tetragonal rutile (R) to the monoclinic (M1) phase of VO2 are well reproduced by band theory using the modified Becke-Johnson exchange potential. Based on this description, we identify a tendency for monoclinic charge ordering in the R phase due to electronic correlations as the origin of the phase transition. Whereas, the structural changes are crucial for the gap opening in the M1 phase, spin degeneracy in both phases is stabilized by correlation-induced delocalization of the V3d electrons.

  6. Analysis of VoIP Traffic with Multiple Packet Transfer

    Directory of Open Access Journals (Sweden)

    Tara Chand, Vishal Srivastava

    2012-06-01

    Full Text Available Voice over Internet Protocol (VoIP is a form of voice communication. Today Wireless LANs are providing a cost effective alternative for the voice communication. Initially the wireless access protocols are not suitable for the voice communication. Subsequently, new techniques are developed for the real time voice communication. In voice communication the delay is an important factor. In this paper a new technique is proposed for the voice over IEEE 802.11 WLANs. The proposed technique is compared with Modified ICF

  7. Study of LiMgVO4 electrical conductivity mechanism

    OpenAIRE

    Paraskeva, C; Kazakopoulos, A.; Chrissafis, K.; Kalogirou, O.

    2010-01-01

    This paper deals with impedance spectroscopy on single-phase polycrystalline LiMgVO4 in the temperature range of 25–500 °C. Thermogravimetric measurements show a weight loss of 2.7% in the temperature range between 25 °C and 175 °C due to humidity desorption. A conductivity mechanism along the grain boundaries (agb) is identified in the specific temperature range and is attributed to a reversible humidity absorption–desorption mechanism. Equivalent circuits are drawn using the results of the ...

  8. Content Delivery System for Optimal VoD Streaming

    OpenAIRE

    Gramatikov, Sasho; Jaureguizar Nez, Fernando; Cabrera Quesada, Julian; Garca Santos, Narciso

    2011-01-01

    The demand of video contents has rapidly increased in the past years as a result of the wide deployment of IPTV and the variety of services offered by the network operators. One of the services that has especially become attractive to the customers is real-time video on demand (VoD) because it offers an immediate streaming of a large variety of video contents. The price that the operators have to pay for this convenience is the increased traffic in the networks, which are becoming more conges...

  9. Zircon to monazite phase transition in CeVO4

    OpenAIRE

    Panchal, V; Lopez-Moreno, S.; Santamaria-Perez, D.; Errandonea, D.; Manjon, F. J.; P. Rodriguez-Hernandez; A. Munoz; Achary, S.N.; Tyagi, A.K.

    2011-01-01

    X-ray diffraction and Raman-scattering measurements on cerium vanadate have been performed up to 12 and 16 GPa, respectively. Experiments reveal that at 5.3 GPa the onset of a pressure-induced irreversible phase transition from the zircon to the monazite structure. Beyond this pressure, diffraction peaks and Raman-active modes of the monazite phase are measured. The zircon to monazite transition in CeVO4 is distinctive among the other rare-earth orthovanadates. We also obser...

  10. VoIP Steganography and Its Detection - A Survey

    CERN Document Server

    Mazurczyk, Wojciech

    2012-01-01

    Steganography is an ancient art that encompasses various techniques of information hiding, the aim of which is to secret information into a carrier message. Steganographic methods are usually aimed at hiding the very existence of the communication. Due to the rise in popularity of IP telephony, together with the large volume of data and variety of protocols involved, it is currently attracting the attention of the research community as a perfect carrier for steganographic purposes. This paper is a survey of the existing VoIP steganography (steganophony) methods and their countermeasures.

  11. VoIP Technology: Investigation of QoS and Security Issues

    Directory of Open Access Journals (Sweden)

    Amor Lazzez

    2014-06-01

    Full Text Available Voice over IP (VoIP is the technology allowing voice traffic transmission as data packets over a private or a public IP network. VoIP allows significant benefits for customers and communication services providers. The main are cost savings, rich media service, phone and service portability and mobility, and the integration with other applications. Nevertheless, the deployment of the VoIP technology encounters many challenges such as architecture complexity, interoperability problems, QoS concerns, and security issues. Due to the inability of the IP networking technology to support the stringent QoS constraints of voice traffic, and the incapability of traditional security mechanisms to adequately protect VoIP systems from recent intelligent attacks, QoS and security issues are considered as the most serious challenges for successful deployment of the VoIP technology. The aim of this paper is to carry out a deep analysis of the security issues and QoS concerns of the VoIP technology. Firstly, we present a brief overview about the VoIP technology. Then, we discuss the QoS problems encountering the deployment of the VoIP technology. The presented discussion mainly address the QoS issues related to the use of the IP networking technology, the QoS concerns related to voice clarity, and the QoS mechanisms proposed to support voice traffic QoS constraints. After that, we investigate the security issues of the VoIP technology. The presented investigation mainly address the vulnerabilities and security attacks of VoIP systems, as well as the countermeasures that should be considered to help the deployment of secured VoIP systems.

  12. Extraction Of Electronic Evidence From VoIP: Identification & Analysis Of Digital Speech

    Directory of Open Access Journals (Sweden)

    David Irwin

    2012-09-01

    Full Text Available The Voice over Internet Protocol (VoIP is increasing in popularity as a cost effective and efficient means of making telephone calls via the Internet. However, VoIP may also be an attractive method of communication to criminals as their true identity may be hidden and voice and video communications are encrypted as they are deployed across the Internet. This produces in a new set of challenges for forensic analysts compared with traditional wire-tapping of the Public Switched Telephone Network (PSTN infrastructure, which is not applicable to VoIP. Therefore, other methods of recovering electronic evidence from VoIP are required.  This research investigates the analysis and recovery of digitised human, which persists in computer memory after a VoIP call.This paper proposes a proof of concept how remnants of digitised human speech from a VoIP call may be identified within a forensic memory capture based on how the human voice is detected via a microphone and encoded to a digital format using the sound card of your personal computer. This digital format is unencrypted whist processed in Random Access Memory (RAM before it is passed to the VoIP application for encryption and  transmission over the Internet. Similarly, an incoming encrypted VoIP call is decrypted by the VoIP application and passes through RAM unencrypted in order to be played via the speaker output.A series of controlled tests were undertaken whereby RAM captures were analysed for remnants of digital speech after a VoIP audio call with known conversation. The identification and analysis of digital speech from RAM attempts to construct an automatic process for the identification and subsequent reconstruction of the audio content of a VoIP call.

  13. Modelos para estimar la biomasa de especies nativas en plantaciones y bosques secundarios en la zona Caribe de Costa Rica Models for biomass estimation in native forest tree plantations and secondary forests in the Costa Rican Caribbean Region

    OpenAIRE

    William Fonseca G; Federico Alice G; Jos Mara Rey B

    2009-01-01

    El uso de los ecosistemas forestales como sumideros y reservorios de carbono es cada da ms aceptado. An as, la informacin fidedigna sobre su crecimiento en biomasa y la capacidad de captura y de almacenamiento de CO2 es insuficiente para proponer formas de compensacin a los propietarios de bosques. El objetivo de este trabajo fue construir modelos para estimar la biomasa del rbol en plantaciones de Hieronyma alchorneoides, Vochysia guatemalensis y para un grupo de 35 especies en bosque...

  14. AstroStat - A VO Tool for Statistical Analysis

    CERN Document Server

    Kembhavi, Ajit K; Kale, Tejas; Jagade, Santosh; Vibhute, Ajay; Garg, Prerak; Vaghmare, Kaustubh; Navelkar, Sharmad; Agrawal, Tushar; Nandrekar, Deoyani; Shaikh, Mohasin

    2015-01-01

    AstroStat is an easy-to-use tool for performing statistical analysis on data. It has been designed to be compatible with Virtual Observatory (VO) standards thus enabling it to become an integral part of the currently available collection of VO tools. A user can load data in a variety of formats into AstroStat and perform various statistical tests using a menu driven interface. Behind the scenes, all analysis is done using the public domain statistical software - R and the output returned is presented in a neatly formatted form to the user. The analyses performable include exploratory tests, visualizations, distribution fitting, correlation & causation, hypothesis testing, multivariate analysis and clustering. The tool is available in two versions with identical interface and features - as a web service that can be run using any standard browser and as an offline application. AstroStat will provide an easy-to-use interface which can allow for both fetching data and performing power statistical analysis on ...

  15. Structural analysis of strained LaVO3 thin films.

    Science.gov (United States)

    Rotella, H; Copie, O; Steciuk, G; Ouerdane, H; Boullay, P; Roussel, P; Morales, M; David, A; Pautrat, A; Mercey, B; Lutterotti, L; Chateigner, D; Prellier, W

    2015-05-01

    While structure refinement is routinely achieved for simple bulk materials, the accurate structural determination still poses challenges for thin films due on the one hand to the small amount of material deposited on the thicker substrate and, on the other hand, to the intricate epitaxial relationships that substantially complicate standard x-ray diffraction analysis. Using both electron and x-ray diffraction, we analyze the crystal structure of epitaxial LaVO3 thin films grown on (1?0?0)-oriented SrTiO3. Transmission electron microscopy study reveals that the thin films are epitaxially grown on SrTiO3 and points to the presence of 90 oriented domains. The mapping of the reciprocal space obtained by high resolution x-ray diffraction permits refinement of the lattice parameters. We finally deduce that strain accommodation imposes a monoclinic structure onto the LaVO3 film. The reciprocal space maps are numerically processed and the extracted data computed to refine the atomic positions, which are compared to those obtained using precession electron diffraction tomography. PMID:25765433

  16. Chapter 30: Crossmatching Data in the VO: BCG Line Ratios

    Science.gov (United States)

    Miller, C. J.; Krughoff, K. S.

    In this chapter, we will determine the emission line ratios of Brightest Cluster Galaxies (BCGs) in a sample drawn the Sloan Digital Sky Survey C4 galaxy cluster catalog (Miller et al. 2005). These line ratios can be used to provide some insight on whether these galaxies are star-forming or contain an Active Galactic Nucleus. We will utilize a series of VO tools: Open SkyPortal, TOPCAT and VOPlot. BCGs can be defined in different ways and are often synonymous with brightest central galaxies or even cD galaxies (galaxies with optically extended light envelopes). BCGs are the most massive galaxies and their formation and evolution are a popular and current research topic (Linden et al. 2006, Bernardi et al. 2006, Lauer et al. 2006). They have been studied for some time (Sandage 1972, Ostriker & Tremain 1975, White 1976, Thuan & Romanishin 1981, Merritt 1985, Postman and Lauer 1995, among many others). In this VO research example, our aim is to take a list of galaxies known to lie within the footprint of the SDSS, which provides us with the possibility that some of these galaxies will have measured spectra from the SDSS spectroscopic pipeline. Thus, there is some prerequisite knowledge: 1) Many bright SDSS galaxies have spectra with measured emission line properties; 2) Our catalog of Brightest Cluster Galaxies has some overlap with the SDSS footprint. Taken together, we can crossmatch our catalog to the SDSS spectroscopic galaxy data in order to extract any available emission-line information.

  17. Efecto de fertilizacin nitrogenada en la produccin de biomasa y calidad de aceite esencial en Lippia alba (Miller, Pronto alivio.

    Directory of Open Access Journals (Sweden)

    Snchez O. M.

    2004-04-01

    Full Text Available En el Campo Experimental de la Universidad Nacional de Colombia sede Palmira (CEUNP se realiz un ensayo para evaluar el efecto de la fertilizacin nitrogenada, aplicando dos fuentes (gallinaza y urea en dos niveles (50 y 100 kg/ha de nitrgeno y dos frecuencias de corte (dos y cuatro meses. En el lote experimental se situaron 15 parcelas, en un diseo de bloques completos al azar, con cinco tratamientos y tres repeticiones. Para el anlisis de la informacin se utiliz el programa estadstico SAS. El mximo rendimiento de biomasa y aceites esenciales se obtuvo con la aplicacin de 100 kg/ha de nitrgeno en forma de urea y la frecuencia de corte cada dos meses. Los niveles de extraccin de Lippia alba en nitrgeno variaron entre 79.7 y 128.5; fsforo entre 24.5 y 30.5; potasio entre 114.6 y 138.8 y calcio entre 100 y 150 kg/ha. El aceite esencial estuvo compuesto mayoritariamente por carvona y limoneno. Palabras claves: Fertilizacin nitrogenada, Lippia alba, Rendimientos biomasa, aceites esenciales, pronto alivio. ABSTRACT Nitrogenous fertilization effects in the Lippia alba production and quality. In the Experimental Center of the National University of Colombia-Palmira (CEUNP a experiment was realized to evaluate the effect of the nitrogenous fertilization, using two sources (gallinaza and urea at two levels (50 and 100 kg/ha of nitrogen and two cutting frequencies (each two and four months. In the experimental area 15 plots were planted, in a randomized Complete Blocks design random (RCBD with five treatments and three repetitions to measure the following variables: production of fresh matter, content of dry matter, nutrients extraction and content of essential oils. The analysis of variance used the statistical program SAS. The maximum yield of biomass and essential was obtained oils combining the fertilization with 100 kg/ha of nitrogen as urea and the cutting frequency every of two months. The levels of nutrients extraction of Lippia alba varied between 79.7 and 128.5 kg/ha of nitrogen, 24.5 and 30.5 kg/ha of phosphorus, 114.6 and 138.8 Kg/ha of potassium and between 100 y 150 kg/ha of Calcium. The phytochemical analyses showed that the essential oil was mainly composed by carvona and limoneno. Key words: Nitrogenous Fertilization, Lippia alba, yields, biomass, essential oils.

  18. Variaciones de abundancia y biomasa del zooplancton en un embalse tropical oligo-mesotrfico del norte de Venezuela

    Directory of Open Access Journals (Sweden)

    Sandra Merayo

    2010-06-01

    Full Text Available La abundancia del zooplancton en los embalses est determinada principalmente por la velocidad y el contenido del agua, pero se sabe relativamente poco sobre los embalses tropicales. Se estudi la distribucin temporal y espacial de la abundancia y la biomasa del zooplancton en el eje longitudinal del embalse de Clavellinos, en el norte de Venezuela, entre octubre 2006 y septiembre 2007. El zooplancton fue recolectado en el estrato oxigenado con una red de plancton. Un total de 16 taxones fueron identificados: Copepoda, Cladocera, Rotifera, Ostracoda y Diptera. Thermocyclops decipiens (Copepoda, Cyclopoida domin la comunidad, mientras que los rotferos fueron los ms diversos, con 10 especies. La abundancia del zooplancton vari de 31 a 101ind/l en E1, 36 a 84ind/l en E2, y, de 30 a 250ind/L en el E3. La biomasa vari de 97,4 a 1406.3?g/l en E1, 108,5 a 397.2?g/l en E2, y de 25,9 a 763.9?g/l en el E3. Esta comunidad de zooplancton pareci? responder a las variaciones ambientales en el embalse, m?s que a las variaciones en la disponibilidad de recursos.Variations of zooplankton abundance and biomass in a tropical oligo-mesotrophic reservoir in Northern Venezuela. Zooplankton abundance in reservoirs is mainly determined by the speed and content of the water, but relatively little is known regarding tropical reservoirs. We studied the seasonal and spatial distribution of zooplankton abundance and biomass along the longitudinal axis of Clavellinos reservoir, northern Venezuela, from October 2006 to September 2007. Zooplankton was collected from the oxygenated layer using a plankton net. A total of 16 taxa were identified: Copepoda, Cladocera, Rotifera, Ostracoda and Diptera. Thermocyclops decipiens (Copepoda, Cyclopoida dominated the community, while rotifers were the most diverse, with 10 species. Zooplankton abundance varied from 31 to 101ind/L in E1, 36 to 84ind/L in E2, and, from 30 to 250ind/L in E3. Biomass varied from 97.4 to 1406.3?g/l in E1, 108.5 to 397.2?g/l in E2, and from 25.9 to 763.9?g/l in E3. This zooplankton community seems to respond to environmental variations in the reservoir, rather than to variations in resource availability. Rev. Biol. Trop. 58 (2: 603-619. Epub 2010 June 02.

  19. Biomasa acumulada e intercambio gaseoso en maz proveniente de semilla de diferente tamao bajo humedad favorable y restringida: (con 3 tablas)

    Scientific Electronic Library Online (English)

    Jos Alberto, Lpez-Santilln; Sergio, Castro-Nava; Carlos, Trejo-Lpez; Ma. Del Carmen, Mendoza-Castillo; Joaqun, Ortiz-Cereceres.

    2004-12-01

    Full Text Available Se evalu la velocidad de germinacin y el crecimiento de plntulas de maz provenientes de semilla de dos diferentes tamaos para determinarlas diferencias en la produccin de biomasa durante la etapa vegetativa y estimar los efectos de una condicin diferente de disponibilidad de humedad sobre el [...] estatus fisiolgico de la plntula. Una mayor cantidad de biomasa en el endospermo y en el embrin de las semillas permiti una mayor disponibilidad de reservas durante la etapa posterior a la germinacin y anterior a la emergencia, dando como resultado un mayor vigor inicial en las plntulas evaluadas, y en consecuencia una mayor acumulacin de biomasa, tanto radical como area, durante la etapa vegetativa. La presencia de una restriccin de humedad durante la germinacin y la etapa vegetativa de estas plantas provoc un decremento de 72.6% en la acumulacin de biomasa en la parte area, tanto en plantas provenientes de semilla grande como chica, como consecuencia de una disminucin de diversos procesos fisiolgicos como son la conductancia estomtica, transpiracin y tasa fotosinttica. Abstract in english The germination speed and seedling growth of maize seed of two different sizes was evaluated. To determine the differences in the biomass production during the vegetative stage from different seed size, considering the effects of humidity on seedling physiological status. A larger amount of biomass [...] in endosperm and embryo allowed greater availability of reserves during the later stage of the germination; previous to emergency resulting in a high seedling vigor and a most accumulation of as much radical biomass as aerial during the vegetative stage, the water restriction during the germination and the vegetative stage of these plants caused a decrement of 72,6% in the aerial biomass accumulation in big and small seed plants, due to a diminution from diverse physiological processes such as stomatic conductance, transpiration and photosynthetic rate.

  20. Cambios en el porcentaje de sodio intercambiable (psi) y la relacin de absorcin de sodio (ras) de un suelo y su influencia en la actividad y biomasa microbiana

    OpenAIRE

    Torrente Trujillo Armando; Gasca Cesar A.; Menjivar Juan Carlos

    2011-01-01

    Con el objetivo de evaluar los cambios en el PSI, la RAS y su influencia en la actividad y biomasa microbiana del suelo, se aplicaron diversas concentraciones de vinaza como enmienda procedente de la industria de alcohol carburante, sobre un suelo afectado por sodicidad con severas limitaciones en las condiciones fsicas, qumicas y biolgicas. Se aplic un diseo en bloques completos al azar que incluye cuatro tratamientos y tres repeticiones, y muestreos de suelo al inicio ...

  1. Produccin de biomasa verde y calidad de aceites esenciales de palmarosa (Cymbopogon martini Roxb. con aplicacin de fertilizantes de sntesis y orgnicos

    Directory of Open Access Journals (Sweden)

    Javier Alberto Pinzn-Torres

    2014-12-01

    Full Text Available El uso de fertilizantes minerales en cultivos de Cymbopogon martini Roxb. (Palmarosa con el fin de incrementar la biomasa y el rendimiento de aceite esencial (AE es una prctica cada vez ms frecuente. Este aceite es rico en geraniol y acetato de geranilo, molculas con alto valor en las industrias de productos cosmticos y farmacutica. Las plantas fueron obtenidas del Centro Nacional de Investigacin Agroindustrial de Plantas Aromaticas y Medicinales de la Universidad Industrial de Santander (UIS (Cenivam (07 08' 31.68"N, 73 07' 06.14O; 988 m.s.n.m., Santander, Colombia. El objetivo del estudio fue evaluar la productividad de biomasa y analizar la calidad y el rendimiento de los aceites esenciales (AE de este cultivo con la aplicacin de tres tipos de fertilizantes qumico: Nutrimon 14-14-14, NPK granulado (10% N, 14% P2O5 , 14% K2O, en dosis de 2, 4 y 6 g/planta, ms un tratamiento con 400 g de un fertilizante orgnico,. Se utiliz un diseo de bloques completos al azar, con trece tratamientos y tres cosechas de tres plantas cada una como repeticiones. Los datos fueron sometidos a anlisis de variancia con comparacin de las medias por la prueba de Tukey a 5% de probabilidad. No se observaron correlaciones entre biomasa y rendimiento del AE en funcin del tipo del fertilizante aplicado, lo que sugiri que los tratamientos que incrementaron la produccin de biomasa no necesariamente representaron mayor rendimiento del AE y viceversa. Se encontr que los fertilizantes orgnicos son ideales para este cultivo, ya que favorecieron rendimientos relativamente altos en aceite, con altos porcentajes de geraniol y acetato de geranilo.

  2. Relacin entre la composicin y biomasa de la comunidad de macroinvertebrados acuticos y las variables fsicas y qumicas en el humedal Jaboque Bogot-Colombia

    OpenAIRE

    Rivera Usme, John Jader

    2011-01-01

    Durante los meses de abril del 2009 a enero del 2010 se estudiaron las condiciones biolgicas y ecolgicas del humedal Jaboque por medio de la medicin de variables fsicas y qumicas en periodos climticos contrastantes y la evaluacin de la composicin, biomasa y estructura trfica de los macroinvertebrados. Se registr una composicin faunstica formada por 26 gneros confirmados y nueve aun por confirmar. En las pocas de menores lluvias se registr la menor riqueza y mayor...

  3. Desarrollo, produccin de biomasa y contenido de flavonoides en plantas de Cuphea carthagenensis (Jacq.) Macbride (Lythraceae), sometidas a distintos sustratos, sistemas de irrigacin y poda de las hojas

    OpenAIRE

    Dezanet, Andr; Baier Krepsky, Patrcia; Mathioni, Sandra Marisa; Rocha Faras, Mareni; Nodari, Rubens Onofre

    2007-01-01

    Este estudio evalu los efectos de cuatro sustratos de suelo, dos sistemas de irrigacin y tres intensidades de poda de las hojas sobre el desarrollo de la planta, produccin de biomasa y contenido de quercetina-3-sulfato en Cuphea carthagenensis (Jacq.) MacBride (Lythraceae). El sustrato 50% de tierra frtil comercial + 50% de arena promovi los valores ms altos para todos los parmetros analizados, excepto longitud de raz. La tcnica de poda 2/3 de intensidad puede ser utilizada como una ...

  4. Efecto de la fertilizacin sobre la produccin de biomasa y la absorcin de nutrientes en Brachiaria decumbens y Brachiaria hbrido Mulato

    OpenAIRE

    Navajas Martnez, Vctor Manuel

    2011-01-01

    Los suelos utilizados para la actividad ganadera generalmente son de baja fertilidad y alta acidez, lo cual genera bajas productividades. Existen cultivares de pasto Brachiaria que se adaptan a dichas condiciones adversas, pero se desconoce su comportamiento en condiciones agroecolgicas de Barrancabermeja, Santander. El objetivo de esta investigacin fue evaluar el efecto de la fertilizacin sobre la produccin de biomasa y la absorcin de nutrientes por los pastos Brachiaria decumbens y ...

  5. Cambio en el PSI y la RAS de un suelo y su influencia en la actividad biolgica y la biomasa microbiana

    OpenAIRE

    Gasca Valderrama, Cesar Augusto

    2010-01-01

    Con el objetivo de evaluar los cambios en el PSI, la RAS y su influencia en la actividad y biomasa mircrobiana del suelo, se aplicaron diversos tratamientos con vinaza como enmienda procedente de la industria de alcohol carburante, sobre un suelo afectado por sodicidad con severas limitaciones en las condiciones fsicas, qumicas y biolgicas. Se aplic diseo en bloques completos al azar con cuatro tratamientos y tres repeticiones, y se evaluaron las propiedades del suelo: Actividad biolgic...

  6. Selective synthesis of monazite- and zircon-type LaVO(4) nanocrystals.

    Science.gov (United States)

    Jia, Chun-Jiang; Sun, Ling-Dong; You, Li-Ping; Jiang, Xiao-Cheng; Luo, Feng; Pang, Yu-Cheng; Yan, Chun-Hua

    2005-03-01

    Pure monoclinic (m-) and tetragonal phased (t-) LaVO(4) nanocrystals could be obtained by a hydrothermal method in a controllable way with additives. It is found that chelating ligands, such as ethylenediaminetetraacetic acid [EDTA or H(4)L, where L(4-) = (CH(2)COO)(2)N(CH(2))(2)N(CH(2)COO)(2)(4-)], favor the formation of t-LaVO(4) and can induce the polymorph transformation from stable m-LaVO(4) to metastable t-LaVO(4). Further studies demonstrated the important roles of chelating ligands in this transformation process. Careful investigation over the phase transition from t- to m-LaVO(4) was also conducted with high-temperature X-ray diffraction (HTXRD) studies. The phase transition occurred at 850 degrees C, which is about 250 degrees C higher than for the bulk. The enhanced thermal stability of the nanosized metastable t-LaVO(4) may come from the small size effect. Our capability of obtaining and stabilizing t-LaVO(4) not only benefits the wider applications based on LaVO(4) due to the improved luminescent and catalytic performance but also provides a new idea in the studies of polymorph control and selective synthesis of inorganic materials. PMID:16851354

  7. VO2 kinetics and performance in soccer players after intense training and inactivity

    DEFF Research Database (Denmark)

    Christensen, Peter Mller; Krustrup, Peter; Gunnarsson, Thomas P.; Kiilerich, Kristian; Nybo, Lars; Bangsbo, Jens

    2011-01-01

    PURPOSE:: To examine the effects of a short-term period with intensified training or training cessation of trained soccer players on VO2 kinetics at 75% maximal aerobic speed (MAS), oxidative enzymes and performance in repeated high intensity exercise. METHODS:: After the last match of the season...... refrained from training. RESULTS:: For TC, VO2 kinetics became slower (P...

  8. The VO-5 fan for the coal industry and for agriculture

    Energy Technology Data Exchange (ETDEWEB)

    Raskin, I.A.; Ivanov, S.K.; Karminskiy, V.N.

    1984-01-01

    The characteristics, description and results of tests of the VO-5 fan are cited. It has a diameter of 5.00 meters and is designed for use on the surface of mines and for drying grain in grain storage facilities. Series production of the VO-5 began in 1982.

  9. Indirect estimation of VO2max in athletes by ACSMs equation: valid or not?

    OpenAIRE

    Koutlianos, N; Dimitros, E; Metaxas, T; Cansiz, M; Deligiannis, AS; Kouidi, E

    2013-01-01

    Aim: The purpose of this study was to assess the indirect calculation of VO2max using ACSMs equation for Bruce protocol in athletes of different sports and to compare with the directly measured; secondly to develop regression models predicting VO2 max in athletes.

  10. EFECTO DEL VERMIABONO EN CRECIMIENTO Y ACUMULACIÓN DE BIOMASA EN Aeschynomene americana L. EN BANCOS DE MINERÍA A CIELO ABIERTO

    Directory of Open Access Journals (Sweden)

    Rosa de Lourdes Romo Campos

    2009-01-01

    instauraron parcelas de 1 m2 a las que se les adicionó 1 kg m-2 de vermiabono (compost de lombriz Eisenia foetida y se compararon con un testigo al cual no se le aplicó vermiabono. Después de un ciclo de cultivo se observó que no existieron diferencias en la sobrevivencia de las plantas (10 y 16%, pero sí en la tasa de crecimiento, debido a que las plantas tratadas con vermiabono lograron alturas ocho veces mayores que el tratamiento testigo. Esta diferencia también se observó en la acumulación de biomasa al final del ciclo de vida de la planta (120 días, puesto que las plantas tratadas acumularon 21.7 g m-2 de materia seca; de los cuales 7 g m-2 se destinaron a la producción del fruto, en contraste con las plantas del tratamiento testigo que acumularon 1.5 g m-2 de biomasa y sólo 0.2 g m-2 se asignaron a los frutos, por lo que estas plantas no produjeron semillas. Las plantas tratadas con vermiabono formaron menos raíz respecto a la biomasa total en comparación con el tratamiento testigo, por lo cual se concluye que la aplicación de compost de lombriz promueve el desarrollo de A. americana hasta formar semillas.

