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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.
31

The Decomposition of Butyl Acetates over Charcoal Catalyst

Pettit, Paul J. 12 1900 (has links)
<p> This thesis presents an experimental study of the decomposition of the four isomers of butyl acetate over charcoal catalyst in a fixed bed reactor. The research attempts to determine the kinetics and mechanism of butyl acetate decomposition over a high surface area, non-selective catalyst, and to compare the catalyzed reactions of butyl acetates with their gas-phase reactions. When interpreting the experimental kinetic data it is hypothesized that each of the butyl acetates follows the same mechanism when reacting on charcoal. The best theoretical equation for expressing the rate of butyl acetate reaction was selected from the Langmuir-Hinshelwood equations.</p> / Thesis / Doctor of Philosophy (PhD)
32

An attempt to relate the surface tension to the concentration and the degree of polymerization of nitrocellulose dissolved in n-butyl acetate

Jones, T. G. January 1943 (has links)
On the basis of the present data it would seem that there is no marked relationship between the surface tension and the degree of polymerization of nitrocellulose solutions of normal butyl acetate as determined by the Du Nouy method. It should be noted that no great precision is present in the recorded data. A slight change in surface tension due to a difference in the degree of polymerization could easily be more than offset by errors in measurement. The solutions become much more viscous with increased concentration. This limited the range over which the surface tension could be measured with any degree of accuracy. For with highly viscous solutions the ring would be pulled slowly from the surface making it extremely difficult to determine the exact force required for the break. A second effect was that with increasing concentration a film of the solution adhered across the ring. The data indicates that there is no great change in the surface tension with varying concentration within the range studied. / M.S.
33

Characterization of the genes and gene products of the acetate-activating enzymes and a novel iron-sulfur flavoprotein from Methanosarcina thermophila strain TM-1

Latimer, Matthew T. 20 October 2005 (has links)
The genes encoding the acetate kinase and phosphotransacetylase enzymes from <i>Methanosarcina thermophila</i> were isolated from a genomic library on a fifteen kilobase fragment The genes are located adjacent to one another, with the phosphotransacetylase gene (<i>pta</i>) directly upstream of the acetate kinase gene (<i>ack</i>). The two genes were sequenced, along with a third Open Reading Frame (designated <i>orfY</i>). The <i>orfY</i> gene appears to encode a novel protein whose physiological function has yet to be determined. / Ph. D.
34

Efeitos do acetato de deslorelina sobre a produção in vivo e in vitro de embriões de gatas domésticas /

Ackermann, Camila Louise. January 2015 (has links)
Orientador: Maria Denise Lopes / Banca: Fernanda da Cruz Landim / Banca: Carlos Roberto Teixeira / Banca: Lílian Rigatto Martins / Banca: Nei Moreira / Resumo: O acetato de deslorelina promove uma contracepção de longa duração segura e eficaz, porém a reversibilidade espontânea é progressiva e assincrônica. O objetivo geral foi avaliar os efeitos do acetato de deslorelina sobre a produção in vivo e in vitro de embriões de gatas domésticas. Para tanto foram realizados 2 experimentos. Experimento 1: Objetivou-se avaliar a taxa de produção de embriões in vitro em gatas tratadas com acetato de deslorelina. Foram utilizadas 21 fêmeas (Tratado n=11 e Controle n=10). Onze gatas receberam um implante de deslorelina (4,7mg/animal) e o tratamento durou 6 meses. Após o tratamento, todas as fêmeas (Tratado e Controle) foram submetidas à OSH para que seus ovários fossem incluídos em rotinas de produção de embriões in vitro (PIV). A taxa de recuperação de COC foi submetida ao teste t de Student. As taxas de clivagem e blastocisto foram expressas em porcentagem e submetidas ao teste exato de Fisher. Todas as análises foram realizadas no programa GraphPad v5.0, P<0.05. Uma gata apresentou galactorréia e foi retirada do grupo experimental. Foram obtidos 184 COC grau I, a taxa de clivagem foi em média de 55,97% (total de 103 mórulas) e de blastocisto de 33,99% (total de 33 blastocistos) no grupo Controle. Já no grupo Tratado foram obtidos 83 COC grau I e a taxa de clivagem foi em média 60,24% (total de 50 mórulas) e de blastocisto foi de 36% (total de 18 blastocistos). Só houve diferença estatística entre os grupos na taxa de recuperação de COC grau I. A taxa de recuperação de COC foi menor em gatas tratadas, porém a PIV apresentou taxas similares à de fêmeas não tratadas. Devem-se considerar as variações individuais no grupo tratado. Experimento 2: Objetivou-se avaliar a produção de embriões in vivo, a taxa de concepção, bem como a presença de receptores de estrógeno e progesterona no útero, e receptores de LH e FSH em ovários de gatas submetidas ao tratamento com... / Abstract: Deslorelin acetate promotes a long, safe and efficient contraception; however reversibility is consider progressive and asynchronous. We aim to evaluate the effects of deslorelin acetate on in vitro and in vivo embryo production in domestic cats. For that 2 experiments were performed. Experiment 1: The objective was to investigate the effect of contraceptive treatment with deslorelin acetate in in vitro embryo production and oocyte recovery in domestic queens. Twenty one queens (Treated n=11 and Control n=10) and one tom were used. Eleven queens were treated with deslorelin acetate (4.7mg/animal) during 6 months. Thereafter all females (treated and control) were spayed and the ovaries were included in in vitro embryo production routines (PIV). Rate of COC recovery was submitted to t test. Cleavage and blastocyst rate were expressed in percentage and submitted to Fisher's exact test. All analyses were performed in GraphPad Pisma v5.0 program, P < 0.05. One female developed galactorrhoea and was removed from experimental group. In Control group we recovered 18.4±3.21 of COC I, cleavage rate was 55.97% and blastocyst rate was 33.99%.In Treated group we recovered 8.3±1.15 of COC I, cleavage rate was 60.24% and blastocyst rate was 36%. Statistical difference was only observed in COC recovery, were treated cats had fewer than control group. Although we didn't found differences on embryo production, individual variation must be considered. Experiment 2: We aimed to evaluate in vivo embryo production, trough pregnancies, and also identify estrogen (ER-α) and progesterone (PgR) receptors in uterus and FSH (FSH-R) and LH (LH-R) receptors in ovaries from queen treated with deslorelin acetate. We used 25 queens and one tom, 15 queens were treated with deslorelin acetate (4.7mg/animal) for 3 months. After that, all implants were removed and estrous and ovulation was induced. After 24hs five queens were maintained with one tom and mating was ... / Doutor
35

