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With the increasing number and scale of buried natural gas pipelines, accidents resulting from gas leaks into adjacent underground spaces, which can lead to gas explosions, have become increasingly prevalent. Currently, the transportation of hydrogen blended with natural gas is emerging as the most economical method for long-distance hydrogen delivery. However, blending hydrogen with natural gas significantly increases the explosion hazard of the resulting mixture. In this paper, a computational fluid dynamics (CFD) numerical simulation method is used to establish the leakage and diffusion model of hydrogen-blended natural gas (HBNG) pipeline in soil-brick gutter coupling space. The concentration diffusion trends of HBNG within this coupling space are examined, alongside the effects of the hydrogen blending ratio (HBR), leakage aperture, pipeline pressure, leakage location and leakage direction on the leakage and diffusion processes. The results indicate that an increased HBR prolongs the hazardous presence of HBNG in the brick gutter. A larger leakage aperture and higher pipeline pressure lead to a higher leakage rate and faster diffusion of HBNG. Conversely, small leakage aperture and lower pressure conditions extend the duration for which the gas concentration remains within the flammability limit. When the leakage points are located inside the brick gutter, the HBNG rapidly fills the gutter upon leakage. The direction of the leakage affects the distance the HBNG will spray, after which it will diffuse into the ground and deeper soil under the influence of buoyancy and gravity. Finally, a regression-based formula for calculating the leakage rate of buried HBNG pipeline is derived by fitting the simulation data, providing valuable references for pipeline operation and maintenance. • Numerical simulation of hydrogen-blended natural gas leakage and diffusion. • The concentration distribution under different leakage conditions is studied. • Dangerous times inside the brick gutter space are obtained. • Factors affecting leakage and diffusion are analyzed. • The leakage rate calculation model of buried pipeline is established. [ABSTRACT FROM AUTHOR]

Hydrogen energy is essential for improving environmental issues and developing sustainability. It is important to investigate the kinetic mechanism of hydrogen explosion suppression to clarify the prevention and control of hydrogen explosion disasters. A 20L spherical explosion test equipment is used to conduct suppression experiments of hydrogen-air mixture explosions with various inert gases. The evolution of flame behaviour and explosion pressure in the container is recorded, respectively. The microscopic suppression mechanism of different inert gases in the H 2 -air premixed gas explosion is revealed by comparing the inhibition effects and analyzing the macroscopic physical parameters characteristics of the hydrogen explosion under a diluted environment. The findings indicate that the hydrogen explosion reaction rate reduces as the concentration of inert gas increases and that the flame propagation radius, maximum explosion pressure, and maximum pressure rise rate all drop linearly. The same proportion of gas diluent has different suppression effects on H 2 explosion. CO 2 /N 2 not only mitigates hydrogen explosion at the physical level but also affects the changes of free radicals through chemical competition. CO 2 has the most significant restriction on various explosion characteristic parameters and flame propagation, followed by He and N 2. The research results support the safe application of hydrogen energy. • Effect of CO 2 , He and N 2 on hydrogen/air explosion behaviour were experimentally investigated. • Inerting effect of different inert gases were assessed using four evaluation parameters. • CO 2 had a better inhibiting effect on hydrogen/air explosion than He and N 2. • Greater proportions of CO 2 in the diluent significantly affected flame structure and explosion pressure. • The microscopic mechanism of inert gases on hydrogen/air explosion were revealed. [ABSTRACT FROM AUTHOR]

Integrating hydrogen into sustainable energy systems and existing natural gas infrastructures requires fast and reliable prediction of blast dynamics of hydrogen-methane-air mixtures to design effective protective structures. This study proposed an analytical model for predicting blast loading from hydrogen-methane-air (H 2 –CH 4 -air) explosions in unconfined spaces, with or without obstacles. The model includes a flame speed prediction formula that accounts for fuel-air characteristics, congestion levels, and fuel quantities, based on extensive experimental data. Modified open-source codes were utilized to calculate the laminar flame properties for the flame speed prediction formula under various initial temperatures, H 2 /CH 4 ratios, and equivalence ratios. Additionally, an empirical model based on theoretical calculations was devised for rapid computation of laminar flame properties. This flame speed prediction formula integrated into the blast loading prediction framework was validated by comparing predicted peak pressures and impulses against diverse experimental results, including scenarios with CH 4 -air, H 2 -air, and CH 4 –H 2 -air mixtures, both with and without congestion. The application of this model was demonstrated through a case study at Australia's first commercial hydrogen refueling station and another case study for the development of engineering chart for rapid blast loading estimation, illustrating its practical utility in blast loading determination. This research provides an efficient tool for predicting H 2 –CH 4 -air blast loading, offering a systematic approach to assess and mitigate the risks associated with vapor cloud explosions in unconfined industrial settings. • Developed a fast and reliable blast loading model for H 2 –CH 4 -air mixtures, validated with experiments. • Proposed an empirical formula to predict laminar flame properties for H 2 , CH 4 , and blends. • Demonstrated practical uses, including blast prediction at hydrogen refueling stations and engineering chart development. [ABSTRACT FROM AUTHOR]

The application of machine learning (ML) for the prediction of gas explosion pressure remains limited, and the prediction of the explosion duration is nearly non‐existent. A series of dispersion and subsequent explosion computational fluid dynamics (CFD) simulations were conducted to determine explosion pressure and duration values. These results were used to train classical ML models, that is, support vector regression (SVR), random forest (RF), and decision tree (DT) models. Additionally, a multi‐output Adam‐optimized artificial neural network (ANN) model was employed for performance comparison. All the models demonstrated respectable predictions for both parameters, while the RF model demonstrated the highest performance based on the metrics analyzed, followed by the DT model. The proposed gas volume and gas volume blockage ratio (gas‐VBR) emerged as the most crucial feature for predicting explosion pressure, while the monitoring point and gas‐VBR was the most important feature for explosion duration. It is recommended to consider the gas‐VBR feature in future studies rather than solely focusing on blockage ratio or obstacle location. The model proposed was compared with models from previous studies for predicting explosion pressure. The findings conclusively demonstrate that the multi‐output model outperforms the compared models, offering a notable advantage in its ability to predict both gas explosion pressure and duration. [ABSTRACT FROM AUTHOR]

