932 resultados para Tecnologia de acesso aberto
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The natural and anthropogenic changes that are occurring at the coastal zone around the world represent the greatest problem to society in this century. This problem becomes more evident due to high density of coastal cities, to growing tourist-estate speculation of those areas and to climate change that tend to trigger and accelerate the erosive processes that operating in the littoral. In this context, it‟s possible perceive ever more a significant increase of problems associated to the coastal erosion and retreat of cliffs in the state of Rio Grande do Norte, where this study area of this search is located. The area is located in the coastal zone of the city of Baía Formosa/RN, in south-eastern coast of Rio Grande do Norte, and has a extension of about 1200 meters along the Porto beach. The main objective of this study is to analyze the stability of these cliffs in this region. Through field investigations, testings and computational analysis using the Finite Element Method and Equilibrium Limit Methods. The area was divided into four sections, and were applied checklists, and also realized characterization tests and direct shear tests with materials obtained along these sections. In this manner, it was found that the segments of cliff in this coastal zone have heights around 4 meters to 14 meters and inclinations of approximately 40° to 90°.However the constituents soils of the cliffs were classified, in general terms in accordance to Unified Soil Classification System (USCS), as clayey sands or silty sands, clays of low plasticity, clayey gravels and poorly graduaded sands. The most variegated and clayey soils belong to base of the cliff. The stability analysis showed that the safety factors ranged in section 01, from 1.92 to 4.93, in the section 02, from 1.00 to 1.43, in the section 03, from 1.36 to 1.75 , and section 04, from 1.00 to 3.64. Thus, the sections 02 and 03 were considered more unstable. However, the section 03 can be considered as the most critical section due to the absence of coastal protection structures and the narrow strip of beach.
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The piles are one of the most important types of solution adopted for the foundation of buildings. They are responsible for transmitting to the soil in deepe r and resistant layers loads from structures. The interaction of the foundation element with the soil is a very important variable, making indispensable your domain in order to determine the strength of the assembly and establish design criteria for each c ase of application of the pile. In this research analyzes were performed f rom experiments load tests for precast concrete piles and inve stigations of soil of type SPT, a study was performed for obtaining the ultimate load capacity of the foundation through methods extrapolation of load - settlement curve , semi - empirical and theoretic . After that, were realized comparisons between the different methods used for two types of soil a granular behavior and other cohesive. For obtaining soil paramet ers to be used i n the methods were established empirical correlations with the standard penetration number (NSPT). The charge - settlement curves of the piles are also analyzed. In the face of established comparisons was indicated the most reliable semiempirical method Déco urt - Quaresma as the most reliable for estimating the tensile strength for granular and cohesive soils. Meanwhile, among the methods studied extrapolation is recommended method of Van der Veen as the most appropriate for predicting the tensile strength.
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Planejar o espaço urbano pensando na inclusão social de pessoas com deficiência significa considerar a acessibilidade como fator essencial para uma mobilidade urbana completa e segura. Esse ideal reflete-se no espaço comercial que, para ser convidativo e livre de barreiras (sejam elas físicas, tecnológicas ou atitudinais), precisa promover o direito de livre acesso a todos os cidadãos. Partindo deste entendimento, esse estudo tem como objetivo geral analisar as condições de acessibilidade da região denominada “Coração do Alecrim”, área de tradicional comércio popular em Natal. A pesquisa recorreu à abordagem multimétodos e aconteceu em três momentos: (i) avaliação técnica da área por meio da aplicação de check-list, elaborado com base na legislação específica e validado por painel de experts; (ii) elaboração de mapas com uso de Sistema de Informação Geográfica (S.I.G.), tendo como base o resultado da análise realizada na primeira etapa; (iii) aplicação de questionários e realização de entrevistas informais com usuários (visitantes, proprietários e comerciários), para coletar dados sobre sua percepção sobre o lugar, complementando a análise técnica efetuada. Resumindo as informações coletadas, foram elaboradas matrizes de descobertas, como uma junção de todas as etapas de análise. Na conclusão são apresentados pontos críticos de acessibilidade (detectados pela pesquisadora ou apontados pelos usuários) e indicadas algumas diretrizes para a intervenção no local, de modo a colaborar para futuros processos de planejamento urbano do bairro do Alecrim.
