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

Three Essays In Applied Microeconomics

Carrion-Flores, Carmen Eugenia January 2007 (has links)
This dissertation applies economic theories and econometric methods to analyze the interactions between government policies and economic agents in two important and current topics: the protection of the environment and illegal migration.Following the introduction, the second chapter studies the empirical strength of bi-directional linkages between environmental standards and performance, on the one hand, and environmental innovation, on the other. Our empirical results reveal that environmental R&D both spurs the tightening of government environmental standards and is spurred by the anticipation of such tightening, suggesting that U.S. environmental policy (at least in the context of the manufacturing industries that we study) has been responsive to innovation and effective in inducing innovation.The third chapter studies whether a voluntary reduction pollution programs can prompt firms to develop new environmental technologies that yield future emission reduction benefits. Conversely, a VRP may induce a participating firm to divert resources from environmental research to environmental monitoring and compliance activities that yield short-term benefits in reduced emissions. We find evidence that higher rates of program participation are associated with significant reductions in the number of successful environmental patent applications four to six years after the program ended.The fourth chapter examines the migration duration of Mexican immigrants in the U.S. using data from the Mexican Migration Project (MMP). In the past, temporary migrations were frequent, and often the rule rather than the exception in the case of Mexican immigrants. This pattern may be changing due to the tightening of the border between Mexico and the Unites States. Moreover, this paper examines whether migration experience, demographic characteristics, economic conditions or social networks drive the time Mexican immigrants to reside illegally in the United States. The empirical analysis shows that the migration duration increases as the U.S. expected real wage increases. Tighter U.S. migration policies have an ambiguous effect on the migration duration while longer distances decrease the hazard of return to their state of origin.In the final chapter of this dissertation, the general findings are concluded and some future avenues of research are discussed.
2

Development and practical application of unhairing method without using sulfide

Takase, Kazuya, Terashima, M., Yoshimura, K. 24 June 2019 (has links)
Content: Leather manufacturing industry uses a lot of water and chemicals, and it discharges large amounts of wastewater. The processing a large amounts of wastewater requires a huge cost. Therefore, reduction of amount of a pollution load in wastewater is a theme in many countries around the world. During the leather process, a lot of pollutants occur in the unhairing process. Some estimate that the amount of pollution generated in the unhairing process accounts for 70% of the entire leather manufacturing process. In this unhairing process, usually a large amount of sulfide is used. Sulfide is known to generate hydrogen sulfide and cause damage to the drain pipe. In Tokyo, strict criteria are set for draining sulfide to sewers. Therefore, reducing the amount of sulfide used is an important task for tanner. In addition, since sulfide has no degreasing effect, a large amount of surfactant is required in the unhairing process. However, to reduce the cost and the load of the wastewater, it is also required to reduce the amount of the surfactant used. Furthermore, in recent years, the types of usable surfactants have also been limited. Therefore, development of a method of effectively removing hair loss and degreasing without using a sulfide is urgent for the leather manufacturing industry. On the other hand, pelts are widely used as raw materials for foods such as gelatin and collagen casing, cosmetics, and pharmaceuticals. However, sulfides are not originally recognized as food additives. Therefore, some companies are concerned about using pelts as a raw material for food using sulfide in the unhairing process. Also from this point of view, it is necessary to develop an unhairing method without using sulfides. The method using sodium hydroxide has been studied for a long time. However, this method is hard in handling, and is difficult to set conditions such as concentration and temperature. That is, while successful at the experimental level, it has not been put to practical use. Therefore, we studied a method to solve the above problem using sodium hydroxide. The method developed this time can reduce the pollutant in waste water, and the amount of water used in the unhairing process to 1/10 or less of the conventional one. Moreover, since it is not influenced by water temperature, it made it possible to stably remove hair irrespective of the season. The finished leather kept sufficient strength. In addition, sodium hydroxide reacts with fat in the skin and turns it into soap, so it shows the degreasing effect and contributes to reduce the dosage of degreasing agent. Take-Away: development of unhairing method without using sulfide contributes to reduce the dosage of degreasing agent reduce the pollutant in waste water
3

Essays on Environmentally Friendly Practices

Chang, Ching-Hsing 28 July 2011 (has links)
No description available.
4

Estudo da influência dos dutos de admissão no escoamento de ar em cabeçotes de motores de ignição por compressão utilizando simulações em CFD. / Study of the influence of intake ports on the air flow through cylinder heads of CI enginers using CFD simulations.

