Fire Range Research Articles

RESEARCH PECULIARIRIES OF WARHEAD FUSES FOR “KAMIKAZE” TYPE UAVs

To defeat surface targets "kamikaze" type UAVs with computer-integrated warheads are used. After preliminary target designation or finding it independently, “kamikaze” type UAV can destroy it, diving on the target as guided ammunition. Defeat characteristics of built-in warhead mainly depend on warhead itself and its fuse.
 The results of the combat mission of a UAV type "kamikaze" to hit typical targets are directly affected by the characteristics of the integrated warhead. The characteristics of destructive effect of the integrated warhead mainly depend on its type and explosive device.
 To simplify fuse„s characteristics proving process there is sense to divide them on groups, depending on method of their obtainment.
 To evaluate common parameters, concerning raw material use, components, proving of technical and economic requirements, correspondence to standardization and unification requirements, ergonomic and esthetic requirements is better to use existing standards and procedures for warhead and fuse evaluation. Laboratory tests prove mainly climatic and mechanical factors resistance. Proving of warhead and fuse effectiveness should be executed on fire range on final stage of "kamikaze" UAV test.
 Reliable evaluation results and characteristics are possible after investigation with special laboratory and fire range infrastructure.
 At present, the problematic issues of research of integrated warheads explosive devices are the determination of devices expiration service terms and their effectiveness when using UAVs of the "kamikaze" type under utmost permissible operation conditions etc.
 “Kamikaze” UAV warhead fuse directly influences on target damage level and should be developed and tested under exacting requirements. Therefore, reliable fuse characteristics, reached during investigation (including fire range test) define whole “kamikaze” UAV effectiveness of operational use.

Application of unmanned aerial vehicle (UAV) thermal infrared remote sensing to identify coal fires in the Huojitu coal mine in Shenmu city, China

China is a major coal-producing country that consumes large amounts of coal every year. Due to the existence of many small coal kilns using backward mining methods, numerous worked-out areas have been formed. The coal mines were abandoned with no mitigation, so air penetrates into the roadways and contacts the coal seams; as a result, the residual coal seams spontaneously ignite to form coal fires. These coal fires have burned millions of tons of valuable coal resources and caused serious environmental problems. To implement fire suppression more effectively, coal fire detection is a key technology. In this paper, thermal infrared remote sensing from unmanned aerial vehicle combined with a surface survey is used to identify the range of coal fires in the Huojitu coal mine in Shenmu city. The scopes and locations of the fire zones are preliminarily delineated, which provides an accurate basis for the development of fire suppression projects.

Cost-Effective Prescribed Burning Solutions Vary Between Landscapes in Eastern Australia

Fire management agencies undertake a range of fire management strategies to reduce the risk posed by future wildfires. This can include fuel treatments (prescribed burning and mechanical removal), suppression and community engagement. However, no agency has an unlimited budget and numerically optimal solutions can rarely be implemented, if indeed they do exist. Agencies are trying to quantify the extent to which their management actions reduce risk across multiple values in the most cost-effective manner. In this paper, we examine the cost-effectiveness of a range of prescribed burning strategies across multiple landscapes in south-eastern Australia. Landscapes considered include vegetated areas surrounding the cities of Hobart, Melbourne, Adelaide, Canberra and Sydney. Using a simulation approach, we examine the potential range of fires that could occur in a region with varying levels of edge and landscape prescribed burning treatment regimes. Damages to assets are measured for houses, lives, transmission lines, carbon and ecological assets. Costs of treatments are estimated from published models and all data are analysed using multi-criteria decision analysis. Cost-effectiveness of prescribed burning varies widely between regions. Variations primarily relate to the spatial configuration of assets and natural vegetation. Regions with continuous urban interface adjacent to continuous vegetation had the most cost-effective fuel treatment strategies. In contrast, those regions with fragmented vegetation and discontinuous interfaces demonstrated the lowest cost-effectiveness of treatments. Quantifying the extent to which fuel treatments can reduce the risk to assets is vital for determining the location and extent of treatments across a landscape.

