Fire Control Research Articles

SMWE-GFPNNet: A high-precision and robust method for forest fire smoke detection

Smoke is an early manifestation of forest fire. Accurate identification of smoke from forest fires is crucial for the prevention and control of forest fires, which helps protect the ecological environment and the safety of people. The texture features of smoke are complex and prone to detection omissions. The forest environment is complex, and smoke-like objects in the forest often interfere with smoke recognition. The concentration of smoke at the edge is thin, which easily leads to edge omission. In response to these problems, we propose a high-precision edge focused forest fire smoke detection network. To begin, in response to the problem of detection omission, we present a Swin multidimensional window extractor (SMWE) that enhances information exchange between windows in both horizontal and vertical dimensions to extract global texture features from images with smoke. Then, the guillotine feature pyramid network (GFPN) is suggested, along with a new guillotine convolution method for reducing redundant feature information from a feature fusion perspective, thereby improving the anti-interference ability of the model. Finally, taking into account the thinness and irregularity of the smoke near the borders, a contour adaptive loss function is suggested to minimize the boundary blur caused by down-sampling the feature map in the network. The experimental and application results show that SMWE-GFPNNet accomplishes 80.92 % of the mAP, 90.01 % of the mAP50, and 83.38 % of the mAP75 on the Forest Fire Smoke Complex Background Detection Dataset. Excellent in anti-interference ability and accuracy.

Effect of width and slope of large cross-section tunnel on ceiling smoke temperature under natural ventilation

ABSTRACT When a fire occurs in a large cross-section tunnel with slope, the distribution characteristic of ceiling smoke temperature illustrates special laws under the effect of chimney effect, the thermal radiation feedback, and the air entrance limit from walls. A series of numerical simulations are conducted through FDS simulation software based on the actual size of highway tunnel. The influence of large cross-section tunnel width and slope on ceiling smoke temperature when fire occurs are discussed. The research results show that (1) as the tunnel slope increases from 5° to 20°, the distance between the maximum ceiling smoke temperature point and the fire source is 0.5 m, 1 m, 1.7 m, 2.4 m, respectively, and the distance between the ceiling impact point and the fire source is 1 m, 1.8 m, 2.3 m, 3 m, respectively. As the tunnel width increases from 10 m to 20 m, the distance between maximum ceiling smoke temperature point and fire source increases 0.9 m, 1.1 m, 1.3 m, 1.8 m, 2.5 m, and 2.6 m. (2) The prediction formula of maximum ceiling smoke temperature is modified, and a dimensionless relationship among the maximum ceiling smoke temperature and tunnel slope and tunnel width is established. (3) The formula of longitudinal ceiling smoke temperature distribution is modified, and the relationship among tunnel slope, tunnel width, tunnel height, and longitudinal ceiling smoke temperature distribution is established. The research conclusions can provide a theoretical basis for fire prevention design, smoke control and evacuation of this kind of large cross-section tunnel fire.

Adaptation of the Coniferous Forests to Natural Fire Disturbances in the Altai Mountains, Xinjiang, China

The Altai Mountains, located in the northwesternmost part of China, have a harsh climate and little human activity, making it an excellent location to study forest ecology undisturbed by human interference. The forest is frequently struck by lightning and experiences long-term natural fire disturbances, leading to the evolution of unique fire adaptation traits in the major conifer species. To explore the role of natural fire disturbances in the Altai Mountain forest ecosystem, we conducted a study on the fire adaptation traits of Larix sibirica, Pinus sibirica, Picea obovata, and Abies sibirica, and reconstructed the fire history of the forest area over the past 100 years. We investigated three representative forest areas with varying fire disturbance conditions and habitats in the Altai Mountains. Data on fire disturbance conditions, relative air humidity, and species composition were collected in these areas. Basal diameter to diameter at breast height, relative bark thickness, and under-crown heights were measured and counted for each of the four species, and litter, bark, and wood layers were sampled and analyzed for physicochemical properties (ash, fat, and higher heating value) for each of the four species in the plots examined. We conducted a count of the four conifer species in the forest for each fire adaptation index and analyzed the differences in fire adaptation traits among the species. Larix sibirica showed fire-tolerant traits, Pinus sibirica displayed fire-embracer traits, and Picea obovata and Abies sibirica exhibited fire-avoider traits. Through the analysis of stand composition and exposure to fire disturbance in the different forest areas, we were able to correlate the fire-adaptive strategies of the four conifers with stand characteristics under varying fire disturbances and habitats. The interaction between forests and fires, and their adaptation to each other, ultimately create the current ecosystems in the Altai Mountains.

