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Sample records for analysis fire simulation

  1. Sensitivity Analysis of Fire Dynamics Simulation

    DEFF Research Database (Denmark)

    Brohus, Henrik; Nielsen, Peter V.; Petersen, Arnkell J.

    2007-01-01

    equations require solution of the issues of combustion and gas radiation to mention a few. This paper performs a sensitivity analysis of a fire dynamics simulation on a benchmark case where measurement results are available for comparison. The analysis is performed using the method of Elementary Effects......In case of fire dynamics simulation requirements to reliable results are most often very high due to the severe consequences of erroneous results. At the same time it is a well known fact that fire dynamics simulation constitutes rather complex physical phenomena which apart from flow and energy...

  2. Sensitivity analysis codes fire simulation; Analisis de sensibilidad en codigos de simulacion contra incendios

    Energy Technology Data Exchange (ETDEWEB)

    Cordero Garcia, S.; Peco Espinosa, J.

    2010-07-01

    The fire simulation and analytical validation procedures have been gaining importance in the context of safety analysis and probabilistic deterministic Fire at Nuclear Power Plants. Meanwhile, the fire simulation codes have been accepted as valuable tools for risk analysis in fire protection. To evaluate the quality and predictability of the codes used in fire protection, they are validated with different experiments. This work is performed to find the dependency of the FDS output parameters against a certain input.

  3. Probabilistic fire simulator - Monte Carlo simulation tool for fire scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Hostikka, S.; Keski-Rahkonen, O. [VTT Building and Transport, Espoo (Finland)

    2002-11-01

    Risk analysis tool is developed for computing of the distributions of fire model output variables. The tool, called Probabilistic Fire Simulator, combines Monte Carlo simulation and CFAST two-zone fire model. In this work, it is used to calculate failure probability of redundant cables and fire detector activation times in a cable tunnel fire. Sensitivity of the output variables to the input variables is calculated in terms of the rank order correlations. (orig.)

  4. Optimization of investment economic in PCI using the methodology of benefits design in analysis of the spread of fires with FDS (Fire Dynamics Simulator) in areas of nuclear fire; Optimizacion de la inversion economica en PCI mediante la metodologia de diseo prestaional en el analisis de la propagacion de incendios con FDS (Fire Dynnamics Simulator) en areas de fuego de centrales nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Salellas, J.

    2015-07-01

    Fire simulation analysis allows knowing the evolution and spread fire in areas of interest within a NPP such as control room, cable room and multi zone comportment among others. fires are a main concern regarding safety analysis of NPP. IDOM has the capability to carry out fire simulations, taken in to account smoke control, fire spread, toxicity levels, ventilation and all physical phenomena. As a result, appropriate fire protection measures can be assessed in each scenario. CFD tools applied to fire simulations can determine with higher resolution all damages caused during the fire. Furthermore, such tools can reduce costs due to a lower impact of design modifications. (Author)

  5. Simulation analysis of the spread of fire through the program Fire Dynamics Simulator FDS in areas of fire of nuclear power plants; Analisis de simulacion de la propagacion de incendios mediante el programa Fire Dynamics Simulator FDS en areas de fuego de Centrales Nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Salellas, J.; Zamora, I.; Fabbri, M.; Colomer, C.; Castillo, R.; Fradera, J.

    2014-07-01

    The objective of the analysis of the spread of fire through Computational Fluid Dynamics simulation with the Fire Dynamics Simulator program is to determine the identification of the affected computers and determine the livability in the areas of fire as fire postulates. The simulation with Fire Dynamics Simulator allows the evolution and spread of flame and smoke behavior in an instant in time, determining the exact moment that damage is caused by radiation or temperature to equipment and operation according to the level of toxicity and temperature of the fire area. (Author)

  6. Probabilistic simulation of fire scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Hostikka, Simo E-mail: simo.bostikka@vtt.fi; Keski-Rahkonen, Olavi

    2003-10-01

    A risk analysis tool is developed for computation of the distributions of fire model output variables. The tool, called Probabilistic Fire Simulator (PFS), combines Monte Carlo simulation and CFAST, a two-zone fire model. In this work, the tool is used to estimate the failure probability of redundant cables in a cable tunnel fire, and the failure and smoke filling probabilities in an electronics room during an electronics cabinet fire. Sensitivity of the output variables to the input variables is calculated in terms of the rank order correlations. The use of the rank order correlations allows the user to identify both modelling parameters and actual facility properties that have the most influence on the results. Various steps of the simulation process, i.e. data collection, generation of the input distributions, modelling assumptions, definition of the output variables and the actual simulation, are described.

  7. Simulation and analysis of airflow stability during fire in mine belt roadway

    Institute of Scientific and Technical Information of China (English)

    ZHANG Sheng-zhu; CHENG Wei-min; LI Qiu-jin; ZHANG Rui; LUO Chuan-long

    2010-01-01

    According to fluid dynamics analysis during the fire, the criteria k-ε two-equation model for solving three-dimensional turbulence was determined, the pollutants generated in the fire disaster were set by adopting Mixture multiphase flow, and the SIMPLE algorithm was used for solving on the basis of comprehensive consideration on the heat radiation and components transmission during fire. By simulating the airflow flowing state inside the tunnel during fire disaster of downward ventilation, drift ventilation, and ascensional ventilation, respectively, with regard to the actual situation of No.1, No.3, and No.5 belt roadway in Kongzhuang Coal Mine, the velocity vector distributions of pollutants under different inlet air volumes were obtained, and the damage degree and influential factors of disaster were also clear, which is helpful to control and avoid disaster during belt roadway fire.

  8. CERN Fire Brigade rescue simulation

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    The CERN Fire Brigade is made up of experienced firemen from all of the 20 Member States. In these images they are seen at a 'Discovery Monday' held at the Microcosm exhibition. Here visitors learn how the Fire Brigade deal with various situations, including a simulated cave rescue performed by the Hazardous Environments Response Team.

  9. Simulating Building Fires for Movies

    Science.gov (United States)

    Rodriguez, Ricardo C.; Johnson, Randall P.

    1987-01-01

    Fire scenes for cinematography staged at relatively low cost in method that combines several existing techniques. Nearly realistic scenes, suitable for firefighter training, produced with little specialized equipment. Sequences of scenes set up quickly and easily, without compromising safety because model not burned. Images of fire, steam, and smoke superimposed on image of building to simulate burning of building.

  10. PF-4 simulated fire accident analysis: Filter-spray cool-down system reevaluation implications

    Energy Technology Data Exchange (ETDEWEB)

    White, B.W.; Gregory, W.S.

    1990-10-01

    The Los Alamos National Laboratory PF-4 facility was designed with spray cool down systems within the building's ventilation systems. The Engineering and Safety Analysis Group was asked, in cooperation with ENG-8 and MST-8, to evaluate whether the spray cool-down system still need to be classified as safety class'' systems. The study was performed using the FIRAC computer code. Given the fire source terms (hypothetical fire energy or time-temperature history), FIRAC can predict the pertinent transient flow parameters (pressures, flows, and temperatures) throughout a previously defined and selected fire zone. A computer model for the study that had all of the main ventilation systems in the south half of the PF-4 facility was used. Because the most hazardous room is located in the 400 Section, all ventilation systems but the 400 Section's one were simplified. The impetus for simplification was to keep the computer model tractable, and this was possible with the following assumptions: the fire cannot spread from one room to another, all corridor connecting doors are closed and will not fail under the pressures generated by the fire, and the principal pathway for potential release is the ventilation system. All of the blowers continue to operate, and all fire retardant systems fail to operate during the fire. The ASTM time-temperature curve was the source for the burn-room temperature, and smoke injection was used as input as well. Five different computer runs were made using different combinations of source terms and heat transfer. A connection from the burn room to the glovebox ventilation system was created by burning the glovebox plastic shielding; it was modeled by a branch having an initial flow 75 ft{sup 3}/min. 7 refs., 35 refs., 15 tabs.

  11. Analysis of thermal response of phenolic foam specimens in a simulated JP-4 fuel fire

    Energy Technology Data Exchange (ETDEWEB)

    Laswell, J.E.

    1973-12-11

    NAD Crane has investigated various phenolic foam compositions which have excellent insulative thermal properties. Two contracts were let with Avco Systems Division to conduct thermal response tests with their simulated JP-4 fuel fire facility. Specimen densities ranged from 4.24 to 25.8 pounds per cubic foot. Time and temperature measurements were recorded until backface temperatures reached 500-1000. Aircraft fuel.

  12. Reconstruction of an inn fire scene using the Fire Dynamics Simulator (FDS) program.

    Science.gov (United States)

    Chi, Jen-Hao

    2013-01-01

    An inn fire occurring in the middle of the night usually causes a great deal more injuries and deaths. This article examines the case study of an inn fire accident that resulted in the most serious casualties in Taiwan's history. Data based on the official fire investigation report and NFPA921 regulations are used, and the fire scenes are reconstructed using the latest Fire Dynamics Simulator (FDS) program from NIST. The personnel evacuation time and time variants for various fire hazard factors of reconstructive analysis clarify the reason for such a high number of casualties. It reveals that the FDS program has come to play an essential role in fire investigation. The close comparison between simulation result and the actual fire scene also provides fire prevention engineers, a possible utilization of FDS to examine the effects of improved schemes for fire safety of buildings.

  13. Computer simulation of the fire-tube boiler hydrodynamics

    Directory of Open Access Journals (Sweden)

    Khaustov Sergei A.

    2015-01-01

    Full Text Available Finite element method was used for simulating the hydrodynamics of fire-tube boiler with the ANSYS Fluent 12.1.4 engineering simulation software. Hydrodynamic structure and volumetric temperature distribution were calculated. The results are presented in graphical form. Complete geometric model of the fire-tube boiler based on boiler drawings was considered. Obtained results are suitable for qualitative analysis of hydrodynamics and singularities identification in fire-tube boiler water shell.

  14. Computer simulation of the fire-tube boiler hydrodynamics

    OpenAIRE

    Khaustov Sergei A.; Zavorin Alexander S.; Buvakov Konstantin V.; Sheikin Vyacheslav A.

    2015-01-01

    Finite element method was used for simulating the hydrodynamics of fire-tube boiler with the ANSYS Fluent 12.1.4 engineering simulation software. Hydrodynamic structure and volumetric temperature distribution were calculated. The results are presented in graphical form. Complete geometric model of the fire-tube boiler based on boiler drawings was considered. Obtained results are suitable for qualitative analysis of hydrodynamics and singularities identification in fire-tube boiler water shell.

  15. FIRE HAZARDS ANALYSIS - BUSTED BUTTE

    Energy Technology Data Exchange (ETDEWEB)

    R. Longwell; J. Keifer; S. Goodin

    2001-01-22

    The purpose of this fire hazards analysis (FHA) is to assess the risk from fire within individual fire areas at the Busted Butte Test Facility and to ascertain whether the DOE fire safety objectives are met. The objective, identified in DOE Order 420.1, Section 4.2, is to establish requirements for a comprehensive fire and related hazards protection program for facilities sufficient to minimize the potential for: (1) The occurrence of a fire related event. (2) A fire that causes an unacceptable on-site or off-site release of hazardous or radiological material that will threaten the health and safety of employees. (3) Vital DOE programs suffering unacceptable interruptions as a result of fire and related hazards. (4) Property losses from a fire and related events exceeding limits established by DOE. Critical process controls and safety class systems being damaged as a result of a fire and related events.

  16. Theoretical analysis and numerical simulation on behaviour properties of large span cable-supported structures under fire conditions

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Large span cable-supported structures have been developed rapidly in China, and they always adopt high-strength steel cables as structural members. However, the modulus of elasticity and yield strength of steel material will decrease seriously under fire conditions while fire protection is unlikely to be provided for steel cable. Several typical large span cable-supported structures such as cable truss, beam string structure and prestressed cable net are studied on their structural behaviour in this paper. Theoretical formulae are derived in terms of geometrical and material nonlinearity with high temperature effect. Finite element models are also established to simulate the structural performance under fire conditions. The calculation formulae for fire-resisting design are suggested for these three types of structures, while displacement and prestressed force variation rules are also given.

  17. Theoretical analysis and numerical simulation on behaviour properties of large span cable-supported structures under fire conditions

    Institute of Scientific and Technical Information of China (English)

    BAI Yin; SHI YongJiu; WANG YuanQing

    2009-01-01

    Large span cable-supported structures have been developed rapidly in China,and they always adopt high-strength steel cables as structural members.However,the modulus of elasticity and yield strength of steel material will decrease seriously under fire conditions while fire protection is unlikely to be provided for steel cable.Several typical large span cable-supported structures such as cable truss,beam string structure and prestressed cable net are studied on their structural behaviour in this paper.Theoretical formulae are derived in terms of geometrical and material nonlinearity with high temperature effect.Finite element models are also established to simulate the structural performance under fire conditions.The calculation formulae for fire-resisting design are suggested for these three types of structures,while displacement and prestressed force variation rules are also given.

  18. Simulation of the 2009 Harmanli fire (Bulgaria)

    CERN Document Server

    Jordanov, Georgi; Dobrinkova, Nina; Kochanski, Adam K; Mandel, Jan; Sousedík, Bedřich

    2011-01-01

    We use a coupled atmosphere-fire model to simulate a fire that occurred on August 14--17, 2009, in the Harmanli region, Bulgaria. Data was obtained from GIS and satellites imagery, and from standard atmospheric data sources. Fuel data was classified in the 13 Anderson categories. For correct fire behavior, the spatial resolution of the models needed to be fine enough to resolve the essential micrometeorological effects. The simulation results are compared to available incident data. The code runs faster than real time on a cluster. The model is available from openwfm.org and it extends WRF-Fire from WRF 3.3 release.

  19. Issues in Numerical Simulation of Fire Suppression

    Energy Technology Data Exchange (ETDEWEB)

    Tieszen, S.R.; Lopez, A.R.

    1999-04-12

    This paper outlines general physical and computational issues associated with performing numerical simulation of fire suppression. Fire suppression encompasses a broad range of chemistry and physics over a large range of time and length scales. The authors discuss the dominant physical/chemical processes important to fire suppression that must be captured by a fire suppression model to be of engineering usefulness. First-principles solutions are not possible due to computational limitations, even with the new generation of tera-flop computers. A basic strategy combining computational fluid dynamics (CFD) simulation techniques with sub-grid model approximations for processes that have length scales unresolvable by gridding is presented.

  20. COMPUTATIONAL SIMULATION OF FIRE DEVELOPMENT INSIDE A TRADE CENTRE

    Directory of Open Access Journals (Sweden)

    Constantin LUPU

    2015-07-01

    Full Text Available Real scale fire experiments involve considerable costs compared to computational mathematical modelling. This paperwork is the result of such a virtual simulation of a fire occurred in a hypothetical wholesale warehouse comprising a large number of trade stands. The analysis starts from the ignition source located inside a trade stand towards the fire expansion over three groups of compartments, by highlighting the heat transfer, both in small spaces, as well as over large distances. In order to confirm the accuracy of the simulation, the obtained values are compared to the ones from the specialized literature.

  1. Numerical analysis on spreading laws of grassland fire based on fire dynamics simulator (FDS)%基于火灾模拟软件(FDS)的草原火灾蔓延规律数值分析

    Institute of Scientific and Technical Information of China (English)

    辛喆; 王顺喜; 云峰; 管清云; 何也能

    2013-01-01

    Grassland is an important land resource in China. Grassland fire is one of the worst natural disasters which threaten the safety of herdsmen’s lives and properties and ecological environment in the country. Due to vast territory, rich combustible and low rainfall of grassland, grassland fire has the features of suddenly happening, huge destruction and large influence area. As to organize fire suppression efficiently and reduce losses from fires, it has important significance to conduct the research on spreading laws of grassland fire under different influencing factors and on forecasting spreading trend of grassland fire duly. The researches on behaviors of grassland and forest fires at home and aboard are mainly based on field observation and laboratory experiments, several important factors being seized through those. Moreover according to laws of statistics and physics, corresponding mathematical models are developed lastly for estimating the properties of wildfires. Researches on spreading laws and models of grassland and forest fires are mainly focused on forest fires at present. Grassland fires are often analyzed on the basis of the existing models of forest fires. In more recent years, it has been adopted by researchers gradually to forecast behaviors of grassland and forest fires with computer simulation. FDS (Fire Dynamics Simulator) is the software of computational fluid dynamics to simulate fluid-flow in fires developed by NIST (National Institute of Standards and Technology) in USA. Numerical approach has been developed by the software to solve Navier-Stokes equations of flow of low Mach number. Afterwards gas and process of heat transfer in fires have been calculated especially, through those the producing and move of gas in fires could be tracked and forecasted, so as to calculate the producing and spreading of fires. In the paper, the simplified model of grassland fire has been created for a practical pasture with FDS firstly. Correlation analysis

  2. Fire Simulation and Cardiovascular Health in Firefighters

    Science.gov (United States)

    Hunter, Amanda L.; Shah, Anoop S.V.; Langrish, Jeremy P.; Raftis, Jennifer B.; Lucking, Andrew J.; Brittan, Mairi; Venkatasubramanian, Sowmya; Stables, Catherine L.; Stelzle, Dominik; Marshall, James; Graveling, Richard; Flapan, Andrew D.; Newby, David E.

    2017-01-01

    Background: Rates of myocardial infarction in firefighters are increased during fire suppression duties, and are likely to reflect a combination of factors including extreme physical exertion and heat exposure. We assessed the effects of simulated fire suppression on measures of cardiovascular health in healthy firefighters. Methods: In an open-label randomized crossover study, 19 healthy firefighters (age, 41±7 years; 16 males) performed a standardized training exercise in a fire simulation facility or light duties for 20 minutes. After each exposure, ex vivo thrombus formation, fibrinolysis, platelet activation, and forearm blood flow in response to intra-arterial infusions of endothelial-dependent and -independent vasodilators were measured. Results: After fire simulation training, core temperature increased (1.0±0.1°C) and weight reduced (0.46±0.14 kg, PURL: http://www.clinicaltrials.gov. Unique identifier: NCT01812317. PMID:28373523

  3. Efficient algorithms for wildland fire simulation

    Science.gov (United States)

    Kondratenko, Volodymyr Y.

    In this dissertation, we develop the multiple-source shortest path algorithms and examine their application importance in real world problems, such as wildfire modeling. The theoretical basis and its implementation in the Weather Research Forecasting (WRF) model coupled with the fire spread code SFIRE (WRF-SFIRE model) are described. We present a data assimilation method that gives the fire spread model the ability to start the fire simulation from an observed fire perimeter instead of an ignition point. While the model is running, the fire state in the model changes in accordance with the new arriving data by data assimilation. As the fire state changes, the atmospheric state (which is strongly effected by heat flux) does not stay consistent with the fire state. The main difficulty of this methodology occurs in coupled fire-atmosphere models, because once the fire state is modified to match a given starting perimeter, the atmospheric circulation is no longer in sync with it. One of the possible solutions to this problem is a formation of the artificial time of ignition history from an earlier fire state, which is later used to replay the fire progression to the new perimeter with the proper heat fluxes fed into the atmosphere, so that the fire induced circulation is established. In this work, we develop efficient algorithms that start from the fire arrival times given at the set of points (called a perimeter) and create the artificial fire time of ignition and fire spread rate history. Different algorithms were developed in order to suit possible demands of the user, such as implementation in parallel programming, minimization of the required amount of iterations and memory use, and use of the rate of spread as a time dependent variable. For the algorithms that deal with the homogeneous rate of spread, it was proven that the values of fire arrival times they produce are optimal. It was also shown that starting from arbitrary initial state the algorithms have

  4. 水下隧道火灾烟气数值模拟研究%The Simulation of Fire Smoke in the Tunnel under Water and the Analysis

    Institute of Scientific and Technical Information of China (English)

    梁晖; 李天立

    2012-01-01

    结合公路隧道火灾特点,利用FDS对某过江隧道中规模为20MW的火灾烟气进行了模拟计算。通过比较、分析和总结不同纵向通风风速条件下的隧道火灾烟气和温度的分布特点,得到了临界风速的模拟值及使得排烟效果最佳时的纵向风速,对隧道防排烟设计及火灾应急预案的制定具有参考意义。%This paper, combining the characteristics of a road tunnel fire, employs FDS to simulate the fire smoke of 20MW size in the Tunnel. Through the comparison, analysis and induction on the distribution characteristics of the smoke and the temperature under a different longitudinal ventilation velocity in a tunnel fire, the analog value of a critical ventilation and the analog value of a vertical ventilation which would be best for controling and sweeping the smoke were obtained. They supply the key to the design of a smoke management system in the Tunnel and are of sig- nificance in a fire emergency plan.

  5. Two typical phenomena from the numerical simulation of fire and smoke transport in a gymnasium fire

    Institute of Scientific and Technical Information of China (English)

    CHEN Jianguo; CHEN Haixin; FU Song

    2006-01-01

    Navier-Stokes equations are solved to simulate a gymnasium fire. The equations are simplified by weakly compressible low Mach number assumption. Turbulence effect is simulated using Smagorinsky large eddy simulation (LES) model. The mixture fraction combustion model is adopted to simulate the burning process. With the analysis of computed velocity and temperature field, two important phenomena, named door effect and smoke plug-holing, are found to be responsible for the deterioration of smoke exhaust efficiency when natural ventilation or forced ventilation is present. Some explanations are made to elucidate these effects' mechanism. An improved design of smoke ventilation system is suggested.

  6. Data Assimilation of Satellite Fire Detection in Coupled Atmosphere-Fire Simulation by WRF-SFIRE

    CERN Document Server

    Mandel, Jan; Vejmelka, Martin; Beezley, Jonathan D

    2014-01-01

    Currently available satellite active fire detection products from the VIIRS and MODIS instruments on polar-orbiting satellites produce detection squares in arbitrary locations. There is no global fire/no fire map, no detection under cloud cover, false negatives are common, and the detection squares are much coarser than the resolution of a fire behavior model. Consequently, current active fire satellite detection products should be used to improve fire modeling in a statistical sense only, rather than as a direct input. We describe a new data assimilation method for active fire detection, based on a modification of the fire arrival time to simultaneously minimize the difference from the forecast fire arrival time and maximize the likelihood of the fire detection data. This method is inspired by contour detection methods used in computer vision, and it can be cast as a Bayesian inverse problem technique, or a generalized Tikhonov regularization. After the new fire arrival time on the whole simulation domain is...

  7. A CFD Validation of Fire Dynamics Simulator for ‎Corner Fire

    Directory of Open Access Journals (Sweden)

    Pavan K. Sharma

    2010-12-01

    Full Text Available A computational study has been carried out for predicting the behaviour of a corner fire ‎source for a ‎reported experiment using a field model based code Fire Dynamics Simulator ‎‎(FDS. Time ‎dependent temperature is predicted along with the resulting changes in the ‎plume structure. The flux ‎falling on the wall was also observed. The analysis has been ‎carried out with the correct value of the ‎grid size based on earlier experiences and also by ‎performing a grid sensitivity study. The predicted ‎temperatures of the two scenarios at two ‎points by the current analysis are in very good agreement ‎with the earlier reported ‎experimental data and numerical prediction. The studies have extended the ‎utility of field ‎model based tools to model the particular separate effect phenomenon like corner for ‎one ‎such situation and validate against experimental data. The present study have several ‎‎applications in such as room fires, hydrogen transport in nuclear reactor containment, ‎natural ‎convection in building flows etc. The present approach uses the advanced Large ‎Eddy Simulation ‎‎(LES based CFD turbulence model. The paper presents brief description ‎of the code FDS, details ‎of the computational model along with the discussions on the ‎results obtained under these studies. ‎The validated CFD based procedure has been used for ‎solving various problems enclosure fire, ‎ventilated fire and open fire from nuclear industry ‎which are however not included in the present ‎paper. ‎

  8. Improvement and upgrade of mine fire simulation program MFIRE

    Institute of Scientific and Technical Information of China (English)

    ZHOU Li-hong; LUO Yi

    2011-01-01

    MFIRE,an underground mine fire simulation program developed in 1980's,is a tool that can be used to simulate the impacts of a mine fire event to a mine ventilation network.However,the lack of the abilities to simulate some of the important mine fire phenomena realistically hindered its wide applications.This research carried out to improve and upgrade the MFIRE 2.20 program to MFIRE 2.30.The new additions of MFIRE 2.30 including a time dependent fire model,smoke rollback prediction,the incorporation of a moving fire source,and a rewriting of MFIRE in Microsoft Visual C++ were interpreted.

  9. A case study on fractal simulation of forest fire spread

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper relates to the semi-empirical model based on fire field energy balance and the physical model based on land temperature,aiming to provide a practical way of describing fire spread.Fire spread is determined by the characteristics of combustible materials and the agency of meteorological factors and terrains.Combustible materials,such as surface area,have no featured scale,yet the process of forest fire spread contains the self-replicating feature,both of which contribute to the self-similarity of fire spread.Consequently,fire behavior can be described by fractal geometry.In this research,we select Wuchagou forest in Da Hinggan Mountains as the experimental site where a forest fire took place three years ago.The forest fire was detected on low-resolution NOAA-AVHRR images,and fire spread was simulated on high-resolution TM images as another attempt to merge information.Based on remote sensing and GIS,we adopted the method of limited spreading lumping (DLA) to describe growing phenomenon to simulate the dynamic process of fire spread and adjusting shape of the result of fire simulation by the scale rule.As a result,the simulated fire and the actual fire manifest the self-similarity in their spreading shapes as well as the quantitative similarity in their areas.

  10. Quantitative application of Monte Carlo simulation in Fire-PSA

    Energy Technology Data Exchange (ETDEWEB)

    Mangs, J.; Hostikka, S.; Korhonen, T. [Valtion Teknillinen Tutkimuskeskus, Espoo (Finland); Keski-Rahkonen, O.

    2007-05-15

    In a power plant a fire cell forms the basic subunit. Since the fire is initially located there, the full-scale time dependent fire simulation and estimation of target response must be performed within the fire cell. Conditional, time dependent damage probabilities in a fire cell can now be calculated for arbitrary targets (component or a subsystem) combining probabilistic (Monte Carlo) and deterministic simulation. For the latter a spectrum from simple correlations up to latest computational fluid dynamics models is available. Selection of the code is made according to the requirements form the target cell. Although calculations are numerically heavy, it is now economically possible and feasible to carry out quantitative fire-PSA for a complete plant iteratively with the main PSA. From real applications examples are shown on assessment of fire spread possibility in a relay room, and potential of fire spread on cables in a tunnel. (orig.)

  11. 3D Simulation of a Medium scale Pool Fire

    Directory of Open Access Journals (Sweden)

    Naveen S

    2014-04-01

    Full Text Available Pool fires represent the most frequently encountered accidents of the different types of fires that are known to occur in the Chemical Process Industry (CPI. Exhaustive analysis of the history of past accidents in CPI's that have occurred across the world since early 1900's reveal that pool fires are major threats to industrial safety, and result in huge losses of life and property. Studies have been going on to study the interaction mechanisms of the fire and models have been developed which were mostly empirical, zone models and field models developed according to and based on the conditions available for the experiment. The experiment considered consisted of a 2-m-diameter methanol pool in an unconfined area with a cross-wind velocity of 13 m/s. Steady state simulations with uniform time step were done using computational fluid dynamics and the simulations showed sensitivity to the grid refinement, size of the pool and wind profiles.Comparison between calculated and experimental results are also made.Turbulence models were also investigated, and was observed that RNG model gave more predictable results for the test cases to the accuracy of almost 80%.

  12. Numerical simulation of a biomass fired grate boiler

    DEFF Research Database (Denmark)

    Yin, Chungen; Rosendahl, Lasse; Kær, Søren Knudsen

    2006-01-01

    Computational fluid dynamic (CFD) analysis of the thermal flow in the combustion furnace of a biomass-fired grate boiler provides crucial insight into the boiler's performance. Quite a few factors play important roles in a general CFD analysis, such as grid, models, discretization scheme and so on....... For a grate boiler, the modeling the interaction of the fuel bed and the gas phase above the bed is also essential. Much effort can be found in literature on developing bed models whose results are introduced into CFD simulations of freeboard as inlet conditions. This paper presents a CFD analysis...... of the largest biomass-fired grate boiler in Denmark. The focus of this paper is to study how significantly an accurate bed model can affect overall CFD results, i.e., how necessarily it is to develop an accurate bed model in terms of the reliability of CFD results. The ultimate purpose of the study is to obtain...

  13. FireStem2D--a two-dimensional heat transfer model for simulating tree stem injury in fires.

    Directory of Open Access Journals (Sweden)

    Efthalia K Chatziefstratiou

    Full Text Available FireStem2D, a software tool for predicting tree stem heating and injury in forest fires, is a physically-based, two-dimensional model of stem thermodynamics that results from heating at the bark surface. It builds on an earlier one-dimensional model (FireStem and provides improved capabilities for predicting fire-induced mortality and injury before a fire occurs by resolving stem moisture loss, temperatures through the stem, degree of bark charring, and necrotic depth around the stem. We present the results of numerical parameterization and model evaluation experiments for FireStem2D that simulate laboratory stem-heating experiments of 52 tree sections from 25 trees. We also conducted a set of virtual sensitivity analysis experiments to test the effects of unevenness of heating around the stem and with aboveground height using data from two studies: a low-intensity surface fire and a more intense crown fire. The model allows for improved understanding and prediction of the effects of wildland fire on injury and mortality of trees of different species and sizes.

  14. Computer simulation of combustion of mine fires

    Institute of Scientific and Technical Information of China (English)

    余明高; 张和平; 范维澄; 王清安

    2002-01-01

    According to control theories, mine fires can be considered as an unsteady process after the normal ventilation system is disturbed. Applied the principal of physical chemistry and thermal fluid mechanics, the parameters models of the unsteady state system have been given, such as fuel combustion rate, heat of combustion, concentration, temperature, heat losses, heat resistance, work of expansion and heat pressure difference. The results of the calculation agree approximately with the results of the test. By the computer simulation, it is shown that the main factor of producing the throttling effect is the fire rate, second is the heat resistance and the heat pressure difference. The rate of heat flow that passes through the airway wall is the maximum on the surface, and decrease with time. The heat transfer progresses only within the range of 0.5 m away from theairway wall during combustion for 2 hours. Its variable for the mass flux rate and the percentage concentration of the gas along the airway of the downstream. When the delayed time is very small, the variation can be neglected. Viscosity resistance is the main part of the heat resistance, second is the expansion resistance that is less than tens Pascal when Mach number is very small. Work of expansion is principally turned into heat losses, only a very small part is consumed by the work of the heat resistance and the inertia acceleration.

  15. Fire hazard analysis for fusion energy experiments

    Energy Technology Data Exchange (ETDEWEB)

    Alvares, N.J.; Hasegawa, H.K.

    1979-01-01

    The 2XIIB mirror fusion facility at Lawrence Livermore Laboratory (LLL) was used to evaluate the fire safety of state-of-the-art fusion energy experiments. The primary objective of this evaluation was to ensure the parallel development of fire safety and fusion energy technology. Through fault-tree analysis, we obtained a detailed engineering description of the 2XIIB fire protection system. This information helped us establish an optimum level of fire protection for experimental fusion energy facilities as well as evaluate the level of protection provided by various systems. Concurrently, we analyzed the fire hazard inherent to the facility using techniques that relate the probability of ignition to the flame spread and heat-release potential of construction materials, electrical and thermal insulations, and dielectric fluids. A comparison of the results of both analyses revealed that the existing fire protection system should be modified to accommodate the range of fire hazards inherent to the 2XIIB facility.

  16. Exploratory Studies Facility Subsurface Fire Hazards Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Richard C. Logan

    2002-03-28

    The primary objective of this Fire Hazard Analysis (FHA) is to confirm the requirements for a comprehensive fire and related hazards protection program for the Exploratory Studies Facility (ESF) are sufficient to minimize the potential for: The occurrence of a fire or related event; A fire that causes an unacceptable on-site or off-site release of hazardous or radiological material that will threaten the health and safety of employees, the public or the environment; Vital U.S. Department of Energy (DOE) programs suffering unacceptable interruptions as a result of fire and related hazards; Property losses from a fire and related events exceeding limits established by DOE; and Critical process controls and safety class systems being damaged as a result of a fire and related events.

  17. Exploratory Studies Facility Subsurface Fire Hazards Analysis

    Energy Technology Data Exchange (ETDEWEB)

    J. L. Kubicek

    2001-09-07

    The primary objective of this Fire Hazard Analysis (FHA) is to confirm the requirements for a comprehensive fire and related hazards protection program for the Exploratory Studies Facility (ESF) are sufficient to minimize the potential for: (1) The occurrence of a fire or related event. (2) A fire that causes an unacceptable on-site or off-site release of hazardous or radiological material that will threaten the health and safety of employees, the public or the environment. (3) Vital US. Department of Energy (DOE) programs suffering unacceptable interruptions as a result of fire and related hazards. (4) Property losses from a fire and related events exceeding limits established by DOE. (5) Critical process controls and safety class systems being damaged as a result of a fire and related events.

  18. Leader neurons in leaky integrate and fire neural network simulations.

    Science.gov (United States)

    Zbinden, Cyrille

    2011-10-01

    In this paper, we highlight the topological properties of leader neurons whose existence is an experimental fact. Several experimental studies show the existence of leader neurons in population bursts of activity in 2D living neural networks (Eytan and Marom, J Neurosci 26(33):8465-8476, 2006; Eckmann et al., New J Phys 10(015011), 2008). A leader neuron is defined as a neuron which fires at the beginning of a burst (respectively network spike) more often than we expect by chance considering its mean firing rate. This means that leader neurons have some burst triggering power beyond a chance-level statistical effect. In this study, we characterize these leader neuron properties. This naturally leads us to simulate neural 2D networks. To build our simulations, we choose the leaky integrate and fire (lIF) neuron model (Gerstner and Kistler 2002; Cessac, J Math Biol 56(3):311-345, 2008), which allows fast simulations (Izhikevich, IEEE Trans Neural Netw 15(5):1063-1070, 2004; Gerstner and Naud, Science 326:379-380, 2009). The dynamics of our lIF model has got stable leader neurons in the burst population that we simulate. These leader neurons are excitatory neurons and have a low membrane potential firing threshold. Except for these two first properties, the conditions required for a neuron to be a leader neuron are difficult to identify and seem to depend on several parameters involved in the simulations themselves. However, a detailed linear analysis shows a trend of the properties required for a neuron to be a leader neuron. Our main finding is: A leader neuron sends signals to many excitatory neurons as well as to few inhibitory neurons and a leader neuron receives only signals from few other excitatory neurons. Our linear analysis exhibits five essential properties of leader neurons each with different relative importance. This means that considering a given neural network with a fixed mean number of connections per neuron, our analysis gives us a way of

  19. Personnel evacuation simulation analysis of the supermarket under fire situation%大型超市火灾情况下人员疏散模拟分析

    Institute of Scientific and Technical Information of China (English)

    季经纬; 武爽; 赵平; 张敬瑶

    2011-01-01

    针对大型商场在火灾情况下,人员是否能够及时逃生的问题,采用计算流体动力学软件FDS和大型疏散模拟软件building EXODUS对徐州某大型超市进行火灾时人员疏散的模拟.在火灾场景下,由于烟气对于人员顺利逃生有着重要的影响,运用FDS软件模拟得到着火层四周出口处烟气的下降速度,烟气浓度以及能见度的变化情况,从而给出人员安全疏散的最佳时间,再应用building EXODUS模拟当超市人流量最大时人员的疏散情况,得出该大型超市内人员逃生所需的时间,两种模拟所得时间进行对比分析,可得到人员是否能安全疏散的结论.%For if the people can evacuate timely when in case of catching fire in the large supermarket, in this paper the computational fluid dynamics software FDS and the evacuation simulation software building EXODUS were applied to simulate the personnel evacuation under the fire condition in the large supermarket of Xuzhou, then the best time for the person in the supermarket to escape under fire condition was obtained. The affects of the smoke changes with time to the personnel escape under the fire condition were analyzed, and FDS was used to simulate the rate of the smoke declines around the exits on the fire floor, the changes of the smoke concentration and the visibility, then according to this FDS simulation, the best time for the person in the building to escape could be obtained, also the building EXODUS software was used to simulate the evacuation of people, the time of the escape simulation in the supermarket could be obtained, using this two times of the two simulations result, it could be analyed that if the person can escape from the building timely, and it can provide reference for the performance-based fire design of the building.

  20. A review of wildland fire spread modelling, 1990-present 3: Mathematical analogues and simulation models

    CERN Document Server

    Sullivan, A L

    2007-01-01

    In recent years, advances in computational power and spatial data analysis (GIS, remote sensing, etc) have led to an increase in attempts to model the spread and behvaiour of wildland fires across the landscape. This series of review papers endeavours to critically and comprehensively review all types of surface fire spread models developed since 1990. This paper reviews models of a simulation or mathematical analogue nature. Most simulation models are implementations of existing empirical or quasi-empirical models and their primary function is to convert these generally one dimensional models to two dimensions and then propagate a fire perimeter across a modelled landscape. Mathematical analogue models are those that are based on some mathematical conceit (rather than a physical representation of fire spread) that coincidentally simulates the spread of fire. Other papers in the series review models of an physical or quasi-physical nature and empirical or quasi-empirical nature. Many models are extensions or ...

  1. Application of Computer Integration Technology for Fire Safety Analysis

    Institute of Scientific and Technical Information of China (English)

    SHI Jianyong; LI Yinqing; CHEN Huchuan

    2008-01-01

    With the development of information technology, the fire safety assessment of whole structure or region based on the computer simulation has become a hot topic. However, traditionally, the concemed studies are performed separately for different objectives and difficult to perform an overall evaluation. A new multi-dimensional integration model and methodology for fire safety assessment were presented and two newly developed integrated systems were introduced to demonstrate the function of integration simulation technology in this paper. The first one is the analysis on the fire-resistant behaviors of whole structure under real fire loads. The second one is the study on fire evaluation and emergency rescue of campus based on geography information technology (GIS). Some practical examples are presented to illuminate the advan-tages of computer integration technology on fire safety assessment and emphasize some problems in the simulation. The results show that the multi-dimensional integration model offers a new way and platform for the integrating fire safety assessment of whole structure or region, and the integrated software developed is the useful engineering tools for cost-saving and safe design.

  2. Turbulence and fire-spotting effects into wild-land fire simulators

    CERN Document Server

    Kaur, Inderpreet; Bosseur, Frédéric; Filippi, Jean-Baptiste; Pagnini, Gianni

    2016-01-01

    This paper presents a mathematical approach to model the effects and the role of phenomena with random nature such as turbulence and fire-spotting into the existing wildfire simulators. The formulation proposes that the propagation of the fire-front is the sum of a drifting component (obtained from an existing wildfire simulator without turbulence and fire-spotting) and a random fluctuating component. The modelling of the random effects is embodied in a probability density function accounting for the fluctuations around the fire perimeter given by the drifting component. In past, this formulation has been applied to include these random effects into a wildfire simulator based on an Eulerian moving interface method, namely the Level Set Method (LSM), but in this paper the same formulation is adapted for a wildfire simulator based on a Lagrangian front tracking technique, namely the Discrete Event System Specification (DEVS). Simple idealised numerical experiments are used to compare the performances of the LSM...

  3. Simulation of smoke flow and longitudinal ventilation in tunnel fire

    Institute of Scientific and Technical Information of China (English)

    YANG Gao-shang; AN Yong-lin; PENG Li-min; ZHANG Jin-hua

    2006-01-01

    Understanding the characteristics of smoke flow in tunnel fire is very important for tunnel safety. The characteristics of tunnel fire were analyzed. The smoke development in different situations of an engineering example was simulated using commercial CFD software PHOENICS 3.5 by field modeling method. The spreading rules and characteristics of concentration field and temperature field of smoke flow with different longitudinal ventilation speeds were studied, which may provide the theoretical background for evacuation design in tunnel fire. The effective measures of fire rescue and crowd evacuation were also described.

  4. A note on parallel efficiency of fire simulation on cluster

    Science.gov (United States)

    Valasek, L.; Glasa, J.

    2016-08-01

    Current HPC clusters are capable to reduce execution time of parallelized tasks significantly. The paper discusses the use of two selected strategies of cluster computational resources allocation and their impact on parallel efficiency of fire simulation. Simulation of a simple corridor fire scenario by Fire Dynamics Simulator parallelized by the MPI programming model is tested on the HPC cluster at the Institute of Informatics of Slovak Academy of Sciences in Bratislava (Slovakia). The tests confirm that parallelization has a great potential to reduce execution times achieving promising values of parallel efficiency of the simulation, however, the results also show that the use of increasing numbers of computational meshes resulting in increasing numbers of used computational cores does not necessarily decrease the execution time nor the parallel efficiency of simulation. The results obtained indicate that the simulation achieves different values of the execution time and the parallel efficiency in regard of the used strategy for cluster computational resources allocation.

  5. A case study on fractal simulation of forest fire spread

    Institute of Scientific and Technical Information of China (English)

    朱启疆; 戎太宗; 孙睿

    2000-01-01

    This paper relates to the semi-empirical model based on fire field energy balance and the physical model based on land temperature, aiming to provide a practical way of describing fire spread. Fire spread is determined by the characteristics of combustible materials and the agency of meteorological factors and terrains. Combustible materials, such as surface area, have no featured scale, yet the process of forest fire spread contains the self-replicating feature, both of which contribute to the self-similarity of fire spread. Consequently, fire behavior can be described by fractal geometry. In this research, we select Wuchagou forest in Da Hinggan Mountains as the experimental site where a forest fire took place three years ago. The forest fire was detected on low-resolution NOAA-AVHRR images, and fire spread was simulated on high-resolution TM images as another attempt to merge information. Based on remote sensing and GIS, we adopted the method of limited spreading lumping (DLA) to describe growing phe

  6. Simulation of a compartment fire using a zone model

    Institute of Scientific and Technical Information of China (English)

    YANG Lizhong; GUO Zaifu; JI Jingwei; FAN Weicheng

    2005-01-01

    This paper presents the zone modeling analysis of a single compartment flashover fire. Two criteria are applied in the model to judge the onset of ignition for different combustibles. By calculating the total received energy through radiation or the surface temperature of the combustible, the fire growth can be quantitatively determined. The improved zone fire model shows the influence of different combustibles upon the fire growth. This model is better than the traditional zone model because the common criteria of flashover, i.e. an upper layer temperature of 600℃ and the heat radiation intensity received by the floor of 20 kW/m2, have not been applied in it.

  7. Fire hazards analysis of transuranic waste storage and assay facility

    Energy Technology Data Exchange (ETDEWEB)

    Busching, K.R., Westinghouse Hanford

    1996-07-31

    This document analyzes the fire hazards associated with operations at the Central Waste Complex. It provides the analysis and recommendations necessary to ensure compliance with applicable fire codes.

  8. Turbulence and fire-spotting effects into wild-land fire simulators

    Science.gov (United States)

    Kaur, Inderpreet; Mentrelli, Andrea; Bosseur, Frédéric; Filippi, Jean-Baptiste; Pagnini, Gianni

    2016-10-01

    This paper presents a mathematical approach to model the effects and the role of phenomena with random nature such as turbulence and fire-spotting into the existing wildfire simulators. The formulation proposes that the propagation of the fire-front is the sum of a drifting component (obtained from an existing wildfire simulator without turbulence and fire-spotting) and a random fluctuating component. The modelling of the random effects is embodied in a probability density function accounting for the fluctuations around the fire perimeter which is given by the drifting component. In past, this formulation has been applied to include these random effects into a wildfire simulator based on an Eulerian moving interface method, namely the Level Set Method (LSM), but in this paper the same formulation is adapted for a wildfire simulator based on a Lagrangian front tracking technique, namely the Discrete Event System Specification (DEVS). The main highlight of the present study is the comparison of the performance of a Lagrangian and an Eulerian moving interface method when applied to wild-land fire propagation. Simple idealised numerical experiments are used to investigate the potential applicability of the proposed formulation to DEVS and to compare its behaviour with respect to the LSM. The results show that DEVS based wildfire propagation model qualitatively improves its performance (e.g., reproducing flank and back fire, increase in fire spread due to pre-heating of the fuel by hot air and firebrands, fire propagation across no fuel zones, secondary fire generation, ...) when random effects are included according to the present formulation. The performance of DEVS and LSM based wildfire models is comparable and the only differences which arise among the two are due to the differences in the geometrical construction of the direction of propagation. Though the results presented here are devoid of any validation exercise and provide only a proof of concept, they show a

  9. Vortical structures in pool fires: Observation, speculation, and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Tieszen, S.R.; Nicolette, V.F.; Gritzo, L.A.; Moya, J.L. [Sandia National Labs., Albuquerque, NM (United States); Holen, J.K. [SINTEF/NTH, Trondheim (Norway). Div. Thermodynamics; Murray, D. [Naval Air Warfare Center, China Lake, CA (United States)

    1996-11-01

    While all fires are complex and involve many phenomena, this report is limited to large, turbulent liquid-hydrocarbon pool fires. Large, liquid-hydrocarbon pool fires present a risk in petrochemical storage and processing facilities and transportation systems that contain large amounts of liquid hydrocarbons. This report describes observations, speculations, and numerical simulations of vortical structures in pool fires. Vortical structures are observed in fires with length scales ranging from those that bend millimeter-thick flame zones to those that entrain air many meters from the edge of the fire to its centerline. The authors propose that baroclinic vorticity generation is primarily responsible for production of rotational motion at small scale and that amalgamation is responsible for the production of large-scale rotational structures from the myriad of small-scale structures. Numerical simulations show that vortical structures having time-mean definitions can be resolved with a Reynolds-Average Navier-Stokes (RANS) approach. However, for vortical structures without time-mean definition, RANS is inappropriate, and another technique, such as Large Eddy Simulation (LES), should be employed. 39 refs., 52 figs., 3 tabs.

  10. Quantitative analysis of forest fire extinction efficiency

    Directory of Open Access Journals (Sweden)

    Miguel E. Castillo-Soto

    2015-08-01

    Full Text Available Aim of study: Evaluate the economic extinction efficiency of forest fires, based on the study of fire combat undertaken by aerial and terrestrial means. Area of study, materials and methods: Approximately 112,000 hectares in Chile. Records of 5,876 forest fires that occurred between 1998 and 2009 were analyzed. The area further provides a validation sector for results, by incorporating databases for the years 2010 and 2012. The criteria used for measuring extinction efficiency were economic value of forestry resources, Contraction Factor analysis and definition of the extinction costs function. Main results: It is possible to establish a relationship between burnt area, extinction costs and economic losses. The method proposed may be used and adapted to other fire situations, requiring unit costs for aerial and terrestrial operations, economic value of the property to be protected and speed attributes of fire spread in free advance. Research highlights: The determination of extinction efficiency in containment works of forest fires and potential projection of losses, different types of plant fuel and local conditions favoring the spread of fire broaden the admissible ranges of a, φ and Ce considerably.

  11. Fire spread simulation of a full scale cable tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Huhtanen, R. [VTT Energy, Espoo (Finland)

    1999-11-01

    A fire simulation of a full scale tunnel was performed by using the commercial code EFFLUENT as the simulation platform. Estimation was made for fire spread on the stacked cable trays, possibility of fire spread to the cable trays on the opposite wall of the tunnel, detection time of smoke detectors in the smouldering phase and response of sprinkler heads in the flaming phase. According to the simulation, the rise of temperature in the smouldering phase is minimal, only of the order 1 deg C. The estimates of optical density of smoke show that normal smoke detectors should give an alarm within 2-4 minutes from the beginning of the smouldering phase, depending on the distance to the detector (in this case it was assumed that the thermal source connected to the smoke source was 50 W). The flow conditions at smoke detectors may be challenging, because the velocity magnitude is rather low at this phase. At 4 minutes the maximum velocity at the detectors is 0.12 m/s. During the flaming phase (beginning from 11 minutes) fire spreads on the stacked cable trays in an expected way, although the ignition criterion seems to perform poorly when ignition of new objects is considered. The Upper cable trays are forced to ignite by boundary condition definitions according to the experience found from ti full scale experiment and an earlier simulation. After 30 minutes the hot layer in the room becomes so hot that it speeds up the fire spread and the rate of heat release of burning objects. Further, the hot layer ignites the cable trays on the opposite wall of the tunnel after 45 minutes. It is estimated that the sprinkler heads would be activated at 20-22 minutes near the fire source and at 24-28 minutes little further from the fire source when fast sprinkler heads are used. The slow heads are activated between 26-32 minutes. (orig.)

  12. Comparative CFD simulations of a hydrogen fire scenario

    Science.gov (United States)

    Nobili, M.; Caruso, G.

    2017-01-01

    Hydrogen leakage and fire ignition and propagation are safety concerns in several industrial plants. In a nuclear fusion power plants the separation of hydrogen and tritium takes place in different steps, among which one or more electrolyzers are foreseen. A fire scenario could take place in case of leakage of hydrogen. In such cases, it is important to prevent the spreading of the fire to adjacent rooms and, at the same time, to withstand the pressure load on walls, to avoid radioactivity release in the surrounding environment. A preliminary study has been carried out with the aim of comparing CFD tools for fire scenario simulations involving hydrogen release. Results have been obtained comparing two codes: ANSYS Fluent© and FDS. The two codes have been compared both for hydrogen dispersion and hydrogen fire in a confined environment. The first scenario is aimed to obtaining of volume fraction 3D maps for the evaluation of the different diffusion/transport models. In the second scenario, characterized by a double-ended guillotine break, the fire is supposed to be ignited at the same time of the impact. Simulations have been carried out for the first 60 seconds. Hydrogen concentration, temperature and pressure fields are compared and discussed.

  13. An analysis of aircraft accidents involving fires

    Science.gov (United States)

    Lucha, G. V.; Robertson, M. A.; Schooley, F. A.

    1975-01-01

    All U. S. Air Carrier accidents between 1963 and 1974 were studied to assess the extent of total personnel and aircraft damage which occurred in accidents and in accidents involving fire. Published accident reports and NTSB investigators' factual backup files were the primary sources of data. Although it was frequently not possible to assess the relative extent of fire-caused damage versus impact damage using the available data, the study established upper and lower bounds for deaths and damage due specifically to fire. In 12 years there were 122 accidents which involved airframe fires. Eighty-seven percent of the fires occurred after impact, and fuel leakage from ruptured tanks or severed lines was the most frequently cited cause. A cost analysis was performed for 300 serious accidents, including 92 serious accidents which involved fire. Personal injury costs were outside the scope of the cost analysis, but data on personnel injury judgements as well as settlements received from the CAB are included for reference.

  14. [Analysis of human tissue samples for volatile fire accelerants].

    Science.gov (United States)

    Treibs, Rudolf

    2014-01-01

    In police investigations of fires, the cause of a fire and the fire debris analysis regarding traces of fire accelerants are important aspects for forensic scientists. Established analytical procedures were recently applied to the remains of fire victims. When examining lung tissue samples, vapors inhaled from volatile ignitable liquids could be identified and differentiated from products of pyrolysis caused by the fire. In addition to the medico-legal results this evidence allowed to draw conclusions as to whether the fire victim was still alive when the fire started.

  15. Experimental determination of the shipboard fire environment for simulated radioactive material packages

    Energy Technology Data Exchange (ETDEWEB)

    Koski, J.A.; Bobbe, J.G.; Arviso, M. [and others

    1997-03-01

    A series of eight fire tests with simulated radioactive material shipping containers aboard the test ship Mayo Lykes, a break-bulk freighter, is described. The tests simulate three basic types of fires: engine room fires, cargo fires and open pool fires. Detailed results from the tests include temperatures, heat fluxes and air flows measured during the fires. The first examination of the results indicates that shipboard fires are not significantly different from fires encountered in land transport. 13 refs., 15 figs., 11 tabs.

  16. Optimized firing. Numerical simulation of flow; Optimierte Feuerung. Numerische Stroemungssimulation

    Energy Technology Data Exchange (ETDEWEB)

    Klasen, T. [Inpro-Consult (Germany); Floetgen, A.

    2007-07-01

    By the aid of a numerical flow simulation in the beginning of boiler design can be optimized geometrical and process details. An example is shown for a feeding stoker with combined dust firing of an existing boiler plant for biogenic fuels. (GL)

  17. DYNAMICS OF DETECTED FIRE FACTORS IN CLOSED COMPARTMENT: COMPUTER SIMULATION

    Directory of Open Access Journals (Sweden)

    V. V. Nevdakh

    2015-01-01

    Full Text Available Computer simulation of the initial fire stages in closed compartment with the volume of ≈ 60 m3 and with a burner on a floor and 2 m above floor have been carried using FDS software. Fires with different t 2 –power low heat release rates have been modeled. Fires which growth times to reach 1055 kW were 100 s and 500 s have been considered as fast and slow fires respectively. Dynamics of heat release rates and detected fire factors such as spatial distributions of air temperature, smoke obscuration and variations of indoor pressure have been studied. It has been obtained that dynamics of heat release rates of the initial fire stages in closed compartment consists of two stages. During the first stage the heat release rate is proportional to mass burning rate and flaming occurs only above a burner. At the second stage dynamics of heat release rates has a form of irregular in amplitude and duration pulsations, which are caused by self-ignition in the smoke layer. The compartment air volume may be layered with respect to the height and every layer has its oven temperature, smoke obscuration, self-ignition areas have been shown. The layer thickness, gradients of temperature and obscuration depend on a fire growth rate and on a burner height above floor have been concluded. The spatial distributions of air temperature and pressure variation have the opposite gradients on a height have been obtained. Maximal pressure variation and its gradient occurs under the fast fire with a burner on a floor have been obtained too. 

  18. Fire Hazards Analysis for the Inactive Equipment Storage Sprung Structure

    Energy Technology Data Exchange (ETDEWEB)

    MYOTT, C.F.

    2000-02-03

    The purpose of the analysis is to comprehensively assess the risk from fire within individual fire areas in relation to proposed fire protection so as to ascertain whether the fire protection objective of DOE Order 5480.1A are met. The order acknowledges a graded approach commensurate with the hazards involved.

  19. Simulation of evacuation behaviors in fire using spacial grid

    Institute of Scientific and Technical Information of China (English)

    YANG Lizhong; ZHAO Daoliang; LI Jian; FANG Weifeng; FAN Weicheng

    2004-01-01

    A two-dimensional Cellular Automata (CA) model to demonstrate the special phenomena of occupants evacuating from fire room is presented. A set of simple but effective models is proposed to investigate the effect of fire smoke on route choice. The concept of danger grade is introduced, and occupants select the target cell according to the value of danger grade at each time step. Some technique is introduced to substitute the human intelligence, such as premeditation. The simulation results show that human evacuation is influenced greatly by both human visual field and building exit.

  20. Thermodynamic Analysis of Supplementary-Fired Gas Turbine Cycles

    DEFF Research Database (Denmark)

    Elmegaard, Brian; Henriksen, Ulrik Birk; Qvale, Einar Bjørn

    2002-01-01

    This paper presents an analysis of the possibilities for improving the efficiency of an indirectly biomass-fired gas turbine (IBFGT) by supplementary direct gas-firing. The supplementary firing may be based on natural gas, biogas, or pyrolysis gas. {The interest in this cycle arise from a recent......: Integration between an IFGT and pyrolysis of the biofuel which will result in a highly efficient utilization of the biomass, and integration between external biomass firing, internal biomass firing and internal natural gas firing. The marginal efficiency of the natural gas is in this case found...... for the indirectly fired gas turbine (IFGT) and for the supplementary-fired IFGT. Both results show that the combination of external firing and internal firing have the potential of reducing or solving some problems with the use of biomass both in the recuperated and the indirectly fired gas turbine: The former...

  1. Modelling and simulating fire tube boiler performance

    DEFF Research Database (Denmark)

    Sørensen, K.; Condra, T.; Houbak, Niels;

    2003-01-01

    A model for a flue gas boiler covering the flue gas and the water-/steam side has been formulated. The model has been formulated as a number of sub models that are merged into an overall model for the complete boiler. Sub models have been defined for the furnace, the convection zone (split in 2......: a zone submerged in water and a zone covered by steam), a model for the material in the boiler (the steel) and 2 models for resp. the water/steam zone (the boiling) and the steam. The dynamic model has been developed as a number of Differential-Algebraic-Equation system (DAE). Subsequently Mat......Lab/Simulink has been applied for carrying out the simulations. To be able to verify the simulated results experiments has been carried out on a full scale boiler plant....

  2. Modelling and simulating fire tube boiler performance

    DEFF Research Database (Denmark)

    Sørensen, Kim; Karstensen, Claus; Condra, Thomas Joseph;

    2003-01-01

    A model for a ue gas boiler covering the ue gas and the water-/steam side has been formulated. The model has been formulated as a number of sub models that are merged into an overall model for the complete boiler. Sub models have been dened for the furnace, the convection zone (split in 2: a zone...... submerged in water and a zone covered by steam), a model for the material in the boiler (the steel) and 2 models for resp. the water/steam zone (the boiling) and the steam. The dynamic model has been developed as a number of Differential-Algebraic- Equation system (DAE). Subsequently MatLab/Simulink has...... been applied for carrying out the simulations. To be able to verify the simulated results an experiments has been carried out on a full scale boiler plant....

  3. FIRE simulations: galactic outflows and their consequences

    Science.gov (United States)

    Keres, Dusan; FIRE Team

    2016-06-01

    We study gaseous outflows and their consequences in high-resolution galaxy formation simulations with explicit stellar feedback from the Feedback in Realistic Environments project. Collective, galaxy scale, effect of stellar feedback results in episodic ejections of large amount of gas and heavy elements into the circum-galactic medium. Gas ejection episodes follow strong bursts of star formation. Properties of galactic star formation and ejection episodes depend on galaxy mass and redshift and, together with gas infall and recycling, shape the evolution of the circum-galactic medium and galaxies. As a consequence, our simulated galaxies have masses, star formation histories and heavy element content in good agreement with the observed population of galaxies.

  4. Reducing the computational requirements for simulating tunnel fires by combining multiscale modelling and multiple processor calculation

    DEFF Research Database (Denmark)

    Vermesi, Izabella; Rein, Guillermo; Colella, Francesco

    2017-01-01

    directly. The feasibility analysis showed a difference of only 2% in temperature results from the published reference work that was performed with Ansys Fluent (Colella et al., 2010). The reduction in simulation time was significantly larger when using multiscale modelling than when performing multiple......Multiscale modelling of tunnel fires that uses a coupled 3D (fire area) and 1D (the rest of the tunnel) model is seen as the solution to the numerical problem of the large domains associated with long tunnels. The present study demonstrates the feasibility of the implementation of this method...... in FDS version 6.0, a widely used fire-specific, open source CFD software. Furthermore, it compares the reduction in simulation time given by multiscale modelling with the one given by the use of multiple processor calculation. This was done using a 1200m long tunnel with a rectangular cross...

  5. Leader neurons in leaky integrate and fire neural network simulations

    OpenAIRE

    Zbinden, Cyrille

    2010-01-01

    Several experimental studies show the existence of leader neurons in population bursts of 2D living neural networks. A leader neuron is, basically, a neuron which fires at the beginning of a burst (respectively network spike) more often that we expect by looking at its whole mean neural activity. This means that leader neurons have some burst triggering power beyond a simple statistical effect. In this study, we characterize these leader neuron properties. This naturally leads us to simulate ...

  6. Time fluctuation analysis of forest fire sequences

    Science.gov (United States)

    Vega Orozco, Carmen D.; Kanevski, Mikhaïl; Tonini, Marj; Golay, Jean; Pereira, Mário J. G.

    2013-04-01

    Forest fires are complex events involving both space and time fluctuations. Understanding of their dynamics and pattern distribution is of great importance in order to improve the resource allocation and support fire management actions at local and global levels. This study aims at characterizing the temporal fluctuations of forest fire sequences observed in Portugal, which is the country that holds the largest wildfire land dataset in Europe. This research applies several exploratory data analysis measures to 302,000 forest fires occurred from 1980 to 2007. The applied clustering measures are: Morisita clustering index, fractal and multifractal dimensions (box-counting), Ripley's K-function, Allan Factor, and variography. These algorithms enable a global time structural analysis describing the degree of clustering of a point pattern and defining whether the observed events occur randomly, in clusters or in a regular pattern. The considered methods are of general importance and can be used for other spatio-temporal events (i.e. crime, epidemiology, biodiversity, geomarketing, etc.). An important contribution of this research deals with the analysis and estimation of local measures of clustering that helps understanding their temporal structure. Each measure is described and executed for the raw data (forest fires geo-database) and results are compared to reference patterns generated under the null hypothesis of randomness (Poisson processes) embedded in the same time period of the raw data. This comparison enables estimating the degree of the deviation of the real data from a Poisson process. Generalizations to functional measures of these clustering methods, taking into account the phenomena, were also applied and adapted to detect time dependences in a measured variable (i.e. burned area). The time clustering of the raw data is compared several times with the Poisson processes at different thresholds of the measured function. Then, the clustering measure value

  7. Kinematics of Galaxy Mergers in The FIRE Simulation

    Science.gov (United States)

    Flores, Jose Antonio; Moreno, Jorge

    2017-01-01

    The morphology of galaxies is a field of science still under current investigation. Today, galaxy merger simulations provide us with crucial information that plays an important role in describing the morphology of today and future galaxies. Using the Calar Alto Legacy Integral Field Area (CALIFA) survey, Barrera-Ballesteros et al. find morpho-kinematic misalignments in the stellar and ionized gas’s line of sight velocity when comparing the axis of symmetry to the axis of rotation (2015). Similarly, using the Feedback in Realistic Environment (FIRE) simulation we are able to measure stellar and ionized gas’s line of sight velocities of various galaxy mergers. The aim of this work is to determine if the observed morpho-kinematic misalignments between the axis of symmetry and axis of rotation appears in our simulations. The cause of such morpho-kinematic misalignments is yet unresolved, but by exploring various galaxy merger simulations with different properties on FIRE we plan to find a plausible explanation. This unexplained phenomenon raises awareness in determining whether current simulations match current observations and offer a better insight in understanding the morphology of galaxies.

  8. Thermodynamic Analysis of Supplementary-Fired Gas Turbine Cycles

    DEFF Research Database (Denmark)

    Elmegaard, Brian; Henriksen, Ulrik Birk; Qvale, Einar Bjørn

    2003-01-01

    This paper presents an analysis of the possibilities for improving the efficiency of an indi-rectly biomass-fired gas turbine (IBFGT) by supplementary direct gas-firing. The supple-mentary firing may be based on natural gas, biogas or pyrolysis gas. Intuitively, sup-plementary firing is expected...... for the recu-perated gas turbine. Instead, other process changes may be considered in order to obtain a high marginal efficiency on natural gas. Two possibilities are discussed: Integration between an IFGT and pyrolysis of the biofuel which will result in a highly efficient utilization of the biomass...... for the indirectly fired gas turbine (IFGT) and for the supplementary-fired IFGT. These results show that the combination of external firing and internal firing have the potential of reducing or solving some problems associated with the use of biomass both in the recuperated and the indirectly fired gas turbine...

  9. Cycle Simulation of HotWater Fired Absorption Chiller

    Science.gov (United States)

    Esaki, Shuji; Iramina, Kazuyasu; Kobayashi, Takahiro; Ohnou, Masayuki; Kaneko, Toshiyuki; Soga, Takashi

    The design limits were examined to determine the lowest temperature for hot water that can be used as a heat source to drive a hot water fired absorption chiller. Advantage was taken of the fact that the cycle calculation method using the minimum temperature difference is quite effective. This minimum temperature difference was the lower of the two temperature differences used to get the logarithmic mean temperature difference that need to design the evaporator, absorber, condenser and generator in an absorption refrigerator. This report proposes a new solution algorithm employing this minimum temperature difference to make a cycle simulation of the hot water fired absorption chiller. It shows the lowest usable temperature for hot water and makes clear the chilled water and cooling water temperature conditions that can provide the lowest temperature.

  10. Fire simulation of the canister transfer and installation vehicle; Kapselin siirto- ja asennusajoneuvon palosimulointi

    Energy Technology Data Exchange (ETDEWEB)

    Peltokorpi, L. [Fortum Power and Heat Oy, Espoo (Finland)

    2012-12-15

    A pyrolysis model of the canister transfer and installation vehicle was developed and vehicle fires in the final disposal tunnel and in the central tunnel were simulated using the fire simulation program FDS (Fire Dynamics Simulator). For comparison, same vehicle fire was also simulated at conditions in which the fire remained as a fuel controlled during the whole simulation. The purpose of the fire simulations was to simulate the fire behaviour realistically taking into account for example the limitations coming from the lack of oxygen. The material parameters for the rubber were defined and the simulation models for the tyres developed by simulating the fire test of a front wheel loader rubber tyre done by SP Technical Research Institute of Sweden. In these simulations the most important phenomena were successfully brought out but the timing of the phenomena was difficult. The final values for the rubber material parameters were chosen so that the simulated fire behaviour was at least as intense as the measured one. In the vehicle fire simulations a hydraulic oil or diesel leak causing a pool fire size of 2 MW and 2 m{sup 2} was assumed. The pool fire was assumed to be located under the tyres of the SPMT (Self Propelled Modular Transporters) transporter. In each of the vehicle fire simulations only the tyres of the SPMT transporter were observed to be burning whereas the tyres of the trailer remained untouched. In the fuel controlled fire the maximum power was slightly under 10 MW which was reached in about 18 minutes. In the final disposal tunnel the growth of the fire was limited due to the lack of oxygen and the relatively fast air flows existing in the tunnel. Fast air flows caused the flame spreading to be limited to the certain directions. In the final disposal tunnel fire the maximum power was slightly over 7 MW which was reached about 8 minutes after the ignition. In the central tunnel there was no shortage of oxygen but the spread of the fire was limited

  11. Simulation of Quaking Aspen Potential Fire Behavior in Northern Utah, USA

    Directory of Open Access Journals (Sweden)

    R. Justin DeRose

    2014-12-01

    Full Text Available Current understanding of aspen fire ecology in western North America includes the paradoxical characterization that aspen-dominated stands, although often regenerated following fire, are “fire-proof”. We tested this idea by predicting potential fire behavior across a gradient of aspen dominance in northern Utah using the Forest Vegetation Simulator and the Fire and Fuels Extension. The wind speeds necessary for crowning (crown-to-crown fire spread and torching (surface to crown fire spread were evaluated to test the hypothesis that predicted fire behavior is influenced by the proportion of aspen in the stand. Results showed a strong effect of species composition on crowning, but only under moderate fire weather, where aspen-dominated stands were unlikely to crown or torch. Although rarely observed in actual fires, conifer-dominated stands were likely to crown but not to torch, an example of “hysteresis” in crown fire behavior. Results support the hypothesis that potential crown fire behavior varies across a gradient of aspen dominance and fire weather, where it was likely under extreme and severe fire weather, and unlikely under moderate and high fire weather. Furthermore, the “fire-proof” nature of aspen stands broke down across the gradient of aspen dominance and fire weather.

