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The requirements necessaries to the elaboration of the situation of Emergency PLans of the Nuclear Engineering Institute (IEN), Brazil, in particular, cases of radiation emergency are presented. An estimate of radiation in the laboratories of the Physic D...
2003-07-01
The objective of the present work was to establish pharmacokinetic parameters of the C Mitomycin (MMC) in vivo, comparing its kinetics of induction of polychromatic micro nucleate erythrocytes (EPGMN) with that of the gamma radiation. The used doses were of 0.75; 1.5 and 3. 0 {mu}moles/kg of MMC. It was observed that the MMC produces MN in the first cycle of cellular division and it is independent of the cytotoxic effect. This agent requires of a relatively long period of latency that is not compatible with her great reactivity, for what the pharmacokinetic values obtained in fact reflect the time that takes the processing of leisure in the DNA and the subsequent induction of ruptures that produce MN. (Author)
Study of personnel monitoring programs; Analise de programas de monitoracao individual
1996-12-31
Surveillance of several health institutions who use ionizing radiation sources, as well as data from the state of Rio Grande do Sul (Brazil) are studied concerning the use of personnel dosimeters. The results show that several institutions do not provide them and those which provide do not know how to use them 3 refs.
2006-01-01
To reach the quasi stationary work regime of a Tokamak, it is necessary to optimize the current generation by non inductive methods with the injection of radio-frequency waves (RF), such as the electron cyclotron waves, cyclotron ion, and in the inferior hybrid one. At the moment, the powers of the radiation sources are very big for what the such no-lineal effects as the ponderomotive force are very important. In the case of the electron cyclotron waves, in the mark of the lineal theory of waves propagation, using extraordinary waves (first and second harmonic), the problem of the singularity always arises in the exact resonance. One of the ways of eliminating this singularity is considering that the group of electrons under resonance conditions is big (quasi lineal theory) or introducing such non lineal effects such as the ponderomotive force. In the obtaining of the ...
2003-07-01
The expression kinetics of the adaptive response (RA) in mouse leukocytes in vivo and the minimum dose of gamma radiation that induces it was determined. The mice were exposed 0.005 or 0.02 Gy of {sup 137} Cs like adaptation and 1h later to the challenge dose (1.0 Gy), another group was only exposed at 1.0 Gy and the damage is evaluated in the DNA with the rehearsal it makes. The treatment with 0. 005 Gy didn't induce RA and 0. 02 Gy causes a similar effect to the one obtained with 0.01 Gy. The RA was show from an interval of 0.5 h being obtained the maximum expression with 5.0 h. The threshold dose to induce the RA is 0.01 Gy and in 5.0 h the biggest quantity in molecules is presented presumably that are related with the protection of the DNA. (Author) =.
1966-07-01
The effect of plastic straining on the room-temperature F and H growth curves in a {gamma}-radiation field has been analyzed. Cristal are strained after F-saturation is reached and then irradiation is continued. The new F growth curve consists of an initial fast growing stage due to additional vacancies created by deformation being turned into F centre, followed by a linear stage. Its slope is higher than that prior to straining. Also the role of straining on M centre thermal decay as well as on the F{yields}M reaction under F light, has been investigated. This reaction has been shown to preferentially occur where intense gliding has developed. (Author) 44 refs.
1996-12-31
The ionizing radiation doses received by radiological service workers who use a personal monitor are evaluated. A statistic method indicates that any worker has reached the dose limit of 50 m/Sv/year, as established in the CNEN (Comissao Nacional de Energia Nuclear - Rio de Janeiro, RJ, Brazil) - NE - 3.01 recommendation. The importance of training in radiological protection is highlighted 5 refs., 3 figs.
2007-01-01
In the production process of health care products, contamination must be considered as one of the principal hazards to be avoided. Among the developed methods for sterilization, ionizing radiation has largely been used by many sectors in health care area as it is efficient in eliminating biological contaminants of several origins. The difficulty of deploying ionizing radiation in materials of human origin, though, includes which possible alterations it might cause in human tissue. In the present work, the extension of the bio mechanical alteration generated by radiation in bone tissue was evaluated by bio mechanical methods. More specifically, we evaluated alterations to the elastic modulus, rupture tension and percentage of deformation that are thought to be a consequence of the sterilization process. As a research model, bovine femur struts obtained from the diaphysis ...
2002-07-01
The radiation damage effect was evaluated in the PPO-Toluene liquid scintillator solution. Samples containing PPO (1% w/v) diluted in toluene were prepared and irradiated at different doses, using a {sup 60} Co irradiator at 6,46 kGy.h{sup -1}. The radiation effect on the transmittance, light output and chemical modification in the PPO were evaluated before and after irradiation. The loss in transmittance at 360 nm decayed exponentially with the dose. The light output decreased as the radiation dose increased. The PPO degraded bi-exponentially with the dose, while the PPO degradation products, such as benzoic acid, benzamide and benzyl alcohol, increased with the dose. (author)
2004-01-01
The aim of this study is to determine the effects of diode laser irradiation on enamel demineralization. To achieve this goal appropriate photon absorbing substances for the laser radiation, safe laser parameters and adequate temperature measuring apparatus had to be determined. Next, the effects of diode laser and acidulated phosphate fluoride on enamel demineralization by calcium content analysis were evaluated with inductively coupled plasma atomic emission spectrometry (ICP-AES). In the first part of the study, five dyes consisting of vegetable coal diluted in five different liquids were analyzed and vegetable coal diluted in physiological solution was chosen for use as absorber. Methodologies to measure pulp chamber temperature were evaluated and modeling clay was chosen as fixture for the enamel samples held at body temperature. In the second part of the study, ...
2008-01-01
This work is a study of the possibilities of the technical applications of Computerized Tomography (CT) by using a device developed in the Radiation Technology Center (CTR), Institute for Energy and Nuclear Research (IPEN-CNEN/SP). The equipment consists of a gamma radiation source (60Co), a scintillation detector of sodium iodide doped with thallium (NaI (Tl)), a mechanical system to move the object (rotation and translation) and a computer system. This operating system has been designed and developed by the CTR-IPEN-CNEN/SP team using national resources and technology. The first validation test of the equipment was carried out using a cylindrical sample of polypropylene (phantom) with two cylindrical cavities (holes) of 5 x 25 cm (diameter and length). In these tests, the holes were filled with materials of different density (air, oil and metal), whose ...
2007-01-01
The physiological and enzymatic post-harvest characteristics of the pineapple cultivar Smooth Cayenne were evaluated after the fruits were gamma-irradiated with doses of 100 and 150 Gy and the fruits were stored for 10, 20 and 30 days at 12 deg C (+-1) and relative humidity of 85% (+-5). Physiological and enzymatic analyses were made for each storage period to evaluate the alterations resulting from the application of ionizing radiation. Control specimens showed higher values of soluble pectins, total pectins, reducing sugars, sucrose and total sugars and lower values of polyphenyloxidase and polygalacturonase enzyme activities. All the analyses indicated that storage time is a significantly influencing factor. The 100 Gy dosage and 20-day storage period presented the best results from the standpoint of maturation and conservation of the ...
1987-01-01
Genetical analysis procedures of the cobalt 60 gamma radiation effects in the induced mutations in quantitative characters of Caupi BR-1 Poty. The following characters were evaluated: day to first flower (FI), number of pods per plant (NVP), pod lenght (CMV), number of suds per pod (NSV), 100 seed wright (PCS), seed yield per plant (PSP) and seed yield per plant estimated by yield components (PSPE). The resistance of irradiated populations to cowpea aphid-borne mosaic virus (CpAMV)was also evaluated. (L.M.J.)
1997-01-01
This work develops an integrated analysis for neutron flux measurement systems using the concepts of cumulants and spectra. Its major contribution is the generalization of Campbell's theorem in the form of spectra in the frequency domain, and its application to the analysis of neutron flux measurement systems. Campbell's theorem, in its generalized form, constitutes an important tool, not only to find the nth-order frequency spectra of the radiation detector, but also in the system analysis. The radiation detector, an ionization chamber for neutrons, is modeled for cylindrical, plane and spherical geometries. The detector current pulses are characterized by a vector of random parameters, and the associated charges, statistical moments and frequency spectra of the resulting current are calculated. A computer program is developed for application of the proposed ...
2006-07-01
The objective of this work was to evaluate the change in mechanic properties and phase transformations of ferritic stainless steel tube, ASTM 268 Gr 446, applied in high temperature conditions. The work has used tubes from radiation furnaces of the PETROBRAS Xisto Industrialization Unit. The samples used for comparison were obtained from new tubes and tubes already used in furnaces. The test analyses were optical metallography, scanning electron microscopy, energy dispersive spectrometer, hardness and microhardness test and tension test. Results have shown that the new tubes presented a ferritic matrix and in old tubes were observed a great quantity of sigma phase and carbides. Along with the thickness of the tubes it was verified that the inside region presented an increase of sulfate and the outside region an increase of carbides. (author)
A compilation of reactor kinetics; Uma compilacao da cinetica de reatores
1996-07-01
This work presents a brief chronological review of the development of the analytical and numerical solutions to the nuclear reactor kinetics equations. An emphasis has been set on a qualitative description of the problem rather than on specific mathematical issues. (author)
2007-07-01
In the production process of health care products, contamination must be considered as one of the principal hazards to be avoided. Among the developed methods for sterilization, ionizing radiation has largely been used by many sectors in health care area as it is efficient in eliminating biological contaminants of several origins. The difficulty of deploying ionizing radiation in materials of human origin, though, includes which possible alterations it might cause in human tissue. In the present work, the extension of the bio mechanical alteration generated by radiation in bone tissue was evaluated by bio mechanical methods. More specifically, we evaluated alterations to the elastic modulus, rupture tension and percentage of deformation that are thought to be a consequence of the sterilization process. As a research model, bovine femur struts obtained from the diaphysis were used. The struts were frozen in a temperature of -70 deg C and irradiated with crescent doses of gamma radiation (0, 12.5, 25 e 50 kGy). During this work, a cutting system to obtain precision samples to use in such essays was developed. As results show that there is a significant different between the analyzed characteristics in the different doses of radiation. (author)
2006-01-01
Nondestructive Assay (NDA) is applied to machines and components quality tests. These elements would not have a good performance if they were conceived without concern about the mechanical project quality, used materials, manufacture processes and inspection and maintenance methodology. There are constant developments in high level of technology with the objective of guaranteeing the components quality and the good functioning of these machines, in the mechanics, naval, aeronautical, petrochemical and steel industry, energy and nuclear generation as well. The globalization in the industry lines is a fact, leading to an increase in the multinational projects and products. The following questions arise: how to assure the high quality of components and processes? How to optimize the test methods to assure that the materials do not have defects affecting the performance ...
2000-07-01
A study on the degradation of the pesticide Aldrin in the presence of titanium dioxide as a catalyst using non-concentrated solar light was carried out. The results show that the pesticide destruction follows a two phases kinetics, a fast one in the first four hours after the beginning of the solar light exposure, and a slow phase at longer periods of exposition. The final degradation rate is similar for any of the conditions tested in this study. Under the tested work conditions, the reduction on the concentration was always between 87 and 92%. The Aldrin degradation generated an increase on chloride ions concentration and a decrement of the pH of the solution. [Spanish] Se realizo el estudio de la degradacion del plaguicida Aldrin en presencia de dioxido de titanio utilizando luz solar no concentrada. Los resultados obtenidos muestran que la cinetica de desaparicion del plaguicida tiene dos fases, una rapida en las primeras 4 horas de exposicion a la luz solar y una mas lenta a tiempos mayores. El porcentaje final de degradacion es similar para todas las condiciones utilizadas en este estudio. Bajo las condiciones de trabajo probadas se observo una reduccion del nivel del plaguicida entre 87 y 92%. El seguimiento de la degradacion del plaguicida mostro un incremento en.
2003-07-01
This study was to evaluate and compare the effects of the low intensity in laser radiation among GaAlAs 780 nm and GaAlAs 660 nm. The main proposal is to verify if there is any difference of the effects or results in low intensity laser application treatment of hypersensitive dentin, keeping the same parameters, only differing in wavelength. The samples were distributed in two groups. Group A 90 cases, treated with GaAlAs 780 nm and group B irradiated with GaAlAs 660 nm with a total of 76 cases analyzed. The results of application with GaAlAs 660 nm and GaAlAs 780 nm do not differ statistically. Which means using any one of the irradiation gives the same results. However can be noted that the response of reduction of hypersensitivity is faster with the radiation of GaAlAs 780 nm, but the results after three applications is the same for both types of radiation. (author)
1995-12-31
A microcomputer program, denominated RESRAD, was presented and described as an analytical tool to perform pathway analysis and radiological risk assessment. Nine exposure pathways are implemented in the code. They are the following: external radiation; dust inhalation; inhalation of radon; and, ingestion of plant, meat, milk, water, aquatic food, and soil. The U.S. Department of Energy (US-DOE) has recommended the use of RESRAD, as a radiological risk assessment package, for completing the pathway analysis needed to derive specific soil-guidelines and to support the ALARA evaluation. Since its conception, the RESRAD code has been continuously improved and updated to accommodate comments and suggestions from its users and to incorporate new features to improve its capability and flexibility. Version 5.0 consolidates the last major RESRAD updates. The package is intentionally user-friendly and operates with a menu system from which the user can access the data input screens, run the RESRAD calculations and view the output. (author). 4 refs, 1 fig, 1 tab.
