70 resultados para Foc
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Numerous researchers have studied about nonlinear dynamics in several areas of science and engineering. However, in most cases, these concepts have been explored mainly from the standpoint of analytical and computational methods involving integer order calculus (IOC). In this paper we have examined the dynamic behavior of an elastic wide plate induced by two electromagnets of a point of view of the fractional order calculus (FOC). The primary focus of this study is on to help gain a better understanding of nonlinear dynamic in fractional order systems. © 2011 American Institute of Physics.
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This paper deals with a system involving a flexible rod subjected to magnetic forces that can bend it while simultaneously subjected to external excitations produces complex and nonlinear dynamic behavior, which may present different types of solutions for its different movement-related responses. This fact motivated us to analyze such a mechanical system based on modeling and numerical simulation involving both, integer order calculus (IOC) and fractional order calculus (FOC) approaches. The time responses, pseudo phase portraits and Fourier spectra have been presented. The results obtained can be used as a source for conduct experiments in order to obtain more realistic and more accurate results about fractional-order models when compared to the integer-order models. © Published under licence by IOP Publishing Ltd.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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No decorrer das últimas décadas, o estudo das Relações Internacionais diversificou sua análise, deixando de ter um enfoque direcionado sobre a atuação dos Estados nacionais e passando a analisar mais atentamente a dinâmica e ascensão de novos atores no cenário internacional, como as entidades subnacionais, incluindo as cidades e os governos locais, gerando um novo foco de análise, principalmente no contexto da cooperação internacional. A presente dissertação analisa por quais razões e de que maneira ocorre a inserção e atuação internacional das cidades amazônicas de Belém e Manaus, tendo como cenário um Mundo globalizado e interdependente. No conjunto desse novo cenário, favorável às relações internacionais, a Cooperação Internacional passa a ser um instrumento latente para o desenvolvimento não somente dos países, mas também das cidades, através da Cooperação Descentralizada; fenômeno político-econômico relativamente recente e que vem adentrando cada vez mais as agendas de desenvolvimento local. As cidades cada vez mais passam a adotar as relações internacionais, tal como estratégias de cooperação descentralizada como uma agenda propulsora e paralela de desenvolvimento, seja na captação de recursos externos,seja no fortalecimento da identidade local, na promoção do comércio exterior ou, até mesmo na disseminação cultural. Belém e Manaus, lócus desta pesquisa, apresentaram ao longo dos anos diversas motivações e formas de efetivarem suas relações internacionais e, para tal análise, adotou-se uma análise fundamentalmente qualitativa, traçando um quadro analíticodescritivo entre as cidades investigadas. O presente trabalho analisa as ações, estratégias, mecanismos e forma institucionalizada ou não de gerir as atividades internacionais das referidas cidades. O cenário global atual é incentivador das interações multiníveis entre velhos e novos atores internacionais, todavia o habitus das relações -internacionais incita cada vez mais a continuidade e o compromisso que os Governos (sejam eles nacionais ou locais) devem ter para corresponder e acompanhar as dinâmicas impostas pela globalização,embora, nem todos os Governos acompanham, possuem ou dedicam estruturas adequadas aos anseios que o novo e interdependente cenário internacional exige.
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Pós-graduação em Agronomia (Proteção de Plantas) - FCA
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Introduction 1.1 Occurrence of polycyclic aromatic hydrocarbons (PAH) in the environment Worldwide industrial and agricultural developments have released a large number of natural and synthetic hazardous compounds into the environment due to careless waste disposal, illegal waste dumping and accidental spills. As a result, there are numerous sites in the world that require cleanup of soils and groundwater. Polycyclic aromatic hydrocarbons (PAHs) are one of the major groups of these contaminants (Da Silva et al., 2003). PAHs constitute a diverse class of organic compounds consisting of two or more aromatic rings with various structural configurations (Prabhu and Phale, 2003). Being a derivative of benzene, PAHs are thermodynamically stable. In addition, these chemicals tend to adhere to particle surfaces, such as soils, because of their low water solubility and strong hydrophobicity, and this results in greater persistence under natural conditions. This persistence coupled with their potential carcinogenicity makes PAHs problematic environmental contaminants (Cerniglia, 1992; Sutherland, 1992). PAHs are widely found in high concentrations at many industrial sites, particularly those associated with petroleum, gas production and wood preserving industries (Wilson and Jones, 1993). 