  12. Phase 2 fire hazard analysis for the canister storage building

    Energy Technology Data Exchange (ETDEWEB)

    Sadanaga, C.T., Westinghouse Hanford

    1996-07-01

    The fire hazard analysis assesses the risk from fire in a facility to ascertain whether the fire protection policies are met. This document provides a preliminary FHA for the CSB facility. Open items have been noted in the document. A final FHA will be required at the completion of definitive design, prior to operation of the facility.

  13. The analysis of fire losses and characteristics of residential fires based on investigation data in Selangor, 2012-2014

    OpenAIRE

    Tan Yi Rong; Akashah Farid Wajdi; Mahyuddin Norhayati

    2016-01-01

    This is a research in progress where authors seek to investigate the factors of residential fires. As part of the research, this paper aims to analyse the fire problems faced by the community of Malaysia. Data regarding residential fires between 2012 and 2014 was collected from fire investigation reports prepared by the Selangor Fire and Rescue Department. Descriptive analysis is conducted to summarize the data collected and describe the common phenomenon of residential fires. The distributio...

  14. Use of numerical simulation computer codes to fire problems in nuclear power plants in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Keski-Rahkonen, O.; Eloranta, E. (Valtion Teknillinen Tutkimuskeskus, Espoo (Finland). Fire Technology Lab.); Huhtanen, R. (Valtion Teknillinen Tutkimuskeskus, Helsinki (Finland). Nuclear Engineering Lab.)

    1991-03-01

    Zone and field model codes are used for fire simulations, including nuclear facilities, in Finland. Here two examples are described: (a) calculation of evaporation rate of a pool fire (8 MW) in a compartment using FIRST, and calculation of an oil spill fire (180 MW) in a turbine hall using PHOENICS. (orig.).

  15. 49 CFR Appendix B to Part 179 - Procedures for Simulated Pool and Torch-Fire Testing

    Science.gov (United States)

    2010-10-01

    ... used to simulate a torch fire under paragraph 3a(2) of this appendix. (2) The back of the bare plate... 49 Transportation 2 2010-10-01 2010-10-01 false Procedures for Simulated Pool and Torch-Fire... SPECIFICATIONS FOR TANK CARS Pt. 179, App. B Appendix B to Part 179—Procedures for Simulated Pool and...

  16. “Use of fire extinguishers”—a new course with a new simulator

    CERN Multimedia

    HSE Unit & GS/FB

    2012-01-01

    Don’t wait, sign up! A new training course, “Handling of fire extinguishers”, is available since the beginning of March 2012. The training course is given by members of CERN’s Fire Brigade (GS-FB) and is intended for all members of personnel of CERN. Upon successful completion of the training course, you will be able to do the following: recognise a potentially combustible item and the various fire classes; choose the appropriate extinguisher for a given fire class; handle a fire extinguisher properly and efficiently; apply CERN's safety instructions. An important part of the training are the different firefighting exercises conducted using a new simulator, which makes it possible to simulate real conditions such as the following: a fire in the office; a fire in an electrical cabinet; a fire involving chemicals.        Don’t wait:  sign up for the training course directly ...

  17. Fire hazards analysis for W030 tank farm ventilation upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Huckfeldt, R.A.

    1996-07-17

    This Fire Hazard Analysis (FHA) was prepared according to the requirements of U.S. Department of Energy (DOE) Order 5480.7A,FIRE PROTECTION, 2-17-93. The purpose of this FHA is to ascertain whether the objectives of DOE 5480.7A are being met. This purpose is accomplished through a conservative comprehensive assessment of the risk from fire and other perils within individual fire areas of a DOE facility in relation to proposed fire protection. This FHA is based on conditions set forth within this document and is valid only under these conditions.

  18. Virtual Reality Simulation of Fire Fighting Robot Dynamic and Motion

    CERN Document Server

    Setiawan, Joga D; Budiyono, Agus

    2008-01-01

    This paper presents one approach in designing a Fire Fighting Robot which has been contested annually in a robotic student competition in many countries following the rules initiated at the Trinity College. The approach makes use of computer simulation and animation in a virtual reality environment. In the simulation, the amount of time, starting from home until the flame is destroyed, can be confirmed. The efficacy of algorithms and parameter values employed can be easily evaluated. Rather than spending time building the real robot in a trial and error fashion, now students can explore more variation of algorithm, parameter and sensor-actuator configuration in the early stage of design. Besides providing additional excitement during learning process and enhancing students understanding to the engineering aspects of the design, this approach could become a useful tool to increase the chance of winning the contest.

  19. Advanced analysis and design for fire safety of steel structures

    CERN Document Server

    Li, Guoqiang

    2013-01-01

    Advanced Analysis and Design for Fire Safety of Steel Structures systematically presents the latest findings on behaviours of steel structural components in a fire, such as the catenary actions of restrained steel beams, the design methods for restrained steel columns, and the membrane actions of concrete floor slabs with steel decks. Using a systematic description of structural fire safety engineering principles, the authors illustrate the important difference between behaviours of an isolated structural element and the restrained component in a complete structure under fire conditions. The book will be an essential resource for structural engineers who wish to improve their understanding of steel buildings exposed to fires. It is also an ideal textbook for introductory courses in fire safety for master’s degree programs in structural engineering, and is excellent reading material for final-year undergraduate students in civil engineering and fire safety engineering. Furthermore, it successfully bridges th...

  20. Fire case of brick-wood structural lodging with plastic top and numerical simulation analysis%简易塑料顶棚砖木结构出租房火灾调查

    Institute of Scientific and Technical Information of China (English)

    张小芹; 刘涛

    2011-01-01

    介绍了一起带简易塑料顶棚砖木结构出租房火灾的调查走访和现场勘验过程,总结调查工作的成功经验.利用FDS还原火灾事故的过程.结果显示,塑料顶棚大大加快了室内火灾的发展蔓延,室内人员的有效逃生时间缩短2/3以上,很大程度上增加了室内火灾危险性.%This paper described the on-scene interrogation and fire scene proccssing of a brick-wood structural lodging with plastic top fire cast detailedly, and successful experiences were summairized. Numerical simulation technology was Applied to this fire investigation and reconstructed the process of fire accident. It indicated that plastic top greatly accelerated the development and oversprcad of indoor fire. and shartened two-part of the effectual fleeing time for indoor people, and increased the fire fatalness deeply.

  1. Hazard Analysis on One—Room Building Fires

    Institute of Scientific and Technical Information of China (English)

    YuDeming; FengChanggen

    1998-01-01

    First,a calculation method for available safety egress time (shortly called ASET) and requirement safety egress time (Shortly called RSET) in a one-room building fire is proposed and a model for predicting the death number caused by the fire is established in this paper,Then,numerical simulations are performed,and the following laws are discovered:(1)At the beginning of the fire,the smoke layer falls slowly;as the fire develops,it falls rapidly.(2) The hypotheses on the fire source,the combustion properties of the combustibles,and the width of the exit and the person number in the room are important factors which affect the death number in the fire.

  2. 327 Building fire hazards analysis implementation plan

    Energy Technology Data Exchange (ETDEWEB)

    Eggen, C.D.

    1998-09-16

    In March 1998, the 327 Building Fire Hazards Analysis (FRA) (Reference 1) was approved by the US Department of Energy, Richland Operations Office (DOE-RL) for implementation by B and W Hanford Company (B and WHC). The purpose of the FHA was to identify gaps in compliance with DOE Order 5480.7A (Reference 2) and Richland Operations Office Implementation Directive (RLID) 5480.7 (Reference 3), especially in regard to loss limitation. The FHA identified compliance gaps in five areas and provided nine recommendations (11 items) to bring the 327 Building into compliance. To date, actions for five of the 11 items have been completed. Exemption requests will be transmitted to DOE-RL for two of the items. Corrective actions have been identified for the remaining four items. The completed actions address combustible loading requirements associated with the operation of the cells and support areas. The status of the recommendations and actions was confirmed during the July 1998 Fire Protection Assessment. B and WHC will use this Implementation Plan to bring the 327 Building and its operation into compliance with DOE Order 5480.7A and RLID 5480.7.

  3. The analysis of fire losses and characteristics of residential fires based on investigation data in Selangor, 2012-2014

    Directory of Open Access Journals (Sweden)

    Tan Yi Rong

    2016-01-01

    Full Text Available This is a research in progress where authors seek to investigate the factors of residential fires. As part of the research, this paper aims to analyse the fire problems faced by the community of Malaysia. Data regarding residential fires between 2012 and 2014 was collected from fire investigation reports prepared by the Selangor Fire and Rescue Department. Descriptive analysis is conducted to summarize the data collected and describe the common phenomenon of residential fires. The distributions of the fire characteristics suggested that residential fires are commonly occurred during daytime, confined within the room of fire origin, caused by electrical failure and cooking negligence, started from kitchen, and occurred in multi-units housing. Further analysis will be conducted in order to investigate the relationships between the characteristics and residential fires.

  4. Comparison of serial and parallel simulations of a corridor fire using FDS

    Science.gov (United States)

    Valasek, L.

    2015-09-01

    Current fire simulators allow to model the course of fire in large areas and its impact on structure and equipment. This paper deals with a comparison of serial and parallel calculations of simulation of a corridor fire by the FDS (Fire Dynamics Simulator) system. In parallel case, the whole computational domain is divided into several computational meshes, the computation on each mesh is considered as a single MPI (Message Passing Interface) process realised on one computational core and communication between MPI processes is provided by MPI. The aim of this paper is to determine the size of error caused by parallelization of computation, which occurs at touches of computational meshes.

  5. The application of super wavelet finite element on temperature-pressure coupled field simulation of LPG tank under jet fire

    Science.gov (United States)

    Zhao, Bin

    2015-02-01

    Temperature-pressure coupled field analysis of liquefied petroleum gas (LPG) tank under jet fire can offer theoretical guidance for preventing the fire accidents of LPG tank, the application of super wavelet finite element on it is studied in depth. First, review of related researches on heat transfer analysis of LPG tank under fire and super wavelet are carried out. Second, basic theory of super wavelet transform is studied. Third, the temperature-pressure coupled model of gas phase and liquid LPG under jet fire is established based on the equation of state, the VOF model and the RNG k-ɛ model. Then the super wavelet finite element formulation is constructed using the super wavelet scale function as interpolating function. Finally, the simulation is carried out, and results show that the super wavelet finite element method has higher computing precision than wavelet finite element method.

  6. Validation and uncertainty quantification of Fuego simulations of calorimeter heating in a wind-driven hydrocarbon pool fire.

    Energy Technology Data Exchange (ETDEWEB)

    Domino, Stefan Paul; Figueroa, Victor G.; Romero, Vicente Jose; Glaze, David Jason; Sherman, Martin P.; Luketa-Hanlin, Anay Josephine

    2009-12-01

    The objective of this work is to perform an uncertainty quantification (UQ) and model validation analysis of simulations of tests in the cross-wind test facility (XTF) at Sandia National Laboratories. In these tests, a calorimeter was subjected to a fire and the thermal response was measured via thermocouples. The UQ and validation analysis pertains to the experimental and predicted thermal response of the calorimeter. The calculations were performed using Sierra/Fuego/Syrinx/Calore, an Advanced Simulation and Computing (ASC) code capable of predicting object thermal response to a fire environment. Based on the validation results at eight diversely representative TC locations on the calorimeter the predicted calorimeter temperatures effectively bound the experimental temperatures. This post-validates Sandia's first integrated use of fire modeling with thermal response modeling and associated uncertainty estimates in an abnormal-thermal QMU analysis.

  7. Simulation and Analysis of Cement Clinker Subsection Firing%水泥熟料分段烧成模拟分析

    Institute of Scientific and Technical Information of China (English)

    封培然; 邢文杰; 齐砚勇

    2011-01-01

    By establishing the calculation of the mathematical model of NSP cement rotary kiln burning zone temperature ( BZT), this paper computed two types of different cement kiln BZT, analyzed two types of different kiln temperature distribution, then put forward the idealized burn clinker piecewise model. The study shows that short kiln in transitional zone has ordinary kiln type temperature gradient approximately 8 times, but in the burning zone both almost have no temperature change and subsection firing still have 15℃ heats up. Therefore subsection firing a has good clinker reaction temperature environment, which is beneficial to improving the quality of clinker.%通过建立新型干法水泥回转窑烧成带温度计算的数学模型,计算出两种不同水泥窑型的烧成带温度,分析了两种不同窑型的温度分布,进而提出熟料分段烧成的理想化模型。研究发现:短窑在过渡带具有普通窑型约8倍的温度梯度,但是在烧成带两者几乎没有温度变化,而分段烧成依然有15℃的升温,因此分段烧成具有良好的熟料反应温度环境,有利于熟料质量的提高。

  8. Spontaneous combustion and simulation of mine fires and their effects on mine ventilation systems

    Energy Technology Data Exchange (ETDEWEB)

    Gillies, A.D.S.; Wu, H.W.; Humphreys, D. [Gillies Wu Mining Technology Pty Ltd, Taringa, Qld (Australia). The Minserve Group

    2005-07-01

    The structure of a comprehensive research project into mine fires study applying the Ventgraph mine fire simulation software, preplanning of escape scenarios and general interaction with rescue responses is outlined. The project has Australian Coal Association Research Program (ACARP) funding and also relies on substantial mining company site support. This practical input from mine operators is essential and allows the approach to be introduced in the most creditable way. The effort is built around the introduction of fire simulation computer software to the Australian mining industry and the consequent modelling of fire scenarios in selected different mine layouts. The primary objective of the part of the study described in this paper is to use mine fire simulation software to gain better understanding of how spontaneous combustion initiated fires can interact with the complex ventilation behaviour underground during a substantial fire. It focuses on the simulation of spontaneous combustion sourced heatings that develop into open fires. Further, it examines ventilation behaviour effects of spontaneous combustion initiated pillar fires and examines the difficulties these can be present if a ventilation reversal occurs. It also briefly examines simulation of use of the inertisation to assist in mine recovery. 16 refs., 13 figs., 1 tab.

  9. Simulation of wind-driven dispersion of fire pollutants in a street canyon using FDS.

    Science.gov (United States)

    Pesic, Dusica J; Blagojevic, Milan Dj; Zivkovic, Nenad V

    2014-01-01

    Air quality in urban areas attracts great attention due to increasing pollutant emissions and their negative effects on human health and environment. Numerous studies, such as those by Mouilleau and Champassith (J Loss Prevent Proc 22(3): 316-323, 2009), Xie et al. (J Hydrodyn 21(1): 108-117, 2009), and Yassin (Environ Sci Pollut Res 20(6): 3975-3988, 2013) focus on the air pollutant dispersion with no buoyancy effect or weak buoyancy effect. A few studies, such as those by Hu et al. (J Hazard Mater 166(1): 394-406, 2009; J Hazard Mater 192(3): 940-948, 2011; J Civ Eng Manag (2013)) focus on the fire-induced dispersion of pollutants with heat buoyancy release rate in the range from 0.5 to 20 MW. However, the air pollution source might very often be concentrated and intensive, as a consequence of the hazardous materials fire. Namely, transportation of fuel through urban areas occurs regularly, because it is often impossible to find alternative supply routes. It is accompanied with the risk of fire accident occurrences. Accident prevention strategies require analysis of the worst scenarios in which fire products jeopardize the exposed population and environment. The aim of this article is to analyze the impact of wind flow on air pollution and human vulnerability to fire products in a street canyon. For simulation of the gasoline tanker truck fire as a result of a multivehicle accident, computational fluid dynamics large eddy simulation method has been used. Numerical results show that the fire products flow vertically upward, without touching the walls of the buildings in the absence of wind. However, when the wind velocity reaches the critical value, the products touch the walls of the buildings on both sides of the street canyon. The concentrations of carbon monoxide and soot decrease, whereas carbon dioxide concentration increases with the rise of height above the street canyon ground level. The longitudinal concentration of the pollutants inside the street

  10. Dynamics analysis on neural firing patterns by symbolic approach

    Institute of Scientific and Technical Information of China (English)

    Gao Zhi-Ying; Lu Qi-Shao

    2007-01-01

    Neural firing patterns are investigated by using symbolic dynamics. Bifurcation behaviour of the Hindmarsh-Rose (HR) neuronal model is simulated with the external stimuli gradually decreasing, and various firing activities with different topological structures are orderly numbered. Through constructing first-return maps of interspike intervals, all firing patterns are described and identified by symbolic expressions. On the basis of ordering rules of symbolic sequences, the corresponding relation between parameters and firing patterns is established, which will be helpful for encoding neural information. Moreover, using the operation rule of * product, generation mechanisms and intrinsic configurations of periodic patterns can be distinguished in detail. Results show that the symbolic approach is a powerful tool to study neural firing activities. In particular, such a coarse-grained way can be generalized in neural electrophysiological experiments to extract much valuable information from complicated experimental data.

  11. Fire emissions simulated by prescribing burned area observations in a global vegetation model

    Science.gov (United States)

    Khlystova, Iryna G.; Wilkenskjeld, Stiig; Kloster, Silvia

    2014-05-01

    The emissions of trace gases and aerosols from large vegetation fires into the atmosphere have an important climate impact. In this study we integrate observed burned area into a global vegetation model to derive global fire emissions. A global continuous burned area products provided by GFED (Global Fire Emissions Dataset) were obtained from MODIS (and pre-MODIS) satellites and are available for the time period 1997-2011. We integrate the global burned area product into the global vegetation model JSBACH, a land part of the Earth-System model developed at the Max Planck Institute for Meteorology. JSBACH simulates land biomass in terms of carbon, which can be combined with the satellite burned area information to derive fire carbon emissions. Some assumptions on fire fuel consumptions have to be made during the integration of satellite burned area into the JSBACH. This includes processes such as tree mortality and combustion completeness, i.e. how much of the vegetation biomass gets combusted during a fire. Partially, this information can be also obtained from measurements. In this study we follow closely the approach of GFED, incorporating also GFED supplemental information, to simulate fuel consumption in JSBACH. And we compare simulated by this approach fire carbon emissions with the fire emissions from GFED. Global vegetation models often use prescribed land cover maps. The simulated in the JSBACH vegetation biomass and thus the simulated fire carbon emissions critically depend on the land cover distribution. In our study we derive fire carbon emissions using two different land cover parameterizations, based on two different satellite datasets. We will present the results obtained from simulations using the JSBACH standard MODIS based vegetation distribution and compare them to the results derived using the recently released ESA CCI land cover satellite product to demonstrate the sensitivity of simulated fire carbon emissions to the underlying land cover

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

    Science.gov (United States)

    Kloster, Silvia; Lasslop, Gitta

    2017-03-01

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

  13. Nonlinear phased analysis of reinforced concrete tunnels under fire exposure

    NARCIS (Netherlands)

    Lilliu, G.; Meda, A.

    2013-01-01

    Fire analysis of precast segmental tunnels involves several problems, mainly related to the soil-structure interaction during fire exposure, coupled with material degradation. Temperature increase in the tunnel is the cause of thermal expansion of the lining, which is resisted by the soil pressure.

  14. FIRE in the Field: Simulating the Threshold of Galaxy Formation

    CERN Document Server

    Fitts, Alex; Elbert, Oliver D; Bullock, James S; Hopkins, Philip F; Onorbe, Jose; Wetzel, Andrew R; Wheeler, Coral; Faucher-Giguere, Claude-Andre; Keres, Dusan; Skillman, Evan D; Weisz, Daniel R

    2016-01-01

    We present a suite of 15 cosmological zoom-in simulations of isolated dark matter halos, all with masses of $M_{\\rm halo} \\approx 10^{10}\\,{\\rm M}_\\odot$ at $z=0$, in order to understand the relationship between halo assembly, galaxy formation, and feedback's effects on the central density structure in dwarf galaxies. These simulations are part of the Feedback in Realistic Environments (FIRE) project and are performed at extremely high resolution. The resultant galaxies have stellar masses that are consistent with rough abundance matching estimates, coinciding with the faintest galaxies that can be seen beyond the virial radius of the Milky Way ($M_\\star/{\\rm M}_\\odot\\approx 10^5-10^7$). This non-negligible spread in stellar mass at $z=0$ in halos within a narrow range of virial masses is strongly correlated with central halo density or maximum circular velocity $V_{\\rm max}$. Much of this dependence of $M_\\star$ on a second parameter (beyond $M_{\\rm halo}$) is a direct consequence of the $M_{\\rm halo}\\sim10^...

  15. Fire Risk Analysis and Optimization of Fire Prevention Management for Green Building Design and High Rise Buildings: Hong Kong Experience

    Directory of Open Access Journals (Sweden)

    Yau Albert

    2014-12-01

    Full Text Available There are many iconic high rise buildings in Hong Kong, for example, International Commercial Centre, International Financial Centre, etc. Fire safety issue in high rise buildings has been raised by local fire professionals in terms of occupant evacuation, means of fire-fighting by fire fighters, sprinkler systems to automatically put off fires in buildings, etc. Fire risk becomes an important issue in building fire safety because it relates to life safety of building occupants where they live and work in high rise buildings in Hong Kong. The aim of this research is to identify the fire risk for different types of high rise buildings in Hong Kong and to optimise the fire prevention management for those high rise buildings with higher level of fire risk and to validate the model and also to carry out the study of the conflict between the current fire safety building code and the current trend of green building design. Survey via the 7-point scale questionnaire was conducted through 50 participants and their responses were received and analysed via the statistical tool SPSS software computer program. A number of statistical methods of testing for significantly difference in samples were adopted to carry out the analysis of the data received. When the statistical analysis was completed, the results of the data analysis were validated by two Fire Safety Experts in this area of specialisation and also by quantitative fire risk analysis.

  16. Simulation of Intelligent Fire Detection and Alarm System for a W d p .

    Directory of Open Access Journals (Sweden)

    V. B. Pati

    1989-01-01

    Full Text Available Fire is one of the major hazards in warships. A warship being avery complex structure, with sophisticated weapons, machinery, fueland ammunition is always at risk of fire. Restrictions on movement of ship's personnel and equipment requires automation in fire detectionand control systems. This paper describes the limitations of conventional fire detection systems, followed by the features of modern fire detection and alarnr (the so-called intelligent systems and thetypes of fire detectors used in fire detection systems. The experimentalset-up used for simulating a simple system having 24 sensors connecteato the micro computer via digital input card is explained in detail withthe limitations of the experimental set-up and improvements that canbe made by incorporating serial communication in a loop, using fibre optics data links. and intelligent loop/interface units.

  17. Analysis of weather condition influencing fire regime in Italy

    Science.gov (United States)

    Bacciu, Valentina; Masala, Francesco; Salis, Michele; Sirca, Costantino; Spano, Donatella

    2014-05-01

    Fires have a crucial role within Mediterranean ecosystems, with both negative and positive impacts on all biosphere components and with reverberations on different scales. Fire determines the landscape structure and plant composition, but it is also the cause of enormous economic and ecological damages, beside the loss of human life. In addition, several authors are in agreement suggesting that, during the past decades, changes on fire patterns have occurred, especially in terms of fire-prone areas expansion and fire season lengthening. Climate and weather are two of the main controlling agents, directly and indirectly, of fire regime influencing vegetation productivity, causing water stress, igniting fires through lightning, or modulating fire behavior through wind. On the other hand, these relationships could be not warranted in areas where most ignitions are caused by people (Moreno et al. 2009). Specific analyses of the driving forces of fire regime across countries and scales are thus still required in order to better anticipate fire seasons and also to advance our knowledge of future fire regimes. The objective of this work was to improve our knowledge of the relative effects of several weather variables on forest fires in Italy for the period 1985-2008. Meteorological data were obtained through the MARS (Monitoring Agricultural Resources) database, interpolated at 25x25 km scale. Fire data were provided by the JRC (Join Research Center) and the CFVA (Corpo Forestale e di Vigilanza Ambientale, Sardinia). A hierarchical cluster analysis, based on fire and weather data, allowed the identification of six homogeneous areas in terms of fire occurrence and climate (pyro-climatic areas). Two statistical techniques (linear and non-parametric models) were applied in order to assess if inter-annual variability in weather pattern and fire events had a significant trend. Then, through correlation analysis and multi-linear regression modeling, we investigated the

  18. Numerical simulation and analysis of fire protection design of a hanging dome theater%某悬挂式球幕影院消防设计数值模拟分析

    Institute of Scientific and Technical Information of China (English)

    赵泽文; 徐海斌

    2011-01-01

    Fire water cannon system was set at the screen area which connected the upper and lower in a hanging dome theater. According to the distribution of combustible in each functional areas and the setting of fire safety facilities, the fire of mechanical seats in spacecraft viewing area have been simulated in different fire scenarios. The results showed that: ASET was affected mainly by the visibility. Mechanical exhaust system is more important than automatic sprinkler system in such building. Even if the automatic sprinkler system and the exhaust system are mechanical failure, fire will not spread by way of thermal radiation. Screen area which connected the upper and lower in such building can be divided into one fire compartment in the case of decorating by non-flammable materials.%某悬挂式球幕影院建筑上下连通的荧幕区设置消防水炮系统.根据各功能区可燃物分布和消防设施设置情况,针对飞船观看区发生机械座椅火灾设置不同火灾场景进行数值模拟分析,结果表明:人员可用疏散时间主要受能见度影响;此类建筑中机械排烟系统重要性大于自动喷水灭火系统;即使自动喷水灭火系统于机械排烟系统均失效,火灾也不会通过热辐射的方式蔓延;在确保装修材料为不燃性材料的情况下,此类建筑上下连通的荧幕区可划分为同一防火分区.

  19. Material Analysis for a Fire Assessment.

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Alexander; Nemer, Martin B.

    2014-08-01

    This report consolidates technical information on several materials and material classes for a fire assessment. The materials include three polymeric materials, wood, and hydraulic oil. The polymers are polystyrene, polyurethane, and melamine- formaldehyde foams. Samples of two of the specific materials were tested for their behavior in a fire - like environment. Test data and the methods used to test the materials are presented. Much of the remaining data are taken from a literature survey. This report serves as a reference source of properties necessary to predict the behavior of these materials in a fire.

  20. Boolean algebraic analysis of fire protection

    Energy Technology Data Exchange (ETDEWEB)

    Hulme, B.L.; Shiver, A.W.; Slater, P.J.

    1982-01-01

    This paper describes a computational procedure which can be used to find minimum cost ways to protect the critical combinations of equipment from a single-source fire by protecting certain areas and strengthening certain barriers against fire. The procedure yields a complete set of optimum solutions by iteratively computing upper and lower bounds on the minimum cost. The fire protection sets evolve from Boolean algebraic computations which obtain minimum cost blocking sets associated with the lower bounds while the upper bounds are producd by maxflow-mincut calculations in a network.

  1. Numerical simulation methods of fires in nuclear power plants; Ydinvoimalaitosten tulipalojen laskentamenetelmaet

    Energy Technology Data Exchange (ETDEWEB)

    Keski-Rahkonen, O.; Bjoerkman, J.; Heikkilae, L. [Technical Research Centre of Finland, Espoo (Finland). Fire Technology Lab.

    1992-12-31

    Fire is a significant hazard to the safety of nuclear power plants (NPP). Fire may be serious accident as such, but even small fire at a critical point in a NPP may cause an accident much more serious than fire itself. According to risk assessments a fire may be an initial cause or a contributing factor in a large part of reactor accidents. At the Fire Technology and the the Nuclear Engineering Laboratory of the Technical Research Centre of Finland (VTT) fire safety research for NPPs has been carried out in a large extent since 1985. During years 1988-92 a project Advanced Numerical Modelling in Nuclear Power Plants (PALOME) was carried out. In the project the level of numerical modelling for fire research in Finland was improved by acquiring, preparing for use and developing numerical fire simulation programs. Large scale test data of the German experimental program (PHDR Sicherheitsprogramm in Kernforschungscentral Karlsruhe) has been as reference. The large scale tests were simulated by numerical codes and results were compared to calculations carried out by others. Scientific interaction with outstanding foreign laboratories and scientists has been an important part of the project. This report describes the work of PALOME-project carried out at the Fire Technology Laboratory only. A report on the work at the Nuclear Engineering Laboratory will be published separatively. (au).

  2. Simulating Changes in Fires and Ecology of the 21st Century Eurasian Boreal Forests of Siberia

    Directory of Open Access Journals (Sweden)

    Ksenia Brazhnik

    2017-02-01

    Full Text Available Wildfires release the greatest amount of carbon into the atmosphere compared to other forest disturbances. To understand how current and potential future fire regimes may affect the role of the Eurasian boreal forest in the global carbon cycle, we employed a new, spatially-explicit fire module DISTURB-F (DISTURBance-Fire in tandem with a spatially-explicit, individually-based gap dynamics model SIBBORK (SIBerian BOReal forest simulator calibrated to Krasnoyarsk Region. DISTURB-F simulates the effect of forest fire on the boreal ecosystem, namely the mortality of all or only the susceptible trees (loss of biomass, i.e., carbon within the forested landscape. The fire module captures some important feedbacks between climate, fire and vegetation structure. We investigated the potential climate-driven changes in the fire regime and vegetation in middle and south taiga in central Siberia, a region with extensive boreal forest and rapidly changing climate. The output from this coupled simulation can be used to estimate carbon losses from the ecosystem as a result of fires of different sizes and intensities over the course of secondary succession (decades to centuries. Furthermore, it may be used to assess the post-fire carbon storage capacity of potential future forests, the structure and composition of which may differ significantly from current Eurasian boreal forests due to regeneration under a different climate.

  3. Gusty, gaseous flows of FIRE: galactic winds in cosmological simulations with explicit stellar feedback

    CERN Document Server

    Muratov, Alexander L; Faucher-Giguere, Claude-Andre; Hopkins, Philip F; Quataert, Eliot; Murray, Norman

    2015-01-01

    We present an analysis of the galaxy-scale gaseous outflows from the FIRE (Feedback in Realistic Environments) simulations. This suite of hydrodynamic cosmological zoom simulations provides a sample of halos where star-forming giant molecular clouds are resolved to z=0, and features an explicit stellar feedback model on small scales. In this work, we focus on quantifying the gas mass ejected out of galaxies in winds and how this material travels through the halo. We correlate these quantities to star formation in galaxies throughout cosmic history. Our simulations reveal that a significant portion of every galaxy's evolution, particularly at high redshift, is dominated by bursts of star formation, which are followed by powerful gusts of galactic outflow that sweep up a large fraction of gas in the interstellar medium and send it through the circumgalactic medium. The dynamical effect of these outflows can significantly limit the amount of star formation within the affected galaxy. At low redshift, however, su...

  4. Cable Hot Shorts and Circuit Analysis in Fire Risk Assessment

    Energy Technology Data Exchange (ETDEWEB)

    LaChance, Jeffrey; Nowlen, Steven P.; Wyant, Frank

    1999-05-19

    Under existing methods of probabilistic risk assessment (PRA), the analysis of fire-induced circuit faults has typically been conducted on a simplistic basis. In particular, those hot-short methodologies that have been applied remain controversial in regards to the scope of the assessments, the underlying methods, and the assumptions employed. To address weaknesses in fire PRA methodologies, the USNRC has initiated a fire risk analysis research program that includes a task for improving the tools for performing circuit analysis. The objective of this task is to obtain a better understanding of the mechanisms linking fire-induced cable damage to potentially risk-significant failure modes of power, control, and instrumentation cables. This paper discusses the current status of the circuit analysis task.

  5. CFD simulation of coal and straw co-firing

    DEFF Research Database (Denmark)

    Junker, Helle; Hvid, Søren L.; Larsen, Ejvind;

    This paper presents the results of a major R&D program with the objective to develop CFD based tools to assess the impact of biomass co-firing in suspension fired pulverized coal power plants. The models have been developed through a series of Danish research projects with the overall objective t...

  6. Energy Analysis of a Biomass Co-firing Based Pulverized Coal Power Generation System

    Directory of Open Access Journals (Sweden)

    Marc A. Rosen

    2012-03-01

    Full Text Available The results are reported of an energy analysis of a biomass/coal co-firing based power generation system, carried out to investigate the impacts of biomass co-firing on system performance. The power generation system is a typical pulverized coal-fired steam cycle unit, in which four biomass fuels (rice husk, pine sawdust, chicken litter, and refuse derived fuel and two coals (bituminous coal and lignite are considered. Key system performance parameters are evaluated for various fuel combinations and co-firing ratios, using a system model and numerical simulation. The results indicate that plant energy efficiency decreases with increase of biomass proportion in the fuel mixture, and that the extent of the decrease depends on specific properties of the coal and biomass types.

  7. Cutting costs through detailed probabilistic fire risk analysis

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Luiz; Huser, Asmund; Vianna, Savio [Det Norske Veritas PRINCIPIA, Rio de Janeiro, RJ (Brazil)

    2004-07-01

    A new procedure for calculation of fire risks to offshore installations has been developed. The purposes of the procedure are to calculate the escalation and impairment frequencies to be applied in quantitative risk analyses, to optimize Passive Fire Protection (PFP) arrangement, and to optimize other fire mitigation means. The novelties of the procedure are that it uses state of the art Computational Fluid Dynamics (CFD) models to simulate fires and radiation, as well as the use of a probabilistic approach to decide the dimensioning fire loads. A CFD model of an actual platform was used to investigate the dynamic properties of a large set of jet fires, resulting in detailed knowledge of the important parameters that decide the severity of offshore fires. These results are applied to design the procedure. Potential increase in safety is further obtained for those conditions where simplified tools may have failed to predict abnormal heat loads due to geometrical effects. Using a field example it is indicated that the probabilistic approach can give significant reductions in PFP coverage with corresponding cost savings, still keeping the risk at acceptable level. (author)

  8. Fire analysis for compartment of ITER tritium SDS

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Woo Seok; Bang, Kyoung Sik [KAERI, Daejeon (Korea, Republic of); Cho, Seung Yon; Yun, Sei Hun [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2012-10-15

    The objective of the fire accident analysis for the compartment where the ITER tritium storage and delivery system (hereafter SDS) glove boxes are installed is to estimate the integrity of the glove box. Fires in grouped electrical cable trays pose distinct fire hazards within the compartment where the SDS glove boxes are installed. The nuclear industry has defined two general types of electrical cables, referred to as IEEE 383 qualified and unqualified. According to NUREG/CR 4679 and DOT TSC UMAT 83 4 1, a damage threshold temperature of 370 .deg. C and a critical heat flux of 10 kW/m2 have been selected for IEEE 383 qualified cable. A damage threshold temperature of 218 .deg. C and a critical heat flux of 5 kW/m2 have been selected for IEEE 383 unqualified cable. Cable tray fires can occur from various sources. The scenarios of concern include a fire within a cable tray and as exposure fire. However, fire within the compartment where the SDS glove boxes are installed could be happened due to over currents. Therefore, it is common practice to consider only self ignited cable fires to occur in power cable trays since they carry enough electrical energy for ignition. In general, electrical cables typically do not carry enough electrical energy for self ignition. According to NUREG/CR 5384, it was concluded that electrical cables which passed the IEEE 383 74 flame test were less likely to propagate electrically initiated fires. However, the scenario in this fire accident analysis assumed that the IEEE 383 qualified cable is burned completely.

  9. Assessment of simulation predictions of hydrocarbon pool fire tests.

    Energy Technology Data Exchange (ETDEWEB)

    Luketa-Hanlin, Anay Josephine

    2010-04-01

    An uncertainty quantification (UQ) analysis is performed on the fuel regression rate model within SIERRA/Fuego by comparing to a series of hydrocarbon tests performed in the Thermal Test Complex. The fuels used for comparison for the fuel regression rate model include methanol, ethanol, JP8, and heptane. The recently implemented flamelet combustion model is also assessed with a limited comparison to data involving measurements of temperature and relative mole fractions within a 2-m diameter methanol pool fire. The comparison of the current fuel regression rate model to data without UQ indicates that the model over predicts the fuel regression rate by 65% for methanol, 63% for ethanol, 95% for JP8, and 15% for heptane. If a UQ analysis is performed incorporating a range of values for transmittance, reflectance, and heat flux at the surface the current model predicts fuel regression rates within 50% of measured values. An alternative model which uses specific heats at inlet and boiling temperatures respectively and does not approximate the sensible heat is also compared to data. The alternative model with UQ significantly improves the comparison to within 25% for all fuels except heptane. Even though the proposed alternative model provides better agreement to data, particularly for JP8 and ethanol (within 15%), there are still outstanding issues regarding significant uncertainties which include heat flux gauge measurement and placement, boiling at the fuel surface, large scale convective motion within the liquid, and semi-transparent behavior.

  10. A new heat transfer model for coupled processes in fire simulations; Ein neues Modell zur Simulation gekoppelter Waermetransportprozesse bei Braenden

    Energy Technology Data Exchange (ETDEWEB)

    Hohm, Volker [Ingenieurteam Trebes GmbH and Co. KG, Kiel (Germany); Hosser, Dietmar [Institut fuer Baustoffe, Massivbau und Brandschutz (iBMB), Technische Universitaet Braunschweig (Germany)

    2011-10-15

    The application of numerical fire simulations to validate and to evaluate the propagation of fire and smoke is already a fundamental part of the preparation of fire protection or safety concepts, especially in the field of performance-based designs. Against this background, the GFPA-guideline [10] has been developed in the recent years, which describes and classifies the available possibilities, approaches and models as well as provides suitable support for their application. Those programs and models respectively have to provide reliable results on the one hand and have to be efficient on the other hand. Hence, a heat transfer model for coupled processes in fire simulations was developed, which is able to represent the process of convective heat transfer between the gas phase and the solid phase for both horizontal and vertical, plane surfaces and in particular pipe and duct flows on the one hand and the process of heat conduction within multidimensional problems on the other hand physically correct. In addition to this the model is able to reproduce corresponding results using numerical simulation. The model was optimized both physically, by considering the specific fire effects and characteristics, and numerically, by selecting adequate numerical methods, for the integrated usage within numerical fire simulations. It has a modular design, so it is suitable for integration into current and future fire simulation codes. Additionally, a basis was established with and within this model for a later expansion with appropriate pyrolysis models. For that, an interface is provided with the embedded source term on the one hand and the required multidimensional temperature fields are determined precisely by the model on the other hand. A for the completion and demonstration concluding necessary integration of the developed model into a state-of-the-art fire simulation code was exemplarily and successfully performed. Finally, the model was successfully applied amongst

  11. Analysis and simulation on continuous fire frequency of coordinate air defense in warship formation%舰艇编队协同防空连续射击次数仿真分析

    Institute of Scientific and Technical Information of China (English)

    范英飚; 姚跃亭; 高波; 刘林密

    2011-01-01

    To calculate the fire frequency of coordinate air defense in fleet, a calculation model restrained by kill zone depth, course shortcut and interval length between ships is presented. Using the geometrical relationship between missile-target encounter point and the launch point, also with the inductive approach, models of single ship anti-air missile fire frequency to target with zero or none zero course shortcuts are brought forward. The total firing frequency of fleet air defense is divided into two parts: fires from ship under attack and covering fires from adjacent ship, and the covering kill zone depth of the latter part is inducted with constrains of maximum and mini mum ranges. Thus the covering fire frequency model is given. The fleet firing frequency sensitivities to key parameters such as velocity,course angle and interval length is studied with a simulation example, and results show that the calculation model is instructive.%为解决舰艇编队协同防空中的射击次数计算问题,提出了受杀伤区纵深,航路捷径和舰艇间隔距离约束的计算模型.利用导弹发射时刻至弹目遭遇时间内弹目之间的几何关系,经过归纳递推得到单艘舰艇零航路捷径和非零航路捷径时的舰空导弹射击次数模型.将编队协同防空的射击次数计算分解为被攻击舰和邻舰的射击次数之和,依据编队协同防空的几何关系得到邻舰掩护杀伤区纵深,得到了该纵深的远界和近界约束,进而得到邻舰的舰空导弹掩护射击次数模型.结合实例,研究了编队连续射击次数对目标速度、舷角和舰艇间隔距离等关键参数的敏感度,表明了模型的可行性和实用性.

  12. Analysis of the chemical composition of ultrafine particles from two domestic solid biomass fired room heaters under simulated real-world use

    Science.gov (United States)

    Ozgen, Senem; Becagli, Silvia; Bernardoni, Vera; Caserini, Stefano; Caruso, Donatella; Corbella, Lorenza; Dell'Acqua, Manuela; Fermo, Paola; Gonzalez, Raquel; Lonati, Giovanni; Signorini, Stefano; Tardivo, Ruggero; Tosi, Elisa; Valli, Gianluigi; Vecchi, Roberta; Marinovich, Marina

    2017-02-01

    Two common types of wood (beech and fir) were burned in commercial pellet (11.1 kW) and wood (8.2 kW) stoves following a combustion cycle simulating the behavior of a real-world user. Ultrafine particulate matter (UFP, dp carbon, and PAH content. The measurement of the number concentration and size distribution was also performed by a fourth multistage impactor. UFP mass emission factors averaged to 424 mg/kgfuel for all the tested stove and wood type (fir, beech) combinations except for beech log burning in the wood stove (838 mg/kgfuel). Compositional differences were observed for pellets and wood UFP samples, where high TC levels characterize the wood log combustion and potassium salts are dominant in every pellet sample. Crucial aspects determining the UFP composition in the wood stove experiments are critical situations in terms of available oxygen (a lack or an excess of combustion air) and high temperatures. Whereas for the automatically controlled pellets stove local situations (e.g., hindered air-fuel mixing due to heaps of pellets on the burner pot) determine the emission levels and composition. Wood samples contain more potentially carcinogenic PAHs with respect to pellets samples. Some diagnostic ratios related to PAH isomers and anhydrosugars compiled from experimental UFP data in the present study and compared to literature values proposed for the emission source discrimination for atmospheric aerosol, extend the evaluation usually limited to higher particle size fractions also to UFP.

  13. Fire hazard analysis for Plutonium Finishing Plant complex

    Energy Technology Data Exchange (ETDEWEB)

    MCKINNIS, D.L.

    1999-02-23

    A fire hazards analysis (FHA) was performed for the Plutonium Finishing Plant (PFP) Complex at the Department of Energy (DOE) Hanford site. The scope of the FHA focuses on the nuclear facilities/structures in the Complex. The analysis was conducted in accordance with RLID 5480.7, [DOE Directive RLID 5480.7, 1/17/94] and DOE Order 5480.7A, ''Fire Protection'' [DOE Order 5480.7A, 2/17/93] and addresses each of the sixteen principle elements outlined in paragraph 9.a(3) of the Order. The elements are addressed in terms of the fire protection objectives stated in paragraph 4 of DOE 5480.7A. In addition, the FHA also complies with WHC-CM-4-41, Fire Protection Program Manual, Section 3.4 [1994] and WHC-SD-GN-FHA-30001, Rev. 0 [WHC, 1994]. Objectives of the FHA are to determine: (1) the fire hazards that expose the PFP facilities, or that are inherent in the building operations, (2) the adequacy of the fire safety features currently located in the PFP Complex, and (3) the degree of compliance of the facility with specific fire safety provisions in DOE orders, related engineering codes, and standards.

  14. ASTM standards for fire debris analysis: a review.

    Science.gov (United States)

    Stauffer, Eric; Lentini, John J

    2003-03-12

    The American Society for Testing and Materials (ASTM) recently updated its standards E 1387 and E 1618 for the analysis of fire debris. The changes in the classification of ignitable liquids are presented in this review. Furthermore, a new standard on extraction of fire debris with solid phase microextraction (SPME) was released. Advantages and drawbacks of this technique are presented and discussed. Also, the standard on cleanup by acid stripping has not been reapproved. Fire debris analysts that use the standards should be aware of these changes.

  15. UTILIZATION OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY FIRE DYNAMICS SIMULATION COMPUTER MODEL

    Energy Technology Data Exchange (ETDEWEB)

    L. BARTLEIN

    2001-05-01

    The objective of this report is to provide a methodology for utilization of the NIST FDS code to evaluate the effects of radiant and convective heating from single and multiple fire sources, on heat sensitive targets as Special Nuclear Materials (SNM), and High Explosives (HE). The presentation will demonstrate practical applications of the FDS computer program in fire hazards analysis, and illustrate the advantages over hand calculations for radiant heat and convective transfer and fire progression. The ''visualization'' of radiant and convective heat effects will be demonstrated as a tool for supporting conclusions of fire hazards analysis and TSR development.

  16. Reflections on the Application of Fire Risk Simulation Technology%关于火灾模拟技术应用和发展的思考

    Institute of Scientific and Technical Information of China (English)

    王卫剑

    2011-01-01

    火灾模拟技术为性能化设计提供依据和分析手段,促进了消防技术的发展。对火灾模拟技术进行了综述,介绍了火灾模拟技术在防灭火工作中的应用,对我国火灾模拟技术发展进行了展望。%Fire risk simulation technology provides the means for performance-based fire prevention design and analysis and promotes the development of fire technology.This paper reviews fire risk simulation technology and introduces its application in fire prevention,and its future direction.

  17. Characteristic Analysis of Fire Modeling Codes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yoon Hwan; Yang, Joon Eon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Jong Hoon [Kyeongmin College, Ujeongbu (Korea, Republic of)

    2004-04-15

    This report documents and compares key features of four zone models: CFAST, COMPBRN IIIE, MAGIC and the Fire Induced Vulnerability Evaluation (FIVE) methodology. CFAST and MAGIC handle multi-compartment, multi-fire problems, using many equations; COMPBRN and FIVE handle single compartment, single fire source problems, using simpler equation. The increased rigor of the formulation of CFAST and MAGIC does not mean that these codes are more accurate in every domain; for instance, the FIVE methodology uses a single zone approximation with a plume/ceiling jet sublayer, while the other models use a two-zone treatment without a plume/ceiling jet sublayer. Comparisons with enclosure fire data indicate that inclusion of plume/ceiling jet sublayer temperatures is more conservative, and generally more accurate than neglecting them. Adding a plume/ceiling jet sublayer to the two-zone models should be relatively straightforward, but it has not been done yet for any of the two-zone models. Such an improvement is in progress for MAGIC.

  18. A comparative numerical study of turbulence models for the simulation of fire incidents: Application in ventilated tunnel fires

    Directory of Open Access Journals (Sweden)

    Konstantinos G. Stokos

    2015-12-01

    Full Text Available The objective of this paper is to compare the overall performance of two turbulence models used for the simulation of fire scenarios in ventilated tunnels. Two Reynolds Averaged Navier–Stokes turbulence models were used; the low-Re k–ω SST and the standard k–ε model with wall functions treatment. Comparison was conducted on two different fire scenarios. The varied parameters were the heat release rate and the ventilation rate. Results predicted by the two turbulence models were also compared to the results produced from the commercial package Ansys Fluent. Quite faster simulations were performed using the k–ε turbulence model with wall functions and our findings, as to the basic characteristics of smoke movement, were in good agreement with Ansys Fluent ones.

  19. Numerical simulation for recognition of coalfield fire areas by Rayleigh waves

    Institute of Scientific and Technical Information of China (English)

    Hu Mingshun; Pan Dongming; Chen Shenen; Dong Shouhua; Li Juanjuan

    2013-01-01

    Effective recognition of a coalfield fire area improves fire-fighting efficiency and helps avoid potential geological hazards.Coalfield fire areas are hard to detect accurately using general geophysical methods.This paper describes simulations of shallow,buried coalfield fires based on real geological conditions.Recognizing the coalfield fire by Rayleigh wave is proposed.Four representative geological models are constructed,namely; the non-burning model,the pseudo-burning model,the real-burning model,and the hidden-burning model.Numerical simulation using these models shows many markedly different characteristics between them in terms of Rayleigh wave dispersion and Eigen displacement.These characteristics,as well as the shear wave velocity obtained by inverting the fundamental dispersion,make it possible to distinguish the type of the coalfield fire area and indentify the real and serious coalfield fire area.The results are very helpful for future application of Rayleigh waves for the detection of coalfield fire area.

  20. Experimental study and advanced CFD simulation of fire safety performance of building external wall insulation system

    Directory of Open Access Journals (Sweden)

    Yan Zhenghua

    2013-11-01

    Full Text Available Large scale fire tests of building external wall insulation system were conducted. In the experiment, thermal-couples were mounted to measure the insulation system surface temperature and the gas temperature inside rooms at the second and third floors. Photos were also taken during the fire tests. The measurement provides information of the ignition and fire spread of the external insulation system which consists of surface protection layer, glass fibre net, bonding thin layer, anchor and the load bearing wall. Comprehensive simulations of the fire tests were carried out using an advanced CFD fire simulation software Simtec (Simulation of Thermal Engineering Complex [1, 2], which is now released by Simtec Soft Sweden, with the turbulent flow, turbulent combustion, thermal radiation, soot formation, convective heat transfer, the fully coupled three dimensional heat transfer inside solid materials, the ‘burn-out' of the surface protection layer and the pyrolysis of the insulation layer, etc, all computed. The simulation is compared with experimental measurement for validation. The simulation well captured the burning and fire spread of the external insulation wall.

  1. Modeling the Effect of Climate Change on Large Fire Size, Counts, and Intensities Using the Large Fire Simulator (FSim)

    Science.gov (United States)

    Riley, K. L.; Haas, J. R.; Finney, M.; Abatzoglou, J. T.

    2013-12-01

    Changes in climate can be expected to cause changes in wildfire activity due to a combination of shifts in weather (temperature, precipitation, relative humidity, wind speed and direction) and vegetation. Changes in vegetation could include type conversions, altered forest structure, and shifts in species composition, the effects of which could be mitigated or exacerbated by management activities. Further, changes in suppression response and effectiveness may alter potential wildfire activity, as well as the consequences of wildfire. Feedbacks among these factors are extremely complex and uncertain. The ability to anticipate changes driven by fire weather (largely outside of human control) can lead to development of fire and fuel management strategies aimed at mitigating current and future risk. Therefore, in this study we focus on isolating the effects of climate-induced changes in weather on wildfire activity. Specifically, we investigated the effect of changes in weather on fire activity in the Canadian Rockies ecoregion, which encompasses Glacier National Park and several large wilderness areas to the south. To model the ignition, growth, and containment of wildfires, we used the Large Fire Simulator (FSim), which we coupled with current and projected future climatic conditions. Weather streams were based on data from 14 downscaled Global Circulation Models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5) using the Representative Concentration Pathways (RCP) 45 and 85 for the years 2040-2060. While all GCMs indicate increases in temperature for this area, which would be expected to exacerbate fire activity, precipitation predictions for the summer wildfire season are more variable, ranging from a decrease of approximately 50 mm to an increase of approximately 50 mm. Windspeeds are generally predicted to decrease, which would reduce rates of spread and fire intensity. The net effect of these weather changes on the size, number, and intensity

  2. Simulating fire regimes in the Amazon in response to climate change and deforestation.

    Science.gov (United States)

    Silvestrini, Rafaella Almeida; Soares-Filho, Britaldo Silveira; Nepstad, Daniel; Coe, Michael; Rodrigues, Hermann; Assunção, Renato

    2011-07-01

    Fires in tropical forests release globally significant amounts of carbon to the atmosphere and may increase in importance as a result of climate change. Despite the striking impacts of fire on tropical ecosystems, the paucity of robust spatial models of forest fire still hampers our ability to simulate tropical forest fire regimes today and in the future. Here we present a probabilistic model of human-induced fire occurrence for the Amazon that integrates the effects of a series of anthropogenic factors with climatic conditions described by vapor pressure deficit. The model was calibrated using NOAA-12 night satellite hot pixels for 2003 and validated for the years 2002, 2004, and 2005. Assessment of the fire risk map yielded fitness values > 85% for all months from 2002 to 2005. Simulated fires exhibited high overlap with NOAA-12 hot pixels regarding both spatial and temporal distributions, showing a spatial fit of 50% within a radius of 11 km and a maximum yearly frequency deviation of 15%. We applied this model to simulate fire regimes in the Amazon until 2050 using IPCC's A2 scenario climate data from the Hadley Centre model and a business-as-usual (BAU) scenario of deforestation and road expansion from SimAmazonia. Results show that the combination of these scenarios may double forest fire occurrence outside protected areas (PAs) in years of extreme drought, expanding the risk of fire even to the northwestern Amazon by midcentury. In particular, forest fires may increase substantially across southern and southwestern Amazon, especially along the highways slated for paving and in agricultural zones. Committed emissions from Amazon forest fires and deforestation under a scenario of global warming and uncurbed deforestation may amount to 21 +/- 4 Pg of carbon by 2050. BAU deforestation may increase fires occurrence outside PAs by 19% over the next four decades, while climate change alone may account for a 12% increase. In turn, the combination of climate change

  3. Feasibility Analysis of a Type of Soft Firing Technology with Pneumatic Transmission

    Institute of Scientific and Technical Information of China (English)

    YANG Jun-rong; MI Liang-chuan; ZHAO Hua

    2006-01-01

    Aimed at solving the conflict between the requirements of reducing gun recoil and increasing muzzle velocity, a new type of soft firing technology with pneumatic transmission is put forward. By mathematical model and instance simulation, the feasibility analysis of this technique is made. The result shows that the soft firing technology with pneumatic transmission can reduce the maximum pressure on the breechblock by 27 % and increase the muzzle velocity by 20 %. The proposed new approach has the significance to the compatibility of power and flexibility.

  4. Coupled Atmosphere-Fire Simulations of Fireflux: Impacts of Model Resolution on Model Performance

    CERN Document Server

    Kochanski, Adam K; Jenkins, M A; Mandel, J; Beezley, J D

    2011-01-01

    The ability to forecast grass fire spread could be of a great importance for agencies making decisions about prescribed burns. However, the usefulness of the models used for fire-spread predictions is limited by the time required for completing the coupled atmosphere-fire simulations. In this study we analyze the sensitivity of a coupled model with respect to the vertical resolution of the atmospheric grid and the resolution of fire mesh that both affect computational performance of the model. Based on the observations of the plume properties recorded during the FireFlux experiment (Clements et al., 2007), we try to establish the optimal model configuration that provides realistic results for the least computational expense.

  5. Water Quality Analysis Simulation

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Water Quality analysis simulation Program, an enhancement of the original WASP. This model helps users interpret and predict water quality responses to natural...

  6. Development of PIRT and Assessment Matrix for Verification and Validation of Sodium Fire Analysis Codes

    Science.gov (United States)

    Ohno, Shuji; Ohshima, Hiroyuki; Tajima, Yuji; Ohki, Hiroshi

    Thermodynamic consequence in liquid sodium leak and fire accident is one of the important issues to be evaluated when considering the safety aspect of fast reactor plant building. The authors are therefore initiating systematic verification and validation (V&V) activity to assure and demonstrate the reliability of numerical simulation tool for sodium fire analysis. The V&V activity is in progress with the main focuses on already developed sodium fire analysis codes SPHINCS and AQUA-SF. The events to be evaluated are hypothetical sodium spray, pool, or combined fire accidents followed by thermodynamic behaviors postulated in a plant building. The present paper describes that the ‘Phenomena Identification and Ranking Table (PIRT)’ is developed at first for clarifying the important validation points in the sodium fire analysis codes, and that an ‘Assessment Matrix’ is proposed which summarizes both separate effect tests and integral effect tests for validating the computational models or whole code for important phenomena. Furthermore, the paper shows a practical validation with a separate effect test in which the spray droplet combustion model of SPHINCS and AQUA-SF predicts the burned amount of a falling sodium droplet with the error mostly less than 30%.

  7. A review of modern challenges in fire debris analysis.

    Science.gov (United States)

    Baerncopf, Jamie; Hutches, Katherine

    2014-11-01

    The continually-evolving field of fire debris analysis presents challenges to examiners on a regular basis. This article combines an overview of the scientific literature with novel samples that illustrate the current issues faced by fire debris examiners. Unusual liquids that contradict current classification schemes are discussed, as are complex matrices with noteworthy interferences. The matrix effects range from inherent interferences to the degradation of ignitable liquids. Finally, non-routine analyses are discussed, including the analysis of vegetable and lubricating oils and novel ignition methods. Through open discussion of complex samples and individual experiences, the problems in fire debris analysis can be overcome, resulting in the production of accurate and authoritative information.

  8. Sensitivity Analysis of a Simplified Fire Dynamic Model

    DEFF Research Database (Denmark)

    Sørensen, Lars Schiøtt; Nielsen, Anker

    2015-01-01

    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...... 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 (tp) 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...

  9. Global fire activity patterns (1996-2006) and climatic influence: an analysis using the World Fire Atlas

    Science.gov (United States)

    Le Page, Y.; Pereira, J. M. C.; Trigo, R.; da Camara, C.; Oom, D.; Mota, B.

    2008-04-01

    Vegetation fires have been acknowledged as an environmental process of global scale, which affects the chemical composition of the troposphere, and has profound ecological and climatic impacts. However, considerable uncertainty remains, especially concerning intra and inter-annual variability of fire incidence. The main goals of our global-scale study were to characterise spatial-temporal patterns of fire activity, to identify broad geographical areas with similar vegetation fire dynamics, and to analyse the relationship between fire activity and the El Niño-Southern Oscillation. This study relies on 10 years (mid 1996-mid 2006) of screened European Space Agency World Fire Atlas (WFA) data, obtained from Along Track Scanning Radiometer (ATSR) and Advanced ATSR (AATSR) imagery. Empirical Orthogonal Function analysis was used to reduce the dimensionality of the dataset. Regions of homogeneous fire dynamics were identified with cluster analysis, and interpreted based on their eco-climatic characteristics. The impact of 1997-1998 El Niño is clearly dominant over the study period, causing increased fire activity in a variety of regions and ecosystems, with variable timing. Overall, this study provides the first global decadal assessment of spatial-temporal fire variability and confirms the usefulness of the screened WFA for global fire ecoclimatology research.

  10. Forest Fires and Post - Fire Regeneration in Algeria Analysis with Satellite Data

    Science.gov (United States)

    Zegrar, Ahmed

    2016-07-01

    The Algerian forests are characterized by a particularly flammable material and fuel. The wind, the relief and the slope facilitates the propagation of fire. The use of remote sensing data multi-­dates, combined with other types of data of various kinds on the environment and forest burned, opens up interesting perspectives for the management of post-­fire regeneration. In this study the use of multi-­temporal remote sensing image Alsat-­1 and Landsat combined with other types of data concerning both background and burned down forest appears to be promising in evaluating and spatial and temporal effects of post fire regeneration. A spatial analysis taking into consideration the characteristics of the burned down site in the North West of Algeria, allowed to better account new factors to explain the regeneration and its temporal and spatial variation. We intended to show the potential use of remote sensing data from satellite ALSAT-­1, of spatial resolution of 32 m. . This approach allows showing the contribution of the data of Algerian satellite ALSAT in the detection and the well attended some forest fires in Algeria.

  11. DAYCENT Simulations to Test the Influence of Fire Regime and Fire Suppression on Trace Gas Fluxes and Nitrogen Biogeochemistry of Colorado Forests

    Directory of Open Access Journals (Sweden)

    Mark A. Gathany

    2012-07-01

    Full Text Available Biological activity and the physical environment regulate greenhouse gas fluxes (CH4, N2O and NO from upland soils. Wildfires are known to alter these factors such that we collected daily weather records, fire return intervals, or specific fire years, and soil data of four specific sites along the Colorado Front Range. These data were used as primary inputs into DAYCENT. In this paper we test the ability of DAYCENT to simulate four forested sites in this area and to address two objectives: (1 to evaluate the short-term influence of fire on trace gas fluxes from burned landscapes; and (2 to compare trace gas fluxes among locations and between pre-/post- fire suppression. The model simulations indicate that CH4 oxidation is relatively unaffected by wildfire. In contrast, gross nitrification rates were reduced by 13.5–37.1% during the fire suppression period. At two of the sites, we calculated increases in gross nitrification rates (>100%, and N2O and NO fluxes during the year of fire relative to the year before a fire. Simulated fire suppression exhibited decreased gross nitrification rates presumably as nitrogen is immobilized. This finding concurs with other studies that highlight the importance of forest fires to maintain soil nitrogen availability.

  12. 基于 ADAMS 机枪射击稳定性动力学仿真分析%Dynamic Simulation Analysis on Firing Stability of Machine Gun Based on ADAMS

    Institute of Scientific and Technical Information of China (English)

    黄晓; 金永灿; 赵东艳; 廖振强; 张茂文

    2016-01-01

    针对大口径机枪射击稳定性低的问题,提出一种利用膛内火药气体能量来减小枪口跳动的稳定控制装置;鉴于枪管在稳定力作用下会发生变形,采用一种支架装置来加强枪管的刚度;基于刚柔糅合、多柔体动力学理论,以ADAMS、Matlab 软件为平台,对改进后的机枪进行仿真,枪口跳动的最大位移值下降了46%,脚架振动的最大位移值下降了41%,射击稳定性得到明显提高。%Aiming at the problem of low firing stability of large caliber machine gun,a stability control de-vice using the energy of the propellant gas was proposed to reduce the jump of the muzzle.Considering the deformation of the barrel under the force of stability control device,a bracket device was applied to im-prove stiffness.The machine gun that has been changed was simulated to verify the firing stability of ma-chine gun by using ADAMS and Matlab software based on rigid-flexible coupling and mufti-degree flexible-body dynamics theory.The maximum displacement value of the muzzle is decreased by 46%.The maxi-mum displacement of tripod vibration is decreased by 41%,and the firing stability improves a lot.

  13. Experimental study and numerical simulation of spread law for fire on tunnel

    Institute of Scientific and Technical Information of China (English)

    牛会永; 乔晨露; 安敬鱼; 邓军

    2015-01-01

    In order to research spread law and distribution law of temperature nearby fire sources on roadway in mine, according to combustion theory and other basic, the theory model of temperature attenuation was determined under unsteady heat-exchange between wind and roadway wall. The full-size roadway fire simulation experiments were carried out in Chongqing Research Institute of China Coal Technology & Engineering Group Corporation. The development processes of mine fire and flow pattern of high temperature gas were analyzed. Experimental roadway is seen as physical model, and through using CFD software, the processes of mine fire have been simulated on computer. The results show that, after fire occurs, if the wind speed is less than the minimum speed which can prevent smoke from rolling back, then the smaller wind speed can cause smoke to roll back easily. Hot plume will lead to secondary disasters in upwind side. Because of roadway wall, hot plume released from roadway fire zone has caused the occurrence of the ceiling jet, and the hot plume has been forced down. Whereas, owing to the higher temperature, buoyancy effect is more obvious. Therefore, smoke rises gradually along the roadway in the flow process, and the hierarchical interface appears wavy. Oxygen-enriched combustion and fuel-enriched combustion are the two kinds of combustion states of fire. The oxygen content of downwind side of fire is maintained at around 15% for oxygen-enriched combustion, and the oxygen content of downwind side of fire is maintained at around 2% for fuel-enriched combustion. Furthermore, fuel-enriched combustion can lead to secondary disasters easily.

  14. Simulating the response of natural ecosystems and their fire regimes to climatic variability in Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Bachelet, D. [Oregon State Univ., Corvallis, OR (United States). Dept. of Bioengineering; Lenihan, J.; Neilson, R.; Drapek, R. [USDA Forest Service, Corvallis, OR (United States). Northwest Research Station; Kittel, T. [Colorado Univ., Boulder, CO (United States). Inst. of Arctic and Alpine Research

    2005-09-01

    The global dynamic vegetation model MC1 was used to examine fire, climate and ecosystems interactions in Alaska under future and historical climate conditions by simulating life-form mixtures and vegetation types, fluxes of carbon, nitrogen, water and fire. The model was run separately for each grid cell with no exchange of information across cells, reading climate data at a monthly time step with a special fire module interpolating the data to create daily inputs. Monthly mean minimum and maximum temperature, monthly precipitation and humidity and solar radiation time series were derived from various sources and station records to model historical conditions. Transient climate change scenarios were based on coupled atmosphere-ocean general circulation model experiments. Projections showed that by the end of the twenty-first century, 75-90 per cent of area simulated as tundra in 1922 was replaced by boreal and temperate forests. From 1922-1996, results showed carbon losses from fires, and an increase in fire emissions and burned areas under future climate change scenarios. Loss to fires was greater than the carbon gained. Despite increases in fire losses, the model simulated an increase in carbon gains from increased vegetation growth due to warmer temperatures during the twenty-first century. However, as regional drought stress can lead to increases in fires as well as insect disturbances, a temperature threshold may be reached that will reduce tree growth, as may have already happened in the white spruces in the boreal forests of interior Alaska. 63 refs., 3 tabs., 10 figs.

  15. The simulation of air recirculation and fire/explosion phenomena within a semiconductor factory.

    Science.gov (United States)

    I, Yet-Pole; Chiu, Yi-Long; Wu, Shi-Jen

    2009-04-30

    The semiconductor industry is the collection of capital-intensive firms that employ a variety of hazardous chemicals and engage in the design and fabrication of semiconductor devices. Owing to its processing characteristics, the fully confined structure of the fabrication area (fab) and the vertical airflow ventilation design restrict the applications of traditional consequence analysis techniques that are commonly used in other industries. The adverse situation also limits the advancement of a fire/explosion prevention design for the industry. In this research, a realistic model of a semiconductor factory with a fab, sub-fabrication area, supply air plenum, and return air plenum structures was constructed and the computational fluid dynamics algorithm was employed to simulate the possible fire/explosion range and its severity. The semiconductor factory has fan module units with high efficiency particulate air filters that can keep the airflow uniform within the cleanroom. This condition was modeled by 25 fans, three layers of porous ceiling, and one layer of porous floor. The obtained results predicted very well the real airflow pattern in the semiconductor factory. Different released gases, leak locations, and leak rates were applied to investigate their influence on the hazard range and severity. Common mitigation measures such as a water spray system and a pressure relief panel were also provided to study their potential effectiveness to relieve thermal radiation and overpressure hazards within a fab. The semiconductor industry can use this simulation procedure as a reference on how to implement a consequence analysis for a flammable gas release accident within an air recirculation cleanroom.

  16. Determination of Ignitable Liquids in Fire Debris: Direct Analysis by Electronic Nose

    Directory of Open Access Journals (Sweden)

    Marta Ferreiro-González

    2016-05-01

    Full Text Available Arsonists usually use an accelerant in order to start or accelerate a fire. The most widely used analytical method to determine the presence of such accelerants consists of a pre-concentration step of the ignitable liquid residues followed by chromatographic analysis. A rapid analytical method based on headspace-mass spectrometry electronic nose (E-Nose has been developed for the analysis of Ignitable Liquid Residues (ILRs. The working conditions for the E-Nose analytical procedure were optimized by studying different fire debris samples. The optimized experimental variables were related to headspace generation, specifically, incubation temperature and incubation time. The optimal conditions were 115 °C and 10 min for these two parameters. Chemometric tools such as hierarchical cluster analysis (HCA and linear discriminant analysis (LDA were applied to the MS data (45–200 m/z to establish the most suitable spectroscopic signals for the discrimination of several ignitable liquids. The optimized method was applied to a set of fire debris samples. In order to simulate post-burn samples several ignitable liquids (gasoline, diesel, citronella, kerosene, paraffin were used to ignite different substrates (wood, cotton, cork, paper and paperboard. A full discrimination was obtained on using discriminant analysis. This method reported here can be considered as a green technique for fire debris analyses.

