Conventional Explosives Research Articles

Development of the Quality Assurance/Quality Control Procedures for a Neutron Interrogation System

In order to perform Quality Assurance/Quality Control (QA/QC) procedures for a system dedicated to the neutron interrogation of objects for the presence of threat materials one needs to perform measurements of reference materials (RM) i.e. simulants having the same (or similar) atomic ratios as real materials. It is well known that explosives, drugs, and various other benign materials, contain chemical elements such as hydrogen, oxygen, carbon and nitrogen in distinctly different quantities. For example, a high carbon-to-oxygen ratio (C/O) is characteristic of drugs. Explosives can be differentiated by measurement of both (C/O) and nitrogen-to-oxygen (N/O) ratios. The C/N ratio of the chemical warfare agents, coupled with the measurement of elements such as fluorine and phosphorus, clearly differentiate them from the conventional explosives. Here we present the RM preparation, calibration procedure and correlations attained between theoretical values and experimentally obtained results in laboratory conditions for C/O and N/C ratios of prepared hexogen (RDX), TNT, DLM2, TATP, cocaine, heroin, yperite, tetranitromethane, peroxide methylethylketone, nitromethane and ethyleneglycol dinitrate simulants. We have shown that analyses of the gamma ray spectra by using simple unfolding model developed for this purpose gave a nice agreement with the chemical formula of created simulants, thus the calibration quality was successfully tested.

E-Smoking Liquids as Precursors for Liquid Nitroesters

Currently, E-smoking cigarettes are widely used and occur within all classes of society. This work investigated the use of E-smoking liquids for the synthesis of Nitroglycerin (NG) and 1,2-Propylene Glycol Dinitrate (PGDN), both considered as nitroester liquid high explosives. Two kinds of E-smoking liquids (10 mL) were investigated: nicotine free and with nicotine (10 mg/mL). Quantitative analysis of the glycerin and propylene glycol (PG) present in the E-smoking liquids was carried out by gas chromatography-mass spectrometry (GCMS), with calculation of the accuracy and precision parameters. The percentage of glycerin was (10-13 wt.%) and percentage of propylene glycol was (40-70 wt.%) The synthesis of pure NG and pure PGDN were performed with laboratory grade glycerin and propylene glycol and compared to the samples obtained from the E-smoking liquid. Differential Scanning Calorimetry (DSC) was used for the determination of the activation energy and the heat of decomposition for each synthesized explosive, using the Ozawa and Kissinger models. The brisance index was assessed by the witness plate test and compared with some conventional explosives (TNT and C4). Finally, the influence of nicotine (less than 2 wt.%) on the synthetic process and the detonic properties of the explosive mixture was studied.

Toxicokinetic Model Development for the Insensitive Munitions Component 3-Nitro-1,2,4-Triazol-5-One.

3-Nitro-1,2,4-triazol-5-one (NTO) is a component of insensitive munitions that are potential replacements for conventional explosives. Toxicokinetic data can aid in the interpretation of toxicity studies and interspecies extrapolation, but only limited data on the toxicokinetics and metabolism of NTO are available. To supplement these limited data, further in vivo studies of NTO in rats were conducted and blood concentrations were measured, tissue distribution of NTO was estimated using an in silico method, and physiologically based pharmacokinetic models of the disposition of NTO in rats and macaques were developed and extrapolated to humans. The model predictions can be used to extrapolate from designated points of departure identified from rat toxicology studies to provide a scientific basis for estimates of acceptable human exposure levels for NTO.

Microheterogeneous Structure of Local Melted Zones in the Process of Explosive Welding

The dispersed structures formed in the process of explosive welding and solidification after melting were investigated in areas near the interface. It was shown that melting can be initiated by particles flying away as a result of granulating fragmentation. This is the fastest process during explosive welding, which is similar to fragmentation in conventional explosions with the formation of fragments but occurring in the presence of a barrier. The reaction between the particles and their environment may lead to local heating sufficient for melting. This is confirmed by the observation of numerous particles of the refractory phase within the local melted zones. In the absence of mutual solubility of the initial phases, the solidified local melted zones are to a certain extent analogous to colloidal solutions of immiscible liquids. Correlations between the typical temperatures were obtained that determine the conditions for the formation of various types of colloidal solutions.

