Improvised Explosive Research Articles

Continuous Monitoring of TATP Using Ultrasensitive, Low-Power Sensors

There is a growing need for a continuous monitoring system that can detect explosives such as triacetone triperoxide (TATP) in the vapor phase at trace levels. TATP is an energetic material commonly used by terrorists in improvised explosive devices both as the initiator and the energetic material itself. TATP is still going largely undetected in many densely populated venues such as train stations and airports. No electronic trace detection system currently exists that is capable of continuously monitoring TATP, or its precursors, in the vapor phase. Recently, we developed a thermodynamic sensor that can detect TATP and other nitrogen-based explosives in the vapor phase at the ppb level. These ultrathin sensors showed unparalleled sensitivity and could even be operated at low enough powers to enable them to be deployed on drones. The sensor relies on specific oxidation-reduction reactions between the energetic molecules and metal oxide catalysts. Here, catalyst coated microheaters measure the heat effects associated with redox reactions occurring on the surface of the metal oxide catalyst. Enhanced sensitivity and selectivity were achieved through implementation of ultrathin ($8~\mu \text{m}$ thick) yttria-stabilized-zirconia (YSZ) as the substrate for the sensor platform. This reduction in the thermal mass combined with the catalytic amplification associated with Pd microheaters and optimized catalyst porosity enabled us to detect TATP in the vapor phase at unprecedented levels.

The illegal synthesis of picric acid in the context of applicable legal regulations

Homemade explosives (HME) are increasingly used in terrorist attacks. These materials can be defined as physical mixtures of commonly available raw materials or those obtained by synthesis e.g. picric acid. For most compounds there are at least several synthesis routes which allow a suitable route to be matched for the available materials. The aim of the task was to investigate the possibility of producing picric acid using raw materials and equipment available to the average user. The obtained product was tested for safety, i.e. sensitivity to friction and impact was determined.

Cardiac Cycles Appear Linked to Perceptions of Threat and Fear

Cardiac Cycles Appear Linked to Perceptions of Threat and Fear

Combat injuries sustained by troops on counter terrorism and counter-insurgency operations in North east Nigeria: Implications for intervention.

BackgroundUnderstanding the epidemiology of battlefield casualties is required for plans and coordinated efforts towards improved combat trauma care (CTC) performance and outcome. The engagement of the Armed Forces of Nigeria (AFN) in containing Boko Haram Terrorism (BHT) and insurgency in Northeast Nigeria has increased the risk of combat injuries to the troops. This study determined the characteristics of combat injuries sustained by soldiers on counter terrorism and counter-insurgency operations to contain BHT.MethodsA retrospective cross-sectional study of combat casualties managed in 7 Division (Field) Hospital, [an equivalent of UN Level 2 facility] Maiduguri, Northeast Nigeria between November 2013 and October 2014. Using data obtained from a designed Operational Casualty Card that contains their sociodemographic characteristics, categorization (as Combat Arm, Combat Support Service, Civ-JTF), nature, mechanism and sites of injury as well as inpatients records. The data were collated and analysed using SPSS version 20.ResultsA total of 209 casualties were treated. The age of the casualties ranged from 18 to 57 years with a mean of 30.6 ± 7.7 years and males constituting 99%. Over two-third (71.3%) casualties had gunshot injuries while 14.3% and 8.1% sustained improvised explosive device (IED) and fragments injuries respectively. Over three-quarter (77.5%) sustained injuries on the upper and lower extremities while 17 (7.7%) and 12 (5.7%) had injuries on thorax/abdomen and head/neck respectively. Nineteen (9.1%) casualties resulted from friendly forces/colleagues.ConclusionThe study revealed that gunshot and IED/blasts on the extremities were the most frequent mechanism and pattern of injuries sustained with less than a tenth of the casualties resulting from friendly forces. Training health personnel on CTC, deployment of combat lifesavers to improve pre-hospital CTC, employment of skilled Orthopaedic Surgeon and other relevant surgical subspecialties and timely air evacuation of critical cases from the Field Hospital to the Base Hospital are recommended.

