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Under two detection schemes, this study analyzes one of the most destructive weather systems - the explosive cyclones - in the South Atlantic, from 2010 to 2020. Then, two methods are presented to study these systems: the Observational Method (OBSM) and the Automated Method (AUTM). The first uses visual analysis of the mean sea level pressure (mslp) fields and functions to identify the local minimums using the Grid Analysis and Display (GrADS) software. The second utilizes a function from OpenGrADS called mfhilo. It shows the local minimum in the grid using laplacian, magnitude, and percentile. Two shell algorithms for data manipulation are used for the AUTM: one to trace the cyclones' trajectories according to a previously defined fixed area and the other to separate them into explosives. The OBSM methodology showed 271 cases averaging 25 yearly and revealed important characteristics regarding the intensities. According to AUTM's methodology, from the 2705 ordinary cyclone cases identified, 299 are explosives. There is a clear seasonality pattern in the systems' distribution along South America, similar to OBSM, but more highlighted. In summer, they concentrate at high latitudes, while in winter and spring, they are assembled near southern Brazilian and Uruguayan coasts.

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Detection canines are deployed to detect explosives in a wide range of environmental conditions. These environmental conditions may have negative impacts on canine capabilities as a sensor. This study leveraged an air dilution olfactometer to present controlled odor concentrations of four different energetic materials (double base smokeless powder, Composition C4, ammonium nitrate, and flake Trinitrotoluene) to dogs working in a range of high temperature, standard, and low temperature conditions with high and low humidity conditions. The air dilution olfactometer controlled concentrations independent of environmental condition. Dogs' detection threshold limits were measured using a descending staircase procedure. We measured dogs' threshold twice for each energetic under each environmental condition. Results indicated heterogeneity in effects based on energetic, but all odors were detected at their lowest concentrations under standard conditions. Smokeless powder detection was reduced under all environmental conditions compared to standard and was least detectable under high temperature and humidity conditions. AN detection was poorest under high temperature high and low humidity conditions. C4 in contrast, was least detectable at low temperatures with high humidity. TNT detection was difficult under all conditions, so decrements due to environmental conditions were not statistically detectable. Additional measures were also found to be associated with detection limits. Under high temperature conditions, correlations were observed between canine mean subcutaneous temperature and detection limits, such that dogs experiencing greater temperature increases showed poorer detection limits. In addition, dog's latency to sample the odor port from the onset of a trial was longest in the high temperature conditions. Longer latencies were also predictive of poorer detection performance. Overall, dogs showed deficits in detection sensitivity limits under all environmental conditions for at least one energetic material when the concentration of that energetic material was not directly impacted by the environmental conditions. These results suggest that behavioral factors related to environmental exposure can have important impacts on canine detection sensitivity and should be considered in operational environments.

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In view of the current problems of slow crystallization rate, varying grain sizes, complex process conditions, and low safety in the preparation of CL-20/TNT cocrystal explosives in the laboratory, an opposite spray crystallization method is provided to quickly prepare ultrafine explosive cocrystal particles. CL-20/TNT cocrystal explosive was prepared using this method, and the obtained cocrystal samples were characterized by electron microscopy morphology, differential thermal analysis, infrared spectroscopy, and X-ray diffraction analysis. The effects of spray temperature, feed ratio, and preparation method on the formation of explosive cocrystal were studied, and the process conditions of the pneumatic atomization spray crystallization method were optimized. The crystal plane binding energy and molecular interaction forces between CL-20 and TNT were obtained through molecular dynamic simulation, and the optimal binding crystal plane and cocrystal mechanism were analyzed. The theoretical calculation temperature of the binding energy was preliminarily explored in relation to the preparation process temperature of cocrystal explosives. The mechanical sensitivity of ultrafine CL-20/TNT cocrystal samples was tested. The results showed that choosing acetone as the cosolvent, a spraying temperature of 30 °C, and a feeding ratio of 1:1 was beneficial for the formation and growth of cocrystal. The prepared CL-20/TNT cocrystal has a particle size of approximately 10 µm. The grain size is small, and the crystallization rate is fast. The impact and friction sensitivity of ultrafine CL-20/TNT cocrystal samples were significantly reduced. The experimental process conditions are simple and easy to control, and the safety of the preparation process is high, providing certain technical support for the preparation of high-quality cocrystal explosives.