Indoor hydrogen-blended natural gas (HBNG) leakage may lead to more serious explosions, so the aim of this study was to analyze the consequences of HBNG explosions inside residential building. In this study, a numerical model of hydrogen-blended gas explosion in a residential building was developed using FLACS software. The accuracy of the model was verified by comparing it with the actual experimental data. The numerical simulations were performed for different, kitchen structures, ignition positions, equivalence ratios (ERs) and hydrogen blending ratios (HBRs). The results show that the change in blast overpressure depends on the combined effect of the time of breaching the door or window and the rate of combustion. Besides, the time to reach the peak explosion pressure and explosion duration are negatively correlated with the ER, the peak pressure generated by the explosion and the range of the distribution of the explosion temperature are positive correlation with the ER. Furthermore, the results suggest that the mix of hydrogen and natural gas increases the peak explosion pressure and the accelerates flame propagation, which however also shortens the time to peak explosion pressure and the duration of the explosion. It can provide a theoretical basis for the adoption of HBNG explosion protection measures in residential buildings in the future. [Display omitted] • Numerical simulation of an explosion in a residential building. • Analysing the consequences of an explosion under four influencing factors. • Factors affecting changes in blast overpressure were analysed. • Reasons affecting the shape of the flame were analyzed. [ABSTRACT FROM AUTHOR]

In order to study the flame retardant performance of corrugated flame arrester core on the explosion characteristics of 9.5% hydrogen/methane/air premixed gas, a self-built experimental platform was used to study the explosive characteristics and propagation rules and the impact of varying thicknesses and different volumes of hydrogen. The results indicated that the corrugated flame arrester core on the explosion flame of premixed gas was observed with two scenarios, quenching and penetration. The flame is dominated by reverse vortex flow after quenching, reversing the axial direction of flame propagation. However, the flame penetration leads to more intense burning reactions as φ increases. And the increase in thickness changes the flame structure forms a spherical flame to a mushroom-shaped flame and finally form a turbulent flame. The velocity of flame decreased significantly when L = 60 mm with φ = 10% and 20% respectively. The quenching effect is more obvious in P2 with hydrogen added, and its better performance with increasing thickness, with 9.76% and 3.70% decrease when L = 40 mm with φ = 10% and 20%, respectively, and with 57.05% and 48.55% decrease when L = 60 mm with φ = 10% and 20%, respectively. [ABSTRACT FROM AUTHOR]

The safe operation of natural gas stations as complex and dense equipment sites after the mixed transportation of hydrogen will face great challenges. Predicting accident consequences is of importance for emergency rescue. In this work, the evolution law in the accident scenarios of hydrogen-blended natural gas stations was investigated through a computational fluid dynamics (CFD) model. The results suggest that the mix of hydrogen and natural gas increases the explosion intensity of combustible gas clouds, which however also accelerates the diffusion rate of leaked gas into air. Therefore, the peak explosion overpressure fails to show a simple linear relationship with the hydrogen blending ratio in different hydrogen blending ratio scenarios. The worst accident consequences occur in Scenario 2 (hydrogen blending ratio = 20%), where the blast overpressure peak reaches 19.29 kPa. Wind can accelerate the material transmission speed of leaked gas in space. In scenarios with larger wind speeds, the hazard degree of accidents can be significantly reduced. [ABSTRACT FROM AUTHOR]

A large number of gas explosion accidents have shown that secondary explosions are more dangerous and destructive than the primary. Based on the self-designed sliding experiment platform, the influence of sliding device on the evolution behavior of fuel enriched and lean flame fronts be compared. The study shown that adjusting the initial sliding position of porous media to 40 cm and using an appropriate spring coefficient can effectively extinguish methane flame in both fuel enriched and fuel lean combustion states. This method can reduce the range of flame diffusion, burning time and intensity compared with using fixed porous media, and also the maximum explosion overpressure. When using a sliding device in methane lean combustion, it can achieve significant reductions in the duration of the reverse diffusion flame (up to 64.02%), the quenching time of the flame (up to 44.21%), and the explosion overpressure inside the tube (up to 24.2%). During rich methane combustion, using sliding device can result in a reduction of up to 62.26% in the duration of the reverse diffusion flame, up to 46.81% in the quenching time of the flame, and up to 44.12% in the explosion overpressure inside the tube. Additionally, the inhibitory effect of the sliding device and the increase in elastic coefficient follow a pattern of initially increasing and then decreasing. In general, the sliding device is more effective in suppressing methane flames and overpressure during both enriched and lean fuel combustion than fixed device. The results can provide valuable insights for the development of secondary explosion prevention technology, which is crucial for preventing and managing methane explosion accidents. [ABSTRACT FROM AUTHOR]

To elucidate the mechanism of lateral relief conduits in combustible gas pipelines, this study proposes an experimental pipeline system equipped with a sidewall conduit. Furthermore, the research utilizes the standard two‐dimensional k‐ε model in conjunction with the Zimont combustion model for numerical simulation. Four different configurations were investigated by varying the position and the number of lateral explosion relief conduits. This paper mainly analyzes the impact of lateral conduits on the propagation of flames, overpressure, and flow fields within the pipeline during an explosion. The results indicate that the combined effect of the horizontal force from the main pipe's end relief and the longitudinal force within the lateral explosion relief conduit creates an acute angle between the flow directions in the lateral conduit and the adjacent main pipe. The branch pipe near the ignition end of the main pipeline has a significant effect on restricting flame propagation. Additionally, the two lateral explosion relief conduits facilitate pressure relief more efficiently. It was also found that relief ports upstream of the flame front inhibit flame propagation, while those downstream may induce it. [ABSTRACT FROM AUTHOR]

Considering the uncertainty and fuzziness of the risk assessment index of coal mine gas explosion, a risk assessment model of gas explosion based on combinatorial weighting‐unascertained measure of safety information loss is proposed. First, 20 risk indicators are extracted from the six aspects of supply loss, transformation loss, transmission loss, perceived loss, cognition loss, and response loss in the process of safety information flow. The weight vector is constructed by the G1 method and anti‐entropy weight combination weighting method. Then, the single‐index measurement function is used to process the risk index measure. Based on the classification standard of the gas explosion risk assessment index, the single‐index and multi‐index measurement matrices are constructed. And the grade is judged according to the principle of maximum membership. Finally, a mine is selected for case application. The results show that the evaluation results are consistent with the actual situation and the method has certain feasibility. It provides a new idea and method for advanced control and accident prevention of coal mine gas explosion risk. [ABSTRACT FROM AUTHOR]

