697 resultados para Elicottero raffreddamento ejector exhaust
Resumo:
Há mais de 30 anos o Brasil tem desenvolvido políticas específicas para o setor de informática, desde a Política Nacional de Informática da década de 70, passando pelo Período de Reserva de Mercado dos anos 80 e, nos dias de hoje, em que as Tecnologias de Informação e Comunicação (TIC) são tidas como uma das áreas prioritárias na Política Industrial. Dentre as metas atuais, destaca-se o foco na ampliação do volume de exportações de software e serviços. Contudo, apesar dessas pretensões, o país não tem tido destaque internacional expressivo para o setor. Por outro lado, a Índia, também considerada como um país emergente, figurando na lista dos BRIC, foi responsável pela exportação de cerca de US$47 bilhões em software e serviços de Tecnologia da Informação (TI) em 2009, se destacando como um país protagonista no mercado internacional do setor. A implementação de uma indústria tecnicamente sofisticada como a do software, que exige um ambiente propício à inovação, em um país em desenvolvimento como a Índia chama a atenção. De certo existiram arranjos jurídico-institucionais que foram utilizados naquele país. Quais? Em que medida tais arranjos ajudaram no desenvolvimento indiano do setor? E no Brasil? Este trabalho parte da hipótese de que o ambiente jurídico-institucional desses países definiu fluxos de conhecimento distintos, influenciando o tipo de desenvolvimento do setor de software de cada um. Averiguar como, entre outros fatores sócio-econômicos, esses arranjos jurídico-institucionais influenciaram na conformação diversa de fluxos de conhecimento é o objetivo específico desta pesquisa. Entende-se aqui como ambiente jurídico-institucional todas as regulamentações que estabelecem instituições, diretrizes e condições comuns para determinado tema. Partindo do pressuposto de que o setor de software desenvolve atividades intensivas em conhecimento, para cada país em questão, serão analisados apenas arranjos jurídico-institucionais que tiveram, ou têm, poder de delimitar o fluxo de conhecimento referente ao setor, sejam eles provenientes de políticas comerciais (de exportação e importação, ou de propriedade intelectual) ou de políticas de investimento para inovação. A questão fundamental ultrapassa o debate se o Estado deve ou não intervir, para focar-se na análise sobre os diferentes tipos de envolvimento observados e quais os seus efeitos. Para tal, além de revisão bibliográfica, foi feita uma pesquisa de campo na Índia (Delhi, Mumbai, Bangalore) e no Brasil (São Paulo, Brasília e Rio de Janeiro), onde foram conduzidas entrevistas com empresas e associações de software, gestores públicos e acadêmicos que estudam o setor.
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Este trabalho originou-se de uma preocupaçao maior de contribuir, com algo realmente significativo, para a Universidade Federal do Maranhão. Para tantô, estabelecemos parâmetros, que nos fornecessem subsídios na elaboração do objeto proposto. Inicialmente, procuramos definir uma postura teórica metodológica que melhor se adaptasse, na compreensão dos interesses de uma classe hegemônica. No segundo capítulo fizemos uma retrospectiva histórica dos acontecimentos que marcaram o Ensino Superior no Brasil, com o cuidado de deixar bem claro o predomínio de uma classe dominante, interferindo na constituição da Universidade brasileira. Não temos a pretensão de esgotar todas as variáveis que atingiram direta ou ind1retamente o ensino, mas acreditamos fornecer alguns elementos que, no futuro, servirão de base para uma maior reflexão em torno de problemas tão significativos. No terceiro capítulo, procuramos analisar a Política Edu cacional Brasileira, selecionando alguns tópicos por considerarmos mais adaptados ao nosso estudo. Esta escolha foi bastante criterio sa, pelo volume de publicação existente, aliada a um conteúdo subs tancioso. No quarto capítulo, haja vista o nosso objetivo, utiliza mos, também, como parâmetro, a política Nacional de Saúde, direcio nada como tem sido até hoje, a atender uma população que a fortale ça como classe dominante, ao mesmo tempo, selecionando mecanismos _falaciosos para a manutenção do seu mercado de trabalho. No quinto capítulo, procuramos reconstruir o surgimento dos Cursos da Área de Saúde, da Universidade do Maranhão, tomando como pano de fundo as contradições de uma instituição que busca en contrar sua identidade, mas é limitada, a nível Nacional, a uma Po lítica de Educação e Saúde e, a nível regional, a disputa pela hegemonia, tendo em vista os interesses de grupos e não de uma socie dade • Na última parte, a título de conclusão, procuramos responder as questões por nós levantadas no primeiro capítulo, após a análise de todo conteúdo desenvolvido.Não nos esquecemos, também, de caracterizar, em cada capítulo, as condições do contexto sócio-político-econômico do País, em cada período analisado, proporcionando-nos uma visão dialética dos acontecimentos em pauta .