A flag-based algorithm and associated neutron interrogation system for the detection of explosives in sea–land cargo containers

Abstract Recent efforts in the simulation of sea–land cargo containers in active neutron interrogation scenarios resulted in the identification of several flags indicating the presence of conventional explosives. These flags, defined by specific mathematical manipulations of the neutron and photon spectra, have been combined into a detection algorithm for screening cargo containers at international borders and seaports. The detection algorithm's steps include classifying the cargo type, identifying containers filled with explosives, triggering in the presence of concealed explosives, and minimizing the number of false positives due to cargo heterogeneity. The algorithm has been implemented in a system that includes both neutron and photon detectors. This system will take about 10 min to scan a container and cost approximately $1M to construct. Dose calculations resulted in estimates of less than 0.5 mSv for a person hidden in the container, and an operator annual dose of less than 0.9 mSv.

Bioaccumulation kinetics of the conventional energetics TNT and RDX relative to insensitive munitions constituents DNAN and NTO in Rana pipiens tadpoles.

The manufacturing of explosives and their loading, assembling, and packing into munitions for use in testing on training sites or battlefields has resulted in contamination of terrestrial and aquatic sites that may pose risk to populations of sensitive species. The bioaccumulative potential of the conventional explosives 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and of the insensitive munitions (i.e., less shock sensitive) compound 2,4-dinitroanisole (DNAN) were assessed using the Northern leopard frog, Rana pipiens. Trinitrotoluene entering the organism was readily biotransformed to aminodinitrotoluenes, whereas no transformation products were measured for RDX or DNAN. Uptake clearance rates were relatively slow and similar among compounds (1.32-2.19 L kg(-1) h(-1) ). Upon transfer to uncontaminated water, elimination rate was very fast, resulting in the prediction of fast time to approach steady state (5 h or less) and short elimination half-lives (1.2 h or less). A preliminary bioconcentration factor of 0.25 L kg(-1) was determined for the insensitive munitions compound 3-nitro-1,2,4-trizole-5-one (NTO) indicating negligible bioaccumulative potential. Because of the rapid elimination rate for explosives, tadpoles inhabiting contaminated areas are expected to experience harmful effects only if under constant exposure conditions given that body burdens can rapidly depurate preventing tissue concentrations from persisting at levels that may cause detrimental biological effects.

Experimental Comparison of Shock and Bubble Heave Energies from Underwater Explosion of Ideal HE and Explosive Composite Mixtures Highly Enriched with Aluminum

Experimental data on shock wave and bubble heave energies at underwater explosion of charges based on highly enriched with aluminium explosive mixtures are reported. Al/O ratios of the mixtures used are varied from 1.31 to 2.36. Al-rich charges up to 30g were exploded in basin of 2 m in diameter and 5 m in depth. As a result, Al-rich mixtures used are demonstrates overall specific energies of underwater explosion up to twice higher than conventional high explosives.

Overview of Accelerators with Potential Use in Homeland Security

Quite a broad range of accelerators have been applied to solving many of the challenging problems related to homeland security and defense. These accelerator systems range from relatively small, simple, and compact, to large and complex, based on the specific application requirements. They have been used or proposed as sources of primary and secondary probe beams for applications such as radiography and to induce specific reactions that are key signatures for detecting conventional explosives or fissile material. A brief overview and description of these accelerator systems, their specifications, and application will be presented. Some recent technology trends will also be discussed.

