Análise das propriedades físico-mecânicas de painel particulado de eucalipto composto por três camadas com duas variações de pressão

The research aimed to produce sheets of particles with waste processing of Eucalyptus sp bonded with urea-formaldehyde and evaluate the effect of pressure variation in the quality of the boards produced. To do so, the Boards made were divided into two treatments depending on the pressing pressure of 30 to 40 kgf / cm². Once pressings, climatized, the particleboards have been sectioned in test samples, and underwent physical-mechanical tests for determining density, swelling and water absorption, modulus of rupture and elasticity in static bending and internal linking. The particleboards pressed at 40 kgf / cm ² showed the best results

Produção e caracterização físico-mecânica do compósito cimento-madeira com variação granulométrica dos resíduos lignocelulósicos

The need to reduce environmental damage and add value to waste causes more and more new alternatives appear to unite these two points. One of the main ways to achieve this in timber industries and the use of waste for making panels. This work was aimed at studying the influence of particle size and density in Eucalyptus mechanical compressive strength of cement composite wood. For this study was performed production and physico-mechanical characterization of specimens, using portland cement, water and waste eucalyptus. The methodology consists of a statistical study of the results obtained by calculating the density and axial compression tests and a subsequent comparison of these results with other studies. The results showed that there are significant differences in density and compressive strength when using different particle sizes the particles of eucalyptus. In general, the smaller the particle size, the lower the compression strength and the greater the density when the samples are produced with the same trait

Reciclagem de poliestireno expandido: compósito com fibras de algodão para a confecção de placas de circuito impresso

In this work polymeric composites reinforced with cotton fibers, from the textile industry, were developed in order to manufacture printed circuit boards. It was used expanded polystyrene (EPS) as a thermoplastic matrix by melting it. For the obtention of 10% and 15% of fiber volume fraction in cotton fibers composites, it was used wasted cotton fibers as an incentive of recycling and reusing of the domestic and industrial wastes as well as for Expanded Polystyrene(EPS). The mechanical properties of the composites were evaluated by tensile and flexural strength from standardized test methods. Composites were characterized by a Scanning Electron Microscopy (SEM), Thermogravimetry (TG/DTG), Differential Scanning Calorimetry (DSC) and dielectric analysis. The analysis of the results showed that fiber in the composite directly influenced in the thermal and mechanical properties

Avaliação do efeito ambiental nas propriedades mecânicas e viscoelásticas de compósitos híbridos de titânio/fibra de carbono/resina epóxi

Hybrid composites combining metal plates and laminates with continuous fiber reinforced polymer, called fiber-metal (CHMF), have been particularly attractive for aerospace applications, due mainly to their high mechanical strength and stiffness associated with low density. These laminates (CHMF) consist of a sandwich structure consisting of layers of polymer composites and metal plates, stacked alternately. This setting allows you to combine the best mechanical performance of polymer composites reinforced with long fibers, to the high toughness of metals. Environmental effects should always be considered in the design of structural components, because these materials in applications are submitted to the effects of moisture in the atmosphere, the large cyclical variations of temperature around 82 ° C to -56 ° C, and high effort mechanical. The specimens of fibermetal composite were prepared at EMBRAER with titanium plates and laminates of carbon fiber/epoxy resin. This study aims to evaluate the effect of different environmental conditions (water immersion, hygrothermal chamber and thermal shock) of laminate hybrid titanium/carbon fiber/epoxy resin. The effects of conditioning were evaluated by interlaminar shear tests - ILSS, tensile, and vibration free

Reciclagem de poliestireno expandido: compósito com fibras de sisal para confecção de placas de circuito impresso

In this work polystyrene composites reinforced with recycled sisal fibers were processed, in order to apply in the manufacture of printed circuit boards. A thermoplastic matrix of recycled polystyrene was used, this material came from waste expanded polystyrene (EPS) used in appliance's packages. Composites were prepared with 15% and 25% of sisal fibers. To obtain the composites, wasted EPS and natural sisal fibers were chosen, to encourage recycling and reuse of household waste and also the use of renewable resources. The composites were analyzed by standard tensile and flexural test, in order to verify the mechanical properties of the material. The characterization of the composite was done by scanning electron microscopy (SEM) , thermogravimetry (TGA / DTG) , differential scanning calorimetry (DSC) and dielectric analysis . The analysis of the results showed that the percentage of fibers in the composite influences directly the thermal and mechanical properties. Plates with a lower percentage of fibers showed superior properties at a higher percentage. The composite material obtained is easy to process and it's use is feasible for the confection of printed circuit boards, considering it's mechanical, thermal and insulative properties

