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

Crescimeno de apatita na superfície da liga Ti-7, 5Mo empregando tratamento higrotérmico

The objective of the present work was to evaluate surface of experimental alloy Ti-7.5Mo after hydrothermal treatment. Ingots were obtained in arc melting furnace under an argon atmosphere and then homogenized under vacuum at 1100ºC for 86.4 ks to eliminate chemical segregation and after cold worked discs were cutting and grinding. For surface treatment, samples were immersed in a container with NaOH aqueous solution 5M, autoclaved, washed with distilled water. Followed, samples were heat treated and they were soaking in 5xSBF to form an apatite layer on the surface. Surfaces were investigated by, scanning electron microscopy, X-Rays powder diffraction, atomic force microscopy and contact angle, in order to evaluate the wettability of the alloy surface. The results were compared with our previous studies using the group of chemical surface treatments and results shows better condition is 120 minutes in the autoclave

Caracterização da liga do sistema binário Ti-15Mo para aplicações biomedicas

As they have excellent mechanical properties, corrosion resistance and biocompatibility, much research has been conducted with respect to biomedical applications of titanium alloys. This work aims to study the experimental system binary alloy Ti-15Mo, in the raw state of fusion and heat treatment after homogenization, solubilization and calcination (simulating conditions employed for nanotube growth) targeting biomedical applications. Samples were obtained by casting the components in an electric arc furnace with inert atmosphere of argon. After obtaining the alloy, it was heat treated at three different heat treatments, namely homogenizing, calcining and simulation solubilization. The phases present were analyzed by X-ray diffraction, optical microscopy and microhardness testing

Caracterização funcional da proteína XAC1201 envolvida na patogenicidade de Xanthomonas citri subsp. citri

Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV

Mediadores da via intrínseca da morte celular programada relacionados à infecção in vitro pelo herpesvirus bovino tipo 5

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

Teorema de Riemann-Roch, morfismos de Frobenius e a hipótese de Riemann

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

O imaginário sertanejo no Romance d‘A Pedra do Reino e o príncipe do sangue do vai-e-volta: memória e invenção em uma imagística quadernesca

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

O estatuto lexical das preposições sob e sobre

This paper describes the prepositions sob and sobre in the Functional Discourse Grammar framework (HENGEVELD; MACKENZIE, 2008) aiming at checking their lexical or grammatical status on the basis of classification criteria postulated by Keizer (2007). The following aspects point to their lexical status : (i) they consist of an Ascription Subact; (ii) they contain a specific content on the vertical axis signaling inferiority and superiority position in relation to a limit; (iii) they are not required by any predicate, but they are predicates by themselves, which require complementation by an argument playing Reference semantic function; (iv) they may be combined with de, em, para and por; which are genuine grammatical prepositions; and, finally, (v) they are not subjected to any phonological process of reduction and fusion.

Crescimento de apatita na superfície da liga Ti-25Ta empregando dois tipos de tratamento de superfície: biomimético e deposição de polímero por eletrofiação

Titanium and its alloys has been widely used as materials for metallic biomaterials implants are usually employed to restore the hard tissue function, being used for artificial joints and bones, synthetic plates, crowns, dental implants and screws . Objective of this work was the surface modification of Ti-alloy 25Ta from biomimetic surface treatment of employment and deposition of polymer by electrospinning. The league was obtained from the fusion of the pure elements in the arc furnace with controlled atmosphere. The ingots were subjected to heat treatment, cold forged and sectioned discs with 13 mm diameter and 3 mm thick. Two surface treatments was evaluated, biomimetic and electrospinning with PCL fiber. The biomimetic treatment was performed involving alkaline treatment for three molarities 1.5M, 3M and 5M with immersion in SBF. The electrospinning was performed using PCL polymer alloy surface after the alkali treatment Ti25Ta 1M. For this group the polymer coated surfaces were immersed in calcium phosphate containing solution for immobilization of apatite. The results were compared with previous studies using surface treatment group to verify hydroxyapatite formation on the sample surface and it is concluded that the best condition is biomimetic treatment with 5M alkali treatment and heat treatment at 80 ° C for 72 hours

Estudo da influência do agente nucleante )ALTi5%B1%) na microestrutura de chapas AA8011 obtidas por lingotamento contínuo

The aluminum includes several properties with excellent relation between weight and mechanical resistance. With technological advances, increasingly demand the development of new alloys and other production processes in order to reduce the cost of production and insert these new alloys in broader applications. The process of continuous caster (TRC promoted the unite of the aluminum smelting process with the first stage of rolling, making it most economical through the merger these two phases besides transform the continuous casting process. The AA8xxx series is one of the most versatile aluminum alloys and the most often used in continuous caster process provided a great potential application in the market. In order to further, optimize the process it is necessary to increase awareness of the aluminum solidification phenomena associated with the addition of grain refiner, and control of some aluminum production parameters in the process (production rate, metal temperature, etc.). In this study, AA8011 alloy samples were taken in the raw state obtained by the continuous casting process. The samples were laminated to a thickness of 7mm during the process itself and analyzed at three points along its width by microstructural analysis throughout its thickness, the variation rate of addition of the grain refiner in order to assess the influence of this addition with crystallographic formation and some formation of intermetallic precipitates during the solidification. Through this work, it was possible to improve the knowledge related to the addition of refiner with the monitoring of these production processes

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

Estudo de tensões residuais em juntas soldadas utilizando o método dos elementos finitos

Pós-graduação em Engenharia Mecânica - FEG

Incorporação da apatita na superfície da liga Ti30ta empregando tratamento alcalino associado à eletrofiação de fibras de PCL

Pós-graduação em Engenharia Mecânica - FEG

Obtenção e caracterização de compósitos nanoestruturados de poli(sulfeto de fenileno) reforçados com nanotubos de carbono

Pós-graduação em Engenharia Mecânica - FEG

As memórias de crónica de una muerte anunciada

Pós-graduação em Estudos Literários - FCLAR