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Submitted by Marco Antonio Oliveira da Silva (maosilva@ipen.br) on 2017-10-27T12:15:25Z No. of bitstreams: 0 / Made available in DSpace on 2017-10-27T12:15:25Z (GMT). No. of bitstreams: 0 / A síntese de zeólitas a partir de cinzas leves e pesadas de carvão mineral foi realizada por tratamento hidrotérmico alcalino, as quais foram nomeadas ZCL e ZCP, respectivamente. As zeólitas organomodificadas ZML e ZMP foram obtidas a partir da modificação superficial de ZCL e ZCP, respectivamente, utilizando o surfactante catiônico brometo de hexadeciltrimetilamônio. A partir das soluções remanescentes geradas na síntese de ZCL e ZCP foi possível sintetizar duas novas zeólitas. As características físicoquímicas dos nanomateriais zeolíticos sintetizados, bem como de suas respectivas matérias primas, tais como: capacidade de troca catiônica, massa específica, área específica, composição química, mineralógica e morfológica, entre outras, foram determinadas. Os adsorventes ZML e ZMP foram utilizados na remoção dos corantes Azul Direto 71 (DB71) e Rodamina B (RB) de soluções aquosas em sistema de batelada. Desta forma, quatro sistemas DB71/ZML, RB/ZML, DB71/ZMP e RB/ZMP foram investigados. Os modelos de pseudoprimeira ordem e pseudo-segunda ordem foram aplicados aos dados experimentais para o estudo da cinética de adsorção. O modelo de pseudosegunda ordem foi o que melhor descreveu o processo de adsorção de todos os sistemas corante/zeólita organomodificada. O equilíbrio da adsorção foi analisado a partir de quatro modelos de isoterma, sendo eles: Langmuir, Freundlich, Temkin e Dubinin-Radushkevich (D-R). Os resultados mostram que os modelos de Freundlich e Langmuir melhor descreveram os dados experimentais dos sistemas DB71/ZML e DB71/ZMP, respectivamente. Para os sistemas com RB, o modelo de D-R foi o que melhor se ajustou para ambos adsorventes ZML e ZMP. O planejamento fatorial 24 foi aplicado para a análise dos seguintes fatores que influenciam o processo de adsorção: concentração inicial do corante (Co), pH, dose de adsorvente (M) e temperatura (T). De acordo com as condições estudadas concluiu-se, com o intervalo de confiança igual a 95%, que para o sistema DB71/ZML, os fatores e suas interações que mais influenciam foram C0, M, pH, pH*M, pH*C0, M*C0, pH*M*C0, nessa ordem. No sistema DB71/ZMP, a ordem de influência foi: M, C0, pH, pH*M, pH*C0, M*C0, pH*M*C0. Para os sistemas RB/ZML e RB/ZMP, os resultados foram: M, C0, M*C0, pH, pH*M e M, C0, M*C0, respectivamente. O equilíbrio de adsorção foi atingido em cerca de 40 min para todas as amostras. As porcentagens de remoção do DB71 estavam na faixa de 50 80% e 20 50% para ZML e ZMP, respectivamente. A faixa de porcentagens de remoção do RB variou entre 60 80% e 30 50% para ZML e ZMP, respectivamente. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

<p>  </p> <p>Betavoltaics are self-contained  radioisotope power sources where radioisotopes irradiate a semiconductor and  generate electricity similar to a photovoltaic cell. Betavoltaics differ from  other power sources as it is ideal for long-lasting (>20 years), low,  continuous power applications where battery replacement is not feasible. Ideal  functions for betavoltaics include sensors in hard to reach places such as  underwater and deep space applications, as well as cardiac pacemakers where  power source replacement is undesirable or impossible. However, betavoltaics  are limited in application by its power output since it only produces power in  the nanowatt range. Betavoltaic performance can be improved by two methods:  Increasing the amount of activity of the radioisotope or increasing the  performance of the semiconductor. Currently, commercial betavoltaics utilize a  titanium tritide film to irradiate a gallium arsenide semiconductor. The  objective of this dissertation is to identify a tritium storage medium that  can produce more power in the betavoltaic than the currently used titanium  tritide. This was done in three steps: First, metal film options were  simulated in MCNP to evaluate tritium substrate self-shielding, semiconductor  beta irradiation and determine ideal thicknesses. Second, metal film options  at ideal thicknesses were manufactured and evaluated during the hydrogen  loading process to determine the viability of materials fully absorbing  hydrogen. Lastly, the loading kinetics would be evaluated to further investigate  hydride/tritide formation in the storage medium if full loading is not  realized to determine the ideal thickness required, or if other factors during  the loading process need to be considered.</p> <p>Metallic films were evaluated to  maximize tritium packing and optimized for minimizing self-shielding to  improve performance for betavoltaic cells beyond the titanium tritide films  currently used. Ideal, fully loaded tritium metallic films, such as lithium,  aluminum, titanium, magnesium and palladium tritides, were simulated in MCNP6  (Monte Carlo N-Particle 6) to evaluate power deposition into a gallium  arsenide semiconductor by varying the thickness of the films. Lithium was  identified as the best storage option with an optimal thickness of 4 μm and a  theoretical betavoltaic current output of 644 nA for a gallium arsenide  semiconductor, tripling the current output emitted by an ideal titanium-loaded  film. </p> <p>The viability of lithium and  aluminum film loading were evaluated in the hydrogen loading system while comparing  to titanium as a benchmark. Unlike titanium and aluminum films where films  were in a solid state through the loading process, lithium has to be melted  into a liquid state to be loaded. The uptake of hydrogen by the films was  determined by Sievert's method, where the pressure drop recorded by the  Hydrogen Loading System was the measured pressure of hydrogen absorbed by the  film. All film loadings showed a pressure drop that corresponded to the  expected pressure drop from loading. The films were characterized after  loading to confirm hydrogen absorption and formation of hydride. Both lithium  and titanium demonstrated hydride formation while the aluminum did not.