2007-07-15
The physiological and enzymatic post-harvest characteristics of the pineapple cultivar Smooth Cayenne were evaluated after the fruits were gamma-irradiated with doses of 100 and 150 Gy and the fruits were stored for 10, 20 and 30 days at 12 deg C ({+-}1) and relative humidity of 85% ({+-}5). Physiological and enzymatic analyses were made for each storage period to evaluate the alterations resulting from the application of ionizing radiation. Control specimens showed higher values of soluble pectins, total pectins, reducing sugars, sucrose and total sugars and lower values of polyphenyloxidase and polygalacturonase enzyme activities. All the analyses indicated that storage time is a significantly influencing factor. The 100 Gy dosage and 20-day storage period presented the best results from the standpoint of maturation and conservation of the fruits quality. (author)
1997-07-01
A heat transfer (condenser) of a domestic freezer was tested in a vertical channel in order to study the influence of the chimney effect in the optimization of the heat transfer coefficient. The variation of the opening of the channel, position and the heating power of the heat exchanger in the heat transfer coefficient was considered. The influence of the surface emissivity on the heat transfer by thermal radiation was studied with the heat exchanger testes without paint and with black paint. The air velocity entering the channel was measured with a hot wire anemometer. In order to evaluate the chimney effect, the heat exchanger was testes in a open ambient. This situation simulates its operational conditions when installed on the freezer system. The variables collected in the experimental procedures was gathered in the form of dimensionless parameters as Nusselt, Rayleigh, Grashof and Prandtl numbers, and dimensional parameters of the convection. The results showed that the highest heat transfer value occurred when both a specific position and a specific channel opening were used. The experiments pointed out that the radiation contribution must be considered in heat transfer calculations. The conclusions showed that different channel openings can improve the heat transfer coefficient in this heat transfer exchanger. (author)
Kinetic of the reaction between bitumen and sulphur. Cinetica della reazione tra bitume e zolfo
1996-01-01
The utilization of sulphur in bituminous binders has been tried for many years in a number of countries, mainly USA and Canada. The overall purpose of this study was to evaluate the kinetics of the reaction between elemental sulphur and bitumen, with the production of hydrogen sulfide. The work was carried out with the help of a thermo balance. It was shown that H2S evolution starts immediately after sulphur melting and that the rate of reaction is of second order
2003-07-01
The objective of this work is the study of the natural gamma radiation at the Areia Preta Beach (APB) in Guarapari, state of Espirito Santo, Brazil. The level of this radiation is dependent on the concentration of the radioactive mineral monazite in the sand. Probable risks of the exposure to gamma radiation at the APB were evaluated by the preliminary environmental risk analysis technique. For this purpose were conducted two annual sets monitoring gamma radiation in the APB every two months and so, acquired the seasonal variation of the radioactive levels. Additional/y was investigated the granulometry of the heavy mineral fraction and also carried out electronic microscopic scanning and radiometric age dating of the monazites of the APB, the mineral separation by magnetic susceptibility, and the mineralogic determination of the sediment. In order to gain a more complete picture of the seasonal variation, and, consequently, of the risk of exposure to ionizing radiation at the APB, the radiometric variation was also studied at some other beaches in the same region. The results indicate that the highest radiometric values are measured in summer and the lowest in winter. The radiometric dating of the monazites from the APB revealed the ages of 475 and 530 Ma. The Preliminary Hazard Analysis indicates a minimum risk of excessive radioactive exposition. It would take a period of approximately 870 years of a beach fully crowded to result in one case of bad consequences due to exposure to gamma radiation. (author)
1998-12-31
The objective was to show the necessity and the importance of the training and formation of the dentist in radioprotection according to the recent proposal for technical regulations `Radiological protection directrixes in Medical and Dentistry radiodiagnostic` of the Secretaria do Vigilancia Sanitaria of Ministerio da Saude (SVSMS). This regulation establishes basic standards to radioprotection in the medical and dentistry areas, including principles, limits, obligations and basic controls for the man and environment protection, versus possible improper effects caused by the use of ionizing radiation sources. An analysis of the discipline programs of the Dentistry Schools of Rio de Janeiro state indicates that they show a little or none preoccupation by the radiological protection, which was confirmed through a survey applied toward responsible professors by department or radiology service to the dentistry Schools. This work suggests the creation or adaptation of the existing disciplines introducing radioprotection and images quality in radiodiagnostic, to improve, complement and to make uniform the formation of future dentists optimizing the solution of the identified problems. (Author)
2000-01-01
Lead telluride (PbTe) films applied in devices to detect infrared radiation, were grown on silicon (100) and barium fluoride (111) substrates by Hot Wall Epitaxy (HWE). The films were investigated by X ray diffraction, to verify the crystallinity and the growth planes. Scanning electron microscopy, to observe the topography. Transmission electron microscopy, to study the films microstructure in the cross section and selected-area electron diffraction to analyse the growth directions. PbTe films grown on barium fluoride (BaF2) show good crystallinity and homogeneity, their growth is according to Frank-van der Merwe's Model. On the other hand, PbTe films grown on silicon (Si) substrate were not so crystalline and homogeneous owing to the impurities presence, great difference in the substrate and film lattice parameters and the thermal expansion ...
2005-07-01
The National Commission of Nuclear Energy (CNEN) is responsible in Brazil for the activities of licensing and control of radioactive installations in the radiotherapy medical area. The majority of these activities are developed by CNEN Co-ordination of Radioactive Installations (CORAD). One of the necessary stages for the development of licensing and control activities is the inspection of radiotherapy services (clinics and hospitals). Almost all of these inspections are carried out by CNEN Inst. of Radiation Protection and Dosimetry (IRD), through its Service of Medical Physics in Radiotherapy and Nuclear Medicine (SEFME). This work makes a survey of the main nonconformities found during ten years of inspections in radiotherapy services (1995 - 2004) and analyses the efficiency of these inspections in making the radiotherapy services develop their activities according to the norms in vigour in the country and adopt corrective actions against, at least, the nonconformities evidenced by CNEN inspectors. Additionally, it analyses the possibility of improvement and / or the optimisation of the process, through a procedure able to be unified and controlled, aiming a prompt communication to those involved in the licensing process (SEFME and CORAD) about the attendance by the radiotherapy services to the non-conformity items observed during the inspection. (author)
1978-01-01
The principal way of intake when individuals are accidentally exposed to the uranium compounds is the respiratory one. The deposition and clearance of the inhaled particles are influenced by the chemical, physical and biological characteristics of uranium. Kidney, lung and bones are the principal organs of deposition of absorbed uranium compounds, whose biological half-lives are approximately 6,62 +- 0,9 5 , 72,6 +- 2,2 and 322 +- 6 days respectively. An excretion function for the urinary pat radio toxicological urinalysis. This function is composed by three exponential terms, corresponding to the three organs of deposition. An estimation of the committed dose equivalent was carried out by utilizing: half-lives and the excreted, fraction suggested by I.C.R.F. The average excreted fraction calculated from experimental data. ...
1996-01-01
Liquid evaporation has been world-wide sanctioned in the nuclear industry as a volume reduction technique for laboratory effluents or rad wastes. This fast technique has showed efficiency for non volatile chemical elements concentration. The resulting mud is chemically stable, physically homogeneous and biologically inhert. It is common that low radiation level liquids, containing uranium undergo evaporation, although its quantity in the mud can be not the limiting factor for the final deposition. It often occurs that depending on liquids to be evaporated other chemical elements as flour or heavy metals could avoid the deposition of the mud in the environment. The proposed evaporator works with solar heating, although electric energy could be used, and allow to evaporate 50 L of liquids per day. Volume reduction factor can reach 95% and the construction cost is very low. In ...
2005-08-15
In this chapter it is described how the prospective analysis is carried on in: the trash and its transformation into energy that is made through thermal or biological processes; geothermal, where the relation with low and intermediate temperature resources will be differentiated from those of high temperature for electrical power generation; thermo-solar, that is a high temperature system for electrical power generation and low temperature systems for space heating or process heat; photovoltaic, that is the direct conversion of solar radiation into electricity; the wind energy is the advantage of the kinetic energy of the wind; the use of the biomass or its derivatives requires of transformations on the basis of processes of direct combustion; the gasification or pyrolysis to produce, either in direct form or through the production of a synthetic gas, process heat or electricity in facilities and, mini-hydro energy. [Spanish] En este capitulo se describe como es llevado el analisis prospectivo en: la basura y su transformacion en energia que se realiza a traves de procesos termicos o de procesos biologicos; la geotermia donde se distinguira la relacion con los recursos de temperatura baja e intermedia y los de alta temperatura para generacion electrica; la termosolar que es un sistema de alta temperatura para generacion electrica y sistema de baja temperatura para acondicionamiento de espacios o calor de proceso; fotovoltaico que es la conversion directa de la radiacion solar a electricidad; la energia eolica es el aprovechamiento de la energia cinetica del viento; la utilizacion de la biomasa o sus derivados requiere de transformaciones en base a procesos de combustion directa; la gasificacion o pirolisis para producir, o bien en forma directa o a traves de la produccion de un gas sintetico, calor de proceso o electricidad en instalaciones y, la minihidroenergia.
1996-09-01
During the last two decades, a remarkable progress on the technology of photovoltaic pumping systems (PVP) has been observed. The decrease in the costs of the photovoltaic module and the increase in the efficiency of photovoltaic pumping systems (generator and motor-pump) make PVP systems a good option for rural communities. Most analysis and simulations of PVP systems, utility function, assume the existence of a linear relationship between the hydraulic power and the solar collected radiation. Usually, more general relations exist between those variables. This work presents a new procedure for the analysis and simulation of PVP systems, which uses the utility function to consider the fluctuations in solar radiation, and leads to analytical solutions for PVP systems whose behavior can be represented by general functions, including linear relations as a particular case. The system analyzed considers the energy source (solar radiation) and the components of the water supply system like water source, photovoltaic array, subsystem for conversion of electric into hydraulic energy and, finally, hydraulic network. An analytical procedure to calculate absorbed solar radiation in the optical layers of the photovoltaic module was developed, substituting the conventional ray tracing method. The volume of pumped water was obtained integrating the water flow rate through time, considering the fluctuations related to the behavior of solar radiation and the minimum level of radiation necessary to produce useful energy. The mathematical properties of the utility function allow to derive analytical solutions for the integrals of water flow and hydraulic power. At the same time, we developed a spreadsheet which allows tho visualize the behavior of all variables involved in the process and offers the possibility of simulating different situations in order to maximize the amount of pumped water for any given system. The results obtained through the new procedure were compared with experiments made with a PVP systems installed in Oldenburg, Germany. The model reproduces well the experimental results. Both, estimated and experimental efficiency values of the system were lower (highest efficiency of 3.1%) than the values published in the technical reports (4 to 5%). (author)
1997-12-01
The effect of irradiation dose, temperature and periods of storage were analized on figs type Ramy (harvest in post-climateric stage) and type Exportation (harvest on climate stage). The figs were packed in carton boxes and irradiated with 0.0 and 1,5 kGy, a source of Cobalt-60, type Gammabeam-650, was utilized. After the irradiation, the samples were stored at room temperature ({+-} 22{sup 0} C) and under refrigeration {+-}8{sup 0} C). The samples were analised by physic and chemical analysis (soluble solids, pH, titulable acidity and ratio) after 3, 7, 13, 20 and 26 days of storage. The Rami showed higher soluble solids, pH and ratio, of type Exportation. The radiation dose effects caused small variations in all caracteristics. The soluble solids, pH and ratio increased with radiation dose, but titulable acidity decreased for both types of figs. It was observed an increased on soluble solids, titulable acidity and pH for Ramy and Exportation. The color was influenced by type of fig, radiation dose and storage period of storage. There was change in coler with high radiation dose. (author). 5 refs., 7 figs.
1996-12-31
The surgical treatment of gastric cancer has better long-term survival rates when performed in patients with early gastric cancer. Worse results are obtained in treatment of advanced gastric cancer. Most patients in west centers are treated in advanced stages. A great number of them go through a surgical treatment unable by itself to cure them. the frequent local recurrence caused by failure of the surgical treatment has been keeping poor survival rates in patients with advanced gastric cancer for decades. The desire of improving survival is the reason of the use of adjuvant therapies. This paper achieved the retrospective study of the influence of preoperative radiation therapy (2000 cGy) in long-term survival rates (120 months) of patients with advanced gastric cancer on stages IIIa, IIIb and IV. The possible injuries caused in the liver and kidney were observed also as well as first group was treated by surgical and radiation therapies and the second received surgical treatment only. There was no statistical difference between the two groups when sex, age, race, occurrence of other diseases, nutritional assessment, TNM stage, occurrence of obstruction or bleeding caused by tumor, surgical procedure and hepatic and renal function were considered. Survival rates and changes on hepatic and renal function were statistically compared. The results showed a statistic improvement on the long-term survival rates of stage IIIa patients treated by preoperative radiation therapy. No statistic difference was observed on hepatic or renal function between the groups. No adverse influence of radiation therapy method was detected by the used parameters. There was no statistical difference between the two groups when immediate surgical complications were considered. (author) 112 refs., 34 tabs.
2004-07-01
The aim of this study is to determine the effects of diode laser irradiation on enamel demineralization. To achieve this goal appropriate photon absorbing substances for the laser radiation, safe laser parameters and adequate temperature measuring apparatus had to be determined. Next, the effects of diode laser and acidulated phosphate fluoride on enamel demineralization by calcium content analysis were evaluated with inductively coupled plasma atomic emission spectrometry (ICP-AES). In the first part of the study, five dyes consisting of vegetable coal diluted in five different liquids were analyzed and vegetable coal diluted in physiological solution was chosen for use as absorber. Methodologies to measure pulp chamber temperature were evaluated and modeling clay was chosen as fixture for the enamel samples held at body temperature. In the second part of the study, different energy density parameters (1.8 J/cm{sup 2}, 3.7 J/cm{sup 2}, 5.6 J/cm{sup 2}, 7.4 J/cm{sup 2} and 9.3 J/cm{sup 2}) exposure times (10, 15, 20, 25 e 30 seconds) and time intervals between dye application and laser irradiation (5, 30, 60, 90 e 120 seconds) were evaluated with respect to temperature changes in the pulp chamber. The enamel morphology was analyzed by scanning electron microscopy. Acid resistance was measured using seventy five enamel specimens, divided in five groups (control, fluoride, laser, laser + fluoride and fluoride + laser). The amount of calcium lost during demineralization in lactic acid was measured by ICP-AES. The results obtained in this experiment permit the conclusion that diode laser irradiation did not increase acid resistance. When associated with fluoride, the acid resistance did not differ from the results obtained with fluoride alone. (author)
1998-01-01
The political events occurred in the last years of the 18th century, the Independence war and the reign of Fernando VII, ruined the Spanish scientific panorama, physics included. During the 19th century, the national scientific production was restricted to textbooks and popularization works. Two kinetic derivations of the law of perfect gases corresponding to a textbook and a book about steam engines from the viewpoint of thermodynamics are presented and discussed. (Author) 16 refs
1991-12-31
Ferrite recrystallization was investigated in two micro alloyed steels deformed in the inter critical range. A reference steel was also used, which had a composition of 0,06% C and 1,31% Mn. (author). 15 refs., 7 figs., 3 tabs.
