Search Results (537)

This study presents a fire risk prediction framework applied to two conservation units within the Atlantic Forest biome (AFb): Serra da Gandarela National Park (PNSG), Minas Gerais, and Campos de Palmas Wildlife Refuge (RVSCP), Paraná. Daily climate data (2001–2023), remote sensing vegetation indices Normalized Difference Vegetation Index (NDVI) and Normalized Multi Band Drought Index (NMDI), fire foci, and estimates of soil volumetric moisture were integrated to analyze the climatic and environmental drivers of fire occurrence and to develop predictive models. Sea Surface Temperature (SST) anomalies in the Niño 3.4 region revealed the influence of El Niño–Southern Oscillation (ENSO) variability on local hydrometeorological dynamics. Vegetation indices and soil moisture data reinforced this relationship, with NMDI values below 0.4 and sharp declines in volumetric moisture indicating water stress during the dry season. Kernel density maps identified clusters of fire foci during this period, confirming the strong seasonality of fire occurrence. Based on climatic predictors and environmental indicators, fire risk indices were developed for each conservation unit and validated using independent data. Model performance showed moderate explanatory capacity, with coefficients of determination ranging from 0.53 to 0.68 and high agreement between estimated and observed values. Validation stratified by ENSO phases (Neutral, El Niño, and La Niña) demonstrated stable performance across contrasting climatic regimes, indicating temporal resilience of the modeling framework. Overall, the integration of climate data, spectral indices, and soil moisture information improves the ability to anticipate fire risk in Atlantic Forest conservation units, providing a useful tool to support prevention, monitoring, and decision-making in protected areas. Full article

SiO₂ aerogel cement composites (SACCs) are promising for building insulation, but how their residual thermal performance evolves after high-temperature exposure remains unclear, limiting fire protection assessment. In this study, SACC specimen with aerogel contents of 0%, 5%, 7%, and 10% were heat-treated at 400, 600, 700, 800, and 1000 °C. After cooling, their post-exposure thermal performance and microstructure were characterized via mass loss, density, thermal conductivity, MIP, and SEM. Results obtained at room temperature showed that with increasing treatment temperature, thermal conductivity first decreases and then increases, reaching a minimum after 700 °C treatment for the A7 specimens (from 0.092 to 0.063 W/(m·K)). Microstructural analysis of cooled specimens revealed that this non-monotonic behavior arises from three heat-induced changes: the cement matrix, aerogel aggregates, and the interfacial gap between them. After treatment at 700 °C, the gap corresponds to a Knudsen number of 0.01–0.02, entering the slip-flow regime. Combined with the low thermal conductivity of the cement matrix, this yields the best insulation. After treatment at 800 °C and above, the gap exceeded 60 μm, shifting heat transfer to the continuum regime and reducing insulation capacity. A thermal conductivity prediction model based on these post-exposure mechanisms agreed well with the experimental results. Full article

Wildfires are among the key drivers of transformation in boreal ecosystems; however, the mechanisms of postfire recovery in the arid regions of Eurasia remain insufficiently understood. The aim of this study was to identify the role of burn severity and associated edaphic and hydrological factors in shaping the natural regeneration trajectories of Scots pine forests in the Kostanay region of northern Kazakhstan. This study is based on the integration of field data on seedling regeneration and soil conditions with the analysis of long-term satellite-derived indices (NDVI, NDMI, and NBR). Sample plots were grouped according to fixed burn severity classes, which enabled a consistent statistical comparison and reduced the interpretative ambiguity that has characterized previous studies in the region. The results indicate that pine forest regeneration is most successful under low and moderate burn severity, where seed sources are preserved and favourable moisture conditions are maintained. In contrast, high burn severity leads to a reduction in regenerative potential and a shift in recovery trajectories toward deciduous or sparsely vegetated communities. The spectral indices derived from the remote sensing data strongly agreed with the field-based indicators, confirming their suitability for assessing postfire vegetation dynamics. Soil properties act as important modifying factors of recovery processes, particularly under conditions of limited water availability. These findings enhance the current understanding of postfire recovery mechanisms in the arid part of the boreal zone and highlight the need for differentiated management of postfire landscapes. The integration of field observations with remote sensing data provides a robust framework for monitoring and forecasting recovery processes under an increasingly intensified fire regime. Full article

