Protótipo de uma unidade com tri-geração de energia para utilizações remotas: aplicação de módulo secondutivo gerador termoelétrico

The generation for termoeletricity is characterized as a solid process of conversion of thermal energy (heat) in electric without the necessity of mobile parts. Although the conversion process is of low efficiency the system presents high degree of trustworthiness and low requisite of maintenance and durability. Its principle is based on the studies of termogeneration carried through by Thomas Seebeck in 1800. The frank development of the technologies of solid state for termoeletricity generation, the necessity of the best exploitation of the energy, also with incentive the cogeneration processes, the reduction of the ambient impact allies to the development of modules semiconductors of high efficiency, converge to the use of the thermoeletric generation through components of solid state in remote applications. The work presents the development, construction and performance evaluation of an prototype, in pilot scale, for energy tri-generation aiming at application in remote areas. The unit is composed of a gas lamp as primary source of energy, a module commercial semiconductor for thermoelectric generation and a shirt for production of the luminosity. The project of the device made compatible a headstock for adaptation in the gas lamp, a hot source for adaptation of the module, an exchanger of to be used heat as cold source and to compose first stage of cogeneration, an exchanger of tubular heat to compose second stage of cogeneration, the elaboration of a converter dc-dc type push pull, adequacy of a system of acquisition of temperature. It was become fullfilled assembly of the prototype in group of benches for tests and assay in the full load condition in order to evaluate its efficiency, had been carried through energy balance of the unit. The prototype presented an electric efficiency of 0,73%, thermal of 56,55%, illumination of 1,35% and global of 58,62%. The developed prototype, as the adopted methodology of assay had also taken care of to the considered objectives, making possible the attainment of conclusive results concerning to the experiment. Optimization in the system of setting of the semicondutor module, improvement in the thermal insulation and design of the prototype and system of protection to the user are suggestions to become it a commercial product

Estudo das propriedades mecânicas de biocompósitos de polipropileno reforçados com fibras naturais

This research presents an approach to the addition of curauá fibers and licuri fibers in a polypropylene resin matrix, such as an alternative proposal to reinforce the polymeric composites. Fiber content of 0 %, 5 %, 10 %, and 20% were analyzed for verification of their mechanical properties comparing them, inclusive with the properties of polypropylene. The grainulated biocomposites had been prepared in an extrusora. The test bodies had been molded by injection and submitted to the mechanical essays uniaxial traction, flexion on three points, impact, in addition to thermal tests (HDT). These biocomposites had been also subjected the essay physicist-chemistry index of fluidity (IF). It was observed that the biocomposites of PP with 20% curauá, obtained bigger increase in the modulus of elasticity and a bigger reduction in the resistance to the impact. In the mechanical behavior, for all the biocomposites, these were increases in values of the limit of drainage and tension of rupture, when tested by uniaxial traction, as they added the fibers. Another important point was the increase of the resistance the flexion. It was also noted that the addition of fibers reduced the thermal degradation of the mixture natural fibers / polypropylene.

Previsão do módulo de elasticidade transversal de compósitos unidirecionais através de redes neurais mistas

The aim of this study is to create an artificial neural network (ANN) capable of modeling the transverse elasticity modulus (E2) of unidirectional composites. To that end, we used a dataset divided into two parts, one for training and the other for ANN testing. Three types of architectures from different networks were developed, one with only two inputs, one with three inputs and the third with mixed architecture combining an ANN with a model developed by Halpin-Tsai. After algorithm training, the results demonstrate that the use of ANNs is quite promising, given that when they were compared with those of the Halpín-Tsai mathematical model, higher correlation coefficient values and lower root mean square values were observed

Morfologia e propriedades mecânicas da fibra de sisal unidirecional e em sobreposição de compósito com resina epóxi

The composites manufactured with long fibres aligned in a single direction, and overlay has been shown to have better performance than the short fibers randomly distributed. In particular, the lignocellulosic fibers extracted from the sisal leaves, used in conjunction with the epoxy resin has attracted the attention of many researchers because the final properties of the system formed. In this work composites based on epoxy resin reinforced with sisal fibers were manufactured. The sisal fibres were treated with an alkaline solution of 0.06 mol/l NaOH. The treated, and untreated fibres were subjected to tension x extension tests. The composites were manufactured in the "Lossy" mold with the specifications of the samples to be produced (300x20x4 mm). The tension tests were carried out in accordance with the ASTM standards 3039 (for the composite aligned in a single direction) and ASTM D5573 (for composites in overlay), three point bending tests were performed according to ASTM D790. Analyzing the results of the tests of tension and three point bending tests, it was observed that the composites with the configuration of overlapping had the better elastic module in both tests. As to the maximum resistance to tension, the best result was the composites aligned in a single direction. Tests of absorption of water and micrographs are in progress

