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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

Algumas propriedades físico-químicas e de engenharia de uma argila orgânica do Recife. / Some physico-chemical and engineering proprieties of an organic clay from Recife.

CARVALHO, João Batista Queiroz de. 30 September 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-09-30T14:07:04Z No. of bitstreams: 1 JOÃO BATISTA QUEIROZ DE CARVALHO - DISSERTAÇÃO PPGECA 1975..pdf: 23722015 bytes, checksum: 8472b04995abaef083f89dbe9bba109e (MD5) / Made available in DSpace on 2018-09-30T14:07:04Z (GMT). No. of bitstreams: 1 JOÃO BATISTA QUEIROZ DE CARVALHO - DISSERTAÇÃO PPGECA 1975..pdf: 23722015 bytes, checksum: 8472b04995abaef083f89dbe9bba109e (MD5) Previous issue date: 1975-03 / 0 propósito desta dissertação foi estudar "algumas propriedades físico-químicas e de engenharia de uma argila orgânica" que forma parte do subsolo da cidade do Recife. As "amostras indeformadas" foram retira das do subsolo pelo uso de tubos de parede fina sem costura conhecidos por tubos tipo "Shelby". Os resultados dos ensaios de laboratório foram obtidos com amostras retiradas ao longo da camada de argila orgânica com intervalos de 1,0 metro. Os ensaios, teor de umidade de campo, limites de Atterberg, análise granulométrica , área específica , pH, composição mineralógica, adensamento e triaxial não consolidado não drenado, permitiram não somente o estudo do solo em função da profundidade mas também sua caracterização. O estudo mostra que a homogeneidade e uniformidade da "argila orgânica" é provavelmente função da variação do teor de matéria orgânica. O solo é caracterizado como uma "argila orgânica" com baixo teor de matéria orgânica finalmente dividida, apresentando alta plasticidade, composta predominantemente do argilo-mineral caulinita, normalmente adensada e de baixa sensibilidade. Análise de regressão linear foi usada para explorar possíveis correlações entre os valores dos diferentes ensaios realizados. Isto mostra que, dentro das limitações do estudo, existem correlações entre os parâmetros medidos. Propõe-se que estas correlações sejam usadas preliminarmente para avaliar as propriedades de engenhar i d do solo estudado. / The purpose of this dissertation was to study some physico-chemical and engineering properties of an "organic clay" which forms part of the soil profile underlying the city of Recife. Undisturbed specimens were recovered from the subsoil by the use of seamless, thin walled steel tubes known as "Shelby type tubes". Results during the laboratory testing programme were obtained from specimens recovered at 1 m intervals along the depth of the organic clay strata. Field moisture content, Atterberg limits, grain size distribution, specific gravity, specific surface, pH, minera1ogica1 analysis, consolidation and unconsolidated undrained triaxiol tests allowed not only the study of the soil as a function of depth but its characterization as well. The study shows that the homogeneity and uniformity of the "organic clay" is probably a function of the variation of organic matter content.- The soil is characterized as a: "soft organic clay with traces of highly divided inactive organic matter, exhibiting high plasticity, composed predominantly of kaolinite cl y mineral, normally consolidated and of low sensitivity". Linear regression analysis was used to explore possible correlations between the values of the different tests carried out. It is shown that, within the limitations of the study, statistical relations do exist between the parameters measured. It is proposed that these correlations may be used for preliminary evaluation of the engineering properties of the soil studied.
32

Aplicação de computação evolucionária na mineração de dados físico-químicos da água e do solo

Guimarães, Alaine Margarete [UNESP] 05 December 2005 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:31:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-12-05Bitstream added on 2014-06-13T19:20:52Z : No. of bitstreams: 1 guimaraes_am_dr_botfca.pdf: 960847 bytes, checksum: a716ab7dc09b4f9f246b403c778558b1 (MD5) / Essa tese apresenta o desenvolvimento de um sistema de mineração de dados baseado na técnica de computação evolucionária denominada Algoritmos Genéticos. O sistema resultante, de nome MinAG, realiza a tarefa de classificação de dados contínuos e destina-se a minerar dados físico-químicos do solo e da água. Os padrões de comportamento dos atributos minerados são apresentados no formato SE-ENTÃO, facilitando a compreensão da informação descoberta. Foram definidos alguns requerimentos e restrições para o uso desse sistema relacionados às características do arquivo de dados possível de ser minerado. O MinAG adota o conceito de computação em grid, o que propicia para que mais e melhores resultados sejam obtidos. Os testes realizados permitiram concluir que o sistema executou as tarefas definidas para o mesmo e gerou resultados corretos ao minerar as bases de dados a que se propôs, atingindo, portanto os objetivos dessa tese. Foram realizados dois estudos de casos. No primeiro foi utilizada uma base de dados brasileira sobre dados físico-químicos do solo obtidos por equipamentos de agricultura de precisão na região de Campos Novos Paulista - SP. No segundo estudo de caso usou-se uma base de dados de qualidade de água do estado da Flórida - EUA. Em ambos os casos o sistema foi capaz de atingir seu objetivo encontrando padrões de comportamento nos dados. Pode-se concluir que o sistema MinAG apresenta-se como uma nova maneira de analisar a correlação entre os elementos físico-químicos do solo e da água. Esse sistema não deve ser entendido como um substituto de métodos de análise tradicionais, como a estatística. Sua função é servir como uma ferramenta adicional na geração de informações para auxílio à compreensão do comportamento existente nos dados. / This thesis presents the data mining system development based on an evolutionary computation technique named Genetic Algorithms. The MinAG system performs the continuous data classification task and mines water and soil physico-chemical datasets. The patterns discovered by mining the attributes are presented using the IF-THEN rule format. It makes it easier to understand the information discovered. Some requirements and restrictions related to the dataset features were defined in order to use the system. MinAG adopts the grid computing concept in order to produce more and better results. By the evaluation system, it was possible to conclude that it is able to perform the proposed tasks and produces correct results when mining the datasets. Therefore, the system reached the thesis goals. Two case studies were performed. In the first one, a Brazilian dataset related to soil physico-chemical properties was used. The data was obtained in Campos Novos Paulista - SP by Precision Agriculture equipment. In the second case study, a Florida - USA water quality dataset was utilized. The system discovered behavior patterns achieving the goals in both cases. The MinAG system presents a new way to analyse the correlation between the water and soil physico-chemical attributes. This system is not a substitute for traditional methods such as statistics. In fact, it is an auxiliary tool to generate information in order to help understand the behavior between data.
33

