Comparison of burning characteristics of live and dead chaparral fuels

Treesearch

L. Sun; X. Zhou; S. Mahalingam; D.R. Weise

2006-01-01

Wildfire spread in living vegetation, such as chaparral in southern California, often causes significant damage to infrastructure and ecosystems. The effects of physical characteristics of fuels and fuel beds on live fuel burning and whether live fuels differ fundamentally from dead woody fuels in their burning characteristics are not well understood. Toward this end,...

Prescribed burning in ponderosa pine: fuel reductions and redistributing fuels near boles to prevent injury

USDA-ARS?s Scientific Manuscript database

Prescribed burning can be an effective tool for thinning forests and reducing fuels to lessen wildfire risks. However, prescribed burning sometimes fails to substantially reduce fuels and sometimes damages/kills valuable, large trees. This study compared fuel reductions between fall and spring pre...

Experimental Investigations Of The Influence Of Pressure On Critical Extinction Conditions Of Laminar Nonpremixed Flames Burning Condensed Hydrocarbon Fuels, Jet Fuels, And Surrogates

DTIC Science & Technology

2014-10-25

cycloalkanes, aromatics, and alkenes [3,23–26]. On average, the composition by volume is approximately 60% alkanes, 20% cycloalkanes, 18% aromatics, and 2... alkenes [26]. Efforts to develop chemical-kinetic models that accurately describe the combustion of these practical fuels are critical to the development... method also allows for measurements of fuel mass burning rates by recording the required fuel feed rate to maintain the fuel cup level under steady

Local Burn-Up Effects in the NBSR Fuel Element

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown N. R.; Hanson A.; Diamond, D.

2013-01-31

This study addresses the over-prediction of local power when the burn-up distribution in each half-element of the NBSR is assumed to be uniform. A single-element model was utilized to quantify the impact of axial and plate-wise burn-up on the power distribution within the NBSR fuel elements for both high-enriched uranium (HEU) and low-enriched uranium (LEU) fuel. To validate this approach, key parameters in the single-element model were compared to parameters from an equilibrium core model, including neutron energy spectrum, power distribution, and integral U-235 vector. The power distribution changes significantly when incorporating local burn-up effects and has lower power peakingmore » relative to the uniform burn-up case. In the uniform burn-up case, the axial relative power peaking is over-predicted by as much as 59% in the HEU single-element and 46% in the LEU single-element with uniform burn-up. In the uniform burn-up case, the plate-wise power peaking is over-predicted by as much as 23% in the HEU single-element and 18% in the LEU single-element. The degree of over-prediction increases as a function of burn-up cycle, with the greatest over-prediction at the end of Cycle 8. The thermal flux peak is always in the mid-plane gap; this causes the local cumulative burn-up near the mid-plane gap to be significantly higher than the fuel element average. Uniform burn-up distribution throughout a half-element also causes a bias in fuel element reactivity worth, due primarily to the neutronic importance of the fissile inventory in the mid-plane gap region.« less

Burning Fuel Droplet

NASA Technical Reports Server (NTRS)

2003-01-01

Fuel ignites and burns in the Droplet Combustion Experiment (DCE) on STS-94 on July 4 1997, MET:2/05:40 (approximate). The DCE was designed to investigate the fundamental combustion aspects of single, isolated droplets under different pressures and ambient oxygen concentrations for a range of droplet sizes varying between 2 and 5 mm. DCE used various fuels -- in drops ranging from 1 mm (0.04 inches) to 5 mm (0.2 inches) -- and mixtures of oxidizers and inert gases to learn more about the physics of combustion in the simplest burning configuration, a sphere. The experiment elapsed time is shown at the bottom of the composite image. The DCE principal investigator was Forman Williams, University of California, San Diego. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1R mission (STS-94, July 1-17 1997). Advanced combustion experiments will be a part of investigations plarned for the International Space Station. (121KB JPEG, 654 x 977 pixels; downlinked video, higher quality not available) The MPG from which this composite was made is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300169.html.

Comprehensive laboratory measurements of biomass-burning emissions: 1. Emissions from Indonesian, African, and other fuels

NASA Astrophysics Data System (ADS)

Christian, T. J.; Kleiss, B.; Yokelson, R. J.; Holzinger, R.; Crutzen, P. J.; Hao, W. M.; Saharjo, B. H.; Ward, D. E.

2003-12-01

Trace gas and particle emissions were measured from 47 laboratory fires burning 16 regionally to globally significant fuel types. Instrumentation included the following: open-path Fourier transform infrared spectroscopy; proton transfer reaction mass spectrometry; filter sampling with subsequent analysis of particles with diameter <2.5 μm for organic and elemental carbon and other elements; and canister sampling with subsequent analysis by gas chromatography (GC)/flame ionization detector, GC/electron capture detector, and GC/mass spectrometry. The emissions of 26 compounds are reported by fuel type. The results include the first detailed measurements of the emissions from Indonesian fuels. Carbon dioxide, CO, CH4, NH3, HCN, methanol, and acetic acid were the seven most abundant emissions (in order) from burning Indonesian peat. Acetol (hydroxyacetone) was a major, previously unobserved emission from burning rice straw (21-34 g/kg). The emission factors for our simulated African fires are consistent with field data for African fires for compounds measured in both the laboratory and the field. However, the higher concentrations and more extensive instrumentation in this work allowed quantification of at least 10 species not previously quantified for African field fires (in order of abundance): acetaldehyde, phenol, acetol, glycolaldehyde, methylvinylether, furan, acetone, acetonitrile, propenenitrile, and propanenitrile. Most of these new compounds are oxygenated organic compounds, which further reinforces the importance of these reactive compounds as initial emissions from global biomass burning. A few high-combustion-efficiency fires emitted very high levels of elemental (black) carbon, suggesting that biomass burning may produce more elemental carbon than previously estimated.

The investigation of critical burning of fuel droplets

NASA Technical Reports Server (NTRS)

Allison, C. B.; Canada, G. S.; Faeth, G. M.

1973-01-01

The combustion and evaporation of liquid fuels at high pressures were investigated. Particular emphasis was placed on conditions where the liquid surface approaches the thermodynamic critical point during combustion. The influence of transient effects on a burning liquid fuel was also investigated through both analysis and measurements of the response of liquid monopropellant combustion to imposed pressure oscillations. Work was divided into four phases (1) Droplet combustion at high pressures, which consider both measurement and analysis of the porous sphere burning rate of liquids in a natural convection environment at elevated pressure. (2) High pressure droplet burning in combustion gases, which involved steady burning and evaporation of liquids from porous spheres in a high pressure environment that simulates actual combustion chamber conditions. (3) Liquid strand combustion, which considered the burning rate, the state of the liquid surface and the liquid phase temperature distribution of a burning liquid monopropellant column over a range of pressures. (4) Oscillatory combustion, which was a theoretical and experimental investigation of the response of a burning liquid monopropellant to pressure oscillations.

Prescribed burning in ponderosa pine: fuel reductions and redistributing fuels near boles to prevent injury

Treesearch

Robert A. Progar; Kathryn H. Hrinkevich; Edward S. Clark; Matthew J. Rinella

2017-01-01

Fire suppression and other factors have resulted in high wildfire risk in the western US, and prescribed burning can be an effective tool for thinning forests and reducing fuels to lessen wildfire risks. However, prescribed burning sometimes fails to substantially reduce fuels and sometimes damages and kills valuable, large trees. This study compared fuel reductions...

Fire hazard after prescribed burning in a gorse shrubland: implications for fuel management.

PubMed

Marino, Eva; Guijarro, Mercedes; Hernando, Carmen; Madrigal, Javier; Díez, Carmen

2011-03-01

Prescribed burning is commonly used to prevent accumulation of biomass in fire-prone shrubland in NW Spain. However, there is a lack of knowledge about the efficacy of the technique in reducing fire hazard in these ecosystems. Fire hazard in burned shrubland areas will depend on the initial capacity of woody vegetation to recover and on the fine ground fuels existing after fire. To explore the effect that time since burning has on fire hazard, experimental tests were performed with two fuel complexes (fine ground fuels and regenerated shrubs) resulting from previous prescribed burnings conducted in a gorse shrubland (Ulex europaeus L.) one, three and five years earlier. A point-ignition source was used in burning experiments to assess ignition and initial propagation success separately for each fuel complex. The effect of wind speed was also studied for shrub fuels, and several flammability parameters were measured. Results showed that both ignition and initial propagation success of fine ground fuels mainly depended on fuel depth and were independent of time since burning, although flammability parameters indicated higher fire hazard three years after burning. In contrast, time since burning increased ignition and initial propagation success of regenerated shrub fuels, as well as the flammability parameters assessed, but wind speed had no significant effect. The combination of results of fire hazard for fine ground fuels and regenerated shrubs according to the variation in relative coverage of each fuel type after prescribed burning enabled an assessment of integrated fire hazard in treated areas. The present results suggest that prescribed burning is a very effective technique to reduce fire hazard in the study area, but that fire hazard will be significantly increased by the third year after burning. These results are valuable for fire prevention and fuel management planning in gorse shrubland areas. Copyright © 2010 Elsevier Ltd. All rights reserved.

Molecular characterization of urban organic aerosol in tropical India: contributions of biomass/biofuel burning, plastic burning, and fossil fuel combustion

NASA Astrophysics Data System (ADS)

Fu, P. Q.; Kawamura, K.; Pavuluri, C. M.; Swaminathan, T.

2009-10-01

Organic molecular composition of PM10 samples, collected at Chennai in tropical India, was studied using capillary gas chromatography/mass spectrometry. Twelve organic compound classes were detected in the aerosols, including aliphatic lipids, sugar compounds, lignin products, terpenoid biomarkers, sterols, aromatic acids, phthalates, hopanes, and polycyclic aromatic hydrocarbons (PAHs). At daytime, phthalates was found to be the most abundant compound class; while at nighttime, fatty acids was the dominant one. Concentrations of total quantified organics were higher in summer (611-3268 ng m-3, average 1586 ng m-3) than in winter (362-2381 ng m-3, 1136 ng m-3), accounting for 11.5±1.93% and 9.35±1.77% of organic carbon mass in summer and winter, respectively. Di-(2-ethylhexyl) phthalate, C16 fatty acid, and levoglucosan were identified as the most abundant single compounds. The nighttime maxima of most organics in the aerosols indicate a land/sea breeze effect in tropical India, although some other factors such as local emissions and long-range transport may also influence the composition of organic aerosols. The abundances of anhydrosugars (e.g., levoglucosan), lignin and resin products, hopanes and PAHs in the Chennai aerosols suggest that biomass burning and fossil fuel combustion are significant sources of organic aerosols in tropical India. Interestingly, terephthalic acid was maximized at nighttime, which is different from those of phthalic and isophthalic acids. A positive correlation was found between the concentration of 1,3,5-triphenylbenzene (a tracer for plastic burning) and terephthalic acid, suggesting that field burning of municipal solid wastes including plastics is a significant source of terephthalic acid. This study demonstrates that, in addition to biomass burning and fossil fuel combustion, the open-burning of plastics also contributes to the organic aerosols in South Asia.

Fine scale vegetation classification and fuel load mapping for prescribed burning

Treesearch

Andrew D. Bailey; Robert Mickler

2007-01-01

Fire managers in the Coastal Plain of the Southeastern United States use prescribed burning as a tool to reduce fuel loads in a variety of vegetation types, many of which have elevated fuel loads due to a history of fire suppression. While standardized fuel models are useful in prescribed burn planning, those models do not quantify site-specific fuel loads that reflect...