Tubulações de PRFV com adição de areia quartzosa visando sua aplicação na indústria do petróleo

Fillers are often added in composites to enhance performance and/or to reduce cost. Fiberglass pipes must meet performance requirements and industrial sand is frequently added for the pipe to be cost competitive. The sand is added to increase pipe wall thickness, thus increase pipe stiffness. The main goal of the present work is to conduct an experimental investigation between pipes fabricated with and without de addition of sand, to be used in the petroleum industry. Pipes were built using E-glass fibers, polyester resin and siliceous sand. The fabrication process used hand lay up and filament winding and was divided in two different parts: the liner and the structural wall. All tested pipes had the same liner, but different structural wall composition, which is the layer where siliceous sand may be added or not. The comparative investigation was developed considering the results of longitudinal tensile tests, hoop tensile tests, hydrostatic pressure leak tests and parallel-plate loading stiffness tests. SEM was used to analyze if the sand caused any damage to the glass fibers, during the fabrication process, because of the fiber-sand contact. The procedure was also used to verify the composite conditions after the hydrostatic pressure leak test. The results proved that the addition of siliceous sand reduced the leak pressure in about 17 %. In the other hand, this loss in pressure was compensated by a stiffness increment of more than 380 %. MEV analyses show that it is possible to find damage on the fiber-sand contact, but on a very small amount. On most cases, the contact occurs without damage evidences. In summary, the addition of sand filler represented a 27.8 % of cost reduction, when compared to a pipe designed with glass fiber and resin only. This cost reduction combined to the good mechanical tests results make siliceous sand filler suitable for fiberglass pressure pipes

Coerção e ruptura estilísticas na poesia potiguar: a construção do ethos inventivo do poeta Jorge Fernandes

Within the poetic scenario of Rio Grande do Norte the publication of Livro de Poemas de Jorge Fernandes, in 2007, marks, in the imagery of the Potiguar community of poetry readers, producers and critics, the beginning of the social circulation of an inventive ethos associated with the poet Jorge Fernandes de Oliveira (1887-1953). Regarding the event mentioned earlier as a point of reference, this research investigates the construction of such ethos based on the counterpoint between the poet s individual stylistic choices and the stylistic options that prevailed in the lyric production of the Twenties in the 20th Century. The corpus comprises poetic texts (by the poet under discussion and by other poets who were, then, regarded as icons of the poetry of Rio Grande do Norte) and texts representative of local literary criticism (produced both during the Twenties and in other decades of the last century). Support to this analysis is grounded in Mikhail Bakhtin s theory of the utterance (mainly regarding style) and in Dominique Maingueneau s theory of the utterance (mainly regarding ethos). During the course of this investigation, the research has outlined an inventory of the prevailing individual stylistic choices of Jorge Fernandes de Oliveira and the reasons why such choices point out towards the inventive ethos associated with the poet.

Uso da palha de carnaúba em revestimento de dutos

In this work, the plant species Copernicia prunifera (Miller) H. E. Moore (carnauba), naturally occurring which prevails in the northeast region of Brazil was the subject of studies aiming its use as external coating of pipelines used in petroleum industry. The part of the plant worked were the leaves, also called straw, which were coated with resinous material. For this purpose, it was necessary to evaluate the effectiveness of the use of acrylic resins in the straw carnauba coating. The properties of the untreated carnauba straw and chemically treated with sodium hydroxide, hexane and carbon tetrachloride were investigated by ATRFTIR, SEM and thermal analysis. The first two techniques showed that treatment with solvents has caused major changes in the straw surface, while the thermal analysis indicated that the sodium hydroxide caused variations in thermal stability of straw constituents. Water absorption measurements showed that treatments have accelerated the absorption process and the reduction of contact angle values for treated samples with solvents indicated higher hidrophilicity of straw. The tensile tests showed lower values of elastic modulus and tensile strength for treated samples. Furthermore, coatings using pure commercial resins A and B as well as the formulations with clay were applied in straw and they were examined once again through thermal analysis, water absorption measurements, contact angle and mechanical tests. To analyze the effect of heat ageing, samples were subjected to tensile tests again in order to assess its resistance. The results showed that the resins/clay formulations increased thermal stability of straw, they promoted a good impermeabilization and caused significant decrease in the values of elastic modulus and tensile strength. Evaluating the ageing effect on the mechanical properties, it has been showed good recovery to the coated straw with the formulations A 60 and A 80% in modulus and tensile strength values and elongation at break values have remained very close. It is thus concluded that the carnauba straw can be used as a coating of pipelines with significant cost savings, since there is no need for pretreatment for its use and shows itself as a viable biotechnology alternative, contributing to the quality of coatings material and environment preservation.