1993-01-01
This work shows the analysis of the effect on growth kinetics of gamma prima phase in Inconel 713C alloy of two thermic treatments. In this study, SEM are used and the results are analyzed by means of the theory developed by Lifshitz, Slyozov and Wagner (LSW theory). The findings have revealed that with such theory it is not possible to determine if the process of growth is controlled either through diffusion or through diffusion in the interface as to the time employed in the experiment (2600 hours). The time required is approximately 10000 hours. (Author)
2008-07-01
This work is a study of the possibilities of the technical applications of Computerized Tomography (CT) by using a device developed in the Radiation Technology Center (CTR), Institute for Energy and Nuclear Research (IPEN-CNEN/SP). The equipment consists of a gamma radiation source ({sup 60}Co), a scintillation detector of sodium iodide doped with thallium (NaI (Tl)), a mechanical system to move the object (rotation and translation) and a computer system. This operating system has been designed and developed by the CTR-IPEN-CNEN/SP team using national resources and technology. The first validation test of the equipment was carried out using a cylindrical sample of polypropylene (phantom) with two cylindrical cavities (holes) of 5 x 25 cm (diameter and length). In these tests, the holes were filled with materials of different density (air, oil and metal), whose attenuation coefficients are well known. The goal of this first test was to assess the response quality of the equipment. The present report is a study comparing computerized tomography equipment CTR-IPEN-CNEN/SP which uses a source of gamma radiation ({sup 60}Co) and other equipment provided by the Department of Geosciences in the University of Texas (CTUT), which uses an X-ray source (450 kV and 3.2 mA). As a result, the images obtained and the comprehensive study of the usefulness of the equipment developed here strengthened the proposition that the development of industrial computerized tomography is an important step toward consolidating the national technology. (author)
Seasonal variability of the temperature and heat fluxes in the Gulf of Mexico
2002-04-01
Heat fluxes between the atmosphere and the sea surface in the Gulf of Mexico are computed using COADS climatology, bulk formulae, radiation estimations from satellite, and a numerical model. 9 W m{sup -}2 is the estimated mean surface heat flux into the ocean, this is higher than previous studies due to different bulk formulae and data sources. The annual cycle has an amplitude of 168 W m{sup -}2. The contribution of each term in the heat equation is computed, analyzed and compared to previous studies. A numerical model with thermodynamics is used to study the relative importance of heat advection and entrainment on the sea surface temperature. The results indicate that the entrainment is important in the winter cooling of surface waters. When entrainment, which depends on the buoyancy loss and the wind induced turbulent kinetic energy, is not included, temperatures in winter stay higher than observations, with a root mean square (RMS) difference from observations of 1.5 C. Including entrainment and detainment the RMS decreases to 1.0 C. [Spanish] Se estudian los flujos de calor entre la atmosfera y la superficie del mar en el Golfo de Mexico, utilizando los datos climatologicos de la base Comprehensive Ocean-Atmosphera Data Set (COADS), formulas empiricas, estimaciones de la radiacion mediante satelite y con la ayuda de la modelacion numerica. Para los flujos superficiales de calor se obtuvo una media de 9 W m{sup -}2. Este valor es mas alto que el de estudios previos debido a que se utilizaron distintas fuentes de datos y formulas empiricas. Para el ciclo anual se obtuvo una amplitud de 168 W m{sup -}2. Se calcula y analiza la contribucion de cada termino en la ecuacion de calor comparando los valores obtenidos con los de estudios previos. Un modelo numerico con termodinamica es utilizado para estudiar la importancia relativa de la adveccion de calor y los flujos verticales asociados al aporte de agua de la capa intermedia a la superficial. Los resultados muestran que los flujos entre capas son importantes en el enfriamiento de invierno de las aguas superficiales. Cuando estos flujos, que dependen de la perdida de flotacion y de la induccion de energia cinetica turbulenta a traves de la superficie, no son incluidos en el modelo, las temperaturas de invierno permanecen mas altas que las observadas y el error cuadratico medio es de 1.5 C, mientras que al incluirlos decrece a 1.0 C.
2008-07-01
Nowadays Brazilian oil refineries face an important challenge: to adjust their units to the processing of more aggressive crudes. The use of this kind of oil has caused an increase on corrosion on process streams in high temperatures. This study's objective is to evaluate the changes in mechanic properties and phases processing occurred in tubes from de radiation furnaces type A268/446 Tp ferritic stainless steel tubes used in conditions of high temperatures. For comparison samples of the APM/Kanthal alloy tube were examined. Hot tensile tests were performed in the studied materials evidence bodies. The evidence bodies for the hot tensile tests were extracted from the longitudinal position of the tubes and were machined with cylindrical shape with threads. There was a series of trials for each tube (at different traction speeds) at temperature of 600 deg C. With the traction test it was possible to evaluate resistance and ductility characteristics and was used to establish criteria for quality control to ensure satisfactory performance in certain applications. Data testing creep were performed in the evidence bodies taken from the longitudinal position of the tubes in constant charge form. Data testing creep were executed in the constant stress mode at various levels of temperature. Through data testing creep it was possible to predict for how long the material is good for use. Data from testing creep were treated by the method of Larson and Miller. (author)
1998-07-01
The present work consists of the dose reconstruction from internal contamination received by workers occupationally exposed to Iodine-131, along the years 1981 to 1994. The group of workers selected to perform this research work in the Instituto de Pesquisas Energeticas e Nucleares which is responsible for irradiated target processing, molecules labeling and distribution of radioactive material. The data analysis was performed using the urinalysis data, historical records of the individual workers exposure to radiation and records from the area radiation protection supervision. This information is used to estimate the main incorporation path, to establish an intake model and to estimate the retrospective effective dose. Using the urinalysis data it was verified that the workers, along the years, is subject to chronic intakes as well as acute intake of iodine-131. The results related to the contribution of each type of exposure were analysed separately and later added to obtain the total effective internal dose received by the worker annually. It was verified that the internal doses are different among the groups. The main factors that contributed for this difference were the task of the worker, local of operation and the amounts of iodine handled by each group. The estimative of the operation and the amounts of iodine handled by each group. The estimative of the dose to iodine workers have shown no significant increase of thyroid pathologies risk along the years. (author)
1992-07-01
A design methodology and to perform the simulation of flat plate solar collectors coupled with a water storage tank and operating by natural convection circulation is presented. For a given site the incident solar radiation on a tilted and previously oriented surface is determined from solar astronomy and the dally average of the monthly data of the horizontal total solar radiation. Huancayo situated in Peru (at 12.05 deg S, long. 76.18 deg W, altitude 3,312 m), is chosen as the site to be installed the solar water system, as a mean to improve the peasant's standard of life. An optimum tilt angle for a north oriented collector surface is obtained in order to have a maximum solar capture during the water. The theoretical methodology use here is based upon the ONG's paper (1976), and in attrition is considered the hot water drainage due to the dally consumption. For the sake of comparison, the calculated flowrate values are confronted with the experimental data obtained by FERNANDEZ, for a same site location (Rio de Janeiro) and are used identical dimensions for the water thermosyphon heater. Finally, the economic feasibility of the solar water system is demonstrated when it is compared with the usual immersion electric resistance boiler. For the Peruvian conditions the more adequate solar water system for a rural or domestic usage is a 1.4 m{sup 2} area solar collector (6 parallel, 15,875 mm copper tubes), 100 l capacity for the water storage tank, 33.5 mm for the connecting tubes, being of 300 mm. The height between the collector top and the bottom of the tank. (author)
1999-12-01
This paper presents a resume of the results obtained by the Copelite Project developed to create an specification for primary protection modules in telecommunication stations, suitable to any type of used protection technology whatsoever.
2008-07-01
Ionizing radiation metrology is the base to achieve reliable dose measurements in ali areas; it is also part of the framework that is established to assure radiation protection procedures in order to avoid or minimize the harmful biological effect that may be caused by ionizing radiation. A well done metrology means the use of reliable instruments that comply with standard performance requirements worldwide accepted. Those instruments are expected to be calibrated by Metrology Laboratories under well defined conditions. The International Electrotechnical Commission (IEC) in Standard 61267 established the reference radiations for medical diagnostic x-ray equipment that are recommended to be used for calibrating dosimetric systems for diagnostic dosimetry. In this work, X-ray beam qualities were established in a Calibration Laboratory and their characteristics were analyzed through the measurement of beam parameters like inherent tube filtration, beam uniformity and field size, energy spectra and peak voltage for additional filtration with 94.425 por cent and 99.999 por cent purity filters. Also, the first half-value layer and the homogeneity coefficient were measured for the three RQR 2, RQR 6 and RQR 10 IEC beam qualities and they were analyzed according to the IEC standard. Air-kerma measurements were carried out with an ionization chamber that had its reliability confirmed through repetition and reproducibility reading tests. In 50 sets of measurements the maximum standard deviation found of 10 successive readings was 0.19 %; the maximum shift of the reading mean value at a fixed geometry condition was 0.80 % with an overall standard deviation of 0.23 %. Results showed that the use of different purity filters did not cause a relevant influence on the beam energy spectra. An ionization chamber was also calibrated against a standard dosimeter in ali implemented reference radiations and the relevant sources of uncertainties were estimated. Calibration could be done with an expanded uncertainty of 1.50% for a coverage factor of 2 at a 95.45 % confidence level, mainly due to the uncertainty of 0.58% caused by the positioning set-up of the ionization chamber. (author)
Parallel TreeSPH$$bA Tool for Galaxy Formation
1999-04-02
We describe a new implementation of a parallel Tree-SPH code with the aim to simulate Galaxy Formation and Evolution. The code has been parallelized using SHMEM, a Cray proprietary library to handle communications between the 256 processors of the Silicon Graphics T3E massively parallel supercomputer hosted by the Cineca Super-computing Center (Bologna, Italy). The code combines the Smoothed Particle Hydrodynamics (SPH) method to solve hydro-dynamical equations with the popular Barnes and Hut (1986) tree-code to perform gravity calculation with a $N \\times logN$ scaling, and it is based on the scalar Tree-SPH code developed by Carraro et al (1998)[MNRAS 297, 1021]. Parallelization is achieved distributing particles along processors according to a work-load criterium. Benchmarks, in terms of load-balance and scalability, of the code are analised and critically discussed against the adiabatic collapse of an isothermal gas sphere test using $2 \\times 10^{4}$ particles on 8 processors. The code results balanced at more than 95% level. Increasing the number of processors, the load balance sligthly worsens. The deviation from perfect scalability at increasing number of processors is negligible up to 64 processors. Additionally we have incorporated radiative cooling, star formation, feed-back and an algorithm to follow the chemical enrichment of the interstellar medium.
1978-07-01
The principal way of intake when individuals are accidentally exposed to the uranium compounds is the respiratory one. The deposition and clearance of the inhaled particles are influenced by the chemical, physical and biological characteristics of uranium. Kidney, lung and bones are the principal organs of deposition of absorbed uranium compounds, whose biological half-lives are approximately 6,62 {+-} 0,9 5 , 72,6 {+-} 2,2 and 322 {+-} 6 days respectively. An excretion function for the urinary pat radio toxicological urinalysis. This function is composed by three exponential terms, corresponding to the three organs of deposition. An estimation of the committed dose equivalent was carried out by utilizing: half-lives and the excreted, fraction suggested by I.C.R.F.; the average excreted fraction calculated from experimental data; half-life in the kidney and the fraction y{sub u} (1) excreted during the first day, experimentally determined; experimental half-lives in the kidney and lung and y{sub u} (1), and finally by utilizing all parameters of the individual, obtaining therefore, through this fifth determination a more reliable value of the committed dose equivalent in function of the particular metabolism of the individual. (author)
2002-02-01
Fumagina is produced by the Capnodium fungi, a mushroom from Dothideales order, that lives associated with the yellow aphid (Monelliopsis pecanis), excreting a heavy load of a sugared substance that provides the sooty fungus development, covering, in some cases the totality, of leaves, fruits and branches surfaces. One of the big problems caused by this disease is the physic photosynthesis stuckness, reducing in 98% the active photosynthesis radiation and in 70% the net photosynthesis. This photosynthesis reduction affects the plants carbohydrate reservoirs, resulting in reduced and bad qualified crops. It was employed the Energy Dispersion X-Ray Fluorescence Technique (EDXRF) to study the fumagina disease. The measurements were realized with infected and healthy leaves of citric plants (orange and lemon trees), collected at the Farm School of the State University of Londrina, and also leaves of icsora plant from Piracicaba-SP. Through this technique it was observed a metabolic disorder related to Fe and Ca elements. By comparing the EDXRF spectra of the healthy plant leaves with the infected ones, it was verified that the concentration of Ca is higher than the concentration Fe in leaves of healthy plants, while for the leaves of plants infected with fumagina, it was observed a higher concentration of Fe. Employing EDXRF and the emission/transmission method for the matrix effect correction, samples of the citric plants were also analysed in pellet. The elements K, Ca, Ti, Mn , Fe, Cu and Zn were quantified. It was verified a higher Fe concentration in fumagina samples compared to the samples without fumagina. For all the elements of interest the minimum level of detection found was at the order of {mu}g g{sup -1}. (author)
2006-07-01
This work presents the effects of yttrium and neodymium alloying, on the hydrogen desorption kinetics of the Mg-5Al (wt.%) alloy. Mg-5Al-5Y and Mg-5Al-5Nd (wt.%) alloys were produced by induction melting. Neodymium alloying was more effective than yttrium alloying for improving hydrogen desorption rate at 573 and 673 K. However, yttrium alloying resulted in greater hydrogen release than neodymium alloying at 673 K. (author)
1998-10-01
While searching for the optimal substrate load for anaerobic toxicity assays, the inhibition caused by the propionic acid has been addressed. Lab scale experiments have been carried out to assess the effects of different loads and acid ratios. Results bad been subjected to kinetic analysis and show the degradation follows a first order kinetic, and acetic is easier to degrade than propionic acid. The optimal load for a 100 ml vial assay is composed of 158 mg COD of the 3:1:1 HAc:HPr:HBu mixture. (Author) 9 refs.
1996-12-31
The present work introduces the hot torsion stress relaxation test as a valid technique to follow kinetics of precipitation in extra low carbon steel micro alloyed with Ti, Nb and B. A discussion on the advantages and limitations of the technique is presented. Experimental results obtained, supported by Tem micrographs, are in good agreement with those reported in the literature. The effects of different deformation conditions and chemical compositions on the kinetics of precipitation are reported and discussed. (author) 20 refs., 12 figs., 2 tabs.
