Analise mecânica e microestrutural em estruturas tubulares aeronáuticas soldadas de aço ABNT 4130

Airplane Motor Cradles have a complex geometry, since they require different conbinations between different tubes and TIG welded in several angles. In T-25 aircraft and Universal T-27 Tucano (EMBRAER / FAB), besides having to bear the engine balance, these components maintain fixed the nose landing gear in another extremity. They are considered critical to flight safety, and for this reason, the aviation standards are extremely rigid in their production, imposing a zero index” of defects on the final weld metal quality. These structures may be containing an historical of welding repairs, whose effects on their structural integrity are not computed. In this work we analyzed the standardised AISI 4130 steel and the raw steel of tubes to the Airplane Motor Cradles. First of all, microscopy and microanalysis of the base steel, then we analyzed the effects of the TIG weld. Tensile testing was conducted to measure the difference between the mechanical properties of standardised steel and without this treatment

Avaliação mecânica da colagem estrutural entre compósitos poliméricos e materiais metálicos utilizados em dutos petroquímicos

The development of technology for structural composites has as one of its ends form a set of materials that combine high values of mechanical strength and stiffness and low density. Today, companies like Embraer and PETROBRAS and research institutions like NASA, working with these materials with recognized advantages in terms of weight gain, increased performance and low corrosion. We have developed a systematic study to determine the bond strength between composite carbon fiber / epoxy and fiberglass / epoxy laminate both bonded to a carbon steel which are widely used in the petrochemical industry and repair. For morphological evaluation and bonding between materials of different natures, ultrasound analysis, optical microscopy and stereoscopy were performed. To simulate actual conditions, the composites were subjected to conditioning by using heat shock temperatures from -50 to 80 ° C for 1000 cycles for composite carbon fiber / epoxy composites and 2000 cycles for fiberglass / epoxy . The use of composites studied here proved to be efficient to perform repairs in metallic pipes with application petrochemical, as when exposed to sudden changes of temperature (-50 ° to 80 ° C) cycling at 1000 to 2000 times, its mechanical properties (shear and tensile) practically do not change

Estudos de foto termo e biodegradação de blendas de PEBD/PHB em colunas de solo

A grande quantidade de resíduos plásticos sintéticos descartada diariamente no meio ambiente tem preocupado governantes do mundo todo. No sentido de minimizar este problema várias soluções estão sendo propostas. Uma delas é a busca de materiais potencialmente biodegradáveis no solo. Neste trabalho desenvolveu-se blendas de poli(3-hidroxibutirato) PHB, um polímero biodegradável, com polietileno de baixa densidade PEBD, um polímero convencional e avaliou-se os efeitos do termotratamento em estufa e do fototratamento em câmara de envelhecimento acelerado sobre a biodegradação destes filmes em coluna de solo. As blendas de PEBD/PHB foram preparadas em composições de 90/10, 80/20 e 70/30, utilizando prensa sob aquecimento e os filmes foram analisados por Espectroscopia de Absorção no Infravermelho (FTIR), Microscopia de Luz Polarizada (MLP), perda de massa e ângulo de contato.

Avaliação da percepção de professores do departamento de produção e alunos do quinto ano do curso de Engenheira de Produção mecânica da Unesp de Guaratinguetá de como está o curso em relação às competências e habilidades para engenheiros

In 2002, the Ministry of Education (MEC) published the Curriculum Guidelines for Engineering courses in the country. The Guidelines contain subjects like the profile of graduates, the course structure, curriculum, internships and skills and abilities, all geared to guide the training of engineers in Brazil. The objective of this study is to evaluate together with teachers of the Production Department of this University and students of the fifth year of Production Engineering is how student learning of Production Engineering for the development and importance of skills within the course and skills for engineers who are present in the Curriculum Guidelines for engineering courses developed by MEC