Silva, Marcel Amaro e Andrade de Morais Souza e 17 October 2016 (has links)
O controle de emissões em veículos pesados está em foco desde a década de 90, com a criação de regulamentações nacionais e internacionais que impõe limites cada vez mais rígidos para as concentrações de poluentes emitidos por estes veículos. O desenvolvimento de novas tecnologias possui papel fundamental neste processo, buscando redução nos níveis de emissões com mínimo impacto negativo no desempenho e no consumo do veículo. Para tanto, o presente trabalho visa avaliar a influência da posição dos dutos de admissão de ar de cabeçotes de motores a combustão interna, especificamente em motores de ignição por compressão (MIC) de 4 válvulas, no escoamento de ar dentro do cilindro. O escoamento do ar e o movimento de swirl são fatores importantes para a mistura e distribuição do combustível injetado, e quando otimizados para uma queima melhor distribuída, contribuem para redução nos níveis de emissões. Procura-se investigar quais direções características dos dutos são determinantes para o escoamento e para o comportamento de swirl do motor através de simulações em fluidodinâmica computacional (Computational Fluid Dynamics - CFD) utilizando o programa CD-adapco STAR-CCM+®. Os resultados de alguns dos cenários simulados são comparados a resultados de testes experimentais realizados em bancada de medição de swirl, no âmbito de outro trabalho sendo desenvolvido no mesmo grupo de projeto. / The emissions control in heavy-duty vehicles has been in focus since the 1990\'s, with the creation of national and international regulations which impose strict limits for pollutant concentrations released by these vehicles. The development of new technologies has a fundamental role in this process, aiming the reduction of emission levels with minimum impact on the performance and fuel consumption of the vehicle. Therefore, the present study aims to evaluate the influence of the position of intake ports in cylinder heads from internal combustion engines, specifically 4-valves compression-ignition (CI) engines, in the in-cylinder air flow. The air flow and swirl motion are important factors for the mixture and distribution of injected fuel, and when optimized for a better distributed combustion, contribute for the reduction of emission levels. This study investigates the characteristic directions of ports which are determinant for the air flow and swirl behaviour of the engine through Computational Fluid Dynamics (CFD) simulations using CD-adapco software STAR-CCM+®. The results from a group of simulated cases are compared to experimental test results from another project, developed on the same project group, performed in a swirl meter test rig.
5

Estudo da influência dos dutos de admissão no escoamento de ar em cabeçotes de motores de ignição por compressão utilizando simulações em CFD. / Study of the influence of intake ports on the air flow through cylinder heads of CI enginers using CFD simulations.

Marcel Amaro e Andrade de Morais Souza e Silva 17 October 2016 (has links)
O controle de emissões em veículos pesados está em foco desde a década de 90, com a criação de regulamentações nacionais e internacionais que impõe limites cada vez mais rígidos para as concentrações de poluentes emitidos por estes veículos. O desenvolvimento de novas tecnologias possui papel fundamental neste processo, buscando redução nos níveis de emissões com mínimo impacto negativo no desempenho e no consumo do veículo. Para tanto, o presente trabalho visa avaliar a influência da posição dos dutos de admissão de ar de cabeçotes de motores a combustão interna, especificamente em motores de ignição por compressão (MIC) de 4 válvulas, no escoamento de ar dentro do cilindro. O escoamento do ar e o movimento de swirl são fatores importantes para a mistura e distribuição do combustível injetado, e quando otimizados para uma queima melhor distribuída, contribuem para redução nos níveis de emissões. Procura-se investigar quais direções características dos dutos são determinantes para o escoamento e para o comportamento de swirl do motor através de simulações em fluidodinâmica computacional (Computational Fluid Dynamics - CFD) utilizando o programa CD-adapco STAR-CCM+®. Os resultados de alguns dos cenários simulados são comparados a resultados de testes experimentais realizados em bancada de medição de swirl, no âmbito de outro trabalho sendo desenvolvido no mesmo grupo de projeto. / The emissions control in heavy-duty vehicles has been in focus since the 1990\'s, with the creation of national and international regulations which impose strict limits for pollutant concentrations released by these vehicles. The development of new technologies has a fundamental role in this process, aiming the reduction of emission levels with minimum impact on the performance and fuel consumption of the vehicle. Therefore, the present study aims to evaluate the influence of the position of intake ports in cylinder heads from internal combustion engines, specifically 4-valves compression-ignition (CI) engines, in the in-cylinder air flow. The air flow and swirl motion are important factors for the mixture and distribution of injected fuel, and when optimized for a better distributed combustion, contribute for the reduction of emission levels. This study investigates the characteristic directions of ports which are determinant for the air flow and swirl behaviour of the engine through Computational Fluid Dynamics (CFD) simulations using CD-adapco software STAR-CCM+®. The results from a group of simulated cases are compared to experimental test results from another project, developed on the same project group, performed in a swirl meter test rig.
6

