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ABSTRACT The design and synthesis of insensitive energetic materials are a necessary and challenging work. The synthesis of novel nitrogen‐rich salts based on 5‐(5‐Nitro‐1H‐1,2,4‐triazol‐3‐yl)‐1H‐tetrazole (H2NTT) has been presented. Structural characterization of these two salts was accomplished by utilizing NMR, MS, IR spectroscopy, and X‐ray diffraction. The standard heats of formation were calculated, and the differential scanning calorimetry (DSC) and sensitivity test were carried out. Their detonation performances were estimated by EXPLO 5 program. These newly synthesized salts showed highly positive heat of formation and low sensitivity. It is noteworthy that the diaminoguanidine salt b exhibited good detonation performance superior to traditional explosive TNT (Trinitrotoluene), making it a prospective candidate for insensitive energetic material. [ABSTRACT FROM AUTHOR]

For prompt detection of large (>1 kt) above-ground explosions, infrasound microphone networks and arrays are deployed at surveyed locations across the world. Denser regional and local networks are deployed for smaller explosions, however, they are limited in number and are often deployed temporarily for experiments. With the expanded interest in smaller yield explosions targeted at vulnerable areas such as population centers and key infrastructures, the need for more dense microphone networks has increased. An "attritable" (affordable, reusable, and replaceable) and flexible alternative can be provided by smartphone networks. Explosion signals from a fuel air explosive (thermobaric bomb) and a high explosive with trinitrotoluene equivalent yields of 6.35 and 3.63 kg, respectively, were captured on both an infrasound microphone and a network of smartphones. The resulting waveforms were compared in time, frequency, and time-frequency domains. The acoustic waveforms collected on smartphones produced a filtered explosion pulse due to the smartphone's diminishing frequency response at infrasound frequencies (<20 Hz) and was found difficult to be used with explosion characterization methods utilizing waveform features (peak overpressure, impulse, etc.). However, the similarities in time frequency representations and additional sensor inputs are promising for other explosion signal identification and analysis. As an example, a method utilizing the relative acoustic amplitudes for source localization using the smartphone sensor network is presented. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

As a new structural motif, an interesting 3D energetic metal – framework of silver ions and 3,4-diaminofurazan, [Ag+(daf)NO3−]n, is successfully synthesized and the structure is determined by single-crystal X-ray diffraction. The effects of hydrogen bond, coordination bond, adsorption and filling interactions make this compound have a high density (2.694 g·cm−3 at 293 K). The calculated detonation velocity and the sensitivities are all comparable with trinitrotoluene (TNT). The onset decomposition temperature is equal to hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), state-of-the-art explosive. This framework provides a potential superiority of E-MOFs for energetic materials. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study uses both experimentation and simulation to investigate how varying casing material around cylindrical Composition-B charges affects witness plate response and diagnoses the cause of the differences in the dents produced. Through experimentation, it was found that consistent dents are produced from repeated tests and characteristically different dents are produced by charges with different casing material. Charges cased in viscoelastic materials produced shallower dents than those without casing. Simulation was validated against the experimental dents, and the detonation wave parameters were measured for 25 differently cased charges: 15 metals and 10 polymers. Regression fit relationships were derived relating dent parameters to casing density, casing impedance, casing tensile strength, detonation pressure, detonation velocity, impulse, and time of arrival. Specifically, it was found that the dent volume was negatively correlated with the detonation velocity and the impulse of the detonation wave was negatively correlated with dent depths across the charge. The density of the casing material was shown to be linked to the width of the witness dents. Additional dent tests were simulated for trinitrotoluene (TNT) charges cased in a single polymer and a single metal. The relationships derived for Composition-B were adjusted to fit TNT using TNT equivalency and calculated the measured detonation wave values to within 10% accuracy. Finally, it was concluded that the measurable distinctions observed in the witness dents were not a result of the casing material itself, but of the changes in the detonation wave caused by its interaction with the casing material. [ABSTRACT FROM AUTHOR]

Water decoupling blasting is an efficient method that can significantly improve blasting effects. A three-dimensional (3D) numerical investigation is conducted using the multimaterial Arbitrary Lagrangian Eulerian (ALE) method to deepen the understanding of the method. The blasting effects and pressure attenuation regularities for coupling, air and water decoupling blasting are compared to reveal the fracture mechanism for water decoupling blasting. The simulated results indicate that water is desirable to transmit blasting pressure, because it slows the blasting pressure attenuation and improves the blasting effect. Quantitative analysis of the radial, axial, and radial–axial decoupling charges is performed to optimize the charge structure. The radial decoupling charge is a better charge structure, which results in a more uniform blasting energy distribution. With the increase in the radial decoupled coefficients, the blasting pressure attenuation index first decreases and then increases. The analysis results indicate that 1.5 is the optimal radial decoupling coefficient, which can achieve the highest energy utilization efficiency. The simulated results for radial–axial decoupling blasting show that the rock failure regularities of radial or axial decoupling blasting exist in radial–axial decoupling blasting. By comparing the blasting effect of four commonly used explosives, trinitrotoluene (TNT), which has high blasting pressure, detonation velocity, and initial internal energy density, is the optimal explosive in water decoupling blasting, which is different from coupling blasting. [ABSTRACT FROM AUTHOR]

Melt-cast explosives are the most widely used energetic materials in military composite explosives, researchers have been unremittingly exploring high-energy and insensitive melt-cast explosives. In this work, a series of dinitrophenyl-oxadiazole compounds were designed and prepared. These compounds have an ideal low melting point (80e97 °C), good detonation performance (detonation velocity D ¼ 6455 e6971 m/s, detonation pressure P ¼ 18e19 GPa) and extreme insensitive nature (impact sensitivity ≥60 J, friction sensitivity >360 N). All these compounds were well characterized by nuclear magnetic resonance, fourier transform infrared spectroscopy, elemental analysis. Compounds 2, 3 were unambiguously confirmed by X-ray single crystal diffraction analysis. As a result, their overall properties are superior to traditional melt-cast explosives trinitrotoluene (TNT) and dinitroanisole (DNAN) which may have excellent potential applications in insensitive melt-cast explosives. © 2023 China Ordnance Society. Publishing services by Elsevier B.V. on behalf of KeAi Communications [ABSTRACT FROM AUTHOR]

