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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.
71

Environmental consequences of foreign sector expansion Mexico's maquiladora performance throughout the 1990s /

Hernandez, Pablo. January 2003 (has links)
Thesis (Ph. D.)--University of Notre Dame, 2003. / Includes bibliographical references (leaves 179-183).
72

Two-dimensional water quality modeling and waste treatment optimization for wide, shallow rivers

Eheart, James Wayland, January 1975 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1975. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography : leaves 353-355.
73

Meat packing plant effluent as an irrigation medium

Vollbrecht, Howard Albert, January 1959 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1959. / Typescript. Abstracted in Dissertation abstracts, v. 20 (1959) no. 3, p. 824. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 102-105).
74

Microbial and geochemical processes controlling the oxidation and reduction of arsenic in soils

Masur, Deanne Christine. January 2007 (has links) (PDF)
Thesis (M.S.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: William P. Inskeep. Includes bibliographical references (leaves 86-94).
75

Essays on asymmetric information and environmental regulation through disclosure /

García, Jorge. January 1900 (has links)
Thesis (doctoral)--Göteborg University, 2007. / Includes bibliographical references.
76

Desenvolvimento inicial de leguminosa forrageira em simbiose com Rhizobium em substrato tratado com biossólido da indústria de laticínios / Initial development of forage legume in symbiosis with Rhizobium in substrate treated with biosolids of the dairy industry

Machado, Lívia Rodrigues Dias [UNESP] 07 August 2014 (has links) (PDF)
Made available in DSpace on 2015-03-03T11:52:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-08-07Bitstream added on 2015-03-03T12:06:27Z : No. of bitstreams: 1 000803235.pdf: 1000125 bytes, checksum: 251635e9a630a6bb7be7c201751358a6 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho, foi avaliado o desenvolvimento inicial da leguminosa forrageira Canavalia ensiformis em interação com microorganismos capazes de estabelecer relações simbióticas, os denominados rizóbios, em substrato tratad com biossólido oriundo de indústria de laticínios. O substrato foi constituído por turfa (23%) e Cambissolo Háplico (77%), coletado na porção superior da bacia do ribeirão Guaratinguetá-SP, área degradada com risco de erosão, que apresenta relevo acentuado e solo exposto. O experimento foi desenvolvido em casa de vegetação e dividido em dois blocos: Inoculado e Não inoculado. Cada bloco contou com 6 tratamentos de adubação, constituídos por: ausência de adubação; doses de biossólido em base seca equivalente à 25%, 50%, 75% e 100% da exigência nutricional da planta; e 100% da exigência nutricional da planta em adubação mineral. A Canavalia ensiformis não possui exigência nutricional em nitrogênio, portanto os cálculos das doses de adubação foram feitos com bae na exigência em fósforo. Avaliou-se o efeito da aplicação de biossólido no crescimento inicial da leguminosa, na nodulação e fixação do nitrogênio. Observou-se que com o aumento das doses de biossólido, as plantas não inoculadas apresentaram resposta crescente no rendimento de MSPA e MSR, enquanto as plantas inoculadas obtiveram respostas decrescentes nos mesmos parâmetros avaliados. A adição de biossólido até a dose de 1.150 mg dm-3 favoreceu o desenvolvimento da relação simbiótica entre a Canavalia ensiformis e rizóbio, porém mesmo nas doses mais elevadas, de 1.720 mg dm-3 e 2.300 mg dm-3, o nitrogênio fornecido não inibiu a nodulação e a FBN. A adubação mineral, realizada com base na exigência da Canavalia ensiformis em fósforo favoreceu o estabelecimento da simbiose rizóbio-leguminosa / In this study, the initial development of forage legume Canavalia ensiformis was evaluated in interaction with microorganisms capable of establising symbiotic relationships, called rhizobia, and substrate treated with sewage sludge from the dairy industry. The substrate consisted of peat (23%) and Cambisol (77%) collected in the upper portion of the stream Guaratinguetá-SP, degraded watershed area at risk of erosion, which features sharp relief and exposed soil. The experiment was conducted in greenhouse and divided into two blocks: Inoculated and Non-inoculated. Each block had bad six fertilization treatments, consisting of: absense of fertilization; biosolid doses equivalent to 25% dry basis, 50%, 75% and 100% of the nutritional requirements of the plant; and 100% of the nutritional requirement of the plant in mineral fertilizer. The Canavalia ensiformis has no nutritional requirements in nitrogen, so the calculations of doses of fertilizers were made based on the requirement for phosphorus the effect of sewage sludge applications on the growth of legume nodulation and nitrogen fixation was evaluated. It was observed that which increasing doses of sewage sludge, non-inoculated plants showed increased response in the MSPA and MSR yield, while decreasing responses inoculated plants had the same parameters. The addition of biosolids to the dose of 1,150 mg dm-3 favored the development of the synmbiotic relationship between rhizobia and Canavalia ensiformis, but even at the highest doses of 1.720 mg dm-3 and 2,300 mg dm-3, nitrogen supplied did not inhibit nodulation and biological nitrogen fixation. The mineral fertilizer made based on the requirement of Canavalia ensiformis phosphorus favored the establishment of rhizobia-legume symbiosis
77

