﻿<?xml version="1.0" encoding="utf-8"?><rss version="2.0"><channel><title>Advances in Materials Science and Engineering</title><link>http://www.hindawi.com</link><description>The latest articles from Hindawi Publishing Corporation</description><copyright>&amp;#169; 2008, Hindawi Publishing Corporation. All rights reserved.</copyright><item><title>Thermal Arrest Memory Effect in Ni-Mn-Ga Alloys</title><link>http://www.hindawi.com/GetArticle.aspx?doi=10.1155/2008/659145</link><description>Dilatation characteristics were measured to investigate the thermal arrest memory effect in Ni53.6Mn27.1Ga19.3 and Ni54.2Mn29.4Ga16.4 alloys. Interruption of the martensite-austenite phase transformation is connected with the reduction of the sample length after thermal cycle. If a total phase transformation took place in the complete thermal cycle following the interruption, then the sample length would return to its original length. Analysis of these results has shown that the thermal arrest memory effect is a consequence of a stress-focusing effect and shape memory effect. The stress-focusing effect occurs when the phase transformation propagates radially in a cylindrical sample from the surface, inward to the center. Evolution and release of the thermoelastic deformations in both alloys during heating and cooling are analyzed.</description><Author>A. Rudajevova</Author><copyright>&amp;#169; 2008, Hindawi Publishing Corporation. All rights reserved.</copyright></item><item><title>Characterization and Catalytic Performance of Niobic Acid Dispersed over
                         Titanium Silicalite</title><link>http://www.hindawi.com/GetArticle.aspx?doi=10.1155/2008/345895</link><description>Niobic acid, Nb2O5&amp;#x022C5;nH2O, has been supported on the titanium silicalite by impregnation method. The obtained materials 
were characterized by X-ray diffraction, infrared, and ultra-violet&amp;#8212;visible diffuse reflectance 
spectroscopy, temperature programmed reduction, pyridine adsorption, and field emission scanning electron
 microscopy techniques. It was demonstrated that the tetrahedral titanium species still retained after impregnation
  of niobic acid. The results revealed that niobium species interacted with hydroxyl groups on the 
  surface of TS-1. The niobium species in the catalysts are predominantly polymerized niobium oxides species 
  or bulk niobium oxide with the octahedral structure. All catalysts showed both Br&amp;#248;nsted and Lewis acid 
  sites. The catalysts have been tested for epoxidation of 1-octene with aqueous hydrogen peroxide. It was found 
  that the presence of niobic acid in the catalysts enhanced the rate of the formation of epoxide at the initial 
  reaction time. Diol as a side product was also observed due to the acidic properties of
 the catalysts.</description><Author>Didik Prasetyoko, Zainab Ramli, Salasiah Endud, and Hadi Nur</Author><copyright>&amp;#169; 2008, Hindawi Publishing Corporation. All rights reserved.</copyright></item><item><title>Coesite Formation at Ambient Pressure and Low Temperatures</title><link>http://www.hindawi.com/GetArticle.aspx?doi=10.1155/2008/406067</link><description>Partial crystallization of silica xerogel in the form of coesite has been obtained at 
                  low-pressure conditions and temperatures of &amp;#x223C;565&amp;#x2218;C, in samples containing chlorophyll aggregates dispersed in amorphous silica. Silica xerogel 
samples were prepared by the sol-gel method using an ethanol:H2O:TEOS molar ratio of 4:11.6:1 and loaded with extracts from frozen spinach leaves. The silica
 xerogel microstructure of the powders was studied as a function of annealing temperature. It was found that 
 partial crystallization of the glass matrix in the form of coestite was obtained
  at lower pressure than those specified by the phase diagram. Chlorophyll aggregates were added to the 
  starting solutions which, upon thermal treatments, form small colloidal particles in the glass matrix. The 
  presence of coesite is corroborated by the Rietveld refinement method.</description><Author>J. R. Mart&amp;#237;nez, A. V&amp;#225;zquez-Dur&amp;#225;n, G. Mart&amp;#237;nez-Casta&amp;#241;&amp;#243;n, G. Ortega-Zarzosa, S. A. Palomares-S&amp;#225;nchez, and Facundo Ruiz</Author><copyright>&amp;#169; 2008, Hindawi Publishing Corporation. All rights reserved.</copyright></item></channel></rss>