As unconventional building structures, container houses are now widely used in urban tourism to create characteristic buildings. Nowadays, natural gas accidents occur frequently in cities and towns; however, the development of laws and influencing factors of natural gas accidents in container buildings have rarely been studied. In this paper, a natural gas explosion test was carried out in an ordinary container house, and a numerical simulation was carried out according to the test results. The influence of methane proportion, ignition position, pressure-relief area, and pressure-relief intensity on the explosion load was analyzed. Research shows that natural gas will gather from top to bottom during the process of leakage and diffusion, and vertical stratification will occur. The most unfavorable working condition is 9.5% methane. Using the roof of the container house as a pressure-relief panel can effectively control the influence range of natural gas explosion accidents and help reduce accident losses. It is suggested that the stacking of container buildings should be reduced as much as possible, and the roof strength should be weakened to ensure structural safety. The research results have certain reference values for the disaster prevention and reduction design of urban characteristic buildings. [ABSTRACT FROM AUTHOR]

To study the influence of obstacles on the premixed gas explosion process and provide a theoretical basis for the safe use of fuel and the space configuration within weakly constrained structures, experimental and numerical simulation studies were conducted to investigate the explosion behavior of H2/CH4 premixed gas under different obstacle conditions. According to the angle and position of obstacles, 12 explosion working conditions were set up, and the flame kinetic behavior under the combined influence was obtained. The results show that increasing the direct contact area between the obstacle and the flame near the ignition source can effectively reduce the explosion effect. The explosion consequence is most serious when the obstacle is located in the middle position of the weakly constrained structure. When the obstacle is close to the vent, the later the flame reaches the vent, the more the explosion pressure peaks, and the explosion impact decreases as the angle of the obstacle decreases. In the numerical simulation, it was also found that when the flame passes through the obstacle near the ignition source, it takes on a special "jellyfish" shape toward the vent. In conclusion, the results of the study are useful for making reasonable assumptions about the location of the ignition source and the presence of obstacles based on the degree of damage to the weakly confined structure caused by the premixed gas explosion. [ABSTRACT FROM AUTHOR]

The advances in research on the explosion load characteristics of the fuel–air mixture in vented chambers are reviewed herein. The vented explosion loads are classified into three typical types based on this comprehensive literature research. These models are the accumulation load model, attenuation load model, and interval jump load model. The characteristics of the three different typical vented explosion load models are analyzed using Fluidy-Ventex. The research results show that overpressure is largely determined by methane concentrations and vented pressure. The turbulent strength increased from the original 0.0001 J/kg to 1.73 J/kg, which was an increase of 17,300 times, after venting in the case of a 10.5 v/v methane concentration and 0.3 kPa vented pressure. When the vented pressure increased to 7.3 kPa, the turbulent strength increased to 62.2 J/kg, and the overpressure peak correspondingly increased from 69 kPa to 125 kPa. In the case of the interval jump load model, the explosion overpressure peak tends to ascend when the intensity of the fluid disturbance rises due to the venting pressure increasing at a constant initial gas concentration. When the venting pressure reaches tens of kPa, the pressure differential increases sharply on both sides of the relief port, and a large amount of combustible gas is released. Therefore, there is an insufficient amount of indoor combustible gas, severe combustion is difficult to maintain, and the explosion load mode becomes the attenuation load model. [ABSTRACT FROM AUTHOR]

Background: Dysbiosis of gut microbiota (GM) is intricately linked with cognitive impairment and the incidence of traumatic brain injury (TBI) in both animal models and human subjects. However, there is limited understanding of the impact and mechanisms of fecal microbiota transplantation (FMT) on brain and gut barrier function in the treatment of TBI induced by gas explosion (GE). Methods: We have employed FMT technology to establish models of gut microbiota dysbiosis in male rats, and subsequently conducted non-targeted metabolomics and microbiota diversity analysis to explore the bacteria with potential functional roles. Results: Hematoxylin–eosin and transmission electron microscopy revealed that GE induced significant pathological damage and inflammation responses, as well as varying degrees of mitochondrial impairment in neuronal cells in the brains of rats, which was associated with cognitive decline. Furthermore, GE markedly elevated the levels of regulatory T cell (Tregs)-related factors interleukin-10, programmed death 1, and fork head box protein P3 in the brains of rats. Similar changes in these indicators were also observed in the colon; however, these alterations were reversed upon transfer of normal flora into the GE-exposed rats. Combined microbiome and metabolome analysis indicated up-regulation of Clostridium_T and Allobaculum , along with activation of fatty acid biosynthesis after FMT. Correlation network analysis indirectly suggested a causal relationship between FMT and alleviation of GE-induced TBI. FMT improved intestinal structure and up-regulated expression of tight junction proteins Claudin-1, Occludin, and ZO-1, potentially contributing to its protective effects on both brain and gut. Conclusion: Transplantation of gut microbiota from healthy rats significantly enhanced cognitive function in male rats with traumatic brain injury caused by a gas explosion, through the modulation of gut microbiome composition and the improvement of both gut and brain barrier integrity via the gut-brain axis. These findings may offer a scientific foundation for potential clinical interventions targeting gas explosion-induced TBI using FMT. [ABSTRACT FROM AUTHOR]

The application of industrial solid waste coal gangue (CG) in gas explosion suppression is explored, which opens up a new way for the resource utilization of CG. Two modified CG anti‐explosion agents, first‐grade modified CG (RCG) and second‐grade modified CG (MCG), were prepared by roasting activation and acid–base synergistic excitation. The explosion suppression performance of CG, RCG, and MCG was investigated through a 2.5 L semi‐closed explosion pipe. The experimental results were compared and analyzed, and their pyrolysis characteristics, phase composition, and particle size were analyzed to reveal their explosion suppression mechanism. It was proved that MCG had the best explosion suppression effect. Under the condition of 9.5% methane–air, it was found that the explosion suppression effect was most significant when the powder mass of the three powders was 300, 360, and 360 mg, respectively. The peak explosion overpressure is reduced by 10.51%, 21.96%, and 32.66%, respectively, and the peak arrival time of flame velocity is extended by.14 times,.20 times, and 1.15 times, respectively. MCG can effectively inhibit methane explosion utilizing physical and chemical synergistic heat absorption, porous structure formation barrier, heat isolation, oxygen dilution, adsorption, and capture of free radicals. [ABSTRACT FROM AUTHOR]

To further investigate the propagation characteristics of shock waves and flame waves in H‐type tunnel gas explosions, numerical simulation studies were conducted on a dual‐source gas explosion model using Fluent software. Three distinct operational conditions were designed and modeled, leading to the following outcomes. The shock wave flow field parameters from dual sources (with equal source energy) are symmetrically distributed in the H‐type tunnel, with high pressure and low flow velocity in the connecting roadway between the two shock waves. Under different conditions, the pressure is generally higher in closed tunnels (fully closed greater than semi‐closed) and lower in open tunnels. The largest overpressure in non‐explosion areas occurs at the closed ends and in the connecting roadway, while the areas bearing the greatest impulse are the shock wave reflection zones and pressure coupling regions. In closed conditions, the flame wave first moves forward and then propagates backward after the explosion, influenced by reflected waves and pressure differences between the ends and the tunnel. In open conditions, the pressure in the flame zone is lower than at both ends, inhibiting the forward propagation of the flame wave. [ABSTRACT FROM AUTHOR]

