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Gas gun shock experiments on cyclotrimethylenetrinitramine (RDX)-based explosive compositions that employ embedded gauge particle velocity tracers have noted a significant amount of electrical noise when compared to other explosive formulations. This paper reexamines previously published embedded gauge data on Cyclotols (60–80 wt. % RDX) to quantify the electromagnetic behavior of these materials. The primary observation is a fourfold increase in the electrical noise when Cyclotols are shocked above 4.22 ± 0.08 GPa. Electromagnetic gauge noise is also observed within particle velocity traces in reactive growth and off-Hugoniot shocks, although at higher pressures than the direct shock case, suggesting a temperature- or kinetically dependent transition. In all cases, the electrical noise disappears upon detonation. By comparing with the static high-pressure phase diagram of RDX, we interpret this change in electromagnetic behavior to be a change in the RDX crystal structure to a piezoelectric phase, although it is uncertain whether the γ or ε phase is responsible for the observed behavior. [ABSTRACT FROM AUTHOR]

With large-scale non-equilibrium molecular dynamics simulations and in situ x-ray diffraction analysis, we conducted a systematic investigation into the effects of pre-existing shear strain (γ x y ) on the shock response of single crystal iron. Our findings reveal significant effects of γ x y on the deformation of the crystal structure during shock loading, leading to noticeable alterations in the propagation of shock waves. Specifically, during the elastic stage, the presence of γ x y results in a reduction of shock strength, consequently diminishing the magnitude of elastic lattice strain (ε e ). In the plastic stage, γ x y stimulates the α – ε phase transformation, and structure deformation undergoes a transition from the sequential activity of dislocation-to-transformation to the synchronous activity of dislocation and transformation. This transition inhibits the propagation of plastic waves and consequently broadens the elastic regime. Additionally, the introduction of γ x y activates different slip systems, as it alters the corresponding resolved shear stress. Concurrently, the presence of γ x y triggers the activation of different high-pressure phase variants. Our investigation sheds light on the fundamental physics of iron under shock compression and the influence of pre-existing shear strain on its behavior. [ABSTRACT FROM AUTHOR]

An extension of a constitutive law for 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) is proposed with a focus on the calibration of a crystal plasticity law. TATB, a highly anisotropic energetic molecular crystal used in explosive formulations, can be subjected to high-pressure and high-temperature conditions, either under high strain-rate deformation or shock loading. The existing thermodynamically consistent model, fully informed by molecular dynamics (MD) simulations, includes nonlinear elasticity as well as a phase-field by reaction pathway formalism under large strain for the modeling of TATB behavior upon pressure as well as its well-known twinning–buckling deformation mechanism. However, it has been observed that TATB single crystal can accommodate large deformations through dislocation-mediated plasticity, a feature not included in the mesoscale model. In the present work, we take advantage of the microscopic flow surface, previously computed through MD calculations, to calibrate a crystal plasticity law, extending the capability of the continuum model currently limited to low velocity impacts and moderate strain rate. Indeed, the microscopic flow surface, defined as a 3D stress-at-first-defect-nucleation contains all information about TATB single crystal mechanical response under directional shear loading, including twinning, buckling, and plastic events. The calibration process uses differential evolution optimization to calibrate TATB basal and transverse slip systems critical stresses to reproduce the microscopic flow surface. Finally, the response of a TATB single crystal to directional loading is investigated in order to evaluate the new model. [ABSTRACT FROM AUTHOR]

Air refractive index alteration is an important research technique used to examine blast density and pressure. However, precise time-course measurements of refractive index changes at a fixed point caused by air blast waves are challenging due to the necessity for high precision and noise immunity. This study proposes a dual-probe, dual-frequency fiber-optic displacement interferometer that achieves nanometer-level accuracy and can tolerate light intensity fluctuations and transmission-fiber interference. The specially designed sensor enables the measurement of refractive index at a fixed point resulting from explosive-driven air blast waves, further allowing for obtaining the pressure and density information. [ABSTRACT FROM AUTHOR]

The behavior of energetic materials is significantly influenced by the spatial distributions of microstructure heterogeneities and voids. We pursue the concept of Functionally Graded Energetic Materials whose microstructure features (e.g., grain size, grain volume fraction, void size, and void volume fraction) change spatially such that they may allow the behavior of the materials to be tailored. We explore using gradients in the density of voids to alter the detonation behavior of a polymer-bonded explosive (PBX) echoing PBX9501 with HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) grains and Estane binder. Five cases, two graded void distributions from 1% to 10% and 10% to 1% by volume along the length of the sample, and three uniform distributions matching the lowest (1%), average (5.5%), and highest (10%) void densities are considered. An Arrhenius reaction burn model is used to account for the chemical kinetics of HMX. Different detonation behaviors are obtained from the same graded sample when impact loading is from 1% void end and from the 10% void end as well as from the uniform cases. The SDT (shock to detonation transition) behaviors are analyzed in terms of the run distance, the time duration and shock velocity changes over the SDT process. The computational results are presented in the context of available experimental data for PBX9501 with which agreement is obtained through a parametric study. Overall, it is shown that gradients in microstructures of PBX can lead to SDT behaviors different or not obtainable from microstructures without gradients, thereby offering a mechanism for designing and tailoring new materials. [ABSTRACT FROM AUTHOR]

The shock-to-detonation transition properties of the triaminotrinitrobenzene based PBX 9502 high explosive (HE) are experimentally and computationally explored in extremely high input pressure conditions. These include both slightly sub-Chapman–Jouguet and overdriven input pressure conditions, namely, ∼ 25 and ∼ 31 GPa, respectively. Our experiments capture the transient buildup of a shock-induced reaction via measurement of HE and polymethyl methacrylate window interface particle velocity profiles for a variety of sample thicknesses for this insensitive HE. These observations necessitate extremely thin explosive samples, and the high rates of reaction provide a considerable challenge to optical diagnostics. Samples at these thicknesses also provide an opportunity for evaluation of potential micro-structure effects on the resulting shock-to-detonation-transition measurements. To address this, the thin samples are also characterized via x-ray micro-computed tomography. Finally, a pair of previously established continuum-level detonation performance modeling approaches for PBX 9502 were used to analyze the experiments. The employed model variants crucially differ in their definition of each model's empirical reaction rate functional form, utilization of shock state quantities, and local flow variable dependencies. As a result, the present experiments provide a novel platform to evaluate the quantitative and qualitative consequences stemming from these modeling choices in a challenging initiation scenario, largely beyond the chosen calibration range of either model. This new experimental information will provide a platform for both improved physics and model parameterizations for this well-studied explosive. [ABSTRACT FROM AUTHOR]

The non-uniform distributed pressure of impact wave is usually simplified into concentrated or uniform load equivalently in the optimization design of constrained layer damping structure. However, for the thin-walled structure, it becomes necessary to regard the load as a non-uniform distribution. In this paper, a topology optimization approach is proposed considering the blast load with non-uniform distribution, aiming to unveil its impact on optimization layouts and dynamic responses. Initially, the smoothed particle hydrodynamics (SPH) algorithm is used to obtain the blast pressure what are extracted and integrated into the optimization model. Subsequently, the relative density is regarded as design variable. The construction of material penalty model and the topology optimization model are based on polynomial interpolation scheme (PIS). The sensitivity of objective function is deduced employing an improved adjoint variable method (AVM) to fit the load forms, and the Newmark- β method is used to calculate the dynamic response. The optimization criterion (OC) is adopted to update the design variables. Finally, two numerical examples are used to exhibit the validity and accuracy of the presented methodology. The findings indicate that the distributed form, spread velocity, excited position and excited amplitude of the blast load all exert a notable influence on optimization results and dynamic response. These results underscore the valuable engineering application of this research and introduce a fresh perspective to the challenge of topology optimization under the blast case. [ABSTRACT FROM AUTHOR]

