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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

BIOLOGICAL DESIGN OF CONTINUOUS MICROALGAE SYSTEMS: A REVIEW

Drabold, Edward T. 20 May 2021 (has links)
No description available.
2

Synthèse de nouveaux nanophotocatalyseurs en microfluidique supercritique / Synthesis of Novel Nanophotocatalyst in Micro/Millifludic Supercritical Reactor

Ravi Anusuyadevi, Prasaanth 12 December 2018 (has links)
Ce sujet de thèse fait partie d’un projet européen visant à développer l’utilisation de la lumière solaire pour créer des produits à haute valeur ajoutée en utilisant la photochimie catalytique. Dans ce contexte, la synthèse de nanophotocatalyseurs est essentielle car les caractéristiques des nanomatériaux doit être maîtrisées pour optimiser l'efficacité de la réaction. Les méthodes de synthèses utilisant les fluides supercritiques (haute pression / haute température) se sont révélés être des procédés de choix pour de tels développements. Combinés à l’utilisation de microréacteurs, il est alors possible d’accéder à un contrôle fin des propriétés du matériau, notamment celles de surface. Les objectifs de ce projet sont de (i) développer des procédés de synthèse permettant de concevoir de nouveaux nanophotocatalyseurs basés sur l’oxyde de titane et des nanoparticules de semi-conducteurs de nitrures, en particulier GaN/TiO2 et GaxIn1-xN/TiO2, (ii) de tester l’efficacité photocatalytique de ces matériaux sur plusieurs réactions photochimiques modèles (oxydation des thiols, trifluorométhylation, conversion des amines en imines), à la fois en réacteur fermé et en réacteurs photochimiques sous flux et (iii) d’étudier les options de changement d’échelle pour améliorer les taux de production de ces nanophotocatalyseurs. / This PhD thesis is part of a larger European ITN project (Photo4Future) dealing with improvement of the use of sun light for making valuable products through new heterogeneous catalytic photochemical processes. In this context, the synthesis of nanophotocatalysts is essential since their characteristics must be controlled to optimize the process efficiency towards the desired products. Supercritical fluids synthesis approaches (high pressure / high temperature) have proven to be promising for such developments. Combined to microreactors, it is then possible to reach a precise control of material properties, including surfaces. The objectives of this project are (i) to develop synthetic methods for designing new nanophotocatalysts based on titania and nitrides quantum dots, in particular GaN/TiO2 and GaxIn1-xN/TiO2, (ii) to test their photocatalytics efficiency on several model photochemical reactions (oxidation of thiols, trifluoromethylation and amine to imine conversion), both in batch mode and using continuous flow photochemical reactors and (iii) to investigate the scale-up options for increasing the production rates of such nanophotocatalysts.
3

Criação de fluxo de produção enxuta em empresas com características de processo contínuo / Criation of lean production flow in companies with continuous process characteristics

