Sintering Of A Stainless Steel Scrap Mixture With Powder Of The Same Material. A New Technology For Metal Recycling? [sinterização De Uma Mistura De Cavaco De Aço Inoxidável Com Pó Do Mesmo Material. Uma Nova Tecnologia Para A Reciclagem De Metais?]

The reuse of materials has as its main objective to minimize environmental impacts and to rationalize the use of energy chains. In the present work, samples of scraps of 316 stainless steel mixed with powder of the same material were sintered. For this case, the percentage of scrap was varied from zero to 25% in weight, with 5% increases. After compacting, under a pressure of 600MPa, the samples were sintered simultaneously at a temperature of 1473 K. The mechanical behavior of the final product was evaluated through Assays of Transversal Rupture recommended and normalized by the MPIF - Metal Powder Industries Federation. Using Conventional Quantitative Metallography, the analyses of the sintered samples demonstrated regions of intense diffusion, therefore, regions of sufficiently intense sintering. The mechanical resistance of the samples was compared with the mechanical resistance of the sintered stainless steel with no scrap. The results were greater than expected, demonstrating the viability of this new procedure.60195100GHADIRI, M., FARHADPOUR, F.A., CLIFT, R., SEVILLE, J.P.K., Particle characterization size and morfology (1991) The Institute of Metals Series on Powder Metallurgy -An Overview, pp. 56-75. , London, pSTADTLER, W.A., Production of Metallurgy Parts (1989) ASTM, Powder Metallurgy, pp. 449-463. , Ohio, pLENEL F.V. The early stage of the mechanism of sintering, in powder metallurgy for high-performance application. Syracuse University Press, Binghamton, N.Y., p. 119-137, 1972KEMPTON, H.R., Powder systems and applications (1988) ASTM, Metals Handbook, pp. 568-574. , 9 ed, Ohio, pPowder metallurgy - an overview. 1. ed. The Institute of Metals Series on Powder Metallurgy, London, Great Britain, 1991KUCZYNSKI GC. Fundamentals of sinterig theory, in powder metallurgy for high-performance application. Syracuse University Press, Binghamton, N.Y., p.101-117, 1972Metal Powder Industries Federation. Method for determination of green strength of compacted metal powder specimens. Princeton, N.J.,08540, USA, 1985FERRANTE, M., SINKA, V., Tenacidade à fratura dos aços sinterizados, , São Carlos, SP: UFSCKnysser, W.A., Solid State Sintering (1991) The institute of metals series on powder metallurgy - an overview, pp. 45-53. , London, pMetal Powder Industries Federation, Method for determination of green strength of compacted metal powder specimens, Princeton, N.J.,08540, USA,1985THOMPSON, C.B., Lubrication of metal powder (1988) ASTM, Metals Handbook, pp. 190-193. , 9ed. Ohio, USA, pWILYMAN, P.Q., VANDERMEIREN, M., Selection of atmospheres for sintering (1991) The institute of metals series on powder metallurgy - an overview, pp. 208-218. , London,

Qualidade da pastagem nativa obtida por diferentes métodos de amostragem e em diferentes solos na Apa do Ibirapuitã, Brasil Quality of natural pasture evaluated with different methods and soils at the Apa of Ibirapuitã, Brazil

O estado do Rio Grande do Sul apresenta ecossistemas heterogêneos, devido ao grande número de tipos de solo e à variação em altitude e clima, que se reflete na diversidade da composição florística das diferentes comunidades vegetais. A Área de Proteção Ambiental do Ibirapuitã (APA do Ibirapuitã), é a única unidade de conservação federal, representante do bioma campos sulinos no Brasil. O objetivo deste trabalho foi obter informação sobre a qualidade do campo natural oriundo de três tipos de solos predominantes na APA do Ibirapuitã: Basalto superficial, Basalto profundo e Arenito obtidos por três formas de amostragem: Corte de emparelhamento, Simulação de pastejo através de coleta manual e Corte total acima da fração mantilho. Os dados foram coletados mensalmente, no período de outubro/2001 a setembro/2003. A pastagem nativa no solo de Basalto superficial apresenta forragem com qualidade nutricional superior quando comparado ao Basalto profundo e ao Arenito, comprovada pelas diferentes análises de qualidade realizadas. O método de coleta de amostras de forragem de pastagem nativa somente não influencia os resultados da análise de Fibra em Detergente Neutro. Os resultados indicam a simulação de pastejo como um método adequado de amostragem para avaliação da qualidade da pastagem nativa, devido à sua efetividade e facilidade de coleta.<br>Heterogeneous ecosystems are found in the state of Rio Grande do Sul as a consequence of the great number of soil types and variation in altitude and climate. These conditions reflect on the great variety of flora present in the grassland communities. The Area of Environmental Protection of the Ibirapuitã (APA of Ibirapuitã) is the only conservation unit under federal jurisdiction representative of the Campos bioma in Brazil. The objective of this work was to obtain information about the quality of the natural pasture on three types of soils in APA of Ibirapuitã: Superficial Basalt, Deep Basalt and Sandy, using three methods: total monthly accumulation using cages, hand plucking and regular cut. The data were collected monthly between October/2001 and September/2002. The native pasture on Superficial Basalt soil had superior nutritional quality when compared to the others, as seen in the results of different quality analyses. The pasture sampling methods did not influence the neutral detergent fibre content. The results indicate the hand plucking method, as the best for native pasture quality evaluations due to its effectiveness and facility of collection