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1
Willems, Gertjan. "Le Bien contre le Mal contre Claus". Emulations - Revue de sciences sociales, n. 16 (7 aprile 2016): 53–65. http://dx.doi.org/10.14428/emulations.016.010.
Testo completoAbstract (sommario):
Cet article analyse le film Le Lion des Flandres (Hugo Claus, 1984), en se basant sur une analyse de textes et sur l’exploitation d’archives. Il se concentre sur les relations complexes que ce film entretient avec la question nationale belge et flamande. Cette coproduction flamande et néerlandaise (également adaptée en série télévisée en 1985) est une adaptation du roman historique romantique du même nom d'Hendrik Conscience, publié en 1838, une œuvre marquante dans l'histoire culturelle et symbolique du Mouvement flamand. Malgré diverses difficultés liées au caractère nationalise flamand de l’œuvre de Conscience, les producteurs (dont le ministère flamand de la Culture et la télévision publique de la Communauté flamande) voulaient que le film soit le plus fidèle possible au roman de Conscience. Il en a résulté une production ouvertement romantique et nationaliste flamande et ce, en dépit de quelques contrepoints introduits par le directeur de production Hugo Claus ; un personnage controversé et critiqué mais néanmoins reconnu comme étant extrêmement rigoureux. Bien que Le Lion ait été la production belge néerlandophone la plus coûteuse, le film s'est avéré un échec critique et commercial sans précédent.
2
Lin, Shaorun, Peiyi Sun e Xinyan Huang. "Can peat soil support a flaming wildfire?" International Journal of Wildland Fire 28, n. 8 (2019): 601. http://dx.doi.org/10.1071/wf19018.
Testo completoAbstract (sommario):
Smouldering wildfire in peatlands is one of the largest and longest-lasting fire phenomena on Earth, but whether peat can support a flaming fire like other surface fuels is still unclear. Our experiments demonstrate the successful piloted flaming ignition of peat soil with moisture up to 100 wt-% under external radiation, indicating that flames may rapidly spread on peatland before transitioning to a conventional smouldering peat fire. Compared with smouldering ignition, flaming ignition of peat is more difficult, requiring a higher minimum heat flux and tripling the ignition energy. The propensity for flaming increases with a drier peat and greater external heating. We also found that the flaming ignition temperature increases from 290 to 690°C as the peat moisture increases to 100 wt-%. Flames from peat soil are much weaker than those of pine needles and wood, and they eventually transition to smouldering. The heat of flaming is estimated to be 13MJkg−1, close to the heat of smouldering. The measured CO/CO2 ratio of flaming peat fires is less than 0.02, much smaller than 0.2 for smouldering peat fires. This research helps understand the development of peat fire and the interaction between flaming and smouldering wildland fires.
3
Gowlett, J. A. J. "Flaming fronts of fire". Nature 350, n. 6318 (aprile 1991): 539. http://dx.doi.org/10.1038/350539a0.
Testo completo
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Nadeem, Muhammad, Naqqash Dilshad, Norah Saleh Alghamdi, L. Minh Dang, Hyoung-Kyu Song, Junyoung Nam e Hyeonjoon Moon. "Visual Intelligence in Smart Cities: A Lightweight Deep Learning Model for Fire Detection in an IoT Environment". Smart Cities 6, n. 5 (28 agosto 2023): 2245–59. http://dx.doi.org/10.3390/smartcities6050103.
Testo completoAbstract (sommario):
The recognition of fire at its early stages and stopping it from causing socioeconomic and environmental disasters remains a demanding task. Despite the availability of convincing networks, there is a need to develop a lightweight network for resource-constraint devices rather than real-time fire detection in smart city contexts. To overcome this shortcoming, we presented a novel efficient lightweight network called FlameNet for fire detection in a smart city environment. Our proposed network works via two main steps: first, it detects the fire using the FlameNet; then, an alert is initiated and directed to the fire, medical, and rescue departments. Furthermore, we incorporate the MSA module to efficiently prioritize and enhance relevant fire-related prominent features for effective fire detection. The newly developed Ignited-Flames dataset is utilized to undertake a thorough analysis of several convolutional neural network (CNN) models. Additionally, the proposed FlameNet achieves 99.40% accuracy for fire detection. The empirical findings and analysis of multiple factors such as model accuracy, size, and processing time prove that the suggested model is suitable for fire detection.
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Huang, Yang Cheng, e Zhao Yi He. "Study on Properties and Pavement Performance of Anti-Flaming and Warm-Mix SBS Modified Asphalt". Applied Mechanics and Materials 97-98 (settembre 2011): 367–72. http://dx.doi.org/10.4028/www.scientific.net/amm.97-98.367.
Testo completoAbstract (sommario):
In order to solve problems such as environmental contamination, large resource consuming, and the inflammability of present asphalt mixture, a warm-mix agent was chosen and fire retardant was added to asphalt to modify its characteristics. The anti-flaming and warm-mix asphalt has been produced in the orthogonal experiment, and its road property and anti-flaming property lived up to expectation. The experiment shows that under the condition of a lower temperature (15-20°C lower than the the mix temperature), the rutting resistance of the anti-flaming and warm-mix SBS modified asphalt , but its low temperature property and water sensitivity decreased. This asphalt has excellent anti-flaming characteristic, and thus it can decrease the property loss in case of fire.
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Aleshkov, M. V., V. P. Molchanov, S. A. Makarov, D. A. Ioschenko, A. V. Tretyakov, V. V. Bareshkin e R. B. Bituyev. "Using air-filled foam to contain and liquidate the flaming combustion of liquefied natural gas spills". Pozharovzryvobezopasnost/Fire and Explosion Safety 31, n. 5 (11 novembre 2022): 67–82. http://dx.doi.org/10.22227/0869-7493.2022.31.05.67-82.
Testo completoAbstract (sommario):
Introduction. Using air-filled foam to contain and liquidate the flaming combustion of liquefied natural gas spills is one of the most optimal methods of preventing the escalation of emergencies. However, the amount of data available today is insufficient to standardize the basic parameters of air-filled foam injection.The purpose of this research project is to justify the application of air-filled foam to contain and liquidate the flaming combustion of liquefied natural gas and identify the basic parameters of injection. The following objectives are to be attained towards this end: assessment of the fire and explosion safety of liquefied natural gas and analysis of extinguishing means applicable to spills; experimental determination of the insulating ability of foams, having different expansion factors, if applied to the surface of cryogenic fluid; experimental determination of the fire-fighting efficiency of the foam used to liquidate the flaming combustion of liquefied natural gas; experimental verification of expediency of the joint application of high expansion air-filled foam and extinguishing powders.Results and discussion. Having discussed the findings of the in-house experiments and analyzed the international and domestic tests conducted for this purpose, the authors assume that the application of the foam, whose expansion factor equals 300 to 500 units, can effectively contain and liquidate the flaming combustion of liquefied natural gas. The flaming combustion cannot be liquidated, if lower expansion factor foams are applied. The application rate of the high-expansion air-filled foam, exceeding 0.08 kg/(m2·s), is required to reduce the intensity of flaming combustion. Flaming combustion can be efficiently liquidated if the application rate of high-expansion air-filled foam is set at 0.17 ± 0.01 kg/(m2·s). Fire-extinguishing powders can only be efficiently applied to liquidate the flaming combustion of liquefied natural gas, if its surface is covered in foam.Conclusions. The authors have used their in-house experimental data, analyzed the literary sources and wellknown properties of the fire-extinguishing foam to justify the basic parameters of foam application aimed at the containment and liquidation of the flaming combustion of liquefied natural gas.
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Schiks, T. J., e B. M. Wotton. "Assessing the probability of sustained flaming in masticated fuel beds". Canadian Journal of Forest Research 45, n. 1 (gennaio 2015): 68–77. http://dx.doi.org/10.1139/cjfr-2014-0294.
