Estudo do efeito do modificador Al-Sr no tratamento de modificação do eutético da liga AA356

The AA356 alloy is an alloy widely used in the automotive industry and aerospace due to its excellent mechanical properties. Refining the structure of eutectic silicon aluminum alloys is a fairly common practice in the foundry through treatment known as modification. This can be achieved by modifying agent adding chemicals such as contained in groups I and IIa of the periodic table and rare earths (europium, céreioi, praseodymium, neodymium, etc.). Has the ability to modify the structure of the eutectic, but only sodium and strontium produce an action modifier strong when used in low concentrations. The modifying effect of the shafts turn silicon into a fibrous form and branched surrounded by metallic matrix in the form of a composite structure that has the highest limit of tensile strength, ductility and machinability. In this work will be obtained ingots with and without the modifier type Al-10% Sr, made in sand molds and are generated and analyzed cooling curves and also the study of the macrostructure and microstructure of the solidified material. It was found that by adding the Al-Sr made shorten the solidification time and lower the grain size

Ensaio de ligações de estruturas de madeira por chapas com dentes estampados em quatro espécies da família leguminosas

In the last years, the use of industrialized systems of lattice structures of wood as an alternative in the construction processes, is becoming more popular in Brazil, mainly for their commitment to the environment.The industrialized system of wooden lattice structures consists in a production of lattice structures, composed of pieces of wood where their mechanical connections are made with the sheet multi-toothed connectors (CDE).Among the many challenges to make this system competitive, the whole system of the connections between the pieces of wood not only must show functionality, but also speed, strength, versatility and economy. Referenced at Brazilian Standard for Wood Structures (NBR 7190/1997 - Project of timber structures) the sheet multi-toothed connectors, are analyzed using three test methods: tensile strength parallel to grain, tensile strength normal to the fibers and shear strength, all of them in two positions, αCH0=0o e αCH0=90o to four types of wood: Angelim (Vatairea heteroptera Ducke); Red-Angico (Parapiptadenia rigida (Benth) Brenae); Garapa (Apuleia leiocarpa (Vog.) Macbr) and Jatoba (Hymenaea stilbocarpa Hayne), belonging to the Leguminosae family and founded in several regions of Brazil.The purpose of this manuscript consists to analyze the mechanical connections with the sheet multi-toothed connectors through tests from NBR7190/1997

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

Preparação e caracterização da casca de banana prata particulada para aplicação com reforço em compósito de matriz de PEAD

The waste, exaggerated and incorrect disposal of biomass are common practices in modern times where everything is disposable. However the growing concern with the nature and the environment compel man to give nobler destinations for these products through sustainability and recycling of waste. Banana peel is a residual biomass, which is not consumed. It generates tons of waste per week in São Paulo city. This trash is disposed in dumps and landfills, which could be reduced by using it as reinforcement in natural composites. The high density polyethylene (HDPE) is a polymer derived from the ethylene polymerization and is easily recycled. Which makes it a sustainable material. In the present work characteristics of the natural composite composed with banana peel and high-density polyethylene were studied. It was noted that removing the lignin present in the banana peel, the fiber introduces a significant improvement in thermal resistance. The preparation of composite was made with a ratio of 5% and 10% of reinforcement in comparison with polymeric matrix mass. Composites were thermally, mechanically and microscopically characterized. The addition of fiber in the polymer increased the mechanical strength of the composite. The fiber surface treatment with distilled water removed the amorphous material present in the fibers, improving significantly thermal stability and increasing crystallinity of the celullose. The addition of 5% fiber in mass to the polymer increased significantly the tensile strength and elasticity modulus for the composite. With 10% of fiber addiction there were also an improvement when compared with pure HDPE, but when compared with 5% composite the mechanical properties are slightly lower. This may be due to the fiber particle size, which are small and eventually become a hub of tension ... (Complete abstract click electronic access below)

Avaliação da tenacidade em um aço microligado, grau API, para aplicação em linhas dutoviárias de petróleo e gás

In order to study the mechanical properties of micro alloyed steel API 5L X70, a material used to manufacture pipes for pipeline transportation lines for use in oil and gas, a study was made of toughness, tensile strength, impact strength, hardness and microstructure steel. To perform these various tests were made where they can acquire the characteristics of the material. Were performed at the Faculty of Engineering in Guaratinguetá in the Department of Materials and Technology and the tensile tests, Charpy impact test, metallography and hardness testing of material API 5L X70, all tests were done with the help of technical laboratories. With these data can be an analysis of the material about his tenacity, his toughness and fragility, its hardness, its yield strength and its maximum voltage. After being asked the analyzes discussed the results showed that the micro alloyed steel API 5L X70 steel is a very tenacious, it absorbs impact energy of 300 Joules though without a break for the full body of evidence showing its tenacity