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I study optima in a random-matching model of outside money. The examples in this paper show a conflict between private and collective interests. While the planner worry about the extensive and intensive margin effects of trades in a steady state, people want the exhaust the gains from trades immediately, i.e., once in a meeting, consumers prefer spend more for a better output than take the risk of saving money and wait for good meetings in the future. Thus, the conflict can force the planner to choose allocations with a more disperse money distribution, mainly if people are im- patient. When the patient rate is low enough, the planner uses a expansionary policy to generate a better distribution of money for future trades.
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Apesar de sua complementariedade, as práticas de planejamento estratégico e de busca pela qualidade do serviço e da gestão pública tem recebido ênfase alternada ao longo da história política brasileira, acompanhando percepções acerca do papel do Estado. Na administração municipal adquirem especial relevância e complexidade dado histórico de expansão urbana pouco planejada, grande concentração populacional nessas áreas e necessidade de integração de uma série de instrumentos e diretrizes propostos pela Constituição de 1988 e pelo Estatuto da Cidade. O presente trabalho visa sistematizar o histórico desses debates no Brasil, sem pretensão de aprofundamento, e apresentar breves contribuições sobre a situação atual do planejamento e gestão nos municípios.
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Efforts in research and development of new technologies to reduce emission levels of pollutant gases in the atmosphere has intensified in the last decades. In this context, it can be highlighted the modern systems of electronic engine management, new automotive catalysts and the use of renewable fuels which contributes to reduce the environmental impact. The purpose of this study was a comparative analysis of gas emissions from a automotive vehicle, operating with different fuels: natural gas, AEHC or gasoline. To execute the experimental tests, a flex vehicle was installed on a chassis dynamometer equipped with a gas analyzer and other complementary accessories according to the standard guidelines of emission and security procedures. Tests were performed according to NBR 6601 and NBR 7024, which define the urban and road driving cycle, respectively. Besides the analysis of exhaust gases in the discharge tube, before and after the catalyst, using the suction probe of the gas analyzer to simulate the vehicle in urban and road traffic, were performed tests of fuel characterization. Final results were conclusive in indicating leaded gasoline as the fuel which most contributed with pollutant emissions in atmosphere and the usual gasoline being the fuel which less contributed with pollutant emissions in atmosphere
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This research work deals with the compilation of a dictionary on clothing terminology intended to be used as a pedagogic tool as part of the teaching and learning process in the Textile Engineering Course at the Federal University of Rio Grande do Norte. The main terms were selected and assessed by a team of textile teachers and students with the objective to be structured as a conceptual body of information on the following sub-areas of clothing terminology: materials (fabrics and trimmings) and products (garments). This research comprises three main steps: (a) characterization and understanding of the technical vocabulary in the clothing area as well as the identification of a pedagogic demand for a dictionary on clothing terminology, clearly expressed by the textile lecturers and students involved in the assessment of the need and validation of this project development; (b) a proposal for a specific methodology for the compilation of the dictionary which could help the communication process in the lecturing of clothing terminology and (c) based on the terminological principles and the technique of focal groups the dictionary was assessed. The technique of focal groups was used in the first step. In the second step the technique used was that of the terminological methodology adapted to the teaching approach in the Textile Course. In the third step the technique of focal groups was again utilized. It was observed that the main concern of lecturers and students is the lack of a standardized vocabulary, which renders difficult the communication process in both the teaching and learning activities as well as the professional ones in the textile industries. Various aspects, which can overlap, cause this lack of standardization. The main ones pointed out by the study team in the focal groups are: usage of regional words or expressions, usage of foreign words or expressions, analogies, and the low level of formal education, mainly among the industry workers. Another aspect to be considered is the lack of textile literature written in the Portuguese language of Brazil. This evidence shows the importance of a clothing terminology dictionary which will benefit both the education and professional activties in this field of knowledge. This dictionary will also give a substantial contribution to terminological standardization in our research field. With view to fulfill this demand, a dictionary of clothing terminology was compiled with 760 main entries, according to the modern practice in terminology with the necessary modifications concerning our needs. The result of the dictionary