Particle agglomeration and fuel decomposition in burning slurry droplets

NASA Astrophysics Data System (ADS)

Choudhury, P. Roy; Gerstein, Melvin

In a burning slurry droplet the particles tend to agglomerate and produce large clusters which are difficult to burn. As a consequence, the combustion efficiency is drastically reduced. For such a droplet the nonlinear D2- t behavior associated with the formation of hard to burn agglomerates can be explained if the fuel decomposes on the surface of the particles. This paper deals with analysis and experiments with JP-10 and Diesel #2 slurries prepared with inert SiC and Al 2O 3 particles. It provides direct evidence of decomposed fuel residue on the surface of the particles heated by flame radiation. These decomposed fuel residues act as bonding agents and appear to be responsible for the observed agglomeration of particles in a slurry. Chemical analysis, scanning electron microscope photographs and finally micro-analysis by electron scattering clearly show the presence of decomposed fuel residue on the surface of the particles. Diesel #2 is decomposed relatively easily and therefore leaves a thicker deposit on SiC and forms larger agglomerates than the more stable JP-10. A surface reaction model with particles heated by flame radiation is able to describe the observed trend of the diameter history of the slurry fuel. Additional experiments with particles of lower emissivity (Al 2O 3) and radiation absorbing dye validate the theoretical model of the role of flame radiation in fuel decomposition and the formation of agglomerates in burning slurry droplets.

Chemical composition of air masses transported from Asia to the U.S. West Coast during ITCT 2K2: Fossil fuel combustion versus biomass-burning signatures

NASA Astrophysics Data System (ADS)

de Gouw, J. A.; Cooper, O. R.; Warneke, C.; Hudson, P. K.; Fehsenfeld, F. C.; Holloway, J. S.; Hübler, G.; Nicks, D. K., Jr.; Nowak, J. B.; Parrish, D. D.; Ryerson, T. B.; Atlas, E. L.; Donnelly, S. G.; Schauffler, S. M.; Stroud, V.; Johnson, K.; Carmichael, G. R.; Streets, D. G.

2004-12-01

As part of the Intercontinental Transport and Chemical Transformation experiment in 2002 (ITCT 2K2), a National Oceanic and Atmospheric Administration (NOAA) WP-3D research aircraft was used to study the long-range transport of Asian air masses toward the west coast of North America. During research flights on 5 and 17 May, strong enhancements of carbon monoxide (CO) and other species were observed in air masses that had been transported from Asia. The hydrocarbon composition of the air masses indicated that the highest CO levels were related to fossil fuel use. During the flights on 5 and 17 May and other days, the levels of several biomass-burning indicators increased with altitude. This was true for acetonitrile (CH3CN), methyl chloride (CH3Cl), the ratio of acetylene (C2H2) to propane (C3H8), and, on May 5, the percentage of particles measured by the particle analysis by laser mass spectrometry (PALMS) instrument that were attributed to biomass burning based on their carbon and potassium content. An ensemble of back-trajectories, calculated from the U.S. west coast over a range of latitudes and altitudes for the entire ITCT 2K2 period, showed that air masses from Southeast Asia and China were generally observed at higher altitudes than air from Japan and Korea. Emission inventories estimate the contribution of biomass burning to the total emissions to be low for Japan and Korea, higher for China, and the highest for Southeast Asia. Combined with the origin of the air masses versus altitude, this qualitatively explains the increase with altitude, averaged over the whole ITCT 2K2 period, of the different biomass-burning indicators.

An experimental prescribed burn to reduce fuel hazard in chaparral

Treesearch

Lisle R. Green

1970-01-01

The feasibility of reducing fuel hazard in chaparral during safe weather conditions was studied in an experimental prescribed burn in southern California. Burning was done under fuel and weather conditions when untreated brush would not bum readily. Preparatory treatment included smashing of brush on strips with a bulldozer, and reduction of moisture content of leaves...

Ambient measurements and source apportionment of fossil fuel and biomass burning black carbon in Ontario

NASA Astrophysics Data System (ADS)

Healy, R. M.; Sofowote, U.; Su, Y.; Debosz, J.; Noble, M.; Jeong, C.-H.; Wang, J. M.; Hilker, N.; Evans, G. J.; Doerksen, G.; Jones, K.; Munoz, A.

2017-07-01

Black carbon (BC) is of significant interest from a human exposure perspective but also due to its impacts as a short-lived climate pollutant. In this study, sources of BC influencing air quality in Ontario, Canada were investigated using nine concurrent Aethalometer datasets collected between June 2015 and May 2016. The sampling sites represent a mix of background and near-road locations. An optical model was used to estimate the relative contributions of fossil fuel combustion and biomass burning to ambient concentrations of BC at every site. The highest annual mean BC concentration was observed at a Toronto highway site, where vehicular traffic was found to be the dominant source. Fossil fuel combustion was the dominant contributor to ambient BC at all sites in every season, while the highest seasonal biomass burning mass contribution (35%) was observed in the winter at a background site with minimal traffic contributions. The mass absorption cross-section of BC was also investigated at two sites, where concurrent thermal/optical elemental carbon data were available, and was found to be similar at both locations. These results are expected to be useful for comparing the optical properties of BC at other near-road environments globally. A strong seasonal dependence was observed for fossil fuel BC at every Ontario site, with mean summer mass concentrations higher than their respective mean winter mass concentrations by up to a factor of two. An increased influence from transboundary fossil fuel BC emissions originating in Michigan, Ohio, Pennsylvania and New York was identified for the summer months. The findings reported here indicate that BC should not be considered as an exclusively local pollutant in future air quality policy decisions. The highest seasonal difference was observed at the highway site, however, suggesting that changes in fuel composition may also play an important role in the seasonality of BC mass concentrations in the near-road environment

Laboratory Studies of Water Uptake by Biomass Burning Smoke: Role of Fuel Inorganic Content, Combustion Phase and Aging

NASA Astrophysics Data System (ADS)

Dubey, M. K.; Bixler, S. L.; Romonosky, D.; Lam, J.; Carrico, C.; Aiken, A. C.

2017-12-01

Biomass burning aerosol emissions have substantially increased with observed warming and drying in the southwestern US. While wildfires are projected to intensify missing knowledge on the aerosols hampers assessments. Observations demonstrate that enhanced light absorption by coated black carbon and brown carbon can offset the cooling effects of organic aerosols in wildfires. However, if mixing processes that enhance this absorption reduce the aerosol lifetime it would lower their atmospheric burden. In order to elucidate mechanisms regulating this tradeoff we performed laboratory studies of smoke from biomass burning. We focus on aerosol optical properties and their hygroscopic response. Fresh emissions from burning 30 fuels under flaming and smoldering conditions were investigated. We measured aerosol absorption, scattering and extinction at multiple wavelengths, water uptake at 85% relative humidity (fRH85%) with a humidity controlled dual nephelometer, and black carbon mass with a SP2. Trace gases and the ionic content of the fuel and smoke were also measured We find that whereas the optical properties of smoke were strongly dictated by the flaming versus smoldering nature of the burn, the observed hygroscopicity was intimately linked to the chemical composition of the fuel. The mean hygroscopicity ranged from nearly hydrophobic (fRH85% = 1) to very hydrophilic (fRH85% = 2.1) values typical of pure deliquescent salts. The k values varied from 0.004 to 0.18 and correlated well with inorganic content. Inorganic fuel content was the key driver of hygroscopicity with combustion phase playing a secondary but important role ( 20%). Flaming combustion promoted hygroscopicity by generating refractory black carbon and ions. Smoldering combustion suppressed hygroscopicity by producing hydrogenated organic species. Wildfire smoke was hydrophobic since the evergreen species with low inorganic content dominated in these fires. We also quantify the mass absorption cross

Studying the effects of fuel treatment based on burn probability on a boreal forest landscape.

PubMed

Liu, Zhihua; Yang, Jian; He, Hong S

2013-01-30

Fuel treatment is assumed to be a primary tactic to mitigate intense and damaging wildfires. However, how to place treatment units across a landscape and assess its effectiveness is difficult for landscape-scale fuel management planning. In this study, we used a spatially explicit simulation model (LANDIS) to conduct wildfire risk assessments and optimize the placement of fuel treatments at the landscape scale. We first calculated a baseline burn probability map from empirical data (fuel, topography, weather, and fire ignition and size data) to assess fire risk. We then prioritized landscape-scale fuel treatment based on maps of burn probability and fuel loads (calculated from the interactions among tree composition, stand age, and disturbance history), and compared their effects on reducing fire risk. The burn probability map described the likelihood of burning on a given location; the fuel load map described the probability that a high fuel load will accumulate on a given location. Fuel treatment based on the burn probability map specified that stands with high burn probability be treated first, while fuel treatment based on the fuel load map specified that stands with high fuel loads be treated first. Our results indicated that fuel treatment based on burn probability greatly reduced the burned area and number of fires of different intensities. Fuel treatment based on burn probability also produced more dispersed and smaller high-risk fire patches and therefore can improve efficiency of subsequent fire suppression. The strength of our approach is that more model components (e.g., succession, fuel, and harvest) can be linked into LANDIS to map the spatially explicit wildfire risk and its dynamics to fuel management, vegetation dynamics, and harvesting. Copyright © 2012 Elsevier Ltd. All rights reserved.

Charring temperatures are driven by the fuel types burned in a peatland wildfire

PubMed Central

Hudspith, Victoria A.; Belcher, Claire M.; Yearsley, Jonathan M.

2014-01-01

Peatlands represent a globally important carbon store; however, the human exploitation of this ecosystem is increasing both the frequency and severity of fires on drained peatlands. Yet, the interactions between the hydrological conditions (ecotopes), the fuel types being burned, the burn severity, and the charring temperatures (pyrolysis intensity) remain poorly understood. Here we present a post-burn assessment of a fire on a lowland raised bog in Co. Offaly, Ireland (All Saints Bog). Three burn severities were identified in the field (light, moderate, and deeply burned), and surface charcoals were taken from 17 sites across all burn severities. Charcoals were classified into two fuel type categories (either ground or aboveground fuel) and the reflectance of each charcoal particle was measured under oil using reflectance microscopy. Charcoal reflectance shows a positive relationship with charring temperature and as such can be used as a temperature proxy to reconstruct minimum charring temperatures after a fire event. Resulting median reflectance values for ground fuels are 1.09 ± 0.32%Romedian, corresponding to estimated minimum charring temperatures of 447°C ± 49°C. In contrast, the median charring temperatures of aboveground fuels were found to be considerably higher, 646°C ± 73°C (3.58 ± 0.77%Romedian). A mixed-effects modeling approach was used to demonstrate that the interaction effects of burn severity, as well as ecotope classes, on the charcoal reflectance is small compared to the main effect of fuel type. Our findings reveal that the different fuel types on raised bogs are capable of charring at different temperatures within the same fire, and that the pyrolysis intensity of the fire on All Saints Bog was primarily driven by the fuel types burning, with only a weak association to the burn severity or ecotope classes. PMID:25566288

Technologies and Concepts for Reducing the Fuel Burn of Subsonic Transport Aircraft

NASA Technical Reports Server (NTRS)

Nickol, Craig L.

2012-01-01

There are many technologies under development that have the potential to enable large fuel burn reductions in the 2025 timeframe for subsonic transport aircraft relative to the current fleet. This paper identifies a potential technology suite and analyzes the fuel burn reduction potential of these technologies when integrated into advanced subsonic transport concepts. Advanced tube-and-wing concepts are developed in the single aisle and large twin aisle class, and a hybrid-wing-body concept is developed for the large twin aisle class. The resulting fuel burn reductions for the advanced tube-and-wing concepts range from a 42% reduction relative to the 777-200 to a 44% reduction relative to the 737-800. In addition, the hybrid-wingbody design resulted in a 47% fuel burn reduction relative to the 777-200. Of course, to achieve these fuel burn reduction levels, a significant amount of technology and concept maturation is required between now and 2025. A methodology for capturing and tracking concept maturity is also developed and presented in this paper.

Mercury emissions from biomass burning in China.