Evaluating the effect of shape on energy absorbing response of structures used in armored vehicles floors

Improvised explosive devices (IEDs) are a major threat to the lives and wellbeing of soldiers transported in armored vehicles. The blast of an IED under vehicle body can cause severe injuries especially to the lower extremities of vehicle occupants. Blast-mitigating structures are developed to absorb as much energy as possible to protect occupants from the effect of blast. These structures are placed on vehicle floor to soften the impact on occupants’ lower extremities thus minimizing injuries. Shape plays an important role in determining the amount of energy absorbed in these structures. This paper presents a finite element study where nonlinear finite element (FE) models were used to simulate the motion of vehicle floor due to the blast of an IED. A benchmark structure was developed to mimic Skydex that is a trademark structure. Different shapes were then used and compared with Skydex. The study shows the potential of optimizing shape to maximize the performance of blast-mitigating structures.

INVESTIGATION ON THE EXPLOSIVE CHARACTERISTICS AND DAMAGE MODE OF CYLINDRICAL IMPROVISED EXPLOSIVE DEVICES

To study the explosive characteristics of improvised explosive devices (IEDs), the damage mode of cylindrical IEDs and the formation mechanism of natural fragments under blast loading are investigated by using the ANSYS/AUTODYN 3D finite element code with Mott’s stochastic failure model, as well as experiments of the hydraulic burst test and explosion test. The influence of the explosive charge amount and its position is also discussed. The main damage mode of the pressure container is the shearing damage, which is obviously affected by the explosive charge amount, charge position, and its power. The ability of the instantaneous function (pressurization rate) of the self-made explosive is far smaller than that of the standard explosive. Under the action of the self-made explosive, the closer to the detonation point, the smaller the size of the fragments formed.

Pars plana vitrectomy timing in deadly weapon-related open-globe injuries.

The objective of this study is to evaluate the effect of vitrectomy timing on anatomical and functional outcomes in cases with open-globe injuries caused by improvised explosive devices (IEDs). A retrospective review of ocular injuries caused by IEDs was undertaken. The eyes were classified into four groups based on the timing of vitrectomy: early (Group-1; 2-4 days), delayed (Group-2; 5-7 days), late (Group-3; 8-14 days) and very late (Group-4; >14 days). The medical records of 351 patients were reviewed, and 212 patients were excluded. A total of 189 eyes of the remaining 139 patients were analysed. Visual improvements were statistically significant compared to the baseline values in all groups (p < 0.001). The early group showed better functional and structural outcomes when compared to the other groups. There was also no proliferative vitreoretinopathy (PVR) in the early group, while PVR was at the highest rate (25%) in the very late group and constituted the most significant reason for recurrent retinal detachment. Both functional and anatomical outcomes were better in the early group. Delayed surgery may be indicated for some cases, but 1-week interval seems to be an optimal time-frame in open globe injuries due to IEDs.

Characterization and differentiation of aluminum powders used in improvised explosive devices - Part 1: Proof of concept of the utility of particle micromorphometry.

Aluminum (Al) powders are commonly used in improvised explosive devices as metallic fuels, a component of explosive mixtures. These powders can be obtained readily from industrial-scale and consumer products, and produced using unsophisticated "kitchen chemistry" techniques. This research demonstrates the potential of automated particle micromorphometry for comparisons between known source and questioned Al powders recovered from IEDs, as well as for insight into the method of Al powder manufacture. Al powder samples were obtained from legitimate manufacturers, and 56 samples were produced "in-house" from Al-containing spray paints and ball-milled Al foils. Transmitted light microscope images of Al powder particles were acquired using an automated stage with automated z-focus; 17 size and shape parameters were measured for all particles. Approximately 37,000-2,500,000 particles/sample were analyzed using an open-source statistical package with customized code. Dimensionality reduction was required for processing the large datasets: eight of the 17 measured variables were selected based on inspection of the correlation matrix. Data from four subsamples from each of the 56 samples produced using "in-house" methods were analyzed using ANOVA to assess the within- and between-sample variation. High within-sample variation was noted; however, ANOVA and post-hoc Tukey's honestly significant difference (HSD) tests demonstrated that the between-sample variation was substantially larger than the within-sample variation. Each sample could be differentiated from all other samples in the test set. Future experiments will focus on ways to reduce the within-sample variation, and additional statistical and microanalytical methods to classify sources and confidently constrain the method of Al powder manufacture.

