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Tesis sobre el tema "Industrial solvent"

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Publicado: 18 de mayo de 2024

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1

Dalgleish, John Richard. "The effects of paint solvent exposure on submariners". Thesis, University of Newcastle Upon Tyne, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240861.

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2

Farshad, Ali A. "The relationship between occupational exposure, absorption and excretion of solvent vapours". Thesis, University of Newcastle Upon Tyne, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240981.

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3

Gibson, Jason. "Neurotoxicity of the Industrial Solvent 4-Methylcyclohexanemethanol: Involvement of the GABA Receptor". Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc799542/.

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A recent chemical spill of 4-Methylcyclohexanemethanol (4-MCHM) in West Virginia left 300,000 people without water. Officials claimed that this compound is not lethally toxic, but potentially harmful if swallowed or inhaled, and can cause eye and skin irritation. Sittig's Handbook of Toxic and Hazardous Chemical Carcinogens reports high exposures from skin contact or inhalation may cause damage to the heart, liver, kidneys, and lungs, and may result in death. However, no quantitative data seem to exist and no references can be found on neurotoxicity. We have investigated the neurotoxicity of 4-MCHM using mammalian nerve cell networks grown on microelectrode arrays. Network spontaneous activity from multiple units (range 48 – 120 per network) were used as the primary readout. Individual units were followed based on spike waveforms digitized at 40 kHz (Plexon MNAP system). Dose response curves show the effective inhibitory concentration at 50 percent decrease (EC50) to average 27.4 microM SD±6.17. However, in the presence of 40 microM bicuculline, a competitive GABAA antagonist, the EC50 shifts to 70.63uM SD ±4.3; implying that early, low concentration exposures to 4-MCHM involve GABA activation. Initial activity loss occurs without active unit loss (defined as 10 or more template threshold crossing per min), indicating functional interference with spike production. Full recovery has not been seen at concentrations above 130 microM, unless the culture was given bicuculline. Direct exposure to 400uM results in immediate, irreversible loss of spike production, followed by necrosis of glia and neurons.
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4

Oesterle, Matthew John. "Silver ion and solvent effects on polystyrene photochemistry". Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/27565.

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5

Alves, Carine Tondo. "Transesterificação de Óleos e Gorduras Residuais via rotas metílica e etílica utilizando o catalisador Aluminato de Zinco, em presença ou não de CO2 supercrítico". Universidade Federal da Bahia, 2012. http://repositorio.ufba.br/ri/handle/ri/23902.

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Neste estudo, o aluminato de zinco foi sintetizado através da reação de combustão e caracterizado de acordo com suas propriedades físicas e texturais. O catalisador foi utilizado na reação de transesterificação em condições subcríticas e supercríticas, via rotas metílica e etílica a partir de óleos e gorduras residuais (OGR). As condições experimentais utilizadas foram previamente estudadas através do acervo bibliográfico e fixadas em 2 horas de reação, razão molar de álcool:óleo 40:1, agitação mecânica de 700 rpm, razão de catalisador em peso com relação à quantidade inicial de óleo entre 1 e 10 % e temperatura de reação entre 60 e 200 ºC. O estudo da reação de transesterificação indicou resultados promissores para as duas metodologias utilizadas. Os resultados obtidos indicaram que o rendimento em ésteres aumentou significativamente em temperaturas amênas quando a razão de catalisador:óleo foi acrescida de 1 % para 5,5 % e 10 % de catalisador em relação à quantidade inicial de óleo para as duas metodologias avaliadas. Estes dados foram justificados pela possibilidade de formação de mais do que uma fase entre o óleo e o álcool em baixas temperaturas. Contudo, a influência desta razão decresceu à medida que se aumentou a temperatura de reação até 200 °C, sendo obtidos rendimentos em ésteres > 98 % em 30 minutos de reação em condições severas utilizando-se 1 % de catalisador e dióxido de carbono em estado supercrítico.
In this study, the zinc aluminate was synthesized by the combustion reaction and characterized according to their physical and textural properties. The catalyst was used in the transesterification reaction in supercritical and subcritical conditions, via methylic and ethylic routes from waste frying oils (WFO). The experimental conditions used were previously studied and fixed in 2 hours of reaction time, 40:1 of alcohol:oil molar ratio, 700 rpm of mechanical stirring, 1, 5.5 % and 10 % by weight of catalyst ratio and 60 to 200 º C of reaction temperature. The study of the transesterification reaction indicated promising results for both methodologies. The results indicated that the yield of esters at moderate temperatures significantly increased when the ratio of catalyst:oil was increased from 1 % to 5.5 % and 10 % of catalyst relative to the initial quantity of oil to the two methodologies evaluated. These data were substantiated by the possibility of forming more than one phase between the oil and the alcohol at low temperatures. However, the influence of this ratio is decreased as the reaction temperature increased to 200 ° C, were obtained > 98% of esters yields in 30 minutes of reaction under stringent conditions using 1 % catalyst and supercritical carbon dioxide.
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6

Benguerel, Elyse. "Solvent extraction of rhodium from chloride solutions in the presence of SnCl2 with Kelex 100tm". Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40321.

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The aim of this work was to devise and investigate a solvent extraction system for rhodium, from aqueous chloride solutions, having potential industrial applicability. The extractant investigated was Kelex 100, a commercially available derivative of 8-hydroxyquinoline. Ultimately, two different systems were developed. Both are based on an initial complexation reaction between the aqueous rhodium chloride complexes, (RhCl$ rm sb{6-n}(H sb2O) sb{n} rbrack sp{(3-n)-}$ and stannous chloride, referred to as the activation stage, but the two systems use a different Sn:Rh molar ratio. In both cases, the Rh-Sn complexes, either (Rh(SnCl$ sb3) sb5 rbrack sp{4-}$ or (RhCl$ rm sb3(SnCl sb3) sb3 rbrack sp{3-},$ respond well to extraction with Kelex 100. One of the main differences between the two systems is in the stripping medium which is used to transfer the rhodium from the loaded organic phase back into an aqueous phase. In the case of the high Sn:Rh ratio feeds, the stripping stage is based on sulfuric acid, whereas in the case of low Sn:Rh ratio feeds, the rhodium is stripped from the organic phase using a sulfite containing hydrochloric acid solution.
The two systems were characterized in terms of their equilibrium and kinetic behaviour during all three stages; activation, extraction, and stripping. Activation was found to proceed either at room temperature or at elevated temperatures and the above-mentioned expected Rh-Sn complexes were identified through $ sp{119}$Sn NMR and Raman spectroscopy. The extraction stage was found to be quantitative for rhodium and it was also found to be very rapid, with contact times of less than five minutes sufficient for rhodium extraction. The extraction mechanism was determined to be ion-pair formation with the protonated Kelex 100 molecules at a stoichiometry such that the overall charge in the organic phase is neutral, i.e., three Kelex 100 molecules for (RhCl$ rm sb3(SnCl sb3) sb3 rbrack sp{3-}$ and four for (Rh(SnCl$ sb3) sb5 rbrack sp{4-}.$
The stripping stages were the most problematic for both systems. In one case, the system was eventually abandoned due to limitations in the amount of rhodium which could be transferred to the sulfuric acid strip solution. For the low Sn:Rh system, reasonable rhodium transfer and concentration level were obtained. The rhodium complex in the strip solution has been proposed to be (RhCl$ rm sb2(SO sb3) rbrack sp{3-}.$ Strip solutions up to $4 times10 sp{-2}$M in rhodium concentration have been produced, from initial feed solutions having a rhodium concentration of about $4 times10 sp{-3}$M. Preliminary flowsheets are proposed for further refinement for both systems, although only the second system, the low Sn:Rh ratio system which uses sulfite stripping, is advocated for further development.
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7

Sarkar, Lovely. "Physico-chemical studies on various interactions in some industrial solvent systems and viscous synergy and antagonism prevailing in liquid mixtures". Thesis, University of North Bengal, 2010. http://hdl.handle.net/123456789/1418.

