986 resultados para CHARGED ELECTROPHILES
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[ES]El objetivo de este proyecto es diseñar y construir un circuito identificador y conmutador para carga de baterías en serie autónomo. La funcionalidad de este dispositivo es determinar cual es la batería menos cargada de un banco de baterías de ácido plomo que alimenta un coche al estándar de 48 voltios(conformado por cuatro baterías de 12 voltios). Una vez determinado cual es la batería menos cargada debe re-‐ direccionar la corriente dada por una placa solar a dicha batería. Todo esto debe hacerlo de forma autónoma, a través de un programa específico, implementado en un microcontrolador. En las diferentes fases del proyecto se ha diseñado el software, se ha diseñado y montado el hardware y se ha verificado su correcto funcionamiento. Además se presentan los costes y la viabilidad de una propuesta de fabricación estandarizada a partir de los planos resultantes del proyecto. Este proyecto surge como respuesta a la actual necesidad de aumentar la limitada autonomía de los coches eléctricos y hacerlos más eficientes. El proyecto se ha llevado a cabo en el laboratorio de electrónica de la ETSI de Bilbao y pretende promover el uso de los coches eléctricos y energías renovables.
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The fields of organic electronics and spintronics have the potential to revolutionize the electronics industry. Finding the right materials that can retain their electrical and spin properties when combined is a technological and fundamental challenge. We carry out the study of three archetypal organic molecules in intimate contact with the BiAg2 surface alloy. We show that the BiAg2 alloy is an especially suited substrate due to its inertness as support for molecular films, exhibiting an almost complete absence of substrate-molecular interactions. This is inferred from the persistence of a completely unaltered giant spin-orbit split surface state of the BiAg2 substrate, and from the absence of significant metallic screening of charged molecular levels in the organic layer. Spin-orbit split states in BiAg2 turn out to be far more robust to organic overlayers than previously thought.
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Este trabalho pretende comparar o ensino da produção textual em livros didáticos do português (LDP) e em apostilas escolares (AE), as quais hoje apontam para uma opção mercadológica de mercantilização do conhecimento escolar brasileiro. Como metodologia da pesquisa, optamos por um levantamento diacrônico sobre o ensino de Língua Portuguesa no Brasil, apresentando um histórico do LD como suporte de ensino e de aprendizagem da disciplina, para analisarmos os impactos das teorias linguísticas modernas, sobretudo, no que diz respeito aos gêneros discursivos (cf. Bakhtin, 2003), e dos PCN/PCNEM no ensino da produção de textos em sala de aula. Em virtude das modificações recentemente propostas pelo Exame Nacional de Ensino Médio (ENEM) e dos seus impactos na abordagem escolar da Produção Textual (PT), delimitamos nossa análise ao gênero dissertação escolar (DE), conhecido genericamente como redação escolar (RE), o mais cobrado em concursos e vestibulares brasileiros, traçando um recorte desde o período pós-Ditadura até as recentes propostas semióticas de abordagem do gênero (BARTHES, 1975; SANTAELLA, 2009; SIMÕES, 2009). Nossa perspectiva é, à guisa das mudanças ideológicas envolvidas na mudança de abordagem do ensino de RE para PT, apontar como LDP, tradicionalmente adotados em escolas públicas, e AE, contemporaneamente preferidas por dirigentes de escolas particulares, comportam-se frente a quatro eixos fundamentais para a prática docente do ensino da dissertação escolar: concepções teóricas adotadas, metodologia do ensino de DE, fundamentação teórico-metodológica dos professores e propostas de avaliação. Feita a análise contrastiva, o trabalho apontará aspectos divergentes e convergentes desse ensino, contextualizando o papel docente como mediador diante dos conflitos pedagógicos surgidos no decorrer da educação básica
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Estimating rare events from zero-heavy data (data with many zero values) is a common challenge in fisheries science and ecology. For example, loggerhead sea turtles (Caretta caretta) and leatherback sea turtles (Dermochelys coriacea) account for less than 1% of total catch in the U.S. Atlantic pelagic longline fishery. Nevertheless, the Southeast Fisheries Science Center (SEFSC) of the National Marine Fisheries Service (NMFS) is charged with assessing the effect of this fishery on these federally protected species. Annual estimates of loggerhead and leatherback bycatch in a fishery can affect fishery management and species conservation decisions. However, current estimates have wide confidence intervals, and their accuracy is unknown. We evaluate 3 estimation methods, each at 2 spatiotemporal scales, in simulations of 5 spatial scenarios representing incidental capture of sea turtles by the U.S. Atlantic pelagic longline fishery. The delta-log normal method of estimating bycatch for calendar quarter and fishing area strata was the least biased estimation method in the spatial scenarios believed to be most realistic. This result supports the current estimation procedure used by the SEFSC.
