Trinitrotoluene Research Articles

Behavior of Barrier Wall under Hydrogen Storage Tank Explosion with Simulation and TNT Equivalent Weight Method

Hydrogen gas storage place has been increasing daily because of its consumption. Hydrogen gas is a dream fuel of the future with many social, economic and environmental benefits to its credit. However, many hydrogen storage tanks exploded accidentally and significantly lost the economy, infrastructure, and living beings. In this study, a protection wall under a worst-case scenario explosion of a hydrogen gas tank was analyzed with commercial software LS-DYNA. TNT equivalent method was used to calculate the weight of TNT for Hydrogen. Reinforced concrete and composite protection wall under TNT explosion was analyzed with a different distance of TNT. The initial dimension of the reinforced concrete protection wall was taken from the Korea gas safety code book (KGS FP217) and studied the various condition. H-beam was used to make the composite protection wall. Arbitrary-Lagrangian-Eulerian (ALE) simulation from LS-DYNA and ConWep pressure had a good agreement. Used of the composite structure had a minimum displacement than a normal reinforced concrete protection wall. During the worst-case scenario explosion of a hydrogen gas 300 kg storage tank, the minimum distance between the hydrogen gas tank storage and protection wall should be 3.6 m.

The characteristics and metabolic potentials of the soil bacterial community of two typical military demolition ranges in China

The response mechanism of soil microbiota in military polluted sites can effectively indicate the biotoxicity of ammunition. In this study, two military demolition ranges polluted soils of grenades and bullet were collected. According to high-throughput sequencing, after grenade explosion, the dominant bacteria in Site 1 (S1) are Proteobacteria (97.29 %) and Actinobacteria (1.05 %). The dominant bacterium in Site 2 (S2) is Proteobacteria (32.95 %), followed by Actinobacteria (31.17 %). After the military exercise, the soil bacterial diversity index declined significantly, and the bacterial communities interacted more closely. The indigenous bacteria in S1 were influenced more compared to those in S2. According to the environmental factor analysis, the bacteria composition can easily be influenced by heavy metals and organic pollutants, including Cu, Pb, Cr and Trinitrotoluene (TNT). About 269 metabolic pathways annotated in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database were detected in bacterial communities, including nutrition metabolism (C, 4.09 %; N, 1.14 %; S, 0.82 %), external pollutant metabolism (2.52 %) and heavy metal detoxication (2.12 %), respectively. The explosion of ammunition changes the basic metabolism of indigenous bacteria, and heavy metal stress inhibits the TNT degradation ability of bacterial communities. The pollution degree and community structure influence the metal detoxication strategy at the contaminated sites together. Heavy metal ions in S1 are mainly discharged through membrane transporters, while heavy metal ions in S2 are mainly degraded through lipid metabolism and biosynthesis of secondary metabolites. The results obtained in this study can provide deep insight into the response mechanism of the soil bacterial community in military demolition ranges with composite pollutions of heavy metals and organic substances. CapsuleHeavy metal stress changed the composition, interaction and metabolism of indigenous communities in military demolition ranges, especially the TNT degradation process.

Plasmonic Coupling of Au Nanoclusters on a Flexible MXene/Graphene Oxide Fiber for Ultrasensitive SERS Sensing.

High sensitivity, good signal repeatability, and facile fabrication of flexible surface enhanced Raman scattering (SERS) substrates are common pursuits of researchers for the detection of probe molecules in a complex environment. However, fragile adhesion between the noble-metal nanoparticles and substrate material, low selectivity, and complex fabrication process on a large scale limit SERS technology for wide-ranging applications. Herein, we propose a scalable and cost-effective strategy to a fabricate sensitive and mechanically stable flexible Ti3C2Tx MXene@graphene oxide/Au nanoclusters (MG/AuNCs) fiber SERS substrate from wet spinning and subsequent in situ reduction processes. The use of MG fiber provides good flexibility (114 MPa) and charge transfer enhancement (chemical mechanism, CM) for a SERS sensor and allows further in situ growth of AuNCs on its surface to build highly sensitive hot spots (electromagnetic mechanism, EM), promoting the durability and SERS performance of the substrate in complex environments. Therefore, the formed flexible MG/AuNCs-1 fiber exhibits a low detection limit of 1 × 10-11 M with a 2.01 × 109 enhancement factor (EFexp), signal repeatability (RSD = 9.80%), and time retention (remains 75% after 90 days of storage) for R6G molecules. Furthermore, the l-cysteine-modified MG/AuNCs-1 fiber realized the trace and selective detection of trinitrotoluene (TNT) molecules (0.1 μM) via Meisenheimer complex formation, even by sampling the TNT molecules at a fingerprint or sample bag. These findings fill the gap in the large-scale fabrication of high-performance 2D materials/precious-metal particle composite SERS substrates, with the expectation of pushing flexible SERS sensors toward wider applications.