The blast pressure acting on the borehole wall is the basis of the dynamic analysis of rock blasting. The history of blast-induced borehole wall pressure (BWP) is difficult to measure owing to the complex interaction between the blasting load and the borehole wall, and the limitations of the general test system. In this work, the complete history of BWP under air-deck charge was measured for the first time, and the stress-response process was analyzed. PVDF (polyvinylidene fluoride) gages and a charge mode for the test circuit were employed. To improve the testing accuracy, the matching relationships among the parallel capacitor, the equivalent capacitance of PVDF gages, and the parasitic capacitance of the coaxial cable were effectively addressed. The experimental data within the span of 0–0.65 m from the explosive cartridge center show that there are two obvious peaks in the complete history of BWP, the first is a μs-level air shockwave load, followed by a ms-level explosion gas load. The peak of BWP is dominated by the peak of explosion gas (Pg) within the scope of about 0–0.35 m from the explosive cartridge center, while is mainly determined by the peak of air shockwave (Ps) in a farther range. The specific impulse distribution suggests that the explosion energy is mainly consumed in the area within the range of about 0–0.25 m from the explosive cartridge center. The strain rate in the borehole wall induced by air shockwave demonstrates a dynamic response (range of 131.9 ~ 2922.6 s−1), while indicating a quasi-dynamic loading (range of 0.1 ~ 2.1 s−1) when induced by the explosion gas. The findings contribute to expanding the understanding of the stress characteristics of the air shock wave and explosion gas and provide accurate initial loads for numerical simulation related to rock blasting of non-fluid–solid coupling. Highlights: The complete history of borehole wall pressure under air-deck charge was accurately measured by solving the capacitance matching in the test circuit for charge mode. The entire stress response process of the borehole wall rock is revealed. The specific impulse distribution of air shock wave and explosion gas along the borehole axis is obtained. The stress characteristics of borehole wall induced by air shockwave and explosion gas are compared. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology 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 investigated the deflagration and detonation suppression effect by different thicknesses of metal foam. The results show that the gas explosion suppression effect of metal foam is related to the explosion stage and the metal foam thickness. In the deflagration stage, the flame could be quenched by 10 mm, 20 mm, and 30 mm thick metal foam. In the flame acceleration stage, the flame can only be quenched by the 30 mm thick metal foam. In the detonation stage, detonation could be completely quenched by 20 mm or 30 mm thick metal foam. Ten-millimeter-thick metal foam could make detonation stage convert into deflagration stage and overpressure decreases obviously. Different propagation mechanisms of deflagration and detonation lead to different suppression effects of foam metal. [ABSTRACT FROM AUTHOR]

This work aims to investigate the effect of N2/CO2 on the explosion behavior of premixed liquefied petroleum gas (LPG)-air in a half-open duct. Experiments were performed in a duct (L/D = 47.5) with the ignition end closed and the other end open. Firstly, the optimal explosion concentration of LPG was determined using the stepwise approximation method, secondly, the effects of different volume fractions (VFs) of N2/CO2 on the pressure dynamic process, flame propagation velocity, and explosion severity of LPG-air explosion were analyzed, and finally the inerting effects of N2 and CO2 were compared using the control variable method. The results show that the explosion pressure and flame propagation velocity reach a maximum when the VF of LPG is 4.8% (without inert gas), and two pressure peaks (the first pressure peak (P1) and the second pressure peak (P2)) are observed. When the VF of LPG is 4.8%, the maximum pressure and the average flame propagation velocity in the tube decrease and the explosion intensity inside and outside the duct was effectively mitigated as the VF of N2/CO2 increases, and the explosion is completely suppressed as the VF of inert gas reached 30%. P2 is significantly suppressed, and the maximum explosion pressure (Pmax) occurs at $${P_1}$$ P 1 when the VF of N2/CO2 is above 15%. The suppression effects of CO2 are more remarkable at a lower VF (below 18%), those of N2 are more significant at a higher VF (above 18%), and P1 also follows this rule. For a given volume fraction of inert gas, the suppression effect of N2/CO2 on the degree of explosion severity becomes more significant when approaching the optimal LPG explosion concentration (4.8%). [ABSTRACT FROM AUTHOR]

Military personnel, firefighters, and fire survivors exhibit a higher prevalence of mental health conditions such as depression and post‐traumatic stress disorder (PTSD) compared to the general population. While numerous studies have examined the neurological impacts of physical trauma and psychological stress, research on acute neurobehavioral effects of gas inhalation from explosions or fires is limited. This study investigates the early‐stage neurobehavioral and neuronal consequences of acute explosion gas inhalation in Sprague–Dawley rats. Rats were exposed to simulated explosive gas and subsequently assessed using behavioral tests and neurobiological analyses. The high‐dose exposure group demonstrated significant depression‐like behaviors, including reduced mobility and exploration. However, neuronal damage was not evident in histological analyses. Immunofluorescence revealed increased density of radial glia and oligodendrocytes in specific brain regions, suggesting hypoxia and axon damage induced by gas inhalation as a potential mechanism for the observed neurobehavioral changes. These findings underscore the acute impact of explosion gas inhalation on mental health, highlighting the habenula and dentate gyrus of hippocampus as the possible target regions. The findings are expected to support early diagnosis and treatment strategies for brain injuries caused by explosion gas, offering insights into early intervention for depression and PTSD in affected populations. [ABSTRACT FROM AUTHOR]

In order to investigate the propagation characteristics of natural gas explosions by ignition position in complex pipelines, a series of ignition positions were set up in an H-type pipeline for simulation using commercially available software. The findings of the study indicated that in the H-type pipeline contact pipe, the flame structure array develops with the greatest rapidity and the most violent shock wave propagation speed. The shock wave generated by the natural gas explosion is reflected and superimposed on multiple occasions when it encounters the pipeline wall, and it exhibits fluctuations and an increase in amplitude during propagation. In this process, the pressure peak is typically situated in closer proximity to the closed end of the pipeline, in comparison with the contact pipeline. The overpressure peak of the main pipeline was also observed to be higher. By comparing the rate of pressure rise at varying ignition locations and integrating this with the explosion hazard factor, it can be determined that the closer the ignition point, the greater the associated hazard. Consequently, the closed end of the pipeline was observed to experience a more significant degree of explosion hazard. [ABSTRACT FROM AUTHOR]

