9,077 Hits in 1.9 sec

Firebrand generation from burning vegetation

Samuel L. Manzello, Alexander Maranghides, William E. Mell
2007 International journal of wildland fire  
A series of real-scale fire experiments were performed to determine the size and mass distribution of firebrands generated from Douglas-fir (Pseudotsuga menziesii) trees. The experiments were performed in the Large Fire Laboratory at the National Institute of Standards and Technology. The Douglas-fir trees used for the experiments ranged in total height from 2.6 to 5.2 m and the tree moisture content was varied. An array of pans filled with water was used to collect the firebrands that were
more » ... rated from the burning trees. This ensured that firebrands would be quenched as soon as they made contact with the pans. The firebrands were subsequently dried and the sizes were measured using callipers and the dry mass was determined using a precision balance. For all experiments performed, the firebrands were cylindrical in shape. The average firebrand size measured from the 2.6-m Douglas-fir trees was 3 mm in diameter, 40 mm in length. The average firebrand size measured for the 5.2-m Douglas-fir trees was 4 mm in diameter with a length of 53 mm. The mass distribution of firebrands produced from two different tree sizes under similar tree moisture levels was similar. The only noticeable difference occurred in the largest mass class. Firebrands with masses up to 3.5 g to 3.7 g were observed for the larger tree height used (5.2 m). The surface area of the firebrands scaled with firebrand weight. Additional keywords: firebrand collection, size and mass distribution, tree burns.
doi:10.1071/wf06079 fatcat:46exkbvul5empdy73qtp4ay2ii

Firebrand production from burning vegetation

Samuel L. Manzello, Alexander Maranghides, William E. Mell, Thomas G. Cleary, Jiann C. Yang
2006 Forest Ecology and Management  
A series of real scale fire experiments were performed to determine the size and mass distribution of firebrands generated from Douglas-Fir (pseudotsuga menziesii) trees. The results of the real scale fire experiments were used to determine firebrand sizes to perform reduced scale ignition studies of fuel beds in contact with burning firebrands. The firebrand ignition apparatus allowed for the ignition and deposition of both single and multiple firebrands onto the target fuel bed. The moisture
more » ... ontent of the fuel beds used was varied and the fuels considered were pine needle beds, shredded paper beds, and shredded hardwood mulch. Firebrands were constructed by machining wood (Douglass-Fir) into small cylinders of uniform geometry and the size of the cylinders was varied. The firebrand ignition apparatus was installed into the Fire Emulator / Detector Evaluator (FE/DE) to investigate the influence of an air flow on the ignition propensity of fuel beds. Results of this study are presented and compared to relevant studies in the literature.
doi:10.1016/j.foreco.2006.08.160 fatcat:f5dfnyourrdsvjzww5ronoubbq

Radiation and velocity fields induced by localized temperature fluctuations

Howard R. Baum, William E. Mell
2000 Proceedings of the Combustion Institute  
Thus, the radiant heat flux can be written as 1 r q ‫ס‬ ‫מ‬ ٌW (9) j 2 jr j r 4 4 3 W ‫ס‬ (T ( r ) ‫מ‬ T ) E (x) d r (10) o ϱ 2 o Ύ p x r r x ‫ס‬ j|r ‫מ‬ r | (11) o Here, E 2 (x) denotes the exponential  ...  (|y ‫מ‬ y |) E (y ‫ם‬ y ) 2 o 2 o 2 2 ‫ם‬ (y ‫מ‬ y ) ‫מ‬ (23) o ΄ ΅ |y ‫מ‬ y | ( y ‫ם‬ y ) o o Equation 22  ... 
doi:10.1016/s0082-0784(00)80245-3 fatcat:tjptsbylp5fb3ermrvev3xkbgq

Forest Fire Research: The Latest Advances Tools for Understanding and Managing Wildland Fire

Paul-Antoine Santoni, Andrew Sullivan, Dominique Morvan, William E. Mell
2011 Journal of Combustion  
The topics covered by these contributions include a decision support tool to support risk-informed decision-making for individual fires (E.  ... 
doi:10.1155/2011/418756 fatcat:oravb5nkhvdhrjmoxcvbpiraza