Mechanistic elucidation of shock response of bis(1,2,4-oxadiazole)bis(methylene) dinitrate (BOM): A ReaxFF molecular dynamics investigation

The use of trinitrotoluene (TNT) in industrial processes or military operations presents a significant threat to both the environment and human health due to its toxicity. Recently, it has been discovered that bis(1,2,4-oxadiazole)bis(methylene) dinitrate (BOM) can be an appropriate substitute of TNT due to its low sensitivity, high detonation velocity, and nearly insignificant impact on the surrounding environment. In this study, we utilize molecular dynamics (MD) simulations with a ReaxFF force field to investigate the thermomechanical and chemical response of BOM to shock loading. We simulate shocks using the Hugoniostat technique and observe shock-induced, volume-expanding exothermic reactions following a short induction time for strong enough insults. We analyze the shock behavior at various pressures to determine the conditions necessary to initiate detonation and evaluate the consequent events of detonation. A transition between unreacted and reacted materials has been observed and several detonation properties, such as detonation pressure and velocity, have been calculated at the Chapman–Jouguet state. We elucidate the reaction initiation pathways by predicting the intermediates and final products of the exothermic reaction. The quantity of intermediates and products has been studied for different applied shock loadings to understand the effect of loadings on chemical reactions. This study illustrates how reactive MD simulations can be used to characterize the physics and chemistry of high-energy materials subjected to shock loading, and we believe that our research can assist to shed light on numerous features of BOM that may establish it as a viable alternative to TNT.

О параметрах пульсации газового пузыря при подводном взрыве в свободной воде

Object and purpose of research. This paper discusses underwater explosion. The purpose of the study was to justify the mathematical model enabling the assessment of gas bubble pulses of underwater explosion for a wide range of explosion depths and charge weights. Subject matter and methods. The paper discusses an explosion in open-water conditions. The study relies on analytical materials, numerical solution of common differential equations and on the experimental data. Main results. The study describes calculation expressions for gas bubble pulse parameters available in literature. It also compares calculation results with the experimental data for TNT explosions. Conclusion. As compared to existing solutions and empirical expressions, the mathematical model suggested in this paper enables the assessment of pulse parameters for a wide range of explosion depths and charge weights. Calculation results obtained as per this model correlate with available test data. The results of this work may be used to estimate underwater explosion impact upon marine objects and structures.

Mechanical Behavior and Damage Evolution of a Fabricated Rectangular Tunnel with a Mortise-and-Tenon Joint under Internal Explosion

A new mortise-and-tenon joint for a fabricated rectangular tunnel is designed in this study. To explore the damage evolution of a fabricated rectangular tunnel with a mortise-and-tenon joint under internal explosion, a refined numerical model is established by using Abaqus finite element software. The sensitivity of the explosion resistance of a rectangular tunnel to different trinitrotoluene (TNT) equivalents, concrete strength grades, scaled distances, and types of joints is analyzed. The spatiotemporal effect and damage characteristics of the fabricated rectangular tunnel after a central explosion are discussed. Finally, the deformation characteristics of the tunnel corner are quantified by defining a tunnel deformation angle. The results show that the tunnel is more sensitive to the explosion equivalent and less sensitive to the concrete strength grade, and the tunnel roof is highly sensitive to TNT at different distances. The damage of the fabricated rectangular tunnel under an explosion wave has significant spatiotemporal evolution characteristics. The roof and floor of the tunnel are first impacted by explosion, and their reflection on the explosion wave will significantly enhance the explosion effect. The joint of the prefabricated tunnel has small stiffness and large flexibility, and the reflection enhancement effect on the shock wave is weak. The impact of explosive waves results in tensile stresses on the outside of the roof and floor of the tunnel and on the connection of the midpartition, where the explosion resistance is weak. The tunnel deformation angle is used to quantify the deformation damage characteristics of the tunnel. The results show that the safety height of the vehicle in the tunnel should be controlled within 3.8 m. The current research provides some valuable information for the future antiexplosion design and evaluation of the prefabricated frame tunnel.