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4th International Workshop on Transverse Polisarization Phenomena in Hard Processes (TRANSVERSITY 2014)
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Ensaio não destrutivo é uma ferramenta essencial quando um equipamento, dispositivo ou componente não pode ser submetido a procedimentos destrutivos ou invasivos devido a razões de segurança, alto custo ou outras restrições físicas ou logísticas. Dentro deste quadro radiografias por transmissão com raios gama e nêutrons térmicos são técnicas singulares para inspecionar um objeto e desvendar sua estrutura interna devido à capacidade de atravessar uma vasta gama de materiais utilizados na indústria. Grosso modo, raios gama são mais atenuados por materiais pesados enquanto nêutrons térmicos são mais atenuados por materiais mais leves, tornando-as ferramentas complementares. Este trabalho apresenta os resultados obtidos na inspeção de vários componentes mecânicos, através da radiografia por transmissão com nêutrons térmicos e raios gama. O fluxo de nêutrons térmicos de 4,46x105 n.cm-2.s-1 disponível no canal principal do reator de pesquisa Argonauta do Instituto de Engenharia Nuclear foi usado como fonte para as imagens radiográficas com nêutrons. Raios dekeV emitidos pelo 198Au, também produzido no reator, foram usados como fonte de radiação para radiografias . Imaging Plates, especificamente produzidos para operar com nêutrons térmicos ou com raios X, foram empregados como detectores e dispositivos de armazenamento e captação de imagens para cada uma dessas radiações. Esses dispositivos exibem varias vantagens quando comparados ao filme radiográfico convencional. Com efeito, além de maior sensibilidade e serem reutilizáveis não são necessários câmaras escuras e processamento químico para a revelação. Em vez disso, ele é lido por um feixe de laser que libera elétrons armadilhados na rede cristalina durante a exposição à radiação, fornecendo uma imagem final digital. O desempenho de ambos os sistemas de aquisição de imagens, assim constituído, foi avaliado com respeito à sensibilidade, resolução espacial, linearidade e range dinâmico, incluído uma comparação com sistemas radiográficos com nêutrons empregando filmes e folhas de gadolínio como conversor de nêutrons em partículas carregadas. Além desta caracterização, diversos equipamentos e componentes foram radiografados com ambos os sistemas visando-se avaliar suas capacidades de desvendar a estrutura interna desses objetos e detectar estruturas e estados anormais. Dentro desta abordagem, uma neutrongrafia detectou a presença de material cerâmico remanescente empregado como molde no processo de fabricação nos canais de refrigeração de uma aleta do estator de uma turbina tipo turbo-fan, que deveria estar livre desse material. O reostato danificado de um sensor de pressão automotivo, foi identificado por neutrongrafia, embora nesse caso a radiografia também conseguiu realizar essa tarefa com melhor resolução, corroborando assim as curvas de resolução espacial obtidas na caracterização dos dois sistemas. A homogeneidade da distribuição do material encapsulado em uma gaxeta explosiva de chumbo utilizada na indústria aeroespacial foi igualmente verificada por neutrongrafia porque esse metal é relativamente transparente para nêutrons, mas suficientemente opaco para o explosivo rico em hidrogênio. Diversos outros instrumentos e componentes tais como variômetro, altímetro, bússola aeronáutica, injetor automotivo de combustível, foto-camera, disco rígido de computador, motor de passo, conectores eletrônicos e projéteis foram radiografados com ambos os sistemas visando avaliar suas habilidades em desvendar diferentes peculiaridades em função do agente interrogador.