Moraes, Aroldo Jose Isaias de 30 September 2005 (has links)
Este trabalho mostra uma aplicação de conceitos de produção enxuta em uma empresa de processo contínuo. Existe uma percepção por parte de algumas destas empresas de que, sendo de fluxo contínuo, elas se adequam mais aos princípios da produção em massa, não sendo portanto aplicáveis a elas os conceitos de produção enxuta. Também existe a crença, igualmente questionável, de que elas já são enxutas por natureza, devido ao elevado nível de automação com pouca manipulação e movimentações discretas. Este trabalho mostra que isso nem sempre é verdade e que uma empresa de processo contínuo pode se beneficiar consideravelmente da aplicação de conceitos de manufatura enxuta. É apresentada aqui uma revisão bibliográfica das principais ferramentas e conceitos de produção enxuta. Também é apresentado um caso já documentado na literatura técnica de aplicação destes conceitos em uma empresa química de processo contínuo. A seguir é mostrado o caso de aplicação de produção enxuta conduzida pelo autor em uma empresa de grande porte do setor termoplástico no estado de São Paulo, que tem características de processo contínuo. São também apresentados os resultados desta aplicação, evidenciando os ganhos obtidos como redução de 21% no indicador de refugo e 14% no tempo médio de set up, e algumas considerações sobre aplicação de produção enxuta em empresas desta natureza. / This paper shows a application of the concepts of lean production in a continuous process company. There is a misconception from some companies\' part that because they have continuous process, they fit more the mass production principles, therefore it is not valid to them the concept of lean production. There is also the belief, questionable as well, that they are naturally lean, due to the high level of automation with little handling and discret movements. This paper shows that this is not true and that continuous process company can benefit considerably from the application of the lean production concepts. It is presented here a bibliography review of the main tools and concepts of lean production. It is also presented a documented case of the application of these concepts in a chemical industry with continuous process. Next, the case of the application of lean production is showed, conducted by the author in a big company of termoplastic in the state of São Paulo that presents the characteristics of continuous process. The results of this application is presented, enfasizing the results obtained, it was obtained 21% of reduction in the screp indicator and 14% in the midium time of the set up and also some comments about the application of the lean production in these kinds of companies.
4

Effect of fruit flavor compounds on biogas production

Pandiyan, Ishwarya, Gudipudi, Sailaja January 2014 (has links)
The purpose of the experiment was to investigate the effect of fruit flavor compounds on biogas production from fruit wastes. The flavor compounds from different fruits were selected and synthetic medium was used throughout the experiment. The experiment was carried out both in batch and continuous process using thermophilic inoculums obtained from Söbacken waste management plant. The inhibitors were added at three different concentrations 0.05g/L, 0.5g/L and 5g/L respectively and were carried out in triplicates for batch cultivation.The result from batch cultivation showed that hexanal, (E)-2-hexanal, myrcene and octanol showed inhibitory activity. Hexanal, (E)-2-hexanal, myrcene, and octanol decreased biogas production by factor of 316.8%, 434.22%, 329.68% and 433.61% at concentration of 5g/L. Continuous experiment was carried out on Automatic Methane Potential Test System AMPTS II. Eight reactors, each with inhibitor compounds were used with a retention time of 30 days and an organic loading rate of 3g VS/day. The inhibitor concentration was increased from 0.5g/L to 5g/L and for some compounds up to 10g/L. During cultivation, several factors were measured periodically such as pH, total biogas production, biogas composition, FOS/TAC and VFA.The inhibitory effect was clearly shown at concentration higher than 0.5g/L. Addition of 5g/L hexanal, nonanal, (E)-2-hexanal, α-pinene , car-3-ene, myrcene and octanol resulted in reduction of biogas production by 81.2%, 4.67%, 50.74%, 7.06%, 24.01%, 31.84% and 52.85% respectively. When compared to batch process, continuous process required higher concentration of flavor compounds to reduce biogas production. This might be due to adaptation of cells towards toxic compounds during continuous process. / Program: Master of Science with a major in Resource Recovery-Industrial Biotechnology
5

Produção enzimática de biodiesel a partir de óleos láuricos em reatores de leito fixo duplo estágio incorporando coluna extratora do glicerol formado como subproduto / Enzymatic biodiesel production from lauric oils in a two-stage packed-bed reactors incorporating extraction column to remove glycerol formed as by-product