  11. Silica-shell encapsulation and adhesion of VO2 nanowires to glass substrates: integrating solution-derived VO2 nanowires within thermally responsive coatings

    Science.gov (United States)

    Pelcher, Kate E.; Crawley, Matthew R.; Banerjee, Sarbajit

    2014-09-01

    The binary vanadium oxide VO2 undergoes a reversible insulatormetal phase transition in response to increasing temperature accompanied by an orders of magnitude alteration of optical transmittance; the low-temperature monoclinic phase of VO2 is infrared-transmissive, whereas the high-temperature rutile phase is infrared-reflective. This remarkable property portends applications in thermally responsive spectral mirrors that can modulate infrared transmittance as a function of temperature. Using a modified Stber process, we demonstrate the constitution of conformal SiO2 shells around the VO2 nanowires. The SiO2 shells enhance the robustness of the VO2 nanowires towards thermal oxidation; the thickness of the shells is observed to depend on the reaction time. Notably, the deposition of conformal shells does not deleteriously impact the metalinsulator transitions of the VO2 nanowire cores. A modification of this approach allows for the VO2 nanowires to be embedded within a SiO2 matrix bonded to glass. The applied coatings are strongly adhered to glass as evaluated using standardized ASTM methods. The coatings exhibit promising thermochromic response and attenuate transmission of near-infrared radiation with increasing temperature.

  12. 'Cation-cation' complexes of pentavalent actinides; complexes formed by NpO+2 or VO+2 with VO2+ in aqueous perchlorate solutions

    International Nuclear Information System (INIS)

    Dioxoneptunium(V) and dioxovanadium(V) ions were found to react with the oxovanadium(IV) ion in acid aqueous perchlorate solutions leading to the formation of the 'cation-cation' complexes NpVO33+ and V2O33+. The stability constants of formation for the NpVO33+ and V2O33+ complexes were found, by near IR spectrophotometry, to be anti K/GAMMA=(0.69 +- 0.12) and (0.31 +- 0.03) M-1 respectively for values of ClO4- concentration of 4.1 to 4.2 M and for values of the ionic strength ? between 6.1 and 6.2. Raman spectrometry was used to study the competition involving the VO2+ and NpO2+ ions, between the formation reactions of the complex, NpVO33+, and of the dimer, Np2O42+. For the NpVO33+ complex, the symmetrical vibration of the linear O=Np(V)=O group was found to occur at 775 cm-1 and a peak corresponding to an Nb-O-V oxygen bridge was not observed. Since a V-O-V oxygen bridge probably exists in the V2O33+ complex, and since Raman spectral evidence for a Np-O-V bridge was not observed, it was concluded that NpVO33+ and V2O33+ have different structures. (orig.)

  13. Microstructures and thermochromic properties of tungsten doped vanadium oxide film prepared by using VO{sub X}-W-VO{sub X} sandwich structure

    Energy Technology Data Exchange (ETDEWEB)

    Luo Zhenfei, E-mail: zhfluo@yahoo.com.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Wu Zhiming, E-mail: zmwu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Xu Xiangdong; Du Mingjun; Wang Tao; Jiang Yadong [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

    2011-05-25

    Tungsten doped vanadium oxide (VO{sub X}) thin films were prepared by oxygen annealing VO{sub X}-W-VO{sub X} sandwich layers. X-ray photoelectron spectroscopy, X-ray diffraction and field emission scanning electron microscope were employed to characterize the compositions, crystal structures and surface morphologies, respectively. It was demonstrated that sandwich structure suppressed the crystallization of VO{sub X}, and that V{sup 5+} was reduced by diffused W atom to V{sup 4+}. The results of surface morphologies indicated that the grain arrangement of W doped vanadium dioxide film exhibited some regular patterns compared with the random grain distribution of undoped film. Electrical measurements showed that the square resistance of V{sub 2}O{sub 5} film and semiconductor-metal transition temperature of VO{sub 2}-V{sub 2}O{sub 5} film decreased obviously after W doping. In addition, thermal hysteresis loop was observed in W doped V{sub 2}O{sub 5} film with thick W middle layer. The investigation of optical properties indicated that the optical band gap of W doped V{sub 2}O{sub 5} film decreased with the increase of thickness of W middle layer, and the optical switching performance in the near-infrared range of VO{sub 2}-V{sub 2}O{sub 5} slightly weakened after W doping.

  14. Self-Assembly and Horizontal Orientation Growth of VO2 Nanowires

    Science.gov (United States)

    Cheng, Chun; Guo, Hua; Amini, Abbas; Liu, Kai; Fu, Deyi; Zou, Jian; Song, Haisheng

    2014-06-01

    Single-crystalline vanadium dioxide (VO2) nanostructures have attracted an intense research interest recently because of their unique single-domain metal-insulator phase transition property. Synthesis of these nanostructures in the past was limited in density, alignment, or single-crystallinity. The assembly of VO2 nanowires (NWs) is desirable for a ``bottom-up'' approach to the engineering of intricate structures using nanoscale building blocks. Here, we report the successful synthesis of horizontally aligned VO2 NWs with a dense growth mode in the [1-100]quartz direction of a polished x-cut quartz surface using a simple vapor transport method. Our strategy of controlled growth of VO2 NWs promisingly paves the way for designing novel metal-insulator transition devices based on VO2 NWs.

  15. Selective growth of single phase VO{sub 2}(A, B, and M) polymorph thin films

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Amar; Saha, Surajit [Department of Physics, National University of Singapore, Singapore 117542 (Singapore); NUSNNI-NanoCore, National University of Singapore, Singapore 117576 (Singapore); Rotella, Helene [NUSNNI-NanoCore, National University of Singapore, Singapore 117576 (Singapore); Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603 (Singapore); Pal, Banabir [Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012 (India); Kalon, Gopinadhan; Mathew, Sinu; Motapothula, Mallikarjuna; Dykas, Michal [NUSNNI-NanoCore, National University of Singapore, Singapore 117576 (Singapore); Yang, Ping [Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603 (Singapore); Okunishi, Eiji [Electron Optics Division, JEOL Ltd., Tokyo 196-8558 (Japan); Sarma, D. D. [Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012 (India); Council of Scientific and Industrial Research-Network of Institutes for Solar Energy (CSIR-NISE), New Delhi 110001 (India); Venkatesan, T., E-mail: venky@nus.edu.sg [Department of Physics, National University of Singapore, Singapore 117542 (Singapore); NUSNNI-NanoCore, National University of Singapore, Singapore 117576 (Singapore); Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603 (Singapore)

    2015-02-01

    We demonstrate the growth of high quality single phase films of VO{sub 2}(A, B, and M) on SrTiO{sub 3} substrate by controlling the vanadium arrival rate (laser frequency) and oxidation of the V atoms. A phase diagram has been developed (oxygen pressure versus laser frequency) for various phases of VO{sub 2} and their electronic properties are investigated. VO{sub 2}(A) phase is insulating VO{sub 2}(B) phase is semi-metallic, and VO{sub 2}(M) phase exhibits a metal-insulator transition, corroborated by photo-electron spectroscopic studies. The ability to control the growth of various polymorphs opens up the possibility for novel (hetero)structures promising new device functionalities.

  16. Theoretical characterization of vanadyl and VO3+ cations in gas phase

    Science.gov (United States)

    Almenia, S.; Mogren Al Mogren, M.; Ben Abdallah, D.; Linguerri, R.; Hochlaf, M.

    2016-02-01

    We investigate VO2+ and VO3+ ions theoretically. The electronic computations are performed using multi reference configuration interaction approaches in conjunction with the aug-cc-pV5Z basis set. VO2+ potential possesses a Morse-like shape instead of the common volcanic shape since both the charge retaining (V2+ + O) and charge separating (V+ + O+) dissociation channels are almost coinciding in energy. Its intense blue color is due to the A2?-X2? transition. We predict VO3+ as metastable. For bound states, we derived a set of accurate spectroscopic parameters. We estimate the adiabatic double and triple ionization energies of VO to be 22.5 eV and 50.9 eV.

  17. Voltage switching of a VO2 memory metasurface using ionic gel

    International Nuclear Information System (INIS)

    We demonstrate an electrolyte-based voltage tunable vanadium dioxide (VO2) memory metasurface. Large spatial scale, low voltage, non-volatile switching of terahertz (THz) metasurface resonances is achieved through voltage application using an ionic gel to drive the insulator-to-metal transition in an underlying VO2 layer. Positive and negative voltage application can selectively tune the metasurface resonance into the off or on state by pushing the VO2 into a more conductive or insulating regime respectively. Compared to graphene based control devices, the relatively long saturation time of resonance modification in VO2 based devices suggests that this voltage-induced switching originates primarily from electrochemical effects related to oxygen migration across the electrolyteVO2 interface.

  18. Voltage switching of a VO{sub 2} memory metasurface using ionic gel

    Energy Technology Data Exchange (ETDEWEB)

    Goldflam, M. D.; Liu, M. K.; Chapler, B. C.; Stinson, H. T.; Sternbach, A. J.; McLeod, A. S.; Basov, D. N., E-mail: dbasov@physics.ucsd.edu [Department of Physics, The University of California at San Diego, La Jolla, California 92093 (United States); Zhang, J. D.; Geng, K. [Department of Physics, Boston University, Boston, Massachusetts 02215 (United States); Royal, M.; Jokerst, N. M.; Smith, D. R. [Center for Metamaterials and Integrated Plasmonics, Pratt School of Engineering, Duke University, Durham, North Carolina 27708 (United States); Kim, Bong-Jun [Metal-Insulator Transition Creative Research Center, ETRI, Daejeon 305-350 (Korea, Republic of); Averitt, R. D. [Department of Physics, The University of California at San Diego, La Jolla, California 92093 (United States); Department of Physics, Boston University, Boston, Massachusetts 02215 (United States); Kim, H-T. [Metal-Insulator Transition Creative Research Center, ETRI, Daejeon 305-350 (Korea, Republic of); School of Advanced Device Technology, University of Science and Technology, Daejeon 305-333 (Korea, Republic of)

    2014-07-28

    We demonstrate an electrolyte-based voltage tunable vanadium dioxide (VO{sub 2}) memory metasurface. Large spatial scale, low voltage, non-volatile switching of terahertz (THz) metasurface resonances is achieved through voltage application using an ionic gel to drive the insulator-to-metal transition in an underlying VO{sub 2} layer. Positive and negative voltage application can selectively tune the metasurface resonance into the off or on state by pushing the VO{sub 2} into a more conductive or insulating regime respectively. Compared to graphene based control devices, the relatively long saturation time of resonance modification in VO{sub 2} based devices suggests that this voltage-induced switching originates primarily from electrochemical effects related to oxygen migration across the electrolyteVO{sub 2} interface.

  19. Synthesis, structure, luminescence properties, quantum chemistry and cytotoxic effects of two vanadium(IV) complexes with polypyrazolylborates, HB(pz)3VO(acac) and HB(3,5-Me2pz)3VO(acac)CH3CN (pz=pyrazole)

    International Nuclear Information System (INIS)

    The reaction of VO(acac)2 (acac = acetylacetonate) with NaHB(pz)3 (pz=pyrazole) or NaHB(3,5-Me2pz)3 in methanol gave vanadium(IV) complexes HB(pz)3VO(acac) (1) or HB(3,5-Me2pz)3VO(acac)CH3CN (2), respectively. The complexes 1 and 2 were characterized by elemental analysis, IR, UV-vis, 1H NMR and X-ray diffraction crystallography methods. Complex 1 crystallizes in space group P21/c, a=7.641(2), b=17.008(4), c=13.362(2) A; ?=92.092(17) deg, V=1735.5(7) A3, Z=4. Complex 2 crystallizes in space group P21/c, a=17.410(13), b=8.076(16), c=19.300(13) A; ?=101.75(5) deg, V=2657(6) A3, Z=4. X-ray structure analyses have shown that the complexes 1 and 2 are monomeric with a similar coordination environment of the vanadium atom. Luminescence properties and cytotoxic effects of the complexes are discussed. On CBRH-7919 cells, the complexes 1 and 2 caused a slight stimulation of growth at low doses (1-10 ?M) and a significant cytotoxic effect at higher doses (100-1000 ?M). The electronic structure and the bonding characters of the two complexes were analyzed with ab initio calculations

  20. VO{sub 2} (A): Reinvestigation of crystal structure, phase transition and crystal growth mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Rao Popuri, Srinivasa [ICMCB, CNRS, UPR 9048, F-33608 Pessac (France); University of Bordeaux, ICMCB, UPR 9048, F-33608 Pessac (France); National Institute for Research and Development in Electrochemistry and Condensed Matter, Timisoara, Plautius Andronescu Str. No. 1, 300224 Timisoara (Romania); Artemenko, Alla [ICMCB, CNRS, UPR 9048, F-33608 Pessac (France); University of Bordeaux, ICMCB, UPR 9048, F-33608 Pessac (France); Labrugere, Christine [CeCaMA, University of Bordeaux 1, ICMCB, 87 Avenue du Dr. A. Schweitzer, F-33608 Pessac (France); Miclau, Marinela [National Institute for Research and Development in Electrochemistry and Condensed Matter, Timisoara, Plautius Andronescu Str. No. 1, 300224 Timisoara (Romania); Villesuzanne, Antoine [ICMCB, CNRS, UPR 9048, F-33608 Pessac (France); University of Bordeaux, ICMCB, UPR 9048, F-33608 Pessac (France); Pollet, Michal, E-mail: pollet@icmcb-bordeaux.cnrs.fr [ICMCB, CNRS, UPR 9048, F-33608 Pessac (France); University of Bordeaux, ICMCB, UPR 9048, F-33608 Pessac (France)

    2014-05-01

    Well crystallized VO{sub 2} (A) microrods were grown via a single step hydrothermal reaction in the presence of V{sub 2}O{sub 5} and oxalic acid. With the advantage of high crystalline samples, we propose P4/ncc as an appropriate space group at room temperature. From morphological studies, we found that the oriented attachment and layer by layer growth mechanisms are responsible for the formation of VO{sub 2} (A) micro rods. The structural and electronic transitions in VO{sub 2} (A) are strongly first order in nature, and a marked difference between the structural transition temperatures and electronic transitions temperature was evidenced. The reversible intra- (LTP-A to HTP-A) and irreversible inter- (HTP-A to VO{sub 2} (M1)) structural phase transformations were studied by in-situ powder X-ray diffraction. Attempts to increase the size of the VO{sub 2} (A) microrods are presented and the possible formation steps for the flower-like morphologies of VO{sub 2} (M1) are described. - Graphical abstract: Using a single step and template free hydrothermal synthesis, well crystallized VO{sub 2} (A) microrods were prepared and the P4/ncc space group was assigned to the room temperature crystal structure. Reversible and irreversible phase transitions among different VO{sub 2} polymorphs were identified and their progressive nature was highlighted. Attempts to increase the microrods size, involving layer by layer formation mechanisms, are presented. - Highlights: Highly crystallized VO{sub 2} (A) microrods were grown via a single step hydrothermal process. The P4/ncc space group was determined for VO{sub 2} (A) at room temperature. The electronic structure and progressive nature of the structural phase transition were investigated. A weak coupling between structural and electronic phase transitions was identified. Different crystallite morphologies were discussed in relation with growth mechanisms.

  1. Synthesis and visible-light photocatalytic activity of NdVO{sub 4} nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Xu Jing [Department of Applied Physics, Chongqing University, Chongqing 400044 (China); Chongqing University of Science and Technology, Chongqing 401331 (China); Hu Chenguo, E-mail: hucg@cqu.edu.cn [Department of Applied Physics, Chongqing University, Chongqing 400044 (China); Liu Gaobin [Department of Applied Physics, Chongqing University, Chongqing 400044 (China); Liu Hong; Du Guojun [State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Zhang Yan [Department of Applied Physics, Chongqing University, Chongqing 400044 (China)

    2011-07-28

    Graphical abstract: NdVO{sub 4} nanowires are synthesized by a simple composite molten salt method. The effective light absorption and photodegradation are found. Highlights: > We report the fabrication, characterization and photocatalytic activity of NdVO{sub 4} nanowires synthesized by the composite molten salt method. > The NdVO{sub 4} nanowires show effective light absorption and high catalytic degradation activity to Rhodamine B. > The electron density states of the NdVO{sub 4} were calculated with the Vienna ab initio simulation package, which explains the light absorption and photodegradation properties. - Abstract: NdVO{sub 4} nanowires are synthesized by a simple composite molten salt method. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrum, energy dispersive spectrometry and UV-vis spectrum are used to characterize the structure, morphology and composition of the sample. The results show that the product is of tetragonal phase NdVO{sub 4} nanowires which are connected together in bases, rooted in one center, with typical diameters of 100 nm and lengths up to 3 {mu}m. The UV-vis spectrum shows that NdVO{sub 4} nanowires have four strong absorption peaks from the UV to near infrared region. The photocatalytic degradation of Rhodamine B (RhB) and methyl orange under visible light irradiation using the NdVO{sub 4} nanowires are also investigated. Excellent catalytic degradation activity of RhB observed suggests possible applications for organic pollutant treatment under visible light irradiation. The electron density states of the NdVO{sub 4} were calculated with the Vienna ab initio simulation package. The results of these simulations were used to form a description of the observed light absorption and photodegradation properties of NdVO{sub 4} nanowires.

  2. Prepaid and Postpaid VoIP Service Enhancements and Hybrid Network Performance Measurement

    Directory of Open Access Journals (Sweden)

    Mohd Nazri Ismail

    2006-01-01

    Full Text Available This study focuses on prepaid and postpaid VoIP technology service enhancement. The aims are to i merge wireless technology in rural areas with wired technologies and services in urban areas. It intends to investigate the minimum requirement needs by wireless and wired technology in using of telco connectivity. It is also to define which technology will achieve a low operating cost and good performance. In addition, the most apparent benefit of implementing prepaid/postpaid VoIP network in rural areas is that to achieve a robust fault tolerance and load-balancing voice traffic between urban and rural areas. ii Merging of WAP and VoIP network to provide Information-on-Demand (IoD services to prepaid and postpaid VoIP users. It is to provide value added services for prepaid and postpaid VoIP users. WAP and other similar technologies will continue to play an important role in the development of Information-on-Demand (IoD services in future. In addition, the most apparent benefit of implementing WAP technology with prepaid/postpaid VoIP network architecture is that to achieve WAP enabled mobile to access this facility during travelling, meeting, seminar and conference. Integration of WAP technology with prepaid/postpaid VoIP network architecture can achieve efficiency end-to-end information services between service providers (ISPs/ITSPs and WAP mobile phone users. Therefore, prepaid and postpaid VoIP service enhancement can improve and obtain high efficiency network, technical, business and customer-care aspects in contributing the robust prepaid/postpaid VoIP network architecture for prepaid/postpaid VoIP users.

  3. Synthesis and visible-light photocatalytic activity of NdVO4 nanowires

    International Nuclear Information System (INIS)

    Graphical abstract: NdVO4 nanowires are synthesized by a simple composite molten salt method. The effective light absorption and photodegradation are found. Highlights: ? We report the fabrication, characterization and photocatalytic activity of NdVO4 nanowires synthesized by the composite molten salt method. ? The NdVO4 nanowires show effective light absorption and high catalytic degradation activity to Rhodamine B. ? The electron density states of the NdVO4 were calculated with the Vienna ab initio simulation package, which explains the light absorption and photodegradation properties. - Abstract: NdVO4 nanowires are synthesized by a simple composite molten salt method. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrum, energy dispersive spectrometry and UV-vis spectrum are used to characterize the structure, morphology and composition of the sample. The results show that the product is of tetragonal phase NdVO4 nanowires which are connected together in bases, rooted in one center, with typical diameters of 100 nm and lengths up to 3 ?m. The UV-vis spectrum shows that NdVO4 nanowires have four strong absorption peaks from the UV to near infrared region. The photocatalytic degradation of Rhodamine B (RhB) and methyl orange under visible light irradiation using the NdVO4 nanowires are also investigated. Excellent catalytic degradation activity of RhB observed suggests possible applications for organic pollutant treatment under visible light irradiation. The electron density states of the NdVO4 were calculated with the Vienna ab initio simulation package. The results of these simulations were used to form a description of the observed light absorption and photodegradation properties of NdVO4 nanowires.

  4. Caracterizacin de la biomasa inactiva de Aspergillus niger O-5 como sorbente de Pb (II

    Directory of Open Access Journals (Sweden)

    Yusleydi Enamorado Horrutiner

    2011-01-01

    Full Text Available The inactive biomass of fungus Aspergillus niger O-5 obtained in Cuba was characterized as sorbent of Pb2+ by several structural analysis and others techniques. In addition, the biomass was studied for the separation / preconcentration of Pb2+ from aqueous solution. The maximum biosorption capacity was obtained for the contact time of 30 min and pH 5. The kinetic of sorption process occurred according to the model of Ho. The Freundlich or Langmuir models suitably described the experimental adsorption isotherms. The biomass can be used as sorbent for Pb2+ with a maximum capacity of 4.7 - 6.2 mg g-1. The pretreatment with NaOH solution improved its sorption capacity.

  5. Abundancia y biomasa de macroinvertebrados edficos en la temporada lluviosa, en tres usos de la tierra, en los Andes colombianos

    Directory of Open Access Journals (Sweden)

    Pardo Luis C

    2006-03-01

    Full Text Available COMPENDIO los usos evaluados fueron pastizal, cafetal y bosque secundario (Vereda Villa del Rosario, Aprox. 3 33' 16? Latitud Norte y 76 36' 01? Longitud Oeste, altitud 1.500 a 1.820m., precipitacin 960 a 1.050 mm/ao, 19.8 a 21.2 C con la metodologa TSBF. Se implementaron tres monolitos por uso y cada uno se subdividi en cuatro estratos (hojarasca, 0-10 cm, 10-20 cm, y 20-30 cm, las variables densidad y biomasa por parcela y estrato se examinaron a travs de ANOVAS y Post-Anovas. En abundancia la supremaca fue de hormigas (25584 ejemplares, miripodos (4808 ejemplares y lombrices (1984 ejemplares, la diferencia significativa la marcaron los miripodos (F=4.84, P=0.014 asociados con bosque y cafetal con sombro. En biomasa los grupos ms importantes fueron miripodos (701.05 g m-2, 58.71%, lombrices (90.64 g m-2; 7.59%, chisas (27.07 g m-2; 2.26% hormigas (20.90 g m-2; 1.75% y araas (15.71 g m-2 ; 1.31%, con diferencias significativas en hormigas (F=4.17, P=0.024 y araas (F=3.43, P=0.4024; Tambin hubo diferencias estadsticas significativas en la densidad y biomasa de macroinvertebrados y los estratos de los monolitos, los resultados indican que estos organismos expresan en su poblacin y biomasa respuestas ambientales asociadas ms con la estructura del agroecosistema que con la variacin qumica, fsica o microbiolgica del hbitat; se recomienda discriminar taxonmicamente los grupos funcionales y ampliar los muestreos a la temporada seca. Palabras clave: uso del suelo, macroinvertebrados edficos, densidad, abundancia, agroecosistemas, Andes colombianos. ABSTRACT Abundance and biomass of soil macroinvertabrates during the rainy season in three land use systems in the Colombian Andes. Using the TSBF methodology, three land use systems—pastures, coffee plantation, and secondary forest— were evaluated in the rural community of Villa del Rosario, located in the municipality of Cali, Valle del Cauca, Colombia . This community is located at approximately 3 33' 16 N and 76 36' 01 W, with an altitude of 1.500-1.820 m above sea level, an annual precipitation of 960-1.050 mm, and temperatures ranging from 19.8 to 21.2 C. Three monoliths were used per land use system, each one subdivided into four strata (fallen leaves and 0-10 cm, 10-20 cm, and 20-30 cm in depth. The variables for density and biomass per plot and stratum were submitted to ANOVA and post-ANOVA comparison. Among macroinvertebrates found, ants outnumbered the others by far with 25.584 individuals, followed by myriapods with 4808 individuals, and earthworms with 1984. A significant difference was found in the case of myriapods (F=4.84, P=0.014 in association with forest and coffee plantation under shade. In terms of biomass, the most important groups found were myriapods (701.05 g m-2, 58.71%, earthworms (90.64 g m-2, 7.59%, grubs (27.07 g m-2, 2.26%, ants (20.90 g m-2, 1.75%, and spiders (15.71 g m-2, 1.31%. Significant differences were found in the case of ants (F=4.17, P=0.024 and spiders (F=3.43, P=0.4024. Significant statistical differences were also found for density and biomass of macroinvertebrates and monolith strata. Results indicated that the environmental response of these organisms in terms of population and biomass is more associated to agroecosystem structure than to chemical, physical, or microbiological variation of the habitat. Functional groups should be taxonomically differentiated and samplings should be extended to the dry season. Key words: land use, soil macroinvertebrates, density, agroecosystems, Colombian Andes, biomass.

  6. A cost-effective method to fabricate VO2 (M) nanoparticles and films with excellent thermochromic properties

    International Nuclear Information System (INIS)

    Highlights: • Via solvent–thermal and pyrolysis method, VO2 (M) powder was synthesized in air. • Aiding by grinding, VO2 (M) nanoparticles with the size of 22 nm were obtained. • The VO2 films show great thermochromic properties with Tlum = 62.1% and ΔTsol = 12.4%. • The haze is down to 1.9%, which is superior with films prepared by other methods. - Abstract: In this paper, high crystallinity and pure phase VO2 (M) powder is synthesized by a novel and facile method. Aiding by additional manual grinding and etching process, 22 nm high-quality VO2 (M) nanoparticles can be obtained. The structure and properties of the VO2 (M) particles were characterized by X-ray diffraction analysis, transmission electron microscopy, differential scanning calorimetry and UV–vis–NIR spectrophotometer. After mixing VO2 (M) nanoparticles with transparent polymer, thin films prepared by grinded VO2 nanoparticles show excellent thermochromic properties. The solar modulation ability is up to 12.4% with luminous transmittance of 62.7%. Moreover, The haze of films prepared by grinded VO2 (M) nanoparticles is down to 1.9%, which is far less than that of films prepared by original VO2 (Haze = 8.5%) and etched VO2 particles (Haze = 4.6%). Dramatical improvement of thermochromic property and definition indicate that it is a promising method to prepare large-scale VO2 nanoparticles and cost-effective smart window

  7. Biosorption of Pb (II) by Agave tequilana Weber (agave azul) biomass / Biosorpcin de Pb (II) por biomasa de Agave tequilana Weber (agave azul)

    Scientific Electronic Library Online (English)

    J, Romero-Gonzlez; F, Parra-Vargas; I, Cano-Rodrguez; E, Rodrguez; J, Ros-Arana; R, Fuentes-Hernndez; J, Ramrez-Flores.

    2007-12-01

    Full Text Available En este estudio, la biomasa producida de los residuos industriales y el desecho agrcola del Agave tequilana Weber (Agave azul) generados en la produccin de tequila, demostr un alto potencial para la remocin de Pb (II) de soluciones acuosas. La capacidad de biosorcin de la biomasa de las hojas d [...] e Agave azul fue evaluada en experimentos en lote. Estos experimentos incluyeron perfil de pH, dependencia del tiempo y la determinacin de la capacidad de adsorcin. Los experimentos de dependencia del tiempo indicaron que la adsorcin de los iones de Pb(II) por la biomasa de Agave azul fue dependiente del tiempo. Las isotermas de Freundlich y Langmuir fueron usadas para describir la biosorcin del Pb (II) sobre la biomasa de las hojas del Agave azul a 298 K y un pH de 5.0. El coeficiente de correlacin para la isoterma de Freundlich fue ms alto que el respectivo coeficiente para la isoterma de Langmuir, indicando que solo el modelo de Freundlich describe los datos obtenidos. La mxima capacidad (K F) fue 105.52 10-2 moles/g para Pb (II). La capacidad de adsorcin mostrada por la biomasa del Agave azul fue ms alta que el valor promedio de los valores reportados en la literatura. Abstract in english In this study, the biomass produced from the industrial residues and agricultural waste of Agave tequilana Weber (Agave azul) generated in the production of tequila, demonstrated a high potential for Pb (II) removal from aqueous solution. The biosorption capacity of Agave azul leaves biomass was eva [...] luated in batch experiments. These experiments included pH profile, time dependence, and the determination of adsorption capacity. Time profile experiments indicated that the adsorption of Pb ions by Agave azul biomass was time-dependent. Freundlich and Langmuir isotherms were used to describe the biosorption of Pb (II) onto the Agave azul leaves biomass at 298 K and pH 5.0. The correlation coefficient for the Freundlich isotherm was much higher than the coefficient for the Langmuir isotherm, indicating that only the Freundlich models fits the data. The maximum capacity (K F) was 105.52 10-2 mole/g for Pb (II). The adsorption capacity showed by Agave azul biomass was higher than the average values reported in the literature.