Colheita de energia usando dispositivos baseados em materiais piezoelétrico

Recently, research on energy harvesting has increased substantially. Many researchers have concentrated their efforts to find the best configuration for these systems and to optimize their output power. In the process of energy harvesting, the electric energy is obtained by converting mechanics energy created by an environment vibration source by a transducer, for example, a thin piezoceramic film. That vibration source is, for example, a beam suffering some mechanic force able to generate a vibration in it, an oscillating beam is the best properly used example. Different mechanisms of electromechanical coupling have been developed to harvesting devices, and a particular interest has been given to the use of models that transform the mechanical vibration into electrical current using a piezoelectric element. In this paper we propose a model to energy harvesting from vibrations, from an oscillating beam, including non-linearities in the piezoelectric coupling and a non-ideal excitation in the material. From this model, it was developed a system to obtain some results about the harvested power by the material. It was demonstrated that the power captured was influenced by the effect of the nonlinearities of the piezoelectric coupling, modifying the system dynamic behavior

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

Caracterização físico-mecânica de elementos estruturais roliços perfilados de Amaru

The study of physical and mechanical properties of wood is essential for its structural use and it is of great importance to the construction industry. Thus, this study aimed to determine the physical and mechanical properties of the wood Amaru - a hybrid of Eucalyptus, developed by Plantar Projects and Forest Products Ltda. In order to determine the properties of Amaru, round samples were used, which were provided to the Laboratory of Wood and Wooden Structures of the School of Engineering of São Carlos, University of São Paulo - LaMEM / EESC / USP. For the characterization of the physical properties, the apparent specific gravity and moisture content of the samples were determined. To the mechanical characterization, the following properties were evaluated: strength and stiffness in compression, strength and stiffness in bending, shear and tension. The procedures of the tests performed in this study were done according to the recommendations of the Brazilian Wood Standard ABNT NBR 7190:1997. The specimen used were confectioned in actual dimensions, according to as those used in the construction system proposed by Plantar. The results obtained from the tests performed showed that the mechanical properties approached the values proposed by the Wood Standard NBR 7190. The visual grading was important to provide a primary idea about the failure modes to be obtained from the tests performed. The bending test showed the modulus of elasticity (MOE) and Modulus of Rupture (MOR), which resulted in 15822 MPa and 101,7 MPa, respectively. The compression test resulted in values Ec0,m and fc0, 15698 MPa and 50,7 MPa. The tensile strength (ft0) of this hybrid was calculated and its value obtained was 60,8 MPa. The shear strength (fv0) was 8,2 MPa. The results obtained from the tests are the basis for engineers and architects to design structures using wood species Amaru

Análise dos fatores de desempenho do ENADE: estudo parao curso de engenharia de produção mecânica

This work has the propose to discuss the National Examination Performance of students for the course in Production Engineering , from 2005 up to 2011, subsidies are shown how this came about assessment and how the course has been evaluated in recent years . Compares higher education from public and private universities in Brazil and is also discussed how important a good performance in the exam. Qualitative and quantitative surveys were conducted at different times that the work that enables a critical analysis of the examination , the institution and also the students themselves , so the list is the main motivators for the exam and also what should be done to obtaining good results in academic performance. Motivators for the exam has highlighted its importance is paramount and the consent of all involved from the beginning of the course to ensure that the examination is compulsory for all graduates of undergraduate manufacturing engineering in Brazil