William Costa e Silva 09 August 2013 (has links)
O objetivo deste trabalho foi desenvolver um processo efetivo de síntese enzimática de biodiesel em reator de leito fixo, conectados em série, a partir de óleos vegetais operando em modo contínuo. Para o desenvolvimento do projeto, foram selecionados óleos vegetais de baixo impacto na cadeia alimentícia, tais como óleos de babaçu, macaúba e coco que apresentam composição predominantemente láurica (35-47%). A enzima selecionada para condução dos experimentos foi a lipase microbiana de Burkholderia cepacia imobilizada covalentemente em matriz híbrida sílica-PVA com comprovada eficiência na síntese de biodiesel a partir de diferentes matérias-primas lipídicas. Todos os experimentos foram efetuados na ausência de solventes a 50?C utilizando etanol como doador do grupo acila. Foram testados reatores de leito fixo (um estágio) e em série (dois estágios). A etapa inicial do trabalho consistiu em testes de desempenho do reator (um estágio) verificando a influência das propriedades dos óleos vegetais no rendimento do processo e atividade do biocatalisador. Apesar do biocatalisador ter apresentado elevado tempo de meia- vida > 373 h, nas condições testadas, independente do óleo usado a concentração máxima de ésteres esperada não foi alcançada (68,2%) limitando os rendimentos para valores máximos de 87,5%. Para contornar as restrições identificadas foi adotada uma configuração de reator de leito fixo dois estágios incorporando uma coluna recheada com resina catiônica (Lewatit GF 202) para adsorção do glicerol formado como subproduto. O desempenho do reator foi avaliado para substratos constituídos de óleos láuricos na razão molar óleo: etanol de 1:12, definindo os limites de operação em termos de vazão do substrato. Foi quantificado o desempenho do sistema para 4 diferentes vazões volumétricas correspondendo a tempos espaciais entre 7 a 17h e determinadas para cada condição a influência do tempo espacial na concentração de ésteres de etila formados, rendimentos de transesterificação e produtividade. O funcionamento do sistema foi comprovado quantitativamente para tempos espaciais no reator de 14h, fornecendo rendimentos de transesterificação médios de 95,9 ± 4,1% e valores médios de produtividade de 41,5 ± 1,5 mg.g-1.h-1. As amostras de biodiesel purificadas apresentaram viscosidade cinemática média de 5,5 ± 0,3 mm2.s-1, valor que atende a norma americana ASTM (D6751) e a brasileira pela resolução ANP n°14/2012. A lipase imobilizada em SiO2-PVA foi estável quanto à suas características morfológicas e catalíticas revelando tempo médio de meia-vida (t1/2) superior a 500 h. O emprego da configuração de reatores de leito fixo (PBR) em duplo estágio pode elevar os níveis de rendimento de transesterificação, aumentar a produtividade de biodiesel, por consequência reduzir o custo global do processo. As características globais do desempenho do sistema contínuo proposto torna atrativa a continuidade dos estudos em escala ampliada de processo. / The aim of this study was to develop an effective enzymatic continuous process to obtain biodiesel from vegetable oils in two-stage packed bed reactors. For this, non- edible vegetable oils (babassu, macaw palm and coconut) having predominant lauric acid (35-47%) composition were assessed. The selected enzyme was the microbial lipase from Burkholderia cepacia covalent immobilized on hybrid matrix silica-PVA (SiO2-PVA) which showed already satisfactory performance in the biodiesel synthesis from different lipid feedstocks. All experiments were carried out in solvent free system at 50°C using ethanol as acyl acceptor. Packed bed reactors (simple and two-stages) were tested. Preliminary work was focused on the determination of the influence of the properties of the vegetable oils on the process yield and biocatalyst activity using simple packed bed reactor. Under the conditions used, the biocatalyst was found to have high half-life time > 373 h and independent of the used oil the maximum concentration expected esters was not reached (68.2%) limiting the maximum yield to 87.5%. To overcome such constraints a two-stage packed bed reactor incorporating a column with cationic resins (Lewatit GF 202) to remove the glycerol formed as by-product was proposed. The reactor performance was evaluated for substrates consisting of lauric oils at molar ratio of oil-to-ethanol of 1:12, determining its operation limits in terms of substrate flow rate. The system performance was quantified for four different flow rates corresponded to spatial times from 7 to 17 h. For each condition, the influence of spatial times in the ethyl esters formation, transesterification yields and productivities were determined. The reactor operation was demonstrated for spatial time of 14 h, attaining transesterification yields of 95.9 ? 4.1% and productivities of 41.5 ? 1.5 mg.g-1.h-1.The immobilized lipase on SiO2-PVA was found to be stable regarding its morphological and catalytic characteristics, showing half-life time (t1/2) higher than 500 h. Biodiesel purified samples showed average kinematic viscosity of 5.5 ± 0.3 mm2.s-1, value that meets the criteria established by the American National Standard ASTM (D6751) and Brazilian ANP resolution No. 14/2012. Therefore, the continuous packed-bed reactor connected in series and glycerol separation system has a great potential for achieving high level of transesterification yields, raising biodiesel productivity, consequently decreasing industrial process cost. The performance characteristics of the proposed continuous system made attractive to develop further studies aiming at scaling up the process.
6

