Search Results (13)

Homemade explosives (HMEs) are of increasing interest to security forces worldwide due to their widespread utilization by terrorists. Their synthesis is relatively straightforward, requiring only a few readily available chemical compounds. Among the most popular HMEs are organic peroxides, specifically triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD). This manuscript reports on a paper-based sensor developed for the detection of HMTD. The sensor facilitates fast, inexpensive, and simple detection of this peroxide. The developed sensor was compared with well-established commercial and in-house-developed iodometric tests typically used for peroxide determination. The colorimetric principle was based on the use of a potassium iodide and citric acid solution applied to a paper substrate. The HMTD and TATP samples were prepared in an acetone–water mixture (1:1, v/v). The sensor was able to detect HMTD down to a limit of 0.01 mg/mL. The developed sensor does not exhibit cross-reactivity with other explosives, including TATP. Furthermore, an HSV analysis of the photographs was performed using the Trigit application. Full article

Although the accidental or intentional explosions produced in industrial facilities or in urban areas are events with low probability, they have a high destructive potential and potential for human injuries and/or fatalities. One of the types of such events is given by detonation of improvised explosive devices (IEDs)—dirty bombs for terrorist purposes—which may produce a high number of metallic fragments. Studying mass and spatial distributions of these fragments is useful for evaluating their lethality and destructive potential and may help to implement adequate protective measures. This work brings a closer insight into the fragment dispersion around the detonation of a steel-enclosed C4 charge with cylindrical symmetry. In this respect a specific approach involving both detonation experiments and numerical simulations performed by home-made and commercial software packages for investigation of the fragmentation process and accompanying angular scattering of the fragments was proposed. Special algorithms, which allow the estimation of the spatial distributions of fragments from the numerical analysis of perforations made by the metallic fragments generated by such IEDs on surrounding material walls, are developed. Further, numerical simulations of a similar IED device provided output parameters related to the statistical distributions of mass, kinetic energy and position of the fragments. Experimental fragmentation generated a recovered mass distribution (94 fragments of 67.5 g) that was compared with that extracted from simulation, revealing a reasonable agreement on the 0.3–1 g range. In the case of simulations, 300 fragments from a total number of 374 showed a mass ranging from 0.004 to 0.3 g. The simulations showed that the middle part of the steel case generated fragments of kinetic energy over 4 kJ and its ends generated fragments of kinetic energy under 1 kJ. Experimental fragment scattering distributions were investigated with specific home-made numerical algorithms, which, based on a set of images, analysed the correlations between spatial coordinates of perforations made by fragments on surrounding special panels and provided histograms that are discussed in relation with the fragment-induced lethality degree. Full article

Firework-related injuries remain a serious public health issue in Germany, especially during New Year’s Eve. While many injuries are minor, the misuse of illegal or homemade fireworks can cause severe trauma resembling military combat injuries and can heavily burden emergency services. Notably, injury rates declined during the COVID-19 firework bans, underscoring the impact of preventive measures. We report two cases of young males with severe injuries from illicit fireworks. The first is a case of a 16-year-old that detonated an illegal Polish firework ball bomb, sustaining 9% total body surface area (TBSA) burns (second- to third-degree), hand fractures, compartment syndrome of the hand, and soft-tissue trauma. He underwent multiple surgeries, including fasciotomy, osteosynthesis, and skin grafting. The other case presented is a 19-year-old man who was injured by a homemade device made of bundled firecrackers, suffering deep facial and bilateral hand burns. He required prolonged ventilation, surgical debridement, and treatment with Kerecis^® fish skin and Epicite^® dressings. Both required intensive ICU care, interdisciplinary management, and lengthy rehabilitation. Total hospital costs amounted to €58,459.52 and €94,230.23, respectively, as calculated according to the standardized German DRG. These cases illustrate the devastating impact of illegal fireworks. The devastating consequences of explosive trauma are often difficult to treat and may lead to long-term functional and psychological impairments. Prevention through public education, stricter regulations, and preparedness is essential. Pandemic-era injury reductions support sustained policy efforts. Full article

Metal-containing compounds form a large and rapidly expanding group of high-energy materials. Many compounds in this class attract the attention of non-professionals, who may attempt the illegal production of explosives. Several of these substances have been commercially available and pose significant danger if used by terrorists or for criminal purposes. Others are experimental compounds, kinds of curiosities, often created by pyrotechnics enthusiasts, which can present serious risks to both the creators and their immediate surroundings. The internet hosts a vast amount of information, including recipes and discussions on forums, private websites, social media, and more. This paper aims to review the variety of metal-containing explosives and discuss their appeal and potential accessibility to unauthorized individuals. Full article

