Search Results (509)

Armed conflict affects built heritage through immediate damaging actions and subsequent deterioration, but these processes must be distinguished from damage manifestations and affected components. This study compares 25 documented asset-damage records from a source-bounded purposive frame of 30 candidates across 11 countries or territories. Conflict context and attribution, physical actions, damage manifestations, affected components and cumulative conditions are coded at separate analytical levels. Physical Loss Class (PLC 0–4) is used only as a unit-dependent index for comparison within this sample. The revised coding records explosive or projectile action in 23 cases, fire or thermal exposure in 6 cases, and mechanical dismantling in 3 cases; actions overlap. Reduced-unit, overlap-reduced and building-only subsets expose the sensitivity of these descriptions to the analytical scale. Three structured contrasts under limited conditions illustrate differing recorded recovery states without matching cases or isolating causal effects. Surviving evidence, access, material compatibility, resources, function and documented authority provide contextual considerations for intervention. The reconstruction–recovery gap is retained as a provisional qualitative decision tool derived from the literature and case evidence. Missing evidence and original wartime fabric loss do not, by themselves, establish a post-reconstruction deficit. A provisional triage sequence links preparedness, separate conflict/safety/access reviews, feasible protection or documented deferral, and subsequent reassessment. International institutional reporting and World Heritage projects dominate the sample; added residential, community and independent technical research broadens interpretation without removing that selection bias. No assessment model is validated. Full article

This manuscript presents the theory and experimental validation of low- and medium-temperature deicing technology that advances the recently developed Ice Cavitation Deicing (ICD) method. Conventional high-temperature ICD (HTICD) efficiently removes ice by explosively vaporizing a thin interfacial melted layer but operates at heating rates above 10⁶ K/s, high voltage, and maximum temperatures exceeding 400 °C. This study develops Low-Temperature and Medium-Temperature Ice Cavitation Deicing (LTICD and MTICD), extending ICD into the previously unexplored intermediate heating-rate regime. Analytical modeling based on energy conservation, transient heat diffusion, water thermodynamics, and thermal-stress analysis was combined with finite-element simulations and experimental testing. Several foil materials were evaluated over heating rates of approximately 10⁴–10⁷ K/s using capacitor banks of 0.1–35 mF. Experiments demonstrated effective removal of thick and thin ice at cavitation temperatures of approximately 120–200 °C, substantially below those of HTICD. The lower operating temperatures and heating rates reduce thermal stress, voltage, and current, enable practical low-voltage electrolytic capacitors, and expand the range of suitable materials. Thus, LTICD and MTICD provide a lower-temperature, more practical electrical architecture for future aircraft ice-protection systems. Full article

Biomethane recovery from lignocellulose is limited by the recalcitrance of the fibre matrix, which pretreatment can relieve. Thermal pretreatment is usually optimised through temperature, whereas the residence time of hydrothermal treatment is seldom isolated as an independent variable, and rarely without added acid. Willow (Salix viminalis) and maize silage (Zea mays) were treated by microwave autohydrolysis with explosive decompression at 130 °C, using residence times of 5, 15 or 25 min against an untreated control, and assessed for solubilisation, by-products, methane potential, kinetics and net energy balance. Relative to the control, the 25 min treatment raised methane potential by 189% in maize silage (to 384.8 ± 21.4 NmL CH₄ g⁻¹ VS) and by 129% in willow (to 333.5 ± 14.2 NmL CH₄ g⁻¹ VS), reaching 72–74% of the theoretical maximum. Silage gained 78% at the first treated point (5 min dwell), whereas willow showed no significant gain before 15 min; in willow, the methane gain tracked continuously released xylose (r = 0.996) rather than the early COD or glucose burst. Furanic by-products remained very low; indicative concentrations and total phenolics stayed below reported methanogenesis inhibition thresholds for phenol (direct equivalence between total phenolics and pure phenol not assumed), so yield rose monotonically without turnover. The incremental energy balance stayed negative; the estimated incremental energy recovery reached 74% of the calculated input for willow and 97% for silage at 25 min. Full article