This study designs a blasting loading device capable of changing the utilization of explosive gas by modifying the constraint conditions. The propagation of crack and stress waves in red sandstone under different explosive gases is recorded using digital image correlation technology and ultra‐dynamic strain gauges. Both methods are effectively validated against each other. The results showed that as the utilization of explosive gas increases, the explosive stress wave induces layer cracking at the specimen's far end and tensile failure at its near end. In addition, the larger the stress wave's amplitude, the greater the spatial attenuation coefficients of the compression and tension waves. The study ultimately deduces the propagation process of the incident wave and analyzes the influence of stress wave propagation on the specimen's failure characteristics. [ABSTRACT FROM AUTHOR]

When analyzing military, defense, or structures/infrastructures deemed critical, explosion‐induced actions—often associated with malicious actions—play a significant role. The combined effect of a blast and fire is not uncommon: in fact, an explosion can be the extreme consequence of a fire or vice versa, a fire can occur as the result of an explosion. Although advanced numerical approaches can be a proper solution for analyzing critical structures and infrastructures subjected to accidental actions, their complexity makes these approaches unsuitable for the analysis of ordinary buildings or even for the preliminary design of structures. A pressure–impulse diagram is an easy and common tool that can be adopted to verify the safety of structural members for a wide range of blast scenarios even considering the damage caused by a previous fire. This study aims to compare different approaches that can be adopted for the construction of pressure–impulse diagrams of reinforced concrete structures subjected to a blast and a blast preceded by fire. Taking as a reference case a statically indeterminate beam with three supports, this work presents the influence of the methods of analysis on the safety level assessed through pressure–impulse diagrams. [ABSTRACT FROM AUTHOR]

This article explores the use of deep learning, specifically artificial neural networks, to optimize the parameters of laser shock peening in the Ti-6Al-4V alloy. Laser shock peening is a technique that introduces compressive residual stresses to improve the fatigue properties of materials. The authors develop a neural network model that accurately predicts residual stresses and depth of the modified layer. The model can be used to identify optimal processing parameters for achieving maximum depth and compressive stresses. The study concludes that the neural network predictions align with experimental results. [Extracted from the article]

Under the influence of geostress, the thick hard sandstone roof layer at the upper end of the mining area is prone to faults, rockbursts, and sudden collapses during deep coal mining. Blasting top-cutting and depressurization technology centered on over-the-top deep hole blasting is an important method for this type of dynamic disaster control. To characterize the pore structure of sandstone damaged by blast loads and the change in energy dissipation in different pressure environments, specimens with different degrees of blasting damage were measured via nuclear magnetic resonance (NMR) spectroscopy. A triaxial test loading device was used to carry out compression tests on undamaged, vibration-damaged, and blast-damaged specimens under different pressures. The effects of blast load and confining pressure on the porosity, pore structure, energy dissipation, and fracture morphology characteristics of sandstone specimens were analyzed. (1) The T2 spectral curves of the sandstone specimens were all bimodal, and the signal intensity of the main peak was much greater than that of the secondary peak. The peak T2 spectrum curves of the blast-damaged specimens and vibration-damaged specimens were 1.21 and 1.14 times greater than those of the undamaged specimens, respectively, and the mean values of the peak relative area were 1.11 and 1.20 times greater than those of the undamaged specimens, respectively. The number of internal pores in the specimens increased significantly after blast loading. (2) The pore structure distributions in the sandstone specimens were dominated by the proportions of micropores and small holes. The blast load changed the internal pore ratio structure of the specimen, transformed the small holes into medium holes and large holes, and increased the porosity of the specimen. (3) Blast load damage could reduce the energy absorption and energy storage effects of sandstone specimens and weaken roof sandstone and reduce the stress concentration. Furthermore, the impact of the blasting damage area was greater than that of the vibration damage area. (4) With increasing confining pressure, the fracture degree of the specimen first decreased and then increased. Due to the high-energy storage abilities of the undamaged specimens, the macroscopic rupture degrees of the undamaged specimens were greater than those of the specimens damaged by vibration and blasting. The blasting load will cause damage to the roof sandstone to achieve the effect of pressure relief, so as to reduce the occurrence of geological disasters such as roof fault and rock burst. [ABSTRACT FROM AUTHOR]

Shock wave propagation and their damage to solid structures, which involve complex multiphase and multiphysics phenomena, are difficult problems to address. In this paper, a three-dimensional graphics processing unit (GPU)-accelerated finite difference-smoothed particle hydrodynamics (FD-SPH) method was developed for the prediction of strongly compressible fluid flow and strong fluid-structure interactions. The conventional mesh-based finite difference method was used to simulate shock wave propagation, while the smoothed particle hydrodynamics method was employed to predict the dynamic behavior of solid materials. In addition, the immersed boundary method (IBM) was implemented in the GPU-accelerated FD-SPH solver for the boundary treatment of the interface between solid and fluid materials. Four numerical cases, namely shock-cylinder obstacle interaction, elastic panel deformation induced by shock wave propagation, the response of stainless steel tubes under internal blast loading, and the damage of blast loading on reinforced concrete slab, were conducted for verification of the GPU-accelerated FD-SPH solver. The numerical results were compared against the available experimental data, which shows that the GPU-accelerated FD-SPH solver is capable of capturing the shock wave propagation and its damage to structures very well. • A GPU accelerated coupled FD-SPH method is developed to solve strong fluid-structure interaction problems. • The immersed boundary method is used in the solver to impose boundary conditions on the fluid-structure interface. • The propagation of shock waves and its damage to the structure is well captured. [ABSTRACT FROM AUTHOR]