Testo completoAbstract (sommario):
Mechanical mastication is increasingly used as a fuel management treatment to reduce fire risk at the wildland–urban interface, although ignition and fire behaviour in these novel fuel beds are poorly understood. We investigated the influence of observed fuel moisture content, wind speed, and firebrand size on the probability of sustained flaming of masticated fuel beds under both laboratory and field settings. Logistic regression techniques were applied to assess the probability of sustained flaming in both datasets. Models for the field were also developed using estimated moisture from three sets of weather-based models: (i) the hourly Fine Fuel Moisture Code (FFMC) from the Canadian Forest Fire Weather Index System, (ii) the National Fire Danger Rating System (NFDRS) moisture estimates for 1 h and 10 h fuels, and (iii) a masticated surface fuel moisture model (MAST). In both laboratory and field testing, the likelihood of a successful ignition increased with decreasing moisture content and increasing wind speed; the effect of firebrand size was only apparent in laboratory testing. The FFMC, NFDRS, and MAST predictions had somewhat reduced discriminative power relative to direct moisture in predicting the probability of sustained flaming based on our field observations. Our results speak to the disparity between the fire behaviour modeling that occurs in the laboratory and the fire behavior modeling that occurs in the field, as the methodology permitted comparison of predictions from sustained flaming models that were developed for one experimental setting and applied to the other.
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Huda, Quamrul, David Lyder, Marty Collins, Dave Schroeder, Dan K. Thompson, Ginny Marshall, Alberto J. Leon, Ken Hidalgo e Masum Hossain. "Study of Fuel-Smoke Dynamics in a Prescribed Fire of Boreal Black Spruce Forest through Field-Deployable Micro Sensor Systems". Fire 3, n. 3 (12 luglio 2020): 30. http://dx.doi.org/10.3390/fire3030030.
Testo completoAbstract (sommario):
Understanding the combustion dynamics of fuels, and the generation and propagation of smoke in a wildland fire, can inform short-range and long-range pollutant transport models, and help address and mitigate air quality concerns in communities. Smoldering smoke can cause health issues in nearby valley bottoms, and can create hazardous road conditions due to low-visibility. We studied near-field smoke dynamics in a prescribed fire of 3.4 hectares of land in a boreal black spruce forest in central Alberta. Smoke generated from the fire was monitored through a network of five field-deployable micro sensor systems. Sensors were placed within 500–1000 m of the fire area at various angles in downwind. Smoke generated from flaming and smoldering combustions showed distinct characteristics. The propagation rates of flaming and smoldering smoke, based on the fine particulate (PM2.5) component, were 0.8 and 0.2 m/s, respectively. The flaming smoke was characterized by sharp rise of PM2.5 in air with concentrations of up to 940 µg/m3, followed by an exponential decay with a half-life of ~10 min. Smoldering combustion related smoke contributed to PM2.5 concentrations above 1000 µg/m3 with slower decay half-life of ~18 min. PM2.5 emissions from the burn area during flaming and smoldering phases, integrated over the combustion duration of 2.5 h, were ~15 and ~16 kilograms, respectively, as estimated by our mass balance model.
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Li, Gang, Fang Qu, Zhi Wang, Xuhai Xiong e Yanying Xu. "Experimental Study of Thermal and Fire Reaction Properties of Glass Fiber/Bismaleimide Composites for Aeronautic Application". Polymers 15, n. 10 (11 maggio 2023): 2275. http://dx.doi.org/10.3390/polym15102275.
Testo completoAbstract (sommario):
Thermal behavior and fire reaction properties of aerial glass fiber (GF)/bismaleimide (BMI) composites were tested using thermogravimetric analysis (TGA), thermogravimetric coupled with Fourier transform infrared spectroscopy (TG-FTIR), cone calorimeter, limiting oxygen index, and smoke density chamber. The results showed that the pyrolysis process was one stage in a nitrogen atmosphere with the prominent volatile components of CO2, H2O, CH4, NOx, and SO2. The release of heat and smoke increased with the increase in heat flux, while the time required to reach hazardous conditions decreased. The limiting oxygen index decreased monotonically from 47.8% to 39.0% with increasing experimental temperature. The maximum specific optical density within 20 min in the non-flaming mode was greater than that in the flaming mode. According to the four kinds of fire hazard assessment indicators, the greater the heat flux, the higher the fire hazard, for the contribution of more decomposed components. The calculations of two indices confirmed that the smoke release in the early stage of fire was more negative under flaming mode. This work can provide a comprehensive understanding of the thermal and fire characteristics of GF/BMI composites used for aircraft.
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Aleshkov, Mikhail V., Viktor P. Molchanov, Sergey A. Makarov, Dmitry A. Ioshchenko, Rashid B. Bituev e Aleksey V. Tretyakov. "Determining critical foam layer thickness for localization and elimination of liquefied natural gas spills flame combustion". Fire and Emergencies: prevention, elimination 3 (2023): 5–14. http://dx.doi.org/10.25257/fe.2023.3.5-14.
Testo completoAbstract (sommario):
PURPOSE. Increasing attention has been paid recently to applying high-expansion foam as means of localizing and eliminating liquefied natural gas spills flaming combustion. Scientific sources widely discuss the issues of foam expansion rate and elasticity, critical intensity of its supply and application rate. However, critical foam layer thickness is underestimated. At the same time one of the reasons for fire-fighting foam low efficiency is precisely the difficulty in providing required foam layer thickness. The purpose of this publication is to assess relationship between critical foam layer thickness and main parameters of localizing and eliminating liquefied natural gas flaming combustion. METHODS. Review of scientific works covering the issue of flammable liquids and liquefied natural gas foam fire extinguishment has been carried out. Methods for providing required foam layer thickness and determining foam fire extinguishing efficiency are analyzed. Results of researchers’ own experiments have been discussed, taking into account international and domestic experience in conducting similar studies. FINDINGS. Based on researchers’ own experimental data analysis, taking into account information from scientific sources, critical foam layer thickness assessment has been made for foams of various expansions used to localize and eliminate liquefied natural gas spills flaming combustion. Approximate foam layer thickness in centimeters should be at least a quarter of high-expansion foam expansion value. RESEARCH APPLICATION FIELD. The results obtained provide general understanding that to ensure efficiency of liquefied natural gas flaming combustion localization and elimination, it is necessary to ensure not only appropriate foam expansion and application rate, but also required foam layer thickness. The results can be used in scientific research and educational process, as well as by fire services and emergency rescue units in elimination of accidents accompanied by liquefied natural gas spills flaming combustion. CONCLUSIONS. Foam layer thickness is the key parameter for liquefied natural gas spills foam fire extinguishment and providing controlled burning technology. Depending on foam supply intensity the necessary condition for providing liquefied natural gas flaming combustion localization and elimination is to achieve or exceed critical foam layer thickness. Critical foam layer thickness depends on foam expansion ratio. As foam expansion ratio increases, critical foam layer thickness rises, its value can exceed two or more meters.
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Beverly, Jennifer L., e B. Mike Wotton. "Modelling the probability of sustained flaming: predictive value of fire weather index components compared with observations of site weather and fuel moisture conditions". International Journal of Wildland Fire 16, n. 2 (2007): 161. http://dx.doi.org/10.1071/wf06072.
Testo completoAbstract (sommario):
We investigated the likelihood that short-duration sustained flaming would develop in forest ground fuels that had direct contact with a small and short-lived flame source. Data from 1027 small-scale experimental test fires conducted in field trials at six sites in British Columbia and the North-West Territories between 1958 and 1961 were used to develop logistic regression models for ten fuel categories that represent unique combinations of forest cover, ground fuel type, and in some cases, season. Separate models were developed using two subsets of independent variables: (1) weather variables and fuel moisture measurements taken at the site of the test fire; and (2) Canadian Fire Weather Index (FWI) system components calculated from weather observations recorded at a nearby station. Results indicated that models developed with FWI system components were as effective as models developed with site variables at predicting the probability of short-duration sustained flaming in most fuel categories. FWI system components were not useful for predicting sustained flaming in spring grass fuels and had limited usefulness for modelling the probability of sustained flaming in aspen leaf ground fuels during summer conditions. For all other fuel categories, FWI system components were highly effective substitutes for site variables for modelling the probability of sustained flaming.