Planejamento, obtenção e caracterização de novas formas sólidas de fármacos tuberculostáticos / Design, production and characterization of new solid forms of tuberculostatic drugs

Luan Farinelli Diniz 29 November 2017 (has links)
As propriedades no estado sólido de um insumo farmacêutico ativo (IFA) estão diretamente relacionadas com a eficácia terapêutica de um medicamento. Entre todas as propriedades físicas e químicas, que são dependentes doarranjo cristalinodo IFA, destaca-se a solubilidade e a estabilidade, que são as características mais importantes de um fármaco, na medida em que podem alterar a biodisponibilidade. Dentro dessa perspectiva, a engenharia de cristaistem cada vez mais se consolidado como uma estratégia para aperfeiçoar as propriedades no estado sólido de um IFA. Neste trabalho, oito novas formas sólidas cristalinas, entre sais e cocristais, dos fármacos com ação anti-tuberculose etionamida (ETH), etambutol (ETB) e isoniazida (INH), foram preparadas e tiveram suas estruturas cristalinas determinadas por difração de raios X por monocristal. Além disso, todas as modificações cristalinas obtidas foram caracterizadas por difração de raios X por policristais, espectroscopia vibracional no infravermelho e Raman, calorimetria exploratória diferencial, termogravimetria e microscopia ótica térmica. Por fim, estudos de solubilidade em equilíbrio e de estabilidade em atmosfera úmida também foram realizados. A nova modificação cristalina da ETH, o sal nitrato de ETH, foi planejada visando melhorar a solubilidade aquosa deste IFA (∼0,4 mg mL-1). Este é o primeiro relato de uma estrutura de ETH que cristalizou com quatro independentes pares iônicos (ETH+/NO3-) na unidade assimétrica. A análise do empacotamento cristalino e das interações intermoleculares permitiu estabelecer os atributos estruturais que explicam a menor estabilidade térmica e a elevada solubilidade (cerca de 300 vezes maior) deste sal, em comparação com a forma neutra da ETH. A preparação dos novos sais de ETB foi feito considerando o cárater básico da molécula, o que permitiu a obtenção de três novos sais a partir da reação do ETB com os ácidos oxalico, maleico e tereftálico. O desenho dessas formas sólidas teve como principal objetivo minimizar os efeitos da elevada higroscopicidade do ETB, que é tão prejudicial para formulações farmacêuticas. Este objetivo foi alcançado, uma vez que o sal oxalato de ETB, reportado neste trabalho, mostrou ser não-higroscópico. Por fim, quatro novos cocristais da INH, sendo dois cocristais polimórficos, foram preparados por meio de reações estequiométricas deste IFA com ácidos carboxílicos aromáticos derivados do ácido benzóico. O desenho dessas novas modificações cristalinas teve como intuito principal explorar a diversidade de síntons supramoleculares formados entre a INH e moléculas contendo o grupo COOH. A análise dos empacotamentos cristalinos das formas I e II do cocristal INH-PABA, mostrou que este é um típico caso de polimorfismo orientacional. Portanto, os resultados desta dissertação trazem importantes contribuições científicas para a diversidade de formas sólidas, apresentando revelância para o setor farmacêutico no que se refere ao desenvolvimento de novas formulações contendo fármacos anti-tuberculose. / Solid state properties of an active pharmaceutical ingredients (API) are directly related to drug performance. Among all physical and chemical properties dependent on the crystal arrangement of a drug, stability and solubility are the main ones that alter its bioavailability. In this sense, crystal engineering is a strategy to improve solid state properties of drugs. In this work, eigth new multicomponent solid forms (salts and cocrystals) of the tuberculostatic drugs ethionamide (ETH), ethambutol (ETB) and isoniazid (INH) were prepared and their crystal structures were elucidated by single crystal X-ray diffraction. In addition, the crystal modifications were also characterized by powder X-ray diffraction, infrared and Raman vibrational spectroscopy, differential scanning calorimetry, thermogravimetry and Hot-stage microscopy. Finally, equilibrium solubility studies and stability experiments in humid atmosphere were also performed. The new supramolecular modification of ETH, ethionamide nitrate salt, was designed in order to improve the aqueous solubility of the API (∼0.4 mg ml-1). This salt is the first ETH structure that has been crystallized with four independent ionic pairs (ETH+/NO3-) in the asymmetric unit. The analysis of crystal packing and intermolecular interactions allowed to establish the structural attributes that explain the lower thermal stability and high solubility (about 300 times higher) of this salt compared to the neutral ETH form. Due its high hygroscopicity, ETB is known for catalyzing the degradation of isoniazid and rifampicinin pharmaceutical formulations. In order to avoid or even minimize these mutual drug-drug interactions, in this work we have focused on the development of less hygroscopic multicomponent solid forms of ETB. The preparation of the new ETB crystal modifications was carried out considering the pKa values of the molecule, which allowed the design of three new salts (namely oxalate, maleate and terephthalate). These salts were obtained from the reaction of ETB with the carboxylic acids: oxalic, maleic and terephthalic. The hygroscopic nature of these salts was evaluated and all of them were found to be hygroscopic, with exception of ETB oxalate. Finally, four novel INH cocrystals, being two polymorphic forms, with aromatic carboxylic acids derivatives were rationally prepared. The design of these crystal forms aimed to explore the diversity of supramolecular synthons formed between INH and molecules containing COOH. The crystal packing analysis of the INH-PABA cocrystals (polymorphs I and II), showed that this is a typical case of orientational polymorphism. Therefore, the scientific contributions of this work show the diversity of the solid forms and define candidates to new anti-tuberculosis API\'s solid formulations.
34