Estudo da influência da adição de resíduos de óleo em concretos para aplicação em pavimentos

Pós-graduação em Engenharia Civil - FEIS

Cimentação de coroas com fosfato de zinco sobre munhões de liga de titânio, irradiados ou não por laser

By means of tensile strength, NiCr total crowns were removed from machine-made conical abutments composed by an Ti-6Al-4V alloy. In a total of 20 abutments, 10 were used with it surface presenting high smoothness and 10 abutments had its surfaces modifi ed by laser both cemented with zinc phosphate. The mechanical test was performed at a MTS 810 universal machine adjusted to a speed of 0.5 mm/m. The statistical analysis was done by Levene’s test, which showed homogeneity of variances among groups (F =2.21; p < 0.1). “Student t test” showed that signifi cant differences were found between groups. The modifi cation of the abutment surface through laser caused an increase in pull-out resistance of crowns cemented with zinc phosphate from 430.66 N to 1.514,87 N.

Resistência à tração de coroas de NiCr cimentadas sobre munhões de liga de titânio, com 4 diferentes tipos de cimentos

In this work of tensile strength was evaluated the efficacy of 4 cements (S. S. White zinc phoshate, Ketac Cem Easymix glass ionomer, RelyX Luting 2 composite resin/glass ionomer and Panavia 21 TC special acrylic resin) used to fix NiCr crowns to usinated titanium alloy abutments. Were used 40 abutments distributed in groups of 10 elements, to each material. The mechanical essays were developed at a MTS 810 universal machine, adjusted to a 0.5 mm/m velocity. The ANOVA applied to data pointed out the existence of significant differences between groups; the subsequent Tukey´s test (p<0.05) also detected significant differences, except at comparisons of phosphate versus RelyX and phosphate versus Ketac Cem. The better performance was presented by Panavia 21 (1,127.996 N); RelyX (478.197 N) showed itself similar only to phosphate (430.662 N), wich had a performance similar to that of Ketac Cem (227.705 N).

Concreto com adição de cinza de bagaço de cana-de-açúcar

Pós-graduação em Engenharia Civil - FEIS

Desenvolvimento de um novo sistema dinâmico para avaliação da liberação de fármacos

Pós-graduação em Biociências - FCLAS

Aplicação da membrana de látex natural (NRL) como suporte para cultura das células osteogênicas MC3T3-E1 para regeneração óssea guiada (GBR)

Pós-graduação em Biotecnologia - IQ

Equipamento para realização de ensaios de tração confinada e aquecida em geossintéticos

Pós-graduação em Engenharia Civil - FEIS

Resistência de união e microinfiltração em restaurações de resina

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

Efeito de um gel de peróxido de carbamida a 10% sobre a resistência de união de restaurações adesivas à dentina

The present study aimed to analyze the effects of tooth bleaching with 10% carbamide peroxide (CP) gel on the bond strength of resin composite restorations to dentin. Material and Methods: Twenty cavities were prepared on the buccal surface of bovine teeth. After acid etching and application of bonding agent on dentin and enamel, the cavities were restored with composite resin. The specimens were divided into groups according to treatment on the surface of enamel / restoration: G1 - control (no treatment) and G2 (10% PC gel application for 8h/day during 14 days). After this period, the teeth were cut to produce beams with 0.81 mm2 cross-sectional area, which were subjected to microtensile test. The fractures were examined with a stereomicroscope and classified as cohesive in resin or dentin, adhesive, or mixed. Results: The statistical analysis (ANOVA / χ2) revealed that the factor treatment interfered with the bond strength, which was significantly higher for specimens of G2 (p <0.05). Adhesive fractures occurred in most of specimens of both groups with values ranging from 48.3% to 75%. Mixed fractures were the second more frequent in G1 and cohesive resin failure in G2. Conclusion: It was concluded that tooth bleaching with 10% of PC increased the bond strength of adhesive restorations to dentin.

Influence of heat treatment and mechanical cycling on hardness and fracture analysis of Ti35Nb5Zr casting alloy

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