Search Results (87)

Aviation security increasingly relies on explosive trace detectors (ETDs), particularly those employing ion mobility spectrometry (IMS). However, few studies have systematically compared the performance of IMS-based ETDs, especially in terms of measurement uncertainty and stability under repeated operation. This study evaluated two commercially available IMS-based ETDs using statistical analysis and data visualization. Repeated TNT (2,4,6-trinitrotoluene) detection tests were conducted to assess performance over consecutive operations. The results revealed significant differences in measurement uncertainty between the two devices. One ETD exhibited stable measurements throughout, while the other showed variance fluctuations that stabilized only after extended use. Despite using the same detection principle, the two devices responded differently to operational conditions, suggesting that internal specifications and design choices significantly affect reliability. This study offers a methodological framework for ETD comparison and provides insights to support more rigorous evaluation and certification practices in aviation security. Full article

The substituent effects on crystal stacking topology and stability of the 5,5-dinitro-2H,2H-3,3-bi-1,2,4-triazole (DNBT) and its three energetic cocrystals with 1,3,5-trinitrobenzene (TNB), 2,4,6-trinitrotoluene (TNT), and picric acid (PA) were systematically investigated through combined density functional theory (DFT) calculations and classical molecular dynamics (MD) simulations. The interaction mechanism and detonation performance of the three energetic cocrystals were implemented to the electrostatic potential (ESP), Hirshfeld surface analysis, radial distribution function (RDF), binding energy, and detonation parameters. In contrast to N-H⋯O interactions in DNBT, three cocrystals exhibited more distinctly weak C-H⋯O intermolecular hydrogen bonds and NO₂-π stacking interactions to stabilize the lattice. Notably, the highest binding energy of PA/DNBT shows the largest stability and lowest impact sensitivity is related to the more intermolecular interactions. Although the introduction of substituents slightly affects the crystal density of DNBT crystals, it significantly reduces the impact sensitivity. Moreover, the balanced detonation performance and impact sensitivity of DNBT-based cocrystals make it a candidate to expand the applications of DNBT crystals. These findings contribute to a broadened understanding of construction and design strategies for the energy release mechanisms of energetic compounds with the azoles ring family. Full article

Maritime safety is crucial as vessels underpin global trade, but engine room explosions threaten crew safety, the environment, and assets. With modern ship designs growing more complex, numerical simulation has become vital for analyzing and preventing such events. This study examines safety risks from alternative fuel explosions in ship engine rooms, using the Trinitrotoluene (TNT)-equivalent method. A finite element model of a double-layer cabin explosion is developed, and simulations using blastFOAM in OpenFOAM v9 analyze shock wave propagation and stress distribution. Four explosion locations and five scales were tested, revealing that explosion scale is the most influential factor on shock wave intensity and structural stress, followed by equipment layout, with location having the least—though still notable—impact. Near the control room, an initial explosion caused a peak overpressure of 2.4 × 10⁶ Pa. Increasing the charge mass from 10 kg to 50 kg raised overpressure to 3.9 × 10⁶ Pa, showing strong dependence of blast intensity on explosive mass. Equipment absorbs and reflects shock waves, amplifying localized stresses. The findings aid in optimizing engine room layouts and improving explosion resistance, particularly for alternative fuels like liquefied natural gas (LNG), enhancing maritime safety and sustainability. Full article

The extensive use of nitro compounds in agriculture, industry, armaments, and pharmaceuticals, along with their toxic effects on living organisms, necessitates efficient and environmentally sustainable analytical methods. Traditional extraction techniques often involve practices that are not eco-friendly, such as the use of large volumes of solvents, toxic chemicals, and the generation of significant waste; therefore, the single-drop microextraction technique was involved in overcoming these limitations. This study shows an environmentally friendly method for nitro compound analysis focusing on NB (Nitrobenzene), 2-NT (2-Nitrotoluene), 3-NT (3-Nitrotoluene), 4-NT (4-Nitrotoluene), 1,3-DNB (1,3-Dinitrobenzene), 1,2-DNB (1,2-Dinitrobenzene), 2,4-DNT (2,4-Dinitrotoluene), and TNT (Trinitrotoluene). To separate and to detect selected nitro compounds, gas chromatography with an electron capture detector was utilized, which is highly selective for analytes containing nitro groups. To determine optimal experimental conditions, extraction parameters were studied, including the impact of salt addition, temperature, and pH on extraction efficiency. Key performance parameters, such as limit of detection (LOD), limit of quantification (LOQ), repeatability, extraction recoveries, calibration range, and matrix effects, were assessed. The LOD values ranged from 0.01 to 0.09 μg/L in deionized water, 0.01 to 0.06 μg/L in tap water, 0.01 to 0.03 μg/L in seawater, and 0.03 to 0.11 μg/L in model forensic rinse water. The optimized method was successfully applied to the determination of nitro compounds in real environmental water samples and forensic rinse water samples. The environmental sustainability and greenness of the proposed method was evaluated with the AGREE, AGREEprep, and AESA techniques. Full article

