Firefighter Safety Zones: A Theoretical Model Based on Radiative Heating

1998 ◽  
Vol 8 (2) ◽  
pp. 73 ◽  
Author(s):  
BW Butler ◽  
JD Cohen
Keyword(s):  
Theoretical Model ◽  
Radiant Energy ◽  
General Rule ◽  
Quantitative Information ◽  
Radiative Heating ◽  
Flame Height ◽  
Safety Zone ◽  
Model Predictions ◽  
Zone Radius ◽  
Height Model

Quantitative information regarding safety zone size for wildland firefighters is limited. We present a 3-surface theoretical model that describes the net radiant energy transfer to a firefighter standing a specified distance from a fire of specified height. Model predictions compare favorably with qualitative data from entrapments on four wildfires and two previously published models. Calculations indicate that for most fires, safety zones must be greater than 20 m wide to ensure firefighter survival. A general rule-of-thumb derived from this work is that a safety zone radius must be equal to or greater than 4 times the maximum flame height.

Radiative Heating in Ice

1977 ◽  
Vol 99 (2) ◽  
pp. 227-232 ◽  
Author(s):  
R. R. Gilpin ◽  
R. B. Robertson ◽  
B. Singh
Keyword(s):  
Theoretical Model ◽  
Spectral Dependence ◽  
Radiant Energy ◽  
Incident Radiation ◽  
Anisotropic Scattering ◽  
Radiative Heating ◽  
Energy Sources ◽  
Laboratory Measurements ◽  
Radiation Beam ◽  
Collimated Beam

The energy fluxes that exist in an ice sheet exposed to a collimated beam of radiant energy were examined. A theoretical model was used which includes the effects of anisotropic scattering as well as the spectral dependence of the absorption coefficient of ice and of the incident radiation beam. Laboratory measurements were also made which generally confirm the predictions of the model. The results calculated from the model are primarily intended for use in analyzing two particular problems involving radiative transfer in ice. These are: (a) the assessment of the feasibility of using radiant energy sources as a means of removing ice from structures, and (b) the prediction of temperatures and internal melting in ice covers on lakes and rivers due to the absorption of solar radiation.

Radiation-Induced Buoyancy-Driven Flow in Rectangular Enclosures: Experiment and Analysis

1987 ◽  
Vol 109 (2) ◽  
pp. 427-433 ◽  
Author(s):  
B. W. Webb ◽  
R. Viskanta
Keyword(s):  
Experimental Data ◽  
Temperature Field ◽  
Theoretical Model ◽  
Radiation Flux ◽  
Convective Motion ◽  
Radiative Heating ◽  
Working Fluid ◽  
Injection Technique ◽  
Flux Divergence ◽  
Radiation Induced

Experiments have been performed to study the rate of internal radiative heating on the natural convective motion in a vertical rectangular enclosure irradiated from the side. A Mach–Zehnder interferometer has been used to determine the temperature field, and a fluorescing dye injection technique was employed to illustrate the flow structure with water as the working fluid. A theoretical model is developed for predicting the absorption of thermal radiation and the subsequent buoyancy-driven flow. Predictions based on spectral calculations for the radiation flux divergence agree well with the experimental data.

Hydraulic Driven Rotating Flexible Beam: Theoretical Modal Analysis and Proportional Servo Drive Parameter Influence

2003 ◽  
Author(s):  
Javier Freire ◽  
Esteve Codina ◽  
Munir Khamashta
Keyword(s):  
Theoretical Model ◽  
Modal Analysis ◽  
Dynamic Performance ◽  
Normal Modes ◽  
Flexible Beam ◽  
Servo Drive ◽  
Analysis Methodology ◽  
Model Predictions ◽  
Hydraulic Servo ◽  
Machine Elements

Understanding the behavior of system with flexible elements is increasingly important in modern day technology. Reducing the mass of machine elements leads to a remarkable improvement in dynamic performance. However, a loss of precision also occurs with such an increase in flexibility. In order to arrive at a better understanding of systems with flexible elements, we are investigating the particular behavior of a hydraulic servo driven rotating flexible beam with the aim of obtaining a methodology that could be applied to a real application. To investigate this behavior, a set of models has been developed. In this paper, a theoretical model, using classical modal analysis methodology, is presented. The flexible beam is modeled in a standard way and the hydraulic servo drive is modeled as a boundary condition. Only normal modes will be investigated. This approach allows considering the servo proportional constant and the cylinder mass. It will be show that the servo proportional constant has low influence in the system eigen frequencies. The theoretical model predictions are validated experimentally.