  17. A study of the effects of a Micelle Encapsulator Fire Suppression Agent on dynamic headspace analysis of fire debris samples.

    Science.gov (United States)

    McGee, Eamonn; Lang, Terri L

    2002-03-01

    The effects of a Micelle Encapsulator Fire Suppression Agent (F-500, Hazard Control Technologies Inc., Fayetteville, Georgia) on the routine analysis of fire debris samples by Gas Chromatography (GC) were studied. When mixed with water the product can be used in the suppression of Class A and Class B fires. Laboratory tests were performed to determine whether or not the product has any effect on the analysis for ignitable liquids by GC, in particular for gasoline, medium petroleum distillates. and heavy petroleum distillates. Test burns were suppressed using either the micelle encapsulator or water and samples collected from these burns were analyzed. The results of analysis show that use of the micelle encapsulator at a fire scene may affect the chromatographic data obtained from samples collected by the investigator. However, the effect does not prevent the identification of common ignitable liquids in fire debris samples.

  18. Fire disturbance and vegetation dynamics : analysis and models

    Science.gov (United States)

    Thonicke, Kirsten

    2003-04-01

    Studies of the role of disturbance in vegetation or ecosystems showed that disturbances are an essential and intrinsic element of ecosystems that contribute substantially to ecosystem health, to structural diversity of ecosystems and to nutrient cycling at the local as well as global level. Fire as a grassland, bush or forest fire is a special disturbance agent, since it is caused by biotic as well abiotic environmental factors. Fire affects biogeochemical cycles and plays an important role in atmospheric chemistry by releasing climate-sensitive trace gases and aerosols, and thus in the global carbon cycle by releasing approximately 3.9 Gt C p.a. through biomass burning. A combined model to describe effects and feedbacks between fire and vegetation became relevant as changes in fire regimes due to land use and land management were observed and the global dimension of biomass burnt as an important carbon flux to the atmosphere, its influence on atmospheric chemistry and climate as well as vegetation dynamics were emphasized. The existing modelling approaches would not allow these investigations. As a consequence, an optimal set of variables that best describes fire occurrence, fire spread and its effects in ecosystems had to be defined, which can simulate observed fire regimes and help to analyse interactions between fire and vegetation dynamics as well as to allude to the reasons behind changing fire regimes. Especially, dynamic links between vegetation, climate and fire processes are required to analyse dynamic feedbacks and effects of changes of single environmental factors. This led us to the point, where new fire models had to be developed that would allow the investigations, mentioned above, and could help to improve our understanding of the role of fire in global ecology. In conclusion of the thesis, one can state that moisture conditions, its persistence over time and fuel load are the important components that describe global fire pattern. If time series of

  19. A Drone Remote Sensing for Virtual Reality Simulation System for Forest Fires: Semantic Neural Network Approach

    Science.gov (United States)

    Narasimha Rao, Gudikandhula; Jagadeeswara Rao, Peddada; Duvvuru, Rajesh

    2016-09-01

    Wild fires have significant impact on atmosphere and lives. The demand of predicting exact fire area in forest may help fire management team by using drone as a robot. These are flexible, inexpensive and elevated-motion remote sensing systems that use drones as platforms are important for substantial data gaps and supplementing the capabilities of manned aircraft and satellite remote sensing systems. In addition, powerful computational tools are essential for predicting certain burned area in the duration of a forest fire. The reason of this study is to built up a smart system based on semantic neural networking for the forecast of burned areas. The usage of virtual reality simulator is used to support the instruction process of fire fighters and all users for saving of surrounded wild lives by using a naive method Semantic Neural Network System (SNNS). Semantics are valuable initially to have a enhanced representation of the burned area prediction and better alteration of simulation situation to the users. In meticulous, consequences obtained with geometric semantic neural networking is extensively superior to other methods. This learning suggests that deeper investigation of neural networking in the field of forest fires prediction could be productive.

  20. Advanced char burnout models for the simulation of pulverized coal fired boilers

    Energy Technology Data Exchange (ETDEWEB)

    T. Severin; S. Wirtz; V. Scherer [Ruhr-University, Bochum (Germany). Institute of Energy Plant Technology (LEAT)

    2005-07-01

    The numerical simulation of coal combustion processes is widely used as an efficient means to predict burner or system behaviour. In this paper an approach to improve CFD simulations of pulverized coal fired boilers with advanced coal combustion models is presented. In simple coal combustion models, first order Arrhenius rate equations are used for devolatilization and char burnout. The accuracy of such simple models is sufficient for the basic aspects of heat release. The prediction of carbon-in-ash is one aspect of special interest in the simulation of pulverized coal fired boilers. To determine the carbon-in-ash levels in the fly ash of coal fired furnaces, the char burnout model has to be more detailed. It was tested, in how far changing operating conditions affect the carbon-in-ash prediction of the simulation. To run several test cases in a short time, a simplified cellnet model was applied. To use a cellnet model for simulations of pulverized coal fired boilers, it was coupled with a Lagrangian particle model, used in CFD simulations, too. 18 refs., 5 figs., 5 tabs.

  1. Numerical Simulation of Multistory Building Fire with Zone—Modeling Method

    Institute of Scientific and Technical Information of China (English)

    FuZhuman; FanWeicheng

    1996-01-01

    Based on the basic idea of zone modeling method,a two-layer zone model is developed and programmed to calculate the fire growth and smoke spread in a multi-room buiding subjected to a fire.The related predictive equations,numerical simulation method and sub-models implemented in this model are concisely described.A set of experimental data from Cooper's work at NIST for a two-room compartment fire are chosen for comparison with the model and program,and the numerical results fundamentally agree well with the experimental data,Then,an example of numerical calculation of a two-stoy duilding fire is presented,and the relevant output results are given and analyzed.

  2. Numerical simulations of LNG vapor dispersion in Brayton Fire Training Field tests with ANSYS CFX.

    Science.gov (United States)

    Qi, Ruifeng; Ng, Dedy; Cormier, Benjamin R; Mannan, M Sam

    2010-11-15

    Federal safety regulations require the use of validated consequence models to determine the vapor cloud dispersion exclusion zones for accidental liquefied natural gas (LNG) releases. One tool that is being developed in industry for exclusion zone determination and LNG vapor dispersion modeling is computational fluid dynamics (CFD). This paper uses the ANSYS CFX CFD code to model LNG vapor dispersion in the atmosphere. Discussed are important parameters that are essential inputs to the ANSYS CFX simulations, including the atmospheric conditions, LNG evaporation rate and pool area, turbulence in the source term, ground surface temperature and roughness height, and effects of obstacles. A sensitivity analysis was conducted to illustrate uncertainties in the simulation results arising from the mesh size and source term turbulence intensity. In addition, a set of medium-scale LNG spill tests were performed at the Brayton Fire Training Field to collect data for validating the ANSYS CFX prediction results. A comparison of test data with simulation results demonstrated that CFX was able to describe the dense gas behavior of LNG vapor cloud, and its prediction results of downwind gas concentrations close to ground level were in approximate agreement with the test data.

  3. Toward an integrated system for fire, smoke, and air quality simulations

    CERN Document Server

    Kochanski, Adam K; Yedinak, Kara; Mandel, Jan; Beezley, Jonathan D; Lamb, Brian

    2014-01-01

    In this study, we describe how WRF-Sfire is coupled with WRF-Chem to construct WRFSC, an integrated forecast system for wildfire and smoke prediction. The integrated forecast system has the advantage of not requiring a simple plume-rise model and assumptions about the size and heat release from the fire in order to determine fire emissions into the atmosphere. With WRF-Sfire, wildfire spread, plume and plume-top heights are predicted directly, at every WRF timestep, providing comprehensive meteorology and fire emissions to the chemical transport model WRF-Chem. Evaluation of WRFSC was based on comparisons between available observations to the results of two WRFSC simulations. The study found overall good agreement between forecasted and observed fire spread and smoke transport for the Witch-Guejito fire. Also the simulated PM2.5 (fine particulate matter) peak concentrations matched the observations. However, the NO and ozone levels were underestimated in the simulations and the peak concentrations were mistim...

  4. Analysis of pressure safety valves for fire protection on offshore oil and gas installations

    DEFF Research Database (Denmark)

    Bjerre, Michael Skov; Eriksen, Jacob; Andreasen, Anders

    2017-01-01

    The effectiveness of fire Pressure Safety Valves (PSV) has been investigated when offshore process equipment is exposed to a fire. Simulations of several typical offshore pressure vessels have been performed using the commercial software VessFire. The pressure vessels are exposed to a small jet f...

  5. Production and efficiency of large wildland fire suppression effort: A stochastic frontier analysis.

    Science.gov (United States)

    Katuwal, Hari; Calkin, David E; Hand, Michael S

    2016-01-15

    This study examines the production and efficiency of wildland fire suppression effort. We estimate the effectiveness of suppression resource inputs to produce controlled fire lines that contain large wildland fires using stochastic frontier analysis. Determinants of inefficiency are identified and the effects of these determinants on the daily production of controlled fire line are examined. Results indicate that the use of bulldozers and fire engines increase the production of controlled fire line, while firefighter crews do not tend to contribute to controlled fire line production. Production of controlled fire line is more efficient if it occurs along natural or built breaks, such as rivers and roads, and within areas previously burned by wildfires. However, results also indicate that productivity and efficiency of the controlled fire line are sensitive to weather, landscape and fire characteristics.

  6. Hazard analysis system of urban post-earth-quake fire based on GIS

    Institute of Scientific and Technical Information of China (English)

    李杰; 江建华; 李明浩

    2001-01-01

    The authors study the structure, functions and data organization for the hazard analysis system of urban post-earthquake fire on the platform of GIS. A general hazard analysis model of the post-earthquake fire is presented. Taking Shanghai central district as background, a system for hazard analysis of the post-earthquake fire and auxili-ary decision-against fire is developed.

  7. Surface dimming by the 2013 Rim Fire simulated by a sectional aerosol model

    Science.gov (United States)

    Yu, Pengfei; Toon, Owen B.; Bardeen, Charles G.; Bucholtz, Anthony; Rosenlof, Karen H.; Saide, Pablo E.; Da Silva, Arlindo; Ziemba, Luke D.; Thornhill, Kenneth L.; Jimenez, Jose-Luis; Campuzano-Jost, Pedro; Schwarz, Joshua P.; Perring, Anne E.; Froyd, Karl D.; Wagner, N. L.; Mills, Michael J.; Reid, Jeffrey S.

    2016-06-01

    The Rim Fire of 2013, the third largest area burned by fire recorded in California history, is simulated by a climate model coupled with a size-resolved aerosol model. Modeled aerosol mass, number, and particle size distribution are within variability of data obtained from multiple-airborne in situ measurements. Simulations suggest that Rim Fire smoke may block 4-6% of sunlight energy reaching the surface, with a dimming efficiency around 120-150 W m-2 per unit aerosol optical depth in the midvisible at 13:00-15:00 local time. Underestimation of simulated smoke single scattering albedo at midvisible by 0.04 suggests that the model overestimates either the particle size or the absorption due to black carbon. This study shows that exceptional events like the 2013 Rim Fire can be simulated by a climate model with 1° resolution with overall good skill, although that resolution is still not sufficient to resolve the smoke peak near the source region.

  8. Suppression of pool fires with HRC-125 in a simulated engine nacelle.

    Energy Technology Data Exchange (ETDEWEB)

    Keyser, David R. (INS, Inc., Lexington Park, MD); Hewson, John C.

    2007-06-01

    CFD simulations are conducted to predict the distribution of fire suppressant in an engine nacelle and to predict the suppression of pool fires by the application of this suppressant. In the baseline configuration, which is based on an installed system, suppressant is injected through four nozzles at a rate fast enough to suppress all simulated pool fires. Variations that reduce the mass of the suppression system (reducing the impact of the suppression system on meeting mission needs) are considered, including a reduction in the rate of suppressant injection, a reduction in the mass of suppressant and a reduction in the number of nozzles. In general, these variations should work to reduce the effectiveness of the suppression system, but the CFD results point out certain changes that have negligible impact, at least for the range of phenomena considered here. The results are compared with measurements where available. Comparisons with suppressant measurements are reasonable. A series of twenty-three fire suppression tests were conducted to check the predictions. The pre-test predictions were generally successful in identifying the range of successful suppression tests. In two separate cases, each where one nozzle of the suppression system was capped, the simulation results did indicate a failure to suppress for a condition where the tests indicated successful suppression. When the test-suppressant discharge rate was reduced by roughly 25%, the tests were in agreement with the predictions. That is, the simulations predict a failure to suppress slightly before observed in these cases.

  9. High temperature corrosion under conditions simulating biomass firing: depth-resolved phase identification

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Montgomery, Melanie; Jappe Frandsen, Flemming;

    2014-01-01

    Both cross-sectional and plan view, ‘top-down’ characterization methods were employed , for a depth-resolved characterization of corrosion products resulting from high temperature corrosion under laboratory conditions simulating biomass firing. Samples of an austenitic stainless steel (TP 347H FG...

  10. Non-PR Majors Catch Fire in "Northville" Simulation.

    Science.gov (United States)

    Deats, Tom

    1981-01-01

    Classroom simulation can prove effective in improving the overall quality of a public relations course for nonjournalism majors by helping to blend theory with practice and by creating student interest. (HOD)

  11. Dynamic Characteristics Analysis and Simulation Evaluation of a Portable Fire Water Monitor with Valve-controlled Cylinder System%采用阀控缸进行自动换向控制的移动式消防水炮动态特性研究

    Institute of Scientific and Technical Information of China (English)

    胡国良; 龙铭; 高志刚

    2012-01-01

    Fire water monitor is one of the main equipment widely used in the fire fighting.A portable fire water monitor with valve-controlled cylinder system was designed.The back and forth movement of the monitor head is controlled by the valve-controlled cylinder system,which is driven by the inlet water pressure.The hydraulic performance of the portable fire water monitor was numerically simulated by using Fluent software.The simulation results show that the outlet velocity is feasible,which is favorable in the jet range.At the same time,the modeling and simulation analysis were carried out for the valve-controlled cylinder system by using AMESim software,the simulation results indicate that this system can self-swing in a particular frequency,and the self-swinging frequency is increasing with the increases of inlet water pressure.Finally,the experiment tests at field verify that the designed fire water monitor can meet the requirements of the jet range,and the self-swinging frequency of the monitor head can also satisfy the design requirement.This type of portable fire water monitor can be used in the situations that are beyond the reach of the firemen or the fire engines.%消防水炮是消防作战中主要灭火装备之一.设计了一种移动式消防水炮,采用阀控缸水力自动换向控制装置,利用自身水压力驱动水液压缸带动水炮炮头摆动,并采用机械反馈装置使炮头自动换向.采用Fluent流场仿真软件对水炮流道结构进行仿真分析.结果表明,所设计消防水炮水力学性能较好,结构设计比较合理.利用AMESim液压机械仿真软件对该水力自摆控制系统进行建模仿真分析.仿真结果表明,该水力自摆系统能够在水压力驱动下以一定的频率进行自动换向,并且在水压力升高的情况下,其摆动频率也会上升.实验验证该水炮能满足灭火覆盖范围和射程的要求,炮头自动换向频率也能满足设计要求.所设计的带阀控缸自摆装

  12. Fire Research Enclosure

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Simulates submarine fires, enclosed aircraft fires, and fires in enclosures at shore facilities .DESCRIPTION: FIRE I is a pressurizable, 324 cu m(11,400 cu...

  13. Fire Research Enclosure

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Simulates submarine fires, enclosed aircraft fires, and fires in enclosures at shore facilities . DESCRIPTION: FIRE I is a pressurizable, 324 cu m(11,400...

  14. FASA – Fire Airborne Spectral Analysis of natural disasters

    Directory of Open Access Journals (Sweden)

    F. Schrandt

    2006-06-01

    Full Text Available At present the authors are developing the system FASA, an airborne combination of a Fourier Transform Spectrometer and an imaging system. The aim is to provide a system that is usable to investigate and monitor emissions from natural disasters such as wild fires and from volcanoes. Besides temperatures and (burned areas FASA will also provide concentration profiles of the gaseous combustion products. These data are needed to improve the knowledge of the effects of such emissions on the global ecosystem. The paper presents a description of the instrumentation, the data evaluation procedure and shows first results of retrieval calculations based on simulated spectra.

  15. Mapping forest fire risk zones with spatial data and principal component analysis

    Institute of Scientific and Technical Information of China (English)

    XU; Dong; Guofan; Shao; DAI; Limin; HAO; Zhanqing; TANG; Lei; WANG; Hui

    2006-01-01

    By integrating forest inventory data with remotely sensed data, new data layers for factors that affect forest fire potentials were generated for Baihe Forestry Bureau in Jilin Province of China. The principle component analysis was used to sort out the relationships between forest fire potentials and environmental factors. The classifications of these factors were performed with GIS, generating three maps: a fuel-based fire risk map, a topography-based fire risk map, and an anthropogenic-factor fire risk map. These three maps were then synthesized to generate the final fire risk map. The linear regression method was used to analyze the relationship between an area-weighted value of forest fire risks and the frequency of historical forest fires at each forest farm. The results showed that the most important factor contributing to forest fire ignition was topography, followed by anthropogenic factors.

  16. SIMULATION OF FIRE DYNAMICS WITH VARIOUS GROWTH RATE IN PREMISES WITH NATURAL VENTILATION

    Directory of Open Access Journals (Sweden)

    V. V. Nevdakh

    2015-01-01

    Full Text Available Computer simulation of the initial fire stage dynamics with various growth rate have been carried out with the help of FDS software. In case of a quick fire 1055 kW heat liberation has been reached in accordance with quadratic law within 100 seconds, averagely within 250 seconds and within 500 seconds when the fire rate is slow. Source of fire has been located on the floor and at the height of 2 m. A doorway of 0.8×2.0 m size and two 0.8×0.1 m openings have been used as ventilation holes. One opening has been located at the bottom over the floor and the other one has been positioned under the ceiling. It has been established that in the process of their development fires change their character in the following way: at the initial stage they are controlled by inflammable materials and then the fires are controlled by oxygen. At the first stage heat liberation is changed in accordance with the same law which is used for mass rate of an inflammable material and flame combustion is observed only in the field of the fire source. At the second stage heat liberation dynamics has a form of pulsations which are irregular in amplitude and duration and the dynamics becomes dependable on ventilation conditions. At this stage flame combustion in the source zone and/or self-ignition in the smoke layer provide a corresponding contribution in fire heat liberation.It has been determined that two layers have been formed in case of a fire in the premises with ventilation in the spatial distribution of temperature and air fumigation. These top and bottom layers are practically uniform and they are characterized by irregular pulsations of the parameters which are due to smoke self-ignition occurrence. The paper shows relationship of these distributions with spatial distribution of air pressure changes in the premises during a fire. A significant dependence of heat liberation dynamics on fire source location height is observed at all fire growth rates. An increase

  17. Policy Options Analysis and the National Fire Operations Reporting System

    Science.gov (United States)

    2015-06-01

    fire marshal or another office located within the state bureaucracy . The fire data is then forwarded to the United States Fire Administration at a...process. Organizational • Provides leadership to the fire service in the consensus development process. Budgetary • Does not have any contribution to

  18. Research on solar aided coal-fired power generation system and performance analysis

    Institute of Scientific and Technical Information of China (English)

    YANG YongPing; CUI YingHong; HOU HongJuan; GUO XiYan; YANG ZhiPing; WANG NinLing

    2008-01-01

    Integrationg rating solar power utilization systems with coal-fired power units, the solar aided coal-fired power generation (SACPG) shows a significant prospect for the large-scale utilization of solar energy and energy saving of thermal power units. The methods and mechanism of system integration were studied. The parabolic trough solar collectors were used to collect solar energy and the integration scheme of SACPG system was determined considering the matching of working fluid flows and energy flows. The thermodynamic characteristics of solar thermal power generation and their effects on the performance of thermal power units were studied, and based on this the integration and optimization model of system structure and parameters were built up. The integration rules and coupling mecha-nism of SACPG systems were summarized in accordance with simulation results. The economic analysis of this SACPG system showed that the solar LEC of a of SEGS, 0.14 S/kW. h.

  19. Computational Analysis of Mixing and Transport of Air and Fuel in Co-Fired Combustor

    Directory of Open Access Journals (Sweden)

    Javaid Iqbal

    2015-01-01

    Full Text Available Computational analysis for air fuel mixing and transport in a combustor used for co fired burner has been done by RANS (Reynolds-Averaged Navier?Stokes model comparing with 3D (Three Dimensional LES (Large Eddy Simulation. To investigate the better turbulence level and mixing within co fired combustor using the solid fuel biomass with coal is main purpose of this research work. The results show the difference in flow predicted by the two models, LES give better results than the RANS. For compressible flow the LES results show more swirling effect, The velocity decays along axial and radial distance for both swirling and non-swirling jet. Because of no slip condition near boundary the near the wall velocity is about zero

  20. Computational Fluid Dynamics Modeling of a wood-burning stove-heated sauna using NIST's Fire Dynamics Simulator

    CERN Document Server

    Macqueron, Corentin

    2014-01-01

    The traditional sauna is studied from a thermal and fluid dynamics standpoint using the NIST's Fire Dynamics Simulator (FDS) software. Calculations are performed in order to determine temperature and velocity fields, heat flux, soot and steam cloud transport, etc. Results are discussed in order to assess the reliability of this new kind of utilization of the FDS fire safety engineering software.

  1. Numerical simulations of the ISO 13785-2 façade fire tests

    Directory of Open Access Journals (Sweden)

    Hostikka Simo

    2016-01-01

    Full Text Available In this work we created a numerical model of the ISO 13785-2 test setup for testing the fire behaviour of building façade systems, and used the model to simulate the thermal environment on the façade. The model, created using Fire Dynamics Simulator –software, was first validated using the experimental data by Yoshioka et al.(2012. Next, the sensitivity of the façade heat fluxes on the geometrical and model parameters was studied, revealing for instance that the size of the combustion chamber window will influence the thermal exposure high above the window. Finally, the model was used to estimate the thickness of non-combustible insulation layer that is needed to protect combustible materials from melting or decomposition.

  2. Spatio-Temporal Analysis of Forest Fire Risk and Danger Using LANDSAT Imagery

    Directory of Open Access Journals (Sweden)

    Ömer Kücük

    2008-06-01

    Full Text Available Computing fire danger and fire risk on a spatio-temporal scale is of crucial importance in fire management planning, and in the simulation of fire growth and development across a landscape. However, due to the complex nature of forests, fire risk and danger potential maps are considered one of the most difficult thematic layers to build up. Remote sensing and digital terrain data have been introduced for efficient discrete classification of fire risk and fire danger potential. In this study, two time-series data of Landsat imagery were used for determining spatio-temporal change of fire risk and danger potential in Korudag forest planning unit in northwestern Turkey. The method comprised the following two steps: (1 creation of indices of the factors influencing fire risk and danger; (2 evaluation of spatio-temporal changes in fire risk and danger of given areas using remote sensing as a quick and inexpensive means and determining the pace of forest cover change. Fire risk and danger potential indices were based on species composition, stand crown closure, stand development stage, insolation, slope and, proximity of agricultural lands to forest and distance from settlement areas. Using the indices generated, fire risk and danger maps were produced for the years 1987 and 2000. Spatio-temporal analyses were then realized based on the maps produced. Results obtained from the study showed that the use of Landsat imagery provided a valuable characterization and mapping of vegetation structure and type with overall classification accuracy higher than 83%.

  3. Spatio-Temporal Analysis of Forest Fire Risk and Danger Using LANDSAT Imagery

    Science.gov (United States)

    Sağlam, Bülent; Bilgili, Ertuğrul; Durmaz, Bahar Dinç; Kadıoğulları, Ali İhsan; Küçük, Ömer

    2008-01-01

    Computing fire danger and fire risk on a spatio-temporal scale is of crucial importance in fire management planning, and in the simulation of fire growth and development across a landscape. However, due to the complex nature of forests, fire risk and danger potential maps are considered one of the most difficult thematic layers to build up. Remote sensing and digital terrain data have been introduced for efficient discrete classification of fire risk and fire danger potential. In this study, two time-series data of Landsat imagery were used for determining spatio-temporal change of fire risk and danger potential in Korudag forest planning unit in northwestern Turkey. The method comprised the following two steps: (1) creation of indices of the factors influencing fire risk and danger; (2) evaluation of spatio-temporal changes in fire risk and danger of given areas using remote sensing as a quick and inexpensive means and determining the pace of forest cover change. Fire risk and danger potential indices were based on species composition, stand crown closure, stand development stage, insolation, slope and, proximity of agricultural lands to forest and distance from settlement areas. Using the indices generated, fire risk and danger maps were produced for the years 1987 and 2000. Spatio-temporal analyses were then realized based on the maps produced. Results obtained from the study showed that the use of Landsat imagery provided a valuable characterization and mapping of vegetation structure and type with overall classification accuracy higher than 83%. PMID:27879918

  4. Validation/Uncertainty Quantification for Large Eddy Simulations of the heat flux in the Tangentially Fired Oxy-Coal Alstom Boiler Simulation Facility

    Energy Technology Data Exchange (ETDEWEB)

    Smith, P.J.; Eddings, E.G.; Ring, T.; Thornock, J.; Draper, T.; Isaac, B.; Rezeai, D.; Toth, P.; Wu, Y.; Kelly, K.

    2014-08-01

    The objective of this task is to produce predictive capability with quantified uncertainty bounds for the heat flux in commercial-scale, tangentially fired, oxy-coal boilers. Validation data came from the Alstom Boiler Simulation Facility (BSF) for tangentially fired, oxy-coal operation. This task brings together experimental data collected under Alstom’s DOE project for measuring oxy-firing performance parameters in the BSF with this University of Utah project for large eddy simulation (LES) and validation/uncertainty quantification (V/UQ). The Utah work includes V/UQ with measurements in the single-burner facility where advanced strategies for O2 injection can be more easily controlled and data more easily obtained. Highlights of the work include: • Simulations of Alstom’s 15 megawatt (MW) BSF, exploring the uncertainty in thermal boundary conditions. A V/UQ analysis showed consistency between experimental results and simulation results, identifying uncertainty bounds on the quantities of interest for this system (Subtask 9.1) • A simulation study of the University of Utah’s oxy-fuel combustor (OFC) focused on heat flux (Subtask 9.2). A V/UQ analysis was used to show consistency between experimental and simulation results. • Measurement of heat flux and temperature with new optical diagnostic techniques and comparison with conventional measurements (Subtask 9.3). Various optical diagnostics systems were created to provide experimental data to the simulation team. The final configuration utilized a mid-wave infrared (MWIR) camera to measure heat flux and temperature, which was synchronized with a high-speed, visible camera to utilize two-color pyrometry to measure temperature and soot concentration. • Collection of heat flux and temperature measurements in the University of Utah’s OFC for use is subtasks 9.2 and 9.3 (Subtask 9.4). Several replicates were carried to better assess the experimental error. Experiments were specifically designed for the

  5. Formal Probabilistic Analysis of a Wireless Sensor Network for Forest Fire Detection

    Directory of Open Access Journals (Sweden)

    Sofiène Tahar

    2013-07-01

    Full Text Available Wireless Sensor Networks (WSNs have been widely explored for forest fire detection, which is considered a fatal threat throughout the world. Energy conservation of sensor nodes is one of the biggest challenges in this context and random scheduling is frequently applied to overcome that. The performance analysis of these random scheduling approaches is traditionally done by paper-and-pencil proof methods or simulation. These traditional techniques cannot ascertain 100% accuracy, and thus are not suitable for analyzing a safety-critical application like forest fire detection using WSNs. In this paper, we propose to overcome this limitation by applying formal probabilistic analysis using theorem proving to verify scheduling performance of a real-world WSN for forest fire detection using a k-set randomized algorithm as an energy saving mechanism. In particular, we formally verify the expected values of coverage intensity, the upper bound on the total number of disjoint subsets, for a given coverage intensity, and the lower bound on the total number of nodes.

  6. Laboratory Investigations of the High Temperature Corrosion of Various Materials in Simulated oxy-fuel and Conventional Coal Firing

    Energy Technology Data Exchange (ETDEWEB)

    Folkeson, N.; Pettersson, J.; Svensson, J.E. [Chalmers Univ. of Technology (Sweden); Hjornhede, A. [Vattenfall Power Consultant AB (Sweden); Montgomery, M. [Vattenfall Heat Nordic/DTU Mekanik (Denmark); Bjurman, M. [Vattenfall Research and Development AB (Sweden)

    2009-07-01

    Laboratory exposures in horizontal tube furnaces were conducted to test various materials for corrosion resistance in simulated oxy-fuel firing and conventional coal firing environments. Two different exposures were done at 630 C for 672 hours. The reaction atmosphere, consisting of CO{sub 2}, H{sub 2}O, O{sub 2}, N{sub 2} and SO{sub 2}, was mixed to resemble that of oxy-fuel firing in the first exposure and that of conventional coal firing in the second exposure (N{sub 2} was added during the second exposure only). Four different materials were tested in the first exposure; Sanicro 63, Alloy 800HT, 304L and 304HCu. In the second exposure four different materials were tested; 304L, Alloy 800HT, Kanthal APMT and NiCrAl. Apart from cleaned sample coupons, some samples pre-exposed in a test rig under oxy-fuel conditions with lignite as fuel and some pre-exposed with bituminous coal as fuel were investigated in the first exposure. In the second exposure some samples were pre-exposed in a rig under conventional firing conditions with lignite as fuel. The corrosion attack on the investigated samples was analysed by gravimetry, x-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive x-ray (EDX). The SEM/EDX analysis was made on both the sample envelope and metallographic cross sections of the samples. The results show that there is small difference in the corrosion attack between the two environments. There was also little difference in oxide morphology and composition between cleaned samples and pre-exposed samples of the same material. The austenitic chromia former 304HCu suffered the most extensive corrosion attack in the oxy-fuel environment. In the conventional air firing environment 304L showed the highest mass gain. Chromia formers with higher chromium concentrations performed better, especially the super austenitic Alloy 800HT, with its high chromium concentration, formed a thin and protective corundum type oxide. The nickel based

  7. Simulation of the Evolution of Floor Covering Ceramic Tiles During the Firing

    Science.gov (United States)

    Peris-Fajarnés, Guillermo; Defez, Beatriz; Serrano, Ricardo; Ruiz, Oscar E.

    2013-04-01

    Finding the geometry and properties of a ceramic tile after its firing using simulations, is relevant because several defects can occur and the tile can be rejected if the conditions of the firing are inadequate for the geometry and materials of the tile. Previous works present limitations because they do not use a model characteristic of ceramics at high temperatures and they oversimplify the simulations. As a response to such shortcomings, this article presents a simulation with a three-dimensional Norton's model, which is characteristic of ceramics at high temperatures. The results of our simulated experiments show advantages with respect to the identification of the mechanisms that contribute to the final shape of the body. Our work is able to divide the history of temperatures in stages where the evolution of the thermal, elastic, and creep deformations is simplified and meaningful. That is achieved because our work found that curvature is the most descriptive parameter of the simulation. Future work is to be realized in the creation of a model that takes into account that the shrinkage is dependent on the history of temperatures.

  8. EVENT-DRIVEN SIMULATION OF INTEGRATE-AND-FIRE MODELS WITH SPIKE-FREQUENCY ADAPTATION

    Institute of Scientific and Technical Information of China (English)

    Lin Xianghong; Zhang Tianwen

    2009-01-01

    The evoked spike discharges of a neuron depend critically on the recent history of its electrical activity. A well-known example is the phenomenon of spike-frequency adaptation that is a commonly observed property of neurons. In this paper, using a leaky integrate-and-fire model that includes an adaptation current, we propose an event-driven strategy to simulate integrate-and-fire models with spike-frequency adaptation. Such approach is more precise than traditional clock-driven numerical integration approach because the timing of spikes is treated exactly. In experiments, using event-driven and clock-driven strategies we simulated the adaptation time course of single neuron and the random network with spike-timing dependent plasticity, the results indicate that (1) the temporal precision of spiking events impacts on neuronal dynamics of single as well as network in the different simulation strategies and (2) the simulation time scales linearly with the total number of spiking events in the event-driven simulation strategies.

  9. Analysis of underground fires in Polish hard coal mines

    Institute of Scientific and Technical Information of China (English)

    WACHOWICZ Jan

    2008-01-01

    In the period of the first twenty years after World War II the number of fires in Polish hard coal mines reached annually the value of several thousands of cases. About 80% of fires constituted spontaneous fires. Investigations into the development of new methods of fire hazard prediction and implementation of new methods and means of fire prevention as well as the introduction of prohibition concerning the use of products manufactured of combustible organic materials in underground mine workings re-duced considerably the hazard of underground fire rise. The worked out at the Central Mining Institute (GIG) new method of un-derground fire prediction allows the correct selection of fire prevention means. The introduction into common use of fire-resistant conveyor belts, the main factor giving rise to spontaneous fires, and methods of assessment of their fire resistance eliminated prac-tically the fire hazard. These activities contributed in an efficient way to the reduction of the number of underground fires to a sa-tisfactory level.

  10. Safety analysis of the existing 850 Firing Facility

    Energy Technology Data Exchange (ETDEWEB)

    Odell, B.N.

    1986-06-05

    A safety analysis was performed to determine if normal operations and/or potential accidents at the 850 Firing Facility at Site 300 could present undue hazards to the general public, personnel at Site 300, or have an adverse effect on the environment. The normal operations and credible accidents that might have an effect on these facilities or have off-site consequences were considered. It was determined by this analysis that all but one of the hazards were either low or of the type or magnitude routinely encountered and/or accepted by the public. The exception was explosives, which was classified as a moderate hazard per the requirements given in DOE Order 5481.1A. This safety analysis concluded that the operation at this facility will present no undue risk to the health and safety of LLNL employees or the public.

  11. Safety analysis of the existing 851 Firing Facility

    Energy Technology Data Exchange (ETDEWEB)

    Odell, B.N.

    1986-06-05

    A safety analysis was performed to determine if normal operations and/or potential accidents at the 851 Firing Facility at Site 300 could present undue hazards to the general public, personnel at Site 300, or have an adverse effect on the environment. The normal operations and credible accidents that might have an effect on these facilities or have off-site consequences were considered. It was determined by this analysis that all but two of the hazards were either low or of the type or magnitude routinely encountered and/or accepted by the public. The exceptions were the linear accelerator and explosives, which were classified as moderate hazards per the requirements given in DOE Order 5481.1A. This safety analysis concluded that the operation at this facility will present no undue risk to the health and safety of LLNL employees or the public.

  12. Uncertainty and Sensitivity Analysis of a Fire-Induced Accident Scenario Involving Binary Variables and Mechanistic Codes

    Science.gov (United States)

    2010-09-10

    Simulation of Fire Scenarios, VTT Building and Transport, PO Box 1803, FIN-02044 VTT , Finland, 2003. [11] Fire PRA Methods Enhancements: Additions...FMSNL 21 INPUT TO PFS I. CFAST CONTROL PFS: Probabilistic Fire Simulator v4.0 CFAST Model and Execution Control VTT Technical Research Centre

  13. Time and length scales within a fire and implications for numerical simulation

    Energy Technology Data Exchange (ETDEWEB)

    TIESZEN,SHELDON R.

    2000-02-02

    A partial non-dimensionalization of the Navier-Stokes equations is used to obtain order of magnitude estimates of the rate-controlling transport processes in the reacting portion of a fire plume as a function of length scale. Over continuum length scales, buoyant times scales vary as the square root of the length scale; advection time scales vary as the length scale, and diffusion time scales vary as the square of the length scale. Due to the variation with length scale, each process is dominant over a given range. The relationship of buoyancy and baroclinc vorticity generation is highlighted. For numerical simulation, first principles solution for fire problems is not possible with foreseeable computational hardware in the near future. Filtered transport equations with subgrid modeling will be required as two to three decades of length scale are captured by solution of discretized conservation equations. By whatever filtering process one employs, one must have humble expectations for the accuracy obtainable by numerical simulation for practical fire problems that contain important multi-physics/multi-length-scale coupling with up to 10 orders of magnitude in length scale.

  14. Particle and gas emissions from a simulated coal-burning household fire pit

    Energy Technology Data Exchange (ETDEWEB)

    Linwei Tian; Donald Lucas; Susan L. Fischer; S. C. Lee; S. Katharine Hammond; Catherine P. Koshland [University of California, Berkeley, CA (United States). School of Public Health

    2008-04-01

    An open fire was assembled with firebricks to simulate the household fire pit used in rural China, and 15 different coals from this area were burned to measure the gaseous and particulate emissions. Particle size distribution was studied with a microorifice uniform-deposit impactor (MOUDI). Over 90% of the particulate mass was attributed to sub-micrometer particles. The carbon balance method was used to calculate the emission factors. Emission factors for four pollutants (particulate matter, CO{sub 2}, total hydrocarbons, and NOx) were 2-4 times higher for bituminous coals than for anthracites. In past inventories of carbonaceous emissions used for climate modeling, these two types of coal were not treated separately. The dramatic emission factor difference between the two types of coal warrants attention in the future development of emission inventories. 25 refs., 8 figs., 1 tab.

  15. Understanding coupled natural and human systems on fire prone landscapes: integrating wildfire simulation into an agent based planning system.

    Science.gov (United States)

    Barros, Ana; Ager, Alan; Preisler, Haiganoush; Day, Michelle; Spies, Tom; Bolte, John

    2015-04-01

    Agent-based models (ABM) allow users to examine the long-term effects of agent decisions in complex systems where multiple agents and processes interact. This framework has potential application to study the dynamics of coupled natural and human systems where multiple stimuli determine trajectories over both space and time. We used Envision, a landscape based ABM, to analyze long-term wildfire dynamics in a heterogeneous, multi-owner landscape in Oregon, USA. Landscape dynamics are affected by land management policies, actors decisions, and autonomous processes such as vegetation succession, wildfire, or at a broader scale, climate change. Key questions include: 1) How are landscape dynamics influenced by policies and institutions, and 2) How do land management policies and actor decisions interact to produce intended and unintended consequences with respect to wildfire on fire-prone landscapes. Applying Envision to address these questions required the development of a wildfire module that could accurately simulate wildfires on the heterogeneous landscapes within the study area in terms of replicating historical fire size distribution, spatial distribution and fire intensity. In this paper we describe the development and testing of a mechanistic fire simulation system within Envision and application of the model on a 3.2 million fire prone landscape in central Oregon USA. The core fire spread equations use the Minimum Travel Time algorithm developed by M Finney. The model operates on a daily time step and uses a fire prediction system based on the relationship between energy release component and historical fires. Specifically, daily wildfire probabilities and sizes are generated from statistical analyses of historical fires in relation to daily ERC values. The MTT was coupled with the vegetation dynamics module in Envision to allow communication between the respective subsystem and effectively model fire effects and vegetation dynamics after a wildfire. Canopy and

  16. The impacts of climate, land use, and demography on fires during the 21st century simulated by CLM-CN

    Science.gov (United States)

    Kloster, S.; Mahowald, N. M.; Randerson, J. T.; Lawrence, P. J.

    2012-01-01

    Landscape fires during the 21st century are expected to change in response to multiple agents of global change. Important controlling factors include climate controls on the length and intensity of the fire season, fuel availability, and fire management, which are already anthropogenically perturbed today and are predicted to change further in the future. An improved understanding of future fires will contribute to an improved ability to project future anthropogenic climate change, as changes in fire activity will in turn impact climate. In the present study we used a coupled-carbon-fire model to investigate how changes in climate, demography, and land use may alter fire emissions. We used climate projections following the SRES A1B scenario from two different climate models (ECHAM5/MPI-OM and CCSM) and changes in population. Land use and harvest rates were prescribed according to the RCP 45 scenario. In response to the combined effect of all these drivers, our model estimated, depending on our choice of climate projection, an increase in future (2075-2099) fire carbon emissions by 17 and 62% compared to present day (1985-2009). The largest increase in fire emissions was predicted for Southern Hemisphere South America for both climate projections. For Northern Hemisphere Africa, a region that contributed significantly to the global total fire carbon emissions, the response varied between a decrease and an increase depending on the climate projection. We disentangled the contribution of the single forcing factors to the overall response by conducting an additional set of simulations in which each factor was individually held constant at pre-industrial levels. The two different projections of future climate change evaluated in this study led to increases in global fire carbon emissions by 22% (CCSM) and 66% (ECHAM5/MPI-OM). The RCP 45 projection of harvest and land use led to a decrease in fire carbon emissions by -5%. The RCP 26 and RCP 60 harvest and landuse

  17. The impacts of climate, land use, and demography on fires during the 21st century simulated by CLM-CN

    Directory of Open Access Journals (Sweden)

    S. Kloster

    2011-09-01

    Full Text Available Landscape fires during the 21st century are expected to change in response to multiple agents of global change. Important controlling factors include climate controls on the length and intensity of the fire season, fuel availability, and fire management, which are already anthropogenically perturbed today and are predicted to change further in the future. An improved understanding of future fires will contribute to an improved ability to project future anthropogenic climate change, as changes in fire behavior will in turn impact climate.

    In the present study we used a coupled-carbon-fire model to investigate how changes in climate, demography, and land use may alter fire emissions. We used climate projections following the SRES A1B scenario from two different climate models (ECHAM5/MPI-OM and CCSM and changes in population. Land use and harvest rates were prescribed according to the RCP 45 scenario. In response to the combined effect of all these drivers, our model estimated, depending on our choice of climate projection, an increase in future (2075–2099 fire carbon emissions by 17 and 62% compared to present day (1985–2009. The largest increase in fire emissions was predicted for Southern Hemisphere South America for both climate projection. For Northern Hemisphere Africa, a region that contributed significantly to the global total fire carbon emissions, the response varied between a decrease and an increase depending on the climate projection.

    We disentangled the contribution of the single forcing factors to the overall response by conducting an additional set of simulations in which each factor was individually held constant at pre-industrial levels. The two different projections of future climate change evaluated in this study led to increases in global fire carbon emissions by 22% (CCSM and 66% (ECHAM5/MPI-OM. The RCP 45 projection of harvest and land use led to a decrease in fire carbon emissions by −5%. Changes in

  18. Computer simulation study of the relationship between the profile of excitatory postsynaptic potential and stimulus-correlated motoneuron firing.

    Science.gov (United States)

    Piotrkiewicz, Maria; Kudina, Lydia; Jakubiec, Michal

    2009-03-01

    This paper shows the results of computer simulation of changes in motoneuron (MN) firing evoked by a repetitively applied synaptic volley that consists of a single excitatory postsynaptic potential (EPSP). Spike trains produced by the threshold-crossing MN model were analyzed as experimental results. Various output functions were applied for analysis; the most useful was a peristimulus time histogram, a special modification of a raster plot and a peristimulus time frequencygram (PSTF). It has been shown that all functions complement each other in distinguishing between the genuine results evoked by the excitatory volley and the secondary results of the EPSP-evoked synchronization. The EPSP rising edge was best reproduced by the PSTF. However, whereas the EPSP rise time could be estimated quite accurately, especially for high EPSP amplitudes at high MN firing rates, the EPSP amplitude estimate was also influenced by factors unrelated to the synaptic volley, such as the afterhyperpolarization duration of the MN or the amplitude of synaptic noise, which cannot be directly assessed in human experiments. Thus, the attempts to scale any estimate of the EPSP amplitude in millivolts appear to be useless. The decaying phase of the EPSP cannot be reproduced accurately by any of the functions. For the short EPSPs, it is extinguished by the generation of an action potential and a subsequent decrease in the MN excitability. For longer EPSPs, it is inseparable from the secondary effects of synchronization. Thus, the methods aimed at extracting information about long-lasting and complex postsynaptic potentials from stimulus-correlated MN firing, should be refined, and the theoretical considerations checked in computer simulations.

  19. An Information Diffusion Technique for Fire Risk Analysis

    Institute of Scientific and Technical Information of China (English)

    刘静; 黄崇福

    2004-01-01

    There are many kinds of fires occurring under different conditions. For a specific site, it is difficult to collect sufficient data for analyzing the fire risk. In this paper, we suggest an information diffusion technique to analyze fire risk with a small sample. The information distribution method is applied to change crisp observations into fuzzy sets, and then to effectively construct a fuzzy relationship between fire and surroundings. With the data of Shanghai in winter, we show how to use the technique to analyze the fire risk.

  20. Analysis of Architectural Building Design Influences on Fire Spread in Densely Urban Settlement using Cellular Automata

    Science.gov (United States)

    Tambunan, L.; Salamah, H.; Asriana, N.

    2017-03-01

    This study aims to determine the influence of architectural design on the risk of fire spread in densely urban settlement area. Cellular Automata (CA) is used to analyse the fire spread pattern, speed, and the extent of damage. Four cells represent buildings, streets, and fields characteristic in the simulated area, as well as their flammability level and fire spread capabilities. Two fire scenarios are used to model the spread of fire: (1) fire origin in a building with concrete and wood material majority, and (2) fire origin in building with wood material majority. Building shape, building distance, road width, and total area of wall openings are considered constant, while wind is ignored. The result shows that fire spread faster in the building area with wood majority than with concrete majority. Significant amount of combustible building material, absence of distance between buildings, narrow streets and limited fields are factors which influence fire spread speed and pattern as well as extent of damage when fire occurs in the densely urban settlement area.

  1. Simulating boreal forest carbon dynamics after stand-replacing fire disturbance: insights from a global process-based vegetation model

    Directory of Open Access Journals (Sweden)

    C. Yue

    2013-04-01

    Full Text Available Stand-replacing fires are the dominant fire type in North American boreal forest and leave a historical legacy of a mosaic landscape of different aged forest cohorts. To accurately quantify the role of fire in historical and current regional forest carbon balance using models, one needs to explicitly simulate the new forest cohort that is established after fire. The present study adapted the global process-based vegetation model ORCHIDEE to simulate boreal forest fire CO2 emissions and follow-up recovery after a stand-replacing fire, with representation of postfire new cohort establishment, forest stand structure and the following self-thinning process. Simulation results are evaluated against three clusters of postfire forest chronosequence observations in Canada and Alaska. Evaluation variables for simulated postfire carbon dynamics include: fire carbon emissions, CO2 fluxes (gross primary production, total ecosystem respiration and net ecosystem exchange, leaf area index (LAI, and biometric measurements (aboveground biomass carbon, forest floor carbon, woody debris carbon, stand individual density, stand basal area, and mean diameter at breast height. The model simulation results, when forced by local climate and the atmospheric CO2 history on each chronosequence site, generally match the observed CO2 fluxes and carbon stock data well, with model-measurement mean square root of deviation comparable with measurement accuracy (for CO2 flux ~100 g C m−2 yr−1, for biomass carbon ~1000 g C m−2 and for soil carbon ~2000 g C m−2. We find that current postfire forest carbon sink on evaluation sites observed by chronosequence methods is mainly driven by historical atmospheric CO2 increase when forests recover from fire disturbance. Historical climate generally exerts a negative effect, probably due to increasing water stress caused by significant temperature increase without sufficient increase in precipitation. Our simulation results

  2. Study on Probabilistic Fire Safety Analysis Procedures%概率火灾安全分析方法研究

    Institute of Scientific and Technical Information of China (English)

    宋贤生; 陈驰; 刘英学

    2012-01-01

    为分析和评估火灾对设备、建筑物等敏感目标结构安全的影响,结合化工定量风险评估方法和气体爆炸概率安全分析方法,提出概率火灾安全分析策略和实施流程.该方法包括火灾危害辨识、泄漏速率计算、火灾后果模拟、频率分析、绘制频率超越热载荷曲线、结构响应分析等关键步骤.以某柴油罐区为例,通过频率分析和火灾模拟,绘制出频率超越热载荷曲线,假定火灾风险可接受准则为10 -4/a,求得对应的可信热载荷为21 kW/m2,并以此值作为结构热响应分析的输入参数.火灾概率安全分析方法侧重于描述火灾热辐射强度及其对应的发生可能性,判定敏感目标遭遇的可信火灾热载荷强度和结构热响应行为,评估消防减灾措施效果,确保结构完整性和可用性,不评价工艺系统潜在火灾风险的高低.%In order to analyze and evaluate fire impact on structural safety of equipment, building and other sensitive objects, strategies and implementation procedures of probabilistic fire safety analysis were proposed with reference to chemical process quantitative risk analysis approach and probabilistic gas explosion study approach. Such procedures included fire hazard identification of key components, leak calculation , consequence simulation, frequency analysis, frequency of exceedance heat load curve establishment and structure response analysis. Probabilistic fire safety study of a diesel tank farm was exemplified, in which frequency analysis and fire scenario simulation with FDS software were completed and frequency of exceedance heat load curve was plotted. If the assumed Risk Acceptance Criteria was lO'Vyr, the corresponding fire thermal flux level should be 21 kW/m2, which could be as input value for further structural thermal response analysis. Probabilistic fire safety analysis emphasizes describing fire thermal load and associated likelihood of occurrence, rather than

  3. Fire safety analysis of the Crystal palace based on optimized BIM model

    OpenAIRE

    Semič, Dejan

    2016-01-01

    This master's thesis comprehensively explores fire safety in high-rise buildings. A fire safety analysis was performed on a model of the Crystal Palace skyscraper, which, at 89 meters, is the tallest building in Slovenia today (2016). A BIM model of the entire building was generated (Archicad) to be used with the software for fire (PyroSim) and evacuation analysis (Pathfinder). The BIM model of the building was optimized in a way it could be directly imported into the software for fire and...

  4. Study on the Fire Damage Characteristics of the New Qidaoliang Highway Tunnel: Field Investigation with Computational Fluid Dynamics (CFD) Back Analysis

    Science.gov (United States)

    Lai, Hongpeng; Wang, Shuyong; Xie, Yongli

    2016-01-01

    In the New Qidaoliang Tunnel (China), a rear-end collision of two tanker trunks caused a fire. To understand the damage characteristics of the tunnel lining structure, in situ investigation was performed. The results show that the fire in the tunnel induced spallation of tunnel lining concrete covering 856 m3; the length of road surface damage reached 650 m; the sectional area had a maximum 4% increase, and the mechanical and electrical facilities were severely damaged. The maximum area loss happened at the fire spot with maximum observed concrete spallation up to a thickness of 35.4 cm. The strength of vault and side wall concrete near the fire source was significantly reduced. The loss of concrete strength of the side wall near the inner surface of tunnel was larger than that near the surrounding rock. In order to perform back analysis of the effect of thermal load on lining structure, simplified numerical simulation using computational fluid dynamics (CFD) was also performed, repeating the fire scenario. The simulated results showed that from the fire breaking out to the point of becoming steady, the tunnel experienced processes of small-scale warming, swirl around fire, backflow, and longitudinal turbulent flow. The influence range of the tunnel internal temperature on the longitudinal downstream was far greater than on the upstream, while the high temperature upstream and downstream of the transverse fire source mainly centered on the vault or the higher vault waist. The temperature of each part of the tunnel near the fire source had no obvious stratification phenomenon. The temperature of the vault lining upstream and downstream near the fire source was the highest. The numerical simulation is found to be in good agreement with the field observations. PMID:27754455

  5. Study on the Fire Damage Characteristics of the New Qidaoliang Highway Tunnel: Field Investigation with Computational Fluid Dynamics (CFD Back Analysis

    Directory of Open Access Journals (Sweden)

    Hongpeng Lai

    2016-10-01

    Full Text Available In the New Qidaoliang Tunnel (China, a rear-end collision of two tanker trunks caused a fire. To understand the damage characteristics of the tunnel lining structure, in situ investigation was performed. The results show that the fire in the tunnel induced spallation of tunnel lining concrete covering 856 m3; the length of road surface damage reached 650 m; the sectional area had a maximum 4% increase, and the mechanical and electrical facilities were severely damaged. The maximum area loss happened at the fire spot with maximum observed concrete spallation up to a thickness of 35.4 cm. The strength of vault and side wall concrete near the fire source was significantly reduced. The loss of concrete strength of the side wall near the inner surface of tunnel was larger than that near the surrounding rock. In order to perform back analysis of the effect of thermal load on lining structure, simplified numerical simulation using computational fluid dynamics (CFD was also performed, repeating the fire scenario. The simulated results showed that from the fire breaking out to the point of becoming steady, the tunnel experienced processes of small-scale warming, swirl around fire, backflow, and longitudinal turbulent flow. The influence range of the tunnel internal temperature on the longitudinal downstream was far greater than on the upstream, while the high temperature upstream and downstream of the transverse fire source mainly centered on the vault or the higher vault waist. The temperature of each part of the tunnel near the fire source had no obvious stratification phenomenon. The temperature of the vault lining upstream and downstream near the fire source was the highest. The numerical simulation is found to be in good agreement with the field observations.

  6. Study on the Fire Damage Characteristics of the New Qidaoliang Highway Tunnel: Field Investigation with Computational Fluid Dynamics (CFD) Back Analysis.

    Science.gov (United States)

    Lai, Hongpeng; Wang, Shuyong; Xie, Yongli

    2016-10-15

    In the New Qidaoliang Tunnel (China), a rear-end collision of two tanker trunks caused a fire. To understand the damage characteristics of the tunnel lining structure, in situ investigation was performed. The results show that the fire in the tunnel induced spallation of tunnel lining concrete covering 856 m³; the length of road surface damage reached 650 m; the sectional area had a maximum 4% increase, and the mechanical and electrical facilities were severely damaged. The maximum area loss happened at the fire spot with maximum observed concrete spallation up to a thickness of 35.4 cm. The strength of vault and side wall concrete near the fire source was significantly reduced. The loss of concrete strength of the side wall near the inner surface of tunnel was larger than that near the surrounding rock. In order to perform back analysis of the effect of thermal load on lining structure, simplified numerical simulation using computational fluid dynamics (CFD) was also performed, repeating the fire scenario. The simulated results showed that from the fire breaking out to the point of becoming steady, the tunnel experienced processes of small-scale warming, swirl around fire, backflow, and longitudinal turbulent flow. The influence range of the tunnel internal temperature on the longitudinal downstream was far greater than on the upstream, while the high temperature upstream and downstream of the transverse fire source mainly centered on the vault or the higher vault waist. The temperature of each part of the tunnel near the fire source had no obvious stratification phenomenon. The temperature of the vault lining upstream and downstream near the fire source was the highest. The numerical simulation is found to be in good agreement with the field observations.

  7. FIRE DESIGN: DIRECT COMPARISON BETWEEN FIRE CURVES. THE CASE STUDY OF A NURSERY

    Directory of Open Access Journals (Sweden)

    Mara Lombardi

    2013-01-01

    Full Text Available According to fire safety engineering, the present study analyzes fire design settings for simulation of fire in a nursery and proposes to compare simulations developed with a natural fire curve and nominal fire curve. Comparative analysis was developed according to thermo-fluid dynamic parameters that are relevant to the safety of the exposed and for the representative period of the danger flow to the exposed, which are mainly children between 0 and 3 years of age, helpless under ordinary conditions and even more so in case of emergency. Defined conditions of structure and ventilation, Two fire simulations, differentiated by fire curve, have been implemented: First simulation: the parameters have been derived from the simulation of a fire, characterized by analytic function of Heat Release Rate (HRR Second simulation: the HRR function was obtained ex post by making a simulation of natural fire in realistically furnished room by imposing a minimum effective primer. The simulated HRR curve, appropriately linearized, allows to estimate a Likely Fire Curve (LFC. The simulations have been developed for a time of about 15 min, starting from the ignition of fire whereas the flow of the danger is serious for exposed mainly in this first phase of fire. The comparison between the parameters of fire involved the Temperature-Time Curve and HRR-Time Curve of both simulations and the ISO 834 Curve, which is a consolidated benchmark in Fire Safety Engineering (FSE. The nominal curves have been introduced for the purpose of checking whether the structural strength and integrity: the adoption of these curves in the fire safety engineering was made by analogy, on the assumption that the phenomena of major intensity, that these curves represent, ensure a safe approach on the choice of the fire design. The study showed indeed that the analytical curve, adopted in order to verify the structural strength, produces fields of both temperature and toxic concentrations

  8. Using rainfall simulation to monitor the effect of fire on overland flow and erosion through time

    Science.gov (United States)

    Ferreira, Carla; Shakesby, Rick; Walsh, Rory; Ferreira, António; Urbanek, Emilia

    2010-05-01

    have been recorded if the plot had remained bounded between measurements These results show that this fire continued to have a significant impact on soil loss for a relatively long period. As regards the methodology adopted, the ability to keep the plots in fixed positions minimised soil disturbance due to plot installation and meant that results carried out at the same sites were directly comparable. Removing the upper and lower boundaries of the plots between measurements ensured that soil in the plots underwent processes similar to those experienced on the surrounding slope and avoided the ‘oasis' effect associated with bounded plots. It can be concluded that rainfall simulation experiments provide a good method for monitoring and assessing spatial and temporal differences in overland flow and erosion rates through time.

  9. Boreal forest fires in 1997 and 1998: a seasonal comparison using transport model simulations and measurement data

    Directory of Open Access Journals (Sweden)

    N. Spichtinger

    2004-01-01

    Full Text Available Forest fire emissions have a strong impact on the concentrations of trace gases and aerosols in the atmosphere. In order to quantify the influence of boreal forest fire emissions on the atmospheric composition, the fire seasons of 1997 and 1998 are compared in this paper. Fire activity in 1998 was very strong, especially over Canada and Eastern Siberia, whereas it was much weaker in 1997. According to burned area estimates the burning in 1998 was more than six times as intense as in 1997. Based on hot spot locations derived from ATSR (Along Track Scanning Radiometer data and official burned area data, fire emissions were estimated and their transport was simulated with a Lagrangian tracer transport model. Siberian and Canadian forest fire tracers were distinguished to investigate the transport of both separately. The fire emissions were transported even over intercontinental distances. Due to the El Niño induced meteorological situation, transport from Siberia to Canada was enhanced in 1998. Siberian fire emissions were transported towards Canada and contributed concentrations more than twice as high as those due to Canada's own CO emissions by fires. In 1998 both tracers arrive at higher latitudes over Europe, which is due to a higher North Atlantic Oscillation (NAO index in 1998. The simulated emission plumes are compared to CMDL (Climate Monitoring and Diagnostics Laboratory CO2 and CO data, Total Ozone Mapping Spectrometer (TOMS aerosol index (AI data and Global Ozone Monitoring Experiment (GOME tropospheric NO2 and HCHO columns. All the data show clearly enhanced signals during the burning season of 1998 compared to 1997. The results of the model simulation are in good agreement with ground-based as well as satellite-based measurements.

  10. Analysis of accelerants and fire debris using aroma detection technology

    Energy Technology Data Exchange (ETDEWEB)

    Barshick, S.A.

    1997-01-17

    The purpose of this work was to investigate the utility of electronic aroma detection technologies for the detection and identification of accelerant residues in suspected arson debris. Through the analysis of known accelerant residues, a trained neural network was developed for classifying suspected arson samples. Three unknown fire debris samples were classified using this neural network. The item corresponding to diesel fuel was correctly identified every time. For the other two items, wide variations in sample concentration and excessive water content, producing high sample humidities, were shown to influence the sensor response. Sorbent sampling prior to aroma detection was demonstrated to reduce these problems and to allow proper neural network classification of the remaining items corresponding to kerosene and gasoline.

  11. One-dimensional simulation of fire injection heights in contrasted meteorological scenarios with PRM and Meso-NH models

    Directory of Open Access Journals (Sweden)

    S. Strada

    2013-02-01

    Full Text Available Wild-fires release huge amounts of aerosol and hazardous trace gases in the atmosphere. The residence time and the dispersion of fire pollutants in the atmosphere can range from hours to days and from local to continental scales. These various scenarios highly depend on the injection height of smoke plumes. The altitude at which fire products are injected in the atmosphere is controlled by fire characteristics and meteorological conditions. Injection height however is still poorly accounted in chemistry transport models for which fires are sub-grid scale processes which need to be parametrised. Only recently, physically-based approaches for estimating the fire injection heights have been developed which consider both the convective updrafts induced by the release of fire sensible heat and the impact of background meteorological environment on the fire convection dynamics. In this work, two different models are used to simulate fire injection heights in contrasted meteorological scenarios: a Mediterranean arson fire and two Amazonian deforestation fires. A Eddy-Diffusivity/Mass-Flux approach, formerly developed to reproduce convective boundary layer in the non-hydrostatic meteorological model Meso-NH, is compared to the 1-D Plume Rise Model. For both models, radiosonde data and re-analyses from the European Center for Medium-Range Weather Forecasts (ECMWF have been used as initial conditions to explore the sensitivity of the models responses to different meteorological forcings. The two models predict injection heights for the Mediterranean fire between 1.7 and 3.3 km with the Meso-NH/EDMF model systematically higher than the 1-D PRM model. Both models show a limited sensitivity to the meteorological forcings with a 20–30% difference in the injection height between radiosondes and ECMWF data for this case. Injection heights calculated for the two Amazonian fires ranges from 5 to 6.5 km for the 1-D PRM model and from 2 to 4 km for the Meso

  12. One-dimensional simulation of fire injection heights in contrasted meteorological scenarios with PRM and Meso-NH models

    Science.gov (United States)

    Strada, S.; Freitas, S. R.; Mari, C.; Longo, K. M.; Paugam, R.

    2013-02-01

    Wild-fires release huge amounts of aerosol and hazardous trace gases in the atmosphere. The residence time and the dispersion of fire pollutants in the atmosphere can range from hours to days and from local to continental scales. These various scenarios highly depend on the injection height of smoke plumes. The altitude at which fire products are injected in the atmosphere is controlled by fire characteristics and meteorological conditions. Injection height however is still poorly accounted in chemistry transport models for which fires are sub-grid scale processes which need to be parametrised. Only recently, physically-based approaches for estimating the fire injection heights have been developed which consider both the convective updrafts induced by the release of fire sensible heat and the impact of background meteorological environment on the fire convection dynamics. In this work, two different models are used to simulate fire injection heights in contrasted meteorological scenarios: a Mediterranean arson fire and two Amazonian deforestation fires. A Eddy-Diffusivity/Mass-Flux approach, formerly developed to reproduce convective boundary layer in the non-hydrostatic meteorological model Meso-NH, is compared to the 1-D Plume Rise Model. For both models, radiosonde data and re-analyses from the European Center for Medium-Range Weather Forecasts (ECMWF) have been used as initial conditions to explore the sensitivity of the models responses to different meteorological forcings. The two models predict injection heights for the Mediterranean fire between 1.7 and 3.3 km with the Meso-NH/EDMF model systematically higher than the 1-D PRM model. Both models show a limited sensitivity to the meteorological forcings with a 20-30% difference in the injection height between radiosondes and ECMWF data for this case. Injection heights calculated for the two Amazonian fires ranges from 5 to 6.5 km for the 1-D PRM model and from 2 to 4 km for the Meso-NH/EDMF model. The

  13. Performance Analysis of a Coal-Fired External Combustion Compressed Air Energy Storage System

    Directory of Open Access Journals (Sweden)

    Wenyi Liu

    2014-11-01

    Full Text Available Compressed air energy storage (CAES is one of the large-scale energy storage technologies utilized to provide effective power peak load shaving. In this paper, a coal-fired external combustion CAES, which only uses coal as fuel, is proposed. Unlike the traditional CAES, the combustion chamber is substituted with an external combustion heater in which high-pressure air is heated before entering turbines to expand in the proposed system. A thermodynamic analysis of the proposed CAES is conducted on the basis of the process simulation. The overall efficiency and the efficiency of electricity storage are 48.37% and 81.50%, respectively. Furthermore, the exergy analysis is then derived and forecasted, and the exergy efficiency of the proposed system is 47.22%. The results show that the proposed CAES has more performance advantages than Huntorf CAES (the first CAES plant in the world. Techno-economic analysis of the coal-fired CAES shows that the cost of electricity (COE is $106.33/MWh, which is relatively high in the rapidly developing power market. However, CAES will be more likely to be competitive if the power grid is improved and suitable geographical conditions for storage caverns are satisfied. This research provides a new approach for developing CAES in China.

  14. Stochastic modeling analysis and simulation

    CERN Document Server

    Nelson, Barry L

    1995-01-01

    A coherent introduction to the techniques for modeling dynamic stochastic systems, this volume also offers a guide to the mathematical, numerical, and simulation tools of systems analysis. Suitable for advanced undergraduates and graduate-level industrial engineers and management science majors, it proposes modeling systems in terms of their simulation, regardless of whether simulation is employed for analysis. Beginning with a view of the conditions that permit a mathematical-numerical analysis, the text explores Poisson and renewal processes, Markov chains in discrete and continuous time, se

  15. Exergy Analysis of Operating Lignite Fired Thermal Power Plant

    Directory of Open Access Journals (Sweden)

    K. Murugesan

    2009-01-01

    Full Text Available The energy assessment must be made through the energy quantity as well as the quality. But the usual energy analysisevaluates the energy generally on its quantity only. However, the exergy analysis assesses the energy on quantity as well asthe quality. The aim of the exergy analysis is to identify the magnitudes and the locations of real energy losses, in order toimprove the existing systems, processes or components. The present paper deals with an exergy analysis performed on anoperating 50MWe unit of lignite fired steam power plant at Thermal Power Station-I, Neyveli Lignite Corporation Limited,Neyveli, Tamil Nadu, India. The exergy losses occurred in the various subsystems of the plant and their components havebeen calculated using the mass, energy and exergy balance equations. The distribution of the exergy losses in several plantcomponents during the real time plant running conditions has been assessed to locate the process irreversibility. The Firstlaw efficiency (energy efficiency and the Second law efficiency (exergy efficiency of the plant have also been calculated.The comparison between the energy losses and the exergy losses of the individual components of the plant shows that themaximum energy losses of 39% occur in the condenser, whereas the maximum exergy losses of 42.73% occur in the combustor.The real losses of energy which has a scope for the improvement are given as maximum exergy losses that occurredin the combustor.

  16. Assessment of dermal hazard from acid burns with fire retardant garments in a full-size simulation of an engulfment flash fire.

    Science.gov (United States)

    Mackay, Christopher E; Vivanco, Stephanie N; Yeboah, George; Vercellone, Jeff

    2016-09-01

    There have been concerns that fire-derived acid gases could aggravate thermal burns for individuals wearing synthetic flame retardant garments. A comparative risk assessment was performed on three commercial flame retardant materials with regard to relative hazards associated with acidic combustion gases to skin during a full engulfment flash fire event. The tests were performed in accordance with ASTM F1930 and ISO 13506: Standard Test Method for Evaluation of Flame Resistant Clothing for Protection against Fire Simulations Using an Instrumented Manikin. Three fire retardant textiles were tested: an FR treated cotton/nylon blend, a low Protex(®) modacrylic blend, and a medium Protex(®) modacrylic blend. The materials, in the form of whole body coveralls, were subjected to propane-fired flash conditions of 84kW/m(2) in a full sized simulator for a duration of either 3 or 4s. Ion traps consisting of wetted sodium carbonate-impregnated cellulose in Teflon holders were placed on the chest and back both above and under the standard undergarments. The ion traps remained in position from the time of ignition until 5min post ignition. Results indicated that acid deposition did increase with modacrylic content from 0.9μmol/cm(2) for the cotton/nylon, to 12μmol/cm(2) for the medium modacrylic blend. The source of the acidity was dominated by hydrogen chloride. Discoloration was inversely proportional to the amount of acid collected on the traps. A risk assessment was performed on the potential adverse impact of acid gases on both the skin and open wounds. The results indicated that the deposition and dissolution of the acid gases in surficial fluid media (perspiration and blood plasma) resulted in an increase in acidity, but not sufficient to induce irritation/skin corrosion or to cause necrosis in open third degree burns.