A Heat Transfer Model for Firefighters' Protective Clothing, Continued Developments in Protective Clothing Modeling

James R. Lawson, William E. Mell, Kuldeep Prasad
2010 Fire technology  
In the year 2000, a paper entitled "A Heat Transfer Model for Firefighters' Protective Clothing" was published in Volume 36, No.
doi:10.1007/s10694-010-0139-z fatcat:dowtejh56fb7ph6i4iktyohlca

Estimating Fuel Moisture in Grasslands Using UAV-Mounted Infrared and Visible Light Sensors

Nastassia Barber, Ernesto Alvarado, Van R. Kane, William E. Mell, L. Monika Moskal
2021 Sensors  
Predicting wildfire behavior is a complex task that has historically relied on empirical models. Physics-based fire models could improve predictions and have broad applicability, but these models require more detailed inputs, including spatially explicit estimates of fuel characteristics. One of the most critical of these characteristics is fuel moisture. Obtaining moisture measurements with traditional destructive sampling techniques can be prohibitively time-consuming and extremely limited in
more » ... spatial resolution. This study seeks to assess how effectively moisture in grasses can be estimated using reflectance in six wavelengths in the visible and infrared ranges. One hundred twenty 1 m-square field samples were collected in a western Washington grassland as well as overhead imagery in six wavelengths for the same area. Predictive models of vegetation moisture using existing vegetation indices and components from principal component analysis of the wavelengths were generated and compared. The best model, a linear model based on principal components and biomass, showed modest predictive power (r² = 0.45). This model performed better for the plots with both dominant grass species pooled than it did for each species individually. The presence of this correlation, especially given the limited moisture range of this study, suggests that further research using samples across the entire fire season could potentially produce effective models for estimating moisture in this type of ecosystem using unmanned aerial vehicles, even when more than one major species of grass is present. This approach would be a fast and flexible approach compared to traditional moisture measurements.
doi:10.3390/s21196350 pmid:34640670 fatcat:yoq3q2a7mvb5vhptl7z6fntnjq

Linking 3D spatial models of fuels and fire: Effects of spatial heterogeneity on fire behavior

Russell A. Parsons, William E. Mell, Peter McCauley
2011 Ecological Modelling  
Acknowledgements We wish to acknowledge E. Reinhardt and R. Keane for use of data from their crown fuels field study.  ...  Mechanistic physics-based fire behavior models have been recently developed which can address fuel heterogeneity (Mell et al., 1996 (Mell et al., , 2007 (Mell et al., , 2009 Linn, 1997; Morvan and Dupuy  ...  However, evidence suggests that fire behavior is sensitive to fine scale spatial variability, including size, shape and orientation of particles, and distance between them (Fons, 1946; Vogel and Williams  ... 
doi:10.1016/j.ecolmodel.2010.10.023 fatcat:rtvlxlq2yresddaevre3zkkfzu

The wildland–urban interface fire problem – current approaches and research needs

William E. Mell, Samuel L. Manzello, Alexander Maranghides, David Butry, Ronald G. Rehm
2010 International journal of wildland fire  
Blanchi and Leonard 2005; Maranghides and Mell 2009 ).  ...  Cohen 1995; Blanchi and Leonard 2005; Maranghides and Mell 2009 ).  ... 
doi:10.1071/wf07131 fatcat:ik25wsk32jbgzlk5pwuj4b2cve