  8. Zircon to monazite phase transition in CeVO4

    CERN Document Server

    Panchal, V; Santamaria-Perez, D; Errandonea, D; Manjon, F J; Rodriguez-Hernandez, P; Munoz, A; Achary, S N; Tyagi, A K

    2011-01-01

    X-ray diffraction and Raman-scattering measurements on cerium vanadate have been performed up to 12 and 16 GPa, respectively. Experiments reveal that at 5.3 GPa the onset of a pressure-induced irreversible phase transition from the zircon to the monazite structure. Beyond this pressure, diffraction peaks and Raman-active modes of the monazite phase are measured. The zircon to monazite transition in CeVO4 is distinctive among the other rare-earth orthovanadates. We also observed softening of external translational Eg and internal B2g bending modes. We attributed it to mechanical instabilities of zircon phase against the pressure-induced distortion. We additionally report lattice-dynamical and total-energy calculations which are in agreement with the experimental results. Finally, the effect of non-hydrostatic stresses on the structural sequence is studied and the equations of state of different phases are reported.

  9. A structured approach to VO reconfigurations through Policies

    CERN Document Server

    Reiff-Marganiec, Stephan

    2012-01-01

    One of the strength of Virtual Organisations is their ability to dynamically and rapidly adapt in response to changing environmental conditions. Dynamic adaptability has been studied in other system areas as well and system management through policies has crystallized itself as a very prominent solution in system and network administration. However, these areas are often concerned with very low-level technical aspects. Previous work on the APPEL policy language has been aimed at dynamically adapting system behaviour to satisfy end-user demands and - as part of STPOWLA - APPEL was used to adapt workflow instances at runtime. In this paper we explore how the ideas of APPEL and STPOWLA can be extended from workflows to the wider scope of Virtual Organisations. We will use a Travel Booking VO as example.

  10. Orbital-assisted metal-insulator transition in VO$_{2}$

    CERN Document Server

    Haverkort, M W; Tanaka, A; Reichelt, W; Streltsov, S V; Korotin, M A; Anisimov, V I; Hsieh, H H; Lin, H J; Chen, C T; Khomskii, D I; Tjeng, L H

    2005-01-01

    We found direct experimental evidence for an orbital switching in the V 3d states across the metal-insulator transition in VO$_{2}$. We have used soft-x-ray absorption spectroscopy at the V $L_{2,3}$ edges as a sensitive local probe, and have determined quantitatively the orbital polarizations. These results strongly suggest that, in going from the metallic to the insulating state, the orbital occupation changes in a manner that charge fluctuations and effective band widths are reduced, that the system becomes more 1-dimensional and more susceptible to a Peierls-like transition, and that the required massive orbital switching can only be made if the system is close to a Mott insulating regime.

  11. Active terahertz nanoantennas based on VO2 phase transition.

    Science.gov (United States)

    Seo, Minah; Kyoung, Jisoo; Park, Hyeongryeol; Koo, Sukmo; Kim, Hyun-sun; Bernien, Hannes; Kim, Bong Jun; Choe, Jong Ho; Ahn, Yeong Hwan; Kim, Hyun-Tak; Park, Namkyoo; Park, Q-Han; Ahn, Kwangjun; Kim, Dai-sik

    2010-06-01

    Unusual performances of metamaterials such as negative index of refraction, memory effect, and cloaking originate from the resonance features of the metallic composite atom(1-6). Indeed, control of metamaterial properties by changing dielectric environments of thin films below the metallic resonators has been demonstrated(7-11). However, the dynamic control ranges are still limited to less than a factor of 10,(7-11) with the applicable bandwidth defined by the sharp resonance features. Here, we present ultra-broad-band metamaterial thin film with colossal dynamic control range, fulfilling present day research demands. Hybridized with thin VO(2) (vanadium dioxide) (12-18) films, nanoresonator supercell arrays designed for one decade of spectral width in terahertz frequency region show an unprecedented extinction ratio of over 10000 when the underlying thin film experiences a phase transition. Our nanoresonator approach realizes the full potential of the thin film technology for long wavelength applications. PMID:20469898

  12. Effects of training on muscle O2 transport at VO2max

    Science.gov (United States)

    Roca, J.; Agusti, A. G.; Alonso, A.; Poole, D. C.; Viegas, C.; Barbera, J. A.; Rodriguez-Roisin, R.; Ferrer, A.; Wagner, P. D.

    1992-01-01

    To quantify the relative contributions of convective and peripheral diffusive components of O2 transport to the increase in leg O2 uptake (VO2leg) at maximum O2 uptake (VO2max) after 9 wk of endurance training, 12 sedentary subjects (age 21.8 +/- 3.4 yr, VO2max 36.9 +/- 5.9 ml.min-1.kg-1) were studied. VO2max, leg blood flow (Qleg), and arterial and femoral venous PO2, and thus VO2leg, were measured while the subjects breathed room air, 15% O2, and 12% O2. The sequence of the three inspirates was balanced. After training, VO2max and VO2leg increased at each inspired O2 concentration [FIO2; mean over the 3 FIO2 values 25.2 +/- 17.8 and 36.5 +/- 33% (SD), respectively]. Before training, VO2leg and mean capillary PO2 were linearly related through the origin during hypoxia but not during room air breathing, suggesting that, at 21% O2, VO2max was not limited by O2 supply. After training, VO2leg and mean capillary PO2 at each FIO2 fell along a straight line with zero intercept, just as in athletes (Roca et al. J. Appl. Physiol. 67: 291-299, 1989). Calculated muscle O2 diffusing capacity (DO2) rose 34% while Qleg increased 19%. The relatively greater rise in DO2 increased the DO2/Qleg, which led to 9.9% greater O2 extraction. By numerical analysis, the increase in Qleg alone (constant DO2) would have raised VO2leg by 35 ml/min (mean), but that of DO2 (constant Qleg) would have increased VO2leg by 85 ml/min, more than twice as much. The sum of these individual effects (120 ml/min) was less (P = 0.013) than the observed rise of 164 ml/min (mean). This synergism (explained by the increase in DO2/Qleg) seems to be an important contribution to increases in VO2max with training.

  13. Forest biomass variation in Southernmost Brazil: the impact of Araucaria trees / Variacin de la biomasa forestal en el sur de Brasil: impacto de los rboles de Araucaria

    Scientific Electronic Library Online (English)

    Milena Fermina, Rosenfield; Alexandre F., Souza.

    2014-03-01

    Full Text Available Una variedad de factores ambientales y biticos determinan el crecimiento de la vegetacin y afectan la acumulacin de biomasa vegetal. Desde la temperatura hasta la composicin de especies, en los ecosistemas forestales el almacenamiento de la biomasa area se ve influenciada por una serie de varia [...] bles, razn por la cual generalmente presenta una alta variabilidad espacial. De acuerdo a esto, el objetivo del estudio es analizar las variables que afectan la biomasa rea (en Ingls, aboveground forest biomass - AGB) en los bosques hmedos subtropicales del sur de Brasil y analizar su distribucin espacial. Para el estudio se utilizaron los datos de un inventario forestal realizado en el estado de Rio Grande del Sur, sur de Brasil. Se evaluaron bosques de hoja ancha (Broadleaf forests) y bosques mixtos de hoja ancha y conferas (Mixed Coniferous-Broadleaf forests). Adems, se tomaron muestras de 38 parcelas de 1 ha y para la estimacin de la biomasa se incluyeron todos los rboles con DAP ?9.5cm. Los valores para la biomasa area se obtuvieron con ecuaciones alomtricas publicadas. Las variables ambientales y biticas (altitud, precipitacin, temperatura, suelo, densidad de los troncos y diversidad de especies) se obtuvieron de la literatura o se han calculado a partir del conjunto de datos. Para el conjunto de datos, el AGB medio fue 195.2Mg/ha. Las estimaciones difieren entre los bosques de hoja ancha y los bosques mixtos de hoja ancha y conferas: el AGB promedio fue menor en los bosques de hoja ancha (AGB BF=118.9Mg/ha) en comparacin con los bosques mixtos (AGB MF=250.3Mg/ha). Hubo una alta variabilidad espacial y local en la base de datos, incluso dentro de los tipos de bosques. Esta condicin es normal en los bosques tropicales y por lo general se atribuye a la presencia de grandes rboles. La regresin mltiple fue influenciada principalmente por la altitud y explic 50.7% de la variacin en AGB. La densidad, diversidad y materia orgnica tambin influyeron en la variacin de biomasa. Los resultados mostraron una relacin positiva entre la biomasa sobre el suelo y la altitud. Por lo tanto, los valores ms altos de AGB se encuentran en altitudes mayores y se someten a temperaturas ms bajas y un clima ms hmedo. Parece que hay una importante contribucin de las conferas Araucaria angustifolia en las parcelas de bosques mixto, ya que tienen una biomasa significativamente mayor que las especies de angiospermas. En Brasil, esta especie en peligro de extincin es parte de un bosque de gran diversidad (Bosque de Araucaria) y tiene el potencial de almacenamiento de la biomasa. Los resultados del presente estudio muestran la variabilidad espacial y local de la biomasa area en los bosques subtropicales, destacan la importancia de estos ecosistemas en el almacenamiento global del carbono, y estimulan la mejora de futuras estimaciones de biomasa. Abstract in english A variety of environmental and biotic factors determine vegetation growth and affect plant biomass accumulation. From temperature to species composition, aboveground biomass storage in forest ecosystems is influenced by a number of variables and usually presents a high spatial variability. With this [...] focus, the aim of the study was to evaluate the variables affecting live aboveground forest biomass (AGB) in Subtropical Moist Forests of Southern Brazil, and to analyze the spatial distribution of biomass estimates. Data from a forest inventory performed in the State of Rio Grande do Sul, Southern Brazil, was used in the present study. Thirty-eight 1-ha plots were sampled and all trees with DBH ?9.5cm were included for biomass estimation. Values for aboveground biomass were obtained using published allometric equations. Environmental and biotic variables (elevation, rainfall, temperature, soils, stem density and species diversity) were obtained from the literature or calculated from the dataset. For the total dataset, mean AGB was 195.2Mg/ha. Estimates differed between Broadleaf and Mixed Co

  14. Variao diurna e resposta da cintica do VO2 de ciclistas durante exerccio muito intenso Diurnal variation and Vo2 kinetic response of cyclists during heavy exercis e

    Directory of Open Access Journals (Sweden)

    Marcos G. Santana

    2008-06-01

    Full Text Available O objetivo do presente estudo foi avaliar a influncia da hora do dia nos parmetros da cintica do consumo de oxignio de ciclistas durante exerccio muito intenso. Nove voluntrios do sexo masculino realizaram exerccios de carga constante s 08:00, 13:00 e 18:00 h, em dias diferentes. Estes exerccios foram realizados duas vezes em cada visita, com um intervalo de 1 h entre eles. A intensidade usada foi de 75%? (75% da diferena entre o VO2 no limiar de lactato e o VO2max. A amplitude do componente primrio do VO2 (2597 273 ml.min-1, 2513 268 ml.min-1 e 2609 370 ml.min-1, a constante de tempo do componente primrio do VO2 (19.3 2.5 s, 18.4 3.0 s e 19.7 3.9 s, o componente lento do VO2 (735 81 ml.min-1, 764 99 ml.min-1 e 680 121 ml.min-1 e o tempo de resposta mdia (51.8 4.2 s, 51.2 4.2 s e 51.4 3.4 s no apresentaram diferenas significativas entre os diferentes horrios do dia (08:00, 13:00 e 18:00 h, assim como os demais parmetros da cintica do VO2. Estes resultados sugerem que a resposta da cintica do VO2 de ciclistas durante exerccio muito intenso (75%? no influenciada pela hora do dia.The objective of the present study was to evaluate the influence of the time of day on the parameters of oxygen uptake kinetics of trained cyclists during high intensity exercise. Nine male volunteers repeated bouts at constant loads at 08:00, 13:00 and 18:00 h on different days. These exercise bouts were performed twice on each occasion, with an interval of 1 h between them. The load intensity used was 75%? (75% of the difference between the VO2 at the lactate threshold and the VO2max. The primary VO2 amplitude (2597 273 ml.min-1, 2513 268 ml.min-1 and 2609 370 ml.min-1, the primary VO2 time constant (19.3 2.5 s, 18.4 3.0 s and 19.7 3.9 s, the VO2 slow component (735 81 ml.min-1, 764 99 ml.min-1 and 680 121 ml.min-1 and the mean response time (51.8 4.2 s, 51.2 4.2 s and 51.4 3.4 s did not present significant differences at the different times (08:00, 13:00 and 18:00 h, neither did the other parameters of the VO2 kinetics. These results suggest that the response of the VO2 kinetics of cyclists exercising at high intensity (75%? is not influenced by the time of day.

  15. STRU?NO VO?ENJE: PODRU?JE RADA PROFESIONALNIH SUPERVIZORA?

    Directory of Open Access Journals (Sweden)

    Louis van Kessel

    2007-01-01

    Full Text Available Stru?no vo?enje je podru?je koje se vrlo dinami?no razvija. Oblici njegove pojavnosti mnogo su raznolikiji od aktivnosti koje se provode u okviru profesionalne supervizije iako ona ima odre?ena obiljeja stru?nog vo?enja. Premda se podrijetlo i razvoj stru?nog vo?enja i supervizije razlikuju, ti su koncepti i njihova primjena me?usobno povezani. Profesionalni supervizori moraju imati jasnu sliku o podru?ju stru?nog vo?enja kako bi mogli redefinirati svoju poziciju u okviru dananje supervizije. Zbog toga moraju prou?avati razvoj stru?nog vo?enja. U ?lanku je prikazano kako se pojam stru?nog vo?enja pojavio u anglosaksonskom govornom podru?ju. ?lanak moe posluiti prakti?arima kao informativni vodi? i kao temelj za daljnja prou?avanja radi usporedbe stru?nog vo?enja i profesionalne supervizije te da bi se moglo to?nije odrediti po ?emu su te dvije aktivnosti razli?ite i sli?ne.

  16. Structure and stability of monazite- and zircon-type LaVO4 under hydrostatic pressure

    Science.gov (United States)

    Cheng, Xuerui; Guo, Dongjie; Feng, Shiquan; Yang, Kun; Wang, Yongqiang; Ren, Yufen; Song, Yang

    2015-11-01

    Pure monazite (m)- and zircon (t)-type LaVO4 and LaVO4:Eu3+ were successfully synthesized by a hydrothermal method. The high pressure behavior of m- and t-LaVO4 nanoparticles has been investigated using Raman scattering techniques at room temperature. Raman measurements reveal a slight change for m-LaVO4 at 11.2 GPa because of an isostructural phase transition. However, striking changes in Raman spectra indicate a pressure-induced irreversible phase transition from the zircon to monazite structure for t-LaVO4 at around 5.9 GPa. The evolution of the luminescence spectra of t-LaVO4:Eu3+ has also been studied during the pressure-induced phase transition. It is observed that pressure has a great influence on the fluorescence intensity and the energy levels, which allows a more in-depth understanding of the nature of the pressure-induced phase transition for t-LaVO4. This result further confirms the conclusion that zircon-type RVO4 compounds with larger rare-earth cations will experience zircon to monazite phase transition.

  17. The VO-Dance web application at the IA2 data center

    Science.gov (United States)

    Molinaro, Marco; Knapic, Cristina; Smareglia, Riccardo

    2012-09-01

    Italian center for Astronomical Archives (IA2, http://ia2.oats.inaf.it) is a national infrastructure project of the Italian National Institute for Astrophysics (Istituto Nazionale di AstroFisica, INAF) that provides services for the astronomical community. Besides data hosting for the Large Binocular Telescope (LBT) Corporation, the Galileo National Telescope (Telescopio Nazionale Galileo, TNG) Consortium and other telescopes and instruments, IA2 offers proprietary and public data access through user portals (both developed and mirrored) and deploys resources complying the Virtual Observatory (VO) standards. Archiving systems and web interfaces are developed to be extremely flexible about adding new instruments from other telescopes. VO resources publishing, along with data access portals, implements the International Virtual Observatory Alliance (IVOA) protocols providing astronomers with new ways of analyzing data. Given the large variety of data flavours and IVOA standards, the need for tools to easily accomplish data ingestion and data publishing arises. This paper describes the VO-Dance tool, that IA2 started developing to address VO resources publishing in a dynamical way from already existent database tables or views. The tool consists in a Java web application, potentially DBMS and platform independent, that stores internally the services' metadata and information, exposes restful endpoints to accept VO queries for these services and dynamically translates calls to these endpoints to SQL queries coherent with the published table or view. In response to the call VO-Dance translates back the database answer in a VO compliant way.

  18. Structural, photophysical and photocatalytic properties of novel Bi2AlVO7

    International Nuclear Information System (INIS)

    Bi2AlVO7 was prepared by solid-state reaction technique for the first time and the structural and photocatalytic properties of Bi2AlVO7 and Bi2InTaO7 were investigated. The results showed that Bi2AlVO7 crystallized in the tetragonal crystal system with space group I4/mmm. In addition, the band gaps of Bi2AlVO7 and Bi2InTaO7 were estimated to be about 2.06 and 2.81 eV. The photocatalytic degradation of aqueous methylene blue (MB) dye with Bi2AlVO7 or Bi2InTaO7 as catalyst was investigated under visible light irradiation. Bi2AlVO7 showed higher photocatalytic activity compared with Bi2InTaO7 for photocatalytic degradation of MB under visible light irradiation. Complete removal of aqueous MB dye was realized after visible light irradiation for 160 min with Bi2AlVO7 as the photocatalyst. The reduction of the total organic carbon (TOC) and the formation of inorganic products, SO42- and NO3- revealed the continuous mineralization of aqueous MB dye during the photocatalytic process. The possible photocatalytic degradation pathway of aqueous MB dye was revealed under visible light irradiation.

  19. Preparation and characterization of fly ash cenospheres supported CuO–BiVO4 heterojunction composite

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Novel CuO–BiVO4/FACs heterojunction composites have been synthesized. • CuO–BiVO4 are loaded on the surface of lightweight hollow microspheres. • The CuO–BiVO4/FACs exhibit enhanced absorption in the visible light region. • The CuO–BiVO4/FACs show efficient photocatalytic activities. • The composites are floatable and can be recovered easily. - Abstract: Novel fly ash cenospheres supported CuO–BiVO4 heterojunction composites (CuO–BiVO4/FACs) were prepared by modified metalorganic decomposition and impregnation methods. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectra (XPS), and UV–vis diffused reflectance spectroscopy (DRS) techniques. The XPS and SEM analyses indicated that Cu was present as CuO dispersed on the surface of BiVO4. The DRS spectra revealed that the composites had improved optical adsorption in the visible light region, and the composites exhibited enhanced photocatalytic activity for methylene blue (MB) degradation under visible light irradiation. It was found that the 5 wt% CuO-loaded composite showed the highest photocatalytic activity for MB dye wastewater treatment. FACs, a by-product generated in coal-firing power plants, were used as a low cost support which favored phase separation after the reaction owing to their low density

  20. Effects of erythrocyte infusion on VO2max at high altitude

    DEFF Research Database (Denmark)

    Young, Jette Feveile; Sawka, M N

    1996-01-01

    This study investigated whether autologous erythrocyte infusion would ameliorate the decrement in maximal O2 uptake (VO2max) experienced by lowlanders when they ascend to high altitude. VO2max was measured in 16 men (treadmill running) at sea level (SL) and on the 1st (HA1) and 9th (HA9) days of high-altitude (4,300 m) residence. After VO2max was measured at SL, subjects were divided into two matched groups (n = 8). Twenty-four hours before ascent to high altitude, the experimental group received a 700-ml infusion of autologous erythrocytes and saline (42% hematocrit), whereas the control group received only saline. The VO2max of erythrocyte-infused [54 +/- 1 (SE) ml.kg-1.min-1] and control subjects (52 +/- 2 ml.kg-1.min-1) did not differ at SL before infusion. The decrement in VO2max on HA1 did not differ between groups, averaging 26% overall, despite higher (P <0.01) arterial hematocrit, hemoglobin concentration, and arterial O2 content in the erythrocyte-infused subjects. By HA9, there were no longer any differences in hematocrit, hemoglobin concentration, or arterial O2 content between groups. No change in VO2max occurred between HA1 and HA9 for either group. Thus, despite increasing arterial O2-carrying capacity, autologous erythrocyte infusion did not ameliorate the decrement in VO2max at 4,300-m altitude.

  1. Specific heat of hole-doped vanadates: Y1?xCaxVO3, Pr1-xCaxVO3 and Nd1?xSrxVO3

    International Nuclear Information System (INIS)

    We have investigated the specific heat of hole-doped vanadium oxides Y1?xCaxVO3 (0 ? x ? 0.11), Pr1?xCaxVO3 (0 ? x ? 0.3) and Nd1?xSrxVO3 (0 ? x ? 0.2) probably for the first time by applying the Modified Rigid ion model (MRIM). The results obtained on temperature dependent (1 K ? T ? 300 K) specific heat are in reasonably good agreement with the experimental data. The impact of lattice distortions on the elastic and thermal properties of the present Mott insulators is portrayed by an atomistic approach. The scope of further improvement in the present model has also been discussed. - Highlights: Specific heat increases with decreasing doping level and increase in temperature. Effect of lattice distortions on bulk modulus and thermal properties is presented. MRIM has successfully predicted the cohesive properties of Ca/Sr-doped RVO3

  2. Preparation of Co-BiVO4 Photocatalyst and Its Application in the Photocatalytic Oxidative Thiophene

    Directory of Open Access Journals (Sweden)

    GAO Xiao-Ming, FU Feng, WU Yu-Fei, ZHANG Li-Ping, LI Wen-Hong

    2012-10-01

    Full Text Available The Co-BiVO4 photocatalyst was prepared by hydrothermal method and characterized by X-ray diffraction, scanning electron microscope, UV-Vis absorption spectroscope, and low-temperature N2 adsorption. The characterized results indicate that highly crystalline monoclinic scheelite structure of Co-BiVO4 is obtained at pH=7 and the Co dopant does not change the crystal phase of BiVO4. The Co-BiVO4 has a significant red-shift in the absorption band in the visible region, and its absorption intensity increases greatly for the doped catalyst compared with pure BiVO4. Low-temperature N2 adsorption result reveals that the pore size of the Cu-BiVO4(pH=7 mostly distributes at 2.67 nm. The desulfurization ability of Co-BiVO4 was researched by photocatalytic oxidation of thiophene in visible light. The results show that the Co-BiVO4 photocatalysts exhibit higher photocatalytic activities for degradation of thiophene under visible light irradiation. When pH value is 7.0 and the hydrothermal synthesize time is 8 h, the photocatalytic activities reach the maximum. Under the conditions of 150 mL/min air flow, 1.0 mg/L catalyst amount, and visible light irradiation for 3 h in 400 W xenon lamp light, the desulfurization rate by Co-BiVO4 at 600 mg/L initial concentration increases to 86%.

  3. Synthesis and photocatalytic performances of BiVO4 by ammonia co-precipitation process

    International Nuclear Information System (INIS)

    This paper reports the preparation and photocatalytic performance of Bismuth vanadate (BiVO4) by a facile and inexpensive approach. An amorphous BiVO4 was first prepared by a co-precipitation process from aqueous solutions of Bi(NO3)3 and NH4VO3 using ammonia. Followed by heating treatment at various temperatures, the amorphous phase converted to crystalline BiVO4 with a structure between monoclinic and tetragonal scheelite. The crystallization of BiVO4 occurred at about 523 K, while the nanocrystalline BiVO4 were formed with a heat-treatment of lower than 673 K. However, when the heat-treatment was carried out at 773 K, the accumulation of nanocrystals to bulk particles was observed. The photocatalytic performances of the materials were investigated by O2 evolution under visible-light, and MB decomposition under solar simulator. The results demonstrated that the crystalline structure is still the vital factor for the activities of both reactions. However, the crystallinity of BiVO4 gives a major influence on the activity of O2 evolution, whereas the surface area, plays an important role for photocatalytic MB decomposition. - Abstract: BiVO4 was prepared by a co-precipitation process using aqueous ammonia solution, followed by heating treatment at various temperatures. The crystalline structure and crystallization process, and their influences on photocatalytic O2 evolution and organic pollutants degradation were investigated. It demonstrated that the crystalline structure is still the vital factor for the activities of both reactions. However, the crystallinity of BiVO4 gives a major influence on the activity of O2 evolution, whereas the surface area, plays an important role for photocatalytic MB decomposition. Display Omitted

  4. Determinants of peak VO2 in heart transplant recipients / Determinantes do pico de VO2 em transplantados cardacos

    Scientific Electronic Library Online (English)

    Vitor Oliveira, Carvalho; Guilherme Veiga, Guimares; Marcelo Luiz, Campos-Vieira; Aparecida Maria, Catai; Vagner, Oliveira-Carvalho; Silvia Moreira, Ayub-Ferreira; Edimar Alcides, Bocchi.

    2015-02-01

    Full Text Available Objetivo: Estabelecer os determinantes do VO2 pico em transplantados de corao. Mtodos: Avaliao do paciente foi realizada em dois dias consecutivos. No primeiro dia, os pacientes realizaram a avaliao da variabilidade da frequncia cardaca seguida de um teste de esforo cardiopulmonar. No seg [...] undo dia, os pacientes realizaram ecocardiografia de repouso. Os transplantados foram elegveis se estivessem em uma condio estvel e sem qualquer evidncia de rejeio diagnosticada por bipsia endomiocrdica. Pacientes com marca-passo, limitaes funcionais no cardiovasculares, tais como osteoartrite e doena pulmonar obstrutiva crnica foram excludos deste estudo. Resultados: Sessenta pacientes (68% do sexo masculino, 48 anos e 64 meses aps o transplante cardaco) foram avaliados. A anlise multivariada selecionou as seguintes variveis: sexo (P=0,001), idade (P=0,049), ndice de Massa Corporal (P=0,005), frequncia cardaca de reserva (P Abstract in english Objective: To establish the determinants of the peak VO2 in heart transplant recipients. Methods: Patient's assessment was performed in two consecutive days. In the first day, patients performed the heart rate variability assessment followed by a cardiopulmonary exercise test. In the second day, pa [...] tients performed a resting echocardiography. Heart transplant recipients were eligible if they were in a stable condition and without any evidence of tissue rejection diagnosed by endomyocardial biopsy. Patients with pacemaker, noncardiovascular functional limitations such as osteoarthritis and chronic obstructive pulmonary disease were excluded from this study. Results: Sixty patients (68% male, 48 years and 64 months following heart transplantation) were assessed. Multivariate analysis selected the following variables: receptor's gender (P=0.001), receptor age (P=0.049), receptor Body Mass Index (P=0.005), heart rate reserve (P

  5. TRANSPORTE DE VOZ (VoIP SOBRE REDES IPv4 e IPv6

    Directory of Open Access Journals (Sweden)

    Fausto Alexander Gamboa

    2012-05-01

    Full Text Available El presente artículo tiene como finalidad evaluar el comportamiento de la VoIP en redes IPv6 y compararlo con IPv4, de igual manera presentar las arquitecturas que la soportan. Con el fin de que los resultados sean los más cercanos a la realidad, el artículo no solo se soporta en simulaciones si no en implementaciones reales. Dentro de las conclusiones más sobresalientes se encontró que la VoIP6 presenta mejor rendimiento ante el Jitter y el retardo que VoIPv4.

  6. Impact of VoIP and QoS on Open and Distance Learning

    OpenAIRE

    Sanjay JASOLA; Saxena, P.C.; Ramesh C. SHARMA

    2006-01-01

    Voice over Internet Protocol (VoIP) is becoming a reality in many organizations. The potential for mobility in voice over wi-fi networks will derive demand for the technology. Wireless VoIP is poised to rival VoIP as an alternative telephony tool. Internet has been used to transport data in the form of packet. In the past, Internet did not support any kind of sophisticated quality of service (QoS) mechanism. Although the type of service (TOS) field in the Internet protocol (IP) header has be...

