Trace explosives

This review summarizes (i) compositions and types of improvised explosive devices; (ii) the process of collection, extraction and analysis of explosive evidence encountered in explosive and related cases; (iii) inter-comparison of analytical techniques; (iv) the challenges and prospects of explosive detection technology. The highlights of this study include extensive information regarding the National & International standards specified by USEPA, ASTM, and so on, for explosives detection. The holistic development of analytical tools for explosive analysis ranging from conventional methods to advanced analytical tools is also covered in this article...

The role of ambient oxygen gas (O2) on molecular and nanoparticle formation and agglomeration was studied in laser ablation plumes. As a lab-scale surrogate to a high explosion detonation event, nanosecond laser ablation of an aluminum alloy (AA6061) target was performed in atmospheric pressure conditions. Optical emission spectroscopy and two mass spectrometry techniques were used to monitor the early to late stages of plasma generation to track the evolution of atoms, molecules, clusters, nanoparticles, and agglomerates...

Nitroaromatic compounds are common explosives and toxic pollutants, the selective and sensitive detection of which is of great importance. Herein, a facile and sensitive fluorescent sensor L was constructed for the sensing of TNP based on the hexahomotrioxacalix[3]arene skeleton. The fluorescence emission of L was drastically quenched in the presence of 2,4,6-trinitrophenol (TNP), while other tested NACs, metal ions, and anions induced negligible changes. Under the optimized conditions, the spectroscopic studies revealed that L exhibited extremely sensitive and selective TNP recognition, with a detection limit of 9...

Organic semiconductors can be applied as ultra-sensitive fluorescent sensors for detecting trace vapours of explosives. The detection of explosives is manifest by the fluorescence quenching of the sensors. However, for many organic fluorescent sensors, the fluorescence quenching is irreversible and imposes a limitation in terms of reusability. Here we present a study of the thermal control of thin-film fluorescent sensors made from the commercial fluorescent polymer Super Yellow (SY). Thermal control of the sensor's temperature results in the desorption of the absorbed analytes, nitroaromatic explosives (2,4-DNT and DNB), and a taggant molecule (DMDNB)...

Anger is a powerful and mostly deleterious emotion that can impair an individual's health and social relationships and that imposes considerable costs on society at large. It is a constituent of multiple psychopathologies, most notably intermittent explosive disorder. Excessive anger can drive injurious and even lethal reactive aggression. To understand its biobehavioral origins and develop appropriate therapeutic interventions, an animal model of human anger would be quite useful. The phenomena of aggression provoked by frustrative nonreward (FNR) in other animals, including species of fish, birds, and mammals, resemble those in people in whom it elicits subjectively experienced anger...

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...

BACKGROUND: A growing body of research has found a link between firearm availability and police shootings of citizens across place. The problem, however, is that the previous studies on the topic tend to suffer from several limitations: a near exclusive focus on citizen fatalities, units of analysis at the state or county levels, and a variety of proxy measures tapping into community-level firearm access. The current study set out to address these issues by examining the relationship between different forms of firearm availability and both fatal and nonfatal injurious police shootings of citizens at the city level...

Triacetone triperoxide (TATP) is a high-power explosive which is often used by criminals. The detection of TATP is of great significance for solving the explosion cases. However, the preconcentration and analysis of trace levels of TATP still pose challenges for analytical researchers. In this study, metal-organic frameworks (MOFs), including IRMOF-8, MOF-5, UIO-66, ZIF-8, and MIL-101(Cr), were immobilized on a stainless steel wire using a physical adhesive method as a solid-phase microextraction (SPME) fiber coating...

Due to the characteristics of peroxide explosives, which are difficult to detect via conventional detection methods and have high explosive power, a fluorescent photoelectric detection system based on fluorescence detection technology was designed in this study to achieve the high-sensitivity detection of trace peroxide explosives in practical applications. Through actual measurement experiments and numerical simulation methods, the derivative dynamic time warping (DDTW) algorithm and the Spearman correlation coefficient were used to calculate the DDTW-Spearman distance to achieve time series correlation measurements...

Among the many commonly encountered hazards, improvised explosive devices (IEDs) remain the primary threat to military and civilian personnel due to the ease of their production and the widespread availability of their raw materials and precursors. Identifying traces of potential precursors is the first step in developing appropriate control measures. An interesting approach is to identify the precursors that are released around the site as they are handled and transformed into the final IEDs. CO2 laser photoacoustic spectroscopy can offer the spectral characterization of a number of explosives-related compounds without sample preparation...

