Made available in DSpace on 2014-06-11T19:29:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-01-29Bitstream added on 2014-06-13T19:17:39Z : No. of bitstreams: 1 falleiros_mb_me_botfmvz.pdf: 753532 bytes, checksum: 09df2201bbfb5625659993b6522a5251 (MD5) / Universidade Estadual Paulista (UNESP) / Objetivou-se estudar os efeitos do extrato de lipoproteínas de baixa densidade sobre o sêmen ovino durante a refrigeração. Vinte amostras de 5 carneiros foram refrigeradas por 24 e 48 horas na geladeira para refrigeração Minitube, nos meios diluentes Glicina Gema Leite, Glicina Gema purificada Leite e Glicina Extrato Leite e submetidas a teste de exaustão (37ºC/240 minutos) sendo avaliados in vitro por meio das análises da cinética espermática computadorizada, da morfologia e da integridade da membrana plasmáticas. Após 24 e 48 horas de refrigeração, os meios Glicina Gema purificada Leite e Glicina Extrato Leite apresentaram resultados superiores ao meio Glicina Gema Leite, após o teste de exaustão, para o parâmetro de integridade de membrana plasmática. Para a integridade de acrossomo o meio Glicina Gema purificada Leite foi superior (P<0,05) em relação ao meio Glicina Gema Leite durante o teste de exaustão. Nos demais parâmetros estudados de cinética espermática e morfologia (cauda dobrada), não houveram diferenças significativas (P>0,05) entre os meios. Entre os momentos, houve diferença significativa (P<0,05) em todos os meios durante o teste de exaustão / The objective was to study the effects of extract of low density lipoproteins on ovine semen during cooling. Twenty samples of five sheep were chilled for 24 and 48 hours in the refrigerator for cooling Minitube, in extenders Glycine Yolk Milk, Glycine purified Yolk Milk and Glycine Extract Milk and tested to exhaustion (37 ° C/240 min) were evaluated in vitro by means of computerized analysis of sperm kinetics, morphology and plasma membrane integrity. After 24 and 48 hours of refrigeration, the extenders Glycine purified Yolk Milk and Glycine Extract Milk showed better results than extender Glycine Yolk Milk, after the exhaustion test, for the parameter of membrane integrity. For the integrity of the acrosome through Glycine purified Yolk Milk was higher (P <0.05) than Glycine Yolk Milk during the exhaustion test. In other parameters of sperm kinetics and morphology, there were no significant differences (P> 0.05) among extenders. Between times, significant difference (P <0.05) in all extenders during the exhaustion test

Orientador: Tomaz Manubu Hashimoto / Banca: Marcelo dos Santos Pereira / Banca: Cristina de Carvalho Ares Elisei / Resumo: Com os novos desafios impostos pelas condições cada vez mais severas dos poços de petróleo offshore a necessidade de materiais mais modernos e com melhores propriedades mecânicas tem sido um desafio constante. Neste trabalho foi realizada a caracterização mecânica de tubos fabricados a partir de chapas de aço laminadas a quente, seguido de resfriamento acelerado. Os valores reportados são resultados de testes de laboratório aplicados em corpos de prova retirados do metal de base, de solda e da zona termicamente afetada. A utilização destes aços na fabricação de tubos soldados por processo arco-submerso em dois passes, utilizando arcos múltiplos, tem apresentado resultados de tenacidades confiáveis e superiores aos obtidos a partir de chapas laminadas pelo processo de laminação controlada sem resfriamento acelerado, principalmente em espessuras de 16 mm e superiores. Os requisitos do teste de tenacidade especificados pela norma DNV-OS -F101 aplicados em tubos fabricados de acordo com a norma API 5L, são considerados críticos. A criticidade é função dos valores mínimos a serem obtidos e também da freqüência estabelecida para ser aplicada em cada corrida de aço utilizada na produção de cada item de fabricação. Com isso nota-se uma enorme vantagem do uso dos aços com o processo de resfriamento acelerado, visto que os mesmos tiveram uma melhor homogeneidade nos resultados de limite de escoamento, com um ganho significativo no alongamento e apenas uma pequena redução no limite de resistência. O fato de usarem menores teores de carbono, também favoreceu muito a tenacidade no metal de base e ao longo da ZTA, tendo diferenças extremamente significativas de ganho no teste de impacto e CTOD / Abstract: The main of this work is the mechanical properties characterization of pipes made from steel plates produced using hot rolling with accelerated cooling. The values reported are laboratory tests results, applied on samples taken from the base metal, weld and heat affected zone. The use of these steel plates in the manufacture of pipes by submerged arc welding process using multiple arcs has shown toughness and elongation results superior to those obtained by using hot rolled steel plates without accelerated cooling, particularly in thicknesses of 16 mm and higher. The toughness test requirements specified by DNV-OS-F101 applied for pipes manufactured aiming offshore application are considered critical. The criticality is function of the minimum values required set the sampling frequency to be applied in every steel heat used in the production of each product. Because of this the use of accelerated cooling process shows a significant advantage, since it provides a better homogeneity in yield strength results, with a significant gain in elongation and only a small reduction in tensile strength. The use of smaller amounts of carbon also greatly fostered toughness in base metal and along HAZ, with significant improvement in the impact test and CTOD. Results due to these enhanced properties the use of steels with accelerated cooling technology is essential in order to face technological challenges imposed by new requirements of submarines pipelines / Mestre