The present study investigates the stability of a tunnel subjected to blast loads. The tunnel is placed in a transversely isotropic rock mass. Numerical simulations are performed using the discrete-element method. The rock material between the bedding planes/joints is discretized as Voronoi polygons. The research focuses on the significance of discretizing the rock material between the bedding planes as Voronoi polygons for studying a tunnel's stability under blast loads. To this end, the influence of Voronoi polygon size, joint spacing, anisotropy angle, cover depth, and earth pressure coefficient on the tunnel response are examined. The tunnel response is measured in terms of normalized crown displacement. The study provides many novel insights that can be used to improve the design of rock tunnels. It is found that it is vital to discretize rock grains as Voronoi blocks for studying the tunnel response. When Voronoi blocks are considered, the tunnel stability increases for anisotropy angles 30° and 60° but decreases for angles 0° and 90° when no Voronoi blocks are used. The tunnel becomes more vulnerable to damage as the Voronoi block size increases. It is noted that the joint spacing and Voronoi block size are interlinked, and their influence must be considered together for assessing the tunnel stability. When joint spacing is kept twice or more than the Voronoi size, the crown displacement is higher than when joint spacing is equal to or closer to the Voronoi size. It is observed that the crown displacement is maximum when the earth pressure coefficient equals 2. Therefore, the influence of change in the earth pressure coefficient is considered the most severe of all the parameters studied. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced polymers (CFRP) are recognized for their exceptional strength-to-weight ratio. They offer a viable and effective solution for strengthening and retrofitting masonry bridges, helping to extend their service life, improve structural performance, and meet modern safety and load requirements. Wrapping of CFRP around masonry elements can enhance their confinement and ductility. This flexibility plays a crucial role in preventing sudden brittle failure, allowing for controlled deformation, which is essential for blast resistance. Additionally, CFRP materials possess the ability to flex and absorb energy, which proves beneficial in containing and redistributing forces generated during an explosion, consequently reducing the risk of catastrophic failure. This study employed the coupled Eulerian–Lagrangian (CEL) technique available in the finite element software Abaqus/Explicit to simulate the blast loads. Various detonation scenarios were considered, taking into account factors such as location and their impacts on bridge structures. A detailed micro-model was developed using finite element software and accurate geometric data acquired from FARO laser scanning of the case study. The properties of masonry units and backfill were characterized using the Johnson-Holmquist II damage model and Mohr–Coulomb criteria. The Jones-Wilkins-Lee equation of state (EOS) was applied to replicate the behavior of trinitrotoluene (TNT). In accordance with the JH-II model, the researchers formulated a VUMAT code. The study examined the distinct damage mechanisms and overall structural responses of bridges. By evaluating the blast resistance of individual bridge models, the most critical scenarios were pinpointed. Carbon Fiber Reinforced Polymer (CFRP) was then utilized as a method to fortify bridges against blast loads. A comparison was made between the damage propagation before and after the reinforcement. [ABSTRACT FROM AUTHOR]

Blasting is the primary method for ultra-deep roadway engineering, which is facing the challenge of low footage caused by unsatisfactory blasting effects. Among all the evaluation indicators, the blast-hole utilization rate is the most important index for measuring blasting effect. Consequently, accurately predicting this index is essential for improving roadway excavation efficiency. In recent decades, the field applications of artificial intelligence have emerged as the prime method, yet the issue of data loss and large errors in large-scale data processing remains unresolved. In this study, novel Structured Nonlinear Support Vector Machine (SNSVM) is introduced as the primary research tool. To enhance prediction performance and accuracy, Genetic Algorithm (GA), Particle Swarm Optimization (PSO) and Sparrow Search Algorithm (SSA) are utilized to optimize the hyperparameters of SNSVM. The prediction models comprise fourteen influencing factors, constituting the comprehensive blasting effect prediction system based on artificial intelligence. The principal criteria for assessing the performance of various models are the error correlation coefficients (Root Mean Square Error (RMSE), Mean Absolute Percentage Error (MAPE), R-Square (R2)) and the Receiver Operating Characteristic (ROC) curve (standard deviation rate (γ)). Among the models considered, SSA-SNSVM exhibited the greatest capability when the swarm size is 90. The RMSE, MAPE and R2 values of training datasets are 0.0070, 15.54% and 0.9295, respectively. The RMSE, MAPE and R2 values of testing datasets are 0.0086, 16.37% and 0.9490, respectively. Furthermore, the minimum standard deviation rate of SSA-SNSVM serves as the vital index for measuring the accuracy, with a value of 0.11. Subsequently, the sensitivity analysis results indicate that the most sensitive factor of blast-hole utilization rate is the surrounding rock itself. The comprehensive blasting effect evaluation is of significant importance for the dynamic adjustment of on-site blasting schemes, including roadway excavation, shaft excavation, or pressure-relief engineering. [ABSTRACT FROM AUTHOR]

Aluminum is used in the composition of many high explosives and contributes to their blast effect. This work focuses on the study of the combustion of a single isolated particle of size between 30 and 100 µm in an arbitrary atmosphere, whose pressure and composition are chosen to be close to those encountered in a high-explosive fireball. This gaseous atmosphere is still largely unreferenced, and this work aims to provide a better understanding of combustion in this environment. The use of an electrostatic levitator coupled with multi-spectral pyrometric diagnostics enables us to select a single particle and measure its temperature during combustion. Photomultipliers (PMs) are used to follow the temporal evolution of the particle's light emission during combustion. In this work, we also used PMs as pyrometric devices to measure temperature. The diagnostic allows us to determine the temporal evolution of the integrated temperature of the condensed phase during combustion of the aluminum particle. By way of example, a temperature of 3300K was obtained for the combustion of Al in air at 1 bar. The data collected will also be used to verify the assumptions made in the combustion models (e.g. temperature stability during combustion). [ABSTRACT FROM AUTHOR]

In this paper, we numerically investigate the dynamic response and explosion resistance of gradient aluminum foam sandwich tubes subjected to external blast loads. Based on 3D-Voronoi technology, we construct density-graded aluminum foam cores to systematically explore the influence of core density distribution, density gradient, and average relative density on the protective performance of these structures. Our primary objective is to identify optimal design parameters that maximize explosion mitigation capabilities while balancing energy absorption and specific energy absorption capacities. The research results show that a positive gradient core configuration exhibits superior anti-explosion performance, significantly outperforming its uniform and negatively graded counterparts, particularly when the gradient value is substantial. For the positive gradient cores, an increase in the gradient value leads to a corresponding enhancement in explosion resistance. Conversely, in negatively graded cores, a higher gradient value diminishes the anti-explosion performance. Furthermore, while augmenting the relative density of the core layer does improve the overall explosion resistance of the sandwich tube, it comes at the cost of reduced energy absorption and specific energy absorption capabilities, highlighting the need for a delicate balance among these competing factors. [ABSTRACT FROM AUTHOR]

In this work, theoretical and numerical studies of the dynamic response of a fiber–metal laminate (FML) sandwich beam under uniform blast loading are conducted. On the basis of a modified rigid-plastic material model, the analytical solutions for the maximum deflection and the structural response time of FML sandwich beams with metal foam core are obtained. Finite element analysis is carried out by using ABAQUS software, and the numerical simulations corroborate the analytical predictions effectively. The study further examines the impact of the metal volume fraction, the metal strength factor between the metal layer and the composite material layer, the foam strength factor of the metal foam core to the composite material layer, and the foam density factor on the structural response. Findings reveal that these parameters influence the dynamic response of fiber–metal laminate (FML) sandwich beams to varying degrees. The developed analytical model demonstrates its capability to accurately forecast the dynamic behavior of fiber–metal laminate (FML) sandwich beams under uniform blast loading. The theoretical model in this article is a simplified model and cannot consider details such as damage, debonding, and the influence of layer angles in experiments. It is necessary to establish a refined theoretical model that can consider the microstructure and failure of composite materials in the future. [ABSTRACT FROM AUTHOR]

AbstractIn 2022, the World Health Organization (WHO) and International Consensus Classification (ICC) recognized TP53 as an entity-defining alteration in myeloid neoplasms, yet with differing criteria that could lead to discrepant diagnoses and affect clinical trial eligibility. We studied 67 patients with TP53 mutant myeloid neoplasms, reclassifying them using both criteria. While most cases fulfill the criteria for TP53 mutant defined entities, most discrepancies were found in cases with ≥20% blasts. Patients were stratified into three groups based on blast count (<10%, 10–19%, and ≥20%) which revealed comparable clinicopathologic features, genetic characteristics, and outcomes. Notably, patients with ≥10% blasts had shorter overall survival compared to those with <10% blasts (8.1 vs. 12.4 months; p = 0.03). This study is among the few to examine TP53 mutant myeloid neoplasms as a single entity and suggests that the 10% blast count threshold could serve as a gateway to a more harmonized classification for these patients. [ABSTRACT FROM AUTHOR]