Detection of landmines without harming personnel is a global issue. The bacterial transcription factor YhaJ selectively detects metabolites of explosives, and it can be used as a key component of DNT biosensors. However, the wild-type YhaJ has a binding affinity that is not sufficient for the detection of trace amounts of explosives leaked from landmines buried in the soil. Here, we report crystal structures of the effector-binding domain of YhaJ in both the apo- and effector-bound forms. A structural comparison of the two forms revealed that the loop above the primary effector-binding site significantly switches its conformation upon effector binding...

BACKGROUND: Drosophila melanogaster is excellent animal model for understanding the molecular basis of human neurological and motor disorders. The experimental conditions and chamber design varied between studies. Moreover, most previously established paradigms focus on fly trace detection algorithm development. A comprehensive understanding on how fly behaves in the chamber is still lacking. RESULTS: In this report, we established 74 unique behavior metrics quantifying spatiotemporal characteristics of adult fly locomotion and social behaviors, of which 49 were newly proposed...

Preconcentration for on-site detection or subsequent determination is a promising technique for selective sensing explosive markers at low concentrations. Here, we report divinylbenzene monolithic polymer in its blank form (neat-DVB) and as a composite incorporated with sodalite topology zeolite-like metal-organic frameworks (3-ZMOF@DVB), as a sensitive, selective, and cost-effective porous preconcentrator for aliphatic nitroalkanes in the vapor phase as explosive markers at infinite dilution. The developed materials were fabricated as 18 cm gas chromatography (GC) monolithic capillary columns to study their separation performance of nitroalkane mixture and the subsequent physicochemical study of adsorption using the inverse gas chromatography (IGC) technique...

Over the twentieth century, the concept of the natural experiment has become increasingly prominent across a variety of disciplines, albeit most consequentially in epidemiology and public health. Drawing on an analysis of the scientific and medical literature, we explore the social life of the natural experiment, tracing its changing use, meaning and uptake to better understand the work done by the concept. We demonstrate how the natural experiment became central to the identity of post-war epidemiology as the discipline professionalised, turned its attention to the prevention of chronic disease and took centre stage in the field of public health...

Many residents of the Russian Southern Urals were exposed to radioactive environmental pollution created by the operations of the Mayak Production Association in the mid- 20th century. There were two major releases: the discharge of about 1x1017 Bq of liquid waste into the Techa River between 1949 and 1959; and the atmospheric release of 7.4 * 1016 Bq as a result an explosion in the radioactive waste-storage facility in 1957. The releases into the Techa River resulted in the exposure of more than 30,000 people who lived in riverside villages between 1950 and 1961...

A palaeontological analysis of the evolutionary steps of Metazoa is tracing back the appearance and first steps of information behaviour as far as the Proterozoic Eon. Either the neural cell or the nervous system or the eyesight did not trigger the appearance of the information behaviour, but it did a novel way of diet. Carnivorous diet appeared on Earth slightly before the information behaviour as a completely new way of feeding - and what is more important: the application of light into the behavioural complexes as a radically innovative survival supporting tool...

Instant detection of explosive material is highly appreciated for counterterrorism activity and homeland security. Nitro group (high energy rich bond) is responsible for explosive characteristics. Nitro group includes intense competition between two highly electronegative atoms. Nitro group is frequently encountered in all explosive materials. This function group includes delocalized π bond; that could secure intense photoluminescence (fluorescence and phosphorescence) signature. In this study, the main classes of explosive materials including nitro-compounds (i...

Viscous flows through pipes and channels are steady and ordered until, with increasing velocity, the laminar motion catastrophically breaks down and gives way to turbulence. How this apparently discontinuous change from low- to high-dimensional motion can be rationalized within the framework of the Navier-Stokes equations is not well understood. Exploiting geometrical properties of transitional channel flow we trace turbulence to far lower Reynolds numbers (Re) than previously possible and identify the complete path that reversibly links fully turbulent motion to an invariant solution...

Fluctuations in ultra high purity (UHP) helium supply has the potential to negatively impact critical research efforts. Disruptions have increased significantly with suppliers prioritizing delivery to medical facilities. Due to the greater demand for helium, supply issues are likely to continue through the coming years. Many gas chromatography (GC)-based analytical methods rely on the supply of UHP helium, including those developed for the quantification of trace explosives. Vapor validation is critical in establishing sensor performance, limits of detection, and instrument performance...

The development of an electronic nose (E-nose) for rapid explosive trace detection (ETD) has been extensively studied. However, the extremely low saturated vapor pressure of explosives becomes the major obstacle for E-nose to be applied in practical environments. In this work, we innovatively combine the decomposition characteristics of nitro explosives when exposed to ultraviolet light into gas sensors for detecting explosives, and an E-nose consisting of a SnO2 /WO3 nanocomposite-based chemiresistive sensor array with an artificial neural network is utilized to identify trace nitro-explosives by detecting their photolysis gas products, rather than the explosive molecules themselves or their saturated vapor...