Wildfire monitoring systems increasingly rely on satellite-derived risk surfaces to support resource-constrained prioritization. However, less attention has been paid to how spatial aggregation interacts with alarm sparsity in shaping event-level wildfire capture. This study conducts a retrospective evaluation of percentile-based wildfire alarm regimes in California during the 2024 fire season. Using VIIRS-derived risk surfaces and MTBS burned-area perimeters, the analysis examines three aggregation scales (375, 1000, and 5000 m) under fixed alarm budgets (top 1%, top 5%, and top 10%). Event-level capture was evaluated by aggregating row-level capture values within each MTBS event, with the primary specification based on maximum event-level capture and a threshold of 0.02. Across 2078 unique wildfire events, the effect of spatial aggregation was conditional on alarm sparsity. Under the most restrictive budget (top 1%), scale effects were weak and non-monotonic. In contrast, under the top 5% and top 10%, the coarsest scale (5000 m) consistently produced the highest event-level threshold-exceedance rates. Robustness checks using mean event-level capture and a stricter threshold of 0.05 yielded qualitatively similar patterns under moderate alarm budgets. These findings indicate that the effect of spatial aggregation cannot be interpreted independently of alarm-budget design. Rather than treating spatial resolution as inherently beneficial or detrimental, the study shows that its implications depend on how event-level capture is evaluated under constrained alarm allocation. Full article

Lodgepole pine (Pinus contorta Dougl.) exhibits pronounced morphological variation across its range, historically attributed to allopatric differentiation during the Wisconsin glaciation. However, whether genetic divergence aligns with morphological differentiation—a fundamental prediction of allopatric speciation theory—remains untested. We conducted a comprehensive phylogeographic analysis of chloroplast DNA (trnL intron and trnL/trnF spacer) and mitochondrial DNA (nad1 b/c intron) across 31 populations representing all four recognized subspecies to test hypotheses of refugial isolation and to evaluate the genetic basis of current taxonomic classification. Contrary to predictions of allopatric divergence, both organellar genomes showed striking genetic uniformity (π = 0.000178–0.000186; intersubspecific genetic distances: 1.06 × 10⁻⁴ to 3.96 × 10⁻⁴) with no phylogenetic structure corresponding to morphological boundaries. Significant negative neutrality test values (Tajima’s D = −2.26, p < 0.02; Fu and Li’s D* = −4.52, p < 0.02) suggest recent demographic expansion rather than equilibrium divergence. A distinctive 5 bp indel in coastal populations provides molecular evidence for a northern Pacific refugium, and its occurrence in interior populations is consistent with post-glacial pollen-mediated gene flow, though this directionality remains inferential pending nuclear genomic confirmation. These findings suggest that morphological divergence reflects rapid adaptive evolution in heterogeneous environments rather than deep phylogenetic divisions. This pattern exemplifies gene flow-selection balance, in which divergent selection maintains local adaptation despite extensive gene flow—supporting an ecotypic rather than a phylogenetic interpretation of intraspecific diversity. The persistence of morphological variation despite genetic homogeneity indicates strong selection on ecologically important traits, likely driven by variation in fire regimes, differential seed predation, and climate gradients. These results have critical implications for understanding adaptive evolution rates in widespread conifers and for developing conservation strategies that emphasize adaptive processes over taxonomic categories. Full article

Annual area burned correlates with temperature and fuel aridity, yet extreme wildfire outcomes arise from a small fraction of fires and rapid-growth days. This asymmetry indicates that thermodynamic favorability sets background susceptibility but does not determine when extreme growth occurs. This Perspective proposes a cross-scale framework that distinguishes susceptibility from regime-conditioned event-scale realization. At seasonal and regional scales, temperature and humidity influence fuel dryness, ignition likelihood, and fire-season length, explaining substantial interannual variability in area burned. These variables vary smoothly in space and retain signal under aggregation. By contrast, extreme fire growth occurs during short-lived synoptic configurations that organize winds, pressure gradients, and stability into discrete opportunity windows that permit sustained spread. The strongest winds governing rapid spread are intermittent, terrain-structured, and often unresolved in coarse datasets or aggregated indices. Within these windows, terrain interactions, organized flow, and fire–atmosphere feedbacks can amplify growth until circulation patterns shift. Extreme wildfire behavior therefore operates as a gated joint-probability process requiring the coincidence of susceptibility (S), dynamical weather opportunity (W), and ignition (I). Separating susceptibility from realization reconciles strong climate–fire correlations with the dynamical control of event-scale extremes. Full article