Characterization of acetate metabolism genes in Sinorhizobium (Rhizobium) meliloti

Thaha, Fathuma Zuleikha. January 1999 (has links)
Fifteen mutants of Sinorhizobium (Rhizobium ) meliloti unable to utilize acetate as a sale carbon source (Ace-) were characterized in this study. Merodiploid complementation tests showed that nine of these mutations were in loci distinct from previously described gluconeogenic loci. The chromosomal locations of the mutations were determined, and complementing clones were isolated from the cosmid library of S. meliloti genomic DNA. The mutants were placed into four groups (I--IV) based on genetic linkage in phage co-transduction. None of the mutations were in glyoxylate shunt enzyme-encoding genes. Nucleotide sequence analysis of ace mutants from Groups III and IV showed mutations in genes encoding acetyl-CoA synthetase ( acsB) and anaerobic coproporphyrinogen III oxidase (hemN ) respectively. Cell extracts of the hemN mutant exhibited double the isocitrate lyase levels of the wild type. The acsB mutant lacked acetyl-CoA synthetase activity and had an interesting growth phenotype; it was able to grow on low concentrations of acetate only. (Abstract shortened by UMI.)
36

Acetate and poly-b-hydroxybutyrate (PHB) metabolism by the activated sludge floc community of a hardwood Kraft pulp and paper mill

Pouliot, Cédrick January 2005 (has links)
This research followed acetate carbon (C) uptake, metabolism, and fate through a typical modern Kraft pulp and paper mill AS system. Freshly collected mill biomass (AS floc suspensions) was placed under conditions representing four key phases of AS biotreatment: (1) initial acetate uptake by aerated starved AS; (2) ongoing acetate uptake; (3) aerobic metabolism of acetate-loaded AS in acetate-stripped effluent; and (4) anaerobic, settled biomass metabolism. Conditions mimicked the mill system as closely as possible. Acetate carbon uptake kinetics and conversion to CO2, growth products, PHB, and secreted metabolites in each of the four phases were measured. The role of PHB synthesis in the initial stripping of acetate from mill effluent and the PHB production potential of this mill AS were also investigated. / Results showed that acetate was rapidly taken up by high-affinity systems in the AS. During the initial exposure of mill-starved AS, acetate greatly stimulated AS-O2 uptake, and was quickly converted to PHB and CO 2. Upon depletion of available effluent acetate, as occurs in the downstream sections of the aeration tank, O2-uptake rates decreased and the acetate-C stored in AS-PHB was slowly released as CO2, and partly used for growth. Under secondary clarifier-like anaerobic conditions, the AS released virtually no CO2. However, substantial amounts of PHB were used for growth under anaerobic conditions and a small proportion of the original acetate C exited the cells as organic acids.
37

Efeitos do acetato de deslorelina sobre a produção in vivo e in vitro de embriões de gatas domésticas / Deslorelin acetate on embryo production in vivo and in vitro in domestic cats