  7. Surface versus bulk characterization of the electronic inhomogeneity in a VO_{2} film

    OpenAIRE

    Chang, Y. J.; Yang, J.S.; Kim, Y. S.; Kim, D. H.; Noh, T. W.; Kim, D.-W.; Oh, E.; Kahng, B.; Chung, J. -S.

    2007-01-01

    We investigated the inhomogeneous electronic properties at the surface and interior of VO_{2} thin films that exhibit a strong first-order metal-insulator transition (MIT). Using the crystal structural change that accompanies a VO_{2} MIT, we used bulk-sensitive X-ray diffraction (XRD) measurements to estimate the fraction of metallic volume p^{XRD} in our VO_{2} film. The temperature dependence of the p$^{XRD}$ was very closely correlated with the dc conductivity near the M...

  8. Study on the QoE for VoIP Networks

    OpenAIRE

    Weiwei Zhang; Yongyu Chang; Yitong Liu; Atif Hameed; Yuan Tian

    2014-01-01

    In recent years, people are recognizing that the quality in VoIP application should be evaluated according to the QoE (Quality of Experience). The main goal of this paper is to analyze the different factors on the impact of voice quality for VoIP networks. Our contributions are thus threefold: First, we establish a new VoIP simulation platform. The network simulation software is WANem, the voice communication protocol is implemented by Open Phone. This simulation system is more real&rs...

  9. VO2+-hydroxyapatite complexes as models for vanadyl coordination to phosphate in bone

    OpenAIRE

    Dikanov, Sergei A.; Liboiron, Barry D.; Orvig, Chris

    2013-01-01

    We describe a 1D and 2D ESEEM investigation of VO2+ adsorbed on hydroxyapatite (HA) at different concentrations and compare with VO2+-triphosphate (TPH) complexes studied previously in detail, in an effort to provide more insight into the structure of VO2+coordination in bone. Structures of this interaction are important because of the role of bone in the long-term storage of administered vanadium, and the likely role of bone in the steady-state release of vanadium leading to the chronic insu...

  10. Raman study of phonon modes in ErVO4 single crystals

    Science.gov (United States)

    Guedes, I.; Hirano, Y.; Grimsditch, M.; Wakabayashi, N.; Loong, C.-K.; Boatner, L. A.

    2001-08-01

    The phonon modes of a pure ErVO4 crystal were determined at room temperature using Raman scattering methods, and the observed frequencies were assigned according to group theory in terms of the internal modes of the VO43- ions and the external modes of the Er(VO4) lattice. The assignments of the phonon modes match well with the overall phonon systematics of the rare-earth orthovanadate series, and the results presented here reinforce the general trend of bonding strength in the zircon series of RVO4, RAsO4, and RPO4 materials.

  11. VO2max Trainability and High Intensity Interval Training in Humans: A Meta-Analysis

    OpenAIRE

    Bacon, Andrew P.; Carter, Rickey E; Ogle, Eric A.; Joyner, Michael J.

    2013-01-01

    Endurance exercise training studies frequently show modest changes in VO2max with training and very limited responses in some subjects. By contrast, studies using interval training (IT) or combined IT and continuous training (CT) have reported mean increases in VO2max of up to ?1.0 L min?1. This raises questions about the role of exercise intensity and the trainability of VO2max. To address this topic we analyzed IT and IT/CT studies published in English from 19652012. Inclusion criteria w...

  12. Predictability of VO2 max from submaximal cycle ergometer and bench stepping tests.

    OpenAIRE

    Fitchett, M A

    1985-01-01

    The predictability of the maximal oxygen uptake (VO2 max) was studied using progressive and steady state protocols for cycle ergometry and bench stepping. The subjects were 12 healthy men, 23-58 years old. Prediction of VO2 max was made by extrapolation of the heart rate and O2 uptake at several sub-maximal work-loads using the least squares regression technique. The four sub-maximal procedures underestimated the measured VO2 max by between 0.13-0.55 l.min-1. The differences between the measu...

  13. Physical origins of ON-OFF switching in ReRAM via VO based conducting channels

    Science.gov (United States)

    Kamiya, Katsumasa; Yang, Moon Young; Park, Seong-Geon; Magyari-Kpe, Blanka; Nishi, Yoshio; Niwa, Masaaki; Shiraishi, Kenji

    2013-12-01

    We study the ON-OFF switching mechanism of ReRAM via oxygen vacancy (VO) based conducting channels using first-principles calculations. We find cohesion-dispersion transition of VO upon carrier injection and removal is a strong driving force in the ON-OFF switching in binary-oxide-based ReRAMs. The physical origins of the transition is the formation of bonding-like hybridized orbitals of VO defect levels, whose occupation can be controlled by changing system Fermi level by applying a voltage.

  14. Study on Thermochromic VO2 Films Grown on ZnO-Coated Glass Substrates for Smart Windows

    Science.gov (United States)

    Kato, Kazuhiro; Song, Pung Keun; Odaka, Hidehumi; Shigesato, Yuzo

    2003-10-01

    Vanadium dioxide (VO2) is one of the most attractive thermochromic materials, which show large changes in optical and electrical properties at the transition temperature (Tt) close to the atmospheric temperature (approximately 340 K). We already reported for VO2 deposition by rf magnetron sputtering using V2O3 or V2O5 targets that VO2 films thicker than 400 nm showed high thermochromic performance, whereas the VO2 films thinner than 200 nm did not show such performance because of their poor crystallinity and off-stoichiometry. In this study, very thin thermochromic VO2 films with thicknesses of about 50 nm were successfully deposited using highly -preferred oriented ZnO polycrystalline films as a buffer layer between the VO2 film and glass substrate (VO2/ZnO/glass) because of the heteroepitaxial growth of VO2 polycrystalline films. W-doped VO2 films were also deposited on the ZnO-coated glass substrates (ZnO/glass) by cosputtering. It was confirmed that W doping for thin VO2 films deposited on the ZnO/glass can decrease Tt systematically. Such very thin VO2 films should have high potential for application in smart windows.

  15. Vplyv herbicdu Gesagard a fungicdu Fundazol na spolo?enstvo streptomyct vo vysokohorskej pde.

    Czech Academy of Sciences Publication Activity Database

    Seleiov, Z.; Javorekov, S.; Krit?fek, Vclav; Chro?kov, Alica

    2010-01-01

    Ro?. 9, ?. 1 (2010), s. 13-19. ISSN 1336-1120 R&D Projects: GA Mk LC06066 Grant ostatn: SAV(SK) VEGA 1/0404/09; SAV(SK) KEGA 3/6228/08 Institutional research plan: CEZ:AV0Z60660521 Keywords : pesticides * streptomycetes * grassland Subject RIV: EH - Ecology, Behaviour

  16. Biomasa, rendimiento, eficiencia en el uso del agua y de la radiacin solar del agrosistema girasol-frijol

    Directory of Open Access Journals (Sweden)

    Edgar J. Morales-Rosales

    2006-01-01

    Full Text Available El estudio se realiz durante el verano de 2002 Los tratamientos consistieron en la siembra en unicultivo y combinacin de frijol Canario 107, Bayomex (hbito de crecimiento determinado, Michoacn (hbito de crecimiento indeterminado y girasol cv. Victoria. La siembra se realiz el 25 de mayo de 2002 a la densidad de poblacin de 4.2 y 8.3 plantas m-2 de girasol y frijol, respectivamente, en un suelo de textura arcillosa, con un pH de 7.8 y se fertiliz con 100-100-00 de NPK. El diseo experimental fue bloques al azar con cuatro repeticiones. El sistema de siembra no afect la fenologa, el requerimiento trmico y la evapotranspiracin de ambos cultivos. Las unidades calor (UC y la evapotranspiracin (ETc de los cultivos de la siembra a la madurez fisiolgica fueron 1521 UC y 279.6 mm para el cv. Victoria, 658 UC y 201.3 mm para Canario 107, 811 UC y 213.7 mm para Bayomex y 1041 UC y 241.7 mm para Michoacn. El agrosistema combinado de girasol y frijol fue ms eficiente en el uso de los insumos para la produccin agrcola. La combinacin de girasol Victoria y frijol Michoacn mostr la eficiencia en el uso del agua (EUA y eficiencia en el uso de la radiacin (EUR ms alta y, en consecuencia, una mayor produccin de biomasa y rendimiento. El uso equivalente de la tierra (UET para el rendimiento de semilla obtenido con la combinacin de Victoria ms Canario 107, Victoria ms Michoacn y Victoria ms Bayomex fue de 1.6, 1.9 y 3.0, respectivamente, y muestra una ventaja en el rendimiento de los cultivos combinados sobre los unicultivos de 60, 90 y 200%, respectivamente.

  17. PRELIMINARY ANALYSIS OF BIOMASS POTENTIALLY USEFUL FOR PRODUCING BIODIESEL / ANALISIS PRELIMINAR DE BIOMASA POTENCIALMENTE TIL PARA PRODUCIR BIODIESEL

    Scientific Electronic Library Online (English)

    GERARDO, CABRERA CIFUENTES; JUAN CARLOS, BURBANO JARAMILLO; JOS ISIDRO, GARCIA MELO.

    2011-12-01

    Full Text Available Considerando que el biodiesel se est convirtiendo en una solucin viable para algunos problemas energticos y medioambientales, la investigacin de materias primas para su produccin es un tema de creciente inters. Este estudio presenta los resultados de una investigacin dedicada al anlisis prel [...] iminar de varias especies vegetales (biomasa), potencialmente tiles para producir biodiesel. La zona de bioprospeccin es una regin de la costa pacifica colombiana. Las especies promisorias recolectadas fueron sometidas a diferentes pruebas normalizadas ASTM para definir propiedades que faciliten su evaluacin. Algunas de las especies fueron sometidas a un proceso de transesterificacin. Adicionalmente, se realiza una comparacin entre las propiedades termo-fsicas de los biodiesel y las propiedades del diesel comercial. Las pruebas de rendimiento de estos biocombustibles en los motores de encendido por compresin, particularmente la eficiencia, el consumo y la potencia a diferentes RPM del motor, se presentan en este trabajo. Abstract in english Given that biodiesel is emerging as a viable solution for some energy and environmental problems, research on raw materials appropriate for its production is a matter of growing interest. In this study we present the results of research devoted to preliminary analysis on several vegetable (biomass) [...] species potentially useful for producing biodiesel. The bioprospection zone is a region on the Colombian Pacific coast. The candidate species collected underwent different standardized ASTM tests in order for us to define properties that facilitate their evaluation. Some of the species underwent a transesterification process. Comparisons between the thermo-physical properties of the biofuels obtained and the properties of commercial diesel were carried out. Also, performance tests for these biofuels were conducted in compression ignition engines, particularly evaluating efficiency, fuel consumption, and potency at different RPMs.

  18. Caracterizacin de aerosoles por quema de biomasa en el sureste de Mxico / Characterization of biomass burning aerosols over southeast Mexico

    Scientific Electronic Library Online (English)

    Virginia Edith, Corts-Hernndez; Javier, Aparicio.

    2014-02-01

    Full Text Available La caracterizacin de los aerosoles atmosfricos es de gran importancia en los procesos de transferencia radiativa en la atmsfera y el balance de radiacin del sistema climtico. En este trabajo se presentan algunas propiedades fsicas que forman parte de la caracterizacin ptica y radiativa de lo [...] s aerosoles atmosfricos registrados en dos sitios de monitoreo pertenecientes a la red AERONET, ubicados al sureste de Mxico, durante el periodo 2005-2007. La ubicacin de los dos sitios de monitoreo correspondi a la regin de mayor quema de biomasa por incendios forestales durante el ao 2005. La caracterizacin de los aerosoles atmosfricos consider cuatro casos de estudio: 1) 23 de abril de 2005, en Tenosique, Tabasco; 2) 27 de abril de 2005; 3) 8 de mayo de 2006, y 4) 24 de mayo de 2007, en Tuxtla Gutirrez, Chiapas. Los resultados muestran altos valores del espesor ptico del aerosol (? > 1.4), altos valores del coeficiente de ngstrm (? > 0.8), modos finos de acumulacin del aerosol (r Abstract in english Characterization of aerosols is important for the atmospheric radiative process and the radiation budget of the climate system. This study presents some physical properties forming part of the optical and radiative characterization of atmospheric aerosols measured in two monitoring sites from the AE [...] RONET network located in Southeastern Mexico during 2005-2007. The location of both sites corresponded to the region of high biomass burning activity during 2005. Characterization of aerosols considered four study cases: 1) April 23, 2005 in Tenosique, Tabasco, 2) April 27, 2005, 3) May 8, 2006 and 4) May 24, 2007 in Tuxtla Gutierrez, Chiapas. Results show values of high atmospheric optical depth (? > 1.4), fine accumulation mode particles (r

  19. Modelos de biomasa area y foliar en una plantacin de pino de rpido crecimiento en Oaxaca / Above-ground and needle biomass models on a fast-growing pine plantation in Oaxaca

    Scientific Electronic Library Online (English)

    Gerardo, Rodrguez-Ortiz; Hctor M., De Los Santos-Posadas; Vctor A., Gonzlez-Hernndez; Arnulfo, Aldrete; Armando, Gmez-Guerrero; Aurelio M., Fierros-Gonzlez.

    Full Text Available El vigor de un rbol se puede evaluar a partir del follaje, que si bien representa de 4% a 6% de la biomasa total del rbol, es el componente principal para los procesos fisiolgicos. El objetivo de este estudio fue estimar la biomasa de acculas en ramas individuales y rbol completo, y ajustar mod [...] elos de particin de biomasa area en rboles plantados de Pinus patula Schl. et Cham. La biomasa de acculas por rama se estim con un modelo lineal, que emple rea basal de rama viva, altura de rama y el seccionamiento de copa como variables independientes. La biomasa de los componentes areos se estim con coeficientes de determinacin de 0,86; 0,92 y 0,88; para madera con corteza, ramas y acculas, respectivamente. Para madera con corteza se utiliz el dimetro normal (DN) y altura de rbol (AT) en un modelo lineal; la biomasa de ramas y follaje con ecuaciones no lineales que se basaron en el dimetro de copa viva (DCV) y rea de copa para ramas; y DCV y AT para la biomasa de follaje. La biomasa total area por rbol se estim con un R = 0,87; utilizando DN y AT. La biomasa a una edad de 14 aos se distribuy en 92,9%; 4,7% y 2,4% para madera, ramas y follaje, respectivamente. Abstract in english A forest tree health can be accurately assessed by evaluating foliage biomass; even when it represents only 4% to 6% of the total tree biomass, it is the main driver of every major physiological processes. This research was mainly focused on estimating accurately needle biomass at branch and tree le [...] vel on fast growing trees of Pinus patula Schl. et Cham. Needle biomass per branch was estimated with a linear model, which used live branch basal area, live branch height, and crown section like independent variables. Above ground components were estimated with determination coefficients of 0,86, 0,92 and 0,88 for wood with bark, branches and needles. For the wood with bark model, diameter at breast height (DBH) and total tree height (HT) were used in a linear structure; total branch biomass was fitted with a non-linear model, using live crown diameter (LCD) and crown area (CA) while total needle biomass used LCD and HT on a non-linear model. The aboveground total biomass per tree was estimated with R = 0.87, using DBH and HT. At 14 years old, biomass partition was estimated to be 92,9%, 4,7% and 2,4% for wood with bark, branches and needles, respectively.

  20. Biomasa de rotferos de dos embalses con diferentes estados trficos (Antioquia, Colombia) y su relacin con algunas variables limnolgicas / Rotifer biomass of two reservoirs with different trophic states (Antioquia, Colombia) and its relationship with some limnological variables

    Scientific Electronic Library Online (English)

    Silvia L, Villabona-Gonzlez; Robinson F, Buitrago-Amariles; John J, Ramrez-Restrepo; Jaime A, Palacio-Baena.

    2014-12-01

    Full Text Available Se evalu la variacin de la biomasa de rotferos en los ejes longitudinal y vertical de la zona ftica de los embalses La Fe y Riogrande II (Antioquia), Colombia, con diferentes estados trficos, durante los periodos de alta y baja precipitacin. Adems, se analiz su relacin con las variables tem [...] peratura, oxgeno disuelto, pH, transparencia, nutrientes y con la biomasa fitoplanctnica. La biomasa de rotferos fue dominada por Asplanchna girodi De Geurne 1888, en los dos embalses y fue significativamente mayor en el embalse de menor trofa. Aunque la biomasa de rotferos no mostr un gradiente longitudinal significativo, s present zonacin vertical dentro de la zona ftica, con mayor biomasa en el 10 y 1% de incidencia lumnica. Los patrones de variacin de la biomasa total de rotferos y de las especies dominantes estuvieron determinados principalmente por el ingreso de slidos suspendidos en el embalse de mayor trofa y por la biomasa y la densidad del fitoplancton en el embalse con menos nutrientes. A diferencia de lo esperado, la biomasa de los rotferos no fue favorecida por condiciones de mayor estado trfico, ya que el factor preponderante sobre la expresin de biomasa fue la calidad de los recursos alimenticios en cada embalse. Abstract in english Rotifers biomass was evaluated across longitudinal and vertical axes of the photic zone in the La Fe y Riogrande II reservoirs (Antioquia), Colombia, with different trophic states during periods of high and low precipitation. IN addition, its relationship with temperature, dissolved oxygen, pH, tran [...] sparency, nutrient availability, and phytoplankton biomass was analyzed. In both reservoirs, rotifer biomass was dominated by Asplanchna girodi De Geurne, 1888, and it was significantly higher in the reservoir with a lower trophic state. Even though rotifers biomass did not exhibit a longitudinal gradient, a vertical zonation in the photic zone was documented, with the greatest biomass at 10% and 1% of light intensity. Patterns of variation in total rotifer biomass and in dominant species biomass appear to be determined primarily by the entry of suspended solids into the reservoir with the higher trophic state, and by phytoplankton biomass and density in the reservoir with lower nutrient levels. Contrary to expectations, rotifer biomass was not favored by increasing trophic state. The most important factor determining rotifer biomass was the quality of food resources in each reservoir.

  1. Chapter 18: Web-based Tools - NED VO Services

    Science.gov (United States)

    Mazzarella, J. M.; NED Team

    The NASA/IPAC Extragalactic Database (NED) is a thematic, web-based research facility in widespread use by scientists, educators, space missions, and observatory operations for observation planning, data analysis, discovery, and publication of research about objects beyond our Milky Way galaxy. NED is a portal into a systematic fusion of data from hundreds of sky surveys and tens of thousands of research publications. The contents and services span the entire electromagnetic spectrum from gamma rays through radio frequencies, and are continuously updated to reflect the current literature and releases of large-scale sky survey catalogs. NED has been on the Internet since 1990, growing in content, automation and services with the evolution of information technology. NED is the world's largest database of crossidentified extragalactic objects. As of December 2006, the system contains approximately 10 million objects and 15 million multi-wavelength cross-IDs. Over 4 thousand catalogs and published lists covering the entire electromagnetic spectrum have had their objects cross-identified or associated, with fundamental data parameters federated for convenient queries and retrieval. This chapter describes the interoperability of NED services with other components of the Virtual Observatory (VO). Section 1 is a brief overview of the primary NED web services. Section 2 provides a tutorial for using NED services currently available through the NVO Registry. The "name resolver" provides VO portals and related internet services with celestial coordinates for objects specified by catalog identifier (name); any alias can be queried because this service is based on the source cross-IDs established by NED. All major services have been updated to provide output in VOTable (XML) format that can be accessed directly from the NED web interface or using the NVO registry. These include access to images via SIAP, Cone- Search queries, and services providing fundamental, multi-wavelength extragalactic data such as positions, redshifts, photometry and spectral energy distributions (SEDs), and sizes (all with references and uncertainties when available). Section 3 summarizes the advantages of accessing the NED "name resolver" and other NED services via the web to replace the legacy "server mode" custom data structure previously available through a function library provided only in the C programming language. Section 4 illustrates visualization via VOPlot of an SED and the spatial distribution of sources from a NED All-Sky (By Parameters) query. Section 5 describes the new NED Spectral Archive, illustrating how VOTables are being used to standardize the data and metadata as well as the physical units of spectra made available by authors of journal articles and producers of major survey archives; quick-look spectral analysis through convenient interoperability with the SpecView (STScI) Java applet is also shown. Section 6 closes with a summary of the capabilities described herein, which greatly simplify interoperability of NED with other components of the VO, enabling new opportunities for discovery, visualization, and analysis of multiwavelength data.

  2. A new three-dimensional vanadium selenite, (VO)(2)(SeO3)(3), with isolated and edge-shared VO6 octahedra

    OpenAIRE

    Halasyamani, PS; O'Hare, D.

    1997-01-01

    Single crystals of (VO)2(SeO3)3 have been prepared from SeO2 and V2O5. The crystal structure has been determined by single-crystal X-ray diffraction. Crystal data: (VO)2(SeO3)3, Mr = 514.75; monoclinic, space group P21a (No. 14); cell parameters a = 9.151(1) , b = 6.353(1) , c = 14.992(1), ? = 93.538(5), and Z = 4. The structure consists of VO6 octahedra and SeO3 groups. The vanadium octahedra either are edge-sharing and form [V2O6.66]3.33- groups or are corner-linked through an [SeO3/2]+...

  3. Individual plant and population biomass of dominant shrubs in Patagonian grazed fields / Biomasa individual y poblacional de arbustos dominantes en estepas patagnicas pastoreadas

    Scientific Electronic Library Online (English)

    Gastn R, Oatibia; Martn R, Aguiar; Pablo A, Cipriotti; Fernando, Troiano.

    2010-12-01

    Full Text Available La estimacin de la biomasa area de la vegetacin es clave para llevar a cabo estudios de Ecologa de Poblaciones, de Comunidades y de Ecosistemas. En sistemas dominados o codominados por leosas, esta estimacin es dificultosa, y es importante contar con mtodos rpidos y no destructivos. En este [...] estudio describimos cmo se distribuye la biomasa area en distintos componentes (i.e., leo, hojas) y cmo cambia con el tamao de arbusto para las tres especies dominantes de arbustos del Distrito Occidental de la estepa Patagnica. Adems, describimos la estructura poblacional de tamaos de las tres especies en campos pastoreados y estimamos su contribucin a la abundancia y la biomasa total a travs de un mtodo no destructivo. Desarrollamos ecuaciones alomtricas para estimar la biomasa de los componentes areos de los individuos de arbustos a partir de descriptores estructurales (i.e., dimetros y altura de la copa). La variable que mejor predijo la biomasa area en las tres especies de arbustos fue la suma de la altura y el dimetro promedio (entre el dimetro mayor y el perpendicular) de la copa. Los modelos alomtricos explicaron para cada especie ms de 83% de la variabilidad de la biomasa area individual. En el nivel de individuo, las especies tuvieron distinta proporcin de leo, hojas y distinto peso especfico del leo. El aumento del tamao individual de los arbustos fue acompaado por cambios en las proporciones de hojas/leo y en algunos casos por el porcentaje de copa muerta. En el nivel de poblacin, las tres especies difirieron en la distribucin de tamaos en pastizales pastoreados. La perspectiva poblacional utilizada para el desarrollo de los modelos alomtricos es clave para estudiar los procesos demogrficos que explican las respuestas de las comunidades y los ecosistemas ridos a los principales cambios ambientales y de uso. Abstract in english Estimating aboveground biomass of vegetation is essential for population, community and ecosystem studies. In systems dominated or co-dominated by woody species, biomass estimation is difficult, and rapid and non-destructive methods are needed. In this study, we describe biomass distribution in diff [...] erent components (i.e., wood, leaves) and how this changes with shrub size for the three dominant species of shrubs in the Occidental District of the Patagonian steppe. We also describe the population size structure of the three species in grazed fields and estimate their contribution to total abundance and biomass through a non-destructive method. We developed allometric equations to estimate aboveground biomass components of individual shrubs from structural descriptors (i.e., diameter and height of the crown), sampling individual plants of different sizes. The variable that best predicted biomass of the three species was the sum of the height and the average diameter of the crown (calculated with the largest diameter and its perpendicular). Allometric models for each species explained more than 83% of the variability of individual aboveground biomass. At the individual level, species had different proportions of wood, leaves and specific wood weight. Increasing shrub size was accompanied by changes in the proportion of leaves to wood, and in some cases, the percentage of dead crown. At the population level, the three species differed in size distribution in moderately grazed fields. Development of allometric models from a population perspective is important to study demographic processes that drive community and ecosystem responses to environmental and land-use changes.

  4. Estimacin de biomasa y carbono en dos especies arboreas en La Sierra Nevada, Mxico / Estimation of biomass and carbon in two arboreal species in the Sierra Nevada, Mexico

    Scientific Electronic Library Online (English)

    Fernando, Carrillo Anzres; Miguel, Acosta Mireles; Eulogio, Flores Ayala; Juana Eliud, Jurez Bravo; Eunice, Bonilla Padilla.

    2014-08-01

    Full Text Available Se generaron dos ecuaciones para determinar biomasa y carbono en Pinus montezumae y Alnus jorullensis H. B. K. ssp. jorullensis especies de importancia ecolgica de los bosques de la Sierra Nevada en el Estado de Mxico. Las ecuaciones que se determinaron son de la forma Y= bXk, donde Y es el conten [...] ido de biomasa o de carbono (kg) y X el dimetro normal (DN) en cm. Para estimar los valores b y k del modelo para cada especie, se utilizaron 15 rboles de Pinus montezumae y 16 de Alnus jorullensis ssp. jorullensis. En Pinus montezumae el mayor porcentaje de biomasa 77.07 % se estim en el fuste incluido el tocn, mientras que en las ramas y el follaje present 8.45 y 9.01%, respectivamente, con la biomasa y el DN de los rboles se obtuvo el ajuste de los parmetros b y k del modelo propuesto (B= 0.013 DN3.0462) con una R= 0.9909. Para el caso de Alnus jorullensis ssp. jorullensis de la misma forma el mayor porcentaje de biomasa 63.77% se estim en el fuste incluido el tocn, mientras que en las ramas y el follaje present 20.99 y 11.46%, respectivamente; con la biomasa y el DN de los rboles se obtuvo el ajuste de los parmetros b y k del modelo propuesto (B= 0.0195 DN2.7519) con una R= 0.9311. Despus de analizar el contenido de carbono en las muestra de cada especie, se ajustaron las ecuaciones para Pinus montezumae C= 0.0065DN3.0484, con una R= 0.9914, mientras que para Alnus jorullensis ssp. jorullensis C= 0.009DN2.7522con una R= 0.9313. Abstract in english Two equations were generated for determining the biomass and carbon in Pinus montezumae and Alnus jorullensis HBK ssp. jorullensis of ecological important species of the forests of the Sierra Nevada in the State of Mexico. The equations were determined are of the form Y= bXk, where Y is the biomass [...] content or carbon (kg) and X normal diameter (DN) in cm. For estimating the model and k values for each species, Pinus montezumae 15 trees and 16 Alnus jorullensis ssp. jorullensis were used. In Pinus montezumae the highest percentage of biomass was estimated at 77.07% including the stem stump, while the branches and foliage showed 8.45 and 9.01%, respectively, biomass and DN trees the adjustment is obtained by k parameters of the proposed model (B= 0.013 DN3.0462) with R= 0.9909. For the case of Alnus jorullensis ssp. jorullensis the same as the highest percentage of biomass was estimated at 63.77% including the stem stump, while the branches and foliage showed 20.99 and 11.46%, respectively; with biomass and tree DN setting the parameters of the proposed model by k (B= 0.0195 DN2.7519) with R= 0.9311 was obtained. After analyzing the carbon content in the sample of each species, the equations for Pinus montezumae C= 0.0065DN3.0484, with R= 0.9914, while for Alnus jorullensis ssp jorullensis was adjusted. C= 0.009DN2.7522 con an R= 0.9313.

  5. Estimacin de biomasa area en plantaciones de Cedrela odorata L. y Swietenia macrophylla King / Aerial biomass estimation in Cedrela odorata L. and Swietenia macrophylla King plantations

    Scientific Electronic Library Online (English)

    Agustn, Rueda Snchez; Agustn, Gallegos Rodrguez; Diego, Gonzlez Eguiarte; J. Ariel, Ruiz Corral; Juan de Dios, Benavides Solorio; Eduardo, Lpez Alcocer; Miguel, Acosta Mireles.

