This paper discusses a method for performing a sensitivity analysis of parameters used in a simplified fire model for temperature estimates in the upper smoke layer during a fire. The results from the sensitivity anal...This paper discusses a method for performing a sensitivity analysis of parameters used in a simplified fire model for temperature estimates in the upper smoke layer during a fire. The results from the sensitivity analysis can be used when individual parameters affecting fire safety are assessed. If the variation of a single parameter is found to have a major impact on fire safety, it may be necessary to conservatively select this parameter in order to incorporate additional safety. We compare fire scenarios in rooms surrounded by lightweight as well as heavy walls in order to investigate which parameters are the most significant in each case. We apply the Sobol method, which is a quantitative method that gives the percentage of the total output variance that each parameter accounts for. The most important parameter is found to be the energy release rate that explains 92% of the uncertainty in the calculated results for the period before thermal penetration （te） has occurred. The analysis is also done for all combinations of two parameters in order to find the combination with the largest effect. The Sobol total for pairs had the highest value for the combination of energy release rate and area of opening, which explains 96% of the uncertainty. After thermal penetration, the energy release rate is still the most important parameter, but now only explains 49% of the variation. The second parameter is the thickness of the surface material, which explains 43%.展开更多
The risk of forest fires is substantial due to uneven precipitation distributions and abnormal climate change.This study employs cellular automata principles to analyze forest fire behavior,taking into account meteoro...The risk of forest fires is substantial due to uneven precipitation distributions and abnormal climate change.This study employs cellular automata principles to analyze forest fire behavior,taking into account meteorological elements,combustible material types,and terrain slopes.The Wang Zhengfei model is utilized to compute fire spread speed,and a multifactor coupled forest fire model is developed.Comparisons with experimental data show a mean calculated fire spread speed of 0.69 m/min,which is consistent with the experimental results.Using the forest fire in Anning city,Yunnan Province,as a case study with a mean burned area of 2281 ha,the burned area,rate of change in burned area,and burning area demonstrated an increasing trend,with fluctuating states in the rate of change of the burning area.Employing the controlled variable method to examine forest fire spreading patterns under varying factors such as wind speed,vegetation type,and maximum slope reveals that under wind influence,the fire site adopts an elliptical shape with the downwind direction as the major axis.Quantitatively,when the wind speed increases from 2 m/s to 10 m/s,the burned area expands by a factor of 1.37.The ratio of the combustible material configuration coefficient to the burned area remains consistent across the different vegetation types,and the burned area increases by a factor of 1.92 when the maximum slope increases from 5°to 25°.展开更多
The influences of finite-size effects on the self-organized criticality (SOC) of the traditional forest-fire model are investigated by means of a new method. The forest size is originally set to a value much greater t...The influences of finite-size effects on the self-organized criticality (SOC) of the traditional forest-fire model are investigated by means of a new method. The forest size is originally set to a value much greater than the correla-tion length of the forest. Finite-size effects are then studied by equally dividing the forest into more and more separate subsystems on condition that the forest size, igniting prob-ability and planting probability are invariant. A new phe-nomenon, i.e. the finite-size effects with one-side frequency peak, is observed. The boundary between two neighboring subsystems can be regarded as a firebreak. The concept of ’separation ability’ is introduced to represent the probability for the firebreak to block off the fire successfully. Restrain-ing effects of separation ability on finite-size effects are ana-lyzed. Finite-size effects and separation ability, as well as their relations are found to have practical importance to the actual forest-fire protection.展开更多
Recent fires in Iran’s Zagros forests have inflicted heavy,extensive losses to the environment,forests,villages,and forest inhabitants,resulting in a huge financial loss to the country.With the increasing risk of fir...Recent fires in Iran’s Zagros forests have inflicted heavy,extensive losses to the environment,forests,villages,and forest inhabitants,resulting in a huge financial loss to the country.With the increasing risk of fire and the resulting losses,it has become ever more necessary to design and develop efficient fire control and prediction procedures.The present study utilizes the Dong model to develop a map of areas vulnerable to fire in the Zarivar lake forests as a representative sample of Zagros forests.The model uses as its inputs some of the most significant factors(such as vegetation,physiographic features,and the human component)that affect the fire occurrence and spread.Having assigned weights to each factor based on the model,all maps were overlapped in the ArcMap and then the region was divided into five zones.The results showed that 74%of the region was located in three classes:highly vulnerable,vulnerable,and medially vulnerable.To validate the proposed zoning map it was compared with a map based on real data obtained from previous fires.The results showed that 81%of fire incidents were located in highly vulnerable,vulnerable and medially vulnerable zones.Furthermore,the findings indicated a medium to a high degree of fire vulnerability in Zarivar Lake forests.展开更多