ADSORÇÃO DE INTERFERENTES ENDÓCRINOS EM GRAFENO E DERIVADOS: AVALIAÇÃO TEÓRICA E EXPERIMENTAL

Jauris, Iuri Medeiros 21 November 2016 (has links)
Submitted by MARCIA ROVADOSCHI (marciar@unifra.br) on 2018-08-20T12:17:09Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_IuriMedeirosJauris.pdf: 8625676 bytes, checksum: 6980ea50a786db7523d0559ac05b09bb (MD5) / Made available in DSpace on 2018-08-20T12:17:09Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_IuriMedeirosJauris.pdf: 8625676 bytes, checksum: 6980ea50a786db7523d0559ac05b09bb (MD5) Previous issue date: 2016-11-21 / Various chemical pollutants and substances named endocrine disruptors compounds (EDCs) has become commonly detected in wastewater and even in drinking water in many countries. In contrast the adsorption technique has been considered by many researcher as a promising method to treatment and purification of wastewater, mainly due to its ease of operation, high efficiency and low cost. Meanwhile, carbon nanomaterials such as nanotubes, and graphene, have been reported in the literature as promising materials to adsorb and removing various types of contaminants from wastewater. From this perspective, the main goal of this study was the evaluation of the use of graphene, functionalized graphene and reduced graphene oxide (rGO), in the adsorption and removal of drugs in aqueous medium. The removal efficiency was measured using diclofenac sodium (DCL) and nimesulide (NIME) in aqueous solutions and analizing sorption equilibrium conditions as well as kinetics and adsorption isotherms in the rGO. At the same time, through ab initio calculations, computational simulations were carried out to better understand how the structural and electronic characteristics of the adsorbent material can influence the adsorption process. Thus, through the batch experiments, it was found that the rGO showed a good ability to successfully remove NIME and DCL drugs from aqueous solutions. The maximum percentage removal of DCL by rGO was 80.4% and 79.3% for the initial concentrations of 40 and 70 mg.L-1, respectively. The maximum sorption capacity for adsorption of the DCL drug at 25ºC was 59.67 mg.g-1. The maximum percentage removal of NIME by rGO was 92.2% and 82.9% for the initial concentrations of 40 and 70 mg.L-1, respectively. The thermogravimetric and FTIR spectroscopy analyzes revealed that DCL and NIME was successfully adsorbed by rGO. In addition, theoretical results showed that the interaction between DCL and NIME with pristine or functionalized graphene, occurs by physical adsorption, being maintained mainly due to π-π interactions and hydrogen bonding. The results provide valuable information for better understanding the behavior of physicochemical properties in the evaluated interactions. Based on these results, the ab initio calculations and the adsorption experiments point out that the graphene and functionalized graphene or rGO are promising materials for extracting DCL and NIME drugs from wastewater effluents. / A detecção de poluentes químicos diversos e substâncias conhecidas com interferentes endócrinos (IEs) em águas residuais e até mesmo na água potável, tem se tornado cada vez mais frequente em inúmeros países. Em contrapartida a técnica de adsorção, tem sido considerado por muitos pesquisadores como um método promissor de tratamento e purificação da água proveniente de efluentes, devido, principalmente, a sua facilidade de operação, alta eficiência e baixo custo. Paralelamente, os nanomateriais de carbono, tais como nanotubos e o grafeno vêm sendo reportados na literatura como materiais de grande capacidade para adsorção e remoção de diversos tipos de produtos químicos de águas residuais. Nesse sentido, o foco desse estudo foi a avaliação do uso do grafeno, grafeno funcionalizado e óxido de grafeno reduzido (rGO), na adsorção e remoção de fármacos em meio aquoso. A avaliaçao da eficiência de remoção foi conduzida empregando-se diclofenaco sódico (DCL) e a nimesulida (NIME) em soluções aquosas e avaliando-se as condições de equilíbrio de sorção e também cinética e isotermas de adsorção no rGO. Paralelamente, através de cálculos de primeiros princípios, foram realizadas simulações computacionais para melhor compreensão de como as características estruturais e eletrônicas do material adsorvente, podem influenciar no processo adsortivo. Assim, através dos experimentos em batelada, observou-se um percentual de remoção máximo do DCL pelo rGO de 80,4% e 79,3% para as concentrações iniciais de 40 e 70 mg.L-1. A capacidade máxima encontrada de adsorção do DCL pelo rGO a 25ºC foi de 59,67mg.g-1. O percentual de remoção máximo da NIME pelo rGO foi 92,2 % e 82,9% para as concentrações iniciais de 40 e 70 mg.L-1 . O pH foi fixo em 10,0 para todos os experimentos. As análises termogravimétricas para adsorção do DCL e NIME em rGO, e de espectroscopia FTIR para adsorção da NIME em rGO, revelaram que os fármacos foram adsorvidos com sucesso pelo rGO. Em adição os resultados teóricos mostraram que a interação do DCL e da NIME com o grafeno puro e os grafenos funcionalizados ocorreram através da adsorção física, sendo essa mantida em grande parte devido às interações do tipo π-π e ligações de hidrogênio. Os resultados obtidos fornecem subsídios para a melhor compreensão do comportamento das propriedades físico-químicas nas interações avaliadas. Baseado nesses resultados, os cálculos de primeiros princípios e os experimentos de adsorção revelaram que o grafeno puro, grafeno funcionalizado, ou rGO, são materiais promissores para remoção dos fármacos DCL e NIME de soluções aquosas.
35

Mapeamento e modelagem edafoclimática  da produtividade de plantações de Eucalyptus no sul do estado de São Paulo / Mapping and edaphoclimatic modeling of productivity of Eucalyptus plantations at south of São Paulo State