To explore the combustion characteristics of ammonia‒hydrogen‒air flame, explosion venting experiments of ammonia‒hydrogen‒air mixtures with different equivalence ratios (ϕ), in the range of 0.6–1.7, are carried out in a 2 m long duct. The results show that the pressure‒time histories inside the duct have a three-peak structure (P b , P out , and P ext), which is caused by the burst of the vent cover, venting of burned mixtures, and counterflow flame generated by the external explosion, respectively. P out evolves into three pressure peak types with increasing ϕ. The pressure peak value P e is generated at the pressure measuring point outside the duct because of the external explosion. The change in P e with ϕ is consistent with P out and P ext , all of which increase first and then decrease with increasing ϕ and reach a maximum value at ϕ = 1.3. This study provides basic theoretical support for the promotion and application of ammonia mixed fuel. • The effects of the equivalence ratio, ϕ , on duct-vented ammonia‒hydrogen‒air deflagration were studied. • Counterflow flame generated by the external explosion was observed in all experiments. • The pressure‒time histories inside the duct under each operating condition present had a three-peak structure. • The maximum overpressure inside and outside duct first increased and thereafter decreased. [ABSTRACT FROM AUTHOR]

To study the flame propagating characteristic and its coupling effect with other parameters in the LPG pipeline, a typical pipeline model with two equal‐length branches perpendicular to each other is designed for experiment and simulation. Then, gas explosion scenarios are experimentally tested and numerically simulated, which is followed by the analysis of flame shape changing with time and peak temperature changing with space. Results show that when passing through the bifurcation, flame propagates to vertical branch B in a sharp knife shape affected by the strong vortex, reflected airflow, and compressed pressure wave in the pipeline with a diameter of 0.125 m. At the monitoring point that is 0.4 m away from the bifurcation point, the peak temperature of the vertical branch B is 57.87% bigger than that of the horizontal branch C, and its arrival time is 80% longer than that of the horizontal branch C, due to the existence of flame in vertical branch B. What's more, in both branches, the coupling results between peak temperature and peak velocity agree very well with the growth function, while the coupling results between peak temperature and peak pressure agree well with the decay function, providing aids to the optimal layout design of industrial pipeline branches as well as to the explosion suppression measures. [ABSTRACT FROM AUTHOR]

Combustible gases, such as CO, CH4, and H2, are produced during spontaneous coal combustion in goaf, which may cause an explosion under the stimulation of an external fire source. It is of great significance to study the influence of combustible gases, such as CO and H2, on the characteristics of a gas explosion. In this study, CHEMKIN software (Version 17.0) and the GRI-Mech 3.0 reaction mechanism were used to study the influences of different concentration ratios between CO and H2 on the ignition delay time, free radical concentration, and key reaction step of a gas explosion. The results show that the increase in the initial CH4 and CO concentrations prolonged the ignition delay time, while the increase in the H2 concentration shortened the time and accelerated the explosion reaction. The addition of H2 promoted the generation of free radicals (H·, O·, ·OH) and accelerated the occurrence of the gas explosion. CO generated ·OH free radicals and dominated the methane consumption through the R119 and R156 reactions. As the concentrations of CO and H2 increased, the R38 reaction gradually became the main driving factor of the gas explosion. [ABSTRACT FROM AUTHOR]

Coke oven gas (COG), as a by-product of the coking process and a mixture with a high hydrogen content, is an important potential component of the sustainable economy of the coking industry. Ongoing studies and analyses are looking at many opportunities for the utilization of coke oven gas, including for the production of hydrogen, methanol or other chemicals. However, it is important not to forget that all processes for the utilization of this gas may pose a potential hazard to humans and the environment. This is due to the physicochemical properties of COG and the content of flammable gases such as hydrogen, methane or carbon monoxide in its composition. Potential hazardous events are also related to the content of toxic substances in the composition of coke oven gas. The publication focuses on the occurrence of a fire or explosion as a result of the uncontrolled release of purified coke oven gas from the installation. The potential hazard zones associated with the occurrence of these phenomena are presented concerning different levels of hydrogen concentration in coke oven gas and the influence of selected factors on the range of these zones. Zones related to human deaths due to fire of coke oven gas reached a maximum range of about 130 m from the site of the failure, depending on the gas composition, level of damage and parameters of the installation. Zones related to human deaths due to the explosion of the coke oven gas did not occur. The zone related to the injury of humans as a result of the COG explosion reached a maximum range of about 12 m. [ABSTRACT FROM AUTHOR]

Rampart craters are a class of lakes or depressions in Titan's north polar region that have morphological attributes suggestive of an explosive origin. Two previous studies have proposed that rampart craters form via nitrogen or methane vapor explosions analogous to terrestrial maar explosions. We propose a new terrestrial analog for rampart craters: gas emission craters (GECs) found in permafrost zones. We evaluate the explosive origin of Titan's rampart craters by modeling the dispersal of material from an explosive vent. The dimensions of nine rampart craters with radar‐bright ramparts were used to model the explosion process. The model yields a range of explosion conditions (e.g., gas mass and reservoir depth) producing ejecta dispersal patterns matching the observed features. We find that gas masses of 1011–1014 kg are required to produce a rampart crater. We examine two explosion scenarios: (a) rapid, maar‐like vaporization and explosion of liquid nitrogen or methane, and (b) more gradual gas accumulation and explosion akin to a GEC driven by methane released from destabilizing clathrates. If Titan's crust is composed of pure water ice, the calculated gas pressures are consistent with a rapid, maar‐like explosion mechanism. If the subsurface is predominantly composed of organic materials or clathrate, either scenario may be plausible. Further research on the composition and tensile strength of Titan's subsurface are required to discriminate between hypotheses. Nevertheless, we conclude that explosive dispersal of ejecta from a vent can account for the morphologies of Titan's rampart craters and may contribute to atmospheric methane replenishment. Plain Language Summary: Rampart craters are lakes, filled or empty, in Titan's north polar region that appear to have formed via explosions. In this study, we use a numerical model and Cassini data to determine whether explosive release of subsurface pressurized gas can form rampart craters, and estimate the amount of gas required. We find that gas explosions sourced from the vaporization of liquid nitrogen or methane, or from methane released from within the ice crystal structure of methane clathrate, are capable of reproducing the observed shapes and dimensions of rampart craters. Large amounts of methane can be released in such explosions, replenishing Titan's diminishing atmospheric methane. Key Points: Explosive release of pressurized gas can form Titan's rampart cratersWe model maar‐like explosions driven by vaporization and gas emission crater‐like explosions driven by destabilized methane clathratesSignificant amounts of methane gas can be delivered to the atmosphere during the formation of a rampart crater [ABSTRACT FROM AUTHOR]

Copyright of Journal of Beijing University of Civil Engineering & Architecture is the property of Journal of Beijing University of Civil Engineering & Architecture 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.)