Forest fire is one of the main natural hazards because of its fierce destructiveness. Various researches on fire real time monitoring, behavior simulation and loss assessment have been carried out in many countries. A...Forest fire is one of the main natural hazards because of its fierce destructiveness. Various researches on fire real time monitoring, behavior simulation and loss assessment have been carried out in many countries. As fire prevention is probably the most efficient means for protecting forests, suitable methods should be developed for estimating the fire danger. Fire danger is composed of ecological, human and climatic factors. Therefore, the systematic analysis of the factors including forest characteristics, meteorological status, topographic condition causing forest fire is made in this paper at first. The relationships between biophysical factors and fire danger are paid more attention to. Then the parameters derived from remote sensing data are used to estimate the fire danger variables, According to the analysis, not only PVI (Perpendicular Vegetation Index) can classify different vegetation but also crown density is captured with PVI. Vegetation moisture content has high correlation with the ratio of actual evapotranspiration (LE) to potential ecapotranspiration (LEp). SI (Structural Index), which is the combination of TM band 4 and 5 data, is a good indicator of forest age. Finally, a fire danger prediction model, in which relative importance of each fire factor is taken into account, is built based on GIS.展开更多
To apply the fire modelling for the fire engineer with symbolic mathematics,the key equations of a zone model were demonstrated. There were thirteen variables with nine constraints,so only four ordinary differential e...To apply the fire modelling for the fire engineer with symbolic mathematics,the key equations of a zone model were demonstrated. There were thirteen variables with nine constraints,so only four ordinary differential equations (ODEs) were required to solve. A typical fire modelling with two-room structure was studied. Accordingly,the source terms included in the ODEs were simplified and modelled,and the fourth Runge-Kutta method was used to solve the ordinary differential equations (ODEs) with symbolic mathematics. Then a zone model could be used with symbolic mathematics. It is proposed that symbolic mathematics is possible for use by fire engineer.展开更多
Risk management of forest fires starts from its assessment. This assessment has been subject of several research works and many models of fire risk have been developed. One of them has been developed by ourselves, for...Risk management of forest fires starts from its assessment. This assessment has been subject of several research works and many models of fire risk have been developed. One of them has been developed by ourselves, for the Mediterranean areas. However environmental vulnerability to forest fires is an important part of risk;it represents, in fact, the exposed challenge to this scourge and therefore it worths particular attention by decision makers. Thus and due to the importance of socio-economic potential of forest and the negative influence of fire on this one, we propose in this work, a model for vulnerability assessment to forest fires based on the principle of the weighted sum. Application of the proposed model suggested to use of geomatics technologies to the spatialize level of vulnerability. Within this framework, a GIS was developed and applied to the forests of Djelfa in the Saharian Atlas, as originality, it will allow the understanding of the concept of vulnerability and risk associated the steppes area scale to reach a good space control.展开更多
Mathematical model of forest fire was based on an analysis of known experimental data and using concept and methods from reactive media mechanics. In this paper the assignment and theoretical investigations of the pro...Mathematical model of forest fire was based on an analysis of known experimental data and using concept and methods from reactive media mechanics. In this paper the assignment and theoretical investigations of the problems of crown forest fire spread in windy condition were carried out. In this context, a study—mathematical modeling—of the conditions of forest fire spreading that would make it possible to obtain a detailed picture of the change in the temperature and component concentration fields with time, and determine as well as the limiting condition of fire propagation in forest with fire break.展开更多
The purpose of this study was to determine a suitable model for investigating the effects of climate factors on the area burned by forest fire in the Tahe forest region, Daxing＇an Mountains, in northeast China. The r...The purpose of this study was to determine a suitable model for investigating the effects of climate factors on the area burned by forest fire in the Tahe forest region, Daxing＇an Mountains, in northeast China. The response variables were the area burned by lightning- caused fire, human-caused fire, and total burned area. The predictor variables were nine climate variables collected from the local weather station. Three regression models were utilized, including multiple linear regression, log- linear model （log-transformation on both response and predictor variables）, and gamma-generalized linear model. The goodness-of-fit of the models were compared based on model fitting statistics such as R2, AIC, and RMSE. The results revealed that the gamma-generalized linear model was generally superior to both multiple linear regressionmodel and log-linear model for fitting the fire data. Further, the best models were selected based on the criteria that the climate variables were statistically significant at at = 0.05. The gamma best models indicated that maximum wind speed, precipitation, and days that rainfall greater than 0.1 mm had significant impacts on the area burned by the lightning-caused fire, while the mean temperature and minimum relative humidity were the .main drivers of the burned area caused by human activities. Overall, the total burned area by forest fire was significantly influenced by days that rainfall greater than 0.1 mm and minimum rela- tive humidity, indicating that the moisture condition of forest stands determine the burned area by forest fire.展开更多