AbstractThis study investigates the dynamic response of masonry bridges under blast-induced shock waves, focusing on the structural integrity and safety of these critical infrastructure components under extreme conditions. The research employs theoretical approaches to analyze the effects of blast-induced shock waves on masonry bridge structures. A comprehensive numerical simulation framework is developed using finite element analysis (FEA) to model the dynamic interactions between blast waves and the masonry materials. Key parameters, including the blast load intensity, duration, and distance from the blast source, are varied to assess their impact on bridge performance. The results reveal significant insights into the deformation patterns, stress distribution, and potential failure modes of masonry bridges under blast loading scenarios. The findings underscore the importance of incorporating blast resistance measures in the design and retrofitting of masonry bridges to enhance their resilience against explosive events. This study contributes to the advancement of safety standards and design guidelines for masonry bridge structures in the context of blast loading, providing valuable information for engineers, policymakers, and infrastructure managers. [ABSTRACT FROM AUTHOR]

To reduce the number of casualties in explosion accidents, blast-resistant shelters can be used to protect personnel in high-risk areas of petrochemical processing plants. In this work, the deformation behaviours of uncoated and polyurea-coated blast-resistant plates were studied through gas explosion tests. An ANSYS/LS-DYNA model of a polyurea-coated shelter was established, and the dynamic responses of the shelter under various explosion loads were analysed. A series of fuel–air explosion tests were carried out to investigate the explosion resistance of the full-scale shelter. The results showed that compared with the uncoated blast-resistant plate, the deformation of the polyurea-coated blast-resistant plate was significantly reduced. The overall deformation of the shelter was the central depression of the wall and the inward bending of the frame. The damage effect of a typical high-overpressure, low-duration load was greater than that of typical low-overpressure, long-duration load. The shelter remained intact under three repeated explosive loads, with cracks appearing on the inner wall but no collapse or debris splashing. The shock wave attenuation rate of the shelter reached over 90%, which could significantly reduce the number of indoor casualties. [ABSTRACT FROM AUTHOR]

Introduction Auditory injuries induced by repeated exposures to blasts reduce the operational performance capability and the life quality of military personnel. The treatment for blast-induced progressive hearing damage is lacking. We have recently investigated the therapeutic function of liraglutide, a glucagon-like peptide-1 receptor agonist, to mitigate blast-induced hearing damage in the animal model of chinchilla, under different blast intensities, wearing earplugs (EPs) or not during blasts, and drug-treatment plan. The goal of this study was to investigate the therapeutical function of liraglutide by comparing the results obtained under different conditions. Materials and Methods Previous studies on chinchillas from two under-blast ear conditions (EP/open), two blast plans (G1: 6 blasts at 3–5 psi or G2:3 blasts at 15–25 psi), and three treatment plans (blast control, pre-blast drug treatment, and post-blast drug treatment) were summarized. The auditory brainstem response (ABR), distortion product otoacoustic emission (DPOAE), and middle latency response (MLR) recorded within 14 days after the blasts were used. Statistical analysis was performed to evaluate the effect of liraglutide under different conditions Results ABR threshold shifts indicated that the conditions of the EP and open ears were substantially different. Results from EP chinchillas indicated that the pre-blast treatment reduced the acute ABR threshold elevation on the day of blasts, and the significance of such an effect increased with the blast level. Liraglutide-treated open chinchillas showed lower ABR threshold shifts at the later stage of the experiment regardless of the blast levels. The DPOAE was less damaged after G2 blasts compared to G1 when pre-blast liraglutide was administrated. Lower post-blast MLR amplitudes were observed in the pre-blast treatment groups. Conclusions This study indicated that the liraglutide mitigated the blast-induced auditory injuries. In EP ears, the pre-blast administration of liraglutide reduced the severity of blast-induced acute damage in ears with EP protection, especially under G2. In animals with open ears, the effect of liraglutide on the restoration of hearing increased with time. The liraglutide potentially benefits post-blast hearing through multiple approaches with different mechanics. [ABSTRACT FROM AUTHOR]

Accidental burst of hydrogen pipeline can generate highly destructive blast wave, highlighting the importance of predicting the blast wave intensity for industrial safety and protection. However, current methods for predicting overpressure fail to consider the coupling effect between the blast wave and dynamic rupture. Therefore, a fluid-structure-rupture coupling model is constructed to address this limitation. The accuracy of the model is verified through a comparison of fracture morphology, crack propagation, and internal pressure decay between the simulation and experimental results. On this basis, the effects of dynamic rupture on blast wave formation and propagation, overpressure decay histories, and peak overpressure are investigated. Results indicate that the traditional CFD method tends to overestimate the peak overpressure in the near field while underestimating it in the middle and far fields. Furthermore, it is discovered that the blast waves from bursts of hydrogen pipelines with different diameters exhibit a consistent decay law under the same burst pressure by defining dimensionless distance and peak overpressure. Accordingly, the dimensionless blast curve is proposed for predicting overpressure from hydrogen pipeline burst with diameters ranging from 250 mm to 1000 mm and burst pressures ranging from 4 MPa to 12 MPa. The results can serve as a reference for the accurate and fast evaluation of blast wave intensity from hydrogen pipeline burst. • The proposed model effectively couples the dynamic rupture and blast wave. • Propagation of blast wave from hydrogen pipeline burst is quantitatively depicted. • Previous methods underestimate the peak overpressure in the middle and far fields. • Blast curve is developed to improve the prediction accuracy of peak overpressure. [ABSTRACT FROM AUTHOR]

The characteristics and parameter dependences of blast loading on solid and porous structures subject to explosions in a confined space are numerically investigated based on a shock tube configuration wherein the explosive source is approximated by a section at the closed end of the tube filled with high pressure gases. Using a four-way coupling compressible gas–solid numerical method, this work reveals the explicit correlations between the wave dynamics and the characteristic features of blast loading during the shock impinging transient state and the long-time steady state. Upon the shock impingement, the blast loading on the solid and porous structures both exhibits impulsive features caused by the reciprocating shock and rarefaction waves with moderate and considerable amplitude declines, respectively. The imprints of first several impulses manifest the complex wave propagations between the closed end of the tube and the surfaces of solid or porous structures. The pressure profile on the solid structure soon transitions into a shape consisting of periodic triangular waves with sharp jump fronts and unvaried amplitudes. In contrast, the peak overpressure and amplitude of impulses experienced by the porous structure undergo a significant decay so that a gradual declining loading defines the long-term blast loading. The differences of blast loading between the solid and porous structure can be attributed to the substantial energy loss due to the gas filtration inside the porous structure which becomes more intensive as the porosity is increased. Compaction of the porous structure also plays a significant role since the receding porous surface contributes to the marked dissipation of reflected waves. We further investigate the parameter dependences of the defining features of the blast loading on the solid and porous structure, including the explosion energy, the space between explosion source and the structure, and the porosity as well. [ABSTRACT FROM AUTHOR]