1.2 Remediation technologies Conventional techniques used for the remediation of soil polluted with organic contaminants include excavation of the contaminated soil and disposal to a landfill or capping - containment - of the contaminated areas of a site. These methods have some drawbacks. The first method simply moves the contamination elsewhere and may create significant risks in the excavation, handling and transport of hazardous material. Additionally, it is very difficult and increasingly expensive to find new landfill sites for the final disposal of the material. The cap and containment method is only an interim solution since the contamination remains on site, requiring monitoring and maintenance of the isolation barriers long into the future, with all the associated costs and potential liability. A better approach than these traditional methods is to completely destroy the pollutants, if possible, or transform them into harmless substances. Some technologies that have been used are high-temperature incineration and various types of chemical decomposition (for example, base-catalyzed dechlorination, UV oxidation). However, these methods have significant disadvantages, principally their technological complexity, high cost , and the lack of public acceptance. Bioremediation, on the contrast, is a promising option for the complete removal and destruction of contaminants. 1.3 Bioremediation of PAH contaminated soil & groundwater Bioremediation is the use of living organisms, primarily microorganisms, to degrade or detoxify hazardous wastes into harmless substances such as carbon dioxide, water and cell biomass Most PAHs are biodegradable unter natural conditions (Da Silva et al., 2003; Meysami and Baheri, 2003) and bioremediation for cleanup of PAH wastes has been extensively studied at both laboratory and commercial levels- It has been implemented at a number of contaminated sites, including the cleanup of the Exxon Valdez oil spill in Prince William Sound, Alaska in 1989, the Mega Borg spill off the Texas coast in 1990 and the Burgan Oil Field, Kuwait in 1994 (Purwaningsih, 2002). Different strategies for PAH bioremediation, such as in situ , ex situ or on site bioremediation were developed in recent years. In situ bioremediation is a technique that is applied to soil and groundwater at the site without removing the contaminated soil or groundwater, based on the provision of optimum conditions for microbiological contaminant breakdown.. Ex situ bioremediation of PAHs, on the other hand, is a technique applied to soil and groundwater which has been removed from the site via excavation (soil) or pumping (water). Hazardous contaminants are converted in controlled bioreactors into harmless compounds in an efficient manner. 1.4 Bioavailability of PAH in the subsurface Frequently, PAH contamination in the environment is occurs as contaminants that are sorbed onto soilparticles rather than in phase (NAPL, non aqueous phase liquids). It is known that the biodegradation rate of most PAHs sorbed onto soil is far lower than rates measured in solution cultures of microorganisms with pure solid pollutants (Alexander and Scow, 1989; Hamaker, 1972). It is generally believed that only that fraction of PAHs dissolved in the solution can be metabolized by microorganisms in soil. The amount of contaminant that can be readily taken up and degraded by microorganisms is defined as bioavailability (Bosma et al., 1997; Maier, 2000). Two phenomena have been suggested to cause the low bioavailability of PAHs in soil (Danielsson, 2000). The first one is strong adsorption of the contaminants to the soil constituents which then leads to very slow release rates of contaminants to the aqueous phase. Sorption is often well correlated with soil organic matter content (Means, 1980) and significantly reduces biodegradation (Manilal and Alexander, 1991). The second phenomenon is slow mass transfer of pollutants, such as pore diffusion in the soil aggregates or diffusion in the organic matter in the soil. The complex set of these physical, chemical and biological processes is schematically illustrated in Figure 1. As shown in Figure 1, biodegradation processes are taking place in the soil solution while diffusion processes occur in the narrow pores in and between soil aggregates (Danielsson, 2000). Seemingly contradictory studies can be found in the literature that indicate the rate and final extent of metabolism may be either lower or higher for sorbed PAHs by soil than those for pure PAHs (Van Loosdrecht et al., 1990). These contrasting results demonstrate that the bioavailability of organic contaminants sorbed onto soil is far from being well understood. Besides bioavailability, there are several other factors influencing the rate and extent of biodegradation of PAHs in soil including microbial population characteristics, physical and chemical properties of PAHs and environmental factors (temperature, moisture, pH, degree of contamination). Figure 1: Schematic diagram showing possible rate-limiting processes during bioremediation of hydrophobic organic contaminants in a contaminated soil-water system (not to scale) (Danielsson, 2000). 1.5 Increasing the bioavailability of PAH in soil Attempts to improve the biodegradation of PAHs in soil by increasing their bioavailability include the use of surfactants , solvents or solubility enhancers.. However, introduction of synthetic surfactant may result in the addition of one more pollutant. (Wang and Brusseau, 1993).A study conducted by Mulder et al. showed that the introduction of hydropropyl-ß-cyclodextrin (HPCD), a well-known PAH solubility enhancer, significantly increased the solubilization of PAHs although it did not improve the biodegradation rate of PAHs (Mulder et al., 1998), indicating that further research is required in order to develop a feasible and efficient remediation method. Enhancing the extent of PAHs mass transfer from the soil phase to the liquid might prove an efficient and environmentally low-risk alternative way of addressing the problem of slow PAH biodegradation in soil.
