Catalyst deactivation in single catalyst pellets and in an isothermal catalytic fixed bed reactor have been analytically studied. The work reported here is unlike the vast majority of previous theoretical analyses which are numerical. This thesis deals with two types of deactivation - parallel and series mechanisms in which respectively, reactant and product are directly responsible for poisoning. For the single particle studies, the principal analytical tools used are based on singular perturbation theory. Use of these techniques in the temporal domain depends crucially on the smallness of the ratio of the deactivation rate constant to that of the main reaction. Depending on the range of Thiele modulus, whether small, intermediate or large, three different techniques are used in the spatial domain. First, when the Thiele modulus is small, a lumping technique due to Frank-Kamentskii (1955) is used to replace the Laplacian operator by a suitable constant. This reduces the coupled partial differential equations to ordinary ones. Main chemical kinetics of n-th order and of Michaelis-Menten type are investigated. Second, when the Thiele modulus is very large, matched asymptotic expansions in the spatial domain are used. The analysis is based on the smallness of the inverse Thiele modulus, 1/phi2. A moving reaction zone of thickness 0(1/phi) is found to separate the dead shell from the active core of the catalyst pellet. The catalyst activity profile exhibits a sharp change within the reaction zone and the structure of this profile is found to be self-preserving during the period of its propagation. Solutions are obtained for three different geometries - planar, cylindrical and spherical. The large Thiele modulus results obtained here are found to be more accurate than the shell-model solutions of Masamune and Smith (1966) (except for a slab geometry, when they are identical). Finally, for an intermediate range of Thiele modulus, finite Sturm-Liouville integral transforms along with the concept of an effective average are successfully applied. The approach taken is novel, and although not rigorously justifiable, it leads to results of suprising accuracy. The versatility of the technique is demonstrated by application to various non-linear problems which posess exact solutions and remarkable agreement is found. The finite-cylindrical catalyst pellet is also investigated using a double-integral transform in the spatial domain and it is shown that for small Thiele modulus, the infinite cylinder and slab results are good approximations to finite length cylinders with small and large ratio, R/L, respectively. The analytical solutions reported in this thesis agree well with the known numerical results of others (Masamune and Smith, 1966; Khang and Levenspiel, 1973 and Lamba and Dudukovic, 1978). The parametric - dependence of these solutions is explicit and numerical results can be easily obtained from them by hand calculation. All the single pellet results are brought together in the final chapter and used to analyze the performance of isothermal fixed-bed reactors undergoing poisoning. Such effects as external mass transfer resistance, pellet shape and chemical kinetic type are included in the analysis, which embraces the entire range of Thiele modulus.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2007. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 6 uppsatser.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 78-86). Also available on the World Wide Web.

Dissertation (D.P.H.)--University of Michigan.

Dissertation (D.P.H.)--University of Michigan.

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Made available in DSpace on 2014-06-11T19:28:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-09-21Bitstream added on 2014-06-13T18:35:18Z : No. of bitstreams: 1 dascanio_d_me_bauru.pdf: 540186 bytes, checksum: c3dd2c0d9467bd15fa5a8e18bcac9e4c (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A intoxicação por chumbo é prejudicial ao desenvolvimento das crianças, sendo potencializada por outras variáveis ambientais e sociais como: alimentação inadequada, pobreza, baixa renda e qualidade da estimulação e interação fornecidas pelos pais e escola. Isso posto, o presente estudo tem por objetivo geral comparar o desempenho intelectual de crianças com alta e baixa plumbemia com os estilos parentais nas respectivas interações com os filhos. Para isso, foi utilizada a Escala Wechsler de Inteligência - WISC-III; Roteiro de Anammese e o IEP (Inventário de Estilos Parentais). Este estudo foi realizado com 80 participantes - 40 crianças, de ambos os sexos, com idades entre 7 e 13 anos; e 40 pais (pai e mãe), todos moradores da área de risco próximo ao local de contaminação. As crianças foram divididas em dois grupos: G1 - 20 crianças com alta plumbemia (superior a 10μg/dl); e G2 - 20 crianças com baixa plumbemia (inferior a 10μ/dl). Com as informações coletadas, procedeu-se a análise estatística com Teste do Mann Whitney, com 5% de significância. Os resultados foram apresentados de forma a contemplar cinco conjuntos de dados: I) Caracterização das crianças com alta plumbemia; II) Dados anamnésicos; III) WISC-III; IV) IEP - Inventário de Estilos Parentais e V) Comparação entre o WISC-III com o IEP. A análise dos dados apontou redução da plumbemia nas crianças entre os anos de 2002 e 2005. Para as crianças com alta plumbemia os pais relataram maior número de queixa escolar, problemas de saúde, socialização e motor, embora sem significância estatística entre os grupos. Nos itens avaliados pelo WISC-III, o desempenho do Grupo I foi menor que o do Grupo 2. Na Escala de Execução o desempenho dos dois grupos foi menor que para a escala Verbal, com diferença estatística entre os grupos em: QIE (0,001) e QIOP (0,04)... / The lead poisoning cause impairment to the children's development, being strenghten by other environmental and social variables, as inadequate feeding, poverty, low income and quality of the stimulation and interaction supplied by the parents and school. The aim of the present study is to evaluate the children's intellectual development with high and low blood lead level with the parenting styles in the respective interactions with these children. In order to accomplish this study were used - WISC-III; Anamnese's Script and IEP (Parenting Styles's Inventory), in which all of the 80 participants - 40 children, of both sexes, with ages among 7 to 13 years old, and 40 parents (father or mother), lived in the risk's area, next to the contamination place. The children were divided into two groups: G1-20 children with blood lead level above 10μg/dl; and G2 - 20 children with blood lead level lower than 10μg/dl. With the collected information, the statistical analysis was preceded with Mann Whitney's test, with 5%. The results were presented in way to contemplate five groups of data: I) the children's Characterization with plumbemia; II) Anamnese's Script Date; III) WISC-III; IV) IEP - Parenting Styles's Inventory I and V) Comparison between WISC-III IEP. The analyzed data's showed a reduction of the bllod lead level in children between 2002 and 2005. For the children blood lead level the parents related a larger number of school complaints, health problems, socialization and less motor development, although without statistical difference between the groups. In the items evaluated by WISC-III, the development of Group 1 was smaller than Group 2. In the Scale of Execution the development for both groups were lower than the Verbal Scale, with statistical difference between the groups in: QIE (0,001) and QIOP (0,04). In the Parenting Styles... (Complete abstract click electronic access below)