    2014-10-01

    Full Text Available Se evaluaron las capacidades de produccin de biomasa y de captura de carbono en plantaciones de Cedrela odorata y Swietenia macrophylla con 12 aos en el estado de Jalisco. En campo fueron seleccionados y derribados 15 rboles de cada especie para determinar la biomasa y el carbono en el estrato a [...] reo; se tomaron muestras del fuste, de las ramas (brazuelo y lea) y del follaje de cada individuo para conocer su peso fresco; en el laboratorio se secaron para obtener el peso seco y con estos datos se calcul la biomasa total de cada ejemplar a partir de la relacin peso seco: peso fresco. Para realizar las estimaciones se ajustaron ecuaciones de regresin tipo polinomial y potencial, el dimetro normal y la altura fueron las variables independientes. Al peso seco de cada componente del rbol se le aplic un ndice de captura de carbono de 0.4269 y con ello se obtuvo el potencial de captura de carbono atmosfrico. Para C. odorata el total de biomasa promedio por espcimen fue de 34 kg, en la que se distribuye 75 % de la biomasa en el fuste, 11 % en el brazuelo, 9 % en ramas (lea) y 5 % en el follaje. Para S. macrophylla el total de biomasa promedio por espcimen fue de 26 kg, del cual 47 % se distribuye en el fuste, 19 % en el brazuelo, 23 % en ramas y 10 % en el follaje. Abstract in english This study was conducted with the aim of assessing the ability of biomass production and carbon sequestration by plantations of Cedrela odorata and Swietenia macrophylla in a plantation established 12 years ago in the state of Jalisco, Mexico. At Costa de Jalisco Experimental Site of the Instituto N [...] acional de Investigaciones Forestales, Agrcolas y Pecuarias (INIFAP) and 15 trees of each species were selected and felled and the biomass and carbon in the aerial stratum were determined. Samples were taken from the stem, branches (twigs and firewood) and foliage of each of the selected trees and fresh weight was determined in the field from both species; the samples were dried in a laboratory to obtain the dry weight and estimate the total biomass of each tree using the ratio dry weight: fresh weight of samples. To estimate the biomass and carbon and polynomial regression equations were fit; the independent variables were normal diameter and tree height. To the dry weight of each tree component was applied a carbon sequestration index of 0.4269, thereby determining the potential for atmospheric carbon sequestration. For C. odorata, the total average biomass per tree was 34 kg, 75 % of which belongs to the biomass in the stem, 11 % in the trunk, 9 % in branches (wood) and 5 % in foliage. For S. macrophylla, the total average biomass per tree was 26 kg, which are distributed as 47 % in the stem, 19 % in the trunk, 23 % in branches and 10 % in the foliage.

  6. TiVo heitlus elu prast / John Gartner ; tlk. Peeter Peetersoo

    Index Scriptorium Estoniae

    Gartner, John

    2005-01-01

    Peale interaktiivse salvestusseadme TiVo turuletulekut 1997. aastal ei ole ettevte vaatamate toote headusele suutnud saavutada ootuspraseid mgitulemusi ega saada suurt kasumit. Artiklis tutvustatakse ettevtte heitlusi partnerite otsinguil ja edu saavutamisel

  7. Diode-pumped efficient Yb:YGdVO4 thin-disk laser

    International Nuclear Information System (INIS)

    We report for the first time a continuous wave Yb0.06:Y0.32Gd0.62VO4 (Yb:YGdVO4) laser, based on the 2F5/2 2F7/2 transition. The free running Yb:YGdVO4 thin-disk laser oscillation takes place at many different wavelengths, covering a wide range of 1037.0 1042.2, 1028.4 1040.2, and 1021.9 1031.2 nm, for transmissions 0.5%, 1.0%, and 2.0%, respectively. As in the case of the 0.2 mm thick a-cut Yb:YGdVO4 the most efficient laser operation was achieved employing the coupler of 0.5%, producing a maximum output power of 2.25 W which gives an optical-to-optical efficiency of 21.2%, the slope efficiency being 37.3%

  8. Phase Transition in strongly-correlated VO2: Time-domain Assignment of Cause and Effect

    Science.gov (United States)

    Cavalleri, A.; Dekorsy, Th.; Chong, H. H.; Kieffer, J. C.; Schoenlein, R. W.

    We establish time-domain hierarchy between structural and electronic effects in the strongly correlated system VO2. The insulator-to-metal transition is driven directly by structural change rather than by electron-electron correlations.

  9. Phase Transition in strongly-correlated VO2: Time-domainAssignment of Cause and Effect

    Energy Technology Data Exchange (ETDEWEB)

    Cavalleri, A.; Dekorsy, Th.; Chong, H.H.; Kieffer, J.C.; Schoenlein, R.W.

    2004-07-22

    We establish time-domain hierarchy between structural andelectronic effects in the strongly correlated system VO2. Theinsulator-to-metal transition is driven directly by structural changerather than by electron-electron correlations.

  10. Body fat, abdominal fat and body fat distribution related to VO(2PEAK) in young children

    DEFF Research Database (Denmark)

    Dencker, Magnus; Wollmer, Per; Karlsson, Magnus K; Lindn, Christian; Andersen, Lars Bo; Thorsson, Ola

    Abstract Objective. Aerobic fitness, defined as maximum oxygen uptake (VO(2PEAK)), and body fat measurements represent two known risk factors for disease. The purpose of this study was to investigate the relationship between VO(2PEAK) and body fat measurements in young children at a population......-based level. Methods. Cross-sectional study of 225 children (128 boys and 97 girls) aged 8-11 years, recruited from a population-based cohort. Total lean body mass (LBM), total fat mass (TBF), and abdominal fat mass (AFM) were measured by dual-energy x-ray absorptiometry. Body fat was also calculated as a...... percentage of body mass (BF%) and body fat distribution as AFM/TBF. VO(2PEAK) was assessed by indirect calorimetry during maximal exercise test. Results. Significant relationships existed between body fat measurements and VO(2PEAK) in both boys and girls, with Pearson correlation coefficients for absolute...

  11. Diamagnetic to ferromagnetic switching in VO2 epitaxial thin films by nanosecond excimer laser treatment

    Science.gov (United States)

    Molaei, R.; Bayati, R.; Nori, S.; Kumar, D.; Prater, J. T.; Narayan, J.

    2013-12-01

    VO2(010)/NiO(111) epitaxial heterostructures were integrated with Si(100) substrates using a cubic yttria-stabilized zirconia (c-YSZ) buffer. The epitaxial alignment across the interfaces was determined to be VO2(010)?NiO(111)?c-YSZ(001)?Si(001) and VO2[100]?NiO?110??c-YSZ?100??Si?100?. The samples were subsequently treated by a single shot of a nanosecond KrF excimer laser. Pristine as-deposited film showed diamagnetic behavior, while laser annealed sample exhibited ferromagnetic behavior. The population of majority charge carriers (e-) and electrical conductivity increased by about two orders of magnitude following laser annealing. These observations are attributed to the introduction of oxygen vacancies into the VO2 thin films and the formation of V3+ defects.

  12. Influence of thermal boundary conditions on the current-driven resistive transition in VO2 microbridges

    Science.gov (United States)

    Manca, Nicola; Kanki, Teruo; Tanaka, Hidekazu; Marr, Daniele; Pellegrino, Luca

    2015-10-01

    We investigate the resistive switching behaviour of VO2 microbridges under current bias as a function of temperature and thermal coupling with the heat bath. Upon increasing the electrical current bias, the formation of the metallic phase can progress smoothly or through sharp jumps. The magnitude and threshold current values of these sharp resistance drops show random behaviour and are dramatically influenced by thermal dissipation conditions. Our results also evidence how the propagation of the metallic phase induced by electrical current in VO2, and thus the shape of the resulting high-conductivity path, are not predictable. We discuss the origin of the switching events through a simple electro-thermal model based on the domain structure of VO2 films that can be useful to improve the stability and controllability of future VO2-based devices.

  13. Sr$_2$(Ba$_2$)VO$_4$ under pressure -- an orbital switch and potential $d^1$ superconductor

    CERN Document Server

    Arita, R; Held, K; Matsuno, J; Kuroki, K

    2006-01-01

    We study Sr$_2$(Ba$_2$)VO$_4$ under high pressure by means of the local density approximation + dynamical mean field theory method. While Sr$_2$VO$_4$ is a 1/6-filling three-band system at ambient pressure with a small level splitting between the $d_{xy}$- and $d_{yz/zx}$-bands, we show that an orbital polarization occurs under uniaxial pressure, resulting in dramatic changes of the magnetic, optical, and transport properties. When pressure is applied in the $c$-direction, a $d^1$ analog of $d^9$ cuprates is realized, making Sr$_2$(Ba$_2$)VO$_4$ a possible candidate for a $d^1$ superconductor. Experimentally, this uniaxial pressure can be realized by growing Ba$_2$VO$_4$ on a substrate with lattice constant 4.1-4.2 \\AA.

  14. VoIP for Telerehabilitation: A Pilot Usability Study for HIPAA Compliance

    Directory of Open Access Journals (Sweden)

    Valerie R. Watzlaf

    2012-06-01

    Full Text Available Consumer-based, free Voice and video over the Internet Protocol (VoIP software systems such as Skype and others are used by health care providers to deliver telerehabilitation and other health-related services to clients. Privacy and security applications as well as HIPAA compliance within these protocols have been questioned by practitioners, health information managers, and other healthcare entities. This pilot usability study examined whether four respondents who used the top three, free consumer-based, VoIP software systems perceived these VoIP technologies to be private, secure, and HIPAA compliant;  most did not.  While the pilot study limitations include the number of respondents and systems assessed, the protocol can be applied to future research and replicated for instructional purposes.  Recommendations are provided for VoIP companies, providers, and users. 

  15. Synthesis and characterization of VO2+ doped ZnO-CdS composite nanopowder

    Science.gov (United States)

    Thirumala Rao, G.; Babu, B.; Joyce Stella, R.; Pushpa Manjari, V.; Venkata Reddy, Ch.; Shim, Jaesool; Ravikumar, R. V. S. S. N.

    2015-02-01

    VO2+ doped ZnO-CdS composite nanopowder has been synthesized by chemical precipitation method. The prepared sample has been characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), FT-IR, photoluminescence (PL), optical absorption and EPR spectroscopy. From XRD pattern, average crystallite size is about 18 nm. SEM and TEM images showed sphere like structures. FT-IR spectrum indicates the presence of fundamental modes of ZnO, CdS and other functional groups. The PL spectrum of VO2+ doped ZnO-CdS composite nanopowder exhibits UV, blue and green emissions. Optical and EPR studies revealed the tetragonal compressed octahedral site symmetry for VO2+ ions. The bonding between VO2+ and its ligands is ionic.

  16. Body fat, abdominal fat and body fat distribution related to VO(2PEAK) in young children

    DEFF Research Database (Denmark)

    Dencker, Magnus; Wollmer, Per; Karlsson, Magnus K; Lindn, Christian; Andersen, Lars Bo; Thorsson, Ola

    -based level. Methods. Cross-sectional study of 225 children (128 boys and 97 girls) aged 8-11 years, recruited from a population-based cohort. Total lean body mass (LBM), total fat mass (TBF), and abdominal fat mass (AFM) were measured by dual-energy x-ray absorptiometry. Body fat was also calculated as a...... percentage of body mass (BF%) and body fat distribution as AFM/TBF. VO(2PEAK) was assessed by indirect calorimetry during maximal exercise test. Results. Significant relationships existed between body fat measurements and VO(2PEAK) in both boys and girls, with Pearson correlation coefficients for absolute...... values of VO(2PEAK) (0.22-0.36, P<0.05), and for VO(2PEAK) scaled by body mass (-0.38 - -0.70, P...

  17. High performance of solvothermally prepared VO2(B as anode for aqueous rechargeable lithium batteries

    Directory of Open Access Journals (Sweden)

    Miloevi? Sanja

    2015-01-01

    Full Text Available The VO2 (B was synthesized via a simple solvothermal route at 160oC in ethanol. The initial discharge capacity of VO2 (B anode, in saturated aqueous solution of LiNO3, was 177 mAh g-1 at a current rate of 50 mA g-1. After 50 cycles capacity fade was 4%, but from 20th-50th cycle no capacity drop was observed. The VO2 (B has shown very good cyclability at current rate of even 1000 mA g-1 with initial discharge capacity of 92 mAh g-1. The excellent electrochemical performance of VO2 (B was attributed to the stability of micro-nano structures to repeated intercalation /deintercalation process, very good electronic conductivity as well as the very low charge transfer resistance in the aqueous electrolyte. [Projekat Ministarstva nauke Republike Srbije, br. III45014

  18. High-temperature behavior of vanadyl pyrophosphate (VO)2P2O7

    International Nuclear Information System (INIS)

    (VO)2P2O7 has been studied at high temperatures by in situ X-ray powder diffraction in an inert atmosphere. Lattice parameters indicate an anisotropic thermal expansion up to Tc=214-bar C, followed by an approximately isotropic expansion up to 490-bar C. It is proposed that Tc is the temperature of a second-order phase transition between the known room temperature form with space group Pca21 and a high-temperature form with space group Pcab. Above 490-bar C a minority phase develops in the sample that was identified as the V3+ containing compound V4(P2O7)3, while the anisotropic expansion along a suggests that stoichiometric (VO)2P2O7 transforms into (VO)2P2O7+x with interstitial oxygen located between the layers. With an onset at 706-bar C all of the (VO)2P2O7 transforms into VPO4

  19. Mobile telephones: a comparison of radiated power between 3G VoIP calls and 3G VoCS calls.

    Science.gov (United States)

    Jovanovic, Dragan; Bragard, Guillaume; Picard, Dominique; Chauvin, Sbastien

    2015-01-01

    The purpose of this study is to assess the mean RF power radiated by mobile telephones during voice calls in 3G VoIP (Voice over Internet Protocol) using an application well known to mobile Internet users, and to compare it with the mean power radiated during voice calls in 3G VoCS (Voice over Circuit Switch) on a traditional network. Knowing that the specific absorption rate (SAR) is proportional to the mean radiated power, the user's exposure could be clearly identified at the same time. Three 3G (High Speed Packet Access) smartphones from three different manufacturers, all dual-band for GSM (900?MHz, 1800?MHz) and dual-band for UMTS (900?MHz, 1950?MHz), were used between 28 July and 04 August 2011 in Paris (France) to make 220 two-minute calls on a mobile telephone network with national coverage. The places where the calls were made were selected in such a way as to describe the whole range of usage situations of the mobile telephone. The measuring equipment, called "SYRPOM", recorded the radiation power levels and the frequency bands used during the calls with a sampling rate of 20,000 per second. In the framework of this study, the mean normalised power radiated by a telephone in 3G VoIP calls was evaluated at 0.75% maximum power of the smartphone, compared with 0.22% in 3G VoCS calls. The very low average power levels associated with use of 3G devices with VoIP or VoCS support the view that RF exposure resulting from their use is far from exceeding the basic restrictions of current exposure limits in terms of SAR. PMID:25352159

  20. Prior Knowledge of Trial Number Influences the Incidence of Plateau at VO2max

    Directory of Open Access Journals (Sweden)

    Dan Gordon

    2015-01-01

    Full Text Available The purpose of this study was to assess the VO2max plateau response at VO2max during a series of pre-determined trials. METHODS: Ten male well-trained athletes (age, 23.0 3.2; height, 183.3 5.5 cm; mass 77.5 11.1 Kg; VO2max 66.5 5.0 ml.kg-1,min-1, but who were VO2max testing nave and with prior-knowledge of trial number completed four incremental tests to volitional exhaustion, separated by ~72-h for the determination of VO2max and gas exchange threshold. Throughout all trials VO2max was recorded on a breath-by-breath basis using a pre-calibrated metabolic cart, using a plateau criterion of ? VO2 ?1.5 ml.kg-1.min-1 over the final 2 consecutive 30 s sampling periods. A significant difference was observed between trial-1 and trial-4 for plateau incidence (p = 0.0285 rising from 20% in trial-1 to a 70% response rate in trial-4. Furthermore a significant difference was observed for VO2dif (difference between criterion value and ? VO2 in trial-1, 1.02 1.69 ml.kg-1.min-1 (p = 0.038, with non-significant differences observed for all other trials, despite a non-significant difference for VO2max across all trials (p > 0.05. Finally, a significant difference was observed for effort perception (RPE at volitional exhaustion between trial-1 (17.7 1.3 and trial-4 (19.0 1.4 (p = 0.0052. These data indicate that prior-knowledge of trial number can influence the manifestation of the VO2 plateau in a group of well-trained male athletes, thereby suggesting that a form of effort control is established in order to preserve the finite anaerobic capacity.

  1. Relative Aerial Biomass Yield of Intercroped Alfalfa with Winter Forage Cereals / Rendimiento Relativo de Biomasa Area en Intercultivos de Alfalfa con Cereales Forrajeros de Invierno

    Scientific Electronic Library Online (English)

    Telmo, Pereyra; Hctor, Pagliaricci; Alfredo, Ohanian.

    2008-09-01

    Full Text Available En las regiones tropicales del mundo, el intercultivo est asociado con la produccin de granos para la alimentacin, mientras que en reas templadas recibe mayor atencin como medio de produccin eficiente de forraje. El objetivo de este experimento fue determinar el rendimiento relativo de biomasa [...] area en intercultivos de alfalfa (Medicago sativa L.) y cereales forrajeros de invierno. Se establecieron ocho sistemas producto de la combinacin con especies de cereales con distintas fechas de siembra. Las mediciones de biomasa se realizaron en tres situaciones: monocultivo de alfalfa, monocultivo de cereales e intercultivo de alfalfa-cereal, calculndose el rendimiento relativo del intercultivo (RRI). Se emple un diseo con arreglo bifactorial y dos repeticiones en bloques completos al azar. Los intercultivos de alfalfa-cereal generaron valores de RRI entre 0,71 y 0,83, lo que indic que en una misma superficie es posible producir entre el 71 y 83% de la biomasa que ambos cultivos produciran en superficies separadas. Abstract in english In the tropical regions of the world, intercropping is mostly associated with food grain production, whereas it is receiving increased attention in temperate regions as a means of efficient forage production. The aim of this work was to determine the relative yield of aerial biomass in alfalfa or lu [...] cerne (Medicago sativa L.) and winter forage cereals intercrops. These were done in eight systems resulting from the combination of species sown at different dates. The biomass was measured in three situations: alfalfa and cereal sole-crop and alfalfa-cereal intercrops, the relative biomass yields were calculated by the relative yield index (RYI). The field experiment was conducted as a bifactorial array in a randomized complete block design of two replicates. The alfalfa-cereal intercrops provided RYI values ranging from 0.71 to 0.83. This showed that it is possible to produce, in the same area, between 71 and 83% of the biomass that both crops would produce in separate ones.

  2. Carbono almacenado en la biomasa area de plantaciones de araucaria (Araucaria angustifolia -Bert.- O. Ktze) / Aboveground carbon stocks in plantations of araucaria (Araucaria angustifolia -Bert.- O. Ktze)

    Scientific Electronic Library Online (English)

    Jos D, Vega; Rodolfo, Martiarena.

    2010-06-01

    Full Text Available En este trabajo se estima el carbono areo almacenado en plantaciones de Araucaria angustifolia (Bert.) O. Ktze de diferentes edades, localizadas en el norte de la provincia de Misiones. Se determina la biomasa area por muestreo destructivo de rboles de 1, 2, 3, 6, 20, 30 y 40 aos de edad, se aju [...] stan ecuaciones para estimar el peso seco de los restantes rboles de la parcela y se calcula la biomasa y el carbono en la totalidad de la plantacin de cada una de las edades. El carbono almacenado en la biomasa area es de 0,04; 0,31; 1,3; 21,9; 56,2; 60,5 y 92,2 Mg.ha-1 para las edades de 1, 2, 3, 6, 20, 30 y 40 aos respectivamente. Abstract in english This work estimated the aboveground carbon stock in plantations of Araucaria angustifolia -Bert.- O. Ktze of different ages, located in the north of the province of Misiones. The aboveground biomass was determined by destructive sampling of trees of 1, 2, 3, 6, 20, 30 and 40 years of age, equations [...] were adjusted to estimate the dry weight of the remaining trees of the plot and biomass and carbon were calculated in the whole plantation of exemplars of all the ages mentioned. The carbon of the total aboveground biomass is 0,04; 0,31; 1,3; 21,9; 56,2; 60,5 and 92,2 Mg.ha-1 for tree ages 1, 2, 3, 6, 20, 30 and 40, respectively.

  3. Evolution of Spin-Orbital-Lattice Coupling in the $R$VO$_3$ Perovskites

    OpenAIRE

    Horsch, Peter; Oles, Andrzej M.; Feiner, Louis Felix; Khaliullin, Giniyat

    2008-01-01

    We introduce a microscopic model which unravels the physical mechanisms responsible for the observed phase diagram of the $R$VO$_3$ perovskites. It reveals a nontrivial interplay between superexchange, the orbital-lattice coupling due to the GdFeO$_3$-like rotations of the VO$_6$ octahedra, and orthorhombic lattice distortions. We find that the lattice strain affects the onset of the magnetic and orbital order by partial suppression of orbital fluctuations. The present approach provides also ...

  4. Malicious traffic monitoring and its evaluation in VoIP infrastructure

    OpenAIRE

    Safarik, Jakub; Voznak, Miroslav; Rezac, Filip; Macura, Lukas

    2012-01-01

    The paper deals with the need to enhance security of the VoIP infrastructure. There are several ways to achieve an enhancement in security. We opted for the honeypot which can provide us information about attackers behaviour. We will examine in particular a VoIP honeypot referred to as Artemisa. It is one of many existing honeypots tailored for IP telephony. The paper describes its function and application within a real IP telephony infrastructure. The aim of another tes...

  5. Self-Assembly and Horizontal Orientation Growth of VO2 Nanowires

    OpenAIRE

    Chun Cheng; Hua Guo; Abbas Amini; Kai Liu; Deyi Fu; Jian Zou; Haisheng Song

    2014-01-01

    Single-crystalline vanadium dioxide (VO2) nanostructures have attracted an intense research interest recently because of their unique single-domain metal-insulator phase transition property. Synthesis of these nanostructures in the past was limited in density, alignment, or single-crystallinity. The assembly of VO2 nanowires (NWs) is desirable for a bottom-up approach to the engineering of intricate structures using nanoscale building blocks. Here, we report the successful synthesis of hori...

  6. QoS Analysis for Signaling in VoIP Client and Server Communication for Multicore

    OpenAIRE

    Adnan, Muhammad

    2012-01-01

    Due to the cost-effective solutions provided by Voice over Internet Protocol (VoIP) technology to enterprises and individuals, the growth has been significantly high in this area during the past and current decade. The growing demand has resulted in the escalating number of users who need secure, reliable and efficient communication systems. The deployment of multicore hardware has been solving the computational complexity problems. A multicore hardware/software model for VoIP is the key rese...

  7. Size and composition-controlled fabrication of VO2 nanocrystals by terminated cluster growth

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre; Slack, Jonathan

    2013-05-14

    A physical vapor deposition-based route for the fabrication of VO2 nanoparticles is demonstrated, consisting of reactive sputtering and vapor condensation at elevated pressures. The oxidation of vanadium atoms is an efficient heterogeneous nucleation method, leading to high nanoparticle throughtput. Fine control of the nanoparticle size and composition is obtained. Post growth annealing leads to crystalline VO2 nanoparticles with optimum thermocromic and plasmonic properties.

  8. VoIP: A Corporate Governance Approach to Avoid the Risk of Civil Liability

    OpenAIRE

    Mariana Gerber; Kerry-Lynn Thomson; Tian Gerber

    2013-01-01

    Since the deregulation of Voice over Internet Protocol (VoIP) in 2005, many South African organizations are now attempting to leverage its cost saving and competitive values. However it has been recently cited that VoIP is one of the greatest new risks to business. This risk is cited to increase Information Security insurance premiums in the near future. Due to the dynamic nature of the technology, regulatory and legislative concerns such as lawful interception of communications and privacy m...

  9. A novel approach for security issues in VoIP networks in Virtualization with IVR

    OpenAIRE

    Kinjal Shah; Satya Prakash Ghrera; Alok Thaker

    2012-01-01

    VoIP (Voice over Internet Protocol) is a growing technology during last decade. It provides the audio, video streaming facility on successful implementation in the network. However, it provides the text transport facility over the network. Due to implementation of it the cost effective solution, it can be developed for the intercommunication among the employees of a prestigious organization. The proposed idea has been implemented on the audio streaming area of the VoIP technology. In the ...

  10. Voltage-controlled switching and thermal effects in VO{sub 2} nano-gap junctions

    Energy Technology Data Exchange (ETDEWEB)

    Joushaghani, Arash; Jeong, Junho; Stewart Aitchison, J.; Poon, Joyce K. S. [Department of Electrical and Computer Engineering, University of Toronto, 10 King' s College Road, Toronto, Ontario M5S 3G4 (Canada); Paradis, Suzanne; Alain, David [Defence Research and Development Canada - Valcartier, 2459 Pie-XI Blvd. North, Quebec, Quebec G3J 1X5 (Canada)

    2014-06-02

    Voltage-controlled switching in lateral VO{sub 2} nano-gap junctions with different gap lengths and thermal properties was investigated. The effect of Joule heating on the phase transition was found to be strongly influenced by the device geometry, the contact material, and the current. Our results indicate that the VO{sub 2} phase transition was likely initiated electronically, which was sometimes followed by a secondary thermally induced transition.

  11. Voltage-controlled switching and thermal effects in VO2 nano-gap junctions

    International Nuclear Information System (INIS)

    Voltage-controlled switching in lateral VO2 nano-gap junctions with different gap lengths and thermal properties was investigated. The effect of Joule heating on the phase transition was found to be strongly influenced by the device geometry, the contact material, and the current. Our results indicate that the VO2 phase transition was likely initiated electronically, which was sometimes followed by a secondary thermally induced transition.

  12. Magnetic field dependence of the cooperative Jahn-Teller distortion in DyVO4

    International Nuclear Information System (INIS)

    The Jahn-Teller induced orthorhombic distortion in DyVO4 has been determined as a function of temperature and magnetic field up to 13 T by measurement of splitting of Esub(g) phonon modes of the tetragonal phase. The results are not well predicted by molecular field theory, reinforcing the conclusion from other experiments that short-range interactions are dominant in DyVO4. (author)

  13. Synthesis and characterization of Ag/BiVO4 composite photocatalyst

    International Nuclear Information System (INIS)

    Ag/BiVO4 composite photocatalysts were hydrothermal synthesized and characterized by XRD, SEM, XPS and DRS techniques. Their photocatalytic activities were determined by oxidative decomposition of methyl orange in aqueous solution under visible light irradiation. It revealed that the doped Ag species greatly improved the visible light absorption abilities and morphologies of the composites, and thus lead to enhanced photocatalytic activities compared with that of the pure BiVO4.

  14. Prepaid and Postpaid VoIP Service Enhancements and Hybrid Network Performance Measurement

    OpenAIRE

    Mohd Nazri Ismail; Asaad Abusin

    2006-01-01

    This study focuses on prepaid and postpaid VoIP technology service enhancement. The aims are to i) merge wireless technology in rural areas with wired technologies and services in urban areas. It intends to investigate the minimum requirement needs by wireless and wired technology in using of telco connectivity. It is also to define which technology will achieve a low operating cost and good performance. In addition, the most apparent benefit of implementing prepaid/postpaid VoIP network in r...

  15. VO Access to the HST Snapshot Survey of 3C Radio Galaxies

    Science.gov (United States)

    Allen, Mark

    2007-08-01

    HST snapshot surveys of the 3C sample of radio galaxy hosts have collected a wealth of UV, optical and IR imaging data on these objects. We describe how science-ready data from these surveys is being made available in the VO via the Systme Automatique d'Archivage de Donnes Astronomiques' (SAADA) database generator, and how it is being exploited with VO tools.