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8

Canizella, Rodnei [UNESP]. "Análise das perdas na produção contínua de extração de óleo de soja: estudo de caso no método de extração por solvente". Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/93012.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
As atividades de uma indústria com o sistema de produção contínua possuem características próprias dependendo do processo a que se dispõe a transformar uma matéria-prima, por isso este trabalho trata de analisar as perdas na produção contínua de extração de óleo de soja por solvente, apresentando a descrição do processo e as principais indicadores de desempenho, propondo sugetões de monitoramento para melhoria dos resultados. Essa abordagem é feita comparando-se resultados propiciados por alguns autores da área com dados da área com dados levantados de uma empresa no Brasil em dois períodos distintos, incluindo análise de evolução da planta, onde a alta gerência monitora a produtividade e a qualidade dos produtos, e trata as perdas no ambiente de transformação como consumo de solvente utilizado para extração do óleo de soja e consumo de combustível para a geração de energia térmica. Conclui-se que a indústria de extração de óleo vegetal, possui diversas variáveis de controle pelo conjunto de operações necessárias à transformação, ressaltando neste caso a perda de energia térmica como prioridade de atitudes de melhorias. Dado que a tendência de aumento da capacidade de processamento de soja é evidente, pela perspectiva de crescimento da produção de soja no Brasil, deve ser considerado neste contexto, o investimento em conhecimento para as pessoas exercerem as atividades operacionais em perfeita sincronia com as informações que ocorrem no processo, garantindo o objetivo da organização de minimização das perdas, e consequente aumento do lucro e crescimento
The activities of the industry with a continuous production system have their own characteristics depending on the process that is willing to turn a raw material, so this work is to analyzed the losses in the continuous production of soybean oil extraction solvent, presenting the description of the process and key performance indicators and propose suggestions for the improvement of monitoring results. This approach is made comparing the results obtained by some authors in the field with data collected from a company in Brazil in two distinct periods, including examination of the plant, where top management monitors productivity and product quality, and treats losses the environment of use as processing solvent used to extract the soybean oil and fuel to generate heat energy. It is concluded that the industry of oil extraction plant has several control variables the operations required for processing, emphasizing in this case the loss of thermal energy as priority actions for improvements. Since the trend of increased processing capacity of soybean is evident from the perspective of growth of soybean production in Brazil, should be considered in this context, investment in knowledge for people to exercise operational activities in perfect synchrony with the information occur in the process, ensuring the organization's goal of minimizind losses, and consequent increase in profit and growth
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9

Canizella, Rodnei. "Análise das perdas na produção contínua de extração de óleo de soja : estudo de caso no método de extração por solvente /". Bauru : [s.n.], 2012. http://hdl.handle.net/11449/93012.

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Resumo: As atividades de uma indústria com o sistema de produção contínua possuem características próprias dependendo do processo a que se dispõe a transformar uma matéria-prima, por isso este trabalho trata de analisar as perdas na produção contínua de extração de óleo de soja por solvente, apresentando a descrição do processo e as principais indicadores de desempenho, propondo sugetões de monitoramento para melhoria dos resultados. Essa abordagem é feita comparando-se resultados propiciados por alguns autores da área com dados da área com dados levantados de uma empresa no Brasil em dois períodos distintos, incluindo análise de evolução da planta, onde a alta gerência monitora a produtividade e a qualidade dos produtos, e trata as perdas no ambiente de transformação como consumo de solvente utilizado para extração do óleo de soja e consumo de combustível para a geração de energia térmica. Conclui-se que a indústria de extração de óleo vegetal, possui diversas variáveis de controle pelo conjunto de operações necessárias à transformação, ressaltando neste caso a perda de energia térmica como prioridade de atitudes de melhorias. Dado que a tendência de aumento da capacidade de processamento de soja é evidente, pela perspectiva de crescimento da produção de soja no Brasil, deve ser considerado neste contexto, o investimento em conhecimento para as pessoas exercerem as atividades operacionais em perfeita sincronia com as informações que ocorrem no processo, garantindo o objetivo da organização de minimização das perdas, e consequente aumento do lucro e crescimento
Abstract: The activities of the industry with a continuous production system have their own characteristics depending on the process that is willing to turn a raw material, so this work is to analyzed the losses in the continuous production of soybean oil extraction solvent, presenting the description of the process and key performance indicators and propose suggestions for the improvement of monitoring results. This approach is made comparing the results obtained by some authors in the field with data collected from a company in Brazil in two distinct periods, including examination of the plant, where top management monitors productivity and product quality, and treats losses the environment of use as processing solvent used to extract the soybean oil and fuel to generate heat energy. It is concluded that the industry of oil extraction plant has several control variables the operations required for processing, emphasizing in this case the loss of thermal energy as priority actions for improvements. Since the trend of increased processing capacity of soybean is evident from the perspective of growth of soybean production in Brazil, should be considered in this context, investment in knowledge for people to exercise operational activities in perfect synchrony with the information occur in the process, ensuring the organization's goal of minimizind losses, and consequent increase in profit and growth
Orientador: Manoel Henrique Salgado
Coorientador: José de Souza Rodrigues
Banca: Rogério Andrade Flauzino
Banca: Vagner Cavenaghi
Mestre
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10

Barman, Biraj Kumar. "Investigation of diverse interactions and inclusion complexation in different environment by physicochemical methodology". Thesis, University of North Bengal, 2018. http://ir.nbu.ac.in/handle/123456789/2622.

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11

Fasol, Silvia. "Exploring the potential of transaminases in aqueous organic solvent solutions through protein engineering: a resource to optimise the synthesis of chiral amines". Thesis, KTH, Skolan för bioteknologi (BIO), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-163680.

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12

Gouvea, Ligiane Rios. "Recuperação de zinco, cádmio e cobre de licores sulfúricos provenientes de resíduos industriais da metalurgia extrativa do zinco". CNEN - Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte, 2008. http://www.bdtd.cdtn.br//tde_busca/arquivo.php?codArquivo=100.

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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.
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Pradhan, Rajendra. "Molecular interactions in mixtures of some industrially important solvents: a physico-chemical study". Thesis, University of North Bengal, 2018. http://ir.nbu.ac.in/handle/123456789/2698.

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Ramirez, Cadavid David A. "Development of Processes for the Extraction of Industrial Grade Rubber and Co-Products from the Roots of Taraxacum kok-saghyz (TK)". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1512060296142347.

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15

Eshraghi, Alireza. "Prediction of exposure to industrial solvents". Thesis, London South Bank University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312998.

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Martins, Marcelo Natan. "Aprimoramento da metodologia de encapsulamento com poliestireno visando a escala industrial". Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/2385.

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A técnica de microencapsulamento consiste em englobar um núcleo com o material que se deseja proteger com uma casca sólida que tem a finalidade de proteger o núcleo. A técnica de evaporação de solvente consiste em realizar duas emulsões, contendo o núcleo que se deseja encapsular, o polímero que formará a cápsula dissolvido em solvente e um meio de dispersão. Para o processo, a modificação de parâmetros e condições de processo são capazes de aumentar a eficiência do microencapsulamento. Foram produzidas microcápsulas de poliestireno contendo água deionizada com o objetivo de analisar o efeito da relação núcleo cápsula, temperatura de evaporação, presença de cloreto de sódio e surfactante na eficiência do processo de microencapsulamento, quando comparados a uma amostra padrão. Adicionalmente, as amostras foram caracterizadas por microscopia eletrônica de varredura (MEV) e análise termogravimétrica (TG). Foi encontrado que a relação núcleo: cápsula ideal para a produção de microcápsulas é de 2:1, com eficiência de 61,47 %. A análise termogravimétrica indicou também que a relação 2:1 apresentava melhor eficiência pois continha uma maior quantidade de material do núcleo. As imagens de MEV mostraram que a microcápsula formada possui superfície lisa. A adição de tensoativo e a redução da temperatura de evaporação aumentaram a eficiência para 76,83 % e 79,25 % respectivamente.
The microencapsulation technic consist in envelop a core with the material to protect by a solid shell that protects the core for the external environment.The solvent evaporation techtnic consist into two emulsion, the core that wants to be encapsulated, the polimers for the shell solved into a organic solvent and a dispesion media. For the process, the modification of process parameters are able to improve the yeld of the microencapsulation. It was produced polystyrene microcapsules with deionized water to evaluate the effect of core: shell ratio, evaporation temperature, the presence of sodium chloride and the surfactant in the efficiency microencapsulation process, when compared to a standard sample. Additionally, samples were characterized by scanning electron microscopy (SEM) and thermal gravimetric analysis (TG). It was found that the ideal core:shell ratio for the production of microcapsules is 2: 1, with 61.47% of yelding. Thermogravimetric analysis also indicated that the 2:1 ratio had better efficiency since it contained a larger amount of the core material. The SEM images showed that the formed microcapsule has smooth surface. The addition of surfactant and reducing the evaporation temperature increased the efficiency of 76.83% and 79.25% respectively.
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17

Mulchandani, Ashok K. "Biosynthesis of industrial solvents in a cell-retention fermentor". Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=72071.

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The continuous culture performance of a custom designed cell-retention (CR) bioreactor prototype was investigated for the acetone - butanol - ethanol (A-B-E) fermentation by Clostridium acetobutylicum.
A mathematical model for the kinetics of the A-B-E fermentation was developed reflecting the biochemical pathway and culture behaviour. Dynamic and steady-state behaviour of C. acetobutylicum in the CR bioreactor was simulated on the computer and experimentally tested.
In an operational mode with a total cell-retention, a steady-state operation of the bioreactor was predicted up to 52 g/L of sugar in the feed stream. The sugar was completely utilized. Experiments confirmed the suitability of the model and its predictions including the independence of the key process parameter concentrations from the dilution rate.
For the feed sugar concentration in excess of 52 g/L an unsteady-state fermentation system behaviour was predicted by computer simulation and an oscillatory performance of the bioreactor was observed experimentally. Additional bleeding of the whole cell broth from the fermentor resulted in stabilizing the bioreactor performance.
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18

Pradhan, Prasanna. "Studies on solution properties prevailing in some industrial solvents by physico-chemical methods". Thesis, University of North Bengal, 2009. http://hdl.handle.net/123456789/1318.

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19

Hernandez, Ochoa Leon Raul. "Substitution de solvants et matières actives de synthèse par un combiné «solvant/actif » d'origine végétale". Phd thesis, Toulouse, INPT, 2005. http://oatao.univ-toulouse.fr/7399/1/hernandez_ochoa.pdf.

