Angular variation of fire rate of spread

2013 ◽  
Vol 22 (7) ◽  
pp. 970 ◽  
Author(s):  
Jorge C. S. André ◽  
João C. Gonçalves ◽  
Gilberto C. Vaz ◽  
Domingos X. Viegas
Keyword(s):  
Indirect Method ◽  
Direct Method ◽  
Slope Angle ◽  
Infrared Camera ◽  
Ambient Conditions ◽  
Rate Of Spread ◽  
Orientation Function ◽  
Fire Front ◽  
Closed Line ◽  
The Given

Laboratory fire tests were performed in still air, for variable inclinations (10°, 15°) and fuel bed dimensions (1.28×2.50–3.0×4.6m2), with homogeneous fuel beds of pine needles and pine wood excelsior. The fire ignition was made at a point, along a closed line with no fuel inside and along a straight edge of the fuel bed. The tests were recorded with an infrared camera and various techniques were developed to implement direct and indirect empirical methods of construction of the ‘orientation function’ of the fire in the given fuel bed and ambient conditions, showing how the rate of spread of a steady straight fire front depends on its orientation on the terrain. The direct method uses a set of straight fire fronts with various orientations whereas the indirect method uses essentially a point ignited fire front. Contrary to what is assumed in BehavePlus model, the orientation function is observed to depend significantly on the properties of the fuel bed. In all tests with closed fire fronts, the full steadiness required by the indirect method was not achieved (namely, at the head of the front), although, for slope angle of 10°, the corresponding errors induced on the orientation function were small.

Quasi-Periodic Control Technique for Minimizing Fuel Consumption During Record Vehicle Competition

2013 ◽  
Vol 60 (2) ◽  
pp. 185-197 ◽  
Author(s):  
Paweł Sulikowski ◽  
Ryszard Maronski
Keyword(s):  
Fuel Consumption ◽  
Optimal Control Theory ◽  
Slope Angle ◽  
Control Technique ◽  
Decision Variables ◽  
Aeronautical Engineering ◽  
The One ◽  
Optimal Driving ◽  
The Given ◽  
Engine Power

The problem of the optimal driving technique during the fuel economy competition is reconsidered. The vehicle is regarded as a particle moving on a trace with a variable slope angle. The fuel consumption is minimized as the vehicle covers the given distance in a given time. It is assumed that the run consists of two recurrent phases: acceleration with a full available engine power and coasting down with the engine turned off. The most fuel-efficient technique for shifting gears during acceleration is found. The decision variables are: the vehicle velocities at which the gears should be shifted, on the one hand, and the vehicle velocities when the engine should be turned on and off, on the other hand. For the data of students’ vehicle representing the Faculty of Power and Aeronautical Engineering it has been found that such driving strategy is more effective in comparison with a constant speed strategy with the engine partly throttled, as well as a strategy resulting from optimal control theory when the engine is still active.

scholarly journals Development of a Field Deployable Firebrand Flux and Condition Measurement System

2020 ◽  
Author(s):  
Simone Zen ◽  
Jan C. Thomas ◽  
Eric V. Mueller ◽  
Bhisham Dhurandher ◽  
Michael Gallagher ◽  
...  
Keyword(s):  
Imaging Techniques ◽  
Time History ◽  
Infrared Camera ◽  
Thermal Conditions ◽  
Particle Characterization ◽  
Fire Dynamics ◽  
Rate Of Spread ◽  
New Instrument ◽  
History Of

AbstractA new instrument to quantify firebrand dynamics during fires with particular focus on those associated with the Wildland-Urban Interface (WUI) has been developed. During WUI fires, firebrands can ignite spot fires, which can rapidly increase the rate of spread (ROS) of the fire, provide a mechanism by which the fire can pass over firebreaks and are the leading cause of structure ignitions. Despite this key role in driving wildfire dynamics and hazards, difficulties in collecting firebrands in the field and preserving their physical condition (e.g. dimensions and temperature) have limited the development of knowledge of firebrand dynamics. In this work we present a new, field-deployable diagnostic tool, an emberometer, designed to provide measurement of firebrand fluxes and information on both the geometry and the thermal conditions of firebrands immediately before deposition by combining a visual and infrared camera. A series of laboratory experiments were conducted to calibrate and validate the developed imaging techniques. The emberometer was then deployed in the field to explore firebrand fluxes and particle conditions for a range of fire intensities in natural pine forest environments. In addition to firebrand particle characterization, field observations with the emberometer enabled detailed time history of deposition (i.e. firebrand flux) relative to concurrent in situ fire behaviour observations. We highlight that deposition was characterised by intense, short duration “showers” that can be reasonably associated to spikes in the average fire line intensity. The results presented illustrate the potential use of an emberometer in studying firebrand and spot fire dynamics.