2002-07-01
In this work is presented a methodology which focuses the distribution of neutron absorber rods in nuclear reactor power plants, for utilizing in space kinetic calculations, principally in the cluster ejection transients of control rods. A numerical model for macroscopic constant calculations based on the knowledge of the neutron flux without the control rods is proposed, as alternative to the analytical models, based on the hypothesis of the null current on the cell super boundaries. The proposed model in this work has itself showed adequate to deal with problems with strong space dependence, once that the model showed consistence in the global average built in the analytical model. (author)
2005-07-01
The reason of decay is the indicator of stability usually used in the literature to evaluate stability of boiling water reactors, however, in the operation of this type of reactors is considered the length of boiling like an auxiliary parameter for the evaluation of stability. In this work its are studied the variation of these two indicators when modifying a given an operation parameter in a model of a thermo hydraulic channel coupled to punctual kinetics, maintaining all the other input constant variables. The parameters selected for study are the axial profile of power, the subcooling, the flow of coolant and the thermal power. The study is supplemented by means of real data of plant using the one Benchmark of Ringhals, and the results for the case of the ratio of decay its are compared with the decay reasons obtained by means of autoregression models of the local instrumentation of neutron flux. (Author)
2005-01-01
The reason of decay is the indicator of stability usually used in the literature to evaluate stability of boiling water reactors, however, in the operation of this type of reactors is considered the length of boiling like an auxiliary parameter for the evaluation of stability. In this work its are studied the variation of these two indicators when modifying a given an operation parameter in a model of a thermo hydraulic channel coupled to punctual kinetics, maintaining all the other input constant variables. The parameters selected for study are the axial profile of power, the subcooling, the flow of coolant and the thermal power. The study is supplemented by means of real data of plant using the one Benchmark of Ringhals, and the results for the case of the ratio of decay its are compared with the decay reasons obtained by means of autoregression models of the local instrumentation of ...
2004-07-01
The current work presents a mathematical model of an ascendant flow vertical reactor (riser) of a Fluid Catalytic Cracking Unit. The two-phase flow (gas-solid) and the cracking reactions are admitted one-dimensional and steady state. Mass, momentum and energy conservation equations are considered for each phase (solid and gas). A six-lump kinetic model is employed to evaluate gasoil, gasoline, GLP, fuel gas, light cycle oil and coke fractions. The model results are compared to experimental values from a pilot plant and to another model found in the literature. The results are in good agreement, showing the model has great potential. (author)
1961-01-01
The rate of the proto tropic change of benzylidene-benzylamine has been determined by using azomethine 14C-labelled in the methylenic group and measuring the distribution of activity between benzaldehyde and benzylamine obtained by hydrolysis at different reaction times. this rate has been compared with those of tautomerization of benzylidene-alpha-alkyl benzylamine and alpha-alkyl benzylidene-benzyl amines in the same experimental conditions in order to establish ethe influence of alkyl group on this reaction. (Author) 14 refs
1997-12-31
The kinetics of alkaline hydrolysis of methylparathion was studied at different temperatures (0-50 Centigrade) in the p H range of 8-12 by ultraviolet-visible absorption spectroscopy. Optimum p H and wavelength conditions were defined to carry out the simultaneous determination of methylparathion and one of its hydrolysis product, paranitrophenol, in buffered aqueous medium. Based on the experimental data and the mathematical equation of the kinetics, a rate constant (k) of first-order and an activation energy (Ea) of 9.2 Kcal/mol, were estimated. (Author) activation energy (Ea) of 9.2 Kcal/mol, were estimated. (Author)
2009-01-01
The erosive capacity of raindrops is function of mass (size) and terminal velocity. Drop mass and velocity govern the inherent erosivity of rainfall through kinetic energy. Kinetic energy is a very important property of the rainfall because it is one of the sources of energy in the process of water erosion. Vegetative canopy intercepts the raindrops and causes a variation on this rainfall kinetic energy due to modification of diameters and velocities distributions. If the height of canopy is enough, the bigger intercepted drops could achieve high velocities and their kinetic energies can increases. In this paper a quantitative evaluation of the increase of kinetic energy of intercepted drops is obtained and it is showed that this kinetic energy increases exponentially with vegetation height. (Author) 9 refs
1987-12-31
The effects of three previous microstructures (spheroid, spheroid plus coarsened and hardened and tempered) on the austenite formation temperatures under continuous heating and on isothermal transformation of austenite, have been studied for AISI 52100 steel. The hardened and tempered material had the lowest Aclb and Acle temperatures. With this condition it had been also obtained the smallest austenitic grain size and the smallest time for the austenite transformation start at the two noses of each TTT curve. These effects can be explained by the differences of distribution and composition of the previous microstructure carbides. This work discuss some practical consequences when short austenitizing times are used for hardening, as is the case of induction hardening. (author) 21 refs., 11 figs.
2007-01-01
In this work the initial results of the joining of an arrangement of 36 channels in parallel are studied to a modal neutronic kinetic model to represent the core of a BWR type reactor. The set of channels is obtained group the assemblies of that it consists the core in an arrangement of concentric rings, for later on to subdivide each ring in four parts to assign each segment to a quadrant of the core. The obtained channels are coupled to a modal kinetics model that considers the fundamental way and the first harmonic. The obtained solution represents the radial distribution and power azimuthal, the one which is feedback to the channels to update the thermohydraulic variables. The restriction that the pressure drop is same for each channel it is only imposed as initial condition, like part of the stationary state, and it is allowed that the pressure drop in the assemblies them it is different ...
2003-01-01
In this work the dynamic behavior of a consistent system in fifteen channels in parallel that represent the reactor core of a BWR type, coupled of a kinetic neutronic model in one dimension is studied by means of time series. The arrangement of channels is obtained collapsing the assemblies that it consists the core to an arrangement of channels prepared in straight lines, and it is coupled to the unidimensional solution of the neutron diffusion equation. This solution represents the radial power distribution, and initially the static solution is obtained to verify that the one modeling core is critic. The coupled set nuclear-thermal hydraulics it is solved numerically by means of a net of CPUs working in the outline teacher-slave by means of Parallel Virtual Machine (PVM), subject to the restriction that the pressure drop is equal for each channel, which is executed iterating on ...
2004-01-01
In this work an arrangement of thermohydraulic channels is presented that represent those four quadrants of a nucleus of reactor type BWR. The channels are coupled to a model of neutronic in two dimensions that allow to generate the radial profile of power of the reactor. Nevertheless that the neutronic pattern is of two dimensions, it is supplemented with axial additional information when considering the axial profiles of power for each thermo hydraulic channel. The stationary state is obtained the one it imposes as frontier condition the same pressure drop for all the channels. This condition is satisfied to iterating on the flow of coolant in each channel to equal the pressure drop in all the channels. This stationary state is perturbed later on when modifying the values for the effective sections corresponding to an it assembles. The calculation in parallel of the neutronic and ...
2000-07-01
In this work the incorporation of activation energy and frequency factor parameters proposed by R. Chen are presented in the original formulation of Randall and wilkins second order kinetics. The results concordance are compared between the calculus following the R. Chen methodology with those ones obtained by direct incorporation of the previously indicated in the Randall-Wilkins-Levy expression for a simulated thermoluminescent emission curve of two peaks with maximum peak temperature (tm): t m1=120 and t m2=190. (Author)
1984-07-01
In general the process of adsorption of phages to bacteria is considered in the bibliography as an statistical process. In this work we use an empiric expression which allows to interpret the approximation of {lambda}cI pages to E. coli C{sub 6}00 bacteria. This expression introduces some changes respect to a pure statistical description of the approximation process. (Author) 26 refs.
1999-07-01
The main purpose of the present study was to determine the lead-210, polonium-210 and lead concentrations in foods and diets. Consumption of food is generally the main route by which radionuclides can enter the human organism. Precision and accuracy of the methods developed were verifies by the analysis of reference materials from the International Atomic Energy Agency (IAEA). The method for polonium-210 analysis consisted of sample dissolution by using a microwave digester (open system) employing concentrated nitric acid and hydrogen peroxide, evaporation almost dryness, addition of hydrochloric acid, polonium deposition onto silver disc for six hours and counting by alpha spectrometry. Lead was analysed by atomic absorption technique. After sample dissolution in a microwave digester (using concentrated nitric acid and hydrogen peroxide) and dilution to 50 ml, 20{mu}l of the sample was injected in a pyrolytic graphite furnace - atomic absorption spectrophotometer equipped with Zeeman background correction. The assessment of the contaminants in foods and diets allowed to estimate the intake of these elements and for the radionuclides were also evaluated the radiation doses that the individuals selected were exposed by the food consumption. The effective dose for lead-210 by diets intake ranged from 1.3 to 4.3 {mu}Sv/year, corresponding to 25% of the resulting from polonium-210 intake. The dose due to the both natural radionuclides varied from 6.8 to 23.0 {mu}Sv/year. These values are in good agreement with the literature data. The value estimated by the United Nations Scientific Committee on Effects of Atomic Radiation (UNSCEAR, 1993) that is 60 {mu}Sv and lower than the dose of 0.02 Sv, limit established by ICRP, 1980. The lead levels found in the majority of the Brazilian foods are in good agreement with the values published by CONAT and FAO/WHO. However, some foods such as bean, potato, papaya, apple and rice present levels above of the recommended values by the Public Health Council. For diets, the total lead intakes varied between 29.1 and 574.7 {mu}g Pb/day and to some of the diets analysed, lead levels exceeded the provisional tolerable weekly intake recommended by the WHO. (author)
2004-07-01
Food borne diseases, in particular gastro-intestinal infections, represent a very large group of pathologies with a strong negative impact on the health of the population because of their widespread nature. Little consideration is given to such conditions due to the fact that their symptoms are often moderate and self-limiting. This has led to a general underestimation of their importance, and consequently to incorrect practices during the preparation and preservation of food, resulting in the frequent occurrence of outbreaks involving groups of varying numbers of consumers. Despite substantial efforts in the avoidance of contamination, an upward trend in the number of outbreaks of food borne illnesses caused by non-spore forming pathogenic bacteria are reported in many countries. Good hygienic practices can reduce the level of contamination but the most important pathogens cannot presently be eliminated from most farms, nor is it possible to eliminate them by primary processing, particularly from those foods which are sold raw. Several decontamination methods exist but the most versatile treatment among them is the ionizing radiation procedure. HACCP (Hazard Analysis and Critical Control Point) is a management system in which food safety is addressed through the analysis and control of biological, chemical, and physical hazards from raw material production, procurement and handling, to manufacturing, distribution and consumption of the finished product. For successful implementation of a HACCP plan, management must be strongly committed to the HACCP concept. A firm commitment to HACCP by top management provides company employees with a sense of the importance of producing safe food. At the same time, it has to be always emphasized that, like other intervention strategies, irradiation must be applied as part of a total sanitation program. The benefits of irradiation should never be considered as an excuse for poor quality or for poor handling and storage conditions, i.e.. as a substitute for good manufacturing practices. By adopting an HACCP based approach to food safety management, it can be clearly demonstrated that the application of a technology like food irradiation is essential for ensuring the safety of raw food stuffs. Such an intervention should be considered as a CCP (Critical Control Point) in the food chain. Therefore, the potential benefit of irradiation, which is endorsed by national and international bodies surely merits serious consideration by public health authorities, industry and consumer groups worldwide. For such, a system of HACCP and the irradiation is primordial so that the alimentary .safety is maintained processes if they are applied correctly. (author)
Thermodynamic methods of energy analysis; Metodos termodinamicos de analise energetica
1984-12-31
The thermodynamic methods of energy systems analysis, the lost work analysis and the energy method, are described. These two methods are applied to a system of utilities of an autonomous alcohol distillery. The characteristics of each method and the advantages of energy analysis in the choice of a process are shown. (author). 11 refs., 2 figs., 2 tabs
1998-01-01
This work presents an analysis of a loop operating in natural circulation regime. Experiments were done in a rectangular closed circuit in one and two-phase flows. Numerical analysis were performed initially with the CIRNAT code and afterwards with RELAP5/MOD2. The limitations of CIRNAT were studied and new developments for this code are proposed. (author)
Safety analysis in nuclear power plants; Analise de seguranca em centrais nucleares
1987-12-31
This work discusses the safety in nuclear power plants specifically in what concerns the reactor operation. The basic aspects concerning the project of a nuclear power plant are presented, as well as safety analysis and mathematical models used in the safety analysis. The risk probability is also discussed
1989-01-01
A decision-making method based on risk analysis theory and on previous fishing operation experiences at a field under study can be applied to decisions concerning whether or not interrupt a fishing job at a given moment. Examples of method application are provided. (author). 10 figs., 3 tabs., 4 refs
1999-07-01
This paper presents the risks related to the State of not following its original principles and objectives regarding the energy sector. The challenges and risks of the State with its new function as regulator, through the regulation agencies, will be analysed. A comparison between the institutional structure of the Brazilian electrical sector and other countries will be accomplished, focusing on the following aspects: competition, regulation and commercial operation. (author)
1991-12-31
An analysis of the damage on power transformer winding during occurrence of electrical transients in substations, its causes and an analysis of its occurrence situations are presented. Results of studies in the substation Ouro Preto 2, made by CEMIG (Companhia Energetica de Minas Gerais) aiming an analysis of the possibility to occur damage in transformers winding are also reported 6 refs., 8 figs., 1 tab.
1987-12-31
This work aims to describe CESP`s process of research and development of a system based in microprocessor computer to be used in the analysis of major disturbances and behaviour of the regional system. The system is fully explained as well as the future perspectives based on its utilization. The infra-structure developed for the system is also being used for other projects which are named
2006-07-01
The present work analyses the european and american experiences in the re utilization of water in refineries and to point out perspectives for the regulation of water re utilization in Brazil, by using the present management instruments of the hydraulic resources.
1996-02-01
This work presents two models for implementation of staggers for network analysis functions in real time for a control center. The methodology is described. Tests were performed in a electric power system of Campinas region, Sao Paulo sate - Southeast Brazil. Results are presented.
1987-01-01
The radiotoxicology laboratory of Nuclear and Energetic Research Institute (IPEN) has the objective of control the internal contamination of workers that handle radioactive materials, in industrial and medical sectors. This control is made through radiochemical analysis of excreta. Nowadays in this laboratory are realized occupational controls on individual, exposure to uranium, tritium, iodine, fluorine, lead compounds, for workers of IPEN and for external institutions, when solicited. (C.G.C.)
2004-01-01
Quantitative GC-FID was evaluated for analysis of methylated copaiba oils, using trans-(-)-caryophyllene or methyl copalate as external standards. Analytical curves showed good linearity and reproducibility in terms of correlation coefficients (0.9992 and 0.996, respectively) and relative standard deviation (
1992-09-01
This paper shows the results of the optimization of the process of preparation and deposition of thermionic emissive substances that are used in the oxide-cathodes which are utilized in the gun of the IEAv linear electron accelerator. (author). 5 refs., 5 figs.
1993-12-31
These works includes AC/DC load flux studies, electrical systems digital simulation, microcomputer in potential electric system planning studies, Flexible AC Transmission Systems - FACTS and voltage stability studies
1995-12-31
This work analyzes coatings used in the boxes 1 and 2 annealing line furnaces of the Companhia Siderurgica Nacional. Insulator refractory bricks from the original project are compared with thermal insulator coatings used in the annealing line 2.
1997-07-01
This paper presents a complete mathematical and computer model which allows simulating a generic hydroelectric power plant under steady state and transitory regimes, in the extensive time, and also the analysis of the oscillating flows resulting from excitation sources present in the installation, such as vortices in the suction pipe during partial load operation.