Shortening fire return interval predisposes west-central Canadian boreal peatlands to more rapid vegetation growth and transition to forest cover.

Climate change in northern latitudes is increasing the vulnerability of peatlands and the riparian transition zones between peatlands and upland forests (referred to as ecotones) to greater frequency of wildland fires. We examined early post-fire vegetation regeneration following the 2011 Utikuma complex fire (central Alberta, Canada). This study examined 779 peatlands and adjacent ecotones, covering an area of ~182 km2 . Based on the known regional fire history, peatlands that burned in 2011 were stratified into either long return interval (LRI) fire regimes of >80 years (i.e., no recorded prior fire history) or short fire return interval (SRI) of 55 years (i.e., within the boundary of a documented severe fire in 1956). Data from six multitemporal airborne lidar surveys were used to quantify trajectories of vegetation change for 8 years prior to and 8 years following the 2011 fire. To date, no studies have quantified the impacts of post-fire regeneration following short versus long return interval fires across this broad range of peatlands with variable environmental and post-fire successional trajectories. We found that SRI peatlands demonstrated more rapid vascular and shrub growth rates, especially in peatland centers, than LRI peatlands. Bogs and fens burned in 1956, and with little vascular vegetation (classified as "open peatlands") prior to the 2011 fire, experienced the greatest changes. These peatlands tended to transition to vascular/shrub forms following the SRI fire, while open LRI peatlands were not significantly different from pre-fire conditions. The results of this study suggest the emergence of a positive feedback, where areas experiencing SRI fires in southern boreal peatlands are expected to transition to forested vegetation forms. Along fen edges and within bog centers, SRI fires are expected to reduce local peatland groundwater moisture-holding capacity and promote favorable conditions for increased fire frequency and severity in the future.

Fire risk assessment of Kashan's commercial and shopping centers using fire risk assessment method for engineering (FRAME)

AbstractCommercial buildings are considered as high‐risk units in fire due to the existence of expensive equipment and large presence of people with different ages. Therefore, the present study aimed to assess the fire risk of commercial and shopping centers in Kashan using the fire risk assessment method for engineering (FRAME). This cross‐sectional study was conducted using FRAME in 15 commercial and shopping centers in Kashan, Iran. The risk assessment data and FRAME checklist were collected by observation and interviews. Data analysis was conducted using Excel and Geographic Information System (GIS) software. The results of 46 checklists showed that the mean score of fire risk R for property was equal to 3.12, for people 3.81 and for activities 1.86. Also, the lowest risk for the property, people and activities belongs to Golestan Center with a score of 1.40, Valiasr with a score of 1.25 and Ataee with a score of 1.15, and the highest risk for the property, people and activities belongs to Mir Seyfi Center with a score of 5.80, Shafagh with a score of 9.96 and Sabz was 2.62, respectively. The present study showed the lack of proper ventilation system, lack of emergency exits, and lack of automatic fire alarm and extinguishing system were the factors affecting fire risk. Therefore, in order to prevent disasters and uncontrollable critical conditions, it is necessary to review the equipment of these buildings and to design and implement fire detection and alarm equipment and different ways of fire control in these centers.

EVALUASI KECUKUPAN BANGUNAN PADA AREA PERKANTORAN

Fire is one of the impacts of potential hazards that often occur in the work area. Every company needs to have an automatic fire prevention and control system that meets fire prevention and control requirements, one of which is the administration of the placement of the number of workers that does not exceed the existing standard limits/rules. This type of research is a case study research that uses quantitative methods using secondary data, the data needed is data on the number of workers and building area in each work area. The results of the study show that the actual number of workers in each work area when compared to the number of people according to the standard, it can be said that they have met the standards that should be except for the 2nd floor of the Foundry office building. Researchers suggest companies to make improvements to all work area buildings to has an emergency response system that meets the requirements of integrated fire prevention and control and does not violate national and international standards.