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Ittzes Abrams, Zsuzsanna. "Flaming in CMC: Prometheus' Fire or Inferno's?" CALICO Journal 20, n. 2 (14 gennaio 2013): 245–60. http://dx.doi.org/10.1558/cj.v20i2.245-260.
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He, Zhao Yi, Yang Cheng Huang e Gang Huang. "Study on Properties and Pavement Performance of Anti-Flaming and Warm-Mix Asphalt". Applied Mechanics and Materials 71-78 (luglio 2011): 803–8. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.803.
Testo completoAbstract (sommario):
In order to solve the problems of environmental contamination, large resource consuming and inflammability of asphalt mixture, this research chooses warm-mix agent and fire retardant to double modify the asphalt. After obtain the method to produce the anti-flaming and warm-mix asphalt through orthogonal experiment, its road property and anti-flaming property are valued. According to the experiment result, under the condition of cooling down 30°C of the mix temperature, the modified anti-flaming and warm-mix asphalt can increase the high temperature property of the asphalt mixture, but decrease the low temperature property and water stability characteristic of it. This asphalt has excellent anti-flaming characteristic, so it can decrease the property loss after being burnt.
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Mišić, Nikola, e Milan Protić. "Evaluating fire effluents during combustion of wood boards". Safety Engineering 10, n. 2 (2020): 85–88. http://dx.doi.org/10.5937/se2002085m.
Testo completoAbstract (sommario):
Effluents generated during the flaming as well as non-flaming burning of materials may be regarded as the main cause of death and injuries from fires. The structure of fire gases highly depends on the physical condition and chemistry of fuel as well as burning conditions. During the combustion of organic materials, complex mixtures of fire gases may be created. This paper investigates fire effluent yields during the well-ventilated burning tests of lumber products - board samples from two common wood species: oak and fir. Experiments were performed in custom-designed laboratory installation hyphenating mass loss calorimeter (with chimney and thermopiles for heat release rate measurement) and FTIR gas analyzer for subsequent on-line analysis of evolved fire gases. Tests were conducted with two different heat fluxes: 30 and 40 kW/m2 . The focus was on continuous emission monitoring of three principal fire gas components: H2O, CO2, and CO with a particular emphasis on CO rates.
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Karpovič, Zbignev, Ritoldas Šukys e Rimvydas Gudelis. "TOXICITY RESEARCH OF SMOULDERING AND FLAMING PINE TIMBER TREATED WITH FIRE RETARDANT SOLUTIONS". Journal of Civil Engineering and Management 18, n. 4 (11 settembre 2012): 600–608. http://dx.doi.org/10.3846/13923730.2012.709195.
Testo completoAbstract (sommario):
The emission of toxic gaseous combustion products from timber constructions influences on the time required for evacuation of people from a building during a fire. In order to prolong the time interval until inflammation of timber constructions, fire retardant solutions are used. It is relevant and very important to determine how the emission of toxic gaseous combustion products from pine timber non-treated and treated with fire retardant solutions used in Lithuania differs during thermal destruction. Measuring carbon monoxide (CO) emissions, the paper focuses on toxicity analysis determined by nonstandard and standard research methods of smouldering and flaming pine timber, both non-treated and treated with fire retardant solutions. The description comprises specimens used in research and their preparation, nonstandard and standard research equipment and methods determining toxicity of smouldering and flaming pine timber, both non-treated and treated with fire retardant solutions. The article presents the analysis of experimental results processed by statistical methods.
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Palamba, P., A. S. Werdhani e J. J. Numberi. "Smoldering behavior of peat fire". IOP Conference Series: Earth and Environmental Science 1192, n. 1 (1 giugno 2023): 012039. http://dx.doi.org/10.1088/1755-1315/1192/1/012039.
Testo completoAbstract (sommario):
Abstract This research is conducted to study the effect of airflow rate on the smoldering combustion dynamics and transition to flaming. The test is done using three types of peat extracted from South Sumatera, Central Kalimantan, and Papua Provinces, Indonesia. The combustion is carried out on natural, 1.33 cm/s, 3.98 cm/s, and 6.63 cm/s of airflow, respectively, representing the oxidation with lack and excess of air as calculated by stoichiometric equilibrium. For Central Kalimantan and Papuan Peat, the smoldering spread rate tends to increase with increasing the air supply. While in South Sumatran Peat, it begins to decrease at the air velocity of 6.63 cm/s. Differences in physical properties yield the difference in the smoldering dynamic behavior. In general, a higher airflow velocity leads to higher smoldering temperature, spread rate, and mass loss rate. Combustion with natural air and lack of oxygen will result in smoldering whereas excess air led to a transition to flaming.
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Babrauskas, Vytenis. "Effective heat of combustion for flaming combustion of conifers". Canadian Journal of Forest Research 36, n. 3 (1 marzo 2006): 659–63. http://dx.doi.org/10.1139/x05-253.
Testo completoAbstract (sommario):
The heat of combustion of burning trees is often used in forest-fire hazard modeling to relate mass-loss results to the heat produced; therefore reliable values are needed. Experimental results for the effective heat of combustion of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees are presented as a function of moisture content. It is also shown that during a forest fire, the effective heat of combustion does not correspond to the oxygen-bomb-test value. Instead, the value will always be lower, since the heat of combustion of char is higher than that of the pyrolysate vapors, and char mostly remains unburned during a forest fire. These are the first and only experimental results obtained from testing of actual trees. But results from benchmark testing and studies on wood products by other investigators are broadly consistent with our findings. It is further shown that moisture content has a major effect on the effective heat of combustion. A quantitative expression for the effective heat of combustion, as a function of moisture content, is obtained. Benchmark testing by earlier researchers established that generally there is only a slight species effect on the heat of combustion; therefore the present Douglas-fir results can be applied in more general forest-fire modeling.
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Krix, Daniel W., e Brad R. Murray. "A Predictive Model of Leaf Flammability Using Leaf Traits and Radiant Heat Flux for Plants of Fire-Prone Dry Sclerophyll Forest". Forests 13, n. 2 (20 gennaio 2022): 152. http://dx.doi.org/10.3390/f13020152.
Testo completoAbstract (sommario):
The differential flammability of individual plant species in landscape-scale fire behaviour is an important consideration, but one that is often overlooked. This is in part due to a relative dearth in the availability of plant flammability data. Here, we present a highly accurate predictive model of the likelihood of plant leaves entering flaming combustion as a function of leaf mass per area (LMA), leaf area (LA) and radiant heat flux using species of fire-prone dry sclerophyll forests of south-eastern Australia. We validated the performance of the model on two separate datasets, and on plant species not included in the model building process. Our model gives accurate predictions (75–84%) of leaf flaming with potential application in the next generation of fire behaviour models. Given the global wealth of species’ data for LMA and LA, in stark contrast to leaf flammability data, our model has the potential to improve understanding of forest flammability in the absence of leaf flammability information.
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Mercer, GN, e RO Weber. "Plumes Above Line Fires in a Cross-Wind". International Journal of Wildland Fire 4, n. 4 (1994): 201. http://dx.doi.org/10.1071/wf9940201.