Material discrimination using scattering and stopping of cosmic ray muons and electrons: Differentiating heavier from lighter metals as well as low-atomic weight materials

Reported is a new method to apply cosmic-ray tomography in a manner that can detect and characterize not only dense assemblages of heavy nuclei (like Special Nuclear Materials, SNM) but also assemblages of medium- and light-atomic-mass materials (such as metal parts, conventional explosives, and organic materials). Characterization may enable discrimination between permitted contents in commerce and contraband (explosives, illegal drugs, and the like). Our Multi-Mode Passive Detection System (MMPDS) relies primarily on the muon component of cosmic rays to interrogate Volumes of Interest (VOI). Muons, highly energetic and massive, pass essentially un-scattered through materials of light atomic mass and are only weakly scattered by conventional metals used in industry. Substantial scattering and absorption only occur when muons encounter sufficient thicknesses of heavy elements characteristic of lead and SNM. Electrons are appreciably scattered by light elements and stopped by sufficient thicknesses of materials containing medium-atomic-mass elements (mostly metals). Data include simulations based upon GEANT and measurements in the HMT (Half Muon Tracker) detector in Poway, CA and a package scanner in both Poway and Socorro NM. A key aspect of the present work is development of a useful parameter, designated the “stopping power” of a sample. The low-density regime, comprising organic materials up to aluminum, is characterized using very little scattering but a strong variation in stopping power. The medium-to-high density regime shows a larger variation in scattering than in stopping power. The detection of emitted gamma rays is another useful signature of some materials.

An analytical approach for quantification of glazing hazard in buildings subject to external explosive blasts

This paper describes a conservative analytical approach for quantification of glazing hazard in terms of number of casualties among building occupiers from flying glass fragments produced by shattered windows due to external explosive blast. Three main stages are discussed in the proposed analytical approach: modelling nonlinear transient–dynamic response of monolithic windows subjected to conventional explosions, conservative estimation of glass fragment trajectories influenced by additional aerodynamic forces due to vented blast pressures and estimation of casualties. Four injury severity levels are considered, ranging from minor cuts and bruises to multiple serious injuries with significant blood loss. The total kinetic energy of fragments at impact on occupiers is estimated and used to predict the severity level of injuries, with calculation based on available injury data from archive events. Comparison studies presented in this paper highlight the lack of robustness of existing methods towards quantification of glazing hazard due to explosive blasts. The proposed analytical method will be of direct importance to both engineers and practitioners involved with planning glazing retrofits for existing buildings and identifying cost-effective combinations of protection measures for new buildings.

A review of conventional explosives detection using active neutron interrogation

Conventional explosives are relatively easy to obtain and may cause massive harm to people and property. There are several tools employed by law enforcement to detect explosives, but these can be subverted. Active neutron interrogation is a viable alternative to those techniques, and includes: fast neutron analysis, thermal neutron analysis, pulsed fast/thermal neutron analysis, neutron elastic scatter, and fast neutron radiography. These methods vary based on neutron energy and radiation detected. A thorough review of the principles behind, advantages, and disadvantages of the different types of active neutron interrogation is presented.

Research topics in explosives - a look at explosives behaviors

The behaviors of explosives under many conditions - e.g., sensitivity to inadvertent reactions, explosion, detonation - are controlled by the chemical and physical properties of the explosive materials. Several properties are considered for a range of improvised and conventional explosives. Here I compare these properties across a wide range of explosives to develop an understanding of explosive behaviors. For improvised explosives, which are generally heterogeneous mixtures of ingredients, a range of studies is identified as needed to more fully understand their behavior and properties. For conventional explosives, which are generally comprised of crystalline explosive molecules held together with a binder, I identify key material properties that determine overall sensitivity, including the extremely safe behavior of Insensitive High Explosives, and discuss an approach to predicting the sensitivity or insensitivity of an explosive.

