Nonoxidative thermal degradation kinetic of polyamide 6,6 reinforced with carbon nanotubes

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

Avaliação da reação tecidual de uma resina termoplástica em tecido subcutâneo de ratos

Pós-graduação em Odontologia - ICT

Painéis aglomerados fabricados com mistura de partículas de madeiras tropicais

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

A castor oil-containing dental luting agent: effects of cyclic loading and storage time on flexural strength

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

Pre-extrusion aromatization of a soy protein isolate using volatile compounds and flavor enhancers: Effects on physical characteristics, volatile retention and sensory characteristics of extrudates

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A MICROSTRAIN COMPARISON OF PASSIVELY FITTING SCREW-RETAINED AND CEMENTED TITANIUM FRAMEWORKS

Statement of problem. An imprecise fit between frameworks and supporting dental implants in loaded protocols increases the strain transferred to the periimplant bone, which may impair healing or generate microgaps.Purpose. The purpose of this study was to investigate the microstrain between premachined 1-piece screw-retained frameworks (group STF) and screw-retained frameworks fabricated by cementing titanium cylinders to the prefabricated framework (group CTF). This procedure was developed to correct the misfit between frameworks and loaded implants.Material and methods. Four internal hexagon cylindrical implants were placed 10 mm apart in a polyurethane block by using the surgical guides of the corresponding implant system. Previously fabricated titanium frameworks (n=10) were divided into 2 groups. In group STF, prefabricated machined frameworks were used (n=5), and, in group CTF, the frameworks were fabricated by using a passive fit procedure, which was developed to correct the misfit between the cast titanium frameworks and supporting dental implants (n=5). Both groups were screw-retained under torque control (10 Ncm). Six strain gauges were placed on the upper surface of the polyurethane block, and 3 strain measurements were recorded for each framework. Data were analyzed with the Student t test (alpha=.05).Results. The mean microstrain values between the framework and the implants were significantly higher for group STF (2517 me) than for group CTF (844 me) (P<.05).Conclusions. Complete-arch implant frameworks designed for load application and fabricated by using the passive fit procedure decreased the strain between the frameworks and implants more than 1 piece prefabricated machined frameworks.

Adsorção do corante luganil azul por espuma de poliuretano

The industrial development has created many environmental problems that can be observed through the changes in air, soil and water. The pollution of water bodies with compounds present in textile effluents cause beyond the visual pollution, changes in biological cycles, mainly by changing the process of photosynthesis. Due to these environmental implications it is necessary a treatment of livestock manure. The process of adsorption of the dye is a technique that has been successfully employed for effective removal of the color of the effluent. The purpose of this study was to investigate the application of a polyurethane foam plant of castor oil as an alternative adsorbent for removal of dyes in textile effluents. The study was conducted with the dye “luganil azul”, as adsorbent and the foam in a flexible manner and sprayed. It also investigated the influence of pH on the adsorption dye. The kinetic data were obtained, noting that the pH influence on adsorption. Adsorption isotherms of the dye in aqueous solution using the foam in a flexible manner also were determined experimentally.

Aproveitamento de resíduos de laminação da madeira para a produção de painel estrutural

Products derived from wood or engineered products are becoming interesting alternatives to the replacement of solid wood in various applications, from structural components to the furniture industry and packaging. Among these products, there are panels built by strands, particles and fibers, each one having their particular characteristics and potential of use. Since the different types of panels are produced, waste generation is part of the process, and that more technological it is, it still generates losses of raw materials. Based on the need for rational use of raw materials and using almost full of industrially processed wood, It arises the proposal of this work, which seeks to use waste from the lamination, like pieces of strands, broken strands, strands rough, cracked strands to produce panels with structural characteristics of the OSL panel (Oriented Strand Lumber), LSL (Laminated Strand Lumber) and OSB (Oriented Strand Lumber). Besides the use of waste, this paper seeks an alternative to the use of the adhesive, because the industry uses formaldehyde-based adhesives, which over the press, they emit large amounts of formaldehyde, which is very aggressive to humans and environment. The panels made with polyurethane resin based on castor oil and hot-pressed were characterized by physical and mechanical tests according to specifications of European Standard (EN). High values of tensile strength, elastic modulus and density were found in the results of tests. Adding to stable values of swelling and moisture content, the panel studied adds attractive features to the panel market, especially in the civil construction

