Explosion Area Research Articles

Chemiresistive triethylamine detection based on the novel Ti3C2Tx/Co-BDC gas sensor

Triethylamine (TEA), a representative volatile organic environmental pollutant, poses significant environmental pollution risks and can adversely affect the liver and nervous system, potentially leading to fatal outcomes. However, existing gas sensors for TEA detection have pressing drawbacks, such as safety hazards associated with high-temperature operation and poor timeliness due to time-consuming testing. Herein, the Ti3C2Tx/Co-BDC sensor demonstrates ultra-sensitive detection of TEA at a low temperature of 100 °C. This temperature is below the threshold for explosion-proof operation, ensuring safe application in flammable and explosive environments. Meanwhile, the introduction of the metal-like MXene with ultra-high conductivity accelerates the response and recovery process (11 s/20 s), facilitating highly efficient TEA detection within a sub-minute timeframe. The Ti-O-Co interfacial bonds between Ti3C2Tx and Co-BDC, confirmed by both XPS analysis and theoretical calculations, enhance carrier mobility across the two materials, significantly boosting gas-sensing performance. The rapid detection of TEA at low temperatures makes the Ti3C2Tx/Co-BDC sensor more suitable for practical environmental monitoring in flammable and explosive areas, further contributing to human health and production safety.

Quantitative risk assessment of coal mine gas explosion based on a Bayesian network and computational fluid dynamics

A gas explosion is one of the most serious coal mine accidents. The complexity and dynamics of gas explosion accidents, resulting from both multiple risk factors and time-dependent physical parameters, necessitates the use of risk assessment techniques to analyze the accident. A quantitative risk assessment method is proposed for coal mine gas explosions based on a Bayesian Network (BN) and Computational Fluid Dynamics (CFD). The results show that, in addition to the problems of “low vigilance” and “substandard safety education”, the “irrational design of mine gas extraction” has become another major risk factor at the new stage of development of mine excavation technology. Three typical gas explosion areas are selected to analyze the possible consequences of an accident. Based on the probabilistic risk assessment model, time-dependent physical parameters such as accident conditions, location and time are analyzed. The probability of occurrence of time-dependent risk factors is quantified to calculate the risk values of the consequences of explosion accidents corresponding to different times. The proposed method helps to improve the calculation accuracy of updating the risk probability value over time and provides theoretical support for the risk analysis of coal mine gas explosion accidents.

Palestine in a Vicious Circle of Violence, Wars and Terror (1948–2023)

This article deals with one of the most explosive areas of the world today, which is the Near and Middle East (NMEA) and especially the territory of historical Palestine, where the Israeli-Palestinian conflict (IPC) has been going on for a long time. The text deals primarily with historical and military factors and is written as a historical explanatory analysis. It focuses on the most significant historical events and explains the ways of functioning and the consequences of the processes that have been taking place there for a long time.

Simulation on the Dispersion of Natural Gas and its Volume Cloud Distribution on an Offshore Fixed Platform

The formation, migration and volume distribution of gas clouds, which are dominated by natural gas after oil and gas leakage, are the material basis of fire and explosion accidents on offshore platforms. Based on an offshore platform as the background, this paper conducts research on the gas cloud using numerical simulation method, the selection of different wind speeds, leak leakage rate of quality, wind direction and the direction angle, the leakage of gas diffusion behaviour simulation studies and its size distribution. There is a “coupling” effect on the volume value of 5% CH4 cloud between different wind speeds, leakage mass rates, and wind direction and leakage direction. When the wind speed is 13 m/s, the leakage mass velocity is 8 kg/s, and the included angle between wind direction and leakage direction is 180°, the “coupling” effect on the volume value of 5% CH4 cloud increases significantly. The above research results can provide a reference for the reasonable division of process risk area, firewall design and quantitative risk assessment of fire and explosion of an offshore platform.