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This work analyses the effects of form over the emergence of new patterns of use and occupation in public spaces of housing estates designed in the 1980s and 1990s in Natal’s municipality (Brazil). We start from the premise that form acts on social process (HILLIER; HANSON, 1984), and verify how much the original spatial configuration of Parque Serrambi housing states contributed to the creation of new spatial patterns following the interventions of the people living there. The Serrambi states were built in Natal’s south based on an urbanization model following modernist’s principals and aimed to supply demands for popular dwellings. They were one of the last estates financed by the former National Dwelling Bank (BNH) and supervised by the Dwelling Cooperatives Orientation Institute (INOCOOP), materialized a spatial form different from the highrise dwelling experiences from the same period. The results were obtained through configurational analysis based on Space Syntax conceptual and methodological framework, in which space and society are viewed as interrelated. The analyses was based on represanting and quantifying spatial properties and identificatying social patterns related to the interventions. We identified that the original spatial configurations, associated to subtle changes in the states social patterns, analysed independently of non-morphological categories, gave way to the occupation patterns verrified in both Serrambi cases.
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The chaotic behavior has been widely observed in nature, from physical and chemical phenomena to biological systems, present in many engineering applications and found in both simple mechanical oscillators and advanced communication systems. With regard to mechanical systems, the effects of nonlinearities on the dynamic behavior of the system are often of undesirable character, which has motivated the development of compensation strategies. However, it has been recently found that there are situations in which the richness of nonlinear dynamics becomes attractive. Due to their parametric sensitivity, chaotic systems can suffer considerable changes by small variations on the value of their parameters, which is extremely favorable when we want to give greater flexibility to the controlled system. Hence, we analyze in this work the parametric sensitivity of Duffing oscillator, in particular its unstable periodic orbits and Poincar´e section due to changes in nominal value of the parameter that multiplies the cubic term. Since the amount of energy needed to stabilize Unstable Periodic Orbits is minimum, we analyze the control action needed to control and stabilize such orbits which belong to different versions of the Duffing oscillator. For that we will use a smoothed sliding mode controller with an adaptive compensation term based on Fourier series.
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With the intention of studying and developing the design process based on a specific methodology, the object of this work is to present the design of a gated condominium community in Natal based on the application of principles of shape grammar, used in their design process. The shape grammar is a design method developed in the 1970s by George Stiny and James Gips. It is used for the analysis of the project as well as for its synthesis, with the goal of creating a "formal vocabulary" through mathematical and/or geometrical operations. Here, the methodology was used in the synthesis of the design process, through the relationship between formal subtractions and the houses’ architectural planning. As a result, five dwellings configurations were proposed, each one different from the other with respect to their shape and architectural programming, distributed in three twin groups, which are repeated until the final total of nine architectural volumes. In addition to studies of the condominium’s ventilation and the buildings’ shading simulations, studies of spatial flexibility and acoustic performance were also performed. The mapping of the design process, one of the specific objectives of the dissertation, was composed not only by the record of formal constraints (the preparation and application of rules), but also by physical, environmental, legal and sustainability aspects in relation to, on one hand, the optimization of the shading and passive ventilation for hot and humid climates, and, on the other hand, the modulation and rationalization of the construction.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
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Software product line engineering promotes large software reuse by developing a system family that shares a set of developed core features, and enables the selection and customization of a set of variabilities that distinguish each software product family from the others. In order to address the time-to-market, the software industry has been using the clone-and-own technique to create and manage new software products or product lines. Despite its advantages, the clone-and-own approach brings several difficulties for the evolution and reconciliation of the software product lines, especially because of the code conflicts generated by the simultaneous evolution of the original software product line, called Source, and its cloned products, called Target. This thesis proposes an approach to evolve and reconcile cloned products based on mining software repositories and code conflict analysis techniques. The approach provides support to the identification of different kinds of code conflicts – lexical, structural and semantics – that can occur during development task integration – bug correction, enhancements and new use cases – from the original evolved software product line to the cloned product line. We have also conducted an empirical study of characterization of the code conflicts produced during the evolution and merging of two large-scale web information system product lines. The results of our study demonstrate the approach potential to automatically or semi-automatically solve several existing code conflicts thus contributing to reduce the complexity and costs of the reconciliation of cloned software product lines.