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L'hydrodistillation est la principale méthode permettant d'obtenir des huiles essentielles à partir de plantes aromatiques. Traditionnellement, l'eau correspond au solvant employé lors du processus d'hydrodistillation. Cependant, dans la Co-hydrodistillation les esters éthyliques des acides gras présentent une alternative en tant que solvants d'extraction. Ces deux processus ont été comparés comme méthodes d'extraction des huiles essentielles des plantes sélectionnées pour leurs propriétés biologiques: Aunée (Inula helenium L.), Carvi (Carum carvi L.), Origan de Crète (Origanum dictamnus), Origan (Origanum vulgaire), Acore (Acorus calamus). Les composés volatils isolés ont été analysés par chromatographie en phase gazeuse couplée à un spectromètre de masse (GC-MS) et les résultats obtenus ont été comparés. Des différences significatives ont été trouvées dans la composition quantitative et qualitative des extraits obtenus. Le mélange des huiles essentielles et des esters éthyliques d'acides gras peut trouver une application dans l'industrie phytosanitaire.
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20

Fadhel, Ali Zuhair. "Designing for sustainability: applications of tunable solvents, switchable solvents, and catalysis to industrial processes". Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39646.

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The focus of this research was to improve the sustainability of various processes by employing tunable solvents, switchable solvents, and catalysis. In Chapter 2, we report applications of tunable solvents to metal and enzyme catalyzed reactions of hydrophobic substrates. Tunable solvents are defined as solvent that change properties rapidly but continuously upon the application of an external physical stimulus and we utilize these solvents to couple homogeneous reactions with heterogeneous separations. We developed organic-aqueous tunable solvents that utilize propane for efficient phase separation at moderate pressures around 1 MPa; for example the water contents in the propane-expanded THF is 3 wt% at 0.8MPa at 30°C. Also, we extended the use of CO2-organic-aqueous tunable solvents to a pharmaceutically-relevant reaction--the hydroformylation of p-methylstyrene. The homogeneous reactions provide fast rates with excellent yields. At 60°C, the reaction reaches completion after 180 minutes with 95% branched aldehyde yield. The CO2-induced heterogeneous separation of the product from the catalyst provides an efficient and simple way to remove 99% of the product, to retain 99.9% of catalyst, and to recycle the Rh-TPPMS catalyst for five consecutive reactions. In chapter 3, we investigated the use of reversible ionic liquids (RevILs) for synthesis of nanoparticles. RevILs are formed by the reversible reaction of compounds with basic nitrogen functionalities (molecular liquid) with CO2 at ambient pressure to form a liquid salt (ionic liquid). We demonstrated that RevILs form microemulsions that can be switched-on by bubbling CO2 and switched-off by heating. These microemulsions solubilize ionic compounds such as chloroauric acid. We utilized these microemulsions as a template for controlled synthesis of gold nanoparticles. With 2-component RevILs, [TMBGH]+[O2COCH3]-/N-propyl-octylsulfonamide/hexane were used to form particles in the size range of 6-20 nm with an average particles size of 11.4±3.3. With 1-component RevILs, (3-aminopropyl)-tripropylsilane was used to prepare semi-spherical gold particles with an average size of about 20nm. The 1-component RevILs systems provide a simpler method to form microemulsions when compared to the 2-componenet RevILs systems since they eliminate the need for alcohols and surfactants. In chapter 4, we developed a catalyst that efficiently decomposes hydrazine to selectively produce ammonia. This enables the use of the chemical propulsion hydrazine for electric propulsion as well. We prepared nickel, copper, cobalt, ruthenium, rhodium, and iridium nanoparticles that were supported on silica and we tested these silica-supported metals for the decomposition of hydrazine. To study the catalytic activity, we designed and constructed a continuous flow reactor. The results show that nano-nickel supported on silica is the most active and selective catalyst with 100% conversion of hydrazine and 94±3% yield of ammonia.
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21

TRAMELLI, LORENZA. "RECUPERO DI COMPOSTI NATURALI AD ALTO VALORE AGGIUNTO DA SCARTI DELL' INDUSTRIA AGRO - ALIMENTARE". Doctoral thesis, Università Cattolica del Sacro Cuore, 2009. http://hdl.handle.net/10280/541.

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La presente ricerca ha lo scopo di sottolineare l'importanza degli antiossidanti naturali negli ultimi anni. Recenti studi hanno dimostrato l'importanza dei sottoprodotti della vinificazione in quanto particolarmente ricchi di composti fenolici. I fenoli possono essere recuperati da scarti (diminuendo il loro effetto inquinante) e usati come antiossidanti naturali in sostituzione di quelli chimici in sistemi alimentari per aumentare la shelf life.
The present research is aimed to underline the increasing importance that natural antioxidants have been gaining in the last years. Recent investigations have stressed the importance of vinification by-products as plant materials particularly rich in phenols. Phenols could be recovered by wastes (diminishing their pollutant effect) and used as natural antioxidant instead of chemical ones in food systems to extend the shelf life.
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22

TRAMELLI, LORENZA. "RECUPERO DI COMPOSTI NATURALI AD ALTO VALORE AGGIUNTO DA SCARTI DELL' INDUSTRIA AGRO - ALIMENTARE". Doctoral thesis, Università Cattolica del Sacro Cuore, 2009. http://hdl.handle.net/10280/541.

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La presente ricerca ha lo scopo di sottolineare l'importanza degli antiossidanti naturali negli ultimi anni. Recenti studi hanno dimostrato l'importanza dei sottoprodotti della vinificazione in quanto particolarmente ricchi di composti fenolici. I fenoli possono essere recuperati da scarti (diminuendo il loro effetto inquinante) e usati come antiossidanti naturali in sostituzione di quelli chimici in sistemi alimentari per aumentare la shelf life.
The present research is aimed to underline the increasing importance that natural antioxidants have been gaining in the last years. Recent investigations have stressed the importance of vinification by-products as plant materials particularly rich in phenols. Phenols could be recovered by wastes (diminishing their pollutant effect) and used as natural antioxidant instead of chemical ones in food systems to extend the shelf life.
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23

Elson, John L. "Expert and novice performance in an industrial engineering scaled world simulation". Columbus, Ohio : Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1067371218.

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Thesis (Ph. D.)--Ohio State University, 2003.
Title from first page of PDF file. Document formatted into pages; contains xi, 230 p.; also includes graphics (some col.). Includes abstract and vita. Advisor: Clark Mount-Campbell, Dept. of Industrial, Welding and Systems Engineering. Includes bibliographical references (p. 224-230).
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24

Abío, Roig Ignasi. "Solving hard industrial combinatorial problems with SAT". Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/117608.

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The topic of this thesis is the development of SAT-based techniques and tools for solving industrial combinatorial problems. First, it describes the architecture of state-of-the-art SAT and SMT Solvers based on the classical DPLL procedure. These systems can be used as black boxes for solving combinatorial problems. However, sometimes we can increase their efficiency with slight modifications of the basic algorithm. Therefore, the study and development of techniques for adjusting SAT Solvers to specific combinatorial problems is the first goal of this thesis. Namely, SAT Solvers can only deal with propositional logic. For solving general combinatorial problems, two different approaches are possible: - Reducing the complex constraints into propositional clauses. - Enriching the SAT Solver language. The first approach corresponds to encoding the constraint into SAT. The second one corresponds to using propagators, the basis for SMT Solvers. Regarding the first approach, in this document we improve the encoding of two of the most important combinatorial constraints: cardinality constraints and pseudo-Boolean constraints. After that, we present a new mixed approach, called lazy decomposition, which combines the advantages of encodings and propagators. The other part of the thesis uses these theoretical improvements in industrial combinatorial problems. We give a method for efficiently scheduling some professional sport leagues with SAT. The results are promising and show that a SAT approach is valid for these problems. However, the chaotical behavior of CDCL-based SAT Solvers due to VSIDS heuristics makes it difficult to obtain a similar solution for two similar problems. This may be inconvenient in real-world problems, since a user expects similar solutions when it makes slight modifications to the problem specification. In order to overcome this limitation, we have studied and solved the close solution problem, i.e., the problem of quickly finding a close solution when a similar problem is considered.
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25

Llamas, Zogbi Valentina Maria. "Towards an agile methodology for industrial problem solving". Phd thesis, Toulouse, INPT, 2017. http://oatao.univ-toulouse.fr/19421/1/LLAMAS_ZOGBI_Valentina_Maria.pdf.

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In order to survive to the unstable and highly changing market-place, modern organisations need to adapt their business processes to be more agile. Such is, particularly, the case of problem solving processes. Problem solving is a key activity that companies perform on a daily basis to improve quality and to obtain sustainable and continuous improvement. Such processes are built following standard rigid frameworks as Plan, Do, Check, Act (PDCA), Define, Measure, Analyse, Improve, Control (DMAIC), or 8 Disciplines (8D)/ 9 Steps (9S). In these methods, the generalization and reuse of knowledge is facilitated by standardization. However, it is sometimes difficult to react to unexpected events due to over-constrained standards. Then, a need arises to define a problem solving process sufficiently structured but not over constrained by standards, which can be reconfigured and adapted to unexpected situations, and that is based on experience feedback principles. This thesis work describes a proposition of an agile problem solving process driven by the reuse of experiences and knowledge. For this purpose, based on Case-Based Reasoning (CBR) principles, the complete lifecycle of an agile problem solving process is proposed. Following the five steps that compose the agile lifecycle, the agile process can be defined, executed and stored in a dedicated knowledge and experience base. An application of the model to a specific problem solving process of a surface treatment company is presented. The process is analysed, deploying the complete agile lifecycle. It is shown how the standard problem solving method used within the company could become more agile through the application of our method.
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26

Souza, Ariane Gaspari Oliveira. "Recuperação de óxido de escândio de alta pureza de resíduos industriais da cadeia de produção do níquel". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-22082016-110903/.