Data Secure De-Duplication in Cloud Environment

In the current area of information explosion, users’ demand for data storage is increasing, and data on the cloud has become the first choice of users and enterprises. Cloud storage facilitates users to backup and share data, effectively reducing users’ storage expenses. As the duplicate data of different users are stored multiple times, leading to a sudden decrease in storage utilization of cloud servers. Data stored in plaintext form can directly remove duplicate data, while cloud servers are semi-trusted and usually need to store data after encryption to protect user privacy. In this paper, we focus on how to achieve secure re-duplication and recover data in ciphertext for different users, and determine whether the indexes of public key searchable encryption and the matching relationship of trapdoor are equal in cipher text to achieve secure de-duplication. For the duplicate file, the data user’s re-encryption key about the file is appended to the ciphertext chain table of the stored copy. The cloud server uses the re-encryption key to generate the specified transformed ciphertext, and the data user decrypts the transformed ciphertext by its private key to recover the file. The proposed scheme is secure and efficient through security analysis and experimental simulation analysis.

Simulation and Experimental Verification of Dispersion and Explosion of Hydrogen–Methane Mixture in a Domestic Kitchen

Hydrogen is a carbon-free energy source that can be obtained from various sources. The blending of hydrogen represents a transitional phase in the shift from natural gas systems to hydrogen-based systems. However, concerns about the safety implications of introducing hydrogen have led to extensive discussions. This paper utilizes Fluent 17.0 numerical simulation software to simulate the leakage of hydrogen-blended natural gas in a closed domestic kitchen and analyze the concentration distribution and its variation pattern after a leakage. An experimental platform is set up, and a mixture of nitrogen and helium gas is used as a substitute for hydrogen-blended natural gas for the simulations and experiments. The simulation results demonstrate that the leaked gas spreads and accumulates towards the top of the space, gradually filling the entire area as the leak persists. As the hydrogen content in the leaked gas increases, the dispersion capacity of the gas in the confined space also increases. Furthermore, as the flow rate of the leaked gas increases, the average concentration of the leaked gas rises, and the gas stratification in the confined kitchen diminishes. The concentration distribution observed in the experiments aligns with the simulation results. After establishing the feasibility conditions of the model, the dispersion of the hydrogen-blended natural gas in the kitchen is further simulated. The results suggest that blending hydrogen into the gas enhances the dispersion of the gas after a leak, leading to a wider distribution within the kitchen and an increased risk in the event of a leak. Additionally, this paper employs the CASD module of FLACS 11.0 software to construct a three-dimensional geometric model of the domestic kitchen for simulation studies on the explosion of hydrogen-blended natural gas in a confined space. By adjusting the hydrogen ratio in the combustible gases present in the space and examining the variations in hydrogen concentration and external conditions, such as opening or closing the door, the influence on parameters including the peak explosion pressure, explosion overpressure, explosion flame temperature, and explosion response time are examined. Furthermore, the extent of the explosion area is determined, and the effect of hydrogen on the blast is clarified.

Experimental simulation study on gas flow field in combined goaf during the transition period of coal pillar-free working face relocation

Regarding the gas disaster caused by the complex ventilation system and the changeable flow field in the combined goaf during the transition period of the coal pillar-free working face, the self-designed physical simulation test bench for the combined goaf of coal pillar-free mining was used to compare and analyze the distribution law of wind pressure, gas, and oxygen concentration field in the combined goaf during the moving period of the working face and the normal mining period. The results show that during the relocation period, the gas concentration in the stope will always be slightly higher than that in the normal mining period, and the existing air leakage channel will lead to complex air flow in the combined goaf, which is easy to cause gas explosion accidents. The formation conditions, judgment principles, and judgment methods of the dangerous area of gas explosion coupling disaster in goaf are analyzed. By changing the air distribution ratio of the main and auxiliary air intake roadways, it is concluded that the explosion area will form an “L”-shaped explosion zone in the goaf, and the area of gas explosion disaster area during the relocation period will be larger than that the normal mining period. According to the size of the gas explosion area, the optimal air distribution ratio of the main and auxiliary air intake roadway during the transition period of the working face relocation and the normal mining period is 2:1. Under this air distribution ratio, the gas explosion area is the smallest, which is 132 284 and 113 534 mm2, respectively. The research results are of great significance to reveal the mechanism of gas disaster induced by goaf during the transition period of coal pillar-free relocation.