  17. Impacts of global open-fire aerosols on direct radiative, cloud and surface-albedo effects simulated with CAM5

    Science.gov (United States)

    Jiang, Yiquan; Lu, Zheng; Liu, Xiaohong; Qian, Yun; Zhang, Kai; Wang, Yuhang; Yang, Xiu-Qun

    2016-11-01

    Aerosols from open-land fires could significantly perturb the global radiation balance and induce climate change. In this study, Community Atmosphere Model version 5 (CAM5) with prescribed daily fire aerosol emissions is used to investigate the spatial and seasonal characteristics of radiative effects (REs, relative to the case of no fires) of open-fire aerosols including black carbon (BC) and particulate organic matter (POM) from 2003 to 2011. The global annual mean RE from aerosol-radiation interactions (REari) of all fire aerosols is 0.16 ± 0.01 W m-2 (1σ uncertainty), mainly due to the absorption of fire BC (0.25 ± 0.01 W m-2), while fire POM induces a small effect (-0.05 and 0.04 ± 0.01 W m-2 based on two different methods). Strong positive REari is found in the Arctic and in the oceanic regions west of southern Africa and South America as a result of amplified absorption of fire BC above low-level clouds, in general agreement with satellite observations. The global annual mean RE due to aerosol-cloud interactions (REaci) of all fire aerosols is -0.70 ± 0.05 W m-2, resulting mainly from the fire POM effect (-0.59 ± 0.03 W m-2). REari (0.43 ± 0.03 W m-2) and REaci (-1.38 ± 0.23 W m-2) in the Arctic are stronger than in the tropics (0.17 ± 0.02 and -0.82 ± 0.09 W m-2 for REari and REaci), although the fire aerosol burden is higher in the tropics. The large cloud liquid water path over land areas and low solar zenith angle of the Arctic favor the strong fire aerosol REaci (up to -15 W m-2) during the Arctic summer. Significant surface cooling, precipitation reduction and increasing amounts of low-level cloud are also found in the Arctic summer as a result of the fire aerosol REaci based on the atmosphere-only simulations. The global annual mean RE due to surface-albedo changes (REsac) over land areas (0.03 ± 0.10 W m-2) is small and statistically insignificant and is mainly due to the fire BC-in-snow effect (0.02 W m-2) with the maximum albedo effect

  18. Enforcing fire safety in the catering industry : an economic analysis.

    NARCIS (Netherlands)

    Suurmond, Guido

    2008-01-01

    What is an effective and efficient enforcement policy for fire safety in the catering industry? When and why is an informal, cooperative enforcement style through warnings, persuasion and advice (a so called compliance strategy) effective in inducing compliance with the fire safety regulation? The s

  19. Two-stage numerical simulation for temperature profile in furnace of tangentially fired pulverized coal boiler

    Institute of Scientific and Technical Information of China (English)

    ZHOU Nai-jun; XU Qiong-hui; ZHOU Ping

    2005-01-01

    Considering the fact that the temperature distribution in furnace of a tangential fired pulverized coal boiler is difficult to be measured and monitored, two-stage numerical simulation method was put forward. First, multi-field coupling simulation in typical work conditions was carried out off-line with the software CFX-4.3, and then the expression of temperature profile varying with operating parameter was obtained. According to real-time operating parameters, the temperature at arbitrary point of the furnace can be calculated by using this expression. Thus the temperature profile can be shown on-line and monitoring for combustion state in the furnace is realized. The simul-ation model was checked by the parameters measured in an operating boiler, DG130-9.8/540. The maximum of relative error is less than 12% and the absolute error is less than 120 ℃, which shows that the proposed two-stage simulation method is reliable and able to satisfy the requirement of industrial application.

  20. QTL analysis of the genetic architecture determining resistance to fire blight in an apple progeny

    NARCIS (Netherlands)

    Calenge, F.; Drouet, D.; Weg, van de W.E.; Brisset, M.N.; Paulin, J.P.; Durel, C.E.

    2004-01-01

    Fire blight, caused by the bacterial pathogen Erwinia amylovora, is one of the most destructive diseases of apple (Malus x domestica). In order to analyse the genetic determinism of resistance to fire blight in apple, a quantitative trait analysis (QTL) approach was used. A F1 progeny of 164 individ

  1. The Computational Fluid Dynamic Simulation of Fire Evacuation from the Student Dormitory

    Directory of Open Access Journals (Sweden)

    Teeranon Saelao

    2012-01-01

    Full Text Available Problem statement: The aim of this research is to investigate the fire evacuation problem from the student dormitory by using the Numerical method. The Fire Dynamics Simulator Software was used in the research with the evacuation function (FDS + Evac.. The problem under investigation concerns the building that has the open-air centre. The characteristics of the building are included with 5 floors, 2 open-air fire escape stairs located at 2 sides of the building. In addition, there is a single exit to the outside of the building and the sprinkler system is not installed inside the building. Approach: The simulation was designed to study the problem that has a source of fire occurring at the room closed to the open-air stair. The stairs will be severely affected by the smoke. The experimentation's are composed of 4 cases, which are (1 the first case assumes the true size of the door is 1 m (2 the second case assumes the true size of the door is 1 m and the smoke barrier is installed at the beam located before the stair entrance (3 the third case assumes the true size of the door is 2 m and (4 the fourth case assumes the true size of the door is 2 m and the smoke barrier is installed. Results: The results are shown that the escape time from the building with the 1 m door is 465 sec and the 2 m door is 265 sec. The time differentiation between the 1 m door and the 2 m door is 200 sec. The reason is the waiting occurred at the entrance if the smoke barrier is not installed. In this case, the smoke in the stairs without a smoke barrier installation has more than the smoke in case if the smoke barrier is installed. However, this research collected the data of the gas volume and found that the gas volume is not yet harmful to human life but the gas can be an obstacle to evacuation in the building that has an open-air centre. Conclusion: For safety reasons, the building’s user should improve the door size and install the smoke barrier at 2 sides of the

  2. Assessment of fire emission inventories during the South American Biomass Burning Analysis (SAMBBA) experiment

    Science.gov (United States)

    Pereira, Gabriel; Siqueira, Ricardo; Rosário, Nilton E.; Longo, Karla L.; Freitas, Saulo R.; Cardozo, Francielle S.; Kaiser, Johannes W.; Wooster, Martin J.

    2016-06-01

    Fires associated with land use and land cover changes release large amounts of aerosols and trace gases into the atmosphere. Although several inventories of biomass burning emissions cover Brazil, there are still considerable uncertainties and differences among them. While most fire emission inventories utilize the parameters of burned area, vegetation fuel load, emission factors, and other parameters to estimate the biomass burned and its associated emissions, several more recent inventories apply an alternative method based on fire radiative power (FRP) observations to estimate the amount of biomass burned and the corresponding emissions of trace gases and aerosols. The Brazilian Biomass Burning Emission Model (3BEM) and the Fire Inventory from NCAR (FINN) are examples of the first, while the Brazilian Biomass Burning Emission Model with FRP assimilation (3BEM_FRP) and the Global Fire Assimilation System (GFAS) are examples of the latter. These four biomass burning emission inventories were used during the South American Biomass Burning Analysis (SAMBBA) field campaign. This paper analyzes and inter-compared them, focusing on eight regions in Brazil and the time period of 1 September-31 October 2012. Aerosol optical thickness (AOT550 nm) derived from measurements made by the Moderate Resolution Imaging Spectroradiometer (MODIS) operating on board the Terra and Aqua satellites is also applied to assess the inventories' consistency. The daily area-averaged pyrogenic carbon monoxide (CO) emission estimates exhibit significant linear correlations (r, p > 0.05 level, Student t test) between 3BEM and FINN and between 3BEM_ FRP and GFAS, with values of 0.86 and 0.85, respectively. These results indicate that emission estimates in this region derived via similar methods tend to agree with one other. However, they differ more from the estimates derived via the alternative approach. The evaluation of MODIS AOT550 nm indicates that model simulation driven by 3BEM and FINN

  3. Meteosat SEVIRI Fire Radiative Power (FRP products from the Land Surface Analysis Satellite Applications Facility (LSA SAF – Part 1: Algorithms, product contents and analysis

    Directory of Open Access Journals (Sweden)

    M. J. Wooster

    2015-06-01

    information together with the per-pixel uncertainty metrics. Using scene simulations and analysis of real SEVIRI data, including from a period of Meteosat-8 "special operations", we describe some of the sensor and data pre-processing characteristics influencing fire detection and FRP uncertainty. We show that the FTA algorithm is able to discriminate actively burning fires covering down to 10−4 of a pixel, and is more sensitive to fire than algorithms used within many other widely exploited active fire products. We also find that artefacts arising from the digital filtering and geometric resampling strategies used to generate level 1.5 SEVIRI data can significantly increase FRP uncertainties in the SEVIRI active fire products, and recommend that the processing chains used for the forthcoming Meteosat Third Generation attempt to minimise the impact of these types of operations. Finally, we illustrate the information contained within the current Meteosat FRP-PIXEL and FRP-GRID products, providing example analyses for both individual fires and multi-year regional-scale fire activity. A companion paper (Roberts et al., 2015 provides a full product performance evaluation for both products, along with examples of their use for prescribing fire smoke emissions within atmospheric modelling components of the Copernicus Atmosphere Monitoring Service (CAMS.

  4. The Application of Numerical Simulation in Bus Fire Investigations%数值模拟在公交车火灾调查中的应用

    Institute of Scientific and Technical Information of China (English)

    祝飞; 毕昆

    2012-01-01

    对公交车火灾进行数值模拟可以给火灾调查提供证据支持。通过描述火源、公交车的结构以及可燃物的属性,重构某火灾过程。通过比较模拟结果和火灾现场的调查结果,可以很好地预测火势的发展和烟气运动,解释人员伤亡的原因,为整个火灾重构的进一步研究打下基础,同时,指出火灾模拟在实际火灾场景调查中的应用价值。%Numerical simulation in a bus fire may provide the evidence for fire investigations. may reconstruct a fire process, explain fire development, smoke movement and personal death Numerical simulation through source, the configuration of the bus and property of fuel. The simulation results, compared with the describing fire fire site recon- naissanee results, demonstrates a good prediction of fire development and smoke movement, explains the cause of death, which will lay down a good foundation for further study in fire reconstruction of the whole fire and provide application of fire simulation into actual fire scene investigation.

  5. Investigation of Lab Fire Prevention Management System of Combining Root Cause Analysis and Analytic Hierarchy Process with Event Tree Analysis

    Directory of Open Access Journals (Sweden)

    Cheng-Chan Shih

    2016-01-01

    Full Text Available This paper proposed a new approach, combining root cause analysis (RCA, analytic hierarchy process (AHP, and event tree analysis (ETA in a loop to systematically evaluate various laboratory safety prevention strategies. First, 139 fire accidents were reviewed to identify the root causes and draw out prevention strategies. Most fires were caused due to runaway reactions, operation error and equipment failure, and flammable material release. These mostly occurred in working places of no prompt fire protection. We also used AHP to evaluate the priority of these strategies and found that chemical fire prevention strategy is the most important control element, and strengthening maintenance and safety inspection intensity is the most important action. Also together with our surveys results, we proposed that equipment design is also critical for fire prevention. Therefore a technical improvement was propounded: installing fire detector, automatic sprinkler, and manual extinguisher in the lab hood as proactive fire protections. ETA was then used as a tool to evaluate laboratory fire risks. The results indicated that the total risk of a fire occurring decreases from 0.0351 to 0.0042 without/with equipment taking actions. Establishing such system can make Environment, Health and Safety (EH&S office not only analyze and prioritize fire prevention policies more practically, but also demonstrate how effective protective equipment improvement can achieve and the probabilities of the initiating event developing into a serious accident or controlled by the existing safety system.

  6. Identifying and tracking simulated synaptic inputs from neuronal firing: insights from in vitro experiments.

    Directory of Open Access Journals (Sweden)

    Maxim Volgushev

    2015-03-01

    Full Text Available Accurately describing synaptic interactions between neurons and how interactions change over time are key challenges for systems neuroscience. Although intracellular electrophysiology is a powerful tool for studying synaptic integration and plasticity, it is limited by the small number of neurons that can be recorded simultaneously in vitro and by the technical difficulty of intracellular recording in vivo. One way around these difficulties may be to use large-scale extracellular recording of spike trains and apply statistical methods to model and infer functional connections between neurons. These techniques have the potential to reveal large-scale connectivity structure based on the spike timing alone. However, the interpretation of functional connectivity is often approximate, since only a small fraction of presynaptic inputs are typically observed. Here we use in vitro current injection in layer 2/3 pyramidal neurons to validate methods for inferring functional connectivity in a setting where input to the neuron is controlled. In experiments with partially-defined input, we inject a single simulated input with known amplitude on a background of fluctuating noise. In a fully-defined input paradigm, we then control the synaptic weights and timing of many simulated presynaptic neurons. By analyzing the firing of neurons in response to these artificial inputs, we ask 1 How does functional connectivity inferred from spikes relate to simulated synaptic input? and 2 What are the limitations of connectivity inference? We find that individual current-based synaptic inputs are detectable over a broad range of amplitudes and conditions. Detectability depends on input amplitude and output firing rate, and excitatory inputs are detected more readily than inhibitory. Moreover, as we model increasing numbers of presynaptic inputs, we are able to estimate connection strengths more accurately and detect the presence of connections more quickly. These results

  7. Comparative study of experiment and numerical analysis of secondary disasters induced by wood fire in tunnel

    Institute of Scientific and Technical Information of China (English)

    CHENG Cai-xia; ZHOU Xin-quan

    2010-01-01

    Studied the changes of heat physical parameters, gas concentration of O2, CO,CH4 and H2, and temperature through full scale wood fire experiments in a tunnel and simulation by FLUNET, a kind of computational fluid dynamics software. The results show that the wood fire experiment and simulation are both oxygen-enriched combustions,which show that the simulation results coincide with the experiment. The results also prove that it is difficult for oxygen-enriched combustion to cause secondary disasters. Some suggestions were put forward to prevent the occurrence of secondary disasters effectively.

  8. Computer-simulation study on fire behaviour in the ventilated cavity of ventilated façade systems

    Directory of Open Access Journals (Sweden)

    Giraldo María P.

    2013-11-01

    Full Text Available Fire spread through the façades is widely recognized as one of the fastest pathways of fire spreading in the buildings. Fire may spread through the façade in different ways depending on the type of façade system and on the elements and materials from which it is constructed. Ventilated façades are multilayer systems whose main feature is the creation of an air chamber of circulating air between the original building wall and the external cladding. The “chimney effect” in the air cavity is a mechanism that improves the façade's thermal behaviour and avoids the appearance of moisture from rain or condensation. However, in a event of fire, it may contribute to the quickest spreading of fire, representing a significant risk to the upper floors of a building. This study deals with some aspects of fire propagation through the ventilated cavity in ventilated façade systems. Also we review the provisions stipulated by the Spanish building code (Código Técnico de la Edificación, CTE [1] to avoid fire spread outside the building. The results highlight the importance of the use of proper fire barriers to ensure the compartmentalization of the ventilated cavity, as well as the use of non-combustible thermal insulation materials, among others. In addition, based on the results, it might be considered that the measures stipulated by the CTE are insufficient to limit the risks associated with this kind of façades systems. The study has been performed using field models of computational fluid-dynamics. In particular, the Fire Dynamics Simulator (FDS software has been used to numerically solve the mathematical integration models.

  9. Hydrocarbon characterization experiments in fully turbulent fires : results and data analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Suo-Anttila, Jill Marie; Blanchat, Thomas K.

    2011-03-01

    As the capabilities of numerical simulations increase, decision makers are increasingly relying upon simulations rather than experiments to assess risks across a wide variety of accident scenarios including fires. There are still, however, many aspects of fires that are either not well understood or are difficult to treat from first principles due to the computational expense. For a simulation to be truly predictive and to provide decision makers with information which can be reliably used for risk assessment the remaining physical processes must be studied and suitable models developed for the effects of the physics. The model for the fuel evaporation rate in a liquid fuel pool fire is significant because in well-ventilated fires the evaporation rate largely controls the total heat release rate from the fire. This report describes a set of fuel regression rates experiments to provide data for the development and validation of models. The experiments were performed with fires in the fully turbulent scale range (> 1 m diameter) and with a number of hydrocarbon fuels ranging from lightly sooting to heavily sooting. The importance of spectral absorption in the liquid fuels and the vapor dome above the pool was investigated and the total heat flux to the pool surface was measured. The importance of convection within the liquid fuel was assessed by restricting large scale liquid motion in some tests. These data sets provide a sound, experimentally proven basis for assessing how much of the liquid fuel needs to be modeled to enable a predictive simulation of a fuel fire given the couplings between evaporation of fuel from the pool and the heat release from the fire which drives the evaporation.

  10. Crown Fire Potential

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — Crown fire potential was modeled using FlamMap, an interagency fire behavior mapping and analysis program that computes potential fire behavior characteristics. The...

  11. Simulating boreal forest carbon dynamics after stand-replacing fire disturbance: insights from a global process-based vegetation model

    Science.gov (United States)

    Yue, C.; Ciais, P.; Luyssaert, S.; Cadule, P.; Harden, J.; Randerson, J.; Bellassen, V.; Wang, T.; Piao, S.L.; Poulter, B.; Viovy, N.

    2013-01-01

    Stand-replacing fires are the dominant fire type in North American boreal forests. They leave a historical legacy of a mosaic landscape of different aged forest cohorts. This forest age dynamics must be included in vegetation models to accurately quantify the role of fire in the historical and current regional forest carbon balance. The present study adapted the global process-based vegetation model ORCHIDEE to simulate the CO2 emissions from boreal forest fire and the subsequent recovery after a stand-replacing fire; the model represents postfire new cohort establishment, forest stand structure and the self-thinning process. Simulation results are evaluated against observations of three clusters of postfire forest chronosequences in Canada and Alaska. The variables evaluated include: fire carbon emissions, CO2 fluxes (gross primary production, total ecosystem respiration and net ecosystem exchange), leaf area index, and biometric measurements (aboveground biomass carbon, forest floor carbon, woody debris carbon, stand individual density, stand basal area, and mean diameter at breast height). When forced by local climate and the atmospheric CO2 history at each chronosequence site, the model simulations generally match the observed CO2 fluxes and carbon stock data well, with model-measurement mean square root of deviation comparable with the measurement accuracy (for CO2 flux ~100 g C m−2 yr−1, for biomass carbon ~1000 g C m−2 and for soil carbon ~2000 g C m−2). We find that the current postfire forest carbon sink at the evaluation sites, as observed by chronosequence methods, is mainly due to a combination of historical CO2 increase and forest succession. Climate change and variability during this period offsets some of these expected carbon gains. The negative impacts of climate were a likely consequence of increasing water stress caused by significant temperature increases that were not matched by concurrent increases in precipitation. Our simulation

  12. Simulating boreal forest carbon dynamics after stand-replacing fire disturbance: insights from a global process-based vegetation model

    Science.gov (United States)

    Yue, C.; Ciais, P.; Luyssaert, S.; Cadule, P.; Harden, J.; Randerson, J.; Bellassen, V.; Wang, T.; Piao, S. L.; Poulter, B.; Viovy, N.

    2013-12-01

    Stand-replacing fires are the dominant fire type in North American boreal forests. They leave a historical legacy of a mosaic landscape of different aged forest cohorts. This forest age dynamics must be included in vegetation models to accurately quantify the role of fire in the historical and current regional forest carbon balance. The present study adapted the global process-based vegetation model ORCHIDEE to simulate the CO2 emissions from boreal forest fire and the subsequent recovery after a stand-replacing fire; the model represents postfire new cohort establishment, forest stand structure and the self-thinning process. Simulation results are evaluated against observations of three clusters of postfire forest chronosequences in Canada and Alaska. The variables evaluated include: fire carbon emissions, CO2 fluxes (gross primary production, total ecosystem respiration and net ecosystem exchange), leaf area index, and biometric measurements (aboveground biomass carbon, forest floor carbon, woody debris carbon, stand individual density, stand basal area, and mean diameter at breast height). When forced by local climate and the atmospheric CO2 history at each chronosequence site, the model simulations generally match the observed CO2 fluxes and carbon stock data well, with model-measurement mean square root of deviation comparable with the measurement accuracy (for CO2 flux ~100 g C m-2 yr-1, for biomass carbon ~1000 g C m-2 and for soil carbon ~2000 g C m-2). We find that the current postfire forest carbon sink at the evaluation sites, as observed by chronosequence methods, is mainly due to a combination of historical CO2 increase and forest succession. Climate change and variability during this period offsets some of these expected carbon gains. The negative impacts of climate were a likely consequence of increasing water stress caused by significant temperature increases that were not matched by concurrent increases in precipitation. Our simulation results

  13. An enhanced real-time forest fire assessment algorithm based on video by using texture analysis

    Directory of Open Access Journals (Sweden)

    Gudikandhula Narasimha Rao

    2016-09-01

    Full Text Available As the human technology moved further, the risk of natural and man induced sudden damage increase exponentially. One of the most dangerous disasters is fire. In addition to its direct danger on human's lives, fire consumes forests where trees that provide humans with oxygen are destroyed. Every year, the large number of wildfires happening all over the world they burn forested lands, causing adverse ecological and social impacts. Early warning and immediate responses are the only ways to avoid such type of disasters. This work describes a naïve method is used to detect flames in forest by using a Spatio Wildfire Prediction and Monitoring System (SWPMS. Basically, the fired information retrieving from regions by using background subtraction and colour analysis. The fire behaviour is modelled by texture analysis using computer vision systems. The Central Server should receives fired regions from the volunteer's smart phone and use fired location coordinates, different angles of smart phone receives fired locations based on Google Earth API. Finally, Kalman filter estimator computes the position vector of a moving object. Antennas or Satellite systems are grasping information from fire regions then GIS will be analyzed those regions and send alert to local peoples of forest regions and NDRF team.

  14. Analysis of the Large Urban Fire Environment. Part 1. Theory

    Science.gov (United States)

    1982-07-01

    and thus affect the rate of airflow into the fire. However, only a few observations support that hypothesis (Carrier, Fendell , and Feldman, 1982...Fire Protection Association, Boston, Massachusetts, 1951. Carrier, G. F., F. E. Fendell , and P. S. Feldman, Firestorms, TRW Space and Technology Group...Grounds, M4D Dr. Francis E. Fendell 21005 (1) RI/1038 TRW Director, U.S. Army Ballistic One Space Park Research Laboratory Redondo Beach, CA 90278 (1

  15. Accurate Assessment of RSET for Building Fire Based on Engineering Calculation and Numerical Simulation

    Directory of Open Access Journals (Sweden)

    Yan Zhenzhen

    2016-01-01

    Full Text Available In order to obtain the Required Safety Egress Time (RSET accurately, traditional engineering calculation method of evacuation time has been optimized in this paper. Several principles and fact situations were used to optimize the method, such as detecting principle of the fire detecting system, reaction characteristics of staff being in urgent situation, evacuating queuing theory, building structure and the plugging at the porthole. Taking a three-storey KTV as an example, two methods are used to illustrate the reliability and scientific reasonability of the calculation result. The result is deduced by comparing the error (less than 2% at an allowable range between two results. One result is calculated by a modified method of engineering calculation method, and the other one is given based on a Steering model of Pathfinder evacuation simulation software. The optimized RSET has a good feasibility and Accuracy.

  16. Numerical simulation of NOx formation in a cyclone-opposed coal-fired utility boiler

    Institute of Scientific and Technical Information of China (English)

    LI Fang-qin; REN Jian-xing; WEI Dun-song

    2005-01-01

    In this paper, FLUENT software was used to simulate the burning process in a utility boiler. Chose the kinetics/diffusion-limited as combustion model, two-compet-ingrates as devolatjlization model, RNG k-εmodel as viscous model, and PDF model as combustion turbulent flow model. Numerical calculation of NOx formation in a 330 MW cyclone-opposed coal-fired utility boiler with 32 double air registers was done. The distribution characteristics of temperature, NOx and oxygen concentration in furnace were studied. They were symmetrically distributed in furnace. In the combustion area, temperature and NOx concentration are high, while oxygen concentration is low. Temperature and NOx concentration are declined gradually along with furnace height, while oxygen concentration is raised. The higher the temperature is and the greater the excess air coefficient is, the more NOx formation.

  17. 高层住宅建筑火灾人员疏散仿真研究%Study on evacuation simulation of high-rise residential building fire

    Institute of Scientific and Technical Information of China (English)

    邢志祥; 唐永; 高文莉

    2012-01-01

    基于高层建筑火灾的严重危害,本文在具体分析阐述我国目前高层住宅建筑的户型设计现状后,以长沙市某高层塔式住宅建筑为研究对象,利用人员疏散软件Building EXODUS( V4.06版)和烟气模拟软件CFAST对发生火灾后建筑物的人员疏散和烟气流动情况仿真模拟.研究表明,逃生楼梯的设计位置对高层塔式住宅的人员疏散效率影响较大;在发生紧急情况后,事前是否进行过疏散演习和事中的人工干预引导疏散对保障高层住宅建筑火灾居民的生命安全尤为重要;高层住宅建筑火灾,起火楼层越底,伤亡越大.%Based on the serious danger of high-rise building fire, in this paper the passenger evacuation and the smoke movement of a high-rise tower partment structural fire in Changsha were simulated using evacuation software Building EXODUS V4. 06 and fire simulation software CFAST after the analysis of different design of high-rise partment building at present particularly. The computation results showed that the location of evacuation staircase has a significant effect to the evacuation efficiency and preventative evacuation practice and manual intervention are propitious to passenger evacuation. It is also indicated that the higher floors fire is more dangerous than the lower floors fire.

  18. Research on solar aided coal-fired power generation system and performance analysis

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Integrating solar power utilization systems with coal-fired power units, the solar aided coal-fired power generation (SACPG) shows a significant prospect for the large-scale utilization of solar energy and energy saving of thermal power units. The methods and mechanism of system integration were studied. The parabolic trough solar collectors were used to collect solar energy and the integration scheme of SACPG system was determined considering the matching of working fluid flows and energy flows. The thermodynamic characteristics of solar thermal power generation and their effects on the performance of thermal power units were studied, and based on this the integration and optimization model of system structure and parameters were built up. The integration rules and coupling mecha- nism of SACPG systems were summarized in accordance with simulation results. The economic analysis of this SACPG system showed that the solar LEC of a typical SACPG system, considering CO2 avoidance, is 0.098 $/kW·h, lower than that of SEGS, 0.14 $/kW·h.

  19. 某类重特大火灾数值模拟研究%Numerical Simulation for Special-typed Big Fires

    Institute of Scientific and Technical Information of China (English)

    袁杰; 申世飞

    2011-01-01

    Causes and sites of several fires occnrred in a bar, the Dancer King Club in Shenzhen City, and the Forever-joy Latin Club in Fujian Province are similar. Heavy casualties caused by fire in the short time. Therefore, it is worthwhile to study fire prevention and controlmeasures. The advantage of the FDS software is taken to construct a fire model of the bar. The evacuation simulation parameter can be rationally set through the rational analysis involving on site situation of porsons. By seltting the appropriate fire scens according to the actual fires, the software can analyze the parameter change of the beat radiation, smoke temperature, smoke toxicity, and smoke visthifity in older to figure out the available evacuation time. Combined with CFE software to simulate the evacuation process, fire consequence analysis has been carried out in accordance with the different fuel types, fire facilities, and the number of evacuated persons. Fuel analysis results show that renvation of polyurethane foam sound-absorbing cotton weakens fire technology and is direct cause of the fire spreading speed. The materials can produce large amounts of toxic smoke and cause casualties in a short period. The simulation results of diffierent fire-fighting facilities reflect the important role played by automatic fire-fighting facilities. The quiek response sprinkler beads should be promotod for the sprinkler system in public amenities. The reason for large number of casualties is that automatic fire-fighting facilities not been installed in accordance with national standards. The quantitative analysis of the anticipated casalties in the different number of evacuated persons has proved that the fixed member of fire control manager in the public amenities has a great significant. The results can be used to analyze the cauls of fires and fire preventiou measures.%某酒吧火灾、深圳舞王俱乐部火灾和福建长乐拉丁酒吧火灾的发生场所和火灾原因类似,且短时间

  20. Fire-Needle Moxibustion for the Treatment of Knee Osteoarthritis: A Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Yidan Wang

    2016-01-01

    Full Text Available Objectives. The aim of this study was to evaluate the effectiveness of fire-needle moxibustion as an intervention in the treatment of knee osteoarthritis (KOA. Methods. An updated meta-analysis of randomized controlled trials (RCTs on fire-needle moxibustion in treating KOA was conducted by searching PubMed, Embase, the Cochrane Library, Web of Science, Wanfang database, and the Chinese Medical Database (CNKI since their inception through March 2016. The meta-analysis was performed using RevMan 5.3. Results. Thirteen RCTs were identified in the systematic study which consisted of 1179 participants. Fire-needle moxibustion treatment group had a statistical significance on recovery rate as well as recovery and marked-improvement rate compared with control group. Subgroup analysis indicated that there was significant difference between fire-needle moxibustion group and control group. However, GRADE analysis indicated that the quality of evidence for all outcomes was relatively low. Only two of 13 studies reported adverse reactions (difficulty in movement and intolerance of cold. Conclusion. This meta-analysis suggests that fire-needle moxibustion is more effective than control group in symptom management of KOA. Further high quality trials should be conducted to evaluate the effectiveness of fire-needle moxibustion on KOA.

  1. Power converter simulation and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ghazy, M.A.

    1989-01-01

    There has been a great deal of progress made in computer aided design and analysis in the power electronic field. Many of the simulation packages are inefficient and time consuming in simulating switching converters. This thesis proposes an efficient, simple, general simulation approach to simulate any power converter with less computation time and space requirements on computer. In this approach the equations of power converters are formulated using network topology. In this thesis several procedures have been explained for the steady-state computation of power electronic circuits. Also, the steady-state analyses have been accomplished by a new technique called Fourier series method. For a complete system consisting of converters, filters, and electric machines, the simulation is complicated if a frequency domain technique is used. This thesis introduces a better technique which decouples the system into subsystems and simulates it in the time domain. The design of power converters using optimization techniques is presented in this thesis. Finally, the theory of Variable Structured Systems has been applied to power converters. Sliding mode control for DC-DC and DC-AC power converters is introduced as a tool to accomplish desired characteristics.

  2. On the performance of voltage stepping for the simulation of adaptive, nonlinear integrate-and-fire neuronal networks.

    Science.gov (United States)

    Kaabi, Mohamed Ghaith; Tonnelier, Arnaud; Martinez, Dominique

    2011-05-01

    In traditional event-driven strategies, spike timings are analytically given or calculated with arbitrary precision (up to machine precision). Exact computation is possible only for simplified neuron models, mainly the leaky integrate-and-fire model. In a recent paper, Zheng, Tonnelier, and Martinez (2009) introduced an approximate event-driven strategy, named voltage stepping, that allows the generic simulation of nonlinear spiking neurons. Promising results were achieved in the simulation of single quadratic integrate-and-fire neurons. Here, we assess the performance of voltage stepping in network simulations by considering more complex neurons (quadratic integrate-and-fire neurons with adaptation) coupled with multiple synapses. To handle the discrete nature of synaptic interactions, we recast voltage stepping in a general framework, the discrete event system specification. The efficiency of the method is assessed through simulations and comparisons with a modified time-stepping scheme of the Runge-Kutta type. We demonstrated numerically that the original order of voltage stepping is preserved when simulating connected spiking neurons, independent of the network activity and connectivity.

  3. A trend analysis of global fire activity. Is it land use or climate the main driver?

    Science.gov (United States)

    Bistinas, Ioannis; Oom, Duarte; Silva, Joao M. N.; Lopez-Saldaña, Gerardo; Pereira, Jose M. C.

    2016-04-01

    We perform a global trend analysis of active fire counts at 0.5o spatial resolution, using 156 months (January 2001 - December 2013) of MODIS Climate Modelling Grid data (TERRA). We use the Contextual Mann-Kendall (CMK) test to assess the statistical significance at cell level and found that 13% of the global land area displays statistically significant active fire count trends, with a slight predominance of negative trends (50.63% of the total significant cells). We perform the same trend analysis with the unexplained variability (residuals) between active fires and the Fire Weather Index (FWI) that is used as a proxy for climate. There is agreement between the main patterns from the trend analysis coming from the residuals and the active fire trends, implying that the main contemporary fire trends are not climate driven. Spatially coherent patches with significant trends were found in all continents (with the obvious exception of Antarctica). The majority of significant trends occur in areas of high fire incidence, and both increasing and decreasing trends appear to be associated with land use change processes. The analysis reveals large negative trends at the Sahel and between Russia and Kazakhstan, whereas a massive and coherent positive trend appears in southeastern Asia. Smaller patches of positive trends appear in southeastern United States and in Mexico, as well as in Brazil and between Argentina and Paraguay, and in Asia in India. There are also negative trends in Brazil, Argentina and in Australia. The study highlights the land use activities as the main driver of these trends, but also the need for data driven analyses and longer time series for future studies in order to gain better knowledge on fire occurrence.

  4. Investigation of Lab Fire Prevention Management System of Combining Root Cause Analysis and Analytic Hierarchy Process with Event Tree Analysis

    OpenAIRE

    Cheng-Chan Shih; Horng, Richard S.; Shin-Ku Lee

    2016-01-01

    This paper proposed a new approach, combining root cause analysis (RCA), analytic hierarchy process (AHP), and event tree analysis (ETA) in a loop to systematically evaluate various laboratory safety prevention strategies. First, 139 fire accidents were reviewed to identify the root causes and draw out prevention strategies. Most fires were caused due to runaway reactions, operation error and equipment failure, and flammable material release. These mostly occurred in working places of no prom...

  5. Impacts of global open-fire aerosols on direct radiative, cloud and surface-albedo effects simulated with CAM5

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Yiquan; Lu, Zheng; Liu, Xiaohong; Qian, Yun; Zhang, Kai; Wang, Yuhang; Yang, Xiu-Qun

    2016-11-29

    Aerosols from open-land fires could significantly perturb the global radiation balance and induce climate change. In this study, Community Atmosphere Model version 5 (CAM5) with prescribed daily fire aerosol emissions is used to investigate the spatial and seasonal characteristics of radiative effects (REs, relative to the case of no fires) of open-fire aerosols including black carbon (BC) and particulate organic matter (POM) from 2003 to 2011. The global annual mean RE from aerosol–radiation interactions (REari) of all fire aerosols is 0.16 ± 0.01 W m-2 (1σ uncertainty), mainly due to the absorption of fire BC (0.25 ± 0.01 W m-2), while fire POM induces a small effect (-0.05 and 0.04 ± 0.01 W m-2 based on two different methods). Strong positive REari is found in the Arctic and in the oceanic regions west of southern Africa and South America as a result of amplified absorption of fire BC above low-level clouds, in general agreement with satellite observations. The global annual mean RE due to aerosol–cloud interactions (REaci) of all fire aerosols is -0.70 ± 0.05 W m-2, resulting mainly from the fire POM effect (-0.59 ± 0.03 W m-2). REari (0.43 ± 0.03 W m-2) and REaci (-1.38 ± 0.23 W m-2) in the Arctic are stronger than in the tropics (0.17 ± 0.02 and -0.82 ± 0.09 W m-2 for REari and REaci), although the fire aerosol burden is higher in the tropics. The large cloud liquid water path over land areas and low solar zenith angle of the Arctic favor the strong fire aerosol REaci (up to -15 Wm-2) during the Arctic summer. Significant surface cooling, precipitation reduction and increasing amounts of low-level cloud are also found in the Arctic summer as a result of the fire aerosol REaci based on the atmosphere-only simulations. The global annual mean RE due to surface-albedo changes (REsac) over land areas (0.03 ± 0.10 W m-2) is small

  6. Intercomparison of cloud model simulations of Arctic mixed-phase boundary layer clouds observed during SHEBA/FIRE-ACE

    Directory of Open Access Journals (Sweden)

    Mikhail Ovchinnikov

    2011-06-01

    Full Text Available An intercomparison of six cloud-resolving and large-eddy simulation models is presented. This case study is based on observations of a persistent mixed-phase boundary layer cloud gathered on 7 May, 1998 from the Surface Heat Budget of Arctic Ocean (SHEBA and First ISCCP Regional Experiment - Arctic Cloud Experiment (FIRE-ACE. Ice nucleation is constrained in the simulations in a way that holds the ice crystal concentration approximately fixed, with two sets of sensitivity runs in addition to the baseline simulations utilizing different specified ice nucleus (IN concentrations. All of the baseline and sensitivity simulations group into two distinct quasi-steady states associated with either persistent mixed-phase clouds or all-ice clouds after the first few hours of integration, implying the existence of multiple equilibria. These two states are associated with distinctly different microphysical, thermodynamic, and radiative characteristics. Most but not all of the models produce a persistent mixed-phase cloud qualitatively similar to observations using the baseline IN/crystal concentration, while small increases in the IN/crystal concentration generally lead to rapid glaciation and conversion to the all-ice state. Budget analysis indicates that larger ice deposition rates associated with increased IN/crystal concentrations have a limited direct impact on dissipation of liquid in these simulations. However, the impact of increased ice deposition is greatly enhanced by several interaction pathways that lead to an increased surface precipitation flux, weaker cloud top radiative cooling and cloud dynamics, and reduced vertical mixing, promoting rapid glaciation of the mixed-phase cloud for deposition rates in the cloud layer greater than about 1-2x10-5 g kg-1 s-1. These results indicate the critical importance of precipitation-radiative-dynamical interactions in simulating cloud phase, which have been neglected in previous fixed-dynamical parcel

  7. Modeling and numerical analysis of granite rock specimen under mechanical loading and fire

    Institute of Scientific and Technical Information of China (English)

    Luc Leroy Ngueyep. Mambou; Joseph Ndop; Jean-Marie Bienvenu Ndjaka

    2015-01-01

    The effect of ISO 834 fire on the mechanical properties of granite rock specimen submitted to uniaxial loading is numerically investigated. Based on Newton’s second law, the rate-equation model of granite rock specimen under mechanical load and fire is established. The effect of heat treatment on the me-chanical performance of granite is analyzed at the center and the ends of specimen. At the free end of granite rock specimen, it is shown that from 20 ?C to 500 ?C, the internal stress and internal strain are weak; whereas above 500 ?C, they start to increase rapidly, announcing the imminent collapse. At the center of specimen, the analysis of the internal stress and internal strain reveals that the fire reduces the mechanical performance of granite significantly. Moreover, it is found that after 3 min of exposure to fire, the mechanical energy necessary to fragment the granite can be reduced up to 80%.

  8. The Cosmic Baryon Cycle and Galaxy Mass Assembly in the FIRE Simulations

    CERN Document Server

    Anglés-Alcázar, Daniel; Kereš, Dušan; Hopkins, Philip F; Quataert, Eliot; Murray, Norman

    2016-01-01

    We use cosmological simulations from the FIRE (Feedback In Realistic Environments) project to study the baryon cycle and galaxy mass assembly for central galaxies in the halo mass range $M_{\\rm halo} \\sim 10^{10} - 10^{13} M_{\\odot}$. By tracing cosmic inflows, galactic outflows, gas recycling, and merger histories, we quantify the contribution of physically distinct sources of material to galaxy growth. We show that in situ star formation fueled by fresh accretion dominates the early growth of galaxies of all masses, while the re-accretion of gas previously ejected in galactic winds often dominates the gas supply for a large portion of every galaxy's evolution. Externally processed material contributes increasingly to the growth of central galaxies at lower redshifts. This includes stars formed ex situ and gas delivered by mergers, as well as smooth intergalactic transfer of gas from other galaxies, an important but previously under-appreciated growth mode. By $z=0$, wind transfer, i.e. the exchange of gas b...

  9. Giant clumps in the FIRE simulations: a case study of a massive high-redshift galaxy

    CERN Document Server

    Oklopcic, Antonija; Feldmann, Robert; Keres, Dusan; Faucher-Giguere, Claude-Andre; Murray, Norman

    2016-01-01

    The morphology of massive star-forming galaxies at high redshift is often dominated by giant clumps of mass ~10^8-10^9 Msun and size ~100-1000 pc. Previous studies have proposed that giant clumps might have an important role in the evolution of their host galaxy, particularly in building the central bulge. However, this depends on whether clumps live long enough to migrate from their original location in the disc or whether they get disrupted by their own stellar feedback before reaching the centre of the galaxy. We use cosmological hydrodynamical simulations from the FIRE (Feedback in Realistic Environments) project that implement explicit treatments of stellar feedback and ISM physics to study the properties of these clumps. We follow the evolution of giant clumps in a massive (stellar mass ~10^10.8 Msun at z=1), discy, gas-rich galaxy from redshift z>2 to z=1. Even though the clumpy phase of this galaxy lasts over a gigayear, individual gas clumps are short-lived, with mean lifetime of massive clumps of ~2...

  10. Simulation of emission performance and combustion efficiency in biomass fired circulating fluidized bed combustors

    Energy Technology Data Exchange (ETDEWEB)

    Gungor, Afsin [Nigde University, Faculty of Engineering and Architecture, Department of Mechanical Engineering, 51100 Nigde (Turkey)

    2010-04-15

    In this study, the combustion efficiency and the emission performance of biomass fired CFBs are tested via a previously published 2D model [Gungor A. Two-dimensional biomass combustion modeling of CFB. Fuel 2008; 87: 1453-1468.] against two published comprehensive data sets. The model efficiently simulates the outcome with respect to the excess air values, which is the main parameter that is verified. The combustion efficiency of OC changes between 82.25 and 98.66% as the excess air increases from 10 to 116% with the maximum error of about 8.59%. The rice husk combustion efficiency changes between 98.05 and 97.56% as the bed operational velocity increases from 1.2 to 1.5 m s{sup -1} with the maximum error of about 7.60%. CO and NO{sub x} emissions increase with increasing bed operational velocity. Increasing excess air results in slightly higher levels of NO{sub x} emission. A significant amount of combustion occurs in the upper zone due to the high volatile content of the biomass fuels. (author)

  11. Analysis of pressurization of plutonium oxide storage vials during a postulated fire

    Energy Technology Data Exchange (ETDEWEB)

    Laurinat, J.; Kesterson, M.; Hensel, S.

    2015-02-10

    The documented safety analysis for the Savannah River Site evaluates the consequences of a postulated 1000 °C fire in a glovebox. The radiological dose consequences for a pressurized release of plutonium oxide powder during such a fire depend on the maximum pressure that is attained inside the oxide storage vial. To enable evaluation of the dose consequences, pressure transients and venting flow rates have been calculated for exposure of the storage vial to the fire. A standard B vial with a capacity of approximately 8 cc was selected for analysis. The analysis compares the pressurization rate from heating and evaporation of moisture adsorbed onto the plutonium oxide contents of the vial with the pressure loss due to venting of gas through the threaded connection between the vial cap and body. Tabulated results from the analysis include maximum pressures, maximum venting velocities, and cumulative vial volumes vented during the first 10 minutes of the fire transient. Results are obtained for various amounts of oxide in the vial, various amounts of adsorbed moisture, different vial orientations, and different surface fire exposures.

  12. Experimental and numerical analysis of the cooling performance of water spraying systems during a fire.

    Directory of Open Access Journals (Sweden)

    YaoHan Chen

    Full Text Available The water spray systems are effective protection systems in the confined or unconfined spaces to avoid the damage to building structures since the high temperature when fires occur. NFPA 15 and 502 have suggested respectively that the factories or vehicle tunnels install water spray systems to protect the machinery and structures. This study discussed the cooling effect of water spray systems in experimental and numerical analyses. The actual combustion of woods were compared with the numerical simulations. The results showed that although the flame continued, the cooling effects by water spraying process within 120 seconds were obvious. The results also indicated that the simulation results of the fifth version Fire Dynamics Simulator (FDS overestimated the space temperature before water spraying in the case of the same water spray system.

  13. Experimental and numerical analysis of the cooling performance of water spraying systems during a fire.

    Science.gov (United States)

    Chen, YaoHan; Su, ChungHwei; Tseng, JoMing; Li, WunJie

    2015-01-01

    The water spray systems are effective protection systems in the confined or unconfined spaces to avoid the damage to building structures since the high temperature when fires occur. NFPA 15 and 502 have suggested respectively that the factories or vehicle tunnels install water spray systems to protect the machinery and structures. This study discussed the cooling effect of water spray systems in experimental and numerical analyses. The actual combustion of woods were compared with the numerical simulations. The results showed that although the flame continued, the cooling effects by water spraying process within 120 seconds were obvious. The results also indicated that the simulation results of the fifth version Fire Dynamics Simulator (FDS) overestimated the space temperature before water spraying in the case of the same water spray system.

  14. Analysis of a Series of Electromagnetic Launcher Firings,

    Science.gov (United States)

    1987-06-01

    m I current in the rallgun circuit, A 10 current In the railgun circuit at the Instant of crowbarring of the capacitor bank, A I1 current passing...the results obtained from the digitiser. The power source (1,51 for the electromagnetic launcher used in the RPIP series consisted of a capacitor bank...0.3 pH. In all of the firings reported here the capacitor bank was charged to 6.00 t 0.03 kV. The cadmium-copper rails used in the RAPID railgun were

  15. Using Distributed, Integrated Hydrological Models to Simulate Water Balance Changes at the Hillslope and Catchment Scale Due to Fire Disturbances

    Science.gov (United States)

    Atchley, A. L.; Coon, E.; Trader, L.; Middleton, R. S.; Painter, S. L.; Kikinzon, E.

    2015-12-01

    Catastrophic wildfires have increased worldwide due in part to previous fire suppression efforts, but also climate change. These wildfires dramatically alter ecosystem structure resulting in lasting changes to hydrological characteristics including surface runoff and subsurface water storage. Most notably fire results in the removal of forest ground cover as well as much, if not all, of the forest vegetation that is responsible for precipitation interception and transpiration from the soil. The presence of ground cover is associated with high porosity, surface roughness and infiltration rates, which can contribute to greater soil water recharge. Modeling the hydrological changes due to fire requires representation of the vegetation changes along with near surface soil characteristics, particularly ground cover. Moreover, the coupled nature of surface and subsurface flow necessitates an integrated representation of variably saturated subsurface flow and overland flow to capture infiltration-limited runoff. Here pre- and post-catastrophic fire data collected from Bandelier National Monument is used to characterize ground cover and vegetation conditions used in coupled surface subsurface hydrologic models. This data is also used to develop appropriate representations of litter layers in the models. Changes in hydrologic regimes at the hillslope and catchment scale are simulated in response to measured precipitation events. Differences in both runoff generation and soil water storage are then described along a continuum of burn severity.

  16. Large eddy simulation of fire-induced buoyancy driven plume dispersion in an urban street canyon under perpendicular wind flow.

    Science.gov (United States)

    Hu, L H; Huo, R; Yang, D

    2009-07-15

    The dispersion of fire-induced buoyancy driven plume in and above an idealized street canyon of 18 m (width) x 18 m (height) x 40 m (length) with a wind flow perpendicular to its axis was investigated by Fire Dynamics Simulator (FDS), Large Eddy Simulation (LES). Former studies, such as that by Oka [T.R. Oke, Street design and urban canopy layer climate, Energy Build. 11 (1988) 103-113], Gayev and Savory [Y.A. Gayev, E. Savory, Influence of street obstructions on flow processes within street canyons. J. Wind Eng. Ind. Aerodyn. 82 (1999) 89-103], Xie et al. [S. Xie, Y. Zhang, L. Qi, X. Tang, Spatial distribution of traffic-related pollutant concentrations in street canyons. Atmos. Environ. 37 (2003) 3213-3224], Baker et al. [J. Baker, H. L. Walker, X. M. Cai, A study of the dispersion and transport of reactive pollutants in and above street canyons--a large eddy simulation, Atmos. Environ. 38 (2004) 6883-6892] and Baik et al. [J.-J. Baik, Y.-S. Kang, J.-J. Kim, Modeling reactive pollutant dispersion in an urban street canyon, Atmos. Environ. 41 (2007) 934-949], focus on the flow pattern and pollutant dispersion in the street canyon with no buoyancy effect. Results showed that with the increase of the wind flow velocity, the dispersion pattern of a buoyant plume fell into four regimes. When the wind flow velocity increased up to a certain critical level, the buoyancy driven upward rising plume was re-entrained back into the street canyon. This is a dangerous situation as the harmful fire smoke will accumulate to pollute the environment and thus threaten the safety of the people in the street canyon. This critical re-entrainment wind velocity, as an important parameter to be concerned, was further revealed to increase asymptotically with the heat/buoyancy release rate of the fire.

  17. Physics-Based Simulator for NEO Exploration Analysis & Simulation

    Science.gov (United States)

    Balaram, J.; Cameron, J.; Jain, A.; Kline, H.; Lim, C.; Mazhar, H.; Myint, S.; Nayar, H.; Patton, R.; Pomerantz, M.; Quadrelli, M.; Shakkotai, P.; Tso, K.

    2011-01-01

    As part of the Space Exploration Analysis and Simulation (SEAS) task, the National Aeronautics and Space Administration (NASA) is using physics-based simulations at NASA's Jet Propulsion Laboratory (JPL) to explore potential surface and near-surface mission operations at Near Earth Objects (NEOs). The simulator is under development at JPL and can be used to provide detailed analysis of various surface and near-surface NEO robotic and human exploration concepts. In this paper we describe the SEAS simulator and provide examples of recent mission systems and operations concepts investigated using the simulation. We also present related analysis work and tools developed for both the SEAS task as well as general modeling, analysis and simulation capabilites for asteroid/small-body objects.

  18. Giant clumps in the FIRE simulations: a case study of a massive high-redshift galaxy

    Science.gov (United States)

    Oklopčić, Antonija; Hopkins, Philip F.; Feldmann, Robert; Kereš, Dušan; Faucher-Giguère, Claude-André; Murray, Norman

    2017-02-01

    The morphology of massive star-forming galaxies at high redshift is often dominated by giant clumps of mass ˜108-109 M⊙ and size ˜100-1000 pc. Previous studies have proposed that giant clumps might have an important role in the evolution of their host galaxy, particularly in building the central bulge. However, this depends on whether clumps live long enough to migrate from their original location in the disc or whether they get disrupted by their own stellar feedback before reaching the centre of the galaxy. We use cosmological hydrodynamical simulations from the FIRE (Feedback in Realistic Environments) project which implement explicit treatments of stellar feedback and interstellar medium physics to study the properties of these clumps. We follow the evolution of giant clumps in a massive (M* ˜ 1010.8 M⊙ at z = 1), discy, gas-rich galaxy from redshift z ≳ 2 to z = 1. Even though the clumpy phase of this galaxy lasts over a gigayear, individual gas clumps are short-lived, with mean lifetime of massive clumps of ˜20 Myr. During that time, they turn between 0.1 per cent and 20 per cent of their gas into stars before being disrupted, similar to local giant molecular clouds. Clumps with M ≳ 107 M⊙ account for ˜20 per cent of the total star formation in the galaxy during the clumpy phase, producing ˜1010 M⊙ of stars. We do not find evidence for net inward migration of clumps within the galaxy. The number of giant clumps and their mass decrease at lower redshifts, following the decrease in the overall gas fraction and star formation rate.

  19. FDS软件对LNG储罐泄漏火灾后果的模拟%FDS software simulation for fire consequences of LNG storage tank leaks

    Institute of Scientific and Technical Information of China (English)

    狄建华; 陈方兼

    2013-01-01

    采用FDS火灾模型软件分析了在设定的LNG火灾场景下火焰的发展规律,以广州某燃气公司3个LNG储罐中的中间储罐为研究对象,设定火灾场景,建立LNG储罐区细化模型,对火势总体情况、温度场测量点、云图动画、等值面动画、热辐射以及烟气危险区域进行模拟分析.结果表明:火灾发生时,罐区总控室附近的温度远高于危险判断值,火灾发生30 s、110 s时的危险区域范围变化较大,烟气层温度高于180℃及烟气危险等区域均出现在储罐与总控室之间的有限范围内,在人员疏散过程中应远离面向火源侧的建筑墙面.%FDS fire modeling software has been used to analyze development law of the flame in the LNG fire scenarios set. The middle one of 3 LNG storage tanks of a gas company in Guangzhou was taken as a study object to set up fire scenarios and build a refined model for LNG storage tankfarms, so as to carry out simulation analysis on overall fire situation, temperature field measuring point, cloud picture animation, isosurface animation, thermal radiation and hazardous flue gas areas. The results display that when a fire breaks out, the temperature in the vicinity of the tankfarm control room will be much higher than the danger judgement value, scope of hazardous area will follow a large change after 30 s and 110 s and the areas for smoke layer temperature higher than 180℃ and flue gas hazard will be within the limited range between the storage tank and control room. Therefore, the wall of a building facing the side of the fire source shall be kept away in the process of evacuation.

  20. Numerical simulation of fire development in a single compartment based on cone calorimeter experiments

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The burning characteristics of several kinds of wood and polyurethane materials have been studied using cone calorimeter (CONE2A). A new and simple ignition criterion, heat release rate model and mass loss rate model are proposed based on experiments. Combined with these models, the zone-model of fire can be used to predict fire development in a single compartment according to the species of combustibles, their quantities and distribution. Calculated results show that this method is simple and feasible.

  1. An analysis of the chemical processes in the smoke plume from a savanna fire

    Science.gov (United States)

    Trentmann, JöRg; Yokelson, Robert J.; Hobbs, Peter V.; Winterrath, Tanja; Christian, Theodore J.; Andreae, Meinrat O.; Mason, Sherri A.

    2005-06-01

    Photochemistry in young plumes from vegetation fires significantly transforms the initial fire emissions within the first hour after the emissions are injected into the atmosphere. Here we present an investigation of field measurements obtained in a smoke plume from a prescribed savanna fire during the SAFARI 2000 field experiment using a detailed photochemical box-dilution model. The dilution used in the model simulations was constrained by measurements of chemically passive tracers (e.g., CO) near and downwind of the fire. The emissions of the dominant carbonaceous compounds, including oxygenated ones, were taken into account. The field measurements revealed significant production of ozone and acetic acid in the gas phase. The photochemical model simulations also predict ozone production, but significantly less than the measurements. The underestimation of the ozone production in the model simulations is likely caused by shortcomings of our current understanding of ozone photochemistry under the polluted conditions in this young smoke plume. Several potential reasons for this discrepancy are discussed. One possible cause could be the neglect of unmeasured emissions or surface reactions of NO2 with methanol or other hydrocarbons. In contrast to the field measurements, no significant production of acetic acid was simulated by the model. We know of no gas-phase reactions that cause the production of acetic acid on the timescale considered here. Though many processes were well-simulated by the model, there is a need for further research on some key photochemical processes within young plumes from biomass burning and the potential interactions between gas and the particulate phases. These fundamental photochemical processes may also be of importance in other polluted environments.

  2. Analysis of the Earthquake Impact towards water-based fire extinguishing system

    Science.gov (United States)

    Lee, J.; Hur, M.; Lee, K.

    2015-09-01

    Recently, extinguishing system installed in the building when the earthquake occurred at a separate performance requirements. Before the building collapsed during the earthquake, as a function to maintain a fire extinguishing. In particular, the automatic sprinkler fire extinguishing equipment, such as after a massive earthquake without damage to piping also must maintain confidentiality. In this study, an experiment installed in the building during the earthquake, the water-based fire extinguishing saw grasp the impact of the pipe. Experimental structures for water-based fire extinguishing seismic construction step by step, and then applied to the seismic experiment, the building appears in the extinguishing of the earthquake response of the pipe was measured. Construction of acceleration caused by vibration being added to the size and the size of the displacement is measured and compared with the data response of the pipe from the table, thereby extinguishing water piping need to enhance the seismic analysis. Define the seismic design category (SDC) for the four groups in the building structure with seismic criteria (KBC2009) designed according to the importance of the group and earthquake seismic intensity. The event of a real earthquake seismic analysis of Category A and Category B for the seismic design of buildings, the current fire-fighting facilities could have also determined that the seismic performance. In the case of seismic design categories C and D are installed in buildings to preserve the function of extinguishing the required level of seismic retrofit design is determined.

  3. Fire safety

    Energy Technology Data Exchange (ETDEWEB)

    Keski-Rahkonen, O.; Bjoerkman, J.; Hostikka, S.; Mangs, J. [VTT Building Technology, Espoo (Finland); Huhtanen, R. [VTT Energy, Espoo (Finland); Palmen, H.; Salminen, A.; Turtola, A. [VTT Automation, Espoo (Finland)

    1998-07-01

    According to experience and probabilistic risk assessments, fires present a significant hazard in a nuclear power plant. Fires may be initial events for accidents or affect safety systems planned to prevent accidents and to mitigate their consequences. The project consists of theoretical work, experiments and simulations aiming to increase the fire safety at nuclear power plants. The project has four target areas: (1) to produce validated models for numerical simulation programmes, (2) to produce new information on the behavior of equipment in case of fire, (3) to study applicability of new active fire protecting systems in nuclear power plants, and (4) to obtain quantitative knowledge of ignitions induced by important electric devices in nuclear power plants. These topics have been solved mainly experimentally, but modelling at different level is used to interpret experimental data, and to allow easy generalisation and engineering use of the obtained data. Numerical fire simulation has concentrated in comparison of CFD modelling of room fires, and fire spreading on cables on experimental data. So far the success has been good to fair. A simple analytical and numerical model has been developed for fire effluents spreading beyond the room of origin in mechanically strongly ventilated compartments. For behaviour of equipment in fire several full scale and scaled down calorimetric experiments were carried out on electronic cabinets, as well as on horizontal and vertical cable trays. These were carried out to supply material for CFD numerical simulation code validation. Several analytical models were developed and validated against obtained experimental results to allow quick calculations for PSA estimates as well as inter- and extrapolations to slightly different objects. Response times of different commercial fire detectors were determined for different types of smoke, especially emanating from smoldering and flaming cables to facilitate selection of proper detector

  4. Using thermal analysis to evaluate the fire effects on organic matter content of Andisols

    Directory of Open Access Journals (Sweden)

    J. Neris

    2013-09-01

    Full Text Available Soil organic compounds play a relevant role in aggregate stability and thus, in the susceptibility of soils to erosion. Thermal analysis (N2 and air and chemical oxidation techniques (dichromate and permanganate oxidation were used to evaluate the effects of a forest fire on the organic matter of Andisols. Both thermal analysis and chemical methods showed a decrease in the organic matter content and an increase in the recalcitrance of the remaining organic compounds in the burned zones. Thermal analysis indicated an increase in the thermal stability of the organic compounds of fire-affected soils and a lower content of both labile and recalcitrant pools as a consequence of the fire. However, this decrease was relatively higher in the labile pool and lower in the recalcitrant one, indicative of an increase in the recalcitrance of the remaining organic compounds. Apparently, black carbon did not burn under our experimental conditions. Under N2, the results showed a lower labile and a higher recalcitrant and refractory contents in burned and some unburned soils, possibly due to the lower decomposition rate under N2 flux. Thermal analysis using O2 and the chemical techniques showed a positive relation, but noticeable differences in the total amount of the labile pool. Thermal analysis methods provide direct quantitative information useful to characterize the soil organic matter quality and to evaluate the effects of fire on soils.

  5. A simulation study on the effects of dendritic morphology on layer V PFC pyramidal cell firing behavior

    Directory of Open Access Journals (Sweden)

    Maria Psarrou

    2014-03-01

    Full Text Available The majority of neuronal cells found in the cerebral cortex are pyramidal neurons. Their function has been associated with higher cognitive and emotional functions. Pyramidal neurons have a characteristic structure, consisting of a triangular shaped soma whereon descend two extended and complex dendritic trees, and a long bifurcated axon. All the morphological components of the pyramidal neurons exhibit significant variability across different brain areas and layers. Pyramidal cells receive numerous synaptic inputs along their structure, integration of which in space and in time generates local dendritic spikes that shape their firing pattern. In addition, synaptic integration is influenced by voltage-gated and ion channels, which are expressed in a large repertoire by pyramidal neurons. Electrophysiological categories of pyramidal cells can be established, based on the action potential frequency, generated from a fixed somatic stimulus: (1 cells that fire repetitive action potentials (Regular Spiking – RS, (2 cells that fire clusters of 2 – 5 action potentials with short ISIs (Intrinsic Bursting – IB, and (3 cells that fire in repetitive clusters of 2 – 5 action potentials with short ISIs (Repetitive Oscillatory Bursts – ROB. In vitro and in silico scientific studies, correlate the firing patterns of the pyramidal neurons to their morphological features. This study provides a quantitatively analysis via compartmental neuronal modelling of the effects of dendritic morphology and distribution and concentration of ionic mechanisms, along the basal and/or apical dendrites on the firing behavior of a 112-set of layer V rat PFC pyramidal cells. We focus on how particular morphological and passive features of the dendritic trees shape the neuronal firing patterns. Our results suggest that specific morphological parameters (such as total length, volume and branch number can discriminate the cells as RS or IB, regardless of what is the

  6. Simulation of a combined space and water heating system firing pellet fuel for commercial/residential application

    Energy Technology Data Exchange (ETDEWEB)

    Clements, B.R.; Pearson, B.; Hayden, A.C.S. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Energy Technology Centre

    2001-06-01

    Gensym Corporation has developed a real-time dynamic simulator which can test different physical configurations of a variety of commercial or residential combined space heating and domestic hot water systems. This simulator was originally designed to test biomass pellet-fueled stoves, but it can also be applied to more conventional gas and oil fired systems. Each physical configuration can be tested under different operating conditions to determine optimal system design for each unique situation. CANMET Energy Technology Centre is focused on developing advanced residential integrated systems using biomass pellets as a fuel to take advantage of their energy efficiency and the environmental benefits that they offer. High efficiency pellet-fired integrated home energy systems consist of components that can be configured in several ways to suit specific installation needs. The major components of the system are the fuel storage and supply system, the pellet burner, the fuel and ash removal system, the furnace air supply, the exhaust module, boiler, hot water storage tank, forced air fan coil unit and the plate to plate domestic hot water heat exchanger. Many different design and control scenarios were tested using the real-time simulator before developing an optimal arrangement for a specific set of constraints. The simulator proved to be an extremely valuable tool in developing and testing control strategies. 4 refs., 3 figs.

  7. Urban Fire Risk Clustering Method Based on Fire Statistics

    Institute of Scientific and Technical Information of China (English)

    WU Lizhi; REN Aizhu

    2008-01-01

    Fire statistics and fire analysis have become important ways for us to understand the law of fire,prevent the occurrence of fire, and improve the ability to control fire. According to existing fire statistics, the weighted fire risk calculating method characterized by the number of fire occurrence, direct economic losses,and fire casualties was put forward. On the basis of this method, meanwhile having improved K-mean clus-tering arithmetic, this paper established fire dsk K-mean clustering model, which could better resolve the automatic classifying problems towards fire risk. Fire risk cluster should be classified by the absolute dis-tance of the target instead of the relative distance in the traditional cluster arithmetic. Finally, for applying the established model, this paper carded out fire risk clustering on fire statistics from January 2000 to December 2004 of Shenyang in China. This research would provide technical support for urban fire management.

  8. Physicomathematical Simulation Analysis for Small Bullets

    Directory of Open Access Journals (Sweden)

    D. P. Margaris

    2008-01-01

    Full Text Available A full six degrees of freedom (6-DOF flight dynamics model is proposed for the accurate prediction of short and long-range trajectories of small bullets via atmospheric flight to final impact point. The mathematical model is based on the full equations of motion set up in the no-roll body reference frame and is integrated numerically from given initial conditions at the firing site. The projectile maneuvering motion depends on the most significant force and moment variations, in addition to gravity and Magnus effect. The computational flight analysis takes into consideration the Mach number and total angle of attack effects by means of the variable aerodynamic coefficients. For the purposes of the present work, linear interpolation has been applied for aerodynamic coefficients from the official tabulated database. The developed computational method gives satisfactory agreement with published data of verified experiments and computational codes on atmospheric projectile trajectory analysis for various initial firing flight conditions.

  9. Analysis of human reliability in the APS of fire. Application of NUREG-1921; Analisis de Fiabilidad Humana en el APS de Incendios. Aplicacion del NUREG-1921

    Energy Technology Data Exchange (ETDEWEB)

    Perez Torres, J. L.; Celaya Meler, M. A.

    2014-07-01

    An analysis of human reliability in a probabilistic safety analysis (APS) of fire aims to identify, describe, analyze and quantify, in a manner traceable, human actions that can affect the mitigation of an initiating event produced by a fire. (Author)

  10. Numerical simulation and disaster prevention for catastrophic fire airflow of main air-intake belt roadway in coal mine-A case study

    Institute of Scientific and Technical Information of China (English)

    周刚; 程卫民; 张睿; 沈宝堂; 聂文; 张磊; 王昊

    2015-01-01

    Coal mine belt fire develops very rapidly and is difficult to control. If not suppressed quickly, a belt fire could easily lead to airflow disorder and undermine the ventilation system. However, belt fire can be prevented effectively by establishing fire airflow control system. In this work, the 5th belt roadway of Kongzhuang coal mine was taken as the object of investigation, where geometrical models of this roadway were established firstly. Then, based on mathematical model of fire smoke flow, the CO volume fraction, smoke density distribution, air temperature and pollutant velocity vector in the roadway before and after taking airflow control measures were simulated by using Fluent software. It can be known from the simulation that with the normal ventilation status in 5th belt roadway, the countercurrent of smoke does not happen when a fire occurs; the roadway’s section is almost filled with CO at 10 m downstream from the fire source, and with air velocity getting stable gradually, the CO concentration reaches about 15 %. After taking airflow control measures, the effect range of temperature field which are harmful to the miners decreases from 69 m to 30 m; and the distance of the roadway fully filled with CO is 5 m farther than that before taking measures. Finally, according to the numerical simulation results and the actual condition of the belt roadway, the warning and automatic remote airflow control system with short-circuit method for the 5th belt roadway was designed to guarantee the safety production.

  11. Quantitative Analysis of Mixed Halogen Dioxins and Furans in Fire Debris Utilizing Atmospheric Pressure Ionization Gas Chromatography-Triple Quadrupole Mass Spectrometry.