This paper presents an innovative experimental method for studying the evolution and energy output characteristics of underwater explosion bubbles. We independently constructed an experimental testing system for underwater electrical wire explosions (UEWE), in which electrodes connected to a metal wire serve as the load, and underwater explosions are initiated through instantaneous high-voltage discharge. By varying the diameter of the metal wire and configuring parallel wire arrays, we analyzed and discussed the explosion characteristic parameters and the current–voltage (I–V) signals under different conditions. The maximum bubble radius of the underwater metal wire explosion was compared with the corresponding equivalent explosive simulation results, and a numerical model for underwater metal wire explosion equivalent to explosive detonation was established. Subsequently, we discussed the characteristics of bubble generation and evolution under various conditions, clarifying the similarities and differences between wire explosions and explosive detonations. On this basis, we explored the propagation laws of shock waves and secondary pulsation waves (SPW) under different conditions. We also calculated and analyzed energy output characteristic parameters, such as shock wave energy and bubble energy. The results indicate that there are significant differences between copper wire and aluminum wire loads in UEWE. For copper wires with a diameter greater than 0.4 mm, the shock wave overpressure peak value significantly decreases, while for aluminum wires with a diameter greater than 0.5 mm, it slightly decreases. Both metals exhibit similar trends in parallel wire arrays, with the shock wave overpressure peak value initially increasing and then decreasing as the number of wires increases. Unlike underwater explosive detonations, the SPW peak value in UEWE may exceed that of the shock wave. For single wires, the SPW peak value of copper wires is generally higher than that of aluminum wires, but in wire arrays, the trend is reversed. The multi-wire parallel connection can improve the energy conversion efficiency of the shock waves. However, for bubble energy, under all conditions, a single aluminum wire with a diameter of 0.5 mm produced the maximum bubble energy, reaching 1023.1 J. These findings provide new insights into the energy features of UEWE. [ABSTRACT FROM AUTHOR]

The technique of multi-long-hole blasting with large empty holes has been used in practice to break rock mass. However, the damage mechanism of rock mass surrounded by empty holes and boreholes under this type of blasting has not yet been well-understood and identified, which may lead to inappropriate design of the configurations of empty holes for multi-long-hole blasting. The present study investigates the damage modes and mechanism of rock mass under multi-long-hole blasting with large empty holes by conducting a field test and numerical simulations. The results show that multi-long-hole blasting with empty holes mainly causes compressive damage of rock mass around boreholes, reflected tensile damage near empty holes and ground surface, bending-induced tensile damage between empty holes and boreholes, shear damage along the side tangents and bottom of empty holes and boreholes, and tensile damage along the connection of boreholes caused by the superposition of stress waves. In addition, parametric studies are conducted to examine the effects of depths and diameters of empty holes and the spacing between boreholes and empty holes on the damage and fragmentation of rock mass under blast loads. It is found that the flexural stiffness and confined levels of rock mass can be greatly influenced by the variation of configurations of empty holes, which thus induces different damage and fragmentation under multi-long-hole blasting. Analytical formulas for the evaluation of shear and bending-induced damage of rock mass under multi-long-hole blasting are finally proposed to provide references for the design of empty holes in multi-long-hole blasting. Highlights: Damage modes and mechanisms of multi-long-hole blasting with large empty holes are identified. Rock fragmentation characteristics under this blasting are examined. Effects of configurations of empty holes on the performance of multi-long-hole blasting are revealed. Analytical formulas are developed to evaluate rock damage under this blasting. [ABSTRACT FROM AUTHOR]

Methane in situ explosion fracturing can induce intricate fracture networks by detonating methane desorbed from deep shale reservoirs. Elucidating the fracture propagation mechanisms under high-pressure gas explosive loading, along with the predominant controlling factors and interactions between different factors, remains imperative for optimizing fracturing efficacy. This study first established a method for calculating the explosion characteristic parameters in the in situ reservoir environment and determined the dynamic constitutive model parameters for Wufeng–Longmaxi shale. Then numerical simulation model of methane explosion fracturing in the in situ shale reservoir was established. Then response surface methodology was used to design numerical experiments and analyze the effects of explosive loading, in situ stress, and stress difference on the fracturing efficiency. A dimensionless factor Fmef was proposed for the comprehensive evaluation of the fracturing efficiency to elucidate the control mechanisms of the three factors. Lastly, the influence mechanisms of various factors on fracture growth are discussed from the perspective of coupled interactions between methane explosion loads and in situ stresses. The results demonstrate that the fracturing network can be delineated into smash district, damage zone, fracture zone, and vibration zone under gas explosive loading. With peak explosive pressure lower than the shale dynamic compressive strength, no smash district or damage zones appear, and increasing explosive loading markedly enlarges the extent of smash, damage, and fracture zones. The explosive loading predominantly affects the smash district and damage zone, whereas the stress state primarily influences the fracture zone. The response surface analysis with Fmef reveals convex surfaces for both the in situ stress-explosive loading interaction and the stress differential–explosive loading interaction, due to the quadratic effect of the explosive loading. Increasing explosive loading initially positively influences fracturing efficiency, transitioning to a negative impact, while in situ stress and stress differential show a monotonically decreasing trend. Stress analysis showed that the in situ stress significantly suppresses fracture propagation induced by the explosion. Differential stress induces concentration in both vertical and horizontal directions around the wellbore, resulting in longer fracture length and stable propagation time along the maximum principal stress direction. The difference between the primary controls for compressive–shear failure in smash district and tensile failure in fracture zone is explained by the coupled interactions of dynamic loads and in situ stresses. By correlating reservoir pressure and stress state with stimulation success, the constructed response surface model offers a theoretically sound basis for identifying optimal formations for methane explosion fracturing. Highlights: A methane in-situ explosion fracturing technique by detonating methane desorbed from in-situ shale reservoirs is proposed. Established a calculation method for methane-oxygen explosion characteristic parameters under high-temperature and high-pressure reservoir conditions. Calibrated the dynamic constitutive model parameters for Wufeng-Longmaxi shale in the major shale gas producing zones in China The fracturing efficacy in shale reservoirs first increases and then decreases with rising methane explosive loading. The fracturing efficacy of methane explosion fracturing in shale reservoirs is inversely correlated with the in-situ stress and stress difference. [ABSTRACT FROM AUTHOR]

Tunnelling using drilling and blasting method inevitably disturbs the surrounding rock and induces a blasting damaged zone around the tunnel. Conventional mechanical analyses assume that the entire ground is damaged, leading to an underestimation of the surrounding rock stability and a conservative support design of the tunnel. This study developed a new analytical model to analyze the displacement, stress, and plastic radius of tunnels reinforced by grouted rockbolts considering the blasting damage effect. The blasting damaged zone was assumed to take a cylindrical shape with a finite radius. First, four different states of an unsupported tunnel based on the plastic zone distribution within the damaged and undamaged zones were distinguished and solved. Subsequently, ten different forms of a bolt-supported tunnel considering the ground state at bolt installation and the relative ranges of the bolt length and plastic zone were established. A method for determining the evolution paths of these possible forms for a specific tunnel project was developed using the critical displacements and longitudinal positions that define the transition between the different states and forms. Finally, an analytical algorithm for the rockbolt–surrounding rock interaction was established by introducing the concept of a fictitious pressure to simulate tunnel advancement. The proposed analytical model was verified by 3D numerical simulation and field monitoring results. Illustrative examples were presented to investigate the effect of the bolt length on tunnel displacement in both hard and soft rocks. Finally, the performance and advantages of the proposed model were investigated by comparing with the conventional analytical model. The proposed method can be used in the rockbolt design of tunnels constructed using the drilling and blasting method. Highlights: Interaction between rock and grouted rockbolts considering blasting damage zone is analyzed. Ground reaction curves for four different ground states and ten forms are derived. Analytical algorithm for possible evolution paths and critical transitions is presented. Effects of blasting damage zone and bolt length on tunnel displacement is illustrated. Proposed model validated by numerical and field test results excels existing models in rockbolts design. [ABSTRACT FROM AUTHOR]