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Técnicas de otimização conhecidas como as metaheurísticas tem conseguido resolversatisfatoriamente problemas conhecidos, mas desenvolvimento das metaheurísticas écaracterizado por escolha de parâmetros para sua execução, na qual a opção apropriadadestes parâmetros (valores). Onde o ajuste de parâmetro é essencial testa-se os parâmetrosaté que resultados viáveis sejam obtidos, normalmente feita pelo desenvolvedor que estaimplementando a metaheuristica. A qualidade dos resultados de uma instância1 de testenão será transferida para outras instâncias a serem testadas e seu feedback pode requererum processo lento de “tentativa e erro” onde o algoritmo têm que ser ajustado para umaaplicação especifica. Diante deste contexto das metaheurísticas surgiu a Busca Reativaque defende a integração entre o aprendizado de máquina dentro de buscas heurísticaspara solucionar problemas de otimização complexos. A partir da integração que a BuscaReativa propõe entre o aprendizado de máquina e as metaheurísticas, surgiu a ideia dese colocar a Aprendizagem por Reforço mais especificamente o algoritmo Q-learning deforma reativa, para selecionar qual busca local é a mais indicada em determinado instanteda busca, para suceder uma outra busca local que não pode mais melhorar a soluçãocorrente na metaheurística VNS. Assim, neste trabalho propomos uma implementação reativa,utilizando aprendizado por reforço para o auto-tuning do algoritmo implementado,aplicado ao problema do caixeiro viajante simétrico e ao problema escalonamento sondaspara manutenção de poços.
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This work has the main objective to obtain nano and microcrystals of cellulose, extracted from the pineapple leaf fibres (PALF), as reinforcement for the manufacture of biocomposite films with polymeric matrices of Poly(vinyl alcohol) (PVA) and Poly(lactic acid) (PLA). The polymer matrices and the nano and microcrystals of cellulose were characterised by means of TGA, FTIR and DSC. The analysis was performed on the pineapple leaves to identify the macro and micronutrients. The fibers of the leaves of the pineapple were extracted in a desfibradeira mechanical. The PALF extracted were washed to remove washable impurities and subsequently treated with sodium hydroxide (NaOH) and sodium hypochlorite (NaClO) in the removal of impurities, such as fat, grease, pectates, pectin and lignin. The processed PALF fibers were hydrolysed in sulfuric acid (H2SO4) at a concentration of 13.5 %, to obtain nano and microcrystals of cellulose. In the manufacture of biocomposite films, concentrations of cellulose, 0 %, 1 %, 3 %, 6 %, 9% and 12% were used as reinforcement to the matrices of PVA and PLA. The PVA was dissolved in distilled water at 80 ± 5 oC and the PLA was dissolved in dichloromethane at room temperature. The manufacture of biocompósitos in the form of films was carried out by "casting". Tests were carried out to study the water absorption by the films and mechanical test of resistance to traction according to ASTM D638-10 with a velocity of 50 mm/min.. Chi-square statistical test was used to check for the existence of significant differences in the level of 0.05: the lengths of the PALF, lengths of the nano and microcrystals of cellulose and the procedures used for the filtration using filter syringe of 0.2 μm or filtration and centrifugation. The hydrophilicity of biocompósitos was analysed by measuring the contact angle and the thickness of biocompósitos were compared as well as the results of tests of traction. Statistical T test - Student was also applied with the significance level (0.05). In biodegradation, Sturm test of standard D5209 was used. Nano and microcrystals of cellulose with lengths ranging from 7.33 nm to 186.17 nm were found. The PVA films showed average thicknesses of 0.153 μm and PLA 0.210 μm. There is a strong linear correlation directly proportional between the traction of the films of PVA and the concentration of cellulose in the films (composite) (0,7336), while the thickness of the film was correlated in 0.1404. Nano and microcrystals of cellulose and thickness together, correlated to 0.8740. While the correlation between the cellulose content and tensile strength was weak and inversely proportional (- 0,0057) and thickness in -0.2602, totaling -0,2659 in PLA films. This can be attributed to the nano and microcrystals of cellulose not fully adsorbed to the PLA matrix. In the comparison of the results of the traction of the two polymer matrices, the nano and microcrystals have helped in reducing the traction of the films (composite) of PLA. There was still the degradation of the film of PVA, within a period of 20 days, which was not seen in the PLA film, on the other hand, the observations made in the literature, the average time to start the degradation is above 60 days. What can be said that the films are biodegradable composites, with hydrophilicity and the nano and microcrystals of cellulose, contribute positively in the improvement of the results of polymer matrices used.