Thermal Response of Timber Slabs Exposed to Travelling Fires and Traditional Design Fires

Engineered timber is an innovative and sustainable construction material, but its uptake has been hindered by concerns about its performance in fire. Current building regulations measure the fire performance of timber using fire resistance tests. In these tests, the charring rate is measured under a series of heat exposures (design fires) and from this the structural performance is deduced. Charring rates are currently only properly understood for the heat exposure of a standard fire, not for other exposures, which restricts the use of performance-based design. This paper studies the charring rates under a range of design fires. We used a multiscale charring model at the microscale (mg-samples), mesoscale (g-samples), and macroscale (kg-samples) for several wood species exposed to different heating regimes and boundary conditions. At the macroscale, the model blindly predicts in-depth temperatures and char depths during standard and parametric fires with an error between 5% and 22%. Comparing simulations of charring under travelling fires, parametric fires, and the standard fire revealed two findings. Firstly, their charring rates significantly differ, with maximum char depths of 42 mm (travelling), 46 mm (parametric), and 59 mm (standard fire), and one (standard fire) to four (travelling fire) charring stages (no charring, slow growth, fast growth, steady-state). Secondly, we observed zero-strength layers (depth between the 200 °C and 300 °C isotherm) of 7 to 12 mm from the exposed surface in travelling fires compared to 5 to 11 mm in parametric fires, and 7 mm in the standard fire. Both traditional design fires and travelling fires, therefore, need to be considered in structural calculations. These results help engineers to move towards performance-based design by allowing the calculation of charring rates for a wide range of design fires. In turn, this will help engineers to build more sustainable and safe structures with timber.

Flame shapes and thermal flux of vertical hydrocarbon flames

Hydrocarbon fuels are involved in most fire accidents occurring in industrial facilities, which may lead to catastrophic consequences in terms of life and property losses. The prediction of the related-fire effects can contribute to provide effective protection measures, hence mitigating the consequences of hydrocarbon flames in processing environments. In this regard, there is an essential need for developing state-of-the-art correlations able to accurately estimate the flame shapes and heat fluxes for a wide range of possible hydrocarbon fires. The present paper collects a vast data bank of vertical hydrocarbon fire experiments involving multiple fuels, burner diameters, mass flow rates and wind speeds. Correlations are developed, based on the data collected, to describe the flame-geometry descriptors and the heat fluxes of vertical hydrocarbon flames under different flow regimes.

대기행렬모형을 활용한 육군 박격포중대 운용방안연구

It is challenging to respond to multiple fire requests during military operations. Many studies have attempted to tackle this problem as an optimization problem for fire time scheduling that minimizes the firing time. Meanwhile, infantry mortars in the battle have many unexpected targets than scheduled targets due to short fire range. Besides, there are various limitations for mortar positions that provide enough firing space as a large portion of the Korean peninsula is mountainous. In this study, the operation of mortar company was analyzed through a priority queuing model to provide an efficient structure of the company that minimizes fire response time considering geological characteristics of operations encountered by the Korea Army. A simulation model was also given to apply our model to the real situation as well as verify the analytic model.

Protection of turbine halls of power plants from exposure to high temperatures in fire conditions

There are numerous cases when fires in power plant turbine halls causes the collapse of roof metal structures. The use of conventional firefighting equipment in high-bay facilities has proved to be ineffective or unacceptable. In this situation fire robots are the most feasible option. Today the best variant is a fire robot that is based on a traditional fire monitor and equipped with infrared fire seat detectors. Some specific advantages of fire robots include their ability to operate under low visibility with high smoke generation conditions that are typical of a fire in a turbine hall. The program of roof structures cooling down is designed and tested in advance so that fire robots can perform their functions in automatic mode. Fire robots can be included into permanent-type fire safety systems that are designed taking into account specific construction features of a facility and temperature conditions in case of a fire. Such composite system is a multifunctional complex that is able to perform versatile fire protection functions. The most appropriate fire robot types to be used in such complex fire protection system are fire robots based on conventional fire monitors, as they have some notable advantages compared with mobile robots or androids. One of them is their ability to protect big areas starting from 5 and up to 15 thousand square meters with fire suppressing media flow rate range just 20-60 l/sec correspondingly. Water or foam can be delivered via air exactly to the fire seat instead of spraying over the total designed area. Moreover, wetting intensity can be maintained at a level that corresponds to fire seat intensity.

