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Kings Hill, United Kingdom

Yu H.A.,University of Dundee | Yu H.A.,Curtin University Australia | Lewis S.W.,Curtin University Australia | Beardah M.S.,UK Defence Evaluation and Research Agency | NicDaeid N.,University of Dundee
Talanta | Year: 2016

It can be very challenging to recover explosives traces from porous surfaces, such as clothing and car seats, compared to non-porous surfaces. The contact heater has been developed as a novel instrument designed to recover explosives traces from porous surfaces. Samples are taken by heating and drawing air across a surface, with the air flowing through a sampling cartridge containing adsorbent polymer beads, which act to trap any recovered explosive material. Any collected explosive can then be eluted from this cartridge using a solvent, prior to analysis. This paper outlines work performed to evaluate the usefulness of the contact heater with regards to the recovery of explosives traces from porous materials. Ethylene glycol dinitrate (EGDN) and triacetone triperoxide (TATP) were chosen as two representative explosives for this study. Quantification was performed using GC-MS for EGDN and LC-MS/MS for TATP. Different sampling temperatures, sampling times and elution solvents were investigated. Recovery was trialled from leather, carpet and denim. Recoveries of up to 71% were obtained following optimisation. It was also possible to recover TATP from fabrics exposed to TATP vapour in a vapour-laden jar up to two hours after exposure. The contact heater therefore appears to be a very useful tool for the recovery of explosives traces from porous materials. © 2015 Elsevier B.V. Source

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. Source

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. Source

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 [20]. ©2012 IEEE. Source

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. Source

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