This article compares selected fire safety regulatory systems in Japan, China, the United States, and the EU/UK, interpreted through the lens of responsive architecture and the implementation of digital technologies—building information modelling (BIM), digital twins (DTs), artificial intelligence (AI), and the Internet of Things (IoT). The study adopts a qualitative approach based on a structured review of legal acts, technical standards, public-sector reports, and the scientific and professional literature, organised using a common analytical framework. First, the analysis identifies shared foundations across regimes: the primacy of life safety, mandatory detection and alarm functions, fire compartmentation, requirements for protected means of exit, and the increasing importance of documenting the operational status of protection measures. Then, it contrasts key differences, including the permissibility of performance-based design (PBD), the degree to which digital documentation is formally recognised, organisational enforcement models, and cybersecurity approaches for integrated fire alarm/voice alarm/building management/IoT ecosystems. Japan and selected Chinese cities combine stringent requirements with openness to dynamic solutions and urban-scale data platforms. The USA relies on a decentralised code-based ecosystem with a strong role for professional and industry bodies, while the EU/UK continues to strengthen harmonised standards and digital building registers, reinforced by lessons after the Grenfell Tower fire. Against this background, Poland is discussed as broadly aligned in goals and baseline technical requirements yet lagging behind in implementing PBD pathways, digital registers, formal BIM/DT integration, and minimum cybersecurity requirements. The proposed directions for change aim to create a more predictable regulatory and technical framework for the development of responsive architecture and dynamic fire safety systems in Poland. The study contributes to the sustainability literature by framing regulatory readiness for digital fire safety as a lifecycle resilience strategy, directly relevant to safe, resource-efficient, and inclusive built environments. Full article

The convergence of sensing and processing is a critical frontier in the development of energy-efficient spiking edge intelligence. This paper presents a novel hardware implementation of a sensory neuron evolving from the leaky integrate-and-fire (LIF) model by coupling a volatile memristor with an LC tank circuit. The proposed memristor–resistor–inductor–capacitor (MRLC) neuron embeds electromagnetic sensing directly into neuronal dynamics, enabling direct transduction of proximity information into spike trains. We demonstrate that the circuit functions as a metal-sensitive proximity sensor with spiking output in both simulation and physical experiments. Moreover, the MRLC neuron exhibits rich dynamical regimes, including regular spiking, bursting with 2–5 spikes per burst, and quasi-chaotic behavior, as well as sensing memory provided by hysteresis-like multistability, which is a notable advancement over simple rate-encoding LIF neurons. Full article

Wildfires are a major natural hazard causing extensive ecological damage and endangering human survival. Previous studies on wildfires in China have mostly focused on specific regions or individual drivers, with limited systematic assessments at the long-term and national scales. The spatiotemporal patterns of wildfires and their multiple driving mechanisms under China’s diverse climatic regimes remain insufficiently understood. To bridge this gap, we combined MCD64A1 burned area data (2001–2023) with multi-source natural (meteorological, vegetation, and topographic) and anthropogenic factors, using random forest models at both the national and regional scales to examine the spatiotemporal patterns, dominant drivers, and response mechanisms of wildfires in China. The results revealed that: (1) Spatially, wildfires were concentrated in northeastern and southern China, which accounted for 86.20% of the total burned area. Temporally, northern wildfires were primarily a spring-dominated fire regime, with peak activity in March and April, whereas southern wildfires were winter-dominated, peaking in February. (2) At the national scale, elevation was the key topographic factor influencing wildfire occurrence (relative importance = 0.49), with low-elevation and gentle-slope areas being more fire-prone. At the regional scale, the driving factors exhibit spatial differentiation, forming a spatial pattern of topography-dominated and climate-dominated. (3) Partial dependence plot analysis revealed nonlinear and threshold responses. Fire probability increases rapidly when the soil moisture is below 20 mm, while extremely high land surface temperatures in arid regions suppress fire occurrence due to fuel limitations. This study enhances the understanding of spatially heterogeneous wildfire drivers in China and provides a scientific basis for region-specific wildfire prevention and management strategies. Full article