Análise comparativa entre Brasil e Alemanha sobre autoprodução de energia elétrica residencial

The energy crisis has affected many countries. With the growing warning with the emission in the atmosphere and the lack of resources, the seek for sustainable sources for energy genaration have become even bigger. Some Countries, as Germany, started first in this journey, creating an incentive program to self-generation with renewable sources (wind, photovoltaics, biomass, etc.), giving priority for smaller plants. In Germany the program called EEG started in 2004. In Brazil, since the beggining of 2012, the self-generators did not know how they could be beneficted for self-generation, and self-generation didn't become commun in the country. However, with NR 482, of April 17th, 2012, the parameters were defined, and the self-generator could have a guideline. Therewith, studyies can be redirected for a better knowlegde of the conditions the self-generator will be sujected, in addition to Germany's case as reference to compare with Brazil's case. In this paper these studies are made, focused in wind power (wind turbines) and photovoltaic panels

Efeito protetor da proteína anti-inflamatória Galectina-1 sobre o processo de uveíte induzida pelo inflamógeno lipopolissacarídeo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

O ensino da compostagem e produção de sabão como forma de gerenciamento dos resíduos sólidos domiciliares

Introdução: O adequado gerenciamento dos resíduos sólidos domiciliares (RSD) tem se estabelecido nas últimas décadas como um importante instrumento na diminuição do lixo doméstico destinados aos aterros. A compostagem doméstica e a produção de sabão a partir de óleo usado são alternativas para a reciclagem dos RSD que, ao contrário dos lixos recicláveis, não são explorados comercialmente. Assim, o ensino dessas técnicas para a comunidade pode ser uma ferramenta útil na educação ambiental, disseminando práticas que evitam a destinação final de resíduos sólidos em aterros e desenvolvendo valores para a sustentabilidade. Objetivos: Ensinar formas de reciclagem dos RSD através de técnicas de compostagem e produção de sabão a partir de óleo usado, servindo também como instrumento para promover a educação ambiental, e conscientizar a comunidade sobre a importância de um adequado gerenciamento de resíduos. Métodos: As atividades de ensino consistiram em duas partes, unindo teoria e prática, por meio da apresentação de painéis explicativos sobre compostagem, produção de sabão, e sobre as vantagens decorrentes desses processos seguida da realização das técnicas apresentadas, com a produção de sabão em barra e líquido com óleo usado, e pela montagem de pequenas composteiras em garrafões PET de 5 litros de água mineral reaproveitados. Resultados: As atividades foram realizadas em eventos abertos a sociedade de São José do Rio Preto, tais como a Semana da Tecnologia, em outubro de 2010 e a Semana do Meio Ambiente, em junho de 2011, ambas desenvolvidas no SESC (Serviço Social do Comércio) da cidade. O público foi variado, incluindo desde aposentados e donas de casa até estudantes e profissionais de diversos setores. O interesse em anotar as metodologias explicadas culminou na idéia de produzir um material impresso que contivesse as receitas de sabão (líquido e em barra), os procedimentos e dicas de como realizar a compostagem. A convite de uma escola pública, houve também a apresentação das atividades para pais de alunos e funcionários interessados em aprender as práticas para o adequado gerenciamento dos RSD, levando à discussão das possibilidades de implantação de um projeto de compostagem na própria escola.

Aplicação do conceito de geração distribuída a um sistema fotovoltaico residencial

This work presents a study about distributed generation using photovoltaic systems in the context of smart grids. The characteristics of a Smart Grid and the several aspects this concept involves - distributed generation among them - are discussed. There are also examples of equipment, like smart meters, and of national and international projects. The specificities of distributed generation and the rules and standards necessary in this sort of installation are talked through with focus in the solar energy generation method. Regarding photovoltaic systems, the working principles of the panels are presented, along with its main electrical characteristics and the technologies available. Finally there is a study concerning the sizing of a distributed generation system that involves photovoltaic panels in a residential plant. An analysis of the costs and return of investment period is made about the specific case in consideration.

