Defence Science and Technology Laboratory

About: Defence Science and Technology Laboratory is a government organization based out in Salisbury, United Kingdom. It is known for research contribution in the topics: Burkholderia pseudomallei & Francisella tularensis. The organization has 926 authors who have published 1242 publications receiving 30091 citations. The organization is also known as: Dstl & [dstl].

Psychology, risk, health and deployed military operations.

Abstract: This article will focus on a study by the UK Defence Science and Technology Laboratory (Dstl) which investigated the risk propensity and health behaviours of UK army personnel deployed to Iraq in 2007 as part of Op TELIC. The study addressed the concept of impulsive sensation seeking and how this interacted with health behaviours associated with alcohol, smoking, driving and sex at predeployment, during deployment and postdeployment, as well as perceptions of risk and psychological well-being. There is also a description of other deployment-related risk and health research and analysis undertaken by Dstl as part of a wider discussion on the nature of both risk and health on deployed operations.

Indication of slowly moving ground targets in non-gaussian clutter using multi-channel synthetic aperture radar

Abstract: The problem of how best to maximise the ratio of mean target intensity to mean background intensity for slowly moving targets in sets of multi-channel synthetic aperture radar images is discussed for highly non-Gaussian background clutter. The problem is formulated as a direct maximisation of target-to-clutter ratio thus giving a true maximisation of that ratio. Complex-valued weights derived using generalised eigensystem theory are used to maximise the ratio of quadratic forms representing the mean intensity of the target and background derived from their coherence matrices. For two to four channels it is shown that when the target is highly coherent an optimum steering vector is a discrete Fourier transform. For more than two channels it is shown that the optimal solution is only valid within a subspace of the whole parameter space defined by the correlation parameters of the background clutter. Images from a publically released ground moving target indicator dataset are filtered using the results for three channels. The method outperform a standard space-time adaptive processing algorithm in suppressing the stationary background urban clutter image intensity relative to the image intensity because of a known slowly moving ground vehicle. Moreover, the steering vector is much simpler to implement.

Nonlinear Raman spectroscopy of liquid crystals: orientational alignment and switching behaviour in a ferroelectric liquid crystal mixture

Abstract: Picosecond inverse Raman spectroscopy has been employed to probe the alignment behaviour and switching characteristics of a 6 μm thick ferroelectric liquid crystal based on a host mixture of fluorinated phenyl biphenyl-carboxylates and a chiral dopant. Optical bistability is observed in the Raman signal on application of dc electric fields of opposite polarity. For particular polarities of the applied field, the Raman signals display a cos4 θ dependence on the angle of rotation around the beam direction. Reorientational rate constants of 300 μs and 590 μs are observed for the aromatic core at the high-voltage limit for the rise and decay of the 1600 cm−1 Raman signal on application of a switching ac electric field.