</p> <p>The pressure drops during loading  were compared to the Mintz-Bloch model. For some loadings in all materials,  there was good correlation between experimental loadings and Mintz-Bloch  models, primarily due to the hydride formation happening quickly. Differences  can be explained from the speed of the hydride reaction and thermal  decomposition of the hydride during loading. The Mintz-Bloch model further  confirmed that the aluminum did not form a hydride during loading.</p> <p>Lithium was demonstrated to be a  viable hydrogen loading substrate. The film was characterized to be lithium  hydride after hydrogen loading and its loading kinetics matched very well with  the Mintz-Bloch model. Aluminum was demonstrated to not be viable as a  hydrogen loading substrate as it requires significantly higher pressures,  beyond the allowed limits for tritium handling, to form a hydride and  permanently hold when exposed to atmosphere.</p>

<p dir="ltr">The accurate identification of flow regimes in multiphase flow systems is of paramount importance in many engineering applications. This thesis explores the significance of flow regime identification using neural networks, specifically employing a self-organizing map (SOM) algorithm. The focus of this research is on the determination of bubble void fraction probability density function (PDF) using local conductivity probe measurements. The thesis begins by providing an overview of the importance of flow regime identification in understanding and predicting the behavior of multiphase flows. Various flow regimes such as bubbly flow, slug flow, annular flow, and others, are discussed highlighting their distinct characteristics and implications for system performance. The self-organizing map is introduced as a powerful neural network technique capable of identifying and classifying different flow regimes based on input parameters obtained from local conductivity probe measurements. The SOM algorithm is explained in detail, emphasizing its ability to learn and adapt to complex patterns in the data. To validate the effectiveness of the proposed approach, experimental measurements of local conductivity probe signals were conducted in a multiphase flow system. The obtained data was used to train and optimize a self-organizing map for flow regime identification. The bubble void fraction probability density function was calculated based on the local time-averaged void fraction measurements from the droplet-capable conductivity probe (DCCP-4). The analysis of the PDF provides valuable insights into the distribution and characteristics of bubbles within the multiphase flow system. These insights can enhance the understanding of bubble behavior, droplet behavior, interfacial phenomena and overall system performance. The thesis concludes with the classification results along with an error analysis conducted to highlight potential discrepancies in the tested results. Additionally, future research directions and potential improvements in the flow regime identification methodology are outlined.</p>

<p dir="ltr">The estimation of local irradiation conditions is a complex and crucial task with significant implications for reactor safety, operation, and spent nuclear fuel management. This study aims to investigate the feasibility of using measurements of a limited number of nuclides taken at the time of discharge to infer local irradiation conditions. Specifically, the focus is on determining the local operating power, void fraction, and burnup. These factors are required to calculate the isotopic composition of discharged reactor assemblies. Existing methods often struggle with substantial uncertainties when estimating these local conditions, leading to inaccuracies in isotopic calculations. Therefore, markedly different, this research aims to establish a relationship between local conditions and isotopic measurements, benefiting from the low uncertainty associated with experimental isotopic measurements. To achieve this goal, a two-step approach is employed. First, a mathematical inference procedure is developed to correlate the isotopic composition of discharged fuel with the local irradiation conditions. Second, given a certain prediction accuracy, efforts are made to minimize the number of isotopic measurements required at the time of discharge. To do so, this work develops an inference algorithm employing a simplified depletion model of a single pin in a BWR assembly using SCALE Polaris module. Polaris module generates the virtual measurement of 29 nuclides including actinides and fission products with assumed power and void fraction histories provided to SCALE Polaris as inputs. Employing these virtual measurements, a similarity measure metric is employed to minimize the number of nuclides to estimate irradiation conditions, and the inference method used to estimate the irradiation conditions is the ordinary least squares method.</p>

No description available.