Orientador: Carlos Daniel Ebinuma / Banca: José Luz Silveira / Banca: José Nédilo Carrinho de Castro / Banca: Jeronimo dos Santos Travelho / Banca: Sebastião Cardoso / Resumo: O resfriamento evaporativo consiste na utilização da evaporação da água através da passagem de um fluxo de ar, provocando a redução na temperatura do ar e, apesar de utilizarem tecnologia relativamente simples, ainda são pouco utilizados para o condicionamento de ar em regiões de clima úmido. Este trabalho realiza um estudo dos potenciais e limitações de sistemas de condicionamento de ar por resfriamento evaporativo e evaporativo-adsortivo quando utilizados com o objetivo de propiciar conforto térmico ao homem e reduzir o consumo de energia. Apresenta-se, inicialmente, o princípio de funcionamento de sistemas de resfriamento evaporativo e de desumidificadores por adsorção. A seguir, apresentam-se os resultados dos ensaios de desempenho realizados em um resfriador evaporativo direto e propõe-se um novo sistema a ser utilizado em regiões em que as condições de conforto não podem ser supridas pelo resfriamento evaporativo somente. Estuda-se a aplicação desses sistemas a diversas cidades, caracterizadas por diferentes condições climáticas e conclui-se que os sistemas de resfriamento evaporativo acoplados a um desumidificador adsortivo apresentam perspectivas promissoras, principalmente para aplicação em condicionamento de ar onde existem fontes de calor de baixo custo ou calor residual disponível. A análise das condições do ar de insuflamento demonstra a viabilidade da utilização do sistema proposto para conforto térmico humano em regiões de clima úmido como uma alternativa aos sistemas convencionais de condicionamento de ar, poupando energia e protegendo o meio ambiente. / Abstract: Evaporative cooling consists in using water evaporation through the passage of an air flow, thus decreasing the air temperature. In spite of using simple technology, it is seldon used for air conditioning in humid climate regions. This thesis develops a methodology that can be used to establish potentials and limitations of air conditioning systems by evaporative and desiccant cooling when used for human thermal comfort and lower power consumption. Firstly, the operational principles of evaporative cooling and dehumidification by adsorption systems are presented. Next, the results of performance tests developed on a direct evaporative cooler are described. Finally, a new system to be used in regions where the thermal comfort conditions cannot be supplied only by evaporative cooling is proposed. The applications of this system in several cities, characterized by different climate conditions are studied. It concluded that evaporative cooling systems coupled to a dehumidification adsorption system present promising perspectives, mainly to low cost air conditioning applications where residual heat sources are available. The analysis of the supply air conditions shows the feasibility of the proposed system for human thermal comfort in humid climates as an alternative to conventional air conditioning systems, saving energy and protecting the environment. / Doutor

