Utilização de resíduo lignocelulósico na obtenção de chapa de madeira aglomerada homogênea e compósito reforçado com fibra de vidro-E

This research is about the use of the coconut´s endocarp (nucifera linn) and the waste of derivatives of wood and furniture as raw material to technological use. In that sense, the lignocellulosic waste is used for manufacture of homogeneous wood sheet agglomerate (LHWS) and lignocellulosic load which take part of a polymeric composite with fiber glass E (GFRP-WC). In the manufacturing of the homogeneous wood sheet agglomerate (LHWS), it was used mamona´s resin as waste s agglutinating element. The plates were taken up in a hydraulic press engine, heated, with temperature control, where they were manufactured for different percentage of waste wood and coconuts nucífera linn. Physical tests were conducted to determine the absorption of water, density, damp grade (in two hours and twenty-four hours), swelling thickness (in two hours and twenty-four hours), and mechanical tests to evaluate the parallel tensile strength (internal stick) and bending and the static (steady) flexural. The physical test´s results indicate that the LHWS can be classified as bonded wood plate of high-density and with highly water resistant. In the mechanical tests it was possible to establish that LHWS presents different characteristics when submitted to uniaxial tensile and to the static (steady) flexural, since brittle and elasticity module had a variation according to the amount of dry endocarp used to manufacture each trace of LHWS. The GFRP-WC was industrially manufactured by a hand-lay-up process where the fiber glass E was used as reinforcement the lignocellulósic´s waste as load. The matrix was made with ortofitalic unsaturated polyester resin. Physical and mechanical tests were performed in presence of saturated humidity and dry. The results indicated good performance of the GFRP-WC, as traction as in flexion in three points. The presence of water influenced the modules obtained in the flexural and tensile but there were no significant alteration in the properties analyzed. As for the fracture, the analysis showed that the effects are more harmful in the presence of damp, under the action of loading tested, but despite this, the fracture was well defined starting in the external parts and spreading to the internal regions when one when it reaches the hybrid load

Otimização e análise mecânica de pastas geopoliméricas para uso em poços sujeitos à injeção cíclica de vapor

Oil wells subjected to cyclic steam injection present important challenges for the development of well cementing systems, mainly due to tensile stresses caused by thermal gradients during its useful life. Cement sheath failures in wells using conventional high compressive strength systems lead to the use of cement systems that are more flexible and/or ductile, with emphasis on Portland cement systems with latex addition. Recent research efforts have presented geopolymeric systems as alternatives. These cementing systems are based on alkaline activation of amorphous aluminosilicates such as metakaolin or fly ash and display advantageous properties such as high compressive strength, fast setting and thermal stability. Basic geopolymeric formulations can be found in the literature, which meet basic oil industry specifications such as rheology, compressive strength and thickening time. In this work, new geopolymeric formulations were developed, based on metakaolin, potassium silicate, potassium hydroxide, silica fume and mineral fiber, using the state of the art in chemical composition, mixture modeling and additivation to optimize the most relevant properties for oil well cementing. Starting from molar ratios considered ideal in the literature (SiO2/Al2O3 = 3.8 e K2O/Al2O3 = 1.0), a study of dry mixtures was performed,based on the compressive packing model, resulting in an optimal volume of 6% for the added solid material. This material (silica fume and mineral fiber) works both as an additional silica source (in the case of silica fume) and as mechanical reinforcement, especially in the case of mineral fiber, which incremented the tensile strength. The first triaxial mechanical study of this class of materials was performed. For comparison, a mechanical study of conventional latex-based cementing systems was also carried out. Regardless of differences in the failure mode (brittle for geopolymers, ductile for latex-based systems), the superior uniaxial compressive strength (37 MPa for the geopolymeric slurry P5 versus 18 MPa for the conventional slurry P2), similar triaxial behavior (friction angle 21° for P5 and P2) and lower stifness (in the elastic region 5.1 GPa for P5 versus 6.8 GPa for P2) of the geopolymeric systems allowed them to withstand a similar amount of mechanical energy (155 kJ/m3 for P5 versus 208 kJ/m3 for P2), noting that geopolymers work in the elastic regime, without the microcracking present in the case of latex-based systems. Therefore, the geopolymers studied on this work must be designed for application in the elastic region to avoid brittle failure. Finally, the tensile strength of geopolymers is originally poor (1.3 MPa for the geopolymeric slurry P3) due to its brittle structure. However, after additivation with mineral fiber, the tensile strength became equivalent to that of latex-based systems (2.3 MPa for P5 and 2.1 MPa for P2). The technical viability of conventional and proposed formulations was evaluated for the whole well life, including stresses due to cyclic steam injection. This analysis was performed using finite element-based simulation software. It was verified that conventional slurries are viable up to 204ºF (400ºC) and geopolymeric slurries are viable above 500ºF (260ºC)