Selection and Use of Pantoea dispersa strain JFS as a Non-Pathogenic Surrogate for Salmonella Typhimurium Phage Type 42 in Flour

Fudge, James R. 01 August 2015 (has links)
Salmonella, a common food pathogen, costs more than any other pathogen in the United States in terms of health care costs and loss of work due to the illnesses it causes. Low-moisture foods, especially flour, are susceptible to being contaminated by Salmonella. Food producers want flour to be pathogen-free but to also retain the same functionality of non-treated flour. Heat treatment is the most common method employed for lowering the concentration of pathogens in food. However, heating can result in the loss of the flour’s functionality. Pantoea dispersa strain JFS has been isolated from flour as a nonpathogenic bacterial surrogate that closely matches the D-value of Salmonella in flour. Flour samples were subjected to dry heat (70, 75, and 80°C) and heat tolerance was determined by plating out at least four different time points for each temperature. The death rate of P. dispersa strain JFS was similar to (p<0.05) Salmonella. This strain of P. dispersa was then used as a surrogate for Salmonella in a continuous and batch heat treatment processes to determine the amount of kill achieved by each. The continuous process was conducted using varying levels of four independent variables: temperature, residence time, use of steam, and manipulation of initial water content. All 15 runs resulted in a reduction of at least 1.5 logs of the surrogate, with the greatest reduction being 2.5 logs. The batch process was conducted using one independent variable, temperature. All runs for the batch process resulted in a reduction of at least 2.5 logs of the surrogate, with the greatest reduction being 4.3 logs at 170°F. Both processes could be used to reduce any Salmonella present in flour.
7

An empirical investigation of the successful implementation of quality management in service organisations

Mahmood, Zahid, University of Western Sydney, Hawkesbury, Faculty of Management January 2000 (has links)
Quality management (QM) is a holistic management philosophy that emphasises the involvement of every employee at different levels of an organization to achieve customer satisfaction and improve organizational effectiveness through continuous process improvement. There has been a rising interest among service sector professionals in examining the applicability and usefulness of quality management methods in service organisations. Many service organisations that have implemented quality management has achieved substantial benefits, but it is clear that implementation initiatives in some organisations have failed to live up to expectations. These mixed results point to a need to identify the factors that lie behind the success and failures of quality management programs. Empirical research in this area is extremely limited. The results of the study point to the importance of the role of employee support and encouragement of departmental co-operation for the successful implementation of quality management programs. These factors were found to be important not only initially, but also throughout the whole implementation period of QM programs. Another interesting finding is the relationship between QM success and implementation issues concerning internal organisational communication, corporate cultural change, and internal marketing. Significant differences exist in the way that each of these factors are practised and emphasised across organisations. Respondents rated the way in which they drew upon the culture, communication pattern and other behaviour to promote QM within the organisation. They also rated how important they thought these various activities were. It was found when these factors were emphasised in QM programs the chance of successful implementation was increased. Implications for quality management professionals and suggestions for further research are discussed / Doctor of Philosophy (PhD)
8