Comparative analysis of permeability model construction and risk fields evaluation by roof cutting along the gob in a coal mine.

The productivity of coal mines is seriously threatened by the combined disasters of gas and coal spontaneous combustion, which have become a common disaster mode. It is unclear how the gas and coal spontaneously combusted in the roof cutting along gob working face. The goal of this study is to identify the distinctive features of combined disasters in gob from two different types of roof cutting along working faces. In these two different types of roof cutting along gob working faces, the paper constructs the permeability model of the gob. The findings demonstrate that the data from the field experiment and the simulation results agree, which validates the simulation's reliability. In contrast to single sided roof cutting along gob working faces, double sided roof cutting along gob working faces clearly has a thinner oxidation zone. Moreover, the oxidation zone of the double side roof cutting along gob working faces is closer to the working face, which is located in the shallow area of the gob 50m behind the working face. The gas explosion area and the coal spontaneous combustion area are divided by the double side roof cutting along gob working face, which reduces the risk of compound disasters. Important theoretical direction for the prevention and control of gob disasters in the roof cutting along gob working face is provided by the simulation results.

Study on the effect of venting conditions on methane-air explosion characteristics in full-scale mine tunnel

The overpressure and heat products generated by methane explosions seriously threaten human life. Therefore, studying the influence mechanism of venting conditions on methane explosion characteristics in full-scale tunnels is of great significance for preventing and controlling methane explosions in mines. This study takes the Lynn Lake experimental mine (LLEM#501) as a background case, and studies the changes in methane explosion characteristics under different sealing ratios in full-scale tunnel using the GASFLOW-MPI code. The study shows that the greater the sealing ratio, the larger the maximum overpressure, maximum fluid velocity, and reflection wave overpressure in the methane explosion area. As the sealing ratio increases, the coupling effect of gas expansion and reflected shock wave overpressure causes a decrease in both the negative pressure value and the negative pressure area in the explosion zone. When the area is completely sealed, there is no formation of negative pressure. High-temperature heat products and flame backflow by cavity structures is the main factor that causes local temperature anomalies to increase and oscillations. Heat loss is a crucial factor influencing methane explosions, with approximately 22.75 % to 25.77 % of the explosion energy being dissipated in the form of heat during the explosion process. As the sealing ratio increases, the heat loss during the explosion process shows an exponential decrease trend. By analyzing the methane explosion energy equation, it has been determined that the decrease in heat loss during the methane explosion process is the primary cause for the increase in methane explosion overpressure and velocity.

CFD modeling of subsonic and sonic methane gas release and dispersion

AbstractIn the event of a flammable liquid, gas, or vapor release the first step is to identify the type of outflow, which can fall into two categories sonic or subsonic. The two types of outflows carry different flow characteristics, which effect on the extent of the potentially explosive areas. In case of subsonic outflow, a short jet is formed without turbulent flow conditions at low velocity, which appears more concentrated around the source of release. With sonic outflow, a high velocity jet is formed with turbulent flow properties, which can extend further away from the source of release. The simulations examine the lower explosion limit of the flammable medium around the vessel where LEL20% or LEL40%. In addition, high temperature methane gas release was also presented.

Study on the evolution characteristics of coal spontaneous combustion and gas coupling disaster region in goaf

In order to study the evolution of multiple fields and the risk degree of combined disasters in the process of coal spontaneous combustion under the gas-containing environment in the goaf, a simulation platform for the thermal test of the thermal dynamic disaster in the goaf was built, and the gas–solid coupling heat transfer of multi-component gas model for coal spontaneous combustion was constructed. Through similar simulation experiments and numerical simulation, it is clear that the gas accumulation law during the coal spontaneous combustion process in the goaf. The ventilation process causes the gas to be driven along the air leakage channel to the deep part of the air-return side of the goaf, and finally a high gas concentration area is formed. Meanwhile, the change of gas density inside and outside the high-temperature area causes a small area of gas accumulation that migrates with the coal spontaneous combustion. According to the results of experiments and simulations, a risk assessment model of coal spontaneous combustion and gas combined disaster based on the dimensionless dynamic explosion limit of multi-gas was constructed. It is found that due to the massive consumption of oxygen by coal spontaneous combustion, the hazardous area of gas explosion has been continuously reduced, but the risk has been continuously increased. The risk of combined disasters is close to 1 in the corners of the working face and the back of the working face.