A new hyphenated technique using thin-layer chromatography (TLC) to separate analytes in mixtures, coupled with mid-infrared (MIR) laser spectroscopy for identification and quantification, is presented. The method, which provides a means for rapid screening of analytes that is practical, low-cost, fast, robust, and reproducible, was tested using nitroaromatic and aliphatic nitro high explosives (HEs) as target analytes. HEs are anthropogenic contaminants containing an -NO₂ group. For validation of the new technique, a direct comparison of the 2,4,6-trinitrotoluene (TNT) spectrum, obtained by attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy coupled with TLC, was carried out. The MIR laser spectroscopy-based method was evaluated by calculating the analytical figures of merit regarding the calibration curves’ linearity and the method’s sensitivity and precision. The TNT spectrum obtained by the MIR laser method showed two prominent and characteristic bands of the explosive at approximately 1350 cm⁻¹ and 1550 cm⁻¹ compared to the spectrum acquired by ATR-FTIR. The detection limit calculated for TNT was 84 ng, while the quantification limit was 252 ng. Multivariate analysis was used to evaluate the spectroscopic data to identify sources of variation and determine their relation. Partial least squares (PLS) regression analysis and PLS combined with discriminant analysis (PLS-DA) were used for quantification and classification. The new technique, TLC-QCL, is amenable to a smaller footprint with further developments in MIR laser technology, making it portable for fieldwork. Full article

A glycoluril-derived molecular-clip-based supramolecular organic framework (clip-SOF) with intrinsic porosity was prepared. The clip-SOF was used for the adsorption and removal of 2,4,6-trinitrotoluene (TNT) driven by noncovalent interactions. The efficiency of TNT removal by clip-SOFs is up to 88.5% in adsorption equilibrium, and the TNT adsorption capacity of clip-SOFs is about 40.2 mg/g at 25.0 °C. Clip-SOFs have good reusability, exhibiting almost no loss in performance in ten consecutive recycling tests. This work not only provides a new method for adsorbing energetic materials, but also promotes the application of supramolecular hosts in crystal engineering. Full article

A highly efficient and sensitive ion mobility spectrometry (IMS) system with laser desorption sampling was applied for rapid explosive detection using different surface materials. This portable IMS detector, powered by a battery, offers mobility and is suitable for use in the field or combat zones. The laser desorption (LD) sampling of common explosives (Trinitrotoluene—TNT; Dinitrotoluenes—DNTs; Hexogene—RDX; pentaerythritol tetranitrate—PETN; plastic explosives—Compound 4 (C-4) and Semtex) on a wide range of common surface materials, such as metal, ceramic, plastic, glass, drywall, paper, wood, and textiles, was studied. Successful detection was achieved on nearly all surfaces except flammable materials (paper, wood, and textiles). The limit of detection (LOD) was determined for each explosive and specific surface, demonstrating an impressive LOD of 7 ng/mm² for TNT. RDX, C-4, PETN, and Semtex achieved LOD values of 15 ng/mm², while DNTs showed an LOD of approximately 50 ng/mm². Full article

Endocrine-disrupting chemicals (EDCs) impair growth and development. While EDCs can occur naturally in aquatic ecosystems, they are continuously introduced through anthropogenic activities such as industrial effluents, pharmaceutical production, wastewater, and mining. To elucidate the chronic toxicological effects of endocrine-disrupting chemicals (EDCs) on aquatic organisms, we collected experimental data from a standardized chronic exposure test using Daphnia magna (D. magna), individuals of which were exposed to a potential EDC, trinitrotoluene (TNT). The chronic toxicity effects of this compound were explored through differential gene expression, gene ontology, network construction, and putative adverse outcome pathway (AOP) proposition. Our findings suggest that TNT has detrimental effects on the upstream signaling of Tcf/Lef, potentially adversely impacting oocyte maturation and early development. This study employs diverse bioinformatics approaches to elucidate the gene-level toxicological effects of chronic TNT exposure on aquatic ecosystems. The results provide valuable insights into the molecular mechanisms of the adverse impacts of TNT through network construction and putative AOP proposition. Full article