A new energetic co-crystal of trinitrotoluene (TNT) and pyrene (PYRN) with a 1:1 molar ratio was prepared by a slow solvent evaporation technique. Co-crystal physicochemical properties have also been examined using optical microscopy, powder X-ray diffraction, single crystal X-ray diffraction, and differential scanning calorimetry. The results of single-crystal X-ray diffraction and non-covalent interaction calculations showed that non-covalent interactions (donor–acceptor π-π interaction) govern the structures of the TNT:PYRN co-crystal. The experimental and theoretical outcomes supported each other in the study. Thermal stability, impact sensitivity, and detonation performance of the co-crystal were investigated. DSC measurement indicates that the co-crystal has a melting point of 167 °C and a decomposition temperature of 293 °C, indicating outstanding thermal stability. The co-crystal was found to be less impact-sensitive than TNT using the BAM fall hammer instrument. Furthermore, the calculated detonation velocity and detonation pressure of the co-crystal are 5.29 km·s−1 and 8.48 G Pa, respectively. As an outcome, the TNT:PYRN co-crystal may be a promising intermediate energy explosive with low sensitivity and, as such, may be a desirable explosive alternative in the future instead of TNT for low-vulnerability formulations. [ABSTRACT FROM AUTHOR]

Photonic Doppler velocimetry and digital high-speed shadowgraphy have been used to characterize the chemical reaction zone parameters of pressed trinitrotoluene (TNT) samples with an initial density of 1.568 g cm − 3 . Comparison of the nanosecond time-resolved particle velocity histories of the free surfaces of detonating charges in air and light vacuum and of the interfaces between TNT detonation products and lithium fluoride or polymethyl methacrylate windows allow one to bracket the von Neumann spike pressure between 24.8 and 28.8 GPa. Our velocity waveforms confirm the two-step reaction pathway already observed in TNT, triaminotrinitrobenzene (TATB), and nitromethane, with a first fast energy release over 80 ns followed by a slower release over 250 additional ns. We consider the end of the first release zone as the locus of the Chapman–Jouguet (CJ) state, and the CJ pressure thus lies between 17.6 and 17.7 GPa. The energy release is not completed in this Jouguet plane but only after about ≈ 280 ns when the carbon cluster formation process ends. This corresponds to both the end of the slow release part of the interface velocity profiles and to the moment at which the free surface velocity profiles reach their maximum. Our shadowgraphy images confirm that carbon formation occurs very rapidly after the detonation breakout, in good agreement with previous time-resolved small-angle x-ray scattering measurements. The comparison with similar results previously obtained on TATB allows one to further highlight their similarities, which mainly result from their excess carbon production at late times. [ABSTRACT FROM AUTHOR]

Two compatibility test types based on gas generation obtained by vacuum stability test (VST) procedure and on heat generation obtained by heat flow microcalorimetry (HFMC) show that nitroguanidine (NGu), CAS‐No. [556‐88‐7], is compatible with ammonium nitrate (AN), CAS‐No. [6484‐52‐2], ammonium dinitramide (ADN), CAS‐No. [140456‐78‐6], 1,1‐diamino‐dinitroethylene (FOX‐7, DADNE), CAS‐No. [145250‐81‐3], N‐guanylurea dinitramide (FOX‐12, GUDN, carbamoylguanidinium dinitramide), CAS‐No. [217464‐38‐5], hexogen (RDX), CAS‐No. [121‐82‐4], octogen (HMX), CAS‐No. [2691‐41‐0], and trinitrotoluene (TNT), CAS‐No. [118‐96‐7]. The evaluations with gas generation and heat generation were done using the so‐called corresponding reactivity quantities RV and RQ, but the assessment criteria are in accordance with the present NATO standards. NGu and ADN show the rare case of reactivity with a negative assessment quantity, that is their inter‐component reactivity quantities show negative values in RV and RQ. The evolved gas volume and the produced heat generation of the 1 : 1 mixture have lower values than the formally calculated values of the mixture. The root cause of this cannot be deduced with mere compatibility testing. A negative assessment quantity RQ is also observed with NGu and TNT at 80 °C, but not at 70 °C. [ABSTRACT FROM AUTHOR]

Fluorescence probe technology holds great promise in the application of trace explosive detection due to its high sensitivity, fast response speed, good selectivity, and low cost. In this work, a designed approach has been employed to prepare the TPE-PA-8 molecule, utilizing the classic aggregation-induced emission (AIE) property of 1,1,2,2-tetraphenylethene (TPE), for the development of self-assembled monolayers (SAMs) targeting the detection of trace nitroaromatic compound (NAC) explosives. The phosphoric acid acts as an anchoring unit, connecting to TPE through an alkyl chain of eight molecules, which has been found to play a crucial role in promoting the aggregation of TPE luminogens, leading to the enhanced light-emission property and sensing performance of SAMs. The SAMs assembled on Al2O3-deposited fiber film exhibit remarkable detection performances, with detection limits of 0.68 ppm, 1.68 ppm, and 2.5 ppm for trinitrotoluene, dinitrotoluene, and nitrobenzene, respectively. This work provides a candidate for the design and fabrication of flexible sensors possessing the high-performance and user-friendly detection of trace NACs. [ABSTRACT FROM AUTHOR]

Thin films of trinitrotoluene (TNT) were shock compressed using the ultrafast laser shock apparatus at Los Alamos National Laboratory. Visible (VIS) and mid-infrared (MIR) transient absorption spectroscopies were simultaneously performed to probe for electronic and vibrational changes during shock compression of TNT. Three shock pressures (16 GPa, 33 GPa, and 45 GPa) were selected to observe no reaction, incipient reaction, and strongly developed reactions for TNT within the experimental time scale of <250 ps. Negligible absorption changes in MIR or VIS absorptions were observed at 16 GPa. At 33 GPa, MIR absorptions in the 3000 cm−1–4000 cm−1 range were observed to increase during the shock and continue to increase during the rarefaction, in contrast to the VIS absorption measurements, which increased during the shock and almost fully recovered during rarefaction. At 45 GPa, both VIS and MIR absorptions were strong and irreversible. The intense and spectrally broad MIR absorptions were attributed to short lived intermediates with strong, spectrally broad absorptions that dominate the spectral response. The MIR and VIS absorption changes observed at 33 GPa and 45 GPa were credited to shock induced chemistry, most likely including the formation of a very broad hydrogenic stretch feature. The results from these experiments are consistent with the chemical mechanisms that include O–H or N–H formation such as CH3 oxidation or C–N homolysis. [ABSTRACT FROM AUTHOR]