PubMed

Huang, Xin; Li, Mengmeng; Friedli, Hans R; Song, Yu; Chang, Di; Zhu, Lei

2011-11-01

Biomass burning covers open fires (forest and grassland fires, crop residue burning in fields, etc.) and biofuel combustion (crop residues and wood, etc., used as fuel). As a large agricultural country, China may produce large quantities of mercury emissions from biomass burning. A new mercury emission inventory in China is needed because previous studies reflected outdated biomass burning with coarse resolution. Moreover, these studies often adopted the emission factors (mass of emitted species per mass of biomass burned) measured in North America. In this study, the mercury emissions from biomass burning in China (excluding small islands in the South China Sea) were estimated, using recently measured mercury concentrations in various biomes in China as emission factors. Emissions from crop residues and fuelwood were estimated based on annual reports distributed by provincial government. Emissions from forest and grassland fires were calculated by combining moderate resolution imaging spectroradiometer (MODIS) burned area product with combustion efficiency (ratio of fuel consumption to total available fuels) considering fuel moisture. The average annual emission from biomass burning was 27 (range from 15.1 to 39.9) Mg/year. This inventory has high spatial resolution (1 km) and covers a long period (2000-2007), making it useful for air quality modeling.

Global combustion: the connection between fossil fuel and biomass burning emissions (1997-2010).

PubMed

Balch, Jennifer K; Nagy, R Chelsea; Archibald, Sally; Bowman, David M J S; Moritz, Max A; Roos, Christopher I; Scott, Andrew C; Williamson, Grant J

2016-06-05

Humans use combustion for heating and cooking, managing lands, and, more recently, for fuelling the industrial economy. As a shift to fossil-fuel-based energy occurs, we expect that anthropogenic biomass burning in open landscapes will decline as it becomes less fundamental to energy acquisition and livelihoods. Using global data on both fossil fuel and biomass burning emissions, we tested this relationship over a 14 year period (1997-2010). The global average annual carbon emissions from biomass burning during this time were 2.2 Pg C per year (±0.3 s.d.), approximately one-third of fossil fuel emissions over the same period (7.3 Pg C, ±0.8 s.d.). There was a significant inverse relationship between average annual fossil fuel and biomass burning emissions. Fossil fuel emissions explained 8% of the variation in biomass burning emissions at a global scale, but this varied substantially by land cover. For example, fossil fuel burning explained 31% of the variation in biomass burning in woody savannas, but was a non-significant predictor for evergreen needleleaf forests. In the land covers most dominated by human use, croplands and urban areas, fossil fuel emissions were more than 30- and 500-fold greater than biomass burning emissions. This relationship suggests that combustion practices may be shifting from open landscape burning to contained combustion for industrial purposes, and highlights the need to take into account how humans appropriate combustion in global modelling of contemporary fire. Industrialized combustion is not only an important driver of atmospheric change, but also an important driver of landscape change through companion declines in human-started fires.This article is part of the themed issue 'The interaction of fire and mankind'. © 2016 The Author(s).

Biomass burning fuel consumption dynamics in the tropics and subtropics assessed from satellite

NASA Astrophysics Data System (ADS)

Andela, Niels; van der Werf, Guido R.; Kaiser, Johannes W.; van Leeuwen, Thijs T.; Wooster, Martin J.; Lehmann, Caroline E. R.

2016-06-01

Landscape fires occur on a large scale in (sub)tropical savannas and grasslands, affecting ecosystem dynamics, regional air quality and concentrations of atmospheric trace gasses. Fuel consumption per unit of area burned is an important but poorly constrained parameter in fire emission modelling. We combined satellite-derived burned area with fire radiative power (FRP) data to derive fuel consumption estimates for land cover types with low tree cover in South America, Sub-Saharan Africa, and Australia. We developed a new approach to estimate fuel consumption, based on FRP data from the polar-orbiting Moderate Resolution Imaging Spectroradiometer (MODIS) and the geostationary Spinning Enhanced Visible and Infrared Imager (SEVIRI) in combination with MODIS burned-area estimates. The fuel consumption estimates based on the geostationary and polar-orbiting instruments showed good agreement in terms of spatial patterns. We used field measurements of fuel consumption to constrain our results, but the large variation in fuel consumption in both space and time complicated this comparison and absolute fuel consumption estimates remained more uncertain. Spatial patterns in fuel consumption could be partly explained by vegetation productivity and fire return periods. In South America, most fires occurred in savannas with relatively long fire return periods, resulting in comparatively high fuel consumption as opposed to the more frequently burning savannas in Sub-Saharan Africa. Strikingly, we found the infrequently burning interior of Australia to have higher fuel consumption than the more productive but frequently burning savannas in northern Australia. Vegetation type also played an important role in explaining the distribution of fuel consumption, by affecting both fuel build-up rates and fire return periods. Hummock grasslands, which were responsible for a large share of Australian biomass burning, showed larger fuel build-up rates than equally productive grasslands in

The influence of weather and fuel type on the fuel composition of the area burned by forest fires in Ontario, 1996-2006.

PubMed

Podur, Justin J; Martell, David L

2009-07-01

Forest fires are influenced by weather, fuels, and topography, but the relative influence of these factors may vary in different forest types. Compositional analysis can be used to assess the relative importance of fuels and weather in the boreal forest. Do forest or wild land fires burn more flammable fuels preferentially or, because most large fires burn in extreme weather conditions, do fires burn fuels in the proportions they are available despite differences in flammability? In the Canadian boreal forest, aspen (Populus tremuloides) has been found to burn in less than the proportion in which it is available. We used the province of Ontario's Provincial Fuels Database and fire records provided by the Ontario Ministry of Natural Resources to compare the fuel composition of area burned by 594 large (>40 ha) fires that occurred in Ontario's boreal forest region, a study area some 430,000 km2 in size, between 1996 and 2006 with the fuel composition of the neighborhoods around the fires. We found that, over the range of fire weather conditions in which large fires burned and in a study area with 8% aspen, fires burn fuels in the proportions that they are available, results which are consistent with the dominance of weather in controlling large fires.

Disaster planning: the basics of creating a burn mass casualty disaster plan for a burn center.

PubMed

Kearns, Randy D; Conlon, Kathe M; Valenta, Andrea L; Lord, Graydon C; Cairns, Charles B; Holmes, James H; Johnson, Daryhl D; Matherly, Annette F; Sawyer, Dalton; Skarote, Mary Beth; Siler, Sean M; Helminiak, Radm Clare; Cairns, Bruce A

2014-01-01

In 2005, the American Burn Association published burn disaster guidelines. This work recognized that local and state assets are the most important resources in the initial 24- to 48-hour management of a burn disaster. Historical experiences suggest there is ample opportunity to improve local and state preparedness for a major burn disaster. This review will focus on the basics of developing a burn surge disaster plan for a mass casualty event. In the event of a disaster, burn centers must recognize their place in the context of local and state disaster plan activation. Planning for a burn center takes on three forms; institutional/intrafacility, interfacility/intrastate, and interstate/regional. Priorities for a burn disaster plan include: coordination, communication, triage, plan activation (trigger point), surge, and regional capacity. Capacity and capability of the plan should be modeled and exercised to determine limitations and identify breaking points. When there is more than one burn center in a given state or jurisdiction, close coordination and communication between the burn centers are essential for a successful response. Burn surge mass casualty planning at the facility and specialty planning levels, including a state burn surge disaster plan, must have interface points with governmental plans. Local, state, and federal governmental agencies have key roles and responsibilities in a burn mass casualty disaster. This work will include a framework and critical concepts any burn disaster planning effort should consider when developing future plans.

Global combustion: the connection between fossil fuel and biomass burning emissions (1997–2010)

PubMed Central

Balch, Jennifer K.; Nagy, R. Chelsea; Archibald, Sally; Moritz, Max A.; Williamson, Grant J.

2016-01-01

Humans use combustion for heating and cooking, managing lands, and, more recently, for fuelling the industrial economy. As a shift to fossil-fuel-based energy occurs, we expect that anthropogenic biomass burning in open landscapes will decline as it becomes less fundamental to energy acquisition and livelihoods. Using global data on both fossil fuel and biomass burning emissions, we tested this relationship over a 14 year period (1997–2010). The global average annual carbon emissions from biomass burning during this time were 2.2 Pg C per year (±0.3 s.d.), approximately one-third of fossil fuel emissions over the same period (7.3 Pg C, ±0.8 s.d.). There was a significant inverse relationship between average annual fossil fuel and biomass burning emissions. Fossil fuel emissions explained 8% of the variation in biomass burning emissions at a global scale, but this varied substantially by land cover. For example, fossil fuel burning explained 31% of the variation in biomass burning in woody savannas, but was a non-significant predictor for evergreen needleleaf forests. In the land covers most dominated by human use, croplands and urban areas, fossil fuel emissions were more than 30- and 500-fold greater than biomass burning emissions. This relationship suggests that combustion practices may be shifting from open landscape burning to contained combustion for industrial purposes, and highlights the need to take into account how humans appropriate combustion in global modelling of contemporary fire. Industrialized combustion is not only an important driver of atmospheric change, but also an important driver of landscape change through companion declines in human-started fires. This article is part of the themed issue ‘The interaction of fire and mankind’. PMID:27216509

Experimental measurements and numerical modeling of marginal burning in live chaparral fuel beds

Treesearch

X. Zhou; D.R. Weise; S Mahalingam

2005-01-01

An extensive experimental and numerical study was completed to analyze the marginal burning behavior of live chaparral shrub fuels that grow in the mountains of southern California. Laboratory fire spread experiments were carried out to determine the effects of wind, slope, moisture content, and fuel characteristics on marginal burning in fuel beds of common...

Mass spectra features of biomass burning boiler and coal burning boiler emitted particles by single particle aerosol mass spectrometer.

PubMed

Xu, Jiao; Li, Mei; Shi, Guoliang; Wang, Haiting; Ma, Xian; Wu, Jianhui; Shi, Xurong; Feng, Yinchang

2017-11-15

In this study, single particle mass spectra signatures of both coal burning boiler and biomass burning boiler emitted particles were studied. Particle samples were suspended in clean Resuspension Chamber, and analyzed by ELPI and SPAMS simultaneously. The size distribution of BBB (biomass burning boiler sample) and CBB (coal burning boiler sample) are different, as BBB peaks at smaller size, and CBB peaks at larger size. Mass spectra signatures of two samples were studied by analyzing the average mass spectrum of each particle cluster extracted by ART-2a in different size ranges. In conclusion, BBB sample mostly consists of OC and EC containing particles, and a small fraction of K-rich particles in the size range of 0.2-0.5μm. In 0.5-1.0μm, BBB sample consists of EC, OC, K-rich and Al_Silicate containing particles; CBB sample consists of EC, ECOC containing particles, while Al_Silicate (including Al_Ca_Ti_Silicate, Al_Ti_Silicate, Al_Silicate) containing particles got higher fractions as size increase. The similarity of single particle mass spectrum signatures between two samples were studied by analyzing the dot product, results indicated that part of the single particle mass spectra of two samples in the same size range are similar, which bring challenge to the future source apportionment activity by using single particle aerosol mass spectrometer. Results of this study will provide physicochemical information of important sources which contribute to particle pollution, and will support source apportionment activities. Copyright © 2017. Published by Elsevier B.V.

Characterization of biomass burning aerosols produced in the laboratory with a light-scattering aerosol mass spectrometer

NASA Astrophysics Data System (ADS)

Middlebrook, A. M.; Adler, G. A.; Coggon, M.; De Gouw, J. A.; Franchin, A.; Gilman, J.; Koss, A.; Krechmer, J. E.; Lamb, K.; Manfred, K.; Roberts, J. M.; Schwarz, J. P.; Sekimoto, K.; Selimovic, V.; Stockwell, C.; Wagner, N.; Warneke, C.; Washenfelder, R. A.; Womack, C.; Yokelson, R. J.; Yuan, B.