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A model for the plume above a line fire in a cross wind is constructed. This problem is shown to reduce to numerically solving a system of 6 coupled ordinary differential equations for given initial conditions that depend upon the fire characteristics. The model is valid above the flaming zone and takes inputs such as the width, velocity and temperature of the plume at a given height above the flaming zone, Different horizontal ambient wind velocities are allowed for and a comparison is made between some of these representative wind profiles. The plume trajectory, width, velocity and temperature are calculated for these different representative velocity profiles. This model has application to the calculation of temperature-time exposures of vegetation above line fires and hence can be used in models that predict effects such as leaf scorch and canopy stored seed death. On a larger scale it has application to the problem of tracking burning brands which can cause spotting ahead of the fire.
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Ahmed, Mohamed Mohsen, Arnaud Trouvé, Jason Forthofer e Mark Finney. "Simulations of flaming combustion and flaming-to-smoldering transition in wildland fire spread at flame scale". Combustion and Flame 262 (aprile 2024): 113370. http://dx.doi.org/10.1016/j.combustflame.2024.113370.
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Liu, Yongqiang, Adam Kochanski, Kirk R. Baker, William Mell, Rodman Linn, Ronan Paugam, Jan Mandel et al. "Fire behaviour and smoke modelling: model improvement and measurement needs for next-generation smoke research and forecasting systems". International Journal of Wildland Fire 28, n. 8 (2019): 570. http://dx.doi.org/10.1071/wf18204.
Testo completoAbstract (sommario):
There is an urgent need for next-generation smoke research and forecasting (SRF) systems to meet the challenges of the growing air quality, health and safety concerns associated with wildland fire emissions. This review paper presents simulations and experiments of hypothetical prescribed burns with a suite of selected fire behaviour and smoke models and identifies major issues for model improvement and the most critical observational needs. The results are used to understand the new and improved capability required for the next-generation SRF systems and to support the design of the Fire and Smoke Model Evaluation Experiment (FASMEE) and other field campaigns. The next-generation SRF systems should have more coupling of fire, smoke and atmospheric processes. The development of the coupling capability requires comprehensive and spatially and temporally integrated measurements across the various disciplines to characterise flame and energy structure (e.g. individual cells, vertical heat profile and the height of well-mixing flaming gases), smoke structure (vertical distributions and multiple subplumes), ambient air processes (smoke eddy, entrainment and radiative effects of smoke aerosols) and fire emissions (for different fuel types and combustion conditions from flaming to residual smouldering), as well as night-time processes (smoke drainage and super-fog formation).
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Hagen, Bjarne C., e Anita K. Meyer. "From smoldering to flaming fire: Different modes of transition". Fire Safety Journal 121 (maggio 2021): 103292. http://dx.doi.org/10.1016/j.firesaf.2021.103292.
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Tu, Ran, Yi Zeng, Jun Fang e Yong-Ming Zhang. "Influence of high altitude on the burning behaviour of typical combustibles and the related responses of smoke detectors in compartments". Royal Society Open Science 5, n. 4 (aprile 2018): 180188. http://dx.doi.org/10.1098/rsos.180188.
Testo completoAbstract (sommario):
The effect of altitude on typical combustible burning and related smoke detector response signals was investigated by comparison experiments at altitudes of 40 m and 3650 m based on EN54 standard tests. Point-type light scattering photoelectric smoke detectors and ionization smoke detectors were used for four kinds of EN54 fire tests, including two kinds of smouldering fires with wood (test fire no. 2 in EN54 standard or TF2) and cotton (TF3), and two kinds of flaming fires with polyurethane (TF4) and n -heptane (TF5). First, the influence of altitude or ambient pressure on mass loss for smouldering combustion (TF2 or TF3) was insignificant, while a significant decrease in the mass burning rate was found for flaming tests (TF4 and TF5) as reported in our previous studies. Second, for photoelectric smoke detectors in flaming fire tests, the effect of altitude was similar to that of the burning rate, whereas for the ionization smoke detectors, the response signal at high altitudes was shown to be ‘enhanced’ by the detection principle of the ionization chamber, leading to an even larger value than at normal altitude for smouldering conditions. Third, to provide a reference for smoke detector design in high-altitude areas, the differences between signal speed in rising and peak values at two locations are discussed. Also, relationship between ion chamber signals and smoke optical densities are presented by utilization of an ionization smoke detector and smoke concentration meter. Moreover, a hierarchical diagram is illustrated to provide a better understanding of the effects of altitude on combustible burning behaviour and the mechanisms of detector response.
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Lu, Chang, Die Meng e Ming Gao Yu. "Study on Material Parameters Effects on Smoldering and Transition from Smoldering to Flaming Combustion". Advanced Materials Research 261-263 (maggio 2011): 571–75. http://dx.doi.org/10.4028/www.scientific.net/amr.261-263.571.
Testo completoAbstract (sommario):
The polyurethane foam is a most common fuel in smoldering fire. A small scale experimental compartment was built. The width, thickness and density of polyurethane foam material were changed several times in the experiments. Temperature histories measurement and analysis gaseous were used to explore the transition’s mechanism. The results show that with the width increased, the surface area and the air flow rate which access to the inside of material have also increased, and the quantity of oxygen is sufficient, heat release quantity by carbon oxidation is increased. When the width reaches a certain value, polyurethane foam material transformed easier from smoldering to flaming combustion. The polyurethane foam transforms to the flaming combustion not only depends on the length, width size but also relates to the thickness closely. When thickness reached a certain size, the temperature also reaches a whole jump. And the material transforms to the flaming combustion finally. The oxidation of larger density polyurethane foam material produces more heat, and then accumulates heat in the polyurethane foam center to reach the required temperature of gas phase reaction and ultimately transforms to flaming combustion from smoldering.
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Benrashid, R., G. L. Nelson e Donald J. Ferm. "Effect of Zinc and Zinc Borate on Fire Properties of Modified Polyphenylene Oxide". Journal of Fire Sciences 11, n. 3 (maggio 1993): 210–31. http://dx.doi.org/10.1177/073490419301100302.
Testo completoAbstract (sommario):
Modified polyphenylene oxide resin (m-PPO) (virgin) and m-PPO flame retarded with triaryl phosphate (FR m-PPO) were blended with zinc borate, zinc, and zinc/zinc borate. Both virgin and FR m-PPO containing zinc borate showed a marked reduction in smoke production (flaming and non- flaming-NBS Smoke Chamber). In FR m-PPO a reduction in oxygen index values was seen for zinc borate, except at the highest level tested (50 PHR). Zinc, on the other hand, showed an increase in oxygen index for FR m-PPO. Given the potential for both condensed and vapor phase activity for triaryl phosphate in m-PPO, the reduction in both smoke and oxygen index by zinc borate suggests a deactivation of the vapor phase activity of triaryl phosphate.
26
Porowski, Rafał, Robert Kowalik, Piotr Ramiączek, Paulina Bąk-Patyna, Paweł Stępień, Maria Zielecka, Tomasz Popielarczyk, Agata Ludynia, Angelika Chyb e Jarosław Gawdzik. "Application Assessment of Electrical Cables during Smoldering and Flaming Combustion". Applied Sciences 13, n. 6 (15 marzo 2023): 3766. http://dx.doi.org/10.3390/app13063766.
Testo completoAbstract (sommario):
Electrical cables are a potential source of ignition and fire hazards in various types of buildings and industrial installations, as well as in all modes of transportation, including aircraft. Fires in buildings pose the greatest threat to human life and health. The composition of thermal degradation products depends mainly on the type of combustible materials and the type of combustion process—flaming or smoldering. The purpose of this paper was to determine, based on experimental studies, the effects of flaming and smoldering combustion on the response times of fire smoke detectors. In addition, the concentrations of fire gases formed in the process of duct combustion, including CO, SO2, NO2, NO, HCN, HCl, HBr and HF, were measured using an FTIR spectrometer. The results presented confirm the significant effect of the way the cable samples burned on detector tripping time. The highest concentration of smoke (Y) in the test chamber was obtained during flame combustion. It was further found that the characteristics of the cable insulation material used, such as the type of PVC, had a significant effect on the toxicity of the emitted gases. The largest amounts of toxic gases were emitted during the smoldering combustion of a cable with a plasticized PVC sheath.