Fine-Scale Fire Spread in Pine Straw

Fire ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 69
Author(s):  
Daryn Sagel ◽  
Kevin Speer ◽  
Scott Pokswinski ◽  
Bryan Quaife
Keyword(s):  
Fire Spread ◽  
Small Scale ◽  
Natural Setting ◽  
Fine Scale ◽  
Prescribed Burn ◽  
Fire Dynamics ◽  
Rate Of Spread ◽  
Scale Models ◽  
Fire Front ◽  
Visible Images

Most wildland and prescribed fire spread occurs through ground fuels, and the rate of spread (RoS) in such environments is often summarized with empirical models that assume uniform environmental conditions and produce a unique RoS. On the other hand, representing the effects of local, small-scale variations of fuel and wind experienced in the field is challenging and, for landscape-scale models, impractical. Moreover, the level of uncertainty associated with characterizing RoS and flame dynamics in the presence of turbulent flow demonstrates the need for further understanding of fire dynamics at small scales in realistic settings. This work describes adapted computer vision techniques used to form fine-scale measurements of the spatially and temporally varying RoS in a natural setting. These algorithms are applied to infrared and visible images of a small-scale prescribed burn of a quasi-homogeneous pine needle bed under stationary wind conditions. A large number of distinct fire front displacements are then used statistically to analyze the fire spread. We find that the fine-scale forward RoS is characterized by an exponential distribution, suggesting a model for fire spread as a random process at this scale.

scholarly journals The Preference of Direct or Indirect Methods in Preparing the Statement of Cash Flows in Decision Making: An Academic Perspective

2016 ◽  
Vol 8 (2) ◽  
pp. 206
Author(s):  
Abdullah, S. Hardan ◽  
Majed, A. Qabajeh ◽  
Aymen, M. Alshanti
Keyword(s):  
Decision Making ◽  
Indirect Method ◽  
Direct Method ◽  
Cash Flows ◽  
Decision Makers ◽  
Academic Rank ◽  
Indirect Methods ◽  
Statement Of Cash Flows ◽  
Qualitative Characteristics ◽  
Academic Sector

Two methods are used when reporting cash flows from operating activities: the direct method or the indirect method, both are acceptable from IAS with a preference of direct method. Thus, this paper examines which method of reporting the statement of cash flows provides useful information the decision makers rely on for decision making purposes. To achieve this aim, participants were selected from academic sector represented by universities professors. The study is based on the conceptual framework: qualitative characteristics of accounting information. To be useful, information must be relevant and represents faithfully what it claims to represent. In order to distinguish more useful financial information from those less useful, enhancing qualitative characteristics were examined. Results show that academic professors provide support for direct method of reporting cash flows over indirect method. The study sought to determine the effect of academic rank on these results. Evidence reveals that full and associate professors endorsed the preference of direct method more than assistant professors and lecturers. These results recommend the legislative bodies and entities to adopt the direct method in preparation the statement of cash flows.

scholarly journals Теплоемкость и магнитокалорический эффект соединений LaFe-=SUB=-11.2-x-=/SUB=-Mn-=SUB=-x-=/SUB=-Co-=SUB=-0.7-=/SUB=-Si-=SUB=-1.1-=/SUB=- (x=0, 0.1, 0.2, 0.3)

2020 ◽  
Vol 62 (5) ◽  
pp. 752
Author(s):  
Н.З. Абдулкадирова ◽  
А.М. Алиев ◽  
А.Г. Гамзатов ◽  
P. Gebara
Keyword(s):  
Heat Capacity ◽  
Magnetic Fields ◽  
Curie Temperature ◽  
Specific Heat ◽  
Magnetocaloric Effect ◽  
Intermetallic Compounds ◽  
Indirect Method ◽  
Direct Method ◽  
Capacity Data ◽  
Value Changes

The specific heat and magnetocaloric effect of the LaFe11.2-хMnxCo0.7Si1.1 intermetallic compounds (x = 0.1, 0.2, 0.3) were measured in the temperature range 80–300 K and in magnetic fields up to 8 T. The magnetocaloric effect (MCE) was estimated using two methods: direct method in cyclic magnetic fields, as well as an indirect method from heat capacity data. It was shown that an increase in the concentration of Mn atoms leads to a shift in the Curie temperature of the TC toward lower temperatures, while the FM value changes slightly.

Flow Measurement to a Kaplan Turbine Using a Direct Method and an Indirect One

2016 ◽  
Vol 823 ◽  
pp. 361-366
Author(s):  
Ana Maria Budai ◽  
Adrian Cuzmos ◽  
Cristian Fanica ◽  
Damaschin Pepa ◽  
Cosmin Ursoniu ◽  
...  
Keyword(s):  
Direct Measurement ◽  
Flow Rate ◽  
Flow Measurement ◽  
Indirect Method ◽  
Direct Method ◽  
The Other ◽  
Hydropower Plant ◽  
Kaplan Turbine ◽  
A Direct Method

The paper present two different methods for measuring flow in hydropower, one direct and one indirect method. The study consists in comparing the results obtained by measurements made by both methods in a Romanian hydropower plant. The indirect method used is the Winter-Kennedy method. The other method involves direct measurement of the flow rate of water using a specialized outfit in this.