2017-12-01

During the 2016 NOAA FIREX project at the Missoula Fire Sciences Laboratory, small fires of known fuel type and properties were ignited to characterize their direct emissions with a large variety of new sampling methods. Two types of experiments were employed: sampling smoke directly from the exhaust stack throughout the lifecycle of the fires (stack burns) or sampling when the exhaust vent was closed to fill the room with smoke (room burns). For both types of burns, photo-oxidation chambers were at times used to mimic aging in the atmosphere. During all these experiments, we measured the non-refractory components of the smoke particles using an Aerodyne compact time-of-flight aerosol mass spectrometer (AMS) with a light scattering module and diluted the sample line as little as possible (usually by a factor of 10) without overwhelming our instrument. For the stack burns, our AMS was placed near the top of the exhaust stack to capture the composition and size distribution during the rapidly changing stages of the fires. We found that the chemical composition of the aerosols varied with fuel type and combustion conditions on time scales of a few minutes as the fuels went through different stages of heating and combustion. For the room burns, we obtained additional measurements with the light-scattering module aimed at understanding how well smoke particles are measured with the AMS, along with characterization of their physical properties. We will present a summary of our results, with connections to their relevance for constraining model treatments of fire emissions on the atmosphere.

Method and apparatus for controlling fuel/air mixture in a lean burn engine

DOEpatents

Kubesh, John Thomas; Dodge, Lee Gene; Podnar, Daniel James

1998-04-07

The system for controlling the fuel/air mixture supplied to a lean burn engine when operating on natural gas, gasoline, hydrogen, alcohol, propane, butane, diesel or any other fuel as desired. As specific humidity of air supplied to the lean burn engine increases, the oxygen concentration of exhaust gas discharged by the engine for a given equivalence ratio will decrease. Closed loop fuel control systems typically attempt to maintain a constant exhaust gas oxygen concentration. Therefore, the decrease in the exhaust gas oxygen concentration resulting from increased specific humidity will often be improperly attributed to an excessive supply of fuel and the control system will incorrectly reduce the amount of fuel supplied to the engine. Also, the minimum fuel/air equivalence ratio for a lean burn engine to avoid misfiring will increase as specific humidity increases. A relative humidity sensor to allow the control system to provide a more enriched fuel/air mixture at high specific humidity levels. The level of specific humidity may be used to compensate an output signal from a universal exhaust gas oxygen sensor for changing oxygen concentrations at a desired equivalence ratio due to variation in specific humidity specific humidity. As a result, the control system will maintain the desired efficiency, low exhaust emissions and power level for the associated lean burn engine regardless of the specific humidity level of intake air supplied to the lean burn engine.

Solid Fuel Burning in Steady, Strained, Premixed Flow Fields: The Graphite/Air/Methane System

NASA Technical Reports Server (NTRS)

Egolfopoulos, Fokion N.; Wu, Ming-Shin (Technical Monitor)

2000-01-01

A detailed numerical investigation was conducted on the simultaneous burning of laminar premixed CH4/air flames and solid graphite in a stagnation flow configuration. The graphite and methane were chosen for this model, given that they are practical fuels and their chemical kinetics are considered as the most reliable ones among solid and hydrocarbon fuels, respectively. The simulation was performed by solving the quasi-one-dimensional equations of mass, momentum, energy, and species. The GRI 2.1 scheme was used for the gas-phase kinetics, while the heterogeneous kinetics were described by a six-step mechanism including stable and radical species. The effects of the graphite surface temperature, the gas-phase equivalence ratio, and the aerodynamic strain rate on the graphite burning rate and NO, production and destruction mechanisms were assessed. Results indicate that as the graphite temperature increases, its burning rate as well as the NO, concentration increase. Furthermore, it was found that by increasing the strain rate, the graphite burning rate increases as a result of the augmented supply of the gas-phase reactants towards the surface, while the NO, concentration decreases as a result of the reduced residence time. The effect of the equivalence ratio on both the graphite burning rate and NO, concentration was found to be non-monotonic and strongly dependent on the graphite temperature. Comparisons between results obtained for a graphite and a chemically inert surface revealed that the chemical activity of the graphite surface can result to the reduction of NO through reactions of the CH3, CH2, CH, and N radicals with NO.

Modeling of marginal burning state of fire spread in live chaparral shrub fuel bed

Treesearch

X. Zhou; S. Mahalingam; D. Weise

2005-01-01

Prescribed burning in chaparral, currently used to manage wildland fuels and reduce wildfire hazard, is often conducted under marginal burning conditions. The relative importance of the fuel and environmental variables that determine fire spread success in chaparral fuels is not quantitatively understood. Based on extensive experimental study, a two-dimensional...

Burn Control in Fusion Reactors via Isotopic Fuel Tailoring

NASA Astrophysics Data System (ADS)

Boyer, Mark D.; Schuster, Eugenio

2011-10-01

The control of plasma density and temperature are among the most fundamental problems in fusion reactors and will be critical to the success of burning plasma experiments like ITER. Economic and technological constraints may require future commercial reactors to operate with low temperature, high-density plasma, for which the burn condition may be unstable. An active control system will be essential for stabilizing such operating points. In this work, a volume-averaged transport model for the energy and the densities of deuterium and tritium fuel ions, as well as the alpha particles, is used to synthesize a nonlinear feedback controller for stabilizing the burn condition. The controller makes use of ITER's planned isotopic fueling capability and controls the densities of these ions separately. The ability to modulate the DT fuel mix is exploited in order to reduce the fusion power during thermal excursions without the need for impurity injection. By moving the isotopic mix in the plasma away from the optimal 50:50 mix, the reaction rate is slowed and the alpha-particle heating is reduced to desired levels. Supported by the NSF CAREER award program (ECCS-0645086).

14 CFR 33.79 - Fuel burning thrust augmentor.

Code of Federal Regulations, 2012 CFR

2012-01-01

... thrust augmentor. Each fuel burning thrust augmentor, including the nozzle, must— (a) Provide cutoff of... range of operation; (d) Upon a failure or malfunction of augmentor combustion, not cause the engine to...

14 CFR 33.79 - Fuel burning thrust augmentor.

Code of Federal Regulations, 2014 CFR

2014-01-01

... thrust augmentor. Each fuel burning thrust augmentor, including the nozzle, must— (a) Provide cutoff of... range of operation; (d) Upon a failure or malfunction of augmentor combustion, not cause the engine to...

14 CFR 33.79 - Fuel burning thrust augmentor.

Code of Federal Regulations, 2010 CFR

2010-01-01

... thrust augmentor. Each fuel burning thrust augmentor, including the nozzle, must— (a) Provide cutoff of... range of operation; (d) Upon a failure or malfunction of augmentor combustion, not cause the engine to...

14 CFR 33.79 - Fuel burning thrust augmentor.

Code of Federal Regulations, 2013 CFR

2013-01-01

... thrust augmentor. Each fuel burning thrust augmentor, including the nozzle, must— (a) Provide cutoff of... range of operation; (d) Upon a failure or malfunction of augmentor combustion, not cause the engine to...

14 CFR 33.79 - Fuel burning thrust augmentor.

Code of Federal Regulations, 2011 CFR

2011-01-01

... thrust augmentor. Each fuel burning thrust augmentor, including the nozzle, must— (a) Provide cutoff of... range of operation; (d) Upon a failure or malfunction of augmentor combustion, not cause the engine to...

77 FR 18297 - Air Traffic Noise, Fuel Burn, and Emissions Modeling Using the Aviation Environmental Design Tool...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-27

... Integrated Routing System-- NIRS].'' The FAA developed the AEDT 2a to model aircraft noise, fuel burn, and... operations schedule. These data are used to compute aircraft noise, fuel burn and emissions simultaneously... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Air Traffic Noise, Fuel Burn, and...

Study of ignition, combustion, and production of harmful substances upon burning solid organic fuel at a test bench with a vortex chamber

NASA Astrophysics Data System (ADS)

Burdukov, A. P.; Chernetskiy, M. Yu.; Dekterev, A. A.; Anufriev, I. S.; Strizhak, P. A.; Greben'kov, P. Yu.

2016-01-01

Results of investigation of furnace processes upon burning of pulverized fuel at a test bench with a power of 5 MW are presented. The test bench consists of two stages with tangential air and pulverized coal feed, and it is equipped by a vibrocentrifugal mill and a disintegrator. Such milling devices have an intensive mechanical impact on solid organic fuel, which, in a number of cases, increases the reactivity of ground material. The processes of ignition and stable combustion of a mixture of gas coal and sludge (wastes of concentration plant), as well as Ekibastus coal, ground in the disintegrator, were studied at the test bench. The results of experimental burning demonstrated that preliminary fuel grinding in the disintegrator provides autothermal combustion mode even for hardly inflammable organic fuels. Experimental combustion of biomass, wheat straw with different lignin content (18, 30, 60%) after grinding in the disintegrator, was performed at the test bench in order to determine the possibility of supporting stable autothermal burning. Stable biofuel combustion mode without lighting by highly reactive fuel was achieved in the experiments. The influence of the additive GTS-Powder (L.O.M. Leaders Co., Ltd., Republic of Korea) in the solid and liquid state on reducing sulfur oxide production upon burning Mugun coal was studied. The results of experimental combustion testify that, for an additive concentration from 1 to 15% of the total mass of the burned mixture, the maximum SO2 concentration reduction in ejected gases was not more than 18% with respect to the amount for the case of burning pure coal.

40 CFR 52.280 - Fuel burning equipment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 17, 1981. (1) South Coast Air Quality Management District. (i) Rules 67, Fuel Burning Equipment, and... interfere with the attainment and maintenance of the National Ambient Air Quality Standards. (1) Mountain... attainment and maintenance of the national ambient air quality standards has not been submitted: (1...

Emulation of Condensed Fuel Flames Using a Burning Rate Emulator (BRE) in Microgravity

NASA Technical Reports Server (NTRS)

Markan, A.; Quintiere, J. G.; Sunderland, P. B.; De Ris, J. L.; Stocker, D. P.

2017-01-01

The Burning Rate Emulator (BRE) is a gaseous fuel burner developed to emulate the burning of condensed phase fuels. The current study details several tests at the NASA Glenn 5-s drop facility to test the BRE technique in microgravity conditions. The tests are conducted for two burner diameters, 25 mm and 50 mm respectively, with methane and ethylene as the fuels. The ambient pressure, oxygen content and fuel flow rate are additional parameters. The microgravity results exhibit a nominally hemispherical flame with decelerating growth and quasi-steady heat flux after about 5 seconds. The BRE burner was evaluated with a transient analysis to assess the extent of steady-state achieved. The burning rate and flame height recorded at the end of the drop are correlated using two steady-state purely diffusive models. A higher burning rate for the bigger burner as compared to theory indicates the significance of gas radiation. The effect of the ambient pressure and oxygen concentration on the heat of gasification are also examined.

Effects of Burning Alternative Fuel in a 5-Cup Combustor Sector

NASA Technical Reports Server (NTRS)

Tacina, K. M.; Chang, C. T.; Lee, C.-M.; He, Z.; Herbon, J.

2015-01-01

A goal of NASA's Environmentally Responsible Aviation (ERA) program is to develop a combustor that will reduce the NOx emissions and that can burn both standard and alternative fuels. To meet this goal, NASA partnered with General Electric Aviation to develop a 5-cup combustor sector; this sector was tested in NASA Glenn's Advanced Subsonic Combustion Rig (ASCR). To verify that the combustor sector was fuel-flexible, it was tested with a 50-50 blend of JP-8 and a biofuel made from the camelina sativa plant. Results from this test were compared to results from tests where the fuel was neat JP-8. Testing was done at three combustor inlet conditions: cruise, 30% power, and 7% power. When compared to burning JP-8, burning the 50-50 blend did not significantly affect emissions of NOx, CO, or total hydrocarbons. Furthermore, it did not significantly affect the magnitude and frequency of the dynamic pressure fluctuations.