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Biodegradable microspheres used as controlled release systems are important in pharmaceutics. Chitosan biopolymer represents an attractive biomaterial alternative because of its physicochemical and biological characteristics. Chitosan microspheres are expected to become promising carrier systems for drug and vaccine delivery, especially for non-invasive ways oral, mucosal and transdermal routes. Controlling the swelling rate and swelling capacity of the hydrogel and improving the fragile nature of microspheres under acidic conditions are the key challenges that need to be overcomed in order to enable the exploration of the full pharmaceutical potential use of these microparticles. Many studies have focused on the modification of chitosan microsphere structures with cross-linkers, various polymers blends and new organic-inorganic hybrid systems in order to obtain improved properties. In this work, microspheres made of chitosan and nanosized hydrophobic silica (Aerosil R972) were produced by a method consisting of two steps. First, a preparation of a macroscopically homogeneous chitosan-hydrophobic silica dispersion was prepared followed by spray drying. FTIR spectroscopy, X-ray powder diffraction, differential scanning calorimetry, thermal gravimetric analysis, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (TEM) were used to characterize the microspheres. Also, the were conducted acid stability, moisture sorption capacity, release properties and biological assays. The chitosan-hydrophobic silica composite microspheres showed improved thermal degradation, lower water affinity, better acid stability and ability to retard rifampicin and propranolol hydrochloride (drug models) release under simulated physiological conditions. In vitro biocompatibility studies indicated low cytotoxicity and low capacity to activate cell production of the pro-inflammatory mediator nitric oxide. The results show here encourage further studies on the use of the new chitosan-hydrophobic silica composite microspheres as drug carrier systems via oral or nasal routes.
Otimização da síntese do AlSBA-15 para produção de biodiesel por transesteri-ficação do óleo de coco
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Stimulus encouraging the production and consumption of biodiesel favors the policy of pre-serving the environment, contributing to the reduction of greenhouse gas reducing climate change. The current trend of research in this field focuses on improving these processes with the use of heterogeneous catalysts, seeing has significant advantages such as: low contamination of products, ease of separation of the catalyst from the reaction medium, possibili-ty of reuse of the catalyst, decreased corrosion problems. The objective of this research was to optimize the synthesis of AlSBA-15 for the production of biodiesel through transesterification process via ethyl route. For the optimization of hydrothermal synthesis of type AlSBA-15 catalyst has assembled a 23 factorial experimental matrix with eleven trials. The stoichiometric amounts of starting materials were varied according to different ratios Si / Al which is a factor in the experimental design, in addition to the time and temperature of aging of the synthesis gel. The material showed the best results of characterization (SBET = 591.7 (m2 / g), Vp = 0.83 (cm3 / g), Dp = 5.59 (nm), w = 6.48 (nm) was synthesized at 100 ° C for 24 hours, with a ratio Si / Al = 10.This material was applied as a heterogeneous catalyst in the reaction of ethyl transesterification as raw coconut oil in natura. Coconut oil presented suitable for obtaining biodiesel via ethyl route.The visual aspects and physical-chemical characteristics of the reaction products show that AlSBA-15 catalyst favored the reaction. According to physical-chemical analysis the order of oxidative stability of the product of the transesterification reaction was: catalytic reaction at 1500 ° C> non-catalytic reaction at 100 ° C> 100 ° C catalytic> catalytic reaction at 200 ° C Reaction. The results of oxidative stability and kinematic viscosity shows that the biodiesel produced in the catalytic sandblasting held at 150 ° C which was maintained within the ABNT NBR 7148, ABNT NBR 10441 and EN 14112.