The Los Alamos detonating pellet test (DPT): PBX 9501 evaluation tests

High explosive (HE) Velocity of Detonation (VOD) measurements are usually conducted using rate-stick-type tests. This method is highly accurate if carefully implemented, but is relatively costly and may require kilograms or more of HE depending on its sensitivity. We present a novel technique for inferring VOD using a single HE pellet, which for Conventional High Explosives (CHEs) can use 10 gm of HE or even less. This attribute makes the Detonating Pellet Test (DPT) ideal for the preliminary performance characterization of newly synthesized HE materials. On the other end of the size spectrum, the DPT can be scaled to very large dimensions so as to minimize the HE load necessary to characterize highly insensitive HEs such as ANFO. The DPT exploits the fact that the detonation emerging from the pellet face can be made highly spherical over some central region. Spherical detonation breakout on the Sample Pellet (SP) face is described by a simple analytic equation, which depends on the VOD and the Center Of Initiation (COI). The latter is determined by separate characterization of the detonator, with a wave refraction correction at the detonator/SP interface. The SP VOD is then determined by fitting the ideal breakout equation, with specified detonator COI, to detonation breakout data obtained via streak camera. We develop the DPT method and appraise it using sample PBX 9501 data in particular, while discussing its benefits and limitations in general.

Shock initiation thresholds for projectiles with curved surfaces

The impacts of flat-nosed rods into bare conventional high explosives tend to produce either detonations or very little discernable reaction. In contrast impacts from projectiles with curved striking surfaces, such as round-nosed rods, can produce a range of reactions, some very vigorous, as well as detonations. The current work attempts to explain this complex behaviour. The identification of a predictive threshold as corresponding to the boundary of sub-detonic reactions for low pressure impacts, rather than the boundary between no reaction and detonation, is discussed in the light of experimental results. The structure of the impact shock is explored and the existence of two sonic boundaries is explained. The linkage between the theoretical initiation threshold and one of these sonic boundaries is obtained and the implications of this threshold in terms of the proportion of the diameter of the projectile needed to cause initiation are discussed and the results illustrated using CREST, a hydrocode-based reactive-burn explosive model.

Acceleration of plates using non-conventional explosives heavily-loaded with inert materials

The detonation behavior of high explosives containing quantities of dense additives has been previously investigated with the observation that such systems depart dramatically from the approximately "gamma law" behavior typical of conventional explosives due to momentum transfer and thermalization between particles and detonation products. However, the influence of this non-ideal detonation behavior on the divergence speed of plates has been less thoroughly studied and existing literature suggests that the effect of dense additives cannot be explained solely through the straightforward application of the Gurney method with energy and density averaging of the explosive. In the current study, the acceleration history and terminal velocity of aluminum flyers launched by packed beds of granular material saturated by amine-sensitized nitromethane is reported. It was observed that terminal flyer velocity scales primarily with the ratio of flyer mass to mass of the explosive component; a fundamental feature of the Gurney method. Velocity decrement from the addition of particles was only 20%-30% compared to the resulting velocity if propelled by an equivalent quantity of neat explosive.

Air–snowpack exchange of bromine, ozone and mercury in the springtime Arctic simulated by the 1-D model PHANTAS – Part 1: In-snow bromine activation and its impact on ozone