Um estudo sobre o processo de trabalho na indústria automática de vidro /

Souza, Henrique Pavan Beiro de. January 2011 (has links)
Orientador: Adilson Marques Gennari / Banca: Felipe Luiz Gomes e Silva / Banca: José Walter Canoas / Resumo: A organização do trabalho na indústria automática de vidro é diretamente influenciada pela tecnologia inserida no processo produtivo. Neste ramo, uma cadeia integrada de autômatas realiza as operações físico-químicas que dão corpo ao produto final. Assim, o trabalhador não se envolve diretamente na fabricação e/ou montagem, ficando apenas como supervisor do processo. Isto implica uma série de características importantes à indústria automática vidreira: não só o processo de trabalho em si é marcado por tal nuance tecnológica como também - e conjuntamente com aquele - os processos de gestão e organização da empresa como um todo. Ao tratar da relação entre tecnologia e processo produtivo, não podemos deixar de analisar a própria relação capital/trabalho em sua dinâmica histórica. Por isso, o presente estudo se volta para uma análise crítica, com viés marxista, das principais formas de gerência do trabalho surgidas ao longo da história do capitalismo. Primeiramente, destacamos as vicissitudes da divisão do trabalho na manufatura, considerando o processo de subsunção formal à subsunção real do trabalho ao capital, ou seja, estudamos como ocorre a inserção da maquinaria no processo produtivo. Em seguida, analisamos o taylorismo e o fordismo - bem como o conceito de racionalização - como mecanismos de controle do trabalho operário. Por fim, investigamos a indústria de processo contínuo - ramo no qual se insere a indústria automática de vidro -, contrapondo-a com as características das indústrias tayloristas e fordistas / Abstract: The organization of work in the auto glass industry is directly influenced by technology inserted in the production process. In this business, an integrated chain of automata performs the physical-chemical operations that embody the final product. Thus, the worker does not get directly involved in manufacturing and/or assembly, being only a supervisor of the process. This implies a number of important features to the auto glass industry: not only the work process itself is marked by such technological nuance but also - and along with that - the processes of management and organization of the company as a whole. In addressing the relationship between technology and production process, we must search capital / labor relation in its historical dynamic. Therefore, this study turns to a critical analysis, biased Marxist, of the main ways of management work that emerged throughout the historyof capitalism. First, we highlight the vicissitudes of division of labor in manufacturing, considering the process of formal subsumption to real subsumption of labor to capital, ie, we study how the inclusion of machinery occurs in the production process. We then analyze Taylorism and Fordism - as well as the concept of rationalization - as mechanisms of control of labor worker. Finally, we investigate the continuous process industry - in which sector the auto glass industry is inserted - contrasting it with the characteristics of Taylorist and Fordist industries / Mestre
9