Selective Phase Transfer Reagents (OxP-crowns) for Chromogenic Detection of Nitrates Especially Ammonium Nitrate.

Nitrogen and phosphorus-containing ions such as ammonium, nitrates and phosphates are anthropogenic pollutants while ammonium nitrate may be diverted for nefarious purposes in improvised explosive devices. Crown ether-oxoporphyrinogen conjugates (OxP-crowns) are used to selectively detect nitrates, especially their ion pairs with K+ and NH4 + , based on ion pair complexation of OxP-crowns under phase transfer conditions. The presence of phosphate and carbonate lead to deprotonation of OxP-crowns. OxP-1N18C6 is capable of extracting ion pairs with nitrate from aqueous phase leading to a selective chromogenic response. Deprotonation of the OxP moiety leads to [OxP- ]-1N18C6[K+ ] and is promoted by crown ether selective cation binding coupled with hydration of basic oxoanions, which are constrained to remain in the aqueous phase. This work illustrates the utility of molecular design to exploit partitioning and ion hydration effects establishing the selectivity of the chromogenic response.

Cover Feature: Selective Phase Transfer Reagents (OxP‐crowns) for Chromogenic Detection of Nitrates Especially Ammonium Nitrate (Chem. Eur. J. 58/2020)

A color-based detector for ammonium nitrate consists of crown ether-appended oxoporphyrinogens, the OxP-Crowns, which extract ion pairs into an organic phase based on cation binding at crown ether and anion complexation. Selective mauve chromogenic response is observed when ammonium nitrate, commonly used in improvised explosive devices, is extracted from water to chloroform providing a simple test. As illustrated, a network of responses is found when considering other anions and aqueous phase pH. More information can be found in the Full Paper by J. P. Hill et al. on page 13177.

Behaviour of a blast-driven ball bearing embedded in rear detonated cylindrical explosive

This paper presents insights into the flight characteristics of a ball bearing embedded in a rear detonated cylindrical charge, which represents an idealised piece of shrapnel from an improvised explosive device. A novel experimental technique was developed to quantify the loading from a blast-driven ball bearing. The impulse contributions from the blast pressure and the ball bearing impact were separately identifiable in the experimental data. Computational simulations, validated using experimental data, were used to elucidate additional detail about the momentum transfer and damage in the ball bearings during the blast event. The results show the critical influence of charge mass and aspect ratio on the development of the detonation pressure profile, its interaction with the embedded bearing, and the flight characteristics of the bearing. Length-to-diameter ratios below a critical value were more efficient in transferring momentum to the embedded bearings. These findings provide unique and detailed insights that will prove valuable to blast protection engineers considering the effects of embedded projectiles in improvised explosive devices.