Control of Explosive Chemical Reactions by Optical Excitations: Defect-Induced Decomposition of Trinitrotoluene at Metal Oxide Surfaces.

Interfaces formed by high energy density materials and metal oxides present intriguing new opportunities for a large set of novel applications that depend on the control of the energy release and initiation of explosive chemical reactions. We studied the role of structural defects at a MgO surface in the modification of electronic and optical properties of the energetic material TNT (2-methyl-1,3,5-trinitrobenzene, also known as trinitrotoluene, C7H5N3O6) deposited at the surface. Using density functional theory (DFT)-based solid-state periodic calculations with hybrid density functionals, we show how the control of chemical explosive reactions can be achieved by tuning the electronic structure of energetic compound at an interface with oxides. The presence of defects at the oxide surface, such as steps, kinks, corners, and oxygen vacancies, significantly affects interfacial properties and modifies electronic spectra and charge transfer dynamics between the oxide surface and adsorbed energetic material. As a result, the electronic and optical properties of trinitrotoluene, mixed with an inorganic material (thus forming a composite), can be manipulated with high precision by interactions between TNT and the inorganic material at composite interfaces, namely, by charge transfer and band alignment. Also, the electron charge transfer between TNT and MgO surface reduces the decomposition barriers of the energetic material. In particular, it is shown that surface structural defects are critically important in the photodecomposition processes. These results open new possibilities for the rather precise control over the decomposition initiation mechanisms in energetic materials by optical excitations.

Parametric Effects on the Mixing Efficiency of Resonant Acoustic Mixing Technology for High-Viscosity Mixture: A Numerical Study

Numerical investigations were conducted on the mixing efficiency of resonant acoustic mixing (RAM) technology using a high-viscosity mixture under vertically forced vibrations. The density distribution was analyzed for a mixture of high-melting explosive (HMX) and trinitrotoluene (TNT). The effects of mixing time, amplitude, frequency, fill level, and mixing vessel geometry were evaluated to determine their influence on the blend homogeneity and the efficiency of the mixing process. The results showed that amplitude and frequency both have significant influences on the mixing efficiency of the RAM process. With higher values of amplitude and frequency, the mixing efficiency was very good, and uniform mixing was achieved in a much shorter time. At the same time, it was seen that geometric changes did not affect the mixing process; in contrast, varying the fill level did have a significant effect. This approach could potentially be used for pharmaceutical blending, cosmetics, and explosive applications, where only small quantities of active particle ingredients (APIs) can change the behavior of the mixture.

Controlling the sensitivity and selectivity for the detection of nitro-based explosives by modulating the electronic substituents on the ligand of AIPE-active cyclometalated iridium(III) complexes.

