http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2013 , Hindawi Publishing Corporation . All rights reserved. Tue, 07 May 2013 11:35:13 +0000 http://www.hindawi.com/journals/composites/2013/539060/ Thin film polystyrene composite scintillators containing and organic fluors have been fabricated and tested as thermal neutron detectors. Varying fluorescence emission intensities for different compositions are interpreted in terms of the Beer-Lambert law and indicate that the sensitivity of fluorescent sensors can be improved by incorporating transparent particles with refractive index different than that of the polymer matrix. Compositions and thicknesses were varied to optimize the fluorescence and thermal neutron response and to reduce gamma-ray sensitivity. Neutron detection efficiency and neutron/gamma-ray discrimination are reported herein as functions of composition and thickness. Gamma-ray sensitivity is affected largely by changing thickness and unaffected by the amount of in the film. The best neutron/gamma-ray discrimination characteristics are obtained for film thicknesses in the range 25–150 μm. Andrew N. Mabe, John D. Auxier II, Matthew J. Urffer, Stephen A. Young, Dayakar Penumadu, George K. Schweitzer, and Laurence F. Miller Copyright © 2013 Andrew N. Mabe et al. All rights reserved. Sun, 28 Apr 2013 15:56:59 +0000 http://www.hindawi.com/journals/composites/2013/162657/ This paper presents an analytical and experimental investigation of cure cycle effect on carbon-fiber reinforced high-temperature polymer composite structures molded by vacuum assisted resin transfer molding (VARTM). The molded composite structure consists of AS4-8 harness carbon-fiber fabrics and a high-temperature polymer (Cycom 5250-4-RTM). Thermal and resin cure analysis is performed to model the cure cycle of the VARTM process. The temperature and cure variations with time are determined by solving the three-dimensional transient energy and species equations within the composite part. Several case studies were investigated by the developed analytical model. The same cases were also experimentally investigated to determine the ultimate tensile strength for each case. This study helps in developing a science based technology for the VARTM process for the understanding of the process behavior and the effect of the cure cycle on the properties of the molded high-temperature polymer composites. Ahmed Khattab Copyright © 2013 Ahmed Khattab. All rights reserved. Wed, 17 Apr 2013 10:24:33 +0000 http://www.hindawi.com/journals/composites/2013/286534/ The aim of this work was to study the activity of several ionic liquids (alkylimidazolium salts) that are used to improve the dispersion of coagent particles in peroxide-cross-linked hydrogenated acrylonitrile butadiene elastomer (HNBR). Hydrotalcite grafted with monoallyl maleate was applied as a coagent for the HNBR vulcanization. In this paper, we discuss the effect of the ionic liquids (alkylimidazolium salts) with respect to their anion (bromide, chloride, tetrafluoroborate, and hexafluorophosphate) and the length of alkyl chain in the cation (allyl-, ethyl-, butyl-, hexyl-, and octyl-) on the vulcanization kinetics of rubber compounds. The influence of ionic liquids on the cross-link density, the mechanical properties of the vulcanizates, and their resistance to weather ageing were also studied. Alkylimidazolium salts seem to improve the dispersion of the coagent particles and to be active in the cross-linking of HNBR with peroxide. The type of ionic liquid considerably influences the activity of the coagent particles toward the HNBR. The application of ionic liquids increases the cross-link density of the vulcanizates and improves their resistance to weather aging. Magdalena Maciejewska and Marian Zaborski Copyright © 2013 Magdalena Maciejewska and Marian Zaborski. All rights reserved. Sun, 07 Apr 2013 10:23:36 +0000 http://www.hindawi.com/journals/composites/2013/140127/ Composite structures are increasingly used in the transport industry especially in the aeronautical sector thanks to their favorable strength-to-weight ratio with respect to metals. However, this is true if the final part is defects free and complies with quality requirements. A main weakness in composites is porosity, which is likely to be introduced during manufacturing processes and which may knock down the material characteristics affecting its performance in service. Porosity plays a key role in sandwich structures, which involve novel metal foams as core, since the foam performance strongly depends on size and distribution of pores. The determination of porosity is mostly attained by destructive methods, which supply only a general indication linked to the production part number. Conversely, composites may entail local significant variation of porosity, which may be discovered only with effective nondestructive techniques. The attention of the present work is focused on the possibility to use infrared thermography to get information about the amount and distribution of porosity. In particular, two techniques: flash thermography and lock-in thermography are used to comply with requirements of both monolithic composites and metal foams. Cinzia Toscano, Carosena Meola, and Giovanni Maria Carlomagno Copyright © 2013 Cinzia Toscano et al. All rights reserved.