Desirable advancements in the field of explosive materials include the development of novel melt-castable compounds with melting points ranging from 80 to 110 °C. This is particularly important due to the limited performance and high toxicity associated with TNT (trinitrotoluene). In this study, a series of innovative melt-castable explosives featuring nitratoalkyl and azidoalkyl functionalities attached to the 3-nitro-, 4-nitro-, 3,4-dinitropyrazole, or 3-azido-4-nitropyrazole scaffold are introduced. These compounds were synthesized using straightforward methods and thoroughly characterized using various analytical techniques, including single-crystal X-ray diffraction, IR spectroscopy, multinuclear nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry, elemental analysis, and DTA. Furthermore, the energetic properties such as (theoretical) performance data, sensitivities, and compatibilities of the compounds were evaluated and compared among the different structures. [ABSTRACT FROM AUTHOR]

The results of instrumental observations of acoustic oscillations and geomagnetic variations during the bolide-fall event on April 19, 2023 in the region of Kyiv (Ukraine) are presented. It is shown that the bolide explosion was accompanied by an acoustic signal recorded at a great distance from the epicenter of the event (~755 km) and was manifested in variations in the magnetic field. According to acoustic observations, four explosions of the largest fragments of the bolide were recorded. The total energy of the event was 4.2 × 1011 J, which corresponds to about 0.1 kt in trinitrotoluene (TNT) equivalent. The maximum amplitude of geomagnetic variations caused by the bolide explosion at distances in the range of 454–909 km was 2.5 to 4 nT. [ABSTRACT FROM AUTHOR]

The technology is based on recording the focal activity (FA) of the olfactory bulb (OB) of rats upon the exposure rats to trinitrotoluene (TNT) vapors in the concentration 4.7 × 10–15 g/cm3, separately and in a mixture with saturated vapors of a complex interference composed of spices. The focal activity of the rat olfactory bulb was recorded using an array of 16 special electrodes implanted in the dorsal part of the rat olfactory bulb. The setup contained a box with a rat, sources of vapors (odorants), a multichannel digital system for recording electrical signals from an electrode array, and software performing algorithms for recognizing and classifying odorants presented to the rat. One source of TNT vapors was a device for batch volumetric preparation with a concentration of about 10–15 g/cm3, and another source was a source with a concentration of 4.7 × 10–15 g/cm3 in an air flow presented to rats. Data from 25 tests showed a 100% probability of detecting TNT vapors of the specified concentrations in pure air and also in the presence of a complex odor interference in the form of vapors from a mixture of red pepper, coriander, tobacco, etc., which, as a rule, mask the smell of TNT for animals. [ABSTRACT FROM AUTHOR]

Military operations over large areas of Ukraine lead to release of explosives and their derivatives into the environment with subsequent accumulation in natural and artificial water bodies, which unwittingly serve as reservoirs for collecting pollutants from the catchment area. The need to restore aquatic ecosystems dictates the search for efficient, cost-effective and environmentally friendly methods for the elimination of explosives, which corresponds to the processes of biological treatment. In this work, we examined the ability of common freshwater algae of the genus Rhizoclonium to detoxify 2,4,6-trinitrotoluene (TNT) under model conditions of water pollution (at a TNT concentration of 100 mg/L). The exposure time of the algae to TNT was 48 hours, during which the content of TNT and nitrites in the aqueous medium was monitored, as well as the content of chlorophyll and the activity of glutathione S-transferase in plant tissues. 2,4,6-trinitrotoluene was extracted from the aqueous medium with toluene, followed by separation in a separatory funnel, removal of residual water with sodium sulfate, and reduction of the extract volume using a rotary evaporator. The decrease in the concentration of TNT, established by GC-MS technique, was 66.4% by the end of the experiment, while the content of nitrites increased almost 15-fold. In the algae cells, a threefold increase in the enzymatic activity was observed already in the second hour of exposure, followed by a gradual decrease and maintenance at a level of 50% of the control until the end of the experiment. The total chlorophyll content increased significantly from the sixth hour of exposure to the end of the experiment due to an increase in the content of chlorophyll b. The results obtained indicate the efficient biodegradation process and prospects of using algae of the genus Rhizoclonium for cleaning water bodies contaminated with TNT. [ABSTRACT FROM AUTHOR]

When an explosion occurs close to or partially within the face of a concrete structure, fragments are rapidly launched from the opposite face of the structure owing to concrete spalling, posing a significant risk to nearby personnel and equipment. To study the lead fragment velocity of ultra-high-performance concrete (UHPC), partially embedded explosion experiments were performed on UHPC slabs of limited thickness using a cylindrical trinitrotoluene charge. The launch angles and velocities of the resulting fragments were the determined using images collected by high-speed camera to document the concrete spalling and fragment launching process. The results showed that UHPC slabs without fiber reinforcement had a fragment velocity distribution of 0e118.3 m/s, which are largely identical to that for a normal-strength concrete (NSC) slab. In addition, the fragment velocity was negatively correlated to the angle between the velocity vector and vertical direction. An empirical Eq. for the lead spall velocity of UHPC and NSC slabs was then proposed based on a large volume of existing experimental data. [ABSTRACT FROM AUTHOR]

A new fluorescent probe (T2) containing pyrene-hydrazone furan moieties was developed and synthesized through a two-step process and then coated onto filter paper to form a paper-based sensor for TNT detection. The T2 sensor uses photoinduced electron transfer (PET) induced fluorescence quenching to detect TNT. The sensor properties were studied using fluorescence spectra, 1H-NMR titration and density functional theory (DFT) calculations. The reaction time of the T2 paper-based sensor for TNT detection was only five minutes. A smartphone was used as an alternative instrument to detect fluorescence signals and a typical image J-processing application was employed to evaluate the grayscale values of the smartphone-captured photographs. The sensor showed a linear concentration range for TNT detection of between 30–500 μM and a detection limit of 30 μM. The T2 paper-based sensor was found to have high selectivity and sensitivity, and it can successfully detect and image TNT in actual samples. This research demonstrates that a T2 paper-based sensor is a promising alternative for TNT detection owing to its short reaction time, high selectivity, sensitivity, and easy applicability. [ABSTRACT FROM AUTHOR]

