In this study, BS-12 and M-7770 served as foaming agents, whereas three inorganic nanoparticles (NPs) (Al(OH)(3), SiO2, and Mg(OH)(2)) functioned as foam stabilizers. Furthermore, tea polyphenols (TP) and MgCl2 were added separately to prepare nanoparticle-enhanced, highly stable foams. The foaming ability, stability, and rheological properties of the nanoparticle-enhanced foams were measured to explore the variation law of material performance. The results indicate that the SiO2 NPs system exhibits the best foam stabilization performance. It remained in a slow drainage stage at 1800 s and exhibited excellent viscoelasticity. Thermogravimetric analysis (TG) was performed to evaluate the ability of the nanoparticle-enhanced foams to suppress coal spontaneous combustion(CSC). The results demonstrate that the flammability index, combustion stability index, and comprehensive combustion index of nanoparticle-enhanced foams containing TP are significantly reduced compared with raw coal. Consequently, these foams can markedly inhibit the oxidative progress of CSC. Finally, the fire-extinguishing performance of different nanoparticle-enhanced foams was evaluated via small-scale fire suppression simulation tests. The fire temperature curves of T-2#, T-3#, and M-6# decreased sharply and remained low (<100 degrees C), with no re-ignition observed. Their fire-extinguishing performance was superior to that of water-based foams and MgCl2 solution. These findings confirm that the SiO2 nanoparticle-enhanced foam system exhibits excellent stability, resistance to shear deformation, and both fire-extinguishing and flame-retardant capabilities. This provides both direction and theoretical support for applied research into efficient fire prevention and suppression technologies.

Solid-state metal batteries promise next-generation energy storage with inherent safety and high energy density. However, instability at grain boundaries and surfaces critically hinders practical deployment in solid polycrystalline ion conductors. This work proposes a dual-interface fluorination strategy through the incorporation of fluoride-based grain boundary phases in solid electrolytes to simultaneously address these issues. The resulting NZSP-MgF2 electrolyte exhibits a low electronic conductivity of 6.0 & times; 10-9 S cm-1 and a widened bandgap, effectively suppressing the formation and growth of internal dendrites. Meanwhile, the interfacial contact impedance of the ceramic electrolyte against the metallic Na electrode is significantly reduced to 11 Omega cm2. Crucially, the fluorinated polycrystalline Na3Zr2Si2PO12 ceramic electrolyte retains exceptional stability even after 30 days of exposure to air: symmetric sodium metal cells still exhibit low interfacial contact impedance (12 Omega cm2), high critical current density (1.0 mA cm-2), and stable cycling over 1100 h at 0.2 mA cm-2. Furthermore, full cells paired with Na3V2(PO4)3 cathode demonstrate outstanding electrochemical performance with a capacity retention of 98.1% after 2000 cycles at 2 C. This work provides a general strategy to enhance air stability, dendrite suppression, and electrode compatibility of polycrystalline electrolyte, promoting the practical realization of solid-state metal batteries.

The preparation of energetic composites has long been challenged by the need to balance uniform dispersion of high-energy components with preservation of their structural integrity. Conventional mixing methods are particularly problematic for systems with large density contrasts: excessive shear forces promote particle fragmentation, whereas insufficient mixing intensity results in non-uniformity, both of which compromise performance reliability. In this study, tungsten powder (W), barium chromate (BaCrO4), potassium perchlorate (KClO4), diatomaceous earth, and fluororubber were combined to formulate tungsten-based delay compositions using three approaches: resonant acoustic mixing, mechanical ball milling, and hand mixing. The mixed samples were characterized by morphology, particle size distribution, mixing uniformity, combustion performance, and thermal properties. Discrete element simulations were further employed to elucidate the underlying mechanisms of resonant acoustic mixing and ball milling. The results demonstrate that resonant acoustic mixing achieves uniform blending while preserving particle morphology, yielding a delay time scatter coefficient as low as 1.20%. By contrast, ball milling caused extensive fragmentation, leading to double-peak DSC profiles characteristic of stepwise reactions and incomplete combustion. Hand mixing preserved particle shapes but yielded poor uniformity and inferior delay accuracy. Overall, this study demonstrates that particle morphological integrity and mixing uniformity play crucial roles in controlling combustion behavior, and highlights the superior performance of resonant acoustic mixing technology in processing high-density-gradient energetic composites.

