31 resultados para Refração linear - Índice


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A agressividade é o comportamento que surge transversalmente como queixa isolada ou a par de outras queixas na maioria das crianças com e sem doença, que procuram apoio em saúde mental infantil. Nessas crianças, e a partir da recolha dos dados anamnesicos, tem-se verificado a constância de registo, no Livro do Bebé, de Índice de Apgar ≤ 9 ao primeiro minuto. Este estudo exploratório pretendeu analisar a hipótese teórica de que o Índice de Apgar abaixo de 10 ao primeiro minuto pode ser representativo de sofrimento fetal intraparto ou perinatal e assim fragilizar os circuitos neuronais das emoções tendo como consequência o surgimento, ao longo do desenvolvimento infantil e juvenil, de dificuldades na capacidade de gestão ou controlo das emoções, com comportamentos opositivos e/ou agressivos, como resposta defensiva de luta e fuga. Utilizou-se uma amostra de crianças inscritas no serviço de consulta externa de saúde mental infantil e juvenil, e verificou-se se as queixas de perturbação do comportamento com agressividade, formuladas no momento do acolhimento ao serviço, estão relacionadas com o Índice de Apgar ≤ 9 ao primeiro minuto e/ou com os registos de sofrimento fetal. Procurou-se, numa amostra aleatória de crianças sem queixa formulada no serviço de consulta externa de saúde mental infantil e juvenil, perceber as diferenças ou semelhanças dos registos de nascimento relativamente à amostra de crianças inscritas. Foi ainda auscultada a opinião dos profissionais dos serviços de obstetrícia e neonatologia – pediatria, mediante a aplicação de um questionário, no sentido de recolher as opiniões dos profissionais de saúde que lidam com o parto, que avaliam o Índice de Apgar dos recém – nascidos e que os seguem durante as primeiras horas ou dias de vida. Das conclusões a que chegamos, salienta-se que o sofrimento fetal intraparto pode ser predictor de dificuldades de controlo emocional traduzidas em alterações do comportamento com agressividade em situações de stress. Não se conclui que o Índice de Apgar ≤ 9 pode ser predictor de alterações do comportamento com agressividade em situações de stress, uma vez que os registos de ocorrências de sofrimento fetal intraparto e os registos do Índice de Apgar ao primeiro minuto são, na amostra de crianças com queixa, díspares, relacionando-se no entanto de modo estatisticamente significativo na amostra de crianças sem queixa. III No entanto, e apesar das dificuldades metodológicas, fica a certeza de haver mais percursos a percorrer nesta direcção para a compreensão dos distúrbios emocionais e a agressividade.

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In the energy management of the isolated operation of small power system, the economic scheduling of the generation units is a crucial problem. Applying right timing can maximize the performance of the supply. The optimal operation of a wind turbine, a solar unit, a fuel cell and a storage battery is searched by a mixed-integer linear programming implemented in General Algebraic Modeling Systems (GAMS). A Virtual Power Producer (VPP) can optimal operate the generation units, assured the good functioning of equipment, including the maintenance, operation cost and the generation measurement and control. A central control at system allows a VPP to manage the optimal generation and their load control. The application of methodology to a real case study in Budapest Tech, demonstrates the effectiveness of this method to solve the optimal isolated dispatch of the DC micro-grid renewable energy park. The problem has been converged in 0.09 s and 30 iterations.

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Electricity market players operating in a liberalized environment requires access to an adequate decision support tool, allowing them to consider all the business opportunities and take strategic decisions. Ancillary services represent a good negotiation opportunity that must be considered by market players. For this, decision support tools must include ancillary market simulation. This paper proposes two different methods (Linear Programming and Genetic Algorithm approaches) for ancillary services dispatch. The methodologies are implemented in MASCEM, a multi-agent based electricity market simulator. A test case concerning the dispatch of Regulation Down, Regulation Up, Spinning Reserve and Non-Spinning Reserve services is included in this paper.

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As indústrias de componentes e acessórios automóveis são um elo fundamental no processo produtivo da indústria automóvel. Neste leque industrial encontra-se a Preh Portugal, Lda, como empresa fornecedora de componentes electrónicos, mais concretamente, painéis de controlo de climatização. Os painéis fornecidos pela Preh aos seus clientes encontram-se sujeitos a rigorosos testes de qualidade e funcionalidade. Neste sentido o teste funcional das teclas surge, relacionando o curso da tecla em função de uma força actuante. Esta relação está comprometida com uma curva característica padrão para o tipo de tecla. Para além destes compromissos, também é necessário que a tecla feche e abra o seu contacto eléctrico. Esta tese foca-se no desenvolvimento do teste de teclas, apresentando uma alteração ao sistema actual com a introdução de um sistema embebido, no intuito de flexibilizar o sistema de teste e reduzindo custos. O sistema embebido pretende dar capacidade de processamento ao teste e, desta forma, substituir o actual computador como elemento de processamento. A solução implementada consistiu numa mudança estrutural, através da inclusão do sistema embebido entre o computador e o sistema de deslocamento. Passando o foco central do processo de teste a residir no sistema embebido, este tem de estabelecer comunicações com os restantes elementos intervenientes no teste. Estabelece comunicações série RS-232 com o sistema de deslocamento (leitura do curso e força na tecla), Ethernet com o computador (comandos, parâmetros e resultados) e CAN com o painel de controlo de climatização (fecho/abertura do contacto eléctrico). A concretização deste projecto resultou numa nova estrutura e aplicação, a qual é facilmente integrada na linha de produção com as vantagens de ser menos onerosa e mais flexível, conforme o pretendido.