27
Burrows, N. D. "Flame residence times and rates of weight loss of eucalypt forest fuel particles". International Journal of Wildland Fire 10, n. 2 (2001): 137. http://dx.doi.org/10.1071/wf01005.
Testo completoAbstract (sommario):
Shape, size, composition and arrangement of fuel particles within a fuel array significantly affect the way in which wildland fires behave. Australian eucalypt forest fire behaviour models characterise fine fuels according to the quantity burnt in the flaming zone, and the upper size limit for fine fuel particles is somewhat arbitrarily set at 6 mm for the McArthur Forest Fire Danger Meter and 10 mm for the Forest Fire Behaviour Tables for Western Australia. Flame residence time and rate of weight loss during combustion of dry eucalypt leaves and different dimensions of round wood were measured to provide a scientific basis for standardising litter fuel sampling in dry eucalypt forests. Eucalypt leaves burnt at a rate equivalent to a piece of 4 mm diameter round wood, with smaller diameter round wood being the most flammable component of the fuel array. Based on flame residence times of individual fuel particles measured in the laboratory, and eucalypt surface fuel arrays observed in the field, fine litter fuel sampling should be standardised to leaves and round wood less than 6 mm in diameter. This study also enables the determination of the contribution of larger fuel particles to flaming zone combustion and intensity.
28
Babrauskas, Vytenis. "Flammability of Upholstered Furniture with Flaming Sources". Cellular Polymers 8, n. 3 (maggio 1989): 198–224. http://dx.doi.org/10.1177/026248938900800303.
Testo completoAbstract (sommario):
A number of countries and localities have either recently adopted furniture flammability regulations, or are actively considering them. In addition, a number of furniture flammability test methods have been developed in recent years in the course of research. Some of the methods share certain similarities; but, even so, many different testing philosophies exist. It is the purpose of this paper to compare the more widely used of the methods and to examine their advantages and limitations. The impact of some recent research results on test method design is also considered. The methods are discussed only on their technical features and not on their regulatory aspects. The scope is limited to methods for testing the behaviour under flaming fire conditions, and excludes tests for determing the cigarette ignition resistance. Some unresolved areas where further research is desirable are also cited.
29
Sibulkin, Merwin, e Sant S. Tewari. "Measurements of flaming combustion of pure and fire-retarded cellulose". Combustion and Flame 59, n. 1 (gennaio 1985): 31–42. http://dx.doi.org/10.1016/0010-2180(85)90055-0.
Testo completo
30
Fisher, Daniel, Martin J. Wooster, Weidong Xu, Gareth Thomas e Puji Lestari. "Top-Down Estimation of Particulate Matter Emissions from Extreme Tropical Peatland Fires Using Geostationary Satellite Fire Radiative Power Observations". Sensors 20, n. 24 (10 dicembre 2020): 7075. http://dx.doi.org/10.3390/s20247075.
Testo completoAbstract (sommario):
Extreme fires in the peatlands of South East (SE) Asia are arguably the world’s greatest biomass burning events, resulting in some of the worst ambient air pollution ever recorded (PM10 > 3000 µg·m−3). The worst of these fires coincide with El Niño related droughts, and include huge areas of smouldering combustion that can persist for months. However, areas of flaming surface vegetation combustion atop peat are also seen, and we show that the largest of these latter fires appear to be the most radiant and intensely smoke-emitting areas of combustion present in such extreme fire episodes. Fire emissions inventories and early warning of the air quality impacts of landscape fire are increasingly based on the fire radiative power (FRP) approach to fire emissions estimation, including for these SE Asia peatland fires. “Top-down” methods estimate total particulate matter emissions directly from FRP observations using so-called “smoke emission coefficients” [Ce; g·MJ−1], but currently no discrimination is made between fire types during such calculations. We show that for a subset of some of the most thermally radiant peatland fires seen during the 2015 El Niño, the most appropriate Ce is around a factor of three lower than currently assumed (~16.8 ± 1.6 g·MJ−1 vs. 52.4 g·MJ−1). Analysis indicates that this difference stems from these highly radiant fires containing areas of substantial flaming combustion, which changes the amount of particulate matter emitted per unit of observable fire radiative heat release in comparison to more smouldering dominated events. We also show that even a single one of these most radiant fires is responsible for almost 10% of the overall particulate matter released during the 2015 fire event, highlighting the importance of this fire type to overall emission totals. Discriminating these different fires types in ways demonstrated herein should thus ultimately improve the accuracy of SE Asian fire emissions estimates derived using the FRP approach, and the air quality modelling which they support.
31
Kaaret, Philip, Steve Tammes, Jun Wang, Thomas Schnell, Marc Linderman, Carlton H. Richey, Colin M. Packard, Meng Zhou e Chase A. Fuller. "On the Potential of Flaming Hotspot Detection at Night via Multiband Visible/Near-Infrared Imaging". Remote Sensing 14, n. 19 (9 ottobre 2022): 5019. http://dx.doi.org/10.3390/rs14195019.
Testo completoAbstract (sommario):
The severity of wildfires is increasing and has driven increases in nighttime fire activity. Enhanced capability to detect the active burning regions of wildfires at night could significantly improve the effectiveness of wildfire management operations. Potassium line emission in the NIR near 770 nm is a signature of active burning. We test the use of multi-band imaging from an aircraft at night to distinguish a wood-burning fire from artificial light sources. We find that a simple ratio of the signals in two broad bands, one including 770 nm, effectively discriminates the fire from artificial light sources. This offers the possibility of nighttime fire detection with high spatial resolution using silicon sensors sensitive in the NIR.
32
Choi, Su-Gil, Yoo-Jeong Choi, Yeong-Jae Nam e Si-Kuk Kim. "Fire Detection Tendency through Combustion Products Generated during UL 268 Wood Flame Fire and Smoldering Fire Test". Fire Science and Engineering 35, n. 1 (28 febbraio 2021): 48–57. http://dx.doi.org/10.7731/kifse.23b37311.
Testo completoAbstract (sommario):
This experiment analyzes the tendency of fire detection through combustion products generated during UL 268 wood flame fires and smoldering tests. Fire detection tendency was measured using a particle matter sencor (PMS), combustion gas analyzer (CGA), and gas analyzer (GA). The combustion products were matched and analyzed at 5 %/m (non-operation), 10 %/m, and 15 %/m of the smoke sensitivity measured by the smoke detector. In the case of wood flaming fire, PMS PM 10, CGA CO, SO2, GA HCHO, and TVOC, the trend was observed because of the continuous increase in the measured value according to the smoke generation. In the case of smoldering, PM 10, CO, and HCHO were adaptable to the tendency to be observed. Finally, in the case of wood fire accompanied by flame fire and smoldering to PM 10, CO and HCHO were considered to be the optimal fire detection factors.
33
Viegas, Domingos Xavier, e Luís Mário Ribeiro. "IX International Conference on Forest Fire Research and 17th International Wildland Fire Safety Summit: introduction to special issue (Part 1)". International Journal of Wildland Fire 32, n. 1 (24 gennaio 2023): 1–3. http://dx.doi.org/10.1071/wf23003.
Testo completoAbstract (sommario):
The ninth International Conference on Forest Fire Research (ICFFR) was recently held in Coimbra, Portugal, bringing together scientists and fire managers from around world to advance and update knowledge in the area of fire management. The conference was held jointly with the International Association of Wildland Fire’s 17th International Wildland Fire Safety Summit (IWFSS). Here we introduce Part 1 of a special issue series arising from the 2022 ICFFR/IWFFS joint meeting. This issue of the International Journal of Wildland Fire contains eight papers covering a wide variety of topics including: seasonal fire activity and spatio-temporal fire-weather patterns under climate change, the role of atmospheric conditions on fire and flaming zone behaviour, analytical techniques for measuring oxidative pyrolysis gases, particulate morphology of fires in the wildland–urban interface, deep peat fire smouldering and the impact of post-fire treatments on soil. All papers in the issue are published Open Access.