Precise control over crystal morphology is critical for energetic materials, as it governs packing behavior, thermal stability, and interfacial reactivity. However, morphology regulation of primary explosives remains challenging, particularly when simultaneous spheroidization and densification are required. Herein, nickel (II) tricarbohydrazide perchlorate (GTN) is employed as a model system to demonstrate a synergistic multiscale interfacial regulation strategy enabled by a binary surfactant system. By integrating maltodextrin (MD) and carboxymethylcellulose sodium (CMC), dense spherical GTN crystals are constructed through the cooperative coupling of molecular-level facet adsorption and mesoscale spatial confinement. Real-time crystallization monitoring, microscopic characterization, and first-principles calculations collectively elucidate the underlying growth and assembly mechanisms. The results reveal that MD selectively adsorbs on GTN crystal facets via hydrogen bonding, promoting intercrystalline adhesion and densification, while CMC generates a coordination-induced nanofiber network that guides spherical assembly. The synergistic interplay between these interfacial effects enables hierarchical crystal organization that cannot be achieved using single surfactants. As a consequence, the dense spherical crystals exhibit significantly improved bulk density, flowability, and thermal stability, alongside enhanced structural robustness under elevated-temperatures. This work establishes a generalizable interfacial regulation paradigm for hierarchical morphology control of primary explosives and provides insights applicable to a broad range of energetic materials.

To quantitatively elucidate the effects of overload current on the ignition and burning hazards of polyethylene-insulated wires, 2.5 mm2 polyethylene-insulated copper wires used commercially were tested in an electrical fire fault simulation system. Experiments were conducted to study the evolution of overloads, ignition, and burning. The entire process, from insulation smoking and ignition to sustained burning and final extinction driven by wire fusing, was recorded using synchronized digital and high-speed imaging. Video-based measurements were used to extract the following: smoking emission duration, ignition time, burning duration, maximum flame height, and segmented flame width. The results show that stable ignition and sustained burning occur when the overload current is greater than or equal to 180 A. As the current increases, ignition occurs earlier, while the smoking stage becomes shorter but exhibits nonmonotonic fluctuations. The burning duration shows a staged response. It first increases, then decreases toward a relatively stable level. This reflects the competition between enhanced Joule heating and accelerated wire melting and fusing. Maximum flame height and segmented flame width vary nonmonotonically with current, and the segmented flame width peaks at 200 A. A multi-indicator fire hazard evaluation framework was established and an entropy-weight TOPSIS method was applied to integrate the quantification and ranking. The overall fire hazard is greatest at 200 A. These findings provide experimental insight into overload-induced ignition and combustion behavior and contribute to a quantitative understanding of fire hazard evolution in overloaded electrical wires.

Nano-thermite energetic films were suited to microscale laser ignition, but weak NIR absorption and low energy-use efficiency still limited practical use. Herein, we addressed these limitations by integrating Ti3C2 into flexible Al/Bi2O3 films via Direct Ink Writing (DIW). Experimental characterizations and theoretical calculations (Gibbs free energy, Bader charge analysis) indicated that Ti3C2 acted as a multifunctional regulator: it enhanced NIR absorption via localized surface plasmon resonance (LSPR), accelerated heat conduction, and tailors thermite reactions via a three-stage pathway (preheating, reaction and product transfer). Ultimately, by tuning the Ti3C2 content, the laser ignition threshold was reduced by 60.8 % and the photothermal conversion efficiency was increased to 41.43 % at 10 wt%, the reaction onset temperature was decreased by 40 degrees C and the maximum flame propagation/pressurization performance was achieved at 1 wt%, and the total heat release was nearly tripled at 5 wt%, indicating a comprehensive optimization of the combustion behavior. This work established a Ti3C2 paradigm for coupling photothermal conversion with chemical energy release, enabling low-threshold, high-response micro-igniters and miniaturized devices.