Nitroaromatic compounds are extremely explosive materials that pose a national security risk and raise environmental concerns. The design and development of sensitive and selective compounds for explosive materials are highly desirable. 'Aggregation-Induced Emission' (AIE) active materials are best suited for sensing purposes because of their sensitivity, fast detection time, and easy operation. By rationally incorporating substituents on the cyclometalated (C^N) ligand, four different AIE active iridium(III) based monocyclometalated complexes with the general formula [Ir(PPh3)2(H)(Cl)(C^N)] were synthesized. The phenyl ring of the phenyl pyridine cyclometalated portion of an iridium(III) complex was substituted with the right substituents to adjust the FMO levels thus, leading to appropriate alignment of the energy levels. Each of the resulting complexes displayed a significant property known as 'Aggregation-Induced Phosphorescent Emission' (AIPE). The complexes were subjected to structural characterization, electrochemical analysis, and photophysical property studies. The synthesized complexes were employed for the detection of aromatic nitro explosive compounds such as trinitrophenol (TNP) and trinitrotoluene (TNT) in the aqueous phase with a high degree of sensitivity. The sensing capabilities of each complex were assessed for these nitro explosive compounds and compared to those of the unsubstituted iridium(III) complex (M). Notably, the best limits of detection for TNP and TNT have been achieved with iridium(III) complexes [M1 (489 pM) and M3 (3.6 nM)] within the literature reported until now. For detecting picric acid with M1, FRET was found to be the potential mechanism, and for TNT, PET was found to be the cause of emission quenching by M3. Furthermore, for low-cost detection, filter paper-based sensing was also found effective for each complex. Real-field sensing of PA in soil samples was also performed.

Molecular Dynamics Simulation of Shock Response of CL-20 Co-crystals Containing Void Defects

To investigate the effect of void defects on the shock response of hexanitrohexaazaisowurtzitane (CL-20) co-crystals, shock responses of CL-20 co-crystals with energetic materials ligands trinitrotoluene (TNT), 1,3-dinitrobenzene (DNB), solvents ligands dimethyl carbonate (DMC) and gamma-butyrolactone (GBL) with void were simulated, using molecular dynamics method and reactive force field. It is found that the CL-20 co-crystals with void defects will form hot spots when impacted, significantly affecting the decomposition of molecules around the void. The degree of molecular fragmentation is relatively low under the reflection velocity of 2 km/s, and the main reactions are the formation of dimer and the shedding of nitro groups. The existence of voids reduces the safety of CL-20 co-crystals, which induced the sensitivity of energetic co-crystals CL-20/TNT and CL-20/DNB to increase more significantly. Detonation has occurred under the reflection velocity of 4 km/s, energetic co-crystals are easier to polymerize than solvent co-crystals, and are not obviously affected by voids. The results show that the energy of the wave decreases after sweeping over the void, which reduces the chemical reaction frequency downstream of the void and affects the detonation performance, especially the solvent co-crystals.

Application of steel fiber concrete in small box girder under vehicle explosion load

In recent years, the exceptional performance of steel fiber-reinforced concrete in blast and impact resistance has garnered widespread recognition, sparking considerable interest in its practical application in small box girders. To this end, nine groups of Trinitrotoluene (TNT) explosion simulation experiments were designed with the equivalent magnitudes matching those of actual automobile explosions to evaluate the anti-explosion and anti-penetration capabilities of steel fiber-reinforced concrete and ordinary concrete using the Arbitrary Lagrangian-Eulerian (ALE) method and the Smoothed Particle Hydrodynamics-ALE method. The aim was to explore the application prospects of steel fiber-reinforced concrete in small box girders. The research results demonstrate that with increasing TNT equivalent, the leading cause of breach to concrete slabs changes from spalling to cratering. The penetration resistance of steel fiber-reinforced concrete slabs is superior to its blast resistance. However, when the explosive force is larger than the sedan, the anti-explosion effect of steel fiber-reinforced concrete slabs becomes negligible. Moreover, under typical automobile explosion loads, the addition of 2% steel fibers can reduce spalling by up to 23% and cratering by up to 13% and can decrease the area of penetration damage by up to 47%. In designing blast-resistant structures, steel fiber-reinforced concrete is not recommended to enhance the blast resistance of bridges when the TNT equivalent exceeds 500 kg.