Appearance and characteristics of the gunshot wounds caused by different fire weapons - animal model

Introduction/Objective. Gunshot residue (GSR) on the skin of a victim are important evidence, with far better precision, for reconstructive questions in the forensic investigation of cases involving gunshot wounds. The aim of this experimental study was to analyze if there was any significant difference in macroscopic characteristics of wounds that were caused with different types of weapons from three different distances. Methods. This study was conducted at the Department of Ballistic and Mechanoscopic Expertise, Federal Police Directorate. Experiments were done on pigskin and 55 samples were made. Shooting was conducted using a system for safe firing. Samples of the pigskin were shot by firing projectiles from four different weapons and from three different distances, (contact wound, five centimetres and 10 centimetres). Results. At the contact range, wounds caused by automatic rifle had horizontal, vertical diameters larger than those made by pistols. Diameters on the wounds that were caused with different pistols, were similar. At the range of five centimetres, the narrowest part of contusion ring significantly differs even through pistol wounds. Diameters at the range of 10 centimetres are in favor of these results. Gunpowder residue scattering area was statistically different depending of type of weapon (p = 0.004). Conclusion. Wound diameters and surface area are useful for differentiation between pistol and rifle caused wounds. It is unsecure method for determination of pistol caliber or fire range. GSR have much greater potential for future analyses, but even GSR cannot be used to determine pistol caliber.

Several Problems with Froude-Number Based Scale Modeling of Fires in Small Compartments

The Froude-number based reduced-scale modeling is a technique commonly used to investigate the flow of heat and mass in building fires. The root of the method is the thermodynamic model of a flow in a compartment and several non-dimensional flow numbers based on the proportionalities of the Navier-Stokes and heat transfer equations. The ratio of inertial forces to the buoyancy forces, known as the Froude-number, plays a pivotal role within these proportionalities. This paper is an attempt to define the range of credible scale modeling using the Froude-number. We verify the credibility of the modeling by small fire (approximately 150 kW) in a small compartment, comparing data from a physical test (scale 1:1 and 1:4) and the numerical model’s data (Fire Dynamics Simulator, scales 1:1, 1:2, 1:4, 1:10, 1:20, and 1:50). The scope of the research covers a wide range of fires, with observed change of the flow from turbulent to laminar. The results show that the applicability of Froude-number reduced-scale modeling has limitations related to the scale. Therefore, it should be applied with care following sensibility analysis. We propose a method for sensibility analysis using Computational Fluid Dynamics (CFD) modeling.

Switchboard Fire Detection System Using Expert Inference Method Based on Improved Fire Discrimination

This paper proposes a switchboard fire detection system that uses the expert inference method based on improved fire probability for accurate fire identification. The conventional expert inference method has a disadvantage in that the range of the evaluation index for fire probability is limited because the defuzzification process uses a quantified set shape. To overcome this problem, we propose an improved expert inference method that uses a defuzzification correction operation after defuzzification. This technique applies a quadratic function to a range of reduced fire potentials, and then gradually expands the reduced range. The fire probability range was expanded using the improved expert inference method with the defuzzification correction operation, which also extended the fire detection range. As a result, it is expected that the fire awareness of this watchdog can be improved by the defuzzification correction operation.