The growing threat of accidental and malevolent blast loading to building structures has necessitated the consideration of blast-resistant design. Columns are the most vulnerable and critical component of a building, so they must be designed against blast to achieve defined performance goals. The influence of transverse rebar detailing on the ultimate capacity and failure modes of rectangular reinforced concrete (RC) columns against blast loads was investigated under different detonation scenarios. The performance of the columns was quantified using the failure charge mass and post-blast residual axial capacity. Pressure–impulse diagrams were used to study the failure modes. The analyses showed that special transverse detailing measures were the most effective for columns subjected to near-field surface bursts. The confinement of concrete due to ties and axial restraint played a critical role in improving the blast performance of columns. The provision of diagonal rebar improved the blast resistance by preventing direct shear failure, and was most effective when coupled with closely spaced lateral ties. Finally, the performance of code-compliant columns against blast was studied to determine the blast safety margin and the scenarios under which it would be necessary to undertake blast retrofitting of the columns in existing critical buildings. [ABSTRACT FROM AUTHOR]

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In underground mines, development headings such as tunnels and access are essential structures of mining infrastructure. Blasting is the most preferred excavation method for ore and waste rock extraction. Many parameters can significantly influence blast pull performance (BPP); some are controllable (blast design, deviation factor), while others are uncontrollable, such as geological-geomechanical parameters. The current study investigates the influence of cut design, deviation factor (Df), and rock mass quality on BPP. For this purpose, a field investigation was conducted in an underground copper mine to ascertain the influence of geological-geomechanical parameters on BPP. Experimental and numerical analysis reveals a significant relationship between the deviation factor and the borehole length, and it is recommended that the distance between the empty hole and the first burden should be less than 0.15 m to optimize the blasting effect. Furthermore, different statistical analyses were established, and the BPP was directly correlated to the geological strength index (GSI) with two to four joint families. The powder factor is related to BPP for cut designs Bc1/B'c1 and Bc3/B'c3 for medium-quality rocks. In addition, a linear regression model was used to determine the relationship between the powder factor and the GSI. [ABSTRACT FROM AUTHOR]

Recent industrial explosions globally have intensified the focus in mechanical engineering on designing infrastructure systems and networks capable of withstanding blast loading. Initially centered on high-profile facilities such as embassies and petrochemical plants, this concern now extends to a wider array of infrastructures and facilities. Engineers and scholars increasingly prioritize structural safety against explosions, particularly to prevent disproportionate collapse and damage to nearby structures. Urbanization has further amplified the reliance on oil and gas pipelines, making them vital for urban life and prime targets for terrorist activities. Consequently, there is a growing imperative for computational engineering solutions to tackle blast loading on pipelines and mitigate associated risks to avert disasters. In this study, an empty pipe model was successfully validated under contact blast conditions using Abaqus software, a powerful tool in mechanical engineering for simulating blast effects on buried pipelines. Employing a Eulerian-Lagrangian computational fluid dynamics approach, the investigation extended to above-surface and below-surface blasts at standoff distances of 25 and 50 mm. Material descriptions in the numerical model relied on Abaqus' default mechanical models. Comparative analysis revealed varying pipe performance, with deformation decreasing as explosion-to-pipe distance increased. The explosion's location relative to the pipe surface notably influenced deformation levels, a key finding highlighted in the study. Moreover, quantitative findings indicated varying ratios of plastic dissipation energy (PDE) for different blast scenarios compared to the contact blast (P0). Specifically, P1 (25 mm subsurface blast) and P2 (50 mm subsurface blast) showed approximately 24.07% and 14.77% of P0's PDE, respectively, while P3 (25 mm above-surface blast) and P4 (50 mm above-surface blast) exhibited lower PDE values, accounting for about 18.08% and 9.67% of P0's PDE, respectively. Utilising energy-absorbing materials such as thin coatings of ultra-high-strength concrete, metallic foams, carbon fiber-reinforced polymer wraps, and others on the pipeline to effectively mitigate blast damage is recommended. This research contributes to the advancement of mechanical engineering by providing insights and solutions crucial for enhancing the resilience and safety of underground pipelines in the face of blast events. [ABSTRACT FROM AUTHOR]

To investigate the quasistatic pressure load characteristics of an explosion in a confined cabin in a water mist environment, explosion tests were conducted under different explosive and water mist masses. The concentration of water mist, droplet diameter, and quasistatic pressure inside the cabin were measured. On the basis of the theoretical model of quasistatic pressure in adiabatic ideal gas cabins, a theoretical model of the quasistatic pressure in a confined cabin in a water mist environment was established. On the basis of experimental data and theoretical models, an empirical formula was proposed for the peak quasistatic pressure of implosion in a water mist environment. A model for a cabin explosion in a water mist environment was established, and the load characteristics of a cabin explosion under high water mist concentrations were analyzed. The relevant research results contribute to the prediction of the quasistatic pressure of explosions in a confined cabin in a water mist environment. [ABSTRACT FROM AUTHOR]

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Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study of blast loads on structures is important due to the potential of significant consequences in various scenarios. From terrorist attacks to industrial accidents, comprehending how structures respond to blast waves is critical for ensuring public safety and designing resilient structures. Studying these effects typically involves two main methods: free-field tests with live explosives and shock tube tests. Although shock tube testing offers certain advantages, both approaches are costly and demand significant space. This research aims to develop a cost-effective and straightforward technique for generating stress waves that closely replicate the progressive and spatial characteristics of free-field or shock tube blast waves. This method was designed to evaluate the dynamic response of laminated glass panels. The stress wave was generated by impacting a piston on the fluid inside a tube, which was connected to a fluid chamber. This setup produced impulsive loads that were distributed across a laminated glass test panel. Moreover, it was used to simulate the shock near filed explosions for a certain part of a structure. High-speed cameras were utilized to analyze the initial velocity of flying glass fragments. The apparatus successfully produced various blast waves and impulsive profiles for different drop weight heights. The initial velocities of randomly selected flying shards ranged from 3 m/s to 4 m/s. [ABSTRACT FROM AUTHOR]

In order to investigate the dynamic response and rock mass damage characteristics of cavities with different shapes under blasting loads, this paper, through a combination of model tests and numerical simulations, studies the stress distribution, strain, failure modes, and blasting fragment size distribution of cavities with different shapes subjected to blasting loads. The results show that under the action of blasting loads, the presence of cavities with different shapes significantly affects the blasting effects and rock mass damage. Spherical cavities exhibit excellent blast resistance, whereas rectangular and triangular cavities are prone to stress concentration at their tips, which in turn promotes rock mass damage and failure. Subsequent analysis of the blasting fragment sizes reveals that rectangular and triangular cavities yield more favorable blasting results than spherical cavities. The research findings provide important theoretical foundations and practical guidance for the design and construction of underground engineering blasting, contributing to enhancing engineering safety and promoting the sustainable development of the underground engineering industry. [ABSTRACT FROM AUTHOR]