    Science.gov (United States)

    Organtini, Kari L; Myers, Anne L; Jobst, Karl J; Reiner, Eric J; Ross, Brian; Ladak, Adam; Mullin, Lauren; Stevens, Douglas; Dorman, Frank L

    2015-10-20

    Residential and commercial fires generate a complex mixture of volatile, semivolatile, and nonvolatile compounds. This study focused on the semi/nonvolatile components of fire debris to better understand firefighter exposure risks. Using the enhanced sensitivity of gas chromatography coupled to atmospheric pressure ionization-tandem mass spectrometry (APGC-MS/MS), complex fire debris samples collected from simulation fires were analyzed for the presence of potentially toxic polyhalogenated dibenzo-p-dioxins and dibenzofurans (PXDD/Fs and PBDD/Fs). Extensive method development was performed to create multiple reaction monitoring (MRM) methods for a wide range of PXDD/Fs from dihalogenated through hexa-halogenated homologue groups. Higher halogenated compounds were not observed due to difficulty eluting them off the long column used for analysis. This methodology was able to identify both polyhalogenated (mixed bromo-/chloro- and polybromo-) dibenzo-p-dioxins and dibenzofurans in the simulated burn study samples collected, with the dibenzofuran species being the dominant compounds in the samples. Levels of these compounds were quantified as total homologue groups due to the limitations of commercial congener availability. Concentration ranges in household simulation debris were observed at 0.01-5.32 ppb (PXDFs) and 0.18-82.11 ppb (PBDFs). Concentration ranges in electronics simulation debris were observed at 0.10-175.26 ppb (PXDFs) and 0.33-9254.41 ppb (PBDFs). Samples taken from the particulate matter coating the firefighters' helmets contained some of the highest levels of dibenzofurans, ranging from 4.10 ppb to 2.35 ppm. The data suggest that firefighters and first responders at fire scenes are exposed to a complex mixture of potentially hundreds to thousands of different polyhalogenated dibenzo-p-dioxins and dibenzofurans that could negatively impact their health.

  12. Long-term changes in soil erosion due to forest fires. A rainfall simulation approach in Eastern Spain

    Science.gov (United States)

    Cerdà, Artemi; Keesstra, Saskia; Pereira, Paulo; Matrix-Solera, Jorge; Giménez-Morera, Antonio; Úbeda, Xavier; Francos, Marcos; Alcañiz, Meritxell; Jordán, Antonio

    2016-04-01

    Soils are affected by the impacts of wildfires (Dlapa et al., 2013; Pereira et al., 2014; Tsibart et al., 2014; Dlapa et al., 2015, Hedo et al., 2015; Tessler et al., 2015). Soil erosion rates are highly affected by forest fires due to the removal of the above ground vegetation, the heat impact on the soil, the reduction of the organic matter, the ash cover, and the changes introduced by the rainfall on the soil surface (Lasanta and Cerdà, 2005; Mataix-Solera et al., 2011; Novara et al., 2011; Novara et al., 2013; Keesstra et al., 2014; Hedo et al., 2015; Pereira, 2015). Most of the research carried out on forest fire affected land paid attention to the "window of disturbance", which is the period that the soil losses are higher than before the forest fire and that last for few years (Cerdà, 1998a; Cerdà 1998b, Pérez-Cabello et al., 2011; Bodí et al., 2011; Bodí et al., 2012; Pereira et al., 2013: Pereira et al., 2015). However, the spatial and temporal variability of soil erosion is very high as a result of the uneven temporal and spatial distribution of the rainfall (Novara et al., 2011; Bisantino et al., 2015; Gessesse et al., 2015; Ochoa et al., 2015), and the window of disturbance cannot be easily found under natural rainfall. In order to understand the evolution of soil erosion after forest fires it is necessary to monitor fire affected sites over a long period of time, which will enable the assessment of the period affected by the window of disturbance (see Cerdà and Doerr, 2005). However, it is also possible to do measurements and experiments in areas with a different fire history. This will give us information about the temporal changes in soil erosion after forest fire. To reduce the spatial variability of rainfall we can use simulated rainfall that can be applied at multiple site with the same rainfall intensity and duration. For this purpose rainfall simulation can be of great help, in the laboratory (Moreno et al., 2014; Sadegui et al., 2015

  13. Testing of one-inch UF{sub 6} cylinder valves under simulated fire conditions

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, P.G. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    Accurate computational models which predict the behavior of UF{sub 6} cylinders exposed to fires are required to validate existing firefighting and emergency response procedures. Since the cylinder valve is a factor in the containment provided by the UF{sub 6} cylinder, its behavior under fire conditions has been a necessary assumption in the development of such models. Consequently, test data is needed to substantiate these assumptions. Several studies cited in this document provide data related to the behavior of a 1-inch UF{sub 6} cylinder valve in fire situations. To acquire additional data, a series of tests were conducted at the Paducah Gaseous Diffusion Plant (PGDP) under a unique set of test conditions. This document describes this testing and the resulting data.

  14. A Simulation-Based Study of Dorsal Cochlear Nucleus Pyramidal Cell Firing Patterns

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Daliri

    2012-02-01

    Full Text Available A two-variable integrate and fire model is presented to study the role of transient outward potassium currents in producing temporal aspects of dorsal cochlear nucleus (DCN pyramidal cells with different profiles namely the chopper, the pauser and the buildup. This conductance based model is a reduced version of KM-LIF model (Meng & Rinzel, 2010 which captures qualitative firing features of a detailed physiological model (Kanold & Manis, 2000.For our development we benefit from transient potassium currents properties i.e.fast activation and slow inactivation to generate long latency before start of firing.We compare our minimal model outputs in response to a hyperpolarizing stimulus fallowed by a depolarizing one with the data of KM-LIF model.The results conform well to the KM-LIF model with lower complexity.

  15. Energy release from pit fires for producing a fire model. Natural-scale analysis of energy release from pit fires for the purpose of establishing a fire model. Final report; Energiefreisetzung von Grubenbraenden zur Erstellung eines Brandmodell. Untersuchung ueber die Energiefreisetzung von Grubenbraenden im natuerlichen Massstab zur Erstellung eines Brandmodells. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Holke, K.; Michelis, J.

    1996-12-31

    In the context of the research project, measurements were made regarding the energy release in pit fires. The heat flow in fires with standard wood fire objects and in fires on conveyor belts in underground fire sections of the DMT Tremonia experimental pit was measured for this purpose. It was found that the distribution of the mean total heat flow in the roadway crossection depended on the geometric arrangement of the fire object. The belt fire tests carried out have shown that the heat flow depended on the burning behaviour of the belts and with increasing flame propagation on the conveyor belt, the mean heat flow increased. Further, the temperature effects after wood and conveyor belt fires were simulated with the modified `MFIRE` simulation program and were compared with the corresponding experimental results. (orig./MSK) [Deutsch] Im Rahmen des Untersuchungsvorhabens wurden Messungen bezueglich der Energiefreisetzung bei Grubenbraenden durchgefuehrt. Hierzu wurde der Waermefluss bei Braenden mit Standardholzbrandobjekten und bei Foerdergurtbraenden in den untertaegigen Brandstrecken der DMT-Versuchsgrube Tremonia gemessen. Es zeigte sich, dass die Verteilung des mittleren Gesamtwaermeflusses im Streckenquerschnitt von der geometrischen Anordnung des Brandobjektes abhing. Die durchgefuehrten Gurtbrandversuche haben ergeben, dass der Waermefluss vom Brandverhalten der Gurte abhing und mit zunehmender Flammenausbreitung am Foerdergurt der mittlere Waermefluss zunahm. Weiterhin wurden mit dem modifizierten Simulationsprogramm `MFIRE` die Temperaturauswirkungen hinter Holz- und Foerdergurtbraenden simuliert und mit den entsprechenden experimentellen Ergebnissen verglichen. (orig./MSK)

  16. Smoke injection heights from fires in North America: analysis of 5 years of satellite observations

    Directory of Open Access Journals (Sweden)

    M. Val Martin

    2010-02-01

    Full Text Available We analyze an extensive record of aerosol smoke plume heights derived from observations over North America for the fire seasons of 2002 and 2004–2007 made by the Multi-angle Imaging SpectroRadiometer (MISR instrument on board the NASA Earth Observing System Terra satellite. We characterize the magnitude and variability of smoke plume heights for various biomes, and assess the contribution of local atmospheric and fire conditions to this variability. Plume heights are highly variable, ranging from a few hundred meters up to 5000 m above the terrain at the Terra overpass time (11:00–14:00 local time. The largest plumes are found over the boreal region (median values of ~850 m height, 24 km length and 940 m thickness, whereas the smallest plumes are found over cropland and grassland fires in the contiguous US (median values of ~530 m height, 12 km length and 550–640 m thickness. The analysis of plume heights in combination with assimilated meteorological observations from the NASA Goddard Earth Observing System indicates that a significant fraction (4–12% of plumes from fires are injected above the boundary layer (BL, consistent with earlier results for Alaska and the Yukon Territories during summer 2004. Most of the plumes located above the BL (>83% are trapped within stable atmospheric layers. We find a correlation between plume height and the MODerate resolution Imaging Spectroradiometer (MODIS fire radiative power (FRP thermal anomalies associated with each plume. Smoke plumes located in the free troposphere (FT exhibit larger FRP values (1620–1640 MW than those remaining within the BL (174–465 MW. Plumes located in the FT without a stable layer reach higher altitudes and are more spread-out vertically than those associated with distinct stable layers (2490 m height and 2790 m thickness versus 1880 m height and 1800 m thickness. The MISR plume climatology exhibits a well-defined seasonal cycle of plume heights in boreal and

  17. Does Suspected Sleep Disordered Breathing Impact on the Sleep and Performance of Firefighting Volunteers during a Simulated Fire Ground Campaign?

    Science.gov (United States)

    Jay, Sarah M; Smith, Bradley P; Windler, Samantha; Dorrian, Jillian; Ferguson, Sally A

    2016-01-29

    Adequate sleep is fundamental to workplace performance. For volunteer firefighters who work in safety critical roles, poor performance at work can be life threatening. Extended shifts and sleeping conditions negatively impact sleep during multi-day fire suppression campaigns. Having sleep disordered breathing (SDB) could contribute further to sleep deficits. Our aim was to investigate whether those with suspected SDB slept and performed more poorly during a fire ground simulation involving sleep restriction. Participants, n = 20 participated in a 3-day-4-night fire ground simulation. Based on oximetry desaturation index data collected during their participation, participants were retrospectively allocated to either a SDB (n = 8) or a non-SDB group (n = 12). The simulation began with an 8 h Baseline sleep (BL) followed by two nights of restricted (4 h) sleep and an 8 h recovery sleep (R). All sleeps were recorded using a standard electroencephalography (EEG) montage as well as oxygen saturation. During the day, participants completed neurobehavioral (response time, lapses and subjective fatigue) tasks. Mixed effects ANOVA were used to compare differences in sleep and wake variables. Analyses revealed a main effect of group for Total sleep (TST), REM , wake after sleep onset (WASO) and Arousals/h with the SDB group obtaining less TST and REM and greater WASO and Arousals/h. The group × night interaction was significant for N3 with the SDB group obtaining 42 min less during BL. There was a significant main effect of day for RRT, lapses and subjective fatigue and a significant day × group interaction for RRT. Overall, the SDB group slept less, experienced more disturbed sleep and had poorer response time performance, which was exacerbated by the second night of sleep restriction. This could present a safety concern, particularly during longer campaigns and is worthy of further investigation. In addition, we would recommend promotion of awareness of SDB, its symptoms

  18. Does Suspected Sleep Disordered Breathing Impact on the Sleep and Performance of Firefighting Volunteers during a Simulated Fire Ground Campaign?

    Directory of Open Access Journals (Sweden)

    Sarah M. Jay

    2016-01-01

    Full Text Available Adequate sleep is fundamental to workplace performance. For volunteer firefighters who work in safety critical roles, poor performance at work can be life threatening. Extended shifts and sleeping conditions negatively impact sleep during multi-day fire suppression campaigns. Having sleep disordered breathing (SDB could contribute further to sleep deficits. Our aim was to investigate whether those with suspected SDB slept and performed more poorly during a fire ground simulation involving sleep restriction. Participants, n = 20 participated in a 3-day-4-night fire ground simulation. Based on oximetry desaturation index data collected during their participation, participants were retrospectively allocated to either a SDB (n = 8 or a non-SDB group (n = 12. The simulation began with an 8 h Baseline sleep (BL followed by two nights of restricted (4 h sleep and an 8 h recovery sleep (R. All sleeps were recorded using a standard electroencephalography (EEG montage as well as oxygen saturation. During the day, participants completed neurobehavioral (response time, lapses and subjective fatigue tasks. Mixed effects ANOVA were used to compare differences in sleep and wake variables. Analyses revealed a main effect of group for Total sleep (TST, REM , wake after sleep onset (WASO and Arousals/h with the SDB group obtaining less TST and REM and greater WASO and Arousals/h. The group × night interaction was significant for N3 with the SDB group obtaining 42 min less during BL. There was a significant main effect of day for RRT, lapses and subjective fatigue and a significant day × group interaction for RRT. Overall, the SDB group slept less, experienced more disturbed sleep and had poorer response time performance, which was exacerbated by the second night of sleep restriction. This could present a safety concern, particularly during longer campaigns and is worthy of further investigation. In addition, we would recommend promotion of awareness of SDB, its

  19. Evaluation of fire weather forecasts using PM2.5 sensitivity analysis

    Science.gov (United States)

    Balachandran, Sivaraman; Baumann, Karsten; Pachon, Jorge E.; Mulholland, James A.; Russell, Armistead G.

    2017-01-01

    Fire weather forecasts are used by land and wildlife managers to determine when meteorological and fuel conditions are suitable to conduct prescribed burning. In this work, we investigate the sensitivity of ambient PM2.5 to various fire and meteorological variables in a spatial setting that is typical for the southeastern US, where prescribed fires are the single largest source of fine particulate matter. We use the method of principle components regression to estimate sensitivity of PM2.5, measured at a monitoring site in Jacksonville, NC (JVL), to fire data and observed and forecast meteorological variables. Fire data were gathered from prescribed fire activity used for ecological management at Marine Corps Base Camp Lejeune, extending 10-50 km south from the PM2.5 monitor. Principal components analysis (PCA) was run on 10 data sets that included acres of prescribed burning activity (PB) along with meteorological forecast data alone or in combination with observations. For each data set, observed PM2.5 (unitless) was regressed against PCA scores from the first seven principal components (explaining at least 80% of total variance). PM2.5 showed significant sensitivity to PB: 3.6 ± 2.2 μg m-3 per 1000 acres burned at the investigated distance scale of ∼10-50 km. Applying this sensitivity to the available activity data revealed a prescribed burning source contribution to measured PM2.5 of up to 25% on a given day. PM2.5 showed a positive sensitivity to relative humidity and temperature, and was also sensitive to wind direction, indicating the capture of more regional aerosol processing and transport effects. As expected, PM2.5 had a negative sensitivity to dispersive variables but only showed a statistically significant negative sensitivity to ventilation rate, highlighting the importance of this parameter to fire managers. A positive sensitivity to forecast precipitation was found, consistent with the practice of conducting prescribed burning on days when rain

  20. Agent-Based Evacuation Model Incorporating Fire Scene and Building Geometry

    Institute of Scientific and Technical Information of China (English)

    TANG Fangqin; REN Aizhu

    2008-01-01

    A comprehensive description of the key factors affecting evacuations at fire scones is necessary for accurate simulations.An agent-based simulation model which incorporates the fire scene and the building geometry is developed using a fire dynamics simulator (FDS) based on the computational fluid dynamics and geographic information system (GIS) data to model the occupant response.The building entities are generated for FDS simulation while the spatial analysis on GIS data represents the occupant's knowledge of the building.The influence of the fire is based on a hazard assessment of the combustion products.The agent behavior and decisions are affected by environmental features and the fire field.A case study demonstrates that the evacuation model effectively simulates the coexistence and interactions of the major factors including occupants,building geometry,and fire disaster during the evacuation.The results can be used for the assessments of building designs regarding fire safety.

  1. Fire and simulated herbivory have antagonistic effects on resistance of savanna grasslands to alien shrub invasion

    NARCIS (Netherlands)

    te Beest, Mariska; Mpandza, Nokukhanya J.; Olff, Han

    2015-01-01

    Question Resistance of the native community has been identified as an important factor limiting invasion success and invader impact. However, to what extent resistance interacts with disturbance to control invasion success remains unclear. We studied the interaction between biotic resistance, fire a

  2. Forest fire propagation simulations for a risk assessment methodology development for a nuclear power plant

    Directory of Open Access Journals (Sweden)

    Yasushi Okano

    2015-10-01

    Given that this study shows that the maximum height of a flame on a canopy top is close to the range of power line height, a loss of offsite power is recognized as a possible subsequent event during a forest fire.

  3. Training Effectiveness Study of Simulator Usage and Its Impact on Live Fire Armor Gunnery

    Science.gov (United States)

    2014-06-01

    of proficiency. These tasks can range from normal operational level maintenance to the ballet of live-fire. Every crew member has a set of important...requirements for crews based upon experience level do not fit well with the four hour recommended time stated in the manual. As commanders assess their

  4. Advanced concept for damage control : A framework to simulate fire propagation and damage control effects

    NARCIS (Netherlands)

    Gillis, M.P.W.; Keijer, W.; Smit, C.S.

    2003-01-01

    Current damage control procedures are developed on the basis of a long-standing experience. However there are reasons to believe that these procedures do not account for major weapon-induced calamities. Fire fighting after substantial blast and fragmentation damage, due to a weaponhit, is quite beyo

  5. A comparative evaluation of MODIS/ASTER airborne simulator (MASTER) data and burn indices for mapping southern California fires

    Science.gov (United States)

    Harris, S. L.; Hook, S. J.

    2009-12-01

    Large fires occur annually in southern California, producing impacts at a number of scales, from local impacts on vegetation, hydrology and microclimates, to global impacts such as emissions, affecting atmospheric chemistry, air quality, radiation balance and biogeochemical cycling. As a consequence fires are routinely mapped using various sensors and burn indices. However, the indices employed for mapping these fires have not been developed and optimized for mapping southern California burned surfaces. Therefore, this study utilizes the high spatial and spectral resolution imagery from the MODIS/ASTER airborne simulator (MASTER) to identify the most effective bands and indices specifically for burned area mapping of the southern California region. The fire perimeter is based on the Burned Area Reflectance Classification (BARC) map created by the United States Forest Service (USFS), Remote Sensing Applications Center (RSAC) and a supervised classification which defines the burned and unburned regions. A separability index is employed to identify the bands and indices that can best distinguish between classes. The results identify a range of well performing indices, such as the Normalized Burn Ratio (NBR) and the Vegetation Index based on mid-infrared spectral region (VI3), and some poor performing indices, such as the Global Environment Monitoring Index (GEMI) and the Burned Area Index (BAI). Additionally this study highlights the indices that perform better over certain vegetation types. These results are useful for understanding the application of remotely sensed data for mapping burned surfaces. Improved burned area mapping capabilities are essential for informing land managers when identifying regions susceptible to hazards (such as debris and flood flows) and for deciding where to allocate time and resources in recovery efforts. Additionally, these results can be used to validate other sensors that are used to map burned surfaces on greater spatial and

  6. Fire Hazard Analysis for the Cold Vacuum Drying facility (CVD) Facility

    CERN Document Server

    Singh, G

    2000-01-01

    The CVDF is a nonreactor nuclear facility that will process the Spent Nuclear Fuels (SNF) presently stored in the 105-KE and 105-KW SNF storage basins. Multi-canister overpacks (MCOs) will be loaded (filled) with K Basin fuel transported to the CVDF. The MCOs will be processed at the CVDF to remove free water from the fuel cells (packages). Following processing at the CVDF, the MCOs will be transported to the CSB for interim storage until a long-term storage solution can be implemented. This operation is expected to start in November 2000. A Fire Hazard Analysis (FHA) is required for all new facilities and all nonreactor nuclear facilities, in accordance with U.S. Department of Energy (DOE) Order 5480.7A, Fire Protection. This FHA has been prepared in accordance with DOE 5480.7A and HNF-PRO-350, Fire Hazard Analysis Requirements. Additionally, requirements or criteria contained in DOE, Richland Operations Office (RL) RL Implementing Directive (RLID) 5480.7, Fire Protection, or other DOE documentation are cite...

  7. Improved simulation of fire-vegetation interactions in the Land surface Processes and eXchanges dynamic global vegetation model (LPX-Mv1)

    Science.gov (United States)

    Kelley, D. I.; Harrison, S. P.; Prentice, I. C.

    2014-10-01

    The Land surface Processes and eXchanges (LPX) model is a fire-enabled dynamic global vegetation model that performs well globally but has problems representing fire regimes and vegetative mix in savannas. Here we focus on improving the fire module. To improve the representation of ignitions, we introduced a reatment of lightning that allows the fraction of ground strikes to vary spatially and seasonally, realistically partitions strike distribution between wet and dry days, and varies the number of dry days with strikes. Fuel availability and moisture content were improved by implementing decomposition rates specific to individual plant functional types and litter classes, and litter drying rates driven by atmospheric water content. To improve water extraction by grasses, we use realistic plant-specific treatments of deep roots. To improve fire responses, we introduced adaptive bark thickness and post-fire resprouting for tropical and temperate broadleaf trees. All improvements are based on extensive analyses of relevant observational data sets. We test model performance for Australia, first evaluating parameterisations separately and then measuring overall behaviour against standard benchmarks. Changes to the lightning parameterisation produce a more realistic simulation of fires in southeastern and central Australia. Implementation of PFT-specific decomposition rates enhances performance in central Australia. Changes in fuel drying improve fire in northern Australia, while changes in rooting depth produce a more realistic simulation of fuel availability and structure in central and northern Australia. The introduction of adaptive bark thickness and resprouting produces more realistic fire regimes in Australian savannas. We also show that the model simulates biomass recovery rates consistent with observations from several different regions of the world characterised by resprouting vegetation. The new model (LPX-Mv1) produces an improved simulation of observed

  8. Smoke injection heights from fires in North America: analysis of 5 years of satellite observations

    Directory of Open Access Journals (Sweden)

    M. Val Martin

    2009-09-01

    Full Text Available We analyze a multi-year record of aerosol smoke plume heights derived from observations over North America made by the Multi-angle Imaging SpectroRadiometer (MISR instrument on board the NASA Earth Observing System Terra satellite. We characterize the magnitude and variability of smoke plume heights for various biomes, and assess the contribution of local atmospheric and fire conditions to this variability. Plume heights are highly variable, ranging from a few hundred meters up to 5000 m above the terrain at the Terra overpass time (11:00–14:00 local time. The largest plumes are found over the boreal region (median values of ∼850 m height, 24 km length and 940 m thickness, whereas the smallest plumes are found over cropland and grassland fires in the contiguous US (median values of ∼530 m height, 12 km length and 550–640 m thickness. The analysis of plume heights in combination with assimilated meteorological observations from the NASA Goddard Earth Observing System indicates that a significant fraction (4–12% of plumes from fires are injected above the boundary layer (BL, consistent with earlier results for Alaska and the Yukon Territories during summer 2004. Most of the plumes located above the BL (>83% are trapped within stable atmospheric layers. We find a correlation between plume height and the MODerate resolution Imaging Spectroradiometer (MODIS fire radiative power (FRP thermal anomalies associated with each plume. Smoke plumes located in the free troposphere (FT exhibit larger FRP values (1620–1640 MW than those remaining within the BL (174–465 MW. Plumes located in the FT without a stable layer reach higher altitudes and are more spread-out vertically than those associated with distinct stable layers (2490 m height and 2790 m thickness versus 1880 m height and 1800 thickness. The MISR plume climatology exhibits a well-defined seasonal cycle of plume heights in boreal and temperate biomes, with greater heights during June

  9. Simulation modeling and analysis with Arena

    CERN Document Server

    Altiok, Tayfur

    2007-01-01

    Simulation Modeling and Analysis with Arena is a highly readable textbook which treats the essentials of the Monte Carlo discrete-event simulation methodology, and does so in the context of a popular Arena simulation environment.” It treats simulation modeling as an in-vitro laboratory that facilitates the understanding of complex systems and experimentation with what-if scenarios in order to estimate their performance metrics. The book contains chapters on the simulation modeling methodology and the underpinnings of discrete-event systems, as well as the relevant underlying probability, statistics, stochastic processes, input analysis, model validation and output analysis. All simulation-related concepts are illustrated in numerous Arena examples, encompassing production lines, manufacturing and inventory systems, transportation systems, and computer information systems in networked settings.· Introduces the concept of discrete event Monte Carlo simulation, the most commonly used methodology for modeli...

  10. THERMAL ANALYSIS OF A 9975 PACKAGE IN A FACILITY FIRE ACCIDENT

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, N.

    2011-02-14

    Surplus plutonium bearing materials in the U.S. Department of Energy (DOE) complex are stored in the 3013 containers that are designed to meet the requirements of the DOE standard DOE-STD-3013. The 3013 containers are in turn packaged inside 9975 packages that are designed to meet the NRC 10 CFR Part 71 regulatory requirements for transporting the Type B fissile materials across the DOE complex. The design requirements for the hypothetical accident conditions (HAC) involving a fire are given in 10 CFR 71.73. The 9975 packages are stored at the DOE Savannah River Site in the K-Area Material Storage (KAMS) facility for long term of up to 50 years. The design requirements for safe storage in KAMS facility containing multiple sources of combustible materials are far more challenging than the HAC requirements in 10 CFR 71.73. While the 10 CFR 71.73 postulates an HAC fire of 1475 F and 30 minutes duration, the facility fire calls for a fire of 1500 F and 86 duration. This paper describes a methodology and the analysis results that meet the design limits of the 9975 component and demonstrate the robustness of the 9975 package.

  11. Fire Risk Assessment and Its Economic Loss Estimation in Tehran Subway, Applying Event Tree Analysis

    Directory of Open Access Journals (Sweden)

    Sedigheh Atrkar Roshan

    2015-01-01

    Full Text Available Subway system is one of the critical infrastructures in a society. In economic optimizations of risk control measures, valuing the loss of life and other financial losses in terms of money on the other hand, could influence the optimal investments in safety. The purpose is to contribute to the implementation of HSE in the transportation system. In this research, a fire risk assessment along with its economic loss estimation in the Direct Current (DC trains and rectifier substation (RS of Tehran subway is implemented. The number of fatalities, the extent of damage on the train equipment, etc., is then calculated in monetary unit. By using Event Tree Analysis (herein ETA, after identification of initiating events through observation, interviews, and evaluation of documents, event tree was constructed for each of them and the probability of multiple scenarios were computed. The scenario with the highest probability of fire in RS, including increased heats in the RTU panels generate a loss of at least 730 Million Rials. Accordingly, the minimum and maximum economic loss caused by fire on DC trains is minimum 510 and 1230 Million Rials, respectively. Conclusion: Given the findings of this study, the financial and human life risks, along with all tangible and intangible losses, which is considerable, the relevant managers must compare investments in safety, with the decrease of calculated economic risks as a result of fire accident in Tehran subway.

  12. Modeling and numerical analysis of granite rock specimen under mechanical loading and fire

    Directory of Open Access Journals (Sweden)

    Luc Leroy Ngueyep. Mambou

    2015-02-01

    Full Text Available The effect of ISO 834 fire on the mechanical properties of granite rock specimen submitted to uniaxial loading is numerically investigated. Based on Newton's second law, the rate-equation model of granite rock specimen under mechanical load and fire is established. The effect of heat treatment on the mechanical performance of granite is analyzed at the center and the ends of specimen. At the free end of granite rock specimen, it is shown that from 20 °C to 500 °C, the internal stress and internal strain are weak; whereas above 500 °C, they start to increase rapidly, announcing the imminent collapse. At the center of specimen, the analysis of the internal stress and internal strain reveals that the fire reduces the mechanical performance of granite significantly. Moreover, it is found that after 3 min of exposure to fire, the mechanical energy necessary to fragment the granite can be reduced up to 80%.

  13. [Impact of fire on carbon dynamics of Larix gmelinii forest in Daxing'an Mountains of North-East China: a simulation with CENTURY model].

    Science.gov (United States)

    Fang, Dong-Ming; Zhou, Guang-Sheng; Jiang, Yan-Ling; Jia, Bing-Rui; Xu, Zhen-Zhu; Sui, Xing-Hua

    2012-09-01

    Fire is one of the important natural disturbances to forest ecosystem, giving strong impact on the ecosystem carbon dynamics. By using CENTURY model, this paper simulated the responses of the carbon budget of Larix gmelinii forest in Huzhong area of Daxing' an Mountains to different intensities of fire. The results indicated that after the fires happened, the soil total carbon pool of the forest had a slight increase in the first few years and then recovered gradually, while the stand biomass carbon pool increased after an initial decrease, with the recovery rate of carbon pool of the stand fine components being faster than that of the coarse components. The fluctuation of the carbon pools increased with the increase of fire intensity. After the fires, both the net primary productivity (NPP) of forest vegetation and the soil heterotrophic respiration increased after an initial decrease, but the recovery rate of the NPP was faster than that of soil heterotrophic respiration, resulting in the alternation of the stand functioned as a carbon source or sink. After light fire, the forest still functioned as a weak carbon sink, and quickly recovered as a carbon sink to the level before the fire happened. After other intensities fire, the forest functioned as a carbon source within 9-12 years, and then turned back to a carbon sink again. It was suggested that lower intensity forest fire could promote the regeneration of L. gmelinii forest, reduce the combustibles, and have no strong impact on the stand carbon budget, while higher intensity forest fire would lead to the serious loss of soil- and tree carbon sequestration, retard the recovery of the forest, and thereby, the forest would be a carbon source in a longer term.

  14. A qualitative analysis of future air combat with 'fire and forget' missiles

    Science.gov (United States)

    Shinar, J.; Davidovitz, A.

    1987-01-01

    A set of previous examples have demonstrated that the two-target game formulation is adequate for modeling air-to-air combat between two aggressively motivated fighter aircraft. The present paper describes such an engagement between two aircraft of different speed but equipped with the same 'fire and forget' type guided missiles. The results of the analysis suggest a new concept of air combat tactics for future scenarios.

  15. Experimental analysis of a combustion reactor under co-firing coal with biomass

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Fabyo Luiz; Bazzo, Edson; Oliveira Junior, Amir Antonio Martins de [Universidade Federal de Santa Catarina, Florianopolis, SC (Brazil). LabCET], e-mail: ebazzo@emc.ufsc.br; Bzuneck, Marcelo [Tractebel Energia S.A., Complexo Termeletrico Jorge Lacerda, Capivari de Baixo, SC (Brazil)], e-mail: marcelob@tractebelenergia.com.br

    2010-07-01

    Mitigation of greenhouse gases emission is one of the most important issues in energy engineering. Biomass is a potential renewable source but with limited use in large scale energy production because of the relative smaller availability as compared to fossil fuels, mainly to coal. Besides, the costs concerning transportation must be well analysed to determine its economic viability. An alternative for the use of biomass as a primary source of energy is the co-firing, that is the possibility of using two or more types of fuels combined in the combustion process. Biomass can be co-fired with coal in a fraction between 10 to 25% in mass basis (or 4 to 10% in heat-input basis) without seriously impacting the heat release characteristics of most boilers. Another advantage of cofiring, besides the significant reductions in fossil CO{sub 2} emissions, is the reduced emissions of NO{sub x} and SO{sub x}. As a result, co-firing is becoming attractive for power companies worldwide. This paper presents results of some experimental analysis on co-firing coal with rice straw in a combustion reactor. The influence of biomass thermal share in ash composition is also discussed, showing that alkali and earth alkaline compounds play the most important role on the fouling and slagging behavior when co-firing. Some fusibility correlations that can assist in the elucidation of these behavior are presented and discussed, and then applied to the present study. Results show that for a biomass thermal share up to 20%, significant changes are not expected in fouling and slagging behavior of ash. (author)

  16. Global analysis of radiative forcing from fire-induced shortwave albedo change

    Directory of Open Access Journals (Sweden)

    G. López-Saldaña

    2014-05-01

    Full Text Available Land surface albedo, a key parameter to derive Earth's surface energy balance, is used in the parameterization of numerical weather prediction, climate monitoring and climate change impact assessments. Changes in albedo due to fire have not been fully investigated at continental and global scale. The main goal of this study therefore, is to quantify the changes in albedo produced by biomass burning activities and their associated shortwave radiative forcing. The study relies on the Moderate Resolution Imaging Spectroradiometer (MODIS MCD64A1 burned area product to create an annual composite of areas affected by fire and the MCD43C2 BRDF-Albedo snow-free product to compute a bihemispherical reflectance time series. The approximate day of burn is used to calculate the instantaneous change in shortwave Albedo. Using the corresponding National Centers for Environmental Prediction (NCEP monthly mean downward solar radiation flux at the surface, the global radiative forcing associated to fire was computed. The analysis reveals a mean decrease in shortwave albedo of −0.023 (1σ = 0.018 causing a mean positive radiative forcing of 6.31 W m–2 (1σ = 5.04 over the 2002–2012 time period in areas affected by fire. The greatest drop in mean shortwave albedo change occurs in 2002, which corresponds to the highest total area burnt (3.66 Mha observed in the same year and produces the highest mean radiative forcing (6.75 W m–2. Africa is the main contributor in terms of burned area but forests globally are giving the highest radiative forcing per unit area, thus give detectable changes in shortwave albedo. The global mean radiative forcing for the whole studied period ~ 0.04 W m–2 shows that the contribution of fires into the Earth system is not insignificant.

  17. Detection, emission estimation and risk prediction of forest fires in China using satellite sensors and simulation models in the past three decades--an overview.

    Science.gov (United States)

    Zhang, Jia-Hua; Yao, Feng-Mei; Liu, Cheng; Yang, Li-Min; Boken, Vijendra K

    2011-08-01

    Forest fires have major impact on ecosystems and greatly impact the amount of greenhouse gases and aerosols in the atmosphere. This paper presents an overview in the forest fire detection, emission estimation, and fire risk prediction in China using satellite imagery, climate data, and various simulation models over the past three decades. Since the 1980s, remotely-sensed data acquired by many satellites, such as NOAA/AVHRR, FY-series, MODIS, CBERS, and ENVISAT, have been widely utilized for detecting forest fire hot spots and burned areas in China. Some developed algorithms have been utilized for detecting the forest fire hot spots at a sub-pixel level. With respect to modeling the forest burning emission, a remote sensing data-driven Net Primary productivity (NPP) estimation model was developed for estimating forest biomass and fuel. In order to improve the forest fire risk modeling in China, real-time meteorological data, such as surface temperature, relative humidity, wind speed and direction, have been used as the model input for improving prediction of forest fire occurrence and its behavior. Shortwave infrared (SWIR) and near infrared (NIR) channels of satellite sensors have been employed for detecting live fuel moisture content (FMC), and the Normalized Difference Water Index (NDWI) was used for evaluating the forest vegetation condition and its moisture status.

  18. The motion analysis of fire video images based on moment features and flicker frequency

    Institute of Scientific and Technical Information of China (English)

    LI Jin; FONG N. K.; CHOW W. K.; WONG L.T.; LU Puyi; XU Dian-guo

    2004-01-01

    In this paper, motion analysis methods based on the moment features and flicker frequency features for early fire flame from ordinary CCD video camera were proposed, and in order to describe the changing of flame and disturbance of non-flame phenomena further more, the average changing pixel number of the first-order moments of consecutive flames has been defined in the moment analysis as well. The first-order moments of all kinds of flames used in our experiments present irregularly flickering, and their average changing pixel numbers of first-order moments are greater than fire-like disturbances. For the analysis of flicker frequency of flame, which is extracted and calculated in spatial domain, and therefore it is computational simple and fast. The method of extracting flicker frequency from video images is not affected by the catalogues of combustion material and distance. In experiments, we adopted two kinds of flames, i. e. , fixed flame and movable flame. Many comparing and disturbing experiments were done and verified that the methods can be used as criteria for early fire detection.

  19. A Cost Benefit Analysis of Fire Scout Vertical Takeoff and Landing Tactical Unmanned Aerial Vehicle (VTUAV) Operator Alternatives

    Science.gov (United States)

    2012-03-01

    48 Daniel Jurta et al. MQ-8B Fire Scout UAV Manning Cost Benefit Analysis. EMBA Project Report...December 8, 2012). 36 The exact cost of this training is difficult to ascertain, but a Naval Postgraduate School Executive MBA ( EMBA ) Capstone...57 Daniel Jurta et al. MQ-8B Fire Scout UAV Manning Cost Benefit Analysis. EMBA Project Report, Naval Postgraduate School, Monterey: Naval

  20. Identifying past fire regimes throughout the Holocene in Ireland using new and established methods of charcoal analysis

    Science.gov (United States)

    Hawthorne, Donna; Mitchell, Fraser J. G.

    2016-04-01

    Globally, in recent years there has been an increase in the scale, intensity and level of destruction caused by wildfires. This can be seen in Ireland where significant changes in vegetation, land use, agriculture and policy, have promoted an increase in fires in the Irish landscape. This study looks at wildfire throughout the Holocene and draws on lacustrine charcoal records from seven study sites spread across Ireland, to reconstruct the past fire regimes recorded at each site. This work utilises new and accepted methods of fire history reconstruction to provide a recommended analytical procedure for statistical charcoal analysis. Digital charcoal counting was used and fire regime reconstructions carried out via the CharAnalysis programme. To verify this record new techniques are employed; an Ensemble-Member strategy to remove the objectivity associated with parameter selection, a Signal to Noise Index to determine if the charcoal record is appropriate for peak detection, and a charcoal peak screening procedure to validate the identified fire events based on bootstrapped samples. This analysis represents the first study of its kind in Ireland, examining the past record of fire on a multi-site and paleoecological timescale, and will provide a baseline level of data which can be built on in the future when the frequency and intensity of fire is predicted to increase.

  1. Anti-aircraft Gun Fire Control Algorithm and Simulation Based on Ballistic%基于外弹道的高炮火控算法与仿真

    Institute of Scientific and Technical Information of China (English)

    李强; 欧阳攀

    2014-01-01

    In order to adapt to the improved target speed and maneuverability in modern warfare, and enhance the capability of anti-aircraft gun to attack air moving target,it has to give full play to the trajectory based on fire control computation precision advantages and accelerate the calculating speed. Through the integration of the external ballistic real-time calculating with calculate iterative algorithm and initial choice,a completely based on the ballistic calculating rapid fire control decoding algorithm system is received. The simulation results verified the external trajectory real-time calculating accuracy when compared with the firing table data. The solving hit problem of uniform linear motion and acceleration linear motion is analyzed with the usage of GDI + graphics functions and C# language. Analysis results show that the algorithm is feasible and provides a reference for fire-control system.%为适应现代战争中目标速度与机动性的提高,增强高炮打击空中运动目标能力,需要充分发挥基于外弹道火控解算精度高的优点,并提高解算速度。通过整合外弹道实时解算和解命中迭代算法与初值选择,得到了一种完全基于外弹道解算的快速火控解算算法体系。经过仿真计算,并将仿真结果与射表数据对比,验证了外弹道实时解算的准确性。利用GDI+图形功能基于C#语言仿真分析了匀速与匀加速直线运动目标的解命中问题,验证了算法的可行性,为火控系统的研制提供了参考。

  2. Three-dimensional computer simulation for combustion and NO{sub x} emission in a grate fired boiler at Baeckhamars, Sweden. Technical report[(Baeckhammars Bruk)

    Energy Technology Data Exchange (ETDEWEB)

    Dong Wei [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Metallurgy

    2000-05-01

    This report describes the fundament of mathematical modeling for the grate fired boilers in Part A, and presents the results from the numerical simulations for the flow pattern, combustion and NO{sub x} emission in the Baeckhammars grate fired boiler in Part B. The simulated boiler is equipped with a new secondary air supply system called Ecotube. The objective of this project is to develop and experimentally verify tools for computer simulations of solid biomass fuel combustion processes in a grate fired boiler. The work focuses on the numerical simulation using CFD technique and development of a NO{sub x} post processor. The unstructured mesh technique also has been used to discretize the boiler. An unstructured grid with total 284399 tetrahedral cells describes the three dimensional geometry and is used for flow field and combustion simulations. In order to simulate the combustion process in the boiler, a simplified grate bed model -- black-box bed model is used, which is based on the balance analysis of mass and energy on the grate bed and needless to consider any detailed and very difficult dynamic processes which have not been valuable by mathematical modeling on the grate bed yet. Therefore, it is quite convenient for industrial applications. In this work, both the cyanide route and the ammonia route for modeling the fuel containing nitrogen NO{sub x} are developed, and the former has been used to predict the NO generation in Baeckhammars bark boiler. Two 3D cases corresponding to 15 MW and 11 MW output thermal power respectively are simulated in detail. Results show that a new air supply system called Ecotube gives a considerably more uniform velocity, temperature and concentration distribution from the secondary air tubes to the upper part of the furnace. The upper furnace works almost as a 'plug flow reactor' which gives sufficient residence time for CO conversion and low NO{sub x} emission. The calculations of flow and mixing patterns in the

  3. NACOM code for analysis of postulated sodium spray fires in LMFBRs

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, S.S.

    1980-03-01

    An analysis of potential sodium spills and fires in liquid metal fast breeder reactors has been made to assess the maximum equipment cell loading conditions. A computer code called NACOM (sodium combustion) has been developed at Brookhaven National Laobratory (BNL) to analyze sodium spray fires. This report contains a detailed description of physical models used in this code as well as programming aspects. The single droplet combustion model and the model describing the droplets' motion are verified. Comparisons between NACOM predictions and SPRAY-3A predictions of the Atomics International (AI) LTV Jet Tests are made. Good agreement is found between the NACOM predictions and the experimental data. NACOM predictions of the pressure rise are more accurate than SPRAY-3A predictions for most of the cases studied. The code has been verified for oxygen concentrations ranging from 0 to 21%. NACOM utilizes more realistic single droplet and spray combustion models than SPRAY-3A. Moreover, NACOM does not utilize adjustable parameters for the burning rate equations, contrary to the approach taken with SPRAY-3A. Thus, the NACOM code is a more reliable code for use in the analysis of large-scale sodium spray fires in LMFBR containment cells. 24 refs., 32 figs.

  4. Trouble Shooting in Vertical Fire Hydrant Pump by Vibration Analysis - A Case Study

    Directory of Open Access Journals (Sweden)

    V. G . Arajpure

    2012-08-01

    Full Text Available The vertically mounted fire fighting pump used in pump house generally subjected to mechanical, structural and hydraulic problems. This generates dynamic load and produces vibrations of high frequencies and stresses which affects the pump performance and increases the maintenance cost. These problems leading to failure and damage of the costly components of pump houses. In this regard vibration analysis is necessary, to detect and diagnose faults of the fire fighting pumping house, to avoid any failure and efficient operation of pump system. This paper presents, the vibration analysis of different components of pump by actual measurement and performance testing at test rig. The vibrations are measured at no load as well as at full load condition. The defects in different components are identified and balanced. The balancing of the unbalanced motor fan enhances dynamic performance greatly due to decreased vibrations. The two different case studies of old as well as new pump are discussed here. The study becomes the benchmark for erection, commissioning and provides guidelines for fault diagnose of fire fighting pumps.

  5. Improving analytic hierarchy process applied to fire risk analysis of public building

    Institute of Scientific and Technical Information of China (English)

    SHI Long; ZHANG RuiFang; XIE QiYuan; FU LiHua

    2009-01-01

    The structure importance in Fault Tree Analysis (FTA) reflects how important Basic Events are to Top Event.Attribute at alternative level in Analytic Hierarchy Process (AHP) also reflect its importance to general goal.Based on the coherence of these two methods,an improved AHP is put forward.Using this improved method,how important the attribute is to the fire safety of public building can be ana-lyzed more credibly because of the reduction of subjective judgment.Olympic venues are very impor-tant public buildings in China.The fire safety evaluation of them will be a big issue to engineers.Im-proved AHP is a useful tool to the safety evaluation to these Olympic venues,and it will guide the evaluation in other areas.

  6. Simulation of fire and evacuation in a large building%某大型体育馆火灾安全疏散模拟

    Institute of Scientific and Technical Information of China (English)

    邢志祥; 戴闯; 宋华; 赵晓芳

    2011-01-01

    Fire simulation software FDS and evacuation software Building EXODUS were used to evaluate the fire safety desigof a gymnasium, and the available safety egress time and required safety egress time were calculated and compared.According to the simulation, and combining the existing " prescription" fire safety design, the performance-based fire safety design took account of extending the time before the dangers,shortening people reacting time, shortening the evacuating time.Based on the simulation and the exist fire facilities in the gym, suggestions were put forward in points of fire compart mentation, fire facilities, safety evacuating path, combined exits improvements.%使用火灾模拟软件FDS和人员疏散软件BuildingEXODUS对某体育馆消防设计进行评估,得出可用安全疏散时间与所需安全疏散时间并进行比较.根据模拟结果,结合现有的"处方式消防设计规范",从延长危险来临时间、缩短人员疏散反应时间、缩短疏散撤离时间三方面进行性能化防火设计.在综合模拟结果与该体育馆现有消防设施的基础上,从防火分区设置、消防系统、安全疏散通道设计、组合出口改进四方面提出修改建议.

  7. Response Predicting LTCC Firing Shrinkage: A Response Surface Analysis Study

    Energy Technology Data Exchange (ETDEWEB)

    Girardi, Michael; Barner, Gregg; Lopez, Cristie; Duncan, Brent; Zawicki, Larry

    2009-02-25

    The Low Temperature Cofired Ceramic (LTCC) technology is used in a variety of applications including military/space electronics, wireless communication, MEMS, medical and automotive electronics. The use of LTCC is growing due to the low cost of investment, short development time, good electrical and mechanical properties, high reliability, and flexibility in design integration (3 dimensional (3D) microstructures with cavities are possible)). The dimensional accuracy of the resulting x/y shrinkage of LTCC substrates is responsible for component assembly problems with the tolerance effect that increases in relation to the substrate size. Response Surface Analysis was used to predict product shrinkage based on specific process inputs (metal loading, layer count, lamination pressure, and tape thickness) with the ultimate goal to optimize manufacturing outputs (NC files, stencils, and screens) in achieving the final product design the first time. Three (3) regression models were developed for the DuPont 951 tape system with DuPont 5734 gold metallization based on green tape thickness.

  8. Advanced numerical modelling of a fire. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Heikkilae, L.; Keski-Rahkonen, O. [VTT Building Technology, Espoo (Finland)

    1996-03-01

    Experience and probabilistic risk assessments show that fires present a major hazard in a nuclear power plant (NPP). The PALOME project (1988-92) improved the quality of numerical simulation of fires to make it a useful tool for fire safety analysis. Some of the most advanced zone model fire simulation codes were acquired. The performance of the codes was studied through literature and personal interviews in earlier studies and BRI2 code from the Japanese Building Research Institute was selected for further use. In PALOME 2 project this work was continued. Information obtained from large-scale fire tests at the German HDR facility allowed reliable prediction of the rate of heat release and was used for code validation. BRI2 code was validated particularly by participation in the CEC standard problem `Prediction of effects caused by a cable fire experiment within the HDR-facility`. Participation in the development of a new field model code SOFIE specifically for fire applications as British-Swedish-Finnish cooperation was one of the goals of the project. SOFIE code was implemented at VTT and the first results of validation simulations were obtained. Well instrumented fire tests on electronic cabinets were carried out to determine source terms for simulation of room fires and to estimate fire spread to adjacent cabinets. The particular aim of this study was to measure the rate of heat release from a fire in an electronic cabinet. From the three tests, differing mainly in the amount of the fire load, data was obtained for source terms in numerical modelling of fires in rooms containing electronic cabinets. On the basis of these tests also a simple natural ventilation model was derived. (19 refs.).

  9. Statistical Analysis of Random Simulations : Bootstrap Tutorial

    NARCIS (Netherlands)

    Deflandre, D.; Kleijnen, J.P.C.

    2002-01-01

    The bootstrap is a simple but versatile technique for the statistical analysis of random simulations.This tutorial explains the basics of that technique, and applies it to the well-known M/M/1 queuing simulation.In that numerical example, different responses are studied.For some responses, bootstrap

  10. Holistic Nursing Simulation: A Concept Analysis.

    Science.gov (United States)

    Cohen, Bonni S; Boni, Rebecca

    2016-11-28

    Simulation as a technology and holistic nursing care as a philosophy are two components within nursing programs that have merged during the process of knowledge and skill acquisition in the care of the patients as whole beings. Simulation provides opportunities to apply knowledge and skill through the use of simulators, standardized patients, and virtual settings. Concerns with simulation have been raised regarding the integration of the nursing process and recognizing the totality of the human being. Though simulation is useful as a technology, the nursing profession places importance on patient care, drawing on knowledge, theories, and expertise to administer patient care. There is a need to promptly and comprehensively define the concept of holistic nursing simulation to provide consistency and a basis for quality application within nursing curricula. This concept analysis uses Walker and Avant's approach to define holistic nursing simulation by defining antecedents, consequences, and empirical referents. The concept of holism and the practice of holistic nursing incorporated into simulation require an analysis of the concept of holistic nursing simulation by developing a language and model to provide direction for educators in design and development of holistic nursing simulation.

  11. Manpower Analysis Using Discrete Simulation

    Science.gov (United States)

    2015-12-01

    Course STA-21 Seaman to Admiral (21st century) SQL Structured Query Language TOS Time on Station xiv THIS PAGE INTENTIONALLY LEFT BLANK...using Simkit—a widely available library based in the Java programming language for building Discrete Event Simulation (DES) models. By overriding...intervals (i.e., quarterly), while holding attrition negligible. For the purposes of modeling each new accession to the system, the Arrival

  12. Assessing Wildfire Risk in Cultural Heritage Properties Using High Spatial and Temporal Resolution Satellite Imagery and Spatially Explicit Fire Simulations: The Case of Holy Mount Athos, Greece

    Directory of Open Access Journals (Sweden)

    Giorgos Mallinis

    2016-02-01

    Full Text Available Fire management implications and the design of conservation strategies on fire prone landscapes within the UNESCO World Heritage Properties require the application of wildfire risk assessment at landscape level. The objective of this study was to analyze the spatial variation of wildfire risk on Holy Mount Athos in Greece. Mt. Athos includes 20 monasteries and other structures that are threatened by increasing frequency of wildfires. Site-specific fuel models were created by measuring in the field several fuel parameters in representative natural fuel complexes, while the spatial extent of the fuel types was determined using a synergy of high-resolution imagery and high temporal information from medium spatial resolution imagery classified through object-based analysis and a machine learning classifier. The Minimum Travel Time (MTT algorithm, as it is embedded in FlamMap software, was applied in order to evaluate Burn Probability (BP, Conditional Flame Length (CFL, Fire Size (FS, and Source-Sink Ratio (SSR. The results revealed low burn probabilities for the monasteries; however, nine out of the 20 monasteries have high fire potential in terms of fire intensity, which means that if an ignition occurs, an intense fire is expected. The outputs of this study may be used for decision-making for short-term predictions of wildfire risk at an operational level, contributing to fire suppression and management of UNESCO World Heritage Properties.

  13. Integrating software architectures for distributed simulations and simulation analysis communities.

    Energy Technology Data Exchange (ETDEWEB)

    Goldsby, Michael E.; Fellig, Daniel; Linebarger, John Michael; Moore, Patrick Curtis; Sa, Timothy J.; Hawley, Marilyn F.

    2005-10-01

    The one-year Software Architecture LDRD (No.79819) was a cross-site effort between Sandia California and Sandia New Mexico. The purpose of this research was to further develop and demonstrate integrating software architecture frameworks for distributed simulation and distributed collaboration in the homeland security domain. The integrated frameworks were initially developed through the Weapons of Mass Destruction Decision Analysis Center (WMD-DAC), sited at SNL/CA, and the National Infrastructure Simulation & Analysis Center (NISAC), sited at SNL/NM. The primary deliverable was a demonstration of both a federation of distributed simulations and a federation of distributed collaborative simulation analysis communities in the context of the same integrated scenario, which was the release of smallpox in San Diego, California. To our knowledge this was the first time such a combination of federations under a single scenario has ever been demonstrated. A secondary deliverable was the creation of the standalone GroupMeld{trademark} collaboration client, which uses the GroupMeld{trademark} synchronous collaboration framework. In addition, a small pilot experiment that used both integrating frameworks allowed a greater range of crisis management options to be performed and evaluated than would have been possible without the use of the frameworks.

  14. Thermal Analysis of Compressible CO2 Flow for PFE TeSS Nozzle of Fire Detection System

    Science.gov (United States)

    Zhang, Y. Michael; Lee, Wen-Chin; Keener, John F.; Smith, F. D.

    2002-01-01

    A thermal analysis of the compressible CO2 flow for the Portable Fire Extinguisher (PFE) system has been performed. A SINDA/FLUINT model has been developed for this analysis. The model includes the PFE tank and the TeSS nozzle, and both have initial temperature of 72 F. In order to investigate the thermal effect on the nozzle due to discharging CO2, the PFE TeSS nozzle pipe has been divided into three segments. This model also includes heat transfer predictions for PFE tank inner and outer wall surfaces. The simulation results show that the CO2 discharge rates have fulfilled the minimum flow requirements that the PFE system discharges 3.0 Ibm CO2 in 10 seconds and 5.5 Ibm of CO2 in 45 seconds during its operation. At 45 seconds, the PFE tank wall temperature is 63 F, and the TeSS nozzle cover wall temperatures for the three segments are 47 F, 53 F and 37 F, respectively. Thermal insulation for personal protection is used for the first two segments of the TeSS nozzle. The simulation results also indicate that at 50 seconds, the remaining CO2 in the tank may be near the triple point (gas, liquid and solid) state and, therefore, restricts the flow.

  15. Fire Perimeters

    Data.gov (United States)

    California Department of Resources — The Fire Perimeters data consists of CDF fires 300 acres and greater in size and USFS fires 10 acres and greater throughout California from 1950 to 2003. Some fires...

  16. Fire History

    Data.gov (United States)

    California Department of Resources — The Fire Perimeters data consists of CDF fires 300 acres and greater in size and USFS fires 10 acres and greater throughout California from 1950 to 2002. Some fires...

  17. Applying information network analysis to fire-prone landscapes: implications for community resilience

    Directory of Open Access Journals (Sweden)

    Derric B. Jacobs

    2017-03-01

    Full Text Available Resilient communities promote trust, have well-developed networks, and can adapt to change. For rural communities in fire-prone landscapes, current resilience strategies may prove insufficient in light of increasing wildfire risks due to climate change. It is argued that, given the complexity of climate change, adaptations are best addressed at local levels where specific social, cultural, political, and economic conditions are matched with local risks and opportunities. Despite the importance of social networks as key attributes of community resilience, research using social network analysis on coupled human and natural systems is scarce. Furthermore, the extent to which local communities in fire-prone areas understand climate change risks, accept the likelihood of potential changes, and have the capacity to develop collaborative mitigation strategies is underexamined, yet these factors are imperative to community resiliency. We apply a social network framework to examine information networks that affect perceptions of wildfire and climate change in Central Oregon. Data were collected using a mailed questionnaire. Analysis focused on the residents' information networks that are used to gain awareness of governmental activities and measures of community social capital. A two-mode network analysis was used to uncover information exchanges. Results suggest that the general public develops perceptions about climate change based on complex social and cultural systems rather than as patrons of scientific inquiry and understanding. It appears that perceptions about climate change itself may not be the limiting factor in these communities' adaptive capacity, but rather how they perceive local risks. We provide a novel methodological approach in understanding rural community adaptation and resilience in fire-prone landscapes and offer a framework for future studies.

  18. 火控雷达抗压制性干扰性能仿真及测试研究%Research on the anti-blanket jamming performance simulation and testing of the fire-control radar

    Institute of Scientific and Technical Information of China (English)

    张美星; 何强; 韩壮志

    2012-01-01

    Focusing on the testing of the anti-blanket jamming performance about the fire-control radar,this paper selected relative self-screening range as an indicator, then made some theoretical analysis andresearch from simulation, it also discussed on the testing standar adapted to the fire-control radar andmade a reasonable testing program, after all, an objective testing result was got.%针对火控雷达抗压制性干扰性能的测试,选取了相对自卫距离这一指标,对其进行了理论分析及仿真研究,讨论了适用于火控雷达的测试准则,并制定了合理的测试方案,最终得到了客观的测试结果.

  19. Analysis of forest fires causes and their motivations in northern Algeria: the Delphi method

    Directory of Open Access Journals (Sweden)

    Meddour-Sahar O

    2013-06-01

    Full Text Available Forest fires in Algeria are mostly human-caused and result from local social behavior, whether voluntary (arson or involuntary (negligence. Understanding the reasons why fires start is, therefore, a crucial factor in preventing or reducing their incidence, developing significant prevention efforts and designing specific fire prevention campaigns. The Delphi method is a promising tool for improving knowledge about how fire starts and why, and above all helps reduce the number of fires started by unknown causes, the majority type in Algeria. The Delphi method uses a set of procedures for eliciting and refining the opinions of a panel of experts on a particular subject of interest. This method was used in three case studies, in coastal or inner wilayas (provinces selected from a highly fire-prone area in north-central Algeria. Results showed the traditional use of fire in agriculture and forestry, in situations related to land use changes and in interpersonal conflicts are the major causes of voluntary fires. For involuntary events (negligence, experts unanimously identified the importance of the restart of fire, caused by fire crews who do not ensure the mopping up of controlled fires (91.49% and the negligent use of agricultural fires, particularly stubble burning (80.14%. For voluntary fires (arson, results highlight the importance of fires set for land use changes (77.30%, pyromania (67.38% and honey gathering (62.41%. Illegal dumping and burning of garbage was also mentioned by responders in all study-areas.

  20. Study on the external wall insulation system for fire prevention based on numerical simulation%基于数值模拟的外墙保温体系防火问题研究

    Institute of Scientific and Technical Information of China (English)

    赵平; 季经纬; 武爽

    2011-01-01

    针对国内现有的外墙外保温系统的防火性较差的现状,通过分析上海公寓楼外墙保温层的火灾,得到外墙外保温防火的三种重要因素(粘结或固定方式、防火隔离带的构造、防火保护面层).鉴于现在流行的保温材料为膨胀聚苯板(EPS),因而选用EPS作为模拟材料,利用数值模拟计算得出以下结论:认为火灾时有空腔的保温层比无空腔的保温层更危险;设置防火隔离带能有效得阻隔火灾的蔓延,较宽的隔离带效果更好.除此之外,外保温层防火设计中还应考虑以下三方面的问题,即遴选适当的保温材料、建议保温层也使用类似于防火分区的防火措施和保证保温效果的同时增加防火隔离带的宽度.研究结论和建议对于解决外墙保温体系防火问题具有重要的参考价值和现实意义.%Aiming at the status that the domestic existing exterior insulation system had poor fire resistance, through the analysis of apartment fire by exterior wall thermal insulation layer in Shanghai, three important factors exterior insulation fireproof were obtained induding binding or fixed mode, fire belt construction, fire protection layer. In view of the popular heat preservation material like EPS, it was selected to be the simulated material, and the following conclusions were obtained by numerical simulation: it was thought that in fire cavity insulation layer is more dangerous than no free cavity insulation; Setting fire belt can effectively block the spread of fire zone, and broader insulation belt has better effect. In addition, the design of insulation layer fire still should consider the following three problems, namely selecting proper insulation materials, suggesting insulation layer also use similar fire prevention measures liking fire compartment and increasing the midth of five bele at the same time of guaranteeing the thermal insulation. Research conclusions and recommendations for solving the

  1. Weapon Simulator Test Methodology Investigation: Comparison of Live Fire and Weapon Simulator Test Methodologies and the Effects of Clothing and Individual Equipment on Marksmanship

    Science.gov (United States)

    2016-09-15

    PROFICIENCY LIVE FIRE TESTING TEST METHODOLOGY FIRING TESTS(ORDNANCE) ACCURACY MEASUREMENT HUMAN FACTORS PERFORMANCE TESTS...SHOOTING PERFORMANCE BASE LINES REACTION TIME DATA COLLECTION CIE(CLOTHING AND INDIVIDUAL EQUIPMENT) U.S. Army Natick Soldier Research...Directorate (ARL-HRED) Dismounted Warrior Branch conducted the live fire trials at their M-range target shooting facility to provide quantitative measures

  2. Cold Galaxies on FIRE: Modeling the Most Luminous Starbursts in the Universe with Cosmological Zoom Simulations

    Science.gov (United States)

    Narayanan, Desika

    2014-10-01

    As the most luminous, heavily star-forming galaxies in the Universe, Submillimeter Galaxies at z 2-4 are key players in galaxy evolution. Since their discovery, SMGs have received significant attention from HST in characterizing their physical morphology, stellar masses, and star formation histories. Unfortunately, these physical constraints have been difficult for theorists to reconcile with galaxy formation simulations. Previous generations of simulations have all either {a} neglected baryons; {b} neglected radiative transfer {and connecting to observations}; or {c} neglected cosmological conditions. Here, we propose to conduct the first ever cosmological hydrodynamic simulations of Submillimeter Galaxy formation that couple with bona fide 3D dust radiative transfer calculations. These ultra-high resolution simulations {parsec-scale} will be the first to resolve the sites of dust obscuration, the cosmic growth history of SMGs, and their evolutionary destiny. Our proposal has two principle goals: {1} Develop the first ever model for SMG formation from cosmological simulations that include both baryons and dust radiative transfer; {2} Capitalize on our parsec-scale resolution to understand the connection between the physical properties of star-forming regions in high-z starbursts, and recent IMF constraints from present-epoch massive galaxies.

  3. Thermo-Mechanical Analysis of Water-Cooled Gun Barrel During Burst Firing

    Institute of Scientific and Technical Information of China (English)

    FAN Li-xia; HU Zhi-gang; ZHAO Jian-bo

    2006-01-01

    The thermo-mechanical stress and deformation of water-cooled gun barrel during burst firing are studied by finite element analysis (FEA). The problem is modeled in two steps: 1) A transient heat transfer analysis is first carried out in order to determine temperature evolution and to predict the residual temperatures during the burst firing event; 2) The thermo-mecha-nical stresses and deformation caused by both the residual temperature field and the gas pressure are then calculated. The results show that the residual temperature field tends to a steady state with the increasing of rounds. The residual temperature field has much effect on the gun barrel stress and deformation, especially on the assembly area between barrel and water jacket. The gage between the barrel and water jacket is the critical factor to the thermo-mechanical stress and deformation. The results of this analysis will be very useful to develop the new strength design theory of the liquid-cooled gun barrel.

  4. Fault tree analysis of fire and explosion accidents for dual fuel (diesel/natural gas) ship engine rooms

    Science.gov (United States)

    Guan, Yifeng; Zhao, Jie; Shi, Tengfei; Zhu, Peipei

    2016-09-01

    In recent years, China's increased interest in environmental protection has led to a promotion of energy-efficient dual fuel (diesel/natural gas) ships in Chinese inland rivers. A natural gas as ship fuel may pose dangers of fire and explosion if a gas leak occurs. If explosions or fires occur in the engine rooms of a ship, heavy damage and losses will be incurred. In this paper, a fault tree model is presented that considers both fires and explosions in a dual fuel ship; in this model, dual fuel engine rooms are the top events. All the basic events along with the minimum cut sets are obtained through the analysis. The primary factors that affect accidents involving fires and explosions are determined by calculating the degree of structure importance of the basic events. According to these results, corresponding measures are proposed to ensure and improve the safety and reliability of Chinese inland dual fuel ships.

  5. Fault Tree Analysis of Fire and Explosion Accidents for Dual Fuel (Diesel/Natural Gas) Ship Engine Rooms

    Institute of Scientific and Technical Information of China (English)

    Yifeng Guan; Jie Zhao; Tengfei Shiand Peipei Zhu

    2016-01-01

    In recent years, China’s increased interest in environmental protection has led to a promotion of energy-efficient dual fuel (diesel/natural gas) ships in Chinese inland rivers. A natural gas as ship fuel may pose dangers of fire and explosion if a gas leak occurs. If explosions or fires occur in the engine rooms of a ship, heavy damage and losses will be incurred. In this paper, a fault tree model is presented that considers both fires and explosions in a dual fuel ship;in this model, dual fuel engine rooms are the top events. All the basic events along with the minimum cut sets are obtained through the analysis.The primary factors that affect accidents involving fires and explosions are determined by calculating the degree of structure importance of the basic events.According to these results, corresponding measures are proposed to ensure and improve the safety and reliability of Chinese inland dual fuel ships.

  6. Simulation on an optimal combustion control strategy for 3-D temperature distributions in tangentially pc-fired utility boiler furnaces

    Institute of Scientific and Technical Information of China (English)

    WANG Xi-fen; ZHOU Huai-chun

    2005-01-01

    The control of 3-D temperature distribution in a utility boiler furnace is essential for the safe, economic and clean operation of pcfired furnace with multi-burner system. The development of the visualization of 3-D temperature distributions in pc-fired furnaces makes it possible for a new combustion control strategy directly with the fumacs temperature as its goal to improve the control quality for the combustion processes. Studied in this paper is such a new strategy that the whole furnace is divided into several parts in the vertical direction, and the average temperature and its bias from the center in every cross section can be extracted from the visualization results of the 3-D temperature distributions. In the simulation stage, a computational fluid dynamics (CFD) code served to calculate the 3-D temperature distributions in a furnace, then a linear model was set up to relate the features of the temperature distributions with the input of the combustion processes, such as the flow rates of fuel and air fed into the furnaces through all the burners. The adaptive genetic algorithm was adopted to find the optimal combination of the whole input parameters which ensure to form an optimal 3-D temperature field in the furnace desired for the operation of boiler. Simulation results showed that the strategy could soon find the factors making the temperature distribution apart from the optimal state and give correct adjusting suggestions.

  7. Analysis of pressure safety valves for fire protection on offshore oil and gas installations

    DEFF Research Database (Denmark)

    Bjerre, Michael Skov; Eriksen, Jacob; Andreasen, Anders;

    2016-01-01

    to see the effect of the installed PSV. It is found that when a fire affects the unwetted part of a vessel, the PSV offers only minor or no additional protection. When a fire affects the wetted part of a vessel, the PSV relieve the inventory as designed. It is argued that PSVs provide insufficient fire...... fire, large jet fire, and a pool fire on both the wetted and unwetted part of the vessels. Rupture times of the vessels are calculated by comparing the pressure in the vessel with the tensile strength of the material. Rupture times are then compared for the vessels, with and without a PSV, in order...