On the development and characterization of a firebrand generator

Samuel L. Manzello, John R. Shields, Thomas G. Cleary, Alexander Maranghides, William E. Mell, Jiann C. Yang, Yoshihiko Hayashi, Daisaku Nii, Tsuyoshi Kurita
2008 Fire safety journal  
A unique experimental apparatus has been constructed in order to generate a controlled and repeatable size and mass distribution of glowing firebrands. The present study reports on a series of experiments conducted in order to characterize the performance of this firebrand generator. Firebrand generator characterization experiments were performed at the Fire Research Wind Tunnel Facility (FRWTF) at the Building Research Institute (BRI) in Tsukuba, Japan. The firebrand generator was fed with
more » ... e different initial firebrand geometries; two different sized cylinders and one size of disks. Cylinders were used to simulate firebrand fluxes from vegetation, such as trees, while disks were used to simulate a firebrand flux from burning structures. Samples of these geometries were constructed from wood dowels, fed into the firebrand generator, ignited, and the glowing firebrands generated were collected using an array of water filled pans. The pans were filled with water in order to quench combustion. The collected firebrands were subsequently dried and the size and mass distribution was measured. These experiments were performed over a range of wind tunnel speeds, with no wind speed present to 9 m/s, to determine the lofting distance of the firebrands generated. Finally, the size and mass distribution produced from the firebrand generator are compared to those produced from burning trees. Results of the study are presented and discussed. ACCEPTED FOR PUBLICATION: FIRE SAFETY JOURNAL 1 Corresponding author:, +1-301-975-6891 (office), +1-301-975-4052 (fax)
doi:10.1016/j.firesaf.2007.10.001 fatcat:5iayqk3yzbcqjfpcnqyemtdtxe

A comparison of level set and marker methods for the simulation of wildland fire front propagation

Anthony S. Bova, William E. Mell, Chad M. Hoffman
2016 International journal of wildland fire  
E " # 1 B ðf S;x ; f S;y Þ where f s has been substituted for f w in the point function Eqn A1, which was then solved for U.  ...  A grassland fuel model was created with attributes similar to those of Eriachne burkittii (kerosene grass), as described in Mell et al. (2007) .  ...  At time t n , gradients of f LS at the grid locations (i, j) are computed as central differences (here and below we omit the subscript 'LS' to simplify the notation): where df/dx E @f/@x and df/dy E @f  ... 
doi:10.1071/wf13178 fatcat:f353a2wt2fgsxlw6gdfljp7i5e

Orthorectification of Helicopter-Borne High Resolution Experimental Burn Observation from Infra Red Handheld Imagers

Ronan Paugam, Martin J. Wooster, William E. Mell, Mélanie C. Rochoux, Jean-Baptiste Filippi, Gernot Rücker, Olaf Frauenberger, Eckehard Lorenz, Wilfrid Schroeder, Bruce Main, Navashni Govender
2021 Remote Sensing  
To pursue the development and validation of coupled fire-atmosphere models, the wildland fire modeling community needs validation data sets with scenarios where fire-induced winds influence fire front behavior, and with high temporal and spatial resolution. Helicopter-borne infrared thermal cameras have the potential to monitor landscape-scale wildland fires at a high resolution during experimental burns. To extract valuable information from those observations, three-step image processing is
more » ... uired: (a) Orthorectification to warp raw images on a fixed coordinate system grid, (b) segmentation to delineate the fire front location out of the orthorectified images, and (c) computation of fire behavior metrics such as the rate of spread from the time-evolving fire front location. This work is dedicated to the first orthorectification step, and presents a series of algorithms that are designed to process handheld helicopter-borne thermal images collected during savannah experimental burns. The novelty in the approach lies on its recursive design, which does not require the presence of fixed ground control points, hence relaxing the constraint on field of view coverage and helping the acquisition of high-frequency observations. For four burns ranging from four to eight hectares, long-wave and mid infra red images were collected at 1 and 3 Hz, respectively, and orthorectified at a high spatial resolution (<1 m) with an absolute accuracy estimated to be lower than 4 m. Subsequent computation of fire radiative power is discussed with comparison to concurrent space-borne measurements.
doi:10.3390/rs13234913 fatcat:zvefyewm5jgi3f75d7mptqn6ti

Clitoral therapy device for treatment of sexual dysfunction in irradiated cervical cancer patients

