Nic Daeid N.,University of Dundee |
Yu H.A.,University of Dundee |
Yu H.A.,Curtin University Australia |
Beardah M.S.,UK Defence Evaluation and Research Agency
Science and Justice | Year: 2017
Explosives residues are often collected from explosion scenes, and from surfaces suspected of being in contact with explosives, by swabbing with solvent-wetted cotton swabs. It is vital that any explosives traces present on the swabs are successfully extracted and detected when received in a laboratory. However, a 2007 proficiency test initiated by the European Network of Forensic Science Institutes (ENFSI) Expert Working Group on Explosives involving TNT-spiked cotton swabs highlighted that explosives may not always be detected from such samples. This paper outlines work performed to determine potential reasons for this finding. Cotton swabs were spiked using a solution of TNT and stored in nylon bags and glass vials for periods of 1, 2 and 4 weeks. Simulated swab extracts were also prepared and investigated. The samples were stored in a freezer, or at room temperature either in the dark or exposed to daylight. Overall, the cotton swabs stored at room temperature and exposed to daylight showed a very rapid loss of TNT over time, whereas cotton swabs stored in the freezer, and all simulated swab extracts, gave high recoveries over time. These results will be of benefit for practicing forensic explosives laboratories and for persons undertaking cold-case reviews involving explosive-based samples. © 2016 The Chartered Society of Forensic Sciences
Millar D.I.A.,University of Edinburgh |
Oswald I.D.H.,Strathclyde Institute of Pharmacy and Biomedical science |
Barry C.,Rutherford Appleton Laboratory |
Francis D.J.,Rutherford Appleton Laboratory |
And 3 more authors.
Chemical Communications | Year: 2010
The high-pressure, high-temperature ε-form of the widely used explosive RDX has been structurally characterised using a combination of diffraction techniques, and a sample of this form has been successfully recovered to ambient pressure. © 2010 The Royal Society of Chemistry.
Farhan Shafique M.,University of Leeds |
Laister A.,University of Leeds |
Clark M.,UK Defence Evaluation and Research Agency |
Miles R.E.,University of Leeds |
Robertson I.D.,University of Leeds
Journal of the European Ceramic Society | Year: 2011
This paper describes the application of laser micromachining techniques for the fabrication of microfluidic channels in low temperature co-fired ceramic, LTCC, technology. It is shown that embedded cavities can be successfully realised by employing a recently proposed progressive lamination process with no additional fugitive material. Various microfluidic structures have been fabricated and X-ray imaging has been used to assess the quality of the embedded channels after firing. The problem of achieving accurate alignment between LTCC layers is addressed such that deeper channels, spanning more than one layer, can be fabricated using a pre-lamination technique. A number of possible applications for the presented microfluidic structures are discussed and an H-filter particle separator in LTCC is demonstrated. © 2011 Elsevier Ltd.
Millar D.I.A.,University of Edinburgh |
Maynard-Casely H.E.,University of Edinburgh |
Allan D.R.,Diamond Light Source |
Cumming A.S.,UK Defence Evaluation and Research Agency |
And 6 more authors.
CrystEngComm | Year: 2012
Co-crystallisation is proposed as an effective method to adapt the physico-chemical properties of energetic materials, thus presenting the opportunity to fine-tune performance characteristics at the molecular level. This is illustrated by the characterisation of four co-crystals of the high explosive CL-20. © 2012 The Royal Society of Chemistry.
Ho M.Y.,University of Cambridge |
D'Souza N.,UK Defence Evaluation and Research Agency |
Migliorato P.,University of Cambridge |
Migliorato P.,Kyung Hee University
Analytical Chemistry | Year: 2012
Electrochemical impedance spectroscopy (EIS) is used to detect 2,4,6-trinitrotoluene (TNT) in a novel sandwiched structure which relies on the specific interactions between (i) primary amine with TNT and (ii) TNT and anti-TNT aptamer. With pure targets, the assay has a sensitivity of 10 -14 M, a dynamic range of 10 -14-10 -3 M, and employs a small sample volume (25 μL). The method's sensitivity is comparable to state of the art optical methods with the added advantages of electrochemical detection, which can be easily miniaturized and implemented into a hand-held device. © 2012 American Chemical Society.
Black J.V.,UK Defence Evaluation and Research Agency |
Reed C.M.,UK Defence Evaluation and Research Agency
European Control Conference, ECC 1999 - Conference Proceedings | Year: 2015
When local tracks are fused to produce a global track, allowing for dependence, the approximations necessary for economic track representation can result in an unlocalised, posterior track distribution and tracker failure. This paper describes two approaches to robust track fusion. Each produces a modified version of the usual formula which undoes the adverse effects of the approximations. The general principles are applied here to the case of Gaussian mixture modelling of tracks. © 1999 EUCA.