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O Escândio é um elemento terra rara, utilizado principalmente em ligas de alumínio, células combustíveis de óxido sólido e na produção de lâmpadas de haletos metálicos. Apesar de ser o 31° elemento mais abundante na crosta terrestre, raramente é encontrado concentrado na crosta terrestre, e sua produção é sempre associada ao processamento de outros minerais na forma de um subproduto, ou a recuperação de sucata. Minérios de Níquel podem conter teores de Sc variando de 50 a 350ppm e resíduos gerados durante seu processamento pode concentrar o Sc acima de 1000ppm. A recuperação do Escândio de um resíduo da cadeia de produção do Níquel foi estudada, de modo a obter um óxido com pureza acima de 99,0% para aplicações industriais. O resíduo utilizado é um precipitado, na forma de hidróxido, e contém principalmente Fe, Cu, Ni e Co, sendo o teor de Escândio em base seca aproximadamente 1000ppm. O processo de recuperação proposto consiste na lixiviação atmosférica do resíduo, precipitação seletiva para concentração do escândio e extração por solventes. A lixiviação atmosférica em meio sulfúrico 2,0mol.L-1 a 70°C permitiu a recuperação de 92,5% do Escândio contido no resíduo. Entretanto, não foi seletiva, lixiviando também parte dos demais metais presentes. Após a lixiviação para concentrar o Escândio, antes da extração por solventes, foi realizada uma precipitação com NaOH. O intuito foi precipitar o Fe, principal contaminante presente no lixiviado, entretanto ocorreu a co-precipitação de 95,5% do Sc junto a 65,6% Fe em pH 2,0. O precipitado representou uma concentração do Escândio do resíduo em 5,6 vezes. Esse concentrado de Escândio obtido foi dissolvido em solução de H2SO4 para recuperação do Escândio por extração por solventes. O extrante escolhido foi o Cyanex 923, uma mistura de óxidos alquil-fósfinicos. O mecanismo de extração do Sc pelo Cyanex 923 observado foi a solvatação e a estequiometria da reação 1:2. Foi observado um aumento na extração do Sc com o aumento da concentração de H+. O processo de extração do Sc com o Cyanex 923 é exotérmico, sendo favorecido a temperatura ambiente. O teor de Fe na solução aquosa antes da extração é 35 vezes maior que o Escândio, e apesar do Cyanex 923 ser mais seletivo para o Sc do que para o Fe, parte do Fe é co-extraído. O Fe co-extraído foi removido da fase orgânica por meio de uma lavagem com H2SO4 3mol.L-1 com uma perda de Sc de 1,3%. A reextração do Sc na fase orgânica não foi efetiva utilizando ácidos fortes devido a formação de um complexo estável. Foi utilizado ácido oxálico, técnica consolidada para reextração de terras raras, para recuperação do Sc da solução orgânica e a recuperação do Sc foi de 84,3% para uma solução com 4,0% de ácido oxálico. O oxalato de Sc precipitado foi recuperado por filtração e calcinado a 600°C. O óxido obtido apresentou pureza mínima de 99,0%.
Scandium is a rare earth element, used mainly in special aluminum alloys, SOFC\'s and metal halide lamps production. Despite of being the 31st element more abundant in Earth\'s Crust, it is rarely found concentrated in ores, and its production is always related to other minerals processing as a by-product or scrap recovering. Scandium content in Nickel ore may vary between 50 and 350ppm and residues produced during its processing can concentrate Sc above 1000ppm. Scandium recovery from a residue of Nickel processing was studied in order to obtain an oxide with purity higher than 99,0% for industrial applications. The residue used is a hydroxide precipitate, which contains mainly Fe, Cu, Ni and Co, Sc content is around 1000ppm (dry basis). The recovery process proposed consists in atmospheric leaching of the residue, selective precipitation to concentrate the Scandium and solvent extraction. The atmospheric leaching in sulfuric acid 2,0mol.L-1 at 70°C allowed the recovery of 92,5% of the Scandium present in the residue. However it was not selective and part of the other metals present in the residue were also leached. After leaching, in order to concentrate the Sc before solvent extraction, a precipitation with NaOH was performed. The initial aim was to precipitate the Iron - main contaminant present in the leach liquor - nevertheless it occurred the co-precipitation of 95,5% of the Sc besides 65,6% of Fe in pH 2,0. The precipitantion represented a concentration of the Sc in the residue of 5,6 times. The Scandium concentrate obtained was dissolved in a sulfuric acid solution to Sc recovery by solvent extraction. The extractant selected was Cyanex 923, a mixture of alkyl-phosphinic oxides. The mechanism of extraction of Scandium observed was solvation and reaction stechiometry was 1:2. It was observed an increase in Sc extraction rates by increasing the concentration of H+. The extraction of Scandium with Cyanex 923 is exothermic, and favorable at room temperature. The Iron content in aqueous solution before extraction is 35 times higher than that of Scandium, and even though Cyanex 923 being more selective for Sc than Fe, part of the Fe is co-extracted. The Fe co-extracted was removed of the organic phase by H2SO4 3mol.L-1 scrubbing with a Sc loss of 1,3%. The stripping of Scandium from organic phase was not accomplished by using strong acids due to formation of a stable complex. Afterwards, it was used oxalic acid - a technique consolidated for rare earths stripping - and the Sc recovery of organic phase was 84,3% with a solution of 4,0% oxalic acid. The Scandium oxalate precipitated was recovered by filtration and calcinated at 600°C. The Scandium oxide obtained presented 99,0% minimum purity.
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27

Jain, Pramod. "APPROXIMATE METHODS FOR SOLVING FLOWSHOP PROBLEMS". MSSTATE, 2005. http://sun.library.msstate.edu/ETD-db/theses/available/etd-11072005-155525/.

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The flow shop scheduling problem is a classical combinatorial problem being studied for years. The focus of this research is to study two variants of the flow shop scheduling problem in order to minimize makespan by scheduling n jobs on m machines. A solution approach is developed for the modified flow shop problem with due dates and release times. This algorithm is an attempt to contribute to the limited literature for the problem. Another tabu search-based solution approach is developed to solve the classical flow shop scheduling problem. This meta-heuristic (called 3XTS) allows an efficient search of the neighboring solutions leading to a fast solution procedure. Several control parameters affecting the quality of the algorithm are experimentally tested, and certain rules are established for different problem instances. The 3XTS is compared to another tabu search method (that seems to be a champion) in terms of solution quality and computation time.
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28

Sivaswamy, Swetha. "Industrial applications of principles of green chemistry". Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44776.

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Cross-linked polyethylene has higher upper use temperature than normal polyethylene and is used as an insulating material for electricity carrying cables and hot water pipes. The most common method of inducing crosslinks is by reaction with silanes. After incorporation of silanes into polyethylene and upon hydrolysis with ambient moisture or with hot water, Si-O-Si crosslinks are formed between the various linear polyethylene chains. Industrially, this reaction is performed routinely. However, the efficiency of this reaction with respect to the silane is low and control of product distribution is difficult. A precise fundamental understanding is necessary to be able to manipulate the reactions and thus, allow for the facile processing of the polymers. Hydrocarbon models of polymers - heptane, dodecane - are being used to study this reaction in the laboratory. For the reaction, vinyltrimethoxysilane is used as the grafting agent along with di-tert-butyl peroxide as the radical initiator. MALDI, a mass spectrometric technique is used for the analysis of the product distribution after work-up. Advanced NMR techniques (COSY, HSQC, DEPT, APT, HMBC) are being conducted on the grafted hydrocarbon compounds to gain an in-depth understanding of the mechanism and regiochemistry of the grafting reaction. Scalable and cost effective methods to capture CO2 are important to counterbalance some of the global impact of the combustion of fossil fuels on climate change. The main options available now include absorption, adsorption and membrane technology. Amines, especially monoethanolamine, have been the most commercialized technology. However, it is not without disadvantages. House et al have investigated the energy penalty involved in the post-combustion CO2 capture and storage from coal-fired power plants and found that 15-20% reduction in the overall electricity usage is necessary to offset the penalty from capturing and storing 80% of United States coal fleet's CO2 emssions1. Novel non-aqueous amine solvents, developed by the Eckert Liotta group, react with CO2 to form ionic liquids. The ionic liquids readily desorb CO2 upon heating, regenerating the reactive amines and this cycle can be carried out multiple times. An iterative procedure is being adopted to develop amine solvents for CO2 capture. Thermodynamic information like reversal temperature and boiling point of the solvents are collected; they are then used to formulate structure property relationships which allow for new molecules to be engineered. On reaction with CO2, there is a sharp increase in viscosity which is unfavorable from a processing standpoint. Many approaches to mitigate and control viscosity are being studied as well. 1House et al, Energy Environ Sci, 2009, 2, 193-205
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29

Engelsöy, Julius. "Optimal Allocation of Hardware in Industrial FEM Problem-Solving". Thesis, KTH, Matematik (Inst.), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-147982.