Simulation study of fire spread range & speed according to the characteristics of the region

Simulation study of fire spread range & speed according to the characteristics of the region

Comparative Population Genetics of Red Imported Fire Ants (Solenopsis invicta) at the University of Central Oklahoma and Lake Arcadia, Edmond, Oklahoma

The red imported fire ant is a well-studied pest in the southern United States, but investigations of invasions in the central region are relatively rare. We compared two central Oklahoma invasions: a newly observed urban invasion on the campus of the University of Central Oklahoma, and an established invasion around Lake Arcadia. We genotyped the General protein-9 (Gp-9) locus to determine social form and eleven microsatellites to evaluate population structure. We hypothesized that colonies were polygyne, that the repeated introductions required to reach central Oklahoma would lead to low genetic diversity, and that the two sites were independently colonized and, therefore, would be genetically isolated. As expected, the analysis of 33 sampled colonies showed that almost all were polygyne and exhibited low genetic diversity, although comparable to diversity found in previous studies. Contrary to our original hypothesis, we discovered that the two separate invasion sites of our study are not differentiated from each other. We found no evidence of distinct genetic clusters within or across sites. However, we did find evidence of two or more introductions that have become integrated. The potential for contemporary gene flow near the northern edge of the fire ant range is concerning as it allows for the maintenance of genetic variation that can lead to more effective adaptation to new environments.

Composition and Structure of Forest Fire Refugia: What Are the Ecosystem Legacies across Burned Landscapes?

Locations within forest fires that remain unburned or burn at low severity—known as fire refugia—are important components of contemporary burn mosaics, but their composition and structure at regional scales are poorly understood. Focusing on recent, large wildfires across the US Pacific Northwest (Oregon and Washington), our research objectives are to (1) classify fire refugia and burn severity based on relativized spectral change in Landsat time series; (2) quantify the pre-fire composition and structure of mapped fire refugia; (3) in forested areas, assess the relative abundance of fire refugia and other burn severity classes across forest composition and structure types. We analyzed a random sample of 99 recent fires in forest-dominated landscapes from 2004 to 2015 that collectively encompassed 612,629 ha. Across the region, fire refugia extent was substantial but variable from year to year, with an annual mean of 38% of fire extent and range of 15–60%. Overall, 85% of total fire extent was forested, with the other 15% being non-forest. In comparison, 31% of fire refugia extent was non-forest prior to the most recent fire, highlighting that mapped refugia do not necessarily contain tree-based ecosystem legacies. The most prevalent non-forest cover types in refugia were vegetated: shrub (40%), herbaceous (33%), and crops (18%). In forested areas, the relative abundance of fire refugia varied widely among pre-fire forest types (20–70%) and structural conditions (23–55%). Consistent with fire regime theory, fire refugia and high burn severity areas were inversely proportional. Our findings underscore that researchers, managers, and other stakeholders should interpret burn severity maps through the lens of pre-fire land cover, especially given the increasing importance of fire and fire refugia under global change.

Use of Minicameras to Improve Operative Procedure in Security Forces.

The aim of the present study was to analyze pistol and compact rifle marksmanship in close quarter combat (CQC). There is currently a controversy about what weapon is most appropriate to use in CQC, short weapon as pistols or long weapons as rifle. Forty two participants conducted two close quarter combat simulations, one with pistol and one with compact rifle. Marksmanship and time to cover the simulation were measured. Data obtained showed no significant differences between pistol and compact rifle. In addition, it was observed a tendency to obtain higher scores with compact rifle, probably be due to the higher stability provided in the shot action. Compact rifle could be an effective election in actual theaters of operation in which asymmetrical and symmetrical combat are combined and also in police interventions due to compact rifle provide higher fire power and range and obtained the same shooting performance than pistol. To the best of our knowledge this is the first study that provides empirical data to solve the discussion about the efficiency of the use of rifle and pistol in close quarter combat in military and police interventions. These results could be used to improve the military and police interventions efficiency.

Computational Approach to Identify Different Injuries by Firearms.

Complications arise in the analysis of gunshot wounds to the maxillofacial region, when neither the projectile nor the gun is found at the crime scene. We simulated 5- and 15-cm firing distances at a human mandible to investigate the external morphology of entrance wounds based on fire range. The ammunition models, .40-caliber S&W, .380-caliber, and 9×19-mm Luger, were constructed with free-form NURBS surfaces. In a dynamic simulation, projectiles were fired against mandibular body 3D model at 5 and 15cm. All entrance wounds presented oval aspect. Maximum diameter and von Mises stress values were 16.5mm and 50.8MPa, both for .40-caliber S&W fired at 5cm. The maximum energy loss was 138.4J for .40 S&W fired at 15cm. In conclusion, the mandible was most affected by .40-caliber S&W and morphological differences were observable in holes caused by different incoming projectile calibers fired at different distances.