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For purposes ofthe Endangered Species Act (ESA), a "species" is defined to include "any distinct population segment of any species of vertebrate fish or wildlife which interbreeds when mature. "Federal agencies charged with carrying out the provisions of the ESA have struggled for over a decade to develop a consistent approach for interpreting the term "distinct population segment." This paper outlines such an approach and explains in some detail how it can be applied to ESA evaluations of anadromous Pacific salmonids. The following definition is proposed: A population (or group of populations) will be considered "distinct" (and hence a "species ")for purposes of the ESA if it represents an evolutionarily significant unit (ESU) of the biological species. A population must satisfy two criteria to be considered an ESU: 1) It must be substantially reproductively isolated from other conspecific population units, and 2) It must represent an important component in the evolutionary legacy of the species. Isolation does not have to be absolute, but it must be strong enough to permit evolutionarily important differences to accrue in different population units. The second criterion would be met if the population contributes substantially to the ecological/genetic diversity of the species as a whole. Insights into the extent of reproductive isolation can be provided by movements of tagged fish, natural recolonization rates observed in other populations, measurements of genetic differences between populations, and evaluations of the efficacy of natural barriers. Each of these methods has its limitations. Identification of physical barriers to genetic exchange can help define the geographic extent of distinct populations, but reliance on physical features alone can be misleading in the absence of supporting biological information. Physical tags provide information about the movements of individual fish but not the genetic consequences of migration. Furthermore, measurements ofc urrent straying or recolonization rates provide no direct information about the magnitude or consistency of such rates in the past. In this respect, data from protein electrophoresis or DNA analyses can be very useful because they reflect levels of gene flow that have occurred over evolutionary time scales. The best strategy is to use all available lines of evidence for or against reproductive isolation, recognizing the limitations of each and taking advantage of the often complementary nature of the different types of information. If available evidence indicates significant reproductive isolation, the next step is to determine whether the population in question is of substantial ecological/genetic importance to the species as a whole. In other words, if the population became extinct, would this event represent a significant loss to the ecological/genetic diversity of thes pecies? In making this determination, the following questions are relevant: 1) Is the population genetically distinct from other conspecific populations? 2) Does the population occupy unusual or distinctive habitat? 3) Does the population show evidence of unusual or distinctive adaptation to its environment? Several types of information are useful in addressing these questions. Again, the strengths and limitations of each should be kept in mind in making the evaluation. Phenotypic/life-history traits such as size, fecundity, and age and time of spawning may reflect local adaptations of evolutionary importance, but interpretation of these traits is complicated by their sensitivity to environmental conditions. Data from protein electrophoresis or DNA analyses provide valuable insight into theprocessofgenetic differentiation among populations but little direct information regarding the extent of adaptive genetic differences. Habitat differences suggest the possibility for local adaptations but do not prove that such adaptations exist. The framework suggested here provides a focal point for accomplishing the majorgoal of the Act-to conserve the genetic diversity of species and the ecosystems they inhabit. At the same time, it allows discretion in the listing of populations by requiring that they represent units of real evolutionary significance to the species. Further, this framework provides a means of addressing several issues of particular concern for Pacific salmon, including anadromous/nonanadromous population segments, differences in run-timing, groups of populations, introduced populations, and the role of hatchery fish.
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A proposta deste trabalho é de criar receita e renda para comunidades de baixa renda e, de certa forma chamar a atenção da sociedade para esta necessidade, ou seja, a de gerar mecanismos de melhoria da renda familiar. Através dos Postos de Troca, as pessoas residentes em comunidades atendidas pelo Programa Comunidade Eficiente, administrado pela Light junto a ANEEL, poderão trocar seus recicláveis por descontos em suas contas de energia elétrica. Os resíduos sólidos recicláveis possíveis por uma família de comunidade de baixa renda têm potencialidade em torno de 11,69 kg /mês, tendo sido estimada uma receita mensal por família de R$1,30. Este valor representa 40% da tarifa mínima cobrada pela Light, que é muito usual para esta classe de clientes. A viabilidade de implantação dos Postos de troca pode ser possível desde que haja um prazo mínimo para retorno do investimento de pelo menos 24 meses.
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A teoria magneto-hidrodinâmicos permite a estruturação de modelos computacionais, designados modelos MHDs, que são uma extensão da dinâmica dos fluidos para lidar com fluidos eletricamente carregados, tais como os plasmas, em que se precisa considerar os efeitos de forças eletromagnéticas. Tais modelos são especialmente úteis quando o movimento exato de uma partícula não é de interesse, sendo que as equações descrevem as evoluções de quantidades macroscópicas. Várias formas de modelos MHD têm sido amplamente utilizadas na Física Espacial para descrever muitos tipos diferentes de fenômenos de plasma, tais como reconexão magnética e interações de ventos estelares com diferentes objetos celestiais. Neste trabalho, o objetivo é analisar o comportamento de diversos fluxos numéricos em uma discretização de volumes finitos de um modelo numérico de MHD usando um esquema de malha entrelaçada sem separação direcional considerando alguns casos testes. Para as simulações, utiliza-se o código Flash, desenvolvido pela Universidade de Chicago, por ser um código de amplo interesse nas simulações astrofísicas e de fenômenos no espaço próximo à Terra. A metodologia consiste na inclusão de um fluxo numérico, permitindo melhoria com respeito ao esquema HLL.