  8. Analysis of factors influencing fire damage to concrete using nonlinear resonance vibration method

    Energy Technology Data Exchange (ETDEWEB)

    Park, Gang Kyu; Park, Sun Jong; Kwak, Hyo Gyoung [Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, KAIST, Daejeon (Korea, Republic of); Yim, Hong Jae [Dept. of Construction and Disaster Prevention Engineering, Kyungpook National University, Sangju (Korea, Republic of)

    2015-04-15

    In this study, the effects of different mix proportions and fire scenarios (exposure temperatures and post-fire-curing periods) on fire-damaged concrete were analyzed using a nonlinear resonance vibration method based on nonlinear acoustics. The hysteretic nonlinearity parameter was obtained, which can sensitively reflect the damage level of fire-damaged concrete. In addition, a splitting tensile strength test was performed on each fire-damaged specimen to evaluate the residual property. Using the results, a prediction model for estimating the residual strength of fire-damaged concrete was proposed on the basis of the correlation between the hysteretic nonlinearity parameter and the ratio of splitting tensile strength.

  9. Passive-solar simulation analysis

    Energy Technology Data Exchange (ETDEWEB)

    1982-12-05

    A passive solar heating component (TANKWALL) was developed. TANKWALL is a fiberglass water wall, selective surfaced, solar absorption, thermal storage tank. Testing of the thermal performance of TANKWALL was performed which included a series of room and instrumentation calibration tests and several comparison experiments where TANKWALL was operated side-by-side with other passive solar configurations. Relevant effective heat transfer values (solar absorptance, capacitance, conductance) were derived using a thermal network computer model and data from the above experiments. Then using these heat transfer values, three hour-by-hour computer simulations were run for a proto-typical passive solar house using various solar systems and standard hourly weather data. The subject house had a Building Load Coefficient of 8899.2 Btu/H, a vertical south facing 200 sq. ft. collector, and a Load/Collector Ratio of 44.5. It was found that the TANKWALL with selective surface performs significantly better in the Dayton, Ohio area than either the painted 12 inch Trombe wall or the painted TANKWALL with R-4.5 night insulation.

  10. Cellular automata-based tunnel fire simulation%基于元胞自动机的井巷火灾仿真

    Institute of Scientific and Technical Information of China (English)

    李翠平; 胡磊; 侯定勇; 张佳

    2013-01-01

    提出了一种基于元胞自动机的井巷火灾可视化仿真方法。在矿井巷道可视化的基础上,通过对火灾元胞进行表征,综合考虑可燃物类型与投放密度、井巷通风、井巷坡度等因素对井巷火源引燃效果的影响及双扩散作用、井巷通风、浮力作用和节流作用等因素对火灾烟气蔓延效果的影响,采用概率函数进行元胞自动机建模,构建了表达元胞温度的井巷火源燃烧模型和表达元胞浓度的井巷火灾烟气蔓延模型。基于火源元胞燃烧演化规则和烟气元胞蔓延演化规则,通过可视化手段展示了井巷火灾火源燃烧和有害气体浓度的时空发展变化。同时以矿山实际数据进行检验,说明了基于元胞自动机的井巷火灾仿真的可行性与有效性。%This article introduces a mine fire visualization simulation method based on cellular automata. On the basis of mine tunnel visualization, a tunnel fire combustion model for expressing cellular temperature and a tunnel fire smoke spread model for expressing cellular concentration were built by fire cell characterization. In these models the influence of fuel type and input density, ventilation and roadway slope on mine fire ignition and the effect of double diffusion, ventilation, buoyancy and throttling on fire smoke spread were taken into account, and a probability function was used for cellular automata modelling. Then according to the fire cellular combustion evolution rules and smoke cellular spreading evolution rules, the spatial changes of tunnel fire burning and harmful gas concentration were demonstrated through visualization means. Actual data from a mine proves the feasibility and effectiveness of tunnel fire simulation based on cellular automata.

  11. Smoke simulation for fire engineering using a multigrid method on graphics hardware

    DEFF Research Database (Denmark)

    Glimberg, Stefan; Erleben, Kenny; Bennetsen, Jens

    2009-01-01

    interactive physical simulation for engineering purposes, has the benefit of reducing production turn-around time. We have measured speed-up improvements by a factor of up to 350, compared to existing CPU-based solvers. The present CUDA-based solver promises huge potential in economical benefits, as well...

  12. Analysis of the annual trends of fire density in Southern Europe

    Science.gov (United States)

    Oliveira, Sandra; Oehler, Friderike; San-Miguel Ayanz, Jesus; Camia, Andrea; Durrant, Tracy

    2010-05-01

    Wildland fires are a major hazard in Europe, particularly in the Mediterranean area. The assessment of fire risk constitutes an important tool for forest fire management. Long-term or structural fire risk, even though it is a key component for the support of fire prevention activities, has not been investigated systematically at the European level. A research initiative is currently ongoing at the Joint Research Centre with the aim to develop a long-term fire risk model for Europe, to be integrated in the European Forest Fire Information System (EFFIS). For this purpose, fire risk is considered as a combination of fire occurrence and fire outcome. Fire occurrence is assessed based on the probability of ignition and estimated fire behaviour, while fire outcome is based on vulnerability. This study analysed the spatial and temporal trends of fire occurrence (ignition) in the Euro-Mediterranean region, from 1985 until 2007, in order to understand the subjacent factors of the fire distribution patterns, a topic even more relevant in a context of climatic and environmental change. Fire ignition data was obtained from the European Forest Fire Database of EFFIS, which currently includes data gathered from 21 countries and about 1.87 million individual fire records, of which 1.22 million are from the Euro-Mediterranean region. Due to the geo-location uncertainty associated with the database, fire density (number of fires/km2) was used as a surrogate of fire ignition. The total number of fire events per year was spatially distributed within the wildland area of the correspondent NUTS3 region (administrative districts used as geographical units to report fire events in the database). Corine Land Cover (CLC) 1990 was used to define the wildland areas for the period between 1985 and 1994 and CLC 2000 for the period between 1995 and 2007. Kernel density estimation methods (e.g. Amatulli et al., 2007) were applied to obtain the dependent variable in a continuous format

  13. Computer aided seismic and fire retrofitting analysis of existing high rise reinforced concrete buildings

    CERN Document Server

    Hussain, Raja Rizwan; Hasan, Saeed

    2016-01-01

    This book details the analysis and design of high rise buildings for gravity and seismic analysis. It provides the knowledge structural engineers need to retrofit existing structures in order to meet safety requirements and better prevent potential damage from such disasters as earthquakes and fires. Coverage includes actual case studies of existing buildings, reviews of current knowledge for damages and their mitigation, protective design technologies, and analytical and computational techniques. This monograph also provides an experimental investigation on the properties of fiber reinforced concrete that consists of natural fibres like coconut coir and also steel fibres that are used for comparison in both Normal Strength Concrete (NSC) and High Strength Concrete (HSC). In addition, the authors examine the use of various repair techniques for damaged high rise buildings. The book will help upcoming structural design engineers learn the computer aided analysis and design of real existing high rise buildings ...

  14. Analysis of the behaviour of biofuel-fired gas turbine power plants

    Directory of Open Access Journals (Sweden)

    Escudero Marcos

    2012-01-01

    Full Text Available The utilisation of biofuels in gas turbines is a promising alternative to fossil fuels for power generation. It would lead to a significant reduction of CO2 emissions using an existing combustion technology, although considerable changes appear to be required and further technological development is necessary. The goal of this work is to conduct energy and exergy analyses of the behaviour of gas turbines fired with biogas, ethanol and synthesis gas (bio-syngas, compared with natural gas. The global energy transformation process (i.e., from biomass to electricity also has been studied. Furthermore, the potential reduction of CO2 emissions attained by the use of biofuels has been determined, after considering the restrictions regarding biomass availability. Two different simulation tools have been used to accomplish this work. The results suggest a high interest in, and the technical viability of, the use of Biomass Integrated Gasification Combined Cycle (BioIGCC systems for large scale power generation.

  15. All fired up

    CERN Multimedia

    CERN Bulletin

    2013-01-01

    Members of the Directorate and their support staff took part in a fire-fighting course organised by the CERN Fire Brigade just before the end-of-year break.  The Bulletin takes a look at the fire-fighting training on offer at CERN.   At CERN the risk of fire can never be under-estimated. In order to train personnel in the use of fire extinguishers, CERN's fire training centre in Prévessin acquired a fire-simulation platform in 2012. On the morning of 17 December 2012, ten members of the CERN directorate and their support staff tried out the platform, following in the footsteps of 400 other members of the CERN community who had already attended the course. The participants were welcomed to the training centre by Gilles Colin, a fire-fighter and instructor, who gave them a 30-minute introduction to general safety and the different types of fire and fire extinguishers, followed by an hour of practical instruction in the simulation facility. There they were able to pract...

  16. Fuel type characterization and potential fire behavior estimation in Sardinia and Corsica islands

    Science.gov (United States)

    Bacciu, V.; Pellizzaro, G.; Santoni, P.; Arca, B.; Ventura, A.; Salis, M.; Barboni, T.; Leroy, V.; Cancellieri, D.; Leoni, E.; Ferrat, L.; Perez, Y.; Duce, P.; Spano, D.

    2012-04-01

    BEHAVE fire behavior prediction system (Andrews, 1989) and experimental fuel data. Fire behavior was simulated by setting different weather scenarios representing the most frequent summer meteorological conditions. The simulation outputs (fireline intensity, rate of spread, flame length) were then analyzed for clustering the different fuel types in relation to their potential fire behavior. The results of this analysis can be used to produce fire behavior fuel maps that are important tools in evaluating fire hazard and risk for land management planning, locating and rating fuel treatments, and aiding in environmental assessments and fire danger programs modeling. This work is supported by FUME Project FP7-ENV-2009-1, Grant Agreement Number 243888 and Proterina-C Project, EU Italia-Francia Marittimo 2007-2013 Programme.

  17. Stochastic simulation algorithms and analysis

    CERN Document Server

    Asmussen, Soren

    2007-01-01

    Sampling-based computational methods have become a fundamental part of the numerical toolset of practitioners and researchers across an enormous number of different applied domains and academic disciplines. This book provides a broad treatment of such sampling-based methods, as well as accompanying mathematical analysis of the convergence properties of the methods discussed. The reach of the ideas is illustrated by discussing a wide range of applications and the models that have found wide usage. The first half of the book focuses on general methods, whereas the second half discusses model-specific algorithms. Given the wide range of examples, exercises and applications students, practitioners and researchers in probability, statistics, operations research, economics, finance, engineering as well as biology and chemistry and physics will find the book of value.

  18. Fire behavior potential in central Saskatchewan under predicted climate change : summary document

    Energy Technology Data Exchange (ETDEWEB)

    Parisien, M.; Hirsch, K.; Todd, B.; Flannigan, M. [Canadian Forest Service, Edmonton, AB (Canada); Kafka, V. [Parks Canada, Ottawa, ON (Canada); Flynn, N. [Alberta Univ., Edmonton, AB (Canada)

    2005-07-01

    This study assesses fire danger and fire behaviour potential in central Saskatchewan using simulated climate scenarios produced by the Canadian Regional Climate Model (CRCM), including scenario analysis of base, double and triple level carbon dioxide in the atmosphere and uses available forest fuels to develop an absolute measure of fire behaviour. For each of these climate scenarios, the CRCM-generated weather was used as input variables into the Canadian Forest Fire Behavior Prediction (FBP) System. Fire behavior potential was quantified using head fire intensity, a measure of the fire's energy output because it can be related to fire behavior characteristics, suppression effectiveness, and fire effects. The report discusses the implications of fire behavior potential changes for fire and forest management. Preliminary results suggest a large increase in area burned in the study area by the end of the twenty-first century. Some of the possible fire management activities for long-term prediction include: pre-positioning of resources, preparedness planning, prioritization of fire and forest management activities and fire threat evaluation. 16 refs., 1 tab, 7 figs.

  19. Analysis of arson fire debris by low temperature dynamic headspace adsorption porous layer open tubular columns.

    Science.gov (United States)

    Nichols, Jessica E; Harries, Megan E; Lovestead, Tara M; Bruno, Thomas J

    2014-03-21

    In this paper we present results of the application of PLOT-cryoadsorption (PLOT-cryo) to the analysis of ignitable liquids in fire debris. We tested ignitable liquids, broadly divided into fuels and solvents (although the majority of the results presented here were obtained with gasoline and diesel fuel) on three substrates: Douglas fir, oak plywood and Nylon carpet. We determined that PLOT-cryo allows the analyst to distinguish all of the ignitable liquids tested by use of a very rapid sampling protocol, and performs better (more recovered components, higher efficiency, lower elution solvent volumes) than a conventional purge and trap method. We also tested the effect of latency (the time period between applying the ignitable liquid and ignition), and we tested a variety of sampling times and a variety of PLOT capillary lengths. Reliable results can be obtained with sampling time periods as short as 3min, and on PLOT capillaries as short as 20cm. The variability of separate samples was also assessed, a study made possible by the high throughput nature of the PLOT-cryo method. We also determined that the method performs better than the conventional carbon strip method that is commonly used in fire debris analysis.

  20. Recovering lead from cupel waste generated in gold analysis by Pb-Fire assay.

    Science.gov (United States)

    Cerceau, Cristiane Isaac; Carvalho, Cornélio de Freitas; Rabelo, Ana Carolina Silveira; Dos Santos, Cláudio Gouvea; Gonçalves, Sabrina Mayra Dias; Varejão, Eduardo Vinícius Vieira

    2016-12-01

    Because of its precision and accuracy, Pb-Fire assay is the most employed method for gold analysis in geological materials. At the second stage of the method, namely cupellation, lead is oxidized to PbO which is absorbed by the cupel, leading to metallic gold as a tiny bend at the bottom of the recipient. After cupellation, cupel becomes highly contaminated with lead, making its disposal a serious risk of environmental contamination. In the present work, a leaching process for removing lead from cupel waste is proposed, which allowed for removing 96% of PbO by weight. After a precipitation step, 92.0% of lead was recovered from leachates in the form of PbSO4. Lead in the solid wastes left by the extraction was above the limit established by Brazilian legislation and these were classified as non-hazardous. Finally, secondary effluents generated after the precipitation step presented lead content more than twenty times lower than that of leachates from cupel waste. Tons of cupel waste are annually generated from gold analysis by Pb-Fire assay. Thus, the proposed method can contribute to prevent the discharge of high amounts of lead into the environment. Also, recovery of lead can help to partially meet the industrial demand for lead compounds.

  1. GEOMETRIC AND MATERIAL NONLINEAR ANALYSIS OF REINFORCED CONCRETE SLABS AT FIRE ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Ayad A. Abdul -Razzak

    2013-05-01

    Full Text Available In the present study a nonlinear finite element analysis is presented  to predict the fire resistance of reinforced concrete slabs at fire environment. An eight node layered degenerated shell element utilizing Mindlin/Reissner thick plate theory is employed. The proposed model considered cracking, crushing and yielding of concrete and steel at elevated temperatures. The layered approach is used to represent the steel reinforcement and discretize the concrete slab through the thickness. The reinforcement steel is represented as a smeared layer of equivalent thickness with uniaxial strength and rigidity properties.Geometric nonlinear analysis may play an important role in the behavior of reinforced concrete slabs at high temperature. Geometrical nonlinearity in the layered approach is considered in the mathematical model, which is based on the total Lagrangian approach taking into account Von Karman assumptions.Finally two examples for which experimental results are available are analyzed, using the proposed model .The comparison showed good agreement with experimental results. 

  2. Analysis of Original Causes of Reed Fires in Zhalong Nature Wetland Reserve in Heilongjiang Province

    Institute of Scientific and Technical Information of China (English)

    WANG Mingyu; SHU Lifu; TIAN Xiaorui; WANG Zhicheng

    2006-01-01

    In recent years, serious reed fires occurred in Zhalong Nature Reserve in Heilongjiang Province in China. From 19th to 28th of March 2005, 12 fires occurred in Zhalong Nature Reserve, and the fires spread to Qiqihaer City, Duerberte Mongolian Autonomous County, Lindian County and Daqing City. The burned area was about 18 666 ha. Meteorological factor was the leading factor of its fire environment in Zhalong Nature Reserve, which came into being for a long time. Long-term drought and shortage of rain made the reed and meadow withered and yellow and thus greatly reduced the water content of withered fallen leaves and humus. Much fuel was accumulated and became dry, thus forming the fire environment. Fires in Zhalong Nature Reserve were mainly strong surface fires accompanied by the spread of underground fire. It was extremely easy for reed to burn and spread very quickly. Once a fire broke out, it could spread rapidly to a scene of large fire area, and sometimes it could burn for a long time. Due to lack of correct understanding of the wetland fire and inconvenient wetland traffic, it was unable to find and put out wetland fire in time to save life and property early.

  3. Numerical study of co-firing pulverized coal and biomass inside a cement calciner.

    Science.gov (United States)

    Mikulčić, Hrvoje; von Berg, Eberhard; Vujanović, Milan; Duić, Neven

    2014-07-01

    The use of waste wood biomass as fuel is increasingly gaining significance in the cement industry. The combustion of biomass and particularly co-firing of biomass and coal in existing pulverized-fuel burners still faces significant challenges. One possibility for the ex ante control and investigation of the co-firing process are computational fluid dynamics (CFD) simulations. The purpose of this paper is to present a numerical analysis of co-firing pulverized coal and biomass in a cement calciner. Numerical models of pulverized coal and biomass combustion were developed and implemented into a commercial CFD code FIRE, which was then used for the analysis. Three-dimensional geometry of a real industrial cement calciner was used for the analysis. Three different co-firing cases were analysed. The results obtained from this study can be used for assessing different co-firing cases, and for improving the understanding of the co-firing process inside the calculated calciner.

  4. Simulating an infection growth model in certain healthy metabolic pathways of Homo sapiens for highlighting their role in Type I Diabetes mellitus using fire-spread strategy, feedbacks and sensitivities.

    Science.gov (United States)

    Tagore, Somnath; De, Rajat K

    2013-01-01

    Disease Systems Biology is an area of life sciences, which is not very well understood to date. Analyzing infections and their spread in healthy metabolite networks can be one of the focussed areas in this regard. We have proposed a theory based on the classical forest fire model for analyzing the path of infection spread in healthy metabolic pathways. The theory suggests that when fire erupts in a forest, it spreads, and the surrounding trees also catch fire. Similarly, when we consider a metabolic network, the infection caused in the metabolites of the network spreads like a fire. We have constructed a simulation model which is used to study the infection caused in the metabolic networks from the start of infection, to spread and ultimately combating it. For implementation, we have used two approaches, first, based on quantitative strategies using ordinary differential equations and second, using graph-theory based properties. Furthermore, we are using certain probabilistic scores to complete this task and for interpreting the harm caused in the network, given by a 'critical value' to check whether the infection can be cured or not. We have tested our simulation model on metabolic pathways involved in Type I Diabetes mellitus in Homo sapiens. For validating our results biologically, we have used sensitivity analysis, both local and global, as well as for identifying the role of feedbacks in spreading infection in metabolic pathways. Moreover, information in literature has also been used to validate the results. The metabolic network datasets have been collected from the Kyoto Encyclopedia of Genes and Genomes (KEGG).

  5. Simulating an infection growth model in certain healthy metabolic pathways of Homo sapiens for highlighting their role in Type I Diabetes mellitus using fire-spread strategy, feedbacks and sensitivities.

    Directory of Open Access Journals (Sweden)

    Somnath Tagore

    Full Text Available Disease Systems Biology is an area of life sciences, which is not very well understood to date. Analyzing infections and their spread in healthy metabolite networks can be one of the focussed areas in this regard. We have proposed a theory based on the classical forest fire model for analyzing the path of infection spread in healthy metabolic pathways. The theory suggests that when fire erupts in a forest, it spreads, and the surrounding trees also catch fire. Similarly, when we consider a metabolic network, the infection caused in the metabolites of the network spreads like a fire. We have constructed a simulation model which is used to study the infection caused in the metabolic networks from the start of infection, to spread and ultimately combating it. For implementation, we have used two approaches, first, based on quantitative strategies using ordinary differential equations and second, using graph-theory based properties. Furthermore, we are using certain probabilistic scores to complete this task and for interpreting the harm caused in the network, given by a 'critical value' to check whether the infection can be cured or not. We have tested our simulation model on metabolic pathways involved in Type I Diabetes mellitus in Homo sapiens. For validating our results biologically, we have used sensitivity analysis, both local and global, as well as for identifying the role of feedbacks in spreading infection in metabolic pathways. Moreover, information in literature has also been used to validate the results. The metabolic network datasets have been collected from the Kyoto Encyclopedia of Genes and Genomes (KEGG.

  6. How wild is your model fire? Constraining WRF-Chem wildfire smoke simulations with satellite observations

    Science.gov (United States)

    Fischer, E. V.; Ford, B.; Lassman, W.; Pierce, J. R.; Pfister, G.; Volckens, J.; Magzamen, S.; Gan, R.

    2015-12-01

    Exposure to high concentrations of particulate matter (PM) present during acute pollution events is associated with adverse health effects. While many anthropogenic pollution sources are regulated in the United States, emissions from wildfires are difficult to characterize and control. With wildfire frequency and intensity in the western U.S. projected to increase, it is important to more precisely determine the effect that wildfire emissions have on human health, and whether improved forecasts of these air pollution events can mitigate the health risks associated with wildfires. One of the challenges associated with determining health risks associated with wildfire emissions is that the low spatial resolution of surface monitors means that surface measurements may not be representative of a population's exposure, due to steep concentration gradients. To obtain better estimates of ambient exposure levels for health studies, a chemical transport model (CTM) can be used to simulate the evolution of a wildfire plume as it travels over populated regions downwind. Improving the performance of a CTM would allow the development of a new forecasting framework that could better help decision makers estimate and potentially mitigate future health impacts. We use the Weather Research and Forecasting model with online chemistry (WRF-Chem) to simulate wildfire plume evolution. By varying the model resolution, meteorology reanalysis initial conditions, and biomass burning inventories, we are able to explore the sensitivity of model simulations to these various parameters. Satellite observations are used first to evaluate model skill, and then to constrain the model results. These data are then used to estimate population-level exposure, with the aim of better characterizing the effects that wildfire emissions have on human health.

  7. Finite Element Analysis of Fire Truck Chassis for Steel and Carbon Fiber Materials

    Directory of Open Access Journals (Sweden)

    Salvi Gauri Sanjay

    2014-07-01

    Full Text Available Chassis is the foremost component of an automobile that acts as the frame to support the vehicle body. Hence the frame ought to be very rigid and robust enough to resist shocks vibrations and stresses acting on a moving vehicle. Steel in its numerous forms is commonly used material for producing chassis and overtime alumimium has acquired its use. However, in this study traditional materials are replaced with ultra light weight carbon fiber materials. High strength and low weight of carbon fibers makes it ideal for manufacturing automotive chassis. This paper depicts the modal and static structural analysis of TATA 407 fire truck chassis frame for steel as well as carbon fibers. From the analyzed results, stress, strain and total deformation values were compared for both the materials. Since it is easy to analyze structural systems by finite element method, the chassis is modified using PRO-E and the Finite Element Analysis is performed on ANSYS workbench.

  8. Laboratory Investigations of Ni-Al Coatings Exposed to Conditions Simulating Biomass Firing

    DEFF Research Database (Denmark)

    Wu, Duoli; Okoro, Sunday Chukwudi; Dahl, Kristian Vinter

    2016-01-01

    Fireside corrosion is a key problem when using biomass fuels in power plants. A possible solution is to apply corrosion resistant coatings. The present paper studies the corrosion and interdiffusion behaviour of a Ni-Al diffusion coating on austenitic stainless steel (TP347H). Ni-Al coatings were...... prepared by electrolytic deposition of nickel followed by pack aluminizing performed at 650˚C. A uniform and dense Ni-Al coating with an outer layer of Ni2Al3 and an inner Ni layer was formed. Samples were exposed to 560°C for 168h in an atmosphere simulating biomass combustion. This resulted in localized...

  9. Development of an Optimizing Control Concept for Fossil-Fired Boilers using a Simulation Model

    DEFF Research Database (Denmark)

    Mortensen, J. H.; Mølbak, T.; Commisso, M.B.

    1997-01-01

    of implementation and commissioning. The optimizing control system takes into account the multivariable and nonlinear characteristics of the boiler process as a gain-scheduled LQG-controller is utilized. For the purpose of facilitating the control concept development a dynamic simulation model of the boiler process......An optimizing control system for improving the load following capabilities of power plant units has been developed. The system is implemented as a complement producing additive control signals to the existing boiler control system, a concept which has various practical advantages in terms...... model when designing a new control concept are discussed....

  10. Economic analysis of atmospheric mercury emission control for coal-fired power plants in China.

    Science.gov (United States)

    Ancora, Maria Pia; Zhang, Lei; Wang, Shuxiao; Schreifels, Jeremy; Hao, Jiming

    2015-07-01

    Coal combustion and mercury pollution are closely linked, and this relationship is particularly relevant in China, the world's largest coal consumer. This paper begins with a summary of recent China-specific studies on mercury removal by air pollution control technologies and then provides an economic analysis of mercury abatement from these emission control technologies at coal-fired power plants in China. This includes a cost-effectiveness analysis at the enterprise and sector level in China using 2010 as a baseline and projecting out to 2020 and 2030. Of the control technologies evaluated, the most cost-effective is a fabric filter installed upstream of the wet flue gas desulfurization system (FF+WFGD). Halogen injection (HI) is also a cost-effective mercury-specific control strategy, although it has not yet reached commercial maturity. The sector-level analysis shows that 193 tons of mercury was removed in 2010 in China's coal-fired power sector, with annualized mercury emission control costs of 2.7 billion Chinese Yuan. Under a projected 2030 Emission Control (EC) scenario with stringent mercury limits compared to Business As Usual (BAU) scenario, the increase of selective catalytic reduction systems (SCR) and the use of HI could contribute to 39 tons of mercury removal at a cost of 3.8 billion CNY. The economic analysis presented in this paper offers insights on air pollution control technologies and practices for enhancing atmospheric mercury control that can aid decision-making in policy design and private-sector investments.

  11. Determination of firing distance. Lead analysis on the target by atomic absorption spectroscopy (AAS).

    Science.gov (United States)

    Gagliano-Candela, Roberto; Colucci, Anna P; Napoli, Salvatore

    2008-03-01

    This paper reports a method for the determination of the firing distance. Atomic absorption spectroscopy (AAS) was used to determine the lead (Pb) pattern around bullet holes produced by shots on test targets from the gun. Test shots were made with a Colt 38 Special at 5, 10, 20, 25, 30, 35, 40, 45, 50, 60, 80, and 100 cm target distance. The target was created with sheets of Whatman no. 1 paper on a polystyrene support. The target was subdivided into three carefully cut out rings (1, 2, and 3; with external diameters of 1.4 cm; 5 cm; 10.2 cm, respectively). Each sample was analyzed with graphite furnace AAS. Lead values analysis performed for each ring yielded a linear relation between the firing distance (cm) and the logarithm of lead amounts (microg/cm(2)) in definite target areas (areas 2 + 3): [ln dPb(2+3) = a(0) + a(1)l]; where dPb(2+3) = lead microg/cm(2) of area 2 + 3; a(0) and a(1) are experimentally calculated; l = distance in cm.

  12. Determination of the Operating Envelope for a Direct Fired Fuel Cell Turbine Hybrid Using Hardware Based Simulation

    Energy Technology Data Exchange (ETDEWEB)

    David Tucker; Eric Liese; Randall Gemmen

    2009-02-10

    The operating range of a direct fired solid oxide fuel cell gas turbine (SOFC/GT) hybrid with bypass control of cathode airflow was determined using a hardware-based simulation facility designed and built by the U.S. Department of Energy, National Energy Technology Laboratory (NETL). Three methods of cathode airflow management using bypass valves in a hybrid power system were evaluated over the maximum range of operation. The cathode air flow was varied independently over the full range of operation of each bypass valve. Each operating point was taken at a steady state condition and was matched to the thermal, pressure and flow output of a corresponding fuel cell operation condition. Turbine electric load was also varied so that the maximum range of fuel cell operation could be studied, and a preliminary operating map could be made. Results are presented to show operating envelopes in terms of cathode air flow, fuel cell and turbine load, and compressor surge margin to be substantial.

  13. The Impact of Baryonic Physics on the Structure of Dark Matter Halos: the View from the FIRE Cosmological Simulations

    Science.gov (United States)

    Keung Chan, Tsang; Keres, Dusan; Oñorbe, Jose; Hopkins, Philip F.; Muratov, Alexander; Faucher-Giguere, Claude-Andre; Quataert, Eliot

    2016-06-01

    We study the distribution of cold dark matter (CDM) in cosmological simulations from the FIRE (Feedback In Realistic Environments) project, which incorporates explicit stellar feedback in the multi-phase ISM, with energetics from stellar population models. We find that stellar feedback, without ``fine-tuned'' parameters, greatly alleviates small-scale problems in CDM. Feedback causes bursts of star formation and outflows, altering the DM distribution. As a result, the inner slope of the DM halo profile (α) shows a strong mass dependence: profiles are shallow at Mh ˜ 1010-1011 M⊙ and steepen at higher/lower masses. The resulting core sizes and slopes are consistent with observations. Because the star formation efficiency, Ms/Mh is strongly halo mass dependent, a rapid change in α occurs around Mh ˜1010M⊙, (Ms˜106-107M⊙) as sufficient feedback energy becomes available to perturb the DM. Large cores are not established during the period of rapid growth of halos because of ongoing DM mass accumulation. Instead, cores require several bursts of star formation after the rapid buildup has completed. Stellar feedback dramatically reduces circular velocities in the inner kpc of massive dwarfs; this could be sufficient to explain the ``Too Big To Fail'' problem without invoking non-standard DM. Finally, feedback and baryonic contraction in Milky Way-mass halos produce DM profiles slightly shallower than the Navarro-Frenk-White profile, consistent with the normalization of the observed Tully-Fisher relation.

  14. Simulation and analysis of flexibly jointed manipulators

    Science.gov (United States)

    Murphy, Steve H.; Wen, John T.; Saridis, George M.

    1990-01-01

    Modeling, simulation, and analysis of robot manipulators with non-negligible joint flexibility are studied. A recursive Newton-Euler model of the flexibly jointed manipulator is developed with many advantages over the traditional Lagrange-Euler methods. The Newton-Euler approach leads to a method for the simulation of a flexibly jointed manipulator in which the number of computations grows linearly with the number of links. Additionally, any function for the flexibility between the motor and link may be used permitting the simulation of nonlinear effects, such as backlash, in a uniform manner for all joints. An analysis of the control problems for flexibly jointed manipulators is presented by converting the Newton-Euler model to a Lagrange-Euler form. The detailed structure available in the model is used to examine linearizing controllers and shows the dependency of the control on the choice of flexible model and structure of the manipulator.

  15. TRANSIMS: Transportation analysis and simulation system

    Energy Technology Data Exchange (ETDEWEB)

    Smith, L.; Beckman, R.; Baggerly, K. [and others

    1995-07-01

    This document summarizes the TRansportation ANalysis and SIMulation System (TRANSIMS) Project, the system`s major modules, and the project`s near-term plans. TRANSIMS will employ advanced computational and analytical techniques to create an integrated regional transportation systems analysis environment. The simulation environment will include a regional population of individual travelers and freight loads with travel activities and plans, whose individual interactions will be simulated on the transportation system, and whose environmental impact will be determined. We will develop an interim operational capability (IOC) for each major TRANSIMS module during the five-year program. When the IOC is ready, we will complete a specific case study to confirm the IOC features, applicability, and readiness.

  16. Stochastic Simulation Tool for Aerospace Structural Analysis

    Science.gov (United States)

    Knight, Norman F.; Moore, David F.

    2006-01-01

    Stochastic simulation refers to incorporating the effects of design tolerances and uncertainties into the design analysis model and then determining their influence on the design. A high-level evaluation of one such stochastic simulation tool, the MSC.Robust Design tool by MSC.Software Corporation, has been conducted. This stochastic simulation tool provides structural analysts with a tool to interrogate their structural design based on their mathematical description of the design problem using finite element analysis methods. This tool leverages the analyst's prior investment in finite element model development of a particular design. The original finite element model is treated as the baseline structural analysis model for the stochastic simulations that are to be performed. A Monte Carlo approach is used by MSC.Robust Design to determine the effects of scatter in design input variables on response output parameters. The tool was not designed to provide a probabilistic assessment, but to assist engineers in understanding cause and effect. It is driven by a graphical-user interface and retains the engineer-in-the-loop strategy for design evaluation and improvement. The application problem for the evaluation is chosen to be a two-dimensional shell finite element model of a Space Shuttle wing leading-edge panel under re-entry aerodynamic loading. MSC.Robust Design adds value to the analysis effort by rapidly being able to identify design input variables whose variability causes the most influence in response output parameters.

  17. The Use of a Narrative Simulation in Rural Residential Fire Prevention: A Preliminary Study in Changes of Behaviorial Intention

    Science.gov (United States)

    Goetz, William Clark

    2013-01-01

    Rural Kentucky residents suffer twice as many fire residential deaths than the national average. Fire prevention programs are primarily aimed at elementary school children however these children do not make the decisions nor take the precautions necessary to alter these conditions; their adult parents do. There is little research into the…

  18. Comparison of Interglacial fire dynamics in Southern Africa

    Science.gov (United States)

    Brücher, Tim; Daniau, Anne-Laure

    2016-04-01

    Responses of fire activity to a change in climate are still uncertain and biases exist by integrating this non-linear process into global modeling of the Earth system. Warming and regional drying can force fire activity in two opposite directions: an increase in fire in fuel supported ecosystems or a fire reduction in fuel-limited ecosystems. Therefore, climate variables alone can not be used to estimate the fire risk because vegetation variability is an important determinant of fire dynamics and responds itself to change in climate. Southern Africa (south of 20°S) paleofire history reconstruction obtained from the analysis of microcharcoal preserved in a deep-sea core located off Namibia reveals changes of fire activity on orbital timescales in the precession band. In particular, increase in fire is observed during glacial periods, and reduction of fire during interglacials such as the Eemian and the Holocene. The Holocene was characterized by even lower level of fire activity than Eemian. Those results suggest the alternance of grass-fueled fires during glacials driven by increase in moisture and the development of limited fueled ecosystems during interglacials characterized by dryness. Those results question the simulated increase in the fire risk probability projected for this region under a warming and drying climate obtained by Pechony and Schindell (2010). To explore the validity of the hypotheses we conducted a data-model comparison for both interglacials from 126.000 to 115.000 BP for the Eemian and from 8.000 to 2.000 BP for the Holocene. Data out of a transient, global modeling study with a Vegetation-Fire model of full complexity (JSBACH) is used, driven by a Climate model of intermediate complexity (CLIMBER). Climate data like precipitation and temperature as well as vegetation data like soil moisture, productivity (NPP) on plant functional type level are used to explain trends in fire activity. The comparison of trends in fire activity during the

  19. Radiographic simulations and analysis for ASCI

    Energy Technology Data Exchange (ETDEWEB)

    Aufderheide, M.; Stone, D.; VonWittenau, A.

    1998-12-18

    In this paper, the authors describe their work on developing quantitatively accurate radiographic simulation and analysis tools for ASCI hydro codes. they have extended the ability of HADES, the code which simulates radiography through a mesh, to treat the complex meshes used in ASCI calculations. The ultimate goal is to allow direct comparison between experimental radiographs and full physics simulated radiographs of ASCI calculations. They describe the ray-tracing algorithm they have developed for fast, accurate simulation of dynamic radiographs with the meshes used in ALE3D, an LLNL ASCI code. Spectral effects and material compositions are included. In addition to the newness of the mesh types, the distributed nature of domain decomposed problems requires special treatment by the radiographic code. Because of the size of such problems, they have parallelized the radiographic simulation, in order to have quick turnaround time. presently, this is done using the domain decomposition from the hydro code. They demonstrate good parallel scaling as the size of the problem is increased. They show a comparison between an experimental radiograph of a high explosive detonation and a simulated radiograph of an ALE3D calculation. They conclude with a discussion of future work.

  20. Aircraft Fire Protection Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Navy Aircraft Protection Laboratory provides complete test support for all Navy air vehicle fire protection systems.The facility allows for the simulation of a...

  1. Aircraft Fire Protection Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Navy Aircraft Protection Laboratory provides complete test support for all Navy air vehicle fire protection systems. The facility allows for the simulation of a...

  2. Performance Analysis Based on Timing Simulation

    DEFF Research Database (Denmark)

    Nielsen, Christian Dalsgaard; Kishinevsky, Michael

    1994-01-01

    Determining the cycle time and a critical cycle is a fundamental problem in the analysis of concurrent systems. We solve this problemusing timing simulation of an underlying Signal Graph (an extension of Marked Graphs). For a Signal Graph with n vertices and m arcs our algorithm has the polynomia...... time complexity O(b2m), where b is the number of vertices with initially marked in-arcs (typically b≪n). The algorithm has a clear semantic and a low descriptive complexity. We illustrate the use of the algorithm by applying it to performance analysis of asynchronous circuits.......Determining the cycle time and a critical cycle is a fundamental problem in the analysis of concurrent systems. We solve this problemusing timing simulation of an underlying Signal Graph (an extension of Marked Graphs). For a Signal Graph with n vertices and m arcs our algorithm has the polynomial...

  3. Wetland fire scar monitoring and analysis using archival Landsat data for the Everglades

    Science.gov (United States)

    Jones, John W.; Hall, Annette E.; Foster, Ann M.; Smith, Thomas J.

    2013-01-01

    The ability to document the frequency, extent, and severity of fires in wetlands, as well as the dynamics of post-fire wetland land cover, informs fire and wetland science, resource management, and ecosystem protection. Available information on Everglades burn history has been based on field data collection methods that evolved through time and differ by land management unit. Our objectives were to (1) design and test broadly applicable and repeatable metrics of not only fire scar delineation but also post-fire land cover dynamics through exhaustive use of the Landsat satellite data archives, and then (2) explore how those metrics relate to various hydrologic and anthropogenic factors that may influence post-fire land cover dynamics. Visual interpretation of every Landsat scene collected over the study region during the study time frame produced a new, detailed database of burn scars greater than 1.6 ha in size in the Water Conservation Areas and post-fire land cover dynamics for Everglades National Park fires greater than 1.6 ha in area. Median burn areas were compared across several landscape units of the Greater Everglades and found to differ as a function of administrative unit and fire history. Some burned areas transitioned to open water, exhibiting water depths and dynamics that support transition mechanisms proposed in the literature. Classification tree techniques showed that time to green-up and return to pre-burn character were largely explained by fire management practices and hydrology. Broadly applicable as they use data from the global, nearly 30-year-old Landsat archive, these methods for documenting wetland burn extent and post-fire land cover change enable cost-effective collection of new data on wetland fire ecology and independent assessment of fire management practice effectiveness.

  4. Investigating the impact of variations in particle size on heat flow from chaparral fires into soils using a laboratory based wildfire simulator

    Science.gov (United States)

    Karch, Adam Joseph

    It has been well established that under certain circumstances wildfire is capable of producing water repellent or hydrophobic soils. Hydrophobic soils can dramatically alter runoff and erosion processes and as such have been the subject of considerable research activity. Wildfires in chaparral vegetation are recognized as being particularly susceptible to hydrophobic soil development. A comparison of chaparral fire soil heat profiles from DeBano (1989) and Weirich (unpublished) indicates that under higher fire intensity situations in chaparral a different soil heating mechanism other than just conduction heating may be at work. In contrast to the slow moving low temperature increases expected in conduction heating a much faster heat pulse resulting in more rapid temperature rises and higher temperatures at depth can also occur in chaparral wildland fires. This suggests that a better understanding of the heat transfer processes that occur at extreme fire intensities is both important and is needed. The specific aim of this study was to observe heat flow under a variety of particle sizes using a laboratory based wildfire simulator operating at intensities and durations similar to those experienced in chaparral wildfires. The wildfire simulator system consisted of a propane burner array, an array of thermocouples to measure temperatures at varying locations and depths, and a data logging system to record the results of the heating experiments. Using the simulator homogenous sand, silt, clay, and heterogeneous clay loam were subjected to 600°C, 900°C, and 1200°C peak intensities with two different heating durations or treatments (H1 and H2). The heating levels and durations used were based on data from field based chaparral fire experimental temperature data previously collected by Weirich (unpublished). The system design allowed the user to control the intensity and duration of the heat treatments and the thermocouple sensor arrays measured temperatures at the

  5. Fire of Life′ analysis of heart rate variability during alpine skiing in Austria

    Directory of Open Access Journals (Sweden)

    Gerhard Litscher

    2010-01-01

    Full Text Available Background : Skiing is a very popular sport in Austria. Nevertheless, there is little information concerning online monitoring of bio-signals during alpine skiing in the mountains. Within the last years innovative scientific monitoring tools for evaluating features of neurocardial fitness have been developed. Aims : The goal of this study was to demonstrate the new ′Fire of Life′ heart rate variability analysis for the first time during alpine skiing. Volunteers and Methods : Continuous electrocardiographic monitoring over a period of 12 hours was performed simultaneously in two healthy volunteers using the same type of equipment (medilog AR12 systems. Two healthy volunteers (female, 20 years, and male, 51 years, both hobby skiers, were monitored simultaneously and continuously during two resting periods before and after active sport and also during alpine skiing. Altogether each participant covered 9,084 meters altitude difference within a time period of 6:14 hours. Total length of the downhill skiing was 45 kilometers. Results : Data acquisition was performed without any technical problems in both subjects. Poincaré plots of sequential R-R intervals (beat to beat variability show two ellipses of different shape and magnitude. During resting periods respiratory sinus arrhythmia and blood pressure effects can be clearly seen in the young female. The same effects, however markedly reduced, are obvious in the older volunteer. Conclusions : The present investigations during alpine skiing highlight the potential value of the ′Fire of Life′ heart rate variability monitoring even under difficult environmental conditions. The innovative kind of analysis helps to show how well the human body reacts to sport, stress and recovery.

  6. Fire of Life’ analysis of heart rate variability during alpine skiing in Austria

    Directory of Open Access Journals (Sweden)

    Gerhard Litscher

    2010-06-01

    Full Text Available Background: Skiing is a very popular sport in Austria. Nevertheless, there is little information concerning online monitoring of bio-signals during alpine skiing in the mountains. Within the last years innovative scientific monitoring tools for evaluating features of neurocardial fitness have been developed. Aims: The goal of this study was to demonstrate the new ‘Fire of Life’ heart rate variability analysis for the first time during alpine skiing. Volunteers and Methods: Continuous electrocardiographic monitoring over a period of 12 hours was performed simultaneously in two healthy volunteers using the same type of equipment (medilog AR12 systems. Two healthy volunteers (female, 20 years, and male, 51 years, both hobby skiers, were monitored simultaneously and continuously during two resting periods before and after active sport and also during alpine skiing. Altogether each participant covered 9,084 meters altitude difference within a time period of 6:14 hours. Total length of the downhill skiing was 45 kilometers. Results: Data acquisition was performed without any technical problems in both subjects. Poincaré plots of sequential R-R intervals (beat to beat variability show two ellipses of different shape and magnitude. During resting periods respiratory sinus arrhythmia and blood pressure effects can be clearly seen in the young female. The same effects, however markedly reduced, are obvious in the older volunteer. Conclusions: The present investigations during alpine skiing highlight the potential value of the ‘Fire of Life’ heart rate variability monitoring even under difficult environmental conditions. The innovative kind of analysis helps to show how well the human body reacts to sport, stress and recovery.

  7. Stochastic analysis for finance with simulations

    CERN Document Server

    Choe, Geon Ho

    2016-01-01

    This book is an introduction to stochastic analysis and quantitative finance; it includes both theoretical and computational methods. Topics covered are stochastic calculus, option pricing, optimal portfolio investment, and interest rate models. Also included are simulations of stochastic phenomena, numerical solutions of the Black–Scholes–Merton equation, Monte Carlo methods, and time series. Basic measure theory is used as a tool to describe probabilistic phenomena. The level of familiarity with computer programming is kept to a minimum. To make the book accessible to a wider audience, some background mathematical facts are included in the first part of the book and also in the appendices. This work attempts to bridge the gap between mathematics and finance by using diagrams, graphs and simulations in addition to rigorous theoretical exposition. Simulations are not only used as the computational method in quantitative finance, but they can also facilitate an intuitive and deeper understanding of theoret...

  8. Observationally-Motivated Analysis of Simulated Galaxies

    CERN Document Server

    Miranda, M S; Gibson, B K

    2015-01-01

    The spatial and temporal relationships between stellar age, kinematics, and chemistry are a fundamental tool for uncovering the physics driving galaxy formation and evolution. Observationally, these trends are derived using carefully selected samples isolated via the application of appropriate magnitude, colour, and gravity selection functions of individual stars; conversely, the analysis of chemodynamical simulations of galaxies has traditionally been restricted to the age, metallicity, and kinematics of `composite' stellar particles comprised of open cluster-mass simple stellar populations. As we enter the Gaia era, it is crucial that this approach changes, with simulations confronting data in a manner which better mimics the methodology employed by observers. Here, we use the \\textsc{SynCMD} synthetic stellar populations tool to analyse the metallicity distribution function of a Milky Way-like simulated galaxy, employing an apparent magnitude plus gravity selection function similar to that employed by the ...

  9. Confirmation via Analogue Simulation: A Bayesian Analysis

    CERN Document Server

    Dardashti, Radin; Thebault, Karim P Y; Winsberg, Eric

    2016-01-01

    Analogue simulation is a novel mode of scientific inference found increasingly within modern physics, and yet all but neglected in the philosophical literature. Experiments conducted upon a table-top 'source system' are taken to provide insight into features of an inaccessible 'target system', based upon a syntactic isomorphism between the relevant modelling frameworks. An important example is the use of acoustic 'dumb hole' systems to simulate gravitational black holes. In a recent paper it was argued that there exists circumstances in which confirmation via analogue simulation can obtain; in particular when the robustness of the isomorphism is established via universality arguments. The current paper supports these claims via an analysis in terms of Bayesian confirmation theory.

  10. Sensitivity Analysis of Multidisciplinary Rotorcraft Simulations

    Science.gov (United States)

    Wang, Li; Diskin, Boris; Biedron, Robert T.; Nielsen, Eric J.; Bauchau, Olivier A.

    2017-01-01

    A multidisciplinary sensitivity analysis of rotorcraft simulations involving tightly coupled high-fidelity computational fluid dynamics and comprehensive analysis solvers is presented and evaluated. An unstructured sensitivity-enabled Navier-Stokes solver, FUN3D, and a nonlinear flexible multibody dynamics solver, DYMORE, are coupled to predict the aerodynamic loads and structural responses of helicopter rotor blades. A discretely-consistent adjoint-based sensitivity analysis available in FUN3D provides sensitivities arising from unsteady turbulent flows and unstructured dynamic overset meshes, while a complex-variable approach is used to compute DYMORE structural sensitivities with respect to aerodynamic loads. The multidisciplinary sensitivity analysis is conducted through integrating the sensitivity components from each discipline of the coupled system. Numerical results verify accuracy of the FUN3D/DYMORE system by conducting simulations for a benchmark rotorcraft test model and comparing solutions with established analyses and experimental data. Complex-variable implementation of sensitivity analysis of DYMORE and the coupled FUN3D/DYMORE system is verified by comparing with real-valued analysis and sensitivities. Correctness of adjoint formulations for FUN3D/DYMORE interfaces is verified by comparing adjoint-based and complex-variable sensitivities. Finally, sensitivities of the lift and drag functions obtained by complex-variable FUN3D/DYMORE simulations are compared with sensitivities computed by the multidisciplinary sensitivity analysis, which couples adjoint-based flow and grid sensitivities of FUN3D and FUN3D/DYMORE interfaces with complex-variable sensitivities of DYMORE structural responses.

  11. Application of energy and exergy analysis to increase efficiency of a hot water gas fired boiler

    Directory of Open Access Journals (Sweden)

    Todorović Milena N.

    2014-01-01

    Full Text Available In engineering practice exergy can be used for technical and economic optimization of energy conversion processes. The problem of increasing energy consumption suggests that heating plants, i.e. hot water boilers, as energy suppliers for household heating should be subjected to exergy and energy analysis. Heating plants are typically designed to meet energy demands, without the distinguished difference between quality and quantity of the produced heat. In this paper, the energy and exergy analysis of a gas fired hot water boiler is conducted. Energy analysis gives only quantitative results, while exergy analysis provides an insight into the actually available useful energy with respect to the system environment. In this paper, a hot water boiler was decomposed into control volumes with respect to its functional components. Energy and exergy of the created physical model of the hot water boiler is performed and destruction of exergy and energy loss in each of the components is calculated. The paper describes the current state of energy and exergy efficiency of the hot water boiler. The obtained results are analyzed and used to investigate possibilities for improvement of availability and reliability of the boiler. A comparison between the actual and the proposed more reliable solution is made.

  12. Categorical modeling on electrical anomaly of room-and-pillar coal mine fires and application for field electrical resistivity tomography

    Science.gov (United States)

    Song, Wujun; Wang, Yanming; Shao, Zhenlu

    2017-01-01

    In order to improve the accuracy of fire area delineation in coalfield with electrical prospecting, the categorical geoelectric models of coal fires are established according to geological and mining conditions. The room-and-pillar coal mine fires are divided into three types which are coal seam fire, goaf fire and subsidence area fire, respectively, and forward electrical simulations and inversion analysis of each type of coal fire are implemented. Simulation results show that the resistance anomalies of goaf fires exist around one and a half to two times higher than background field, in contrast, coal seam and subsidence area fires performance low resistivity response which are roughly half to two-third of background field resistivity, respectively. Identification of different fire types and delineation of coal fire areas are further presented. The inversion results which are validated by borehole survey prove that the presented method could eliminate the omission of coal fires with high resistance anomaly and provide a novel reference for fire extinguishing in the future.

  13. 矿井胶带巷火灾风流稳定性模拟与控制技术研究%Stability simulation and control technology of airflow during fire in mine belt roadway

    Institute of Scientific and Technical Information of China (English)

    张圣柱; 程卫民; 张如明; 刘星魁

    2011-01-01

    通过对风流流体的动力学分析,给出了三维湍流求解的标准后κ-ε两方程模型.应用Mixture多相流对火灾灾变过程中产生的污染物进行设定,综合考虑火灾过程中的热量辐射与组分传输,采用SIMPLE算法对孔庄煤矿1号胶带巷火灾灾变时不同进风量下巷道内的风流流动状态进行了模拟,得到了温度和污染物等参数在巷道内的分布,为灾变信息监测和自动控风设施的设置提供了依据.在掌握火灾时期风流稳定性的基础上,建立了胶带巷火灾灾变预警与控制系统,并在孔庄煤矿进行了应用,有助于胶带巷火灾时期的灾变控制和有效避灾.%According to fluid dynamics analysis during the fire,the criteria k-ε two-equation model for solving threedimensional turbulent was determined, the pollutants generated in the fire disaster were set by adopting Mixture multiphase flow, the heat radiation and composition transfer during fire were considered, the SIMPLE algorithm was used for simulating airflow flowing state inside the tunnel under different inlet air volumes with regard to the actual situation of No. 1 belt roadway of Kongzhuang Coal Mine, and the distribution of temperature and pollutants in the belt roadway were obtained,which provided evidence for monitoring of disaster information and setting of automatic airflow control facilities. On the basis of mastering airflow stability during fire, the fire early warning and control system of belt roadway was established and applied to Kongzhuang Coal Mine,which was helpful to disaster control and avoiding during belt roadway fire.

  14. Methodology for Validating Building Energy Analysis Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Judkoff, R.; Wortman, D.; O' Doherty, B.; Burch, J.

    2008-04-01

    The objective of this report was to develop a validation methodology for building energy analysis simulations, collect high-quality, unambiguous empirical data for validation, and apply the validation methodology to the DOE-2.1, BLAST-2MRT, BLAST-3.0, DEROB-3, DEROB-4, and SUNCAT 2.4 computer programs. This report covers background information, literature survey, validation methodology, comparative studies, analytical verification, empirical validation, comparative evaluation of codes, and conclusions.

  15. National Infrastructure Simulation and Analysis Center Overview

    Energy Technology Data Exchange (ETDEWEB)

    Berscheid, Alan P. [Los Alamos National Laboratory

    2012-07-30

    National Infrastructure Simulation and Analysis Center (NISAC) mission is to: (1) Improve the understanding, preparation, and mitigation of the consequences of infrastructure disruption; (2) Provide a common, comprehensive view of U.S. infrastructure and its response to disruptions - Scale & resolution appropriate to the issues and All threats; and (3) Built an operations-tested DHS capability to respond quickly to urgent infrastructure protection issues.

  16. Simulation study of passive target motion analysis

    Institute of Scientific and Technical Information of China (English)

    HU Youfeng; JIAO Binli

    2003-01-01

    In this paper, the problem of underwater passive target motion analysis (TMA) in three dimensions is discussed using the measurements of passive bearings and elevation and frequency on the condition that acoustic source and observer are in different horizontal planes. Simulation results with both of the PLE (pseudo-linear estimation) and MLE (Maximum likelihood estimation) show that the TMA method is effective in oceanic environment. Its error covariance curves tend to its Cramer-Rao lower bounds.

  17. 2D and 3D Eulerian Simulations of the Dynamics and Gas and Aerosol Chemistry of a Young Biomass Burning Smoke Plume from a Savannah Fire

    Science.gov (United States)

    Alvarado, M. J.; Prinn, R. G.

    2007-12-01

    The growth of aerosol particles and production of ozone in young smoke plumes is the result of a complex interaction between the mean flow in the smoke plume, turbulent diffusion, gas-phase oxidation, coagulation, and mass transfer between phases. Models allow us to separate the effects of these processes and predict their impact on the global environment. We present the results of two and three-dimensional Eulerian simulations of the dynamics and chemistry of the smoke plume formed by the Timbavati savannah fire studied during SAFARI 2000 (Hobbs et al., 2003, JGR, doi:10.1029/2002JD002352). The dynamical model is an extension of an Eulerian cloud-resolving model that has previously been used to study the role of deep convective clouds on tropospheric chemistry (Wang and Prinn, 2000, JGR, 105(D17) 22,269-22,297). The model includes a source of sensible heat, gases, and particles at the surface to simulate the savannah fire. The new gas and aerosol chemistry model includes heterogeneous chemistry, kinetic mass transfer, coagulation and the formation of secondary organic and inorganic aerosol. Photolysis rates are calculated based on the solution of the radiative transfer equation within the plume, including the scattering and absorption of radiation by the smoke aerosols. Our preliminary 2D Eulerian results using standard chemistry and UV fluxes show that the model can simulate the lower but not the higher levels of O3 observed. Also, the simulated 2D O3 field shows a wave-like pattern in the downwind direction, even though the emissions from the fire are held constant. This suggests that plume heterogeneity in the downwind direction may account for some of the observed variability in O3. We will present results of runs incorporating higher resolution calculation of photolysis rates, heterogeneous HONO formation, and gas phase reactions involving the uncharacterized organic compounds observed in the gas phase of the Timbavati plume in order to better simulate these

  18. A spatio-temporal analysis of fire recurrence and extent for semi-arid savanna ecosystems in Southern Africa using moderate-resolution satellite imagery.

    Science.gov (United States)

    Pricope, Narcisa G; Binford, Michael W

    2012-06-15

    Savanna ecosystems are semi-arid and fire-prone. Increasing temperatures and decreasing precipitation in Southern Africa will probably have a series of strong impacts on the various components of fire regimes in these ecosystems that will, in turn, affect their ecology, structure, and function. This paper presents a geospatial analysis to quantify changes in fire frequency, seasonality and spatial distribution during the last decade and creates a fire return interval map for the core area of the Kavango-Zambezi Transfrontier Conservation Area, which spans five Southern African countries and is the largest cooperative multistate conservation region in the world. To disentangle the relative contribution of environmental variability from country-specific land management decisions in driving changes in fire regimes, we use two different products from the MODIS Terra platform (Active Fire and Burned Area products), TRMM precipitation data and the Multivariate ENSO Index data to analyze change in fire regimes among the five countries, differentiating between different land uses such as protected areas, forest reserves, and communal lands and accounting for specific changes in fire management policies. There are significant differences in fire frequencies between countries with more effective fire management (Botswana and Zimbabwe) and countries where anthropogenic, mainly early-dry season, burning is largely uncontrolled (Namibia, Angola, and Zambia), both within and outside protected areas, while all countries and land-use units show an overall increasing trend in fire occurrences. Large fire occurrences increased up to 200% in the period before the beginning of the natural fire season in Namibia, where a new prescribed burn policy was introduced in 2006, while the other countries show a slightly different shift in seasonality of increasing fire occurrences mainly during the dry season. The mean size of fires also increases significantly across all land uses despite

  19. Analysis of the evaporative towers cooling system of a coal-fired power plant

    Directory of Open Access Journals (Sweden)

    Laković Mirjana S.

    2012-01-01

    Full Text Available The paper presents a theoretical analysis of the cooling system of a 110 MW coal-fired power plant located in central Serbia, where eight evaporative towers cool down the plant. An updated research on the evaporative tower cooling system has been carried out to show the theoretical analysis of the tower heat and mass balance, taking into account the sensible and latent heat exchanged during the processes which occur inside these towers. Power plants which are using wet cooling towers for cooling condenser cooling water have higher design temperature of cooling water, thus the designed condensing pressure is higher compared to plants with a once-through cooling system. Daily and seasonal changes further deteriorate energy efficiency of these plants, so it can be concluded that these plants have up to 5% less efficiency compared to systems with once-through cooling. The whole analysis permitted to evaluate the optimal conditions, as far as the operation of the towers is concerned, and to suggest an improvement of the plant. Since plant energy efficiency improvement has become a quite common issue today, the evaluation of the cooling system operation was conducted under the hypothesis of an increase in the plant overall energy efficiency due to low cost improvement in cooling tower system.

  20. FIRE PROTECTION SYSTEMS AND TECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    Aristov Denis Ivanovich

    2016-03-01

    Full Text Available The All-Russian Congress “Fire Stop Moscow” was de-voted to the analysis of the four segments of the industry of fire protection systems and technologies: the design of fire protec-tion systems, the latest developments and technologies of active and passive fire protection of buildings, the state and the devel-opment of the legal framework, the practice of fire protection of buildings and structures. The forum brought together the repre-sentatives of the industry of fire protection systems, scientists, leading experts, specialists in fire protection and representatives of construction companies from different regions of Russia. In parallel with the Congress Industrial Exhibition of fire protection systems, materials and technology was held, where manufacturers presented their products. The urgency of the “Fire Stop Moscow” Congress in 2015 organized by the Congress Bureau ODF Events lies primarily in the fact that it considered the full range of issues related to the fire protection of building and construction projects; studied the state of the regulatory framework for fire safety and efficiency of public services, research centers, private companies and busi-nesses in the area of fire safety. The main practical significance of the event which was widely covered in the media space, was the opportunity to share the views and information between management, science, and practice of business on implementing fire protection systems in the conditions of modern economic relations and market realities. : congress, fire protection, systems, technologies, fire protection systems, exhibition

  1. Fire disaster preparedness and situational analysis in higher learning institutions of Tanzania

    Directory of Open Access Journals (Sweden)

    Jacob M. Kihila

    2017-01-01

    Full Text Available Fire disasters are accompanied with devastating impact affecting both lives and properties. The magnitude of the impacts has been severe in places with low levels of fire disaster preparedness. A study was conducted in Dar es Salaam, Tanzania, to investigate the level of fire disaster preparedness considering the availability and condition of firefighting facilities as well as the knowledge on fire management among the selected 10 higher learning institutions. Information for the buildings was obtained from the interviews with the managers of the buildings and field observations; information on the user’s preparedness was obtained from interviews using structured questionnaire conducted with the users of the buildings including the visitors. Results from the studied buildings indicated that 60% of the firefighting facilities were not regularly serviced; 50% stored some hazardous materials; 70% of them had not enough water storage for firefighting purposes; 60% had no identifiable fire assembly points; and 90% of the sessions conducted in the buildings involved more than 100 people in a single venue. Further results indicated that 51% of the respondents were not able to operate the installed firefighting facilities; 80.7% of the respondents had never received any training on firefighting and prevention; 95.6% of the respondents had never participated in any fire drills; and 81.5% of them were not aware of the fire responder’s contacts. General situation indicated that higher learning institutions are not well prepared to manage fire outbreaks suggesting that plans to rectify the situation are imperative.

  2. How knowledge influences a MCDM analysis: WOCAT Portuguese experience on prevention of forest fires

    Science.gov (United States)

    Carreiras, M.; Ferreira, A. J. D.; Moreira, J.; Esteves, T. C. J.; Valente, S.; Soares, J.; Coelho, C. O. A.; Schwilch, G.; Bachmann, F.

    2012-04-01

    degradation processes. Affecting large areas every year, they also have serious human, socio-economic and psychological impacts. Under the DESIRE project two Portuguese study sites were selected - Góis e Mação. Both study sites are located in Central Portugal and are frequently affected by forest fires. Nowadays different types of solutions applied at the local level are related with the prevention, combat and mitigation of forest fires. At a higher level of analysis the main solution is related with the diversification of the soil uses, mainly by the mixture of cropland, pastures and forest areas. But the selection of the technique isn't so far an open, participative and effective process, and the interests of land users are not represented most of the time. This paper aims to present WOCAT approach and results to forest fire prevention in Portugal considering stakeholder's perspectives and policy recommendations and it's evolution based on an increased of knowledge.

  3. Simulation based analysis of laser beam brazing

    Science.gov (United States)

    Dobler, Michael; Wiethop, Philipp; Schmid, Daniel; Schmidt, Michael

    2016-03-01

    Laser beam brazing is a well-established joining technology in car body manufacturing with main applications in the joining of divided tailgates and the joining of roof and side panels. A key advantage of laser brazed joints is the seam's visual quality which satisfies highest requirements. However, the laser beam brazing process is very complex and process dynamics are only partially understood. In order to gain deeper knowledge of the laser beam brazing process, to determine optimal process parameters and to test process variants, a transient three-dimensional simulation model of laser beam brazing is developed. This model takes into account energy input, heat transfer as well as fluid and wetting dynamics that lead to the formation of the brazing seam. A validation of the simulation model is performed by metallographic analysis and thermocouple measurements for different parameter sets of the brazing process. These results show that the multi-physical simulation model not only can be used to gain insight into the laser brazing process but also offers the possibility of process optimization in industrial applications. The model's capabilities in determining optimal process parameters are exemplarily shown for the laser power. Small deviations in the energy input can affect the brazing results significantly. Therefore, the simulation model is used to analyze the effect of the lateral laser beam position on the energy input and the resulting brazing seam.

  4. Preparation, certification and interlaboratory analysis of workplace air filters spiked with high-fired beryllium oxide.

    Science.gov (United States)

    Oatts, Thomas J; Hicks, Cheryl E; Adams, Amy R; Brisson, Michael J; Youmans-McDonald, Linda D; Hoover, Mark D; Ashley, Kevin

    2012-02-01

    Occupational sampling and analysis for multiple elements is generally approached using various approved methods from authoritative government sources such as the National Institute for Occupational Safety and Health (NIOSH), the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA), as well as consensus standards bodies such as ASTM International. The constituents of a sample can exist as unidentified compounds requiring sample preparation to be chosen appropriately, as in the case of beryllium in the form of beryllium oxide (BeO). An interlaboratory study was performed to collect analytical data from volunteer laboratories to examine the effectiveness of methods currently in use for preparation and analysis of samples containing calcined BeO powder. NIST SRM(®) 1877 high-fired BeO powder (1100 to 1200 °C calcining temperature; count median primary particle diameter 0.12 μm) was used to spike air filter media as a representative form of beryllium particulate matter present in workplace sampling that is known to be resistant to dissolution. The BeO powder standard reference material was gravimetrically prepared in a suspension and deposited onto 37 mm mixed cellulose ester air filters at five different levels between 0.5 μg and 25 μg of Be (as BeO). Sample sets consisting of five BeO-spiked filters (in duplicate) and two blank filters, for a total of twelve unique air filter samples per set, were submitted as blind samples to each of 27 participating laboratories. Participants were instructed to follow their current process for sample preparation and utilize their normal analytical methods for processing samples containing substances of this nature. Laboratories using more than one sample preparation and analysis method were provided with more than one sample set. Results from 34 data sets ultimately received from the 27 volunteer laboratories were subjected to applicable statistical analyses. The observed

  5. Modelling and Simulation of Ship Fire Control System%舰载火控系统的建模与仿真

    Institute of Scientific and Technical Information of China (English)

    顾浩

    2000-01-01

    This paper discusses the role of modelling and simulation technology in the development ofnew weapon system. It also introduces the integrative WISE modelling /simulation developmentenvironment and simulation software of JARI in China, and describes modelling and digital sumulationmethod for the ship fire control system. A technical way to support new fire control system effectivenessevaluation by using Distributed Interactive Simulation (DIS) is given%探讨了建模与仿真技术在新型武器系统研制中的作用地位;介绍了WISE一体化建模/仿真开发环境及仿真软件,描述了新型舰载火控系统的建模与数字仿真方法,给出了采用分布交互式仿真(DIS)技术支持新型舰载火控系统进行效能评估的技术途径

  6. Optoelectronic Devices Advanced Simulation and Analysis

    CERN Document Server

    Piprek, Joachim

    2005-01-01

    Optoelectronic devices transform electrical signals into optical signals and vice versa by utilizing the sophisticated interaction of electrons and light within micro- and nano-scale semiconductor structures. Advanced software tools for design and analysis of such devices have been developed in recent years. However, the large variety of materials, devices, physical mechanisms, and modeling approaches often makes it difficult to select appropriate theoretical models or software packages. This book presents a review of devices and advanced simulation approaches written by leading researchers and software developers. It is intended for scientists and device engineers in optoelectronics, who are interested in using advanced software tools. Each chapter includes the theoretical background as well as practical simulation results that help to better understand internal device physics. The software packages used in the book are available to the public, on a commercial or noncommercial basis, so that the interested r...