Addition agents effects on hydrocarbon fuels burning

NASA Astrophysics Data System (ADS)

Larionov, V. M.; Mitrofanov, G. A.; Sakhovskii, A. V.

2016-01-01

Literature review on addition agents effects on hydrocarbon fuels burning has been conducted. The impact results in flame pattern and burning velocity change, energy efficiency increase, environmentally harmful NOx and CO emission reduction and damping of self-oscillations in flow. An assumption about water molecules dissociation phenomenon existing in a number of practical applications and being neglected in most explanations for physical- chemical processes taking place in case of injection of water/steam into combustion zone has been noted. The hypothesis about necessity of water dissociation account has been proposed. It can be useful for low temperature combustion process control and NOx emission reduction.

Experimental investigation of burning rates of pure ethanol and ethanol blended fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parag, Shintre; Raghavan, Vasudevan

2009-05-15

A fundamental experimental study to determine the burning rates of ethanol and ethanol-blended fossil fuels is presented. Pure liquid ethanol or its blends with liquid fossil fuels such as gasoline or diesel, has been transpired to the surface a porous sphere using an infusion pump. Burning of the fuel takes place on the surface of the porous sphere, which is placed in an air stream blowing upwards with a uniform velocity at atmospheric pressure and temperature under normal gravity conditions. At low air velocities, when ignited, a flame envelopes the sphere. For each sphere size, air stream velocity and fuelmore » type, the fuel feed rate will vary and the same is recorded as the burning rate for that configuration. The flame stand-off distances from the sphere surface are measured by post-processing the digital image of the flame photograph using suitable imaging software. The transition velocity at which the flame moves and establishes itself at the wake region of the sphere has been determined for different diameters and fuel types. Correlations of these parameters are also presented. (author)« less

Thorium Fuel Options for Sustained Transuranic Burning in Pressurized Water Reactors - 12381

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rahman, Fariz Abdul; Lee, John C.; Franceschini, Fausto

2012-07-01

As described in companion papers, Westinghouse is proposing the adoption of a thorium-based fuel cycle to burn the transuranics (TRU) contained in the current Used Nuclear Fuel (UNF) and transition towards a less radio-toxic high level waste. A combination of both light water reactors (LWR) and fast reactors (FR) is envisaged for the task, with the emphasis initially posed on their TRU burning capability and eventually to their self-sufficiency. Given the many technical challenges and development times related to the deployment of TRU burners fast reactors, an interim solution making best use of the current resources to initiate burning themore » legacy TRU inventory while developing and testing some technologies of later use is desirable. In this perspective, a portion of the LWR fleet can be used to start burning the legacy TRUs using Th-based fuels compatible with the current plants and operational features. This analysis focuses on a typical 4-loop PWR, with 17x17 fuel assembly design and TRUs (or Pu) admixed with Th (similar to U-MOX fuel, but with Th instead of U). Global calculations of the core were represented with unit assembly simulations using the Linear Reactivity Model (LRM). Several assembly configurations have been developed to offer two options that can be attractive during the TRU transmutation campaign: maximization of the TRU transmutation rate and capability for TRU multi-recycling, to extend the option of TRU recycling in LWR until the FR is available. Homogeneous as well as heterogeneous assembly configurations have been developed with various recycling schemes (Pu recycle, TRU recycle, TRU and in-bred U recycle etc.). Oxide as well as nitride fuels have been examined. This enabled an assessment of the potential for burning and multi-recycling TRU in a Th-based fuel PWR to compare against other more typical alternatives (U-MOX and variations thereof). Results will be shown indicating that Th-based PWR fuel is a promising option to multi

How the user can influence particulate emissions from residential wood and pellet stoves: Emission factors for different fuels and burning conditions

NASA Astrophysics Data System (ADS)

Fachinger, Friederike; Drewnick, Frank; Gieré, Reto; Borrmann, Stephan

2017-06-01

For a common household wood stove and a pellet stove we investigated the dependence of emission factors for various gaseous and particulate pollutants on burning phase, burning condition, and fuel. Ideal and non-ideal burning conditions (dried wood, under- and overload, small logs, logs with bark, excess air) were used. We tested 11 hardwood species (apple, ash, bangkirai, birch, beech, cherry, hickory, oak, olive, plum, sugar maple), 4 softwood species (Douglas fir, pine, spruce, spruce/fir), treated softwood, beech and oak wood briquettes, paper briquettes, brown coal, wood chips, and herbaceous species (miscanthus, Chinese silver grass) as fuel. Particle composition (black carbon, non-refractory, and some semi-refractory species) was measured continuously. Repeatability was shown to be better for the pellet stove than for the wood stove. It was shown that the user has a strong influence on wood stove emission behavior both by selection of the fuel and of the burning conditions: Combustion efficiency was found to be low at both very low and very high burn rates, and influenced particle properties such as particle number, mass, and organic content in a complex way. No marked differences were found for the emissions from different wood species. For non-woody fuels, much higher emission factors could be observed (up to five-fold increase). Strongest enhancement of emission factors was found for burning of small or dried logs (up to six-fold), and usage of excess air (two- to three-fold). Real world pellet stove emissions can be expected to be much closer to laboratory-derived emission factors than wood stove emissions, due to lower dependence on user operation.

Irradiation performance of PFBR MOX fuel after 112 GWd/t burn-up

NASA Astrophysics Data System (ADS)

Venkiteswaran, C. N.; Jayaraj, V. V.; Ojha, B. K.; Anandaraj, V.; Padalakshmi, M.; Vinodkumar, S.; Karthik, V.; Vijaykumar, Ran; Vijayaraghavan, A.; Divakar, R.; Johny, T.; Joseph, Jojo; Thirunavakkarasu, S.; Saravanan, T.; Philip, John; Rao, B. P. C.; Kasiviswanathan, K. V.; Jayakumar, T.

2014-06-01

The 500 MWe Prototype Fast Breeder Reactor (PFBR) which is in advanced stage of construction at Kalpakkam, India, will use mixed oxide (MOX) fuel with a target burnup of 100 GWd/t. The fuel pellet is of annular design to enable operation at a peak linear power of 450 W/cm with the requirement of minimum duration of pre-conditioning. The performance of the MOX fuel and the D9 clad and wrapper material was assessed through Post Irradiation Examinations (PIE) after test irradiation of 37 fuel pin subassembly in Fast Breeder Test Reactor (FBTR) to a burn-up of 112 GWd/t. Fission product distribution, swelling and fuel-clad gap evolution, central hole diameter variation, restructuring, fission gas release and clad wastage due to fuel-clad chemical interaction were evaluated through non-destructive and destructive examinations. The examinations have indicated that the MOX fuel can safely attain the desired target burn-up in PFBR.

Modelling carbonaceous aerosol from residential solid fuel burning with different assumptions for emissions

NASA Astrophysics Data System (ADS)

Ots, Riinu; Heal, Mathew R.; Young, Dominique E.; Williams, Leah R.; Allan, James D.; Nemitz, Eiko; Di Marco, Chiara; Detournay, Anais; Xu, Lu; Ng, Nga L.; Coe, Hugh; Herndon, Scott C.; Mackenzie, Ian A.; Green, David C.; Kuenen, Jeroen J. P.; Reis, Stefan; Vieno, Massimo

2018-04-01

Evidence is accumulating that emissions of primary particulate matter (PM) from residential wood and coal combustion in the UK may be underestimated and/or spatially misclassified. In this study, different assumptions for the spatial distribution and total emission of PM from solid fuel (wood and coal) burning in the UK were tested using an atmospheric chemical transport model. Modelled concentrations of the PM components were compared with measurements from aerosol mass spectrometers at four sites in central and Greater London (ClearfLo campaign, 2012), as well as with measurements from the UK black carbon network.The two main alternative emission scenarios modelled were Base4x and combRedist. For Base4x, officially reported PM2.5 from the residential and other non-industrial combustion source sector were increased by a factor of four. For the combRedist experiment, half of the baseline emissions from this same source were redistributed by residential population density to simulate the effect of allocating some emissions to the smoke control areas (that are assumed in the national inventory to have no emissions from this source). The Base4x scenario yielded better daily and hourly correlations with measurements than the combRedist scenario for year-long comparisons of the solid fuel organic aerosol (SFOA) component at the two London sites. However, the latter scenario better captured mean measured concentrations across all four sites. A third experiment, Redist - all emissions redistributed linearly to population density, is also presented as an indicator of the maximum concentrations an assumption like this could yield.The modelled elemental carbon (EC) concentrations derived from the combRedist experiments also compared well with seasonal average concentrations of black carbon observed across the network of UK sites. Together, the two model scenario simulations of SFOA and EC suggest both that residential solid fuel emissions may be higher than inventory

Effects of salvage logging and pile-and-burn on fuel loading, potential fire behaviour, fuel consumption and emissions

Treesearch

Morris C. Johnson; Jessica E. Halofsky; David L. Peterson

2013-01-01

We used a combination of field measurements and simulation modelling to quantify the effects of salvage logging, and a combination of salvage logging and pile-and-burn fuel surface fuel treatment (treatment combination), on fuel loadings, fire behaviour, fuel consumption and pollutant emissions at three points in time: post-windstorm (before salvage logging), post-...

Microstructural modeling of thermal conductivity of high burn-up mixed oxide fuel

NASA Astrophysics Data System (ADS)

Teague, Melissa; Tonks, Michael; Novascone, Stephen; Hayes, Steven

2014-01-01

Predicting the thermal conductivity of oxide fuels as a function of burn-up and temperature is fundamental to the efficient and safe operation of nuclear reactors. However, modeling the thermal conductivity of fuel is greatly complicated by the radially inhomogeneous nature of irradiated fuel in both composition and microstructure. In this work, radially and temperature-dependent models for effective thermal conductivity were developed utilizing optical micrographs of high burn-up mixed oxide fuel. The micrographs were employed to create finite element meshes with the OOF2 software. The meshes were then used to calculate the effective thermal conductivity of the microstructures using the BISON [1] fuel performance code. The new thermal conductivity models were used to calculate thermal profiles at end of life for the fuel pellets. These results were compared to thermal conductivity models from the literature, and comparison between the new finite element-based thermal conductivity model and the Duriez-Lucuta model was favorable.