This paper presents the results of an experimental study of the dynamic characteristics of the process of laser fragmentation/laser-induced fluorescence (LF/LIF) of trinitrotoluene traces on a paper surface under synchronized double-pulse laser irradiation. An Nd:YAG-laser (266 nm) was used for the fragmentation of TNT molecules, while fluorescence excitation of their NO fragments was performed using a KrF laser with a generation line of 247.867 nm in the region of the location of the bandhead of the P₁₂ branch of the γ(0, 2) absorption band of the NO molecule. It was shown that the dissociation process of TNT traces has an inertial character and continues after the cessation of the fragmenting laser pulse. It was found that with the delay values between the fragmenting and probing laser pulses in the region of 200 ns, the efficiency of the LF/LIF method can be increased by 12 times. This paper presents the results of an experimental evaluation of the efficiency of two-pulse LF/LIF compared to single-pulse laser exposure, where the fragmentation of TNT molecules and excitation of their NO fragments were simultaneously performed by KrF laser pulses. The possibility of multiple increases in the efficiency of two-pulse LF/LIF with an increase in the energy density of the fragmenting laser radiation was shown. The obtained results are important in terms of increasing the sensitivity and/or range of the LF/LIF method for remote detection of traces of nitrocompounds. Full article

Blasting is a key process that plays a significant role in various industries, including mining and construction. To measure the effectiveness and potential impact of a blast generated by different explosives, industry professionals use a widely accepted parameter known as TNT (trinitrotoluene) equivalent. This manuscript provides an overview of the approach based on the application of the explosive equivalency principle in the prediction of the seismic effects caused by the detonation of different explosives. The explosive equivalents of studied explosives are derived from the results of thermochemical calculations using the EXPLO5 code and compared to field tests. The results have demonstrated that the equivalency approach can potentially be a useful tool in the assessment of blast-induced seismic effects. Full article

Canine olfaction is a highly developed sense and is utilized for the benefit of detection applications, ranging from medical diagnostics to homeland security and defense prevention strategies. Instrumental validation of odor delivery methods is key to standardize canine olfaction research to establish baseline data for explosive detection applications. Solid-phase microextraction gas chromatography (SPME/GC-MS) was used to validate the odor delivery of an olfactometer. Three explosive classes were used in this study: composition C-4 (C-4), trinitrotoluene (TNT), and ammonium nitrate (AN). Dynamic airflow sampling yielded the successful detection of previously reported target volatile organic compounds (VOCs): 2,3-dimethyl-2,3-dinitrobutane (DMNB) in C-4 and 2-ethylhexan-1-ol (2E1H) in ammonium nitrate and TNT across odor dilutions of 80%, 50%, 25%, 12%, and 3%. C-4 highlighted the most reliable detection from the olfactometer device, depicting a response decrease as a function of dilution factor of its key odor volatile DMNB across the entire range tested. TNT only portrayed 2-ethylhexan-1-ol as a detected odor volatile with a detection response as a function of dilution from 80% down to 12%. Comparatively, ammonium nitrate also depicted 2-ethylhexan-1-ol as an odor volatile in the dynamic airflow sampling but with detection only within the upper scale of the dilution range (80% and 50%). The results suggest the importance of monitoring odor delivery across different dilution ranges to provide quality control for explosive odor detection using dynamic airflow systems. Full article