Ackermann, Camila Louise [UNESP] 25 June 2015 (has links) (PDF)
Made available in DSpace on 2016-06-07T17:12:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-06-25. Added 1 bitstream(s) on 2016-06-07T17:16:53Z : No. of bitstreams: 1 000866056.pdf: 919821 bytes, checksum: 345a1b2e0d1838ead9a919f9d70b8236 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O acetato de deslorelina promove uma contracepção de longa duração segura e eficaz, porém a reversibilidade espontânea é progressiva e assincrônica. O objetivo geral foi avaliar os efeitos do acetato de deslorelina sobre a produção in vivo e in vitro de embriões de gatas domésticas. Para tanto foram realizados 2 experimentos. Experimento 1: Objetivou-se avaliar a taxa de produção de embriões in vitro em gatas tratadas com acetato de deslorelina. Foram utilizadas 21 fêmeas (Tratado n=11 e Controle n=10). Onze gatas receberam um implante de deslorelina (4,7mg/animal) e o tratamento durou 6 meses. Após o tratamento, todas as fêmeas (Tratado e Controle) foram submetidas à OSH para que seus ovários fossem incluídos em rotinas de produção de embriões in vitro (PIV). A taxa de recuperação de COC foi submetida ao teste t de Student. As taxas de clivagem e blastocisto foram expressas em porcentagem e submetidas ao teste exato de Fisher. Todas as análises foram realizadas no programa GraphPad v5.0, P<0.05. Uma gata apresentou galactorréia e foi retirada do grupo experimental. Foram obtidos 184 COC grau I, a taxa de clivagem foi em média de 55,97% (total de 103 mórulas) e de blastocisto de 33,99% (total de 33 blastocistos) no grupo Controle. Já no grupo Tratado foram obtidos 83 COC grau I e a taxa de clivagem foi em média 60,24% (total de 50 mórulas) e de blastocisto foi de 36% (total de 18 blastocistos). Só houve diferença estatística entre os grupos na taxa de recuperação de COC grau I. A taxa de recuperação de COC foi menor em gatas tratadas, porém a PIV apresentou taxas similares à de fêmeas não tratadas. Devem-se considerar as variações individuais no grupo tratado. Experimento 2: Objetivou-se avaliar a produção de embriões in vivo, a taxa de concepção, bem como a presença de receptores de estrógeno e progesterona no útero, e receptores de LH e FSH em ovários de gatas submetidas ao tratamento com... / Deslorelin acetate promotes a long, safe and efficient contraception; however reversibility is consider progressive and asynchronous. We aim to evaluate the effects of deslorelin acetate on in vitro and in vivo embryo production in domestic cats. For that 2 experiments were performed. Experiment 1: The objective was to investigate the effect of contraceptive treatment with deslorelin acetate in in vitro embryo production and oocyte recovery in domestic queens. Twenty one queens (Treated n=11 and Control n=10) and one tom were used. Eleven queens were treated with deslorelin acetate (4.7mg/animal) during 6 months. Thereafter all females (treated and control) were spayed and the ovaries were included in in vitro embryo production routines (PIV). Rate of COC recovery was submitted to t test. Cleavage and blastocyst rate were expressed in percentage and submitted to Fisher's exact test. All analyses were performed in GraphPad Pisma v5.0 program, P < 0.05. One female developed galactorrhoea and was removed from experimental group. In Control group we recovered 18.4±3.21 of COC I, cleavage rate was 55.97% and blastocyst rate was 33.99%.In Treated group we recovered 8.3±1.15 of COC I, cleavage rate was 60.24% and blastocyst rate was 36%. Statistical difference was only observed in COC recovery, were treated cats had fewer than control group. Although we didn't found differences on embryo production, individual variation must be considered. Experiment 2: We aimed to evaluate in vivo embryo production, trough pregnancies, and also identify estrogen (ER-α) and progesterone (PgR) receptors in uterus and FSH (FSH-R) and LH (LH-R) receptors in ovaries from queen treated with deslorelin acetate. We used 25 queens and one tom, 15 queens were treated with deslorelin acetate (4.7mg/animal) for 3 months. After that, all implants were removed and estrous and ovulation was induced. After 24hs five queens were maintained with one tom and mating was ... / FAPESP: 11/23318-0
38

Projeto conceitual de plantas alcoolquimicas / Alcoholchemistry plants conceptual projects