Simulation of egress is vital for minimizing losses during fire disasters, however accurate simulations are scarce and real-life data is hard to come by. In this paper, a Proposed Wireless Fire Evacuation Model (PWFEM...Simulation of egress is vital for minimizing losses during fire disasters, however accurate simulations are scarce and real-life data is hard to come by. In this paper, a Proposed Wireless Fire Evacuation Model (PWFEM) is proposed to simulate fire evacuation process in a short time<span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">to minimize evacuee’s exposure to the harmful radiation and fire hazards. The PWFEM</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">simulation realistic by supposing fire scenario at</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">cabined contains electrical cables inside a standard Main Control Room (MCR) in a Nuclear Power Plant (NPP) building.</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">In addition, a</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">new Hybrid Safest Shortest Exit (HSSE) is developed</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">which consists of three stages: safest route based </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">o</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">n rules-based technique, evacuees location based on the DV-hop technique </span></span></span><span><span><span style="font-family:" color:#c45911;"=""><a href="#ref1" target="_blank"><span style="font-family:Verdana;">[1]</span></a></span><span></span></span></span><span><span></span></span><span></span><span><span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> and shortest route that depends on Dijkstra techniqu</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">e</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">. The PWFEM Simulations </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">are </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">appreciated</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">to yield a realistic fire scenario by using a telecommunications TCP/IP network in</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">form of server and client sides that help in transfer data inside internal networks in the NPP building. </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">O</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">n the server-side, suppose that</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">Consolidated Model of Fire Growth and Smoke Transport (CFAST) fire modeling is applied to simulate the fire scenario in MCR through CFAST model to generate fire products as output data in excel sheets and sends them to the client-side. The client-side then runs HSSE to produce the tree map for safest and shortest routes to help the evacuee for safe exit from his/her location.</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">HSSE can be implemented on evacuee’s watches. From the results, </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">it is </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">concluded that PWFEM can simulate the fire scenario inside MCR,</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">furthermore </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">it is </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">validated that HSEE can be used as an efficient emergency fire evacuation technique that can produce safest and shortest exit route for evacuee in any location inside NPP in very small time. In addition, PWFEM can be used for simulating</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">fire evacuation inside any high-risk buildings and can appreciate</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">yield</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ing</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> any realistic fire scenario with many types of fire sources in different places inside buildings.</span></span></span>展开更多
In this paper, we establish a mathematical model of the forest fire spread process based on a partial differential equation. We describe the distribution of time field and velocity field in the whole two-dimensional s...In this paper, we establish a mathematical model of the forest fire spread process based on a partial differential equation. We describe the distribution of time field and velocity field in the whole two-dimensional space by vector field theory. And we obtain a continuous algorithm to predict the dynamic behavior of forest fire spread in a short time. We use the algorithm to interpolate the fire boundary by cubic non-uniform rational B-spline closed curve. The fire boundary curve at any time can be simulated by solving the Eikonal equation. The model is tested in theory and in practice. The results show that the model has good accuracy and stability, and it’s compatible with most of the existing models, such as the elliptic model and the cellular automata model.展开更多