assessment was very assertive regarding its structure, contents and possible use in various contexts. The team work emphasized their contribution to the standardization process of the terms that proved to be one of the most important and difficult aspects of this researh work. The significance of this structured terminological dictionary was confirmed by the focal group participants relating to its use for teaching and learning activities, as a reference book, as a source of technical information and also as a tool for pedagogic studies and planning, as well as a significant collaboration to the pedagogic practices in the textile engineering course at University or any other educational institution. Besides, this dictionary can also be used to supply information within the textile field. We are aware that the present work will not exhaust the objectives of this research due to its limitations in opposition to the vast complexity demanded by the compilation of a complete work including all the areas and sub-areas of textile engineering. However, it is an important source for dissemination of concepts on the field of clothing terminology and a tool to effective standardization of the terms used in this subject field
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Caffeine is the legal stimulant consumed most extensively by the human world population and may be found eventually in the urine and/or blood of race horses, the fact that caffeine is in foods led us to determine the highest no-effect dose (HNED) of caffeine on the spontaneous locomotor activity of horses and then to quantify this substance in urine until it disappeared. We built two behavioural stalls equipped with juxtaposed photoelectric sensors that emit infrared beams that divide the stall into nine sectors in a 'tic-tac-toe' fashion. Each time a beam was interrupted by a leg of the horse, a pulse was generated; the pulses were counted at 5-min intervals and stored by a microcomputer. Environmental effects were minimized by installing exhaust fans producing white noise that obscured outside sounds. One-way observation windows prevented the animals from seeing outside. The sensors were turned on 45 min before drug administration (saline control or caffeine), the animals were observed for up to 8 h after i.v. administration of 2.0, 2.5, 3.0 or 5.0 mg caffeine kg(-1). The HNED of caffeine for stimulation of the spontaneous locomotor activity of horses was 2.0 mg kg(-1). The quantification of caffeine in urine and plasma samples was done by gradient HPLC with UV detection. The no-effect threshold should not be greater than 2.0 mug caffeine ml(-1) plasma or 5.0 mug caffeine ml(-1) urine. Copyright (C) 2001 John Wiley & Sons, Ltd.
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The vehicles are the main mobile sources of carbon monoxide (CO) and unburned hydrocarbons (HC) released into the atmosphere. In the last years the increment of the fleet of vehicles in the municipal district of Natal-RN it is contributing to the increase of the emissions of those pollutants. The study consisted of a statistical analysis of the emissions of CO and HC of a composed sample for 384 vehicles with mechanization Gasoline/CNG or Alcohol/Gasoline/CNG of the municipal district of Natal-RN. The tests were accomplished in vehicles submitted to Vehicular Safety's Inspection, in the facilities of INSPETRANS, Organism of Vehicular Inspection. An partial gases analyzer allowed to measure, for each vehicle, the levels of CO and HC in two conditions of rotation of the motor (900 and 2500 rpm). The statistical analysis accomplished through the STATISTICA software revealed a sensitive reduction in the efficiency of the converters catalytic after 6 years of use with emission average it is of 0,78% of CO and 156 (ppm) of HC, Which represents approximately 4 (four) times the amount of CO and the double of HC in comparison with the newest vehicles. The result of a Student s t-test, suggests strongly that the average of the emissions of HC (152 ppm), at 900 rpm, is 40% larger than at 2500 rpm, for the motor without load. This result reveals that the efficiency of the catalytic conversion is limited kinetically in low engine speeds. The Study also ends that when comparing the emissions of CO and HC considering the influence of the fuels, it was verified that although the emissions of CO starting from CNG are 62% smaller than arising from the gasoline, there are not significant differences among the emissions of HC originating from of CNG and of the gasoline. In synthesis, the results place the current criteria of vehicular inspection, for exhaust gases, in doubt, leading the creation of emission limits of pollutant more rigorous, because the efficiency of the converters catalytic is sensibly reduced starting from 6 years of use. It is also raised the possibility of modifications in the test conditions adopted by the current norms, specifically in the speed engine, have seen that in the condition without load the largest emission indexes were registered in slow march. That fact that allows to suggest the dismissal of the tests in high speed engine, reducing the time of inspection in half and generating economy of fuel