A novel design of blast proof sandwich structure with hybrid skin

In the present modern age, explosive terrorist attacks are increasing day by day. Explosive attacks can take place anytime and anywhere. This is a hazard to both people and property. Hence, blast-proof structures are in demand for the current era to protect humans and properties. An effort has been made to design a novel blast-proof sandwich to fulfil this requirement. A sandwich structure made of steel was designed using a square honeycomb core (Model-1). The blast resistance analysis of the designed honeycomb sandwich structures was performed on ABAQUS/Explicit. The modelled sandwiches were subjected to conventional weapons effects program (CONWEP) air-blast loads ranging from 1 kg to 3 kg trinitrotoluene (TNT) for a fixed stand-off distance (SoD) of 150 mm. After the mesh convergence study and validation of the Model-1 with experimental results available in the literature, the 5 mm steel front skin was replaced by 1.5 mm steel/2 mm carbon fibre reinforced polymer (CFRP)/1.5 mm steel hybrid skin for Model-2 to reduce the weight of the structure with improved blast performance. In Model-3, both the 5 mm steel front skin and the 5 mm steel back skin were replaced by 1.5 mm steel/2 mm CFRP/1.5 mm steel hybrid skins for a further reduction in the weight of the structure. The blast resistance of sandwich configurations was evaluated in terms of the protective back skin deflection during blast loads. The use of hybrid skins in a sandwich structure drastically improves blast resistance in terms of smaller skin deflection. The square honeycomb core used sandwich with the hybrid front skin (Model-2) has the best blast proof characteristics and is recommended for armoured vehicles and skid plates of automobiles to protect the lives of humans.

Numerical analysis of honeycomb sandwich panels under blast load

When subjected to severe loadings, critical military and civilian structures must be able to withstand and maintain their functionality (e.g., impact, blast, thermal shock, etc). Sandwich panels with a low-density core have showed immense potential for devising shock-resistant structures in this context. Due to their excellent energy absorption, lightweight, and high specific stiffness, sandwich constructions with a light core have gained popularity. They are used mainly in aircraft and defence applications. Hence, understanding the behaviour of blast loaded sandwich structures is essential for the successful protection of human life and property. However, conducting an experimental analysis is a costly and time-consuming exercise with an additional risk to human safety. Therefore, numerical analysis is a much better alternative. In this research work, finite element (FE) analysis software ABAQUS/CAE has been used to study the behaviour of metallic honeycomb sandwich panels with squared, hexagonal and circular cores when subjected to blast loads of different kilograms of trinitrotoluene (TNT). The results of the FE modelling for square-core honeycomb sandwich panels were validated by comparing them to existing experimental data available in the literature. The effect of aluminium foam on front face deflection and energy absorption was also investigated. It was found that panels with circular core gave the best results as compared to hexagonal and square cores. After addition of foam, it was observed that the front plate deflection reduced for all core types. Also, a relation was observed between the order of deformation and plastic energy dissipation.

Boosting Laser-Ignited Combustion Performance of Energetic Materials with Low Sensitivity: Integration of Triazene-Bridged Triazole with Oxygen-Rich Moieties via Noncovalent Self-Assembly

It has long been a driving force in the development of energetic materials to hunt for novel high-energy density materials (HEDMs) with high energy and good stability. Recently, the noncovalent self-assembly strategy of energetic anions and cations to generate HEDMs is an effective strategy for introducing an oxidizer and fuel separately into the energy system. In this study, bis(1,2,4-triazolyl)triazene containing triazene (−N═N═NH−) and oxidant molecules (i.e., HNO3 and HClO4) were selected as high-energy ions to develop new high energy materials by using noncovalent self-assembly. The experimental results showed that three exemplary compounds possess excellent detonation pressure and detonation velocity (PC–J: 22.8–29.3 GPa and D: 7425–8135 m s–1), which are comparable to the classical explosive trinitrotoluene (TNT) (PC–J: 19.5 GPa and D: 6881 m s–1) as well as 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) (PC–J: 34.9 GPa and D: 8795 m s–1). Moreover, 1 and 3 exhibit low mechanical sensitivities (IS: 40 J and IS: 70 J). Thus, 1 and 3 have great potential as insensitive energetic materials. Especially, these energetic assemblies have excellent laser-ignited combustion properties and can be used as candidates for low sensitivity propellants.