Isoperimetric Problems in the Calculus of Variations

1952 ◽  
Vol 4 ◽  
pp. 257-280 ◽  
Author(s):  
William Karush
Keyword(s):  
Calculus Of Variations ◽  
Classical Theory ◽  
Indirect Method ◽  
Direct Method ◽  
Isoperimetric Problems ◽  
End Points ◽  
Sufficiency Theorems ◽  
Theory Of Fields ◽  
A Direct Method ◽  
Problem Of Bolza

We are concerned with establishing sufficiency theorems for minima of simple integrals of the parametric type in a class of curves with variable end points and satisfying isoperimetric side conditions. The results which are obtained involve no explicit assumptions of normality. Such results can be derived by transforming our problem to a problem of Bolza and using the latest developments in the theory of that problem. More recently [6] an indirect method of proof has been published. Our object is to present a direct method of proof without transformation of the problem which is based upon a generalization of the classical theory of fields.

scholarly journals Swedish Weight Sounding: A prospective portable soil investigation tools for liquefaction assessment of residential houses in Indonesia

2020 ◽  
Vol 156 ◽  
pp. 02010
Author(s):  
Yusa Muhamad ◽  
Bowman Elisabeth T. ◽  
Nugroho S.A
Keyword(s):  
Indirect Method ◽  
Direct Method ◽  
Low Cost ◽  
Fine Sand ◽  
Good Prospect ◽  
Torque Measurement ◽  
Liquefaction Potential ◽  
Potential Index ◽  
National Disaster ◽  
Liquefaction Assessment

National Disaster Management Agency (BNPB) statistics show that the majority of earthquake affected buildings are residential houses, whereas in practice, soil investigation is rarely conducted for residential houses in Indonesia. This study is preliminary work on the prospective of Swedish Weight Sounding (SWST) for liquefaction assessment for residential houses. Material used is poorly graded sand. The number of half turns from SWST (NSW) per meter for very loose and loose clean fine sand ranges from 4 to 168 (equivalent to SPT 0-30). Liquefaction potential was assessed using an indirect method by converting NSW into equivalent NSPT and direct method. In general, the factor of safety obtained from the direct method is more conservative (thus giving lower liquefaction potential index) than the indirect method. Torque measured for material in this study ranged from 6-54 Nm, equivalent to a specific energy range from 7-70 N/mm2. Liquefaction assessment using SWST data with torque measurement also indicated the soil is liquefiable. SWST also may be able to detect sand ageing. In summary SWS has a good prospect as a highly portable and low cost investigation tool for liquefaction assessment of residential houses in Indonesia.

Simulation study of grass fire using a physics-based model: striving towards numerical rigour and the effect of grass height on the rate of spread

2018 ◽  
Vol 27 (12) ◽  
pp. 800 ◽  
Author(s):  
K. A. M. Moinuddin ◽  
D. Sutherland ◽  
W. Mell
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Heat Release ◽  
Bulk Density ◽  
Simulation Study ◽  
Release Rate ◽  
Rate Of Spread ◽  
Fire Front ◽  
Physics Based Simulation ◽  
Mode A

Grid-independent rate of spread results from a physics-based simulation are presented. Previously, such a numerical benchmark has been elusive owing to computational restrictions. The grid-converged results are used to systematically construct correlations between the rate of spread (RoS) and both wind speed and grass height, separately. The RoS obtained from the physics-based model is found to be linear with wind speed in the parameter range considered. When wind speed is varied, the physics-based model predicts faster RoS than the Mk III and V (McArthur) models (Noble et al. 1980) but slower than the CSIRO model (Cheney et al. 1998). When the grass height is varied keeping the bulk density constant, the fire front changes from a boundary layer flame mode to plume flame mode as the grass height increases. Once the fires are in plume mode, a higher grass height results in a larger heat release rate of the fire but a slower RoS.

The pH of K-deficient muscle

1959 ◽  
Vol 196 (4) ◽  
pp. 811-818 ◽  
Author(s):  
Robert E. Eckel ◽  
Andrew W. Botschner ◽  
Don H. Wood
Keyword(s):  
Indirect Method ◽  
Direct Method ◽  
Dry Weight ◽  
Buffering Capacity ◽  
Muscle Proteins ◽  
Acid Base Balance ◽  
Acid Base ◽  
Weak Bases ◽  
Base Balance ◽  
K Deficiency

The acid-base balance of muscle from control and K-deficient rats was studied. From the measured buffering capacity, 8–11 mEq excess of anions or deficit of cations would be required to acidify 100 gm fat-free dry weight of muscle, 0.5 pH units. No evidence of increased organic acids, increased anionic equivalence of muscle proteins, or of decreased concentrations of weak bases which are potential cations in cell acidosis was found. This evidence, supplemented with data in the literature, fails to account for the cell acidosis reported in the literature. Reliability of the ‘chloride space’ as a measure of the extracellular phase of muscle in K deficiency has been confirmed by showing its agreement with the ‘raffinose space.’ The cell pH has then been calculated from the distribution of CO2 in muscle (indirect method) and from the pH of muscle homogenates (direct method) in control and K-deficient animals. Control and K-deficient muscle pH's are, respectively, 6.89 and 6.83 by the direct method, and 7.11 and 7.05 by the indirect method.

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