Historical and future fire occurrence (1850 to 2100) simulated in CMIP5 Earth System Models

Earth System Models (ESMs) have recently integrated fire processes in their vegetation model components to account for fire as an important disturbance process for vegetation dynamics and agent in the land carbon cycle. The present study analyses the performance of ESMs that participated in the 5th Coupled Model Intercomparison Project (CMIP5) in simulating historical and future fire occurrence. The global present day (1981 to 2005) burned area simulated in the analysed ESMs ranges between 149 and 208Mha, which is substantially lower than the most recent observation based estimate of 399Mha (GFEDv4s averaged over the time period 1997 to 2015). Simulated global fire carbon emissions, however, are with 2.0PgC/year to 2.7PgC/year on the higher end compared to the GFEDv4s estimate of 2.2PgC/year. Regionally, largest differences are found for Africa. Over the historical period (1850 to 2005) changes in simulated fire carbon emissions range between an increase of +43% and a decrease of −35%. For the future (2005 to 2100) we analysed the CMIP5 simulations following the representative concentration pathways (RCPs) 26, 45, and 85, for which the strongest changes in global fire carbon emissions simulated in the single ESMs amount to +8%, +52% and +58%, respectively. Overall, however, there is little agreement between the single ESMs on how fire occurrence changed over the past or will change in the future. Furthermore, contrasting simulated changes in fire carbon emissions and changes in annual mean precipitation shows no emergent pattern among the different analysed ESMs on the regional or global scale. This indicates differences in the single fire model representations that should be subject of upcoming fire model intercomparison studies. The increasing information derived from observational datasets (charcoal, ice-cores, satellite, inventories) will help to further constrain the trajectories of fire models.

COLLAPSE RISK PREDICTION OF BUILDINGS ON FIRE USING KEY ELEMENT INDEX

It is difficult to estimate the redundant strength remaining in a building on fire, since the fire conditions such as their ranges and locations may be different in each case. A large-scale fire occurred on the New York World Trade Center 7 (WTC-7) after the 9.11 terrorist attacks in 2001. The building continued to burn for 7 hours, and ended in a total collapse. The official report on the collapse investigation of WTC-7, released by the National Institute of Standards and Technology (NIST) in 2005, had suggested that the total collapse was triggered by a severe damage of an important column of the building called the key element. On the other hand, there is also an example of a high-rise building on fire that avoided a total collapse, regardless of its main structure continuously heated by fire for a long time; the Windsor building of Madrid in 2005. From the viewpoint of preventing the fire-induced collapse of buildings, it is necessary to clarify the relationship between various structural parameters of buildings, fire locations, their ranges, and the scale of collapse. The purpose of this study is to predict collapse risks of buildings on fire using a key element index (KI). The KI is defined as the ratio of the ultimate yield strengths of the structure with one column eliminated and the initial, undamaged structure. It indicates the contribution of a structural column to the vertical capacity of the structure. We investigated the relationship between the sum of KI values in various cases of fire range and the sum of the height of remains after the collapse. We applied an adaptively shifted integration (ASI) - Gauss code utilizing linear Timoshenko beam elements to investigate the collapse behaviors of a ten-story steel framed building model with various fire patterns. Fracture contact, contact release and re-contact algorithms were implemented in the code. The reduction curves of elastic modulus and yield strength of steel related to elevated temperature, shown by NIST, were adopted to consider the heat effect of fire. Thermal expansion of materials was also considered. From the numerical results of the fire-induced collapse analyses, it is found that the scale of collapse highly depends on fire ranges and locations. The risk of total collapse tends to increase when a large range of fire occurs in the lower layer. In addition, the risk increases much higher in those cases when fire occurs at the peripheral area of the building, compared to those cases at the inner area. The sum of heights of remains seems to depend on the sum of KI values, and there is a specific threshold of the sum of KI values that relates to the initiation of a large scale collapse. Therefore, the sum of KI values may be used to predict and take measures to avoid the risk of collapse under various fire conditions.