Microstructural Modeling of Thermal Conductivity of High Burn-up Mixed Oxide Fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melissa Teague; Michael Tonks; Stephen Novascone

2014-01-01

Predicting the thermal conductivity of oxide fuels as a function of burn-up and temperature is fundamental to the efficient and safe operation of nuclear reactors. However, modeling the thermal conductivity of fuel is greatly complicated by the radially inhomogeneous nature of irradiated fuel in both composition and microstructure. In this work, radially and temperature-dependent models for effective thermal conductivity were developed utilizing optical micrographs of high burn-up mixed oxide fuel. The micrographs were employed to create finite element meshes with the OOF2 software. The meshes were then used to calculate the effective thermal conductivity of the microstructures using the BISONmore » fuel performance code. The new thermal conductivity models were used to calculate thermal profiles at end of life for the fuel pellets. These results were compared to thermal conductivity models from the literature, and comparison between the new finite element-based thermal conductivity model and the Duriez–Lucuta model was favorable.« less

Transuranic Waste Burning Potential of Thorium Fuel in a Fast Reactor - 12423

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wenner, Michael; Franceschini, Fausto; Ferroni, Paolo

Westinghouse Electric Company (referred to as 'Westinghouse' in the rest of this paper) is proposing a 'back-to-front' approach to overcome the stalemate on nuclear waste management in the US. In this approach, requirements to further the societal acceptance of nuclear waste are such that the ultimate health hazard resulting from the waste package is 'as low as reasonably achievable'. Societal acceptability of nuclear waste can be enhanced by reducing the long-term radiotoxicity of the waste, which is currently driven primarily by the protracted radiotoxicity of the transuranic (TRU) isotopes. Therefore, a transition to a more benign radioactive waste can bemore » accomplished by a fuel cycle capable of consuming the stockpile of TRU 'legacy' waste contained in the LWR Used Nuclear Fuel (UNF) while generating waste which is significantly less radio-toxic than that produced by the current open U-based fuel cycle (once through and variations thereof). Investigation of a fast reactor (FR) operating on a thorium-based fuel cycle, as opposed to the traditional uranium-based is performed. Due to a combination between its neutronic properties and its low position in the actinide chain, thorium not only burns the legacy TRU waste, but it does so with a minimal production of 'new' TRUs. The effectiveness of a thorium-based fast reactor to burn legacy TRU and its flexibility to incorporate various fuels and recycle schemes according to the evolving needs of the transmutation scenario have been investigated. Specifically, the potential for a high TRU burning rate, high U-233 generation rate if so desired and low concurrent production of TRU have been used as metrics for the examined cycles. Core physics simulations of a fast reactor core running on thorium-based fuels and burning an external TRU feed supply have been carried out over multiple cycles of irradiation, separation and reprocessing. The TRU burning capability as well as the core isotopic content have been

On the condition of UO2 nuclear fuel irradiated in a PWR to a burn-up in excess of 110 MWd/kgHM

NASA Astrophysics Data System (ADS)

Restani, R.; Horvath, M.; Goll, W.; Bertsch, J.; Gavillet, D.; Hermann, A.; Martin, M.; Walker, C. T.

2016-12-01

Post-irradiation examination results are presented for UO2 fuel from a PWR fuel rod that had been irradiated to an average burn-up of 105 MWd/kgHM and showed high fission gas release of 42%. The radial distribution of xenon and the partitioning of fission gas between bubbles and the fuel matrix was investigated using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and electron probe microanalysis. It is concluded that release from the fuel at intermediate radial positions was mainly responsible for the high fission gas release. In this region thermal release had occurred from the high burn-up structure (HBS) at some point after the sixth irradiation cycle. The LA-ICP-MS results indicate that gas release had also occurred from the HBS in the vicinity of the pellet periphery. It is shown that the gas pressure in the HBS pores is well below the pressure that the fuel can sustain.

Production of CO2 from Fossil Fuel Burning by Fuel Type, 1860-1982

DOE Data Explorer

Rotty, R.M. [Oak Ridge Associated Univ., Oak Ridge, TN (United States); Marland, G. [Oak Ridge Associated Univ., Oak Ridge, TN (United States)

2004-01-01

Global carbon dioxide emissions for 1950 through 1982 were estimated by Marland and Rotty (1984) from fuel production data from the U.N. Energy Statistics Yearbook (1983, 1984). Data before 1950 came from Keeling (1973). Fuel-production data were used in these calculations because they appeared to be more reliable on a global basis than fuel-consumption data. The data given are the year and annual global CO2 emissions (annual global total; cumulative global total since 1860; and annual global emissions from solid fuels, liquid fuels, natural gas, gas flaring, and cement manufacturing). These data provide the only pre-1950 estimates of the amount of carbon emitted to the atmosphere from fossil-fuel burning. The CO2 emission record since 1950 has been updated and revised several times with the most recent estimates being published by Marland et al. (1989).

Fuel Droplet Burning During Droplet Combustion Experiment

NASA Technical Reports Server (NTRS)

2003-01-01

Fuel ignites and burns in the Droplet Combustion Experiment (DCE) on STS-94 on July 4 1997, MET:2/05:40 (approximate). The DCE was designed to investigate the fundamental combustion aspects of single, isolated droplets under different pressures and ambient oxygen concentrations for a range of droplet sizes varying between 2 and 5 mm. DCE used various fuels -- in drops ranging from 1 mm (0.04 inches) to 5 mm (0.2 inches) -- and mixtures of oxidizers and inert gases to learn more about the physics of combustion in the simplest burning configuration, a sphere. The experiment elapsed time is shown at the bottom of the composite image. The DCE principal investigator was Forman Williams, University of California, San Diego. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1R mission (STS-94, July 1-17 1997). Advanced combustion experiments will be a part of investigations plarned for the International Space Station. (1.4MB, 13-second MPEG, screen 320 x 240 pixels; downlinked video, higher quality not available)A still JPG composite of this movie is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300168.html.

Fuel Burn Estimation Using Real Track Data

NASA Technical Reports Server (NTRS)

Chatterji, Gano B.

2011-01-01

A procedure for estimating fuel burned based on actual flight track data, and drag and fuel-flow models is described. The procedure consists of estimating aircraft and wind states, lift, drag and thrust. Fuel-flow for jet aircraft is determined in terms of thrust, true airspeed and altitude as prescribed by the Base of Aircraft Data fuel-flow model. This paper provides a theoretical foundation for computing fuel-flow with most of the information derived from actual flight data. The procedure does not require an explicit model of thrust and calibrated airspeed/Mach profile which are typically needed for trajectory synthesis. To validate the fuel computation method, flight test data provided by the Federal Aviation Administration were processed. Results from this method show that fuel consumed can be estimated within 1% of the actual fuel consumed in the flight test. Next, fuel consumption was estimated with simplified lift and thrust models. Results show negligible difference with respect to the full model without simplifications. An iterative takeoff weight estimation procedure is described for estimating fuel consumption, when takeoff weight is unavailable, and for establishing fuel consumption uncertainty bounds. Finally, the suitability of using radar-based position information for fuel estimation is examined. It is shown that fuel usage could be estimated within 5.4% of the actual value using positions reported in the Airline Situation Display to Industry data with simplified models and iterative takeoff weight computation.

Comparison of PM emissions from a commercial jet engine burning conventional, biomass, and Fischer-Tropsch fuels.

PubMed

Lobo, Prem; Hagen, Donald E; Whitefield, Philip D

2011-12-15

Rising fuel costs, an increasing desire to enhance security of energy supply, and potential environmental benefits have driven research into alternative renewable fuels for commercial aviation applications. This paper reports the results of the first measurements of particulate matter (PM) emissions from a CFM56-7B commercial jet engine burning conventional and alternative biomass- and, Fischer-Tropsch (F-T)-based fuels. PM emissions reductions are observed with all fuels and blends when compared to the emissions from a reference conventional fuel, Jet A1, and are attributed to fuel properties associated with the fuels and blends studied. Although the alternative fuel candidates studied in this campaign offer the potential for large PM emissions reductions, with the exception of the 50% blend of F-T fuel, they do not meet current standards for aviation fuel and thus cannot be considered as certified replacement fuels. Over the ICAO Landing Takeoff Cycle, which is intended to simulate aircraft engine operations that affect local air quality, the overall PM number-based emissions for the 50% blend of F-T fuel were reduced by 34 ± 7%, and the mass-based emissions were reduced by 39 ± 7%.

A Burning Rate Emulator (BRE) for Study in Microgravity

NASA Technical Reports Server (NTRS)

Markan, A.; Sunderland, P. B.; Quintiere, J. G.; DeRis, J.; Stocker, D. P.

2015-01-01

A gas-fueled burner, the Burning Rate Emulator (BRE), is used to emulate condensed-phase fuel flames. The design has been validated to easily measure the burning behavior of condensed-phase fuels by igniting a controlled stream of gas fuel and diluent. Four properties, including the heat of combustion, the heat of gasification, the surface temperature, and the laminar smoke point, are assumed to be sufficient to define the steady burning rate of a condensed-phase fuel. The heat of gasification of the fuel is determined by measuring the heat flux and the fuel flow rate. Microgravity BRE tests in the NASA 5.2 s drop facility have examined the burning of pure methane and ethylene (pure and 50 in N2 balance). Fuel flow rates, chamber oxygen concentration and initial pressure have been varied. Two burner sizes, 25 and 50 mm respectively, are chosen to examine the nature of initial microgravity burning. The tests reveal bubble-like flames that increase within the 5.2s drop but the heat flux received from the flame appears to asymptotically approach steady state. Portions of the methane flames appear to locally detach and extinguish at center, while its shape remains fixed, but growing. The effective heat of gasification is computed from the final measured net heat flux and the fuel flow rate under the assumption of an achieved steady burning. Heat flux (or mass flux) and flame position are compared with stagnant layer burning theory. The analysis offers the prospect of more complete findings from future longer duration ISS experiments.

Impacts of Particulate Pollution from Fossil Fuel and Biomass Burnings on the Air Quality and Human Health in Southeast Asia

NASA Astrophysics Data System (ADS)

Lee, H. H.; Iraqui, O.; Gu, Y.; Yim, S. H. L.; Wang, C.

2017-12-01

Severe haze events in Southeast Asia have attracted the attention of governments and the general public in recent years, due to their impact on local economies, air quality and public health. Widespread biomass burning activities are a major source of severe haze events in Southeast Asia. On the other hand, particulate pollutants from human activities other than biomass burning also play an important role in degrading air quality in Southeast Asia. These pollutants can be locally produced or brought in from neighboring regions by long-range transport. A better understanding of the respective contributions of fossil fuel and biomass burning aerosols to air quality degradation becomes an urgent task in forming effective air pollution mitigation policies in Southeast Asia. In this study, to examine and quantify the contributions of fossil fuel and biomass burning aerosols to air quality and visibility degradation over Southeast Asia, we conducted three numerical simulations using the Weather Research and Forecasting (WRF) model coupled with a chemistry component (WRF-Chem). These simulations were driven by different aerosol emissions from: (a) fossil fuel burning only, (b) biomass burning only, and (c) both fossil fuel and biomass burning. By comparing the simulation results, we examined the corresponding impacts of fossil fuel and biomass burning emissions, separately and combined, on the air quality and visibility of the region. The results also showed that the major contributors to low visibility days (LVDs) among 50 ASEAN cities are fossil fuel burning aerosols (59%), while biomass burning aerosols provided an additional 13% of LVDs in Southeast Asia. In addition, the number of premature mortalities among ASEAN cities has increased from 4110 in 2002 to 6540 in 2008, caused primarily by fossil fuel burning aerosols. This study suggests that reductions in both fossil fuel and biomass burning emissions are necessary to improve the air quality in Southeast Asia.

Aircraft Engine Technology for Green Aviation to Reduce Fuel Burn

NASA Technical Reports Server (NTRS)

Hughes, Christopher E.; VanZante, Dale E.; Heidmann, James D.

2013-01-01

The NASA Fundamental Aeronautics Program Subsonic Fixed Wing Project and Integrated Systems Research Program Environmentally Responsible Aviation Project in the Aeronautics Research Mission Directorate are conducting research on advanced aircraft technology to address the environmental goals of reducing fuel burn, noise and NOx emissions for aircraft in 2020 and beyond. Both Projects, in collaborative partnerships with U.S. Industry, Academia, and other Government Agencies, have made significant progress toward reaching the N+2 (2020) and N+3 (beyond 2025) installed fuel burn goals by fundamental aircraft engine technology development, subscale component experimental investigations, full scale integrated systems validation testing, and development validation of state of the art computation design and analysis codes. Specific areas of propulsion technology research are discussed and progress to date.

Fuel droplet burning rates at high pressures

NASA Technical Reports Server (NTRS)

Canada, G. S.; Faeth, G. M.