34
Johnston, D. C., M. R. Turetsky, B. W. Benscoter e B. M. Wotton. "Fuel load, structure, and potential fire behaviour in black spruce bogs". Canadian Journal of Forest Research 45, n. 7 (luglio 2015): 888–99. http://dx.doi.org/10.1139/cjfr-2014-0334.
Testo completoAbstract (sommario):
Boreal peatlands in Canada comprise a substantial store of soil organic carbon (peat), and this peat is vulnerable to extensive burning during periods of extended drying. Increased frequency of extreme weather events in boreal regions is expected with future climate change, and the conditions that would support sustained smouldering peat combustion within peatlands may be more common. Organic soils tend to burn by smouldering combustion, a very slow-moving process in fuels such as those found in peatlands. Thus the most extreme conditions for carbon loss to the atmosphere due to the burning of peat likely occur when widespread propagation of flaming combustion leads to widespread initiation of smouldering. To investigate the potential for large-scale, high-intensity fire spread across forested bogs, we examined the fuel conditions in forested bogs necessary to support active crown fire. We measured surface and canopy fine fuels (those available to contribute to the propagating energy flux of the main flaming front) across a postfire chronosequence of forested boreal bog from central Alberta, Canada. We found that fuel load of fine surface material remained relatively constant across the chronosequence and at levels large enough to support crown fire initiation. Black spruce (Picea mariana (Mill.) B.S.P.) regeneration begins to fill in the crown space with increasing time since disturbance and achieves crown bulk densities similar to black spruce upland forests. We estimated that after about 80 years, the black spruce canopy has developed enough available fuel to support active crown fire on between 10% to 40% of days in a typical fire season in central Alberta, Canada. Broad-scale propagation of high-intensity fire across a peatland when coincident with drought-induced lower moisture in deep peatland layers has the potential to lead to a substantial release of stored terrestrial carbon.
35
Putzeys, Olivier M., A. Carlos Fernandez-Pello, Guillermo Rein e David L. Urban. "The piloted transition to flaming in smoldering fire retarded and non-fire retarded polyurethane foam". Fire and Materials 32, n. 8 (dicembre 2008): 485–99. http://dx.doi.org/10.1002/fam.981.
Testo completo
36
Lingam, Revathy Amadera, e Norizah Aripin. "Comments on Fire! Classifying Flaming Comments on YouTube Videos in Malaysia". Jurnal Komunikasi, Malaysian Journal of Communication 33, n. 4 (20 dicembre 2017): 104–18. http://dx.doi.org/10.17576/jkmjc-2017-3304-07.
Testo completo
37
Thonat, T., C. Crevoisier, N. A. Scott, A. Chédin, R. Armante e L. Crépeau. "Signature of tropical fires in the diurnal cycle of tropospheric CO as seen from Metop-A/IASI". Atmospheric Chemistry and Physics Discussions 14, n. 19 (17 ottobre 2014): 26003–39. http://dx.doi.org/10.5194/acpd-14-26003-2014.
Testo completoAbstract (sommario):
Abstract. Five years (July 2007–June 2012) of CO tropospheric columns derived from the IASI hyperspectral infrared sounder onboard Metop-A are used to study the impact of fires on the concentrations of CO in the mid-troposphere. Following Chédin et al. (2005, 2008), who showed the existence of a daily tropospheric excess of CO2 quantitatively related to fire emissions, we show that tropospheric CO also displays a diurnal signal with a seasonality that is in very good agreement with the seasonal evolution of fires given by GFED3.1 (Global Fire Emission Database) emissions and MODIS (Moderate Resolution Imaging Spectroradiometer) burned area. Unlike daytime or nighttime CO fields, which mix local emissions with nearby emissions transported to the region of study, the day-night difference of CO allows to highlight the CO signal due to local fire emissions. A linear relationship is found in the whole tropical region between CO fire emissions from the GFED3.1 inventory and the diurnal difference of IASI CO (R2 ~ 0.6). Based on the specificity of the two main phases of the combustion (flaming vs. smoldering) and on the vertical sensitivity of the sounder to CO, the following mechanism is proposed to explain such a CO diurnal signal: at night, after the passing of IASI at 9.30 p.m. LT, a large amount of CO emissions from the smoldering phase is trapped in the boundary layer before being uplifted the next morning by natural and pyro-convection up to the free troposphere, where it is seen by IASI at 9.30 a.m. LT. The results presented here highlight the need for developing complementary approaches to bottom-up emissions inventories and for taking into account the specificity of both the flaming and smoldering phases of fire emissions in order to fully take advantage of CO observations.
38
Almeida, Miguel, Domingos Xavier Viegas, Ana Isabel Miranda e Valeria Reva. "Effect of particle orientation and of flow velocity on the combustibility of Pinus pinaster and Eucalyptus globulus firebrand material". International Journal of Wildland Fire 20, n. 8 (2011): 946. http://dx.doi.org/10.1071/wf09080.
Testo completoAbstract (sommario):
Spotting is a very important mechanism of forest fire spread. Its negative effect increases in extreme fire danger conditions. In order to predict the maximum spotting distance, the duration of the combustion reaction of potential firebrands should be evaluated. This paper reports the results of an experimental laboratory study of the combustibility of firebrand material (pine cones and scales and pieces of bark of eucalypt) of two representative species in Portugal, Pinus pinaster Ait. and Eucalyptus globulus Labill. The main purpose was to assess the role on the burning conditions of the firebrand particle orientation angle θ in relation to the airflow and of the flow velocity (U) around the particle. Tests were made varying the angle of orientation of the main axis of the particle in relation to incident flow in the range of ±90°; flow velocities were tested from 0 to 6.5 m s–1. After ignition, particle mass loss owing to flaming or glowing combustion of the particle was continuously measured. Residual mass, duration of the flaming phase and the burnout times are reported for each case. Empirical models to estimate the trends of variation of some of these parameters with θ and U are proposed to illustrate their importance for the range of test conditions.
39
Kremens, Robert L., e Matthew B. Dickinson. "Estimating radiated flux density from wildland fires using the raw output of limited bandpass detectors". International Journal of Wildland Fire 24, n. 4 (2015): 461. http://dx.doi.org/10.1071/wf14036.
Testo completoAbstract (sommario):
We have simulated the radiant emission spectra from wildland fires such as would be observed at a scale encompassing the pre-frontal fuel bed, the flaming front and the zone of post-frontal combustion and cooling. For these simulations, we developed a ‘mixed-pixel’ model where the fire infrared spectrum is estimated as the linear superposition of spectra of many (n ~ 30) greybody emitters of randomly selected areal fraction, emissivity and temperature. Our model neglects contributions from atomic and molecular line emission from combustion gasses. The purpose of these simulations was to allow unambiguous use of limited bandwidth detectors to estimate the total power emitted from a wildland fire. From the simulations we observed a well-defined relationship between ground-leaving radiance (W m–2 sr–1) and limited bandpass sensor-reaching radiance for many different detector spectral responses. Error in the relationship is least when the detector sampled in the mid-wave portion of the infrared spectrum (~3–5 μm) where flaming combustion emits most strongly. We validate our approach to estimating total power using data from experimental burns. The ability to estimate total power from limited bandpass measurements has great utility in the observation of wildland fires from ground-based instruments and aircraft and satellite platforms.
40
Dupuy, Jean-Luc, e Michel Larini. "Fire spread through a porous forest fuel bed: a radiative and convective model including fire-induced flow effects". International Journal of Wildland Fire 9, n. 3 (1999): 155. http://dx.doi.org/10.1071/wf00006.
