Search Results (2,012)

Coal gasification slag (CGS) is rich in Si-Al-Ca components and thus has potential for ceramic utilization, but associated heavy metals may pose environmental risks. In this study, CGS from Yili (Xinjiang, China) was used as the major raw material (80 wt%), with clay and waste glass as additives, to prepare ceramsite by firing green pellets (8–12 mm) at 1000–1200 °C. The phase evolution, microstructure, and heavy-metal migration were characterized, and the leaching safety was evaluated. Increasing temperature leads to progressive quartz consumption, enrichment of feldspar-type crystalline phases, and liquid-phase sintering, which together enhance densification. The apparent density and single-particle compressive strength exhibit an “increase-then-decrease” trend with temperature and reach maxima at 1150 °C, where the compressive strength is 15.38 MPa. Heavy-metal behavior is element-specific: As and Zn show stronger volatilization, whereas Mn, Ba, Ni, and Cu are largely retained in the solid phase; Cr shows intermediate, temperature-dependent volatilization. After firing at ≥1150 °C, the leached concentrations of Cr, Mn, Ni, Cu, Zn, As, and Ba under the sulfuric acid–nitric acid test (HJ/T 299-2007) are below the Class III limits of the Chinese Groundwater Quality Standard (GB/T 14848-2017). Considering phase/structure evolution, mechanical performance, and short-term heavy-metal leaching, 1150 °C is identified as the preferred firing temperature in this work. Full article

Existing BIM (Building Information Modeling) validation mechanisms, namely geometric clash detection and attribute completeness checking of individual objects (MVD, IDS), do not cover a significant category of informational incompleteness: situations in which the properties of interdependent entities become fully defined only as a result of their mutual presence in the model. This article introduces the new concept of ontosaturation as a new mechanism of formal ontology that formalizes this phenomenon. Ontosaturation describes the relationship between existentially independent entities whose certain properties remain undetermined (unsaturated) in isolation and acquire values only after the attributes of related objects are taken into account. The article proposes a formal definition of ontosaturation and the supporting concepts needed to apply it in practice. These include the saturant (an entity that completes the properties of another), the saturation cluster (a group of mutually saturating entities), and the saturation index, a metric enabling a quantitative assessment of the relational completeness of a BIM model at the level of a single entity (s(e)) and the entire model (S(M)). The concept of a saturation profile was also introduced, complementary to the Level of Information Need (LOIN) in accordance with the ISO 19650 series of standards, defining minimum saturation thresholds for successive phases of the project lifecycle. The mechanism was demonstrated using the example of an installation penetration through a fire separation wall, modeled in Autodesk Revit 2025, showing that collision detection and attribute validation fail to detect four unsaturated properties critical to fire safety and structural integrity, which ontosaturation identifies. The proposed approach constitutes a third layer of BIM model validation, alongside the geometric and attribute layers, addressing the relational completeness of information between interdependent objects. Full article

While polyurethane acoustic foam is widely used in entertainment settings for sound absorption, it poses a considerable fire risk when exposed to sparks from pyrotechnic devices. Even though fountain-type pyrotechnic devices are often perceived as producing “cold sparks”, the ignition potential of a single incandescent particle remains insufficiently quantified. This study experimentally investigates the ignition capacity of a fountain-type pyrotechnic article on pyramidal polyurethane acoustic foam under controlled conditions. Three dedicated experimental configurations were developed: (i) ignition probability tests at various distances, (ii) scaled configuration tests reproducing realistic installation geometry, and (iii) high-speed visualization of single incandescent particle interaction with the foam surface. For the first two configurations, ignition probabilities of 20% and 22.2% were obtained. High-speed recordings showed two distinct interaction mechanisms: particle fragmentation and ricochet, which did not result in ignition; partial penetration with localized melting, volatile release, and gas-phase ignition when residual thermal energy (about 0.5–1 J) was retained. The results demonstrate that even isolated single incandescent particles generated under realistic conditions can initiate the combustion of polyurethane acoustic foam. These findings challenge the “cold spark” safety perception and provide quantitative evidence that particle–induced ignition represents a significant fire hazard in enclosed environments where combustible acoustic materials and pyrotechnic effects coexist. The findings in this paper have direct implications for safety regulations in entertainment venues. Full article