A novel isoxazoline‐based porous adsorbent (PB‐TTNO) is prepared by click polymerization and freeze‐drying from a methyl‐containing bis(nitrile oxide) stable at room temperature. The introduction of four methyl groups around the nitrile oxide group reduces the activity of the bis(nitrile oxide) and make it react more mildly with polybutadiene, resulting in PB‐TTNO with a more uniform pore size. Meanwhile, the electron‐donating methyl groups further increase the π–π interaction between the polymer benzene ring and the TNT benzene ring. The π–π interaction enables one benzene ring in the polymer to interact with two TNT molecules to form a sandwich structure, which further improves the adsorption capacity. The synergistic effect of dual π–π interactions and dipole‐π interactions makes the maximum adsorption capacity of PB‐TTNO reach 235.3 mg g−1 within 12 h at 25°C. The factors such as pH value, adsorbent dosage, contact time, initial TNT concentration, and temperature are also discussed. The adsorption kinetics fit well with the pseudo‐second‐order model, and the Langmuir model exhibits better correlation for equilibrium data analysis. In addition, the adsorption data of PB‐TTNO in real water samples are similar to those in laboratory, and the maximum adsorption capacity decreases by only 15% after five adsorption–desorption cycles. [ABSTRACT FROM AUTHOR]

In this study, two energetic molecules with 1,4,2,5-dioxadiazine as a bridge were created by adding triazoles and pyrazoles to the oxazine skeleton. The structural characteristics, thermal behavior, and explosive properties of the obtained compounds 3,6-bis(1-nitro-1H-1,2,4-triazol-3-yl)-1,4,2,5-dioxadiazine (4a) and 3,6-bis(1-nitro-1H-pyrazol-3-yl)-1,4,2,5-dioxadiazine (4b) were investigated using experimental and theoretical techniques. To further elucidate the structure-property relationship, this study conducted calculations and analyses of quantum chemistry, such as the Hirshfeld surface analysis, the electrostatic potential (ESP) surface analysis, and the localized orbital locator (LOL) calculation. Compounds 4a and 4b have higher detonation velocities (4a: Dv = 8328 m s-1; 4b: Dv = 7681 m s-1) than the conventional explosive 2,4,6-trinitrotoluene (TNT; Dv = 6881 m s-1) according to an energetic evaluation. Moreover, the thermal properties and sensitivities of 4a (Td = 155 °C, IS = 15 J, FS = 288 N) and 4b (Td = 192 °C, IS = 20 J, FS = 216 N) were greatly improved compared with the previously reported energetic furazan-1,4,2,5-dioxadiazine derivatives N,N'-((1,4,2,5-dioxadiazine-3,6-diyl)bis(1,2,5-oxadiazole-4,3-diyl))dinitramide (i; Td = 106 °C, IS = 4.5 J, FS = 100 N) and 3,6-bis(4-nitro-1,2,5-oxadiazol-3-yl)-1,4,2,5-dioxadiazine (ii; Td = 148 °C, IS = 2.2 J, FS = 116 N). The excellent sensitivities and acceptable detonation velocities of compounds 4a and 4b make them good candidates for potential mechanically low-sensitive explosives. These findings will enrich the further application of nitrogen heterocycle 1,4,2,5-dioxadiazine in the field of energetic materials. [ABSTRACT FROM AUTHOR]

Rationale: 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 (CH2Cl2) 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 CH2Cl2 revealed the presence of only the [TNT − H]− ion. This phenomenon was investigated by reactions with the CH2Cl2‐related reactant ions. Methods: TNT in CH2Cl2 was ionized through APCI, and CH2Cl2 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. 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 CH2Cl2 and acetone as eluent, respectively. Other potential reactant ions such as CH2Cl2•− and [CH2Cl2 + 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. Conclusions: The [TNT − H]− ion was primarily produced by the deprotonation reaction between CH2Cl2•− and neutral TNT. This reaction was determined to be significantly exothermic. CH2Cl2 can be helpful for the analysis of TNT in environmental samples through APCI mass spectrometry. [ABSTRACT FROM AUTHOR]

We study the electrical and morphological properties of random arrays of Ge nanowires (NW) deposited on sapphire substrates. NW-based devices were fabricated with the aim of developing chemiresistive-type sensors for the detection of explosive vapours. We present the results obtained on pristine and annealed NWs and, focusing on the different phenomenology observed, we discuss the critical role played by NW–NW junctions on the electrical conduction and sensing performances. A mechanism is proposed to explain the high efficiency of the annealed arrays of NWs in detecting 2,4,6 trinitrotoluene vapours. This study shows the promising potential of Ge NW-based sensors in the field of civil security. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In this study, we report the influence of vanadium oxide (VO), as a photosensitive component, on the photoactivity of TiO2 nanotubes (TNTs). A series of TNTs of varying tube diameter were synthesized by the anodization of titanium foils at different voltages, while vanadium oxide was deposited on TNTs by wet chemical deposition. An improvement in the optical properties of nanotubes was observed after the deposition of vanadium oxide. An improvement in the optical properties (redshift in UV-Vis spectra) of TNTs and TNT/VO was noted. The photocatalytic activity was improved with increasing tube diameter, while it was weakened after the deposition of VO. Furthermore, photoactivity was investigated in photodiodes based on TNTs or TNT/VO and single crystals of CH3NH3PbI3. The photoelectric measurement revealed that different TNT diameters did not influence the I-V characteristic of the photodiodes, while the deposition of VO improved the photocurrent for smaller TNTs. [ABSTRACT FROM AUTHOR]

Redwater is a highly toxic waste generated during the purification of 2,4,6-trinitrotoluene (TNT), one of the most widely used military explosives. Redwater treatment is difficult because of its high chemical oxygen demand (COD) and strong red color. In this study, we present a comprehensive study on the treatment of the actual TNT redwater by a combination of chemical coagulation and electro-Fenton process. The pretreatment by traditional coagulation using poly-aluminum chloride (PAC) was investigated at different operation conditions of solution pH (4–11), PAC concentration (500–3500 mg/L), flocculant concentration (0–3.5 mg/L), times for coagulation (0–7 min) and flocculation (0–4 min), and stirring speed (100–700 rpm). This pretreatment could removal 52.84% of COD, 53.22% of color, 36.76% of TSS, and 25.88% of total nitrogen under optimal conditions (i.e., pH 7.0, PAC dosage of 2500 mg/L, anion flocculant dosage of 1.25 mg/L, coagulation time of 4 min, flocculation time of 1 min, and stirring speed of 500 rpm). The pretreated redwater was then subjected to an electro-Fenton process using Pt/Ti as anode and carbon felt as the cathode. The effects of solution pH (2–6), iron content (0.05–1 mM), current intensity (8.33–33.33 mA/cm2) and reaction times (0–200 min) on the electro-Fenton treatment were investigated. Under optimal condition (i.e., pH 3.0, Fe(II) concentration of 0.1 mM, current intensity of 16.67 mA/cm2, and reaction time of 120 min), the removal efficiency reached 87.07, 96.2, 72.94, and 50.26% for COD, color, TSS, and total nitrogen, respectively. UV-Vis spectroscopy results confirmed the role of electro-Fenton for the effective removal of aromatic nitro compounds in the redwater. These results suggest that the combination of coagulation and electro-Fenton process could be a promising technology for treating TNT redwater. [ABSTRACT FROM AUTHOR]