Clayton Alcarde Alvares 18 May 2011 (has links)
O estudo do potencial biológico do ecossistema florestal torna-se essencial quando o objetivo é o seu manejo racional, visando a maximização da produtividade, e evitando-se a exaustão dos recursos do sítio florestal. Na área florestal é comum a aplicação de modelos que projetam o futuro do povoamento, pois desta forma pode-se tomar as decisões apropriadas a cerca do manejo a ser seguido. Dentre outros modelos, o 3-PG foi testado para inúmeras espécies florestais e em diversas condições edafoclimáticas, e tem sido reportado, por unanimidade, como uma poderosa ferramenta para auxiliar o manejo de povoamentos florestais. O objetivo desse estudo foi: calibrar, validar e simular a produtividade de plantações clonais de Eucalyptus com o uso do modelo 3-PG integrado a um sistema de informações geográficas. Foram selecionadas 20 parcelas de inventário que continham o material genético C219H (Eucalyptus grandis x E. urophylla) plantados no mesmo espaçamento de 3 x 3m e de mesma idade, com data de plantio no ano 2000, na região de Capão Bonito, sul do estado de São Paulo. Em cada parcela foram realizadas avaliações edáficas, dendrométricas e nutricionais em três árvores médias. A incorporação das características do relevo apresentou diferença no mapeamento da radiação global, principalmente no inverno, onde os efeitos do relevo foram elevados, apresentando diferenças de até 147%, em relação ao relevo plano. O número de geadas mensais foi determinado pela temperatura média mínima mensal, aprensentando uma relação linear negativa. A maioria das variáveis de solos analisadas aproximou-se da distribuição lognormal de freqüências. Na análise geoestatística, as variáveis relacionadas à fertilidade do solo apresentaram maiores alcances de dependência espacial no horizonte A, indicando que há maior homogeneidade na distribuição dos nutrientes na camada superficial do solo. A CTCefetiva apresentou relação exponencial positiva com o volume de madeira. Paralela a essa curva, foi proposta uma equação relacionando o índice de fertilidade do modelo 3-PGIS e esse atributo do solo. O teor de argila exerceu forte influência sobre os teores de água na capacidade de campo e no ponto de murcha permanente, por conseguinte, na disponibilidade de água dos solos. A máxima biomassa de fuste, encontrada nos povoamentos florestais manejados com elevado padrão tecnológico, relacionou-se diretamente com o teor argila+silte. Essa mesma propriedade do solo, exerceu influência na densidade da madeira. Sítios de maiores produtividades, por conseguinte, de maior teor de argila+silte, resultaram em árvores de menor densidade básica. Os teores foliares de N, Mg, Cu e Zn, aumentaram exponencialmente com o teor de argila, da mesma forma que o DAP e a biomassa de folhas. Por outro lado, os teores foliares de P, K, Ca, S, B, Fe e Mn apresentaram relação oposta, decresceram exponencialmente nos solos mais argilosos. Foi obtida a calibração, a validação e aplicação do modelo 3-PGIS nas condições edafoclimáticas de Capão Bonito em povoamentos clonais do material genético C219H. No geral, o modelo 3-PGIS, apresentou bom desempenho, principalmente nas estimativas do volume de lenho com casca e da biomassa de fuste. As simulações do DAP e do IMA foram mais dispersas. / The study of the biological potential of forest ecosystems become essential when the objective is rational management, aiming productivity maximization, and avoiding resource exhaustion of the forest site. Forest sector usually apply models to simulate the future of the stand, aiming make appropriated decisions regarding the management to be followed. Among other models, 3-PG was tested for several forest species across different edaphoclimatic conditions, and has been reported unanimously, as a powerful tool to help on forest stands management. The objective of this study was: calibrate, validate and simulate productivity of clonal Eucalyptus plantations using 3-PG model integrated with a geographical information system. Twenty inventory plots were selected containing genetic material C219H (Eucalyptus grandis x E. urophylla) planted on spacing 3 x 3m, even aged, with planting date at 2000, Capão Bonito region, south of São Paulo state. On each plot were evaluated edaphic, dendrometric and nutritional variables on three average trees. Incorporation of relief characteristics resulted in differences on global radiation mapping, mainly during winter, where the effects of relief were elevated, showing up to 147% comparing to flat relief. Number of frosts per month was determined by monthly mean minimum temperature, with a negative linear relation. Most of soil variables evaluated showed a log-normal frequency distribution. At geostatistical analysis, variables related to soil fertility presented higher reaches of spatial dependency at A horizon, indicating higher homogeneity on nutrient distribution at superficial soil layer. The effective CEC showed positive exponential relation with wood volume. Parallel to that curve, we proposed an equation relating the fertility index of 3-PGIS and that soil attribute. Clay content showed strong influence on water levels at field capacity and wilting point, and as consequence, on soil water availability. Stem maximum biomass, observed on forest stands, managed with high technological standards, related directly with clay+silt contents. Same soil property affected wood density. High productivity sites, as consequence, with higher clay+silt contents, resulted in trees with lower wood density. Leaf level of N, Mg, Cu and Zn increased exponentially with clay content, like DBH and foliage biomass. Otherwise, leaf level of P, K, Ca, S, B, Fe and Mn showed opposite relation, decreasing exponentially on clayey soils. Calibration, validation and application of 3-PGIS were obtained for Capão Bonito edaphoclimatic conditions, on clonal stands of the genetic material C219H. Overall, 3- PGIS model showed good performance, mainly on estimative of stem plus bark volume and stem biomass. Simulations of DBH and MAI were dispersing.
36