Thermal runaway propagation in large-capacity battery energy storage systems can be driven by casing conduction, vented products, and pack-level thermal coupling. This study experimentally evaluated whether a static dielectric-liquid boundary can prevent propagation between 314 Ah rectangular cells. Three-cell modules were tested in air and in two liquids at relative immersion heights of 10–20 mm, followed by two non-circulating 1P52S pack tests. Propagation was assessed using trigger-cell temperature and venting, adjacent-cell voltage and venting, and post-test state. Under AIR-0, adjacent-cell voltage fell to 0 V and propagation occurred; the trigger cell reached its primary peak of 613 °C at 1560 s, followed by a secondary-heating maximum of 971 °C at 1893 s. All six immersed module tests maintained stable adjacent-cell voltages, with no adjacent-cell venting or propagation, while trigger-cell maximum temperatures were 403–498 °C. Using a common window from trigger-cell venting to its primary peak, the apparent equivalent surface-averaged heat-flux indicator was 31.2 kW/m² in AIR-0 and 22.5–29.3 kW/m² under immersion, corresponding to a reduction of approximately 6.1–27.8%. In both pack tests, no fire, explosion, adjacent-cell venting, or pack-level propagation occurred. Under the tested module and pack configurations, no propagation from the trigger cell to adjacent cells was observed with static immersion, supporting its potential as a passive safety boundary for large-capacity battery storage systems. Full article

Waterborne polyurethane (WPU) has emerged as one of the most promising environmentally friendly coating materials owing to its low volatile organic compound (VOC) emissions, excellent film-forming ability, good adhesion, and versatility in formulation. However, WPU suffers from several intrinsic limitations including inadequate thermal stability, modest mechanical strength, poor flame retardancy, and a lack of inherent antibacterial activity. To address these deficiencies, phosphorylated microfibrillated cellulose (PMFC), prepared from beech wood sawdust via sequential steam explosion, phosphorylation, and superfine grinding, was employed as a substrate for in situ silver nanoparticle (AgNPs) synthesis and subsequent incorporation into WPU via aqueous blending and solvent casting. PMFC functions through a combined mechanism: the hydroxyl and phosphate groups coordinate Ag⁺ ions, providing nucleation sites, while the nanofibrillar network provides steric stabilization against post-synthesis aggregation. The influence of AgNPs loading (1–10 wt% relative to PMFC at a fixed 1 wt% PMFC content) on the morphology, antibacterial activity, silver release behavior, thermal stability, flame retardancy, and mechanical properties of the resulting composite films was comprehensively investigated using free-standing composite films as a model system. At the optimal Ag loading of 5 wt%, the composite exhibited strong antibacterial activity against Escherichia coli with silver release below 1.15 ppb after 96 h, while tensile strength and Young’s modulus increased by 80% and 298%, respectively, relative to neat WPU. At high Ag loadings (70–80 wt%), the composites achieved conductive-level surface resistivity (~3 log Ω) through percolation network formation, demonstrating antistatic functionality. This study provides an effective strategy for fabricating WPU composite films with combined antibacterial, mechanical reinforcement, and antistatic capabilities. Full article

Two-stage anaerobic digestion (TSAD) is an alternative to single-stage anaerobic digestion, separating hydrolytic–acidogenic and methanogenic phases to improve stability, organic matter degradation, and methane production. This review examines TSAD for co-digestion of sewage sludge (SS) and the organic fraction of municipal solid waste (OFMSW), emphasizing performance, scale-up challenges, digestate intensification, and nutrient recovery. TSAD can increase methane production by 25–50% compared with single-stage systems, while volatile solids removal can reach 87–93% depending on substrate type, temperature regime, hydraulic retention time, and organic loading rate. However, improvement remains variable and depends on substrate biodegradability, reactor configuration, and process control. Beyond methane recovery, the review highlights valorizing digestate as a secondary resource. Digestate post-treatment technologies, including thermal hydrolysis and steam explosion, report methane improvements from 26% to more than 300%, although energy demand and economic feasibility remain constraints. Nitrogen recovery technologies, including ammonia stripping and membrane contactors, can achieve efficiencies above 80–95% under optimized conditions, while phosphorus may be recovered through struvite precipitation, calcium phosphate recovery, or biochar-based pathways. Future TSAD development should integrate biological conversion, digestate recirculation, nutrient recovery, techno-economic assessment, and life-cycle evaluation to support circular, resource-efficient organic waste treatment systems. Full article