The blast resistance of a typical two-lane steel girder highway bridge structural system was modeled using a nonlinear finite-element approach that considered material damage, fracture, and separation. Critical blast scenarios were based on field observations of terrorist attacks on bridges in Iraq, while system failure was defined in terms of practical emergency serviceability criteria used on actual blast-damaged bridges. The blast resistance of various design parameters was assessed, including the number of girders, deck concrete strength, reinforcement ratio, slab thickness, girder and reinforcement yield strength, girder sectional dimensions, and pier column width. The presented approach uniquely quantifies structural system blast resistance in terms of the charge weight that can be applied at different locations until failure. A sensitivity analysis was conducted to determine the most influential design parameters. It was found that system blast capacity was primarily influenced by the number of girders and girder yield strength, while additional significant parameters were deck compressive strength, deck thickness, web stiffener width, and girder depth. Secondary parameters were deck reinforcement ratio, girder flange, and web thickness, while deck reinforcement yield stress was found to be insignificant. Based on the results, recommendations for improving blast resistance are provided. [ABSTRACT FROM AUTHOR]

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In recent years, the use of machine learning has been expanded to several fields, with promising advances in structural engineering applications. Deep neural network models have been implemented to predict the structural response of systems under conventional loading. Some of those neural network models are based on datasets containing images, test data, and/or data produced by using finite element models developed for a specific environment. While the accuracy of these models relies on the size and quality of the dataset, their use for blast analysis is rather limited, as publicly available data are scarce or restricted. Reinforced concrete (RC) walls or slabs under blast loading are commonly evaluated for flexural and shear behaviour, for which performance guidelines are widely available. While such response mechanisms are typically associated with the far-field range, the target response is controlled by local failure modes when blast loads are generated by contact or near-contact detonations. This paper introduces the implementation of a neural network model for the response prediction of RC walls subjected to contact and near-contact explosions. The model predicts the damage category (i.e., no damage, spall, and breach) associated with a given explosion scenario. The model is trained using experimental data from multiple test programmes available in open-source literature. It considers several parameters associated with the explosive charge (e.g., type, geometry, charge weight, and standoff) and RC target (e.g., material properties, geometry, and reinforcement). The model is able to accurately predict 81% of the total breached specimens, 66% of the total spalled specimens, and 71% of the full set of non-damaged specimens, with an overall accuracy of 72%, with precision and recall ranging from 60 to 76% and 66 to 81%, respectively. The current model is shown to be a significantly better predictor of the damage category than the semi-empirical approach outlined in UFC 3-340-02, making it a promising tool that can be improved with the inclusion of more experimental data. [ABSTRACT FROM AUTHOR]

This paper presents an optimization method for the design of marine metal sandwich plates to enhance the anti-blast performance of ship structures. The proposed method combines a neural network with the sparrow search algorithm to efficiently optimize the structure. The orthogonal design method is utilized to select appropriate sample points for the surrogate model. Dynamic responses of the ship under blast loading are obtained using the ABAQUS finite element software. By establishing an anti-blast surrogate model, the optimization problem is simplified. To overcome the limitations of the traditional backpropagation neural network, genetic algorithm and Adam algorithm are employed. Finally, the optimal solution is obtained based on the sparrow search algorithm. The results enable us to determine the structural dimensions with the best blast resistance. The proposed optimisation method can provide inspiration for improving the safety of ships. [ABSTRACT FROM AUTHOR]

A two-year field trial was conducted in order to assess techniques to control ginger blast and explore the effects of fumigants on soil bacterial microorganisms and ginger metabolites. This study examined the effects of dazomet and chloropicrin on the control of ginger blast and their influence on ginger yield in Luoping County, Yunnan Province, China. The results showed that in 2022, the control effectiveness of dazomet and chloropicrin treatments on ginger blast was 84.33% and 94.67%, respectively. The corresponding yields were 50,154.40 kg/hm2 and 50,296.90 kg/hm2. In 2023, the control effectiveness of dazomet and chloropicrin treatments on ginger blast were 86.33% and 93.67%, respectively, and the yields were 65,115.83 kg/hm2 and 65,337.93 kg/hm2. In both years, the incidence of ginger blast in the control group reached nearly 100%, leading to the near extinction of the crop. Additionally, in 2023, 16S rRNA high-throughput sequencing and non-targeted metabolomics techniques were used to analyze the effects of the fumigants on soil bacterial microorganisms and the metabolites in ginger. The results showed that the diversity and richness of soil bacterial communities were lower than those in the control group at 0 and 120 days after treatment with two fumigants, but the relative abundances of beneficial bacteria such as Pseudomonas increased at 60 days, and the relative abundances of Actinobacteria, Gemmatimonadetes, and Bacillus increased at 120 days. The abundance of Firmicutes also increased after 120 days of chloropicrin treatment. The non-targeted metabolic LC–MS results showed that the production of phenols and terpenoids was upregulated after dazomet and chloropicrin treatments. The contents of amino acids and their derivatives were also upregulated. This upregulation of metabolites was beneficial to the flavor quality of ginger and enhanced its anti-inflammatory, anti-tumoral, and antioxidant effects. [ABSTRACT FROM AUTHOR]

[Background] Intercropping is considered an effective approach to defending rice disease. [Objectives/Methods] This study aimed to explore the resistance mechanism of rice intraspecific intercropping by investigating soil metabolites and their regulation on the rhizosphere soil microbial community using metabolomic and microbiome analyses. [Results] The results showed that the panicle blast disease occurrence of the resistant variety Shanyou63 (SY63) and the susceptible variety Huangkenuo (HKN) were both decreased in the intercropping compared to monoculture. Notably, HKN in the intercropping system exhibited significantly decreased disease incidence and increased disease resistance-related enzyme protease activity. KEGG annotation from soil metabolomics analysis revealed that phenylalanine metabolic pathway, phenylalanine, tyrosine, and tryptophan biosynthesis pathway, and fructose and mannose metabolic pathway were the key pathways related to rice disease resistance. Soil microbiome analysis indicated that the bacterial genera Nocardioides, Marmoricola, Luedemannella, and Desulfomonile were significantly enriched in HKN after intercropping, while SY63 experienced a substantial accumulation of Ruminiclostridium and Cellulomonas. Omics-based correlation analysis highlighted that the community assembly of Cellulomonas and Desulfomonile significantly affected the content of the metabolites D-sorbitol, D-mannitol, quinic acid, which further proved that quinic acid had a significantly inhibitory effect on the mycelium growth of Magnaporthe oryzae, and these three metabolites had a significant blast control effect. The optimal rice blast-control efficiency on HKN was 51.72%, and Lijiangxintuanheigu (LTH) was 64.57%. [Conclusions] These findings provide a theoretical basis for rice varieties intercropping and sustainable rice production, emphasizing the novelty of the study in elucidating the underlying mechanisms of intercropping-mediated disease resistance. [ABSTRACT FROM AUTHOR]

Polyurea elastomers exhibit superior mechanical properties due to their unique molecular structure, including significant tensile strength, elongation at break, and efficient energy absorption. Many studies have shown that polyurea elastomers can effectively reduce structural damage caused by blast loads, thus attracting widespread attention in the field of blast protection. This review presents a comprehensive analysis of the formulation optimization, energy absorption mechanism and the close relationship between microstructure and macroscopic properties of polyurea elastomers. Additionally, recent research advances in the blast resistance of sprayed polyurea elastomers in various protective structures are summarized. Finally, this review summarizes the current challenges in polyurea elastomer research and provides a forward-looking perspective on its future development. Future research should prioritize the design of formulations and material optimization to systematically study the factors influencing the protective performance of polyurea composite structures. It should also explore the application of advanced technologies in polyurea research to investigate the protection mechanisms at the microlevel. [ABSTRACT FROM AUTHOR]