The chemical industry explosion in the 20th century has led to increased environmental pollution, affecting fauna, flora, and waterways. These substances alter water’s taste, color, and smell, making it unfit for consumption or toxic. Agricultural water networks face threats from pollution before and after treatment. Some chemical contaminants, like pesticides, are embedded in natural biogeochemical cycles. In this study, we developed a simple and low-cost procedure for the fabrication of needles coated with polydimethylsiloxane (PDMS) as an efficient sorbent for the microextraction of organic pollutant traces from water. The prepared needles were used as an alternative for commercial solid-phase micro-extraction (SPME) devices in analytical chemistry. The PDMS polymeric phase was characterized by Fourier-transform infrared spectroscopy (FT-IR), thermogravimetry (TGA), and scanning electron microscopy (SEM). The PDMS-coated needles were used for extraction of thirteen pesticides by direct-immersion solid-phase microextraction (DI-SPME) from contaminated waters, followed by determination with gas chromatography-mass spectrometry (GC-MS). The developed analytical method showed limits of detection (LODs) between 0.3 and 2.5 ng mL⁻¹ and RSDs in the range of 0.8–12.2%. The homemade needles were applied for the extraction of pesticides in surface and ground aqueous samples collected from an agricultural area. Several target pesticides were identified and quantified in the investigated water samples. Full article

Detecting trace amounts of explosives is important for maintaining national security due to the growing threat of terror attacks. Particularly challenging is the increasing use of homemade explosives. Therefore, there is a constant need to improve existing technologies for detecting trace amounts of explosives. This paper describes the design of a stationary device (a gate) for detecting trace amounts of explosives and explosive taggants and the design of differential ion mobility spectrometers with a focus on the gas system. Nitromethane (NM), trimeric acetone peroxide (TATP), hexamine peroxide (HMTD), and explosive taggants 2,3-dimethyl-2,3-dinitrobutane (DMDNB) and 4-nitrotoluene (4NT) were used in this study. Gate measurements were carried out by taking air from the hands, pocket area, and shoes of the tested person. Two differential ion mobility spectrometers operating in two different modes were used as explosive detectors: a mode with a semi-permeable membrane to detect explosives with high vapor pressures (such as TATP) and a mode without a semi-permeable membrane (using direct introduction of the sample into the measuring chamber) to detect explosives with low vapor pressures (such as HMTD). The device was able to detect trace amounts of selected explosives/explosive taggants in 5 s. Full article

There is an ongoing forensic and security need for rapid, on-scene, easy-to-use, non-invasive chemical identification of intact energetic materials at pre-explosion crime scenes. Recent technological advances in instrument miniaturization, wireless transfer and cloud storage of digital data, and multivariate data analysis have created new and very promising options for the use of near-infrared (NIR) spectroscopy in forensic science. This study shows that in addition to drugs of abuse, portable NIR spectroscopy with multivariate data analysis also offers excellent opportunities to identify intact energetic materials and mixtures. NIR is able to characterize a broad range of chemicals of interest in forensic explosive investigations, covering both organic and inorganic compounds. NIR characterization of actual forensic casework samples convincingly shows that this technique can handle the chemical diversity encountered in forensic explosive investigations. The detailed chemical information contained in the 1350–2550 nm NIR reflectance spectrum allows for correct compound identification within a given class of energetic materials, including nitro-aromatics, nitro-amines, nitrate esters, and peroxides. In addition, the detailed characterization of mixtures of energetic materials, such as plastic formulations containing PETN (pentaerythritol tetranitrate) and RDX (trinitro triazinane), is feasible. The results presented illustrate that the NIR spectra of energetic compounds and mixtures are sufficiently selective to prevent false-positive results for a broad range of food-related products, household chemicals, raw materials used for the production of home-made explosives, drugs of abuse, and products that are sometimes used to create hoax improvised explosive devices. However, for frequently encountered pyrotechnic mixtures, such as black powder, flash powder, and smokeless powder, and some basic inorganic raw materials, the application of NIR spectroscopy remains challenging. Another challenge is presented by casework samples of contaminated, aged, and degraded energetic materials or poor-quality HMEs (home-made explosives), for which the spectral signature deviates significantly from the reference spectra, potentially leading to false-negative outcomes. Full article

During the armed conflict in Colombia, homemade improvised antipersonnel landmines were used to neutralize the adversary. Many active artifacts remain buried, causing damage to biodiversity by exploding. The extensive literature describes the effects and injuries caused to humans by conventional landmines. However, there is considerably less information on the behavior and effects of homemade antipersonnel landmines on fauna and good field investigation practices. Our objectives were to describe the characteristics of a controlled explosion of a homemade antipersonnel landmine (using ammonium nitrate as an explosive substance), to compare the effectiveness of some evidence search patterns used in forensic investigation, and to determine the effects on a piece of an animal carcass. The explosion generated a shock wave and an exothermic reaction, generating physical effects on the ground and surrounding structures near the point of explosion. The amputation of the foot in direct contact with the device during the explosion and multiple fractures were the main effects on the animal carcass. Finally, it was determined that finding evidence was more effective in a smaller search area. Many factors can influence the results, which must be weighed when interpreting the results, as discussed in this manuscript. Full article

