Experiments and Modeling for Biocidal Effects of Explosives

Abstract

] 1IntroductionBacterial spores such as Bacillus anthracis (anthrax) are potentially highly dangerous to human health, see for example Whitney et al. [1].E nergetic materials offer ap otential for rapid neutralization of such threats in operational environments since detonation and combustion can produce hot and in some cases corrosiveg ases, whichh ave ab iocidal effect.R ecent work by McCartt,G ates, and co-workers [2-4] and references cited therein has studied spore resistance to gasdynamic heating using aerosolized spores suspended in as hock tube and finds that significant neutralization occurs at temperatures above 650 K. Significant endospore damage is observed at temperatures above 750 K. Gottiparthi et al. [5] have built on the above data in numerical studies of neutralization of spores in post-detonation (using nitromethane as the explosive) free-field flows. There they considerasimple neutralization model where spores are neutralized if their temperature exceeds ac ritical temperature, which they take to be 670 K. Schulz et al. [6] have carried out systematic sensitivity studies basedo nt his modeling techniquea nd conclude that the residence time in the hot gases is ad ominant parameter.In our workw ec onsider detonation in an enclosed environment, where residence times are naturally much longer than in free field. The energetic material studied is Valimet H-2 aluminum powder,s hock dispersed by detonation of ac entral high explosive( HE) core. The experimental apparatus consists of two coupled closed chambers. The first chamber contains the energeticm aterial and is initially filled with Bacillust huringiensis Al Hakam (BtAH) sporesi n an aerosol. On detonation, the gasesa re free to vent into the second (exhaust) chamber, simulating venting from as tructure damaged by ab io-agent defeat strike. After the event, spores are captured from both chambers for postprocessing to determine the fraction remainingv iable. The primary diagnosticsa re the conditions in the detonation chamber and the resultingp ercentage of surviving spores.We also report the results of ar ange of numerical modeling studiesc arried out to aid the interpretation of these ex- Abstract:T his paper reports an experimental and modelling study of the biocidal effect of an energeticm ixture which is detonated in ac losed chamber containing an initial spore distribution. The resulting spore neutralization efficiency is recorded as af unctiono fm easuredd etonation and combustion performance. We also report the results of ar ange of numerical modelling studies carried out to aid the interpretation of these experiments and to guide future developments. We find that the current energetic mixture (aluminum powder whichi ss hock dispersed by detonation of ac entralh igh explosivec ore)g ives variable combustion efficiency.T he Al powder ignites on impact with the walls. In the modelling we matcht he recorded quasi-static pressures in each experiment and compare predicteds pore neutralization with measured values. Using ac riticals pore tempe...

Aluminum-based materials for inactivation of aerosolized spores of Bacillus anthracis surrogates

“…In parallel, combustion dynamics of the prepared reactive material powders have been characterized, focusing on the ignition temperatures and burn times of composite, halogen containing particles (Adhikari et al 2016;Aly et al 2014;Zhang et al 2010a;Abraham et al 2013;Wang et al 2016a). Reliable data on both the combustion dynamics and biocidal properties of new reactive materials are critical in supporting research on development of new explosive formulations and on modeling their energetic performance and effectiveness against biological agents (Henderson et al 2015). This work extends the previous efforts dealing with the development of aluminum-based fuel additives generating biocidal combustion products (Abraham et al 2013;Grinshpun et al 2012;Zhang et al 2012aZhang et al , 2010aAbraham et al 2014).…”

Creation of energetic biothermite inks using ferritin liquid protein

“…4 ). This provides an effective method to transfer and write energetic materials onto any contaminated surface and neutralize any biological/chemical agents by combustion of the ink 50 . Alternatively, we can likely prevent melting and phase change of our 3D energetic structures by tuning the physical properties of the ferritin protein ionic liquid.…”

Mg‐based reactive materials with high iodine concentration and biocidal characteristics of aerosolized Mg‐based biocidal materials

“…Few studies were carried out qualitatively measuring the inactivation rate of bio-agent defeats. Three methods were mainly used to test the inactivation properties: (1) Adding bacteria into culture dishes with the reaction products [11,23,24]; (2) Exposing bacteria aerosol to the flame with combustion products of antibiocidal agents in an open environment [22,25,26]; (3) Placing bacteria in a closed container and collecting the products after constant volume explosion (CVE) of antibiocidal agents [27,28]. Since the bio-agent defeats were expected to be exploded in factory and storage of bioweapons, they should directly interact with airborne spores as aerosols in a close environment after deployment.…”