Accurate high-temperature field characterization is important for explosion diagnostics, laser–matter interaction, combustion monitoring, and related thermal processes. This work presents an integrated thermometry framework combining fiber-optic spectrometry with monochrome imaging. Its central contribution is not a new multispectral principle or optimization algorithm, but an integration-time-dependent radiometric calibration framework coupled with representative spectral-emissivity transfer under clearly stated applicability conditions. Its central element is a three-parameter radiometric calibration model in which camera integration time is explicitly included, so that radiance conversion can be performed across the experimentally calibrated integration-time range without repeating a separate fixed-exposure calibration for each setting. Multiwavelength spectral radiance is used to jointly retrieve temperature and a continuous, second-order polynomial emissivity function with a genetic algorithm serving as the global optimizer. The emissivity function obtained from a representative spectral sampling region is then transferred to the imaging model for pixelwise temperature inversion; this step assumes that the material and surface state are sufficiently uniform over the region to which the function is applied. The method is examined using steady-state tungsten–halogen-lamp measurements with nominal color temperatures of 2200–2800 K and a transient laser-heated 316L stainless-steel case. Agreement with a Wien-based estimate is used as an internal spectral-consistency check rather than as an independent traceable accuracy validation. In the transient case, the retrieved spectral-field-of-view temperature increased from 2311.9 to 2398.5 K over 50–60 s, and the reconstructed images reproduced the corresponding increase in the central high-temperature region. The present results demonstrate the feasibility of coupling integration-time-dependent calibration with measured spectral-emissivity transfer for two-dimensional temperature reconstruction, while the achievable absolute accuracy remains subject to detector linearity, emissivity-model validity, spatial emissivity uniformity, radiometric calibration, and independent reference validation. Full article

This study quantitatively investigates the effects of methane concentration and sealed/vented boundary conditions on the transient pressure, temperature, and propagation characteristics of methane–air explosions in a reduced-scale goaf-like enclosure. Experiments were conducted in a 0.5 m³ rectangular chamber at methane concentrations of 8%, 10%, and 12%, with pressure and temperature measured synchronously under sealed and vented boundary conditions. Numerical simulations were further performed to examine explosion-propagation characteristics. The sealed boundary condition produced substantially greater pressure and thermal accumulation within the chamber than the vented condition. The highest measured local pressure and temperature were 0.711 MPa and 552.46 °C, respectively, at 12% methane. The maximum pressure rise rates under the sealed condition were 3.00, 3.00, and 6.25 MPa/s at 8%, 10%, and 12% methane, respectively. Under the vented condition, the pressure and temperature responses exhibited a pronounced non-monotonic dependence on methane concentration, with the strongest measured response among the tested concentrations occurring at 10% methane, close to the stoichiometric composition. At this concentration, the highest measured local pressure and temperature reached 0.341 MPa and 373.05 °C, respectively, while the representative maximum pressure rise rate at P2 reached 5.70 MPa/s. Numerical results further indicate that venting reduces pressure and thermal accumulation within the chamber but can transfer high-temperature, high-velocity explosion products into the connected airway. These findings indicate that methane-explosion hazards in goaf–roadway systems should be evaluated by considering both peak loads and transient energy-transfer characteristics under different boundary conditions. Full article

The investigation of structure and properties in the intermetallic compound Ni₃Al, synthesized via self-propagating high-temperature synthesis (SHS-compaction) under quasi-volumetric thermal-explosion conditions, is presented in this study. The effect of preliminary pressure gradient in the range of 33–136 MPa on the quantitative properties of the final microstructure has been identified. It was demonstrated that a preliminary pressure of 115 MPa suppresses secondary recrystallization via grain boundary pinning by Al₂O₃ particles, which halves the average grain size to 7–11 μm. Consequently, a pronounced room-temperature yield strength enhancement was documented, following the grain boundary strengthening mechanism. High-temperature testing up to 1000 °C revealed an anomalous yield strength peak attributable to the activation of Kear–Wilsdorf barriers. A comprehensive fractography analysis shows a profound transition from intergranular brittle fracture to a mixed mechanism featuring dimple rupture at extreme temperatures. This work illustrates SHS-compaction as a highly efficient powder metallurgy approach for synthesizing structural intermetallics. Full article