Made available in DSpace on 2014-06-11T19:30:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-01-04Bitstream added on 2014-06-13T18:40:00Z : No. of bitstreams: 1 tassini_jo_me_guara.pdf: 1303049 bytes, checksum: 305724b8b2b6efcf44bbdd121e531009 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Em alguns tipos de indústria, como por exemplo a de laticínios, bebidas e frigoríficos, o sistema de refrigeração é responsável por uma parcela significativa no consumo de energia elétrica. Tendo como objetivo a redução deste consumo, foi realizado um estudo de caso em uma indústria produtora de bebidas, sendo analisados todos os componentes do sistema de refrigeração. O sistema de refrigeração analisado utiliza amônia anidra (NH3) como fluido refrigerante no circuito principal e solução de etanol no circuito secundário, sendo composto por compressores do tipo parafuso, condensadores evaporativos, evaporadores de placas, conjunto de bombas e válvulas expansoras com controle eletrônico. Usualmente, os sistemas de refrigeração atendem diversos processos e etapas de produção, que diferem nos requisitos de temperatura de produto. Além disso, por serem projetados para atender a maior demanda esperada, constituem uma grande oportunidade de otimização nos períodos fora de pico de consumo. Foram descritos e detalhados os componentes do sistema de refrigeração, bem como todas as ações e requisitos necessários para melhoria na eficiência energética da instalação. A implementação destas ações de melhoria de eficiência na planta industrial estudada contou com um investimento total de R$ 302.000,00, e foram responsáveis por um ganho anual de R$ 241.000,00, correspondentes a uma redução no consumo elétrico de 1,7 GWh/ano. O payback simples, portanto, é de 1,25 anos / In some types of industry where cooling systems are required, for example, dairy products, beverages and frozen foods, the cooling system is responsible for a significant portion of electricity consumption. Aiming to reduce this consumption, a case study was performed in a beverage industry, and all the refrigeration systems components were analyzed. The cooling system operates using anhydrous ammonia (NH3) as the refrigerant in the main circuit and ethanol solution in the secondary circuit, it consists of screw compressors, evaporative condensers, plate and frame coolers, pumps and expansion valves with electronic control. Usually, refrigeration systems have several processes and production stages to meet for different products, depending on the products temperature requirements. Moreover, they are designed to attain the highest demand expected, which gives a great opportunity to optimize the off-peak periods of consumption. We have described and itemized whole refrigeration systems components, as well as all actions and requirements to improve the energy efficiency of the installation. The energy efficiency improvements actions that were implemented in this industrial plant study had a total investment of R$ 302,000.00. These improvementes resulted in an annual saving of R$ 241,000.00, as well a relative a reduction in electricity consumption of 1,7 GWh/year. Therefore, the simple payback is 1.25 years

Orientador: Vivaldo Silveira Junior / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T02:26:51Z (GMT). No. of bitstreams: 1 Afonso_MarcosRodriguesAmorim_D.pdf: 11650736 bytes, checksum: 7e5d5f2552930a2f6fab23787c54259b (MD5) Previous issue date: 2005 / Doutorado / Engenharia de Alimentos / Doutor em Engenharia de Alimentos