The management of the forest fire risk starts with it assessment. This assessment made the object of several works of research and many models of fire risk have been related. The model that interests us here is that e...The management of the forest fire risk starts with it assessment. This assessment made the object of several works of research and many models of fire risk have been related. The model that interests us here is that established for Mediterranean forests. This last is conceived according to a sum weighted model integral three factors, where each is affected by a weight, function of his influence on the propagation of the fire. However, this model remains critically and deserves a development and an improvement. For it, and seen the importance and the influence of climatic condition in the departure and in the propagation of fire, we propose, in this paper, to improve this formula by the addition of another climatic factor (marked ICL), and to present it under a product shape while respecting the same definition of the risk. The application of the proposed model, suggested uses the technical geomatics to mapping the degree of the fire risk. In this setting, a SIG has been established and applied on a forest of Bouzareah clump in Algiers. Originality as it will allow the understanding of fire hazard and vulnerability of the environment for a better control of risk.展开更多
Recent structural collapses caused by fire have focused attention on research concerning fire safety in building design. Steel connections are an important component of any structural steel building as they provide li...Recent structural collapses caused by fire have focused attention on research concerning fire safety in building design. Steel connections are an important component of any structural steel building as they provide links between the principal structural members. Considering the importance of this matter this paper describes a spring-stiffness model developed to predict the behavior of bolted angle connections bare-steel joints at elevated temperature. The joint components are considered as springs with predefined mechanical properties i.e. stiffness and strength. The elevated temperature joint’s response can be predicted by assem-bling the stiffness of the components which are assumed to degrade with increasing temperature based on the recommendations presented in the design parameters code. Comparison of the results from the model with existing experimental data showed good agreement. The proposed model can be easily modified to describe the elevated temperature behavior of other types of joint as well as joints under large rotations.展开更多
The blended-fuel based eddy-dissipation-concept combustion model was newly developed in the FireFOAM framework, and applied to simulate 30 cm×30 cm heptane-ethanol pool fire. Comparison was made of fire height, c...The blended-fuel based eddy-dissipation-concept combustion model was newly developed in the FireFOAM framework, and applied to simulate 30 cm×30 cm heptane-ethanol pool fire. Comparison was made of fire height, centerline temperature against experimental measurements, which shows that they match very well with each other. However, further studies are needed to examine the validation of this model in fire simulations with various scales.展开更多
Aiming at reducing the deficiency of the traditional fire pre-warning algorithms and the intelligent fire pre-warning algorithms such as artificial neural network,and then to improve the accuracy of fire prewarning fo...Aiming at reducing the deficiency of the traditional fire pre-warning algorithms and the intelligent fire pre-warning algorithms such as artificial neural network,and then to improve the accuracy of fire prewarning for high-rise buildings,a composite fire pre-warning controller is designed according to the characteristic（ nonlinear,less historical data,many influence factors）,also a high-rise building fire pre-warning model is set up based on the support vector regression（ SV R）. Then the wood fire standard history data is applied to make empirical analysis. The research results can provide a reliable decision support framework for high-rise building fire pre-warning.展开更多
文摘This paper discusses a method for performing a sensitivity analysis of parameters used in a simplified fire model for temperature estimates in the upper smoke layer during a fire. The results from the sensitivity analysis can be used when individual parameters affecting fire safety are assessed. If the variation of a single parameter is found to have a major impact on fire safety, it may be necessary to conservatively select this parameter in order to incorporate additional safety. We compare fire scenarios in rooms surrounded by lightweight as well as heavy walls in order to investigate which parameters are the most significant in each case. We apply the Sobol method, which is a quantitative method that gives the percentage of the total output variance that each parameter accounts for. The most important parameter is found to be the energy release rate that explains 92% of the uncertainty in the calculated results for the period before thermal penetration （te） has occurred. The analysis is also done for all combinations of two parameters in order to find the combination with the largest effect. The Sobol total for pairs had the highest value for the combination of energy release rate and area of opening, which explains 96% of the uncertainty. After thermal penetration, the energy release rate is still the most important parameter, but now only explains 49% of the variation. The second parameter is the thickness of the surface material, which explains 43%.
基金supported by the Major Scientific and Technological Projects of Yunnan Province: Research on Key Technologies of Ecological Environment Monitoring and Intelligent Management of Natural Resources in Yunnan (202202AD080010).