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Reef fishes are conspicuous and essential components of coral reef ecosystems and economies of southern Florida and the United States Virgin Islands (USVI). Throughout Florida and the USVI, reef fish are under threat from a variety of anthropogenic and natural stressors including overfishing, habitat loss, and environmental changes. The South Florida/Caribbean Network (SFCN), a unit of the National Park Service (NPS), is charged with monitoring reef fishes, among other natural and cultural resources, within six parks in the South Florida - Caribbean region (Biscayne National Park, BISC; Buck Island Reef National Monument, BUIS; Dry Tortugas National Park, DRTO; Everglades National Park, EVER; Salt River Bay National Historic Park and Ecological Preserve, SARI; Virgin Islands National Park, VIIS). Monitoring data is intended for park managers who are and will continue to be asked to make decisions to balance environmental protection, fishery sustainability and park use by visitors. The range and complexity of the issues outlined above, and the need for NPS to invest in a strategy of monitoring, modeling, and management to ensure the sustainability of its precious assets, will require strategic investment in long-term, high-precision, multispecies reef fish data that increases inherent system knowledge and reduces uncertainty. The goal of this guide is to provide the framework for park managers and researchers to create or enhance a reef fish monitoring program within areas monitored by the SFCN. The framework is expected to be applicable to other areas as well, including the Florida Keys National Marine Sanctuary and Virgin Islands Coral Reef National Monument. The favored approach is characterized by an iterative process of data collection, dataset integration, sampling design analysis, and population and community assessment that evaluates resource risks associated with management policies. Using this model, a monitoring program can adapt its survey methods to increase accuracy and precision of survey estimates as new information becomes available, and adapt to the evolving needs and broadening responsibilities of park management.
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Technological innovation has made it possible to grow marine finfish in the coastal and open ocean. Along with this opportunity comes environmental risk. As a federal agency charged with stewardship of the nation’s marine resources, the National Oceanic and Atmospheric Administration (NOAA) requires tools to evaluate the benefits and risks that aquaculture poses in the marine environment, to implement policies and regulations which safeguard our marine and coastal ecosystems, and to inform production designs and operational procedures compatible with marine stewardship. There is an opportunity to apply the best available science and globally proven best management practices to regulate and guide a sustainable United States (U.S.) marine finfish farming aquaculture industry. There are strong economic incentives to develop this industry, and doing so in an environmentally responsible way is possible if stakeholders, the public and regulatory agencies have a clear understanding of the relative risks to the environment and the feasible solutions to minimize, manage or eliminate those risks. This report spans many of the environmental challenges that marine finfish aquaculture faces. We believe that it will serve as a useful tool to those interested in and responsible for the industry and safeguarding the health, productivity and resilience of our marine ecosystems. This report aims to provide a comprehensive review of some predominant environmental risks that marine fish cage culture aquaculture, as it is currently conducted, poses in the marine environment and designs and practices now in use to address these environmental risks in the U.S. and elsewhere. Today’s finfish aquaculture industry has learned, adapted and improved to lessen or eliminate impacts to the marine habitats in which it operates. What progress has been made? What has been learned? How have practices changed and what are the results in terms of water quality, benthic, and other environmental effects? To answer these questions we conducted a critical review of the large body of scientific work published since 2000 on the environmental impacts of marine finfish aquaculture around the world. Our report includes results, findings and recommendations from over 420 papers, primarily from peer-reviewed professional journals. This report provides a broad overview of the twenty-first century marine finfish aquaculture industry, with a targeted focus on potential impacts to water quality, sediment chemistry, benthic communities, marine life and sensitive habitats. Other environmental issues including fish health, genetic issues, and feed formulation were beyond the scope of this report and are being addressed in other initiatives and reports. Also absent is detailed information about complex computer simulations that are used to model discharge, assimilation and accumulation of nutrient waste from farms. These tools are instrumental for siting and managing farms, and a comparative analysis of these models is underway by NOAA.