1972-01-01

Combustion of methanol, ethanol, propanol -1, n - pentane, n - heptane and n - decane was observed in air under natural convection conditions at pressures up to 100 atm. The droplets were simulated by porous spheres with diameters in the range 0.63 - 1.90 cm. The pressure levels of the tests were high enough so that near critical combustion was observed for methanol and ethanol. Measurements were made of the burning rate and liquid surface temperatures of the fuels. The data were compared with variable property analysis of the combustion process, including a correction for natural convection. The burning rate predictions of the various theories were similar and in fair agreement with the data. The high pressure theory gave the best prediction for the liquid surface temperatures of ethanol and propanol -1 at high pressure. The experiments indicated the approach of critical burning conditions for methanol and ethanol at pressures on the order of 80 - 100 atm, which was in good agreement with the predictions of both the low and high pressure analysis.

Prescribed burning and mastication effects on surface fuels in southern pine beetle-killed loblolly pine plantations

Treesearch

Aaron D. Stottlemyer; Thomas A. Waldrop; G. Geoff Wang

2015-01-01

Surface fuels were characterized in loblolly pine (Pinus taeda L.) plantations severely impacted by southern pine beetle (Dendroctonus frontalis Ehrh.) (SPB) outbreaks in the upper South Carolina Piedmont. Prescribed burning and mastication were then tested as fuel reduction treatments in these areas. Prescribed burning reduced...

Apparatus and method for burning a lean, premixed fuel/air mixture with low NOx emission

DOEpatents

Kostiuk, Larry W.; Cheng, Robert K.

1996-01-01

An apparatus for enabling a burner to stably burn a lean fuel/air mixture. The burner directs the lean fuel/air mixture in a stream. The apparatus comprises an annular flame stabilizer; and a device for mounting the flame stabilizer in the fuel/air mixture stream. The burner may include a body having an internal bore, in which case, the annular flame stabilizer is shaped to conform to the cross-sectional shape of the bore, is spaced from the bore by a distance greater than about 0.5 mm, and the mounting device mounts the flame stabilizer in the bore. An apparatus for burning a gaseous fuel with low NOx emissions comprises a device for premixing air with the fuel to provide a lean fuel/air mixture; a nozzle having an internal bore through which the lean fuel/air mixture passes in a stream; and a flame stabilizer mounted in the stream of the lean fuel/air mixture. The flame stabilizer may be mounted in the internal bore, in which case, it is shaped and is spaced from the bore as just described. In a method of burning a lean fuel/air mixture, a lean fuel/air mixture is provided, and is directed in a stream; an annular eddy is created in the stream of the lean fuel/air mixture; and the lean fuel/air mixture is ignited at the eddy.

A Burke-Schumann analysis of diffusion-flame structures supported by a burning droplet

NASA Astrophysics Data System (ADS)

Nayagam, Vedha; Dietrich, Daniel L.; Williams, Forman A.

2017-07-01

A Burke-Schumann description of three different regimes of combustion of a fuel droplet in an oxidising atmosphere, namely the premixed-flame regime, the partial-burning regime and the diffusion-flame regime, is presented by treating the fuel and oxygen leakage fractions through the flame as known parameters. The analysis shows that the burning-rate constant, the flame-standoff ratio, and the flame temperature in these regimes can be obtained from the classical droplet-burning results by suitable definitions of an effective ambient oxygen mass fraction and an effective fuel concentration in the droplet interior. The results show that increasing oxygen leakage alone through the flame lowers both the droplet burning rate and the flame temperature, whereas leakage of fuel alone leaves the burning rate unaffected while reducing the flame temperature and moving the flame closer to the droplet surface. Solutions for the partial-burning regime are shown to exist only for a limited range of fuel and oxygen leakage fractions.

Emission and chemistry of organic compounds from biomass burning: measurements from an iodide time-of-flight chemical ionization mass spectrometer (I- ToF-CIMS) during the FIREX FireLab 2016 intensive

NASA Astrophysics Data System (ADS)

Yuan, B.; Krechmer, J. E.; Warneke, C.; Coggon, M.; Koss, A.; Lim, C. Y.; Selimovic, V.; Gilman, J.; Lerner, B. M.; Stark, H.; Kang, H.; Jimenez, J. L.; Yokelson, R. J.; Liggio, J.; Roberts, J. M.; Kroll, J. H.; De Gouw, J. A.

2017-12-01

Biomass burning can emit large amounts of many different organic compounds to the atmosphere. The emission strengths of these emitted organic compounds and their subsequent atmospheric chemistry are not well known. In this study, we deployed a time-of-flight chemical ionization mass spectrometer using iodide as reagent ions (Iodide ToF-CIMS) to measure direct emissions of organic compounds during the FIREX laboratory 2016 intensive in the USDA Fire Sciences Lab in Missoula, MT. An interpretation of the I­- TOF-CIMS mass spectra from biomass burning emissions will be presented. The dependence of the emissions of selected organic compounds with fuel types, combustion efficiency and fuel chemical compositions will be discussed. The I- TOF-CIMS also measured aged biomass burning smoke from a small smog chamber and an oxidative flow reactor (OFR). The I- TOF-CIMS consistently observed much higher signals of highly oxygenated organic compounds in the aged biomass burning smoke than in fresh emissions, indicative of strong secondary formation of these organic compounds in biomass burning plumes.

A custom-tailored FAMOS burn-up meter for VVER 440 fuel assemblies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simon, G.G.; Golochtchapov, S.; Glazov, A.G.

1995-12-31

The FAMOS fuel assembly monitoring system had been originally developed for monitoring irradiated fuel assemblies of the Karlsruhe Nuclear Research Center concentrating on neutron detection systems for special applications.The measurements in the past had demonstrated that FAMOS can perform precise measurements to control or measure with accuracy the main physical parameters of spent fuel. The FAMOS 3 system is specialized for burn-up determination of fuel assemblies. Thus it is possible to take into account the burn-up for the purposes of storage and transportation. The Kola NPP VVER 440 requirements necessitated developing an especially adopted FAMOS 3 system. In addition tomore » the passive neutron measurement, a gross gamma detection and a boron concentration monitoring system are implemented. The new system was constructed as well as tested in laboratory experiments. The monitoring system has been delivered to the customer and is ready for use.« less

Nitrogen oxides from burning forest fuels examined by thermogravimetry and evolved gas analysis

Treesearch

H.B. Clements; Charles K. McMahon

1980-01-01

Abstract. Twelve forest fuels that varied widely in nitrogen content were burned in a thermogravimetric system, and nitrogen oxide production was analyzed by chemiluminescence. The effects of fuel nitrogen concentration, available oxygen, flow rate, and heating rate on nitrogen oxide production were examined.Results show that fuel nitrogen is an...

Pre-main Sequence Evolution and the Hydrogen-Burning Minimum Mass

NASA Astrophysics Data System (ADS)

Nakano, Takenori

There is a lower limit to the mass of the main-sequence stars (the hydrogen-burning minimum mass) below which the stars cannot replenish the energy lost from their surfaces with the energy released by the hydrogen burning in their cores. This is caused by the electron degeneracy in the stars which suppresses the increase of the central temperature with contraction. To find out the lower limit we need the accurate knowledge of the pre-main sequence evolution of very low-mass stars in which the effect of electron degeneracy is important. We review how Hayashi and Nakano (1963) carried out the first determination of this limit.

Gas Turbine Engine Nonvolatile Particulate Matter Mass Emissions: Correlation with Smoke Number for Conventional and Alternative Fuel Blends.

PubMed

Christie, Simon; Lobo, Prem; Lee, David; Raper, David

2017-01-17

This study evaluates the relationship between the emissions parameters of smoke number (SN) and mass concentration of nonvolatile particulate matter (nvPM) in the exhaust of a gas turbine engine for a conventional Jet A-1 and a number of alternative fuel blends. The data demonstrate the significant impact of fuel composition on the emissions and highlight the magnitude of the fuel-induced uncertainty for both SN within the Emissions Data Bank as well as nvPM mass within the new regulatory standard under development. Notwithstanding these substantial differences, the data show that correlation between SN and nvPM mass concentration still adheres to the first order approximation (FOA3), and this agreement is maintained over a wide range of fuel compositions. Hence, the data support the supposition that the FOA3 is applicable to engines burning both conventional and alternative fuel blends without adaptation or modification. The chemical composition of the fuel is shown to impact mass and number concentration as well as geometric mean diameter of the emitted nvPM; however, the data do not support assertions that the emissions of black carbon with small mean diameter will result in significant deviations from FOA3.

EBSD and TEM characterization of high burn-up mixed oxide fuel

NASA Astrophysics Data System (ADS)

Teague, Melissa; Gorman, Brian; Miller, Brandon; King, Jeffrey

2014-01-01

Understanding and studying the irradiation behavior of high burn-up oxide fuel is critical to licensing of future fast breeder reactors. Advancements in experimental techniques and equipment are allowing for new insights into previously irradiated samples. In this work dual column focused ion beam (FIB)/scanning electron microscope (SEM) was utilized to prepared transmission electron microscope samples from mixed oxide fuel with a burn-up of 6.7% FIMA. Utilizing the FIB/SEM for preparation resulted in samples with a dose rate of <0.5 mRem/h compared to ∼1.1 R/h for a traditionally prepared TEM sample. The TEM analysis showed that the sample taken from the cooler rim region of the fuel pellet had ∼2.5× higher dislocation density than that of the sample taken from the mid-radius due to the lower irradiation temperature of the rim. The dual column FIB/SEM was additionally used to prepared and serially slice ∼25 μm cubes. High quality electron back scatter diffraction (EBSD) were collected from the face at each step, showing, for the first time, the ability to obtain EBSD data from high activity irradiated fuel.

EBSD and TEM Characterization of High Burn-up Mixed Oxide Fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teague, Melissa C.; Gorman, Brian P.; Miller, Brandon D.

2014-01-01

Understanding and studying the irradiation behavior of high burn-up oxide fuel is critical to licensing of future fast breeder reactors. Advancements in experimental techniques and equipment are allowing for new insights into previously irradiated samples. In this work dual column focused ion beam (FIB)/scanning electron microscope (SEM) was utilized to prepared transmission electron microscope samples from mixed oxide fuel with a burn-up of 6.7% FIMA. Utilizing the FIB/SEM for preparation resulted in samples with a dose rate of <0.5 mRem/h compared to approximately 1.1 R/h for a traditionally prepared TEM sample. The TEM analysis showed that the sample taken frommore » the cooler rim region of the fuel pellet had approximately 2.5x higher dislocation density than that of the sample taken from the mid-radius due to the lower irradiation temperature of the rim. The dual column FIB/SEM was additionally used to prepared and serially slice approximately 25 um cubes. High quality electron back scatter diffraction (EBSD) were collected from the face at each step, showing, for the first time, the ability to obtain EBSD data from high activity irradiated fuel.« less

Simulation of differential die-away instrument’s response to asymmetrically burned spent nuclear fuel

DOE PAGES

Martinik, Tomas; Henzl, Vladimir; Grape, Sophie; ...