Estudo de cerâmicas avançadas para fins de blindagem balística

The research involving new materials has always been considered as a differential in the development of a technology company. This occurred naturally since ancient times, often motivated by reasons of a certain age, where the most common material used was also the name of your time and may be cited as an example the Bronze Age, and later was the Iron. Currently, the use of firearms are they used in resolving conflicts between countries, or a more equivocal, as an instrument of social banditry make innovations in the area of shielding welcome, whether for personal use, in the form of vests or vehicle such as cars, tanks and even aircraft. In this context, is a Silicon Carbide Ceramic, with low density and high hardness. Thus, the aim of this study is the evaluation and comparison of these materials, seeking to improve their properties by means of additives such as boron and silicon metal and amorphous YAG. For this work, the specimens were pre-shaped by means of uniaxial later to be referred for isostatic pressing and sintering. The maximum percentage for each additive was 5%, except for the YAG whose percentage was 8.2% (mass percentage). All compositions were subjected to the same tests (x-ray diffraction, apparent density, optical microscopy, Vickers hardness, scanning electron Microscopita), so that one could draw a comparison between the materials under study, samples that showed better mechanical properties and micro structural, related here by hardness testing and microscopy (optical and SEM) were the silicon carbide doped with YAG and alumina samples, demonstrating the potential of these materials for ballistic protection. Other compositions have high porosity, which is highly undesirable, since in order to harmful influences on the mechanical properties discussed below

Introdução de Lentinulaedodes (Shiitake) e Pleurotusostreatus (Shimeji) em bagaço de cana termo explodido para diminuição da toxicidade

Ethanol production has gained great prominence in the investment new renewable energy sources and Brazil is among the leaders of production. However, this activity generates large amounts of waste being the largest volume of the sugar cane bagasse. For this reason looking up ways to use this material as burning for energy production and composition of forage in the diet of ruminants, however there are difficulties to use this production for this last one. This paper proposes a microbiological treatment with Lentinula edodes and Pleurotus ostreatus in order to enable the bagasse in ruminant feed composition in order to be used more noble than their burning. After treatment with the fungus, tests were performed for quantifying crude protein by the method of Kjeldhal. It was verified that the protein content in the pure bagasse was 1.0% after fermentation the protein content was 4.2% with L.edodes and 4.9% with P. ostreatus. To evaluate the protein quality of the product fermented by L. edodes and P. ostreatus was applied microbiological method for growth of Enterococcus zimogenes verifying that after fermentation the protein quality was 76 and 27.4% with L. edodes and P.ostreatus, respectively, compared with casein. The quantification of amino acids showed significant improvement of protein with altered amino acid profile with treatments of fungos. About of DQO and BOD were also found considerable improvement besides considerable drop in toxicity as measured by acute toxicity test with Daphinia similis

Expressão de defensinas por membranas corioamnióticas de gestações pré-termo complicadas por corioamnionite

As membranas corioamnióticas são barreiras mecânicas contra a ascensão de microrganismos e possuem papel fundamental no sistema imune inato. Quando é invadida por microrganismos apresenta corioamnionite aguda, que é a infiltração das membranas fetais por leucócitos polimorfonucleares. Entretanto as membranas têm efeito inibitório sobre o crescimento de muitas bactérias, em parte, pela produção de defensinas. Quantificar a expressão de defensinas (HBD1, 3 e 4) por membranas corioamnióticas de gestações complicadas por corioamnionite. Foram incluídos no estudo 40 fragmentos de membranas corioamnióticas, com diagnóstico histológico de corioamnionite, provenientes de gestações complicadas por rotura prematura de membranas pré-termo (RPM-PT) e/ou trabalho de parto prematuro (TPP) que apresentaram parto prematuro como desfecho gestacional, constituindo o grupo estudo (G1). Como grupo controle (G2), foram avaliadas 40 membranas corioamnióticas, com ausência de corioamnionite e pareadas pela idade gestacional ao grupo estudo. Fragmentos das membranas corioamnióticas foram encaminhados à análise histopatológica para confirmação de corioamnionite histológica. Outros fragmentos de 1cm2 das membranas foram acondicionados em RNA later e submetidos à extração de RNA total. Após a extração do RNA, as amostras com concentração entre 0,02 e 0,2μg/ μL de RNA foram submetidas à obtenção de cDNA e posterior utilização na quantificação da expressão de defensinas pela técnica da PCR em tempo real empregando-se o sistema TaqMan® Gene Expression Assays. Em relação às variáveis sócio-demográficas, as porcentagens de mulheres que referiram união estável, cor branca e hábito tabagista foram similares entre os grupos estudados. Em relação às variáveis obstétricas não houve diferença estatisticamente significativa entre os grupos G1 e G2... (Resumo completo, clicar acesso eletrônico abaixo)