文摘The risk of forest fires is substantial due to uneven precipitation distributions and abnormal climate change.This study employs cellular automata principles to analyze forest fire behavior,taking into account meteorological elements,combustible material types,and terrain slopes.The Wang Zhengfei model is utilized to compute fire spread speed,and a multifactor coupled forest fire model is developed.Comparisons with experimental data show a mean calculated fire spread speed of 0.69 m/min,which is consistent with the experimental results.Using the forest fire in Anning city,Yunnan Province,as a case study with a mean burned area of 2281 ha,the burned area,rate of change in burned area,and burning area demonstrated an increasing trend,with fluctuating states in the rate of change of the burning area.Employing the controlled variable method to examine forest fire spreading patterns under varying factors such as wind speed,vegetation type,and maximum slope reveals that under wind influence,the fire site adopts an elliptical shape with the downwind direction as the major axis.Quantitatively,when the wind speed increases from 2 m/s to 10 m/s,the burned area expands by a factor of 1.37.The ratio of the combustible material configuration coefficient to the burned area remains consistent across the different vegetation types,and the burned area increases by a factor of 1.92 when the maximum slope increases from 5°to 25°.
基金This work was supported by the National Basic Research "973" Project in China the National Natural Science Foundation in China (Grant Nos. 59876039, 59936140 and 39970621).
文摘The influences of finite-size effects on the self-organized criticality (SOC) of the traditional forest-fire model are investigated by means of a new method. The forest size is originally set to a value much greater than the correla-tion length of the forest. Finite-size effects are then studied by equally dividing the forest into more and more separate subsystems on condition that the forest size, igniting prob-ability and planting probability are invariant. A new phe-nomenon, i.e. the finite-size effects with one-side frequency peak, is observed. The boundary between two neighboring subsystems can be regarded as a firebreak. The concept of ’separation ability’ is introduced to represent the probability for the firebreak to block off the fire successfully. Restrain-ing effects of separation ability on finite-size effects are ana-lyzed. Finite-size effects and separation ability, as well as their relations are found to have practical importance to the actual forest-fire protection.
文摘Recent fires in Iran’s Zagros forests have inflicted heavy,extensive losses to the environment,forests,villages,and forest inhabitants,resulting in a huge financial loss to the country.With the increasing risk of fire and the resulting losses,it has become ever more necessary to design and develop efficient fire control and prediction procedures.The present study utilizes the Dong model to develop a map of areas vulnerable to fire in the Zarivar lake forests as a representative sample of Zagros forests.The model uses as its inputs some of the most significant factors(such as vegetation,physiographic features,and the human component)that affect the fire occurrence and spread.Having assigned weights to each factor based on the model,all maps were overlapped in the ArcMap and then the region was divided into five zones.The results showed that 74%of the region was located in three classes:highly vulnerable,vulnerable,and medially vulnerable.To validate the proposed zoning map it was compared with a map based on real data obtained from previous fires.The results showed that 81%of fire incidents were located in highly vulnerable,vulnerable and medially vulnerable zones.Furthermore,the findings indicated a medium to a high degree of fire vulnerability in Zarivar Lake forests.
文摘Forest fire is one of the main natural hazards because of its fierce destructiveness. Various researches on fire real time monitoring, behavior simulation and loss assessment have been carried out in many countries. As fire prevention is probably the most efficient means for protecting forests, suitable methods should be developed for estimating the fire danger. Fire danger is composed of ecological, human and climatic factors. Therefore, the systematic analysis of the factors including forest characteristics, meteorological status, topographic condition causing forest fire is made in this paper at first. The relationships between biophysical factors and fire danger are paid more attention to. Then the parameters derived from remote sensing data are used to estimate the fire danger variables, According to the analysis, not only PVI (Perpendicular Vegetation Index) can classify different vegetation but also crown density is captured with PVI. Vegetation moisture content has high correlation with the ratio of actual evapotranspiration (LE) to potential ecapotranspiration (LEp). SI (Structural Index), which is the combination of TM band 4 and 5 data, is a good indicator of forest age. Finally, a fire danger prediction model, in which relative importance of each fire factor is taken into account, is built based on GIS.
