935 resultados para osmotic shrinkage


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Nowadays, bamboo is being studied because of their strength properties according with their specific mass and speed of growth, which makes it an important alternative as a new resource that will help reduce pressure on forests and helpping them favoring the minimization of uncontrolled deforestation in many regions of Brazil. This study aimed, in general, to analyze physical and mechanical properties of the material with the divulgation of its potential for industrial application. To do so, in this research were determined in relation to the physical properties, moisture content, dimensional stability and the apparent densities and the mechanics and basic, just a tension parallel to grain, in order to observe the interference of various kinds of treatments (chemical, thermal and natural) on the strength and modulus of elasticity in this request. The species used was the Guadua angustifolia, a species native of Brazil. All tests were performed at Universidade Estadual Paulista - Campus Experimental Itapeva in the laboratory of Materials Properties. The methodology used for testing of moisture, density and tension parallel to grain were based on NBR 7190/1997 for the wood, and dimensional stability tests were based on much the same as in COPANT 462/1972 (South American) . The preservative treatments conducted followed the recommendation of each manufacturer. The values obtained in tests of physical properties were satisfactory especially with respect to density and dimensional stability analyzed by the coefficient of anisotropy, showed that, compared to wood, excellent quality for the shrinkage test, obtaining a coefficient of 1.2. With respect to parallel tensile tests to fibre results showed, in most cases, that test specimens with the presence of us have lower values of resistance and modulus of elasticity when compared with those without us. In the treatment of thermal-treatment there was an apparent treatment there was an apparent increase in...

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This project has several objectives: To determine medium values and variations of the density, porosity, humidity, shrinkage volume and the coefficient of mass attenuation of gamma radiation of 59,6 keV of the radioisotope 241Am, using samples of equine radio, in growth and adult. The samples of bones were supplied by the Department of Pathology of University of Veterinary Medicine and Zootechnics - UNESP campus Botucatu. Bones of the paws front left of two males were used. Of each bone ten samples were removed. Those samples were prepared to just obtain compact bony fabric, being submitted to the rehearsal of determination of the density by the immersion method in water and determination of the coefficient attenuation lineal for the method of attenuation of the radiation of the 241Am, also obtaining your humidity content. Still, they were obtained new samples starting from the ground samples and verified the density of the particles present in that, obtaining the medium value of the coefficient of mass attenuation. The results showed the medium values and significant statistical variations of the density, porosity, humidity, shrinkage volume and coefficient of mass attenuation of gamma radiation of 59, 6 keV of the radioisotope 241Am in the samples, establishing some relationships between of the certain physical parameters with biological aspects and possible existent influences between them

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The present work aims to study the characteristics of the alloy Al - 7 % Si - 0 , 3Mg ( AA356 ) , more specifically characterize the macrostructure and microstructure and mechanical properties of the alloy ingots AA356 obtained in metal molds and sand molds for power studying the structures through the difference of cooling rates . This alloy is explained by the fact of referring league has excellent combination of properties such as low solidification shrinkage and good fluidity, good weldability , high wear resistance , high strength to weight ratio, has wide application in general engineering , and particularly in the automotive and aerospace engineering . In this work we will verify this difference in properties through two different cooling rates . We monitor the solid solidification temperatures by thermocouples building with them the cooling curve as a tool that will aid us to evaluate the effectiveness of the grain refining because it achieved with some important properties of the alloy as the latent heat of solidification fraction the liquid and solid temperatures, the total solidification time, and identify the presence of inoculants for grain refinement. Thermal analysis will be supported by the study of graphic software “Origin “will be achieved where the cooling curve and its first derivative that is the cooling rate. Made thermal analysis, analysis will be made in macrographs ingots obtained for observation of macrostructures obtained in both types of ingots and also analysis of micrographs where sampling will occur in strategic positions ingots to correlate with the microstructure. Finally will be collecting data from Brinell hardness of ingots and so then correlating the properties of their respective ingots with cooling rate. We found that obtained with cast metal ingots showed superior properties to the ingots obtained with sand mold

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Pós-graduação em Engenharia Mecânica - FEG

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Pós-graduação em Ciência Florestal - FCA

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

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Pós-graduação em Genética e Melhoramento Animal - FCAV

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Posterior teeth restorations have changed the contemporary treatment philosophy influenced by the aesthetic demand of patients, progress of adhesive material science and techniques for preservation and rehabilitation of affected teeth by dental caries and trauma. The development of Onlay restorations with semi-direct technique in endodontically teeth treated aims to preserve the remaining surfaces, to reduce the possibility of fracture and polymerization shrinkage. In addition, better restoration adaptation and marginal seal, resistance to wear and dimensional stability are achieved. This case reports the rehabilitation of an endodontically treated permanent maxillary first molar in a 13 years old- patient who attended the Araraquara School of Dentistry, Brazil, using Miris 2 Composite resin with semi-direct technique and obtaining an aesthetic and functional restoration in a single appointment. The fundaments and clinical guidelines of the procedure are detailed, based on the review of the literature that supports this conservative treatment.

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The composite resin is the material of election for direct restorations in posterior teeth currently. The restorative dentistry aims to improve each day the material and facilitate the restorative technique. This paper describes the technique of occlusal matrix made to speed up and preservation the occlusal surface of a first molar tooth affected by caries lesion. A new resin-based composite was used called Silorane, which may be placed in larger increments due the material has low shrinkage and polymerization stress. The use of occlusal matrix associated with a low shrinkage resin composite can simplify the clinical work, and result in a restoration with excellent reproduction of anatomical.

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Pós-graduação em Agronomia (Energia na Agricultura) - FCA

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

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

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The objective of this study was to evaluate the phytotoxicity of Solanum aculeatissimum Jacq. leaves ethanolic extract in seeds germination, development and fixation of Lactuca sativa seedlings. The same study also aimed to assess the mitotic index of lettuce roots meristematic cells, quantification of phenols and total flavonoids and triage by mean of phytochemical testing of the main secondary metabolites classes. Bioassays of germination, development of root and hypocotyl were carried out in Petri dishes using achenes of Lactuca sativa L. cv. 'Grand Rapids' (lettuce). Concomitantly, were evaluated the physico-chemical characteristics (pH, osmotic potential and electrical conductivity), mitotic index, quantification of total phenols and flavonoids and determination of phytochemical profile of the treatments extract. The results obtained in the bioassays demonstrate that the ethanol extract of S. aculeatissimuma presents phytotoxic potential in the development of lettuce seedlings, given that the concentration of 20 mg/ml showed greater inhibition (41% of germination). The extract contains significant amounts of antioxidants, total flavonoid and phenols, where the concentration 1000µg/mL showed higher values (86.50%). Furthermore, it was possible to observe the presence of compounds with allelopathic activity in the phytochemical screening test as coumarins, tannins, terpenes, flavonoids and alkaloids. Given the above it is clear that the ethanolic extract of S. aculeatissimum presents allelopathic substances with phytotoxic activity that can affect the germination and development of other plant species in their natural environment.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)