  16. Cardiac output distribution in miniature swine during locomotory exercise to VO/sub 3max/

    International Nuclear Information System (INIS)

    Distribution of cardiac output (CO) was studied in miniature swine (22 +/- 1 kg) during level treadmill exercise up to the speed (17.7 km/hr) that elicited maximal oxygen consumption (VO/sub 2max/) (60 +/- 4 m1/min/kg). COs and tissue blood flows (BFs) were measured with the radiolabelled microsphere technique. CO increased from a preexercise value of 2.1 +/- 0.5 1/min up to 9.9 +/- 0.5 1/min at VO/sub 2max/. In preexercise standing 43% of CO went to skeletal muscle, which comprised 36 +/- 1% of body mass, 42% to viscera (12 +/- 1% mass), 5% to brain, heart, and lungs (2% +/- 0.1% mass), and 10% to skin and skeleton (35 +/- 2% mass). Preexercise could not be considered resting because of the animals' excitability. Skeletal muscle BF increased progressively with speed up to VO/sub 2max/, both in absolute terms and in percent CO. At VO/sub 2max/, 88% of CO went to muscle, 3% to viscera, 8% to brain, heart and lungs, and 1% to skin and skeleton. Thus, at VO/sub 2max/ only 4% of CO went to the inactive tissues, which constituted 47% of body mass. In 2 pigs that ran at speeds above 17 km/hr, total muscle BF leveled off at VO/sub 2max/. These findings demonstrate that muscle BF progressively increases up to VO/sub 2max/, and that VO2 levels off at the same intensity as muscle flow

  17. The relationship between speed and aerobic endurance (vo2max) in prepubertal children

    OpenAIRE

    Tar?k Sevindi; Seluk zda?; etin Yaman; Recep Krk; Hale Hazar; Fatih Hazar

    2009-01-01

    The aim of this study was to determine the relationship between speed and aerobic endurance (VO2max) in prepubertal children. A total of twenty-three prepubertal children (age 11.440.72y); thirteen boys and ten prepubertal girls took part in this study. Each subject performed 20 m sprint test and 20m Shuttle Run Test. The relationship between speed and VO2max was analyzed by Spearman Correlation Test (p

  18. Slow component of VO2 kinetics: mechanistic bases and practical applications.

    Science.gov (United States)

    Jones, Andrew M; Grassi, Bruno; Christensen, Peter M; Krustrup, Peter; Bangsbo, Jens; Poole, David C

    2011-11-01

    The VO? slow component, a slowly developing increase in VO? during constant-work-rate exercise performed above the lactate threshold, represents a progressive loss of skeletal muscle contractile efficiency and is associated with the fatigue process. This brief review outlines the current state of knowledge concerning the mechanistic bases of the VO? slow component and describes practical interventions that can attenuate the slow component and thus enhance exercise tolerance. There is strong evidence that, during constant-work-rate exercise, the development of the VO? slow component is associated with the progressive recruitment of additional (type II) muscle fibers that are presumed to have lower efficiency. Recent studies, however, indicate that muscle efficiency is also lowered (resulting in a "mirror-image" VO? slow component) during fatiguing, high-intensity exercise in which additional fiber recruitment is unlikely or impossible. Therefore, it seems that muscle fatigue underpins the VO? slow component, although the greater fatigue sensitivity of recruited type II fibers might still play a crucial role in the loss of muscle efficiency in both situations. Several interventions can reduce the magnitude of the VO? slow component, and these are typically associated with an enhanced exercise tolerance. These include endurance training, inspiratory muscle training, priming exercise, dietary nitrate supplementation, and the inspiration of hyperoxic gas. All of these interventions reduce muscle fatigue development either by improving muscle oxidative capacity and thus metabolic stability or by enhancing bulk muscle O2 delivery or local QO?-to-VO? matching. Future honing of these interventions to maximize their impact on the VO? slow component might improve sports performance in athletes and exercise tolerance in the elderly or in patient populations. PMID:21552162

  19. Li+ intercalation in isostructural Li2VO3 and Li2VO2 with O2- and mixed O2-/F- anions

    OpenAIRE

    Chen, R.; Ren, S; YAVUZ, M.; Guda, A. A.; Shapovalov, V.; Witter, R.; Fichtner, M.; Hahn, H.

    2015-01-01

    Mixed-anion materials for Li-ion batteries have been attracting attention in view of their tunable electrochemical properties. Herein, we compare two isostructural (Fm3m) model intercalation materials Li2VO3 and Li2VO2F with O2- and mixed O2-/F- anions, respectively. Synchrotron X-ray diffraction and pair distribution function data confirm large structural similarity over long-range and at the atomic scale for these materials. However, they show distinct electrochemical properties and kinetic...

  20. Equaes para a previso da potncia aerbia (VO2 de jovens adultos brasileiros Equations for predicting aerobic power (VO2 of young Brazilian adults

    Directory of Open Access Journals (Sweden)

    Paula Magrani

    2010-06-01

    Full Text Available FUNDAMENTO: O VO2 pode ser previsto, com base em parmetros antropomtricos e fisiolgicos, para determinadas populaes. OBJETIVO: Propor modelos preditivos do VO2 submximo e mximo para jovens adultos brasileiros. MTODOS: Os 137 voluntrios (92 homens foram submetidos ao teste progressivo de esforo mximo (GXT no ciclo ergmetro (Monark, Br. Medidas de trocas gasosas e ventilatrias foram realizadas em circuito aberto (Aerosport TEEM 100, EUA. Em outro grupo, 13 voluntrios foram submetidos ao GXT e a um teste de onda quadrada (SWT, para avaliar a validade externa das frmulas do ACSM, de Neder et al e do nomograma de strand-Ryhming. Adotou-se o delineamento experimental de validao cruzada e o nvel de significncia de p BACKGROUND: VO2 may be predicted with base on anthropometric and physiological parameters for determined populations. OBJECTIVE: To propose models for submaximal and maximal VO2 prediction in young Brazilian adults. METHODS: A total of 137 volunteers (92 men underwent graded maximal exercise test (GXT in a cycle ergometer (MonarkTM, Br. Gas exchange and respiratory measurements were performed in an open circuit (AerosportTM TEEM 100, USA. In another group, 13 volunteers underwent GXT and a square wave test (SWT in order to evaluate the external validity of Neder et al's formula, ACSM's formula, and of strand-Ryhming nomogram. The study design chosen was a cross-validation and the significance level was set at p < 0.05. RESULTS: For men during submaximal exercises, a mathematical model was deduced with base on workload, body mass, and age, which explained 89% of the VO2 variation, with SEE (standard error of the estimate = 0.33 l.min-1. For the maximum load in the male group, another model with the same variables explained 71% of VO2 variation, with SEE = 0.40 l.min-1. For women, 93% of VO2 variation could be explained, with SEE = 0.17 l.min-1, both in submaximal and maximal exercise, with only one equation by use e of the same independent variables. CONCLUSION: The models derived in the present study proved to be accurate to predict submaximal and maximal VO2 in young Brazilian adults. (Arq Bras Cardiol. 2010; [online]. ahead print, PP.0-0

  1. Determinacin de carbono orgnico total presente en el suelo y la biomasa de los pramos de las comunidades de chimborazo y shobol llinllin en Ecuador

    Directory of Open Access Journals (Sweden)

    M. Echeverra

    2013-01-01

    Full Text Available En la determinacin del contenido de carbono orgnico total presente en el suelo y la biomasa (cobertura vegetal de los pramos de las comunidades de Chimborazo, con 210ha de pramo cuya ubicacin es 746667UTM-9825400UTM, y Shobol Llinlln, con 350 ha de pramo, 754680UTM9854678UTM, pertenecientes a San Juan en Ecuador, se seleccionaron 9 puntos de muestreo de acuerdo a la variacin, caractersticas y altitud del suelo, repartidos para este estudio en tres pisos altitudinales comprendidos, para el pramo de la comunidad Chimborazo, entre 3600-3900 msnm y, en el caso de Shobol Llinlln, entre 3600-3950 msnm.

  2. Biomasa de la vegetacin herbacea y leosa pequea y necromasa en el rea de influencia de la central hidroelctrica Porce II

    OpenAIRE

    HERRERA ARANGO, MARA ALEJANDRA

    2002-01-01

    Este trabajo se realiz en los bosques primarios y secundarios del rea de influencia de la Central Hidroelctrica Porce II, en el departamento de Antioquia, Colombia. La regin se encuentra entre 925 y 1500 msnm, con una precipitacin promedia anual de 3050 mm/ao. Se cuantific el aporte de la vegetacin herbcea y leosa pequea (VH&LP) como parte de la biomasa area, as como el aporte de los detritos vegetales tanto en el suelo como el vuelo (hojarasca fina, detritos de madera gruesa y ...

  3. Estimacin de la biomasa foliar de Prosopis flexuosa mediante relaciones alomtricas Estimation of leaf biomass in Prosopis flexuosa by means of allometric relationships

    Directory of Open Access Journals (Sweden)

    M. Ledesma

    2010-12-01

    Full Text Available La estimacin alomtrica de la biomasa foliar arbrea es necesaria para determinar la produccin primaria y para analizar algunas de las interacciones ecolgicas entre los rboles y los dems componentes de la vegetacin. El objetivo del trabajo fue ajustar y seleccionar modelos para estimar la biomasa foliar de Prosopis flexuosa a partir de variables dendromtricas. Se apearon seis rboles, se midi su dimetro y se calcul el rea de albura de muestras transversales de leo, en cuatro niveles: en los rdenes de ramificacin dentro de la copa viva (ramas secundarias, terciarias y cuaternarias agrupadas, en el extremo distal de las ramas primarias y en los extremos distal y basal del fuste. Se recolectaron las hojas correspondientes a cada nivel y se obtuvo el peso seco. El rea de albura fue la mejor variable predictora de biomasa foliar, aunque el dimetro tuvo buen ajuste en ramas dentro de la copa viva y en ramas primarias. Los modelos calculados con variables de fuste tuvieron menor ajuste. Se concluye que para la estimacin no destructiva de la biomasa foliar de plantas adultas de Prosopis flexuosa es recomendable utilizar el modelo basado en el dimetro distal de las ramas primarias.The estimation of leaf biomass, usually performed by alometric relations, is important for the interpretation of primary production and for the assessment of ecological interactions between trees and the rest of the components in a wood vegetation. The goal for the present work was to adjust and to select allometric models for the estimation of leaf biomass Prosopis flexuosa based on dendrometric variables. Six trees were surveyed. The diameter and sapwood area of transversal samples of wood were determined at four different levels: in the orders of ramification within living crown (secondary, tertiary and quaternary grouped branches, at the distal portions of primary branches and in the apical and basal portions of bole. The leaves were collected according to each level and dry mass was obtained. The sapwood area was the best predictor of leaf biomass, although diameter provided accurate estimations within crown and at the distal portions of primary branches. The models based on trunk dimensions were less precise. It is concluded that the obtained regression model based on the diameter of the distal portions of primary branches can be applied for the non-destructive estimation of leaf biomass in Prosopis flexuosa adult trees.

  4. Produccin de biomasa de la microalga Scenedesmus sp. utilizando aguas residuales de pescadera / Biomass production of microalga Scenedesmus sp. with wastewater from fishery

    Scientific Electronic Library Online (English)

    Charity E, Andrade R; Alexandra L, Vera B; Carmen H, Crdenas L; Ever D, Morales A.

    2009-08-01

    Full Text Available Las microalgas representan una alternativa para el tratamiento de aguas residuales por su capacidad de remocin de nutrientes y alto valor comercial de la biomasa producida. Se evalu el crecimiento, remocin de nutrientes y materia orgnica de la microalga Scenedesmus sp. en aguas residuales deriva [...] das de restos de pescadera. Se utilizaron cultivos discontinuos en tanques a cielo abierto con 150L, aireacin constante y en condiciones no controladas de fotoperiodo y temperatura. Se evalu el crecimiento de la microalga mediante recuento celular, peso seco y contenido de pigmentos, realizando la recoleccin de la misma en fase estacionaria mediante sedimentacin natural, y efectuando anlisis fisicoqumicos a la biomasa secada al sol. La microalga creci en agua residual a cielo abierto, reportando eficiencias de remocin de 94,44% (23,80mg/L) para nitrgeno amoniacal, de 77,54% (7,04mg/L) para fosfatos y de 35,59% (26,09mg/L) para materia orgnica. La biomasa seca result ser un componente de alto contenido proteico (24,41%), fibroso (10,04%), con niveles de grasa (2,47%) y minerales (23,52%) adecuados para complementar la nutricin animal. Estos resultados demostraron que Scenedesmus puede ser utilizada para el tratamiento de aguas residuales con la produccin de una biomasa de valor agregado. Abstract in english The microalgae represent an alternative for the treatment of wastewater for his capacity of removal of nutrients and high commercial value of produced biomass. There was evaluated the growth, removal of nutrients and organic matter of Microalgae Scenedesmus sp. in wastewater derived from remains of [...] fish. Discontinuous cultures were in use in tanks to sky opened with 150L, constant aeration and in conditions no controlled of photoperiod and temperature. The growth of microalgae we evaluated by means of cell counting, dry weight and content of pigments, realizing the compilation of the same one in stationary phase by means of natural sedimentation, and effecting physicochemical analyses to the biomass dried to the sun. The microalgae grew in wastewater to opened sky, reporting efficiencies of removal of 94.44% (23.80 mg/L) for ammonia nitrogen, 77.54% (7.04 mg/L) for phosphates and 35.59 % (26.09 mg/L) for organic matter. The dry biomass recollected was a component of high contained protein (24,41%), fibrous (10,04%), with levels of fats (2,47%) and mineral (23,52%) adapted to complement the animal nutrition. These results showed that Scenedesmus can be used for the treatment of wastewater by production of a biomass of added value.

  5. Influencia de la aplicacin de vinaza en actividad y biomasa microbiana en un entic dystropept y un fluventic haplustoll del valle del cauca, colombia

    OpenAIRE

    Sandra Patricia Montenegro Gmez; Juan Carlos Menjivar Flrez; Carmen Rosa Bonilla Correa; Ral Madrin Molina

    2009-01-01

    Con la aplicacin de vinaza, residuo de la produccin de alcohol carburante a partir de la caa de azcar, se evalu el efecto sobre la actividad y biomasa microbiana del suelo y el suministro de K+ al cultivo de maz dulce (Zea Mays)...

  6. Biomass and densityofthalassia testudinum beds in mochimabay, Venezuela Biomasa y densidad de praderas de thalassia testudinum en la bahía de mochima, Venezuela

    OpenAIRE

    Díaz-Díaz,Oscar; Liñero-Arana, Ildefonso

    2007-01-01

    Un estudio acerca de las variaciones de la biomasa y densidad de Thalassia testudinum fue realizado en cuatro localidades de la Bahía de Mochima, en la costa nororiental de Venezuela. Entre enero y diciembre de 2002, se tomaron ocho réplicas mensuales de sedimento, empleando un perforador de PVC de 15 cm de diámetro, las mismas fueron tamizadas en una malla de 0,5 mm de apertura. El promedio de la temperatura y salinidad fue o = 27,82 ± 1,26 y = 37,09 ± 0,86 respectivamente. La densidad mens...

  7. Stream or Block Cipher for Securing VoIP?

    Directory of Open Access Journals (Sweden)

    Ashraf D. Elbayoumy

    2007-09-01

    Full Text Available When the network is homogeneous, choosing the cipher type for apacket telephony application is simple. It is clear that streamciphers perform better than block ciphers over landline,circuit-switched networks, since loss is negligible in thesenetworks but corruption is not. Likewise, it is also clear thatblock ciphers perform better than stream ciphers over landline,packet-switched networks, since corruption is negligible in thesenetworks but loss is not [9]. However, the choice of cipheris not so clear for a heterogeneous internetwork containing a mixof packet and circuit-switched networks. Additionally, this issuebecomes even more confounded when heterogeneous internetwork alsoconsists of wireless links. Existing encryption systems willdegrade performance in a heterogeneous internetwork because suchinternetworks have appreciable loss and corruption. Thus, theerror properties would degrade the subjective quality of thepacket telephony application. In this paper we present anexperimental results of comparing block and stream ciphers whenused to secure VoIP in terms of end-to-end delay and subjectivequality of perceived voice.We proposed a new technique, which provides automaticsynchronization of stream ciphers on a per packet basis, withoutthe overhead of an initialization vector in packet headers orwithout maintaining any state of past-encrypted data. We show thatthis technique mitigates the trade-off between subjective qualityand confidentiality.

  8. Transport phenomena in SrVO3 thin films

    Science.gov (United States)

    Gu, Man; Wolf, Stuart; Lu, Jiwei; University of Virginia Team

    2013-03-01

    Bulk SrVO3 (SVO) with a 3d1 electronic configuration has been found to exhibit metallic and Pauli paramagnetic behavior. We have obtained epitaxial SVO films grown on various substrates (STO, SLAO, LSAT and LAO) using a pulsed electron-beam deposition (PED) technique. The film transport properties were found to be strongly dependent on the substrate. A 40 nm SVO film deposited on an STO substrate exhibited metallic behavior with the electrical resistivity following a T2 law that corresponds to a Fermi liquid system, the resistance ratio R(300K)/R(2K) was ~ 1.66. Hall measurements showed that the mobility increased slightly as the temperature was decreased. A small positive out-of-plane magnetoresistance was observed, it was only 0.045% at 5 K and 7 Tesla. SVO films with the same thickness grown on SLAO, LSAT and LAO showed semiconducting behavior, the different transport properties in the SVO films could be attributed to the compressive film strain or the different film-substrate interfaces.

  9. The Gaia Archive at ESAC: a VO-inside archive

    Science.gov (United States)

    Gonzalez-Nunez, J.

    2015-12-01

    The ESDC (ESAC Science Data Center) is one of the active members of the IVOA (International Virtual Observatory Alliance) that have defined a set of standards, libraries and concepts that allows to create flexible,scalable and interoperable architectures on the data archives development. In the case of astronomy science that involves the use of big catalogues, as in Gaia or Euclid, TAP, UWS and VOSpace standards can be used to create an architecture that allows the explotation of this valuable data from the community. Also, new challenges arise like the implementation of the new paradigm "move code close to the data", what can be partially obtained by the extension of the protocols (TAP+, UWS+, etc) or the languages (ADQL). We explain how we have used VO standards and libraries for the Gaia Archive that, not only have producing an open and interoperable archive but, also, minimizing the developement on certain areas. Also we will explain how we have extended these protocols and the future plans.

  10. VO-KOREL: A Fourier disentangling service of Virtual Observatory

    CERN Document Server

    koda, Petr; Fuchs, Jan

    2011-01-01

    VO-KOREL is a web service exploiting the technology of Virtual Observatory for providing the astronomers with the intuitive graphical front-end and distributed computing back-end running the most recent version of Fourier disentangling code KOREL. The system integrates the ideas of the e-shop basket, conserving the privacy of every user by transfer encryption and access authentication, with features of laboratory notebook, allowing the easy housekeeping of both input parameters and final results, as well as it explores a newly emerging technology of cloud computing. While the web-based front-end allows the user to submit data and parameter files, edit parameters, manage a job list, resubmit or cancel running jobs and mainly watching the text and graphical results of a disentangling process, the main part of the back-end is a simple job queue submission system executing in parallel multiple instances of FORTRAN code KOREL. This may be easily extended for GRID-based deployment on massively parallel computing cl...

  11. On-line Monitoring of VoIP Quality Using IPFIX

    Directory of Open Access Journals (Sweden)

    Petr Matousek

    2014-01-01

    Full Text Available The main goal of VoIP services is to provide a reliable and high-quality voice transmission over packet networks. In order to prove the quality of VoIP transmission, several approaches were designed. In our approach, we are concerned about on-line monitoring of RTP and RTCP traffic. Based on these data, we are able to compute main VoIP quality metrics including jitter, delay, packet loss, and finally R-factor and MOS values. This technique of VoIP quality measuring can be directly incorporated into IPFIX monitoring framework where an IPFIX probe analyses RTP/RTCP packets, computes VoIP quality metrics, and adds these metrics into extended IPFIX flow records. Then, these extended data are stored in a central IPFIX monitoring system called collector where can be used for monitoring purposes. This paper presents a functional implementation of IPFIX plugin for VoIP quality measurement and compares the results with results obtained by other tools.

  12. Continuous tuning of W-doped VO{sub 2} optical properties for terahertz analog applications

    Energy Technology Data Exchange (ETDEWEB)

    Karaoglan-Bebek, G. [Department of Physics and Nano Tech Center, Texas Tech University, Lubbock, Texas 79409 (United States); Hoque, M. N. F.; Fan, Z.; Bernussi, A. A., E-mail: ayrton.bernussi@ttu.edu [Department of Electrical and Computer Engineering and Nano Tech Center, Texas Tech University, Lubbock, Texas 79409 (United States); Holtz, M. [Department of Physics, Texas State University, San Marcos, Texas 78666 (United States)

    2014-11-17

    Vanadium dioxide (VO{sub 2}), with its characteristic metal-insulator phase transition, is a prospective active candidate to realize tunable optical devices operating at terahertz (THz) frequencies. However, the abrupt phase transition restricts its practical use in analog-like continuous applications. Incorporation of tungsten is a feasible approach to alter the phase transition properties of thin VO{sub 2} films. We show that amplitude THz modulation depth of ?65%, characteristic phase transition temperature of ?40?C, and tuning range larger than 35?C can be achieved with W-doped VO{sub 2} films grown on sapphire substrates. W-doped VO{sub 2} films can also be used to suppress Fabry-Perot resonances at THz frequencies but at temperatures much lower than that observed for undoped VO{sub 2} films. The gradual phase transition temperature window allows for precise control of the W-doped VO{sub 2} optical properties for future analog based THz devices.

  13. Modified Secret Sharing over a Single Path in VoIP with Reliable Data Delivery

    Directory of Open Access Journals (Sweden)

    K.Maheswari

    2012-01-01

    Full Text Available Abstract Voice over Internet Protocol (VoIP is a new fancy and up growing technology. A major change in telecommunication industry is VoIP. The transmission of Real time voice data is not as easy as ordinary text data. The real time voice transmission faces lot of difficulties. It suffers from packet loss, delay, quality and security. These factors will affects and degrade the performance and quality of a VoIP. This paper addresses the security and packet delivery ratio of a VoIP using modified secret sharing algorithm over a single path with reduced packet loss. The simulation results show that higher security and reduced packet loss is achieved in terms of end to end delay and packet delivery ratio. The user gets bad quality of VoIP at the receiver side. This makes the deployment of real time application a challenging task. To overcome these challenges in VoIP, several solutions have been reported already. The proper selection of active path in the routing protocol has a great impact in terms of packet delivery ratio and route discovery process. To provide end to end security between the source destination pair, the single path routing scheme is introduced.

  14. Secure Communication and VoIP Threats in Next Generation Networks

    Directory of Open Access Journals (Sweden)

    M. Hossein Ahmadzadegan

    2013-09-01

    Full Text Available VoIP services are among key issues in the Next Generation Network (NGN for the telecommunication domain. This technology is comprised of positive and negative aspects like similar emerging technologies. Nowadays, telecom operators provide call waiting, conference calling, call transfer, caller ID and other VoIP services based on NGN and all IP solution. Thus, VoIP security is now one of the issues over which many debates take place. In this paper we have decided to concentrate on vulnerability categories for VoIP services in NGN. We try to present the common security threats and vulnerabilities of VoIP services. Determining the vulnerabilities and their classification, together with the risks that this system is threatened by clarifies the ways to penetrate this system and enables administrators to solve the problems. The debate on this matter would be misleading without having full recognition of various specifications. In addition, to make the importance of identifying these types of vulnerabilities clear, we will classify the probability threats for VoIP.

  15. VoIP over Multiple IEEE 802.11 Wireless LANs

    CERN Document Server

    Chan, A

    2007-01-01

    Prior work indicates that 802.11 is extremely inefficient for VoIP transport. Only 12 and 60 VoIP sessions can be supported in an 802.11b and an 802.11g WLAN, respectively. This paper shows that the bad news does not stop there. When there are multiple WLANs in the vicinity of each other, the already-low VoIP capacity can be further eroded in a significant manner. For example, in a 5-by-5, 25-cell multi-WLAN network, the VoIP capacities for 802.11b and 802.11g are only 1.63 and 10.34 sessions per AP, respectively. This paper investigates several solutions to improve the VoIP capacity. Based on a conflict graph model, we propose a clique-analytical call-admission scheme, which increases the VoIP capacity by 52% and 37% in 802.11b and 802.11g respectively. If all the three orthogonal frequency channels available in 11b and 11g are used, the capacity can be nearly tripled by the call-admission scheme. This paper also proposes for the first time the use of coarse-grained time-division multiple access (CoTDMA) in ...

  16. Preparation, characterization and photocatalytic properties of Cu-loaded BiVO4

    International Nuclear Information System (INIS)

    A series of Cu-loaded BiVO4 (Cu-BiVO4) catalysts were prepared by impregnation method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS) and special surface area. The photocatalytic activities of Cu-BiVO4 catalysts for the degradation of methylene blue (MB) were found to depend largely on the Cu content and the calcination temperature. The optimum Cu loading and calcination temperature were found to be 5 at.% and 300 deg. C, respectively. The results of XPS and SEM analysis indicated that Cu, CuO in this case, was dispersed on the surface of BiVO4. The results of DRS analysis showed that the Cu-BiVO4 series catalysts had significant optical absorption in the visible region between 550 and 800 nm and found that the absorption intensity increased with the enhancement of Cu content. An efficient N-demethylation of MB using Cu-BiVO4 catalyst (5 at.% Cu content) calcined at 300 deg. C was also observed

  17. Single crystal and magnetic structures of maricite-type AgMnVO4

    Science.gov (United States)

    Ben Yahia, Hamdi; Shikano, Masahiro; Gaudin, Etienne; Avdeev, Maxim; Ling, Chris D.

    2015-01-01

    Single crystals of the ternary manganese vanadate AgMnVO4, were grown using AgVO3 flux. The structure was determined from single crystal X-ray diffraction data. The magnetic structure and properties of AgMnVO4 were characterized by magnetic susceptibility, specific heat, and low-temperature neutron powder diffraction measurements. AgMnVO4 crystallizes in the maricite-type structure with space group Pnma, a=9.5393(12), b=6.8132(9), c=5.3315(7) and Z=4. AgMnVO4 contains MnO4 chains made up of edge-sharing MnO6 octahedra, and these chains are interlinked by the VO4 and AgO4 tetrahedra. The specific heat measurements indicate a 3D-antiferromagnetic ordering at ~12.1 K and the neutron powder diffraction measurements at 5 K show that the Mn2+magnetic moments are antiferromagnetically coupled within the chains which are antiferromagnetically coupled to each other.

  18. Tailoring of the thermomechanical performance of VO2 nanowire bimorph actuators by ion implantation

    Science.gov (United States)

    Karl, H.; Peyinghaus, S. C.

    2015-12-01

    Vanadium dioxide VO2 nanowire bimorph actuators work on the basis of the large abrupt length change at the metal-insulator phase transition (MIT). A key parameter for the bimorph performance and efficiency is the bending curvature and the width of the temperature hysteresis of the MIT which is inherently large for single domain VO2 metal side coated nanowires. In this work we present single-clamped Ir side coated VO2 bimorphs which show unprecedented high bending curvatures of up to 105 m-1 and new type of side ion-implanted VO2 nanowire bimorph actuators with a nearly completely suppressed temperature hysteresis. It is assumed that ion-beam induced radiation defects in the VO2 crystal structure act as nucleation sites for the MIT. Moreover it will be shown that mechanical strain intentionally built-in during VO2 nanowire bimorph fabrication allows to direct phase transformation via a strain stabilized metastable phase and thus allows to control bending response on temperature change.