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This thesis aims to solve the problem of optimizing the allocation of hardware in industrial FEM problem-solving|a problem faced by, e.g., truck manufacturer Scania, which has requested this thesis and has provided some relevant data. The objective function to be minimized is taken to be the total processing time of a given FEM job distribution. Constraints include the available hardware and the number of accessible license tokens - the latter being the "currency" required to run the problem-solving software. The optimization problem is nonlinear and nonconvex and ought to be solved by use of a suitable algorithm. While the focus of this thesis is on modeling and problem formulation, a search for a global optimal solution was performed by use of MATLAB R. It is concluded that although the model and problem formulation include several areas of improvement, this thesis may hopefully contribute to streamlining Scania's FEM problem-solving process.
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30

Chai, Qinqin. "Computational methods for solving optimal industrial process control problems". Thesis, Curtin University, 2013. http://hdl.handle.net/20.500.11937/1227.

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In this thesis, we develop new computational methods for three classes of dynamic optimization problems: (i) A parameter identification problem for a general nonlinear time-delay system; (ii) an optimal control problem involving systems with both input and output delays, and subject to continuous inequality state constraints; and (iii) a max-min optimal control problem arising in gradient elution chromatography.In the first problem, we consider a parameter identification problem involving a general nonlinear time-delay system, where the unknown time delays and system parameters are to be identified. This problem is posed as a dynamic optimization problem, where its cost function is to measure the discrepancy between predicted output and observed system output. The aim is to find unknown time-delays and system parameters such that the cost function is minimized. We develop a gradient-based computational method for solving this dynamic optimization problem. We show that the gradients of the cost function with respect to these unknown parameters can be obtained via solving a set of auxiliary time-delay differential systems from t = 0 to t = T. On this basis, the parameter identification problem can be solved as a nonlinear optimization problem and existing optimization techniques can be used. Two numerical examples are solved using the proposed computational method. Simulation results show that the proposed computational method is highly effective. In particular, the convergence is very fast even when the initial guess of the parameter values is far away from the optimal values.Unlike the first problem, in the second problem, we consider a time delay identification problem, where the input function for the nonlinear time-delay system is piecewise-constant. We assume that the time-delays—one involving the state variables and the other involving the input variables—are unknown and need to be estimated using experimental data. We also formulate the problem of estimating the unknown delays as a nonlinear optimization problem in which the cost function measures the least-squares error between predicted output and measured system output. This estimation problem can be viewed as a switched system optimal control problem with time-delays. We show that the gradient of the cost function with respect to the unknown state delay can be obtained via solving a auxiliary time-delay differential system. Furthermore, the gradient of the cost function with respect to the unknown input delay can be obtained via solving an auxiliary time-delay differential system with jump conditions at the delayed control switching time points. On this basis, we develop a heuristic computational algorithm for solving this problem using gradient based optimization algorithms. Time-delays in two industrial processes are estimated using the proposed computational method. Simulation results show that the proposed computational method is highly effective.For the third problem, we consider a general optimal control problem governed by a system with input and output delays, and subject to continuous inequality constraints on the state and control. We focus on developing an effective computational method for solving this constrained time delay optimal control problem. For this, the control parameterization technique is used to approximate the time planning horizon [0, T] into N subintervals. Then, the control is approximated by a piecewise constant function with possible discontinuities at the pre-assigned partition points, which are also called the switching time points. The heights of the piecewise constant function are decision variables which are to be chosen such that a given cost function is minimized. For the continuous inequality constraints on the state, we construct approximating smooth functions in integral form. Then, the summation of these approximating smooth functions in integral form, which is called the constraint violation, is appended to the cost function to form a new augmented cost function. In this way, we obtain a sequence of approximate optimization problems subject to only boundedness constraints on the decision variables. Then, the gradient of the augmented cost function is derived. On this basis, we develop an effective computational method for solving the time-delay optimal control problem with continuous inequality constraints on the state and control via solving a sequence of approximate optimization problems, each of which can be solved as a nonlinear optimization problem by using existing gradient-based optimization techniques. This proposed method is then used to solve a practical optimal control problem arising in the study of a real evaporation process. The results obtained are highly satisfactory, showing that the proposed method is highly effective.The fourth problem that we consider is a max-min optimal control problem arising in the study of gradient elution chromatography, where the manipulative variables in the chromatographic process are to be chosen such that the separation efficiency is maximized. This problem has three non-standard characteristics: (i) The objective function is nonsmooth; (ii) each state variable is defined over a different time horizon; and (iii) the order of the final times for the state variable, the so-called retention times, are not fixed. To solve this problem, we first introduce a set of auxiliary decision variables to govern the ordering of the retention times. The integer constraints on these auxiliary decision variables are approximated by continuous boundedness constraints. Then, we approximate the control by a piecewise constant function, and apply a novel time-scaling transformation to map the retention times and control switching times to fixed points in a new time horizon. The retention times and control switching times become decision variables in the new time horizon. In addition, the max-min objective function is approximated by a minimization problem subject to an additional constraint. On this basis, the optimal control problem is reduced to an approximate nonlinear optimization problem subject to smooth constraints, which is then solved using a recently developed exact penalty function method. Numerical results obtained show that this approach is highly effective.Finally, some concluding remarks and suggestions for further study are made in the conclusion chapter.
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31

Warren, Joel Christian. "Structural Design Solver Development for Overhead Industrial Cranes: Equations-Of-State Solver Method". Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1328021324.

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32

Altrén, Jesper y Mattias Lyth. "Solvency II - A compliance burden or an opportunity for the Swedish non-life insurance industry?" Thesis, Linköping University, Department of Management and Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8339.

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Insurance companies and banks are of great importance to the economy, which is why their stability must be ensured. In order to prevent bankruptcies in the financial sector, these companies are subject to strict regulations, which set standards for risk management and the amount of reserve capital required. Such capital reserves act as safety buffers to protect the customers from extraordinary events. In the insurance industry, the reserve capital is referred to as the solvency margin.

Solvency II is new set of insurance regulations that aims to set a common standard regarding solvency capital and risk management for insurance companies within the European Union. The potential costs and benefits of the regulations are of importance not only to insurance companies but also to those firms that offer services and products to the insurance industry in the field of risk management. Solvency II is often compared to the Basel II accord for banks, which had a strong business case in the way that banks could significantly lower their reserve capital and use it for other purposes. The question is, however, whether insurance companies can expect similar benefits from Solvency II.

The purpose of this study is therefore to explain how the Solvency II regulations will affect risk management in the Swedish non-life insurance industry, and whether these changes can result in opportunities for insurance companies. This is achieved by studying the new regulations and conducting a number of interviews with insurance company representatives as well as industry experts. Four potential effects of Solvency II have been investigated: capital levels, insurance pricing, credit ratings and reinsurance.

The findings of the study indicate that no obvious benefits related to the potential effects above can be realised by complying with Solvency II. The future capital requirements will come close to those already enforced by supervisors today, resulting in a minor change that can go both ways. Neither credit ratings nor reinsurance covers seem to become notably affected by Solvency II. As for insurance pricing, an increasingly sophisticated risk-based allocation of the cost of solvency capital provides the most notable opportunity of Solvency II, but at present, no conclusions can be drawn regarding the effects of such changes. On the other hand, Solvency II will put pressure on improving systems to ensure the quality and traceability of data.

Thus, the actual changes in risk management practices are not expected to be substantial among Swedish non-life insurance companies, and it therefore seems unlikely that insurance companies would be willing to invest as heavily in reaching Solvency II compliance as banks have done in Basel II.

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33

Huss, Valérie. "Etude de la dégradation d'un solvant industriel : le mélange TBP - isopar". Aix-Marseille 3, 1991. http://www.theses.fr/1991AIX30064.

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La purification des solutions de nitrate d'uranyle est realisee par extraction liquide-liquide. Le solvant est le melange tbp/isopar. Les differentes mises en contact engendrent des produits de degradation du tbp et du melange tbp/diluant, composes a longue chaine caracterises par des proprietes tensio-actives importantes. Ces produits ne sont pas elimines lors des etapes de regeneration du solvant et s'accumulent dans le solvant. Ils provoquent d'une part des troubles au niveau de l'extraction et d'autre part des problemes de decantation de phases lors des etapes de regeneration du solvant par lavage avec des solutions basiques de na2co3. La recherche bibliographique nous a permis de mettre en evidence differents types de produits de degradation: les acides carboxyliques, les acides hydroxamiques, les composes nitros et les esters phosphoriques. Ces entites presentent la particularite de posseder des structures a longue chaine, ce qui leur confere d'importantes proprietes tensio-actives. Cette alteration varie suivant le type de concentre traite et la nature du diluant. Pour minimiser la degradation, il faudrait utiliser un solvant lineaire et exempt d'aromatiques. Ces especes peuvent etre eliminees par lavage du solvant avec une solution de soude ou de potasse ou par adsorption sur alumine ou magnesie. Mais cette technique n'est pas integrable aisement au sein d'un procede industriel
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34

Koukoulis, Constantinos G. "The application of knowledge based techniques to industrial maintenance problems". Thesis, Queen Mary, University of London, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327306.