Blast Resistance Capacity of Seismically Designed Building Frames

Because of the inherent uncertainty in the blast loading caused due to terrorist attacks, most buildings are not designed for blast loading, but they are routinely designed for earthquake demand. If the blast resistance capacity of the seismically designed building can be evaluated, the risk of the blast loading caused due to the terrorist attacks can be reduced by upgrading the seismic design of the building. With this background in view, the present paper investigates the blast resistance capacity of a 6 storey building frame designed for extreme peak ground acceleration (PGA) levels of 0.5g, 0.4g, and 0.3g. The 3D model of the 6 storey building is designed according to Indian Standard (IS) codes for the above mentioned extreme level earthquake. Designed buildings are subjected to surface blast of 500 kg of TNT(trinitrotoluene) at different standoff distances ranging from 5m to 30m. The time histories of the blast loading due to air pressure and ground shock are modeled by those existing literature. A nonlinear time history of analysis (NTHA) of the frame is performed in SAP 2000 for surface blast and the simulated earthquakes from the specified response spectrum in IS code. NTHA results for both cases are compared to evaluate the relative performance of the three different seismically designed buildings to the surface blast loading. The response quantities of interest include maximum drift, maximum top displacement, and number of hinges formed. The results of the study indicate that for the near blast conditions the blast resistance capacity of the building increases with the increase in the PGA values for which the building is designed. By upgrading the seismic design by 0.1g, the blast resistance capacity increases manifold for near blast conditions. Thus, by updating the seismic design of a building, the risk of blast loading in the design may be considerably mitigated.

Gold nanoclusters-engineered dual-emitting nanofibrous film for fluorescent discrimination and visual sensing of explosives

Development of reliable sensors for explosive detection is important to reduce explosion-related safety risks and mitigate widespread environmental concerns. However, it remains highly challenging to achieve on-site detection of multiple analytes in a simple yet efficient way. Herein, a flexible electrospun film-based sensing platform by engineering with dual-emitting gold nanoclusters (AuNCs) has been fabricated for the simultaneous fluorescent detection of two representative explosives, hexanitrohexaazaisowurtzitane (CL-20) and trinitrotoluene (TNT). Particularly, two types of AuNCs with different emission colors (green and red) and surface chemistry are designed, which can specifically respond to trace amounts of two explosives separately. While the presence of CL-20 can remarkably enhance the green emission of l-arginine/6-aza-2-thiothymine-protected AuNCs, the presence of TNT can efficiently quench the red emission of glutathione-protected AuNCs. Consequently, ratiometric fluorescent sensing of CL-20 and TNT can be achieved with these dual-emitting AuNCs (G/R-AuNCs), which exhibits a detection limit down to 0.55 and 2.38 µM, respectively. The distinct “turn on” and “turn off” response patterns of G/R-AuNCs towards two explosives could be harnessed to construct fluorescent “BUF” and “NOT” logic gates. Moreover, the present AuNCs-based explosive sensors were deposited into flexible electrospun nanofibrous film for visual and quantitative detection of CL-20 and TNT, which exhibit good mechanical property and promising sensing performance. This work provides a new approach to design explosive sensing platform by coupling the attractive features of fluorescent AuNCs to the electrospun nanofibrous film, which holds great potential for further practical applications.

Interaction of spatial-Gaussian lasers with the magnetized CNTs in the presence of DC electric field and enhanced THz emission

The interaction of spatial-Gaussian lasers with magnetized carbon nanotubes (CNTs) in the presence of a DC electric field is shown to broaden the surface plasmon resonance effectively. The prime feature of the interaction of lasers with magnetized CNTs is that when the electron cylinder of CNT is shifted with respect to the ion cylinder, the space charge electric field is developed in the overlapped region and results in the restoration force of the electrons. The restoration force along with the ponderomotive and magnetic forces assist to increase the nonlinear current which is further enhanced by the drift velocity acquired by the electrons of CNTs due to the applied static electric field. This action is also responsible for the enhanced THz yield at surface plasmon resonance condition where is the polarization coefficient, is the relative permittivity of the dielectric substrate, is the cyclotron frequency of CNT electrons and is the plasma frequency. The study reveals that THz generation from the magnetized CNTs may be a promising source for the detection of dangerous chemicals like royal demolition explosive (RDX), pentaerythritol tetra-nitrate (PETN), trinitrotoluene (TNT), etc.

Deprotonation of trinitrotoluene by dichloromethane in atmospheric pressure chemical ionization mass spectrometry.