Abstract. To provide a theoretical framework towards a better understanding of ozone depletion events (ODEs) and atmospheric mercury depletion events (AMDEs) in the polar boundary layer, we have developed a one-dimensional model that simulates multiphase chemistry and transport of trace constituents from porous snowpack and through the atmospheric boundary layer (ABL) as a unified system. This paper constitutes Part 1 of the study, describing a general configuration of the model and the results of simulations related to reactive bromine release from the snowpack and ODEs during the Arctic spring. A common set of aqueous-phase reactions describes chemistry both within the liquid-like layer (LLL) on the grain surface of the snowpack and within deliquesced "haze" aerosols mainly composed of sulfate in the atmosphere. Gas-phase reactions are also represented by the same mechanism in the atmosphere and in the snowpack interstitial air (SIA). Consequently, the model attains the capacity of simulating interactions between chemistry and mass transfer that become particularly intricate near the interface between the atmosphere and the snowpack. In the SIA, reactive uptake on LLL-coated snow grains and vertical mass transfer act simultaneously on gaseous HOBr, a fraction of which enters from the atmosphere while another fraction is formed via gas-phase chemistry in the SIA itself. A "bromine explosion", by which HOBr formed in the ambient air is deposited and then converted heterogeneously to Br2, is found to be a dominant process of reactive bromine formation in the top 1 mm layer of the snowpack. Deeper in the snowpack, HOBr formed within the SIA leads to an in-snow bromine explosion, but a significant fraction of Br2 is also produced via aqueous radical chemistry in the LLL on the surface of the snow grains. These top- and deeper-layer productions of Br2 both contribute to the release of Br2 to the atmosphere, but the deeper-layer production is found to be more important for the net outflux of reactive bromine. Although ozone is removed via bromine chemistry, it is also among the key species that control both the conventional and in-snow bromine explosions. On the other hand, aqueous-phase radical chemistry initiated by photolytic OH formation in the LLL is also a significant contributor to the in-snow source of Br2 and can operate without ozone, whereas the delivery of Br2 to the atmosphere becomes much smaller after ozone is depleted. Catalytic ozone loss via bromine radical chemistry occurs more rapidly in the SIA than in the ambient air, giving rise to apparent dry deposition velocities for ozone from the air to the snow on the order of 10−3 cm s−1 during daytime. Overall, however, the depletion of ozone in the system is caused predominantly by ozone loss in the ambient air. Increasing depth of the turbulent ABL under windy conditions will delay the buildup of reactive bromine and the resultant loss of ozone, while leading to the higher column amount of BrO in the atmosphere. During the Arctic spring, if moderately saline and acidic snowpack is as prevalent as assumed in our model runs on sea ice, the shallow, stable ABL under calm weather conditions may undergo persistent ODEs without substantial contributions from blowing/drifting snow and wind-pumping mechanisms, whereas the column densities of BrO in the ABL will likely remain too low in the course of such events to be detected unambiguously by satellite nadir measurements.

Innovative unconventional oil extraction technologies

New unconventional oil extraction technologies are needed because conventional technologies to extract gas and oil from oil shale or tar sands are both economically unfeasible and ecologically devastating. One technology proposed in this paper is built on long-standing proposals to explode a nuclear bomb in the heart of an oil shale deposit which in a flash causes the release of gas and oil from the oil shale. This rubble chimney will have a glassy bottom which seals the oil from sinking into the earth, thus preventing damage to the aquifer. The authors show that the equivalent of a significant atomic bomb can be achieved using conventional explosives or liquid oxygen and carbon. The computations further show that the amount of carbonous material lost in the explosion is a small price to pay for the safe in situ collection of the oil and gas. Computations show that this technology is both physically possible and economically feasible. A second approach is using the supercritical state — that exact point between liquid and gas — to extract the oil and gas from the oil shale and from the tar sands. In one configuration, the supercritical state is achieved by a sea-based configuration using the weight of water to provide sufficient pressure. A land-based alternative is a pressure well — a very deep well that similarly achieves sufficient pressure to produce the supercritical state. Supercritical carbon dioxide is frequently used in extraction using the supercritical state and the specific technology using carbon dioxide both in devices as well as in high pressure in situ. To contain the pollutants and maximize the output, a plasma tunneler heats the oil shale in situ and collects the oil and gas while the gases are contained in inflatable domes at the “worm hole” or the aperture that the earth penetration device was fed from. Other non-combustion proposals are advanced as well.

Experimental Study on Corner Effect of Emulsion Explosive in a Curved Charge based on Explosion-proof Application

Emulsion explosive is a common commercial explosive used in mining and demolition fields. As an energy output source, many accidents happened in the manufacturing of emulsion explosives. In order to understand the propagation process of detonation wave caused by emulsion explosive and ensure safety in manufacturing of emulsion explosives, this paper studied corner effect of emulsion explosives (EE) experimentally via detonation velocity measurement. In the series of experiments, obvious velocity deficits were observed during the whole propagation of detonation wave when emulsion explosives were charged in curved. Two important charge parameters, including curvature radius and cross section are of the charge, were investigated experimentally. Results showed that curvature radius played a more important role in the velocity deficit of detonation wave. After compared with that of conventional high explosives (CHE), results indicated that the corner effect acted on emulsion explosives was more obvious than that of conventional high explosives.