Copyright of China Mining Magazine is the property of China Mining Magazine Co., Ltd. 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.)

Gas explosions mostly occur in turbulent environments in practical situations. Meanwhile, the current research on the explosion characteristics of hydrogen-doped natural gas is mostly methane/hydrogen mixed fuel, ignoring the influence of other components of natural gas on the explosion characteristics of the actual situation. Therefore, the effects of different jet intensities (P jet), hydrogen-doping ratios (X H2) and equivalence ratios (φ) on the explosion characteristics of multi-component natural gas/hydrogen mixed fuel are experimentally investigated in cylindrical tanks of 30 L. Additionally, it extensively explored the dual influence of jet disturbance and gas inerting effect on the flame propagation characteristics of multi-component natural gas/hydrogen mixed fuel. With the increase of P jet , both P max and (d p/ d t) max initially increase and then decrease, while τ continuously decreases. When P jet = 0.4 MPa, the promotion effect on P max and (d p/ d t) max is most significant. The lifting of X H2 leads to a gradual increase in P max and decreasing τ. (d p/ d t) max exhibits a trend of initially increasing and then decreasing with the elevation of X H2 , reaching its maximum at X H2 = 40%. The introduction of jet flow significantly reduces the promotion or inhibition effect on explosions of high hydrogen blending ratio mixtures. Furthermore, the introduction of jet flow is more effective in promoting the explosive performance of multi-component natural gas/hydrogen mixed fuel with high equivalence ratios and low hydrogen doping ratios under rich fuel conditions. This study can provide a key reference for the explosion hazard assessment during the practical application of natural gas/hydrogen mixed fuel. • Hydrogen-doped natural gas is used in explosion experiments collected in real environments. • A gas jet disturbance experimental platform has been established. • The flame propagation characteristics under turbulent conditions have been summarized. • The promotion effect on the explosion is most significant when the jet intensity reaches 0.4 MPa. [ABSTRACT FROM AUTHOR]

The active injection system was designed to study the explosion flame propagation behavior of premixed CH 4 /H 2 /air mixtures in the closed tube with inert gas injection. The injection of inert gases (N 2 , CO 2 , and air) was controlled by the injection time, t inject , which is set from 0 ms to 210 ms. The effects of injection disturbance and inert gas dilution on flame morphology, flame tip dynamics, and overpressure build-up have been investigated. Results show that the injection of inert gas into premixed CH 4 /H 2 /air flame wrinkles the early laminar flame, changing the flame structure. The increase in t inject shortens the flame propagation time and increases the maximum explosion pressure, but the maximum value is attained at t inject = 120 ms. The linear relationship between maximum explosion pressure and maximum flame tip velocity is presented. The addition of inert gas dilutes the fuel-air mixture, but the inert gas shows some inhibition effect on the turbulent explosion flame propagation at t inject > 120 ms. The injection disturbance plays a dominant role in the flame propagation process compared to inert gas dilutions. Finally, the effect of Darrieus-Landau and Rayleigh-Taylor instabilities on explosion flame propagation behavior has been examined. The injection of inert gas into premixed CH 4 /H 2 /air flames creates local turbulence, enhances flame instabilities, and provides positive feedback on the flame's acceleration and oscillation. • Effect of inert gas injection on premixed CH 4 /H 2 /air explosions is investigated. • The injection disturbance plays a dominant role in explosion flame propagation behavior. • The injection of inert gas shortens flame propagation time and increases the explosion pressure. • Effect of inert gas type and injection time on explosion parameters are confirmed. • Injecting inert gas into the explosion flame changes the DL and RT instabilities. [ABSTRACT FROM AUTHOR]

The rapid development of hydrogen refueling station (HRS) has induced potentially serious risk exposure to public safety. Consequently, the safety issues associated with HRS have become a research hotspot. A comprehensive methodology for risk analysis of hydrogen facilities was proposed. A failure tree analysis (FTA) was used for hazard analysis while a bow-tie diagram and Bayesian network were applied to model the worst-case accident scenario and to analyse the risks of root event. In addition, the fuzzy set theory combined with FTA was employed to calculate the failure probability of the hydrogen facilities. The risk analysis of a HRS was implemented with the proposed method. The results showed that the vapour cloud explosion (VCE) of compressors in the gas HRS was the most risky scenario with the probability of 8.12E–04 before taking safety measures. The death, severely injured, and minor injured radius of the VCE from compressors was 35.5, 20.0, and 10.3 m, respectively. Results also revealed that after taking several safety barriers, the risk level converted from an intolerable risk level to a tolerable risk with control level. • A methodology for risk analysis of hydrogen facilities was proposed. • Bow-tie and Bayesian network were applied to model the hydrogen accident scenario. • Hydrogen leak from the dispenser was most likely to occur. • Risk of the HRS without safety barriers was unacceptable. [ABSTRACT FROM AUTHOR]

Large-scale coal mine gas explosion (CMGE) accidents have occurred occasionally and exerted a devastating effect on society. Therefore, it is essential to systematically identify the characteristics and association rules of causes of CMGE accidents through analysis on large-scale CMGE accident reports. In this study, 298 large-scale CMGE accidents in China from 2000 to 2021 were taken as the data sample, and mathematical statistical methods were adopted to analyze their general characteristics, coupling cross characteristics, and characteristics of gas accumulation and ignition sources. Moreover, the text mining technology and the Apriori algorithm were used for exploring the formation mechanism of CMGE accidents, during which 46 main causal factors were identified and 59 strong association rules were obtained. Furthermore, an accident causation network was constructed based on the co-occurrence matrix. The key causal items and sets of CMGE accidents were clarified through network centrality analysis. According to the research results, electrical equipment failure, cable short circuit, mine lamp misfire, hot-line work, and blasting spark are the key ignition sources of CMGE. Fan failure, airflow short circuit, and local ventilation fan damage are the main causes of gas accumulation. Besides, the confidence levels of two association rules of "static spark-fan failure" and "blasting spark-airflow short circuit" are higher than 70%, indicating that they are the two dominant risk-coupling paths of gas explosions. In addition, six causes appear frequently in the shortest risk paths of gas explosion and are closely related to other causes, i.e., fan failure, local ventilation fan damage, static sparks, electrical equipment failure, self-heating ignition, and friction impact sparks. This study provides a new perspective on identifying causes of accidents and their complex association mechanisms from accident report data for practical guidance in risk assessment and accident prevention. [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]