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Coral reef ecosystems are some of the most complex and important ecosystems in the marine environment. They are also among the most biologically diverse and economically valuable ecosystems on earth, producing billions of dollars in food, as well as providing a suite of ecological services, such as recreation and tourism activities and coastal protection from storm and wave action. Yet, despite their value and importance, these fragile ecosystems are declining at an alarming rate (Waddell and Clarke (eds.) 2008) due to a myriad of threats both natural and manmade, including climate change, fishing pressure, and runoff and sedimentation. In response, the Unites States Coal Reef Task Force was established in 1998 by Presidential Executive Order 13089 to lead U.S. efforts to preserve and protect the nation’s coral reef ecosystems. In order to better understand the current state of coral reef ecosystems and successfully mitigate the impacts of stressors, informational products, such as benthic (or sea floor) habitat maps, are critical. Benthic habitat maps support the ability to prioritize areas for further study and protection, and offer a baseline to evaluate the changes in ecosystems over time. In 2000, the United States Coral Reef Task Force charged NOAA with leading federal efforts to produce comprehensive digital maps of all U.S. shallow-water (approximately 0 to 30 m in depth) coral reef ecosystem habitats.
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The National Oceanic and Atmospheric Administration (NOAA) National Ocean Service (NOS) initiated a coral reef research program in 1999 to map, assess, inventory, and monitor U.S. coral reef ecosystems (Monaco et al. 2001). These activities were implemented in response to requirements outlined in the Mapping Implementation Plan developed by the Mapping and Information Synthesis Working Group (MISWG) of the Coral Reef Task Force (CRTF) (MISWG 1999). As part of the MISWG of the CRTF, NOS' Biogeography Branch has been charged with the development and implementation of a plan to produce comprehensive digital coral-reef ecosystem maps for all U.S. States, Territories, and Commonwealths within five to seven years. Joint activities between Federal agencies are particularly important to map, research, monitor, manage, and restore coral reef ecosystems. In response to the Executive Order 13089 and the Coral Reef Conservation Act of 2000, NOS is conducting research to digitally map biotic resources and coordinate a long-term monitoring program that can detect and predict change in U.S. coral reefs, and their associated habitats and biological communities. Most U.S. coral reef resources have not been digitally mapped at a scale or resolution sufficient for assessment, monitoring, and/or research to support resource management. Thus, a large portion of NOS' coral reef research activities has focused on mapping of U.S. coral reef ecosystems. The map products will provide the fundamental spatial organizing framework to implement and integrate research programs and provide the capability to effectively communicate information and results to coral reef ecosystem managers. Although the NOS coral program is relatively young, it has had tremendous success in advancing towards the goal to protect, conserve, and enhance the health of U.S. coral reef ecosystems. One objective of the program was to create benthic habitat maps to support coral reef research to enable development of products that support management needs and questions. Therefore this product was developed in collaboration with many U.S. Pacific Territory partners. An initial step in producing benthic habitat maps was the development of a habitat classification scheme. The purpose of this document is to outline the benthic habitat classification scheme and protocols used to map American Samoa, Guam and the Commonwealth of the Northern Mariana Islands. Thirty-two distinct benthic habitat types (i.e., four major and 14 detailed geomorphological structure classes; eight major and 18 detailed biological cover types) within eleven zones were mapped directly into a geographic information system (GIS) using visual interpretation of orthorectified IKONOS satellite imagery. Benthic features were mapped that covered an area of 263 square kilometers. In all, 281 square kilometers of unconsolidated sediment, 122 square kilometers of submerged vegetation, and 82.3 square kilometers of coral reef and colonized hardbottom were mapped.
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Hydrogenated amorphous silicon (a-Si:H) thin films have been deposited from silane using a novel photo-enhanced decomposition technique. The system comprises a hydrogen discharge lamp contained within the reaction vessel; this unified approach allows high energy photon excitation of the silane molecules without absorption by window materials or the need for mercury sensitisation. The film growth rates (exceeding 4 Angstrom/s) and material properties obtained are comparable to those of films produced by plasma-enhanced CVD techniques. The reduction of energetic charged particles in the film growth region should enable the fabrication of cleaner semiconductor/insulator interfaces in thin-film transistors.