Efeito do tratamento alcalino da fibra na resistência mecânica do compósito epóxi/capim-sapê

Due to growing concerns for reducing environmental damage caused by the use of non-renewable raw materials, there is a growing demand for research related to aggregate technology with environmental preservation. Thus, the use of non-renewable materials and less aggressive materials has been gaining attention. About composite materials, the exchange of synthetic fibers by natural fibers, especially vegetable fiber as reinforcement, has been increasing, due to its physical-chemical properties such as mechanical strength, nontoxic, low cost, low density, processing flexibility, non-abrasive to the process equipment, requiring simple surface treatments, etc. This objective was to process composites reinforced with long fibers of sapegrass in epoxy matrix and characterize the composites through mechanical tests. Three groups of composites were prepared according to the treatment received by the reinforcement: without treatment, alkali treatment at concentration of 5% w/v and alkali treatment at 10% w/v concentration. The materials were analyzed by tensile and flexural, and tests also optical microscopy and scanning electron microscopy (SEM). The results were statistically analyzed. As the main result, the alkali treatment of 5% in the sapegrass fibers increases the tensile and flexural strength, as a consequence of the improve adhesion between matrix and reinforcement

Chaveamento de cargas intermitentes usando sensor de corrente

Due to concerns about rational use of energy, several alternative technologies of power generation appeared, including the conversion of solar energy into electrical energy by photovoltaic panels. In low-income households, the refrigerator represents considerable impact on the electric bill, since it requires constant power given its use in food preservation. It is possible to reduce this share, with the use of an alternative energy source. This work presents a timed switching electronic system, which allows commercial equipment that is not affected by short interruptions in the power supply to use a photovoltaic panel as a source of alternative energy, which usually do not provide energy continuously. Switching is made automatically in case of low incidence of sunlight, and without any form of energy storage. Between each switching, there is a dead time without power supply, therefore preventing the use of synchronizers circuits between the photovoltaic panel and the public power grid. A circuit containing a 80C31 microcontroller is used to control the system’s switching. The photovoltaic panel’s voltage inverter is in H bridge configuration, and is also controlled by the microcontroller through Pulse Width Modulation, which makes use of preprogrammed tables to generate the control signals of the power transistors. Through the use of software simulations, the proposed system was tested, which is capable of supplying intermittent single-phase loads. The simulations indicates that the project developed in this paper can be assembled into a prototype and be tested under real operating conditions, as long as the scaling of components, the characteristics of the photovoltaic panel to be used, and the project involved load are taken into account

Comportamentos, térmico e mecânico, de compósitos de polipropileno e resíduo da hidrólise enzimática do bagaço de cana de açúcar

Pós-graduação em Engenharia Mecânica - FEG

Análise do processo de fresamento de MDF em centro de usinagem CNC

Pós-graduação em Engenharia Mecânica - FEG

Correlação das características ultrassonográficas com perfil imunoistoquímico dos tumores mamários malignos

Pós-graduação em Ginecologia, Obstetrícia e Mastologia - FMB

Considerações e avaliações das solicitações em estruturas de edificações de paredes de concreto pré-moldado utilizando o modelo de pórtico tridimensional: estudo de caso

The present study is in reference to precast concrete (panels) walls as the main structural system. The diversification of the structural systems is a reality due to specific characteristics', as a result there is a lack of study and analysis. Some systems are already established in their applications, for instance: conventional reinforced concrete, structural masonry, metal structures, and wood structure. Apart from this precast concrete elements has had a growth in building sites in Brazil, therefore professionals should be more aware. Affordable house funding initiatives to address the housing shortage has been recurrent throughout the country, additionally precast concrete walls has been an alternative that meets the three basic concepts of engineering, which are: the technique, economy, and security. The objective of this study is to gather concepts from the literature and TOMO (2012) about precast concrete walls and make a didactic synthesis of how they are viewed. The modeling structure method of the system was performed following the concept of assigning bars, using the computer program of calculations SAP2000. Initially will be presented a theoretical part, furthermore a case study to illustrate the sizing of the walls using EXCEL tables programmed with calculation routine. The results will be presented in calculated efforts by the program for further analysis. Finally, will be highlighted important items of modeling and interpretation of the results