Prova automática de satisfatibilidade módulo teoria aplicada ao método B

Este trabalho apresenta uma extensão do provador haRVey destinada à verificação de obrigações de prova originadas de acordo com o método B. O método B de desenvolvimento de software abrange as fases de especificação, projeto e implementação do ciclo de vida do software. No contexto da verificação, destacam-se as ferramentas de prova Prioni, Z/EVES e Atelier-B/Click n Prove. Elas descrevem formalismos com suporte à checagem satisfatibilidade de fórmulas da teoria axiomática dos conjuntos, ou seja, podem ser aplicadas ao método B. A checagem de SMT consiste na checagem de satisfatibilidade de fórmulas da lógica de primeira-ordem livre de quantificadores dada uma teoria decidível. A abordagem de checagem de SMT implementada pelo provador automático de teoremas haRVey é apresentada, adotando-se a teoria dos vetores que não permite expressar todas as construções necessárias às especificações baseadas em conjuntos. Assim, para estender a checagem de SMT para teorias dos conjuntos destacam-se as teorias dos conjuntos de Zermelo-Frankel (ZFC) e de von Neumann-Bernays-Gödel (NBG). Tendo em vista que a abordagem de checagem de SMT implementada no haRVey requer uma teoria finita e pode ser estendida para as teorias nãodecidíveis, a teoria NBG apresenta-se como uma opção adequada para a expansão da capacidade dedutiva do haRVey à teoria dos conjuntos. Assim, através do mapeamento dos operadores de conjunto fornecidos pela linguagem B a classes da teoria NBG, obtem-se uma abordagem alternativa para a checagem de SMT aplicada ao método B

MoSAC: um módulo para seleção de configurações arquiteturais baseado em critérios de QoS no contexto de sistema distribuídos autoadaptativos

The process for choosing the best components to build systems has become increasingly complex. It becomes more critical if it was need to consider many combinations of components in the context of an architectural configuration. These circumstances occur, mainly, when we have to deal with systems involving critical requirements, such as the timing constraints in distributed multimedia systems, the network bandwidth in mobile applications or even the reliability in real-time systems. This work proposes a process of dynamic selection of architectural configurations based on non-functional requirements criteria of the system, which can be used during a dynamic adaptation. This proposal uses the MAUT theory (Multi-Attribute Utility Theory) for decision making from a finite set of possibilities, which involve multiple criteria to be analyzed. Additionally, it was proposed a metamodel which can be used to describe the application s requirements in terms of the non-functional requirements criteria and their expected values, to express them in order to make the selection of the desired configuration. As a proof of concept, it was implemented a module that performs the dynamic choice of configurations, the MoSAC. This module was implemented using a component-based development approach (CBD), performing a selection of architectural configurations based on the proposed selection process involving multiple criteria. This work also presents a case study where an application was developed in the context of Digital TV to evaluate the time spent on the module to return a valid configuration to be used in a middleware with autoadaptative features, the middleware AdaptTV

Java-XSC : módulo complexo e complexo intervalar

This work aims to develop modules that will increase the computational power of the Java-XSC library, and XSC an acronym for "Language Extensions for Scientific Computation . This library is actually an extension of the Java programming language that has standard functions and routines elementary mathematics useful interval. in this study two modules were added to the library, namely, the modulus of complex numbers and complex numbers of module interval which together with the modules original numerical applications that are designed to allow, for example in the engineering field, can be used in devices running Java programs

Estudo da previsão da carga de ruptura de estacas pré-moldadas de concreto

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.

