ABSTRACT
Due to the continual increase in waste generated from electronic devices, the management of plastics, which represents between 10 and 30% by weight of waste electrical and electronic equipment (WEEE or e-waste), becomes indispensable in terms of environmental and economic impacts. Considering the importance of acrylonitrile-butadiene-styrene (ABS), polycarbonate (PC), and their blends in the electronics and other industries, this study presents a new application of laser-induced breakdown spectroscopy (LIBS) for the fast and direct determination of PC and ABS concentrations in blends of these plastics obtained from samples of e-waste. From the LIBS spectra acquired for the PC/ABS blend, multivariate calibration models were built using partial least squares (PLS) regression. In general, it was possible to infer that the relative errors between the theoretical or reference and predicted values for the spiked samples were lower than 10%.
Subject(s)
Acrylonitrile/analysis , Butadienes/analysis , Electronic Waste/analysis , Plastics/chemistry , Polycarboxylate Cement/analysis , Polystyrenes/analysis , Waste Management/methods , Lasers , Spectrum AnalysisABSTRACT
Devido à importância das coroas de aço em odontopediatria, muitas técnicas operatórias têm sido apresentadas com o objetivo de aumentar sua resistência e adaptaçäo. Uma revisäo de literatura a este respeito será apresentrada
Subject(s)
Humans , Male , Female , Child , Dental Cements/analysis , Tooth Crown/surgery , Dental Restoration, Permanent , Glass Ionomer Cements/analysis , Pediatric Dentistry , Polycarboxylate Cement/adverse effects , Polycarboxylate Cement/analysis , Zinc Phosphate Cement/adverse effects , Zinc Phosphate Cement/analysisABSTRACT
Testou-se a resistência mecânica de sete cimentos dentários nas idades de 7 minutos, 30 minutos e 24 horas. Os testes selecionados foram de resistência ao cisalhamento por puncionamento, compressäo e traçäo diametral. Em linhas gerais o melhor comportamento foi alcançado pelo cimento Fosfato de Zinco, seguido pelo Policarboxilato, Oxido de Zinco e Eugenol e Hidróxido de Cálcio
Subject(s)
Zinc Oxide-Eugenol Cement/analysis , Calcium Hydroxide/analysis , Polycarboxylate Cement/analysis , Zinc Phosphate Cement , Dental Cements/analysis , Dental Materials/analysis , Tensile StrengthABSTRACT
Como resultado de los casos clínicos realizados en la presente tesis; podemos deducir; que las bases cavitarias practicadas con cemento de policarboxilato "DURELON" en cavidades superficiales como prfundas, no presentan ningún tipo de reacción pulpar reversible ni reacción irreversible, Por su tiempo de fraguado se puede realizar la obturación definitiva en una sóla sesión, si no se tiene dudas sobre el diagnóstico, Posee un alto grado de adhesión química alos tejidos duros del diente, Puede ser usado como único material de base cavitaria, aislante térmico, protector pulpar y buen sellador marginal, Sirve para la obturación definitiva en piezas deciduas por su baja solubilidad