Effects of Water Mist Concentration and Droplet Size on Gas-Liquid Two-Phase Detonation

ABSTRACT The effects of water mist concentration and droplet size on the inhibition of gas-liquid two-phase detonation are studied. The characteristics of the structure of the detonation wave, the interaction between the detonation wave and water mist, and the mechanism of water mist inhibition are analyzed. The interaction between iso-octane gas-liquid detonation wave and water mist results in the inhibition of the chemical reaction, and the decrease of combustion rate is the basic reason for the inhibition of water mist. Under the action of detonation waves, water mist flows and evaporates at high velocity, and the heat absorbed by evaporation reduces the chemical reaction rate of fuel to achieve effective inhibition of the detonation. The flame front and pressure wave front of the detonation wave are basically synchronous; after the detonation wave is effectively inhibited by water mist, the length between the pressure wave front and flame front increases gradually. The detonation inhibition effect improves with increasing water mist concentration in the range of 120–350 g/m3 in the model. The inhibition of detonation increases slightly as the size of water mist decreases in the range of 50 μm-200 μm. The optimal concentration range and droplet size range of water mist to inhibit explosion are obtained. The achievements provide an important reference for the design of explosion inhibition by water mist in hazardous explosion areas and have potential applications.

Investigating the Challenges of Ammonia Emission in Firuzabad Sodium Carbonate Factory Incident: A Case Study

Background: An ammonia gas explosion poses immediate health hazards such as respiratory tract burns, skin and eye irritation, and potential death within seconds. It also causes long-term negative impacts on biodiversity, affecting aquatic life and vegetation. An explosion in the Firuzabad sodium carbonate factory in Iran led to massive ammonia gas leakage and the poisoning of several employees. This study evaluates the risks of ammonia gas release caused by the explosion and the rescue team’s response in the same factory. Materials and Methods: This study was conducted in 2020 in Firuzabad City, Iran. The investigation was based on case reports and data analysis obtained via field observations, document reviews, interviews, and experiments. Technical and specialized information on explosion were analyzed by ALOHA software. Results: Based on data analysis, red, orange, and yellow zones around the explosion area were identified. The red zone had an ammonia emission range of 1.2 km with an explosive power of 10 kW, causing potential death in 60 seconds. Orange zone had a range of about 1.7 km, an explosive power of 5 kW, and the potential for second-degree burns and respiratory damage within 60 seconds of release. The yellow zone covered an area of about 3.3 km. Interviews and field observations provided information on the risk-based response process, response equipment, medical treatment, hazardous materials, handling and response equipment, personal protective equipment, mutual aid, and resource typing. Conclusion: The results of this study show that the immediate evacuation of the area, employment of the rapid warning system, the triage of the injured, the presence of an emergency operation plan to control hazardous and toxic materials disasters, the performance of the rapid response team and multi-specialty teams were among the existing challenges of the operation team. Background of this study confirms the potential hazards associated with ammonia gas emissions from explosions in sodium carbonate plants.

STUDY OF THE STRUCTURE AND PROPERTIES OF THE SURFACE OF HARD ALLOY VK10KS AFTER TWO-COMPONENT ELECTRICAL EXPLOSION TREATMENT WITH SYNTHETIC DIAMONDS