Back-Melting of a Horizontal Cloudy Ice Layer with Radiative Heating

1979 ◽  
Vol 101 (1) ◽  
pp. 90-95 ◽  
Author(s):  
N. Seki ◽  
M. Sugawara ◽  
S. Fukusako
Keyword(s):  
Radiant Energy ◽  
Short Wave ◽  
Melting Rate ◽  
Radiative Heating ◽  
Wave Radiation ◽  
Band Model ◽  
Air Bubbles ◽  
Short Wave Radiation ◽  
Radiation Sources ◽  
Infrared Spectral

This paper is concerned with the melting of a horizontal ice layer sticking to a substrate by using halogen lamps, which are comparatively short wave radiation sources. This radiation in the visible and infrared spectral range may be employed to remove ice from structures subject to atmospheric icing. It is concluded that the behavior of radiation transfer in a cloudy ice layer depends a great deal on the density of the cloudy ice including air bubbles which produce the scattering of radiation. Also the phenomenon of back-melting caused by radiant energy penetrating through the ice layer is observed. Moreover, it is shown that the melting rate of an ice layer can be predicted numerically by using the band model of extinction coefficient for cloudy ice assumed in this study.

scholarly journals An empirically based approach to defining wildland firefighter safety and survival zone separation distances

2017 ◽  
Vol 26 (8) ◽  
pp. 655 ◽  
Author(s):  
Wesley G. Page ◽  
Bret W. Butler
Keyword(s):  
Burn Injury ◽  
Empirical Models ◽  
Flame Height ◽  
Fuel Type ◽  
Safety Zone ◽  
Fatal Injury ◽  
Firefighter Safety ◽  
Injury Model ◽  
The Us ◽  
Low Probability

Wildland firefighters in the US are mandated to identify areas that provide adequate separation between themselves and the flames (i.e. safety zones) to reduce the risk of burn injury. This study presents empirical models that estimate the distance from flames that would result in a low probability (1 or 5%) of either fatal or non-fatal injuries. The significant variables for the fatal injury model were fire shelter use, slope steepness and flame height. The separation distances needed to ensure no more than a 1 or 5% probability of fatal injury, without the use of a fire shelter, for slopes less than 25% were 20 to 50 m for flame heights less than 10 m, and 1 to 4 times the flame height for flames taller than 10 m. The non-fatal injury model significant variables were fire shelter use, vehicle use and fuel type. At the 1 and 5% probability thresholds for a non-fatal injury, without the use of a fire shelter, the separation distances were 1 to 2, 6 to 7, and 12 to 16 times greater than the current safety zone guideline (i.e. 4 times the flame height) for timber, brush and grass fuel types respectively.

Effects of Aging on Polymerization Kinetics

1990 ◽  
Vol 215 ◽  
Author(s):  
Christopher N. Bowman ◽  
Nikolaos A. Peppas
Keyword(s):  
Relaxation Time ◽  
Theoretical Model ◽  
Light Intensity ◽  
Physical Aging ◽  
Volume Relaxation ◽  
Radical Concentration ◽  
Model Predictions ◽  
Maximum Conversion ◽  
Effects Of Aging ◽  
Crosslinking Reactions

AbstractA theoretical model was developed to describe the physical aging during photopolymerizations and crosslinking reactions of diacrylates and dimethacrylates. The model incorporates the strong coupling between the volume relaxation and the kinetics observed in these reactions. Model predictions are presented for the reaction kinetics, volume relaxation, radical concentration and maximum conversion as a function of light intensity and relaxation time of the polymer.

CW and temporal theoretical model predictions and experimental results for Tm:YAG and Ho:YAG lasers

2008 ◽  
Author(s):  
Eric K. Gorton ◽  
John G. Betterton ◽  
David A. Orchard ◽  
Brian J. Perrett ◽  
Paul D. Mason ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Experimental Results ◽  
Model Predictions

scholarly journals Coupling Reduces Noise: Applying Dynamical Coupling to Reduce Local White Additive Noise

2015 ◽  
Vol 25 (03) ◽  
pp. 1550040 ◽  
Author(s):  
Behnam Kia ◽  
Sarvenaz Kia ◽  
John F. Lindner ◽  
Sudeshna Sinha ◽  
William L. Ditto
Keyword(s):  
Theoretical Model ◽  
Dynamical Systems ◽  
Noise Level ◽  
Additive Noise ◽  
Nonlinear Dynamical Systems ◽  
Coupled Map Lattices ◽  
Nonlinear Dynamical ◽  
Model Predictions ◽  
Dynamical Coupling ◽  
Averaging Filter

We demonstrate how coupling nonlinear dynamical systems can reduce the effects of noise. For simplicity we investigate noisy coupled map lattices and assume noise is white and additive. Noise from different lattice nodes can diffuse across the lattice and lower the noise level of individual nodes. We develop a theoretical model that explains this observed noise evolution and show how the coupled dynamics can naturally function as an averaging filter. Our numerical simulations are in excellent agreement with the model predictions.

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