A mathematical model of sublimation (evaporation) of thin films of explosives is presented based on the molecular-kinetic theory of evaporation. An expression is obtained for the film evaporation time until equilibrium between the evaporation and condensation of explosives is reached. An estimate of the unevaporated mass is given. A parametric study of the model has been carried out. The evaporation dynamics for a film of trinitrotoluene (TNT) with a surface density of 100 ng/cm2 on the glass is calculated. The trinitrotoluene sublimation heat and the evaporation coefficient from the glass have been determined based on a comparison with the experiment on evaporation of this TNT film. [ABSTRACT FROM AUTHOR]

Excitation-emission orthogonalized luminescent upconversion nanoparticles (OUCNPs), which can respond to changes in external stimuli accordingly, show great promise in many intelligent applications. However, the construction of such materials mostly relies on the selective absorption of Nd3+ and Yb3+ at different wavelengths and the long-range energy migration between the layers, resulting in complex structures and limited orthogonal luminescence intensity. Herein, we developed a relatively simple structure of OUCNPs (β-NaErF4@NaLuF4@NaYF4:20%Yb, 2%Er@NaLuF4), where the fluorescence emission switches from red to green when the excitation wavelength is shifted from 808 to 980 nm. This structure exhibits high-quality, independent, and non-interfering orthogonal luminescence properties without Nd3+ sensitization and long-range energy migration. As a proof of concept, we demonstrate the application of the designed OUCNPs in anti-counterfeiting. We also prepared OUCNPs@PEI (PEI = polyethylenimine) self-referencing fluorescent probes to enable quantitative analysis of trinitrotoluene (TNT) in solution with a detection limit of 3.04 µM. The probes can be made into test strips for portable on-site visual detection of TNT, and can also be used to image latent fingerprints and detect explosive residues in fingerprints simultaneously. The concept proposed in this work can be extended to the visual detection of a larger range of organic and biological molecules, and is highly promising for practical applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel strain of Pantoea sp. showed efficient degradation of TNT. • Genomic studies reveal the TNT metabolism-related genes of Pantoea sp. BJ2. • Proteomics identifies differential proteins in TNT degradation by Pantoea sp. BJ2. • Metabolite analysis reveals metabolites of TNT degradation by Pantoea sp. BJ2. • Multiomics analysis reveals the degradation mechanism of TNT by Pantoea sp. BJ2. Trinitrotoluene (TNT) is a highly toxic organic pollutant, and its biodegradation process and mechanism remain unclear. In this study, five TNT-degrading bacteria were isolated and identified, among which Pantoea sp. BJ2 showed the best TNT degradation potential; it could degrade 97.85 % of 100 mg L−1 TNT within 24 h. Further, five genes (three nemA , one nfsA and one nfnB) directly related to TNT metabolism were identified in Pantoea sp. BJ2. During the degradation of TNT by Pantoea sp. BJ2, N-ethylmaleimide reductase, nitrate reductase and ATP-binding protein of the nitrate/nitrite transport system were found to be significantly upregulated, and five metabolites, including 2-amino-4,6-dinitrotoluene, were also identified. Based on the multiomics analysis, the mechanism of TNT degradation by Pantoea sp. BJ2 was proposed, indicating that the degradation of TNT by Pantoea sp. BJ2 was achieved under the joint action of various functional genes and proteins, including material transport, energy supply and exogenous material metabolism. The findings offer reliable theoretical underpinnings and technical support for a safe remediation of TNT-contaminated sites, providing new insights into the microbial degradation mechanisms of TNT from a multiomics perspective. [ABSTRACT FROM AUTHOR]

Phytoremediation is considered as an early and active technique, which plants used to clean a wide range of organic and inorganic pollutants. Study was laid out to detect the effect of different levels of toluene and various concentration of silver and their effect on nanoparticles for phytoremediation and how to influence the vegetative growth characters of potato. A farm experiment was done in lath house in the farm of Horticulture and Garden Architecture Department, College of Agriculture, University of Anbar for the spring season 2021, to study the effect of phytoremediation of potato, Class Burren of elite order. Different levels of tri-nitro toluene were added with different concentrations of nanosilver particles directly into soil according to the study treatments and variation. Results stated the superiority of treatment T8 (500 mg kg-1 soil TNT+500 mg kg-1 NPs) to give maximum height 61.56 cm with a highest average leaves number as 47.66 leaves. plant, in addition to the dry weight 55.02 gm and stems number 3.66 for the same treatment, in addition to give a highest dry substance percentage as 16.55%, compared with the control treatment that recorded (36.06 cm, 41.6, 33.32 g, 2.33, 13.27%) successively; while the treatment T7 recorded highest leaf area of 119.79 dcm². It could be derived that the treatment at level (500x500 TNT-NPS) possessed a positive effect on potato vegetative growth characters. [ABSTRACT FROM AUTHOR]

In this work, a visual colorimetric method for the rapid and selective detection of triacetone triperoxide is reported. This visual colorimetric method is based on the reaction between potassium titanyl oxalate and hydrogen peroxide (H2O2) released from triacetone triperoxide degradation. Potassium titanyl oxalate can selectively react with H2O2 to form peroxo-titanic acid (an orange complex), enabling the colorimetric detection of triacetone triperoxide. Based on the theory that triacetone triperoxide produces hydrogen peroxide under acidic conditions, acid types, acid concentration, response time, visual limit of detection, and reactants ratio are systematically studied simultaneously for this colorimetric method. Under sulfuric acid concentration is 60%, the proposed method can almost detect triacetone triperoxide instantly, and the color of the solution reaches the maximum within 1 min and remains stable with a visual limit of detection as low as 3.0 × 10−5 mol/L. Interference experiments were carried out on other kinds of explosives (hexamethylene triperoxide diamine, trinitrotoluene, etc.). The use of colorimetric card brings great convenience to the rapid, qualitative, and semi-quantitative on-site detection of triacetone triperoxide. Because of its rapidity, high sensitivity, simplicity, and selectivity, the proposed visual colorimetric method can serve as a valuable and promising reference for triacetone triperoxide's rapid, qualitative on-site detection. [ABSTRACT FROM AUTHOR]