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Montoya, Carmen Alicia Moreno. "Continuous catalyst free production of biodiesel from agro industrial waste with green solvents". Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/8057.

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Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica
The aim of this thesis consists in the study of the production of biodiesel via catalyst free direct transesterification of spent coffee ground oil with supercritical methanol in a continuous process. Supercritical methanol is passed through a packed bed reactor with the spent coffee grounds. Inside the reactor supercritical methanol extracts the triacylglycerols, which are immediately transesterified into fatty acid methyl esters. Therefore, the extraction and transesterification processes take in a single step. It was demonstrated that, at the optimal conditions of operation of 533 K, 10 MPa and solvent flow of 1 ml/min, the maximum yield for the total process was 83%. The effect of supercritical CO2 (ScCO2) as co-solvent was also studied. When using carbon dioxide as co-solvent at supercritical conditions, higher yields were obtained at milder temperature conditions. A maximum yield for the total process of 86% was obtained at 314 K for extraction of oil, 473 K for the reaction into FAME, 10MPa, solvent flow of 4.13 ml/min and a volume fraction of ScCO2 in the solvent feed of 27%.
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36

Baldisser, Gianluca <1995&gt. "Sintesi solvent-free di un additivo superfluidificante per calcestruzzo a base di policarbossilati eteri". Master's Degree Thesis, Università Ca' Foscari Venezia, 2019. http://hdl.handle.net/10579/15885.

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In questo lavoro di tesi si è cercato di ottimizzare la sintesi di un additivo superfluidificante a base di policarbossilati eteri impiegando come substrati acido acrilico e metil polietilenglicole (mPEG) a catena lunga. L’impiego di una catena mPEG più lunga, rispetto alle consuete sintesi industriali di questi additivi (BASF), comporta una maggiore difficoltà nell'eseguire l’esterificazione che consiste in un primo stadio di reazione tra il substrato acrilico e mPEG, in presenza di un inibitore di polimerizzazione e di un secondo stadio di polimerizzazione in soluzione acquosa in presenza di un iniziatore radicalico (IdR) e di un regolatore di catena (RdC). Infatti utilizzando catene di mPEG più lunghe, è necessario aumentare la temperatura di esterificazione che implica la necessità di introdurre ulteriore inibitore di polimerizzazione che inibisce di fatto la fase di polimerizzazione. Pertanto, in questo lavoro di tesi si è cercato di controllare la fase di esterificazione durante la fase di polimerizzazione, introducendo nel reattore contemporaneamente RdC, IdR, e il catalizzatore acido di esterificazione (CdE). Sono state investigate differenti concentrazioni di RdC, e di CdE, registrando una forte interazione reciproca imprevedibile. Di conseguenza, è risultato necessario variare la metodica introducendo RdC e CdE con tempistiche differenti. Sulla base di queste osservazioni preliminari è stata sviluppata una nuova metodologia di sintesi in 2 fasi: una prima di polimerizzazione e una seconda di esterificazione. L’obiettivo della polimerizzazione è quello di ottenere lo scheletro della molecola sul quale, successivamente, legare le molecole di mPEG durante l’esterificazione. La sperimentazione è stato sviluppata impiegando il “disegno sperimentale”, metodo che consente di ridurre considerevolmente i tempi e i costi della ricerca. I risultati ottenuti sono molto interessanti sia per quanto riguarda il profilo del polimero che le sue prestazioni. Infatti, la prova del flow, a pari prestazione, richiede il 33% in meno di dosaggio di additivo, con un evidente risparmio economico. Studi successivi dovranno necessariamente approfondire la sintesi della catena poliacrilica, poiché la viscosità del sistema (sintesi solvent-free) comporta notevoli limitazioni reattive. Sintetizzando una catena poliacrilica con un indice di polidispersione basso e un peso molecolare ottimale, sulla quale legare le catene di mPEG, si potrebbero conseguire ulteriori miglioramenti.
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37

Özçam, Burcu. "Genetic Algorithms for Solving Disjoint PathProblem with Proportional Path-Costs". NCSU, 2001. http://www.lib.ncsu.edu/theses/available/etd-20010629-132423.

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This study was conducted to develop solution algorithms for the edge-disjoint path problem with proportional path-costs in an undirected network with single source-destination pair. Edge-disjoint path problem arises in connectivity analysis, network flow problems, VLSI-design and variety of applications. The complexity of all the variants of the disjoint path problemsis NP-hard. We proposed two genetic algorithms which differ in solution representation.The performance of both algorithms tested on small, medium and large size complete graphs using different cost structures. As a result, genetic algorithm with priority-based encoding is shown to beinefficient, whereas genetic algorithm with variable-length path encoding is shown to be satisfactoryfor finding the edge-disjoint paths with proportional path-costs.

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38

Khadhraoui, Boutheina. "éco-extraction assistée par ultrasons des plantes médicinales : mécanisme(s), intensification et industrialisation ULTRASOUND TECHNOLOGY FOR FOOD PROCESSING, PRESERVATION AND EXTRACTION Histo-cytochemistry and scanning electron microscopy for studying spatial and temporal extraction of metabolites induced by ultrasound. Towards chain detexturation mechanism Microscopic imaging as a tool to target spatial and temporal extraction of bioactive compounds through ultrasound intensificationUltrason. Review of Alternative Solvents for Green Extraction of Food and Natural Green solvents for analytical chemistry". Thesis, Avignon, 2019. http://www.theses.fr/2019AVIG0715.

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Le retour à la naturalité a favorisé le développement des compléments alimentaires à base de ressources végétales qui apparaissent comme un réservoir quasi-infini de nutriments et de substances naturelles bioactives. Ceci fait de l’extraction solide/liquide une étape incontournable au sein des industries intéressées par ce type de molécules. Avec les préoccupations environnementale set sociétales, il est devenu nécessaire d’inventer et développer de nouveaux procédés qui répondent aux six principes de l’éco-extraction. Cette démarche a totalement inspiré cette thèse qui a pour principal objectif le développement d’une technique d’éco-extraction assistée par ultrasons en substitution de la technique conventionnelle. Ce travail a permis de montrer qu’il était possible d’intensifier l’extraction de composés d’intérêt en utilisant les ultrasons avec une meilleure sélectivité et de meilleurs rendements d’extraction. Une attention particulière a été accordée à la compréhension des mécanismes d’action des ultrasons via une étude macroscopique et microscopique approfondie des structures végétales. Cette investigation a prouvé que les ultrasons agissent différemment en fonction des structures végétales et de leurs propriétés morphologiques et chimiques qui leur confèrent un degré de résistance plus ou moins important face à l’action des ultrasons. Partant de ces résultats, l’étude macroscopique et microscopique a été définie comme un outil de décision pour une extraction ciblée. Cette variabilité a été aussi constatée à l’échelle industrielle prouvant davantage l’importance de l’analyse microscopique. Enfin, le procédé d’extraction par ultrasons a été adopté à l’échelle industrielle pour ses performances d’extraction et pour son empreinte environnementale significativement réduite par rapport au procédé CV. Ce travail a également conduit à des travaux complémentaires sur l’étude du potentiel de solubilisation des produits naturels en vue d’une utilisation pour l’extraction de composés végétaux difficiles à solubiliser dans l’eau. Des résultats prometteurs ont été obtenus en termes de pouvoirs de solubilisation et d’extraction notamment à partir de la matière végétale broyée. Les résultats de cette dernière partie soulèvent cependant des questions qui pourraient faire l’objet de futures recherches et de perspectives pour ce travail qui sont principalement liés à l’étude des problèmes liés au changement du solvant et au prétraitement de la matière première et de la faisabilité industrielle de ce nouveau procédé
With recent trends in the increasing interest to environmental, economic and safety considerations,extraction techniques have largely focused on finding solutions with sustainable and green values toimplement in food processing, cosmetic and pharmaceutical industries. In this context, new “green”extraction techniques were developed such as Ultrasound-Assisted Extraction (UAE). The mainobjective of this thesis is industrial implementation of this new process in substitution to theconventional (CV) process. It has been shown in this work that the extraction of compounds ofinterest from rosemary and other plant matrices could be intensified using ultrasound, and thatdifferent performance gain could be achieved according to the plant matrix structural properties.Indeed, macroscopic and microscopic investigation of untreated and treated raw materials provedthat US act through different mechanisms and its resulting impacts can be extremely limited by plantstructural morphological and chemical properties, especially those of the specialized structures.Significant variability in performance gain was also observed at the industrial scale. Overall, USappears as a promising technique with a significant performance gain in terms of extraction yield andselectivity. Moreover, this process presents low environmental footprint compared to the CV one.Finally, it has been shown that natural products, such as honey and fruit juices, can be used toimprove solubilization and extraction of molecules that are poorly soluble in water. Encouragingresults were obtained in terms of solubilization and extraction abilities, especially from ground rawmaterials. However, these results raise questions related to the feasibility of industrialimplementation of this new process
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39

Aguilera, Segura Sonia Milena <1990&gt. "Physical chemistry of the interactions between multicomponent solvents and biomass". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amsdottorato.unibo.it/9144/1/2019-Aguilera_Segura-UniBo.pdf.