Avaliação de concretos reforçados por confinamento com manta de fibra de vidro estrutural e pré-impreganada

Due to the occurrence of diseases in the use of structural reinforcements in composites, with presentation of concrete blanket detachment, has been identified the need to evaluate the performance of concrete reinforced with glass fiber. This study aims to evaluate these concretes by means of testing methodologies, using concrete with low resistance with structural reinforcement for confinement by preimpregnated glass fiber and traditional fiberglass blanket. The first stage of work was the development of methodologies for analysis, opting for four types, such as the acoustic survey, strength to compressive, the pull-off and ultrasound. Next, tests were carried out using the four selected methodologies in 30 of proof-of-specimens by 5x10 cm, 15 were reinforced with the traditional fiberglass blanket with 5specimens exposed to test a marine environment of marine coastline of Natal-RN and 15 were reinforced with a pre-impregnated glass fiber blanket, as well as 5specimens exposed to a test environment of the marine coastline of Natal-RN. After conducting the acoustic survey, it has been verified a lack of delaminating and air bubbles in the samples, confirming the absence of gross shortcomings in the implementation of the ribs both the traditional fiberglass blanket and in the preimpregnated fiber glass blanket. After carrying out methods of pull-off and compressive strengthening test it was observed that the reinforced proof-bodies with pre-impregnated glass blanket showed maximum stresses higher than the traditional fiberglass blanket; consequently a greater grip with the formation of a smaller area of . fracture, unlike traditional glass mat, which showed lower maximum stresses, with a greater area of fracture. It was also found that the traditional fiberglass blanket presented detachment of blanket-concrete interface, unlike the pre-impregnated fiberglass blanket, which showed a better grip on the blanket-concrete interface. In the trial of ultrasound there was no presence of cracks in the blanket-concrete interface, yielding to both blankets good compactness of the concrete. At the end of this work, they were developed and proposed two methods of testing for evaluation of reinforced concrete structures with composites, for standardization, the acoustic survey and pull-off

Estudo comparativo de pás para aerogeradores de grande porte fabricadas em materiais compósitos reforçadas com fibra de carbono ou fibra de vidro

The research and development of wind turbine blades are essential to keep pace with worldwide growth in the renewable energy sector. Although currently blades are typically produced using glass fiber reinforced composite materials, the tendency for larger size blades, particularly for offshore applications, has increased the interest on carbon fiber reinforced composites because of the potential for increased stiffness and weight reduction. In this study a model of blade designed for large generators (5 MW) was studied on a small scale. A numerical simulation was performed to determine the aerodynamic loading using a Computational Fluid Dynamics (CFD) software. Two blades were then designed and manufactured using epoxy matrix composites: one reinforced with glass fibers and the other with carbon fibers. For the structural calculations, maximum stress failure criterion was adopted. The blades were manufactured by Vacuum Assisted Resin Transfer Molding (VARTM), typical for this type of component. A weight comparison of the two blades was performed and the weight of the carbon fiber blade was approximately 45% of the weight of the fiberglass reinforced blade. Static bending tests were carried out on the blades for various percentages of the design load and deflections measurements were compared with the values obtained from finite element simulations. A good agreement was observed between the measured and calculated deflections. In summary, the results of this study confirm that the low density combined with high mechanical properties of carbon fibers are particularly attractive for the production of large size wind turbine blades

Compósitos poliméricos a base de fibras de licuri: efeitos da hibridização e do envelhecimento ambiental acelerado