Novac B.M.,Loughborough University |
Smith I.R.,Loughborough University |
Senior P.,Loughborough University |
Parker M.,Loughborough University |
Louverdis G.,UK Defence Evaluation and Research Agency
Review of Scientific Instruments | Year: 2010
High-power applications sometimes require a transportable, simple, and robust gigawatt pulsed power generator, and an analysis of various possible approaches shows that one based on a twin exploding wire array is extremely advantageous. A generator based on this technology and used with a high-energy capacitor bank has recently been developed at Loughborough University. An H-configuration circuit is used, with one pair of diagonally opposite arms each comprising a high-voltage ballast inductor and the other pair exploding wire arrays capable of generating voltages up to 300 kV. The two center points of the H configuration provide the output to the load, which is coupled through a high-voltage self-breakdown spark gap, with the entire autonomous source being housed in a metallic container. Experimentally, a load resistance of a few tens of Ohms is provided with an impulse of more than 300 kV, having a rise time of about 140 ns and a peak power of over 1.7 GW. Details of the experimental arrangement and typical results are presented and diagnostic measurements of the current and voltage output are shown to compare well with theoretical predictions based on detailed numerical modeling. Finally, the next stage toward developing a more powerful and energetic transportable source is outlined. © 2010 American Institute of Physics.
Giannakis I.,University of Edinburgh |
Giannopoulos A.,University of Edinburgh |
Davidson N.,UK Defence Evaluation and Research Agency
2012 14th International Conference on Ground Penetrating Radar, GPR 2012 | Year: 2012
A new technique based on a hybrid linear-nonlinear optimization is suggested in order to simulate the Cole-Cole dispersion mechanism using a number of Debye functions. A novel method to implement this multi-Debye medium, based on a recursive integration algorithm is also presented. These new techniques are used to simulate the experimental Cole-Cole parameters for dry and moist sand . ©2012 IEEE.
Haig N.D.,UK Defence Evaluation and Research Agency
Perception | Year: 2013
Human beings possess a remarkable ability to recognise familiar faces quickly and without apparent effort. I spite of this facility, the mechanisms of visual recognition remain tantalisingly obscure. A experiment is reported in which image processing equipment was used to displace slightly the features of a set of original facial images to form groups of modifed images. Observers were then required to indicate whether they were being shown the "original" or a "modifed" face, when shown one face at a time on a TV monitor screen. Memory reinforcement was provided by displaying the original face at another screen position, between presentations. The data show, inter alia, the very high signifcance of the vertical positioning of the mouth, followed by eyes, and then the nose, as well as high sensitivity to close-set eyes, coupled with marked insensitivity to wide-set eyes. Implications of the results for the use of recognition aids such as Identikit and Photoft are briefy discussed. © 1984 a Pion publication printed in Great Britain.
Crowson A.,UK Defence Evaluation and Research Agency |
Cawthorne R.,UK Defence Evaluation and Research Agency
Science and Justice | Year: 2012
The Forensic Explosives Laboratory (FEL) operates within the Defence Science and Technology Laboratory (DSTL) which is part of the UK Government Ministry of Defence (MOD). The FEL provides support and advice to the Home Office and UK police forces on matters relating to the criminal misuse of explosives. During 1989 the FEL established a weekly quality assurance testing regime in its explosives trace analysis laboratory. The purpose of the regime is to prevent the accumulation of explosives traces within the laboratory at levels that could, if other precautions failed, result in the contamination of samples and controls. Designated areas within the laboratory are swabbed using cotton wool swabs moistened with ethanol:water mixture, in equal amounts. The swabs are then extracted, cleaned up and analysed using Gas Chromatography with Thermal Energy Analyser detectors or Liquid Chromatography with triple quadrupole Mass Spectrometry. This paper follows on from two previous published papers which described the regime and summarised results from approximately 14. years of tests. This paper presents results from the subsequent 7. years setting them within the context of previous results. It also discusses further improvements made to the systems and procedures and the inclusion of quality assurance sampling for the peroxide explosives TATP and HMTD. Monitoring samples taken from surfaces within the trace laboratories and trace vehicle examination bay have, with few exceptions, revealed only low levels of contamination, predominantly of RDX. Analysis of the control swabs, processed alongside the monitoring swabs, has demonstrated that in this environment the risk of forensic sample contamination, assuming all the relevant anti-contamination procedures have been followed, is so small that it is considered to be negligible. The monitoring regime has also been valuable in assessing the process of continuous improvement, allowing sources of contamination transfer into the trace areas to be identified and eliminated. © 2012.