Utilização de modelo de referência para a melhoria dos processos construtivos de edificações buscando a redução da geração de resíduos no setor de construções residenciais

Pasa, Carine Cristiane Machado Urbim 15 February 2012 (has links)
A indústria da construção civil gera grande volume de resíduos durante a execução de seus empreendimentos e a causa desta geração está muitas vezes relacionada à forma de execução das tarefas inerentes ao processo construtivo. Na maioria dos empreendimentos não existe formalização do processo produtivo e problemas como alterações de projeto, especificação inadequada de materiais, erros de execução e falta de planejamento contribuem para agravar o problema. O processo produtivo na construção civil se caracteriza por constante ciclo de produção de novos empreendimentos, alterações no processo durante o desenvolvimento da obra, o processo produtivo é organizado por empreendimento, pouca interação entre os membros da equipe de projeto e prazo de desenvolvimento do produto bastante variável. Nesta pesquisa utiliza-se o Modelo de Referência Trevo Fractal para mapear o processo produtivo na construção de edificações residenciais com o objetivo de se propor melhores práticas que venham a reduzir a geração de resíduos. O processo de aplicação deste modelo de referência é interativo e iterativo, a escolha do ponto de partida para sua aplicação é aleatória e depende do caso que esteja sendo analisado. A abordagem do problema foi qualitativa e empregou-se como técnica a pesquisa de campo com caráter exploratório descritivo. A coleta de dados se deu através de entrevistas com engenheiros e mestres de obras e observações em obras residenciais na cidade de Ponta Grossa. Observou-se que as duas grandes causas de geração de resíduos são os erros envolvidos nas atividades de projeto e execução dos empreendimentos. Com relação aos projetos, as principais falhas são a falta de compatibilização dos mesmos e alterações no projeto durante a execução do empreendimento. Durante a execução, a geração de resíduos está relacionada a erros durante a execução das atividades devido à falta de qualificação da mão de obra e falta de planejamento e gestão da execução do empreendimento. A aplicação do modelo apontou como melhores práticas a compatibilização de projetos, o repasse de informações e possibilidade do projeto ao cliente, a qualificação da mão de obra e o gerenciamento e planejamento adequado para a execução do empreendimento. / The construction industry produces large amount of waste during the execution of their projects and the cause of this generation is often related to the way of executing the construction processes tasks. In most businesses there is no formalization of the production process and problems such as design changes, inadequate specification of materials, execution errors and lack of planning contribute to this situation. The production process in construction is characterized by constant production cycle of new developments, changes in process during the development of the work, the production process is organized by project, little interaction between team members design and product development period quite variable. In this research it was used the Fractal Clover Reference Model to map the production process in construction of residential buildings in order to propose best practices to reduce waste generation. The application process of the reference model is an interactive and iterative process, the choice of starting point for its application is random and depends on the case which is being analyzed. The approach to the problem was qualitative and employed as a technical field research with an exploratory descriptive. Data collection was through interviews with engineers, workers and observations in residential construction in Ponta Grossa city. It was observed that the two main causes of waste generation are the errors involved in project activities and implementation of projects. Regarding to projects, the main flaws are the lack of compatibility and design changes during the execution of the project. During the task execution, the generation of waste is related to errors during the performance of activities due to worker’s lack of qualification and lack of planning and management of the implementation of the project. The application of the Fractal Clover Reference Model showed as best practices the compatibility of projects, the transfer of information and feasibility of the project to the client, the qualifications of the workforce and proper management and planning for the implementation of enterprise.
78

Utilização de modelo de referência para a melhoria dos processos construtivos de edificações buscando a redução da geração de resíduos no setor de construções residenciais