<p dir="ltr">Research on enhancing the plasma confinement characteristics in fusion reactors and tokamaks has focused heavily on Low-Z plasma facing components Be, BeO, and SiC in recent decades. Building reactors, reducing harmful effects, and creating materials resistant to radiation all depend on an understanding of the plasma material interactions. In nuclear reactors, material composition and properties are also influenced by an understanding of impurity interactions. This thesis aims to investigate the effects of varying sputtering rates and long-term plasma durability on structured materials sputtered by plasma under various situations. The majority of this research has been done on the sputtering of materials as it accelerates the degradation of materials. To understand the process of ion solid contacts, a thorough investigation of ions' interactions with target atoms is presented in this work. Monte Carlo (MC) simulation has been done in this entire research by using the transport of ions in matter (TRIM). The influence of ion energy (100–1000 eV) and ion incidence angle by deuterium ions has been simulated in this study. As expected, on one hand, sputtering yield, as a function of ion-energy peaks first and a sequential reduction afterword; on the other hand, as a function of ion-incidence angle shows sequential enhancement towards max value followed by sharp reduction afterwards. The simulated data have been compared with the relevant experimental data and very close agreements were observed. To investigate the behavior of ion energy loss in relation to ion range in the targets, distribution profiles associated with ion range, recoil, ionization, and phonons are developed. Deuterium accumulation and its impact on Be target also have been shown in this work. The sputtering yield of <a href="" target="_blank">BeD₂</a> is lowest when the D incident ion interacts with low percentage of D has been simulated as target. Gradually increasing the percentage of D as target results in higher yields.</p>

O tratamento de efluentes industriais é uma prática que vem se disseminando em ritmo acelerado, porque além de contribuir para reforçar a imagem pública, através do combate à poluição, ela traz vantagens econômicas para as empresas que podem reutilizar a água tratada do efluente em seus próprios processos. A técnica de tratamento estudada no presente trabalho é a que utiliza a oxidação/redução química destacando-se a utilização da radiação ionizante por meio de feixes de elétrons. Esta técnica utiliza um processo oxidativo avançado, gerando radicais altamente reativos que provocam a oxidação, redução, dissociação e degradação em compostos orgânicos e exercendo efeito letal nos microorganismos, protozoários e parasitas em geral. Neste trabalho desenvolveu-se um projeto conceituai e básico de uma unidade móvel de tratamento de efluentes utilizando radiação ionizante, fazendo com que a unidade se desloque até o ponto de tratamento, facilitando assim a logística. Em seguida, elaborou-se um estudo de viabilidade técnica e econômica permitindo dados consistentes sobre a capacidade e custo de processamento de efluentes e valores consolidados dos investimentos necessários para serem apresentados a órgãos financiadores para a construção de uma unidade móvel. Os resultados dos estudos demonstram que é viável tecnicamente a construção de uma unidade móvel, pois atende a legislação pertinente do Brasil, nos aspectos de Radioproteção e limite de transporte de carga. O custo unitário do processamento mostrou-se superior ao de uma unidade fixa em razão da diminuição da eficiência da interação da radiação incidente no efluente processado, devido à redução de energia do acelerador de elétrons e da disponibilidade de operação da unidade. / The treatment of industrial effluents is a practice that is disseminating in accelerated rhythm, of contributing to reinforce the public image, through the combat of the pollution, it brings economical advantages allowing the companies the reuse of the treated water in their own processes. The liquid effluent treatment technique studied in the present work is the