896 resultados para Gear efficiency and gear selectivity
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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In an attempt to optimize a high yield, high efficiency artificial photosynthetic protein we have discovered unique energy and spatial architecture limits which apply to all light-activated photosynthetic systems. We have generated an analytical solution for the time behavior of the core three cofactor charge separation element in photosynthesis, the photosynthetic cofactor triad, and explored the functional consequences of its makeup including its architecture, the reduction potentials of its components, and the absorption energy of the light absorbing primary-donor cofactor. Our primary findings are two: First, that a high efficiency, high yield triad will have an absorption frequency more than twice the reorganization energy of the first electron transfer, and second, that the relative distance of the acceptor and the donor from the primary-donor plays an important role in determining the yields, with the highest efficiency, highest yield architecture having the light absorbing cofactor closest to the acceptor. Surprisingly, despite the increased complexity found in natural solar energy conversion proteins, we find that the construction of this central triad in natural systems matches these predictions. Our analysis thus not only suggests explanations for some aspects of the makeup of natural photosynthetic systems, it also provides specific design criteria necessary to create high efficiency, high yield artificial protein-based triads.
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Incluye bibliografía
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At this time, each major automotive market bares its own standards and test procedures to regulate the vehicle green house gases emissions and, thus, fuel consumption. Hence, much are the ways to evaluate the overall efficiency of motor vehicles. The majority of such standards rely on dynamometer cycle tests that appraise only the vehicle as a whole, but fail to assess emissions for each component or sub-system. Once the amount of work generated by the power source of an ICE vehicle to overcome the driving resistance forces is proportional to the energy contained in the required amount of fuel, the power path of the vehicle can be straightforwardly modeled as a set of mechanical systems, and each sub-system evaluated for its share on the total fuel consumption and green house gases emission. This procedure enables the estimation of efficiency gains on the system due to improvement of particular elements on the vehicle's driveline. In this work a simple systematic mechanical model of an arbitrary smallsized hatch back was assembled and total required energy calculated for different regulatory cycles. All the modeling details of the energy balance throughout the system are presented. Afterward, each subsystem was investigated for its role on the fuel consumption and the generated emission quantified. Furthermore, the application of the modeling technique for different sets of sub-systems was introduced. Copyright © 2011 SAE International.
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The use of the Internet as a means of ensuring greater visibility for products, services and information offered by companies is gaining strength in recent decades. However, it is known that to ensure satisfaction and subsequent virtual customer loyalty, it is necessary to guarantee the quality of the websites, allowing indiscriminate access regardless of the resources used, as well as rapid responses to possible requests. In order to assist this process, this paper presents a set of guidelines for the development of websites having quality characteristics, efficiency and portability as per ISO 9126 norms. An observational analysis of e-commerce websites was done which showed that they are inadequate as to the proposed guidelines, making them difficult to access available content. Therefore, the adoption of the proposed guidelines can greatly contribute to increasing the quality of websites and, consequently, enable quick and effective access regardless of the resources used.
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Includes bibliography
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Brazil is the world's largest producer of sugar cane and which in the state of São Paulo concentrate the greatest amount of sugar cane field of the country. The sugar-alcohol sector has the capacity to produce sufficient thermal and electrical energy to be used in their process of production and commercialize of surplus in electricity distribution network. Therefore it is necessary to evaluate the energy efficiency and rationality within the mill. Accordingly this research proposed analyze the sugar-alcohol mill's sectors globally and individually, located in the west center of the São Paulo state, using the valuation methodology employed by the Agência Nacional de Energia Elétrica (ANEEL) in the industries that do not have systems of cogeneration. In this analysis, the hyperboloids of load and potency were applied based on the indexes of potency factor and load factor that allow estimate the efficiency and rationality. © 2013 IEEE.
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Includes bibliography.