Trinitrotoluene (TNT) and its derivatives are found in the environment. Depending on the analysis conditions, TNT may be detected as a deprotonated molecule or a molecular ion through atmospheric pressure chemical ionization (APCI). Dichloromethane (CH2 Cl2 ) is used as an extraction solvent for TNT from environmental samples and as an ionizing agent to generate chlorinated species. APCI mass spectra of TNT dissolved in CH2 Cl2 revealed the presence of only the [TNT - H]- ion. This phenomenon was investigated by reactions with the CH2 Cl2 -related reactant ions. TNT in CH2 Cl2 was ionized through APCI, and CH2 Cl2 and acetone were used as the eluent. The vaporizing temperature was varied from 200 to 350°C. TNT-related ions and reactant ions were analyzed. Detection limits for TNT were determined under different conditions. Energy-minimized structures of the product ions were used to interpret the analysis results. Significant [TNT - H]- ion was observed, but the [TNT + Cl]- and TNT•- ions were not detected. The [HCl + Cl]- and [3acetone + Cl]- ions were detected as reactant ions when using CH2 Cl2 and acetone as eluent, respectively. Other potential reactant ions such as CH2 Cl2 •- and [CH2 Cl2 + Cl]- were not observed. The detection limit improved as the vaporizing temperature increased. The favorability of [TNT - H]- formation was explained on the basis of the heats of reactions. The [TNT - H]- ion was primarily produced by the deprotonation reaction between CH2 Cl2 •- and neutral TNT. This reaction was determined to be significantly exothermic. CH2 Cl2 can be helpful for the analysis of TNT in environmental samples through APCI mass spectrometry.

Numerical analysis of reinforced concrete buildings subjected to blast load

AbstractThis study deals with a three‐dimensional (3D) nonlinear finite element (FE) analysis of two reinforced concrete (RC) buildings. The first is a three‐floor flat slab building without shear walls. The second is a three‐floor flat slab building with four shear walls. The blast load has been simulated using the coupled Eulerian–Lagrangian (CEL) technique found in the FE software Abaqus/Explicit. Concrete behavior has been modeled using the Johnson–Holmquist damage model (JH‐2) with 3D eight‐node reduced Lagrangian integration elements (C3D8R). The reinforcement steel has been modeled using the Johnson–Cook (JC) plasticity model and the JC computational fracture model with beam elements (B31). Trinitrotoluene (TNT) explosive material has been modeled using the Jones–Wilkins–Lee (JWL) equation of state (EOS) with eight‐node reduced integration Eulerian elements (EC3D8R). Air has been modeled using the EOS for ideal gas with EC3D8R elements. TNT charges of 20, 100, and 1000 kg with standoff distances of 2, 5, and 10 m have been used in the analysis. An analysis has been performed to study the two RC buildings' deformation, stresses, and damage. The results showed that small TNT charges of less than 20 kg with a standoff distance of more than 10 m had almost no effect on the two buildings. Also, huge TNT charges of more than 1000 kg with a standoff distance of less than 10 m had a catastrophic impact on the two buildings.

(2-Vinyltetrazolyl)furoxans as New Potential Energetic Monomers.

A regioselective approach toward the synthesis of a set of new (2-vinyltetrazolyl)furoxans as potential energetic monomers has been realized. All target energetic materials were thoroughly characterized by spectral and analytical methods. Moreover, crystal structures of two representative heterocyclic systems were studied by single-crystal X-ray diffraction. Prepared high-energy substances have high combined nitrogen-oxygen content (63-71 %), high enthalpies of formation and good detonation parameters (D: 6.7-7.8 km s-1; P: 18-28 GPa). Mechanical sensitivities of the synthesized vinyltetrazoles range these explosives from highly sensitive to completely insensitive. Using calculations of molecular electrostatic potentials (ESP), structural factors influencing the impact sensitivity were revealed. Overall, newly synthesized (2-vinyltetrazolyl)furoxans are of interest as promising energetic monomers due to the presence of the vinyl moiety and explosophoric heterocyclic combination, while their performance exceeds that of benchmark explosive TNT.