A novel sample introduction and ionization method for trace explosives detection is proposed and investigated herein, taking into consideration real-world application requirements. A thermal desorption sampling method and dielectric barrier discharge ionization (DBDI) source, with air as the discharge gas, were developed. The counter flow method was adopted firstly into the DBDI source to remove the interference of ozone and other reactive nitrogen oxides. A separated reaction region with an ion guiding electric field was developed for ionization of the sample molecules. Coupled with a homemade miniature digital linear ion trap mass spectrometer, this compact and robust design, with further optimization, has the advantages of soft ionization, a low detection limit, is free of reagent and consumable gas, and is an easy sample introduction. A range of common nitro-based explosives including TNT, 2,4-DNT, NG, RDX, PETN, and HMX has been studied. A linear response in the range of two orders of magnitude with a limit of detection (LOD) of 0.01 ng for TNT has been demonstrated. Application to the detection of real explosives and simulated mixed samples has also been explored. The work paves the path to developing next generation mass spectrometry (MS) based explosive trace detectors (ETDs). Full article

Ammonium perchlorate (AP) is a common oxidant in solid propellants, and its thermal decomposition characteristics at low temperatures (less than 240 °C) are key to the study of the thermal safety of propellants. Here, the low-temperature thermal decomposition characteristics of AP were investigated at 230 °C. The micromorphology of the low-temperature decomposition residues was characterized by scanning electron microscopy and 3D nano-computed tomography in order to analyse the evolution of microscopic pore structures, and the effect of the AP pore structure on combustion performance was then tested and analysed with a homemade closed bomb. The results demonstrate that the low-temperature decomposition of AP first occurs near the surface of the particles, simultaneously starting at multiple points and forming pores, and then gradually expands towards the interior until almost all of the pores connect with one other. Compared with ordinary AP, porous AP has a significantly improved combustion rate. When the ratio of porous AP to Al was 80:20, the peak pressure in the closed bomb was increased by 2.7 times; the rate of change in peak pressure increased 34 times, leading to a higher reaction speed and higher reaction intensity, and a typical explosion reaction occurred. Full article

Triacetone triperoxide (TATP) is a new terrorist explosive, and most nitrogen-based sensors fail to detect TATP. Herein, a sea urchin-like TiO₂-covered TiO₂ nanoarray is constructed as a TATP-sensitive homojunction (HJ) by one step hydrothermal method. By taking fluorine-doped tin oxide (FTO) and indium tin oxide (ITO) conducting glass as the substrate, the conducting glass is horizontally and vertically put in the reactor to epitaxially grow TiO₂–FTO, TiO₂–ITO, TiO₂–FTO–HJ and TiO₂–ITO–HJ. TiO₂–FTO–HJ shows a broad absorption band edge in the visible region and high sensitivity to TATP under the simulating natural light compared with TiO₂–FTO, TiO₂–ITO, and TiO₂–ITO–HJ. E-field intensity distribution simulation reveals that constructing homojunctions between the urchin-shaped TiO₂ nanosphere and TiO₂ nanoarrays can enhance the localized electromagnetic field intensity at the interface of junctions, which may provide photocatalysis active sites to reduce TATP molecules by promoting charge separation. Moreover, the TiO₂–FTO–HJ shows high selectivity to TATP among ammonium nitrate, urea and sulfur, which are common homemade explosive raw materials. Full article

Explosives detection systems (EDS) based on X-ray are used at airports to screen baggage for the presence of explosives. Once EDS are installed in airports, however, it can be challenging to test the EDS equipment and verify that it continues to perform at the highest level, because of the impracticality of introducing bulk explosives into civil aviation airports. The problem is particularly acute for sensitive homemade explosives, such as triacetone triperoxide (TATP). This paper describes our work to develop a safe, accurate and stable simulant for TATP for EDS based on X-ray transmission. Bulk quantities of TATP were synthesised and characterised especially for this project, and we describe the unique challenges and safety considerations of collecting this data. Our calculations show that the expanded measurement uncertainty with a coverage factor of k = 2 is 5.7% for bulk density and 1.0% for Zeff at 24 months. Full article

The homemade explosive, triacetone triperoxide (TATP), is easy to synthesize, sensitive to detonation but hard to detect directly. Vapor sensor arrays composed of a few sensor materials have the potential to discriminate TATP, but the stability of the sensor array is always a tricky problem since each sensor may encounter a device fault. Thus, a sensor array based on a single optoelectronic TiO₂/PW₁₁ sensor was first constructed by regulating the excitation wavelength to discriminate TATP from other explosives. By in situ doping of Na₃PW₁₂O₄₀, a Keggin structure of PW₁₁ formed on the TiO₂ to promote the photoinduced electron-hole separation, thus obviously improving the detection sensitivity of the sensor film and shortening the response time. The response of the TiO₂/PW₁₁ sensor film to TATP under 365, 450 and 550 nm illumination is 81%, 42%, and 37%, respectively. The TiO₂/PW₁₁ sensor features selectivity to TATP and is able to detect less than 50 ppb. The flexibility and stability of the flexible sensor film is also demonstrated with the extent of bending. Furthermore, the sensing response cannot be affected by ambient air below 60% relative humidity. Full article