Hypothesis: Tetrasiloxane-based surfactants with high surface activity and low lipophilic groups are ideal candidates for designing new-generation fluorine-free foams. Shortening the alkyl end caps of tetrasiloxane-based surfactants theoretically drives the molecules from a bolaform conformation to an upright and extended conformation at the air-water interface, thereby increasing the monolayer density and enhancing surface activity and foam stability. On this basis, blending the cationic tetrasiloxane-based surfactant featuring short alkyl end caps and a nonionic siloxane surfactant weakens intermolecular electrostatic repulsion to construct a high-density molecular layer, which is expected to enhance film-forming ability and foam oil resistivity. Experimental: Three synthesized tetrasiloxane-based surfactants with varying alkyl end caps lengths were blended with a commercial trisiloxane surfactant to construct binary systems. Control groups without tetrasiloxane-based surfactants were established for comparison. Subsequently, we investigated their interfacial properties, film-forming ability, and oil resistivity on standard fuel (cyclohexane). Findings: Mixed systems containing tetrasiloxane-based surfactants with shorter alkyl end caps exhibit enhanced surface/interfacial activity and foamability. Shortening the alkyl end caps of tetrasiloxane-based surfactants from C10 to C6 turns the system from non-spreading to spreading on cyclohexane, whereas further shortening to C2 only marginally increases the spreading area. In the presence of cyclohexane, foams of tetrasiloxane-based surfactant with shorter alkyl end caps systems show stronger oil resistivity. Thermodynamic theory and oil--film interaction further verify that this behavior is jointly determined by the isolated water film between the film-forming foam and oil, thermodynamic stability and oil-phase expulsion. In contrast, these characteristics are absent in the control groups.

Alkali metal-ion batteries, such as lithium-ion and sodium-ion batteries, have been widely recognized by both academia and industry for their high energy density, long cycle life, low self-discharge rate, and environmental friendliness. Theoretical calculations are crucial in elucidating the energy storage mechanism of alkali metal-ion batteries and in designing the next generation of high-performance energy storage systems. This article reviews the application of theoretical calculations in alkali metal-ion batteries. These calculations are instrumental for experimental researchers in understanding the microscopic design of electrode materials, optimizing various interfaces and electrolyte structures, and clarifying ion and electron transport behaviors as well as electrochemical reaction mechanisms. Specifically, researchers typically calculate the reduction reactions, charge state changes, and structural changes of cathode materials to predict their electrochemical reactivity and optimize their performance and stability. Calculations and simulations of alkali metal batteries focus on ion transport dynamics within the electrolyte, including energy level distribution, solvation structure, and molecular dynamics simulations. Analyzing oxidation reactions, ion diffusion, and volume changes in various alkali metal-ion battery anode materials enables the screening and design of new anode materials with superior electrochemical properties. This review also discusses the challenges of applying theoretical calculations in alkali metal-ion batteries and provides an outlook for future research. Critical insights are offered for advancing research paradigms that integrate theoretical and experimental approaches in the development of energy storage electrode materials.