Forecast Zoning of Forest Fire Occurrence: A Case Study in Southern China

Forest fires in the southern region of China pose significant threats to ecological balance, human safety, and socio-economic stability. Forecast zoning the occurrence of these fires is crucial for timely and effective response measures. This study employs the random forest algorithm and geospatial analysis, including kernel density and standard deviation ellipse methods, to predict forest fire occurrences. Historical fire data analysis reveals noteworthy findings: (i) Decreasing Trend in Forest Fires: The annual forest fire count in the southern region exhibits a decreasing trend from 2001 to 2019, indicating a gradual reduction in fire incidence. Spatial autocorrelation in fire point distribution is notably observed. (ii) Excellent Performance of Prediction Model: The constructed forest fire prediction model demonstrates outstanding performance metrics, achieving high accuracy, precision, recall, F1-scores, and AUC on the testing dataset. (iii) Seasonal Variations in High-Risk Areas: The probability of high-risk areas for forest fires in the southern region shows seasonal variations across different months. Notably, March to May sees increased risk in Guangxi, Guangdong, Hunan, and Fujian. June to August concentrates risk in Hunan and Jiangxi. September to November and December to February have distinct risk zones. These findings offer detailed insights into the seasonal variations of fire risk, providing a scientific basis for the prevention and control of forest fires in the southern region of China.

Large Fires and Climatic Variability in Urban Europe, 1500–1800

Several hundred large urban fires occurred in Europe during the early modern period, but they did not take place randomly. This article charts their incidence and reveals a peak in the seventeenth century, coinciding with some of the coolest periods of the Little Ice Age. This apparent paradox can best be explained by climatic variability, since overall cooling was accompanied by numerous warm, dry anomalies. While the cause of fires was usually human activity, and small fires happened frequently, this paper shows that many of the largest conflagrations of the early modern period took place in years of such hot and/or dry climatic anomalies, and closer analysis of individual fires confirms that these meteorological conditions facilitated their spread. This strongly suggests that climatic variability associated with the Little Ice Age was a major determinant of the timing of large fires in Europe. Over the same broad period, climatic disasters linked to cooler and damper conditions contributed to social and political instability, and there is evidence that this in turn undermined fire prevention and control and thus further increased the likelihood of small fires becoming large ones.

Plant-plant interactions influence post-fire recovery depending on fire history and nurse growth form

BackgroundsPlant-plant interactions are among the most important factors affecting the natural recovery of vegetation. While the impacts of nurse plants on species composition and biodiversity are well documented, the effects of different nurse’s growth forms on all biodiversity components including taxonomic, functional, and phylogenetic diversity have been less studied and compared, especially for their effects on different times after fire disturbance. This research was focused on comparing the effects of a perennial grass (Elymus hispidens), a perennial herb (Phlomis cancellata), and a high shrub species (Lonicera nummulariifolia) on species composition and the biodiversity components, and how these impacts change across five sites with short-term (1 and 4 years sites), long-term (10 and 20 years sites) times since last fire and a control site where no fire was known in recorded history in semi-arid shrublands of Fereizi Chenaran located in Northeast of Iran. The changes of species composition and taxonomic, functional, and phylogenetic diversity were calculated with respect to the presence/absence of nurse’s growth forms, fire history, and their interactions.ResultsNurse shrubs affected species composition and all biodiversity components, whereas all indices were reduced when considering Elymus grass as nurse plant. On the other hand, the herb Phlomis enhanced species composition and taxonomic diversity, while it had a negative effect on functional and phylogenetic diversity. Such specific effects of nurse types were mostly observed under long timescales (i.e., 10- and 20-year sites). Interestingly, the relative importance of nurse types and time since the last fire largely explained the variation of species composition and biodiversity components, with larger effects of nurse types on all biodiversity components. However, we found a significant contribution of fire explaining variation of species composition and phylogenetic diversity.ConclusionsThese results indicated nurse plants can affect the post-fire recovery of vegetation by providing specific mechanisms controlling beneficiary relatedness depending on their growth forms and time scales since the last fire. Therefore, these findings suggest perennial plants in the form of nurse species as a useful factor to develop techniques of active restoration in burned ecosystems.

A Bayesian model for predicting monthly fire frequency in Kenya.

