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Shin M.-S.,Sogang University | Kim J.-K.,Sogang University | Kim J.-W.,Sogang University | Moraes C.A.M.,University of Vale do Rio Sinos | And 2 more authors.
Journal of Industrial and Engineering Chemistry | Year: 2012

Al/Fe 2O 3 nonacomposites have explosive and high exothermic properties by thermite reaction. In this study, Al/Fe 2O 3 xerogel nanocomposites were prepared by sol-gel method and thermite reaction performance was compared with those prepared by physical mixing with sonication. Scanning electron microscopy (SEM) images of Al/Fe 2O 3 xerogel nanocomposites show that network structure of Fe 2O 3 gel covers Al nanoparticles efficiently and this indicates that improvement of thermite reaction performance due to close contact between a fuel and an oxidizer. Optimum mole ratio of Al/Fe was determined to be 2 by thermite reaction performance by differential scanning calorimetry (DSC) analysis. At Al/Fe ratio of 2, thermite reaction enthalpy of the Al/Fe 2O 3 xerogel nancomposite was 991.4J/g, which was higher by a factor of four than that of the nanocomposite prepared by physical mixing. © 2012 The Korean Society of Industrial and Engineering Chemistry.

Mendes Moraesa C.A.,University of Vale do Rio Sinos | Kielinga A.G.,University of Vale do Rio Sinos | Caetanob M.O.,University of Vale do Rio Sinos | Gomesb L.P.,University of Vale do Rio Sinos
Resources, Conservation and Recycling | Year: 2010

Considering that the civil construction segment is responsible for a significant amount of the environmental impact, once it consumes a large amount of natural resources and energy, the incorporation of waste in the process brings sustainable benefits for the companies as well as for society. In addition, the reduction of the useful life of mortar coating related to the lack of adherence to the substrate provokes a large generation of waste, increasing the environmental liability of the respective industry. This study aimed to determine the technical and environmental viability of the incorporation of rice husk ash (RHA) waste in mortar coatings, in order to reduce the consumption of natural resources and improve the conditions of adherence of the cementitious matrix. For this evaluation, mechanical tests were carried out to test the adherence to the substrate, besides a survey of all the processes related to mortar coating production, from natural resources extraction till the application of the product and its consequent impact. Finally it was used the life cycle analysis (LCA) tool to evaluate the environmental issue. The results showed an increase of 100% of bond strength for the mortars with 5% addition of RHA, and it was identified, among the processes surveyed, a smaller number of significant impacts in relation to the mortar with no addition. It is noticed that, for the conditions of this study, the mortars with RHA addition present better technical and environmental performance compared to the usual mortars. © 2010 Elsevier B.V. All rights reserved.

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