Surface peeling defects caused by inclusions are commonly observed in pickling coils of commercially pure titanium (CP-Ti) ingots, which deteriorate the surface quality of the rolled products. In this work, inclusions in the CP-Ti ingots melted by Electron Beam Cold Hearth Melting (EBCHM) and Vacuum Arc Remelting (VAR) are extracted by the electrolytic extraction, and their three-dimensional morphology, type, and size distribution are analyzed by using SEM. Moreover, the origins of the various inclusion types were also investigated. Besides, a dissolution model for titanium oxides is developed to simulate the dissolution of TiO2. The results show that most of inclusions are titanium oxides, accounting for 89 % of the total. The rest is a small amount of Al2O3, composite inclusions, and high-density inclusions containing W. Their sizes predominantly range from 80 to 300 mu m. The total inclusion content measured in the VAR ingot is 51 % higher than that in the EBCHM ingot. During the dissolution of titanium oxides, the phase transformation occurs on the surface, leading to the formation of a thin layer of Ti3O5. In the EBCHM process, it takes 466s for the 500 mu m TiO2 particle to be completely dissolved at 1720oC. The dissolution rate of inclusions is enhanced with the high temperature, but it remains almost constant with the size and time. Therefore, a low melting speed and high temperature process can promote the inclusion dissolution.

Nanoparticles (NPs) exhibit enormous application potential in fluorine-free foam. However, the effects of NPs on stability, spreading ability, and fire suppression performance of foam remain incompletely understood. In this study, a fluorine-free foam was constructed using non-ionic silicon surfactant CoatOsil-77, anionic hydrocarbon surfactant OT-75, and hydrophilic silica NPs. The interaction between NPs and surfactants, as well as the stability, spreading ability, and fire suppression performance of the foam, was investigated. Results indicated that as NP concentration increased, dynamic surface tension (DST), conductivity, absolute value of Zeta potential, polydispersity index (PDI), and foamability of the foam dispersion decreased, whereas Z-average diameter and viscosity increased. NPs delayed foam drainage and improved stability. 1.95% NPs exerted a negative impact on foam spreading ability. In the linear spreading stage, 1.95% NPs reduced the foam spreading rate by 16.54%. 1.95% NPs enhanced the foam fire suppression performance. The foam containing 1.95% NPs had a fire extinguishing time of 64 s and a burn-back time of 679 s. Compared with the foam without NPs, the fire extinguishing time was shortened by 31%, and the burn-back time was increased by 84%. The results of this study can provide guidance for the application of NPs in fluorine-free foam.

Multifunctional protective textiles that resist fire, suppress bacterial contamination, and enable the conversion of chemical warfare agent simulants are highly desirable for harsh operational environments. Herein, a hybrid coating was constructed on cotton, polyester (PET), and polyester/cotton blended fabrics (T/C) using a two-step hot-pressing route. A Zn-based dual-ligand metal organic framework (MOF) layer was first grown in situ to provide flame-retardant catalysis and antibacterial Zn2+ activity, followed by the introduction of amino-functionalized polyhedral oligomeric silsesquioxane (POSS) and immobilization of Tetrakis (4-carboxyphenyl) porphyrin (TCPP) through interfacial interactions to form a robust hybrid network. The resulting fabrics showed substantially improved flame-retardant performance, with the limiting oxygen index (LOI) of cotton increasing from 17.7% to 44.8%, together with high char yield. They also exhibited broad-spectrum antibacterial activity, with more than 99.9% inhibition against Staphylococcus aureus and Escherichia coli, and enabled light-driven degradation of chemical warfare agents (2-chloroethyl ethyl sulfide, CEES), achieving approximately 95% conversion within 10 min. In addition, all coated fabrics retained more than 90% of their initial LOI values after 30 laundering cycles, indicating good laundering resistance of the flame-retardant performance. This work offers a scalable strategy for integrated multifunctional protective textiles.