We revisit a hyperbolic wildfire model based on reaction–diffusion dynamics with relaxation effects and extend it by incorporating an advection transport term that accounts for wind-driven fire spread. After a planar two-dimensional reformulation and non-dimensionalization of the model, the analysis is restricted to the minimal ignition regime characterized by the presence of a logistic reaction term governing the evolution of the fire-affected tree fraction. The focus of the study is to assess the influence of the effective wind velocity on the propagation dynamics of the fire-affected tree fraction. For this purpose, analytical solutions of the extended wildfire model are derived by applying the Simple Equations Method (SEsM) in its (1,1) variant using a Riccati-type ordinary differential equation as a simple equation. The obtained families of exact solutions describe physically relevant transition fronts connecting fire-unaffected and fully fire-affected states, or vice versa. Numerical simulations of the derived analytical solutions are performed to demonstrate how the internal front thickness and the profile morphology depend on the specific variant of the Riccati-type solution and on the magnitude of the effective wind velocity. A phase-plane stability and bifurcation analysis of the reduced traveling wave system is carried out. Hopf bifurcation thresholds with respect to the effective wind velocity parameter are identified, revealing transitions between monotone front propagation and oscillatory regimes. A regime map is constructed in the parameter plane spanned by the effective wind velocity and the traveling wave speed. This regime diagram delineates regions of qualitatively different propagation behavior, including monotone advancing fronts, possible oscillatory regimes, and regimes in which traveling wave fronts cease to exist. Full article

Community land management plays an important role in wildfire-prone landscapes in Mediterranean Europe. However, in Portugal, information on the spatial extent and boundaries of community land remains fragmented across multiple institutions. This study addresses a critical but often overlooked issue in wildfire management: the fragmentation of institutional data on community land boundaries in mainland Portugal and its direct implications for forest fire risk management, planning, and accountability. We harmonized georeferenced datasets from various government and public institutions, applying multi-institutional spatial integration supported by legal land use criteria using the Land Use Land Cover map 2018 (LULC2018). The resulting national map represents the first fully harmonized spatial assessment of community land (baldios) in mainland Portugal. Our results show that baldios currently occupy approximately 595 thousand hectares, significantly exceeding official estimates. Of this total, around 74% are under partial forest regime law, and approximately 76% are classified as having a high or very high wildfire hazard. This means that three out of every four hectares of baldios in mainland Portugal are structurally susceptible to extreme wildfire conditions. Beyond improving cartographic data, the study’s findings demonstrate how the lack of land registry weakens the institutional foundations for community-based wildfire management. Without a functional, legally validated national map of community land boundaries, responsibilities, co-management mechanisms, and prevention measures remain spatially inconsistent. Full article

This study evaluates the costs and benefits of participatory forest management (PFM) versus non-participatory forest management based on the perceptions and involvement of local communities in the Kilombero Valley Ramsar site, Tanzania. The area hosts ecologically significant wetlands managed through different regimes: forests managed by local communities under PFM and protected areas controlled by national authorities. Using data collected through focus groups, key interviews, household surveys, and direct observations in two villages—Siginali (PFM) and Kilama (non-participatory)—this research explores perceptions of two different forest management approaches. The results revealed: (i) a generally low awareness and participation in forest management activities in both villages; (ii) restrictions on forest resource access, essential for local livelihoods, were common and often poorly accepted in the two villages; (iii) neither approach alleviates poverty, instead, strict regulations have worsened livelihoods by eliminating traditional income sources; (iv) forced participation in patrols and fire control was also noted as an unfair burden without direct compensation; and (v) the “fortress” model is perceived as more effective at improving forest health and stopping illegal activity due to stricter patrols. The study concludes that while PFM supports forest sustainability, it needs enhanced local engagement, benefit-sharing mechanisms, and complementary income-generating initiatives such as ecotourism to sustainably balance conservation and community welfare. Full article