The article presents the results of studies of the VK10KS hard alloy after two-component electroexplosive treatment (EVL) with synthetic diamonds. Aluminum was used as the exploding conductor. The choice of aluminum is based on the experimental data of a number of researchers who note that in order to increase the strength properties of hard alloys at elevated temperatures, it is necessary that particles with a size of hundredths of a micron of ultrafine α-Al2O3 be present in the cobalt binder. Thus, the addition of aluminum to the bond significantly increases the hardness, wear resistance and bending strength. The essence of the EVL is the accumulation of energy by a battery of impulse capacitors up to 10 kJ and its subsequent discharge for 100 μs through a conductor that experiences explosive destruction. In this case, the treated surface is heated and saturated with explosion products, followed by self- hardening due to heat removal to the environment and deep into the material. To increase the hardening effect, a powder sample of synthetic diamond powder AC2 weighing 60 mg was additionally added to the explosion area. It was experimentally revealed that alloying the surface of the VK10KS hard alloy with the products of aluminum electric explosion with a sample of diamond powder did not lead to the formation of a hardened diamond-type layer. During processing, the diamond powder trans-formed into graphite. Despite the fact that the diamond layer was not formed, surface hardening of the VK10KS hard alloy occurred after the electric explosion of diamond powder with aluminum as a conductor. The thickness of the hardened surface layer is about 15 µm with a nanohardness of 24000 MPa, which is 2 times higher compared to the initial state. The increase in hardness is associated with the refinement of phases in the surface layer and the formation of W2C and α-Al2O3 type carbides. The surface roughness of machined carbide inserts does not exceed the values corresponding to the technical requirements.The study of the cobalt binder in the heat-affected zone after two-component EVL found that the cobalt binder is additionally alloyed with tungsten, carbon, aluminum, which are part of the explosive materials and the base. Additional alloying of the cobalt binder will lead to its hardening, which will positively affect the service life of tungsten carbide hard alloys in general.

The Mechanism of Plugging Open-Pit Mine Cannon Holes and the Modification of Plugging Materials

Step blasting is an important part of open-pit mining, which is accompanied by hazards such as large blasting blocks, flying stone splashing, blasting noises, and blasting dust during the blasting process. In order to reduce the harm caused by blasting, this paper uses impact dynamics and rock dynamics to explain the deformation damage and motion law caused by detonation of the material blocked by the gun hole. By simulating the motion of the blocked material in the gun hole, the motion and failure characteristics of the blocked material in the gun hole are revealed. In this paper, geological polymer is introduced into the field of open-pit mine blasting, and 700 g rock powder, 200 g slag, 40 g NaOH solution (30%), and 140 g water glass with a modulus of 3.2 and 80 g of water are selected to prepare geological polymer-modified plugging materials to change rock powder blockage from bulk to solid, and improve the plugging performance. Finally, a field test was carried out in the open-pit mine explosion area, and a comparative test was carried out through the high-speed photography system; it is demonstrated that the modified blocking material could improve the blockage ability of the gun hole, reduce the large block rate of the upper part of the step, reduce the amount of dust, reduce the amount of flying stone, and improve the production efficiency and safety.

Influence of military actions on the process of the formation of precipitation

This work concerns the study of the influence of military actions on the development of global ecological processes, in particular, the fall of acid rain from individual single explosions. A mathematical model is proposed, which takes into account the emission of pollutants into the subcloud washout zone and the kinetics of the condensation process. The concentration of combustion products in the atmosphere at the level of three to five diameters of the explosion area (the area of the formed explosion funnel) is found using the theory of a convective jet from a warm source to the environment. At the same time, we determined the speed of warm air that rises above the area of the explosion, the average temperature in the transition section of the convective jet, and the flow rate of polluted air in the upper part of the jet. The paper presents a system of dimensionless non-stationary differential equations for a high unshaded source, which can be used to determine the dispersion of the main acid-forming substances in the Boussinesq approximation with the variables "eddy velocity – current function – temperature – concentration" with appropriate initial and boundary conditions. Sulfuric anhydride was considered as an example of the main acid-forming substances and the most dangerous and toxic compounds of explosion products. The proposed mathematical model can be used to forecast the possible fall of acid rain on the territories adjacent to single explosions, thereby making a forecast of changes in environmental risk as a result of military operations for the environment and the population. and will make it possible to determine the zones of influence and dispersion from the place of the explosion.