This study presents a comprehensive analysis of historical fire and climatic data to estimate the monthly frequency of vegetation fires in Kenya. This work introduces a statistical model that captures the behavior of fire count data, incorporating temporal explanatory factors and emphasizing the predictive significance of maximum temperature and rainfall. By employing Bayesian approaches, the paper integrates literature information, simulation studies, and real-world data to enhance model performance and generate more precise prediction intervals that encompass actual fire counts. To forecast monthly fire occurrences aggregated from the Moderate Resolution Imaging Spectroradiometer (MODIS) data in Kenya (2000-2018), the study utilizes maximum temperature and rainfall values derived from global GeoTiff (.tif) files sourced from the WorldClim database. The evaluation of the widely used Negative Binomial (NB) model and the proposed Bayesian Negative Binomial (BNB) model reveals the superiority of the latter in accounting for seasonal patterns and long-term trends. The simulation results demonstrate that the BNB model outperforms the NB model in terms of Root Mean Square Error (RMSE), and Mean Absolute Scaled Error (MASE) on both training and testing datasets. Furthermore, when applied to real data, the Bayesian Negative Binomial model exhibits better performance on the test dataset, showcasing lower RMSE (163.22 vs. 166.67), lower MASE (1.12 vs. 1.15), and reduced bias (-2.52% vs. -2.62%) compared to the NB model. The Bayesian model also offers prediction intervals that closely align with actual predictions, indicating its flexibility in forecasting the frequency of monthly fires. These findings underscore the importance of leveraging past data to forecast the future behavior of the fire regime, thus providing valuable insights for fire control strategies in Kenya. By integrating climatic factors and employing Bayesian modeling techniques, the study contributes to the understanding and prediction of vegetation fires, ultimately supporting proactive measures in mitigating their impact.

Dendrochronological studies in North Africa: reality and prospects

The southern Mediterranean region, particularly North Africa, is a crucial area for biodiversity conservation. However, the impacts of climate change on plant species in this region are not well understood. Dendroecology, the study of tree rings, is a valuable technique for analyzing the effects of environmental changes on woody plants over time. In this study, we intend to assess the state of the art in dendrochronological research in North Africa and identify knowledge gaps and limitations in the field. The period of analysis spans from 1979 to 2023. We used all the available literature in Dendrobox and Google Scholar during this period. Our study revealed several research gaps in the region, including the need for more studies on the history of forest fires and their relationship to climate conditions in Morocco, Algeria, and Tunisia, the impact of climate on the anatomical characteristics of growth rings, and the effects of climate change on tree species diversity and forest health. Applying this technique in the future would allow for detailed insights into the effect of climate on the internal structure and growth of forest trees. The findings of this study will help guide future research and contribute to a better understanding of the climate-growth relationship of woody plants in North Africa.

Spatial and temporal patterns of forest fires in the Central Monte: relationships with regional climate

BackgroundNatural and anthropogenic wildfires burn large areas of arid and semi-arid forests with significant socio-economic and environmental impacts. Fire regimes are controlled by climate, vegetation type, and anthropogenic factors such as ignition sources and human-induced disturbances. Projections of climate and land-use change suggest that these controlling factors will change, altering fire regimes in the near future. In the southern Central Monte, Mendoza, Argentina, the factors that modulate the fire temporal and spatial variability are poorly understood. We reconstructed the fire history of southeast of Mendoza from 1984 to 2023 and investigated the relationships between fire extent and climate variability at seasonal and interannual scales. Burned areas were determined using Google Earth Engine by processing Landsat 5-TM, Landsat 7-ETM+ , and Landsat 8-OLI-TIRS sensor imagery.ResultsThe region exhibited high spatial and temporal variability in fire occurrence, being a mosaic of areas with different fire histories and recovery times. Between 1985 and 2023, fire recurrence ranged from sites unburned to sites with up to 14 fires. The occurrence of large fires was strongly favored by a combination of a year with abundant spring–early summer precipitation, which favors fuel accumulation, followed by a year of low spring–early summer precipitation. Precipitation and burnt area showed a very pronounced 6–7 year cycle, suggesting a dominant climatic control on fire occurrence.ConclusionsFire distribution in southeastern Mendoza forests is not homogeneous, resulting in a mosaic of patches with different fire histories. This heterogeneity may be related to vegetation patterns and land use. The temporal variability of fires is strongly influenced by climate variability, which would promote fuel production and subsequent drying. Large fires are concentrated in periods of high interannual precipitation variability. Climate change scenarios predict an increase in temperature and precipitation variability in the region, suggesting future changes in fire dynamics. Our results contribute to the development of fire guidelines for southeastern Mendoza forests, focusing on periods of wet years followed by dry years that favor fire occurrence and spread.