A ternary gel composed of polyvinyl alcohol (PVA), polyethyleneimine (PEI), and polyaluminum chloride (PAC) was prepared to address the limited controllability of gelation and the insufficient high-temperature resistance to re-ignition observed in existing mine fire prevention and extinguishing gels. Based on an orthogonal experimental design, the optimal formulation was identified as 14% PVA, 7% PEI, and 5.5% PAC (by mass), achieving a gelation time of 8.2 min. Microscopic characterization revealed that the gel forms a dense, interconnected three-dimensional network structure capable of effectively encapsulating the coal particles. Fourier transform infrared spectroscopy (FTIR) analysis showed that gel treatment resulted in a 29.8% reduction in the peak area of free hydroxyl groups. Thermogravimetric–differential scanning calorimetry (TG-DSC) analysis indicated that the gel increased the ignition temperature by 33.27 °C and shifted the maximum exothermic peak temperature by 13.28 °C. Fire suppression experiments demonstrate that the gel could continuously lower the temperature of high-temperature coal without re-ignition, demonstrating significantly superior performance compared to traditional sodium silicate gel. This gel achieves highly efficient fire prevention and suppression through the cooperative effects of water retention, oxygen barriers, and chemical passivation, providing a new material for the prevention and control of spontaneous coal combustion in deep mines. Full article

This study examines how different dimensions of leisure literacy relate to work–leisure boundary management and work performance in digitally connected workplaces, addressing the problem that leisure may function as either a restorative resource or a source of boundary conflict. Drawing on boundary theory, the study adopts an exploratory case-based survey design using data from 75 employees in a Taiwanese fire safety enterprise, combining self-reports, supervisor evaluations, and organizational records, with findings analyzed through correlation, subgroup comparison, and regression-based analyses. The results indicate differentiated pathways: positive leisure attitude is associated with work–leisure balance and higher self-rated performance, whereas excessive leisure involvement is associated with increased boundary conflict. These performance-related patterns were more consistently observed for self-rated than for supervisor-rated performance, so performance implications should be interpreted with appropriate caution. Leisure knowledge shows a regulatory role primarily in reducing conflict rather than directly enhancing balance. The results further suggest that comparative leisure/work importance conditions these relationships: when work and leisure are valued more equally, leisure literacy relates more directly to performance, whereas under value imbalance, boundary management becomes more salient, linking leisure literacy to work outcomes. Family life-cycle differences were also observed, although these are treated as contextual. Overall, the study suggests that leisure literacy may support sustainable work performance by shaping whether leisure functions more as a resource or as a source of friction. By extending boundary theory to the work–leisure interface, the study highlights boundary regulation as a relevant issue for sustainable human resource management in digitally connected environments, particularly under conditions of blurred work–leisure boundaries. Full article

DC fault arcs comprise one of the most serious safety hazards in photovoltaic systems, and their danger far exceeds that of AC arcs. DC arcs lack a natural zero-crossing point, and their burning time can last from several seconds to several minutes, which is sufficient to ignite cable lines and surrounding combustibles, causing fires. To explore the characteristics and mechanism of the ignition of external combustibles by DC fault arcs, this paper, based on the theory of magnetohydrodynamics (MHD), constructed a three-dimensional numerical simulation model of a DC fault arc considering the coupling of electromagnetic, thermal, and flow fields. A DC fault arc experimental platform that can simulate the actual working conditions of photovoltaic systems was built to verify the accuracy of the model. Based on this, by integrating the complex pyrolysis model and the combustion reaction model, and selecting cotton fibers as the typical combustible indicator substances, as stipulated in the UL 1699 standard, a coupled simulation model for the ignition of solid combustibles by direct current fault arcs was established. The numerical simulation of the entire ignition process of the arc was realized, and the coupling mechanism of heat transfer, mass transfer, and chemical reactions during the ignition process was revealed. The research results of this paper fill a research gap in the numerical simulation of arc ignition caused by DC faults in photovoltaic systems, clarify the fire ignition risk patterns of DC fault arcs under different working conditions, and provide important theoretical support and technical references for the formulation of arc fire prevention strategies and the optimized design of fault arc protection devices for photovoltaic systems and other DC power systems. Full article