Supported metal catalysts for friedel-crafts alkylation

Hlatywayo, Tapiwa January 2013 (has links)
Doctor Educationis / The research focused on the synthesis, characterisation and activity of zeolite supported metal catalysts for the Friedel-Crafts alkylation of benzene with t-butyl chloride. Alkyl benzenes are traditionally produced via systems that employ the use of Lewis acids or strong mineral acids. There have been widespread concerns over these approaches based on their environmental impacts and separation difficulties. Recent approaches have endeavoured the much to use more environmentally eco-friendly systems and zeolites have proved to be versatile support materials. The use of zeolites has also shown to greatly improve product selectivity as well as easing separation constraints. However the adoption of zeolites on large scale Friedel-Crafts alkylation has been hampered by the high cost of zeolite production from commercial sources. On the other hand fly ash has been found to be a viable starting material for zeolite synthesis. Apart from that South Africa is faced with fly disposal challenges and there is continual accumulation of fly ash at the coal fired power stations, which provide about 77 % of the power produced in the country. In this light the use of fly ash will help to reduce the disposal constraints as well as providing a cheap starting material for zeolite synthesis. In this study the hierarchical Zeolite X has been successfully synthesised from fly ash via a hydrothermal treatment. The zeolite was then loaded with Fe/Mn via two approaches namely liquid phase ion exchange and incipient wetness impregnation. For comparison purposes seasoned commercial support materials namely HBEA and MCM- 41 were also loaded with the same metals and characterised with various techniques namely; HRSEM, EDS, HRTEM, XRD, SAED, ICP-OES and N2 adsorption analysis, It was found from the characterisation undertaken that the integrity of the respective supports was generally retained upon metal loading. Both the ICP-OES and the EDS proved that the desired metals were successfully introduced onto the zeolitic support materials. The calculated percentage metal loading for the catalysts prepared via incipient wetness impregnation was closely related to the actual values obtained from the ICP-OES analysis for both the monometallic and the bimetallic catalysts (Fe/Mn). It was observed that the amount of metal that can be introduced on a zeolite via liquid phase ion exchange is largely dependent on the cation exchange capacity of the zeolite Supported metal catalysts for FC alkylation Page v and of the catalysts prepared using 0.25 M Fe solution it was found that Zeolite X had the highest Fe wt% loading of 11.4 %, with the lowest loading of 2.2 % obtained with the MCM-41 supported catalyst. The XRD patterns for the both HBEA and the MCM-41 supported metal catalysts resembled the patterns of the respective prestine support materials except in the case of catalysts with anFe wt % of more than 10, which exhibited peaks due to the Fe2O3 crystallites. In the case of the hierarchical Zeolite X, the metal loaded support had a significant reduction in the XRD peak intensities. The prepared catalysts were tested for the alkylation of benzene with t-butyl chloride. The benzene was also used as the solvent. The alkylation reaction was carried out in a round bottomed flask under reflux conditions and stirring at a temperature of 45 oC over a period of 5 h. A total of 18 catalysts was tested and the highest percentage conversion of 100 % was obtained with the 10%FeH after a reaction time of 2 h. The general trend obtained with the majority of the catalysts was characterised with a rapid initial increase and then steady state was achieved. Generally after a reaction time of 3 h almost all the catalysts had reached steady state in terms of the percentage conversion obtained. The outcomes reflect that the inclusion of Mn does not enhance the conversion but rather decreases it. It was also found that the Mn was not active in the alkylation of benzene as shown by the inactivity of the 10%MnM, where 10% by weight Mn was loaded on MCM-41. However the other monometallic catalysts containing Mn supported on Zeolite X and HBEA were found to be active. The activity is attributed to the presence of Brønsted acid sites in these zeolites which are not present in MCM-41. The selectivity studies reflect that the inclusion of Mn does slightly improve the selectivity towards the formation of the monoalkylated product (t-butyl benzene). The highest selectivity of 91.1 % was obtained with the 10%FeMnM after a reaction time of 4 h. MCM-41 supported catalysts had a relatively higher selectivity compared to the other supports. Considering the Fe monometallic catalysts tested it generally can be said that the yield were in the order HBEA > MCM-41 > Zeolite X. It however should be noted that the percentage yield is calculated from the conversion and selectivity percentages, this implies that the factors affecting these parameters will consequently affect the percentage yield obtained. Supported metal catalysts for FC alkylation Page vi The alkylation reaction was found to be characterised by the formation of two intermediate products which could not be identified. These products were formed during the transient start up stages of the reaction and would disappear from the reaction mixture with longer reaction times, and after 3 h in almost all the reactions studied the intermediates were not detected in the reaction mixture. The main products found were the monoalkylated product (desired product) and the para isomer (1,4-t-di-butyl benzene). There were no other dialkylated isomers or trialkylated products detected. The formation of the para isomer was usually after a reaction time of 2 h in most reactions. The research managed to show that the hierarchical Zeolites X can be synthesised from fly ash and ion exchange and incipient wetness impregnation are appropriate approaches that can be used to introduce Fe/Mn onto the support materials studied. The catalysts prepared were active to varying degrees in the Friedel-Crafts alkylation of benzene with t-butylchloride, with the exception of the 10%MnM which was found to be inactive.
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Essai d’optimisation du procédé de fabrication de la poudre de kishk libanais : conséquences sur les propriétés physicochimiques, microbiologiques, rhéologiques et sensorielles / Optimization of the manufacturing process of Lebanese kishk powder : effects on physico-chemical, microbiological and sensory properties

Salameh, Christelle 12 July 2016 (has links)
L’objectif de la thèse est de caractériser la poudre du kishk libanais, un lait fermenté traditionnel, et d’optimiser sa technologie de transformation dans une démarche d’industrialisation. Des échantillons de poudre de kishk traditionnel ont été collectés, et leurs propriétés physico-chimiques, rhéologiques, microbiologiques et sensorielles ont été étudiées, en fonction du type de lait utilisé. Il en résulte que le kishk préparé à base de lait de chèvre est plus riche en matières grasses que les autres types. La distribution granulométrique est très large, quel que soit le type de lait, avec présence simultanée de fines particules à forme irrégulière et d’agrégats de grande taille. Les particules de poudre sont revêtues d’une épaisse couche de lipides leur conférant un caractère cohésif et une grande résistance au cisaillement. Il s’avère aussi que la soupe de kishk présente un comportement rhéofluidifiant, et ses propriétés sensorielles sont fortement liées à la région de production et au type de lait. L’effet des conditions de production optimisée sur les propriétés de la poudre et de la soupe de kishk a été également étudié. Les résultats sont prometteurs et montrent que la structure de la poudre de kishk et son comportement rhéologique n’ont pas été altérés. En effet, les deux poudres de kishk présentent des propriétés rhéologiques quasi similaires, avec une faible aptitude à l’écoulement, malgré des différences au niveau de la composition chimique et la taille des particules. Au niveau rhéologique et sensoriel, la soupe de kishk issue de la production optimisée semble plus épaisse et consistante que la soupe traditionnelle, sans dépréciation notable des qualités organoleptiques du kishk. / The aim of this thesis is to characterize Lebanese kishk powder, a traditional fermented milk, and to optimize its processing technology. Samples of traditional kishk powder were collected, and their physicochemical, rheological, sensory and microbiological properties were studied based on the type of milk. As a result, kishk prepared with goat milk is richer in fat than other types. The particle size distribution is very wide, regardless of the type of milk, with simultaneous presence of fine irregularly shaped particles and large aggregates. Powder particles are coated with a thick layer of fat conferring a cohesive character and a high shear strength. Kishk soup has a shear-thinning behavior, and its sensory properties are strongly related to the production region and the type of milk. The effect of optimized production conditions on the properties of kishk powder and soup was also studied. The results are promising and show that the structure and rheological behavior of kishk powder were not altered. Indeed, the two kishk powders exhibit almost similar rheological properties, with low flowability, despite slight differences in chemical composition and particle size. Finally, kishk soup resulting from the optimized production seems thicker and consistent than traditional soup, without significant loss of the organoleptic properties of kishk.
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Adubação e biofortificação: caraterização química e física do arroz (Oryza sativa L.) / Biofortification and fertilization: chemical and physical characterization of rice (Oryza sativa L.)