  7. Ecological Impacts of the Cerro Grande Fire: Predicting Elk Movement and Distribution Patterns in Response to Vegetative Recovery through Simulation Modeling October 2005

    Energy Technology Data Exchange (ETDEWEB)

    Rupp, Susan P. [Texas Tech Univ., Lubbock, TX (United States)

    2005-10-01

    In May 2000, the Cerro Grande Fire burned approximately 17,200 ha in north-central New Mexico as the result of an escaped prescribed burn initiated by Bandelier National Monument. The interaction of large-scale fires, vegetation, and elk is an important management issue, but few studies have addressed the ecological implications of vegetative succession and landscape heterogeneity on ungulate populations following large-scale disturbance events. Primary objectives of this research were to identify elk movement pathways on local and landscape scales, to determine environmental factors that influence elk movement, and to evaluate movement and distribution patterns in relation to spatial and temporal aspects of the Cerro Grande Fire. Data collection and assimilation reflect the collaborative efforts of National Park Service, U.S. Forest Service, and Department of Energy (Los Alamos National Laboratory) personnel. Geographic positioning system (GPS) collars were used to track 54 elk over a period of 3+ years and locational data were incorporated into a multi-layered geographic information system (GIS) for analysis. Preliminary tests of GPS collar accuracy indicated a strong effect of 2D fixes on position acquisition rates (PARs) depending on time of day and season of year. Slope, aspect, elevation, and land cover type affected dilution of precision (DOP) values for both 2D and 3D fixes, although significant relationships varied from positive to negative making it difficult to delineate the mechanism behind significant responses. Two-dimensional fixes accounted for 34% of all successfully acquired locations and may affect results in which those data were used. Overall position acquisition rate was 93.3% and mean DOP values were consistently in the range of 4.0 to 6.0 leading to the conclusion collar accuracy was acceptable for modeling purposes. SAVANNA, a spatially explicit, process-oriented ecosystem model, was used to simulate successional dynamics. Inputs to the

  8. NONLINEAR FINITE ELEMENT ANALYSIS OF REINFORCED CONCRETE BEAMS IN FIRE%火灾下钢筋混凝土梁非线性有限元分析

    Institute of Scientific and Technical Information of China (English)

    廖艳芬; 漆雅庆; 马晓茜

    2011-01-01

    Through numerical simulation of the whole process of heat transfer and deformation on three different conditions groups of reinfored concrete beams,it is analysed the non-linear changing process of the temperature distribution and structural deformation of reinfored concrete beams in fire.Based on thermal characteristics and the temperature-strain-stress constitutive characteristics of reinforced concrete beams it is analysied the influences of the evolutionary processes of the reinfored concrete beams temperature distribution in fire,as well as reinforcement ratio,initial load and heating time on the fire resistance capacity of reinfored concrete beams.Results show that the overall instability of the beams is caused by the reduction of material strength,weight and the initial load,as well as the internal stress because of the uneven heating in fire.The influences of initial load on the residual bearing capacity is little,but increase the number of rebars can effectively improve the fire resistance capacity of reinforced concrete beams.%为分析钢筋混凝土梁在火灾过程中的温度分布、结构变形非线性变化过程,在三组不同条件下对火灾后钢筋混凝土梁构件内部传热及变形过程进行全过程仿真。基于钢筋混凝土热工特性、温度-应变-应力本构特性,分析钢筋混凝土梁在受火时的温度分布演化过程,以及配筋率、初始载荷和受火时间等参数对钢筋混凝土梁防火承载力的影响。结果表明:火灾中材料强度的降低,自重和初始载荷以及不均匀升温引起的内部应力共同作用引起了构件的整体失稳。初始载荷对梁剩余承载力的影响不大,提高混凝土中钢筋数量能有效地提高钢筋混凝土梁的防火承载力。

  9. A Simulation Study on the Effects of Dendritic Morphology on Layer V Prefontal Pyramidal Cell Firing Behavior

    Directory of Open Access Journals (Sweden)

    Maria ePsarrou

    2014-09-01

    Full Text Available Pyramidal cells, the most abundant neurons in neocortex, exhibit significant structural variability across different brain areas and layers in different species. Moreover, in response to a somatic step current, these cells display a range of firing behaviors, the most common being (1 repetitive action potentials (Regular Spiking - RS, and (2 an initial cluster of 2-5 action potentials with short ISIs followed by single spikes (Intrinsic Bursting - IB. A correlation between firing behavior and dendritic morphology has recently been reported. In this work we use computational modeling to investigate quantitatively the effects of the basal dendritic tree morphology on the firing behavior of 112 three-dimensional reconstructions of layer V PFC rat pyramidal cells. Particularly, we focus on how different morphological (diameter, total length, volume and branch number and passive (Mean Electrotonic Path length features of basal dendritic trees shape somatic firing when the spatial distribution of ionic mechanisms in the basal dendritic trees is uniform or non-uniform. Our results suggest that total length, volume and branch number are the best morphological parameters to discriminate the cells as RS or IB, regardless of the distribution of ionic mechanisms in basal trees. The discriminatory power of total length, volume and branch number remains high in the presence of different apical dendrites. These results suggest that morphological variations in the basal dendritic trees of layer V pyramidal neurons in the PFC influence their firing patterns in a predictive manner and may in turn influence the information processing capabilities of these neurons.

  10. Sample Analysis at Mars Instrument Simulator

    Science.gov (United States)

    Benna, Mehdi; Nolan, Tom

    2013-01-01

    The Sample Analysis at Mars Instrument Simulator (SAMSIM) is a numerical model dedicated to plan and validate operations of the Sample Analysis at Mars (SAM) instrument on the surface of Mars. The SAM instrument suite, currently operating on the Mars Science Laboratory (MSL), is an analytical laboratory designed to investigate the chemical and isotopic composition of the atmosphere and volatiles extracted from solid samples. SAMSIM was developed using Matlab and Simulink libraries of MathWorks Inc. to provide MSL mission planners with accurate predictions of the instrument electrical, thermal, mechanical, and fluid responses to scripted commands. This tool is a first example of a multi-purpose, full-scale numerical modeling of a flight instrument with the purpose of supplementing or even eliminating entirely the need for a hardware engineer model during instrument development and operation. SAMSIM simulates the complex interactions that occur between the instrument Command and Data Handling unit (C&DH) and all subsystems during the execution of experiment sequences. A typical SAM experiment takes many hours to complete and involves hundreds of components. During the simulation, the electrical, mechanical, thermal, and gas dynamics states of each hardware component are accurately modeled and propagated within the simulation environment at faster than real time. This allows the simulation, in just a few minutes, of experiment sequences that takes many hours to execute on the real instrument. The SAMSIM model is divided into five distinct but interacting modules: software, mechanical, thermal, gas flow, and electrical modules. The software module simulates the instrument C&DH by executing a customized version of the instrument flight software in a Matlab environment. The inputs and outputs to this synthetic C&DH are mapped to virtual sensors and command lines that mimic in their structure and connectivity the layout of the instrument harnesses. This module executes

  11. Fire forum 2006

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    The conference contains 18 presentations on various aspects of fire prevention and protection within the power production plants and industry, safety of building constructions, cable and transformer problems, risk and safety evaluation methods, management aspects, relevant Norwegian and Icelandic laws and regulations and oil analysis. Some examples of fires and explosions are also presented. (tk)

  12. HAZARDS OF THERMAL EXPANSION FOR RADIOLOGICAL CONTAINER ENGULFED IN FIRE

    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen

    2013-05-01

    Fire accidents pose a serious threat to nuclear facilities. It is imperative that transport casks or shielded containers designed to transport/contain radiological materials have the ability to withstand a hypothetical fire. A numerical simulation was performed for a shielded container constructed of stainless steel and lead engulfed in a hypothetical fire as outlined by 10 CFR §71.73. The purpose of this analysis was to determine the thermal response of the container during and after the fire. The thermal model shows that after 30 minutes of fire, the stainless steel will maintain its integrity and not melt. However, the lead shielding will melt since its temperature exceeds the melting point. Due to the method of construction of the container under consideration, ample void space must be provided to allow for thermal expansion of the lead upon heating and melting, so as to not overstress the weldment.

  13. Space Debris Attitude Simulation - IOTA (In-Orbit Tumbling Analysis)

    Science.gov (United States)

    Kanzler, R.; Schildknecht, T.; Lips, T.; Fritsche, B.; Silha, J.; Krag, H.

    Today, there is little knowledge on the attitude state of decommissioned intact objects in Earth orbit. Observational means have advanced in the past years, but are still limited with respect to an accurate estimate of motion vector orientations and magnitude. Especially for the preparation of Active Debris Removal (ADR) missions as planned by ESA's Clean Space initiative or contingency scenarios for ESA spacecraft like ENVISAT, such knowledge is needed. The In-Orbit Tumbling Analysis tool (IOTA) is a prototype software, currently in development within the framework of ESA's “Debris Attitude Motion Measurements and Modelling” project (ESA Contract No. 40000112447), which is led by the Astronomical Institute of the University of Bern (AIUB). The project goal is to achieve a good understanding of the attitude evolution and the considerable internal and external effects which occur. To characterize the attitude state of selected targets in LEO and GTO, multiple observation methods are combined. Optical observations are carried out by AIUB, Satellite Laser Ranging (SLR) is performed by the Space Research Institute of the Austrian Academy of Sciences (IWF) and radar measurements and signal level determination are provided by the Fraunhofer Institute for High Frequency Physics and Radar Techniques (FHR). Developed by Hyperschall Technologie Göttingen GmbH (HTG), IOTA will be a highly modular software tool to perform short- (days), medium- (months) and long-term (years) propagation of the orbit and attitude motion (six degrees-of-freedom) of spacecraft in Earth orbit. The simulation takes into account all relevant acting forces and torques, including aerodynamic drag, solar radiation pressure, gravitational influences of Earth, Sun and Moon, eddy current damping, impulse and momentum transfer from space debris or micro meteoroid impact, as well as the optional definition of particular spacecraft specific influences like tank sloshing, reaction wheel behaviour

  14. Uncertainty analysis of steady state incident heat flux measurements in hydrocarbon fuel fires.

    Energy Technology Data Exchange (ETDEWEB)

    Nakos, James Thomas

    2005-12-01

    The objective of this report is to develop uncertainty estimates for three heat flux measurement techniques used for the measurement of incident heat flux in a combined radiative and convective environment. This is related to the measurement of heat flux to objects placed inside hydrocarbon fuel (diesel, JP-8 jet fuel) fires, which is very difficult to make accurately (e.g., less than 10%). Three methods will be discussed: a Schmidt-Boelter heat flux gage; a calorimeter and inverse heat conduction method; and a thin plate and energy balance method. Steady state uncertainties were estimated for two types of fires (i.e., calm wind and high winds) at three times (early in the fire, late in the fire, and at an intermediate time). Results showed a large uncertainty for all three methods. Typical uncertainties for a Schmidt-Boelter gage ranged from {+-}23% for high wind fires to {+-}39% for low wind fires. For the calorimeter/inverse method the uncertainties were {+-}25% to {+-}40%. The thin plate/energy balance method the uncertainties ranged from {+-}21% to {+-}42%. The 23-39% uncertainties for the Schmidt-Boelter gage are much larger than the quoted uncertainty for a radiative only environment (i.e ., {+-}3%). This large difference is due to the convective contribution and because the gage sensitivities to radiative and convective environments are not equal. All these values are larger than desired, which suggests the need for improvements in heat flux measurements in fires.

  15. Analysis of the personnel casualty reasons and evacuating behavior in the fire%火灾中人员伤亡原因及疏散行为

    Institute of Scientific and Technical Information of China (English)

    庞建军

    2012-01-01

    根据火灾调查取得的有关参数,使用FDS火灾模拟软件对火灾过程进行了模拟,取得了楼梯间内一氧化碳、二氧化碳、氧气含量及能见度等模拟数据.燃烧产物毒害性、高温烟气、烟气减光性是火灾中致人伤亡的原因.针对火灾中人员的疏散行为,分析了火灾事故教训,提出了预防伤亡的措施.%The paper uses the software of Fire Dynamics Simulator to simulate the course of fire by the parameter from the investigation the fire. FDS calculates the concentration of COi CO2 > O2 and the visibility in the course of fire. It is the poison from the products of combustion. the smoke and gas with high temperature and the strong smoke that make people die and injured in the fire. It analyzes the lessons of the fire accidents, puts forward the prevention measures of personnel casualty in the fire by analyzing of evacuating behavior.

  16. Assessment of sealed fire states by fire characteristic

    Institute of Scientific and Technical Information of China (English)

    YUAN Shu-jie; SZLAZAK Nikodem; OBRACAJ Dariusz

    2006-01-01

    The paper presented assessment of sealed fire states in underground coal mines by so-called "fire characteristic", which graphically described tendencies of fire gas components - oxygen, nitrogen, carbon dioxide, carbon monoxide and hydrocarbons - in time. In order to mark gas components tendencies in time the authors applied the time series analysis. The case studied confirmed, that analysis of fire gas components tendencies in time and their correlation allow to elicit proper conclusions about fire state assessment. Assessment of fire states based on single value of fire indexes without considering their trends in time and correlation between trends of gas components would give wrong results. The suggested method can appropriately indicate fire states in a sealed area.

  17. Fire phenomena and nonlinearity (II). Catastrophic fire dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Z. [University of Science and Technology, Hefei (China). State Key Laboratory of Fire Science

    2000-09-01

    As one of the most important non-linear mechanisms to cause fire or exacerbate fire disaster, there is a great deal of catastrophe behaviours existing in fire processes. The main tasks of the study of catastrophic fire dynamics are: 1) analysis of the catastrophe mechanisms of discontinuity behaviours in fire systems; 2) investigation of the controlling methods of discontinuity behaviours of fire system; 3) qualitative analysis of the dynamical characteristics of fire systems; and 4) catastrophe classifying of discontinuity phenomena in fire system. The other disciplines, such as physics, chemistry, biology, geoscience, astronomy, or even social sciences (for instance, political, economics, strategics and management science), may also take the similar method to establish the corresponding branch discipline of catastrophe science and catastrophe classification method. It is pointed out that an ignition behaviour of the uniform temperature thermal explosion system under the control of radiation has cusp catastrophe mechanism. 10 refs., 3 figs.

  18. On the rejection-based algorithm for simulation and analysis of large-scale reaction networks

    Energy Technology Data Exchange (ETDEWEB)

    Thanh, Vo Hong, E-mail: vo@cosbi.eu [The Microsoft Research-University of Trento Centre for Computational and Systems Biology, Piazza Manifattura 1, Rovereto 38068 (Italy); Zunino, Roberto, E-mail: roberto.zunino@unitn.it [Department of Mathematics, University of Trento, Trento (Italy); Priami, Corrado, E-mail: priami@cosbi.eu [The Microsoft Research-University of Trento Centre for Computational and Systems Biology, Piazza Manifattura 1, Rovereto 38068 (Italy); Department of Mathematics, University of Trento, Trento (Italy)

    2015-06-28

    Stochastic simulation for in silico studies of large biochemical networks requires a great amount of computational time. We recently proposed a new exact simulation algorithm, called the rejection-based stochastic simulation algorithm (RSSA) [Thanh et al., J. Chem. Phys. 141(13), 134116 (2014)], to improve simulation performance by postponing and collapsing as much as possible the propensity updates. In this paper, we analyze the performance of this algorithm in detail, and improve it for simulating large-scale biochemical reaction networks. We also present a new algorithm, called simultaneous RSSA (SRSSA), which generates many independent trajectories simultaneously for the analysis of the biochemical behavior. SRSSA improves simulation performance by utilizing a single data structure across simulations to select reaction firings and forming trajectories. The memory requirement for building and storing the data structure is thus independent of the number of trajectories. The updating of the data structure when needed is performed collectively in a single operation across the simulations. The trajectories generated by SRSSA are exact and independent of each other by exploiting the rejection-based mechanism. We test our new improvement on real biological systems with a wide range of reaction networks to demonstrate its applicability and efficiency.

  19. Geospatial modeling of fire-size distributions in historical low-severity fire regimes

    Science.gov (United States)

    McKenzie, D.; Kellogg, L. B.; Larkin, N. K.

    2006-12-01

    Low-severity fires are recorded by fire-scarred trees. These records can provide temporal depth for reconstructing fire history because one tree may record dozens of separate fires over time, thereby providing adequate sample size for estimating fire frequency. Estimates of actual fire perimeters from these point-based records are uncertain, however, because fire boundaries can only be located approximately. We indirectly estimate fire-size distributions without attempting to establish individual fire perimeters. The slope and intercept of the interval-area function, a power-law relationship between sample area and mean fire-free intervals for that area, provide surrogates for the moments of a fire-size distribution, given a distribution of fire- free intervals. Analogously, by deconstructing variograms that use a binary distance measure (Sorensen's index) for the similarity of the time-series of fires recorded by pairs of recorder trees, we provide estimates of modal fire size. We link both variograms and interval-area functions to fire size distributions by simulating fire size distributions on neutral landscapes with and without right- censoring to represent topographic controls on maximum fire size. From parameters of the two functions produced by simulations we can back-estimate means and variances of fire sizes on real landscapes. This scale-based modeling provides a robust alternative to empirical and heuristic methods and a means to extrapolate estimates of fire-size distributions to unsampled landscapes.

  20. Psychological sequelae of the station nightclub fire: Comparing survivors with and without physical injuries using a mixed-methods analysis.

    Directory of Open Access Journals (Sweden)

    Nhi-Ha T Trinh

    Full Text Available Surveying survivors from a large fire provides an opportunity to explore the impact of emotional trauma on psychological outcomes.This is a cross-sectional survey of survivors of The Station Fire. Primary outcomes were post-traumatic stress (Impact of Event Scale - Revised and depressive (Beck Depression Inventory symptoms. Linear regression was used to examine differences in symptom profiles between those with and without physical injuries. The free-response section of the survey was analyzed qualitatively to compare psychological sequelae of survivors with and without physical injuries.104 participants completed the study survey; 47% experienced a burn injury. There was a 42% to 72% response rate range. The mean age of respondents was 32 years, 62% were male, and 47% experienced a physical injury. No significant relationships were found between physical injury and depressive or post-traumatic stress symptom profiles. In the qualitative analysis, the emotional trauma that survivors experienced was a major, common theme regardless of physical injury. Survivors without physical injuries were more likely to experience survivor guilt, helplessness, self-blame, and bitterness. Despite the post-fire challenges described, most survivors wrote about themes of recovery and renewal.All survivors of this large fire experienced significant psychological sequelae. These findings reinforce the importance of mental health care for all survivors and suggest a need to understand factors influencing positive outcomes.

  1. Macrocharcoal analysis of a 4200 year old lake sediment profile from Northern Romania - fire regimes and climate implications

    Directory of Open Access Journals (Sweden)

    Anca GEANTĂ

    2014-11-01

    Full Text Available Macroscopic charcoal particles, magnetic susceptibility and AMS C14 dates were performed on a sediment sequence from a small subalpine lake (Buhaescu Mare, Rodnei Mts. in order to reconstruct fire regimes in the area.  Specifically we aim to distinguish between natural fire activity and human driven fires. Buhaescu Mare lake, also known as Rebra lake (0.4 ha; 1920 m a.s.l., is today surrounded by mire vegetation, Ericaceae, Carex and Pinus mugo patches further away, being situated just above the current tree line. The sedimentary profile, with a total length of 98 cm is composed of clayey silt (98-80 cm and gyttja (80-0 cm. Magnetic susceptibility was used to support the charcoal results, this parameter being expected to rise during episodes of intense fire and subsequent erosive events.The results from the charcoal record indicate periods of high charcoal activity at about 4200 cal. BP, 3000 cal. BP, 2700 cal BP, 2000 cal BP and 1350 cal BP. and point to a succession of warm/dry and cold/wet periods. The increase in charcoal particles over the last 2000 years was probably related to human impact, but this remains to be documented through the analysis of pollen and coprophilous fungi record.

  2. 火灾下钢筋混凝土框架结构的全过程分析%On whole-process analysis of reinforced concrete frame structure in fire accidents

    Institute of Scientific and Technical Information of China (English)

    王剑锋; 李永振; 朱伟平

    2012-01-01

    According to the simulation of the reinforced concrete frame structure in fire environment,the paper analyzes the change process of the temperature field in the frame structure,undertakes the whole-process analysis of the mechanical performance of the frame structure in the fire,and realizes the whole-process analysis of the fire response of the frame structure,so as to provide the theoretic reference for the fire-resistance design of the frame.%通过对钢筋混凝土框架结构火灾环境模拟,分析了框架结构内部的温度场变化过程,并对火灾下框架结构的力学性能进行了全过程分析,真正实现了框架结构火灾反应的全过程分析,为框架的抗火设计提供理论依据。

  3. Numerical Simulation of Firing Sequence of Bridge-wire EED%桥丝式电火工品发火过程的数值仿真

    Institute of Scientific and Technical Information of China (English)

    龙兵; 常新龙; 张磊; 余堰峰; 张有宏; 胡宽

    2009-01-01

    应用有限元分析软件ANSYS,建立了桥丝式电火工品的有限元仿真模型,对桥丝式电火工品的直流发火过程和电容放电发火过程进行了有限元分析,得出了两种情况下火工品的温度分布云图、径向温度分布曲线和桥丝与药剂交界面的温度变化曲线,并对仿真结果进行了分析讨论.%Using ANSYS engineering analysis software,the finite element analysis model for the bridge-wire EED was set up in this paper. The finite element analysis is carried out for firing sequence on direct current firing and capacitor discharge firing condition. Radial temperature,radial temperature distribution and temperature curve at the interface of bridge-wire and ignition powder were procured and the results were discussed.

  4. Treatment and Analysis of a Paint Chip from "Water Lilies": A Fire Damaged Monet

    Science.gov (United States)

    Miller, Sharon K. R.; Banks, Bruce A.; Tollis, Greg

    2001-01-01

    A museum fire in 1958 severely damaged a Monet 'Water Lilies' (1916-1926) painting that was on display. The surface of the painting is very dark with areas of blistering and charring. Over the years, traditional techniques have been found to be ineffective at removal of the soot and char from the surface. The painting, which is now in the care of the New York University (NYU) Conservation Center of the Institute of Fine Arts, was the subject of a study to determine if atomic oxygen treatment could remove the soot and char without damaging the fragile painting underneath. For test purposes, a small chip of paint was removed from the edge of the painting by a conservator at NYU and supplied to NASA Glenn Research Center for atomic oxygen treatment and analysis. The diffuse spectral reflectance, at three locations on the paint chip, was monitored at intervals during the atomic oxygen treatment process. Photo documentation of the chip during treatment was also performed. The color contrast was calculated from the spectral reflectance data as a function of treatment duration. Results of the testing indicated that the contrast improved as a result of the treatment, and the differentiation of colors on the surface was significantly improved. Soot and char could be removed without visibly affecting the gross surface features such as impasto areas. These results indicate the feasibility for the treatment of the 'Water Lilies' painting.

  5. Value analysis of district heating system with gas-fired peak load boiler in secondary network

    Institute of Scientific and Technical Information of China (English)

    郑雪晶; 穆振英

    2009-01-01

    In district heating(DH) system with gas-fired peak load regulating boiler in the secondary network,by prolonging run time of base load plants under rated condition,the mean energy efficiency could be increased. The fuels of the system,including coal and gas,would cause different environmental impacts. Meanwhile,the reliability of the heating networks would be changed because the peak load regulating boiler could work as a standby heat source. A model for assessment of heating system was established by value analysis to optimize this kind of system. Energy consumption,greenhouse gas emission,pollution emission and system reliability were selected as functional assessment indexes in the model. Weights of each function were determined by analytical hierarchy process (AHP) and experts consultation. Life cycle cost was used as the cost in the model. A real case as an example was discussed to obtain the optimal base load ratio. The result shows that the optimal base load ratio of the case is 0.77.

  6. Exergetic analysis of a steam power plant using coal and rice straw in a co-firing process

    Energy Technology Data Exchange (ETDEWEB)

    Restrepo, Alvaro; Miyake, Raphael Guardini; Bazzo, Edson [Federal University of Santa Catarina (UFSC), Dept. of Mechanical Engineering, Florianopolis, SC (Brazil)], e-mails: arestrep@labcet.ufsc.br, miyake@labcet.ufsc.br, ebazzo@emc.ufsc.br; Bzuneck, Marcelo [Tractebel Energia S.A., Capivari de Baixo, SC (Brazil). U.O. Usina Termeletrica Jorge Lacerda C.], e-mail: marcelob@tractebelenergia.com.br

    2010-07-01

    This paper presents an exergetic analysis concerning an existing 50 M We steam power plant, which operates with pulverized coal from Santa Catarina- Brazil. In this power plant, a co-firing rice straw is proposed, replacing up to 10% of the pulverized coal in energy basis required for the boiler. Rice straw has been widely regarded as an important source for bio-ethanol, animal feedstock and organic chemicals. The use of rice straw as energy source for electricity generation in a co-firing process with low rank coal represents a new application as well as a new challenge to overcome. Considering both scenarios, the change in the second law efficiency, exergy destruction, influence of the auxiliary equipment and the greenhouse gases emissions such as CO{sub 2} and SO{sub 2} were considered for analysis. (author)

  7. Socio-economic impact analysis: Centralia mine fire abatement alternatives. Draft report

    Energy Technology Data Exchange (ETDEWEB)

    1980-11-07

    The overall purpose of information contained in the following text is to document the likely social and economic impacts upon the Borough of Centralia through implementation of various mine fire abatement alternatives. Much of the data presented herein and utilized in preparing conclusions and recommendations have been derived from those individuals whose lives are now, or may eventually be, impacted by the underground mine fire.

  8. Sub-Scale Analysis of New Large Aircraft Pool Fire-Suppression

    Science.gov (United States)

    2016-01-01

    style dual heat flux gages positioned 90-degrees apart and around the fire perimeter recorded total and radiation heat flux. A single infrared and two...conditions could fully-develop. Four fire suppression nozzles positioned 90-degrees apart near the base and perpendicular to the fuel pan then discharged...conduction thermally coupled to the surrounding gaseous flow field. Agent spray conditions were defined as DPM flat-fan-atomizer injection types with

  9. A MUSCLE-SPINDLE MODEL FOR PRIMARY AFFERENT FIRING BASED ON A SIMULATION OF INTRAFUSAL MECHANICAL EVENTS

    NARCIS (Netherlands)

    SCHAAFSMA, A; OTTEN, E; VANWILLIGEN, JD

    1991-01-01

    1. A muscle spindle model for primary afferent firing is presented that contains two components representing a gamma-d-dependent (bag1) and gamma-s-dependent (bag2/nuclear chain) intrafusal fiber. Each of the intrafusal fibers is composed of a linear elastic element representing the sensory part and

  10. Numerical simulation of the fire smoke flow in a building corridor%建筑物条形走廊烟气运动特性研究

    Institute of Scientific and Technical Information of China (English)

    杨培培; 石必明; 穆朝民; 陆占金

    2012-01-01

    Building corridor is the necessary way in fire evacuation. Knowing the distributions of fire smoke flow in a building corridor under different conditions was helpful to evacuate and rescue. A numerical simulation of the fire smoke flow in a building corridor were presented. The distributions of gas mass fractions and gas temperature is obtained. The results showed that smoke-proof pendant wall can effectively prevent the spread of the gas in the early fire. Because of the effect of its smoke storage, it should be set in the central of the corridor. With the fire continues to expand, the effect of the smoke-proof pendant gradually abate, then mechanical smoke exhaust must be added to discharge smoke promptly. Comparing the different modes, it was concluded that the effect of the mechanical smoke exhaust at the back is better than in the front. Finally a numerical simulation combining with the real experimental was used to verify the correctness of the conclusion.%建筑物走廊是火灾时人员疏散的必经之路,了解走廊烟气的运动规律,对人员疏散与救援具有重大意义.本文对走廊内的火灾烟气进行了数值模拟,得出了不同排烟场景下走廊烟气质量分数及烟气温度的分布情况.研究表明:挡烟垂壁在火灾初期能有效地阻止烟气蔓延;由于其蓄烟作用,应该将其设置在走廊中部.但随着火势的不断扩大,挡烟垂壁效果逐渐减弱,此时必须增设机械排烟机才能及时排出烟气.对比不同机械排烟场景可知,为达到更好的排烟效果,机械排烟口应该设置在挡烟垂壁上游.最后将模拟结果与实验结果对比,验证了本文结论的正确性.

  11. 长隧道火灾烟气运动三维数值模拟%3D numerical simulation of smoke flow in long tunnel fires

    Institute of Scientific and Technical Information of China (English)

    黄亚东; 吴珂; 黄志义; 王孝红

    2011-01-01

    对某长隧道在50 MW释热率、不同风速条件下的火灾过程进行模拟,采用扩散燃烧模型对燃烧过程加以描述,分别利用k-ε模型和P-1模型计算湍流流动和辐射作用.计算结果表明,纵向风速较小时会形成烟气回流,对50 MW的隧道火灾,2 m/s的纵向通风能有效抑制烟气回流;纵向通风隧道内,烟气运动表现为径向扩散与纵向蔓延的结合;隧道通风风速越大,火源下游烟气起伏运动越剧烈.隧道发生火灾时,纵向风速应以刚好抑制烟气出现回流为宜.%A fire simulation of long tunnel under 50 MW heat release rate and different ventilation velocities was carried out. The combustion process was described by diffusion combustion model, and the k-ε model and P-1 model were used to calculate the turbulent flow and radiation. The calculations showed that, back flow of smoke will appear when the wind velocity is small, and velocity of 2 m/s can suppress the back flow when the fire is 50 MW. In tunnel with longitudinal ventilation, the smoke flow appears as the combination of radial diffusion and longitudinal diffusion. The smoke downstream the fire source fluctuates more severly as the ventilation velocity increase. During the tunnel fires, the suitable longitudinal ventilation velocity should just restrain the existence of back flow.

  12. Analysis on Remote Control of Fire Hydrant Pump%消火栓泵远程控制分析

    Institute of Scientific and Technical Information of China (English)

    鞠永健

    2014-01-01

    分析多幢建筑物合用消火栓泵房的原因和存在的问题,结合工程案例分析计算多幢建筑远程控制消火栓泵的线路压降和消防控制室启停、信号反馈等问题,对现有标准图集中的控制电路图进行修改以解决线路安全和线路压降的矛盾,并对修改后的控制电路图使用注意事项进行说明。%Control circuit diagrams given in the current standard collective drawings are modified to solve the contradictions of line safety and line drop. In addition, precautions for utilization of the modified control circuit diagrams are also given. Modification of the current standard collective drawings is based on the analysis of reasons and problems of shared fire hydrant pump rooms of multiple buildings, on the analysis and calculations via incorporating engineering cases of line drop due to remote control of fire hydrant pumps of multiple buildings , and on the analysis of such issues of start / stop and signal feedback of fire fighting control room.

  13. Chaos dynamic characteristics during mine fires

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Mine fires break out and continue in confmed scopes, studying mine fire dynamics characteristics is very usefulto prevent and control fire. The judgement index of fire chaos characteristics was introduced, chaos analysis of mine Fireprocess was described, and the reconstruction of phase space was also presented. An example of mine fire was calculated.The computations show that it is feasible to analyze mine fire dynamic characteristics with chaos theory, and indicate thatfire preoeas is a catastrophe, that is to say, the fire system changes from one state to another during mine fire

  14. Simulation and Non-Simulation Based Human Reliability Analysis Approaches

    Energy Technology Data Exchange (ETDEWEB)

    Boring, Ronald Laurids [Idaho National Lab. (INL), Idaho Falls, ID (United States); Shirley, Rachel Elizabeth [Idaho National Lab. (INL), Idaho Falls, ID (United States); Joe, Jeffrey Clark [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mandelli, Diego [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-12-01

    Part of the U.S. Department of Energy’s Light Water Reactor Sustainability (LWRS) Program, the Risk-Informed Safety Margin Characterization (RISMC) Pathway develops approaches to estimating and managing safety margins. RISMC simulations pair deterministic plant physics models with probabilistic risk models. As human interactions are an essential element of plant risk, it is necessary to integrate human actions into the RISMC risk model. In this report, we review simulation-based and non-simulation-based human reliability assessment (HRA) methods. Chapter 2 surveys non-simulation-based HRA methods. Conventional HRA methods target static Probabilistic Risk Assessments for Level 1 events. These methods would require significant modification for use in dynamic simulation of Level 2 and Level 3 events. Chapter 3 is a review of human performance models. A variety of methods and models simulate dynamic human performance; however, most of these human performance models were developed outside the risk domain and have not been used for HRA. The exception is the ADS-IDAC model, which can be thought of as a virtual operator program. This model is resource-intensive but provides a detailed model of every operator action in a given scenario, along with models of numerous factors that can influence operator performance. Finally, Chapter 4 reviews the treatment of timing of operator actions in HRA methods. This chapter is an example of one of the critical gaps between existing HRA methods and the needs of dynamic HRA. This report summarizes the foundational information needed to develop a feasible approach to modeling human interactions in the RISMC simulations.

  15. Impacts of Boreal Forest Fires and Post-Fire Succession on Energy Budgets and Climate in the Community Earth System Model

    Science.gov (United States)

    Rogers, B. M.; Randerson, J. T.; Bonan, G. B.

    2011-12-01

    Vegetation compositions of boreal forests are determined largely by recovery patterns after large-scale disturbances, the most notable of which is wildfire. Forest compositions exert large controls on regional energy and greenhouse gas budgets by affecting surface albedo, net radiation, turbulent energy fluxes, and carbon stocks. Impacts of boreal forest fires on climate are therefore products of direct fire effects, including charred surfaces and emitted aerosols and greenhouse gasses, and post-fire vegetation succession, which affects carbon and energy exchange for many decades after the initial disturbance. Climate changes are expected to be greatest at high latitudes, leading many to project increases in boreal forest fires. While numerous studies have documented the effects of post-fire landscape on energy and gas budgets in boreal forests, to date no continental analysis using a coupled model has been performed. In this study we quantified the effects of boreal forest fires and post-fire succession on regional and global climate using model experiments in the Community Earth System Model. We used 20th century climate data and MODIS vegetation continuous fields and land cover classes to identify boreal forests across North America and Eurasia. Historical fire return intervals were derived from a regression approach utilizing the Canadian and Alaskan Large Fire Databases, the Global Fire Emissions Database v3, and land cover and climate data. Succession trajectories were derived from the literature and MODIS land cover over known fire scars. Major improvements in model-data comparisons of long-term energy budgets were observed by prescribing post-fire vegetation succession. Global simulations using historical and future burn area scenarios highlight the potential impacts on climate from changing fire regimes and provide motivation for including vegetation succession in coupled simulations.

  16. Analysis and simulation of straw fuel logistics

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, Daniel [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Agricultural Engineering

    1998-12-31

    Straw is a renewable biomass that has a considerable potential to be used as fuel in rural districts. This bulky fuel is, however, produced over large areas and must be collected during a limited amount of days and taken to the storages before being ultimately transported to heating plants. Thus, a well thought-out and cost-effective harvesting and handling system is necessary to provide a satisfactory fuel at competitive costs. Moreover, high-quality non-renewable fuels are used in these operations. To be sustainable, the energy content of these fuels should not exceed the energy extracted from the straw. The objective of this study is to analyze straw as fuel in district heating plants with respect to environmental and energy aspects, and to improve the performance and reduce the costs of straw handling. Energy, exergy and emergy analyses were used to assess straw as fuel from an energy point of view. The energy analysis showed that the energy balance is 12:1 when direct and indirect energy requirements are considered. The exergy analysis demonstrated that the conversion step is ineffective, whereas the emergy analysis indicated that large amounts of energy have been used in the past to form the straw fuel (the net emergy yield ratio is 1.1). A dynamic simulation model, called SHAM (Straw HAndling Model), has also been developed to investigate handling of straw from the fields to the plant. The primary aim is to analyze the performance of various machinery chains and management strategies in order to reduce the handling costs and energy needs. The model, which is based on discrete event simulation, takes both weather and geographical conditions into account. The model has been applied to three regions in Sweden (Svaloev, Vara and Enkoeping) in order to investigate the prerequisites for straw harvest at these locations. The simulations showed that straw has the best chances to become a competitive fuel in south Sweden. It was also demonstrated that costs can be

  17. Developing a probabilistic fire risk model and its application to fire danger systems

    Science.gov (United States)

    Penman, T.; Bradstock, R.; Caccamo, G.; Price, O.

    2012-04-01

    Wildfires can result in significant economic losses where they encounter human assets. Management agencies have large budgets devoted to both prevention and suppression of fires, but little is known about the extent to which they alter the probability of asset loss. Prediction of the risk of asset loss as a result of wildfire requires an understanding of a number of complex processes from ignition, fire growth and impact on assets. These processes need to account for the additive or multiplicative effects of management, weather and the natural environment. Traditional analytical methods can only examine only a small subset of these. Bayesian Belief Networks (BBNs) provide a methodology to examine complex environmental problems. Outcomes of a BBN are represented as likelihoods, which can then form the basis for risk analysis and management. Here we combine a range of data sources, including simulation models, empirical statistical analyses and expert opinion to form a fire management BBN. Various management actions have been incorporated into the model including landscape and interface prescribed burning, initial attack and fire suppression. Performance of the model has been tested against fire history datasets with strong correlations being found. Adapting the BBN presented here we are capable of developing a spatial and temporal fire danger rating system. Currently Australian fire danger rating systems are based on the weather. Our model accounts for existing fires, as well as the risk of new ignitions combined with probabilistic weather forecasts to identify those areas which are most at risk of asset loss. Fire growth is modelled with consideration given to management prevention efforts, as well as suppression resources that are available in each geographic locality. At a 10km resolution the model will provide a probability of asset loss which represents a significant step forward in the level of information that can be provided to the general public.

  18. Evaluating post-fire forest resilience using GIS and multi-criteria analysis: an example from Cape Sounion National Park, Greece.

    Science.gov (United States)

    Arianoutsou, Margarita; Koukoulas, Sotirios; Kazanis, Dimitrios

    2011-03-01

    Forest fires are one of the major causes of ecological disturbance in the mediterranean climate ecosystems of the world. Despite the fact that a lot of resources have been invested in fire prevention and suppression, the number of fires occurring in the Mediterranean Basin in the recent decades has continued to markedly increase. The understanding of the relationship between landscape and fire lies, among others, in the identification of the system's post-fire resilience. In our study, ecological and landscape data are integrated with decision-support techniques in a Geographic Information Systems (GIS) framework to evaluate the risk of losing post-fire resilience in Pinus halepensis forests, using Cape Sounion National Park, Central Greece, as a pilot case. The multi-criteria decision support approach has been used to synthesize both bio-indicators (woody cover, pine density, legume cover and relative species richness and annual colonizers) and geo-indicators (fire history, parent material, and slope inclination) in order to rank the landscape components. Judgments related to the significance of each factor were incorporated within the weights coefficients and then integrated into the multicriteria rule to map the risk index. Sensitivity analysis was very critical for assessing the contribution of each factor and the sensitivity to subjective weight judgments to the final output. The results of this study include a final ranking map of the risk of losing resilience, which is very useful in identifying the "risk hotspots", where post-fire management measures should be applied in priority.

  19. US Fire Administration Fire Statistics

    Data.gov (United States)

    Department of Homeland Security — The U.S. Fire Administration collects data from a variety of sources to provide information and analyses on the status and scope of the fire problem in the United...

  20. Analysis and simulation of XPM intensity modulation

    Institute of Scientific and Technical Information of China (English)

    Jing Huang; Jianquan Yao

    2005-01-01

    Based on the split-step Fourier method and small signal analysis, an improved analytical solution which describes the cross-phase modulation (XPM) intensity is derived. It can suppress the spurious XPM intensity modulation efficiently in the whole transmission fiber. Thus it is more coincidence with the practical result. Furthermore, it is convenient, because it is independent of channel separation and the dispersion and nonlinear effects interact through the XPM intensity. A criterion of select the step size is described as the derived XPM intensity modulation being taken into account. It is non-uniform distribution method, the simulation accuracy is improved when the step size is determined by the improved XPM intensity.

  1. Remote sensing analysis of vegetation recovery following short-interval fires in Southern California shrublands.

    Science.gov (United States)

    Meng, Ran; Dennison, Philip E; D'Antonio, Carla M; Moritz, Max A

    2014-01-01

    Increased fire frequency has been shown to promote alien plant invasions in the western United States, resulting in persistent vegetation type change. Short interval fires are widely considered to be detrimental to reestablishment of shrub species in southern California chaparral, facilitating the invasion of exotic annuals and producing "type conversion". However, supporting evidence for type conversion has largely been at local, site scales and over short post-fire time scales. Type conversion has not been shown to be persistent or widespread in chaparral, and past range improvement studies present evidence that chaparral type conversion may be difficult and a relatively rare phenomenon across the landscape. With the aid of remote sensing data covering coastal southern California and a historical wildfire dataset, the effects of short interval fires (vegetation cover was found in some lower elevation areas that were burned twice in short interval fires, where non-sprouting species are more common. However, extensive type conversion of chaparral to grassland was not evident in this study. Most variables, with the exception of elevation, were moderately or poorly correlated with differences in vegetation recovery.

  2. ADAMS Based Dynamic Simulation of Assault Gun Firing%基于ADAMS的某突击炮发射动力学仿真

    Institute of Scientific and Technical Information of China (English)

    申江森; 高跃飞; 徐凤军

    2015-01-01

    在对突击炮结构特点研究的基础上,根据设计参数要求,应用 ADAMS进行了突击炮虚拟样机模型建立和动力学相应计算。轮胎选用U A模型,基于脚本程序控制的方法,对突击炮在方向角0°、射角30°工况下的动力学响应进行了仿真分析,得到了满意的结果。%In order to understand the dynamic behavior of assault gun during gun fire ,a virtual prototype of the assault gun was set up using the ADAMS software package ,and its dynamic responses were analyzed .In the prototype ,UA model was used to tire ,and the script with simulation method was used to analyze the response of the assault gun during direction angle at zero degree and angle of fire at 30 degree .Finally ,the dynamic responses of this assault gun were simulated using the prototype .

  3. A study of the evolution of rust on Mo-Cu-bearing fire-resistant steel submitted to simulated atmospheric corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Hao Long [State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Wencui Road 62, Shenyang 110016 (China); Zhang Sixun [College of Material and Metallurgy, Northeastern University, Wenhua Road 3, Shenyang 110004 (China); Technical Centre of Laiwu Steel Group, Ltd., Changsheng Road 23, Laiwu 271104 (China); Dong Junhua, E-mail: jhdong@imr.ac.cn [State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Wencui Road 62, Shenyang 110016 (China); Ke Wei [State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Wencui Road 62, Shenyang 110016 (China)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer The rusting evolution of a Mo-Cu-bearing fire-resistant steel in a simulated industrial atmosphere was investigated. Black-Right-Pointing-Pointer The rusting evolution of the steel is related to the rust composition, structure, and electrochemical characteristics. Black-Right-Pointing-Pointer Increased content of {alpha}-FeOOH and decreased {gamma}-FeOOH and Fe{sub 3}O{sub 4} indicate the enhanced resistance of the rust. Black-Right-Pointing-Pointer Mo and Cu are involved in the formation of molybdate and Cu(I)-bearing compounds in the rust. - Abstract: The corrosion evolution of a Mo-Cu-bearing fire-resistant steel in a simulated industrial atmosphere was investigated by corrosion weight gain, XRD, EPMA, XPS, and polarization curves. The results indicate that the corrosion kinetics is closely related to the rust composition and electrochemical properties. As the corrosion proceeds, the relative content of {gamma}-FeOOH and Fe{sub 3}O{sub 4} decreases and {alpha}-FeOOH increases, and the rust layer becomes compact and adherent to steel substrate. Molybdenum and copper enrich in the inner rust layer, especially at the bottom of the corrosion nest, forming non-soluble molybdate and Cu(I)-bearing compounds responsible for enhanced corrosion resistance of the rust layer.

  4. Advanced Modeling, Simulation and Analysis (AMSA) Capability Roadmap Progress Review

    Science.gov (United States)

    Antonsson, Erik; Gombosi, Tamas

    2005-01-01

    Contents include the following: NASA capability roadmap activity. Advanced modeling, simulation, and analysis overview. Scientific modeling and simulation. Operations modeling. Multi-special sensing (UV-gamma). System integration. M and S Environments and Infrastructure.

  5. Laboratory simulation of temperature changes by insolation and fire and their influence on physical properties of travertines

    Directory of Open Access Journals (Sweden)

    Zuzana Kompaníková

    2012-06-01

    Full Text Available The influence of insolation and fire represents important factor for study of historical object destruction. The results have shown that temperature changes by insolation (60°C and fire (200, 400, 600, and 800°C significantly contributed to the change of physical properties of Slovak travertine from Spišské Podhradie and Ludrová. Research was oriented not only on a visual change of rocks (colour change, brightness and surface roughness, but also on the quantitative and qualitative analyses of mineral composition, connected with structural changes as well as study of selected physical properties. The micropetrographic study indicated that increasing of temperature was followed by expand of fractures as reflected even change of true and specific bulk density. Significant increase of microcracks was determined at 600°C by optical microscopy. The macroscopic observation of microcracks was visible at 800°C subsequently followed by destruction of samples. By spectrophotometry was visible colour change by increasing of temperature. The brightness of travertine samples was decreasing till 600°C, but after 600°C it became markedly increasing. With increasing of temperature travertine surface samples had also change from a few hundred nanometres to several microns. The investigation of thermal decay by insolation and fire may lead to an improved assessment of natural building stones that have been used as building and decorative stone on ancient monument.

  6. Hunting for origins of migraine pain: cluster analysis of spontaneous and capsaicin-induced firing in meningeal trigeminal nerve fibers

    Directory of Open Access Journals (Sweden)

    Andrei eZakharov

    2015-07-01

    Full Text Available Trigeminal nerves in meninges are implicated in generation of nociceptive firing underlying migraine pain. However, the neurochemical mechanisms of nociceptive firing in meningeal trigeminal nerves are little understood. In this study, using suction electrode recordings from peripheral branches of the trigeminal nerve in isolated rat meninges, we analyzed spontaneous and capsaicin-induced orthodromic spiking activity. In control, biphasic single spikes with variable amplitude and shapes were observed. Application of the TRPV1 agonist capsaicin to meninges dramatically increased firing whereas the amplitudes and shapes of spikes remained essentially unchanged. This effect was antagonized by the specific TRPV1 antagonist capsazepine. Using the clustering approach, several groups of uniform spikes (clusters were identified. The clustering approach combined with capsaicin application allowed us to detect and to distinguish ‘responder’ (65% from ‘non-responder’ clusters (35%. Notably, responders fired spikes at frequencies exceeding 10 Hz, high enough to provide postsynaptic temporal summation of excitation at spinal cord level. Almost all spikes were suppressed by TTX suggesting an involvement of the TTX-sensitive sodium channels in nociceptive signaling at the peripheral branches of trigeminal neurons. Our analysis also identified transient (desensitizing and long-lasting (slowly desensitizing, responses to the continuous application of capsaicin. Thus, the persistent activation of nociceptors in capsaicin-sensitive nerve fibers shown here may be involved in trigeminal pain signaling and plasticity along with the release of migraine-related neuropeptides from TRPV1 positive neurons. Furthermore, cluster analysis could be widely used to characterize the temporal and neurochemical profiles of other pain transducers likely implicated in migraine.

  7. Quantitative analysis of alkaloidal constituents in imported fire ants by gas chromatography.

    Science.gov (United States)

    Yu, Yu-Ting; Wei, Hong-Yi; Fadamiro, Henry Y; Chen, Li

    2014-06-25

    A method based on silica gel chromatography and GC-MS/GC-FID analyses was developed for the quantitation of alkaloidal compounds in imported fire ants, Solenopsis richteri, S. invicta, and their hybrid found in the southern United States. The cis and trans alkaloids from fire ant body extracts were successfully separated by silica gel chromatography, identified by GC-MS, and quantitated by GC-FID. Piperideine compounds were eluted together with the cis and trans piperidines, but were well-resolved on a nonpolar GC column. Eight pairs of piperidine isomers and 12 piperideines were quantitated. The ratios of trans alkaloids to corresponding cis isomers ranged from 87 to 378:1 in S. invicta and were significantly higher than in S. richteri and hybrid ants. The results were discussed in relation to the evolution of fire ant venom alkaloids and their role as host location cues for parasitic Pseudacteon phorid flies.

  8. Augmenting health care failure modes and effects analysis with simulation

    DEFF Research Database (Denmark)

    Staub-Nielsen, Ditte Emilie; Dieckmann, Peter; Mohr, Marlene;

    2014-01-01

    This study explores whether simulation plays a role in health care failure mode and effects analysis (HFMEA); it does this by evaluating whether additional data are found when a traditional HFMEA is augmented with simulation. Two multidisciplinary teams identified vulnerabilities in a process...... for deeper analysis. The study indicates that simulation has a role in HFMEA. Both ways of using simulation seemed feasible, and our results are not conclusive in selecting one over the other....

  9. Fire Management Problem Analysis of Key Unit of Fire Safety%消防安全重点单位消防管理问题分析

    Institute of Scientific and Technical Information of China (English)

    王慧萍

    2013-01-01

    消防安全重点单位一般都是对单位当地或者是国民经济发展有着较大的促进作用,它们也是消防部门的工作需要予以较多关注的对象。本文主要从这些重点单位的消防安全着手,简要的分析这些单位在消防安全方面所做的工作,并指出其存在的缺陷和不足,及时的为其安全管理部门提供相应的解决对策,帮助这些消防安全重点单位综合有效的做好消防的管理和监督工作。%Key unit of fire safety is usually important for the promotion of the local national economic development, so more attention from the fire department should be paid to them. This article mainly starts from the fire safety of these key units, briefly analyzes the fire safety work of these units and points out the defects and deficiencies, offering countermeasures for the safety management department to help these key units of fire safety to go a good job in fire safety management and monitoring comprehensively and effectively.

  10. Wildland Arson as Clandestine Resource Management: A Space-Time Permutation Analysis and Classification of Informal Fire Management Regimes in Georgia, USA

    Science.gov (United States)

    Coughlan, Michael R.

    2016-05-01

    Forest managers are increasingly recognizing the value of disturbance-based land management techniques such as prescribed burning. Unauthorized, "arson" fires are common in the southeastern United States where a legacy of agrarian cultural heritage persists amidst an increasingly forest-dominated landscape. This paper reexamines unauthorized fire-setting in the state of Georgia, USA from a historical ecology perspective that aims to contribute to historically informed, disturbance-based land management. A space-time permutation analysis is employed to discriminate systematic, management-oriented unauthorized fires from more arbitrary or socially deviant fire-setting behaviors. This paper argues that statistically significant space-time clusters of unauthorized fire occurrence represent informal management regimes linked to the legacy of traditional land management practices. Recent scholarship has pointed out that traditional management has actively promoted sustainable resource use and, in some cases, enhanced biodiversity often through the use of fire. Despite broad-scale displacement of traditional management during the 20th century, informal management practices may locally circumvent more formal and regionally dominant management regimes. Space-time permutation analysis identified 29 statistically significant fire regimes for the state of Georgia. The identified regimes are classified by region and land cover type and their implications for historically informed disturbance-based resource management are discussed.

  11. Wildland Arson as Clandestine Resource Management: A Space-Time Permutation Analysis and Classification of Informal Fire Management Regimes in Georgia, USA.

    Science.gov (United States)

    Coughlan, Michael R

    2016-05-01

    Forest managers are increasingly recognizing the value of disturbance-based land management techniques such as prescribed burning. Unauthorized, "arson" fires are common in the southeastern United States where a legacy of agrarian cultural heritage persists amidst an increasingly forest-dominated landscape. This paper reexamines unauthorized fire-setting in the state of Georgia, USA from a historical ecology perspective that aims to contribute to historically informed, disturbance-based land management. A space-time permutation analysis is employed to discriminate systematic, management-oriented unauthorized fires from more arbitrary or socially deviant fire-setting behaviors. This paper argues that statistically significant space-time clusters of unauthorized fire occurrence represent informal management regimes linked to the legacy of traditional land management practices. Recent scholarship has pointed out that traditional management has actively promoted sustainable resource use and, in some cases, enhanced biodiversity often through the use of fire. Despite broad-scale displacement of traditional management during the 20th century, informal management practices may locally circumvent more formal and regionally dominant management regimes. Space-time permutation analysis identified 29 statistically significant fire regimes for the state of Georgia. The identified regimes are classified by region and land cover type and their implications for historically informed disturbance-based resource management are discussed.

  12. The tariff for fire and theft car insurance: analysis with a Cox model

    Directory of Open Access Journals (Sweden)

    Bruno Scarpa

    2013-05-01

    Full Text Available In this paper we analyze the problem of identification of a tariff for a Fire & Theft Car policy for Insurance Companies. Usually companies obtain this tariff by empirical estimate of the pure rate by evaluating the impact of some personalization variables. In this paper we propose the usage of a semi-parametric Cox model, where the response variable is not the waiting time until an event, but the degree of damage because of theft or fire of a car. The proposed model allows to easily tackle typical problems in data available to the companies, like the presence of franchises, which are treated as censored data.

  13. STUDY ON FOREST FIRE DANGER MODEL WITHREMOTE SENSING BASED ON GIS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    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 dsnger prediction model, in which relative importance of each fire factor is taken into account, is built based on GIS.

  14. Simulation of crowd evacuation in fire based on agent behavior%火灾中基于个体行为的人群疏散仿真

    Institute of Scientific and Technical Information of China (English)

    陆卓谟; 秦文虎

    2011-01-01

    为了指导火灾中的人群疏散,研究了一种新的人群疏散模型用于提高人群疏散仿真的真实性.通过分析个体对火灾警报的不同响应时间,个体在疏散过程中采取的不同运动速度,个体间的组运动方式,个体的出口选择等因素对人群疏散的影响,建立了个体行为特征与元胞自动机相结合的人群疏散模型.该模型包括个体对火灾警报响应模型、个体逃生速度模型、组运动模型和出口选择模型.仿真分析表明:火灾中不同的个体行为对建筑物内人群疏散的总体时间有较大影响;人群疏散仿真中引入个体的反应时间和组运动方式能使人群疏散仿真更加真实.%For guiding the crowd evacuation in fire, a new crowd evacuation model based on agent's behavior which can improve the realism of crowd evacuation is proposed. Through analyzing the influences of many factors on the evacuation process, including agent's different reaction time when encountering the fire alarm, different moving velocities in the process of evacuation, application of group movement and the selection of exits, a model combining the characteristics of agent behaviors and cellular automata is established. The model includes the agent's response of fire alarm model, the agent's evacuation speed model, the group movement model and exit selection model. The simulation results show that different agent behavior in fire remarkably influence total time of crowd evacuation in building. Crowd evacuation simulation integrating agent's reaction time and group movement can improve the realism greatly.

  15. Diagnostics and Control of Natural Gas-Fired furnaces via Flame Image Analysis using Machine Vision & Artificial Intelligence Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Shahla Keyvan

    2005-12-01

    A new approach for the detection of real-time properties of flames is used in this project to develop improved diagnostics and controls for natural gas fired furnaces. The system utilizes video images along with advanced image analysis and artificial intelligence techniques to provide virtual sensors in a stand-alone expert shell environment. One of the sensors is a flame sensor encompassing a flame detector and a flame analyzer to provide combustion status. The flame detector can identify any burner that has not fired in a multi-burner furnace. Another sensor is a 3-D temperature profiler. One important aspect of combustion control is product quality. The 3-D temperature profiler of this on-line system is intended to provide a tool for a better temperature control in a furnace to improve product quality. In summary, this on-line diagnostic and control system offers great potential for improving furnace thermal efficiency, lowering NOx and carbon monoxide emissions, and improving product quality. The system is applicable in natural gas-fired furnaces in the glass industry and reheating furnaces used in steel and forging industries.

  16. Socio-geographic analysis of wild land fires: causes of the 2006's wildfires in Galicia (Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Balsa-Barreiro, J.; Hermosilla, T.

    2013-07-01

    Aim of study: To propose a methodology to establish motivations underlying wildland fire episodes by analyzing both the socioeconomics of the affected territory and the geographical distribution of the wildfire. Area of study: The wildfires occurred during 2006 in Galicia, in the NW of Spain, were analyzed and compared regard to the previous years. Material and methods: The proposed methodology in this study is divided into four steps: (a) definition of the forest context, (b) fire episode and socioeconomic data collection, (c) geospatial representation through map production, and (d) joint analysis and data interpretation. A combined analysis of the spatial and temporal coincidence of wildfire and the socioeconomic activities is performed. Main results: A combined analysis of the spatial and temporal coincidence of wildfire dynamics and the socioeconomic activities allow us to assess and to interpret wildfire causes and motivations of socioeconomic groups. In our area study, a broad analysis indicates that wildfire recurrence within this region is related to an accelerated rural flight process which exacerbates the conflict between rural and urban models. Research highlights: The socio-geographical analysis of a territory's wildfire dynamics enables us to establish possible causes and motivations of their origins. Providing the specific contextual and socioeconomic information, this methodology has potential applicability across varied study locations. (Author)

  17. 基于Rothermel模型的森林火灾模拟算法的改进%Improvement of the Forest Fires Simulation Algorithm Based on the Rothermel Model

    Institute of Scientific and Technical Information of China (English)

    苗双喜; 黄杨; 张波; 孙恒宇

    2012-01-01

    我国是一个森林火灾多发的国家,森林火灾不仅破坏森林生态系统、造成林木资源损失,还会威胁到人民的生命财产安全.因此如何快速精确地模拟森林火灾的蔓延过程对于防灾减灾有重大的意义和作用,本文在深入对比了国内外各种森林火灾蔓延模型的基础上,选择了抽象程度较高、顾及因素全面的Rothermel火灾蔓延模型作为本文的应用模型,在模型的应用中改正了森林火灾范围割的缺陷,优化了多着火点同时蔓延时火灾边界计算方法,最终实现森林火灾模拟的功能,满足了森林火灾蔓延模拟实时高效的要求,为管理部门提供可靠的决策支持.%Forest fire has been happened frequently in China. Forest fires not only destroy the forest ecosystem, resulting in the loss of forest resources, but also are a threat to the safety of life and property of the people. Therefore, how to quickly and accurately simulate the spread of forest fires is of great significance and role in disaster prevention and mitigation. Comparing all kinds of forest fire spread models at home and abroad, this paper selected Rothermel fire spread model as the application model, which have advantages of a high degree of abstraction and taking into account factors comprehensive. During the application of the model, it corrected the forest fire scope fragmented defect,Optimized fire boundary calculation method when the begin fire points catch fire at the same time. In this way, it can achieve the fire simulation function, meet the forest fire spread simulation of real-time and efficient requirements and provide reliable decision support for the management department.

  18. Analysis of Moisture Evaporation from Underwear Designed for Fire-Fighters

    Directory of Open Access Journals (Sweden)

    Elena Onofrei

    2015-03-01

    Full Text Available In this study we analysed the effect of moisture on the thermal protective performance of fire-fighter clothing in case of routine fire-fighting conditions. In the first stage of this research we investigated simultaneous heat and moisture transfer through a single-layer fabric, used as underwear for fire-fighters, at different moisture conditions. In the second stage of the study, the underwear in dry and wet state was tested together with protective clothing systems for fire-fighter consisting of three or four layers. It was found that during the evaporation of the moisture, a temperature plateau appeared during which temperatures hardly rose. The energy consumption used for the phase change of moisture located in the assembly dominated the heat transfer process as long as there was moisture present. As soon as all water had evaporated, the temperatures approached the temperatures measured for dry samples. The moisture within the clothing assembly did not lead to increased temperatures compared with the measurements with dry samples. This research has confirmed that moisture can positively affect the thermal protection of a clothing system.

  19. Factor contribution to fire occurrence, size, and burn probability in a subtropical coniferous forest in East China

    Science.gov (United States)

    Guo, Zhixing; Li, Yijia

    2017-01-01

    The contribution of factors including fuel type, fire-weather conditions, topography and human activity to fire regime attributes (e.g. fire occurrence, size distribution and severity) has been intensively discussed. The relative importance of those factors in explaining the burn probability (BP), which is critical in terms of fire risk management, has been insufficiently addressed. Focusing on a subtropical coniferous forest with strong human disturbance in East China, our main objective was to evaluate and compare the relative importance of fuel composition, topography, and human activity for fire occurrence, size and BP. Local BP distribution was derived with stochastic fire simulation approach using detailed historical fire data (1990–2010) and forest-resource survey results, based on which our factor contribution analysis was carried out. Our results indicated that fuel composition had the greatest relative importance in explaining fire occurrence and size, but human activity explained most of the variance in BP. This implies that the influence of human activity is amplified through the process of overlapping repeated ignition and spreading events. This result emphasizes the status of strong human disturbance in local fire processes. It further confirms the need for a holistic perspective on factor contribution to fire likelihood, rather than focusing on individual fire regime attributes, for the purpose of fire risk management. PMID:28207837

  20. How fire history, fire suppression practices and climate change affect wildfire regimes in Mediterranean landscapes.

    Directory of Open Access Journals (Sweden)

    Lluís Brotons

    Full Text Available Available data show that future changes in global change drivers may lead to an increasing impact of fires on terrestrial ecosystems worldwide. Yet, fire regime changes in highly humanised fire-prone regions are difficult to predict because fire effects may be heavily mediated by human activities We investigated the role of fire suppression strategies in synergy with climate change on the resulting fire regimes in Catalonia (north-eastern Spain. We used a spatially-explicit fire-succession model at the landscape level to test whether the use of different firefighting opportunities related to observed reductions in fire spread rates and effective fire sizes, and hence changes in the fire regime. We calibrated this model with data from a period with weak firefighting and later assess the potential for suppression strategies to modify fire regimes expected under different levels of climate change. When comparing simulations with observed fire statistics from an eleven-year period with firefighting strategies in place, our results showed that, at least in two of the three sub-regions analysed, the observed fire regime could not be reproduced unless taking into account the effects of fire suppression. Fire regime descriptors were highly dependent on climate change scenarios, with a general trend, under baseline scenarios without fire suppression, to large-scale increases in area burnt. Fire suppression strategies had a strong capacity to compensate for climate change effects. However, strong active fire suppression was necessary to accomplish such compensation, while more opportunistic fire suppression strategies derived from recent fire history only had a variable, but generally weak, potential for compensation of enhanced fire impacts under climate change. The concept of fire regime in the Mediterranean is probably better interpreted as a highly dynamic process in which the main determinants of fire are rapidly modified by changes in landscape

  1. Numerical Modelling by FLAC on Coal Fires in North China

    Science.gov (United States)

    Gusat, D.; Drebenstedt, C.

    2009-04-01

    coal mine with the backfill. A smaller fires can also be handled by taking out burning coal by bulldozing techniques described above are applicable to small fires, but they do not work well in extinction of large coal fires. References [1] http://www.coalfire.caf.dlr.de [2] Schalke, H.J.W.G.; Rosema, A.; Van Genderen, J.L. (1993): Environmental monitoring of coal fires in North China. Project Identification Mission Report. Report Remote Sensing Programme Board, Derft, the Netherlands. [3] Zhang, X.; Kroonenberg, S. B.; De Boer, C. B. (2004): Dating of coal fires in Xinjiang, north-west China. Terra Nova. Band 16, No 2, S. 68-74. DOI: 10.1111/j.1365-3121.2004.00532.x [4] Deng Jun, Hou Shuang, Li Huirong, e.t.c (2006): Oxidation Mechanism at Initial Stage of a Simulated Coal Molecule with -CH2O-[J]. Journal of Changchun University of Science and Technology, 29(2), P. 84-87. [5] Deng, Jun (2008): Presentation. Chinese Researches and Practical Experiences on Controlling Underground Coal Fires. The 2nd Australia-China Symposium on Science, Technology and Education. 15-18 October 2008, Courtyard Marriott, Surfers Paradise Beach, Gold Coast, Queensland, Australia. [6] Itasca (2003): FLAC, Fast Lagrangian Analysis of Continua. Itasca Consultants Group, Inc., Minneapolis.

  2. Post-fire overland flow generation and inter-rill erosion under simulated rainfall in two eucalypt stands in north-central Portugal.

    Science.gov (United States)

    Malvar, M C; Prats, S A; Nunes, J P; Keizer, J J

    2011-02-01

    The aim of this study was to improve the existing knowledge of the runoff and inter-rill erosion response of forest stands following wildfire, focusing on commercial eucalypt plantations and employing field rainfall simulation experiments (RSE's). Repeated RSE's were carried out in two adjacent but contrasting eucalypt stands on steep hill slopes in north-central Portugal that suffered a moderate severity fire in July 2005. This was done at six occasions ranging from 3 to 24 months after the fire and using a paired-plot experimental design that comprised two pairs of RSE's at each site and occasion. Of the 46 RSE's: (i) 24 and 22 RSE's involved application rates of 45-50 and 80-85 mm h(-1), respectively; (ii) 22 took place in a stand that had been ploughed in down slope direction several years before the wildfire and 24 in an unploughed stand. The results showed a clear tendency for extreme-intensity RSE's to produce higher runoff amounts and greater soil and organic matter losses than the simultaneous high-intensity RSE's on the neighbouring plots. However, there existed marked exceptions, both in space (for one of the plot pairs) and time (under intermediate soil water repellency conditions). Also, overland flow generation and erosion varied significantly between the various field campaigns. This temporal pattern markedly differed from a straightforward decline with time-after-fire and rather suggested a seasonal component, reflecting broad variations in topsoil water repellency. The ploughed site produced less runoff and erosion than the unploughed site, contrary to what would be expected if the down slope ploughing had occurred after the wildfire instead of several years before it. Finally, sediment losses at both study sites were noticeably lower than those reported by other studies involving repeat RSE's, i.e. in Australia and western Spain. This possibly reflected a history of intensive land use in the study region, including in more recent times after the

  3. Wild Fire Risk Map in the Eastern Steppe of Mongolia Using Spatial Multi-Criteria Analysis

    Science.gov (United States)

    Nasanbat, Elbegjargal; Lkhamjav, Ochirkhuyag

    2016-06-01

    Grassland fire is a cause of major disturbance to ecosystems and economies throughout the world. This paper investigated to identify risk zone of wildfire distributions on the Eastern Steppe of Mongolia. The study selected variables for wildfire risk assessment using a combination of data collection, including Social Economic, Climate, Geographic Information Systems, Remotely sensed imagery, and statistical yearbook information. Moreover, an evaluation of the result is used field validation data and assessment. The data evaluation resulted divided by main three group factors Environmental, Social Economic factor, Climate factor and Fire information factor into eleven input variables, which were classified into five categories by risk levels important criteria and ranks. All of the explanatory variables were integrated into spatial a model and used to estimate the wildfire risk index. Within the index, five categories were created, based on spatial statistics, to adequately assess respective fire risk: very high risk, high risk, moderate risk, low and very low. Approximately more than half, 68 percent of the study area was predicted accuracy to good within the very high, high risk and moderate risk zones. The percentages of actual fires in each fire risk zone were as follows: very high risk, 42 percent; high risk, 26 percent; moderate risk, 13 percent; low risk, 8 percent; and very low risk, 11 percent. The main overall accuracy to correct prediction from the model was 62 percent. The model and results could be support in spatial decision making support system processes and in preventative wildfire management strategies. Also it could be help to improve ecological and biodiversity conservation management.