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Porous structures are being widely investigated for use in biomedical implants, aiming to mechanically integrate and functionally the implant inside the bone tissue. Moreover, this structure is also important for drugs that can be stored and can induce and accelerate the process of osseointegration. With the purpose to investigate this effect, Ti, Nb and Sn metal powders, were sintered by plasma using a hollow cathode discharge. Sintering was performed in argon plasma set at 4 mbar pressure and temperatures of 500 ° C, 600 ° C and 700 ° C. Samples were also sintered in the electrical resistance furnace at 1200 ° C in order to compare plasma sintering with the conventional method. It was observed that plasma samples sintered with the hollow cathode configuration showed a gradient in porosity, while the samples sintered in the resistive furnace did not. Furthermore, differences in the microstructure of the samples were found, were a surface with higher porosity and ales porous core were obtained at different temperatures. The percolation profile of distilled water and the chemical compositions of the porous layers of the plasma treated samples were the main results obtained. Based on these results, we can conclude that this structure is particularly important for application in the biomedical field such as scaffolds for drug delivery and implants
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In this work evaluate the technical characteristics of the fibers grown in settlements Guamaré, colored cotton seeds were donated existing in the Germplasm Bank of Embrapa Cotton. We sought through the breeding program, raising the resistance, fineness, length and uniformity of cotton fibers, as well as stabilize the staining of fibers in the BRS Topaz, BRS Brown and BRS Green shades and raise their productivity in the field. First, the individual selections to test progeny seeds, and thereafter the hybridization method followed by family selection to obtain variations in the color tones were performed. The BRS Topaz, BRS Brown and BRS Green varieties were produced, analyzed and compared with existing cottons in the region which is the White cotton. The properties amount of impurities and neps, length, length uniformity, short fiber content, fineness and tensile strength of the fibers were sized in Classifiber, NATI, Pressley and Micronaire devices. 10 trials each with 10 tests for all four fiber types were carried out. The White and Topaz fibers showed greater length (32-34mm) and greater resistance (7.94 lb/mg and 7.97 lb/mg respectively) and showed finesse with lower micronaire index 3,71μg/inch and 3, 73μg/inch and a low rate of short fibers. The results were very promising for the use of genetically improved cotton in the manufacturing of fabric and yarn in the textile industry. The fibers were brown colored cotton used in the manufacture of a composite fiber with thermoplastic resin
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The Monte Carlo method is accurate and is relatively simple to implement for the solution of problems involving complex geometries and anisotropic scattering of radiation as compared with other numerical techniques. In addition, differently of what happens for most of numerical techniques, for which the associated simulations computational time tends to increase exponentially with the complexity of the problems, in the Monte Carlo the increase of the computational time tends to be linear. Nevertheless, the Monte Carlo solution is highly computer time consuming for most of the interest problems. The Multispectral Energy Bundle model allows the reduction of the computational time associated to the Monte Carlo solution. The referred model is here analyzed for applications in media constituted for nonparticipating species and water vapor, which is an important emitting species formed during the combustion of hydrocarbon fuels. Aspects related to computer time optimization are investigated the model solutions are compared with benchmark line-by-line solutions