Araujo, Maria Cristina de 12 April 2009 (has links)
Orientador: Rubens Maciel Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-14T23:31:29Z (GMT). No. of bitstreams: 1 Araujo_MariaCristinade_D.pdf: 4065540 bytes, checksum: 5894b9d4ab32275a40a9981e9744c1b7 (MD5) Previous issue date: 2009 / Resumo: Este trabalho tem por finalidade propor o projeto conceitual de plantas alcoolquímicas a partir de dados experimentais de reações químicas em escala de laboratório, utilizando Simulador Comercial, no caso Aspen Plus (Versão 2006). A exaustão das fontes de energia baseada em combustíveis fósseis e as preocupações ambientais em torno do aumento do dióxido de carbono e do aquecimento global são crescentes. Assim, o uso de energia renovável/sustentável é uma realidade. Nos últimos trinta anos, a produção de etanol da cana-de-açúcar no Brasil avançou para 17 bilhões de litros, com perspectivas de atingir 35,7 bilhões de litros em 2012-2013 de acordo com dados UNICA (União da Indústria de Cana-de-Açúcar). O Brasil tem a grande oportunidade de desenvolver e usar derivados do etanol, ou seja, fazer uso inteligente da chamada Alcoolquímica e a partir de dois átomos de carbono gerar todos os produtos feitos à base de petróleo, de forma integrada ambientalmente e de maneira capaz a se ter uma alta sustentabilidade global. A Planta de Esterificação do Etanol com ácido acético em fase vapor empregando o pentóxido de nióbio hidratado (nome comercial: ácido nióbico) teve como suporte a pesquisa de Oliveira (1991) e Oliveira e Nascimento (1991) quanto à cinética para o reator. As plantas projetadas tiveram como escopo a alta pureza dos produtos e reagentes remanescentes no processo com a finalidade de serem reciclados e responderem a qualidade tanto ambiental quanto comercial. Foi seguida a premissa de se procurar usar apenas um solvente, além da água que, ao contrário da maioria dos processos industriais, ao final é obtida com alta de pureza. Foram projetadas duas plantas denominadas configuração e configuração S. Da série de testes experimentais realizados por Araújo (2003) e Araújo e Sprung (2003), foi escolhido o catalisador do tipo hidrotalcita calcinado a 650°C composto de cobalto e alumínio, uma vez que este foi mais seletivo em relação aos produtos obtidos (etileno, acetaldeído, acetato de etila, hidrogênio e traços de éter etílico). A planta usando este catalisador também gerou produtos com alta pureza como o acetato de etila, etileno e água, sendo o hidrogênio 100% puro e o acetaldeído com faixas de 95,5 a 99,9% tendo como resíduos os azeótropos formados com a água e o éter etílico, portanto não separáveis por técnicas convencionais. / Abstract: The objective of this work has the purpose to conceptually design alcohol chemistries plants from experimental reactor data being used commercial simulator (Aspen Plus). The exhaustion of the sources of energy based on fossil fuels and the environmental concerns about the increase of the carbon dioxide and of the global heating are growing. In this way, the use of renewable and maintainable energy is a reality. In the last thirty years, the production of ethanol of the sugar-cane in Brazil moved forward 17 billion liters, with perspectives of reaching 35,7 billion liters in 2012-2013 in agreement with data from UNICA ((Union of the Industry of Sugar-Cane). Brazil has the large opportunity to develop and to use derived of the ethanol, in other words, to do intelligent use of the call Alcohol-chemistry and starting from two atoms of carbon to generate large quantity of products originally based on petroleum, in way integrated with the environment. The Plant of ethanol esterification with acetic acid in vapor phase using the pentoxide niobic hydration (trade name: acid niobic) had as support the works of Oliveira (1991) and Oliveira and Nascimento (1991) in relation to the kinetics for the reactor. The projected plants had as mark the purity of the products and of the remaining reagents in the process with the purpose of recycle them and they answer the environmental and commercial qualities. The intention was to use only one solvent, besides the use of water that, contrarily to the most of the industrial processes, at the end, it is generated with high purity. Two plants were projected: the configuration ? and the configuration S . Of the series of tests accomplished by Araújo (2003) and Araújo and Sprung (2003), it was chosen the catalyst of the type hydrotalcite calcined at 650°C composed of cobalt and aluminum, because this was more selective in relation to the obtained products (ethylene, acethaldehyde, ethyl acetate, hydrogen and residues of ethyl ether). The plant using this catalyst also generated products with high purity as the ethyl acetate, ethylene and water being the hydrogen 100% pure and the acethaldehyde with strips from 95,5 to 99,9% having as residues the azeotropes formed with water and ethyl, which can not be separated by conventional processes. / Doutorado / Desenvolvimento de Processos Químicos / Doutor em Engenharia Química
39

Characterization of acetate metabolism genes in Sinorhizobium (Rhizobium) meliloti

Thaha, Fathuma Zuleikha. January 1999 (has links)
No description available.
40

Acetate and poly-b-hydroxybutyrate (PHB) metabolism by the activated sludge floc community of a hardwood Kraft pulp and paper mill

Pouliot, Cédrick January 2005 (has links)
No description available.

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