Obtenção e caracterização de suporte de regeneração óssea de dióxido de titânio

Due to complications caused by metallic implants in the replacement of bone tissue, the biological application of ceramics raised and became a viable alternative. The titania has the ability to promote bone tissue regeneration based on its structure, mechanical and biologically properties compatibility. The present work aims at obtaining and characterization of Titania (TiO2) porous ceramics produced by the polymeric sponge method (replica method). Polyurethane sponge with 10 ppi and 15 ppi (pores per linear inch) were used. The process differentiation is the air blower used to remove excess slurry. The ceramics sponges were dried in an oven, then pre-sintered at 1000 o C and sintered at 1450 o C. The effect of direct sintering at 1450 o C was also assessed. The percentage of solids used to prepare the slurry was 40 to 45% by weight. To increase the surface porosity of the sponge, 20% of starch was added. There was difficulty on controlling the thickness of the slurry layers on the sponge which resulted in the variation of samples mechanical resistance. Despite this, the results obtained are quite promising for the proposed use, indicating that it is possible to obtain titania sponges with an apparent porosity of around 60%, a bulk density ranging from 40 to 47% and a compressive strength resistance – that with better control of layers depositions – can vary from 1 to 4 MPa

Caracterização física e mecânica de compensado produzido com dois diferentes adesivos em duas variações de pressão de prensagem

The adhesives used in the production of engineered boards have been object of study over the years in order to improve the properties of the boards with less energy consumption, lower production costs and reduced environmental impact. In addition to that, process variables may affect the properties of the board. The present study aimed to characterize sheets of plywood, manufactured with two types of adhesives, under two different pressing conditions. The adhesives used for the study were Phenol-formaldehyde and Polyurethane castor oil based. The pressure of pressing was varied in a range from 75 to 160 Bar, in order to verify how they influence the physical and mechanical properties of the board. The tests performed resulted in a conclusion that shows that the moister content of the veneers interferes on the physical and mechanical tests. In general, boards produced with polyurethane resin showed superior physical and mechanical results; although the ones produced with phenol formaldehyde at a pressure of 75 Bar had always equal or higher values, compared to what is found in literature

Análise preliminar para a estimativa da perda de calor sensível de um fluido homogêneo térmico em um reservatório de geometria cilindrica

This work analyzed the loss of sensible heat from one fluid to be considered homogeneous heat distribution on a thermal reservoir with cylindrical geometries composite insulating layers. We studied two thermal reservoirs with a volume of 20 liters, and the first has a layer thickness of 75 mm of expanding polyurethane foam wrapped in the polycarbonate container and the second container has only layer thickness of 5 mm of polycarbonate, as insulation of fluid of the external environment. The experimental results are compared with theoretical results obtained through a calculation script, displayed and detailed during the work development, from the theory of energy balance. The maximum error introduced between the theoretical and experimental results were 3.5% and 1.4% respectively for the Boilers with or without a polyurethane coating

Avaliação do ciclo de vida dos tubos de PVC produzidos no Brasil

Naturally characterizes the human being the interference in the environment to ensure their survival and also convenience. After numerous environmental accidents caused by unbridled pursuit of this goal, the concern about providing for current needs without compromising the ability of the future generations to supply their own, gained space. In order to contribute to sustainable development the Life Cycle Assessment (LCA) was implemented. This tool is based on the concept that if the environmental impacts of a product or service are known, it is possible to take better decisions concerning its environmental aspects. The purpose of this research is to conduct the LCA of polyvinyl chloride (PVC), the world’s second most consumed thermoplastic. The methodology described in NBR ISO 14040 and NBR ISO 14044 was followed. As a result, the LCA of polyvinyl chloride produced in Brazil was obtained, and, therefore, the inventory of the product in question adapted to Brazilian reality. The research can be applied to various studies considering that actions were taken to ensure that it represents the Brazilian reality. Moreover, the procedures were described to guarantee the greatest transparency possible

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

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

Extensometria: estudo das microdeformações ao redor de três implantes de hexágono interno, com posicionamento linear, sob a influência da fundição de coifas plásticas e usinadas

The objective of this in vitro study was quantify the micro strain development around the internal hexagon implants, varying the type of prosthetic coping. For This reason, three implants of internal hexagon were inserted into one polyurethane block in line placement. Microunit abutments were screwed onto the implants. Tangentially the implants were bonded the strain gauges, two to the center implant. Ten structures, each one containing three copings were cast in Co-Cr alloy, that were divided into groups in the first group, plastic copings were used, and in the second group machined copings were used. The superstructure’s occlusal screws were tightened onto Microunit abutments with 10 Ncm torque, the magnitude of micro strain was recorded. The mean values of each strain gauge of each plastic copings were 363,37 ± 237,66 and the machined copings were 338,12 ± 223,01. The data were analyzed statistically by t- Student test. No statistically significant difference was found between the prosthetic copings (p= 0,867). It was concluded that to internal hexagon implants in line placement, the type of copings presented similar magnitude of micro strain after prosthetic occlusal screw was tightened