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The utilization of ambient ionization (AI) techniques for mass spectrometry (MS) has significantly grown due to their ability to facilitate rapid and direct sample analysis with minimal sample preparation. This study investigates the performance of various AI techniques, including atmospheric solids analysis probe (ASAP), thermal desorption corona discharge (TDCD), direct analysis in real time (DART), and paper spray coupled to a Waters QDa mass spectrometer. The focus is on evaluating the linearity, repeatability, and limit of detection (LOD) of these techniques across a range of analytes, including amino acids, drugs, and explosives. The results show that each AI technique exhibits distinct advantages and limitations. ASAP and DART cover high concentration ranges, which may make them suitable for semiquantitative analysis. TDCD demonstrates exceptional linearity and repeatability for most analytes, while paper spray offers surprising LODs despite its complex setup (between 80 and 400 pg for most analytes). The comparison with electrospray ionization (ESI) as a standard method shows that ambient ionization techniques can achieve competitive LODs for various compounds such as PETN (80 pg ESI vs 100 pg ASAP), TNT (9 pg ESI vs 4 pg ASAP), and RDX (4 pg ESI vs 10 pg ASAP). This study underscores the importance of selecting the appropriate ambient ionization technique based on the specific analytical requirements. This comprehensive evaluation contributes valuable insights into the selection and optimization of AI techniques for diverse analytical applications.

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BACKGROUND: Direct detection of the notorious explosive triacetone triperoxide (TATP) is very difficult because it lacks facile ionization and UV absorbance or fluorescence. Besides, the current indirect methods are time-consuming and need a pre-step for TATP cleavage to hydrogen peroxide. Moreover, they commonly show significant false-positive results in the presence of some camouflage which limits their field applications. Herein, for the first time, a novel label-free field-applicable spectrofluorimetric nanobiosensor was developed for direct TATP detection using a novel activated-protein protected gold nanocluster (ABSA-AuNCs; QY = 28.3 %) synthesized by a combined protein-assisted-ultrasonication procedure. RESULTS: The ABSA-AuNCs revealed a fluorescence spectrum centered at 330.0 nm which was significantly quenched by TATP (binding constant = 154.06 M-1; ΔG = -12.5 kJ mol-1; E(%) = 88.5 %). This phenomenon was used as a basis for direct TATP quantification, providing a working range of 0.01-40.0 mg L-1 and a detection limit of 6.7 µg L-1 which is the lowest LOD provided for TATP detection up to now. A %RSD of 0.9 % and 1.56 % was obtained for repeatability and inter-day reproducibility, respectively. The selectivity was checked against a variety of camouflages, revealing ultra-selectivity. Several synthetic samples prepared by several camouflages and real samples (clay soil and real water media) were analyzed, revealing quantitative recoveries of TATP. SIGNIFICANCE: During the production of the notorious explosive TATP, it can be discharged into water and soil. This novel method eliminated the false-positive results of traditional methods and is applicable for direct quantitative detection of camouflaged TATP and its residues in real soil and water samples in a highly short response time (2 min). The camouflaged TATP analysis is important for tracking the terrorist attacks in field conditions and analysis of soil and water can provide a first indication of the location of the production site.

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In this work, energetic coordination compounds (ECCs) of transition metals (Fe, Ni, Cu, Zn) containing aliphatic amines as ligands were synthesized: ethylenediamine; 1,3-diaminopropane; tris(2-aminoethyl)amine; tris(3-aminopropyl)amine. The compounds were investigated in terms of ignition/explosion temperature, friction and impact sensitivity. For selected compounds, structural characterisation was presented (IR-ATR spectroscopy, Raman spectroscopy) and their morphology was determined (SEM, powder XRD). They were also investigated by differential scanning calorimetry (DSC). In order to assess the potential application of selected ECCs in detonators, underwater explosion tests were carried out, determining energetic performance. The results achieved for detonators containing ECCs were compared with those for reference detonators (containing pentaerythritol tetranitrate, PETN), indicating their potential use as a "green" alternative to nitric acid esters.