1998-04-01
The authors report a retrospective study of 107 cases of clinically proved multiple sclerosis and confirmed by magnetic resonance imaging, in a state of Brazil (Parana) which is located between the parallels 22 and 30 South. Comments are made about the age of the patients, number and location of the lesions in the brain and spinal cord. (author) 31 refs., 6 figs., 3 tabs.
1978-01-01
A short description is given of work in progress on the analysis of prestressed concrete containment vessels for nuclear reactors. Firstly,numerical analysis are described and some results shown. Secondly, a description of a microconcrete model under construction is given: forms, prestressing and loading systems and measuring devices. (Author)
1991-12-31
This work shows a comparative study of three hierarchy state estimators in electric power systems. It also showed the determinant characteristics of each estimator, verifying its applicability at the state prediction level in interconnected power systems. 3 tabs., 10 refs.
Energy analysis of Rio de Janeiro subway; Analise energetica do Metro do Rio de Janeiro
1984-12-31
In this work an energy analysis of the Subway System from Rio de Janeiro city (Metro-RJ) is made. Only the direct energy involved on the subway operation is considered. The system and the electrical network are also defined. At the end, the direct energy spent by transported passenger is determined. (author). 4 tabs
2003-07-01
This chapter presents the results of the economic potential of the natural gas cogeneration under topping regime, in the selected sectors of beverage industry, editorial and graphic industries, shopping centers, hospitals and hotels.
1988-12-31
This work describes the most common methods for potatoes irrigation presently in use in the South area of Minas Gerais State - Southeast Brazil - and calculates the diesel oil consumption in this activity. Based on that an economic analysis is performed. Electric power is presented as an alternative for diesel oil in such activity 10 refs., 2 figs., 4 tabs.
1993-12-31
This paper presents some techniques for cost analysis along the equipment`s lifetime comprising different goals such as budgetary forecast, maintenance criteria optimization, maintenance efficiency checking, new equipment and new technologies acquisition and comparative analysis between different kinds of equipment 7 refs., 7 figs., 1 tab.
2006-07-01
This paper observes the relationship among the energy use and increasing in equipment energy efficiency, from the view of demand. The paper also analyses the relationship among the energy consumption with revenue classes, and discusses some aspects of the energy conservation politics, emphasizing the importance in taking the account phenomena such as boomerang effect.
1997-12-31
This work presents the conformational analysis of some selected oxa-thio-azolidines. As the chemical properties of such compounds do not depend only upon the chemical structure, but also upon the conformational state which they may present, special emphasis is given to this phenomenon, which can elucidate the compounds properties 5 refs., 8 figs., 2 tabs.
1995-12-31
The utilization of wind power in more than 40 countries was performed following several guidelines which are analysed in this work aiming the definition of a strategy which can be applied in Brazil. A brief explanation of these strategies used abroad is provided as well as a comparative analysis of them. The outline of a Brazilian strategy is provided 37 refs., 1 tab.
1999-07-01
This work purposes the performance comparison of the types of compressors, embracing hydraulic, electromechanical, water cooler, air cooler, lubricated, exempted of oil and crankcase pressurized and not pressurized, applied in the positions of provisioning of gas natural automotive, as well as to illustrate the costs of installation, maintenance and consumption of usefulness, allowing the selection of the most applied equipment to the project. (author)
1999-07-01
The aim of the work was to present a comparative analysis between hydroelectric generation and natural gas based on integrated resource planning and sustainable development. The introduced comparative analysis considers the financial aspects; the appropriated technology; and the social, environmental and political factors. The hydroelectric option it showed more advantageous than the thermoelectric. This result was independent of the enterprise scale.
1999-01-01
The aim of the work was to present a comparative analysis between hydroelectric generation and natural gas based on integrated resource planning and sustainable development. The introduced comparative analysis considers the financial aspects. The appropriated technology. And the social, environmental and political factors. The hydroelectric option it showed more advantageous than the thermoelectric. This result was independent of the enterprise scale
1990-12-31
Exergy balance equations are applied to a thermodynamic model in order to evaluate the combustion process for diesel engines. Thermomechanical and chemical availabilities are determined as well as the irreversibility produced. Finally the model is used to analyze experimental data obtained for a single cylinder diesel engine, at full load condition. (author) 14 refs., 6 figs., 2 tabs.
1996-12-31
An algorithm which allows bone age assessment by digital radiological images was developed. For geometric parameters extraction, the phalangeal and metacarpal regions of interest are enhanced and segmented, through spatial and morphological filtering. This study is based on perimeter, length and area, from distal to proximal portions. The quantification of these parameters make possible comparison between chronological and skeletal age, using growth standard tables 3 refs., 2 figs
1996-12-31
The analysis of the results of the quality control program on radiological equipment has shown that this program has been very useful in reducing the breaking and the consequential long-interruption-periods frequently caused by technical problems 3 refs.
2002-07-01
This paper presents a study on the use of decision tree technique for analysis of alternative policies for the Brazilian petroleum sector, considering the present international perspectives and nation petroleum production, consumption and import.
1987-12-31
This work discusses the evacuation need in case of a major nuclear accident using as basic example Angra I nuclear power plant, Rio de Janeiro State, Southeast Brazil. Some technological aspects are discussed as well as the environmental impacts of such an accident 5 refs.
1984-12-31
In this paper two kind of gramineae and two kind of aquatic plants common in the Paraiba do Sul river were analysed from the heat power and chemical components point of view. It also discusses the industrial application. 3 refs., 4 figs., 4 tabs.
1996-12-31
Analysis of rejected radiographic films performed for 10 months is presented. The relationship between the most rejected exam type, the size of film which has greater number of rejection and the cause of the rejection is considered. Some other aspects such as the competence of technical people involved, troubles in the equipment, the processing of the film and the way patients are positioned are also evaluated 4 refs.
1987-12-31
The purpose of this work was to determine excellent levels of corn processing by small hammer mills. The parameters studied were: active, reactive, and total power; as well as the motor revolution velocity and the engine; as a function of different outflows. The results are presented. 7 refs., 1 fig., 1 tab.
The relationship between advanced very high resolution radiometer (AVHRR)/NOAA and thematic mapper (TM)/LANDSAT data is evaluated for estimating the contact area of the savanna and forest. This study is a contribution to the development of a multisensor a...
1999-07-01
The article introduces a methodology for data energy regional consumption consistency analysis. The work was going based on recent studies accomplished by several cited authors and boarded Brazilian matrices and Brazilian energetics regional balances. The results are compared and analyzed.
2004-01-01
The heat transport circuits of a nuclear power plant have different water chemistries, corrosion product sources, temperatures and flow rates and these parameters influence the growth and deposition of oxides with different compositions on the surfaces of the nuclear steam generator tubes. In conjunction with other compounds produced by in-situ corrosion these deposits originate the so-called 'corrosion fouling' phenomenon. One of the consequences of this process is a progressive degradation of the heat transfer capability of the steam generator tubing. The purpose of this paper was to establish the corrosion kinetics of Incoloy 800, 304L stainless steel and 516 carbon steel, alloys which are exposed in the secondary circuit of nuclear steam generator. The experiments have been carried out by static autoclavization at T= 2600 deg C and p= 5.1 MPa in aqueous solutions ...
1996-01-01
The sensitization kinetics of AISI 347 austenitic stainless steel samples, removed from a forged bar, was investigated with an electrochemical potentiokinetic reactivation method. After the solution anneal at 1140 deg C, the steel was submitted to sensitization treatments at 550 deg C, 670 deg C, 790 deg C and 910 deg C during times that varied from 1 h to 62 h. It was found that samples treated at 550 deg C, 670 deg C and 790 deg C become sensitized. The activation energy was found to be 124 kJ/mol. The observed behaviour was discussed in terms of both carbon retention in solution after the solution anneal and kinetics of carbon combination with chromium and niobium. (author)
2003-07-01
In this work a finite differences technique centered in mesh based on a cubic reduced nodal scheme type finite element to solve the equations of the kinetics 1 D that include the equations corresponding to the concentrations of precursors of delayed neutrons is described. The technique of finite elements used is that of Galerkin where so much the neutron flux as the concentrations of precursors its are spatially approached by means of a three grade polynomial. The matrices of rigidity and of mass that arise during this discretization process are numerically evaluated using the open quadrature non standard of Newton-Cotes and that of Radau respectively. The purpose of the application of these quadratures is the one of to eliminate in the global matrices the couplings among the values of the flow in points of the discretization with the consequent advantages as for the reduction of the order of the matrix associated to the discreet problem that is to solve. As for the time dependent part the classical integration scheme known as {theta} scheme is applied. After carrying out the one reordering of unknown and equations it arrives to a reduced system that it can be solved but quickly. With the McKin compute program developed its were solved three benchmark problems and those results are shown for the relative powers. (Author)
1961-07-01
The rate of the proto tropic change of benzylidene-benzylamine has been determined by using azomethine {sup 1}4C-labelled in the methylenic group and measuring the distribution of activity between benzaldehyde and benzylamine obtained by hydrolysis at different reaction times. this rate has been compared with those of tautomerization of benzylidene-{alpha}-alkyl benzylamine and {alpha}-alkyl benzylidene-benzyl amines in the same experimental conditions in order to establish ethe influence of alkyl group on this reaction. (Author) 14 refs.
2005-01-01
In the progress of the Nuclear Medicine, many protein based radiopharmaceuticals have been developed in the last years using antibodies and, more recently, biologically active natural peptides or similar synthetic peptides. In the search for agents with specificity for the target tissue in tumors detection, it was verified that small sequences of amino acids may interact with selective sites, with homogenous distribution, fast accumulation in tissues and fast blood clearance when compared to the antibodies. Among the peptides used in the diagnosis of tumors, Vasoactive Intestinal Peptide (VIP) has been studied. VIP labeled with iodine-123 is applied in the images of intestinal adenocarcinoma and endocrine tumors. The molecule of VIP contains two tyrosine residues, in the positions 10 and 22 that are, theoretically, equally susceptible to radioiodination for direct ...
2003-07-01
During the petroleum exploration and production processes, a great amount of water is produced together with the oil and the natural gas. This water needs an appropriate treatment before been discarded or reuse, due to a their great amount of organic pollutants content. Several separation processes are used in order to improve the effluent quality. In this way, the research of new adsorbent materials that present a low industrial cost has great importance. In this paper, adsorption experiments of organic pollutants using as adsorbent, the corn-cob, the powder wood and the coconut mesocarp, were accomplished. The organic effluent used in this work was simulated by a dispersion of gas in water and the experimental data were obtained through experiments in an agitated reactor. The kinetic curve was been adjusted for Michaelis-Menten equation and equilibrium isotherm modeling with Langmuir isotherm. Both model fitted well the experimental data. The obtained results show the viability of the use of the biomass as adsorbents for organic pollutants, once, with appropriate amounts of the gas/biomass, it was possible to eliminate, practically, the whole pollutant. (author)
1987-12-31
The catalytic effects of potassium carbonate on the rate of gasification of charcoal with carbon dioxide has been investigated by the thermal- gravimetric method. The experiments were carried out using charcoal with particle size between 19,1 and 25,4 mm. The reaction was carried out at temperatures ranging from 800 to 950 deg C using CO{sub 2} and N{sub 2} atmospheres and potassium carbonate contents up to 3,5%. Potassium carbonate exhibited a great catalytic activity. Up to 2,5%, K{sub 2} CO{sub 3}, there was an increase in the rate of gasification with the increase in the potassium content. Beyond this point, the rate of reaction was not sensible to changes in the potassium content. (author) 2 refs., 5 figs.
2004-07-01
In this work an arrangement of thermohydraulic channels is presented that represent those four quadrants of a nucleus of reactor type BWR. The channels are coupled to a model of neutronic in two dimensions that allow to generate the radial profile of power of the reactor. Nevertheless that the neutronic pattern is of two dimensions, it is supplemented with axial additional information when considering the axial profiles of power for each thermo hydraulic channel. The stationary state is obtained the one it imposes as frontier condition the same pressure drop for all the channels. This condition is satisfied to iterating on the flow of coolant in each channel to equal the pressure drop in all the channels. This stationary state is perturbed later on when modifying the values for the effective sections corresponding to an it assembles. The calculation in parallel of the neutronic and the thermo hydraulic is carried out with Vpm (Virtual parallel machine) by means of an outline teacher-slave in a local net of computers. (Author)
1997-01-01
The mechanism of reduction of iron ore agglomerates by both isothermal and nonisothermal TG studies was investigated, and the work was complemented with the structural characterization of the total and partially reacted samples. Three different commercial hematite pellets were studied. The mechanisms of reduction were obtained under isothermal conditions, resulting in a fitting to chemical reaction models. Nonisothermal reduction was carried out using a TGA system (CAHN TG-171) from 600 to 1,000 degree centigree maintaining a lineal heating rate of 4,7 and 10 degree centigree/min, and the reducing atmospheres used were H2 (100%) and H2-CO(95:5). The kinetic parameters were evaluated by Coats and Redfern, Dixit and Ray and Prakash and Ray techniques. It was found that the lower the heating rate, the higher the reduction degree and the higher ...
2010-01-01
The objective of this work is to obtain an analytical solution of the neutron diffusion kinetic equation in one-dimensional cartesian geometry, to monoenergetic and multigroup problems. These equations are of the type stiff, due to large differences in the orders of magnitude of the time scales of the physical phenomena involved, which make them difficult to solve. The basic idea of the proposed method is applying the spectral expansion in the scalar flux and in the precursor concentration, taking moments and solving the resulting matrix problem by the Laplace transform technique. Bearing in mind that the equation for the precursor concentration is a first order linear differential equation in the time variable, to enable the application of the spectral method we introduce a fictitious diffusion term multiplied by a positive value which tends to zero. This procedure opened ...
2008-01-01
This work describes an analytical solution obtained by the expansion method for the spatial kinetics using the diffusion model with delayed emission for source transients in homogeneous media. In particular, starting from simple models, and increasing the complexity, numerical results were obtained for different types of source transients. An analytical solution of the one group without precursors was solved, followed by considering one precursors family. The general case of G-groups with R families of precursor although having a closed form solution, cannot be solved analytically, since there are no explicit formulae for the eigenvalues, and numerical methods must be used to solve such problem. To illustrate the general solution, the multi-group (three groups) time-dependent problem without precursors was solved and the numerical results of a finite difference ...
