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Ribeiro S.P.,Secao de Engineering Quimica | Santiago D.G.,Centro Tecnologico Do Exercito | Dos S. Vianna Jr. A.,University of Sao Paulo
Polimeros | Year: 2012

GAP is an aliphatic polyether that includes hydroxyl groups and highly energetic azide groups. Thus, it is an energetic material that can be used as binder or plasticizing agent in propellants and explosive mixtures. The glycidyl azide polymer (GAP) was synthesized and characterized by direct conversion of epichlorohydrin. GAP was synthesized by reaction of sodium azide, epichlorohydrin, and some extensor alcohols. The investigation focused on the effects of some key reaction parameters including reagent proportions, reaction time and two different solvents. The product was characterized by FTIR, UV, NMR, DSC, elemental analysis, TGA and GPC. The species were also evaluated through molecular weight (GPC), glass transition temperature (DSC), ignition time and sensitivity. Source

De Castro M.S.B.,Centro Tecnologico Do Exercito | Ferreira C.L.,Military Institute of Engineering of Rio de Janeiro | De Avillez R.R.,Pontifical Catholic University of Rio de Janeiro
Infrared Physics and Technology | Year: 2013

Vanadium oxide thin films were grown by RF magnetron sputtering from a V2O5 target at room temperature, an alternative route of production of vanadium oxide thin films for infrared detector applications. The films were deposited on glass substrates, in an argon-oxygen atmosphere with an oxygen partial pressure from nominal 0% to 20% of the total pressure. X-ray diffraction (XRD) and X-ray photon spectroscopy (XPS) analyses showed that the films were a mixture of several vanadium oxides (V2O5, VO2, V5O9 and V2O3), which resulted in different colors, from yellow to black, depending on composition. The electrical resistivity varied from 1 mΩ cm to more than 500 Ω cm and the thermal coefficient of resistance (TCR), varied from -0.02 to -2.51% K-1. Computational thermodynamics was used to simulate the phase diagram of the vanadium-oxygen system. Even if plasma processes are far from equilibrium, this diagram provides the range of oxygen pressures that lead to the growth of different vanadium oxide phases. These conditions were used in the present work. © 2013 Elsevier Ltd. All rights reserved. Source

Filho A.A.M.F.,Centro Tecnologico Do Exercito | Gomes A.D.S.,Federal University of Rio de Janeiro
International Journal of Polymeric Materials and Polymeric Biomaterials | Year: 2010

Sulfonated aromatic polymers generally show high swelling at high proton conductivity. This disadvantage makes many of them unfit for proton exchange membrane applications. Crosslinking of the polymer is one way to overcome this problem. In this study, radiation-induced crosslinking was performed on a sulfonated polysulfone membrane, with doses ranging from 2.5 to 25.0kGy (dose rate: 45Gy/min) using gamma rays from a 60Co source. The pristine sulfonated polysulfones was obtained by mild sulfonation of bisphenol-A-polysulfone with trimethylsilyl chlorosulfonate as sulfonating agent. The proton conductivity of the membranes was characterized by means of electrical impedance spectroscopy techniques. Ion-exchange capacity, degree of sulfonation, water content and chemical stability membrane properties were characterized before and after irradiation. The results show that the mechanical, chemical and thermal stability of the membrane improve after irradiation. The degree of sulfonation and the proton conductivity exhibit a tendency to decrease with increasing irradiation total dose. Source

Cardoso D.R.,Centro Tecnologico Do Exercito | Cardoso T.A.O.,Fundacao Oswaldo Cruz
Ciencia e Saude Coletiva | Year: 2011

Today, bioterrorism is a real threat in the whole world. Considering the actions of bioterrorism by using biological agents capable of promoting great epidemics and overload in the health systems of any city, state or country, the bioterrorism is not only a health professional concern, but government and military also. This article discusses a bibliographical review done in the LILACS, MEDLINE, SciELO and REPIDISCA databases, during the period of 1997 the 2007, the characteristics of related national publications to the bioterrorism, the type of biological agents studied, and the existing knowledge in the country to face a bioterrorism event, in order to feed with information the professionals who will act in first reply to the bioterrorism events and that are essential to reduce the number of victims. Source

Silva G.R.,Military Institute of Engineering of Rio de Janeiro | Borges Jr. I.,Military Institute of Engineering of Rio de Janeiro | Figueroa-Villar J.D.,Military Institute of Engineering of Rio de Janeiro | De Castro A.T.,Centro Tecnologico Do Exercito
Quimica Nova | Year: 2012

Chemical agents are substances used for their toxic effects on humans, animals and plants. The main objective of chemical defense is to develop systems that reduce these effects while minimizing impact on the operational capacity of military troops. In this work, a report on the development of chemical warfare agents since the First World War and their classification is presented. Special attention is given to neurotoxic agents, the most lethal group of chemical agents known to date. Source

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