one that uses the chemical oxidation/reduction standing out the use of the electron beam (e.b.) radiation. This technique uses an advanced oxidation process, generating radicals highly reagents that provoke the oxidation, reduction, dissociation and degradation in composed organic and exercising lethal effect in general in the microorganisms and parasites. In this work a conceptual and basic project of a movable unit of effluents treatment using electron beam radiation process was developed, in order that the unit moves until the treatment point, where the effluent is produced, facilitating the logistics. A technical and economical feasibility study was also elaborated allowing data on the capacity and cost of effluents processing to consolidate the values of the necessary investments to be presented to foundations organs for the construction of a movable unit. The results of the studies demonstrated that it is technically viable attending the pertinent legislation of Brazil, in the aspects of Radiation Protection and transport limit capacity. The unitary cost of the e.b. radiation processing in the movable unit was shown more expensive than in the fixed unit, the reason is the decrease of the efficiency of the interaction of the incident electrons in the effluent, due to the reduction of electron energy operation time of the unit.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais / Este trabalho apresenta o desenvolvimento de técnicas hidrometalúrgicos para o tratamento de licores gerados a partir de resíduos industriais da metalurgia extrativa do zinco. Um dos licores (ZnCu) contém teores significativos de zinco e cobre (29,6 g/L Zn e 37,4 g/L Cu) e o outro licor (ZnCd) contém elevados teores de zinco e cádmio (141 g/L Zn e 53,4 g/L Cd). A recuperação dos metais Zn e Cd, a partir da amostra ZnCd, foi realizada pela técnica de cementação. As variáveis de processo investigadas foram: temperatura, pH inicial do licor, tempo de reação e o excesso de pó de zinco metálico. Após a definição das melhores condições, foi obtida uma solução de sulfato de zinco com teor de 150 g/L de Zn e 0,005 g/L de Cd, passível de alimentar a etapa de eletrólise para a obtenção do zinco metálico. O cádmio metálico obtido apresentou pureza superior a 90% com uma recuperação de 99,9%. No estudo com a amostra ZnCu utilizou-se a técnica de extração por solventes (extração líquido-líquido). Foram realizados experimentos descontínuos e contínuos. Nos experimentos descontínuos, investigou-se as seguintes variáveis de processo: tipo e concentração do agente extratante, acidez da fase aquosa, relação volumétrica entre as fases e concentração do agente reextratante (solução de ácido sulfúrico). Os experimentos foram realizados em temperatura ambiente, (25 2oC) e velocidade de agitação de 500 rotações por minuto (rpm). Foram testados seis extratantes trocadores catiônicos. Três da classe dos extratantes ácidos (D2EHPA, IONQUEST801 e CYANEX272) e três da classe dos extratantes quelantes (LIX63, LIX984N e LIX612N-LV). Todos os extratantes apresentaram elevados fatores de separação, indicando alta potencialidade de obtenção dos metais zinco e cobre, separadamente, em elevada pureza. Com os extratantes D2EHPA, IONQUEST e CYANEX, os fatores de separação Zn/Cu foram 296, 323 e 361, respectivamente. Com o LIX612N-LV, obteve-se um fator de separação Cu/Zn 94, enquanto para o LIX63 e o LIX984N este fator foi de 62 e 37, respectivamente. Dentre os extratantes testados, foi selecionado o D2EHPA para o estudo das variáveis de processo e realização dos experimentos contínuos. O melhor resultado foi obtido com o D2EHPA 1 mol/L em pH de equilíbrio próximo de 2, em uma relação de fases A/O igual a 1 e tempo de contato de 10 minutos. Os ensaios de reextração foram realizados com solução de H2SO4. Os resultados mostraram que o cobre co-extraído, juntamente com o zinco, pode ser removido da fase orgânica através de uma etapa de lavagem utilizando solução diluída de ácido sulfúrico e o zinco reextraído com uma solução de H2SO4 mais concentrada (2 mol/L). Depois de selecionadas as melhores condições de processo, foram realizados