O presente trabalho tem como objetivo investigar os processos de ascensão e queda dos clorofluorocarbonetos (CFCs) como bens de consumo, bem como o desenvolvimento da percepção de risco da comunidade química em relação a esses compostos, que culminou com sua caracterização como agentes de risco ambiental global. Para isso, foi desenvolvido um estudo de caso histórico acerca do uso dos CFCs ao longo do século XX, de solução tecnológica ideal a protagonista de uma inédita dimensão de risco químico. Além disso, foi realizada uma análise de cartas enviadas por leitores, editoriais e resenhas de livros publicadas em cinco periódicos científicos: Chemical & Engineering News, Journal of Chemical Education, Environmental Science and Technology, Nature e Science, no período compreendido entre 1975 e 1991, e de livros didáticos de Química Ambiental publicados entre 1970 e 1995 - período marcado por intenso debate sobre a possibilidade de destruição da camada de ozônio estratosférica. A escolha desses periódicos e livros buscou contemplar diferentes seções da comunidade química, de modo a se ter uma amostra representativa de diferentes formas de pensamento dentro desse amplo espectro profissional que constitui a química. Para análise dessa amostra foi escolhida a Teoria Cultural de Douglas e Wildavsky, a qual descreve quatro visões de mundo que se mostram bastante adequadas para analisar as percepções de risco, as atitudes e os argumentos envolvidos nas discussões da época. Os resultados obtidos apontam para mudanças nas percepções de risco da comunidade química, aproximando-as do Princípio da Precaução para a tomada de decisões, em um período marcado pelo desenvolvimento da Química Ambiental. / This study aims to investigate the processes of rise and fall of chlorofluorocarbons (CFCs) as consumer goods, as well as the development of risk perception regarding these compounds among the chemists community, culminating in its characterization as agents of global environmental risk. A historical case study on the trajectory of CFCs throughout the twentieth century, from ideal technological solution to protagonist of an unprecedented scale chemical risk, was developed. In addition, the study includes an analysis of letters from readers, editorials and book reviews published in five journals: Chemical & Engineering News, Journal of Chemical Education, Environmental Science and Technology, Nature and Science, in the period between 1975 and 1991, and also an analysis of Environmental Chemistry textbooks published between 1970 and 1995 - a period marked by intense debate about the possibility of destruction of the stratospheric ozone layer. The choice of these journals and books sought to include different sections of the chemistry community, in order to get a representative sample of different ways of thinking within the broad professional spectrum of chemistry. Douglas\' and Wildavsky\'s Cultural Theory was selected to analyse this sample. The theory describes four worldviews that seems rather appropriate to analyze risk perceptions, attitudes and arguments involved in the discussions of the time. Results point to changes in chemists\' risk perceptions, which brought them closer to the Precautionary Principle as a guide to decision making in a period marked by the development of Environmental Chemistry.

Submitted by Rosina Valeria Lanzellotti Mattiussi Teixeira (rosina.teixeira@unisantos.br) on 2016-10-28T17:03:53Z No. of bitstreams: 1 Vanessa Martins Sarro.pdf: 631599 bytes, checksum: c6297efd7e1a593bd52bf30fe9789f75 (MD5) / Made available in DSpace on 2016-10-28T17:03:53Z (GMT). No. of bitstreams: 1 Vanessa Martins Sarro.pdf: 631599 bytes, checksum: c6297efd7e1a593bd52bf30fe9789f75 (MD5) Previous issue date: 2016-09-05 / This research aims to address the mechanisms of global governance in the protection of the ozone layer, identifying their progress and challenges, analyzing thus the awareness of humanity as a whole in relation to environmental issues intrinsically in the stratospheric ozone protection, and reference to these mechanisms to see whether these are in fact caused achievements in the subject . For this, will be assessed the Vienna Convention and the Montreal Protocol, followed by its amendments accompanying the evolution of scientific and technical progress, searching, it is shown that after the implementation of these measures, the ozone layer could be restored through international cooperation controls on production, consumption and use of ozone-depleting substances . / A presente pesquisa tem por objetivo abordar os mecanismos da governança global na proteção da camada de ozônio, identificando seus avanços e desafios, analisando, dessa forma, a conscientização da humanidade como um todo em relação às questões ambientais de forma intrínseca na proteção do ozônio estratosférico tendo, como referência, estes mecanismos para saber se, de fato, ocasionaram conquistas na temática. Para isto, serão avaliados a Convenção de Viena e o Protocolo de Montreal, seguido por suas emendas que acompanham a evolução do progresso científico e técnico, buscando ficar demonstrado que, após a implementação destas medidas, a camada de ozônio esta sendo restaurada, através de cooperação internacional de controles sobre a produção, consumo e uso de substâncias destruidoras de ozônio.