The gradual replacement of conventional materials by the ones called composite materials is becoming a concern about the response of these composites against adverse environmental conditions, such as ultraviolet radiation, high temperature and moist. Also the search for new composite using natural fibers or a blend of it with synthetic fibers as reinforcement has been studied. In this sense, this research begins with a thorough study of microstructural characterization of licuri fiber, as a proposal of alternative reinforcement to polymeric composites. Thus, a study about the development of two composite laminates was done. The first one, involving only the fiber of licuri and the second comprising a hybrid composite based of fiber glass E and the fiber of licuri, in order to know the performance of the fiber when of fiber across the hybridization process. The laminates were made in the form of plates using the tereftálica ortho-polyester resin as matrix. The composite laminate made only by licuri fiber had two reinforcing fabric layers of unidirectional licuri and the hybrid composite had two reinforcing layers of unidirectional licuri fabric and three layers of fiber short glass-E mat. Finally, both laminates was exposed to aging acceleration in order to study the influence of environmental degradation involving the mechanical properties and fracture characteristics thereof. Regarding the mechanical properties of composites, these were determined through uniaxial tensile tests, uniaxial compression and three bending points for both laminates in original state, and uniaxial tensile tests and three bending points after accelerated aging. As regards the study of structural degradation due to aging of the laminates, it was carried out based on microscopic analysis and microstructure, as well as measuring weight loss. The characteristics of the fracture was performed by macroscopic and microscopic (optical and SEM) analysis. In general, the laminated composites based on fiber licuri showed some advantages in their responses to environmental aging. These advantages are observed in the behavior related to stiffness as well as the microstructural degradation and photo-oxidation processes. However, the structural integrity of this laminate was more affected in case the action of uniaxial tensile loads, where it was noted a lower rate of withholding his last resistance property

Efeito da adição de grafite expandido por microondas nas propriedades térmicas, elétricas e mecânicas de nanocompósitos de matriz epóxi

Epoxy based nanocomposites with 1 wt % and 3 wt % of nanographite were processed by high shear mixing. The nanographite was obtained by chemical (acid intercalation), thermal (microwave expansion) and mechanical (ultrasonic exfoliation) treatments. The mechanical, electrical and thermal behavior of the nanocomposites was determined and evaluated as a function of the percentage of reinforcement. According to the experimental results, the electrical conductivity of epoxy was not altered by the addition of nanographite in the contents evaluated. However, based on the mechanical tests, nanocomposites with addition of 1 wt.% and 3 wt.% of nanographite showed increase in tensile strength of 16,62 % and 3,20 %, respectively, compared to the neat polymer. The smaller increase in mechanical strength of the nanocomposite with 3 wt.% of nanographite was related to the formation of agglomerates. The addition of 1 wt.% and 3 wt.% of nanographite also resulted in a decrease of 6,25 % and 17,60 %, respectively, in the relative density of the material. Thus, the specific strength of the nanocomposites was approximately 33,33 % greater when compared to the neat polymer. The addition of 1 wt.% and 3 wt.% of nanographite in the material increased the mean values of thermal conductivity in 28,33 % and 132,62 %, respectively, combined with a reduction of 26,11 % and 49,80 % in volumetric thermal capacity, respectively. In summary, it has been determined that an addition of nanographite of the order of 1 wt.% and 3 wt.% produced notable elevations in specific strength and thermal conductivity of epoxy

Estudo sobre as potencialidades de compósitos à base de gesso e fibras de coco seco para aplicação na construção civil

The use of gypsum, one of the oldest building materials for the construction industry in the country has been experiencing a significant and steady growth, due to its low cost and some of its properties that confer comparative advantage over other binder materials. Its use comprises various applications including the coating of walls and the production of internal seals and linings. Moreover, the fibers are being increasingly incorporated into arrays fragile in an attempt to improve the properties of the composite by reducing the number of cracks, the opening of the same and its propagation velocity. Other properties, depending on the function of the component material or construction, among these thermal and acoustic performances, are of great importance in the context of buildings and could be improved, that is, having better performance with this embodiment. Conduct a comparative study of physico-mechanical, thermal and acoustic composite gypsum incorporating dry coconut fiber, in the form of blanket, constituted the main objective of this work. Improving the thermal and acoustic performances of precast gypsum, used for lining and internal vertical fences of buildings, was the purpose of development of these composites. To evaluate the effect of fiber content on the properties of the composites were used to manufacture the composite layer with different thicknesses. The composites were fabricated in the form of plates with dimensions of 500x500x24mm. To facilitate the comparative study of the properties were also made with material gypsum boards only. We then determined the physico-mechanical, thermal and acoustical plaster and composites. The results indicated that the composites were significant gains in relation to thermal performance and also acoustic, in certain frequency range, increasing the thickness of the blanket. Concerning other physical-mechanical properties, the results showed that although the compressive strength was lower than for the composite did not occur after a fracture catastrophic failure. The same trend was observed with regard to resistance to bending, since the composites have not suffered sudden rupture and still continued after the load supporting point of maximum load

Desenvolvimento e caracterização de compósito a partir da borra da piaçava para construção da parábola de um fogão solar a concentração

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Efeito da adição de microfibras de lã de vidro na tenacidade à ruptura de pastas de cimento para poços de petróleo