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-10-17T12:50:34Z No. of bitstreams: 1 POLIANA PINHEIRO DA SILVA - DISSERTAÇÃO - (PPGEQ) 2018.pdf: 2144616 bytes, checksum: 6e3ed48e5f78b19665929243895dd265 (MD5) / Made available in DSpace on 2018-10-17T12:50:34Z (GMT). No. of bitstreams: 1 POLIANA PINHEIRO DA SILVA - DISSERTAÇÃO - (PPGEQ) 2018.pdf: 2144616 bytes, checksum: 6e3ed48e5f78b19665929243895dd265 (MD5) Previous issue date: 2018-05-30 / Capes / Os resíduos gerados nas Universidades representam 1% do total de resíduo em relação à outras fontes geradoras de resíduo sólidos, porém apresentam dificuldade no tratamento devido a quantidade e diversidade de compostos presente em um único resíduo. Os resíduos são classificados de acordo com características de inflamabilidade, corrosividade, reatividade, toxicidade e patogenicidade (Classe I) ou biodegradabilidade, combustibilidade ou solubilidade em água (classe II A ou classe II B). Quando são classificados em perigosos causam danos à saúde e ao meio ambiente. Uma alternativa de tratamento é a estabilização por solidificação, que promove a incorporação dos resíduos a matrizes cimentícias. O objetivo principal deste trabalho foi realizar a avaliação do metal pesado Cromo contido nos Resíduos Sólidos de Laboratórios para possível uso em Blocos sem função estrutural. No procedimento experimental, foi adotado o planejamento no delineamento do tipo one-way com análise de regressão. A primeira etapa consistiu em determinar quanto foi liberado de cromo para o meio ambiente, a partir do teste de lixiviação; o resíduo sólido de laboratório bruto foi classificado em classe I. Para definir a melhor faixa de incorporação de resíduo foram confeccionados corpos de prova para realização de testes preliminares. Os corpos de prova foram confeccionados à base de cimento Portland pozolonico, areia fina, brita e resíduo sólido passivo do laboratório de engenharia química (RSL), os quais foram submetidos a ensaios de lixiviação para classificação dos mesmos. A partir destes foram definidas as porcentagens de 5, 20 e 35% RSL, e posteriormente realizado testes de integridade/ durabilidade e imobilização de contaminantes. Os melhores resultados de todas as análises, foram encontrados para a incorporação de 5% de resíduo sólido de laboratório. As matrizes com 5 e 20% passaram de classe I (perigosos) para classe IIB( não perigosos e inertes). A matriz com 35% foi aprovada no teste de integridade/durabilidade, mas reprovada no teste de lixiviação com 0,09mg/l de cromo total, valor 55,56% acima do limite máximo permissível. Os materiais tratados poderão ser usados na fabricação de blocos com função não estrutural após avaliação técnica do uso específico adotado na construção civil. / The residues generated in the universities represent 1% of the total waste in relation to other sources of solid waste, but they present difficulties in the treatment due to the quantity and diversity of compounds present in a single residue. Residues are classified according to flammability, corrosivity, reactivity, toxicity and pathogenicity (Class I) or biodegradability, combustibility or water solubility (Class II A or Class II B) characteristics. When classified as hazardous they cause damage to health and the environment. An alternative treatment is stabilization by solidification, which promotes the incorporation of the residues to cementitious matrices. The main objective of this work is to perform the evaluation of the heavy metal Chromium contained in the Solid Waste of Laboratories for use in Blocks without structural function. In the experimental procedure, the planning was adopted in the one-way type design with regression analysis.The first step consisted in determining how much was released from chromium to the environment, from the leaching test; the crude laboratory solid waste was classified in class I. To define the best range of residue incorporation, test specimens were prepared for preliminary tests.The test specimens were made with pozolonic Portland cement, fine sand, gravel and passive solid waste from the chemical engineering laboratory (RSL), which were submitted to leaching tests to classify them. From these, the percentages of 5, 20 and 35% RSL were defined, followed by integrity / durability tests and immobilization of contaminants.The best results of all the analyzes were found for incorporation of 5% (RSL). The matrices with 5 and 20% passed from class I to class IIB, the matrix with 35% was approved in the integrity / durability test, but failed in the leaching test with 0.09mg / l of chromium above the maximum limit.