The integration of hydrogen into natural-gas-fired gas turbines represents a promising transitional pathway for reducing greenhouse gas emissions in industrial power generation. This study presents a comparative thermodynamic and environmental assessment of a Solar Titan 130 gas turbine operating in combined heat and power (CHP) mode under two fueling conditions: conventional natural gas and a hydrogen-enriched CH₄/H₂ (80/20 vol.%) blend. The analysis combines validated operational data for natural gas with analytical thermodynamic modeling for the blended-fuel scenario to evaluate key performance indicators, including thermal efficiency, specific fuel consumption, power output, and carbon dioxide emissions. The results indicate that hydrogen enrichment leads to an increase in thermal efficiency from 34.1% to 36.6% and a reduction in specific CO₂ emissions by approximately 13.7%, while maintaining similar thermal input within the adopted steady-state modeling framework. Compressor power consumption decreases, and net electrical output increases slightly under hydrogen-enriched operation, contributing to improved overall energy performance. Although the hydrogen-blended regime is assessed through modeling, the findings suggest that moderate hydrogen addition can enhance efficiency and environmental performance in industrial gas turbines without fundamental structural redesign of the turbine core, assuming appropriate fuel supply and control system adaptation. The study provides practical insights into the feasibility of hydrogen-assisted operation in existing CHP installations and supports its role in near-term decarbonization strategies. Full article

Reducing friction in the piston ring–cylinder liner contact is a key area for improving the efficiency of internal combustion engines. While tribological studies commonly focus on the top dead centre region using linear tribometers, the mid-stroke regime—with its higher sliding velocities—remains experimentally inaccessible to most conventional test methods. This study presents a rotating ring-on-liner tribometer that enables investigations at constant relative speed by transitioning the motion from oscillating to rotating. A cylindrical substitution geometry for the piston ring specimen is derived through a coupled elastohydrodynamic and asperity contact simulation approach to reproduce realistic load-sharing behaviour. Experimental results from starved lubrication tests demonstrate stable contact conditions with a low coefficient of variation in wear, confirming good reproducibility. Stepwise performed Stribeck tests at 40 °C and 100 °C reveal characteristic friction–velocity behaviour, including the transition from mixed to hydrodynamic lubrication. Although the test rig’s maximum sliding speed and steady-state thermal conditions differ from fired engine environments, the methodology closes an important gap between low-speed linear tribometers and complex floating-liner systems. The presented approach provides a flexible and robust platform for controlled parametric studies of ring-on-liner contacts under application-relevant lubrication regimes. Full article

Fire smoke, rich in toxic ultrafine particles and polycyclic aromatic hydrocarbons (PAHs), poses significant health risks to first responders and vulnerable populations. In this study, a reproducible combustion–smoke simulation platform was developed to mechanistically quantify fire behavior, particle emissions, and PAH toxicity under controlled heat flux and oxygen conditions. Consistent combustion and smoke emissions were achieved by measuring heat release rate, particle mass, particle number concentration, and PAH concentration, with an overall average coefficient of variation below 15%. Systematic experiments with representative biomass (pine, oak) and plastics (PVC, polystyrene) demonstrate that fuel composition, heat flux, and oxygen availability jointly govern particle formation and PAH partitioning. Regardless of the combustion factors, ultrafine particles dominated the particle number concentration (55.5–86.2%). Plastic combustion generated 7 to 59 times particle mass, up to 260 times higher PAH emissions, and up to 58,500 times greater PAH toxic equivalent quotient (PAH-TEQ) than wood. Oxygen-deficient and smoldering regimes shifted emissions toward fine and ultrafine particles enriched in high-molecular-weight PAHs, revealing a coupled physical–chemical hazard not captured by bulk PM metrics alone. These results establish a quantitative framework linking combustion regime, particle size, and PAH toxicity, providing critical insight for exposure assessment, PPE design, and mitigation strategies in ventilation-limited and mixed-fuel fire scenarios. Full article