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The use of waste heat of energy conversion equipment to produce a cooling effect, consists currently in a very interesting way of efficiency improvement of energy systems. The present research has as intention the theoretical and experimental study of a new intermittent refrigeration system ejector cycle characteristics, with use of waste heat. Initially, was doing a bibliographical survey about the vapor ejector refrigeration system technology. In the following stage was doing a simulation of the corresponding thermodynamic cycle, with preliminarily intention to evaluate the performance of the system for different refrigerants fluids. On the basis of the results of the simulation were selected the refrigerant fluid and developed an experimental group of benches of the refrigeration system considered, where pressure and temperature sensory had been inserted in strategical points of the refrigeration archetype and connected to a computerized data acquisition system for measure the refrigerant fluid properties in the thermodynamic cycle. The test results obtained show good agreement with the literature
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Experiments were performed to study the effect of surface properties of a vertical channel heated by a source of thermal radiation to induce air flow through convection. Two channels (solar chimney prototype) were built with glass plates, forming a structure of truncated pyramidal geometry. We considered two surface finishes: transparent and opaque. Each stack was mounted on a base of thermal energy absorber with a central opening for passage of air, and subjected to heating by a radiant source comprises a bank of incandescent bulbs and were performed field tests. Thermocouples were fixed on the bases and on the walls of chimneys and then connected to a data acquisition system in computer. The air flow within the chimney, the speed and temperature were measured using a hot wire anemometer. Five experiments were performed for each stack in which convective flows were recorded with values ranging from 17 m³ / h and 22 m³ / h and air flow velocities ranging from 0.38 m / s and 0.56 m / s for the laboratory tests and air velocities between 0.6 m/s and 1.1m/s and convective airflows between 650 m³/h and 1150 m³/h for the field tests. The test data were compared to those obtained by semi-empirical equations, which are valid for air flow induced into channels and simulated data from 1st Thermodynamics equation. It was found that the chimney with transparent walls induced more intense convective flows than the chimney with matte finish. Based on the results obtained can be proposed for the implementation of prototype to exhaust fumes, mists, gases, vapors, mists and dusts in industrial environments, to help promote ventilation and air renewal in built environments and for drying materials, fruits and seeds
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In this study were projected, built and tested an electric solar dryer consisting of a solar collector, a drying chamber, an exhaust fan and a fan to promote forced hot air convection. Banana drying experiments were also carried out in a static column dryer to model the drying and to obtain parameters that can be used as a first approximation in the modeling of an electric solar dryer, depending on the similarity of the experimental conditions between the two drying systems. From the banana drying experiments conducted in the static column dryer, we obtained food weight data as a function of aqueous concentration and temperature. Simplified mathematical models of the banana drying were made, based on Fick s and Fourier s second equations, which were tested with the experimental data. We determined and/or modeled parameters such as banana moisture content, density, thin layer drying curves, equilibrium moisture content, molecular diffusivity of the water in banana DAB, external mass transfer coefficient kM, specific heat Cp, thermal conductivity k, latent heat of water evaporation in the food Lfood, time to heat food, and minimum energy and power required to heat the food and evaporate the water. When we considered the shrinkage of radius R of a banana, the calculated values of DAB and kM generally better represent the phenomenon of water diffusion in a solid. The latent heat of water evaporation in the food Lfood calculated by modeling is higher than the latent heat of pure water evaporation Lwater. The values calculated for DAB and KM that best represent the drying were obtained with the analytical model of the present paper. These values had good agreement with those assessed with a numeric model described in the literature, in which convective boundary condition and food shrinkage are considered. Using parameters such as Cp, DAB, k, kM and Lfood, one can elaborate the preliminary dryer project and calculate the economy using only solar energy rather than using solar energy along with electrical energy
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The development of research that aim to reduce or even eliminate the environmental impacts provided by anthropogenic actions. One of these main action is the discard of industrial waste in the biotic compartments such as soil, water and air, gained more space in academic settings and in private. A technique of phytoremediation involving the use of plants (trees, shrubs, creepers and aquatic) and their associated microorganisms in order to remove, degrade or isolate toxic substances to the environment. This study aimed to evaluate the potential for phytoremediation of castor bean (Ricinus communis L.) and sunflower (Helianthus annuus L.), wild crops suitable region of Rio Grande do Norte, to reduce concentrations of lead and toluene present in synthetic wastewater that simulate the characteristics of treated water production originated in the petrochemical Guamaré. The experiment was accomplished in randomized blocks in four replicates. Seeds of BRS Energy for the