Gas explosion accidents can easily lead to large-scale casualties and economic losses, significantly impeding the urban development. The purpose of this study was to comprehensively review and investigate a significant gas fuel explosion accident in Yinchuan City, China, and to conduct an in-depth discussion on process traceability, failure risk, hazard prevention, and urban development related to the accident. The research found that the accidental failure of double-valve liquefied petroleum gas cylinders and human error were identified as the direct causes of gas leakage. The numerical results indicated that the progression of the accident disaster was chaotic and highly destructive. The maximum explosion overpressure of 92 kPa resulted in severe shock-wave damage to personnel, leading to the complete destruction and collapse of the 0.2 m thick solid brick wall and obstructing the stairway for escape. The rapid change in temperature and oxygen levels caused by the explosion led to the risk of burns and asphyxiation for personnel at the scene. By utilizing the system safety theory, a gas leakage accident control structure system was developed. This system comprised four key levels: the local government, gas management department, gas company, and individual user. The tragedy of 31 deaths was ultimately caused by a serious lack of safety constraints on the behavior of the lower level by the higher level. The research conclusions are of great significance for preventing clean fuel explosion accidents and ensuring sustainable urban development, especially in the face of the negative impact of accidents. [ABSTRACT FROM AUTHOR]

To comprehensively understand the explosion risk in underground energy transportation tunnels, this study employed computational fluid dynamics technology and finite element simulation to numerically analyze the potential impact of an accidental explosion for a specific oil and gas pipeline in China and the potential damage risk to nearby buildings. Furthermore, the study investigated the effects of tunnel inner diameter (d = 4.25 m, 6.5 m), tunnel length (L = 4 km, 8 km, 16 km), and soil depth (primarily Lsoil = 20 m, 30 m, 40 m) on explosion dynamics and on structural response characteristics. The findings indicated that as the tunnel length and inner diameter increased, the maximum explosion overpressure gradually rose and the peak arrival time was delayed, especially when d = 4.25 m; with the increase in L, the maximum explosion overpressure rapidly increased from 1.03 MPa to 2.12 MPa. However, when d = 6.5 m, the maximum explosion overpressure increased significantly by 72.8% from 1.25 MPa. Evidently, compared to the change in tunnel inner diameter, tunnel length has a more significant effect on the increase in explosion risk. According to the principle of maximum explosion risk, based on the peak explosion overpressure of 2.16 MPa under various conditions and the TNT equivalent calculation formula, the TNT explosion equivalent of a single section of the tunnel was determined to be 1.52 kg. This theoretical result is further supported by the AUTODYN 15.0 software simulation result of 2.39 MPa (error < 10%). As the soil depth increased, the distance between the building and the explosion source also increased. Consequently, the vibration peak acceleration and velocity gradually decreased, and the peak arrival time was delayed. In comparison to a soil depth of 10 m, the vibration acceleration at soil depths of 20 m and 30 m decreased by 81.3% and 91.7%, respectively. When the soil depth was 10 m, the building was at critical risk of vibration damage. [ABSTRACT FROM AUTHOR]

Hydrogen energy is favored as an ideal clean energy source, and doping hydrogen into natural gas pipelines is an effective way to realize large-scale delivery of hydrogen energy. Once pipelines leaking during transportation, the safe operation of pipelines will be seriously affected. At present, the leakage and diffusion law of hydrogen-doped natural gas buried pipelines in tunnels is not clear. A numerical model of leakage and diffusion for hydrogen-doped natural gas buried pipelines in tunnels was established to study the effects on hydrogen doping ratio (volume fraction), leakage aperture and incoming wind speed of leakage and diffusion characteristics of the gas mixture. The results show that hydrogen-doped natural gas accumulates at the top of tunnel after leaking, showing the phenomenon of high concentration in the center area and low concentration in the edge area. With the increase of hydrogen doping ratio, the lower explosion limit of the gas mixture decreases, and the leakage volume increases. Due to the confined space of tunnel, the gas mixture can not be fully diffused in a short period of time, so the larger the hydrogen doping ratio, the larger the explosion area, and the shorter the time to reach explosion limit. When hydrogen doping ratio increases from 5% to 20%, the explosion danger area increases by 3.18%, the gas to reach explosion limit time decreases by 3.7%. As the leakage aperture increases, the leakage amount of the mixed gas increases, the explosion danger area increases, and the time for the mixed gas to reach the explosion limit decreases. When leakage aperture increases from 20 mm to 100 mm, the distance from ground to the explosion danger area in the radial direction of tunnel decreases from 1.49 m to 0.30 m, the axial explosion danger area increases from 13.4 m to 91.9 m, and the time for gas to reach explosion limit decreases from 95.2 s to 11.3 s. The advection transport effect of incoming wind speed promotes the diffusion of mixed gas along axial direction of tunnel, reduces the high concentration area at the top of tunnel, and makes the explosion danger area significantly smaller. When incoming wind speed increases from 0.5 m/s to 2.0 m/s, the explosion danger area decreases by 81.7%. Therefore, tunnels should be ventilated in time when gas leakage occurs to avoid the occurrence of combustion and explosion. The results of this study can provide a theoretical basis for the safe operation of hydrogen-doped natural gas buried pipelines. [ABSTRACT FROM AUTHOR]

To investigate the changes in conditions within a blind roadway when multiple gas explosion sources are simultaneously detonated, the fluid dynamics software Fluent14.0 was used to conduct numerical simulation experiments with different numbers (2 and 3) and varying intervals (5 m, 10 m, and 15 m) of explosion sources. The results revealed that multiple explosion sources in gas explosions generate shock waves that propagate in opposite directions, creating pressure overlap zones within the roadway. The pressure waves and shock waves in these overlap zones continuously couple within the roadway. The number of overlap zones decreases incrementally with each encounter of opposing shock waves in the roadway. Unlike single explosion source models, the pressure at various positions within the roadway in multiple explosion source models oscillates due to the coupling of multiple shock waves, with significant peak pressures occurring at the closed end of the roadway and in the pressure overlap zones. Additionally, the propagation patterns of shock waves and flames within the roadway are not associated with the interval distance between explosion sources, whereas the encounter time, speed, and pressure of shock waves increase with the interval distance. [ABSTRACT FROM AUTHOR]