Testo completoAbstract (sommario):
A simplified physical model for the steady-state propagation of an infinite fire front through a uniform forest fuel bed in still air is derived from a mechanistic approach that considers a forest fire as a compressible, reactive and radiative flow through a multiphase medium. This model, named the PIF97 model for shortness, includes the effects of the buoyancy induced gas flow on the preheating of the unburned fuel. Fuel is composed of one type of motionless particles uniformly distributed in a fuel bed of constant depth. The conservation equations used in the model are integrated over the fuel bed depth. The spatial domain is divided into the preheating zone ahead of the fire front and the flaming combustion zone. In the preheating zone (model A), pyrolysis and chemical reactions are neglected, and the gas flow is assumed to be one-dimensional. In the flaming combustion zone (model B), some average parameters over this zone are given in order to simplify the description of physical and chemical processes. Models A and B are coupled to form the PIF97 model. The predictions of this model are compared with experimental rates of spread measured during laboratory fire experiments in pine needle fuel beds. That shows the accomplished progress by comparison to the predictions of a purely radiative model and also the limits of the PIF97 model. Under the present experimental conditions, this model correctly predicts the effect of surface-to-volume ratio, and may predict the effect of fuel load, but the quantitative effect of slope is clearly underestimated. Possible reasons for the remaining discrepancies between predictions and experimental results are investigated through an analysis of separate predictions of model A and model B.
41
Cohen, Jack D. "Relating flame radiation to home ignition using modeling and experimental crown fires". Canadian Journal of Forest Research 34, n. 8 (1 agosto 2004): 1616–26. http://dx.doi.org/10.1139/x04-049.
Testo completoAbstract (sommario):
Wildlandurban fire destruction depends on homes igniting and thus requires an examination of the ignition requirements. A physicaltheoretical model, based on severe case conditions and ideal heat transfer characteristics, estimated wood wall ignition occurrence from flame radiation heating and piloted ignition requirements. Crown fire experiments provided an opportunity for assessing model reliability. The crown fire experiments were specifically instrumented with wood wall sections and heat flux sensors to investigate direct flame heating leading to home ignition during wildland fires. The experimental results indicated that the flame radiation model overestimated the structure-to-flame distance that would result in wood wall ignition. Wall sections that ignited during the experimental crown fires did not sustain flaming after crown fire burnout. The experiments also revealed that the forest canopy attenuated the flame radiation as the crown fire spread within the forest plot. Ignition modeling and the associated crown fire experiments described the flame-to-structure distance scale associated with flame heating related to wall ignition.
42
Wang, Lian Tie, Da Wei Xia, Ao Gao e Qing Shan Meng. "The Discussion of Iron Wire Fire Hazard". Advanced Materials Research 535-537 (giugno 2012): 1847–50. http://dx.doi.org/10.4028/www.scientific.net/amr.535-537.1847.
Testo completoAbstract (sommario):
The safe current carrying capacity of iron wire is far less than copper wires. In the simulation experiments, use iron wire replace copper wire and use welding machine as electric equipment, even the flaming. Normal operating electric homework, the whole iron wire overheat and cause carbonization of insulation layer and even set on fire because of line’s overload, and lead to short circuit between wire. Extract fire material evidence, observe and analysis. Summed up the microstructure characteristics of the sample. Apparent characteristics of short circuit melting mark organization is:wire matrix is widmanstatten structure and ferrite, the transition region is mainly widmanstatten structure; overload melted mark organization is mainly cast structure, there was more casting .
43
Chase, Carlene A., Rosalie L. Koenig, Jeffery E. Pack e Clinton C. Warren. "PURPLE NUTSEDGE MANAGEMENT FOR ORGANIC VEGETABLE PRODUCTION". HortScience 41, n. 3 (giugno 2006): 505A—505. http://dx.doi.org/10.21273/hortsci.41.3.505a.
Testo completoAbstract (sommario):
Weed management is a major constraint of organic vegetable production and perennial weeds such as purple nutsedge (Cyperus rotundus) are particularly difficult to control. A study was initiated in 2005 to determine how summer fallow techniques impact purple nutsedge population density, tuber number and tuber viability; and to evaluate the impact of the treatments on the yields of two fall crops differing in canopy size and rate of development. Clean fallow treatments accomplished with weekly tillage or weekly flaming were conducted for 12 weeks. Two sets of summer cover crop treatments of sunn hemp (Crotalaria juncea) were established by broadcasting 40 lb of seed per acre and were undercut at 13 weeks after seeding. Cover crop residue was either incorporated before transplanting or retained on the surface as mulch for the fall crops of lettuce and broccoli. Soil solarization was initiated on 2 July and the transparent solarization film was maintained in place until mid-October. A weedy fallow treatment was included as a control, which was tilled before establishing the fall crops. Before the initiation of the summer fallow treatments, no difference in viable tubers or nutsedge shoot density was observed. After fallow, flaming had the highest number of viable tubers, with all other treatments similar to the weedy control. Nutsedge shoot density was suppressed by all fallow treatments to lower levels than with the weedy control, but solarization was the least effective. Leaf-cutting insects eliminated the crops in the sunn hemp mulch treatment within days of being transplanted. Lettuce stands with all other treatments were similar and greater than with the weedy control. Highest broccoli stands were obtained with flaming, solarization, and tillage; but broccoli stand with incorporated sunn hemp was similar to the weedy control. Highest lettuce yields occurred with incorporated sunn hemp, solarization, and weekly tillage. However, lettuce yields with flaming and the weedy control did not differ statistically. Broccoli yields were greatest with flaming, solarization, and tillage. Broccoli development was delayed with the weedy control and incorporated sunn hemp treatments and no significant yield was obtained.
44
Thonat, T., C. Crevoisier, N. A. Scott, A. Chédin, R. Armante e L. Crépeau. "Signature of tropical fires in the diurnal cycle of tropospheric CO as seen from Metop-A/IASI". Atmospheric Chemistry and Physics 15, n. 22 (25 novembre 2015): 13041–57. http://dx.doi.org/10.5194/acp-15-13041-2015.
Testo completoAbstract (sommario):
Abstract. Five years (July 2007 to June 2012) of CO tropospheric columns derived from the hyperspectral Infrared Atmospheric Sounding Interferometer (IASI) on-board Metop-A are used to study the impact of fires on the concentrations of CO in the troposphere. Following Chédin et al. (2005, 2008), who found a quantitative relation between the daily tropospheric excess of CO2 and fire emissions, we show that tropospheric CO also displays a diurnal signal with a seasonality that agrees well with the seasonal evolution of fires given by Global Fire Emission Database version 3 (GFED3.1) and Global Fire Assimilation System version 1 (GFAS1.0) emissions and Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 5 burned area product. Unlike day- or night-time CO fields, which mix local emissions with nearby emissions transported to the region of study, the day–night difference of CO allows to highlight the CO signal due to local fire emissions. A linear relationship between CO fire emissions from the GFED3.1 and GFAS1.0 inventories and the diurnal difference of IASI CO was found over various regions in the tropics, with a better agreement with GFAS1.0 (correlation coefficient of R2 ∼ 0.7) than GFED3.1 (R2 ∼ 0.6). Based on the specificity of the two main phases of the combustion (flaming vs. smoldering) and on the vertical sensitivity of the sounder to CO, the following mechanism is proposed to explain such a CO diurnal signal: at night, after the passing of IASI at 21:30 local time (LT), a large amount of CO emissions from the smoldering phase is trapped in the boundary layer before being uplifted the next morning by natural and pyroconvection up to the free troposphere, where it is seen by IASI at 09:30 LT. The results presented here highlight the need to take into account the specificity of both the flaming and smoldering phases of fire emissions in order to fully take advantage of CO observations.
45
Clements, Craig B. "Thermodynamic structure of a grass fire plume". International Journal of Wildland Fire 19, n. 7 (2010): 895. http://dx.doi.org/10.1071/wf09009.