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Screening of topologies developed by hierarchical heuristic procedures can be carried out by comparing their optimal performance. In this work we will be exploiting mono-objective process optimization using two algorithms, simulated annealing and tabu search, and four different objective functions: two of the net present value type, one of them including environmental costs and two of the global potential impact type. The hydrodealkylation of toluene to produce benzene was used as case study, considering five topologies with different complexities mainly obtained by including or not liquid recycling and heat integration. The performance of the algorithms together with the objective functions was observed, analyzed and discussed from various perspectives: average deviation of results for each algorithm, capacity for producing high purity product, screening of topologies, objective functions robustness in screening of topologies, trade-offs between economic and environmental type objective functions and variability of optimum solutions.

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Amulti-residue methodology based on a solid phase extraction followed by gas chromatography–tandem mass spectrometry was developed for trace analysis of 32 compounds in water matrices, including estrogens and several pesticides from different chemical families, some of them with endocrine disrupting properties. Matrix standard calibration solutions were prepared by adding known amounts of the analytes to a residue-free sample to compensate matrix-induced chromatographic response enhancement observed for certain pesticides. Validation was done mainly according to the International Conference on Harmonisation recommendations, as well as some European and American validation guidelines with specifications for pesticides analysis and/or GC–MS methodology. As the assumption of homoscedasticity was not met for analytical data, weighted least squares linear regression procedure was applied as a simple and effective way to counteract the greater influence of the greater concentrations on the fitted regression line, improving accuracy at the lower end of the calibration curve. The method was considered validated for 31 compounds after consistent evaluation of the key analytical parameters: specificity, linearity, limit of detection and quantification, range, precision, accuracy, extraction efficiency, stability and robustness.

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Ancillary services represent a good business opportunity that must be considered by market players. This paper presents a new methodology for ancillary services market dispatch. The method considers the bids submitted to the market and includes a market clearing mechanism based on deterministic optimization. An Artificial Neural Network is used for day-ahead prediction of Regulation Down, regulation-up, Spin Reserve and Non-Spin Reserve requirements. Two test cases based on California Independent System Operator data concerning dispatch of Regulation Down, Regulation Up, Spin Reserve and Non-Spin Reserve services are included in this paper to illustrate the application of the proposed method: (1) dispatch considering simple bids; (2) dispatch considering complex bids.

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In this work we present a classification of some of the existing Penalty Methods (denominated the Exact Penalty Methods) and describe some of its limitations and estimated. With these methods we can solve problems of optimization with continuous, discrete and mixing constrains, without requiring continuity, differentiability or convexity. The boarding consists of transforming the original problem, in a sequence of problems without constrains, derivate of the initial, making possible its resolution for the methods known for this type of problems. Thus, the Penalty Methods can be used as the first step for the resolution of constrained problems for methods typically used in by unconstrained problems. The work finishes discussing a new class of Penalty Methods, for nonlinear optimization, that adjust the penalty parameter dynamically.

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This paper addresses the use of multidimensional scaling in the evaluation of controller performance. Several nonlinear systems are analyzed based on the closed loop time response under the action of a reference step input signal. Three alternative performance indices, based on the time response, Fourier analysis, and mutual information, are tested. The numerical experiments demonstrate the feasibility of the proposed methodology and motivate its extension for other performance measures and new classes of nonlinearities.

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In this paper an algorithm for the calculation of the root locus of fractional linear systems is presented. The proposed algorithm takes advantage of present day computational resources and processes directly the characteristic equation, avoiding the limitations revealed by standard methods. The results demonstrate the good performance for different types of expressions.

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Aiming for teaching/learning support in sciences and engineering areas, the Remote Experimentation concept (an E-learning subset) has grown in last years with the development of several infrastructures that enable doing practical experiments from anywhere and anytime, using a simple PC connected to the Internet. Nevertheless, given its valuable contribution to the teaching/learning process, the development of more infrastructures should continue, in order to make available more solutions able to improve courseware contents and motivate students for learning. The work presented in this paper contributes for that purpose, in the specific area of industrial automation. After a brief introduction to the Remote Experimentation concept, we describe a remote accessible lab infrastructure that enables users to conduct real experiments with an important and widely used transducer in industrial automation, named Linear Variable Differential Transformer.

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Linear Algebra—Selected Problems is a unique book for senior undergraduate and graduate students to fast review basic materials in Linear Algebra. Vector spaces are presented first, and linear transformations are reviewed secondly. Matrices and Linear systems are presented. Determinants and Basic geometry are presented in the last two chapters. The solutions for proposed excises are listed for readers to references.

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This work deals with the numerical simulation of air stripping process for the pre-treatment of groundwater used in human consumption. The model established in steady state presents an exponential solution that is used, together with the Tau Method, to get a spectral approach of the solution of the system of partial differential equations associated to the model in transient state.

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This work deals with the numerical simulation of air stripping process for the pre-treatment of groundwater used in human consumption. The model established in steady state presents an exponential solution that is used, together with the Tau Method, to get a spectral approach of the solution of the system of partial differential equations associated to the model in transient state.