Tree contact discharge is a key contributing factor to wildfires caused by medium-voltage insulated conductors. Prolonged abrasion of the insulation layer by branches gradually creates weak points in the insulation. When subjected to lightning strikes, these areas are prone to forming lightning-induced pinholes, which can subsequently trigger partial discharge and even ignition. This study systematically investigates the discharge-induced ignition mechanism for 10 kV overhead insulated conductors in tree contact scenarios by establishing an experimental platform integrated with high-speed imaging, ultraviolet detection, and simulation methods. Three types of typical defects were set up in the experiments: complete insulation abrasion, lightning puncture holes accompanied by localized abrasion, and lightning puncture holes without abrasion. The development process and characteristics of different discharge forms were observed and analyzed. The results indicate that the tree contact discharge ignition mechanism can be categorized into two types: thermal accumulation and direct arcing. The former occurs when insulation abrasion or composite defects exist, where sustained partial discharge or a high-resistance current leads to gradual heat accumulation, resulting in an ignition delay lasting tens of seconds. The latter occurs when only small defects such as lightning puncture holes exist in the insulation layer. A concentrated arc forms due to gap breakdown under high voltage, leading to a millisecond-level ignition process. The study found that different discharge forms produce significantly distinct ablation and carbonization patterns on both the insulation layer and the branch surface, reflecting differences in energy transfer pathways. Simulation analysis further indicated that the thickness of the insulation layer affects the electric field distribution in the tree contact gap, with the initial discharge field strength decreasing as the thickness increases. This study provides experimental evidence and classification guidance for tree contact fault monitoring, insulation condition assessment, and wildfire prevention and control in medium-voltage distribution networks. Full article

This systematic review examines the effect of pre-incident information on public preparedness prior to an emergency or disaster. Preparing members of the public for adverse events can improve self-sufficiency and improve health outcomes, particularly during periods when emergency responders are not immediately available. Twenty-three studies were identified, addressing both natural and human-influenced events. All the studies investigated pre-incident training targeting members of the public rather than specialist responders. The synthesis considered training content, delivery approaches and evaluation methods. The studies included preparation, personal safety, triage, first aid and evacuation in scenarios involving terrorism, fire, earthquake, flood and CBRN events. Pre-incident education generally improves knowledge and intention to act, with higher-intensity and interactive training yielding greater engagement and response. Due to the difficulty of simulating emergencies and disasters, several studies used self-reporting and hypothetical testing, while others attempted to create real-life scenarios. The immediate effects of pre-incident education were generally positive, although many studies tested outcomes theoretically or within a classroom environment. It was also noted that few studies considered retention over the medium to long term; this is a concern as temporal decay may reduce preparedness. This review provides a basis for continued development of public-facing pre-incident education to increase resilience to both terrorist attacks and natural disasters. Full article

The fire resistance and thermal propagation delay of a flame-retardant battery pack case (BPC) were investigated in this study for electric vehicles. Following the Lithium-ion traction battery pack and system for electric vehicles, Part 3: Safety requirements and test methods 31467.3-2015 standards, the BPC specimen was exposed to 500–600 °C for 15 min. Six thermocouples monitored the non-exposed surface, which reached a maximum of 149.7 °C, below the 150 °C limit. No flame occurred during or after heating, and the structure maintained integrity without cracks. The results confirm the flame-retardant BPC’s excellent thermal shielding and demonstrate its potential to enhance EV battery safety by delaying heat transfer and preventing secondary ignition. Full article