Encapsulation is proposed as a safer way of handling energetic materials. Different encapsulation methods for explosives, such as solvent evaporation, spray coating and supercritical carbon dioxide assisted encapsulation, were explored. Explosive training aids, where energetic materials, such as triacetone triperoxide (TATP), erythritol tetranitrate (ETN) and trinitrotoluene (TNT), are encapsulated in a polymer matrix were developed, followed by comprehensive quality control testing, including differential scanning calorimetry (DSC), thermogravimetric analysis-infrared spectroscopy (TGA-IR), gas chromatography-mass spectrometry (GC-MS), high-resolution mass spectrometry (HRMS) and sensitivity testing, and finally field approved by canine units trained on the pure explosive. [ABSTRACT FROM AUTHOR]

The recovery of latent prints from post-blast improvised explosive device (IED) components can link a bomb maker to a specific device after an explosion occurs. Here, different combinations of IED substrates were assembled, spiked with latent prints, and detonated using trinitrotoluene (TNT), C-4, and ammonium nitrate and aluminum (ANAL). Latent prints (187) were developed on the post-blast IED components, resulting in a 63% latent print recovery. The substrates yielding the most developed latent prints were black vinyl tape, metal, and clear packing tape. The IEDs prepared with C-4 resulted in the highest percent recovery of latent prints; IEDs prepared with ANAL resulted in the least. Of the latent prints detected, 63% were determined to be suitable for comparison by qualified latent print examiners. This study demonstrates the value of processing post-blast IED components for latent prints using a variety of laboratory techniques, identifies the substrates most conducive for latent print recovery, and determines the effect of different explosive types on the recovery of latent prints. [ABSTRACT FROM AUTHOR]

[Display omitted] • Thienothiophene (TT) based AIE probes for explosives; trinitrotoluene (TNT), dinitrotoluene (DNT) and trinitrophenol (TNP). • 2.9 x 104 of maximum Stern-Volmer constant. • 90% of TNP quenching sensitivity. • Visual detection on the absorbent paper. Sensors for selective and sensitive detection of nitroaromatic (NAC) explosives are of current interest for both national security and environmental protection. In this work, three thienothiophene based AIE active materials (TPE2-TT, TPE3-TT and TPE3-TPA-TT), possessing tetraphenylethylene and triphenylamine units, were designed and synthesized as chemosensors for sensitively detecting 2,4,6-trinitrotoluene (TNT), 2,4-dinitrotoluene (DNT) and trinitrophenol (TNP) explosives. Among the AIEgens, TPE3-TT demonstrated a maximum Stern-Volmer constant (K sv) reaching to 2.9 x 104 M−1 by quenching response toward TNP. They exhibited vivid visual quenching on absorbent papers. Moreover, probe-explosive complex interactions and their mechanisms were investigated using density functional theory (DFT). Their remarkable properties indicated that TT based AIEgens are promising probes for sensitively detecting the explosives, which provided a new source of potential leading to new designs for detection of explosives. [ABSTRACT FROM AUTHOR]

• Charcoal-based AC was modified with Fe NPs via a carbothermal process. • TNT q max of AC, AC-800, and Fe-AC-800 were 265.52, 339.64, and 387.74 mg/g. • The Fe NPs and carbothermal treatment favored TNT adsorption on Fe-AC-800. • The optimal adsorption capacity of Fe-AC-800 was 464.13 mg/g. • The mechanism of TNT adsorption involved π-π EDA interaction and hydrogen bonding. Activated carbon (AC) is commonly used to remove many pollutants from water due to its appealing adsorption properties. However, the pristine surface properties of AC limit its ability to effectively remove 2,4,6-trinitrotoluene (TNT, a widely used explosive water contaminant). Modifying AC with Fe nanoparticles (NPs) can significantly improve the surface properties of the Fe/AC composite, thereby enhancing its adsorption capabilities. Commercial charcoal-based AC was modified with Fe NPs via wet impregnation followed by a one-step carbothermal synthesis (labeled Fe-AC-800). A detailed characterization of Fe-AC-800 and its counterparts, pristine AC and thermally modified AC (AC-800, without Fe NPs doping) was performed using XRD, Raman Spectroscopy, SEM, EDS, BET, XPS, and FTIR. Then, the adsorption characteristics and performances of Fe-AC-800 were analyzed to determine its effectiveness in removing TNT and compared to AC and AC-800, considering the impact of in-situ Fe-modification and carbothermal treatment. Fe-AC-800 displayed a higher adsorption capacity for TNT (387.74 mg/g) than the pristine AC (265.52 mg/g) but only slightly higher than AC-800 (339.64 mg/g). This was ascribed to the combined effect of the carbothermal treatment and Fe NPs doping, which constructed a richer porous structure that improved the Fe-AC-800 surface features and favored TNT removal. The optimal adsorption capacity of Fe-AC-800 was 464.13 mg/g under ambient conditions. TNT adsorption onto Fe-AC-800 and AC-800 conformed to only the Langmuir isotherm model, indicating uniform monolayer adsorption, whereas on the pristine AC, it satisfied both Langmuir and Freundlich isotherm models, respectively. The primary mechanism of TNT adsorption onto Fe-AC-800 was physical adsorption through pore filling, hydrogen bonding, and π-π EDA interactions, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