Pasa, Carine Cristiane Machado Urbim 15 February 2012 (has links)
A indústria da construção civil gera grande volume de resíduos durante a execução de seus empreendimentos e a causa desta geração está muitas vezes relacionada à forma de execução das tarefas inerentes ao processo construtivo. Na maioria dos empreendimentos não existe formalização do processo produtivo e problemas como alterações de projeto, especificação inadequada de materiais, erros de execução e falta de planejamento contribuem para agravar o problema. O processo produtivo na construção civil se caracteriza por constante ciclo de produção de novos empreendimentos, alterações no processo durante o desenvolvimento da obra, o processo produtivo é organizado por empreendimento, pouca interação entre os membros da equipe de projeto e prazo de desenvolvimento do produto bastante variável. Nesta pesquisa utiliza-se o Modelo de Referência Trevo Fractal para mapear o processo produtivo na construção de edificações residenciais com o objetivo de se propor melhores práticas que venham a reduzir a geração de resíduos. O processo de aplicação deste modelo de referência é interativo e iterativo, a escolha do ponto de partida para sua aplicação é aleatória e depende do caso que esteja sendo analisado. A abordagem do problema foi qualitativa e empregou-se como técnica a pesquisa de campo com caráter exploratório descritivo. A coleta de dados se deu através de entrevistas com engenheiros e mestres de obras e observações em obras residenciais na cidade de Ponta Grossa. Observou-se que as duas grandes causas de geração de resíduos são os erros envolvidos nas atividades de projeto e execução dos empreendimentos. Com relação aos projetos, as principais falhas são a falta de compatibilização dos mesmos e alterações no projeto durante a execução do empreendimento. Durante a execução, a geração de resíduos está relacionada a erros durante a execução das atividades devido à falta de qualificação da mão de obra e falta de planejamento e gestão da execução do empreendimento. A aplicação do modelo apontou como melhores práticas a compatibilização de projetos, o repasse de informações e possibilidade do projeto ao cliente, a qualificação da mão de obra e o gerenciamento e planejamento adequado para a execução do empreendimento. / The construction industry produces large amount of waste during the execution of their projects and the cause of this generation is often related to the way of executing the construction processes tasks. In most businesses there is no formalization of the production process and problems such as design changes, inadequate specification of materials, execution errors and lack of planning contribute to this situation. The production process in construction is characterized by constant production cycle of new developments, changes in process during the development of the work, the production process is organized by project, little interaction between team members design and product development period quite variable. In this research it was used the Fractal Clover Reference Model to map the production process in construction of residential buildings in order to propose best practices to reduce waste generation. The application process of the reference model is an interactive and iterative process, the choice of starting point for its application is random and depends on the case which is being analyzed. The approach to the problem was qualitative and employed as a technical field research with an exploratory descriptive. Data collection was through interviews with engineers, workers and observations in residential construction in Ponta Grossa city. It was observed that the two main causes of waste generation are the errors involved in project activities and implementation of projects. Regarding to projects, the main flaws are the lack of compatibility and design changes during the execution of the project. During the task execution, the generation of waste is related to errors during the performance of activities due to worker’s lack of qualification and lack of planning and management of the implementation of the project. The application of the Fractal Clover Reference Model showed as best practices the compatibility of projects, the transfer of information and feasibility of the project to the client, the qualifications of the workforce and proper management and planning for the implementation of enterprise.
79

Zinc recovery from baghouse dust generated at Ferrochrome foundries

Strobos, Johannes Gerhardus 31 October 2005 (has links)
During the production of ferrochrome in electric arc furnaces, a dust is captured in baghouse filters as a means of air pollution control. This dust contains various metals such as chromium, zinc, iron, aluminium and magnesium. Due to the presence of hexavalent chromium in the dust, which is both toxic and carcinogenic, it requires disposal at a hazardous waste disposal site, entailing high cost. The possibility exists that these costs could be reduced if metals such as zinc can be recovered from the dust through, inter alia, leaching. Experiments were performed to determine suitable conditions for the leaching of zinc from such a baghouse dust. A two step leaching procedure was followed which prevented the formation of silica gel. The most favourable conditions for zinc extraction was with a sulphuric acid concentration of 336 g/l and an acid to dust ratio of 0,56. Under these conditions zinc was selectively leached with regard to iron and aluminium. The percentage recovery for zinc was 71,2%, aluminium 1,8% and iron 0,1%. It was concluded that the second step (dilution) of leaching did not have a significant influence on the percentage extraction of metals from the dust. Consideration of the chemical treatment cost of waste streams produced led to the conclusion that zinc recovery from baghouse dust is not an economically feasible project viewed in isolation. However, compared to disposal at a hazardous waste disposal site such as Holfontein, approximately R467 054,00 per annum (based on a seven day week and baghouse dust production of 3 600 kg/day) can be saved. / Dissertation (MEng (Environmental Engineering))--University of Pretoria, 2006. / Chemical Engineering / unrestricted
80

Treatment of phthalic anhydride residue for improved handling and disposal

Van Staden, Karen 31 October 2005 (has links)
The handling and disposal of hot tarry liquid residues can be problematic in industry, in this case, a phthalic anhydride plant using naphthalene as feed stock. The residue from the plant contains an appreciable amount of phthalic anhydride which desublimates from the residue during draining, resulting in an unsafe working environment. In addition, the residue is a hot liquid that solidifies upon cooling, causing additional risks to personnel during handling and various problems associated with disposal. Research was conducted into finding a treatment method to reduce or eliminate the desublimation of phthalic anhydride from the residue and addressing the hot liquid residue, making the residue safer to handle and easy to dispose of. Laboratory experiments showed that the addition of Dicalite 4151 (a filter aid) in a concentration of 0,3 kg Dicalite 4151 per kg phthalic anhydride residue, resulted in the formation of a powdered residue. This was confirmed during plant trials where using the same concentration proved that a powdered residue could be obtained, while at the same time desublimation of the phthalic anhydride from the residue was negated by distilling the product from the residue mixture. An opportunity exists to test the use of filter aid in other residue producing industries to determine if the same results can be achieved. / Dissertation (MEng (Environmental Engineering))--University of Pretoria, 2005. / Chemical Engineering / unrestricted

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