The cooperation of developing countries is commonly assumed to be essential for the establishment of effective regimes to manage global environmental interdependence. Yet their policies and perceptions have been inadequately studied. This thesis seeks to partially fill this gap in the literature with a detailed analysis of Indian policy on global environmental issues. It examines the cases of ozone depletion, climate change, and loss of biodiversity, and discusses developments up to the 1992 Earth Summit. The study addresses four broad questions about Indian policy: the process of policy making; the character of Indian interests and preferences; the nature and evolution of India's bargaining strategy; and the outcome of international negotiations for India. It reveals a complex picture of continuity and change in Indian policy. It demonstrates the enduring importance of traditions and values such as the "poverty is the greatest polluter" orthodoxy and the concepts of sovereignty, equity and Third World solidarity. It also highlights the impact of perceptions of vulnerability in relation to the North. It argues that Indian policy did not reflect purely powermaximising goals; policy makers were sometimes uncertain about where India's interests precisely lay, and felt constrained both by economic weakness and by the recognition of the mutual interest of all states in global environmental protection. This was reflected in the moderation in India's bargaining strategy. The Indian case suggests that developing countries did not regard their cooperation in the resolution of global environmental issues purely as a bargaining chip with which to extract concessions from the North. Still less did they perceive these issues as providing an opportunity to pose a macro-challenge to the North, linking agendas across issue areas. Instead, their goals reflected perceptions of constraints and mutual interests in bargaining with the North. Their bargaining strategy thus tended to be moderate and flexible, unlike the confrontational approach of the 1970s.

Thesis (Ph. D.)--Columbia University, 1999. / Includes bibliographical references (leaves 379-391).

Thesis (Ph. D.)--University of Arizona, 1992. / Includes bibliographical references (leaves 224-241).

The Community Earth System Model (CESM) is a coupling of five different models which are combined to simulate the dynamic interactions between and within the Earth's atmosphere, ocean, land, land-ice, and sea-ice. In this work, the installation and testing of CESM on Portland State University's Cluster for Climate Change and Aerosol Research (CsAR) is described and documented, and two research applications of the model are performed. First, the improved treatment of cloud microphysics within recent versions of CESM's atmospheric module is applied to an examination of changes in shortwave cloud forcing (SWCF) and results are compared to output from older versions of the model. Second, the CESM model is applied to an examination of the effect that increased methane (CH4) concentrations have had on the catalytic destruction of stratospheric ozone (O3) by ozone depleting compounds (ODCs) such as chlorofluorocarbons (CFCs) and nitrous oxide (N2O).

No description available.

Thesis Ph.D. ((Applied Mathematics)) -- University of Limpopo, 2022 / The world is under threat from the devastating effects of the continued depletion of the Ozone layer. Increased global warming is causing catastrophic ecological damage and imbalance due to accelerated melting of glaciers, rampant runaway veld res, widespread floods and other extreme events. The delegates to the Cop26 Climate Change Summit were reminded that the continued burning of fossil fuels is releasing carbon into the atmosphere at an unprecedented pace and scale and that the world is already in trouble. Complete substitution of fossil fuels with clean energy sources is the only solution through which the world can be saved from the deleterious effects of global warming. However, total dependence on renewable energy sources can only be possible through novel technology that enables efficient energy utilization and conservation. For instance, the evolution of advanced techniques in manufacturing processes has led to the reduction in the size of various industrial and engineering designs that consume reduced amounts of energy. Efficient energy utilization in thermo-fluid flow systems can be achieved through entropy generation minimization. Entropy is a thermodynamic quantity that represents the unavailability of a system's thermal energy for conversion into mechanical work. In this study, thermodynamic analysis of reactive variable properties third-grade fluid flow in channels with varied geometries and subjected to different physical effects was investigated with the second law of thermodynamics as the area of focus. Entropy generation and inherent irreversibility analysis were the main focus of the study where the sensitivities of these quantities to the embedded parameters were numerically and graphically described and analysed. The semi-analytic Adomian decomposition method, the semi-implicit fi nite difference scheme and the spectral quasilinearisation method were employed to solve the nonlinear differential equations modelling the flow systems. The results reveal that the effects of the parameters on flow velocity, fluid temperature, entropy generation and inherent irreversibility cannot be neglected. In particular, conditions for entropy generation minimization were successfully established and documented. / University of Limpopo