基金Project(PolyU B-Q01e) supported by the Research Project "Onsetting of Internal Fire Whirls in Buildings and Associated Safet Provision"
文摘To apply the fire modelling for the fire engineer with symbolic mathematics,the key equations of a zone model were demonstrated. There were thirteen variables with nine constraints,so only four ordinary differential equations (ODEs) were required to solve. A typical fire modelling with two-room structure was studied. Accordingly,the source terms included in the ODEs were simplified and modelled,and the fourth Runge-Kutta method was used to solve the ordinary differential equations (ODEs) with symbolic mathematics. Then a zone model could be used with symbolic mathematics. It is proposed that symbolic mathematics is possible for use by fire engineer.
文摘Risk management of forest fires starts from its assessment. This assessment has been subject of several research works and many models of fire risk have been developed. One of them has been developed by ourselves, for the Mediterranean areas. However environmental vulnerability to forest fires is an important part of risk;it represents, in fact, the exposed challenge to this scourge and therefore it worths particular attention by decision makers. Thus and due to the importance of socio-economic potential of forest and the negative influence of fire on this one, we propose in this work, a model for vulnerability assessment to forest fires based on the principle of the weighted sum. Application of the proposed model suggested to use of geomatics technologies to the spatialize level of vulnerability. Within this framework, a GIS was developed and applied to the forests of Djelfa in the Saharian Atlas, as originality, it will allow the understanding of the concept of vulnerability and risk associated the steppes area scale to reach a good space control.
文摘Mathematical model of forest fire was based on an analysis of known experimental data and using concept and methods from reactive media mechanics. In this paper the assignment and theoretical investigations of the problems of crown forest fire spread in windy condition were carried out. In this context, a study—mathematical modeling—of the conditions of forest fire spreading that would make it possible to obtain a detailed picture of the change in the temperature and component concentration fields with time, and determine as well as the limiting condition of fire propagation in forest with fire break.
基金funded by Asia-Pacific Forests Net(APFNET/2010/FPF/001)National Natural Science Foundation of China(Grant No.31400552)Forestry industry research special funds for public welfare projects(201404402)
文摘The purpose of this study was to determine a suitable model for investigating the effects of climate factors on the area burned by forest fire in the Tahe forest region, Daxing＇an Mountains, in northeast China. The response variables were the area burned by lightning- caused fire, human-caused fire, and total burned area. The predictor variables were nine climate variables collected from the local weather station. Three regression models were utilized, including multiple linear regression, log- linear model （log-transformation on both response and predictor variables）, and gamma-generalized linear model. The goodness-of-fit of the models were compared based on model fitting statistics such as R2, AIC, and RMSE. The results revealed that the gamma-generalized linear model was generally superior to both multiple linear regressionmodel and log-linear model for fitting the fire data. Further, the best models were selected based on the criteria that the climate variables were statistically significant at at = 0.05. The gamma best models indicated that maximum wind speed, precipitation, and days that rainfall greater than 0.1 mm had significant impacts on the area burned by the lightning-caused fire, while the mean temperature and minimum relative humidity were the .main drivers of the burned area caused by human activities. Overall, the total burned area by forest fire was significantly influenced by days that rainfall greater than 0.1 mm and minimum rela- tive humidity, indicating that the moisture condition of forest stands determine the burned area by forest fire.