• PUC2 Luminescent Probe: utilizing MOF PUC2 for TNT detection. • Sensitivity: achieving a 0.145 μM detection limit. • pH Adaptability: effective in pH 4–11 aqueous environments. • Distinctive Blue Emission: vivid blue light enhances accuracy. • Quenching Mechanisms: PET and FRET for sensitivity. The existence of nitroaromatic compounds, specifically 2,4,6-trinitrotoluene (TNT), in water reservoirs poses significant health risks, necessitating robust detection and monitoring strategies. In this study, we leverage the exceptional properties of the previously synthesized metal-organic framework (MOF), PUC2 as a highly luminescent probe for selective and sensitive detection of TNT in aqueous media. PUC2 exhibits remarkable luminescence, emitting a vivid blue light, making it an ideal candidate for TNT detection. Our investigations reveal that PUC2 demonstrates outstanding sensitivity, achieving an impressive detection limit of 0.145 μM towards TNT which can be attributed to the robust probe-analyte interactions evident from the quenching constant (Ksv) value of 0.18 × 104 M −1. An intriguing aspect of PUC2 is its adaptability to a wide pH range, maintaining its sensing capabilities effectively in aqueous phase with pH levels ranging from 4 to 11. The predominant quenching mechanism in this context appears to be photoinduced electron transfer (PET), with an additional enhancement through Forster resonance energy transfer (FRET). The unique combination of structural features and exceptional sensing capabilities of PUC2 opens up new avenues for environmental monitoring and security applications, highlighting its potential as a highly effective luminescent sensor for detecting hazardous substances like TNT. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper presents the development and optimization of a cost-effective paper electrochemical sensor for the detection of TNT using Fe 3 O 4 –Au core-shell nanoparticles modified with cysteamine (Fe 3 O 4 @Au/CA). The sensor was constructed by modifying a graphite paste with the aforementioned nanoparticles, which facilitated the formation of a Meisenheimer complex between cysteamine and TNT as an electron donor and an electron acceptor, respectively. The central composite design was employed to optimize four key parameters pH, modifier percentage, contact time, and buffer type to enhance the performance of the sensor. The detection limit was found to be 0.5 nM of TNT, while the linear range of the electrode response spanned from 0.002 μM to 10 μM. The simplicity and low cost of the sensor make it highly attractive for practical applications, particularly in scenarios where rapid and on-site TNT detection is required. [Display omitted] • Fabrication of a paper-based TNT sensor based on the Meisenheimer complexation. • Synergistic effect of Fe 3 O 4 @Au NPs improves the sensor's electrochemical properties. • The RSM-CCD optimization approach was used for the statistical optimization. • The detection limit of the sensor was 0.5 nM in the linear range of 0.002–10 μM. • The developed sensor can detect TNT in aqueous and soil samples, without extraction. [ABSTRACT FROM AUTHOR]

Samples of trinitrotoluene (TNT) and erythritol tetranitrate (ETN) were exposed to nanosecond pulses from a tunable laser source across 90 minutes. During this continued laser pulse exposure, the samples of TNT underwent heavy degradation while the samples of ETN were able to resist high energy densities without visible alteration. A degradation pathway involving a nitro-nitrite rearrangement is suggested for the TNT, which sees radical production result in carbon 'char' formation in the explosive, despite there being no signs of bulk or surface melting. The formation of this carbon-explosive mixture and its implications towards the safety of extended exposure laser sensing techniques is discussed. [ABSTRACT FROM AUTHOR]

The organic gunshot residues (OGSRs), specifically methyl centralite (MC; 1,3‐dimethyl‐1,3‐diphenylurea), ethyl centralite (EC; 1,3‐diethyl‐1,3‐diphenylurea), 2,4‐DNT (2,4‐dinitrotoluene), and TNT (trinitrotoluene), are characteristic compounds for which forensic analysts test determining if a person has discharged a firearm. A set of 200 samples from 50 shooters were collected as part of the validation study. Pistol 9 mm and special revolver.38 were fired at indoor and outdoor shooting ranges. The development of a methodology based on direct analysis of samples‐time of flight‐mass spectrometry (DSA‐TOF‐MS) made it possible to identify the main components of organic shot residues, which gave the possibility to introduce a new method of analysis of shot residues in the Chilean supply area. The DSA‐TOF‐MS provided extensive information on the composition of the shot residues: MC, EC, 2,4‐DNT, and TNT. Samples taken from the trigger hands required minimal sample preparation that reduced analyses time. With the implementation of new alternative analytical methodologies, a great step would be taken in the analysis of OGSRs, because now there is no such technique for its analysis in Chile, and the results would also complement the existing inorganic elemental analyses generated during a gunshot. [ABSTRACT FROM AUTHOR]

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Naphthalimide‐hydroxyquinoline based conjugates (NQ1 and NQ2) were synthesized for the detection of nitroaromatics in HEPES buffer/DMSO (9/1, v/v, pH=7.4) and Fe3+/Pd2+ in CH3CN solvent. The NQ1 and NQ2 were characterized using NMR (1H, 13C, COSY) and IR spectroscopies. Theoretical studies revealed that 8‐HQ moiety in NQ1 and NQ2 placed at orthogonal position with respect to naphthalimide core to minimize steric crowding. The energy gap between HOMO and LUMO for NQ1 and NQ2 were found to be −3.1 eV. The emission spectrum of NQ1 and NQ2 showed decrease in the emission intensity at 450 nm upon addition of picric acid (PA) and trinitrotoluene (TNT) whereas addition of 2‐nitroaniline caused quenching with concomitant red‐shift of the emission band in 90 % HEPES buffer‐DMSO. The detection limit of NQ1 for PA, TNT and 2‐NA detection was calculated as 8.7×10−6 M, 2.2×10−5 M and 1.8×10−5 M. The complexation of NQ1 with PA, TNT and 2‐NA was further supported by Job's plot, dynamic light scattering studies and NMR titrations. We successfully utilized NQ1 and NQ2 for the detection of PA, TNT and 2‐NA in real soil samples with excellent recovery. NQ1 also showed quenching of the emission intensity at 450 nm upon addition of Fe3+ and Pd2+ ions in CH3CN. Thus, NQ1 showed solvent‐dependent dual chemosensor type behavior. The functioning of NOR gate has been achieved using Fe3+/NACs with NQ1. [ABSTRACT FROM AUTHOR]

Nitroaromatic explosives are the most common explosives, and their detection is important to public security, human health, and environmental protection. In particular, the detection of solid explosives through directly revealing the presence of their vapors in air would be desirable for compact and portable devices. In this study, amino-functionalized carbon nanotubes were used to produce resistive sensors to detect nitroaromatic explosives by interaction with their vapors. Devices formed by carbon nanotube networks working at room temperature revealed trinitrotoluene, one of the most common nitroaromatic explosives, and di-nitrotoluene-saturated vapors, with reaction and recovery times of a few and tens of seconds, respectively. This type of resistive device is particularly simple and may be easily combined with low-power electronics for preparing portable devices. [ABSTRACT FROM AUTHOR]