Formation of Vortex Structures in an Area of Strong Explosion in a Nonuniform Atmosphere at Its Early Stage

Formation of Vortex Structures in an Area of Strong Explosion in a Nonuniform Atmosphere at Its Early Stage

Estimation of Blast-resistant Buildings Using Weight Product Method

This research is architectural space in blast-resistant buildings Aims to determine status and its effective indicators. Explosion-proof structures are necessary to protect personnel from construction hazards created when personnel work in potentially explosive areas. Blast-proof buildings usually precast cast-in-place concrete or Constructed of steel frosted steel frames are permanent structures. Suitable types of window glass and provides specific recommendations on contraindications. Incorporating blast-resistant glazing into its framing and It mentions the considerations involved in linking. Most notably, laminated glass and made of laminated glass Based on traditional window glass design methods for insulating glass Authors relatively to simplify the design of explosion-resistant glazing them offer a simple approach. Weighted Production Method (WPM) is less important than TOPSIS method and a more stringent method for penalizing computationally cheaper alternatives. It is dimensionless and the rank abnormality problem is not applicable to WPM. Option code of each alternative independent of other alternatives, More acceptable One can set the limit for the option code. Hence, for dynamic decision-making situations we recommend WPM as a better alternative than TOPSIS. Blast resistant building is alternatives are reconstruction capability (C1), implementation costs (C2), access to material supply (C3), maintenance costs (C4), environmental footprint (C5) and reduction of energy loss (C6). Evaluation Parameter is Brick Façade (A1), Stone Façade (A2), Coatings Cement Façade (A3) and Composite Façade (A4). In this type of analysis, WPM methods determine for the best solution to settlement, As a result, access to material supply (C3) is got the first rank whereas is reconstruction capability (C1) is having the lowest rank.

Numerical study of gas leakage from a pipeline and its concentration evaluation based on modern and practical leak detection methods

Gas leaks from pipelines may cause human casualties and economic losses. Consequently, detecting gas diffusion in the environment and determining its concentration around pipelines can be essential. In the present research, leakage of natural gas due to the failure of pipelines is studied in both air and porous environments using three-dimensional simulations. Besides, the effective factors in increasing the concentration of exhaust gas in each of these environments have been investigated. Moreover, the effect of these factors on the explosion area is examined. To ensure the accuracy of the numerical method, with the aid of Isfahan Gas Company in Iran, a real leakage sample was tested, and a comparison of the experimental result with the numerical solution was carried out. Factors such as pipeline pressure, rupture diameter, wind velocity, and soil porosity are influential factors in the studied problem. The results of this simulation show that by increasing the pipeline pressure (413.68, 1723.68, 7239.4 Kpa) and increasing the diameter of the leak rupture (20, 50, 100 mm), an increase in the height of the explosion area will be induced. Further, the effect of wind velocity on the gas jet concentration has been examined. It was revealed that increasing the wind velocity reduces the height of the explosion area. Finally, by performing the simulation in a porous medium, it was concluded that increasing the soil porosity (0.1, 0.4, 0.7, 1) extends the explosion area.

Impact of Political Violence on People in Istanbul: The Role of Resilience in Posttraumatic Stress and Psychological Health

ABSTRACT The study investigated the effects of political violence on people exposed to terrorist attacks in Istanbul between 2015 and 2016, and the role of resilience in both psychological stress and posttraumatic stress. The data was collected from 172 people using the Resilience Scale for Adults (RSA), General Health Questionnaire-12 (GHQ-12), and Traumatic Stress Symptoms Checklist (TSSC). Only 25.9% of the participants who were directly exposed to terrorist attacks and 13.8%who were exposed indirectly, had probable posttraumatic stress disorder (PTSD). The frequency of probable PTSD was higher in participants who were present at the explosion area during the attack, provided either physical or emotional aid to a terror survivor, and who escaped from the attacks by chance. “Perception of future” and “perception of self” had a negative correlation with both TSSC PTSD scores and psychological stress scores. “Perception of future,” “family coherence,” “perception of self,” and “social resources” were negatively correlated with TSSC PTSD scores. In addition, “perception of future” and “perception of self” were negatively correlated with psychological stress scores. The psychological impact of ongoing exposure to violence is destructive; in a context of persistent violence, intervention strategies focused on resilience are essential for patient care.