Based on numerical simulation software LSDYNA and field monitoring data, this paper analyzes the peak particle velocity (PPV) of rock mass at different distances from the blasting face of the roadway. At the same time, the dynamic stress concentration coefficient of surrounding rock under the action of different blasting times and the blasting damage effect of the tunnel are studied. The results show that in the tunnel blasting near the area, the PPV in the vertical direction of the tunnel is maximum in three directions; PPV decreases more slowly in the excavated zone than in the nonexcavated zone. When the explosion source is close to the roadway, the dynamic stress concentration coefficient of the blasting side and the rear side is large, so the vibration standard of surrounding rock should be strictly controlled. [ABSTRACT FROM AUTHOR]

In this study, the detonation behaviors of stoichiometric methane-hydrogen-oxygen (CH 4 –H 2 -2.5O 2) mixtures, diluted or not with carbon dioxide (CO 2), nitrogen (N 2) or helium (He), were investigated. By varying the initial pressure (p 0) or CO 2 , N 2 or He dilution concentration (0–60%), four modes of propagation could be clearly identified: stable detonation, fluctuation mode, galloping mode, and low-velocity mode. For each tested mixture, the detonation limit pressures for low-velocity mode were determined. It has been found that for given mixtures at higher dilutions, higher initial pressures are required to achieve steady mode with nitrogen dilution compared to helium dilution. As the initial pressure decreases and the dilution concentration increases, that will lead to the increase of the induction zone length and the more obvious influence of the pipeline boundary layer. This results in the increase of energy loss and velocity deficit during the propagation of detonation wave in the pipeline. As close to the critical limit pressures, there will be fluctuation, galloping and low-velocity detonation propagation modes. Depending on the type of the dilution gas as well as its concentration, the form of propagation mode at critical limit pressures will also be different. • The critical limit for different propagation modes for CH 4 –H 2 -2.5O 2 - diluted mixtures is analyzed. • Detonation velocity deficits for CH 4 –H 2 -2.5O 2 - diluted mixtures are determined. • The prediction formulas of CH 4 –H 2 -2.5O 2 - diluted mixtures between the induction zone length and initial pressure are performed. [ABSTRACT FROM AUTHOR]

The fragmentation size distribution is an important index to evaluate blasting effect. Based on stress wave theory, a blasting fragmentation distribution model is established, and the key influencing factors were clarified. Then, the distribution characteristics of rock fragmentation in water-coupled blasting and air-coupled blasting were compared and verified by numerical simulation and field test. The results show that the rock blasting fragmentation size is negatively correlated with borehole pressure and unit explosive consumption when blasting rock is determined. The existence of water slows down the attenuation of blasting load, prolongs the duration, and makes the blasting pressure transmitted to hole wall significantly greater than air-coupled one, which is equivalent to increasing the unit explosive consumption. Moreover, the rock fracture development speed and fragmentation degree of water-coupled blasting is significantly higher than air-coupled blasting. Comprehensively determined in same charging parameters, water-coupled blasting compared with air-coupled blasting can improve the degree of rock fragmentation, the average size of rock after blasting is smaller, more uniform particle size distribution. The research results for the control of blasting and optimization of explosive energy utilization have important reference significance. [ABSTRACT FROM AUTHOR]

Summary: A three‐dimensional refined numerical simulation model of a corrugated steel–concrete slab composite structure under contact explosion load was established by the finite element model and smoothed particle hydrodynamics(FEM‐SPH) coupling method to explore the anti‐knock properties of corrugated steel reinforced concrete slabs with different angles. The effects of corrugated steel angle on the dynamic response, damage evolution characteristics, damage mode, anti‐knock property, and propagation mechanism of the shock wave in the composite structure were investigated, and the damage prediction and anti‐knock property evaluation of the composite structure were carried out. The results show that the simulation results of the mid‐span displacement of the corrugated steel are consistent with the experimental results, and the maximum error is 2.3%, which verifies the effectiveness of the contact explosion simulation process. The mid‐span displacement, peak stress, acceleration at the center point, and energy absorption value of 90° corrugated steel are 17.9%, 70.5%, 88.6%, and 59.4% lower than those of 30° corrugated steel. The damage range of the composite structure gradually decreases with increasing angle of the corrugated steel. The failure volume of the concrete slab reinforced by corrugated steel with different angles decreases with increasing angle of the corrugated steel, and the energy absorption value of the composite structure increases with increasing of angle of the corrugated steel, mainly because the corrugated steel increases the number of reflections of the stress wave. The research results can provide a theoretical basis for the application of composite structures in the field of structural anti‐explosion protection. [ABSTRACT FROM AUTHOR]

Due to the high energy absorption capability and excellent bending strength of the sandwich panels, they are mostly preferred as protective structures against explosive blast attacks. The evaluation of their blast-mitigation characteristics through experiments is highly dangerous, costly, time-consuming, and polluting for the environment. Therefore, in this presented work, a series of numerical analyses were performed to evaluate the blast mitigation of the outstanding sandwich panels with honeycomb, corrugated, auxetic, and foam cores. The masses of sandwich panels were kept constant, and their areal densities were maintained constant throughout the study to effectively compare their performance under identical air blast loading conditions. To apply the air blast loads to the designed sandwiches, 1–3kg of spherical-shaped trinitrotoluene charges were used for a 100mm stand-off distance. The sandwiches are made of high-strength AL-6XN steel and crushable aluminum foam. The rate-dependent Johnson–Cook constitutive model of plasticity and the crushable foam model with volumetric hardening were used for the evaluation of sandwich panels’ plastic deformations. The findings of the work depicted that the honeycomb core is more efficient than the other core structures of the same masses because the sandwich panels with honeycomb core provide smaller back skin deflections, globalized core crushing, and higher core energy absorption than the other sandwich panels for extreme conditions of air blast loading. [ABSTRACT FROM AUTHOR]

To investigate the dynamic mechanical response and damage mechanisms of I‐shaped steel‐concrete composite beams under explosive loads, experimental research and numerical simulations were conducted on steel‐concrete composite structures. The accuracy of the numerical analysis model was validated by comparing the damage characteristics of the structures obtained from explosive tests on the steel‐concrete composite components. Based on this, numerical simulations were performed on steel‐concrete composite beams using the explicit dynamic analysis software ANSYS/LS‐DYNA, and a study on their damage mechanisms was conducted. This study resulted in the acquisition of dynamic mechanical response patterns, including time‐dependent stress, strain, displacement, acceleration, and so on. Different structural damage characteristics under various explosive conditions were summarized, and key parameters affecting the blast resistance of the structure were analyzed. The research findings indicated that, in contrast to the failure characteristics of I‐shaped reinforced concrete (RC) beams, the failure characteristics of I‐shaped steel‐concrete composite beams mainly include punching and shearing failure of the steel‐RC slab and local buckling of the steel beam. Under the same explosive conditions, steel‐concrete composite structures exhibit superior blast resistance, with certain changes in structural parameters significantly improving blast resistance. The research results can provide theoretical support and a scientific basis for the proactive design of blast protection in steel‐concrete beams. [ABSTRACT FROM AUTHOR]