Hot particles generated by arc faults are significant ignition sources to Wildland-Urban Interface (WUI) fires. Knowing the characteristics of hot particle distribution is one of the most important parameters to the establishment of safe zones for the prevention of WUI fires. However, the related research is limited. To fill this gap, a comprehensive model which takes the wind as the reference frame was built based on dynamic equations in this paper. In addition, an experimental device was set up to prove the correctness of a special case in this model successfully. Finally, the machine learning was also used to predict the farthest landing distance in this specifical condition. The results predicted by model suggest when there is no wind and the shape of the splashed hot particles is spherical, as the height of the arc increases, the farthest landing distance of the splashed hot particles gradually increases, and eventually stabilizes within a certain range. The main factor determining the farthest landing distance of the splashed hot particles is transformed from the arc height to the air resistance. All these predicted results are consistent with the experimental results obtained. The method proposed by this model, which uses wind as the reference frame, can significantly reduce the computational load in actual operations, providing a reference for subsequent development of more complex kinematic models. Furthermore, by incorporating studies on the ignition thresholds of hot particles in complex scenarios, this kinematical framework can be extended to provide more support for fire safety engineering.

The compressed air foam system (CAFS) has demonstrated significant potential for use in combating flammable liquid fires at ultra-high voltage (UHV) substations in high-altitude environments. However, the system performance and fire extinguishing performance of CAFS at high altitude are unclear. In this study, the performance of the air compressor, water pump, and CAFS at different altitudes was studied. Besides, the fire extinguishing performance of CAFS at different altitudes, different system flow rates, and different expansion ratios (ERs) was also studied. Results indicated that as the altitude increases, the gas pressure decreases, the pressurization time of the air compressor increases, and the pressurization efficiency decreases. The flow and outlet pressure of the water pump increased with increasing altitude. Besides, the fire extinguishing performance of the CAFS is improved as the altitude or the system flow rate increases. The optimal parameter settings for CAFS with excellent system performance and fire extinguishing performance at high altitude are 11.4 L/min of the system flow rate and 8 times the ER. The results of this paper can guide flammable liquid fire prevention and control in UHV substations at high altitude.

The development of fluorine-free foam with silicone surfactant mixtures as the core has significant application potential, yet the comprehensive performance of such mixtures remains not fully elucidated. In this study, it is hypothesized that specific synergistic interactions between distinct silicone surfactants in a binary system can significantly enhance foams for heavy oil fire suppression. To verify this hypothesis, five silicone surfactants (SiS1, SiS2, SiS3, SiS4, and SiS5) were selected to prepare 10 binary composite systems. Systematic characterizations of surface/interfacial properties, film-forming ability, and foamability were conducted. Results indicated that binary compounding significantly altered the performance of surfactant mixtures. Notably, the SiS1/SiS3 mixture exhibited the optimal comprehensive performance, forming a continuous liquid film and maintaining exceptional foam stability by effectively delaying foam drainage and coarsening. In a typical transformer oil fire test, the optimized formulation, stabilized by 0.05 wt% xanthan gum, achieved an exceptional fire-extinguishing time of 63 s and a burn-back time of 543 s, successfully outperforming conventional aqueous film-forming foam. SiS1/SiS3 is proven to be an ideal core component, and this work provides empirical data and practical formulation strategies for the development of high-performance fluorine-free foams.

A novel internal-external dual-modification strategy systematically optimizes the structure and interfacial properties of LATP-based solid-state electrolytes.

Space propulsion technology opens fascinating possibilities for exploring more distant regions of the universe. As a promising source of propulsion systems, hypergolic propellants can generate self-sustaining combustion upon contact with oxidizers, demonstrating significant superiorities in their system simplicity, cost-efficiency, restart capability, and precise thrust control. However, currently used hydrazine-based fuels and their liquid engine system have high toxicity and complex loading issues, making them unable to meet the growing demand for simplicity and controllability of advanced propulsion systems. The development of advanced hypergolic fuels has recently focused on metal-coordinated materials, with flexible metal-organic architectures providing superior tunability over traditional alternatives. The diversity in metal centers, organic ligands, and coordination geometries offers unprecedented opportunities for tailoring ignition behavior and energy release processes. Moreover, the well-defined atomic structures of these materials could provide an ideal platform for elucidating structure-activity relationships, supporting the rational design of high-performance hypergolic propellants through coordination chemistry. In this review, we document advancements in the field of metal-coordinated hypergolic materials, encompassing metal complexes, metal clusters, metal halides, and metal organic frameworks, focusing on understanding the crucial factors that regulate hypergolic activity. Through a critical analysis of the development of advanced metal-coordinated hypergolic materials, including structure design, machine learning assisted structure optimization, mechanism exploration, and practical adoption, this review offers valuable insights for future research in this field.