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Extraction of cellulose and lignin from plant biomass remains a major issue for enabling more economic and green production of lignocellulosic renewable fuels and byproducts. Although the use of multicomponent solvents has provided remarkable results in wood fractionation processes most of the currently used methods rely on empirically elaborated protocols. Understanding the physicochemical mechanisms of biomass breakdown and its interactions with solvent medium during fractionation will lead to more efficient use of biomass. This defined the focus in this thesis work on a systematic and detailed description of the interactions between ligoncellulose components with binary water-organic mixtures of ethanol and acetonitrile. Our results and their analysis were obtained predominantly with molecular dynamics (MD) simulations, and supported by additional studies of quantum chemical (Density Functional Theory) and mixed quantum mechanical (QM) and classical MD scheme (QM/MM). With these tools we first established a non-linear behavior of the mixed solvent structures, thermodynamic properties and dynamic hardness, as a measure for their global reactivity. The analysis of the average numbers of HBs with the liquid composition shows that alcohol molecules tend to substitute water molecules, allowing compensating for the loss of H-bonds in the water solvent domains. The role of organic component in water solvent mixtures on the conformational changes induced in the main wood components (cellulose, lignin and hemicellulose) is highlighted and their dependence on distinct solvent compositions is unveiled for each organic solvent component and its content in water. This dependence is explained by preferential solute-solvent interatomic interactions as a function of solvent compositions. Subsequently, the evolution of interaction forces in lignin-cellulose and lignin-xylan complexes are also found to have solvent-dependent profiles. All this supports the general conclusion about specific solvent actions on lignocellulose compounds being the driving factors in the observed macroscopic non-linear behavior in wood swelling in mixed water-organics.
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40

MacPherson, Randall T. "The relationship among content knowledge, technical experience, cognitive styles, critical thinking skills, problem solving styles, and near transfer trouble shooting technological problem solving skills of maintenance technicians /". free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9841170.

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41

Bachir, Souley. "Oxydation hydrothermale en régime sous-critique de solvants et complexants potentiels du combustible nucléaire". Aix-Marseille 1, 1999. http://www.theses.fr/1999AIX11006.

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Ce memoire concerne la protection de l'environnement, plus particulierement la destruction de solvants et complexants organiques employes dans l'industrie nucleaire. L'utilisation du procede de l'oxydation hydrothermale parait bien adaptee en raison de son caractere confine, pour degrader la matiere organique et reduire le volume des dechets ultimes. Ce procede consiste a oxyder dans l'eau le carbone organique de maniere a le transformer en gaz carbonique. Il a ete decrit depuis les annees 1950, mais son application au traitement de dechets est tres limitee. Cependant, au cours de la presente decennie, les pressions fortes pour resoudre divers problemes lies aux dechets ont entraine un regain d'activite en recherche et developpement autour de ce procede. Notre travail aborde differents aspects du procede qui vont de l'optimisation des rendements de degradation en tenant compte des differents facteurs susceptibles influencer ces rendements, a la formation des sous-produits ainsi que la cinetique et la mecanisme de la reaction. Un autre aspect de ce travail porte la possibilite d'un couplage entre l'oxydation hydrothermale et la technique de biodegradation dans l'optique du traitement des boues des stations d'epuration. Il s'agit dans ce cas, de tester l'abattement de certains sous-produits formes lors de l'oxydation hydrothermale par une biodegradation par les bacteries. L'ensemble des resultats montre que les rendements de degradation sont tres variables en fonction des substrats et des conditions operatoires. La temperature de reaction et la pression partielle d'oxygene sont le principaux facteurs qui favorisent ces rendements. L'augmentation de la concentration en substrat contribue par contre a le diminuer. La destruction du cot se deroule exponentiellement en fonction du temps. Cette destruction evolue en deux etapes distinctes : une premiere rapide qui dure 20 minutes environs suivie d'une seconde etape beaucoup plus lente. La reaction est generalement partielle et aboutit a la formation sous-produits legers en solution. Cette reaction suit un mecanisme radicalaire. Les radicaux hydroxyl, hydroxycarbonyl et azote sont les principaux identifies. La biodegradation anaerobie par les methanosarcines permet une reduction sensible des teneurs en acetate et methanol dans les effluents mais le metabolisme mis en jeu n'est pas la methanisation compte tenu des conditions defavorables imposees a la microflore.
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42

Palmer, Jennifer Lynn. "Organizational Dynamics, Issue Importance, and Creativity in Problem-Solving". W&M ScholarWorks, 1997. https://scholarworks.wm.edu/etd/1539626147.

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43

Khaewsukkho, Smart. "A Genetic Algorithm Implementation of Design Skeletons for Solving the Facility Layout Problem". The Ohio State University, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=osu1396347382.

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Prieto, Luisa Perpetua Simenta Valente Estevez. "Studies of the interaction of selected organic solvents with human liver cytochrome P450". Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310861.

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45

Bousmar, Khadija. "Conception d'un solveur matériel spécifique pour la résolution rapide du problème SAT appliqué à l'évaluation du risque en génie industriel". Electronic Thesis or Diss., Université de Lorraine, 2018. http://www.theses.fr/2018LORR0341.

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Dans cette thèse, nous abordons un sujet dans le domaine du génie industriel se rapportant à la résolution d’un problème de décision, fondamental dans la théorie de la complexité et de la satisfiabilité propositionnelle, nommé SAT. Ce dernier est présenté généralement sous un formalisme mathématique, permettant de modéliser des problèmes complexes, tant académiques qu’issus du monde réel. Ces problèmes sont présentés sous une forme booléenne dans le but de tester leur faisabilité. Ils sont relatifs à plusieurs domaines applicatifs, tels que la vérification de matériels et logiciels, les télécommunications, la médecine, et notamment la planification. L’évolution et les progrès observés ces dernières années dans le domaine de la résolution des problèmes utilisant SAT, a permis de renforcer la conviction que ce domaine peut être encore plus prometteur dans la résolution des problèmes difficiles (complexes ou NP complexes) et qu’il faut lui accorder plus d’intérêt. C’est dans cette optique, que nous nous sommes intéressés à l’appliquer sur des problèmes purement industriels afin de proposer des contributions dans un nouveau domaine d’application. L’objectif de cette thèse est de développer des outils d’aide à la décision pouvant être employés dans le domaine de la gestion du risque industriel. Bien que le formalisme SAT soit très puissant, dans la pratique, quand les problèmes ciblés sont de taille importante, les outils de résolution s’avèrent moins performants. Par conséquent le but de ces travaux de recherche est de développer une architecture matérielle rapide (avec une implémentation ciblée sur FPGA) permettant une accélération massive de la résolution grâce au niveau élevé de traitement parallèle de l’approche matérielle. Dans cette thèse, deux aspects principaux sont étudiés et développés pour résoudre un problème de gestion des ressources de production industriel. Ces aspects sont d’une part, les principes de base de fonctionnement et de résolution d’un solveur générique paramétrable SAT, d’autre part, des méthodes adaptées au principe de fonctionnement retenu pour le solveur matériel. En effet, bien que ciblant des buts comparables à ceux de l’approche logicielle (optimisation du parcours de l’espace de recherche), l’approche matérielle requiert le développement de méthodes de résolutions spécifiques. Ces dernières ont été spécifiquement optimisées pour le domaine applicatif cible qui est celui de l’industrie. L’efficacité de l’approche matérielle développée a montré des résultats satisfaisant, point de vu du nombre de variables utilisés et temps de résolution sur les problèmes testés
In this thesis, we address a topic in the field of industrial engineering related to solving a fundamental decision problem in the theory of complexity and propositional satisfiability called SAT. The latter is usually presented in a mathematical formalism, allowing the modelling of complex problems, both academic and from real world. These problems are presented in boolean form in order to check their feasibility. They relate to several application areas, such as hardware and software verification, telecommunications, medicine, and planning. The evolution and progress observed in recent years in the field of problem-solving using SAT has made it possible to reinforce the conviction that this field can be even more promising in solving difficult (complex or complex NP) problems and that more attention needs to be dedicated to it. It is with this in mind that we have taken an interest in applying it to purely industrial problems in order to propose contributions in a new field of application. The objective of this thesis is to develop decision-support tools that can be used in the field of industrial risk management. Although the SAT formalism is very powerful, in practice, when the targeted problems are large, the resolution tools prove to be less effective. Therefore, the aim of this research is to develop a rapid hardware architecture (with FPGA-targeted implementation) that allows massive acceleration of resolution due to the high level of parallel processing of the hardware approach. In this thesis, two main aspects are studied and developed to solve a problem of management of industrial production resources. These aspects are, on the one hand, the basic principles of operation and resolution of a generic SAT configurable solver and, on the other hand, methods adapted to the operating principle adopted for the hardware solver. Indeed, although targeting goals comparable to those of the software approach (optimization of the search space path), the material approach requires the development of specific resolution methods. These have been specifically optimised for the target application area of industry. The effectiveness of the material approach developed showed satisfactory results, point of view of the number of variables used and resolution time on the problems tested
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46

Evans, Marise Meredith Tillman Thomas S. "Maximizing collaborative problem solving within higher education design studios with a minimal open floor plan". Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SUMMER/Industrial_Design/Thesis/Evans_Marise_58.pdf.