Introduction: Hepatic stellate cells (HSC) and myofibroblasts may be relevant stromal drivers of human hepatocellular carcinoma (HCC). It was hypothesised that targeted inhibition of αv integrin-mediated TGF-β activation, by HSC or hepatocytes, may result in reduced peri-tumoural and intra-tumoural extracellular matrix formation, and reduced hepatic carcinogenesis. The role of HSC in acute liver injury is less well characterised. It was anticipated that integrin signalling on HSC and hepatocytes might also be relevant in the acute setting. The emerging technique of intravital microscopy (IVM) allows detailed, real-time investigation of the cellular processes involved in hepatocyte injury, cell death and repair. It was hypothesised that this could be coupled with mouse models of HCC and acute liver injury, to perform sequential imaging under anaesthesia. Aims: (i) To determine the effect of targeted inhibition of αv integrins on HSC and hepatocytes, during hepatocarcinogenesis, in a mouse model of HCC. (ii) To investigate the effect of targeted inhibition of αv and other integrins on HSC, hepatocytes, and liver sinusoidal endothelial cells (LSEC), during acute liver injury, in the mouse model of paracetamol-induced liver injury. (iii) To develop IVM of the liver, via an abdominal imaging window, with optimisation of surgical and imaging techniques, to allow sequential imaging of the same animal. Methods: The diethylnitrosamine (DEN)-induced mouse model of hepatocarcinogenesis was used, and PDGFRβ-Cre;αvfl/fl and Alb-Cre;αvfl/fl mice were employed to deplete αv integrins on HSC and hepatocytes respectively. Tumours were harvested at 40 weeks post-DEN. Tumour size and number was evaluated in all animals. PDGFRβ-Cre;αvfl/fl and Alb-Cre;αvfl/fl mice were used in the paracetamol model, to investigate the role of αv integrins in acute liver injury. PDGFRβ-Cre;β8fl/fl and Alb-Cre;β 8fl/fl animals were also tested in this model. The role of integrins in liver sinusoidal endothelial cells (LSEC) during paracetamol-induced liver injury was evaluated using Cdh5-Cre mice. IVM of the liver was performed by surgical implantation of an abdominal imaging window, consisting of a titanium ring and coverslip, secured in place with a purse string suture. Fluorescent reporter mice were used to identify hepatic and vascular architecture, and other label-free microscope technologies were utilised to image collagen, lipid distribution, necrotic areas and blood flow within tissues. Results: In large cohorts of PDGFRβ-Cre;αvfl/fl, Alb-Cre;αvfl/fl, and control animals, there was no difference in mean tumour size or number, at 40 weeks. Targeted inhibition of α v integrins and β 8 integrin on hepatocytes, HSC or LSEC was not protective in paracetamol-induced liver injury. IVM of the liver can be performed on animals with HCC and throughout paracetamol-induced liver injury, to obtain high quality, real-time images of multiple cell lineages and the hepatic microenvironment. Conclusions: The role of TGF-β in HCC pathogenesis is complex and context-dependent. Targeted loss of αv integrin did not result in reduction in tumour burden in this non-cirrhotic model of HCC. IVM of the liver is a powerful tool to quantify inflammatory infiltrates and assessment of vascular remodelling throughout the course of acute liver injury and regeneration, providing insights into the biological processes determining recovery.