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Nell’ambito della presente tesi verrà descritto un approccio generalizzato per il controllo delle macchine elettriche trifasi; la prima parte è incentrata nello sviluppo di una metodologia di modellizzazione generale, ossia in grado di descrivere, da un punto di vista matematico, il comportamento di una generica macchina elettrica, che possa quindi includere in sé stessa tutte le caratteristiche salienti che possano caratterizzare ogni specifica tipologia di macchina elettrica. Il passo successivo è quello di realizzare un algoritmo di controllo per macchine elettriche che si poggi sulla teoria generalizzata e che utilizzi per il proprio funzionamento quelle grandezze offerte dal modello unico delle macchine elettriche. La tipologia di controllo che è stata utilizzata è quella che comunemente viene definita come controllo ad orientamento di campo (FOC), per la quale sono stati individuati degli accorgimenti atti a migliorarne le prestazioni dinamiche e di controllo della coppia erogata. Per concludere verrà presentata una serie di prove sperimentali con lo scopo di mettere in risalto alcuni aspetti cruciali nel controllo delle macchine elettriche mediante un algoritmo ad orientamento di campo e soprattutto di verificare l’attendibilità dell’approccio generalizzato alle macchine elettriche trifasi. I risultati sperimentali confermano quindi l’applicabilità del metodo a diverse tipologie di macchine (asincrone e sincrone) e sono stati verificate nelle condizioni operative più critiche: bassa velocità, alta velocità bassi carichi, dinamica lenta e dinamica veloce.
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Intracerebral hemorrhage (ICH), for which no effective treatment strategy is currently available, constitutes one of the most devastating forms of stroke. As a result, developing therapeutic options for ICH is of great interest to the medical community. The 3 potential therapies that have the most promise are cell replacement therapy, enhancing endogenous repair mechanisms, and utilizing various neuroprotective drugs. Replacement of damaged cells and restoration of function can be accomplished by transplantation of cells derived from different sources, such as embryonic or somatic stem cells, umbilical cord blood, and genetically modified cell lines. Early experimental data showing the benefits of cell transplantation on functional recovery after ICH have been promising. Nevertheless, several studies have focused on another therapeutic avenue, investigating novel ways to activate and direct endogenous repair mechanisms in the central nervous system, through exposure to specific neuronal growth factors or by inactivating inhibitory molecules. Lastly, neuroprotective drugs may offer an additional tool for improving neuronal survival in the perihematomal area. However, a number of scientific issues must be addressed before these experimental techniques can be translated into clinical therapy. In this review, the authors outline the recent advances in the basic science of treatment strategies for ICH.
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Hay un ejemplar encuadernado con: La Real Compañia formada por S.M. para llevar a efecto el canal de navegación y riego del reyno de Murcia, las... experiencias de que informa D. Domingo Aguirre... le han confirmado en los abusos y fraudes que hacen muchos... (XVIII/4279).
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Hay un ejemplar encuadernado con: La Real Compañia formada por S.M. para llevar a efecto el canal de navegación y riego del reyno de Murcia, las... experiencias de que informa D. Domingo Aguirre... le han confirmado en los abusos y fraudes que hacen muchos... (XVIII/4279).
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Provision fechada en Madrid el 21 de mayo de 1744
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Hay un ejemplar encuadernado con: Pragmatica que su Magestad ha mandado promulgar revalidando los anteriores en qu ese prohibe el uso de armas blancas cortas y las de fuego ... (XVIII/4280).
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Trata-se da meta-avaliação de um processo avaliativo desenvolvido por secretários e assessores técnicos municipais de uma região de saúde do estado de São Paulo, com foco nos critérios de utilidade e participação. É uma pesquisa qualitativa, cuja base empírica foi 1) o material produzido em sete oficinas realizadas com os representantes municipais, com vistas à avaliação de um aspecto da linha de cuidados em saúde sob a ótica da integralidade; e 2) as entrevistas semiestruturadas realizadas com os mesmos atores após a finalização do processo avaliativo. Para a avaliação do critério de utilidade, utilizou-se principalmente o referencial de KIRKHART (2000), com o objetivo de ampliar a análise para além do uso instrumental dos achados avaliativos e focá-la na identificação de influências múltiplas exercidas por um fenômeno complexo como um processo avaliativo. A análise do critério participação se deu com base no referencial de COUSINS e WHITMORE (1998), buscando a identificação no material empírico de decisões ou aspectos contextuais que fizeram com que a opção participativa fosse aprofundada ou limitada no processo em foco. O trabalho destaca a importância de explicitar pressupostos que baseiam a metodologia da avaliação/ meta-avaliação escolhida, e a necessidade de se buscar referenciais teóricos de análise compatíveis com a opção realizada, frisando a inexistência de posturas neutras ou estudos totalmente objetivos; e a importância de capacitar avaliadores a acompanharem a demanda dos participantes de um processo participativo com a flexibilidade necessária para conferir-lhe o maior aproveitamento possível. Conclui-se pela viabilidade, com vantagens, da realização de processos participativos locais com gestores na Saúde Pública, destacando a possibilidade de ganhos em formação e o enriquecimento dos processos de negociação em nível do território, de forma coerente à política de construção das regiões de saúde no SUS.