MaryAnn Schroder, Loren K. Mell, Jean A. Hurteau, Yvonne C. Collins, Jacob Rotmensch, Steven E. Waggoner, S. Diane Yamada, William Small, Arno J. Mundt
2005 International Journal of Radiation Oncology, Biology, Physics  
Purpose: The purpose of this pilot study was to evaluate the efficacy of the clitoral therapy device (Eros Therapy) in alleviating sexual dysfunction in irradiated cervical cancer patients. Methods and Materials: Eligible patients had a history of cervical cancer treated with radiotherapy and self-reported sexual dysfunction of sexual arousal and/or orgasmic disorders. Patients used the noninvasive, nonpharmacologic clitoral therapy device using a hand-held, battery-powered vacuum to cause
more » ... ral engorgement four times weekly for 3 months during foreplay and self-stimulation. Study instruments included the Female Sexual Function Index, Derogatis Interview for Sexual Functioning, and Dyadic Adjustment Scale. The outcome evaluation was performed at 3 months. Results: Between 2001 and 2002, 15 women were enrolled and 13 completed the study. The median patient age and radiotherapy-enrollment interval was 43.5 years and 2 years, respectively. At baseline, all patients reported symptoms of sexual arousal and/or orgasmic disorders, and some also had sexual desire and pain disorders. At 3 months, statistically significant improvements were seen in all domains tested, including sexual desire, arousal, lubrication, orgasm, sexual satisfaction, and reduced pain. The median Female Sexual Function Index total score increased from 17 to 29.4 (maximal score, 36; p <0.001). The median Derogatis Interview for Sexual Functioning total raw score increased from 46 to 95 (maximal score, 118; p <0.001). At baseline, the Derogatis Interview for Sexual Functioning total T-score corresponded to the bottom 10th percentile of normal sexual functioning. At 3 months, the total T-score placed the patients at the normalcy cutoff. Gynecologic examinations revealed improved mucosal color and moisture and vaginal elasticity and decreased bleeding and ulceration. Conclusion: Our results from this pilot study suggest that the clitoral therapy device may alleviate sexual dysfunction in irradiated cervical cancer patients. A randomized, controlled trial is warranted to assess the full benefits of this approach.
doi:10.1016/j.ijrobp.2004.07.728 pmid:15752887 fatcat:vi26b6bqbvgrpdy4nepmxik6mi

Origin of pingo-like features on the Beaufort Sea shelf and their possible relationship to decomposing methane gas hydrates

Charles K. Paull, William Ussler, Scott R. Dallimore, Steve M. Blasco, Thomas D. Lorenson, Humfrey Melling, Barbara E. Medioli, F. Mark Nixon, Fiona A. McLaughlin
2007 Geophysical Research Letters  
doi:10.1029/2006gl027977 fatcat:lqrkeg7fprfyfposbvomrytxoa

FXR inhibition reduces ACE2 expression, SARS-CoV-2 infection and may improve COVID-19 outcome [article]

Teresa Brevini, Mailis Maes, Gwilym J Webb, William T H Gelson, Sally Forrest, Petra Mlcochova, Scott Dillon, Sagar Varankar, Mahnaz Darvish-Damavandi, Victoria L Mulcahy, Rhoda E Kuc, Thomas L Williams (+29 others)
2021 bioRxiv   pre-print
(c-e) ACE2 enzymatic activity (c), 4 QPCR (d) and immunofluorescence (e) demonstrating that UDCA treatment reduces ACE2 5 levels in ESNP.  ...  (e) Schematic 4 illustrating the experimental design corresponding to (f).  ... 
doi:10.1101/2021.06.06.446781 fatcat:t2d2elfp7bfnng5meg6prvqnci

Freshwater and its role in the Arctic Marine System: Sources, disposition, storage, export, and physical and biogeochemical consequences in the Arctic and global oceans

E. C. Carmack, M. Yamamoto-Kawai, T. W. N. Haine, S. Bacon, B. A. Bluhm, C. Lique, H. Melling, I. V. Polyakov, F. Straneo, M.-L. Timmermans, W. J. Williams
2016 Journal of Geophysical Research - Biogeosciences  
Williams, The contiguous panarctic Riverine Coastal Domain: A unifying concept, 2015, copyright 2015, with permission from Elsevier. L. E.  ...  Reprinted from Progress in Oceanography, Carmack, E. C., P. Winsor, and W.  ... 
doi:10.1002/2015jg003140 fatcat:jqjfzs3igfgrxfpkupfseuje2a
« Previous Showing results 1 — 15 out of 9,077 results