  4. Numerical Simulation of Muzzle Flow Field for Super-high Firing-rate Series Launched Weapon%超高射频武器串联发射膛口流场数值模拟

    Institute of Scientific and Technical Information of China (English)

    张学伟; 李强; 刘武; 张正涛

    2016-01-01

    A study is made of the muzzle flow field and the influence on the projectile flying of the su-per-high firing-rate series launched weapon based on the ALE equation and chimera grids technology, in combination with dynamic grid method. The result clearly reveals that complex muzzle flow field structure of complicated gunpowder gas was formed in the process of the high firing-rate. In addition, under the same explosive charge,on the high firing-rate,the acceleration of the following projectile is far less than that of the first one. The following projectile outside the barrel,the gunpowder gas before the projectile expansion formed a low pressure area,while the pressure after the projectile is higher than the first,so that acceleration for the following projectile is greater than that for the first projectile. The simulation results provide some theoretical basis for the study of the rapid-fire strong coupling launch projectile force analysis.%为了研究超高射频武器高频连发时膛口流场形成机理和对弹丸飞行的影响,基于 ALE方程和嵌入网格技术,结合动网格方法进行数值仿真分析。数值结果清晰地揭示了高频连发时火药气体相互叠加形成的复杂流场的结构。在相同装药量下,高频连发时后续弹丸膛内加速度远小于首发弹丸;后续弹丸出膛口后,弹前火药燃气膨胀形成低压区,而弹后压力高于首发弹丸弹后压力,使其加速度大于首发弹丸。仿真结果为研究超高射频武器高频连发时弹丸受力分析提供一些理论依据。

  5. The Difficulty Getting High Escape Fractions of Ionizing Photons from High-redshift Galaxies: a View from the FIRE Cosmological Simulations

    CERN Document Server

    Ma, Xiangcheng; Hopkins, Philip F; Faucher-Giguere, Claude-Andre; Quataert, Eliot; Keres, Dusan; Murray, Norman

    2015-01-01

    We present a series of high-resolution (20-2000 Msun, 0.1-4 pc) cosmological zoom-in simulations at z~6 from the Feedback In Realistic Environment (FIRE) project. These simulations cover halo masses 10^9-10^11 Msun and rest-frame ultraviolet magnitude Muv = -9 to -19. These simulations include explicit models of the multi-phase ISM, star formation, and stellar feedback, which produce reasonable galaxy properties at z = 0-6. We post-process the snapshots with a radiative transfer code to evaluate the escape fraction (fesc) of hydrogen ionizing photons. We find that the instantaneous fesc has large time variability (0.01%-20%), while the time-averaged fesc over long time-scales generally remains ~5%, considerably lower than the estimate in many reionization models. We find no strong dependence of fesc on galaxy mass or redshift. In our simulations, the intrinsic ionizing photon budgets are dominated by stellar populations younger than 3 Myr, which tend to be buried in dense birth clouds. The escaping photons mo...

  6. High temperature erosion wear of flame and plasma-sprayed nickel-chromium coatings under simulated coal-fired boiler atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Hidalgo, V.H.; Varela, J.B.; Menendez, A.C.; Martinez, S.P. [Universidad de Oviedo, Gijon (Spain). Departamento Energia

    2001-02-01

    Erosive high temperature wear of heat exchanger tubes and other structural materials in coal-fired boilers are recognised as being the main cause of downtime at power generation plants. This study concerns the behaviour of plasma and flame sprayed modified nickel-chromium alloy (with small aluminium and titanium additions) subjected to the action of simulated post-combustion gases from a coal-fired boiler combustor. The study first evaluates the effects of thermal exposure at high temperature on the adherence between the substrate (austenitic stainless steel) and coatings. Then, the oxidation rates of these coatings in atmospheres with 3-3.5% of free oxygen at 500 and 800{degree}C (773 and 1073 K) were evaluated. The low velocity corrosion-erosion behaviour produced by the impact of fly ashes in the gas stream at high temperatures (773 and 1073 K) was also evaluated under impact angles of 30 and 90{degree}C. Finally, the eroded surfaces were analysed using scanning electron microscopy to characterise the ash embedment phenomena and the operating erosive micromechanisms. 24 refs., 13 figs., 9 tabs.

  7. Obtaining a Pragmatic Representation of Fire Disturbance in Dynamic Vegetation Models by Assimilating Earth Observation Data

    Science.gov (United States)

    Kantzas, Euripides; Quegan, Shaun

    2015-04-01

    Fire constitutes a violent and unpredictable pathway of carbon from the terrestrial biosphere into the atmosphere. Despite fire emissions being in many biomes of similar magnitude to that of Net Ecosystem Exchange, even the most complex Dynamic Vegetation Models (DVMs) embedded in IPCC General Circulation Models poorly represent fire behavior and dynamics, a fact which still remains understated. As DVMs operate on a deterministic, grid cell-by-grid cell basis they are unable to describe a host of important fire characteristics such as its propagation, magnitude of area burned and stochastic nature. Here we address these issues by describing a model-independent methodology which assimilates Earth Observation (EO) data by employing image analysis techniques and algorithms to offer a realistic fire disturbance regime in a DVM. This novel approach, with minimum model restructuring, manages to retain the Fire Return Interval produced by the model whilst assigning pragmatic characteristics to its fire outputs thus allowing realistic simulations of fire-related processes such as carbon injection into the atmosphere and permafrost degradation. We focus our simulations in the Arctic and specifically Canada and Russia and we offer a snippet of how this approach permits models to engage in post-fire dynamics hitherto absent from any other model regardless of complexity.

  8. Response of fire detectors to different smokes

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerkman, J.; Keski-Rahkonen, O. [VTT Building Technology, Espoo (Finland). Building Physics, Building Services and Fire Technology

    1997-12-31

    The purpose of this work is to characterize the behavior of fire alarm systems based on smoke detectors on smoldering fires especially cable fires in nuclear power plants (NPP). Full-scale fire experiments were carried out in a laboratory designed according to the standard EN54-9. The laboratory was instrumented with additional equipment such as thermocouples and flow meters which are not used in standard fire sensitivity tests. This allows the results to be used as experimental data for validation tasks of numerical fire simulation computerized fluid dynamics (CFD)-codes. The ultimate goal of the research is to model theoretically smoldering and flaming cable fires, their smoke production, transfer of smoke to detectors, as well as the response of detectors and fire alarm systems to potential fires. This would allow the use of numerical fire simulation to predict fire hazards in different fire scenarios found important in PSA (probability safety assessment) of NPPs. This report concentrates on explaining full-scale fire experiments in the smoke sensitivity laboratory and experimental results from fire tests of detectors. Validation tasks with CFD-codes will be first carried out `blind` without any idea about corresponding experimental results. Accordingly, the experimental results cannot be published in this report. (orig.). 12 refs.

  9. Critical wind velocity for arresting upwind gas and smoke dispersion induced by near-wall fire in a road tunnel.

    Science.gov (United States)

    Hu, L H; Peng, W; Huo, R

    2008-01-15

    In case of a tunnel fire, toxic gas and smoke particles released are the most fatal contaminations. It is important to supply fresh air from the upwind side to provide a clean and safe environment upstream from the fire source for people evacuation. Thus, the critical longitudinal wind velocity for arresting fire induced upwind gas and smoke dispersion is a key criteria for tunnel safety design. Former studies and thus, the models built for estimating the critical wind velocity are all arbitrarily assuming that the fire takes place at the centre of the tunnel. However, in many real cases in road tunnels, the fire originates near the sidewall. The critical velocity of a near-wall fire should be different with that of a free-standing central fire due to their different plume entrainment process. Theoretical analysis and CFD simulation were performed in this paper to estimate the critical velocity for the fire near the sidewall. Results showed that when fire originates near the sidewall, it needs larger critical velocity to arrest the upwind gas and smoke dispersion than when fire at the centre. The ratio of critical velocity of a near-wall fire to that of a central fire was ideally estimated to be 1.26 by theoretical analysis. Results by CFD modelling showed that the ratio decreased with the increase of the fire size till near to unity. The ratio by CFD modelling was about 1.18 for a 500kW small fire, being near to and a bit lower than the theoretically estimated value of 1.26. However, the former models, including those of Thomas (1958, 1968), Dangizer and Kenndey (1982), Oka and Atkinson (1995), Wu and Barker (2000) and Kunsch (1999, 2002), underestimated the critical velocity needed for a fire near the tunnel sidewall.

  10. Influence analysis of flow rule in mine fire during injecting inert gases

    Institute of Scientific and Technical Information of China (English)

    NIU Hui-yong; WANG Hai-qiao

    2011-01-01

    According to the action law of gas flow during injecting inert gases as the research main line,and hydromechanics and thermodynamics theories,the characteristic of gas delamination that was caused by injecting inert gases to closed fire zone was analyzed.The criterion was brought forward,which could scale disappearing probability of turbulent state.Formation mechanism of gas layer in turbulent state was discussed primarily.Simultaneously,the condition was pointed out,which could make the gas in turbulent state by injecting different gases.The mathematical model about dynamic changes of oxygen and methane concentration in the process of injecting gases was erected.The mixture mechanism about injecting different flow inert gases and flammable gas layer in closed fire zone was revealed.

  11. Fire analysis in the eighteenth century: Herman Boerhaave and scepticism about the elements.

    Science.gov (United States)

    Powers, John C

    2014-11-01

    In the eighteenth century, many chemists asserted that chemical operations could not decompose a substance into its natural, constituent elements or principles. One such chemist was Herman Boerhaave (1668-1738), who claimed, following the work of Robert Boyle and Joan Baptista van Helmont, that examples of these alleged analyses were, in fact, not reductions of a body into elements, but rather the rearrangement of its particles by the fire. Since we cannot observe the shape and arrangement of particles directly, he reasoned, any claim regarding the elemental status of a substance was purely speculative and inadmissible in his chemistry. As a result, Boerhaave devised a system of chemistry which, in effect, accepted no elemental substances and which focused on understanding how the chemist's 'instruments,' including fire and chemical menstrua, effected changes in matter. I conclude by showing how Boerhaave's conclusion had ramifications for later developments in chemistry, especially those of the French Stahlians and of Antione Lavoisier.

  12. An analysis of motor unit firing pattern during sustained low force contraction in fatigued muscle.

    Science.gov (United States)

    Olsen, H B; Christensen, H; Søgaard, K

    2001-01-01

    In the present study motor unit (MU) firing pattern was analysed during long-term static contraction in order to see if fatigue would induce rotation of activity between different MU. Surface as well as intramuscular EMG were obtained from ten subjects during a sustained hand lift for 5 minutes after performance of a 30% MVC fatiguing contraction of the extensor carpi radialis muscle. A newly developed decomposition program constituted a powerful tool to obtain detailed knowledge of long term activity pattern of MU during low force contractions. Although the muscle was highly fatigued the majority of MU showed a continuous firing pattern after recruitment and no clear incidences of rotation were found for any of the subjects. Therefore, long term, low force contractions, as performed during many occupational work tasks, may involve continuous activation of the low threshold MU and this could have mechanical as well as metabolic implications for these muscle fibers.

  13. Probabilistic buckling analysis of the beam steel structures subjected to fire by the stochastic finite element method

    Directory of Open Access Journals (Sweden)

    Świta P.

    2016-05-01

    Full Text Available The main purpose is to present the stochastic perturbation-based Finite Element Method analysis of the stability in the issues related to the influence of high temperature resulting from a fire directly connected with the reliability analysis of such structures. The thin-walled beam structures with constant cross-sectional thickness are uploaded with typical constant loads, variable loads and, additionally, a temperature increase and we look for the first critical value equivalent to the global stability loss. Such an analysis is carried out in the probabilistic context to determine as precisely as possible the safety margins according to the civil engineering Eurocode statements. To achieve this goal we employ the additional design-oriented Finite Element Method program and computer algebra system to get the analytical polynomial functions relating the critical pressure (or force and several random design parameters; all the models are state-dependent as we consider an additional reduction of the strength parameters due to the temperature increase. The first four probabilistic moments of the critical forces are computed assuming that the input random parameters have all Gaussian probability functions truncated to the positive values only. Finally, the reliability index is calculated according to the First Order Reliability Method (FORM by an application of the limit function as a difference in-between critical pressure and maximum compression stress determined in the given structures to verify their durability according to the demands of EU engineering designing codes related to the fire situation.

  14. Probabilistic buckling analysis of the beam steel structures subjected to fire by the stochastic finite element method

    Science.gov (United States)

    Świta, P.; Kamiński, M.

    2016-05-01

    The main purpose is to present the stochastic perturbation-based Finite Element Method analysis of the stability in the issues related to the influence of high temperature resulting from a fire directly connected with the reliability analysis of such structures. The thin-walled beam structures with constant cross-sectional thickness are uploaded with typical constant loads, variable loads and, additionally, a temperature increase and we look for the first critical value equivalent to the global stability loss. Such an analysis is carried out in the probabilistic context to determine as precisely as possible the safety margins according to the civil engineering Eurocode statements. To achieve this goal we employ the additional design-oriented Finite Element Method program and computer algebra system to get the analytical polynomial functions relating the critical pressure (or force) and several random design parameters; all the models are state-dependent as we consider an additional reduction of the strength parameters due to the temperature increase. The first four probabilistic moments of the critical forces are computed assuming that the input random parameters have all Gaussian probability functions truncated to the positive values only. Finally, the reliability index is calculated according to the First Order Reliability Method (FORM) by an application of the limit function as a difference in-between critical pressure and maximum compression stress determined in the given structures to verify their durability according to the demands of EU engineering designing codes related to the fire situation.

  15. Analysis and simulation of Wiseman hypocycloid engine

    Directory of Open Access Journals (Sweden)

    Priyesh Ray

    2014-12-01

    Full Text Available This research studies an alternative to the slider-crank mechanism for internal combustion engines, which was proposed by the Wiseman Technologies Inc. Their design involved replacing the crankshaft with a hypocycloid gear assembly. The unique hypocycloid gear arrangement allowed the piston and connecting rod to move in a straight line creating a perfect sinusoidal motion, without any side loads. In this work, the Wiseman hypocycloid engine was modeled in a commercial engine simulation software and compared to slider-crank engine of the same size. The engine’s performance was studied, while operating on diesel, ethanol, and gasoline fuel. Furthermore, a scaling analysis on the Wiseman engine prototypes was carried out to understand how the performance of the engine is affected by increasing the output power and cylinder displacement. It was found that the existing 30cc Wiseman engine produced about 7% less power at peak speeds than the slider-crank engine of the same size. These results were concurrent with the dynamometer tests performed in the past. It also produced lower torque and was about 6% less fuel efficient than the slider-crank engine. The four-stroke diesel variant of the same Wiseman engine performed better than the two-stroke gasoline version. The Wiseman engine with a contra piston (that allowed to vary the compression ratio showed poor fuel efficiency but produced higher torque when operating on E85 fuel. It also produced about 1.4% more power than while running on gasoline. While analyzing effects of the engine size on the Wiseman hypocycloid engine prototypes, it was found that the engines performed better in terms of power, torque, fuel efficiency, and cylinder brake mean effective pressure as the displacement increased. The 30 horsepower (HP conceptual Wiseman prototype, while operating on E85, produced the most optimum results in all aspects, and the diesel test for the same engine proved to be the most fuel efficient.

  16. On fire

    DEFF Research Database (Denmark)

    Hansen, Helle Rabøl

    The title of this paper: “On fire”, refers to two (maybe three) aspects: firstly as a metaphor of having engagement in a community of practice according to Lave & Wenger (1991), and secondly it refers to the concrete element “fire” in the work of the fire fighters – and thirdly fire as a signifier...

  17. Fire Power

    Science.gov (United States)

    Denker, Deb; West, Lee

    2009-01-01

    For education administrators, campus fires are not only a distressing loss, but also a stark reminder that a campus faces risks that require special vigilance. In many ways, campuses resemble small communities, with areas for living, working and relaxing. A residence hall fire may raise the specter of careless youth, often with the complication of…

  18. What are the most fire-dangerous atmospheric circulations in the Eastern-Mediterranean? Analysis of the synoptic wildfire climatology.

    Science.gov (United States)

    Paschalidou, A K; Kassomenos, P A

    2016-01-01

    Wildfire management is closely linked to robust forecasts of changes in wildfire risk related to meteorological conditions. This link can be bridged either through fire weather indices or through statistical techniques that directly relate atmospheric patterns to wildfire activity. In the present work the COST-733 classification schemes are applied in order to link wildfires in Greece with synoptic circulation patterns. The analysis reveals that the majority of wildfire events can be explained by a small number of specific synoptic circulations, hence reflecting the synoptic climatology of wildfires. All 8 classification schemes used, prove that the most fire-dangerous conditions in Greece are characterized by a combination of high atmospheric pressure systems located N to NW of Greece, coupled with lower pressures located over the very Eastern part of the Mediterranean, an atmospheric pressure pattern closely linked to the local Etesian winds over the Aegean Sea. During these events, the atmospheric pressure has been reported to be anomalously high, while anomalously low 500hPa geopotential heights and negative total water column anomalies were also observed. Among the various classification schemes used, the 2 Principal Component Analysis-based classifications, namely the PCT and the PXE, as well as the Leader Algorithm classification LND proved to be the best options, in terms of being capable to isolate the vast amount of fire events in a small number of classes with increased frequency of occurrence. It is estimated that these 3 schemes, in combination with medium-range to seasonal climate forecasts, could be used by wildfire risk managers to provide increased wildfire prediction accuracy.

  19. FDTD simulation tools for UWB antenna analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Brocato, Robert Wesley

    2004-12-01

    This paper describes the development of a set of software tools useful for analyzing ultra-wideband (UWB) antennas and structures. These tools are used to perform finite difference time domain (FDTD) simulation of a conical antenna with continuous wave (CW) and UWB pulsed excitations. The antenna is analyzed using spherical coordinate-based FDTD equations that are derived from first principles. The simulation results for CW excitation are compared to simulation and measured results from published sources; the results for UWB excitation are new.

  20. Energy penalty analysis of possible cooling water intake structurerequirements on existing coal-fired power plants.

    Energy Technology Data Exchange (ETDEWEB)

    Veil, J. A.; Littleton, D. J.; Gross, R. W.; Smith, D. N.; Parsons, E.L., Jr.; Shelton, W. W.; Feeley, T. J.; McGurl, G. V.

    2006-11-27

    from converting plants with once-through cooling to wet towers or indirect-dry towers. Five locations--Delaware River Basin (Philadelphia), Michigan/Great Lakes (Detroit), Ohio River Valley (Indianapolis), South (Atlanta), and Southwest (Yuma)--were modeled using an ASPEN simulator model. The model evaluated the performance and energy penalty for hypothetical 400-MW coal-fired plants that were retrofitted from using once-through cooling systems to wet- and dry-recirculating systems. The modeling was initially done to simulate the hottest time of the year using temperature input values that are exceeded only 1 percent of the time between June through September at each modeled location. These are the same temperature inputs commonly used by cooling tower designers to ensure that towers perform properly under most climatic conditions.

  1. Nutrient cycling responses to fire frequency in the Kruger National Park (South Africa) as indicated by stable isotope analysis.

    Science.gov (United States)

    Aranibar, J N; Macko, S A; Anderson, I C; Potgieter, A L E; Sowry, R; Shugart, H H

    2003-06-01

    Fires, which are an intrinsic feature of southern African ecosystems, produce biogenic and pyrogenic losses of nitrogen (N) from plants and soils. Because of the long history of fires in these savannas, it was hypothesized that N2 fixation by legumes balances the N losses caused by fires. In this study, the N2 fixation activity of woody legumes was estimated by analyzing foliar delta15N and proportional basal area of N2 fixing species along experimental fire gradients in the Kruger National Park (South Africa). In addition, soil carbon (C) and N pools, foliar phosphorus (P) and gross N mineralization and nitrification rates were measured, to indicate the effects of fires on nutrient stocks and the possible N cycling processes modified by fires. Although observations of increased soil C/N and mineralization rates in frequently burned plots support previous reports of N losses caused by fires, soil %N did not decrease with increasing fire frequency (except in 1 plot), suggesting that N losses are replenished in burned areas. However, relative abundance and N2 fixation of woody legumes decreased with fire frequency in two of the three fire gradients analyzed, suggesting that woody legume N2 fixation is not the mechanism that balances N losses. The relatively constant %N along fire gradients suggests that these ecosystems have other mechanisms to balance the N lost by fires, which could include inputs by atmospheric deposition and N2 fixation by forbs, grasses and soil cyanobacteria. Soil isotopic signatures have been previously used to infer patterns of fire history. However, the lack of a relationship between soil delta15N and fire frequency found in this study indicates that the effects of fires on ecosystem delta15N are unpredictable. Similar soil delta15N along fire gradients may reflect the contrasting effects of increased N gaseous emissions (which increases delta15N) and N2 fixation other than that associated with woody legumes (which lowers delta15N) on

  2. Economic Analysis for Rebuilding of an Aged Pulverized Coal-Fired Boiler with a New Boiler in an Aged Thermal Power Plant

    Directory of Open Access Journals (Sweden)

    Burhanettin Cetin

    2013-01-01

    Full Text Available Fossil-fired thermal power plants (TPP produce a significant part of electricity in the world. Because of the aging TPPs and so their equipment (especially boiler, thermal power plants also produce less power than their installed capacities, and there has been power loss in time. This situation affects the supply and demand balance of countries. For this reason, aging equipments such as pulverized coal-fired boiler (PCB must be renewed and power loss must be recovered, instead of building new TPPs. In this study, economic analysis of rebuilding an aged pulverized coal-fired boiler with a new pulverized coal-fired boiler including flue gas desulfurization (FGD unit and a circulating fluidized bed boiler (FBB are investigated in an existing old TPP. Emission costs are also added to model, and the developed model is applied to a 200 MWe pulverized coal-fired thermal power plant in Turkey. As a result, the payback period and the net present value are calculated for different technical and economic parameters such as power loss, load factor, electricity price, discount rate, and escalation rate by using the annual value method. The outcomes of this study show that rebuilding of a pulverized coal-fired boiler with a new one is amortized itself in a very short time.

  3. Schedule Risk Analysis Simulator using Beta Distribution

    Directory of Open Access Journals (Sweden)

    Isha Sharma,

    2011-06-01

    Full Text Available This paper describes an application of simulation and Modelling in Software risk management. This paper describes a simulation based software risk management tool which helps manager to identifyhigh risk areas of software process. In this paper an endeavour has been made to build up a Stochastic Simulator which helps in decision making to identify the critical activities which are given due priorities during the development of Software Project. In response to new information or revised estimates, it may be necessary to reassign resources, cancel optional tasks, etc. Project management tools that make projections while treating decisions about tasks and resource assignments as static will not yield realistic results. The usual PERT procedure may lead to overly optimistic results as many pass which are not critical but slightly shorter than critical on the basis of estimated activity duration or average durations.Due to randomness of durations, these pass under some combination of activity durations, could become longer than the average longest path. Such paths would be ignored while using the PERT technique onthe basis of the average durations. In order to overcome this problem and be more reasonable, the said Stochastic Simulator has been designed by generating random samples from a specific probabilitydistribution associated with that particular activity of SPM. The said simulator is also not bugged with overly estimated results.

  4. Evaluation of deriving fire cycle of forested landscape based on time-since-fire distribution

    Institute of Scientific and Technical Information of China (English)

    ZHANG Quan-fa; Kurt S. Pregitzer; JIANG Ming-xi; CHEN Wen-jun

    2006-01-01

    Estimation of fire cycle has been conducted by using the negative exponential function as an approximation of time-since-fire distribution of a landscape assumed .to be homogeneous with respect to fire spread processes. The authors imposed predefined fire cycles on a virtual landscape of 100 cell ×100 cell, and obtained a mosaic composing of patches with different stand ages (i.e. time since fire). Graphical and statistical methods (Van Wagner 1978; Reed et al. 1998) were employed to derive fire cycle from the virtual landscape. By comparing the predefined and the derived fire cycles, the two methods and tested the effects of sample size and hazard of burning (i.e., stand's susceptibility to fire in relation to its stand age) were evaluated on fire cycle deviation. The simulation results indicated a minimum sample size of 10 times of the annual burnt area would be required for partitioning time-since-fire distribution into homogeneous epochs indicating temporal change in fire cycle. Statistically, there was significant difference among the imposed and the derived fire cycle, regardless of sample sizes with or without consideration of hazard of burning. Both methods underestimated the more recent fire cycle without significant difference between them. The results imply that deviation of fire cycle based on time-since-fire distribution warrants cautious interpretation, especially when a landscape is spatially partitioned into small units and temporal changes in fire cycle are involved.

  5. FDS Modeling of the Sensitivity of the Smoke Potential Values Used in Fire Safety Strategies

    DEFF Research Database (Denmark)

    Corches, Andrei-Mircea; Ulriksen, Lene; Jomaas, Grunde

    2014-01-01

    both from a geometrical and functional point of view, this type of comparison typically rely on numerical simulation methods, such as, computation fluid dynamics (CFD), to assess the amount of heat and smoke produced during fires and to estimate the transport of the combustion products. After...... the numerical simulation methods were adopted to simulate fires in buildings in Denmark, it has been observed that, for a majority of fire strategy reports, the optical properties of the smoke determine the available safe egress time. These critical times are most often defined by the visibility criteria...... defined in the Danish performance-based fire design code [1]. As there is no uniform test method to measure the optical properties of the smoke, values from different experiments are used in engineering analysis to express the properties that determine the decrease of visibility through smoke [2...

  6. The effect of simulated heat-shock and daily temperature fluctuations on seed germination of four species from fire-prone ecosystems

    Directory of Open Access Journals (Sweden)

    Talita Zupo

    2016-01-01

    Full Text Available ABSTRACT Seed germination in many species from fire-prone ecosystems may be triggered by heat shock and/or temperature fluctuation, and how species respond to such fire-related cues is important to understand post-fire regeneration strategies. Thus, we tested how heat shock and daily temperature fluctuations affect the germination of four species from fire-prone ecosystems; two from the Cerrado and two from the Mediterranean Basin. Seeds of all four species were subjected to four treatments: Fire (F, temperature fluctuations (TF, fire+temperature fluctuations (F+TF and control (C. After treatments, seeds were put to germinate for 60 days at 25ºC (dark. Responses differed according to species and native ecosystem. Germination percentage for the Cerrado species did not increase with any of the treatments, while germination of one Mediterranean species increased with all treatments and the other only with treatments that included fire. Although the Cerrado species did not respond to the treatments used in this study, their seeds survived the exposure to heat shock, which suggests they possess tolerance to fire. Fire frequency in the Cerrado is higher than that in Mediterranean ecosystems, thus traits related to fire-resistance would be more advantageous than traits related to post-fire recruitment, which are widespread among Mediterranean species.

  7. A Monte Carlo analysis of health risks from PCB-contaminated mineral oil transformer fires.

    Science.gov (United States)

    Eschenroeder, A Q; Faeder, E J

    1988-06-01

    The objective of this study is the estimation of health hazards due to the inhalation of combustion products from accidental mineral oil transformer fires. Calculations of production, dispersion, and subsequent human intake of polychlorinated dibenzofurans (PCDFs) provide us with exposure estimates. PCDFs are believed to be the principal toxic products of the pyrolysis of polychlorinated biphenyls (PCBs) sometimes found as contaminants in transformer mineral oil. Cancer burdens and birth defect hazard indices are estimated from population data and exposure statistics. Monte Carlo-derived variational factors emphasize the statistics of uncertainty in the estimates of risk parameters. Community health issues are addressed and risks are found to be insignificant.

  8. EFP Warhead Missile Fuze Analysis and Simulation

    Institute of Scientific and Technical Information of China (English)

    LI Wei; FAN Ning-jun; WANG Zheng-jie

    2008-01-01

    The explosive formed penetrator(EFP)warhead missile projects the blast fragments in one direction normal to the missile longitudinal axis.Through analyzing on the two restrictions of EFP warhead explosion:trajectory restriction and attitude requirement,the concept of fuse time-delay tolerance is presented to be the measurement of the time of the EFP warhead explosion.The calculation models of fuze time-delaY tolerance under two restrictions are provided.Some crucial parameters playing important roles in calculation under attitude requirements are simulated.The simulation results show that the engagement plane angle,roll rate and warhead attack standoff influence the tolerance dramatically.

  9. HSIP Fire Stations in New Mexico

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — Fire Stations in New Mexico Any location where fire fighters are stationed or based out of, or where equipment that such personnel use in carrying out their jobs is...

  10. Analysis of natural radionuclides in coal, slag and ash in coal-fired power plants in Serbia

    Directory of Open Access Journals (Sweden)

    Janković M.M.

    2011-01-01

    Full Text Available The radioactivity monitoring in the “Nikola Tesla”, “Kolubara”, “Morava” and “Kostolac” coal-fired power plants was performed by the Radiation and Environmental Protection Laboratory, Vinča Institute of nuclear sciences in the period 2003-2010. Monitoring included the analysis of soil, water, flying ash, slag, coal and plants. This paper presents the results of the radioactivity analysis of coal, ash and slag samples. Naturally occurring radionuclides 226Ra, 232Th, 40K, 235U, 238U, and 210Pb as well as the man-made radionuclide 137Cs were determined by gamma spectrometry using HPGe detector. The concentrations of pairs of radionuclides were statistically tested to determine the correlation between them. Based on the obtained results, health effect due to the activity of these radionuclides was estimated via radium equivalent (Raeq, external hazard index (Hex, external gamma absorbed dose rate ( and annual effective dose.

  11. The fire effect on Cerrado: Analysis of the erosive process associated with native vegetation by the use of experimental plots

    Science.gov (United States)

    Costa, Yasmmin; Rodrigues, Sílvio

    2015-04-01

    In Brazil vast areas of vegetation are devastated each year by the use of fire that recorded more than 200,000 hotspots annually. In this context, the state of Minas Gerais appears first in the number of fires and burned areas due to its long stretch of reforested area in an environment where a prolonged dry season contributes to the occurrence and spread of fire in the Cerrado vegetation. This research consists of a comparative study through the controlled application of fire under different conditions of natural vegetation of the focusing on the change in rates of runoff, sediment production and vegetation density in order to evaluate the influence of burning related to soil erosion. The area of study is located in Uberlândia at an altitude of 850 meters above sea level and in the respective geographic coordinates 18°56'56"S and 48°12'21"W that composes the watershed of Glória stream. The climate is characterized by dry winters and rainy summer. On this area five experimental plots was established from the specific characteristic of its vegetation cover, slope and drainage, thus differentiated: well drained soil with the presence of a dense grass (plot A), well drained soil with the presence of shrub and grasses (plot B), poorly drained with a non-dense grass (plot C), well drained soil with grass (plot D), and well drained with grasses and tree cover(plot E). The plots have 1m2 that is connected with a trough collector that concentrate the water flow generated by runoff with a 30 liter gallon that was weekly measured. The data relating to runoff and sediment yield were obtained from the collection of water derived from water stored in gallons, in which first was homogenized, measured quantity and collected 1 liter of water to be filtrated in the laboratory. The analysis method of vegetation density was performed based on the methodology proposed by Pinese Junior, Cruz and Rodrigues (2008), using the software ENVI 4.3 to interpret and quantify the image

  12. In situ and in-transit analysis of cosmological simulations

    Science.gov (United States)

    Friesen, Brian; Almgren, Ann; Lukić, Zarija; Weber, Gunther; Morozov, Dmitriy; Beckner, Vincent; Day, Marcus

    2016-08-01

    Modern cosmological simulations have reached the trillion-element scale, rendering data storage and subsequent analysis formidable tasks. To address this circumstance, we present a new MPI-parallel approach for analysis of simulation data while the simulation runs, as an alternative to the traditional workflow consisting of periodically saving large data sets to disk for subsequent `offline' analysis. We demonstrate this approach in the compressible gasdynamics/ N-body code Nyx, a hybrid MPI+OpenMP code based on the BoxLib framework, used for large-scale cosmological simulations. We have enabled on-the-fly workflows in two different ways: one is a straightforward approach consisting of all MPI processes periodically halting the main simulation and analyzing each component of data that they own (` in situ'). The other consists of partitioning processes into disjoint MPI groups, with one performing the simulation and periodically sending data to the other `sidecar' group, which post-processes it while the simulation continues (`in-transit'). The two groups execute their tasks asynchronously, stopping only to synchronize when a new set of simulation data needs to be analyzed. For both the in situ and in-transit approaches, we experiment with two different analysis suites with distinct performance behavior: one which finds dark matter halos in the simulation using merge trees to calculate the mass contained within iso-density contours, and another which calculates probability distribution functions and power spectra of various fields in the simulation. Both are common analysis tasks for cosmology, and both result in summary statistics significantly smaller than the original data set. We study the behavior of each type of analysis in each workflow in order to determine the optimal configuration for the different data analysis algorithms.

  13. Mathematical Analysis and Simulation of Crop Micrometeorology

    NARCIS (Netherlands)

    Chen, J.

    1984-01-01

    In crop micrometeorology the transfer of radiation, momentum, heat and mass to or from a crop canopy is studied. Simulation models for these processes do exist but are not easy to handle because of their complexity and the long computing time they need. Moreover, up to now such models can only be ru

  14. Numerical simulation of ventilation modes in underground railway tunnel fire%地铁区间隧道火灾通风模式的数值模拟

    Institute of Scientific and Technical Information of China (English)

    高明亮; 朱常琳

    2013-01-01

    In view of the fire occuring in the middle part of the train and the train stopping in the middle of the tunnel, proposes an improved longitudinal ventilation mode i.e. supplying air first from the lower side of the evacuation platform and then adopting conventional longitudinal ventilation mode, and numerically simulates its effect at this case. The results show that for the single track rectanglar cross-section tunnel and the fire intensity of 10 MW, air supply outlet group spacing 10 m and air volume of tunnel ventilation fan of 50 irrVs, or air supply outlet group spacing less than 30 m and air volume of 70 rrrVs, can meet the requirements of fire safety for temperature, visibility and CO concentration limits. Also obtains that the critical wind velocity for longitudinal ventilation on both ends of underground railway tunnel is 2.4 to 2.8 m/s.%针对列车中部着火且停靠在区间隧道中部的地铁隧道火灾情况,提出了一种改进的纵向通风模式,即疏散平台下先送风、再采用传统的纵向通风,并进行了数值模拟.模拟结果表明,时单线矩形区间隧道,在10 MW的火源强度下,当疏散平台下送风风口组间距为10m且隧道风机风量为50 m3/s时(或风口组间距不超过30 m且隧道风机风量为70m3/s时),可以满足安全消防的温度指标、能见度指标和CO浓度指标.同时模拟得出区间隧道两端纵向通风的临界风速在2.4~2.8 m/s之间.

  15. Practical Thermal Evaluation Methods For HAC Fire Analysis In Type B Radiaoactive Material (RAM) Packages

    Energy Technology Data Exchange (ETDEWEB)

    Abramczyk, Glenn; Hensel, Stephen J; Gupta, Narendra K.

    2013-03-28

    Title 10 of the United States Code of Federal Regulations Part 71 for the Nuclear Regulatory Commission (10 CFR Part 71.73) requires that Type B radioactive material (RAM) packages satisfy certain Hypothetical Accident Conditions (HAC) thermal design requirements to ensure package safety during accidental fire conditions. Compliance with thermal design requirements can be met by prototype tests, analyses only or a combination of tests and analyses. Normally, it is impractical to meet all the HAC using tests only and the analytical methods are too complex due to the multi-physics non-linear nature of the fire event. Therefore, a combination of tests and thermal analyses methods using commercial heat transfer software are used to meet the necessary design requirements. The authors, along with his other colleagues at Savannah River National Laboratory in Aiken, SC, USA, have successfully used this 'tests and analyses' approach in the design and certification of several United States' DOE/NNSA certified packages, e.g. 9975, 9977, 9978, 9979, H1700, and Bulk Tritium Shipping Package (BTSP). This paper will describe these methods and it is hoped that the RAM Type B package designers and analysts can use them for their applications.

  16. Determinants of National Fire Plan Fuels Treatment Expenditures: A Revealed Preference Analysis for Northern New Mexico

    Science.gov (United States)

    Shepherd, Curt; Grimsrud, Kristine; Berrens, Robert P.

    2009-10-01

    The accumulation of fire fuels in forests throughout the world contributes significantly to the severity of wildfires. To combat the threat of wildfire, especially in the wildland-urban interface (WUI), US federal land management agencies have implemented a number of forest restoration and wildfire risk reduction programs. In the spirit of revealed preference analyses, the objective of this study is to investigate the pattern and determinants of National Fire Plan (NFP) expenditures for fuel reduction treatments in northern New Mexico (USA). Estimation results from a set of Generalized Estimating Equations models are mixed with respect to risk reduction hypotheses, and also raise issues regarding how risk reduction should be defined for a region characterized by both pockets of urban sprawl into the WUI and large areas of chronic rural poverty. Program preferences for project funding under the federal Collaborative Forest Restoration Program in New Mexico are shown to be distinctly different (e.g., exhibiting greater concern for social equity) than for other NFP-funded projects.

  17. Determinants of national fire plan fuels treatment expenditures: a revealed preference analysis for northern New Mexico.

    Science.gov (United States)

    Shepherd, Curt; Grimsrud, Kristine; Berrens, Robert P

    2009-10-01

    The accumulation of fire fuels in forests throughout the world contributes significantly to the severity of wildfires. To combat the threat of wildfire, especially in the wildland-urban interface (WUI), US federal land management agencies have implemented a number of forest restoration and wildfire risk reduction programs. In the spirit of revealed preference analyses, the objective of this study is to investigate the pattern and determinants of National Fire Plan (NFP) expenditures for fuel reduction treatments in northern New Mexico (USA). Estimation results from a set of Generalized Estimating Equations models are mixed with respect to risk reduction hypotheses, and also raise issues regarding how risk reduction should be defined for a region characterized by both pockets of urban sprawl into the WUI and large areas of chronic rural poverty. Program preferences for project funding under the federal Collaborative Forest Restoration Program in New Mexico are shown to be distinctly different (e.g., exhibiting greater concern for social equity) than for other NFP-funded projects.

  18. Simulation of Effect of Smoke Exhaust on Smoke Characteristics in Long Corridor Fire%排烟对狭长空间火灾烟气特性影响的模拟

    Institute of Scientific and Technical Information of China (English)

    任广鲁; 邱金水; 刘伯运; 易祥烈

    2016-01-01

    移动排烟机由于其自身使用的灵活性,被广泛用于火场排烟。以能见度及温度为指标,对狭长空间火灾发生时使用移动排烟机进行排烟的效果进行了大涡模拟。分析结果表明:在不采用任何排烟措施的情况下,烟气蔓延速度快、温度高,容易出现“游走火”现象,可能造成难以预估的伤害;采取正压送风或负压排风的排烟方式对提高空间能见度及降低空间温度有显著作用;正压送风与负压排风联合使用效果不如单独使用一种排烟方式。%As its own flexibility,portable smoke exhausted fan is widely used in exhausting smoking in fire.Visibility and temperature were taken as the index to simulate the effect of portable smoke exhaust fan in long corridor fire.The analysis results show that in the case of not using any smoke control measures, the long corridor smoke spreads fast and the temperature is high,where is prone to appear “ghosting phe-nomenon”,which may cause unpredictable damage.And the positive pressure blowing or negative pres-sure drainage is helpful to improve the visibility of the space and to reduce the space temperature.The joint effect of positive pressure blowing and negative pressure drainage is not as good as using single method.

  19. Reconstruction of fire spread within wildland fire events in Northern Eurasia from the MODIS active fire product

    Science.gov (United States)

    Loboda, T. V.; Csiszar, I. A.

    2007-04-01

    Russian boreal forests have been reshaped by wildland fire for millennia. While fire is a natural component of boreal ecosystems, it impacts various aspects of the environment and affects human well-being. Often fires occur over large remote areas with limited access, which makes their ground-based observation difficult. A significant progress has been made in mapping burned area from satellite imagery, which provides consistent and fairly unbiased estimates of fire impact on areas of interest at multiple scales. Although the information provided by burned area products is highly important, the spatio-temporal dynamics of individual fire events and their impact are less known. In high northern latitudes of Northern Eurasia, MODIS (Moderate Resolution Imaging Spectroradiometer) makes up to four daily observations from each of the Terra and Aqua satellites providing consistent data on fire development with high temporal frequency. Here we introduce an approach to reconstruct the development of fire events based on active fire detections from MODIS. Fire Spread Reconstruction (FSR) provides a means for characterization of fire occurrence over large territories from remotely sensed data. Individual fire detections are clustered within a GIS environment based on a set of rules determining proximity between fire observations in space and time. FSR determines the number of fire events, their approximate size, duration, and fire spread rate and allows for the analysis of fire occurrence and spread as a function of vegetation, fire season, fire weather and other parameters. FSR clusters were compared to burned scars mapped from Landsat7/ETM+ imagery over Yakutia (Russia). While some smaller burn scars were found to be formed through a continuous burning of a single fire event, large burned areas in Siberia were created by a constellation of fire events incorporating over 100 individual fire clusters. Geographic regions were found to have a stronger influence on the rates of

  20. 基于Simulink的水灭火系统仿真研究%Water Fire Fighting System Simulation Based on Simulink

    Institute of Scientific and Technical Information of China (English)

    丁相; 王春平

    2014-01-01

    该文提出一种新的基于Visual c++的水灭火系统仿真模型,通过将C++代码转换成C代码植入到仿真模型中,可以大大优化仿真模型的开发,该文中Simulink软件和VSULAL C++软件的优点在仿真模型中得到完整的体现。该文还详细讨论了水灭火仿真系统的开发和实现。%This paper presents an approach to integrate simulation model with Visual C++easily by translating simulation model to embedded C++code. Then the advantages of Simulink and Visual C++are fully used by this approach. According to a real example the development steps and realization of water fire fighting system based on this approach is discussed in detail.

  1. Three-dimensional Simulations of the Mean Air Transport During the 1997 Forest Fires in Kalimantan, Indonesia Using a Mesoscale Numerical Model

    Science.gov (United States)

    Roswintiarti, O.; Raman, S.

    - This paper describes the meteorological processes responsible for the mean transport of air pollutants during the ENSO-related forest fires in Kalimantan, Indonesia from 00 UTC 21 September to 00 UTC 25 September, 1997. The Fifth Generation of the Pennsylvania State University-National Center for Atmospheric Research (PSU-NCAR) Mesoscale Model (MM5) is used to simulate three-dimensional winds at 6-hourly intervals. A nonhydrostatic version of the model is run using two nested grids with horizontal resolutions of 45 km and 15 km. From the simulated wind fields, the backward and forward trajectories of the air parcel are investigated using the Vis5D model.The results indicate that the large-scale subsidence over Indonesia, the southwest monsoon low-level flows (2-8 m s-1), and the shallow planetary boundary layer height (400-800 m) play a key role in the transport of air pollutants from Kalimantan to Malaysia, Singapore and Brunei.

  2. Synchronization of firing in cortical fast-spiking interneurons at gamma frequencies: a phase-resetting analysis.

    Directory of Open Access Journals (Sweden)

    Nathan W Gouwens

    Full Text Available Fast-spiking (FS cells in the neocortex are interconnected both by inhibitory chemical synapses and by electrical synapses, or gap-junctions. Synchronized firing of FS neurons is important in the generation of gamma oscillations, at frequencies between 30 and 80 Hz. To understand how these synaptic interactions control synchronization, artificial synaptic conductances were injected in FS cells, and the synaptic phase-resetting function (SPRF, describing how the compound synaptic input perturbs the phase of gamma-frequency spiking as a function of the phase at which it is applied, was measured. GABAergic and gap junctional conductances made distinct contributions to the SPRF, which had a surprisingly simple piecewise linear form, with a sharp midcycle break between phase delay and advance. Analysis of the SPRF showed how the intrinsic biophysical properties of FS neurons and their interconnections allow entrainment of firing over a wide gamma frequency band, whose upper and lower frequency limits are controlled by electrical synapses and GABAergic inhibition respectively.

  3. The validation and analysis of novel stereo-derived smoke plume products from AATSR and their application to fire events from the 2008 Russian fire season

    Science.gov (United States)

    Fisher, D.; Muller, J.-P.; Yershov, V.

    2012-04-01

    Burning as a Source of Atmospheric Gases Co, H-2, N2o, No, Ch3cl and Cos." Nature 282(5736): 253-256. [2] Martin, M. V., J. A. Logan, et al. (2010). "Smoke injection heights from fires in North America: analysis of 5 years of satellite observations." Atmospheric Chemistry and Physics 10(4): 1491-1510. [3] Muller, J. P., M. A. Denis, et al. (2007). "Stereo cloud-top heights and cloud fraction retrieval from ATSR-2." International Journal of Remote Sensing 28(9): 1921-1938. [4] Muller, J.-P., A. Mandanyake, et al. (2002). "MISR stereoscopic image matchers: Techniques and results." IEEE Transactions on Geoscience and Remote Sensing 40: 1547-1559. [5] Fisher, D.N., Muller, J.-P., Yershov, V.N. (2012) "Automated Smoke Plume Injection Heights (SPIH) and Smoke-Plume Masks (SPM) from AATSR stereo for mapping aerosol and trace gas injection into the free troposphere", Remote Sensing of Environment (in review)

  4. Fire Safety

    Science.gov (United States)

    ... Turn off Animations Turn on Animations Our Sponsors Log in | Register Menu Log in | Register Home Our Sponsors Ages & Stages Ages & ... permit escape. If you live in an apartment building, never use an elevator during a fire. Use ...

  5. Comparative visual analysis of 3D urban wind simulations

    Science.gov (United States)

    Röber, Niklas; Salim, Mohamed; Grawe, David; Leitl, Bernd; Böttinger, Michael; Schlünzen, Heinke

    2016-04-01

    Climate simulations are conducted in large quantity for a variety of different applications. Many of these simulations focus on global developments and study the Earth's climate system using a coupled atmosphere ocean model. Other simulations are performed on much smaller regional scales, to study very small fine grained climatic effects. These microscale climate simulations pose similar, yet also different, challenges for the visualization and the analysis of the simulation data. Modern interactive visualization and data analysis techniques are very powerful tools to assist the researcher in answering and communicating complex research questions. This presentation discusses comparative visualization for several different wind simulations, which were created using the microscale climate model MITRAS. The simulations differ in wind direction and speed, but are all centered on the same simulation domain: An area of Hamburg-Wilhelmsburg that hosted the IGA/IBA exhibition in 2013. The experiments contain a scenario case to analyze the effects of single buildings, as well as examine the impact of the Coriolis force within the simulation. The scenario case is additionally compared with real measurements from a wind tunnel experiment to ascertain the accuracy of the simulation and the model itself. We also compare different approaches for tree modeling and evaluate the stability of the model. In this presentation, we describe not only our workflow to efficiently and effectively visualize microscale climate simulation data using common 3D visualization and data analysis techniques, but also discuss how to compare variations of a simulation and how to highlight the subtle differences in between them. For the visualizations we use a range of different 3D tools that feature techniques for statistical data analysis, data selection, as well as linking and brushing.

  6. Modeling mechanisms of vegetation change due to fire in a semi-arid ecosystem

    Science.gov (United States)

    White, J.D.; Gutzwiller, K.J.; Barrow, W.C.; Randall, L.J.; Swint, P.

    2008-01-01

    Vegetation growth and community composition in semi-arid environments is determined by water availability and carbon assimilation mechanisms specific to different plant types. Disturbance also impacts vegetation productivity and composition dependent on area affected, intensity, and frequency factors. In this study, a new spatially explicit ecosystem model is presented for the purpose of simulating vegetation cover type changes associated with fire disturbance in the northern Chihuahuan Desert region. The model is called the Landscape and Fire Simulator (LAFS) and represents physiological activity of six functional plant types incorporating site climate, fire, and seed dispersal routines for individual grid cells. We applied this model for Big Bend National Park, Texas, by assessing the impact of wildfire on the trajectory of vegetation communities over time. The model was initialized and calibrated based on landcover maps derived from Landsat-5 Thematic Mapper data acquired in 1986 and 1999 coupled with plant biomass measurements collected in the field during 2000. Initial vegetation cover change analysis from satellite data showed shrub encroachment during this time period that was captured in the simulated results. A synthetic 50-year climate record was derived from historical meteorological data to assess system response based on initial landcover conditions. This simulation showed that shrublands increased to the detriment of grass and yucca-ocotillo vegetation cover types indicating an ecosystem-level trajectory for shrub encroachment. Our analysis of simulated fires also showed that fires significantly reduced site biomass components including leaf area, stem, and seed biomass in this semi-arid ecosystem. In contrast to other landscape simulation models, this new model incorporates detailed physiological responses of functional plant types that will allow us to simulated the impact of increased atmospheric CO2 occurring with climate change coupled with fire

  7. The simulation study of three typical time frequency analysis methods

    Directory of Open Access Journals (Sweden)

    Li Yifeng

    2017-01-01

    Full Text Available The principals and characteristics of three typical time frequency analysis methods that Short Time Furious transformation, wavelet transformation and Hilbert-Huang transformation are introduced, and the mathematical definition, characteristics and application ranges of these analysis methods and so on are pointed out, then their time-frequency local performance is made analysis and comparison through computer programming and simulation.

  8. Laboratory investigation of photochemical oxidation of organic aerosol from wood fires 1: measurement and simulation of organic aerosol evolution

    Directory of Open Access Journals (Sweden)

    A. P. Grieshop

    2009-02-01

    Full Text Available Experiments were conducted to investigate the effects of photo-oxidation on organic aerosol (OA emissions from flaming and smoldering hard- and soft-wood fires under plume-like conditions. This was done by exposing the dilute emissions from a small wood stove to UV light in a smog chamber and measuring the gas- and particle-phase pollutant concentrations with a suite of instruments including a Proton Transfer Reaction Mass Spectrometer (PTR-MS, an Aerosol Mass Spectrometer (AMS and a thermodenuder. The measurements highlight how atmospheric processing can lead to considerable evolution of the mass and volatility of biomass-burning OA. Photochemical oxidation produced substantial new OA, increasing concentrations by a factor of 1.5 to 2.8 after several hours of exposure to typical summertime hydroxyl radical (OH concentrations. Less than 20% of this new OA could be explained using a state-of-the-art secondary organic aerosol model and the measured decay of traditional SOA precursors. The thermodenuder data indicate that the primary OA is semivolatile; at 50°C between 50 and 80% of the fresh primary OA evaporated. Aging reduced the volatility of the OA; at 50°C only 20 to 40% of aged OA evaporated. The predictions of a volatility basis-set model that explicitly tracks the partitioning and aging of low-volatility organics was compared to the chamber data. The OA production can be explained by the oxidation of low-volatility organic vapors; the model can also reproduce observed changes in OA volatility and composition. The model was used to investigate the competition between photochemical processing and dilution on OA concentrations in plumes.

  9. Numerical simulation on fire hazard of large commercial crude oil reserve depot%大型原油商业储备油库火灾危险性数值模拟分析

    Institute of Scientific and Technical Information of China (English)

    贠璞

    2013-01-01

    石油储备油库多向大型化、复杂化方向发展,发生事故时扑救非常困难。为了深入探讨巨型油罐火灾发展趋势与规律、事故危害后果,结合宁夏惠安堡原油商业储备油库这一工程实例,采用基于大涡模拟的FDS模型作为模拟计算平台,对巨型油罐火灾的燃烧过程进行数值模拟计算。通过分析计算,得到烟气分布、温度分布、热辐射强度分布等火灾过程参数的变化趋势,以及在有风和无风状态下着火罐对相邻油罐的影响,探讨现行建设工程消防技术标准就储罐防火间距、火灾时对邻近罐体冷却设计要求运用于巨型储油罐时的消防安全状况,为巨型储油罐消防安全科学合理设计提供理论依据。%The crude oil reserve depot is tending to be large and complex , and the fire fighting is quite difficult .In order to deeply discuss the development trend , principles and consequence of fire accident for huge oil storage tank , combi-ning with the practical engineering case of Huianpu commercial crude oil reserve depot in Ningxia , by applying FDS model based on large eddy simulation as calculation platform , the numerical simulation on combustion process of huge oil storage tank fire was performed .The change trends of fire process parameters , such as smoke distribution , temperature distribution and thermal radiation intensity , were obtained , as well as the influence of flaming tank on adjacent tanks under windy and windless conditions .The fire protection safety status when applying the design re-quirements in the existing technical standards on fire control of construction engineering , such as fire separation dis-tance of tank and cooling adjacent tanks during fire process , on the huge oil storage tank was discussed , which can provide theoretical foundation to the scientific and reasonable design on fire protection safety of huge oil storage tank .

  10. Simulation Approach to Mission Risk and Reliability Analysis Project

    Data.gov (United States)

    National Aeronautics and Space Administration — It is proposed to develop and demonstrate an integrated total-system risk and reliability analysis approach that is based on dynamic, probabilistic simulation. This...

  11. THE COMBUSTION CHARACTERISTICS OF A MOVABLE LINEAR FIRE SEAT IN MINE FIRES

    Institute of Scientific and Technical Information of China (English)

    王德明; 王省身

    1996-01-01

    Because of the difficulties of describing the process of combustion of underground mine fires, usually the fire seat is considered as a fixed point in the methods of mine fire computer simulation, however this is not in keeping with the feature of the distribution of the combustibles and the process of combustion in mine fires. A conception about movable linear fire seat is put forward first by the authors, together with the calculated models of the thermal decomposition rate, flame spreading velocity and the steady burning length of a linear fire seat etc. The paper also introduces the results of the application of these models.

  12. A Multi-Code Analysis Toolkit for Astrophysical Simulation Data

    OpenAIRE

    Turk, Matthew J.; Smith., Britton D.; Oishi, Jeffrey S.; Skory, Stephen; Skillman, Samuel W.; Abel, Tom; Norman, Michael L.

    2010-01-01

    The analysis of complex multiphysics astrophysical simulations presents a unique and rapidly growing set of challenges: reproducibility, parallelization, and vast increases in data size and complexity chief among them. In order to meet these challenges, and in order to open up new avenues for collaboration between users of multiple simulation platforms, we present yt (available at http://yt.enzotools.org/), an open source, community-developed astrophysical analysis and visualization toolkit. ...

  13. A convective and radiative heat transfer analysis for the FIRE II forebody

    Science.gov (United States)

    Greendyke, Robert B.; Hartung, Lin C.

    1993-01-01

    A Navier-Stokes flowfield solution method (LAURA code) using finite-rate chemistry and two-temperature thermal nonequilibrium was used in combination with two nonequilibrium radiative heat transfer codes to calculate heating for the FIRE II vehicle. An axisymmetric model of the actual body shape was used. One radiative heating code (NEQAIR) was used in uncoupled fashion with the flowfield solver's energy equations, while the other code (LORAN) was used in both coupled and uncoupled variations. Several trajectory points ranging from highly nonequilibrium flow to near-equilibrium flow were used for a study of both convective and radiative heating over the vehicle. Considerable variation in radiative heating was seen at the extremes, while agreement was good in the intermediate trajectory points. Total heat transfer calculations gave good comparison until the peak heating trajectory points were encountered, and returned to good agreement for the last two equilibrium points.

  14. Time series analysis of fine particulate matter and asthma reliever dispensations in populations affected by forest fires

    Directory of Open Access Journals (Sweden)

    Elliott Catherine T

    2013-01-01

    Full Text Available Abstract Background Several studies have evaluated the association between forest fire smoke and acute exacerbations of respiratory diseases, but few have examined effects on pharmaceutical dispensations. We examine the associations between daily fine particulate matter (PM2.5 and pharmaceutical dispensations for salbutamol in forest fire-affected and non-fire-affected populations in British Columbia (BC, Canada. Methods We estimated PM2.5 exposure for populations in administrative health areas using measurements from central monitors. Remote sensing data on fires were used to classify the populations as fire-affected or non-fire-affected, and to identify extreme fire days. Daily counts of salbutamol dispensations between 2003 and 2010 were extracted from the BC PharmaNet database. We estimated rate ratios (RR and 95% confidence intervals (CIs for each population during all fire seasons and on extreme fire days, adjusted for temperature, humidity, and temporal trends. Overall effects for fire-affected and non-fire-affected populations were estimated via meta-regression. Results Fire season PM2.5 was positively associated with salbutamol dispensations in all fire-affected populations, with a meta-regression RR (95% CI of 1.06 (1.04-1.07 for a 10 ug/m3 increase. Fire season PM2.5 was not significantly associated with salbutamol dispensations in non-fire-affected populations, with a meta-regression RR of 1.00 (0.98-1.01. On extreme fire days PM2.5 was positively associated with salbutamol dispensations in both population types, with a global meta-regression RR of 1.07 (1.04 - 1.09. Conclusions Salbutamol dispensations were clearly associated with fire-related PM2.5. Significant associations were observed in smaller populations (range: 8,000 to 170,000 persons, median: 26,000 than those reported previously, suggesting that salbutamol dispensations may be a valuable outcome for public health surveillance during fire events.

  15. ORSA: Orbit Reconstruction, Simulation and Analysis

    Science.gov (United States)

    Tricarico, Pasquale

    2012-04-01

    ORSA is an interactive tool for scientific grade Celestial Mechanics computations. Asteroids, comets, artificial satellites, solar and extra-solar planetary systems can be accurately reproduced, simulated, and analyzed. The software uses JPL ephemeris files for accurate planets positions and has a Qt-based graphical user interface. It offers an advanced 2D plotting tool and 3D OpenGL viewer and the standalone numerical library liborsa and can import asteroids and comets from all the known databases (MPC, JPL, Lowell, AstDyS, and NEODyS). In addition, it has an integrated download tool to update databases.

  16. Simulation Analysis of Indoor Gas Explosion Damage

    Institute of Scientific and Technical Information of China (English)

    钱新明; 陈林顺; 冯长根

    2003-01-01

    The influence factors and process of indoor gas explosion are studied with AutoReaGas explosion simulator. The result shows that venting pressure has great influence on the indoor gas explosion damage. The higher the venting pressure is, the more serious the hazard consequence will be. The ignition location has also evident effect on the gas explosion damage. The explosion static overpressure would not cause major injury to person and serious damage to structure in the case of low venting pressure (lower than 2 kPa). The high temperature combustion after the explosion is the major factor to person injury in indoor gas explosion accidents.

  17. Detection and Characterization of Low Temperature Peat Fires during the 2015 Fire Catastrophe in Indonesia Using a New High-Sensitivity Fire Monitoring Satellite Sensor (FireBird)

    Science.gov (United States)

    Atwood, Elizabeth C.; Englhart, Sandra; Lorenz, Eckehard; Halle, Winfried; Wiedemann, Werner; Siegert, Florian

    2016-01-01

    Vast and disastrous fires occurred on Borneo during the 2015 dry season, pushing Indonesia into the top five carbon emitting countries. The region was affected by a very strong El Niño-Southern Oscillation (ENSO) climate phenomenon, on par with the last severe event in 1997/98. Fire dynamics in Central Kalimantan were investigated using an innovative sensor offering higher sensitivity to a wider range of fire intensities at a finer spatial resolution (160 m) than heretofore available. The sensor is onboard the TET-1 satellite, part of the German Aerospace Center (DLR) FireBird mission. TET-1 images (acquired every 2–3 days) from the middle infrared were used to detect fires continuously burning for almost three weeks in the protected peatlands of Sebangau National Park as well as surrounding areas with active logging and oil palm concessions. TET-1 detection capabilities were compared with MODIS active fire detection and Landsat burned area algorithms. Fire dynamics, including fire front propagation speed and area burned, were investigated. We show that TET-1 has improved detection capabilities over MODIS in monitoring low-intensity peatland fire fronts through thick smoke and haze. Analysis of fire dynamics revealed that the largest burned areas resulted from fire front lines started from multiple locations, and the highest propagation speeds were in excess of 500 m/day (all over peat > 2m deep). Fires were found to occur most often in concessions that contained drainage infrastructure but were not cleared prior to the fire season. Benefits of implementing this sensor system to improve current fire management techniques are discussed. Near real-time fire detection together with enhanced fire behavior monitoring capabilities would not only improve firefighting efforts, but also benefit analysis of fire impact on tropical peatlands, greenhouse gas emission estimations as well as mitigation measures to reduce severe fire events in the future. PMID:27486664

  18. Detection and Characterization of Low Temperature Peat Fires during the 2015 Fire Catastrophe in Indonesia Using a New High-Sensitivity Fire Monitoring Satellite Sensor (FireBird).

    Science.gov (United States)

    Atwood, Elizabeth C; Englhart, Sandra; Lorenz, Eckehard; Halle, Winfried; Wiedemann, Werner; Siegert, Florian

    2016-01-01

    Vast and disastrous fires occurred on Borneo during the 2015 dry season, pushing Indonesia into the top five carbon emitting countries. The region was affected by a very strong El Niño-Southern Oscillation (ENSO) climate phenomenon, on par with the last severe event in 1997/98. Fire dynamics in Central Kalimantan were investigated using an innovative sensor offering higher sensitivity to a wider range of fire intensities at a finer spatial resolution (160 m) than heretofore available. The sensor is onboard the TET-1 satellite, part of the German Aerospace Center (DLR) FireBird mission. TET-1 images (acquired every 2-3 days) from the middle infrared were used to detect fires continuously burning for almost three weeks in the protected peatlands of Sebangau National Park as well as surrounding areas with active logging and oil palm concessions. TET-1 detection capabilities were compared with MODIS active fire detection and Landsat burned area algorithms. Fire dynamics, including fire front propagation speed and area burned, were investigated. We show that TET-1 has improved detection capabilities over MODIS in monitoring low-intensity peatland fire fronts through thick smoke and haze. Analysis of fire dynamics revealed that the largest burned areas resulted from fire front lines started from multiple locations, and the highest propagation speeds were in excess of 500 m/day (all over peat > 2m deep). Fires were found to occur most often in concessions that contained drainage infrastructure but were not cleared prior to the fire season. Benefits of implementing this sensor system to improve current fire management techniques are discussed. Near real-time fire detection together with enhanced fire behavior monitoring capabilities would not only improve firefighting efforts, but also benefit analysis of fire impact on tropical peatlands, greenhouse gas emission estimations as well as mitigation measures to reduce severe fire events in the future.

  19. Sleep Now in the Fire: An Analysis of A Song By Rage Against the Machine using Marxism

    Directory of Open Access Journals (Sweden)

    Abdul Aziz Turhan Kariko

    2011-09-01

    Full Text Available Rage against the Machine is known for their politics as well as their music, which the later helped creating an aggressive-heavy rock-rap genre. Article presents a song by Rage against the Machine band related to ideological movement in America, titled Sleep Now in the Fire. This effort brings an understanding of ideology that is embraced by the band. The method is through literature study. Presentation begins with a short biography of the band, theoretical concepts, and analysis of the song as well its music video. It is concluded that the song represents ideological criticism toward capitalism using Marxism. Both of these lyric and music video represents Marxism as it shares the same movement to fight capitalism which in this case, Rage against the Machine is using their music, lyric, and video to fight the crime against humanity and cultural imperialism.

  20. Simulation of valveless micropump and mode analysis

    CERN Document Server

    Lan, W P; Wu, K C; Shih, Y C

    2008-01-01

    In this work, a 3-D simulation is performed to study for the solid-fluid coupling effect driven by piezoelectric materials and utilizes asymmetric obstacles to control the flow direction. The result of simulation is also verified. For a micropump, it is crucial to find the optimal working frequency which produce maximum net flow rate. The PZT plate vibrates under the first mode, which is symmetric. Adjusting the working frequency, the maximum flow rate can be obtained. For the micrpump we studied, the optimal working frequency is 3.2K Hz. At higher working frequency, say 20K Hz, the fluid-solid membrane may come out a intermediate mode, which is different from the first mode and the second mode. It is observed that the center of the mode drifts. Meanwhile, the result shows that a phase shift lagging when the excitation force exists in the vibration response. Finally, at even higher working frequency, say 30K Hz, a second vibration mode is observed.

  1. Firing statistics and correlations in spiking neurons: a level-crossing approach.

    Science.gov (United States)

    Badel, Laurent

    2011-10-01

    We present a time-dependent level-crossing theory for linear dynamical systems perturbed by colored Gaussian noise. We apply these results to approximate the firing statistics of conductance-based integrate-and-fire neurons receiving excitatory and inhibitory Poissonian inputs. Analytical expressions are obtained for three key quantities characterizing the neuronal response to time-varying inputs: the mean firing rate, the linear response to sinusoidally modulated inputs, and the pairwise spike correlation for neurons receiving correlated inputs. The theory yields tractable results that are shown to accurately match numerical simulations and provides useful tools for the analysis of interconnected neuronal populations.

  2. Experimental Study on Airflow Reversal Within Bypass Branch During Mine Fire

    Institute of Scientific and Technical Information of China (English)

    周福宝; 王德明; 周延

    2001-01-01

    Based on the analysis of conditions for airflow reversal within a bypass branch, the airflow reversal phenomena were successfully simulated in the laboratory experiments. Data obtained indicate that airflow reversal within a bypass branch is mainly caused by fire pressure yielded in the combustion branch. In addition, the maximum reversal quantity of airflow occurs in step with the highest temperature of fire, the highest concentration of CO2 and the lowest concentration of O2. Moreover, the time that fire size reaches the maximum value corresponds to the time airflow reversal in the bypass branch is most possible. The results are of great significance for guiding rescue work to avoid airflow reversal.

  3. 燃煤锅炉改造为燃气锅炉技术经济分析%Technical and Economic Analysis of Transforming Coal-Fired Boiler to Gas-Fired Boiler

    Institute of Scientific and Technical Information of China (English)

    万捷文

    2014-01-01

    To solve the contradiction of energy supply/demand and environmental pollution, the technology of transforming coal-fired boiler to gas-fired boiler has been discussed recently, and demonstrated by the technical and economic analysis combining with the engineering case. It points out that by choosing the alternative reasonably, the gas-fired Boiler is the main method of transforming coal-fired boiler, and it can meet the profits, environmental protection policy and energy policy as well.%伴随能源供需和环境污染的矛盾日益突出,在用燃煤锅炉进行天然气替代改造问题,引起管理部门和专家学者的关注,并进行了有益的研究。通过对燃煤锅炉的燃气替代中不同方案的技术经济分析,并结合工程实践,论证了燃煤锅炉天然气替代的经济性和可行性。结论表明,通过合理选择替代方案和工程实施,天然气锅炉能符合企业经济利益和社会环保政策、能源政策的发展趋势,是目前锅炉建设及改造的主要方向。

  4. Uncertainty and risk in wildland fire management: a review.

    Science.gov (United States)

    Thompson, Matthew P; Calkin, Dave E

    2011-08-01

    Wildland fire management is subject to manifold sources of uncertainty. Beyond the unpredictability of wildfire behavior, uncertainty stems from inaccurate/missing data, limited resource value measures to guide prioritization across fires and resources at risk, and an incomplete scientific understanding of ecological response to fire, of fire behavior response to treatments, and of spatiotemporal dynamics involving disturbance regimes and climate change. This work attempts to systematically align sources of uncertainty with the most appropriate decision support methodologies, in order to facilitate cost-effective, risk-based wildfire planning efforts. We review the state of wildfire risk assessment and management, with a specific focus on uncertainties challenging implementation of integrated risk assessments that consider a suite of human and ecological values. Recent advances in wildfire simulation and geospatial mapping of highly valued resources have enabled robust risk-based analyses to inform planning across a variety of scales, although improvements are needed in fire behavior and ignition occurrence models. A key remaining challenge is a better characterization of non-market resources at risk, both in terms of their response to fire and how society values those resources. Our findings echo earlier literature identifying wildfire effects analysis and value uncertainty as the primary challenges to integrated wildfire risk assessment and wildfire management. We stress the importance of identifying and characterizing uncertainties in order to better quantify and manage them. Leveraging the most appropriate decision support tools can facilitate wildfire risk assessm