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The precise synthesis of Cu NCs is a highly desirable and controllable route for the preparation of desired structures and properties, which facilitates the rational design of valuable probes for fluorescence sensing and the understanding of structure-property relationships. Herein, an ion-exchange strategy combined with a bottom-up synthetic approach was utilized in the synthesis process of Cu NCs for the first time, which achieved the controllable synthesis of Cu NCs and in situ anchoring of Cu NCs on the support material HPU-14. The as-prepared Cu NCs@HPU-14-4h not only had a good peroxidase-like property but also exhibited stable dual-emitting fluorescence at 470 and 620 nm. Notably, the peroxidase-like property endowed Cu NCs@HPU-14-4h with the capability of highly sensitive colorimetric detection of H2O2 in a linear concentration from 0.1 to 140 µM (detection limit of 86.7 nM), and a change in the fluorescent color from red to blue could be observed by the naked eye. Furthermore, due to the large overlap between the absorption of 2,4,6-trinitrophenol (TNP) and the excitation band of Cu NCs@HPU-14-4h, TNP could also be detected from 27 types of analogs and common ions with a limit of detection of 68 nM. Finally, a portable hydrogel probe with efficient wipe sampling was fabricated by polyvinyl alcohol (PVA) comprising Cu NCs@HPU-14-4h with the aim of on-site visualization of different explosives. Consequently, the current study not only provides a new idea for the precise synthesis of Cu NCs and their controllable anchoring on support materials but also offers an effective method for predicting H2O2 and TNP.

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Military activities and the production or disposal of ammunition often lead to soil contamination with energetic compounds (ECs) such as dinitrotoluene, trinitrotoluene, and hexogen, posing significant threats to human health and the ecosystem. Biochar has emerged as a cost-effective and widely available solution for remediating contaminated sites characterized by its capacity for pollutant removal through adsorption and conversion process, along with minimal secondary pollution. This paper provides a comprehensive review of relevant literature on biochar's efficacy in eliminating ECs, including an analysis of the underlying mechanisms. The discussion addresses challenges and opportunities associated with biochar application in ECs remediation, offering insights for future research directions. In summary, the use of biochar for ECs removal presents a promising and eco-friendly approach, facilitating the remediation of contaminated sites while promoting soil function and ecosystem recovery.

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OBJECTIVE: To investigate the prevalence of firework-associated fear in dogs in Sydney, owner perception of their dog's response to fireworks, perceived efficacy of interventions to manage fearful behaviours and the frequency of dog owners seeking professional advice for these behaviours. METHODS: Dog owners in the Greater Sydney area were invited to complete an anonymous online survey. RESULTS: From 387 valid responses, 44.4% (171 of 385) reported their dogs were fearful of fireworks. The most common fear-related behaviour was seeking an owner or caretaker (120 of 161, 74.5%). Most owners responded by bringing their dog inside or trying to comfort or reassure their dog. Only 22.5% of owners sought professional advice for their dog's fear of fireworks, but of these, 65.5% considered that advice to be effective. Source and breed group were significantly associated with fear of fireworks (P = 0.011, P = 0.036 respectively). Fear of fireworks was also significantly associated with fear of thunder (P < 0.0001), gunshots (P < 0.0001) and vehicles (P = 0.0009). CONCLUSION: Fear of fireworks and other loud noises negatively impacts canine welfare, yet only a small percentage of owners sought professional advice. There is scope for veterinarians to educate owners and raise awareness about the identification and management of noise-associated fear and reduce the risk of escalation of fearful behaviours.