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Much analysis and proposals on sustainable transport policies have been developed around the world, both at government and research institutions. It is clear that no action will provide the single solution and it is imperative to act simultaneously on: i) improvement of technology in vehicles, leading to increased energy efficiency; ii) the change in driver behavior, to use less fuel per kilometer; iii) reducing the distances traveled per vehicle; and iv) a change in the type of travels towards more sustainable modes of transport.In general, the recommendations for energy efficiency in transport are mainly focused on the first two priorities on the list, while the portfolios of policies —instrumental to the needs of the countries— should use trans-sectoral and multi-dimensional approaches, such as public transport planning and land use. In ECLAC, we consider that the time has come to provide Latin American and Caribbean countries with a deeper understanding and a more strategic vision (and adapted to the realities of the region) on these issues; in this sense, we hope that this document will help countries to improve and further expand their portfolios of energy efficiency policies in the transport sector, in order to achieve the ambitious goals of energy efficiency, needed to ensure a sustainable energy future.
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Belize is currently faced with several critical challenges associated with the production, distribution and use of energy. Despite an abundance of renewable energy resources, the country remains disproportionately dependent on imported fossil fuels, which exposes it to volatile and rising oil prices, limits economic development, and retards its ability to make the investments that are necessary for adapting to climate change, which pose a particularly acute threat to the small island states and low-lying coastal nations of the Caribbean. This transition from energy consumption and supply patterns that are based on imported fossil fuels and electricity towards a more sustainable energy economy that is based on environmentally benign, indigenous renewable energy technologies and more efficient use of energy requires concerted action as the country is already challenged by limited fiscal space which reduces its ability to provide some fiscal incentives, which have been proven to be effective tools for the promotion of sustainable energy markets in a number of countries. This report identifies the fiscal and regulatory barriers to implementation of energy efficiency measures and renewable energy technologies in Belize. Data and information were derived from stakeholder consultations conducted within the country. The major result of the assessment is that the transition of policies and plans into tangible action needs to be increased. In this regard, it is necessary to articulate sub-policies of the National Energy Policy to amend the Public Utilities Commission Act, to develop a grid interconnection policy, to establish minimum energy performance standards for buildings and equipment and to develop a public procurement policy. Finally, decisions on renewable energy and energy efficiency-related incentives from the Government formally requires decision-makers to solve what may be extremely complex optimization problems in order to obtain the lowest-cost provision of energy services to society, thereby weighing the cost of revenue losses with the benefits of fuel and infrastructure expansion savings. The establishment of a management system that is efficient, flexible, and transparent, which will facilitate the implementation of the strategic objectives and outputs in the time available, with the financial resources allocated is recommended. Support is required for additional institutional and capacity strengthening.
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The current energy systems within Curaçao depend primarily on high cost, imported fossil fuels, and typically constitute power sectors that are characterized by small, inefficient generation plants which result in high energy prices. As a consequence of its dependence on external fuel supplies, Curaçao is extremely vulnerable to international oil price shocks, which can impact on economic planning and foreign direct investment within their industrial sectors. The ability of the successive governments to source capital for economic stimulation and social investment is therefore significantly challenging. Additionally, there is over-dependence on two of the most climate-sensitive economic sectors, namely the tourism and fisheries sectors, but the vulnerabilities of the country to the effects of climate change make adaptation difficult and costly. It is within this context that this report focuses on identification of the fiscal and regulatory barriers to implementation of energy efficiency and renewable energy technologies in Curaçao with a view of making recommendations for removal of these barriers. Consultations with key Government officials, the private sector as well as civil society were conducted to obtain information and data on the energy sector in the country. Desktop research was also conducted to supplement the information gathered from the consultations. The major result of the assessment is that Curaçao is at an early stage in the definition of its energy sector. Despite some infrastructural legacies of the pre-independence era, as well as a number of recent developments including the modernization and expansion of its windfarms and completion of a modern Electricity Policy, there are still a number of important institutional and policy gaps within the energy sector in Curaçao. The most significant deficiency is the absence of a ministry or Government agency with portfolio responsibility for the energy sector as a whole; this has: limited the degree to which the activities of energy sector stakeholders are coordinated and retarded the development and implementation of a comprehensive national energy policy. The absence of an energy policy, which provides the framework for energy planning, increases investor risk. Also, the lack of political continuity that has emanated from the frequent changes in Government administrations is a concern among stakeholders and has served to reduce investor confidence in particular, and market confidence in general.