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VerGow, Zachary J. "Modeling and solving coupled decision problems in design for recycling". Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/17322.

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48

Bercsey, Tibor y Klaudia Nagy. "Applying inventive problem solving methods at the early stage of industrial product design". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-232922.

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The paper introduces a methodological overview followed by thoughts of the recent problems of using these theories at the industrial ground offering some solutions for improvement. Shows a case study where several semesters of the Integrated Product Design courses were observed at the Department of Machine and Product Design at the Budapest University of Technology and Economics (BME). The aim of the presented study has been to evaluate a selected product design project from the aspect of the effectiveness of the previous methodological training. Based on these findings we provide some suggestions for the design education to support the early stage of the design process. [...from the introduction]
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49

Bercsey, Tibor y Klaudia Nagy. "Applying inventive problem solving methods at the early stage of industrial product design". TUDpress - Verlag der Wissenschaften GmbH, 2012. https://tud.qucosa.de/id/qucosa%3A30783.

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The paper introduces a methodological overview followed by thoughts of the recent problems of using these theories at the industrial ground offering some solutions for improvement. Shows a case study where several semesters of the Integrated Product Design courses were observed at the Department of Machine and Product Design at the Budapest University of Technology and Economics (BME). The aim of the presented study has been to evaluate a selected product design project from the aspect of the effectiveness of the previous methodological training. Based on these findings we provide some suggestions for the design education to support the early stage of the design process. [...from the introduction]
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50

Burgués, Ceballos Ignasi. "Towards industrial viability of organic solar cells: ITO-free, green solvents and technological aspects for upscalability". Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/283360.

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Des de la seva aparició com a alternativa per la conversió d’energia fotovoltaica, el camp de les cel·les solars orgàniques ha experimentat un progrés significatiu, especialment en els darrers 15 anys. El gran interès en la tecnologia fotovoltaica orgànica (OPV, per les sigles en anglès) es deu principalment al seu potencial baix cost. Rellevants avenços científics han empès les eficiències de conversió energètica fins al 12%, fet que encoratja a acostar les OPV al mercat. Tanmateix, altres aspectes decisius per la seva industrialització han estat menys atesos. Aquesta tesi tracta tres qüestions clau que la tecnologia OPV ha d’afrontar per tal d’assolir una transferència fiable del laboratori a la industria. En primer lloc, es necessiten estratègies pel processat i post-processat a gran escala, idealment amb un cost reduït. En aquest treball es presenta una amplia investigació en inkjet printing. És necessari tenir un profund coneixement d’aquesta tècnica compatible amb roll-to-roll per tal d’assolir morfologies de capa adequades. S’ha trobat que la cinètica d’assecat de les capes és especialment crítica. En relació a això, s’ha desenvolupat un nou mètode per determinar patrons d’impressió apropiats per la deposició de la capa activa. A més, s’ha demostrat l’ús d’un tractament alternatiu anomenat vapour printing en dispositius OPV. Utilitzant aquest mètode amb vapor de dissolvent adequat, el tractament de la capa activa es pot assolir en temps molt més curts en comparació a altres tècniques. Un altre aspecte que ha estat poc atès està relacionat amb els dissolvents utilitzats pel processat dels OPV, especialment per la deposició de la capa activa. Típicament s’utilitzen dissolvents halogenats, com el clorbenzè o el diclorbenzè, essent alguns d’ells prohibits per aplicacions industrials. Substituir-los per formulacions verdes és, per tant, una necessitat primordial. Per tal de trobar sistemes aptes de dissolvents verds, s’ha utilitzat un mètode basat en la solubilitat. Aquest mètode, prèviament demostrat per cel·les solars polimèriques, s’estén de manera satisfactòria en aquesta tesi en dispositius basats en petita molècula. També s’aporten nous coneixements sobre la precisió del mètode. L’oxid d’indi i estany (ITO, per les seves sigles en anglès), freqüentment utilitzat com a elèctrode conductor transparent, contribueix de manera important en el cost d’un mòdul OPV. Altres raons per reemplaçar aquest component inclouen la seva modesta flexibilitat i conductivitat, el que pot limitar l’extracció de corrent elèctric en dispositius de gran àrea. Una possible alternativa són les xarxes metàl·liques combinades amb una capa transparent semiconductora. Tot i resoldre l’aspecte de la conductivitat, altres factors limiten encara l’extracció de corrent. El nou mètode utilitzat en aquest treball per preparar aquestes estructures venç aquests factors. Es demostren dispositius eficients lliures de ITO.
Desde su aparición como alternativa para la conversión de energía fotovoltaica, el campo de las células solares orgánicas ha experimentado un progreso significativo, especialmente en los últimos 15 años. El gran interés en la tecnología fotovoltaica orgánica (OPV, por sus siglas en inglés) se debe principalmente a su potencial bajo coste. Relevantes avances científicos han empujado las eficiencias de conversión energética hasta el 12%, lo que alienta el acercamiento de las OPV al mercado. Sin embargo, otros aspectos decisivos para su industrialización han sido menos atendidos. Esta tesis trata tres cuestiones clave que la tecnología OPV tiene que afrontar para alcanzar una transferencia fiable del laboratorio a la industria. En primer lugar, se necesitan estrategias para el procesado y post-procesado a gran escala, idealmente con un coste reducido. En este trabajo se presenta una amplia investigación en inkjet printing. Es necesario tener un profundo conocimiento sobre esta técnica compatible con roll-to-roll para obtener morfologías de capa adecuadas. Se ha encontrado que la cinética de secado de la capa es especialmente crítica. En relación a esto, se ha desarrollado un nuevo método para determinar patrones de impresión adecuados para la deposición de la capa activa. Además, se ha demostrado el uso de un tratamiento alternativo llamado vapour printing en dispositivos OPV. Utilizando este método con vapores de disolvente aptos, el tratamiento de la capa activa se puede alcanzar en tiempos mucho más cortos en comparación con otras técnicas. Otro aspecto que ha sido poco atendido está relacionado con los disolventes utilizados en el procesado de las OPV, especialmente en la deposición de la capa activa. Típicamente se emplean disolventes halogenados, como el clorobenceno o diclorobenzeno, estando alguno de ellos prohibidos en aplicaciones industriales. Su substitución por formulaciones verdes es, por tanto, una necesidad primordial. Para encontrar sistemas aptos de disolventes verdes, se ha utilizado un método basado en la solubilidad. Este método, previamente demostrado para células solares poliméricas, se extiende de manera exitosa en esta tesis para dispositivos basados en pequeña molécula. También se aportan nuevos conocimientos sobre la precisión del método. El óxido de indio y estaño (ITO, por sus siglas en inglés), frecuentemente utilizado como electrodo conductor transparente, contribuye de manera importante en el coste de un módulo OPV. Otros motivos para substituir este componente incluyen su modesta flexibilidad y conductividad, lo que puede limitar la extracción de corriente eléctrica en dispositivos de gran área. Una posible alternativa son las redes metálicas combinadas con una capa transparente semiconductora. A pesar de que el aspecto de la conductividad queda solucionado, otros factores limitan aún la extracción de corriente. El nuevo método utilizado en este trabajo para preparar estas estructuras vence estos aspectos. Se demuestran dispositivos eficientes libres de ITO.
Since its emergence as an alternative for photovoltaic energy conversion, the field of organic solar cells has experienced significant progress, especially in the last 15 years. The high interest in organic photovoltaics (OPV) technology is mostly due to its lowcost potential. Relevant scientific advances have pushed power conversion efficiencies up to 12%, which is encouraging for bringing OPV to market. However, other decisive aspects for their industrialisation have been less attended. This thesis deals with three key issues that OPV technology has to face in order to achieve a reliable lab-to-fab transfer. First, approaches for large-scale processing and post-processing are needed, ideally with reduced cost. In this work a broad investigation in inkjet printing is presented. A deep understanding on this roll-to-roll compatible technique is necessary to achieve suitable layer morphology. The drying kinetics of the wet film has been found to be especially critical. In relation to this, a new method to determine appropriate printing patterns for active layer deposition has been developed. Moreover, an alternative post-processing treatment called vapour printing is demonstrated for OPV devices. Using this method with suitable solvent vapour, the annealing of the active layer can be achieved in much shorter times as compared to other treatments. Another aspect that has been poorly attended is related to the solvents used for OPV processing, specifically for active layer deposition. Typically halogenated solvents such as chlorobenzene or o-dichlorobenzene are employed, being some of them banned for industrial applications. Their replacement by green formulations is therefore a major need. In order to find suitable green solvent systems, a method based on solubility has been used. This method, previously demonstrated for polymeric solar cells, is successfully extended in this thesis for small molecule based devices. New insights into the accuracy of the method are also provided. A major contributor to the cost of an OPV module is the indium-tin-oxide (ITO), commonly used as a transparent conductive electrode. Further reasons to replace this component include its modest flexibility and conductivity, which may limit current extraction in large area devices. One possible alternative are metallic grids combined with a transparent semiconductor layer. Although the conductivity issue is solved, other factors still limit current extraction. The new method used in this work to prepare such structures overcomes these features. Efficient, ITO-free devices are demonstrated.
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