This study experimentally investigates the combustion behavior of RP-3 aviation kerosene pool fires (300~800 mm) within a confined space, specifically focusing on the complex interaction between buoyancy-driven plumes and mechanical negative pressure ventilation. By integrating high-precision mass loss measurements with multiple characteristic parameters, this research uniquely characterizes the transition of energy feedback mechanisms under confined suction flow. Results show that ventilation enhances combustion intensity and compresses the fire cycle. For an 800 mm pool, the peak mass loss rate rose by 57.1%, from 16.71 g/s to 26.25 g/s. This enhancement stems from boundary layer thinning, which transitions the combustion from diffusion-controlled to kinetics-controlled. Ventilation also induces severe flame tilt with a non-monotonic trend. The tilt angle peaks at 84° for 600 mm pools but drops to 64° at 800 mm as buoyancy momentum increases. Additionally, an energy contrast of vertical cooling and horizontal heating was observed. Axial peak temperatures decreased by 20%, while downwind thermal radiation flux increased by up to 125%. The ventilation system essentially acts as a directional energy projector, shifting heat loads toward the downwind region. These findings support the optimization of fire safety and detection designs for industrial ventilation systems. This study experimentally investigates the combustion behavior of RP-3 aviation kerosene pool fires (300–800 mm) within a confined space, specifically focusing on the complex interaction between buoyancy-driven plumes and mechanical negative pressure ventilation. By integrating high-precision mass loss measurements with multi-point thermal and imaging diagnostics, this research uniquely characterizes the transition of energy feedback mechanisms under confined suction flow. Full article

Despite advances in engineering, fire safety improvements have plateaued in developed nations, necessitating a reassessment of resource allocation. This study develops a comprehensive fire safety assessment model for the Polish context using the Analytic Hierarchy Process (AHP). A panel of ten experts—comprising fire safety inspectors, State Fire Service officers, and architects—evaluated safety through a two-dimensional framework: the Fire Hazard Index (FHI) and Fire Safety Index (FSI). The results reveal a critical asymmetry: human factors (0.228) and combustible materials dominate the hazard landscape, whereas intelligent AI/IoT systems (0.4133) and passive protection (0.2113) offer the highest potential for safety enhancement. A novel “convergence–divergence” phenomenon was identified: hazard-focused assessments produce convergent priorities across building types (span 0.116), implying universal mitigation needs (e.g., education), while protection-focused assessments yield divergent priorities (span 0.250), justifying targeted investment. Specifically, healthcare facilities (ZL II) require disproportionate protection investment (priority 0.310). The study concludes that sustainable fire safety strategies must combine universal hazard mitigation with targeted technological interventions, offering a data-driven framework for policy optimization in Poland. Full article

Fire incidents in municipal waste management facilities remain a persistent safety issue, complicated by high variability and limited reliability of available data. This study presents a process-oriented evaluation of 86 fire incidents recorded between 2013 and 2022 in the South Moravian Region of the Czech Republic, based on a verified non-public database of the Fire Rescue Service. Most incidents (approximately 76%) were associated with municipal solid waste landfills, confirming their dominant role within the sector. Spontaneous combustion was identified as the most frequent ignition mechanism; however, in nearly 78% of cases, the exact cause could not be conclusively determined, indicating a high level of uncertainty in incident reporting. Key quantitative indicators, including extinguishing water consumption (mean 32 m³, median 10 m³) and affected fire area, exhibited substantial variability, limiting their direct use for quantitative evaluation. To address these limitations, representative fire scenarios were systematically identified and analysed using the ARIA 3 framework in combination with the Bow-Tie methodology. This approach enables the interpretation of fire incidents as disturbances in operational processes and supports the identification of scenario-specific preventive and mitigation barriers. The results show that, despite data uncertainty, incident records provide a robust basis for identifying recurring fire patterns and facility-specific vulnerabilities, supporting scenario-based risk management and informed decision-making in municipal waste management systems. Full article