Análise da curva de resfriamento da liga de alumínio AA 356

It is very important to study the macrostructure of a material in the crude state of solidification due to influence the mechanical properties, as well as the study of their cooling curve. In the present work was to study the alloy AA 356, its macrostructure and its cooling curve. The material was cast in two different molds, a sand and other metallic. In this paper we study the differences in its macrostructure and its cooling curves. In macrostructure can observe the absence of the three zones of solidification and the presence of large pores because of moisture in the sand. In the sample taken from the metal mold can observe the three zones of solidification: a coquilhada, columnar and equiaxed

Flexão e análise dinâmico-mecânica de compósitos 5HS e NCF com resina epóxi monocomponente produzidos por RTM

In order to study resin distribution and homogeneity of composite laminates manufactured by RTM, it was used CYCOM 890 monolithic toughened epoxy as a matrix with two different configurations of intermediated modulus (IM) carbon fibers: Satin Weave (5HS) and non crimp fabric (NCF). The injection parameters were defined based on Thermo Gravimetric Analysis (TG), Differential Scanning Calorimetry (DSC) and rheological analysis. After processing the material, the resin/fiber impregnation was studied using ultrasonic test, Thermo Gravimetric Analysis, Differential Scanning Calorimetry, Dynamic Mechanical Analysis (DMA) and flexural tests. Therefore, it was able to observe an internal residual stress during the cooling process in both laminates, higher in the composite using NCF fabric due to the lack of symmetry, although a good proportion of fiber/matrix has been verified by the lower values of flexural modulus deviation. The DMA enabled the visualization of glass transition and its association with the inter and intra molecular interaction and movement, in which the NCF composite presented better permeability due to the lowest temperature of glass transition, when compared to the Satin Weave composite

Do termo à estruturação semântica: representação ontológica do domínio da Nanociência e Nanotecnologia utilizando a Estrutura Qualia

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

Estudo dos fatores de virulência e resistência à oxacilina em Staphylococcus spp. isolados de aspirado traqueal de pacientes em ventilação mecânica internados em UTI

Patients that are mechanically ventilated in ICUs are constantly exposed to different pathogens, which present multiantibiotic resistance. Among these microorganisms, is MRSA (Meticillin-Resistant Staphylococcus aureus) considered to be a therapeutic challenge due to its resistance to β-lactam antibiotics. Therefore, this study proposed to identify species of Staphylococcus spp. isolated from mechanically ventilated patients in ICU, the gene mecA detection and the genes of the enterotoxins A (sea), B (seb), C (sec-1) and D (sed) in samples of S. aureus, as well as the phenotypic resistance determination to oxacillin using the disc-diffusion method with discs of oxacillin and cefoxitin. The samples collection occurred during in a period of 19 months, obtaining samples from 232 patients. A percentage of 39% (70) of Gram-positive cocci were found; which 82,8% (58) were identified as Staphylococcus spp,. among these, 75,8% (44) corresponded to S. aureus species and 47,7% were identified as MRSA. It was found resistance to both drugs in 31,8% of the S. aureus samples, 16 (36,3%) had the gene sea and 11 (25%) had the sec-1 gene. Among the coagulase-negative staphylococci obtained, the species most found was S. epidermidis, corresponding to 43% (6). The results revealed that one of the most important etiologic agents of VAP amid the Gram-positive cocci is the species S. aureus, with special attention to MRSA. The presence of enterotoxins genes in S. aureus did not showed determinant role in VAP, but the presence of these superantigens can contribute worsening the patient’s prognosis, since they are associated with intense inflammatory response