Um estudo sobre o processo de trabalho na indústria automática de vidro

Souza, Henrique Pavan Beiro de [UNESP] 02 September 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:24:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-09-02Bitstream added on 2014-06-13T20:12:23Z : No. of bitstreams: 1 souza_hpb_me_arafcl.pdf: 1077752 bytes, checksum: c974ff2d0de227542f988e8097aa9a5e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A organização do trabalho na indústria automática de vidro é diretamente influenciada pela tecnologia inserida no processo produtivo. Neste ramo, uma cadeia integrada de autômatas realiza as operações físico-químicas que dão corpo ao produto final. Assim, o trabalhador não se envolve diretamente na fabricação e/ou montagem, ficando apenas como supervisor do processo. Isto implica uma série de características importantes à indústria automática vidreira: não só o processo de trabalho em si é marcado por tal nuance tecnológica como também – e conjuntamente com aquele – os processos de gestão e organização da empresa como um todo. Ao tratar da relação entre tecnologia e processo produtivo, não podemos deixar de analisar a própria relação capital/trabalho em sua dinâmica histórica. Por isso, o presente estudo se volta para uma análise crítica, com viés marxista, das principais formas de gerência do trabalho surgidas ao longo da história do capitalismo. Primeiramente, destacamos as vicissitudes da divisão do trabalho na manufatura, considerando o processo de subsunção formal à subsunção real do trabalho ao capital, ou seja, estudamos como ocorre a inserção da maquinaria no processo produtivo. Em seguida, analisamos o taylorismo e o fordismo - bem como o conceito de racionalização - como mecanismos de controle do trabalho operário. Por fim, investigamos a indústria de processo contínuo – ramo no qual se insere a indústria automática de vidro -, contrapondo-a com as características das indústrias tayloristas e fordistas / The organization of work in the auto glass industry is directly influenced by technology inserted in the production process. In this business, an integrated chain of automata performs the physical-chemical operations that embody the final product. Thus, the worker does not get directly involved in manufacturing and/or assembly, being only a supervisor of the process. This implies a number of important features to the auto glass industry: not only the work process itself is marked by such technological nuance but also - and along with that - the processes of management and organization of the company as a whole. In addressing the relationship between technology and production process, we must search capital / labor relation in its historical dynamic. Therefore, this study turns to a critical analysis, biased Marxist, of the main ways of management work that emerged throughout the historyof capitalism. First, we highlight the vicissitudes of division of labor in manufacturing, considering the process of formal subsumption to real subsumption of labor to capital, ie, we study how the inclusion of machinery occurs in the production process. We then analyze Taylorism and Fordism - as well as the concept of rationalization - as mechanisms of control of labor worker. Finally, we investigate the continuous process industry - in which sector the auto glass industry is inserted - contrasting it with the characteristics of Taylorist and Fordist industries
10

Criação de fluxo de produção enxuta em empresas com características de processo contínuo / Criation of lean production flow in companies with continuous process characteristics

Aroldo Jose Isaias de Moraes 30 September 2005 (has links)
Este trabalho mostra uma aplicação de conceitos de produção enxuta em uma empresa de processo contínuo. Existe uma percepção por parte de algumas destas empresas de que, sendo de fluxo contínuo, elas se adequam mais aos princípios da produção em massa, não sendo portanto aplicáveis a elas os conceitos de produção enxuta. Também existe a crença, igualmente questionável, de que elas já são enxutas por natureza, devido ao elevado nível de automação com pouca manipulação e movimentações discretas. Este trabalho mostra que isso nem sempre é verdade e que uma empresa de processo contínuo pode se beneficiar consideravelmente da aplicação de conceitos de manufatura enxuta. É apresentada aqui uma revisão bibliográfica das principais ferramentas e conceitos de produção enxuta. Também é apresentado um caso já documentado na literatura técnica de aplicação destes conceitos em uma empresa química de processo contínuo. A seguir é mostrado o caso de aplicação de produção enxuta conduzida pelo autor em uma empresa de grande porte do setor termoplástico no estado de São Paulo, que tem características de processo contínuo. São também apresentados os resultados desta aplicação, evidenciando os ganhos obtidos como redução de 21% no indicador de refugo e 14% no tempo médio de set up, e algumas considerações sobre aplicação de produção enxuta em empresas desta natureza. / This paper shows a application of the concepts of lean production in a continuous process company. There is a misconception from some companies\' part that because they have continuous process, they fit more the mass production principles, therefore it is not valid to them the concept of lean production. There is also the belief, questionable as well, that they are naturally lean, due to the high level of automation with little handling and discret movements. This paper shows that this is not true and that continuous process company can benefit considerably from the application of the lean production concepts. It is presented here a bibliography review of the main tools and concepts of lean production. It is also presented a documented case of the application of these concepts in a chemical industry with continuous process. Next, the case of the application of lean production is showed, conducted by the author in a big company of termoplastic in the state of São Paulo that presents the characteristics of continuous process. The results of this application is presented, enfasizing the results obtained, it was obtained 21% of reduction in the screp indicator and 14% in the midium time of the set up and also some comments about the application of the lean production in these kinds of companies.

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