Transition joints between lightweight aluminum alloys and high-strength steel are widely employed in the transportation industry, and especially in shipbuilding, as intermediate inserts between structural components made of dissimilar metals. While traditional fusion welding presents considerable difficulties in joining such metals, explosive welding is particularly suitable for producing thick plates with large contact surfaces between aluminum and steel. The process setup and the various parameters involved have been described in several articles, as also documented by some recent overviews. However, there has been no review of the most recent papers specifically dealing with the metallurgical characteristics of these interfaces, as well as with their mechanical properties. Thus, the present article aims to fill this gap by outlining a review on the state of the art to correlate the process parameter setting, interface characteristics, and weldability of aluminum/steel transition joints, and then focusing on the most relevant studies concerning the mechanical behavior under static and fatigue conditions of trimetallic joints (Al alloy/commercially pure Al/structural steel) for shipbuilding applications. The effects of welding-induced thermal fields during structural joint insertion are also taken into account, and the most recent proposals for strategies to improve mechanical performance are examined. Full article

To investigate the elevated-temperature performance of Ultra-High-Performance Concrete (UHPC) and Ultra-High-Performance Geopolymer Concrete (UHPGC), a systematic comparative study was conducted at 800 °C. This study examined the effects of the steel fibre geometry (micro and hooked-end) and dosage (1.5% and 2.0%) on mass loss, crack propagation, residual compressive, flexural, and tensile strengths, and chemical evolution following a 24 h pre-drying protocol to mitigate explosive spalling. The results demonstrate that UHPGC exhibits superior thermal stability and residual mechanical performance compared with UHPC after high-temperature exposure. Among all mixtures, the UHPGC mixture reinforced with 2% micro steel fibres (UHPGC-M2) achieved the highest residual compressive strength (30 ± 0.4 MPa, corresponding to 25% strength retention compared with 21% for the equivalent UHPC mixture), the lowest post-exposure crack width (0.08 mm), and the highest tensile strength retention (17.9%). Micro steel fibres were more effective in controlling crack propagation and preserving peak load capacity, whereas hooked-end fibres contributed more significantly to post-peak ductility. Chemical analysis revealed substantial chemical changes in both systems after exposure to 800 °C. However, UHPGC exhibited lower mass loss (4.8%) and greater residual performance. These findings establish micro steel fibre-reinforced UHPGC as a sustainable and high-performance material for fire-resistant structural applications. Full article

Silver (Ag)-based conductive coatings are widely used in electrical contacts due to their excellent electrical conductivity, low contact resistance, good thermal stability and oxidation resistance, although their susceptibility to sulfidation and environmental corrosion is a concern under certain service conditions. In recent years, significant progress has been achieved in both the manufacture and performance optimization of Ag-based coatings to satisfy the demanding requirements of modern electrical and electronic systems. This review summarizes recent advances in fabrication techniques and processing parameters for Ag-based coatings, including electroplating, electroless deposition, magnetron sputtering, electrospark deposition, thermal spraying, and electrical explosion spraying on metallic substrates, particularly on copper and steel substrates. More attention is given to microstructural design strategies, such as the incorporation and homogeneous dispersion of reinforcement or solid lubricant phases within the Ag matrix, to enhance contact reliability and operational endurance. The performance of Ag-based coatings is analyzed in terms of their physical, chemical and mechanical properties, electrical contact resistance, friction and wear behavior, arc erosion resistance, and environmental durability under different service conditions. Key challenges, including coating degradation under high electrical loads, mechanical wear, and corrosive environments, are highlighted. Future research directions are outlined, focusing on multifunctional coating structures that enhance surface performance and ensure the long-term durability of electrical contacts. Full article

This article is a continuation of research conducted by the authors on the effects of fire on cementitious composites and presents findings of an investigation into cement mortars that incorporate monofilament (I) and multifilament (F) polypropylene fibres following exposure to temperatures between 100 and 600 °C. Research was undertaken to examine the effect of adding fibre on the mechanical performance, microstructural characteristics, and thermochemical degradation behaviour of the mortars under conditions representative of high-temperature exposure during fires in energy infrastructure facilities. The scope of the research comprises establishing the modulus of elasticity using dog-bone-shaped specimens, as well as flexural and compressive strength tests performed on prisms measuring 4 × 4 × 16 cm and on 10 × 10 × 10 cm cubes to determine the strength class of the mortars. Microstructural analyses complemented the mechanical testing, performed with the use of scanning electron microscopy (SEM); this made it possible to assess temperature-induced changes in the cement matrix. The results have demonstrated that polypropylene fibres had a significant influence on the degradation behaviour of mortars subjected to elevated temperatures, particularly those between 200 and 400 °C, where fibre melting promoted the formation of additional pore channels. This phenomenon promotes the dissipation of internal energy associated with boiling water vapour contained in the capillary pores, as well as water released during the dehydration of cement hydration products, thereby limiting rapid pressure build-up and reducing the risk of explosive spalling. Moreover, the observed microstructural changes were associated with progressive decomposition of C–S–H gels and other thermo-chemical processes occurring within the cement matrix. The results confirm that polypropylene fibres act as a passive mechanism for the dissipation of thermal and mechanical energy in cement mortars, which has a positive effect on their performance under high-temperature conditions. The study provides new experimental data of significance for the design of cement-based materials with enhanced resistance to thermal exposure in energy-sector facilities. Full article