1998-01-01
A comparative evaluation of the gamma-ray analysis software VISPECT, in relation to two commercial gamma-ray analysis software packages, OMNIGAM (EG and G Ortec) and SAMPO 90 (Canberra) was performed. For this evaluation, artificial gamma ray spectra were created, presenting peaks of different intensities and located at four different regions of the spectrum. Multiplet peaks with equal and different intensities, but with different channel separations, were also created. The results obtained showed a good performance of VISPECT in detecting and analysing single and multiplet peaks of different intensities in the gamma-ray spectrum. Neutron activation analysis of the geological reference material GS-N (IWG-GIT) and of the granite G-94, used in a Proficiency Testing Trial of Analytical Geochemistry Laboratories, was also performed , in order to evaluate the VISEPCT ...
2001-01-01
Objectives: This study examines the structural and thermal modifications induced in dental enamel under dye assisted diode laser irradiation. The aim of this study is to verify if this laser-assisted treatment is capable to modify the enamel surface by causing fusion of the enamel surface layer. At the same time, the pulpal temperature rise must be kept low enough in order not to cause pulpar necrosis. To achieve this target, it is necessary to determine suitable laser parameters. As is known, fusion of the enamel surface followed by re-solidification produce a more acid resistant layer. This surface treatment is being researched as a new method for caries prevention. Method and Materials: A series of fourteen identically prepared enamel samples of human teeth were irradiated with a high power diode laser operating at 960 nm and using fiber delivery. Prior to irradiation, a fine ...
2002-01-01
In the present work, hair samples from populations suspected of contamination by mercury, in the localities of Serra do Navio, Vila Nova and Tartarugalzinho, in the State of Amapa, were analyzed. Hair samples of children under odontopediatric treatment were also analyzed for mercury, in order to study the possibility of transfer of mercury from the dental amalgam and also to obtain data of hair mercury in a control population of children. Another step of the work was the development of a method for the determination of selenium, by using the short-lived radioisotope 77mSe. After the certification of the method it was applied to the analysis of hair, nails and a vitamin supplement. A comparison was made with the results obtain ed by using the long-lived radioisotope of selenium, 75Se. The results obtained for mercury in the hair samples of populations ...
1996-01-01
The use of ceramic solid electrolytes for chemical sensors and the characterization of lanthanide III p-toluene-sulphonates as well as the chemical preparation of lutetium compounds are discussed. A Brazilian station for monitoring global atmospheric and the impacts on pollutants dispersion in Brazil are analysed. The catalytic liquefaction of sugar cane bagasse is considered as well as the study of higher alcohols reaction on zeolites is presented
1994-01-01
The results obtained from finite element thermal transient analyses performed in Charpy V-notch test specimens are presented in order to verify the validity of two recommendations included in ASTM A370 and E23 standards: the minimum immersion time of the specimen in a liquid bath to reach a isothermal state at test temperature. And the maximum time interval between the removal of the specimen from the bath and the execution of the test. (author). 7 refs, 16 figs, 3 tabs
1995-12-31
This work presents a mathematical modelling which uses the harmonic inductance concept on order to obtain voltage and torch equations of an induction machine. The methodology is presented. Two different situations are presented: the operation of the inducted motor feed by sinusoidal voltage wave and the operation of the same induction motor by a three-phase inductor 8 figs., 6 refs.
1984-01-01
Analised AE measurements permit definition and detection of initial critical damage occuring in CFRP in the course of dynamic testing. The qualitative assessment of these measurements requires a certain way of the processing, assignment and presentation of the collected AE data. An example is given to show how AE analysis allows form conclusion on the growth of damage in a CFRP sample. (orig.)
2008-07-01
The different nature of the E and P agreements recommends an analysis of the tax incidence in order to avoid the increasing of costs due to an inaccurate taxation process. The revenue obtained from Services Agreements must be, under the Brazilian legal system, taxed as the revenues obtained from the Concession Agreements, since those revenues are related to the risks supported, the investments and financial exposure, among others elements and not related to a specific public service provided. (author)
2008-07-01
The present work presents a group of algorithms, techniques and functionalities on alarms management which can be used efficiently on the treatment of 'disturbances' caused by the informal management of the alarm systems. Among the disturbances handled by these techniques, there is the recognition of intermittent alarms and false alarms, location of alarm floods and correlation between alarms, aiming the identification of communal root causes. The results will be presented through a case study on petrochemical alarm plants. At last, the results obtained by the utilization of such functionalities will be presented and discussed. (author)
1993-12-31
Sugar cane bagasse use as primary fuel, its potential, production cost on conventional steam cycle (Rankine cycle) more utilized in sugar cane industry or on GSTIG cycle, which use gas turbines and synthetical gas from sugar cane bagasse is presented. Parameters to optimize the sugar cane bagasse as fuel and obtain a competitive energetic potential are discussed 4 refs., 2 figs., 8 tabs.
1996-12-31
This work shows a study in laboratory, of the influence of different rolling conditions, continuous cooling and chemical composition on bainitic microstructure and properties of a low carbon Nb-Ti-B steel another one with addition of Cu-Ni-Cr. The results showed that in both steels were possible to obtain a bainitic microstructure with different levels of mechanical properties depending on the proportion of acicular constituents. (author) 5 refs., 17 figs., 2 tabs.
1980-02-15
This norm establishes the Standard Model for the Safety Analysis Report of Nuclear Fuel Reprocessing Plants, comprehending the presentation format, the detailing level of the minimum information required by the CNEN for evaluation the requests of Construction License or Operation Authorization, in accordance with the legislation in force. This regulation applies to the following basic reports: Preliminary Safety Analysis Report - PSAR, integrating part of the requirement of Construction License; and Final Safety Analysis Report (FSAR) which is the integrating part of the requirement for Operation Authorization.
1996-01-01
Six varieties of forages were analyzed by instrumental neutron activation analysis. The experimental conditions allowed the determination of Ca(5). K(%). Mg (mug/g). Mn(mug/g). Ti(mug/g) and V(ng/g) in 30 minutes, approximately. The accuracy of the method was evaluated by means of reference material analysis. The precision of the results was lower than 10%, except for Ti and some cases for Na was near 20%. (author)
1997-12-01
A method for developing digital protection systems based upon reliability and safety requirements has been proposed. Directives for assessing such conditions are suggested. Techniques and the most common tools employed in hardware evaluation and modelling of such architectures have also been shown. In order to estimate the software quality, several mechanisms to control design, specification, and validation and verification (V and V) procedures are suggested. (author). 12 refs., 1 fig.
2008-07-01
The oil activities in Brazil had been started in an intensive way by the years 30 and 40. During approximately 40 years only one agent had been executed the oil activities in this country: the PETROBRAS. Many of the fields explored in the past are nowadays in decline. These fields, not interesting for the majors, would be interesting for the small and medium enterprises. The present research analyses the mature oil fields and its regulation in Brazil, looking to the 'Constituicao Federal de 1988' and to the idea of social and economic development. (author)
1995-01-01
A methodology for quantitative analysis of geological, biological and environmental samples with a high fraction of light elements (atomic number less than 13), using energy dispersive X-ray fluorescence technique with radioisotopic excitation, is proposed. The proposed procedure is based on the method of Fundamental Parameters for analytical elements (
1997-12-31
This work relates the comparison between the results obtained with the two different methods of preparing pressed pastilles from the crushed sample. In this study, the reproductivity is evaluated, aiming to define the method that furnishes a better analytic precision. These analyses were realized with a X-ray fluorescence spectrometer at the Geology Department of the Federal University of Rio Grande do Norte 3 refs., 1 tab.
1992-12-31
This work presents the results of direct current multi-terminal systems implementation in the DINAM (power system dynamic analysis program) computational program, which was developed by ELETRONORTE (North of Brazil - electric power public utility). The applied methodology uses mathematical equations which consider AC to DC converters and DC varying. Case studies using the DINAM program illustrate the application of the proposed methodology. 4 refs., 5 figs.
1992-11-01
The main objective of this work is to describe the detailed derivation of a power sensitivity model, suited for the simulation and analysis of the low frequency dynamics in multi-machine networks. The proposed model is based on power sensitivities, used to establish the dynamic power balance conditions at the network buses. 143 refs., 74 figs., 8 tabs.
1987-12-31
A planning systems reflects not only the specific features of the sector where it takes place, but also the planner`s views about the regulatory process itself. It is shown that the Brazilian energy planning of recent years has been immature as far as it neither reflects the energy issues in their multiple manifestations nor legitimate the massive presence of the State, and of its enterprises in the sector, through an integrated planning system in order to construct a balanced energy matrix satisfying both the expectations of the productive sector and the social and environmental demands of society. 7 refs.
1987-12-31
This work analyses the results of performance tests conducted on the collector of the solar grain drying unit at Colegio Agricola de Camboriu, Universidade Federal de Santa Catarina (Brazil). The solar collector consists of a masonry construction with 32 m. long and 2,4 m. wide with a transparent o,4 mm. thick polyethylene film cover. The performance tests are conducted with two different heat absorber materials placed inside the collector and their effects are analysed. (author). 5 refs., 5 figs., 2 tabs
2005-07-01
This paper analyses proposed options for temporary storage of research reactor spent fuels. The results of this analysis were utilized to propose an option for the temporary storage of IEA-R1 research reactor spent fuels, until a definition of a national political decision about the final disposal of these spent fuels be established. (author)
1999-11-01
In the present paper the instrumental neutron activation analysis was applied to determine some essential and toxic elements in six agroindustrial by-products utilized to feed animal. The accuracy of the method was evaluated by means of reference material analysis. In general, the precision of the method was lower than 10% and the accuracy near to 5%. (author) 7 refs., 1 tab.
1999-01-01
In the present paper the instrumental neutron activation analysis was applied to determine some essential and toxic elements in six agroindustrial by-products utilized to feed animal. The accuracy of the method was evaluated by means of reference material analysis. In general, the precision of the method was lower than 10% and the accuracy near to 5%. (author)
2008-07-01
The market for ESCOs in Brazil has a great opportunity, by offering energy efficiency services related to natural gas use. The article presents a revision of ESCO concept and analyses the market potential for this specific segment, based upon data from the Useful Energy Balance. (author)
1993-12-31
This work analyse the influence of sample preparation in X-ray fluorescence and optical emission spectrometry. Carbon steel, low alloy steel, stainless steel and manganese steel samples, prepared using circular sanding with 40, 60, 150 and 400 granulometry, were studied. This work concludes that depending upon the analytical technique and for certain chemical elements, sanding influence exists and some elements remain without definite trend, and other elements becoming independent of sanding granulometry 4 refs., 4 figs., 8 tabs.
1993-01-01
This work analyse the influence of sample preparation in X-ray fluorescence and optical emission spectrometry. Carbon steel, low alloy steel, stainless steel and manganese steel samples, prepared using circular sanding with 40, 60, 150 and 400 granulometry, were studied. This work concludes that depending upon the analytical technique and for certain chemical elements, sanding influence exists and some elements remain without definite trend, and other elements becoming independent of sanding granulometry
1999-07-01
The central issue of debate was the need to align the energy sector's options and organization with changing global patterns of economic and social development, characterized by the increasing role played by the private sector, greater integration in the world economy, and new economic and social priorities such as efficiency, decentralization, deregulation, and a closer attention to environmental issues. The aim of the work was to present financial analysis of slump income program considering a Brazilian electric utility case study.
2000-07-01
This paper develops a simple model allowing a prospective analysis on the values of distribution marginal costs for the near future. Such a model concludes not to be unconcerned the affirmative that such a costs are always decreasing with the time. If the studies are concerned with the near future, it is possible that for certain areas, depending on the relative values of the parameters which composing the calculations, these values can be increasing. The final part of the work two examples of calculation which confirm the previous affirmatives.
1999-07-01
The aim of this work is to introduce and to analyze the energetic content of the gross domestic product of Rio Grande do Norte (a Brazilian state) economy in the period 1980-1994. Analysis plans, energy supply structure, energy consumption sectorial structure, and economic activity profile are presented. Just the qualitative evaluation is presented.
1999-07-01
The promotion of energy economy and efficiency is recognized as the single most cost-effective and least controversial component of any strategy of matching energy demand and supply with resource and environmental constraints. Historically such efficiency gains are not out of reach for the industrialized market economy countries, but are unlikely to be reached under present conditions by developing countries and economics in transition. The aim of the work was to analyze the energetic behavior in the Brazilian cities residential buildings.
1995-12-31
This work talks about the entrance of digital technology, in protection and control digital systems for electric power substations, in the Brazilian market. It makes a comparative evaluation between digital and conventional systems. Finally, the authors conclude that the digital systems present a better cost benefit rate considering not only financial but also functional aspects 4 refs., 1 fig.
1991-12-31
This work presents a new methodology for the laboratory reproduction of the real dynamic conditions which may occur in an electric system using a new equipment, the SDTR (Digital Simulator for Relays Tests) which objectives the testing and calibration of relays. This work shows a practical example using the SDTR equipment. 6 refs., 11 figs., 3 tabs.
1996-07-01
Materials under irradiation show structural modifications that result in properties alterations. The knowledge of these alterations is very important to give support to project modifications, materials specifications and process optimization in energy generation, with the purpose of minimizing the risk of failure. The metallographic and ceramographic tests are crucial for the performance analysis of materials under irradiation. This paper presents the stage of development of systems for preparing metallographic/ceramographic samples of irradiated fuel rods. (author)
1997-10-01
For describing the variation content in trace nutrients as result of food industrialization process, wheat flour, integral eggs and paste made from these raw materials were analyzed using neutron activation analysis technique. The concentration of the elements Cr, Fe, Zn and Ca were found to be roundly ng/g and {mu}g/g. (author). 14 refs., 1 fig., 5 tabs.
1991-01-01
Determination of the sup(232)Th concentration in excreta samples (urine and feces) was performed. Two groups of persons were analyzed. The first one, A, constituted by persons non occupationally exposed and the second one, B, by workers occupationally exposed. This study clearly showed that exists occupational irradiation of sup(222)Th. (author)
1993-12-31
This paper shows a consistent comparative technical-economic analysis between two distinct structural standards, while propose reliable parameters for future chooses between metallic and concrete power transmission towers. In dependence of the main characteristics of each transmission line, the concrete structures, when concept under updated techniques, presents good perspectives on rational utilization 4 refs., 5 figs., 4 tabs.
1989-03-01
The contracts of fuel gas supply settled between the REGAP (Gabriel Passos Refinery) and the CEMIG (Energetic Company of Minas Gerais State, Brazil), will allow a supply of 230.000 m{sup 3} per day of this gas, in industrial region of Betim, Contagem and Belo Horizonte- Brazil. This paper analysis the main involvements of the electric power substitution to be sold to the steam generations, by full gas, that will be used for the same aim.