The recovery of touch DNA from RDX-C4 evidences

RDX (Royal Demolition Explosive) is the organic compound with the formula (O2NNCH2)3. It is a white solid material without smell or taste, widely used as an explosive. It is more energetic explosive than TNT, and it was used widely in World War II. The estimated number of RDX-C4 cases in Bahrain ranged between the years 2015–2018 (May) with a total quantity of 370.72 KG in a total number of 38 cases. The effect of explosive RDX-C4 is very massive and can cause many causalities and fatalities among civilians and policemen. These cases consisted of adhesive film with tapes wrapped around RDX-C4 substance (Demolition Charge M112), black batteries, pipes, black bag contained RDX-C4, and in magnetic improvised explosive device (IED). Touch DNA recovery utilized different collection methods, such as nylon swabbing, tape lifting, and direct cutting of certain parts of the samples that were positive of RDX-C4 through DXR Raman Spectrometer. Samples were extracted and purified with magnetic beads chemistry and quantified. Low copy DNA extracts were subjected to a concentration step. DNA extracts were amplified and processed for detection to obtain reliable results using GlobalFiler Amplification PCR kit and run through ABI 3500xL Genetic Analyzer for fragment length determination. We have discovered that RDX-C4 cannot bind to the DNA nor to the solutions used in DNA typing. Thus, it does not cause DNA inhibition or degradation. From this point of view, we were successful in obtaining acceptable and fit results using advanced techniques. This study will be very useful and informative to assist the forensic community in terrorism case applications worldwide as terrorists do not respect geographical boundaries nor ethnicities of the victims, and the use of DNA profiling technology is the most suitable way to identify the terrorists and keep an end to their violence.

Hindfoot blast injuries caused by improvised explosive devices: long-term functional assessment in French military personnel.

The chosen treatment and long-term evaluation of hindfoot blast injuries are not well-represented in the literature. The first objective of this retrospective study was to evaluate functional outcomes in French service personnel who had sustained such injuries caused by improvised explosive devices. The second objective was to compare the results for patients who had amputations with those who did not. The hypothesis was that amputee recovered better function. Long-term functional evaluations were carried out using the American Orthopaedic Foot and Ankle Society scale (AOFAS), the Foot and Ankle Ability Measure (FAAM), and the Short Form 12 health survey (SF-12). Eight servicemen with ten hindfoot blast injuries were reviewed at a mean follow-up time of seven years. Primary management was always conservative although half of the patients required late amputation for chronic pain. The patients who underwent amputation reported significantly lower levels of pain than those who did not have an amputation, with higher FAAM and SF-12 scores. In this series, long-term functional results appear better in the amputated group.

Survival of forensic trace evidence on improvised explosive devices: perspectives on individualisation

Improvised Explosive Devices (IEDs) are weapons of modern times, used by terrorist groups and thereby causing substantial damage to communities. There is a widespread misconception that destructive conditions like heat, water or pressure destroy all forensic evidence. Moreover, the plausibility to detect identifiable fingermarks and DNA on components of IEDs is insufficiently known. Therefore, this study investigated the effects of neutralisation and explosion on latent fingerprints and touch DNA. In a majority of the cases, comparative fingermark- and DNA testing resulted in individualisation. In some cases, despite extremely low amounts of contact DNA detected after deployment of render-safe tools or detonation, full STR profiles could be constituted, even after applying fingerprint development techniques. This research shows that latent fingerprints and touch DNA on improvised explosives can be successfully detected after destructive conditions and possibly be linked to the perpetrators of such crimes. This individualising power offers perspectives to enhance forensic investigations of terrorism-related crimes.

Highly efficient fluorescent film probe of hydrogen peroxide vapor

Because of the increasing use in improvised explosives and serious influences on the public society, peroxide-based explosives are vital targets for detection. Herein, we reported two new fluorescent compounds, DB-WCZ and DB-W, served as turn-off type fluorescent film probes to H2O2 (a typical substitute for TATP) vapor. Both of DB-WCZ and DB-W are fluorene-pyrene compounds linked two borate ester units. The deboronation was contributed to the fluorescence quenching during the H2O2 detecting process. Compared with DB-W, DB-WCZ film shows higher selectivity and sensitivity to H2O2 vapor. The quenching rate can play up to 62% in 120 s and the fluorescent detection limit of DB-WCZ can be as low as 2.2 ppb, which might be due to the pendent carbazole units to DB-WCZ to form the porous microstructures and benefit the diffusion of H2O2 vapor.

Detection of fuel-oxidizer explosives utilizing portable capillary electrophoresis with wipe-based sampling.