Use of immuno-flow cytometry and real-time PCR disclose the epidemiological behaviour of Erwinia amylovora populations during the winter in Portuguese pear orchards

AbstractThe persistence and progression of Erwinia amylovora in naturally infected orchards is still not fully understood and the majority of studies have been carried out under controlled or artificial infections. A major hurdle stems from the inability to characterize the viability of the bacterium in its natural state. Most standard tests, including real-time qPCR, fail to differentiate live from dead cells, while culture dependent methods lack sensitivity. Even in orchards with recurring infections, the detection of E. amylovora is erratic. Immuno-flow cytometry (IFCM) is considered a high throughput tool in clinics and food industry but has been rarely used as diagnostic test for plant pathogens. Two pear orchards with fire blight history, located in the central part of Portugal, were selected for epidemiological monitoring between February and June, from 2019 to 2022. A total of 440 samples were tested using EPPO standard diagnostic protocols. To address the epidemiological behaviour of E. amylovora, we devised an IFCM test using specific monoclonal antibodies and viability dyes, validated in a subset of 149 samples, testing positive in routine diagnostic tests. Our IFCM test was able to differentiate live and dead E. amylovora in naturally infected samples with concentrations as low as 3.54 × 104 cell·mL−1, confirming positive results for 91% these samples, while 19.4% were considered positive by isolation, 38% using conventional PCR and 95% for real-time qPCR. Temporal analysis showed the highest number of positive samples regardless of the method employed in April, May and June, while viability values measured with IFCM were the highest in April, coinciding with the exit of dormancy and early flowering of pear trees. Integrative analysis of E. amylovora viability and population dynamics over the growing season allowed identification of distinct outbreak risks associated with these Portuguese pear orchards.

Forest fires in the Indian Central Himalaya: major drivers, implications, and mitigation measures

ABSTRACT Forest fires pose a significant threat in the Central Himalaya due to both natural and human factors. This study investigates key drivers, consequences, and mitigation measures. Data on 2022 forest fire incidents, affected areas, and economic losses were collected from the State Forest Department, Dehradun, and analyzed using statistical methods. The 2022 forest fire areas were mapped using data from the USGS and NASA FIRMS portals, revealing highly sensitive zones in river valleys and mid-altitudes below 1800 m, covering 13% of the total forest area (approximately 40,000 ha). These regions primarily host monsoon deciduous and flammable pine forests. Recent years have witnessed a notable increase in fire frequency and intensity, attributed to warming river valleys, middle altitudes, and dry climate spells during the fire season. This pioneering study recommends risk reduction strategies, including managing dry pine leaves, forest replacement, constructing fire lines, and providing fire control training to rural communities. Adopting these measures can effectively mitigate the escalating threat of forest fires in the Central Himalaya.

Pyrogeography of the Western Great Plains: A 40-Year History of Fire in Semi-Arid Rangelands

This study describes spatial and temporal patterns in fire across the US Western Great Plains over the last 40 years. Although pyrogeographic studies have explored the nexus of fire patterns in relation to the bio-physical environment and socio-ecological trends, most of this research has focused on forested ecosystems and regions long known for conflict between wildfires and human development, especially at the wildland–urban interface. But evidence suggests large wildfire activity is increasing in the US Great Plains, and the Western Great Plains—a Land Resource Region comprised of four ecoregions, Northwestern Plains, High Plains, Nebraska Sandhills, and Southwestern Tablelands—not only contains some of the largest areas of rangeland in the US but also the highest concentration of public land in the Great Plains. As such, the Western Great Plains provides an opportunity to explore fire activity in primarily rural landscapes with a combination of public and private ownership, all dominated by rangeland vegetation. We combined several publicly-available datasets containing fire records between 1992 and 2020 to create two databases, one with georeferenced point data on 60,575 wildfire events in the region, and another with georeferenced perimeter data for 2665 fires. Ignition by humans was the dominant cause of fires. No ecoregion showed a statistically significant trend towards either increasing or decreasing the annual burned area. The Northwestern Plains had the most burned area and the greatest number of incidents—consistently around or above 1000 incidents per year since 1992—with the majority in July. The High Plains showed the greatest increase in annual fire incidence, never reaching more than 200–300 per year 1992–2009, and averaging above 1000 incidents per year since 2010. Few long-term trends in human population, weather, or fuel metrics appear strongly associated with fire patterns in any ecoregion, although the years 2006, 2012, and 2017 stood out for their levels of fire activity, and these years often frequently logged extreme values in wildland fuel metrics. These relationships merit much closer examination in the Western Great Plains, because like other rangeland-dominated landscapes, the fine fuels that comprise these wildland fuelbeds are much more responsive to fine-scale changes in moisture conditions. Rural Western Great Plains landscapes are a mosaic of public and private land ownership, and an increasing impact of wildfires on public grazing lands—which are often situated within other jurisdictions or ownership—will likely have an impact on rural livelihoods.