2005-07-01
This paper presents a preliminary study of Semi Parametric Neutron Activation Analysis in the steady state flux conditions. It was verified that the used standards in the routine analysis of the radiochemistry analysis of CDTN/CNEN presents the same statistical induced activity for the same irradiation time through the last six years. From these results, that indicates the flux stability, it is purposed a new approach to the technique. (author)
2008-01-01
This study consists on the application of the Failure Modes and Effects Analysis (FMEA), a hazard identification and a risk assessment technique, to the Emergency Cooling System (ECS), of an experimental nuclear power plant. Such analysis intends to identify possible weaknesses on the design of the system and propose some improvements in order to maximize its reliability. (author)
1989-10-01
This paper presents the evolution of the classic lines for the ductile iron preparation in the large foundries, ordinarily big energy consumers is examined. Through the application of immediate conception on the heat transmission and balance, the realization of expressive gains on electrical consummation is thought possible. The industrial exploitation resulting from the implanted project was analysed and judged to satisfy the original expectations. (author). 11 drawings, 1 table
Analysis on a electron gun for metal fusion. Analise de um canhao de eletrons para fusao de metais
1987-01-01
The characteristics of the electron beam of the HK-011600 DELTA, electron gun for metal fusion at the 'Divisao de Materiais do Instituto de Pesquisa e Desenvolvimento do CTA (PMR/IPD/CTA)', is analyzed. In this analysis, the Pierce gun model and the SLAC computational code for electron optics are used. The electron beam R and Z profiles are obtained in the gun region and in the magnetic lenses region. The behaviour of the electron beam in the prism region is also discussed using a simple model. (author)
Analysis of turbulence spectrum in the TBR-1. Analise do espectro de turbulencia no TBR-1
1987-01-01
The fluctuation signals of ion saturation current in plasma edge of the TBR-1 tokamak were measured, using three Langmuir probes aligned to toroidal magnetic field direction, for detecting trapped particle modes in this region. The construction of Langmuir probes is also described. The dispersion relation and respective spectra were obtained using spectral technique developed by Powers et all. The index of spectra decay for high frequencies, as well as radial variation of these index and fluctuation levels, were also determined. (M.C.K.)
1991-12-31
The importance of decisions about capital investment, and an analysis of several factors to be considered by private enterprises, before its evolvement on hydroelectric power plants construction to self electric power generation, are presented. Simulations of the investment, its financing alternatives and its construction terms, showing the variations of these parameters on electric costs are also reported. 3 figs., 2 tabs., 4 refs.
1987-12-31
This work aims to qualitatively evaluate the efficiency of each parameter which is concerned to the improvement of the dynamic stability of Cachoeira Porteira hydroelectric power plant transmission system. The computer program used is named and compared to others available. Some results are presented 5 refs., 7 figs., 1 tab.
1989-01-01
New mixed finite element formulations for plane elasticity problems are presented with no limitation in the choice of conforming finite element spaces. Adding least square residual form of the governing equations to the classical Galerkin formulation the original saddle point problem is transformed into a minimization problem. Stability analysis, error estimates and numerical results are presented, confirming the error estimates and the good performance of this new formulation. (author)
1996-12-31
In this work, s series of reduction experiments under isothermal and load conditions were carried out (ut to 1130 deg C), using different types of brazilian iron ores containing specular hematite, martite, goethite, limonite as well as criptocrystalline/microcrystalline hematite, with different textures (lepidoblastic, granoblastic, micro granular and interlaced), used as blast furnace charge. (author) 23 refs., 3 figs., 1 tab.
1995-06-01
Considering the importance that has the kinetic characteristics of polymers crystallization, to evaluate quickly and simultaneously the speed of crystallization (1/t{sub 0}.5: seconds {sup -1}) and growth spherulitic (G:nm/min) a methodology was developed; for this was used an analyzer of images connected to a microscope with platen of heating. G was determined measuring the increase of the radius of the spherulite in stored images consecutively during isothermal crystallization and 1/t{sub 0}.5 using the changes in intensities of gray average (IGm) of the same images. As relation between IGm and the crystallinity degree (1-{lambda}) considers as a model of the equation: (1-{lambda}) =(1/Q)In (IGo/(IGo-IGm )), where Q is a constant that includes the absorption coefficient of light and the thickness of the sample, and Go is the intensity of gray corresponding to the incident beam. Thus it was possible to obtain the kinetic crystallization of three polymers (nylon 6, polypropylene and polyethylene of low density); these results were reproducible and coincident with the reported in literature. [Spanish] Considerando la importancia que tienen las caracteristicas cineticas de cristalizacion de los polimeros, se desarrollo una metodologia para evaluar rapidamente y en forma simultanea la velocidad de cristalizacion (1/t{sub 0}.5: segundos{sup -1}) y la velocidad de crecimiento esferulitico (G:nm/min); para esto se utilizo un analizador de imagenes acopladas a un microscopio con platina de calentamiento. G se determino midiendo el incremento del radio de las esferulitas en imagenes almacenadas consecutivamente durante cristalizaciones isotermicas y 1/t{sub 0}.5 utilizando los cambios en intensidades de gris media (IGm) de las mismas imagenes. Como relacion entre IGm y el grado de cristalinidad (1-{lambda}) se plantea como modelo de la ecuacion: (1-{lambda})(1/Q)In (IGo/(IGo-IGm)), donde Q es una constante que incluye el coeficiente de absorcion de luz y el espesor de la muestra y Go es la intensidad de gris correspondiente al haz incidente. Asi fue posible obtener las cineticas de cristalizacion de tres polimeros (nylon 6, polipropileno y polietileno de baja densidad); estos resultados fueron reproducibles y coincidentes con los reportados en la literatura.
2004-07-01
The development of a software is presented that simulates the punctual kinetics of a nuclear reactor of investigation model TRIGA Mark III, generating the answers of the reactor low different algorithms of control of power. The user requires a graphic interface that allows him easily interacting with the simulator. To achieve the proposed objective, first the system was modeled in open loop, not using a mathematical model of the consistent reactor in a system of linear ordinary differential equations. For their solution in real time the numeric method of Runge-Kutta-Fehlberg was used. As second phase, it was modeled to the system in closed loop, using for it an algorithm of control of the power based on fuzzy logic. This software has as purpose to help the investigator in the control area who will be able to prove different algorithms for the control of the power of the reactor. This is achieved using the code source in language C, C++, Visual Basic, with which a file is generated. DLL and it is inserted in the simulator. Then they will be able to visualize the results as if their controller had installed in the reactor, analyzing the behavior of all his variables that will be stored in files, for his later study. The easiness of proving these control algorithms in the reactor without necessity to make it physically has important consequences as the saving in the expense of fuel, the not generation of radioactive waste and the most important thing, one doesn't run any risk. The simulator can be used how many times it is necessary until the total purification of the algorithm. This program is the base for following investigation processes, enlarging the capacities and options of the same one. The program fulfills the time of execution satisfactorily, assisting to the necessity of visualizing the behavior in real time of the reactor, and it responds from an effective way to the petitions of changes of power on the part of the user. (Author)
1989-12-31
For boiler soot blowing converging-diverging nozzles are employed, whose function is to convert thermal energy of a gas into kinetic energy to remove the deposits that adhere to the heat exchanger surfaces. In this paper are described the experimental equipment and the methods for flow, dynamic pressure, discharge velocity and air expansion factor calculation in each nozzle, as a function of its design geometry, utilizing air from a five stage centrifugal compressor. The graphic analysis of the results, concludes that the most efficient nozzles are not the ones than develop the greatest velocity, but the ones of highest dynamic pressure at the outlet. The nozzle geometry that allows obtaining the maximum dynamic air pressure at the discharge is A{sub 2}/A{sub g}=1.3676 [Espanol] Para el deshollinado de calderas se utilizan las toberas convergentes-divergentes, cuya funcion es convertir la energia termica de un gas en energia cinetica para remover los depositos que se adhieren a las superficies de intercambio de calor. En este trabajo se describen el equipo experimental y los metodos de calculo para flujo, presion dinamica, velocidad a la descarga y factor de expansion del aire en cada tobera, como funcion de su geometria de diseno. Durante la experimentacion se evaluaron siete disenos diferentes de toberas, empleando aire de un compresor centrifugo de cinco etapas. Del analisis grafico de los resultados, se concluye que las toberas mas eficientes no son las que desarrollan mayor velocidad sino las de mayor presion dinamica de la salida. La geometria de tobera que permite obtener la maxima presion dinamica del aire a la descarga es A{sub 2}/A{sub g} = 1.3676.
1998-09-01
A new procedure for the simultaneous estimation of kinetic constant related to both ammonia and nitrite oxidisers is proposed which takes into account the necessity for more rapid, simple, reliable and automatic procedures to monitor activated sludge systems. This goal was obtained by providing the ANITA biosensor, previously developed to measure nitridation kinetics, with an oxygen electrode. Simultaneous titrometric and respirometric data may be thus obtained. Combining these two series of data, linked by the stoichiometry of the ammonia and nitrite oxidation reactions, an accurate and reliable estimation steps can be achieved in about an hour. [Italiano] Si propone in questo lavoro una nuova procedura per una piu` accurata valutazione delle costanti cinetiche di nitrosazione e nitratazione. Tale lavoro si inquadra nell`ambito di una piu` ampia ricerca mirante a fornire ai gestori degli impianti metodologie rapide, semplici, affidabili e automatizzabili per monitorare l`andamento dei processi biologici ed in grado di segnalare in tempo reale il verificarsi di improvvisi cali di efficienza. Il biosensore ANITA, fino ad ora utilizzato per il monitoraggio della cinetica di nitrosazione e per la misura dell`ammoniaca in soluzione, e` stato dotato di una sonda ad ossigeno. La nitrificazione viene in questo modo monitorata attraverso due metodologie di misura diverse ed indipendenti: la titolazione e la misura dell`ossigeno disciolto (OD). Tale procedura permette di distinguere le due cinetiche batteriche (nitrosazione e nitratazione) e consente di caratterizzare l`attivita` sia dei batteri nitrosanti che dei batteri nitranti con prove della durata di circa un`ora.
2007-07-01
In this work the initial results of the joining of an arrangement of 36 channels in parallel are studied to a modal neutronic kinetic model to represent the core of a BWR type reactor. The set of channels is obtained group the assemblies of that it consists the core in an arrangement of concentric rings, for later on to subdivide each ring in four parts to assign each segment to a quadrant of the core. The obtained channels are coupled to a modal kinetics model that considers the fundamental way and the first harmonic. The obtained solution represents the radial distribution and power azimuthal, the one which is feedback to the channels to update the thermohydraulic variables. The restriction that the pressure drop is same for each channel it is only imposed as initial condition, like part of the stationary state, and it is allowed that the pressure drop in the assemblies them it is different in each channel during a reactivity interference. For the tests to the system, it is convenient to select a relatively big core and that it operates near their stability frontier, for that the channels are dimensioning according to the case 9 of the Stability Benchmark of the Ringhals Swedish plant, organized by the Nuclear Energy Agency in 1994. In general, they reproduce the results of this benchmark, when reproducing oscillations outside of phase, with the additional results that the quadrants 1 and 2 of the core present oscillations of more width that the quadrants 3 and 4. The set group nuclear-thermohydraulics it is solved numerically by means of the outline master-slave of distributed calculation implemented by means of Parallel Virtual Machine (PVM). (Author)
2003-07-01
In this work the dynamic behavior of a consistent system in fifteen channels in parallel that represent the reactor core of a BWR type, coupled of a kinetic neutronic model in one dimension is studied by means of time series. The arrangement of channels is obtained collapsing the assemblies that it consists the core to an arrangement of channels prepared in straight lines, and it is coupled to the unidimensional solution of the neutron diffusion equation. This solution represents the radial power distribution, and initially the static solution is obtained to verify that the one modeling core is critic. The coupled set nuclear-thermal hydraulics it is solved numerically by means of a net of CPUs working in the outline teacher-slave by means of Parallel Virtual Machine (PVM), subject to the restriction that the pressure drop is equal for each channel, which is executed iterating on the refrigerant distribution. The channels are dimensioned according to the one Stability Benchmark of the Ringhals swedish plant, organized by the Nuclear Energy Agency in 1994. From the information of this benchmark it is obtained the axial power profile for each channel, which is assumed as invariant in the time. To obtain the time series, the system gets excited with white noise (sequence that statistically obeys to a normal distribution with zero media), so that the power generated in each channel it possesses the same ones characteristics of a typical signal obtained by means of the acquisition of those signals of neutron flux in a BWR reactor. (Author)
2004-07-01
The objective of the written present is to propose a methodology for the joining of the codes RELAP5/SCDAPSIM and NESTLE. The development of this joining will be carried out inside a doctoral program of Engineering in Energy with nuclear profile of the Ability of Engineering of the UNAM together with the National Commission of Nuclear Security and Safeguards (CNSNS). The general purpose of this type of developments, is to have tools that are implemented by multiple programs or codes such a that systems or models of the three-dimensional kinetics of the core can be simulated and those of the dynamics of the reactor (water heater-hydraulics). In the past, by limitations for the calculation of the complete answer of both systems, the developed models they were carried out for separate, putting a lot of emphasis in one but neglecting the other one. These methodologies, calls of better estimate, will be good to the nuclear industry to evaluate, with more high grades of detail, the designs of the nuclear power plant (for modifications to those already existent or for new concepts in the designs of advanced reactors), besides analysing events (transitory and have an accident), among other applications. The coupled system was applied to design studies and investigation of the Laguna Verde Nuclear power plant (CNLV). (Author)
1999-01-01
Mechanical vibration signals play an important role in anomalies identification resulting of equipment malfunctioning. Traditionally, Fourier spectral analysis is used where the signals are assumed to be stationary. However, occasional transient impulses and start-up process are examples of nonstationary signals that can be found in mechanical vibrations. These signals can provide important information about the equipment condition, as early fault detection. The Fourier analysis can not adequately be applied to nonstationary signals because the results provide data about the frequency composition averaged over the duration of the signal. In this work, two methods for nonstationary signal analysis are used: Short Time Fourier Transform (STFT) and wavelet transform. The STFT is a method of adapting Fourier spectral analysis for nonstationary application to ...
1999-11-01
The loss of coolant accidents (LOCA) in pool type research reactors are normally considered as limiting in the licensing process. This paper verifies the viability of the computer code 3D-AIRLOCA to analyze LOCA in a pool type research reactor, and also develops two computer codes LOSS and TEMPLOCA. The computer code LOSS determines the time tom drawn the pool down to the level of the bottom of the core, and the computer code TEMPLOCA calculates the peak fuel element temperature during the transient. These two coders substitutes the 3D-AIRLOCA in the LOCA analysis for pool type research reactors. (author) 11 refs., 6 figs., 2 tabs.