  19. Mechanochemical synthesis of nanostructured BiVO4 and investigations of related features

    International Nuclear Information System (INIS)

    Highly crystalline monoclinic bismuth vanadate (BiVO4) nanopowders with crystallite sizes less than 50 nm were obtained by mechanical milling of a stoichiometric mixture of bismuth oxide (Bi2O3) and vanadium pentoxide (V2O5). Different synthesized batches were obtained by varying the preparation times and the number of the tungsten carbide balls (BPR) while keeping constant the jar rotation speed. Annealing treatments were performed on the obtained nanopowders in order to improve the crystalline order and the BiVO4 nanoparticles surface states. Characterizations methods, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) equipped with X-ray energy dispersive spectrometer (EDS), Raman spectrometry, FTIR and UVVis diffuse reflectance techniques were used to shed light on the structure, morphologies and composition of the obtained nanopowders. Even if monoclinic BiVO4 crystalline structure was stabilized in samples after appropriate annealing, shifts of Raman peak positions after such treatments revealed the occurrence of symmetry distortions in the local structure of the monoclinic phase. -- Graphical abstract: Art Work BiVO4 Synthesis and Structures. Highlights: ? Synthesis by ball-milling of original nanostructures of BiVO4. ? Stabilizing a monoclinic BiVO4 polytype with nanoparticle sizes about 20 nm. ? Investigations of annealing effects on structures, vibration and optical features.

  20. Building a VO-compliant Radio Astronomical DAta Model for Single-dish radio telescopes (RADAMS)

    Science.gov (United States)

    Santander-Vela, Juan de Dios; Garca, Emilio; Leon, Stephane; Espigares, Victor; Ruiz, Jos Enrique; Verdes-Montenegro, Lourdes; Solano, Enrique

    2012-11-01

    The Virtual Observatory (VO) is becoming the de-facto standard for astronomical data publication. However, the number of radio astronomical archives is still low in general, and even lower is the number of radio astronomical data available through the VO. In order to facilitate the building of new radio astronomical archives, easing at the same time their interoperability with VO framework, we have developed a VO-compliant data model which provides interoperable data semantics for radio data. That model, which we call the Radio Astronomical DAta Model for Single-dish (RADAMS) has been built using standards of (and recommendations from) the International Virtual Observatory Alliance (IVOA). This article describes the RADAMS and its components, including archived entities and their relationships to VO metadata. We show that by using IVOA principles and concepts, the effort needed for both the development of the archives and their VO compatibility has been lowered, and the joint development of two radio astronomical archives have been possible. We plan to adapt RADAMS to be able to deal with interferometry data in the future.

  1. Microemulsion-mediated hydrothermal synthesis and characterization of zircon-type LaVO4 nanowires

    International Nuclear Information System (INIS)

    The zircon-type tetragonal (t-) LaVO4 nanowires were controlled synthesized by a new approach, a microemulsion-mediated hydrothermal method, in which the aqueous cores of sodium dodecyl sulfate (SDS)/cyclohexane/n-hexanol/water microemulsion were used as constrained microreactors for a controlled growth of t-LaVO4 nanocrystals under hydrothermal conditions. The microemulsion exists stably just at room temperature and not under hydrothermal conditions, in addition, the as-obtained nanowires are much larger than the microemulsion droplets, so that the microemulsion does not simply act as a template, but rather directs crystal growth into nanowires presumably by interacting with the surface of the growing crystal. A series of experimental results indicated that several experimental parameters, such as the SDS concentration, the species and content of the cosurfactant play important roles in the morphological control of the t-LaVO4 nanocrystals. Possible formation mechanism of t-LaVO4 nanowires is also discussed. - Graphical abstract: The zircon-type tetragonal (t-) LaVO4 nanowires were controlled synthesized by a microemulsion-mediated hydrothermal method, in which the aqueous cores of SDS/cyclohexane/n-hexanol/water microemulsion were used as constrained microreactors for a controlled growth of t-LaVO4 nanocrystals under hydrothermal conditions

  2. Properties of VO2 Films Sputter-Deposited from V2O5 Target

    Science.gov (United States)

    Tsai, Kuang-Yue; Chin, Tsung-Shune; Shieh, Han-Ping D.

    2003-07-01

    Rutile VO2 is a thermochromic material that exhibits a reversible metal-insulator phase transition upon thermal cycling. A new deposition process of rutile VO2 from a V2O5 target was developed using reactive oxygen instead of hydrogen. Adjusting the substrate temperature and the oxygen flow ratio changes the compositions and phases of the as-deposited films into rutile VO2 under optimum deposition conditions on the Si and thick glass substrates. Crystalline phases analyzed by X-ray diffraction shows the relationship among V4O9, V6O13, and VO2 films prepared under different deposition conditions. Analysis by AFM shows that VO2 films grown at higher substrate temperatures have larger grain size. The optical switching property of VO2 was measured at a wavelength of 1.5 ?m and transition temperature around 45C was also measured. Inhomogeneity and the strained structure of the film are suggested to be the reasons of transition temperature lower than typical reported value because the impurity in the target is too low to be detected quantatively by ICP.

  3. Formation mechanism of the VO2 polycrystalline film prepared by modified ion-beam enhanced deposition

    Science.gov (United States)

    Li, Jinhua; Yuan, Ningyi

    2004-12-01

    A new method of modified Ion Beam Enhanced Deposition (IBED) was designed to form VO2 polycrystalline film with good properties. While argon ion beam sputtered V2O5 powder target to deposit vanadium oxide film, a high current Ar+/H+ mixing beam with a high dose was implanted into the deposited film. The VO2 film with the Temperature Coefficient of Resistance (TCR) as high as 4%/K was obtained after subsequent appropriate annealing at the temperature above 500C. The formation mechanism of the IBED VO2 film was discussed as following: the damage effect of the argon ion beam implantation broken some of V-O bands; The deoxidization effect of implanted hydrogen reduced V2O5 to VO2. The mixing effect could make IBED film adhere to the substrate firmly. The doping effect of the implanted argon introduced stress in the film to decrease the phase transition temperature. The bombardment effect made the film more compact, decreased oxygen vacancy density, reduced the grain boundary width, and increased the TCR of the IBED VO2 polycrystalline films.

  4. Mechanochemical synthesis of nanostructured BiVO{sub 4} and investigations of related features

    Energy Technology Data Exchange (ETDEWEB)

    Venkatesan, R. [Nanoscience and Nanotechnology program, CINVESTAV-IPN, Zacatenco, Av IPN 2508, Col Zacatenco, D.F., C.P. 07360 (Mexico); Institute of Molecules and Materials of Le Mans (IMMM) UMR CNRS, Universite du Maine, 72085 Le Mans (France); Velumani, S., E-mail: velu@cinvestav.mx [Nanoscience and Nanotechnology program, CINVESTAV-IPN, Zacatenco, Av IPN 2508, Col Zacatenco, D.F., C.P. 07360 (Mexico); Department of Electrical Engineering (SEES), CINVESTAV-IPN, Zacatenco, Av IPN 2508, Col Zacatenco, D.F., C.P. 07360 (Mexico); Kassiba, A., E-mail: kassiba@univ-lemans.fr [Institute of Molecules and Materials of Le Mans (IMMM) UMR CNRS, Universite du Maine, 72085 Le Mans (France)

    2012-08-15

    Highly crystalline monoclinic bismuth vanadate (BiVO{sub 4}) nanopowders with crystallite sizes less than 50 nm were obtained by mechanical milling of a stoichiometric mixture of bismuth oxide (Bi{sub 2}O{sub 3}) and vanadium pentoxide (V{sub 2}O{sub 5}). Different synthesized batches were obtained by varying the preparation times and the number of the tungsten carbide balls (BPR) while keeping constant the jar rotation speed. Annealing treatments were performed on the obtained nanopowders in order to improve the crystalline order and the BiVO{sub 4} nanoparticles surface states. Characterizations methods, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) equipped with X-ray energy dispersive spectrometer (EDS), Raman spectrometry, FTIR and UV-Vis diffuse reflectance techniques were used to shed light on the structure, morphologies and composition of the obtained nanopowders. Even if monoclinic BiVO{sub 4} crystalline structure was stabilized in samples after appropriate annealing, shifts of Raman peak positions after such treatments revealed the occurrence of symmetry distortions in the local structure of the monoclinic phase. -- Graphical abstract: Art Work - BiVO{sub 4} Synthesis and Structures. Highlights: Black-Right-Pointing-Pointer Synthesis by ball-milling of original nanostructures of BiVO{sub 4}. Black-Right-Pointing-Pointer Stabilizing a monoclinic BiVO{sub 4} polytype with nanoparticle sizes about 20 nm. Black-Right-Pointing-Pointer Investigations of annealing effects on structures, vibration and optical features.

  5. Nanosheet-based BiVO4 hierarchical microspheres and their photocatalytic activity under visible light

    International Nuclear Information System (INIS)

    Hierarchical BiVO4 microspheres assembled by nanosheets were synthesized by hydrothermal process under microwave irradiation. The morphology and compositional characteristics of the BiVO4 architectures were investigated by SEM, TEM, and XRD. The possible formation mechanism for the architectures was discussed. UV-vis diffuse reflectance spectra indicated the BiVO4 hierarchical microspheres had absorption in both UV and vis light areas. The specific surface area and porosity of the BiVO4 architectures were investigated by using nitrogen adsorption and desorption isotherms. Because of the narrow bandgap and the novel micro-/nanostructure, the BiVO4 architectures show a more excellent photocatalytic activity under visible light irradiation than the BiVO4 solid microspheres and P25. Several possible reasons for the higher photocatalytic activity have been taken into consideration, namely, high specific surface area, hierarchical mesoporous structure, and quantum size effect. In addition, the photocatalyst is stable during the reaction and can be used repeatedly. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Selective synthesis of monoclinic and tetragonal phase LaVO4 nanorods via oxides-hydrothermal route

    International Nuclear Information System (INIS)

    Pure monoclinic (m-) and tetragonal (t-) LaVO4 nanorods are successfully obtained via a facile oxides-hydrothermal method, in which V2O5 and La2O3 bulk powders are directly utilized as precursors without pretreatment. It is found that ethylenediamine tetraacetic disodium salt (EDTA) is a key factor for synthesizing t-LaVO4. The as-obtained products are characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and selected area electron diffraction (SAED). The FTIR spectra of VO4 around 800 cm-1 are suggested as an effective auxiliary means to identify the crystal phase of LaVO4. UV-Visible spectra of LaVO4 nanomaterials are obvious blue shift compared with the bulk m-LaVO4 materials. The different photoluminescent properties of Eu3+ doped m- and t-LaVO4 are demonstrated. A dissolution-precipitation mechanism is mainly responsible for the anisotropic morphology and phase control evolution of the LaVO4 nanocrystals. The oxides-hydrothermal system is also applicable to prepare other pure LnVO4 (Ln3+: Nd3+, Y3+, Sm3+) and doped LnVO4 nanomaterials

  7. Un modelo simple para describir la dinmica de la biomasa del camarn nailon Heterocarpus reedi en Coquimbo, Chile A simple model for describing the biomass dynamics of the nylon shrimp Heterocarpus reedi at Coquimbo, Chile

    Directory of Open Access Journals (Sweden)

    Eduardo P. Prez

    2005-11-01

    Full Text Available RESUMEN. Entre septiembre de 1997 y agosto de 2000 se realiz un seguimiento diario de la dinmica espacial y temporal de la CPUE (tonlance-1 de camarn nailon por parte de la flota arrastrera con puerto base en Coquimbo. Se construy un modelo de remocin de biomasa modificado para explicar las variaciones temporales de la CPUE basado en los conceptos de abundancia (biomasa total poblacional y disponibilidad (biomasa que puede ser potencialmente capturada. Ambas cantidades fueron calculadas por ecuaciones, cuyas diferencias (positivas o negativas indicaron los cambios en la disponibilidad de la biomasa a travs del tiempo y el reclutamiento (magnitud y temporalidad. El modelo modificado indic dos perodos anuales de distinta longitud en la disponibilidad de biomasa al arte de pesca. Tambin indic una tasa de reduccin ms acelerada para la biomasa que para la CPUE. Los resultados pueden influir en la determinacin de la poca ptima para la realizacin de las evaluaciones directas del recurso con fines de determinar cuotas de capturaA daily record of space/time dynamics was carried out on CPUE (tontrawl-1 for the nylon shrimp trawl fishery based at Coquimbo, Chile, between September 1997 and August 2000. A modified biomass depletion model was constructed to analyze the temporal variations in CPUE based on the concepts of abundance (total population biomass and availability (potential biomass capture. Both quantities were calculated by equations whose differences (positive and negative indicated the changes in availability of biomass over time, as well as recruitmernt (magnitude and seasonality. The modified model suggested there were two periods annually, of different lengths, and different biomasses available with the fishing gear. The model also indicated a more rapid rate of reduction in biomass than did the CPUE. The results could influence the determination of the best season for carrying out direct resource evaluations aimed at determining catch quotas

  8. Un modelo simple para describir la dinmica de la biomasa del camarn nailon Heterocarpus reedi en Coquimbo, Chile / A simple model for describing the biomass dynamics of the nylon shrimp Heterocarpus reedi at Coquimbo, Chile

    Scientific Electronic Library Online (English)

    Eduardo P., Prez.

    2005-11-01

    Full Text Available RESUMEN. Entre septiembre de 1997 y agosto de 2000 se realiz un seguimiento diario de la dinmica espacial y temporal de la CPUE (tonlance-1) de camarn nailon por parte de la flota arrastrera con puerto base en Coquimbo. Se construy un modelo de remocin de biomasa modificado para explicar las v [...] ariaciones temporales de la CPUE basado en los conceptos de abundancia (biomasa total poblacional) y disponibilidad (biomasa que puede ser potencialmente capturada). Ambas cantidades fueron calculadas por ecuaciones, cuyas diferencias (positivas o negativas) indicaron los cambios en la disponibilidad de la biomasa a travs del tiempo y el reclutamiento (magnitud y temporalidad). El modelo modificado indic dos perodos anuales de distinta longitud en la disponibilidad de biomasa al arte de pesca. Tambin indic una tasa de reduccin ms acelerada para la biomasa que para la CPUE. Los resultados pueden influir en la determinacin de la poca ptima para la realizacin de las evaluaciones directas del recurso con fines de determinar cuotas de captura Abstract in english A daily record of space/time dynamics was carried out on CPUE (tontrawl-1) for the nylon shrimp trawl fishery based at Coquimbo, Chile, between September 1997 and August 2000. A modified biomass depletion model was constructed to analyze the temporal variations in CPUE based on the concepts of abun [...] dance (total population biomass) and availability (potential biomass capture). Both quantities were calculated by equations whose differences (positive and negative) indicated the changes in availability of biomass over time, as well as recruitmernt (magnitude and seasonality). The modified model suggested there were two periods annually, of different lengths, and different biomasses available with the fishing gear. The model also indicated a more rapid rate of reduction in biomass than did the CPUE. The results could influence the determination of the best season for carrying out direct resource evaluations aimed at determining catch quotas

  9. Electrochemical behavior of [(Mn(Bpy))(VO{sub 3}){sub 2}]?(H{sub 2}O){sub 1.24} and [(Mn(Bpy){sub 0.5})(VO{sub 3}){sub 2}]?(H{sub 2}O){sub 0.62} inorganicorganic Brannerites in lithium and sodium cells

    Energy Technology Data Exchange (ETDEWEB)

    Fernndez de Luis, Roberto, E-mail: roberto.fernandez@ehu.es [Departamento de Mineraloga y Petrologa, Facultad de Ciencia y Tecnologa, Universidad del Pas Vasco, UPV/EHU, Apdo. 644, E-48080 Bilbao (Spain); Ponrouch, Alexandre, E-mail: aponrouch@icmab.es [Institut de Cincia de Materials de Barcelona (CSIC) Campus UAB, E-08193, Bellaterra, Catalonia (Spain); Rosa Palacn, M., E-mail: rosa.palacin@icmab.es [Institut de Cincia de Materials de Barcelona (CSIC) Campus UAB, E-08193, Bellaterra, Catalonia (Spain); Karmele Urtiaga, M., E-mail: karmele.urtiaga@ehu.es [Departamento de Mineraloga y Petrologa, Facultad de Ciencia y Tecnologa, Universidad del Pas Vasco, UPV/EHU, Apdo. 644, E-48080 Bilbao (Spain); Arriortua, Mara I., E-mail: maribel.arriortua@ehu.es [Departamento de Mineraloga y Petrologa, Facultad de Ciencia y Tecnologa, Universidad del Pas Vasco, UPV/EHU, Apdo. 644, E-48080 Bilbao (Spain)

    2014-04-01

    The performance of MnV{sub 2}O{sub 6} (MnV) and its [(Mn(Bpy))(VO{sub 3}){sub 2}]?(H{sub 2}O){sub 1.16} (MnBpy) and [(Mn(Bpy){sub 0.5})(VO{sub 3}){sub 2}]?(H{sub 2}O){sub 0.62}(MnBpy0.5) hybrid derivative compounds was investigated against sodium and lithium counter electrodes. For MnV{sub 2}O{sub 6} stable capacities of 850 mAh/g were achieved in lithium cells, the best value reported so far. The whole capacity is ascribed to a conversion reaction in which the amorphization of the compounds takes place. No significant differences in the capacities for the inorganic compound and the hybrid ones were observed. Interestingly, the potential hysteresis decreases in the hybrid compounds. The difference between Li and Na cell capacity most probably comes from the difference of standard potential of the two redox couples Li{sup +}/Li and Na{sup +}/Na of about ca. 0.3 V leading to an incomplete conversion reaction and thus lowers capacity in the case of Na cells. The Raman and IR ex-situ experiments after cycling indicate that the bipyridine organic ligands are completely decomposed during the electrochemical testing. The IR studies in MnV inorganic and MnBpy and MnBpy0.5 hybrid electrodes after the electrochemical cycling, suggest that the SEI formation and bipyridine degradation give rise to different aliphatic compounds. - Graphical abstract: The electrochemical performance of [(Mn(Bpy))(VO{sub 3}){sub 2}]?(H{sub 2}O){sub 1.16} and [(Mn(Bpy){sub 0.5})(VO{sub 3}){sub 2}]?(H{sub 2}O){sub 0.62} against sodium and lithium counter electrodes give rise to the structural collapse of the initial compounds. The IR and Raman studies show that the Bpy organic ligand is completely decomposed during the during the electrochemical testing. However, after the amorphization stable capacities as high as 850 mAh/g for lithium cells were achieved. - Highlights: We test the lithium and sodium insertion in hybrid brannerites. Capacities as large as 850 mAh/g were obtained for the Li cells. The capacity and good cycling is ascribed to a conversion reaction of the electrodes. The Bpy molecule of the hybrid compounds is degraded during the first reduction. The decomposition products of the Bpy ligand reduce the potential hysteresis.

  10. Electrochemical behavior of [(Mn(Bpy))(VO3)2]?(H2O)1.24 and [(Mn(Bpy)0.5)(VO3)2]?(H2O)0.62 inorganicorganic Brannerites in lithium and sodium cells

    International Nuclear Information System (INIS)

    The performance of MnV2O6 (MnV) and its [(Mn(Bpy))(VO3)2]?(H2O)1.16 (MnBpy) and [(Mn(Bpy)0.5)(VO3)2]?(H2O)0.62(MnBpy0.5) hybrid derivative compounds was investigated against sodium and lithium counter electrodes. For MnV2O6 stable capacities of 850 mAh/g were achieved in lithium cells, the best value reported so far. The whole capacity is ascribed to a conversion reaction in which the amorphization of the compounds takes place. No significant differences in the capacities for the inorganic compound and the hybrid ones were observed. Interestingly, the potential hysteresis decreases in the hybrid compounds. The difference between Li and Na cell capacity most probably comes from the difference of standard potential of the two redox couples Li+/Li and Na+/Na of about ca. 0.3 V leading to an incomplete conversion reaction and thus lowers capacity in the case of Na cells. The Raman and IR ex-situ experiments after cycling indicate that the bipyridine organic ligands are completely decomposed during the electrochemical testing. The IR studies in MnV inorganic and MnBpy and MnBpy0.5 hybrid electrodes after the electrochemical cycling, suggest that the SEI formation and bipyridine degradation give rise to different aliphatic compounds. - Graphical abstract: The electrochemical performance of [(Mn(Bpy))(VO3)2]?(H2O)1.16 and [(Mn(Bpy)0.5)(VO3)2]?(H2O)0.62 against sodium and lithium counter electrodes give rise to the structural collapse of the initial compounds. The IR and Raman studies show that the Bpy organic ligand is completely decomposed during the during the electrochemical testing. However, after the amorphization stable capacities as high as 850 mAh/g for lithium cells were achieved. - Highlights: We test the lithium and sodium insertion in hybrid brannerites. Capacities as large as 850 mAh/g were obtained for the Li cells. The capacity and good cycling is ascribed to a conversion reaction of the electrodes. The Bpy molecule of the hybrid compounds is degraded during the first reduction. The decomposition products of the Bpy ligand reduce the potential hysteresis

  11. VoLTE Performance in Railway Scenarios : Investigating VoLTE as a Viable Replacement for GSM-R

    DEFF Research Database (Denmark)

    Sniady, Aleksander; Snderskov, Morten

    2015-01-01

    GSM-Railways (GSM-R) is the current standard for railway voice and data communication. GSM-R provides railway specific voice services, such as Railway Emergency Call (REC). GSM-R provides also the European Train Control System (ETCS), which offers in-cab signaling and Automatic Train Protection (ATP). Despite these features and services, GSM-R has various major shortcomings. Therefore, alternative technologies are considered to replace GSM-R and become the next generation railway mobile communication network. 3GPP Long Term Evolution (LTE) is a likely candidate for GSM-R replacement. LTE is more efficient, flexible and offers much higher capacity, which allows the railway network to provide new communication-based applications for railways. Most of the research on LTE in railways has been focused on data-based railway applications (ETCS signaling and other). Nevertheless, voice communication is still a crucial service for railways. Regardless of its advantages, LTE can only become a railway communication technology if it provides voice communication fulfilling railway requirements. This paper presents how Voice over LTE (VoLTE) can be used to build railway communication services. Examples of Railway Emergency Call and One-to-One Call are provided. Service performance, in terms of call setup times and voice transmission quality, is analyzed in simulation scenarios modelling two railway scenarios in Denmark.

  12. Influncia do estado nutricional e do VO2max nos nveis de adiponectina em homens acima de 35 anos / Influence of nutritional status and VO2max on adiponectin levels in men older than 35 years / Influencia del Estado Nutricional y del VO2max en los Niveles de Adiponectina en Hombres que superan los 35 Aos

    Scientific Electronic Library Online (English)

    Eduardo Camillo, Martinez; Macos de S Rego, Fortes; Luiz Antnio dos, Anjos.

    2011-06-01

    Full Text Available FUNDAMENTO: A adiponectina considerada importante fator na patognese das doenas cardiovasculares e metablicas, por suas propriedades antiaterognicas e antiinflamatrias. Poucos estudos, entretanto, sugerem a existncia de relao direta entre os nveis de adiponectina e os nveis de condiciona [...] mento cardiorrespiratrio e atividade fsica. OBJETIVO: Verificar a influncia do estado nutricional e do condicionamento cardiorrespiratrio nos nveis plasmticos de adiponectina em homens adultos. MTODOS: Foram avaliados 250 sujeitos, homens, todos militares da ativa do Exrcito Brasileiro (42,6 4,8 anos). Foram mensurados os nveis plasmticos de adiponectina, massa corporal, estatura, circunferncia da cintura (CC), percentual de gordura por pesagem hidrosttica e VO2max por ergoespirometria. Um questionrio foi utilizado para obter as caractersticas do treinamento fsico realizado pelos sujeitos. RESULTADOS: Na amostra, 121 (48%) sujeitos apresentaram sobrepeso e 36 (14%) eram obesos. Ainda, 66 sujeitos (27%) apresentaram percentual de gordura maior que 25% e 26.7% apresentaram CC > 94 cm. Sujeitos com sobrepeso e obesidade apresentaram valores significativamente menores de adiponectina em relao aqueles com estado nutricional normal. Sujeitos no mais alto tercil de VO2max apresentaram nveis de adiponectina mais altos que os demais. Os nveis de adiponectina estiveram positivamente correlacionados com o tempo total de treinamento fsico semanal e com o VO2max e inversamente correlacionados com os valores de massa corporal, IMC e CC. A correlao dos nveis de adiponectina e do VO2max no permaneceu significante aps controlada pelo IMC e CC. CONCLUSO: Sujeitos com melhor condicionamento cardiorrespiratrio e com estado nutricional normal parecem apresentar nveis mais saudveis de adiponectina. Abstract in spanish FUNDAMENTO: La adiponectina es considerada un importante factor en la patognesis de las enfermedades cardiovasculares y metablicas, por sus propiedades antiaterognicas y antiinflamatorias. Sin embargo, hay pocos estudios que sugieran la existencia de una relacin directa entre los niveles de adip [...] onectina y los niveles de condicionamiento cardiorrespiratorio y la actividad fsica. OBJETIVO: Verificar la influencia del estado nutricional y del condicionamiento cardiorrespiratorio en los niveles plasmticos de adiponectina en hombres adultos. MTODOS: Se evaluaron 250 individuos hombres, todos militares en activo del Ejrcito Brasileo (42.6 4.8 aos). Se midieron los niveles plasmticos de adiponectina, masa corporal, altura, circunferencia de la cintura (CC), porcentaje de grasa corporal por peso hidrosttico y condicionamiento cardiorespiratorio por ergoespirometria. Un cuestionario se us para obtener las caractersticas del entrenamiento fsico realizado por los individuos. RESULTADOS: En la muestra, 121 (48%), de los individuos presentaron sobrepeso y 36 (14%) eran obesos. Adems, 66 individuos (27%), presentaron un porcentaje de grasa corporal mayor que el 25%, y el 26,7% presentaron CC > 94 cm. Los individuos con sobrepeso y obesidad presentaron valores significativamente menores de adiponectina con relacin a los que tenan un estado nutricional normal. Los individuos con el ms elevado tercil de condicionamiento cardiorespiratorio, presentaron niveles de adiponectina ms altos que los dems. Los niveles de adiponectina quedaron positivamente correlacionados con el tiempo total de entrenamiento fsico semanal y con el condicionamiento cardiorespiratorio, e inversamente correlacionados con los valores de masa corporal, IMC y CC. La correlacin de los niveles de adiponectina y del condicionamiento cardiorespiratorio no permanecieron significativos despus del control del IMC y CC. CONCLUSIN: Los individuos con un mejor condicionamiento cardiorrespiratorio y con un estado nutricional normal parecen presentar niveles ms sanos de adiponectina. Abstract in english BACKGROUND: Adiponectin is consid

  13. Anlisis de la biomasa de races en diferentes tipos de bosques: Avances en la evaluacin de Pinus radiata en Chile Root biomass analysis in different forest types: research advances in the Chilean radiata pine forest

    OpenAIRE

    JAVIER GUERRA C; JORGE GAYOSO A; JUAN SCHLATTER V; ROBERTO NESPOLO R

    2005-01-01

    Se evalu la biomasa de races en la especie Pinus radiata (D. Don) en dos condiciones de sitio diferentes en Chile central, utilizando el ndice raz/vstago (proporcin de races respecto de la biomasa area). Adems, se analiz literatura referida a la proporcin de sistemas radicales con el propsito de inferir el efecto de especies y medio ambiente sobre el desarrollo de races. Se cosecharon 27 individuos de Pinus radiata de diferentes edades en un rango de 3 hasta 23 aos, 13 individuo...

  14. LA SUSTITUCIÓN DE LA SABANA NATIVA POR PLANTACIONES DE PINO Y LA VARIABILIDAD TEMPORAL EN LA BIOMASA MICROBIANA Y LA MINERALIZACIÓN DEL CARBONO Y NITRÓGENO EN EL SUELO

    Directory of Open Access Journals (Sweden)

    Yrma G\\u00F3mez

    2010-01-01

    biomasa microbiana presente en la plantación de pino, así como la menor actividad ineralizadora del C y el N en esta plantación, sugieren, que una mayor preservación de estos nutrientes ocurre en pinares; lo cual favorece la calidad del suelo. La dinámica temporal de la biomasa microbiana en la sabana nativa y en la plantación de pino no está acoplada a la variación temporal de la mineralización del C y el N de estos sistemas.