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A wearable glove-based sensor is a portable and practical approach for onsite detection/monitoring of a variety of chemical threats. Herein, we report a flexible and sensitive wearable sensor fabricated on the nitrile glove fingertips by stencil-printing technique. The working electrodes were modified with multiwalled carbon nanotubes (MWCNTs)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) for sensitive and real-time analyses of hazardous or chemical treats, as picric acid (PA) explosive, diazepam (DZ) as drug-facilitated crimes and the emerging pollutant 4-nitrophenol (4-NP). The multi-sensing platform towards PA, 4-NP, and DZ offers the ability of in-situ qualitative and quantitative analyses of powder and liquid samples. A simple sampling by touching or swiping the fingertip sensor on the sample or surface under investigation using an ionic hydrogel combined with fast voltammetry measurement provides timely point-of-need analyses. The wearable glove-based sensor uses the square wave voltammetry (SWV) technique and exhibited excellent performance to detect PA, 4-NP, and DZ, resulting in limits of detection (LOD) of 0.24 µM, 0.35 µM, 0.06 µM, respectively, in a wide concentration range (from 0.5 µM to 100 µM). Also, we obtained excellent manufacturing reproducibility with relative standard deviations (RSD) in the range of 3.65%-4.61% using 7 different wearable devices (n = 7) and stability in the range of 4.86%-6.61% using different electrodes stored for 10 days at room temperature (n = 10), demonstrating the excellent sensor-to-sensor reproducibility and stability for reliable in-field measurements. The stretchable sensor presented great mechanical robustness, supporting up to 80 bending or stretching deformation cycles without significant voltammetric changes. Collectively, our wearable glove-based sensor may be employed for analyses of chemical contaminants of concern, such as explosives (PA), drugs (DZ), and emerging pollutants (4-NP), helping in environmental and public safety control.

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The natural occurrence of 16 inorganic ions relevant to forensic explosives investigations on human hands was studied to support the evaluation of activity-level propositions when such traces are found on the hands or in the fingerprints of a suspect. A total of 594 hand swab extracts from 297 participants throughout Europe and the United States of America were analyzed using Ion Chromatography - Mass Spectrometry. The data provides a reference framework for future covert investigations and forensic casework. The results indicate that thiocyanate, chlorate, nitrite, lithium, strontium, and barium are rarely detected on the hands of individuals who have had no direct contact with explosives (P<0.03) and in quantities below 6 µg. Perchlorate contamination sporadically occurs without deliberately handling perchlorates (P=0.03), albeit at low levels (<12 µg). It also seems that the presence of perchlorate on hands is generally related to professions that involve explosives. Detecting substantial amounts of any of these rare ions on a suspect's hands would require a specific explanation. Because legitimate activities exist that can also result in elevated levels of ions of interest on hands, the context surrounding their presence has to be carefully assessed for each individual case.

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Canines are widely used for real-time detection of explosives and have proven to be on par with instrumental methods. Canines are thought to rely largely upon detection of volatile chemical constituents of the explosives, though not necessarily the explosive itself. Hence, it is crucial to understand the odor available to them as generated by training aids. Previous studies have established that the Training Aid Delivery Device (TADD) developed by SciK9 is a reliable training aid that reduces cross-contamination and doubles as a storage device. A TADD comprises a standardized container, a synthetic membrane, a membrane holder, and a lid. In the work presented, activated charcoal strips were placed above and below the TADD membrane to determine the relative amounts of volatiles emitted by dynamite (i.e., ethylene glycol dinitrate (EGDN) and trinitroglycerin (NG)). The strips were eluted and the extracts tested using gas chromatography-mass spectrometry in negative ion chemical ionization mode. A series of t-tests at 95% confidence level were performed to determine any differences in vapor composition above and below the membranes. Nine synthetic membranes and six glass fiber membranes were tested in this study. It was expected that the relative concentration of volatiles would remain the same on both sides of the membrane; however, selective removal of nitroglycerin by some membranes was observed. Synthetic membranes with larger pore sizes showed no alteration in the vapor composition. Both synthetic and glass fiber membranes did not show a significant change in relative concentration of the other volatile compound in dynamite, i.e., EGDN. Out of all the membranes tested, three synthetic membranes and four glass fiber membranes showed selective alteration in odor availability of nitroglycerin in dynamite. For training purposes, membranes that do not alter the vapor composition should be used in the training aid.