Portable analytical instrumentation that can provide an alarm indication for the presence of explosives and related components is critical for the identification of explosives-based hazards and threats. Many explosives incident reports involve an inorganic oxidizer-fuel mixture which can include pyrotechnics, fireworks, flash powders, black powders, black powder substitutes, and improvised or homemade explosives. A portable CE instrument with targeted analysis of common inorganic oxidizer ions, for example, chlorate, perchlorate, and nitrate, was used here as a rapid detection platform. Unlike frequently used gas-phase separation and detection instrumentation such as ion mobility spectrometry (IMS), an automated liquid extraction mechanism is required for CE separation using acetate paper sample collection wipes. Target inorganic oxidizers were inkjet-printed onto sample wipes to investigate instrument response relative to the collected analyte spatial distribution. Overall, analyte signal intensities increased with off-center sample deposition due to improved sample extraction from wipes and no change in response was observed for varied array distributions across wipes. The system demonstrated sub 200ng detection limits for all target analytes, with further improvement when normalizing to an internal standard.

Impact Study on Composite Targets by a Nylon Projectile

In the present paper, impact study of nylon projectile on composite targets using a water-jet disruptor was addressed with damage mechanism. The three different composite targets such as teak, ply and pine woods were used in the experiment. The strength of wood and the damage under impact load is very crucial. The failure under load is very intricate as it is made up of natural composite. The composite target damage mechanism depends on characterisation and impact velocity of projectile. Simultaneously stresses and strains are generated which makes it responsible to cause the damage. Disruptor using water-jet plays a very crucial role in neutralising Improvised Explosive Devices (IEDs) with the minimum risk. These devices are designed to generate a high velocity water-jet using an electrically initiated gas generator cartridge. This helps in separating the critical components of IED’s and avoiding them from operating as anticipated. The damage caused by a waterjet disruptor is not quantified in assessing the performance. However, at present no technique was available to evaluate the performance. The terminal ballistics tests at the target end are found appropriate for solid projectiles, such as penetration of bullet into target plates or impact of fragments. These terminal effects are the good indicators considering the destruction. The available alternative measurement techniques are cost effective that forms a basis for future common test protocols. The authors suggested that craters made by a nylon projectile using the disruptor provide a quantitative measure. This should be considered as a potential for upcoming standard test for evaluating the performance. The impact caused by a nylon projectile is dependent on projectile kinetic energy and the dissemination of stress wave in the surrounding zone. The energy dissipated by a nylon projectile gets absorbed by the targets through a certain mechanisms. Ballistic velocities for various targets are also worked out. Pinewood has less ballistic velocity limit as compared to other two targets. Study and methods for the disruptor performance on various composite targets (plywood, teak wood and pinewood with 15 mm thickness) at 0.5 and 1m stand-off distances are evaluated. This compares with the respective common target tests. From the experiments, it is concluded that a nylon projectile has potential to penetrate through composite targets.

Estimation of Recoil Energy of Water-Jet Disruptor

Water is used as a liquid projectile in a disruptor for destruction of various dangerous objects such as improvised explosive devices (IED’s). This weapon is light weight and experiences certain recoil during a firing action. As there is motion between a projectile and a barrel, a recoil is experienced by the weapon. The recoil of weapon works on a conservation of momentum equation which is based on Newton’s second law of motion. A water-jet is created due to intense gas generation by a propellant burning inside the cartridge. The gas energy obtained by burning the propellant is responsible for pushing the projectile in a forward direction through the barrel. Due to gas generation by propellant burning, there is forward motion of the projectile. An attempt is made to determine the theoretical recoil velocity, its energy for the projectile in a water-jet application. The minimum and maximum recoil velocities of a water-jet varies from 2.311 m/s to 2.611 m/s. The order of magnitude for the recoil velocities is small and can be compared with a recoil of small calibre weapons that these weapons experienced during a firing mode. Based on recoil velocities, minimum and maximum kinetic energies of recoil parts are determined as 3.73 kJ and 4.77 kJ, respectively. The maximum gas force experienced by the projectile is worked out as 13.46 kN. The minimum and maximum energies to overcome the resistance force are determined as 14.657 J and 18.711 J, respectively. A small exercise for spring design is also covered.