Although there are a wide variety of additives that act in fresh state, to adjust the properties of cement, there is also a search by additions that improve the tenacity of the cement in the hardened state. This, in turn, can often be increased by inserting fibers, which act on the deflection of microcracks. This study aimed to use a microfiber glass wool (silica-based) as an additive reinforcing the cement matrix, improving the rupture tenacity, in order to prevent the propagation of microcracks in the cement sheath commonly found in oil wells submitted to high temperatures. The fibers were added at different concentrations, 2 to 5% (BWOC) and varied average sizes, grinding for 90 s, 180 s, 300 s, 600 s. The cement slurries were made with a density of 1,90 g/ cm3 (15,6 lb/gal), using Portland cement CPP- Special Class as the hydraulic binder and 40% silica flour. The characterization of the fiber was made by scanning electron microscopy (SEM), particle size by sieving, X-ray fluorescence (XRF), X-ray diffraction (XRD) and thermogravimetry (TG / DTG). Were performed technological tests set by the API (American Petroleum Institute) by rheology, stability, free water, compressive strength, as well as testing rupture energy, elastic modulus and permeability. The characterization results showed good thermal stability of the microfiber glass wool for application in oil wells submitted to steam injection and, also, that from the particle size data, it was possible to suggest that microfibers milled up to 300 s, are ideal to act as reinforcement to the cement slurries. The rheological parameters, there was committal of plastic viscosity when larger lengths were inserted of microfiber (F90). The values obtained by free water and stability were presented according to API. The mechanical properties, the incorporation of microfiber to the cement slurries gave better rupture tenacity, as compared to reference cement slurries. The values of compressive strength, elastic modulus and permeability have been maintained with respect to the reference cement slurries. Thus, cement slurries reinforced with microfiber glass wool can ensure good application for cementing oil wells submitted to steam injection, which requires control of microcracks, due to the thermal gradients

Postura sentada: a eficácia de um programa de educação para escolares

Avaliação da eficácia de um programa de educação sobre o conhecimento relacionado à postura sentada de estudantes da 1ª série do ensino fundamental, na esfera estadual, particular e municipal, em Bauru. Foram avaliados (pré-teste) 71 alunos e depois aplicado um programa de educação sobre o tema, composto de aulas expositivas, técnicas de demonstração e feedback, associado a um programa de reforço ministrado por professoras treinadas e, finalmente, a reavaliação (pós-teste) dos conhecimentos dos participantes. Foi observado que: 1) no pré-teste ocorreu diferença significativa entre as escolas, sendo que a municipal apresentou menor número de erros do que a particular e a estadual; 2) o pós-teste mostrou que houve diferença significativa sendo que as escolas municipal e particular tiveram um menor número de erros em relação a estadual; 3) em todas as escolas houve predominância da situação de erro pré-teste maior que pós-teste. A escola estadual tem resposta mais freqüente que a particular quando há aumento de erro. Conclui-se que o programa se mostrou eficaz para aumentar os conhecimentos dos escolares a respeito da postura sentada.

Escola e gênero : representações de gênero na escola

The study Escola e Gênero: representações de gênero na escola show us the social man made, starting of an analysis in the having fun time in the children´s life and how it´s an important aspect of the building childish universe simbolic. My analysis started in a children´s daily at school and how they noticed the play value od dominant society. Our propouse is think about the linking between ideology, representations and gender like the children´s knowledge in the school activities. The toy, an instrument which is noticed and exist in the funny activities, is full of cultural concepts of male and female parts. Your color, lines, functions and the way you manipulate is driven of gender cathegories. In the scool, the ideological concepts have it´s important way which is to domesticate the feelings, the desires; categorize and normalize them without be known by the educational employers. In the children´s education, the funny time is noticed by others ways and turned as important as others subjects. By the way it´s not noticed by the school, like another thing which isn´t a funny moment. And it´s exactly here in the school funny time, the school did your cultural power of separete the gender and your extencions, feed by the society, generaly, in favor of the man whose woman is your subordinate. This ways of analysis help the society and the school universe about the funny time e how they are important in the Man made life. And how the toys bring the concepts and addicted thinking, ideological which put the power in the stages, without equal, addicted feelings around the gender concepts. I read and used the theories of Kishimoto, Berger & luckmann, Brougère, Sousa Filho, Bourdieu, Badinter, Geertz, Grossi, Louro, Foucault, among others

