Tribological characterizations of composites are primarily focused on the evaluation of wear resistance (WR) and/or the coefficient of friction, although roughness of abraded surfaces (RASs) is one of the key factors that also determines tribo-performances. This study is aimed at modeling RAS in conjunction with WR considering experimental results of Al-matrix/alumina composites performed under two-body abrasion following the central composite design method. Influences of different in situ and ex situ parameters on tribo-responses were analyzed and modeled using analysis of variance, the response surface method, and multi-response optimization. The WR of the selected system was maximized at around 15 wt% alumina at which RAS was also the highest. The positive role of reinforcement on WR and its adverse effect on RAS were explained by micro-mechanisms of abrasion.

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A simple, rapid and effective solvent extraction separation of rare earth elements has been developed for their determination in geological samples such as rock, soil and core samples by inductively coupled plasma optical emission spectrometry.

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A simple and rapid solid phase extraction (SPE) procedure has been developed for the extraction and determination of uranium in water samples. The method is based upon the adsorption of uranium(VI)-2,3-dihydroxynaphthalene complex on microcrystalline naphthalene at the pH range 10 -12 in the presence of a counter cation cetyltrimethylammonium ion. The solid mass consisting of uranium-2,3-dihydroxynaphthalene-CTA complex and naphthalene is ignited in the furnace at a temperature of 700 C for 1 h and then digested in dil. HNO3 solution. Uranium is then determined by LED fluorimetry using fluorescence enhancing pyrophosphate buffer. The effects of different variables like pH of the solution, reagent concentrations, counter cations, stirring time, interfering ions etc. have been investigated thoroughly for the quantitative recovery of uranium. The accuracy of the developed method has been ascertained by standard addition method as well as conventional pellet fluorimetry method involving co-precipitation of uranium using aluminum phosphate as a carrier.

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