development of seedlings of castor beans and sunflower for Catissol 01, both provided by EMPARN (Empresa de Pesquisa Agropecuária do Rio Grande do Norte) were used. Lead concentrations tested were 250, 500 and 1000 mg/L called T2, T3 and T4, respectively, for toluene the concentrations used were 125, 256 and 501 μg/L, called T5, T6 and T7, respectively. The data for removal of lead in relation to sewage systems applied in castor bean and sunflower were 43.89 and 51.85% (T2), 73.60 and 73.74% (T3) and 85.66 and 87.80 % (T4), respectively, and toluene were approximately 52.12 and 25.54% (T5), 55.10 and 58.05% (T6) and 79.77 and 74.76% (T7) for castor and sunflower seeds, respectively. From the data obtained, it can be deduce that mechanisms involved in reducing the contaminants were of phytoextraction, in relation to lead and phytodegradation for toluene. However, it can be concluded that the castor bean and sunflower crops can be used in exhaust after-treatment of industrial effluents that have this type of contaminant
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In the last decade, biological purification of gaseous waste has become an important alternative to many conventional methods of exhaust air treatment. More recently, biofiltration has proved to be an effective and inexpensive method for the treatment of air contaminated with volatile organic compounds (VOCs). A biofilter consists in a reactor packed with a porous solid bed material, where the microorganisms are fixed. During the biofiltration process, polluted air is transported through the biofilter medium where the contaminant is degraded. Within the biofilm, the pollutants in the waste gases are energy and carbon sources for microbial metabolism and are transformed into CO2, water and biomass. The bed material should be characterized by satisfactory mechanical and physical properties as structure, void fraction, specific area and flow resistance. The aim of this research was the biofilter construction and study of the biological degradation of ethanol and toluene, as well as the modeling of the process. Luffa cylindrica is a brazilian fiber that was used as the filtering material of the present work. The parameters and conditions studied were: composition of nutrients solution; effect of microflorae strains, namely Pseudomanas putida and Rhodococcus rhodochrous; waste gas composition; air flow rate; and inlet load of VOCs. The biofilter operated in diffusion regime and the best results for remotion capacity were obtained when a microorganisms consortion of Pseudomanas putida and Rhodococcus rhodochrous,were used, with a gas flow rate of 1 m3.h-1 and molar ratio nitrogene/phosphore N/P=2 in the nutrients solution. The maximum remotion capacity for ethanol was around 90 g.m-3.h-1 and 50 g.m-3.h-1 to toluene. It was proved that toluene has inhibitory effect on the ethanol remotion When the two VOCs were present in the same waste gas, there was a decrease of 40% in ethanol remotion capacity. Luffa cylindrica does not present considerable pressure drop. Ottengraf and van Lith models were used to represent the results obtained for ethanol and toluene, respectively. The application of the transient model indicated a satisfactory approximation between the experimental results obtained for ethanol and toluene vapors biofiltration and the ones predicted it
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This article presents an thermoeconomic analysis of cogeneration plants, applied as a rational technique to produce electric power and saturated steam. The aim of this new methodology is the minimum exergetic manufacturing cost (EMC), based on the Second Law of Thermodynamics. The decision variables selected for the optimization are the pressure and the temperature of the steam leaving the boiler in the case of using steam turbine, and the pressure ratio, turbine exhaust temperature and mass flow in the case of using gas turbines. The equations for calculating the capital costs of the components and products are formulated as a function of these decision variables. An application of the method using real data of a multinational chemical industry located in São Paulo state is presented. The conditions which establish the minimum cost are presented as finals conclusions.
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The increase in the use of natural gas in Brazil has stimulated public and private sectors to analyse the possibility of using combined cycle systems for generation of electrical energy. Gas turbine combined cycle power plants are becoming increasingly common due to their high efficiency, short lead times, and ability to meet environmental standards. Power is produced in a generator linked directly to the gas turbine. The gas turbine exhaust gases are sent to a heat recovery steam generator to produce superheated steam that can be used in a steam turbine to produce additional power. In this paper a comparative study between a 1000 MW combined cycle power plant and 1000 kW diesel power plant is presented. In first step, the energetic situation in Brazil, the needs of the electric sector modification and the needs of demand management and integrated means planning are clarified. In another step the characteristics of large and small thermoelectric power plants that use natural gas and diesel fuel, respectively, are presented. The ecological efficiency levels of each type of power plant is considered in the discussion, presenting the emissions of particulate material, sulphur dioxide (SO2), carbon dioxide (CO2) and nitrogen oxides (NOx). (c) 2006 Elsevier Ltd. All rights reserved.