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].

Explosives: The Threats and the Materials

Abstract: Publisher Summary This chapter describes the fundamentals of explosive technology and the properties of some common explosives. The detection-related aspects and their availability, performance, and any feature that might lead a terrorist to choose one over another are also discussed in this chapter. Chemical explosives, with proper initiation, undergo violent decomposition to produce heat, gas, and rapid expansion of matter and its practical effect depends on the speed at which the decomposition takes place as well as on the amount of gas and heat released. A chemical reaction which proceeds through the material at a rate less than or equal to the speed of sound in the unreacted material is known as a deflagration. A chemical reaction that proceeds through the material at a rate greater than the speed of sound in the unreacted material is known as a detonation. Explosives are classed as primary or secondary, and typically a small quantity of a primary explosive is used in a detonator, whereas larger quantities of secondary explosives are used in the booster and the main charge of a device. Plastic explosives are widely used in terrorist bombs and they contain one or more explosives, molded in an inert, flexible binder. As powders do not readily hold a shape and TNT is the only common melt-castable explosive, most of the explosive powders are plasticized to make a moldable material. To date, the terrorists have used FO (the commercial fuel), icing sugar (little associated odor), or aluminum (added heat release) and when these combustibles are added to AN, a more powerful material is obtained.

Terrestrial laser scanning for assessing the risk of slope instability along transport corridors

Abstract: Transport networks play a crucial part in the global economy, with roads and railways being of particular importance at regional and national scales. However, roads and railways are founded on earthworks such as embankments, which can be susceptible to slope failure. Slope instability is a costly problem, which can lead to travel disruption, and injury or loss of life. Earthwork stability assessment is therefore a critical activity for management bodies. However, current approaches are largely limited to hazardous onfoot site inspections. Although high resolution geospatial datasets are becoming increasingly available, there is currently a mismatch between the availability of these datasets, and the ability to use this data in support of decision making. This paper presents one aspect of an integrated methodology for risk assessment in transport corridor environments. The potential of terrestrial laser scanning (TLS) for assessment of slope deformation and failure is examined through application to two test sites in the north of England. The first site is a full-scale test embankment, while the second is a modern highway embankment. Results have shown that for both sites, multi-temporal TLS surveys facilitate the detection of minor changes, such as soil creep and surface runoff. However, vegetation was found to be a complicating factor, contributing to registration errors between individual scans. This was resolved through the use of a least squares surface matching algorithm, which ultimately facilitated detection of change at the centimetric level. These results confirm the potential of TLS for embankment stability assessment, while highlighting some of the practical limitations. * Corresponding author.

Experimental Respiratory Infection of Marmosets (Callithrix jacchus) With Ebola Virus Kikwit

Abstract: Ebola virus (EBOV) causes a highly infectious and lethal hemorrhagic fever in primates with high fatality rates during outbreaks and EBOV may be exploited as a potential biothreat pathogen. There is therefore a need to develop and license appropriate medical countermeasures against this virus. To determine whether the common marmoset (Callithrix jacchus) would be an appropriate model to assess vaccines or therapies against EBOV disease (EVD), initial susceptibility, lethality and pathogenesis studies were performed. Low doses of EBOV-Kikwit, between 4 and 27 times the 50% tissue culture infectious dose, were sufficient to cause a lethal, reproducible infection. Animals became febrile between days 5 and 6, maintaining a high fever before succumbing to EVD between 6 and 8 days after challenge. Typical signs of EVD were observed. Pathogenesis studies revealed that virus was isolated from the lungs of animals beginning on day 3 after challenge and from the liver, spleen and blood beginning on day 5. The most striking features were observed in animals that succumbed to infection, including high viral titers in all organs, increased levels of liver function enzymes and blood clotting times, decreased levels of platelets, multifocal moderate to severe hepatitis, and perivascular edema.