Testo completoAbstract (sommario):
High-frequency thermocouple measurements were made during an experimental grass fire conducted during ideal weather with overcast and windy conditions. Analysis of the thermodynamic structure of the fire plume showed that a maximum plume temperature of 295.2°C was measured directly above the combustion zone. Plume heating rates were on the order of 26–45 kW m–2 and occurred in the region just above the combustion zone between 10 and 15 m above ground level and were followed by cooling of approximately –37 and –44 kW m–2. The observed cooling was caused by strong entrainment that occurred behind the fire front and plume. The rapid heating and subsequent cooling indicate that the heating caused by a fire front is limited to a small volume around the flaming front and that the rates of heat gain occur for a short duration. The short duration of plume heating is due to the fast rate of spread of the fire front and ambient wind.
46
Hosseini, S., L. Qi, D. Cocker, D. Weise, A. Miller, M. Shrivastava, W. Miller, S. Mahalingam, M. Princevac e H. Jung. "Particle size distributions from laboratory-scale biomass fires using fast response instruments". Atmospheric Chemistry and Physics Discussions 10, n. 4 (6 aprile 2010): 8595–621. http://dx.doi.org/10.5194/acpd-10-8595-2010.
Testo completoAbstract (sommario):
Abstract. Particle size distribution from biomass combustion is an important parameter as it affects air quality, climate modelling and health effects. To date particle size distributions reported from prior studies vary not only due to difference in fuels but also difference in experimental conditions. This study aims to report characteristics of particle size distribution in a well controlled repeatable lab scale biomass fires for southwestern US fuels. The combustion facility at the USDA Forest Service's Fire Science Laboratory (FSL), Missoula, MT provided repeatable combustion and dilution environment ideal for particle size distribution study. For a variety of fuels tested the major mode of particle size distribution was in the range of 29 to 52 nm, which was attributable to dilution of the fresh smoke. Comparing volume size distribution from Fast Mobility Particle Sizer (FMPS) and Aerodynamic Particle Sizer (APS) measurements, ~30% of particle volume was attributable to the particles ranging from 0.5 to 10 μm for PM10. Geometric mean diameter rapidly increased during flaming and gradually decreased during mixed and smoldering phase combustion. Most of fuels gave unimodal distribution during flaming phase and strong biomodal distribution during smoldering phase. The mode of combustion (flaming, mixed and smoldering) could be better distinguished using slopes in Modified Combustion Efficiency (MCE) vs. geometric mean diameter from each mode of combustion than only using MCE values.
47
Hosseini, S., Q. Li, D. Cocker, D. Weise, A. Miller, M. Shrivastava, J. W. Miller, S. Mahalingam, M. Princevac e H. Jung. "Particle size distributions from laboratory-scale biomass fires using fast response instruments". Atmospheric Chemistry and Physics 10, n. 16 (30 agosto 2010): 8065–76. http://dx.doi.org/10.5194/acp-10-8065-2010.
Testo completoAbstract (sommario):
Abstract. Particle size distribution from biomass combustion is an important parameter as it affects air quality, climate modelling and health effects. To date, particle size distributions reported from prior studies vary not only due to difference in fuels but also difference in experimental conditions. This study aims to report characteristics of particle size distributions in well controlled repeatable lab scale biomass fires for southwestern United States fuels with focus on chaparral. The combustion laboratory at the United States Department of Agriculture-Forest Service's Fire Science Laboratory (USDA-FSL), Missoula, MT provided a repeatable combustion and dilution environment ideal for measurements. For a variety of fuels tested the major mode of particle size distribution was in the range of 29 to 52 nm, which is attributable to dilution of the fresh smoke. Comparing mass size distribution from FMPS and APS measurement 51–68% of particle mass was attributable to the particles ranging from 0.5 to 10 μm for PM10. Geometric mean diameter rapidly increased during flaming and gradually decreased during mixed and smoldering phase combustion. Most fuels produced a unimodal distribution during flaming phase and strong biomodal distribution during smoldering phase. The mode of combustion (flaming, mixed and smoldering) could be better distinguished using the slopes in MCE (Modified Combustion Efficiency) vs. geometric mean diameter than only using MCE values.
48
Hartford, RA, e WH Frandsen. "When It's Hot, It's Hot... Or Maybe It's Not! (Surface Flaming May Not Portend Extensive Soil Heating)". International Journal of Wildland Fire 2, n. 3 (1992): 139. http://dx.doi.org/10.1071/wf9920139.
Testo completoAbstract (sommario):
Fire effects on aplant community, soil, and air are not apparent when judged only by surface fire intensity. The fire severity or fire impact can be described by the temperatures reached within the forest floor and the duration of heating experienced in the vegetation, forest floor, and underlying mineral soil. Temporal distributions of temperatures illustrate heat flow in duff and mineral soil in three instrumented plots: two with slash fuel over moist duff and one with litter fuel over dry duff. Fires in the two slash fuel plots produced substantial flame lengths but minimal heating in the underlying mineral soil. In contrast, smoldering combustion in the dry duff plot produced long duration heating with nearly complete duff consumption and lethal temperatures at the mineral soil surface. Moisture content of duff and soil were key variables for determining f i e impact on the forest floor.
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Elvidge, Christopher D., Mikhail Zhizhin, Feng Chi Hsu, Tamara Sparks e Tilottama Ghosh. "Subpixel Analysis of Primary and Secondary Infrared Emitters with Nighttime VIIRS Data". Fire 4, n. 4 (7 novembre 2021): 83. http://dx.doi.org/10.3390/fire4040083.
Testo completoAbstract (sommario):
Biomass burning is a coupled exothermic/endothermic system that transfers carbon in several forms to the atmosphere, ultimately leaving mineral ash. The exothermic phases include flaming and smoldering, which produce the heat that drives the endothermic processes. The endothermic components include pre-heating and pyrolysis, which produce the fuel consumed by flaming and smoldering. These components can be broadly distinguished from each other based on temperature. For several years, we have researched the subpixel analysis of two temperature phases present in fire pixels detected in nighttime VIIRS data. Here, we present the flaming subtractive method, with which we have successfully derived temperatures and source areas for two infrared (IR) emitters and a cooler background. This is developed as an add-on to the existing VIIRS nightfire algorithm version 3 (VNF v.3) which uses Planck curve fitting to calculate temperatures and source areas for a single IR emitter and background. The flaming subtractive method works with data collected in four spectral ranges: near-infrared (NIR), short-wave infrared (SWIR), mid-wave infrared (MWIR) and long-wave infrared (LWIR). With sunlight eliminated, the NIR and SWIR radiances can be fully attributed to the primary IR emitter. The analysis begins with Planck curve modeling for the primary emitter based on the NIR and SWIR radiances, yielding temperature, source area and primary emitter radiances in all spectral bands. The primary emitter radiances are subtracted from each spectral band and then the residual radiance is analyzed for a secondary IR emitter and the background. Spurious results are obtained in pixels lacking a discernable secondary emitter. These misfit pixels revert back to the single IR emitter analysis of VNF v.3. In tests run for two California megafires, we found that the primary emitters straddle the temperature ranges for flaming and smoldering, the exothermic portions of biomass burning, which are apparently commingled on the ground. The secondary emitter temperatures span 350–750 K, corresponding to pre-heating and slow pyrolysis. The natural gas flare test case had few numbers of successful secondary emitter retrievals and a wide range of secondary emitter temperatures. The flaming subtractive analysis is the key addition to VNF version 4, which will commence production later in 2021. In 2022, we will seek validation of the VNF v.4 from nighttime Landsat and other data sources.
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Kim, Sung-Chan, e Dong-Gun Nam. "Fire Characteristics of Flaming and Smoldering Combustion of Wood Combustibles Considering Thickness". Fire Science and Engineering 29, n. 4 (31 agosto 2015): 67–72. http://dx.doi.org/10.7731/kifse.2015.29.4.067.
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