1999-01-01
The loss of coolant accidents (LOCA) in pool type research reactors are normally considered as limiting in the licensing process. This paper verifies the viability of the computer code 3D-AIRLOCA to analyze LOCA in a pool type research reactor, and also develops two computer codes LOSS and TEMPLOCA. The computer code LOSS determines the time tom drawn the pool down to the level of the bottom of the core, and the computer code TEMPLOCA calculates the peak fuel element temperature during the transient. These two coders substitutes the 3D-AIRLOCA in the LOCA analysis for pool type research reactors. (author)
1997-10-01
Thermoluminescent dosemeter (TLD) based neutron individual monitoring needs a more rigorous thermoluminescent (TL) emission spectra analysis than photon monitoring. For analysis automation and optimization, a computational program has been developed in Visual Basic. It reads the input data from a Ascii file generated by the emission spectra exportation of the evaluated TLD`s. The system can be divided in 4 parts: TL spectra filtration and correction (manual or automatic), charge integration of the corrected reading of each TLD, neutron individual dose calculation for each monitored worker and interface with the user. As main output, the system generates one text file which feeds the IRD Individual Monitoring Data Bank. (author). 5 refs., 1 fig.
2006-07-01
Rating agencies have strong influence on the international financial market for both public and private debt. Host countries also have due influence on local enterprises, by means of the macro economic policy. In the case of default of sovereign debt or capital controls, domestic firms may have serious difficulties in meeting their obligations in foreign currency. This explained the so called sovereign ceiling to the corporate ratings. This explicit ceiling has been abandoned by the main rating agencies, as some corporations may have more means to meet their debt than sovereigns. Oil companies are a good example. This paper aims to explain the variables that help explain the Brazilian sovereign ratings and PETROBRAS ratings, using the ordered logit method, with emphasis on the factors that influenced the piercing of the severing ceiling by PETROBRAS in 2001. (author)
2004-07-01
The objective of this paper is to discuss the possible impacts on the Brazilian economy of an oil shortage crisis and its effects on the domestic market for liquid fuels. The results were obtained from simulations using a multi-sector general equilibrium model. The scenarios used in the numerical experiments were characterized by different constraining levels in imports of crude oil and oil products and also by the ability gasoline may be substituted by fuel ethanol. It is shown that the economic effects depend to a large degree on the substitution flexibility between liquid fuels. Thus it is expected that the introduction of flex-fuel vehicles in the light-duty fleet will make the Brazilian economy much less vulnerable in the event of an external oil-supply shock. (author)
2009-01-01
The aim of this work was to propose rationalization in the synthesis, analysis and purification of radiopharmaceutical 177 Lu3+ - DOTATATO for diagnostic and therapeutic use in neuroendocrine tumors, as well as for evaluation g biodistribution of this radiopharmaceutical an animal-mode. The complexation reaction for the synthesis of radiopharmaceutical was carried out in ammonium acetate buffer 0.5 M, p H 7.0, for 30 minutes at 95 deg C. The radiochemical purity was
Study of the Skyrme model solitons. Estudo sobre os solitons do modelo de Skyrme
1992-01-01
The analysis presented in this thesis is based on the existence of topological structures in the Skyrme Model. The Skyrme Model can be considered as an idealization of QCD in the range of energy in which it is too complicated to describe the hadronic interactions using directly the fundamental fields, the quarks. The first chapters of this thesiswe concentrate on the theoretical basis of the model. The solutions for the Skyrme model in the hedgehog SU (2) representation are analised as functions of the parameters of the model. Sum rules obtained from the Euler-Lagrange differential equations are efficient tools for this analysis, and use is made of the original Derrick's argument regarding stability in a constructive way. It is found that the evolution of the solutions seems to be appropriately described by a specific control parameter phi, which has distinctive ...
1985-01-01
The heavy metal pollution in Sepetiba Bay and Paraiba do Sul River - Guandu River is studied by analysis of critical parameters. This ones are employed in environmental impact determination of nuclear installations. Three critic metals (Cr, Zn, Cd) and four (Pb, Cu, Zn, Cr) ones are lauched by the industrial park of Sepetiba Bay and Paraiba Vale respectively. (M.A.C.)
2005-07-01
New pipelines, request the use of great amount of tubes stored during its construction. Therefore, the cost generated by the storage areas motivates the reconsideration of the stockpiling system. Large areas demand high costs related to its acquisition or rent. The use of small areas can reduce the immediate cost with rent, but also can increase the total cost due to damage of the tubes or increase the risk at the storage conditions. The same considerations could be made for inadequate use of support materials on the stockpiling piles, regarding the quality or amount used. This work presents the modelling of the pyramidal stockpiling system of steel tubes and evaluations to a better configuration. (author)
1996-05-01
The use of redundancy to increase the reliability of industrial systems make them subject to the occurrence of common cause events. The industrial experience and the results of safety analysis studies have indicated that common cause failures are the main contributors to the unreliability of plants that have redundant systems, specially in nuclear power plants. In this Thesis procedures are developed in order to include the impact of common cause failures in the calculation of the top event occurrence probability of the Auxiliary Feedwater System in a typical two-loop Nuclear Power Plant (PWR). For this purpose the Multiple Greek Letter Model is used. (author). 14 refs., 10 figs., 11 tabs.
1996-01-01
The use of redundancy to increase the reliability of industrial systems make them subject to the occurrence of common cause events. The industrial experience and the results of safety analysis studies have indicated that common cause failures are the main contributors to the unreliability of plants that have redundant systems, specially in nuclear power plants. In this Thesis procedures are developed in order to include the impact of common cause failures in the calculation of the top event occurrence probability of the Auxiliary Feedwater System in a typical two-loop Nuclear Power Plant (PWR). For this purpose the Multiple Greek Letter Model is used. (author). 14 refs., 10 figs., 11 tabs
2004-04-01
Quantitative GC-FID was evaluated for analysis of methylated copaiba oils, using trans-(-)-caryophyllene or methyl copalate as external standards. Analytical curves showed good linearity and reproducibility in terms of correlation coefficients (0.9992 and 0.996, respectively) and relative standard deviation (< 3%). Quantification of sesquiterpenes and diterpenic acids were performed with each standard, separately. When compared with the integrator response normalization, the standardization was statistically similar for the case of methyl copalate, but the response of trans-(-)-caryophyllene was statistically (P < 0.05) different. This method showed to be suitable for classification and quality control of commercial samples of the oils. (author)
1983-01-01
Industrially acceptable silver azide is obtainable in a free flowing crystal form by synthesis in an alkaline medium while using sodium carboxy methyl cellulose as a surface active agent. The silver azide was identified by means of X-ray diffraction and its purity was determined by means of a modified Heraeus nitrogen analyzer. Physical properties namely melting point, thermal sensitivity and reactivity were examined by means of differential thermal analysis and thermal stability using thermogravimetric analysis. The silver azide, unlike the lead azide, exhibited remarkable chemical stability when subjected to a high degree of humidity for six months, it showed no change while lead azide had completely decomposed after only four months exposure to the same conditions. Again silver azide, unlike lead azide showed itself to be chemically stable when exposed to the ...
2006-01-01
In the present work a procedure for determination of the isotopic ratio 238U/235U in UF6 samples was established using a quadrupole mass spectrometer with ionization by electron impact and ion detection by Faraday cup or electron multiplier. For this, the following items were optimized in the spectrometer: the parameters in the ion source that provided the most intense peak, with good shape, for the corresponding mass of the most abundant isotope. The resolution that reduced the non linear effects and the number of analytic cycles that reduced the uncertainty in the results. The measurement process was characterized with respect to the effects of mass discrimination, linearity and memory effect. The mass discrimination showed to be linearly dependent of the sample pressure in the batch volume, for the pressure ranges from 0.15 to 0.30 ...
2005-07-01
A monobuoy monitoring system was developed and installed on 2004 in two oil terminals of TRANSPETRO. The main purpose of this system is to assure that monobuoys will be assisted during offloading operations, which will reduce the risk of accidents and detect immediately damages on mooring lines and equipment. The system comprises a Control Module on terminal site and a Remote Monitoring Unit, installed on each monobuoy. The link between modules is provided by an UHF radio-modem. The parameters acquired are pitch, roll, heave, geographic position, internal variables, and, if available, pressure and temperature of lines, traction on mooring system, etc. Positioning information is processed by the PETRONAV Positioning System. The whole process is registered and monitored on terminal with graphical interface. This article describes the development and installation of the system and the preliminary analysis of data produced since the system was installed. (author)
1992-08-01
This work is concerned with DC and Ac small signal models of DC-DC converters suitable for analysis and design of compensating circuits in closed-loop operation. It demonstrates that the models obtained theoretically are generic because they can represent the conventional hard switching PWM converters and Quasi-Resonant ones. A novel DC and Ac small large signal modeling approach is presented. The large and small circuits models to dc-dc converters is obtained. 47 refs., 81 figs., 11 tabs.
2005-07-01
The objective of this paper is offer to the industry an example of successful project finance in an emergent country. The Bolivia-Brazil pipeline was projected to develop an industry of natural gas in Brazil. The total costs invested was around US$ 1, 5 billion (Brazilian side) and BID, BIRD, CAF, BEI, BNDES- Finame, Marubeni, Mediocredito with main lenders. There are tree contracts with Ship or Pay clauses that are the main guarantees of the project. We will describe the mains variables of this project and the economic model that was created to calculate the tariff and project all financial reports of Bolivia-Brazil Pipeline. (author)
1993-10-01
Economic aspects of industrial production of sugar cane and automotive alcohol fuel, the relation between its production and electric energy consumption, electric energy costs to self generated electric power and concessionary supply, involved in plant production on Ribeirao Preto, SP, Brazil, are presented. Studies to verify the relationships between sugar and alcohol production with milling ours as well as sugar cane processed with sugar and alcohol produced are also discussed 27 refs., 12 figs., 38 tabs.
1997-12-31
This work presents a study concerning the nature of a data base of real loads, obtained as a time series. The main idea is to verify if the process which origins load slopes contains certain regularities, and if these exist, where can they be detected. Also studied is a process which does not present any periodicity. The distinction in between these two behaviours correspond to the stochastic or chaotic nature of the processes, which is discussed. The methodology is presented 8 refs., 15 figs., 5 tabs.; e-mail: gustavo, zambroni, germano, alex at iee.efei.rmg.br
1988-01-01
The serum parathyroid hormone levels obtained in 29 patients with proven primary hyperparathyroidism using two segment-specific radioimmunoassays, one amino-terminal and one carboxyl-terminal specific, were studied. The results were compared to those obtained in 69 normal individuals and 10 patients with hypercalcemia not-related to primary hyperparathyroidism. Analyzing the sensitivity and specificity for the diagnosis of primary hyperparathyroidism in the group of patients with hypercalcemia, the values of 82.8% and 100% were obtained for the amino-terminal and 59% and 70% for the carboxy-terminal assay, measuring the bioactive portion of the molecule, has better diagnostic power and that the concomitant serum calcium measurement is mandatory. (author)
2004-07-01
The Universidade Federal do Rio Grande do Norte has been developing prototype ovens, which work with natural gas. All the project of the prototypes, which will be applied to ceramic, bread bake industry and incineration of the hospital garbage, needs to be studied, developed and tested carefully until its conclusion. Then VRML language (Virtual Reality Modelling Language) is used as a tool in the study of the engineering projects and simulation of some tests. The main benefits of the use of this tool are: finding and solving problems in the project of the prototypes faster; optimization in the project since the three-dimensional visualization facilitates the study ; and simulation of aspects of functioning of the ovens before its construction. (author)
1998-07-01
Pipe coating damage provide several considerations during pipeline contruction. This is an interesting subject to be investigated specially by people involved in that area. Some projects (Brazil and abroad) were established, considering land and sea transportation. These recent statistics show reduced incidence on Polyethylene damaging. On viewpoint of costs, Coal-Tar Enamel and FBE Coatings present the lower coating repair values for highway transported pipes. For sea transportation, repais on Polyethylene and FBE Coatings were the cheapest. Finally, this paper reccomends important nercessary cares to be taken as to minimize the occurrance of coating damage. (author)
2000-07-01
In order to calculate the neutron flux in nuclear reactors, B1 or P1 equations are solved by numerical methods for several groups of energy. The neutron fluxes obtained from the solutions of the B1 and P1 equations are similar when they are applied to large nuclear power reactors. However, an important difference between the two fluxes is that the system of P1 equations uses one more approximation than the B1 system and then, its flux is less precise. The present work shows the relations between both equations and analyzes for what conditions the two equations systems are equivalent. Furthermore, this equations are numerically solved in 54 groups of energy for a quadrangular arrange. (author)
2000-07-01
This paper presents the development of a computer program for exergy and economic analysis of cogeneration systems applying gas turbine associated to the absorption refrigeration system. The computer program selects gas turbine systems viewing the operation under thermal parity through a data base composed by gas turbines commercially available in the market, under the ISO (International Standard Organization). The computer program corrects the system performance parameters selected for the installation local conditions. The exergy and economic analysis are made based on the lowest exergy manufacturing cost where the best system is considered. A case study of the computer program application is presented.
2009-07-01
A laboratory experiment that enables the professor to introduce the problematic of sustainable development in pharmaceutical chemistry to undergraduate students is proposed, using a simple synthetic procedure. Cholesteryl acetate is prepared by the esterification of cholesterol using Montmorillonite K10 as heterogeneous catalyst. Cholesterol and cholesteryl acetate are characterized by spectroscopic ({sup 1}H RMN, {sup 13}C RMN, FTIR) and thermal analysis techniques. The thermal methods are used to introduce the concepts of polymorphism and the nature of mesophases. (author)
2009-01-01
A laboratory experiment that enables the professor to introduce the problematic of sustainable development in pharmaceutical chemistry to undergraduate students is proposed, using a simple synthetic procedure. Cholesteryl acetate is prepared by the esterification of cholesterol using Montmorillonite K10 as heterogeneous catalyst. Cholesterol and cholesteryl acetate are characterized by spectroscopic (1H RMN, 13C RMN, FTIR) and thermal analysis techniques. The thermal methods are used to introduce the concepts of polymorphism and the nature of mesophases. (author)
2008-07-01
Even though technical-economical barriers still exist for the development of an economy based in the hydrogen, these difficulties are opportunities for the appearance of new business of goods and services, energetic matrix diversification, focusing of researches activities, development and support to provide sustainability to the new economy. This study presents the technical-economical comparison of hydrogen production and supply models, using the so-called Spilled Turbinable Energy of the Itaipu Hydroelectric Power Plant and available for the transport sector. The substitution of the urban collective diesel bus fleet with fuel cell buses in Foz do Iguacu city was used as a case study in this work. (author)
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