Implementação em FPGA de módulo de efeito de reverberação

Reverberation is caused by the reflection of the sound in adjacent surfaces close to the sound source during its propagation to the listener. The impulsive response of an environment represents its reverberation characteristics. Being dependent on the environment, reverberation takes to the listener characteristics of the space where the sound is originated and its absence does not commonly sounds like “natural”. When recording sounds, it is not always possible to have the desirable characteristics of reverberation of an environment, therefore methods for artificial reverberation have been developed, always seeking a more efficient implementations and more faithful to the real environments. This work presents an implementation in FPGAs (Field Programmable Gate Arrays ) of a classic digital reverberation audio structure, based on a proposal of Manfred Schroeder, using sets of all-pass and comb filters. The developed system exploits the use of reconfigurable hardware as a platform development and implementation of digital audio effects, focusing on the modularity and reuse characteristics

Contribuições para o processo de verificação de satisfatibilidade módulo teoria em Event-B

Event-B is a formal method for modeling and verification of discrete transition systems. Event-B development yields proof obligations that must be verified (i.e. proved valid) in order to keep the produced models consistent. Satisfiability Modulo Theory solvers are automated theorem provers used to verify the satisfiability of logic formulas considering a background theory (or combination of theories). SMT solvers not only handle large firstorder formulas, but can also generate models and proofs, as well as identify unsatisfiable subsets of hypotheses (unsat-cores). Tool support for Event-B is provided by the Rodin platform: an extensible Eclipse based IDE that combines modeling and proving features. A SMT plug-in for Rodin has been developed intending to integrate alternative, efficient verification techniques to the platform. We implemented a series of complements to the SMT solver plug-in for Rodin, namely improvements to the user interface for when proof obligations are reported as invalid by the plug-in. Additionally, we modified some of the plug-in features, such as support for proof generation and unsat-core extraction, to comply with the SMT-LIB standard for SMT solvers. We undertook tests using applicable proof obligations to demonstrate the new features. The contributions described can potentially affect productivity in a positive manner.

Estudo morfológico da blenda polimérica poli(metacrilato de metila)/poli(tereftalato de etileno) reciclado (PMMA/PET)

Among the options for plastics modification more convenient, both from a technical-scientific and economic, is the development of polymer blends by processing in the molten state. This work was divide into two stages, with the aim to study the phase morphology of binary blend PMMA / PET blend and this compatibilized by the addition of the poly(methyl methacrylate-co-glycidyl methacrylate-co-ethyl acrylate) copolymer (MMA-GMA-EA). In the first stage is analyzed the morphology of the blend at a preliminary stage where we used the bottle-grade PET in a Haake torque rheometer and the effect of compatibilizer in this blend was evaluated. In the second stage the blend was processed using the recycled PET in a single screw extruder and subsequently injection molding in the shape of specimens for mechanical tests. In both stages we used a transmission electron microscopy (TEM) to observe the morphologies of the samples and an image analyzer to characterize them. In the second stage, as well as analysis by TEM, tensile test, scanning electron microscopy (SEM) and atomic force microscopy (AFM) was performed to correlate the morphology with the mechanical properties. The samples used in morphological analyzes were sliced by cryo-ultramicrotomy technique for the analysis by TEM and the analysis by SEM and AFM, we used the flat face of the block after cut cryogenic. It was found that the size of the dispersed phase decreased with the addition of MMA-GMA-EA in blends prepared in a Haake. In the tensile test, the values of maximum tensile strength and modulus of elasticity is maintained in a range between the value of pure PMMA the pure PET, while the elongation at break was influenced by the composition by weight of the PMMA mixture. The coupling agent corroborated the results presented in the blend PMMA / PETrec / MMA-GMA-EA (80/15/5 %w/w), obtained by TEM, AFM and SEM. It was concluded that the techniques used had a good morphologic correlation, and can be confirmed for final analysis of the morphological characteristics of the blends PMMA / PET

O efeito do tratamento da atapulgita no desenvolvimento de compósito com o polietileno reciclado

The study aimed at the treatment of attapulgite for the development and characterization of composite recycled low density polyethylene - PEBD_rec embedded with natural attapulgite - ATP_NAT, sifted - ATP_PN and attapulgite treated with sulfuric acid - ATP_TR in different compositions (1, 3 and 5%) and compared with the PEBD_rec. The atapulgitas, natural, screened and treated, were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), particle size analysis, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and determining the area specific surface (BET). The composites were characterized by thermogravimetry (TG), differential scanning calorimetry (DSC), Xray diffraction (XRD), torque rheometry, scanning electron microscopy (SEM) and traction. The composite PEBD_rec / ATP (natural, sieved and treated) were produced by mixing in the molten state in a single screw extruder matrix wire with subsequent reprocessing matrix tape. It was found that the screening of attapulgite not reduce the quantity of quartz and the acid treatment completely extracted dolomite aggregate impurities of the channels attapulgite, and increase their surface area. The addition of attapulgite in PEBD_rec acts as a catalyst, reducing the thermal stability of the polymer. The increased concentration of attapulgite, increases resistance and reduces the elongation at break and modulus of elasticity of the composite PEBD_rec / attapulgite