No abstract

No abstract

Abstract." The flow behaviour of pure and commercial molten TNT when subjected to very high rates of shear in a rotational viscometer over the temperature range 82.0 to 95.4 °C is presented. All data obtained suggest that the behaviour of molten TNT is Newtonian, contrary to the conclusions of some published work, and the temperature dependence of the viscosity of pure TNT is adequately described by an Arrhenius-type relationship of the form ~/= A e B/T where A = 0.000541, B = 3570 and T is the Kelvin temperature. A similar relationship is obtained for commercial TNT. Under some instrumental conditions discontinuities are seen in the shear stress-shear rate flow curves. An analysis of these discontinuities shows them to be caused by the transition from laminar to turbulent flow. Possible implications for processibility and initiation of explosives are discussed.

The viscosity of pure molten TNT has been investigated over the temperature range 82.0°-95.4 °C. The temperature dependence of viscosity was found to be best represented by a relation of the type q = A e wT where A = 0.000541, B -= 3570, r/is the viscosity in mPa s and T is the temperature in Kelvin. Earlier work, which suggests an inverse temperature dependence of the flow activation energy, is shown to include an error in the published equation for the temperature dependence of the viscosity of molten TNT.

In this paper we present preliminary results of ballistic testing and thermal measurement of a functional structure consisting of phase change material (PCM) and soft armour layers made of Kevlar. The purpose of this study is to explore the feasibility of combining thermal management with ballistic protection in a single system such that the thermal stress of dismounted combat personnel may be mitigated to an extent while wearing their body armour in hot and humid environments. Under such conditions the breathability of smart textiles will offer little to no benefit. In our study each Kevlar sheet is coated with PCM from Microtek Laboratories Inc. and bonded with normal PVA wood glue. Twenty coated layers were prepared for ballistic testing and compared with twenty pure Kevlar layers as reference. The cooling power of the soft armour insert (SAI) with PCM was measured on a heated sweating manikin. The proof of concept results show that the SAI with PCM only produced a mild cooling effect, which may lower skin temperature and provide a mild cooling sensation for a body region that would otherwise allow limited heat loss, due to the impermeability of the SAI.