Fire outbreaks, whether caused naturally or unintentionally, pose serious threats to safety, especially in household environments such as kitchens. Common triggers include overheated personal devices, electrical malfunctions, and unattended cooking appliances. This study aims to develop and enhance an automated fire suppression system designed specifically for residential kitchen settings. The system integrates multiple sensors, photoelectric, ionization, and flame detectors, paired with an Arduino microcontroller to ensure accurate detection and timely activation of a servo mechanism that triggers either a Class A or Class K fire extinguisher. Through controlled testing using both solid and liquid combustible materials, we examined key variables, including sensor placement, height, and nozzle angle. The results from 15 trials per session revealed a correlation coefficient exceeding 0.90 between detection time and distance and the significance level of an analysis of variance of less than 0.05, indicating that increased distance significantly affects response time. The percent error remained below 6.7% across all tests, with strong correlations above 0.8 between combustible material type and the corresponding extinguisher class. This research contributes to the advancement of intelligent fire suppression systems by enhancing detection accuracy, reducing false triggers, and optimizing efficient sensor configurations for residential safety. Full article

The increasing frequency and severity of extreme droughts caused by climate change has emerged as a key risk factor exerting complex effects on the overall national economy through a structure of interconnected industries. The Water Input–Output Linear Programming (WIOLP) model was applied to data from 2015 to 2018 to quantitatively assess the effects of drought-induced water use constraints on production and socioeconomic potential losses. By modeling scenarios in which water use decreased by 10% from 100%, changes in the gross output, the value added, the socioeconomic potential loss, and the shadow price by industry were evaluated. Results showed that socioeconomic potential losses increased nonlinearly, with maximum potential losses of 311,118 billion Korean Won (KRW) in 2015 and 355,260 billion KRW in 2018. The shadow price rose from 7311 to 73,186 KRW/m³ in 2015 and from 3291 to 89,586 KRW/m³ in 2018, confirming that the marginal productivity of water increased exponentially under stricter constraints. Industry-level analysis revealed the largest losses in high water use industries (e.g., agriculture, forestry, fisheries, chemicals, and non-metals), whereas electricity, electronics, and machinery sectors maintained relatively stable production. This study demonstrates that the WIOLP model can empirically analyze nonlinear economic ripple effects under resource constraints, overcoming limitations of conventional input–output and computable general equilibrium models. Full article

To address the strong nonlinearity of aerodynamic loads during projectile exterior ballistic flight and the difficulty in accurately modeling fuze dynamic responses, this paper proposes a data-driven modeling and simulation method for fuze exterior ballistic dynamics. A high-fidelity aerodynamic database covering a range of Mach numbers and angles of attack is constructed based on CFD (Computational Fluid Dynamics) simulations. An MLP (Multilayer Perceptron) neural network is then employed to develop an aerodynamic surrogate model, enabling continuous representation of aerodynamic loads within the given sample space. The results show that, within the data coverage range, the proposed model is able to capture the nonlinear variation in aerodynamic parameters and shows improved prediction accuracy compared with the polynomial fitting method. Specifically, for typical aerodynamic parameters, the RMSE (Root Mean Square Error) is reduced from 5.758 to 0.223, the MAE (Mean Absolute Error) is reduced to 0.099, and the R² (Coefficient of Determination) approaches 1. On this basis, the aerodynamic surrogate model is embedded into a six-degree-of-freedom projectile–fuze exterior ballistic dynamics model via the secondary development interface of ADAMS 2020 (Automated Dynamic Analysis of Mechanical Systems), enabling coupled simulation between aerodynamic loads and multibody dynamics. Comparison with firing table data indicates that, under typical operating conditions, the relative deviation of ballistic parameters is generally better than 94%, demonstrating that the proposed method can reasonably reproduce the projectile exterior ballistic characteristics. Furthermore, based on the coupled dynamics model, the dynamic response characteristics of the fuze moving body during the exterior ballistic phase are analyzed. The results indicate that the axial forward overload of the moving body increases significantly with the initial nutation angle, and the variation in the axial projection of gravity induced by nutation plays an important role in its transient response. The proposed approach provides a useful reference for the dynamic response analysis and safety evaluation of fuzes. Full article