This study conducted various explosion experiments under different porous obstacle conditions of blockage ratio (BR) and void fraction (Φ f). The impact of porous obstacle on flame propagation velocity (v) and peak overpressure (P op) were analyzed. The results indicate that an increase in the BR enhances explosion pressure near the blockage area for both porous and non-porous obstacles. However, it also increases the downstream pressure decline gradient. An increase in the Φ f weakens the hindrance of porous obstacle on the flame propagation, allowing more flame to pass through the internal void channels of obstacles, thus delaying the downstream pressure decay. Compared to non-porous obstacles, gas explosions disturbed by porous obstacles with both high BR (BR＞75%) and high Φ f (Φ f ＞0.55) exhibit a lower downstream pressure decline gradient and a longer positive pressure duration. As a result, the explosion can produce a broader range of destruction. • The impact of porous and non-porous obstacles on flames was compared. • The propagation stability of flame gradually reduces with an increasing BR. • Increasing BR results in the forward shift of the maximum P op point. • Increasing V f tends to delay downstream explosion pressure decline. • Porous obstacles can amplify the destructive range of explosion. [ABSTRACT FROM AUTHOR]

The reasons for the mistakes underlying the neglect and denial of the reaction chains discovered by N.N. Semenov and S. Hinshelwood in the combustion of gases at pressures close to atmospheric are analyzed. A method for unequivocal experimental proof of the chain nature of gas combustion is described. Examples are given proving the chain nature of combustion and explosion in a wide range of pressures and temperatures. [ABSTRACT FROM AUTHOR]

To address the problem of large tractive resistance in traditional subsoiling methods, this paper designed a pulse-type gas explosion subsoiler, as well as an air-blown double-ended chisel type subsoiling shovel and a conduit. The mathematical equation of the influence of the structural parameters of the subsoiler on the groove profile is established. The EDEM 2022 software was used to simulate the subsoiling operation process. The soil disturbance law of the chisel subsoiler was analyzed by the change of soil particle velocity. The optimum value interval of quadratic regression orthogonal rotation combination test factors was determined by using the steepest climb test, with specific tillage resistance and filling power as evaluation indicators. Based on the Box–Behnken design test, a second-order regression model of response value and significance parameter was obtained, and an optimal combination was found by optimizing the significance parameter. The effects of subsoiling air pressure, pulse width and pulse interval on evaluation indicators were analyzed by the response surface method; the test results show that when the air pressure was 0.8 MPa, the pulse width was 0.17 s and the pulse interval was 0.12 s, and the specific tillage resistance was 0.4421 N/mm2 and the filling power was 18.5%; a comparative test between the pulse-type gas explosion subsoiler and a continuous gas explosion subsoiler was carried out, and the specific tillage resistance was reduced by 12.2% and the filling power was reduced by 10.5%; the comparative test shows that the pulse-type gas explosion subsoiler has smaller tractive resistance per unit area and smaller disturbance to soil. The research results provide a theoretical basis and reference for the optimization and improvement of gas explosion subsoilers. [ABSTRACT FROM AUTHOR]

Copyright of China Mining Magazine is the property of China Mining Magazine Co., Ltd. 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 suppression effect of inert powder on gas-induced suspension coal dust explosions was investigated using a semi-closed pipeline experimental platform. The shock wave overpressure propagation characteristics of gas explosions with different concentrations of mixed dust (calcium carbonate and coal dust) were measured and analyzed. The suppression mechanism of inert powder on the explosion process was also discussed. The results indicate that when the coal dust concentration is 200 g/m³, the peak overpressure of the explosion decreases gradually with increasing inert powder concentration, and the peak overpressure ratio in the pipeline shows a decreasing-increasing trend. The acceleration of the explosion pressure reduces with increasing mixed dust concentration, and when high concentration of mixed dust is involved in the explosion, the acceleration of the explosion pressure is lower than that when only coal dust is involved. The inhibitory effect of calcium carbonate on dust explosion increased linearly with its concentration when the ratio of inert dust to coal dust was 1:2. Inert powder mainly suppresses the explosive power by physical heat absorption and reducing heat exchange efficiency. The experimental results established the theoretical basis for inert dust suppressing coal dust participation in explosions, and have reference significance for formulating mine explosion suppression measures. [ABSTRACT FROM AUTHOR]

In order to elucidate the overpressure and fire hazard effects of gas explosion in a congested room, the effects of gas concentration and room layout on a gas explosion in a kitchen were studied by CFD. The results showed that the flow field parameters in a kitchen exhibited an initial increase followed by a decrease as the gas concentration increased. The maximum gas flow rate recorded within the chamber was 390 m/s, while the corresponding maximum flame propagation rate and peak pressure reached 289.86 m/s and 30.95 kPa, respectively. The difference in the flow field induced by the concentration was further enhanced by the presence of congested materials. Additionally, the room layout influenced the gas congestion's blowout effect due to variations in turbulence intensity and flammable gas volume caused by significant changes in the congestion within the room. Specifically, when the gas concentration was 10%, the order of indoor gas flow rate and flame combustion rate were II > U > L > I, while the turbulent kinetic energy and explosive overpressure followed the order I > II > L > U. The results are of great significance for the disaster assessment and accident prevention of natural gas explosion in civil kitchens. [ABSTRACT FROM AUTHOR]

Background: An intravesical gas explosion is a rare complication of transurethral resection of the prostate (TURP). It was first reported in English literature in 1926, and up to 2022 were only forty-one cases. Injury from an intravesical gas explosion, in the most severe cases appearing as extraperitoneal or intraperitoneal bladder rupture needed emergent repair surgery. Case presentation: We present a case of a 75-year-old man who suffered an intravesical gas explosion during TURP. The patient underwent an emergent exploratory laparotomy for bladder repair and was transferred to the intensive care unit for further observation and treatment. Under the medical team's care for up to sixty days, the patient recovered smoothly without clinical sequelae. Conclusions: This case report presents an example of a rare complication of intravesical gas explosion during TURP, utilizing root cause analysis (RCA) to comprehend causal relationships and team strategies and tools to improve performance and patient safety (TeamSTEPPS) method delivers four teamwork skills that can be utilized during surgery and five recommendations to avoid gas explosions during TURP to prevent the recurrence of medical errors. In modern healthcare systems, promoting patient safety is crucial. Once complications appear, RCA and TeamSTEPPS are helpful means to support the healthcare team reflect and improve as a team. [ABSTRACT FROM AUTHOR]

Copyright of Modares Mechanical Engineering is the property of Tarbiat Modares University Press 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.)