Long-Term Trends of Northern Bobwhite Populations and Hunting Success on Private Shooting Plantations in Northern Florida and Southern Georgia

Nearly all broad-scale assessments (U.S. Department of the Interior, Fish and Wildlife Service [USDI-FWS], Breeding Bird Surveys, Audubon Society Christmas Bird Counts, and state game agency harvest surveys) of northern bobwhite (Colinus virginianus) population trends during the past 30 to 50 years point to widespread declines at local, regional and national scales. Long-term records of populations that do not show long-term bobwhite declines are rare. Landowners and managers in the shooting plantation country between Tallahassee, Florida and Thomasville, Georgia have been recording quail hunting and bag records for many years. Such information can provide valuable insight into the long-term trends of bobwhite populations. We therefore analyzed bag records from 5 different properties where data had been collected for periods ranging from 14 to 80+ years. Trends from these data were completely opposite from long-term trends shown from other sources such as Breeding Bird Survey and Christmas Bird Count data. These data indicate that a long-term, continuous approach to habitat management (primarily burning with prescribed fire, and frequent soil disturbance from disking) can sustain abundant bobwhite populations and high-quality shooting. These data also call into question alternative hypotheses such as invasion of the red imported fire ant and range expansion of the coyote as being responsible for the long-term bobwhite decline. Both fire ants and coyotes are common in the Thomasville-Tallahassee area, yet, abundant bobwhite populations persist, presumably as a function of high-quality habitat management.

Reconstrucción del historial de incendios y estructura forestal en bosques mixtos de pino-encino en la Sierra Madre Oriental

Los incendios forestales en México han tenido gran relevancia después de la temporada de incendios en 1998 debido a su contribución directa a la deforestación, el cambio en la estructura y composición del bosque. Además recientemente se considera su participación directa en el incremento de bióxido de carbono en la atmósfera. Sin embargo, es muy escaso el conocimiento que se posee acerca de los efectos de los incendios sobre la estructura, composición y dinámica de los bosques de la Sierra Madre Oriental (SMO). En este trabajo, se presenta una cronosecuencia de incendios forestales (134 años) determinada a través del análisis de anillos de crecimiento en cohortes post-incendio con diferentes edades. Los objetivos del estudio fueron: (1) establecer y determinar el rango histórico de la ocurrencia de incendios forestales, (2) evaluar parámetros dendrométricos para conocer la estructura presente y así establecer sitios de referencia para programas de restauración ecológica y (3) incrementar nuestro conocimiento en los procesos de disturbio en los bosques mixtos de pino-encino en la SMO. El estudio revela que existieron diferencias significativas entre las cohortes post incendios en términos de riqueza de especies, composición y estructura del rodal. La estructura forestal fue menos diversa en rodales jóvenes comparados con los intermedios, maduros y sobremaduros. Una alta diversidad de especies arbóreas fue generalmente encontrada en rodales jóvenes, mientras que en los rodales intermedios y maduros mostraron la diversidad más baja.

Thermal explosion in oscillating ambient conditions.

Thermal explosion problem for a medium with oscillating ambient temperature at its boundaries is considered. This is a new problem in thermal explosion theory, not previously considered in a distributed system formulation, but important for combustion and fire science. It describes autoignition of wide range of fires (such as but not limited to piles of biosolids and other organic matter; storages of munitions, explosives, propellants) subjected to temperature variations, such as seasonal or day/night variation. The problem is considered in formulation adopted in classical studies of thermal explosion. Critical conditions are determined by frequency and amplitude of ambient temperature oscillations, as well as by a number of other parameters. Effects of all the parameters on critical conditions are quantified. Results are presented for the case of planar symmetry. Development of thermal explosion in time is also considered, and a new type of unsteady thermal explosion development is discovered where thermal runaway occurs after several periods of temperature oscillations within the medium.