  15. In situ high-pressure synchrotron x-ray diffraction study of CeVO[subscript 4] and TbVO[subscript 4] up to 50 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Errandonea, D.; Kumar, R.S.; Achary, S.N.; Tyagi, A.K. (UNLV); (Valencia); (BARC)

    2012-02-07

    Room-temperature angle-dispersive x-ray diffraction measurements on zircon-type TbVO{sub 4} and CeVO{sub 4} were performed in a diamond-anvil cell up to 50 GPa using neon as a pressure-transmitting medium. In TbVO{sub 4}, we found at 6.4 GPa evidence of a nonreversible pressure-induced structural phase transition from zircon to a scheelite-type structure. A second transition to an M-fergusonite-type structure was found at 33.9 GPa, which is reversible. Zircon-type CeVO{sub 4} exhibits two pressure-induced transitions: first, an irreversible transition to a monazite-type structure at 5.6 GPa and, second, at 14.7 GPa, a reversible transition to an orthorhombic structure. No additional phase transitions or evidences of chemical decomposition are found in the experiments. The equations of state and axial compressibility for the different phases are also determined. Finally, the sequence of structural transitions and the compressibilities are discussed in comparison with other orhtovanadates and the influence of nonhydrostaticity commented.

  16. In situ high-pressure synchrotron x-ray diffraction study of CeVO4 and TbVO4 up to 50 GPa

    CERN Document Server

    Errandonea, D; Achary, S N; Tyagi, A K; 10.1103/PhysRevB.84.024111

    2012-01-01

    Room temperature angle-dispersive x-ray diffraction measurements on zircon-type TbVO4 and CeVO4 were performed in a diamond-anvil cell up to 50 GPa using neon as pressure-transmitting medium. In TbVO4 we found at 6.4 GPa evidence of a non-reversible pressure-induced structural phase transition from zircon to a scheelite-type structure. A second transition to an M-fergusonite-type structure was found at 33.9 GPa, which is reversible. Zircon-type CeVO4 exhibits two pressure-induced transitions. First an irreversible transition to a monazite-type structure at 5.6 GPa and second at 14.7 GPa a reversible transition to an orthorhombic structure. No additional phase transitions or evidences of chemical decomposition are found in the experiments. The equations of state and axial compressibility for the different phases are also determined. Finally, the sequence of structural transitions and the compressibilities are discussed in comparison with other orhtovanadates and the influence of non-hydrostaticity commented.

  17. Li(+) intercalation in isostructural Li2VO3 and Li2VO2F with O(2-) and mixed O(2-)/F(-) anions.

    Science.gov (United States)

    Chen, Ruiyong; Ren, Shuhua; Yavuz, Murat; Guda, Alexander A; Shapovalov, Viktor; Witter, Raiker; Fichtner, Maximilian; Hahn, Horst

    2015-07-14

    Mixed-anion materials for Li-ion batteries have been attracting attention in view of their tunable electrochemical properties. Herein, we compare two isostructural (Fm3?m) model intercalation materials Li2VO3 and Li2VO2F with O(2-) and mixed O(2-)/F(-) anions, respectively. Synchrotron X-ray diffraction and pair distribution function data confirm large structural similarity over long-range and at the atomic scale for these materials. However, they show distinct electrochemical properties and kinetic behaviour arising from the different anion environments and the consequent difference in cationic electrostatic repulsion. In comparison with Li2VO3 with an active V(4+/5+) redox reaction, the material Li2VO2F with oxofluoro anions and the partial activity of V(3+/5+) redox reaction favor higher theoretical capacity (460 mA h g(-1)vs. 230 mA h g(-1)), higher voltage (2.5 V vs. 2.2 V), lower polarization (0.1 V vs. 0.3 V) and faster Li(+) chemical diffusion (?10(-9) cm(2) s(-1)vs. ?10(-11) cm(2) s(-1)). This work not only provides insights into the understanding of anion chemistry, but also suggests the rational design of new mixed-anion battery materials. PMID:26073634

  18. Coupling effect between the structure and surface characteristics of electrospun carbon nanofibres on the electrochemical activity towards the VO2(+)/VO(2+) redox couple.

    Science.gov (United States)

    Wei, Guanjie; Gao, Zhenguo; Wei, Zengfu; Fan, Xinzhuang; Liu, Jianguo; Yan, Chuanwei

    2015-08-21

    In order to investigate the structure-function relationship of electrospun carbon nanofibres (ECNFs), polyacrylonitrile (PAN)-based electrospun carbon webs (ECWs) have been developed, consisting of ECNFs carbonized over the temperature range of 1000-1500 C in a nitrogen atmosphere. The surface morphology, microstructure, composition, electrical conductivity and hydrophilicity of the ECNFs have been characterized. The electrochemical activity of the ECNFs towards the VO2(+)/VO(2+) redox reaction has been measured by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It is worth noting that the electrochemical performance of the ECNFs decreases firstly and then rises gradually with the increase in carbonization temperature, and a carbonization temperature of about 1300 C is the turning point. This unusual phenomenon might be attributed to the coupling effect between the surface and structure characteristics of the ECNFs towards the VO2(+)/VO(2+) redox couple. The surface composition plays a leading role in the electrochemical activity of ECNFs carbonized over the temperature range of 1000-1300 C; however, the edge planes of graphite crystallites which form during the high temperature range from 1300-1500 C then become the dominant factor. Therefore, the electrochemical activity decreases with the reduction of functional groups on the surface from carbonization at 1000-1300 C, and then increases with the addition of the edge planes of graphite crystallites from carbonization at 1300-1500 C. PMID:26194622

  19. Synthesis, characterization and catalytic activity of two novel cis - dioxovanadium(V) complexes: [VO{sub 2}(L)] and [VO{sub 2}(HLox)

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Natalia M.L.; Chacon, Eluzir P.; Resende, Jackson A.L.C.; Carneiro, Jose Walkimar de M.; Lanznaster, Mauricio, E-mail: mlanz@vm.uff.b [Universidade Federal Fluminense (IQ/UFF), Niteroi, RJ (Brazil). Inst. de Quimica; Pinheiro, Carlos B. [Universidade Federal de Minas Gerais (DF/UFMG), Belo Horizonte (Brazil). Dept. de Fisica; Fernandez, Tatiana L.; Scarpellini, Marciela [Universidade Federal do Rio de Janeiro (IQ/UFRJ), RJ (Brazil). Inst. de Quimica

    2011-07-01

    Two novel complexes, [VO{sub 2}(L)] (1) and [VO{sub 2}(HLox)] (2), were synthesized and characterized by IV, UV-Vis and NMR spectroscopy, cyclic voltammetry, elemental analysis and X-ray diffraction. The synthesis of a new ligand, H{sub 2}Lox, is also described. Complexes 1 and 2 were obtained by the reaction of [VO(acac){sub 2}] with the ligands HL and H{sub 2}Lox, respectively. Alternatively, 2 was also obtained by the reaction of HL with [VO(acac)2] in the presence of hydroxylamine, and by the reaction of 1 with hydroxylamine. Crystallographic data show that complexes 1 and 2 have similar molecular structures, in which the cis-dioxovanadium(V) center is coordinated to L- or HLox{sup -}, respectively, in a distorted octahedral environment. The catalytic activity of these compounds towards cyclohexane oxidation was evaluated using H{sub 2}O{sub 2} and t-BuOOH as oxidants. Both complexes presented > 70% selectivity for cyclohexylhydroperoxide formation. B3LYP/6.31G(d) calculations were used to confirm the geometry and to help assign the electronic spectra. (author)

  20. Equaes para a previso da potncia aerbia (VO2) de jovens adultos brasileiros / Equations for predicting aerobic power (VO2) of young Brazilian adults

    Scientific Electronic Library Online (English)

    Paula, Magrani; Fernando Augusto Monteiro Saboia, Pompeu.

    2010-06-01

    Full Text Available FUNDAMENTO: O VO2 pode ser previsto, com base em parmetros antropomtricos e fisiolgicos, para determinadas populaes. OBJETIVO: Propor modelos preditivos do VO2 submximo e mximo para jovens adultos brasileiros. MTODOS: Os 137 voluntrios (92 homens) foram submetidos ao teste progressivo de es [...] foro mximo (GXT) no ciclo ergmetro (Monark, Br). Medidas de trocas gasosas e ventilatrias foram realizadas em circuito aberto (Aerosport TEEM 100, EUA). Em outro grupo, 13 voluntrios foram submetidos ao GXT e a um teste de onda quadrada (SWT), para avaliar a validade externa das frmulas do ACSM, de Neder et al e do nomograma de strand-Ryhming. Adotou-se o delineamento experimental de validao cruzada e o nvel de significncia de p Abstract in english BACKGROUND: VO2 may be predicted with base on anthropometric and physiological parameters for determined populations. OBJECTIVE: To propose models for submaximal and maximal VO2 prediction in young Brazilian adults. METHODS: A total of 137 volunteers (92 men) underwent graded maximal exercise test ( [...] GXT) in a cycle ergometer (MonarkTM, Br). Gas exchange and respiratory measurements were performed in an open circuit (AerosportTM TEEM 100, USA). In another group, 13 volunteers underwent GXT and a square wave test (SWT) in order to evaluate the external validity of Neder et al's formula, ACSM's formula, and of strand-Ryhming nomogram. The study design chosen was a cross-validation and the significance level was set at p

  1. Efecto del estrs hdrico simulado y la inoculacin con esporas de Glomus mosseae sobre el crecimiento y la particin de biomasa en avena

    Directory of Open Access Journals (Sweden)

    M. F. Ruscitti

    2007-01-01

    Full Text Available El estrs hdrico limita el rendimiento de las plantas. La micorriza favorece el crecimiento y confiere resistencia a la sequa. El objetivo de este trabajo fue estudiar el efecto del estrs hdrico moderado sobre la micorrizacin, el crecimiento y la particin de biomasa en plantas de avena (Avena sativa L. inoculadas con esporas de Glomus mosseae, a diferentes profundidades. Se sembr avena en sustrato estril sin esporas y con 100 esporas a 4, 8 12 cm de profundidad. La mitad de las plantas se sometieron a estrs moderado. Se determin: rea foliar, peso seco de parte area y raz, porcentaje de colonizacin y dependencia micorrcica. Despus de 60 das de la siembra, el porcentaje de colonizacin en las plantas regadas e inoculadas a 4 y 8 cm de profundidad y en las estresadas, a 4 cm de profundidad, fue de 25%, mientras que en el resto de los tratamientos fue significativamente menor. La biomasa seca area y de raz fue significativamente mayor en las plantas estresadas inoculadas, a 8 y a 12 cm de profundidad, comparadas con las del tratamiento testigo. La arquitectura de las races estresadas se modific con la inoculacin: mostraron una menor longitud y un aumento significativo de las races laterales. Las plantas estresadas presentaron mayor dependencia micorrcica, comparadas con las no estresadas. Segn estos resultados, la inoculacin con esporas de G. mosseae fue una estrategia favorable para soportar situaciones de estrs hdrico y la ubicacin del inculo fue un factor determinante en la respuesta de la planta.

  2. Evaluacin agronmica y nutricional del pasto Ryegrass perenne tetraploide (Lolium perenne producido en lecheras de las zonas altas de Costa Rica. I. Produccin de biomasa y fenologa

    Directory of Open Access Journals (Sweden)

    Luis Villalobos

    2010-01-01

    3090 msnm, provincia de Cartago. La disponibilidad de materia seca pre y pos-pastoreo, el aprovechamiento por hectrea y su porcentaje de utilizacin promedio para todas las fincas fueron 4110, 2276 y 1833 kg.ha-1 por corte y 44,82%, respectivamente. La edad fenolgica y la relacin hoja: tallo promedio de las pasturas de ryegrass perenne fueron 2,84 hojas verdes por rebrote, 56:44. Asimismo, la composicin promedio de la pradera fue 76,09% ryegrass, 13,76% otras gramneas (principalmente pasto kikuyo, 6,02% trbol, 1,25% malezas y 2,88% material senescente, respectivamente. La mayor produccin de biomasa durante marzo y abril puede conservarse para utilizarse durante las pocas crticas de disponibilidad de forraje o cuando por razones climatolgicas se reduce el nmero de horas efectivas de pastoreo. La evaluacin de la edad fenolgica en que se pastorea el pasto ryegrass perenne, indica que las fincas en la zona de estudio utilizan esta gramnea en un estado en el que sus reservas de carbohidratos se han recuperado, lo que permite obtener una produccin de biomasa y valor nutricional adecuados para satisfacer las necesidades del ganado lechero de la zona.

  3. Efectos de vinazas sobre bacterias rizosfricas y en la actividad-CO2 y biomasa-C microbiana de un suelo Pachic Haplustoll

    Directory of Open Access Journals (Sweden)

    Miriam Rosero G

    2013-04-01

    Full Text Available En condiciones de casa de malla de la Universidad Nacional de Colombia sede Palmira se estudi los efectos de la aplicacin de vinaza, un subproducto de la industria de alcohol carburante, sobre las bacterias rizosfricas Pseudomonas fluorescens y Bacillus subtilis promotoras de crecimiento, la actividad-CO2, biomasa microbiana-C y el cociente metablico-qCO2 en un suelo Pachic Haplustoll y su relacin con el rendimiento de habichuela (Phaseolus vulgaris L.. Se utiliz un diseo completamente al azar con siete tratamientos y cinco repeticiones. Los tratamientos se seleccionaron con base en los requerimientos de K del cultivo (150 kg/ha K2O utilizando como fuentes KCl y vinaza solos y en mezclas. Los tratamientos evaluados y la poca de muestreo influyeron (P < 0.05 en la actividad y biomasa microbiana. Los menores valores de estas variables se presentaron en la poca de floracin del cultivo cuando la demanda de nutrientes es alta. La mezcla en partes iguales de vinaza y KCl favorece la mayor produccin de habichuela sin afectar la actividad microbiana; el cociente metablico indic estabilidad del sistema en el tiempo y las bacterias rizosfricas presentaron el mejor crecimiento en la mezcla 75% de potasio como vinaza y 25% como KCl.

  4. Hydrogen-doping induced reduction in the phase transition temperature of VO2: a first-principles study.

    Science.gov (United States)

    Cui, Yuanyuan; Shi, Siqi; Chen, Lanli; Luo, Hongjie; Gao, Yanfeng

    2015-08-28

    VO2 is a promising thermochromic material that can intelligently control the transmittance of sunlight in the near-infrared region in response to temperature change, although the high phase transition temperature (Tc) of 340 K restricts its wide application. Our first-principles calculations show that hydrogen is an efficient dopant which can stabilize the metallic VO2 phase at ambient temperature through reducing Tc by 38 K/at% H. The reduction in Tc is coupled with the changes in atomic and electronic structures, i.e., the V-V chains feature the dimerization characteristics in H-doped VO2(R) and the V-O bonds become less ionic due to the formation of a typical H-O covalent bond. In addition, hydrogen-doped VO2 is more sensitive to external strain as compared with pure VO2, implying that Tc can be further regulated through a combination of H-doping and strain. PMID:26214593

  5. Selective synthesis and visible-light photocatalytic activities of BiVO4 with different crystalline phases

    International Nuclear Information System (INIS)

    Tetragonal and monoclinic bismuth vanadate (BiVO4) powders were selectively synthesized by aqueous processes. The characterizations of the as-prepared BiVO4 powders were carried out by X-ray diffraction, nitrogen adsorption, scanning electron microscopy and UV-vis diffuse reflectance spectroscopy. The photocatalytic activities of different BiVO4 samples were determined by degradation of methylene blue solution under visible-light irradiation (? > 420 nm) and compared with that of TiO2 (Degussa P25). The band gaps of the as-prepared BiVO4 were determined from UV-vis diffuse reflectance spectra. It was found that monoclinic BiVO4 with a band gap of 2.34 eV showed higher photocatalytic activity than that of tetragonal BiVO4 with a band gap of 3.11 eV

  6. Effect of inhomogeneties and substrate on the dynamics of the metal-insulator transition in VO$_2$ thin films

    CERN Document Server

    Rodriguez-Vega, M; Radue, E; Kittiwatanakul, S; Lu, J; Wolf, S A; Lukaszew, R A; Novikova, I; Rossi, E

    2015-01-01

    We study the thermal relaxation dynamics of VO$_2$ films after the ultrafast photo-induced metal-insulator transition for two VO$_2$ film samples grown on Al$_2$O$_3$ and TiO$_2$ substrates. We find two orders of magnitude difference in the recovery time (a few ns for the VO$_2$/Al$_2$O$_3$ sample vs. hundreds of ns for the VO$_2$/TiO$_2$ sample). We present a theoretical model that accurately describes the MIT thermal properties and interpret the experimental measurements. We obtain quantitative results that show how the microstructure of the VO$_2$ film and the thermal conductivity of the interface between the VO$_2$ film and the substrate affect long time-scale recovery dynamics. We also obtain a simple analytic relationship between the recovery time-scale and some of the film parameters.

  7. VoIP attacks detection engine based on neural network

    Science.gov (United States)

    Safarik, Jakub; Slachta, Jiri

    2015-05-01

    The security is crucial for any system nowadays, especially communications. One of the most successful protocols in the field of communication over IP networks is Session Initiation Protocol. It is an open-source project used by different kinds of applications, both open-source and proprietary. High penetration and text-based principle made SIP number one target in IP telephony infrastructure, so security of SIP server is essential. To keep up with hackers and to detect potential malicious attacks, security administrator needs to monitor and evaluate SIP traffic in the network. But monitoring and following evaluation could easily overwhelm the security administrator in networks, typically in networks with a number of SIP servers, users and logically or geographically separated networks. The proposed solution lies in automatic attack detection systems. The article covers detection of VoIP attacks through a distributed network of nodes. Then the gathered data analyze aggregation server with artificial neural network. Artificial neural network means multilayer perceptron network trained with a set of collected attacks. Attack data could also be preprocessed and verified with a self-organizing map. The source data is detected by distributed network of detection nodes. Each node contains a honeypot application and traffic monitoring mechanism. Aggregation of data from each node creates an input for neural networks. The automatic classification on a centralized server with low false positive detection reduce the cost of attack detection resources. The detection system uses modular design for easy deployment in final infrastructure. The centralized server collects and process detected traffic. It also maintains all detection nodes.

  8. Influência do estado nutricional e do VO2max nos níveis de adiponectina em homens acima de 35 anos

    Directory of Open Access Journals (Sweden)

    Eduardo Camillo Martinez

    2011-06-01

    Full Text Available FUNDAMENTO: A adiponectina é considerada importante fator na patogênese das doenças cardiovasculares e metabólicas, por suas propriedades antiaterogênicas e antiinflamatórias. Poucos estudos, entretanto, sugerem a existência de relação direta entre os níveis de adiponectina e os níveis de condicionamento cardiorrespiratório e atividade física. OBJETIVO: Verificar a influência do estado nutricional e do condicionamento cardiorrespiratório nos níveis plasmáticos de adiponectina em homens adultos. MÉTODOS: Foram avaliados 250 sujeitos, homens, todos militares da ativa do Exército Brasileiro (42,6 ± 4,8 anos. Foram mensurados os níveis plasmáticos de adiponectina, massa corporal, estatura, circunferência da cintura (CC, percentual de gordura por pesagem hidrostática e VO2max por ergoespirometria. Um questionário foi utilizado para obter as características do treinamento físico realizado pelos sujeitos. RESULTADOS: Na amostra, 121 (48% sujeitos apresentaram sobrepeso e 36 (14% eram obesos. Ainda, 66 sujeitos (27% apresentaram percentual de gordura maior que 25% e 26.7% apresentaram CC > 94 cm. Sujeitos com sobrepeso e obesidade apresentaram valores significativamente menores de adiponectina em relação aqueles com estado nutricional normal. Sujeitos no mais alto tercil de VO2max apresentaram níveis de adiponectina mais altos que os demais. Os níveis de adiponectina estiveram positivamente correlacionados com o tempo total de treinamento físico semanal e com o VO2max e inversamente correlacionados com os valores de massa corporal, IMC e CC. A correlação dos níveis de adiponectina e do VO2max não permaneceu significante após controlada pelo IMC e CC. CONCLUSÃO: Sujeitos com melhor condicionamento cardiorrespiratório e com estado nutricional normal parecem apresentar níveis mais saudáveis de adiponectina.

  9. Structural, photophysical and photocatalytic properties of novel Bi{sub 2}AlVO{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Luan Jingfei, E-mail: jfluan@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Zhao Wei; Feng Jingwei [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Cai Hongling [National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Zheng Zheng; Pan Bingcai [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Wu Xiaoshan [National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Zou Zhigang [Eco-Materials and Renewable Energy Research Center, Nanjing University, Nanjing 210093 (China); Li Yongmei [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Tongji University, Shanghai (China)

    2009-05-30

    Bi{sub 2}AlVO{sub 7} was prepared by solid-state reaction technique for the first time and the structural and photocatalytic properties of Bi{sub 2}AlVO{sub 7} and Bi{sub 2}InTaO{sub 7} were investigated. The results showed that Bi{sub 2}AlVO{sub 7} crystallized in the tetragonal crystal system with space group I4/mmm. In addition, the band gaps of Bi{sub 2}AlVO{sub 7} and Bi{sub 2}InTaO{sub 7} were estimated to be about 2.06 and 2.81 eV. The photocatalytic degradation of aqueous methylene blue (MB) dye with Bi{sub 2}AlVO{sub 7} or Bi{sub 2}InTaO{sub 7} as catalyst was investigated under visible light irradiation. Bi{sub 2}AlVO{sub 7} showed higher photocatalytic activity compared with Bi{sub 2}InTaO{sub 7} for photocatalytic degradation of MB under visible light irradiation. Complete removal of aqueous MB dye was realized after visible light irradiation for 160 min with Bi{sub 2}AlVO{sub 7} as the photocatalyst. The reduction of the total organic carbon (TOC) and the formation of inorganic products, SO{sub 4}{sup 2-} and NO{sub 3}{sup -} revealed the continuous mineralization of aqueous MB dye during the photocatalytic process. The possible photocatalytic degradation pathway of aqueous MB dye was revealed under visible light irradiation.

  10. Consumo Mximo de Oxgeno (Vo2max) para predecir riesgos Postoperatorios en Ciruga Abdominal Electiva

    Scientific Electronic Library Online (English)

    GA, Cabezas; LM, Melen; HE, Torrealba.

    2001-07-01

    Full Text Available Cuando el consumo mximo de oxgeno (VO2max), se encuentra por debajo de cierto valor umbral (1 l/min o menos) los riesgos de complicaciones posoperatorias aumentan en pacientes sometidos a ciruga torcica. Esta relacin no ha sido bien documentada en pacientes sometidos a ciruga abdominal. Realiz [...] amos un estudio prospectivo de tipo descriptivo sobre la capacidad que tiene el VO2max para predecir complicaciones posoperatorias, en 37 pacientes con ciruga abdominal electiva en el Hospital Vargas, Caracas y lo comparamos con la escala de medicin de riesgo general, ASA y el Indice multifactorial de Goldman III. A todos los pacientes se les practic evaluacin clnica pre y posoperatoria y los exmenes paraclnicos requeridos. Las complicaciones fueron definidas previamente y los datos obtenidos, de exmenes clnicos diarios y de las historias: quirrgicas, de anestesiologa y del servicio. El VO2max fue obtenido con el mtodo indirecto escalonado de Maneroet al validado en una poblacin latinoamericana mediante mediciones directas de VO2max y es sencillo y de bajo costo. Asigna tres cargas sucesivas de trabajo sub mximo ( Abstract in english It has been shown a relationship between maximal oxygen uptake (VO2max), and the rise of postoperative complications in thoracic surgery but that relationship has not been well studied in abdominal surgery. We undertaken a prospective, descriptive study to define the VO2max capacity to predict post [...] surgical complications in 37 patients who underwent elective abdominal surgery at the Vargas, Hospital of Caracas and we compared with the American Society of Anesthesiologists (ASA) score and with Multifactorial Goldman score. VO2max was calculated by using Manero et al. indirect method obtained from a Latinoamerican population. It is an easy and inexpensive method that requires to perform three progressive sub maximal work loads (

  11. Influence of inoculum on growth and retention of the biomass in anaerobic filters / Influencia del inoculo sobre el crecimiento y la retencin de biomasa en filtros anaerobios

    Scientific Electronic Library Online (English)

    Patricia, Torres-Lozada; Andrea, Prez-Vidal.

    2014-09-01

    Full Text Available En este estudio se evaluaron dos filtros anaerobios de igual configuracin en escala de laboratorio y usando cscara de coco como material de soporte, para el tratamiento de las aguas residuales del proceso de extraccin de almidn de yuca. Considerando que en el rea de estudio el inculo disponibl [...] e en cantidad suficiente es el estircol de vaca, se us este inculo solo (Reactor R1) y combinado con lodo granular en una proporcin 1:1 (Reactor R2). Se evalu la influencia del inculo sobre el desempeo de los filtros anaerobios, sobre la adaptacin de la biomasa al sustrato y sobre el crecimiento prevalente en el material de soporte. Ambos reactores mostraron potencial para el tratamiento de estas aguas residuales, con un Tiempo de Retencin Hidrulico (TRH) de aproximadamente 12 horas, Carga Orgnica Volumtrica (COV) de 7.0 kg DQO/m3*d y un ndice Buffer (IB) entre 0.20 y 0.35. El incremento hasta de 50% en la Actividad Metanognica Especfica (AME) al final del arranque en ambos reactores, confirm la adecuada adaptacin de la biomasa al sustrato como resultado del control de la capacidad buffer; adicionalmente, los mayores valores de AME en el R2 mostraron que la mezcla de estircol de vaca con lodo granular mejor la produccin de metano y la eficiencia del proceso. Se encontr que la biomasa ocluida tuvo mayor actividad que la biomasa adherida, indicando que el medio de soporte favoreci el desarrollo de una mayor proporcin de biomasa activa en los intersticios del material de soporte. Abstract in english In this study we evaluated, on bench scale, two anaerobic filters of equal configuration and using coconut shell as support material, for the treatment of the wastewater generated in cassava's starch extraction process. Considering that in the study area the inoculum available in enough quantity is [...] cow manure, this inoculum was used alone (Reactor 1) and mixed with granular sludge in a ratio of 1:1 (Reactor 2). The influence of inoculum was evaluated in the performance of the anaerobic filters as well as in the biomass adaptation to the substrate and the prevalent growth on support material. Both reactors showed potential for the treatment of this type of wastewater, with a Hydraulic Retention Time (HRT) of 12 hours, an average Organic Loading Rate (OLR) of 7.0 kg COD/m3*d and a Buffer Index (BI) that varied from 0.20 to 0.35. The increase up to 50% in the Specific Methanogenic Activity (SMA) at the end of the start-up in both reactors, confirmed the adequate biomass adaptation to the substrate as a result of the control of buffer capacity, and the higher values in the R2, showed that cow manure mixed with granular sludge improved methane production and process efficiency. It was found that the occluded biomass had greater activity than the attached one; this showed that the support material allowed the development of a greater proportion of active biomass within the interstices.

  12. Preparation, characterization and enhanced visible-light photocatalytic activities of BiPO4/BiVO4 composites

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: BiPO4/BiVO4 composites were successfully prepared by the hydrothermal method. BiPO4/BiVO4 composites exhibited broad absorption in the visible region. Visible-light photocatalytic activities of BiPO4/BiVO4 composites were enhanced. P/V molar ratio and pH value of the reaction affect photocatalytic activity. The mechanism of enhanced visible-light photocatalytic activities was discussed. - Abstract: BiPO4/BiVO4 composites with different P/V molar ratios were prepared by the hydrothermal method and the effect of pH values of hydrothermal reaction on photocatalytic activity of BiPO4/BiVO4 composite was investigated. The photocatalysts were characterized by X-ray diffraction, field emission scanning electron microscopy, energy-dispersive spectroscopy, X-ray photoelectron spectroscopy and UVvis diffuse reflectance spectroscopy. The photocatalytic property of BiPO4/BiVO4 was evaluated by photocatalytic degradation of Methylene blue under visible light irradiation. The results showed that the photocatalytic activity of the composites was much higher than that of pure BiPO4 and BiVO4. The rate constant of Methylene blue degradation over BiPO4/BiVO4 (P/V molar ratio of 5:1 and hydrothermal reaction pH value of 1.5) is 1.7 times that of pure BiVO4. The photocatalytic activity enhancement of BiPO4/BiVO4 composite is closely related to the BiVO4 functioning as a sensitizer to adsorb visible light and the heterojunction of BiPO4/BiVO4 acting as an active center for hindering the rapid recombination of electronhole pairs during the photocatalytic reaction

  13. Upconversion spectrum of Tm,Ho:GdVO4 pumped by pulse and CW laser at 800 nm

    International Nuclear Information System (INIS)

    The dif