Plan de Negocio: Ecomestible

Castillo Osorio, Karina Sofia, Dellepiane Espinoza, Jorge Luis, López Cavero, Stephany, Velásquez Jaramillo, Angie Sofía 01 December 2020 (has links)
El presente proyecto de investigación consiste en el desarrollo del negocio Ecomestible. Esta investigación trata de utensilios comestibles de diversos sabores y que reducen la contaminación ambiental. Este trabajo nos permite ver que tan factible será el proyecto tanto a corto, mediano y largo plazo por medio de diversas investigaciones realizadas en Lima metropolitana para la zona 7 para hombres y mujeres entre 18 a 55 años de edad del nivel socioeconómico B y C. Además, cuando se investigó el mercado se descubrió una oportunidad económica maravillosa, ya que somos los primeros en sacar este producto al mercado. Por lo cual, se pudo determinar que nuestro público objetivo desea reducir el uso del plástico, contribuir con el medio ambiente y mantener una vida saludable. Por ello, se hizo una fórmula de ingredientes naturales, sin ningún tipo de preservantes para asegurar utensilios comestibles totalmente ecológicos, orgánicos y al alcance de nuestro público objetivo. Por último, en este trabajo se realizó entrevistas, encuestas de google, publicidad pagada en redes sociales, específicamente en facebook para conseguir un mayor alcance de clientes potenciales. / This research project consists of the development of the Ecomestible business. This research deals with edible utensils of various flavors and that reduce environmental pollution. This work allows us to see how feasible the project will be both in the short, medium and long term through various investigations carried out in metropolitan Lima for zone 7 for men and women between 18 to 55 years of age of socioeconomic level B and C. In addition, when the market was investigated a wonderful economic opportunity was discovered, as we are the first to bring this product to market. Therefore, it was determined that our target audience wants to reduce the use of plastic, contribute to the environment and maintain a healthy life. For this reason, a formula of natural ingredients was made, without any type of preservatives to ensure totally ecological, organic edible utensils and within reach of our target audience. Finally, in this work, interviews, google surveys, paid advertising on social networks, specifically on Facebook, were carried out to achieve a greater reach of potential customers. / Trabajo de investigación
7

Совершенствование системы государственного мониторинга атмосферного воздуха в рамках проведения эксперимента по квотированию выбросов загрязняющих веществ на примере ГО Нижний Тагил : магистерская диссертация / Improving the system of state monitoring of atmospheric air as part of an experiment on the allocation of pollutant emissions by the example of Nizhny Tagil

Дятлова, А. С., Dyatlova, A. S. January 2020 (has links)
Currently, many governments are developing programs and environmental initiatives aimed at reducing the level of harmful emissions into the atmosphere through the implementation of environmental enterprises. In 2018, the Ecology National Project was adopted in Russia, with a total budget of 54 trillion rubles. Within the framework of the National Project, 12 federal projects are being implemented, one of which, the Clean Air project, is aimed at reducing the level of air pollution in large industrial centers and at improving the existing monitoring system, since the reliability of the results obtained during implementation depends on its effectiveness. federal project "Clean Air" results. / В настоящее время правительства многих стран разрабатывают программы и экологические инициативы, направленные на снижение уровня выбросов вредных веществ в атмосферу за счет реализации природоохранных предприятий. В 2018 году в России был принят к исполнению Национальный проект «Экология», общий бюджет которого составляет 54 трлн руб. В рамках Национального проекта реализуется 12 федеральный проектов, один из которых, проект «Чистый воздух», направлен на снижение уровня загрязнения атмосферного воздуха в крупных промышленных центрах и на совершенствование существующей системы мониторинга, так как именно от эффективности её деятельности зависит достоверность полученных в ходе реализации федерального проекта «Чистый воздух» результатов. Актуальность исследования определяется необходимостью разработки предложений по совершенствованию системы экологического мониторинга в ГО Нижний Тагил одного из городов-участников эксперимента по комплексному квотированию выбросов рамках Федерального проекта «Чистый воздух» и национального проекта «Экология».

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