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A new smartphone-based chemiluminescence method has been introduced for the quantitative analysis of CL-20 (Hexanitroazaisowuertzitan) explosive. The solvent mixture, oxidizer agent, and concentration of the reactants were optimized using statistical procedures. CL-20 explosive showed a quenching effect on the chemiluminescence intensity of the luminol-NaClO reaction in the solvent mixture of DMSO/H2O. A smartphone was used as a detector to record the light intensity of chemiluminescence reaction as a video file. The recorded video file was converted to an analytical signal as intensity luminescence-time curve by a written code in MATLAB software. Dynamic range and limit of detection of the proposed method were obtained 2.0-240.0 and 1.1 mg⋅L-1, respectively, in optimized concentrations 1.5 × 10-3 mol⋅L-1 luminol and 1.0 × 10-2 mol⋅L-1 NaClO. Precursors TADB, HBIW, and TADNIW in CL-20 explosive synthesis did not show interference in measurement the CL-20 purity. The analysis of CL-20 spiked samples of soil and water indicated the satisfactory ability of the method in the analysis of real samples. The interaction of CL-20 molecules and OCl- ions is due to quench of chemiluminescence reaction of the luminol-NaClO.

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This report aims to examine the effects of impact velocity, impact depth, and impact orientation on the Cu-Ta weld joint of the explosive welding process via MD simulation. The findings indicate that the residual shear stress in the welded block mostly increases as the impact velocity rises. The bottom Ta block is more severely distorted than the higher Cu block due to the impact direction. During the tensile test, three stress zones can be identified including the low-stress Cu block, the high-stress Ta block, and the medium-stress weld joint in the middle of the samples. The weld joint position is lower than the median line of the welded block. The Cu-Ta welded block with 500 m/s impact velocities had the highest ultimate tensile strength (UTS) value of 6.49 GPa. With increasing impact depth, the atomic strain level, residual shear stress, and weld joint dimensions all noticeably increase. The Cu-Ta welded block with an impact depth of 7.5 Å has the greatest UTS values, measuring 11.65 GPa, because of its well-crystal structure. Changing the impact orientation does not result in a dramatic change in atomic strain. Orientation (001) vs (001) has the highest strain and stress rates. With an impact orientation of (110) vs. (111), the Cu-Ta welded block gets the highest UTS value of 8.03 GPa compared to other orientations.

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The explosive compound 2,4,6-trinitrotoluene (TNT) is well known as a major component of munitions. In addition to its potential carcinogenicity and mutagenicity in humans, recent reports have highlighted TNT toxicities in diverse organisms due to its occurrence in the environment. These toxic effects have been linked to the intracellular metabolism of TNT, which is generally characterised by redox cycling and the generation of noxious reactive molecules. The reactive intermediates formed, such as nitroso and hydroxylamine compounds, also interact with oxygen molecules and cellular components to cause macromolecular damage and oxidative stress. The current review aims to highlight the crucial role of TNT metabolism in mediating TNT toxicity, via increased generation of reactive oxygen species. Cellular proliferation of reactive species results in depletion of cellular antioxidant enzymes, DNA and protein adduct formation, and oxidative stress. While TNT toxicity is well known, its ability to induce oxidative stress, resulting from its reductive activation, suggests that some of its toxic effects may be caused by its reactive metabolites. Hence, further research on TNT metabolism is imperative to elucidate TNT-induced toxicities.

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There are many factors that may affect the longevity of or guide the use of canine training aids. Literature to date has mainly focused on identifying the headspace volatiles associated with training aids or odors and only minimal research exists into how different variables may alter those volatiles. The current study examines several factors affecting canine training aids: humidity, air flow, transportation, and operational deployment, using the triacetone triperoxide polymer odor capture-and-release canine training aid (TATP POCR) as the target. The TATP POCR is an absorption-based canine training aid developed to be used to safely train canines to detect the odor of the explosive TATP in operational settings. Comparisons of the TATP POCR to neat TATP are made throughout the manuscript. First, humidity increased the background components of the POCR matrix, as well as the amount of TATP recovered was above the POCR. Humidity thus affected the amount of TATP detected but did not prevent detection. Second, air flow lessened the lifetime of the TATP POCR. Third, the practice of using primary and secondary containment successfully prevented contamination, cross-contamination, and significant target loss, thereby maintaining kit integrity. Finally, the absorption of background odors from training environments was not observed. TATP headspace concentrations between a Deployed and Control POCR kit were not significantly different at time 0 (i.e., upon opening), which suggests that the operational use does not affect the function of the TATP POCR system. This information provides pivotal evidence for explosives detection canine handlers or trainers who utilize the TATP POCR.