Soil pollution by TNT(2,4,6-trinitrotoluene), RDX(hexahydro-1,3,5-trinitro-1,3,5-triazacyclohexane), and HMX(octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine), resulting from the use of explosives, poses significant challenges, leading to adverse effects such as toxicity and alteration of microbial communities. Consequently, there is a growing need for effective bioremediation strategies to mitigate this damage. This review focuses on Microbial and Bio-omics perspectives within the realm of soil pollution caused by explosive compounds. A comprehensive analysis was conducted, reviewing 79 articles meeting bibliometric criteria from the Web of Science and Scopus databases from 2013 to 2023. Additionally, relevant patents were scrutinized to establish a comprehensive research database. The synthesis of these findings serves as a critical resource, enhancing our understanding of challenges such as toxicity, soil alterations, and microbial stress, as well as exploring bio-omics techniques like metagenomics, transcriptomics, and proteomics in the context of environmental remediation. The review underscores the importance of exploring various remediation approaches, including mycorrhiza remediation, phytoremediation, bioaugmentation, and biostimulation. Moreover, an examination of patented technologies reveals refined and efficient processes that integrate microorganisms and environmental engineering. Notably, China and the United States are pioneers in this field, based on previous successful bioremediation endeavors. This review underscores research’s vital role in soil pollution via innovative, sustainable bioremediation for explosives. Full article

This study offers an updated overview of the soil and water remediation strategies employed to address the widespread environmental and public health risks associated with explosive compounds, particularly TNT and RDX. Recognizing soil contamination originating from military activities, industrial accidents, and historical land use, this review delves into physical, chemical, and biological approaches to mitigating ecological and human health concerns. While physical methods like excavation and disposal are effective, their applicability is constrained by cost and logistical challenges for large contaminated areas. Chemical methods, such as oxidation and reduction, focus on transforming explosives into less toxic byproducts. Biological remediation utilizing plants and microorganisms emerges as a cost-effective and sustainable alternative. This review highlights challenges, including the persistence of explosive compounds, potential groundwater leaching, and the necessity for long-term monitoring. Emphasizing the need for site-specific strategies, considering the contaminant type, concentration, soil properties, and regulatory requirements, this study advocates for integrated and sustainable remediation approaches in pilot-scale applications. It concludes by evaluating the appropriate solution based on the advantages and disadvantages of the categories of soil and groundwater remediation methods. The duration, the effectiveness, and the cost of available technologies were estimated. Full article

The transport of mobile colloidal particles with organic pollutants in porous media has attracted considerable attention. Aniline and 2,4,6-trinitrotoluene (TNT), as aromatic compounds and key components of energetic materials, are continuously released into the environment. This study compared the co-transport of loess colloidal particles with aniline and TNT, aiming to investigate the influence of structural and physicochemical properties of the pollutants. The colloids were prepared and characterized, and static adsorption and dynamic column experiments were conducted. The results indicate that the adsorption processes of aniline and TNT both conformed to the quasi-second-order kinetic and the intra-particle diffusion models, with aniline exhibiting higher rate constants than TNT. The main adsorption mechanism involved van der Waals force, hydrogen bonding, and electrostatic interaction. Response surface experiments indicated that the adsorption capacity increased with higher initial concentration of organic compound but decreased with larger particle size and higher Na⁺ concentration. In column experiments, the adsorption of loess colloid particles on aniline and TNT was strongly correlated with the concentration of loess colloid particles. Loess colloid particles could be used as carriers to enhance the co-transport, with aniline exhibiting a faster transport rate due to the differences in polarity and molecular structure compared to TNT. In summary, loess colloidal particles enhanced the transport behavior of aniline and TNT in saturated loess columns. The differences in polarity and molecular structure of aniline and TNT further affect their co-transport mechanism in loess. Full article

Amid the ongoing global warming crisis, there has been growing interest in hydrogen energy as an environmentally friendly energy source to achieve carbon neutrality. A stable and large-scale hydrogen storage infrastructure is essential to satisfy the increasing demand for hydrogen energy. Particularly for hydrogen refueling stations located in urban areas, technological solutions are required to ensure the stability of adjacent civil structures in the event of hydrogen storage tank explosions. In this study, a numerical analysis using equivalent trinitrotoluene (TNT) and Concrete Damage Plasticity (CDP) models was employed to analyze the dynamic behavior of the ground in response to hydrogen gas explosions in shallow underground hydrogen storage facilities and to assess the stability of nearby structures against explosion effects. According to the simulation results, it was possible to ensure the structural stability of nearby buildings and tunnel structures by maintaining a minimum separation distance. In the case of nearby building structures, a distance of at least 6 to 7 m is needed to be maintained from the underground hydrogen storage facility to prevent explosion damage from a hydrogen gas explosion. For nearby tunnel structures, a distance of at least 10 m is required to ensure structural stability. Full article