English

BACKGROUND: Firearms and explosives constitute convenient means of destroying human life from considerable distance. OBJECTIVE: Study of wounds in victims of homicide by fireams and explosives. METHODS: The present study comprised of one hundred cases of homicidal firearms and explosives injuries drawn from the medicolegal autopsies held in the mortuary of the department of Forensic Medicine. RESULTS: There was presence of firearms erntry wounds in all (100%) victims and presense of exitwounds only in 61.36 % Victims. In majority (61.36)% of victims firearm exit wounds were present.One exit wound was present in 16(18.18%) Victims. Two exit wounds in 17(19.31%) victims, three exit wound in 9 (10.22%) victims and more then three firearm exit wounds in 12(13.63%) victims. It was revealed that in maximum (46.59%) brain and meninges were injured, followed by pleura and lungs (20.45%) pericardium and heart in 18.18 per cent. These were followed by ribs (15.90%), liver in 13.63 per cent. Aorta (9.9%), stomach (6.80), small intestine (5.68%) and large intestine in 4.54 per cent. All (100.00%) homicidal victims of explosive injuries showed burning, abrasions and contusions. Lacerations were seen in 91.66 percent victims. However, blackening was seen in 83.33 per cent and tattooing in 75 per cent victims. It was found in three fourth (75%) of victims of fatal explosive injuries there were no other associated injuries by any other weapon than explosive. In one victim (8.33%) associated injuries by firearm was present and that caused his death. However, in two victims (16.66%) associated injuries (by fire arm and blunt weapon) were present but they were not fatal. In all 12 (100%) victims recived injuries on multiple body parts amongst whish injuries on chest were in 9 (91.66%), neck (75%), head (66.66%), abdomen (66.66%). Injuries on upper extremity was seen in 50 per cent and on the lower extremity in33.33 per cent. Findings on frequency of involvement of various internal organs and structures in the victim of homicides by explosives showed that in well over three fourth of victims(83.33%) pleura and lungs were involved followed by pericardium and heart(75%), ribs(75%), aorta(66.66%),(58.23%).In the equal number of victims i.e.(58.33%) vessels inneck and pharynx were involved. In 50 % if victims oesphagus,theoric vertebrae and major abdominal blood vessels were involved.In 41.66 % victims of explosive injuries,cervical vertebrae , thoracic cord,Pancreas,stomach,lumber vertebrae,spleen and bones of upper extremities were involved.In one third of victims (33.33%) small intestine, large intestine,uraniry bladder,joints of upper extremity, muscles and vessels of lower extremity were involved.In only one fourth (25%) of victim menstery, bones and joints of lower extremity were injured. CONCLUSION: In view of the complexities created by the introduction of newer and newer improvised and conventional firearms and explosives in most of the areas, the establishment of various facts in a cases of firearm death, such as the type of weapon used, the range of firing, the direction of fire, the number of shots fired, wound of entry and exit and the damage to vital parts and the like, have become fraught with serious and many fold difficulties and complexities for the Forensic Pathologists and ballistic experts.

Dynamic Buckling Behaviors of Steel Cylindrical Shell Subjected to Conventional Explosion Impact Loading

Experimental and numerical simulation researches were presented on dynamic buckling behaviors of cylindrical shell subjected to explosion loading.An account is given of some principal observations made from a series of experiments in which steel cylindrical shells were subjected to central impact by 200g cylindrical TNT dynamite with different distances.By means of an finite element computer code LS-DYNA,the nonlinear dynamic response process of the cylindrical shells subjected to explosion loading were numerically simulated with Lagrangian-Eulerian coupling method. The numerical simulation results were in good agreement with experimental data. The results provide a reference for the design of explosion-resisting structures.