O presente trabalho tem o objetivo principal de compreender os possíveis efeitos da radiação energética de um evento de Gamma-Ray Burst (GRB) sobre o meio interestelar no entorno de seu local de geração e em planetas possivelmente iluminados. Gamma-Ray Bursts foram detectados pela primeira vez nos anos 60 e rapidamente atraíram a atenção da comunidade astrofísica, uma vez que as energias emitidas apenas em poderiam alcançar 1054erg, o equivalente a massa de repouso do Sol. Não se conhecia nenhum mecanismo tão eficiente para extrair energia gravitacional para produzir tal evento. Mais tarde, a possibilidade da emissão ser colimada abaixou a energia em para 5x1050erg, mas o mecanismo central de geração ainda não foi completamente desvendado, havendo muito espaço para alternativas exóticas. Estudamos os efeitos de um GRB sobre o meio interestelar, em uma tentativa de distinguir os remanescentes do GRB do gerado por múltiplas supernovas. Usamos argumentos energéticos e sobre a possibilidade de alterações químicas e isotópicas devido a reações fotonucleares. Também trabalhamos com as implicações biológicas da iluminação de planetas por um GRB, concluindo que os efeitos de tais eventos podem afetar seriamente a biosfera de um planeta mesmo a distâncias de ~10kpc. / The present work has the main goal of understanding the possible effects of the hard gamma radiation produced during a Gamma-Ray Burst (GRB) event both on the interstellar medium surrounding the source of the burst and on planets possibly illuminated. Gamma-Ray Bursts were first detected on the 60s and quickly have attracted the attention of the astrophysical community, since the energies emitted just in could reach 1054erg, the rest mass of the Sun. No mechanism was known to be so efficient in extracting gravitational energy to produce such emission. Later on, the possibility of the emission being collimated has lowered the energy of the to 5x1051erg, but the central engine has not yet been completely understood, and there is still ample room for exotic alternatives. We have studied the effects of GRB on the ISM, in an attempt to distinguish the candidates of GRB remnants from those generated by multiple supernovae. We have used both energetic arguments and the possibility of chemical alterations due to photonuclear reactions. We have also worked on the biological implications of the illumination of planets by a GRB, concluding that the effects of such event could seriously harm the biosphere of a planet even at distances of ~10kpc.

Uma pesquisa de campo foi conduzida para verificar as condições reais de utilização de clorofluorcarbonos em sistemas de refrigeração e de condicionamento de ar. A pesquisa cobriu os setores de refrigeração de supermercados, ar condicionado de edifícios e oficinas de reparação e de manutenção de geladeiras, \"Freezers\" e condicionadores de ar compactos e automotivos. A região escolhida para a pesquisa está localizada no município de São Paulo, tendo uma superfície de 12,504 Km2. As seguintes conclusões principais resultaram deste estudo: Predomina o consumo do HCFC 22 nos usuários pesquisados; a reciclagem e a recuperação ocorrem em pequena escala na região estudada; os sistemas de condicionamento de ar automotivos são a fonte mais significativa de substâncias agressivas à camada de ozônio, nos usuários pesquisados; vazamentos ocorrem por práticas de serviço não adequadas; a utilização do CFC 11 para limpeza de circuitos reduz o ganho obtido em sistemas que empregam o HCFC 22; a manutenção preventiva mostrou ser eficaz tanto para reduzir o consumo de gás refrigerante, como para reduzir a substituição de peças e componentes; a reciclagem e a recuperação do gás refrigerante tem efeito positivo em relação à camada de ozônio, economiza recursos naturais, reduz o consumo de energia, os riscos ao meio ambiente e à saúde da comunidade em geral. Finalmente, são feitas recomendações para o estabelecimento de um programa efetivo de reciclagem e recuperação de gases refrigerantes. / A field study was performed for verifying the actual conditions of the use of chlorofluorcarbons in refrigeration and air conditioning systems. The study has covered the sectors of supermarket refrigeration, building air conditioning systems, and refrigerators freezers and compact and automobile air conditioning systems repair shops. The region chosen for this study is located in the city of Sao Paulo and it has an area of 12.504 km2. The following conclusions resulted from the study: There is a predominance of the of HCFC 22 in the systems surveyied; recycling and recuperation are used in small scale in the region of the study; in the users covered by the study, the automobile air conditioning sector is the most important source of emission of ozone depleting substances; leaks occur because of bad service practices; the use of CFC 11 for circuit cleaning decreases the the gain obtained with the use of HCFC 22; the preventive maintenance has proved to be very efficient both for reducing the consum of refrigeration gases and for reducing the consum of parts and components of the refrigeration system; recycling and recuperation of refrigeration gases have positive effects in relation to the ozone layer, it saves natural resources, and reduces the risk to the enviromnent and to the public health. Finally, recommendations are made for the establishment of an effective refrigerant conservation program.