Human influence on late Holocene fire history in a mixed-conifer forest, Sierra National Forest, California

BackgroundUnderstanding pre-1850s fire history and its effect on forest structure can provide insights useful for fire managers in developing plans to moderate fire hazards in the face of forecasted climate change. While climate clearly plays a substantial role in California wildfires, traditional use of fire by Indigenous people also affected fire history and forest structure in the Sierra Nevada. Disentangling the effects of human versus climatically-induced fire on Sierran forests from paleoecological records has historically proved challenging, but here we use pollen-based forest structure reconstructions and comparative paleoclimatic-vegetation response modeling to identify periods of human impact over the last 1300 years at Markwood Meadow, Sierra National Forest.ResultsWe find strong evidence for anthropogenic fires at Markwood Meadow ca. 1550 – 1750 C.E., contemporaneous with archaeological evidence for fundamental shifts in Indigenous lifeways. When we compare our findings to five other paleoecological sites in the central and southern Sierra Nevada, we find evidence for contemporaneous anthropogenic effects on forest structure across a broad swath of cismontane central California. This is significant because it implies that late 19th and early twentieth century forest structure – the structure that land managers most often seek to emulate – was in part the result anthropogenic fire and precolonial resource management.ConclusionWe consequently suggest that modern management strategies consider (1) further incorporating traditional ecological knowledge fire practices in consultation with local tribal groups, and (2) using pollen-based reconstructions to track how forest composition compares to pre-1850 C.E. conditions rather than the novel forest states encountered in the late 20th and early twenty-first centuries. These strategies could help mitigate the effects of forecast climate change and associated megafires on forests and on socio-ecological systems in a more comprehensive manner.

Sipongi System: Navigating and fostering collaboration in Indonesia

The Sipongi System is essential in dealing with forest and land fires because this system provides real-time data that empowers stakeholders and communities to proactively overcome fire dangers. Its advantages are seen in its ability to provide detailed information regarding weather conditions, wind patterns, water levels in peatlands, air quality, and responsible work units. This data facilitates efficient decision-making and resource allocation for fire prevention and control. As an embodiment of Collaborative Governance, the Sipongi System actively involves various stakeholders, including government institutions, local communities, environmental organizations and the private sector. This cooperative approach fosters collective responsibility and accountability, improving fire management efforts. The Sipongi approach is critical in reducing forest and land fires in Indonesia by providing real-time data and a collaborative governance model. This results in faster response times, more effective fire prevention and better resource allocation. Although initially designed for Indonesia, the adaptable nature of the system makes it a blueprint for addressing similar challenges in other countries and regions, tailored to specific needs and environmental conditions. Qualitative research methods underlie this study, including interviews with key stakeholders and analysis of credible sources. Government officials, community leaders, environmental experts and organizational representatives were interviewed to comprehensively examine the mechanisms of the Sipongi System and its impact on forest and land fire management in Indonesia. Future research should explore the application of Sipongi Systems and collaborative governance in various contexts by conducting comparative studies across countries and ecosystems. Additionally, assessing the long-term impact and sustainability of the Sipongi System is critical to evaluating its effectiveness over time.