Explosive detonation is a high-speed and high-energy chemical-physical transformation process that rapidly generates high-temperature and high-pressure gases as well as shock waves. These energies are released intensely in a short time, exhibiting extremely strong destructive power. When these high-temperature and high-pressure gases and shock waves act on the surface of combustibles, they can instantly peel off the hot core on the surface, disrupting the conditions necessary for sustaining the combustion reaction and thereby achieving a fire-extinguishing effect. However, to attain this application goal, it is essential to select explosive materials with both high energy density and low sensitivity. In this study, DFTB-MD (Density Functional Tight-Binding Molecular Dynamics) and DFT (Density Functional Theory) methods were employed to systematically investigate the thermal decomposition process of benzotrifuroxan (BTF)/1,3,5-trinitrobenzene (TNB) cocrystal nanoparticles under high-temperature conditions. Our simulations reveal, for the first time, that the thermal decomposition mechanism of BTF/TNB cocrystal nanoparticles is strongly size-dependent: the 1.8 nm particles exhibit earlier ring-opening of BTF due to the higher surface-to-volume ratio, while the 2.2 nm particles show superior structural stability and lower molecular diffusivity. Meanwhile, increasing temperature from 2100 K to 2400 K shifts the dominant initial decomposition pathway from C–NO₂ cleavage in TNB to ring rupture in BTF. These findings provide atomic-scale theoretical insights into the design and application of BTF/TNB cocrystal nanoparticles for explosion-based fire suppression. Full article

Reservoir stimulation is essential in enhanced geothermal systems and unconventional reservoirs where low permeability, inadequate fracture connectivity, or near-wellbore damage restricts commercial injection or production. This review evaluates hydraulic fracturing, thermal stimulation, plasma-pulse stimulation, and selected dynamic stimulation technologies. It compares their physical mechanisms, fracture-network development, reservoir applications, permeability enhancement, operational maturity, deployment challenges, and future perspectives. Hydraulic fracturing remains the most mature method for reservoir-scale fracture creation, fracture conductivity, and reservoir connectivity. In enhanced geothermal systems, however, performance depends on the heat-exchange area, distributed flow, thermal sweep, long-term energy recovery, and induced-seismicity control rather than permeability enhancement alone. Thermal stimulation is integral to geothermal reservoir development. Cold-fluid injection generates thermoelastic stress redistribution, enlarges the fracture aperture, activates natural fractures, promotes thermally assisted fracture propagation, and influences thermal breakthrough. Plasma-pulse stimulation, also termed pulsed-power plasma, electrohydraulic, or shock-wave stimulation, provides a low-water method for near-wellbore permeability enhancement, damage bypass, fracture reactivation, and restimulation. Its broader deployment remains constrained by the limited treatment radius, scale-up uncertainty, energy-transfer efficiency, tool durability, completion integrity, and insufficient field validation. Liquid CO₂ phase-transition, propellant, and explosive stimulation provide additional dynamic-loading options with distinct fracture responses, controllability, safety, and technology readiness. Stimulation technologies should therefore be selected according to the dominant reservoir limitation and evaluated using sustained injectivity or productivity, effective reservoir contact, distributed flow, delayed thermal breakthrough, treatment durability, wellbore integrity, and a controlled geomechanical response. Future progress requires hybrid stimulation, coupled thermal–hydraulic–mechanical–chemical (THMC) modeling, integrated monitoring, adaptive control, physics-informed artificial intelligence, digital twins, standardized field validation, and techno-economic and life-cycle assessments. Full article