Evelise Boliani 11 April 2012 (has links)
O arroz (Oryza sativa L.) é um dos cereais mais produzidos e consumidos no mundo, caracterizando como principal alimento para mais da metade da população mundial. Sua importância é destacada principalmente em países em desenvolvimento, tais como o Brasil, desempenhando papel estratégico em níveis econômico e social. Atualmente, é crescente o número de pesquisas que integram desde o melhoramento vegetal e o manejo da adubação até o aproveitamento dos nutrientes pelo organismo humano. O melhoramento de plantas pode ajudar a melhorar a dieta humana, com o desenvolvimento de plantas com maiores teores de vitaminas e micronutrientes. A introdução de produtos agrícolas biofortificados como o arroz, complementará as intervenções em nutrição existentes. Sendo assim, tornase imprescindível conhecer como as condições de cultivo influenciam na qualidade do grão e na importância para obtenção de um alimento com maior valor biológico e nutricional e com menores concentrações de antinutricionais. O objetivo deste trabalho foi analisar as características físico-químicas e nutricionais do arroz (Oryza sativa L.) integral, promovidas por diferentes adubações (experimento I) e aos grãos biofortificados (experimento II). Foram realizadas análises de composição centesimal, composição mineral, diálise in vitro de minerais, vitaminas do complexo B, conteúdo de compostos fenólicos e fitatos em grão, além das análises de parâmetros de qualidade em arroz como conteúdo de amilose aparente, propriedade de pasta e análise instrumental de cor. Os resultados obtidos no estudo assemelham-se aos citados nas literaturas quanto á composição centesimal e mineral, enfatizando a influência da cocção na composição nutricional do grão e em seus compostos como fenólicos e fitatos. Para o dialisado de cálcio e zinco no arroz biofortificado, a variação nos valores foi em média de 1,14% a 3,26% para cálcio e 0,80% a 3,43% para zinco. No experimento II, as perdas de vitaminas para o arroz integral biofortificado após o cozimento foi em torno de 33,4%, 52,17% e 76% para vitamina B1, vitamina B2 e vitamina B6, respectivamente. Por fim, conclui-se que a produção de variedades melhoradas seja através de adubações ou da escolha de melhores cultivares, que apresentam maior teor de minerais e vitaminas, foram eficientes para a melhora da disponibilidade nutricional dos grãos. / Rice (Oryza sativa L.) is one of most cereals produced and consumed in the world, characterized as the primary food for more than half the world population. Its importance is highlighted especially in developing countries such as Brazil, playing a strategic role in economic and social levels. There is increasing the number of studies since that integrate plant breeding and fertilizer management to use the nutrients the human body. Plant breeding can help improve the human diet, with the development of plants with higher levels of vitamins and micronutrients. The introduction of biofortified crops like rice, will complement existing nutrition interventions. Thus, it becomes essential to know as the cultivation conditions influence the quality of grain and the importance to obtain a food with higher nutritional and biological value and with lower concentrations of antinutritional. Threfore, the aim of this study was to analyze the pshycochemical and nutritional properties of rice (Oryza sativa L.) in full, caused by different fertilization (experiment I) and subjected to biofortification (experiment II). Were performed to analyze chemical composition, mineral, dialysis in vitro of minerals, vitamins B, content of phenolic compounds and phytates in grain, in addition to the analysis of quality parameters in rice as apparent amylase content, folder property and instrumental analysis of color. The results obtained in this study are similar to those cited in other literature as to the mineral and chemical composition, emphasizing the influence of cooking on the nutritional composition of grain and as phenolic compounds and phytates. For the dialysate calcium and zinc in rice biofortified crops, the variation in the values averaged 1.14% to 3.26% for calcium and 0.80% to 3.43% for zinc. Losses of vitamins to the rice after cooking was around 33.4%, 52.17% and 76% for vitamin B1, vitamin B2 and vitamin B6, respectively. Finally, we conclude that the production of improved varieties is through fertilization or the best choice of cultivars, that have a higher content of minerals and vitamins, were effective to improve the availability of nutrients of the grains.
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Optimizacija tehnološkog procesa proizvodnje funkcionalnog fermentisanog mlečnog napitka / Optimisation of functional fermented dairy beverage technology