Numerical Evaluation of Sodium Droplet Swarm Combustion and Its Modeling Optimization

Because of its superior thermal-hydraulic qualities, liquid sodium has been applied to a variety of industries, including energy storage, solar energy, sodium-cooled fast reactors, and aerospace. However, fires brought on by sodium leaks at high pressure can have major thermodynamic repercussions and put employees and equipment in use at risk directly or indirectly. As a result, a realistic and accurate forecast of the combustion behavior of sodium droplet swarm can offer technical backing for the use of liquid sodium in engineering as well as a way of sodium fire prevention and control. Spray dynamics (droplet settling, droplet particle size distribution, etc.), combustion kinetics (premixed combustion, gas phase combustion, etc.), sodium aerosol diffusion, and other specialized phenomena all contribute to the complex process of sodium droplet swarm combustion. The NACOM code created by Brookhaven National Laboratory for sodium droplet swarm combustion is utilized in this paper as a framework. The code is first validated using the benchmark of the sodium droplet swarm combustion tests carried out by prestigious institutions. The validation results demonstrate that the code’s drag model, droplet combustion model, and heat transfer model are to blame for the significantly overestimated thermodynamic effects of sodium droplet swarm combustion. NACOM is subsequently developed twice for the authors’ previously developed vapor-liquid two-layer-structure drag model, chemical kinetic combustion model, and suitable heat transfer coefficient. It is then thoroughly assessed for the separate-effects tests and integral-effects test. The evaluation results demonstrate that the optimized drag model accelerates the settling of sodium droplets due to the consideration of the sodium-vapor drag reduction effect, reducing the thermodynamic effects of liquid sodium combustion; the optimized premixed combustion model can accurately predict the low-temperature sodium droplet swarm combustion conditions, resolving the issue of serious misvaluation of the original version of NACOM. The associated research findings can serve as valuable resources and tools for deeper comprehension of the combustion effects and mechanisms of sodium droplet swarm under various operating settings (such as leakage rate and oxygen concentration).

Single versus multiple firesetting: an examination of demographic, behavioural and psychological factors

Deliberate firesetting is a prevalent issue. While a number of psychological treatment needs have been identified for adults who set fires, their association with multiple firesetting has received limited attention. This study examined whether demographics, offence histories, firesetting behaviours and psychometric assessments of psychological vulnerabilities hypothesised to be associated with firesetting discriminate between adults who have set only one fire and those who have set multiple fires. Participants (N =128) were recruited from prisons and categorised according to whether they self-reported having set only a single fire (n = 60) or multiple fires (n = 68) as an adult. Our findings provide evidence that identification with fire, antisocial attitudes and anger-related cognition and arousal are associated with multiple firesetting, and therefore represent key treatment targets for interventions. Furthermore, a history of setting fires within prison was the largest unique predictor of multiple firesetting (odds ratio, OR = 6.83), highlighting the urgent need for research on institutional firesetting.

Long-term efficacy of fuel reduction and restoration treatments in Northern Rockies dry forests.

Fuel and restoration treatments seeking to mitigate the likelihood of uncharacteristic high-severity wildfires in forests with historically frequent, low-severity fire regimes are increasingly common, but long-term treatment effects on fuels, aboveground carbon, plant community structure, ecosystem resilience, and other ecosystem attributes are understudied. We present 20-year responses to thinning and prescribed burning treatments commonly used in dry, low-elevation forests of the western United States from a long-term study site in the Northern Rockies that is part of the National Fire and Fire Surrogate Study. We provide a comprehensive synthesis of short-term (<4 years) and mid-term (<14 years) results from previous findings. We then place these results in the context of a mountain pine beetle (MPB; Dendroctonus ponderosae) outbreak that impacted the site 5-10 years post-treatment and describe 20-year responses to assess the longevity of restoration and fuel reduction treatments in light of the MPB outbreak. Thinning treatments had persistently lower forest density and higher tree growth, but effects were more pronounced when thinning was combined with prescribed fire. The thinning+prescribed fire treatment had the additional benefit of maintaining the highest proportion of ponderosa pine (Pinus ponderosa) for overstory and regeneration. No differences in understory native plant cover and richness or exotic species cover remained after 20 years, but exotic species richness, while low relative to native species, was still higher in the thinning+prescribed fire treatment than the control. Aboveground live carbon stocks in thinning treatments recovered to near control and prescribed fire treatment levels by 20 years. The prescribed fire treatment and control had higher fuel loads than thinning treatments due to interactions with the MPB outbreak. The MPB-induced changes to forest structure and fuels increased the fire hazard 20 years post-treatment in the control and prescribed fire treatment. Should a wildfire occur now, the thinning+prescribed fire treatment would likely have the lowest intensity fire and highest tree survival and stable carbon stocks. Our findings show broad support that thinning and prescribed fire increase ponderosa pine forest resilience to both wildfire and bark beetles for up to 20 years, but efficacy is waning and additional fuel treatments are needed to maintain resilience.