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The effects of long-term ammunition pollution on microecological characteristics were analyzed to formulate microbial remediation strategies. Specifically, the response of enzyme systems, N/O stable isotopes, ion networks, and microbial community structure/function levels were analyzed in long-term (50 years) ammunition-contaminated water/sediments from a contamination site, and a compound bacterial agent capable of efficiently degrading trinitrotoluene (TNT) while tolerating many heavy metals was selected to remediate the ammunition-contaminated soil. The basic physical and chemical properties of the water/sediment (pH (up: 0.57-0.64), nitrate (up: 1.31-4.28 times), nitrite (up: 1.51-5.03 times), and ammonium (up: 7.06-70.93 times)) were changed significantly, and the significant differences in stable isotope ratios of N and O (nitrate nitrogen) confirmed the degradability of TNT by indigenous microorganisms exposed to long-term pollution. Heavy metals, such as Pb, Zn, Cu, Cd, Cs, and Sb, have synergistic toxic effects in ammunition-contaminated sites, and significantly decreased the microbial diversity and richness in the core pollution area. However, long-term exposure in the edge pollution area induced microorganisms to use TNT as a carbon and nitrogen sources for life activities and growth and development. The Bacteroidales microbial group was significantly inhibited by ammunition contamination, whereas microorganisms such as Proteobacteria, Acidobacteriota, and Comamonadaceae gradually adapted to this environmental stress by regulating their development and stress responses. Ammunition pollution significantly affected DNA replication and gene regulation in the microecological genetic networks and increased the risk to human health. Mg and K were significantly involved in the internal mechanism of microbial transport, enrichment, and metabolism of TNT. Nine strains of TNT-utilizing microbes were screened for efficient TNT degradation and tolerance to typical heavy metals (copper, zinc and lead) found in contaminated sites, and a compound bacterial agent prepared for effective repair of ammunition-contaminated soil significantly improved the soil ecological environment.

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In this work, the characteristics of the exothermic reaction between ammonium nitrate and sulfide ores were explored using COMSOL Multiphysics. This reaction can cause an increase in temperature within the blast holes of sulfide mines and can potentially induce premature explosions of the explosives. Initially, simulations were conducted to observe temperature variations in blast holes before and after the loading of explosives. Then, the impact of blast hole diameter and initial temperature on the thermal environment was assessed. Subsequent analysis focused on the fluid field's dynamics, examining flow rate changes and the concentration of signature gases produced by the reaction. Additionally, the influence of blast hole diameter on these parameters was evaluated. The results show that the blast hole temperature is positively related to its diameter and initial temperature. When the diameter of the blast hole is 120 mm and 165 mm, a significant change in flow rate is observed, with a trend of being rapidly increased and then rapidly decreased. The production of NH3 is always found to be greater than that of the other two gases. As for NO and SO2, their production is characterized by an approximate ratio of 1:2. The numerical simulation results can provide important theoretical guidance for the spontaneous detonation of blast hole in sulfide mines.

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Sensitive, accurate, and reliable detection of explosives has become one of the major needs for international security and environmental protection. Colloidal quantum dots, because of their unique chemical, optical, and electrical properties, as well as easy synthesis route and functionalization, have demonstrated high potential to meet the requirements for the development of suitable sensors, boosting the research in the field of explosive detection. Here, we critically review the most relevant research works, highlighting three different mechanisms for explosive detection based on colloidal quantum dots, namely photoluminescence, electrochemical, and chemoresistive sensing. We provide a comprehensive overview and an extensive discussion and comparison in terms of the most relevant sensor parameters. We highlight advantages, limitations, and challenges of quantum dot-based explosive sensors and outline future research directions for the advancement of knowledge in this surging research field.

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