In order to study the overpressure distribution law of a shock wave under the dynamic explosion of a cylindrical charge and the influence of the charge speed on the overpressure distribution law, a trinitrotoluene (TNT) cylindrical bare charge was selected. Additionally, a numerical simulation of a cylindrical charge explosion under different motion speeds was carried out using the AUTODYN finite element software. The results showed that during the static explosion of a cylindrical charge, the shock wave propagates outward in the form of an ellipsoid, whereas under the dynamic explosion, the shock wave overpressure field is an irregular ellipsoid, and the shock wave overpressure zone shifts to the velocity direction. With an increase in the charge velocity, the peak value of the shock wave overpressure increases gradually in the moving direction. The simulation data were analyzed, revealing that the calculation model of the dynamic explosion shock wave overpressure field of a cylindrical charge with a scaled distance of 1 m·kg−1/3 ≤ R ¯ ≤ 1.5 m kg−1/3 can provide a reference basis for the study of dynamic explosion shock waves. [ABSTRACT FROM AUTHOR]

Blast pressure from a small electric detonator, comprised of 100-mg lead azide as its main explosive, was measured and its trinitrotoluene (TNT)􀀎equivalency was evaluated accordingly. The measurement of blast pressure in the proper direction suppressed oscillatory noise on the blast wave profile; therefore, the blast pressure from the sole detonator was clearly and definitively evaluated. The relationships between scaled distance and peak􀀎overpressure, as well as scaled positive impulse, were compared to those of MITI87, which is representative of TNT surface􀀎explosion data obtained by National Chemical Laboratory for Industry (National Institute of Advanced Industrial Science and Technology at present) in Japan. The TNT-equivalency of this detonator was conclusively evaluated as 0.32-0.33. [ABSTRACT FROM AUTHOR]

Heterocyclic skeleton (Azoles) and different energetic groups containing high performing explosives are highly emerged in recent years to meet the challenging requirements of energetic materials in both military and civilian applications with improved performance. For this purpose tetrazole (Azole) is identified as an attractive heterocyclic backbone with energetic functional groups nitro (-NO2), nitrato (-ONO2), nitrimino (-NNO2), and nitramino (eNHeNO2) to replace the traditionally used high performing explosives. The tetrazole based compounds having these energetic functional groups demonstrated advanced energetic performance (detonation velocity and pressure), densities, and heat of formation (HOF) and became a potential replacement of traditional energetic compounds such as RDX. This review presents a summary of the recently reported nitro-tetrazole energetic compounds containing poly-nitro, di/mono-nitro, nitrato/nitramino/nitrimino, bridged/bis/di tetrazole and nitro functional groups, describing their preparation methods, advance energetic properties, and further applications as highperforming explosives, especially those reported in the last decade. This review aims to provide a fresh concept for designing nitro-tetrazole based high performing explosives together with major challenges and perspectives. [ABSTRACT FROM AUTHOR]

The core-shell 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane/2,4,6-Trinitrotoluene (CL-20/TNT) composite was prepared by spray-drying method in which sensitive high energy explosive (CL-20) was coated with insensitive explosive (TNT). The structure and properties of different formulations of CL-20/TNT composite and CL-20/TNT mixture were characterized by scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Laser particle size analyzer, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), differential scanning calorimetry (DSC), impact sensitivity test and detonation performance. The results of SEM, TEM, XPS and XRD show that e-CL-20 particles are coated by TNT. When the ratio of CL-20/TNT is 75/25, core-shell structure is well formed, and thickness of the shell is about 20e30 nm. And the analysis of heat and impact show that with the increase of TNT content, the TNT coating on the core-shell composite material can not only catalyze the thermal decomposition of core material (CL-20), but also greatly reduce the impact sensitivity. Compared with the CL-20/TNT mixture (75/25) at the same ratio, the characteristic drop height of core-shell CL-20/TNT composite (75/25) increased by 47.6% and the TNT coating can accelerate the nuclear decomposition in the CL-20/TNT composites. Therefore, the preparation of the core-shell composites can be regarded as a unique means, by which the composites are characterized by controllable decomposition rate, high energy and excellent mechanical sensitivity and could be applied to propellants and other fields. [ABSTRACT FROM AUTHOR]

A multidimensional numerical study was performed to explore the ignition and combustion mechanisms of an annular aluminum particle shell surrounding a trinitrotoluene (TNT) charge. The model equations consist of a fully compressible reacting gas coupled to a kinetic-theory-based Eulerian granular multiphase model. The parametric study explored the influence of thickness of the Al particle layer, initial Al packing, and diameter of the Al particles. The computed results show ignition and flame structures that are consistent with both delayed and prompt ignition of explosively dispersed reactive powder. In delayed ignition, the Al particles ignite several milliseconds after the dispersal when the particles interact with the surface of the TNT fireball during the negative phase of the blast. The resulting turbulent Al dust flame propagates from the inside toward the outside of the dispersed Al dust cloud. The results show that smaller-diameter Al particles ignite more quickly and propagate through the dispersed dust cloud more rapidly. Paradoxically, larger amounts of smaller Al particles are unburned after the turbulent flame propagates through the dust cloud in comparison to larger-diameter particles. Prompt ignition occurs when the Al particles ignite in the shock-heated air almost immediately as the particles start to disperse. The flame structure for prompt ignition scenarios is a non-premixed dust flame where the fuel and air are mixed by velocity slip between the gas and particles. [ABSTRACT FROM AUTHOR]

The microhardness of the {001} faces of 2‐4‐6 trinitrotoluene crystals has been investigated using both Vickers and Knoop indentation methods. The Vickers hardness number was found to be 22.5 kg mm−2 independent of crystal orientation and perfection. At ambient temperatures (∼20 °C) the Knoop hardness number varied between 20.5 kg mm−2 and 24.0 kg mm−2 with crystal orientation. At higher temperature (50 °C) the Knoop hardness anisotropy curve retained its shape, although the overall hardness decreased by 10 %. We interpret this change as reflecting a simple temperature dependant loosening of the crystal lattice rather than any change in deformation mechanism. No variation of Knoop hardness was evident with changing load. The hard direction was [010] and the soft [100]. The dominant operative slip system was defined to be {001}[010]. [ABSTRACT FROM AUTHOR]