Utøya – Christchurch – Halle. Right-wing Extremists’ Terrorism

The article deals with three terrorist attacks of right-wing extremists: in Norway (2011), New Zealand (2019) and Germany (2019). First, the modus operandi of perpetrators was shown and the course of each attack was analyzed. It was indicated what tactics the attackers used and why it was or was not effective. Secondly, the ideological background and motivations of the perpetrators were shown. It was possible to analyze the manifestos that the perpetrators left, and thus their way of thinking, their ideologies, and the purposes of organizing the attacks. Thirdly, issues related to the publicizing of the attacks by the perpetrators were shown. The goal of the article is to show that radical ideology of right-wing extremists (expressed in manifestos) leads to tragedies. In analyzed cases radical appointment of the perpetrators caused three deadly attacks. The article shows that the radical actions are preceded by radical speech, expressions, manifestos. The second goal is to pay attention to hate speech (also expressed in manifestos), which is just as dangerous as bullets or improvised explosive devices. The third goal is to show how the attackers used acts of terror to spread the ideologies to which they were devoted.

Light Weight Aluminum Cartridge Case Design for IED’s Application - ANSYS

This paper describes the design analysis of the aluminum cartridge case, its testing, Analytical Simulation (ANSYS) and evaluation against Improvised Explosive Devices (IEDs) applications. Aluminum material is light in weight, non-corrosive and compatible with the propellant. Because of excellent properties, it is widely used in defence application sector. In the armament system, an effort is being made to reduce the cost, the weight of material from logistic point of view and its manufacturing process so as to meet the design requirements. Brass cartridge cases are being widely used in various types of ammunition for last 100 years e.g. armaments of small arm cartridges, artillery shell and power cartridges for fighter aircraft. Cartridges are made of either aluminum, steel or brass is filled with the propellants and pyrotechnic composition. With suitable means of ignition, the propellant generates the hot combustion gases at high pressure and temperature. These combustion gases are utilized to perform certain work on the system. The aluminum cartridge case for water disruptor applications plays a significant role in the destruction of the suspicious objects. This paper discusses the design aspects of the aluminum cartridge case for disruptor application of suspected IEDs. Performance evaluation parameters i.e. maximum pressure (Pmax) and time to reach maximum pressure (TPmax) of aluminum cartridge have been carried out in a Closed Vessel (CV) using a Data Acquisition System (DAS). The material properties of aluminum such as tensile strength, percentage elongation and yield strength are determined using a Universal Testing Machine (UTM). Using the data obtained by the above methods, an attempt has been made to determine stress, strain and deformation of the cartridge case theoretically and numerically using ANSYS software. The results obtained by both methods are compared. The results are in good agreement with each other. It is observed that the percentage error for von -Mises stresses is 10.2 % using numerical and theoretical approaches. The percentage error between numerical and theoretical values of the hoop and longitudinal stresses are 6.71 % and 6.78 %. The percentage error between numerical and theoretical values of the hoop and longitudinal strains are 1.36 % and 3.64 %. The errors between theoretical and numerical values for radial displacements are 2.83 %. The novelty in this research work is that the design analysis of aluminium cartridge case is carried out using ANSYS software simulating the real- world problem. The analytical results are compared with numerical results. The actual pressure experienced by the cartridge case generated by the propellant burning is taken into consideration. This pressure is measured by a pressure transducer fitted over a specially designed test rig using a DAS. The sample of aluminum case is tested for hardness and microstructure. The results show there is no significant difference before and after the hardness and microstructure of the material. The results of ANSYS for stress and strain are in good agreement with theoretically calculated results and numerical analysis as percentage error is less than 11. This draws the inference for validating numerical and theoretical results. It is seen that 57.352 % saving in weight using aluminum cartridge is achieved. Using ANSYS, hoop stress 382.7 MPa, Hoop strain 4.32x10-3, longitudinal strain 0.8602x10-3 and longitudinal stress 191.5 MPa are estimated. The main objective of this paper is to carry out design and analysis of aluminum cartridge case analytically as well as numerically.