M.Sc. (Mechanical Engineering) / Please refer to full text to view abstract

The idea of snow cooling in this case is to save snow from winter to summer and to use it for air conditioning and for saving energy in the production of ice in hockey arenas. Today in Sweden, snow power on a large scale is used only on one place, the hospital in Sundsvall. There you’ll find a pond with 70 000 m3 of snow. The melt water in the pond is heated up while cooling down warm air from the hospital, before circulating back to the pond where it regains a low temperature passing through the snow. The idea was to examine the possibility to use such a system in Västerås, at the multiple sports arenas at Rocklunda, partly for air conditioning and partly for ice production. This work was made possible through gathering information on snow storage and on the Sundsvall snow cooling plant, by interviewing people with insight in the Sundsvall hospital and Rocklunda sports arenas and by calculating the electricity consumption, necessary amount of snow and making an LCC-analysis. For air conditioning the melt water would be used like in Sundsvall but for ice production the melt water would be used for condensing the cooling media in the heat pump at a lower temperature then it would do while cooling with air or river water during summer. Annual electricity savings of 120 and 154 MWh for the arenas were made for 2016 and 2017 when using the snow for ice production. For the air conditioning the saving were estimated to around 55 MWh per year. A snow dispatch hatch in one of the hockey arenas made an alternative to a full-scale snow cooling system. Using this hatch for temporal snow power could save up to 62 MWh per year when used for ice production and 38 MWh when used for air conditioning. The estimated costs for construction of said system proved to be too expensive for making a full-scale snow power system a reality. For ice production a storage of 103 000 m3 of snow was needed which made for a result of -57 MSEK in the LCC-analysis. For the air conditioning alone, a storage of 6 000 m3 was needed which made for a result of -4.2 MSEK. The snow dispose hatch, even without the need of snow storage, resulted in -5.9 MSEK for ice production and -1.6 MSEK for air conditioning. With more thoroughly estimations of the investment costs, together with global warming and thus bigger potential for saving energy, this might be a promising investment in the future.

University of Macau / Faculty of Science and Technology / Department of Electromechanical Engineering

A mathematical model which predicts the cooling system performance for a rally car is derived in this study. A case study vehicle was made available by a local manufacturer for evaluation of the cooling system. Two heat exchangers compatible for the vehicle were tested in a controlled wind tunnel environment to determine its heat transfer characteristics. Including the relationship between fluid flows and vehicle speed, a function resulted through which the cooling system performance can be predicted. Including the heat generated by the engine to be dissipated by the cooling system and the effect of ambient conditions on heat generated and dissipated, an energy balance results. Using the energy balance a contour plot is generated which predicts the suitability of the heat exchanger at various ambient conditions. The tool thus allows the user to assess the cooling system on the day of the race, highlighting whether the required cooling will be achieved. / Dissertation (MEng(Mechanical))--University of Pretoria, 2007. / Mechanical and Aeronautical Engineering / unrestricted

The successful industrial applications of pinch analysis techniques in energy optimisation and wastewater minimisation have resulted in the recent studies of combined mass and heat integration. Kim and Smith (2001) have demonstrated that operation of cooling water networks in series, rather than the conventional parallel arrangement improve cooling tower and cooling water network performance in new and retrofit design. In this work, utilising a superstructure to determine the mathematical formulation that characterises a cooling water network supplied by multiple cooling water sources, which often occurs in practice, extends this methodology. It is further demonstrated that the optimum cooling water supply to a network of cooling-water-using operations supplied by multiple sources is determined by considering the entire framework of sources and cooling-water-using operations, that is, unified targeting. This optimum is better than that obtained from considering individual subsets of cooling-water-using operations and its respective source, that is, single source targeting. Relevant practical constraints were included in the formulations to enhance robustness and applicability to real life situations. Practical constraints consisted of maximum return temperatures to cooling water sources, as wells as dedicated water sources and sinks of cooling-water-using operations. This concept was applied to an illustrative example and a case study of the Sasol Synfuels (Pty) Limited cooling water system that consisted of individual networks supplied by separate water sources. For the case with maximum water reuse the single source targeting method yielded an improvement of 11.6% over the parallel target for the illustrative example. In comparison, superior results were obtained with the developed unified targeting method, which yielded an improvement of 18.4%. Likewise, for the case with the aforementioned practical constraints 6.8% and 7.6% improvements were forecasted for the single source and unified targeting methods respectively. For the maximum reuse scenario of the case study, improvements of 37.9% and 41.0% over the parallel target were obtained using the single source and unified targeting methods, respectively. Similarly, considering practical constraints improvements of 20.3% and 31.1% were obtained. In both the illustrative example and case study the unified targeting method resulted in superior results than the single source targeting methods. / Dissertation (MEng (Chemical Engineering))--University of Pretoria, 2008. / Chemical Engineering / unrestricted