Entre o pavilhão e o inferno: trajetória dos meninos infratores no CEDUC Pitimbu

Cet étude est une recherche sur les significations imaginaires de la violence pratiquée par des jeunes délinquants ou à laquelle ils sont soumis, dans la condition de confinés chez le Centre Éducationnel CEDUC/PITIMBU, lieu où l investigation a été faite. Dans la mésure où le sujet de la violence se présente plein de manifestations, nous proposons ici une réflexion sur l imaginaire de la production théorique sur la question et en même temps nous nous proposons identifier jusqu à quel point les diverses visions scientifiques établient un savoir qui finit par limiter une conception plus complexe et profonde des réseaux de la violence. Le parcours théorique et méthodologique realisé nous a permis concluire que certaines interventions finissent par renforcer des situations limites vécues à l intèrieur du Centre par les jeunes déliquants. Parmi d autres aspects, nous traitons de l espace de l institution, leurs objectifs, routines, aussi bien que sur les principaux expressions de la violence qu apparaissent dans les récits des jeunes. Nous traitons de leurs origines socioculturelles, en signalant les milieux d oú ils viennent et leur vie quotidienne. Ainsi, nous traitons d analyser les éléments de la culture constituée, les valeurs, la « loi de plus fort », le pouvoir, le courage, la peur, l astuce, la sagesse et les rêves. Nous remarquons aussi la notion de « destin » qui renvoie à l idée que le crime et la mort sont inéluctables. Nous nous occupons de réfléchir sur le rôle de l institution dans le renforcement de la violence et dans la reproduction de valeurs sociales. Dans cet étude, nous utilisons l analyse des trajectoires de vie des jeunes délinquants pour comprendre la réalité de la violence à laquelle ils sont soumis

Anticorpos contra Leptospira spp em bovinos leiteiros vacinados com bacterina polivalente comercial: perfil sorológico frente a dois esquemas de vacinação

Mediante a utilização da prova de soroaglutinação microscópica (SAM), foi pesquisada a indução de anticorpos contra leptospira em bovinos vacinados com uma bacterina polivalente comercial. Procurou-se avaliar a resposta sorológica homóloga frente a dois esquemas de vacinação. Os animais utilizados foram fêmeas adultas em produção leiteira oriundas de seis propriedades da região noroeste do Estado de São Paulo. Vinte animais de cada propriedade foram escolhidos após três exames sorológicos com 24 sorovares de leptospiras com intervalo de 20 dias, através de triagem sorológica com 24 antígenos de leptospiras. Os grupos foram constituídos de animais não reagentes (I, II e III) e animais reagentes (IV, V e VI). Posteriormente os animais foram subdivididos em grupos controle (I e IV), os que receberam somente uma dose de vacina (II e V) e que receberam duas uma doses de vacina com e dose de reforço após 30 dias (III e VI). Os animais foram monitorados por meio da SAM nos dias 0, 15, 30, 45 e 60 após a primeira aplicação da vacina. Os resultados obtidos revelaram que não houve diferença significativa (p>0,05) entre os animais vacinados e não vacinados. Não houve diferença significativa (p>0,05) nas respostas de títulos vacinais com relação ao perfil sorológico apresentados pelos animais. A vacinação com reforço apresentou melhor desempenho e a indução produção de aglutininas somente ocorreu contra os sorovares hardjo, wolffi, icterohaemorrhagiae e pomona. Há a necessidade de maiores estudos sobre o poder imunogênico da vacina utilizada no experimento.

Immunoprophylactic strategies against enterotoxemia caused by Clostridium perfringens type D in goats

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

Literatura de monteiro lobato no ensino de ciências

Advocating education as a humanizing task, the humanizing function of literature and the importance of scientific education, this paper proposes linking Science and Literature in Science Teaching using two specific books of Monteiro Lobato in the final series of elementary school level. Adopting the action research methodology, an interdisciplinary approach, we used the books A Reforma da Natureza and Serões de Dona Benta in two classes (8th and 9th) at Escola Estadual Professor José Mamede, located in the town of Tibau do Sul, Rio Grande do Norte. The readings were performed in Portuguese Language s course and the scientific content were discussed in Science´s classrooms. The book A Reforma da Natureza permitted to approach issues related to the environment, while the use of Serões de Dona Benta showed particularly its effectiveness in questioning the concepts of matter, mass, weight and some questions about the Nature of Science (NOS). In general, the analysis of results shows that the readings of these two books permitted interaction and dialogicity in the classroom, as well as indicates the potential of these books in contextualing and questioning the scientific content contained in it. We advise, however, the need for the science teacher be aware of the conceptual mistakes present in literary works, avoiding erroneous learning and reinforcement of alternative conceptions