文摘Simulation of egress is vital for minimizing losses during fire disasters, however accurate simulations are scarce and real-life data is hard to come by. In this paper, a Proposed Wireless Fire Evacuation Model (PWFEM) is proposed to simulate fire evacuation process in a short time<span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">to minimize evacuee’s exposure to the harmful radiation and fire hazards. The PWFEM</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">simulation realistic by supposing fire scenario at</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">cabined contains electrical cables inside a standard Main Control Room (MCR) in a Nuclear Power Plant (NPP) building.</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">In addition, a</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">new Hybrid Safest Shortest Exit (HSSE) is developed</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">which consists of three stages: safest route based </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">o</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">n rules-based technique, evacuees location based on the DV-hop technique </span></span></span><span><span><span style="font-family:" color:#c45911;"=""><a href="#ref1" target="_blank"><span style="font-family:Verdana;">[1]</span></a></span><span></span></span></span><span><span></span></span><span></span><span><span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> and shortest route that depends on Dijkstra techniqu</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">e</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">. The PWFEM Simulations </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">are </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">appreciated</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">to yield a realistic fire scenario by using a telecommunications TCP/IP network in</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">form of server and client sides that help in transfer data inside internal networks in the NPP building. </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">O</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">n the server-side, suppose that</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">Consolidated Model of Fire Growth and Smoke Transport (CFAST) fire modeling is applied to simulate the fire scenario in MCR through CFAST model to generate fire products as output data in excel sheets and sends them to the client-side. The client-side then runs HSSE to produce the tree map for safest and shortest routes to help the evacuee for safe exit from his/her location.</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">HSSE can be implemented on evacuee’s watches. From the results, </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">it is </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">concluded that PWFEM can simulate the fire scenario inside MCR,</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">furthermore </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">it is </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">validated that HSEE can be used as an efficient emergency fire evacuation technique that can produce safest and shortest exit route for evacuee in any location inside NPP in very small time. In addition, PWFEM can be used for simulating</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">fire evacuation inside any high-risk buildings and can appreciate</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">yield</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ing</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> any realistic fire scenario with many types of fire sources in different places inside buildings.</span></span></span>
文摘In this paper, we establish a mathematical model of the forest fire spread process based on a partial differential equation. We describe the distribution of time field and velocity field in the whole two-dimensional space by vector field theory. And we obtain a continuous algorithm to predict the dynamic behavior of forest fire spread in a short time. We use the algorithm to interpolate the fire boundary by cubic non-uniform rational B-spline closed curve. The fire boundary curve at any time can be simulated by solving the Eikonal equation. The model is tested in theory and in practice. The results show that the model has good accuracy and stability, and it’s compatible with most of the existing models, such as the elliptic model and the cellular automata model.
文摘The management of the forest fire risk starts with it assessment. This assessment made the object of several works of research and many models of fire risk have been related. The model that interests us here is that established for Mediterranean forests. This last is conceived according to a sum weighted model integral three factors, where each is affected by a weight, function of his influence on the propagation of the fire. However, this model remains critically and deserves a development and an improvement. For it, and seen the importance and the influence of climatic condition in the departure and in the propagation of fire, we propose, in this paper, to improve this formula by the addition of another climatic factor (marked ICL), and to present it under a product shape while respecting the same definition of the risk. The application of the proposed model, suggested uses the technical geomatics to mapping the degree of the fire risk. In this setting, a SIG has been established and applied on a forest of Bouzareah clump in Algiers. Originality as it will allow the understanding of fire hazard and vulnerability of the environment for a better control of risk.
文摘Recent structural collapses caused by fire have focused attention on research concerning fire safety in building design. Steel connections are an important component of any structural steel building as they provide links between the principal structural members. Considering the importance of this matter this paper describes a spring-stiffness model developed to predict the behavior of bolted angle connections bare-steel joints at elevated temperature. The joint components are considered as springs with predefined mechanical properties i.e. stiffness and strength. The elevated temperature joint’s response can be predicted by assem-bling the stiffness of the components which are assumed to degrade with increasing temperature based on the recommendations presented in the design parameters code. Comparison of the results from the model with existing experimental data showed good agreement. The proposed model can be easily modified to describe the elevated temperature behavior of other types of joint as well as joints under large rotations.
基金supported by the National Basic Research Program of China(2012CB719704)EU IIFFP7 Project(909658)+1 种基金the National Natural Science Foundation of China(51276177)the Fundamental Research Funds for the Central Universities
文摘The blended-fuel based eddy-dissipation-concept combustion model was newly developed in the FireFOAM framework, and applied to simulate 30 cm×30 cm heptane-ethanol pool fire. Comparison was made of fire height, centerline temperature against experimental measurements, which shows that they match very well with each other. However, further studies are needed to examine the validation of this model in fire simulations with various scales.
基金Supported by the National Natural Science Foundation of China(11072035)
文摘Aiming at reducing the deficiency of the traditional fire pre-warning algorithms and the intelligent fire pre-warning algorithms such as artificial neural network,and then to improve the accuracy of fire prewarning for high-rise buildings,a composite fire pre-warning controller is designed according to the characteristic（ nonlinear,less historical data,many influence factors）,also a high-rise building fire pre-warning model is set up based on the support vector regression（ SV R）. Then the wood fire standard history data is applied to make empirical analysis. The research results can provide a reliable decision support framework for high-rise building fire pre-warning.