cinco ensaios contínuos, até se atingir a condição ótima de separação dos metais Zn e Cu. Os experimentos de 1 a 4 foram realizados com uma solução preparada no laboratório, simulando o licor industrial. O experimento contínuo 5 foi realizado com a solução original, gerada na lixiviação do resíduo industrial, contendo 29,6 g/L Zn, 37,4 g/L Cu, 1,94 g/L Cd, 0,127 g/L Co e 0,100 g/L Ni. O experimento foi realizado nas mesmas condições operacionais do experimento 4, onde foi obtido o melhor resultado. O circuito de extração constou de 3 estágios de extração, 3 estágios de lavagem e 5 estágios de reextração. Neste experimento foi obtido um reextrato com 125 g/L Zn, 0,05 g/L Cu e teores de Cd, Co e Ni menores que 0,005 g/L. A concentração dos metais no rafinado foi de 28,6 g/L Cu, 0,49 g/L Zn, 1,48 g/L Cd, 0,080 g/L Ni e 0,098 g/L Co. / This paper presents a development of hydrometallurgic techniques for the treatment of liquors obtained from industrial residues generated in the zinc extractive metallurgy. One of the liquors (ZnCu) contains significant amounts of zinc and copper (29.6 g/L zn and 37.4 g/L Cu) and the other (ZnCd) containing high levels of zinc and cadmium (141 g/L Zn and 53.4 g/L Cd). The recovery of the Zn and Cd metals from the ZnCd sample was carried out using the cementation technique. The process variables investigated were: temperature, initial pH of the liquor, reaction time and the metallic zinc powder excess. After establishing the best conditions, a zinc sulphate solution containing 150 g/L of Zn and 0.005 g/L of Cd was obtained. This solution is capable of feeding the electrolysis stage in order to obtain metallic zinc. The level of purity of the metallic cadmium obtained by the cementation technique was higher than 90%, and the recovery rate was 99.9%. The separation of zinc and copper from the ZnCu sample was carried out using the solvent extraction technique. Non-continuous and continuous experiments were done. In the non-continuous experiment, the following process variables were investigated: type and concentration of the extractants, acidity of the aqueous phase, volume relation between the phases and the stripping agent concentration (sulphur acid solution). The experiments were carried out in a room temperature (25 2oC), and with an agitation of 500 rpm. Six cationic extractants were investigated - three acid extractants (D2EHPA, IONQUEST801 and CYANEX272) as well as three chelating extractants (LIX63, LIX984N and LIX612N-LV). All extractants presented a high separation factor and could be used in the separation process. The Zn/Cu separation factor obtained with D2EHPA, IONQUEST and CYANEX was 296, 323 and 361 respectively. The Cu/Zn separation factor obtained with LIX612N-LV was 94, whereas the one obtained for LIX63 and LIX984N was 62 and 37 respectively. Amongst the extractants tested, the D2EHPA was the one selected for the study of the variables of this process. The best result was attained with the D2EHPA 1 mol/L at an equilibrium pH near 2, and contact time of 10 minutes. The metal stripping was carried out with H2SO4. The results showed that the co-extracted copper may be scrubbed from the organic phase through a diluted sulphuric acid solution, and the zinc can be stripped with a more concentrated H2SO4 solution (2mol/L). Fifth continuous experiments were realized until an optimal condition for the separation of the metals Zn and Cu was achieved. The experiments from 1 to 4 were carried out with a solution prepared in a laboratory simulating the industrial liquor. Experiment 5, was carried out with the industrial liquor, in the same conditions of the experiment 4, which presented the best results. It was carried out in three extraction stages, three scrubbing stages and 5 stripping stages. In this experiment, a pregnant strip solution containing 125 g/L Zn, and 0.050 g/L Cu, with less than 0.005 g/L Cd, Co and Ni, from a solution containing 29.6 g/L Zn, 37.4 g/L Cu, 1.94 g/L Cd, 0.127 g/L Co and 0.100 g/L Ni was obtained. The concentration of the metals in the raffinate was 28.6 g/L Cu, 0.49 g/L Zn, 1.48 g/L Cd, 0.080 g/L Ni and 0.098 g/L Co.