Iličić Mirela 26 May 2010 (has links)
<p>U okviru doktorske disertacije ispitana je mogućnost proizvodnje<br />fermentisanog mlečnog napitka uz primenu različitih vrsta i koncentracija<br />nekonvencionalnog startera čajne gljive: a) nativnog inokuluma-I<br />(10% i 15%) b) koncentrovanog mikrofiltracijom - MFI (10% i 15%) i c)<br />koncentrovanog uparavanjem - UPI (1,5%, 3,0%, 10% i 15%). Varijante<br />fermentisanog mlečnog napitka dobijene su kori&scaron;ćenjem mleka sa 0,9%<br />i 2,2% mlečne masti. Za pobolj&scaron;anje fizičko-hemijskih i teksturalnih<br />karakteristika proizvoda u mleko pre inokulacije dodato je 0,02% enzima<br />transglutaminaze (aktiviran na 40&deg;C, a posle 2 sata je inaktiviran na<br />80&deg;C, 1 minut). Fermentacija mleka (pri temperaturi 42&deg;C) uz kori&scaron;ćenje<br />inokuluma čajne gljive praćena je do postizanja pH vrednosti 4,5.<br />Nakon proizvodnje analizirana je nutritivna vrednost fermentisanih<br />mlečnih napitaka: sadržaj masti, proteina, laktoze, galaktoze, glukoze,<br />fruktoze, mlečne i sirćetne kiseline, etanola, vitamina (B1, B2, B6 i<br />C), minerala (Ca, Mg, K, Na, Pb, Cd, Cu, Zn) i masnih kiselina. Sadržaj<br />odabranih komponenata u napicima praćen je tokom 10 dana skladi&scaron;tenja.<br />Fizičko-hemijske osobine (kiselost, sinerezis i sposobnost vezivanja<br />vode), teksturalne karakteristike (čvrstoća, konzistencija, kohezivnost i<br />indeks viskoziteta) i viskozitet uzoraka praćeni su nakon proizvodnje i<br />posle 10 dana skladi&scaron;tenja. Ukupan broj bakterija sirćetne kiseline (BSK)<br />i kvasaca u fermentisanim napicima analiziran je nakon proizvodnje i<br />tokom skladi&scaron;tenja. Varijante fermentisanih mlečnih napitaka senzorno<br />su ocenjene nakon proizvodnje.<br />Na osnovu rezultata ispitivanja utvrđeno je da fermentacija mleka<br />uz primenu nekonvencionalnog startera čajne gljive predstavlja složen<br />biohemijski proces pri čemu fermentacija traje od 9 do 12 sati i prosečno<br />je dva puta duža od fermentacije mleka u proizvodnji probiotskog i<br />tradicionalnog jogurta. Sadržaj laktoze tokom fermentacije mleka manji<br />je prosečno za 19,6% u odnosu na sadržaj laktoze u mleku. Uzorci<br />proizvedeni sa nativnim inokulumom uz primenu transglutaminaze i<br />koncentrata proteina surutke imaju za 15% niži sadržaj laktoze, a uzorak<br />15% I za 2% niži sadržaj u odnosu na uzorak 10% I. Uzorci proizvedeni<br />sa 10% MFI i 15% MFI imaju za 11%, odnosno 21% niži sadržaj laktoze<br />nakon proizvodnje u poređenju sa odgovarajućim uzorcima proizvedenim<br />uz primenu nativnog inokuluma. Sniženje sadržaja laktoze je<br />praćeno povećanjem sadržaja galaktoze i L-mlečne kiseline u svim uzorcima.<br />D-mlečna kiselina, sirćetna kiselina i etanol zastupljeni su u veoma<br />malim koncentracijama.<br />Imajući u vidu značaj vitamina C u ishrani i količinu detektovanu<br />u fermentisanom mlečnom napitku, konzumiranjem 500 g napitka<br />dobijenog primenom čajne gljive mogu da se zadovolje dnevne potrebe<br />za vitaminom C.<br />Tokom proizvodnje fermentisanih napitaka sadržaj vitamina B1<br />poraste za 5,09%, vitamina B2 za 2,65% i B6 za 2,03% u odnosu na<br />mleko. U fermentisanom mlečnom napitku iz mleka sa 2,2% masti<br />sadržaj vitamina B6 je povećan 24,76% u odnosu na sadržaj u polaznom<br />mleku. Fermentisani mlečni napici proizvedeni primenom čajne<br />gljive iz mleka sa 0,9% i 2,2% masti sa dodatkom 10% inokuluma<br />čajne gljive sadrže najvi&scaron;e vitamina B2 koji iznosi 108 (&mu;g/100g), odnosno<br />136 (&mu;g/100g). Mikrobiolo&scaron;ki sastav napitaka se razlikuje u zavisnosti<br />od vrste i sastava kori&scaron;ćenog inokuluma. Najveći broj BSK<br />(4,5 &middot; 104ćelija/mL) i kvasaca (9 &middot; 104 ćelija/mL) je u uzorku 10% MFI,<br />dok je manji u napitku 10% I (BSK: kvasci= 4,05 &middot; 104: 4,5 &middot; 104).<br />Dodatkom transglutaminaze u minimalnoj koncentraciji od<br />0,02% postižu se znatno bolje fizičko-hemijske i reolo&scaron;ke karakteristike<br />fermentisanih mlečnih napitaka dobijenih iz mleka sa 0,9% masti.<br />Generalno posmatrano, kori&scaron;ćenjem 10% nativnog inokuluma za<br />proizvodnju napitaka iz mleka sa 0,9% i 2,2% masti dobijaju se proizvodi<br />optimalnih hemijskih, mikrobiolo&scaron;kih i senzornih karakteristika.<br />Funkcionalni fermentisani mlečni napici proizvedeni uz primenu različitih<br />vrsta i koncentracija čajne gljive su proizvodi visoke nutritivne<br />vrednosti namenjeni različitim kategorijama potro&scaron;ača.</p> / <p> The possibility of fermented milk beverages manufacture<br /> by applying non-convenctional starter culture - tea fungus<br /> inoculum: a) natural inoculum (10% and 15%); b) concentrated<br /> by microfiltration (10% i 15%); c) concentrated by evaporation<br /> (1.5% and 3.0%) have been investigated. All fermented milk samples<br /> were produced from milk of 0.9% and 2.2 % fat content.<br /> Improvement of rheological properties of low fat fermented milk<br /> products by addition of enzyme transglutaminase (TG) was<br /> achieved. Transglutaminase (Activa MP, Ajinomoto Co. Inc.,<br /> Hamburg, Germany) was activated in milk at 40&deg;C for 2 hours,<br /> then it was inactivated by high temperature (80&deg;C for 1 minute)<br /> prior to fermentation. After cooling to optimal temperature<br /> (42&deg;C), chosen starter culture was added in milk. In all cases<br /> fermentation stopped when the pH=4.5 was reached.<br /> Nutritive characteristics of samples: content of proteins,<br /> lactose, galactose, glucose, fructose, lactic and acetic acid, ethanol,<br /> vitamins (B1, B2, B6 and C), minerals (Ca, Mg, K, Na, Pb,<br /> Cd, Cu, Zn) and total fatty acids content were analysed after<br /> production. Selected components were determined after 10 days<br /> of storage. Physico-chemical characteristics (acidity, syneresis,<br /> water-holding capacity), textural characteristics (firmness,<br /> consistency, cohessivnes, and index of viscosity) and viscosity<br /> were measured at 5&deg;C after production and during 10 days of<br /> storage.<br /> On the basis of the obtained results it can be concluded<br /> that milk fermentation lasted from 9 to 12 hours and is two times<br /> longer compared to fermentation during probiotic and traditional<br /> yoghurt production. Lactose content decreased during fermentation<br /> for 19.6% compared to milk. Higher transformation of lactose<br /> was determined in samples produced by using microfiltration<br /> inoculum. Decreasing of lactose content affected the increased<br /> galactose and L-lactic acid content. Content of D-lactic acid,<br /> acetic acid and ethanol were detected in low concentrations. High<br /> concentration of ascorbic acid in beverage contributed that 500 g<br /> fermented milk beverage could fullfill recommended daily intake<br /> for vitamin C. Sample produced from milk of 2.2% fat content<br /> using 10% natural inoculum contained the highest concentration<br /> of vitamin B2 &ndash; 136 (&mu;g/100g).<br /> The highest total cell count of acetic acid bacteria was<br /> 4.5 &middot; 104 cfu/ml and yeasts 9 &middot; 104 cfu/ml in samples produced by<br /> using 10% microfiltrated inoculum. Sample produced from milk<br /> of 0.9% fat content by applying 10% natural inoculum had also<br /> high number of acetic acid bacteria and yeasts in ratio 4.05 &middot; 104 :<br /> 4.5 &middot; 104.<br /> The sample having tea fungus concentrated inoculum<br /> and transglutaminase had the best textural characteristics. Fermented<br /> dairy beverages produced by 0.02% TG application had<br /> much better textural characteristics than those without TG.<br /> Generaly, fermented dairy drinks produced from milk of<br /> 0.9 and 2.2% fat content with addition of natural inoculum in<br /> concentration of 10% showed optimal sensory, nutritive and rheological<br /> characteristics.<br /> Therefore, fermented dairy drinks produced with tea<br /> fungus inoculum could be classified as high valuable functional<br /> food intended for all consumer categories.</p>
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Valorisation de chars issus de pyrogazéification de biomasse pour la purification de syngas : lien entre propriétés physico-chimiques, procédé de fonctionnalisation et efficacité du traitement / Valorization of chars from biomass pyrogasification for syngas purification : relationship between physico-chemical properties, functionalization process and purification efficiency