Thermite materials have attracted considerable attention due to their ability to release a large amount of heat instantaneously during the reaction. Traditionally, the combustion performance and energy release efficiency of thermite have been enhanced by modifying it with additional materials. This study employs an innovative approach regarding a CuWO4 composite metal oxide containing two metal elements was prepared, and Al was combined with CuWO4 (copper tungstate) in five different equivalent ratios using ultrasonic mixing technology. The experimental results show that the combustion performance and energy release characteristics of Al/CuWO4 are optimal when the equivalent ratio is 1.5. Further comparisons reveal that this sample has almost the same ignition delay time as the Al/CuO/WO3 mixture with the same equivalent ratio. However, during combustion, the flame of Al/CuWO4 Phi 1.5 (where: Phi = 1.5, Phi - equivalence ratios) is more stable and can produce a higher temperature; thus, it may be that the Al/CuWO4-based thermite holds broad application prospects in various fields of useful materials, including: propellants, welding agents, and pyrotechnic products.

While nanoparticles (NPs) are known to enhance the rheological properties of firefighting foams, the impact of different NPs types on the foam thermo-rheological properties has remained unclear. Short-chain fluorocarbon and hydrocarbon surfactants, and three types of NPs (SiO2, Al(OH)3, and (3-Al2O3) were used to prepare the foams. The interactions between NPs and surfactants, as well as their effects on foaming ability, foam stability, and foam thermo-rheological properties, were analyzed. Results indicated that NPs can form aggregates with surfactant molecules, thereby affecting surface tension, pH value, conductivity, zeta potential, viscoelasticity, and viscosity of foam dispersion. NPs can reduce the initial foam height of the foam dispersion from 340 mL to 250-260 mL, and significantly decrease the foaming ability. All three NPs could significantly delay foam drainage and enhance foam stability. At 45 degrees C, the NPs can decrease foam viscosity and viscoelasticity. The thixotropy of all foams at 45 degrees C showed different trends, and the foam with Al(OH)3 NPs showed the best thixotropic structure recovery. Hysteresis behavior at 45 degrees C of the foam with Al(OH)3 NPs decreased, but increased in the foam containing SiO2 and (3-Al2O3. In general, all three NPs could enhance the foam stability and foam thermo-rheological properties, with Al(OH)3 demonstrating the strongest capability. This study can provide theoretical support for the development of firefighting foam stabilized by NPs.

An ion chromatography (IC) method was developed for the purity determination of the poorly soluble energetic coordination compound lead NTOate (lead(II) salt of 3-nitro-1,2,4-triazol-5-one). To overcome the limitations of conventional ethylenediaminetetraacetic acid (EDTA) titration and chromatographic approaches, a simple pretreatment strategy was established in which a trace amount of acetic acid was introduced to facilitate dissolution of lead NTOate, enabling subsequent determination of the NTO2- ligand anion by IC. Under the optimized conditions, the method exhibited a linear range of 0.5-100 mg L-1 with excellent linearity (R2 = 0.9996), together with low detection limits and satisfactory accuracy, precision and repeatability. The purity results obtained for production samples were consistent with those determined by EDTA titration while avoiding its complex operational procedures. The proposed IC method enables rapid and reliable purity determination in a single measurement and provides an effective analytical approach for the quality evaluation of lead NTOate and related energetic coordination compounds.