Hervy, Maxime 22 November 2016 (has links)
La pyrogazéification est un procédé de conversion thermochimique prometteur pour la valorisation énergétique des biomasses et des déchets. Ce procédé conduit à la production d’un vecteur énergétique gazeux appelé « syngas » composé principalement de CO et d’H2 mais contenant également de nombreux polluants issus des déchets entrants et/ou générés au cours de la conversion. En fonction de sa pureté, le syngas peut être valorisé dans de nombreuses applications. Cependant, la formation simultanée de résidus solides (chars) sans voie de valorisation, ainsi que le coût élevé de l'étape de purification du syngas freinent le développement industriel de cette filière. Cette thèse s'intéresse à ces deux problématiques en étudiant la valorisation des chars de pyrolyse, avec ou sans adjonction de fonctions chimiques, comme adsorbants et catalyseurs pour la purification du syngas. Dans cette étude, les chars ont été produits par pyrolyse de déchets générés sur des navires de croisière et générés en quantités importantes par les sociétés modernes : Bois de Palettes Usagées, Boues de Coagulation-Floculation et Déchets Alimentaires. Une séquence de caractérisations multi-échelle a été mise en place afin de relier les caractéristiques physico-chimiques des chars aux conditions de production ainsi qu’à la nature des déchets entrants. Les chars résultants du mélange BF/DA montrent une composition chimique riche en espèces minérales tandis que les chars produits à partir de BPU sont des matériaux très majoritairement composés de carbone. L’activation à la vapeur ne modifie pas significativement la composition des chars, mais permet de développer efficacement leur porosité. L’étude s’est ensuite intéressée aux relations existant entre les propriétés physico-chimiques des chars et leur efficacité épuratoire. La capacité d’épuration d’H2S des matériaux s’est trouvée significativement améliorée par des surfaces spécifiques élevées, de hautes teneurs en espèces minérales et un pH de surface basique. Les propriétés les plus influentes pour l’activité catalytique des chars pour le craquage des goudrons (l’éthylbenzène et le benzène sont pris comme références) en gaz légers sont : la présence d’espèces minérales, la porosité et la présence de structures carbonées désordonnées dans la matrice du char. / The pyrogasification is a thermochemical process that consists in converting biomass and/or waste into a gaseous energy carrier named syngas. This syngas is mainly composed of H2 and CO but also contains many pollutants (such as tars, H2S, HCl, particles…) that must be removed before further utilization of the syngas (electricity and heat production, synthesis of biofuel or chemicals…). The production of solid residues (chars) and the cost of the syngas purification process jeopardize the industrial development of this process. This thesis aims at studying the in-situ valorisation of the pyrolysis chars, functionalized or not, as sorbent or catalyst for the syngas cleaning. In this study, pyrolysis chars have been produced by the pyrolysis of wastes generated on cruise-ships: Used Wood Pallets (UWP), Coagulation-Flocculation Sludge (CFS) and Food Waste (FW). A set of multi-scale characterizations has been performed in order to identify relationships between the physico-chemical properties of the chars, the production conditions and the nature of the initial biomass. Chars from the mixture of FW/CFS have high mineral contents while chars from UWP are mainly carbonaceous materials. The steam activation only slightly modifies the chemical composition of the chars but significantly increases their porosity. Then, the study focused on the relationships between the physico-chemical properties of the chars and their purification efficiency. The H2S sorption capacity was strongly improved by high surface areas, large mineral contents and alkaline pH surfaces. The most important properties for the catalytic activity of the chars for tar cracking reactions were: high mineral contents, large surface areas and the presence of disorganized carbon structures in the char.

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