2015-03-04

Here, previous simulation studies of Differential Die–Away (DDA) instrument’s response to active interrogation of spent nuclear fuel from a pressurized water reactor (PWR) yielded promising results in terms of its capability to accurately measure or estimate basic spent fuel assembly (SFA) characteristics, such as multiplication, initial enrichment (IE) and burn-up (BU) as well as the total plutonium content. These studies were however performed only for a subset of idealized SFAs with a symmetric BU with respect to its longitudinal axis. Therefore, to complement the previous results, additional simulations have been performed of the DDA instrument’s response to interrogation of asymmetricallymore » burned spent nuclear fuel in order to determine whether detailed assay of SFAs from all 4 sides will be necessary in real life applications or whether a cost and time saving single sided assay could be used to achieve results of similar quality as previously reported in case of symmetrically burned SFAs.« less

Simulation of differential die-away instrument’s response to asymmetrically burned spent nuclear fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martinik, Tomas; Henzl, Vladimir; Grape, Sophie

Here, previous simulation studies of Differential Die–Away (DDA) instrument’s response to active interrogation of spent nuclear fuel from a pressurized water reactor (PWR) yielded promising results in terms of its capability to accurately measure or estimate basic spent fuel assembly (SFA) characteristics, such as multiplication, initial enrichment (IE) and burn-up (BU) as well as the total plutonium content. These studies were however performed only for a subset of idealized SFAs with a symmetric BU with respect to its longitudinal axis. Therefore, to complement the previous results, additional simulations have been performed of the DDA instrument’s response to interrogation of asymmetricallymore » burned spent nuclear fuel in order to determine whether detailed assay of SFAs from all 4 sides will be necessary in real life applications or whether a cost and time saving single sided assay could be used to achieve results of similar quality as previously reported in case of symmetrically burned SFAs.« less

Aerolization During Boron Nanoparticle Multi-Component Fuel Group Burning Studies

DTIC Science & Technology

2014-02-03

Anderson, University of Utah). …………………… 14 Figure 2. Photograph of group burning facility showing benchtop flat flame burner unit with injector nozzle ...and (B) aerosol generator. 16 Figure 6. Diagram of benchtop flat flame burner unit showing injector nozzle assembly with VOAG orifice, fuel and...translation stage, variable fuel and gas supply rates, and injector nozzles that can be configured to investigate diffusion and premixed flames (Fig. 2 & 3

Thermochemical properties of flame gases from fine wildland fuels

Treesearch

Frank A. Albini

1979-01-01

Describes a theoretical model for calculating thermochemical properties of the gaseous fuel that burns in the free flame at the edge of a spreading fire in fine forest fuels. Predicted properties are the heat of combustion, stoichiometric air/fuel mass ratio, mass-averaged temperature, and mass fraction of unburned fuel in the gas mixture emitted from the flame-...

Study of Rapid-Regression Liquefying Hybrid Rocket Fuels

NASA Technical Reports Server (NTRS)

Zilliac, Greg; DeZilwa, Shane; Karabeyoglu, M. Arif; Cantwell, Brian J.; Castellucci, Paul

2004-01-01

A report describes experiments directed toward the development of paraffin-based hybrid rocket fuels that burn at regression rates greater than those of conventional hybrid rocket fuels like hydroxyl-terminated butadiene. The basic approach followed in this development is to use materials such that a hydrodynamically unstable liquid layer forms on the melting surface of a burning fuel body. Entrainment of droplets from the liquid/gas interface can substantially increase the rate of fuel mass transfer, leading to surface regression faster than can be achieved using conventional fuels. The higher regression rate eliminates the need for the complex multi-port grain structures of conventional solid rocket fuels, making it possible to obtain acceptable performance from single-port structures. The high-regression-rate fuels contain no toxic or otherwise hazardous components and can be shipped commercially as non-hazardous commodities. Among the experiments performed on these fuels were scale-up tests using gaseous oxygen. The data from these tests were found to agree with data from small-scale, low-pressure and low-mass-flux laboratory tests and to confirm the expectation that these fuels would burn at high regression rates, chamber pressures, and mass fluxes representative of full-scale rocket motors.

Emissions of polycyclic aromatic hydrocarbons (PAH) from open burning of biomass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jenkins, B.M.

Emissions of polycyclic aromatic hydrocarbons (PAH) were measured during wind tunnel simulations of open burning for various types of biomass. The wind tunnel (Jenkins, et al., 1993) was used to simulate open fires spreading in opposition to the wind for cereal crop residues, and pile fires in agricultural and sylvicultural wood residues. Emission factors expressing the mass of pollutant species emitted per unit mass of dry fuel consumed were derived from mass balances conducted on each fire. Emission factors for primary pollutants and volatile organic species were similarly derived. Partitioning of PAH in the combustion products was investigated by determiningmore » mass fractions on particulate matter and in a downstream resin trap and other sampling train components. Yields of PAH are given for the major types of fuels and burning conditions.« less

Historical emissions of carbonaceous aerosols from biomass and fossil fuel burning for the period 1870-2000

NASA Astrophysics Data System (ADS)

Ito, Akinori; Penner, Joyce E.

2005-06-01

Historical changes of black carbon (BC) and particulate organic matter (POM) emissions from biomass burning (BB) and fossil fuel (FF) burning are estimated from 1870 to 2000. A bottom-up inventory for open vegetation (OV) burning is scaled by a top-down estimate for the year 2000. Monthly and interannual variations are derived over the time period from 1979 to 2000 based on the TOMS satellite aerosol index (AI) and this global map. Prior to 1979, emissions are scaled to a CH4 emissions inventory based on land-use change. Biofuel (BF) emissions from a recent inventory for developing countries are scaled forward and backward in time using population statistics and crop production statistics. In developed countries, wood consumption data together with emission factors for cooking and heating practices are used for biofuel estimates. For fossil fuel use, we use fuel consumption data and specific emission factors for different fuel use categories to develop an inventory over 1950-2000, and emissions are scaled to a CO2 inventory prior to that time. Technology changes for emissions from the diesel transport sector are included. During the last decade of this time period, the BC and POM emissions from biomass burning (i.e., OV + BF) contribute a significant amount to the primary sources of BC and POM and are larger than those from FF. Thus 59% of the NH BC emissions and 90% of the NH POM emissions are from BB in 2000. Fossil fuel consumption technologies are needed prior to 1990 in order to improve estimates of fossil fuel emissions during the twentieth century. These results suggest that the aerosol emissions from biomass burning need to be represented realistically in climate change assessments. The estimated emissions are available on a 1° × 1° grid for global climate modeling studies of climate changes.

Fuel mass and stand structure after post-fire logging of a severely burned ponderosa pine forest in northeastern Oregon.

Treesearch

J.D. McIver; R. Ottmar

2006-01-01

Stand structure and downed woody fuel mass were measured in four replicate units for each of three treatments (unlogged control, commercial harvest, and fuel reduction harvest) following the 1996 Summit Wildfire in northeastern Oregon. Commercial and fuel-reduction harvest resulted in a significant decrease in tree density and tree basal areas. The total downed woody...

Vertical feed stick wood fuel burning furnace system

DOEpatents

Hill, Richard C.

1982-01-01

A stove or furnace for efficient combustion of wood fuel includes a vertical feed combustion chamber (15) for receiving and supporting wood fuel in a vertical attitude or stack. A major upper portion of the combustion chamber column comprises a water jacket (14) for coupling to a source of water or heat transfer fluid for convection circulation of the fluid. The locus (31) of wood fuel combustion is thereby confined to the refractory base of the combustion chamber. A flue gas propagation delay channel (34) extending laterally from the base of the chamber affords delayed travel time in a high temperature refractory environment sufficient to assure substantially complete combustion of the gaseous products of wood burning with forced air prior to extraction of heat in heat exchanger (16). Induced draft draws the fuel gas and air mixture laterally through the combustion chamber and refractory high temperature zone to the heat exchanger and flue. Also included are active sources of forced air and induced draft, multiple circuit couplings for the recovered heat, and construction features in the refractory material substructure and metal component superstructure.

Vertical feed stick wood fuel burning furnace system

DOEpatents

Hill, Richard C.

1984-01-01

A new and improved stove or furnace for efficient combustion of wood fuel including a vertical feed combustion chamber for receiving and supporting wood fuel in a vertical attitude or stack, a major upper portion of the combustion chamber column comprising a water jacket for coupling to a source of water or heat transfer fluid and for convection circulation of the fluid for confining the locus of wood fuel combustion to the bottom of the vertical gravity feed combustion chamber. A flue gas propagation delay channel extending from the laterally directed draft outlet affords delayed travel time in a high temperature environment to assure substantially complete combustion of the gaseous products of wood burning with forced air as an actively induced draft draws the fuel gas and air mixture laterally through the combustion and high temperature zone. Active sources of forced air and induced draft are included, multiple use and circuit couplings for the recovered heat, and construction features in the refractory material substructure and metal component superstructure.

Carbon Nanostructure of Diesel Soot Particles Emitted from 2 and 4 Stroke Marine Engines Burning Different Fuels.

PubMed

Lee, Won-Ju; Park, Seul-Hyun; Jang, Se-Hyun; Kim, Hwajin; Choi, Sung Kuk; Cho, Kwon-Hae; Cho, Ik-Soon; Lee, Sang-Min; Choi, Jae-Hyuk

2018-03-01

Diesel soot particles were sampled from 2-stroke and 4-stroke engines that burned two different fuels (Bunker A and C, respectively), and the effects of the engine and fuel types on the structural characteristics of the soot particle were analyzed. The carbon nanostructures of the sampled particles were characterized using various techniques. The results showed that the soot sample collected from the 4-stroke engine, which burned Bunker C, has a higher degree of order of the carbon nanostructure than the sample collected from the 2-stroke engine, which burned Bunker A. Furthermore, the difference in the exhaust gas temperatures originating from the different engine and fuel types can affect the nanostructure of the soot emitted from marine diesel engines.

The effect of relativistic Compton scattering on thermonuclear burn of pure deuterium fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghasemizad, A.; Nazirzadeh, M.; Khanbabaei, B.

The relativistic effects of the Compton scattering on the thermonuclear burn-up of pure deuterium fuel in non-equilibrium plasma have been studied by four temperature (4T) theory. In the limit of low electron temperatures and photon energies, the nonrelativistic Compton scattering is valid and a convenient approximation, but in the high energy exchange rates between electrons and photons, is seen to break down. The deficiencies of the nonrelativistic approximation can be overcome by using the relativistic correction in the photons kinetic equation. In this research, we have utilized the four temperature (4T) theory to calculate the critical burn-up parameter for puremore » deuterium fuel, while the Compton scattering is considered as a relativistic phenomenon. It was shown that the measured critical burn-up parameter in ignition with relativistic Compton scattering is smaller than that of the parameter in the ignition with the nonrelativistic Compton scattering.« less

Reactivity loss validation of high burn-up PWR fuels with pile-oscillation experiments in MINERVE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leconte, P.; Vaglio-Gaudard, C.; Eschbach, R.

2012-07-01

The ALIX experimental program relies on the experimental validation of the spent fuel inventory, by chemical analysis of samples irradiated in a PWR between 5 and 7 cycles, and also on the experimental validation of the spent fuel reactivity loss with bum-up, obtained by pile-oscillation measurements in the MINERVE reactor. These latter experiments provide an overall validation of both the fuel inventory and of the nuclear data responsible for the reactivity loss. This program offers also unique experimental data for fuels with a burn-up reaching 85 GWd/t, as spent fuels in French PWRs never exceeds 70 GWd/t up to now.more » The analysis of these experiments is done in two steps with the APOLLO2/SHEM-MOC/CEA2005v4 package. In the first one, the fuel inventory of each sample is obtained by assembly calculations. The calculation route consists in the self-shielding of cross sections on the 281 energy group SHEM mesh, followed by the flux calculation by the Method Of Characteristics in a 2D-exact heterogeneous geometry of the assembly, and finally a depletion calculation by an iterative resolution of the Bateman equations. In the second step, the fuel inventory is used in the analysis of pile-oscillation experiments in which the reactivity of the ALIX spent fuel samples is compared to the reactivity of fresh fuel samples. The comparison between Experiment and Calculation shows satisfactory results with the JEFF3.1.1 library which predicts the reactivity loss within 2% for burn-up of {approx}75 GWd/t and within 4% for burn-up of {approx}85 GWd/t. (authors)« less

Waste burning and heat recovery characteristics of a mass burn incineration system.

PubMed

Chen, Wei-Hsin

2003-02-01

An experimental investigation on waste combustion characteristics of a mass burn incinerator is conducted in this study. Three different charging modes, including operator manipulation, periodic feeding, and temperature control, are taken into consideration. The results indicate that the burning characteristics in the combustion chambers are closely related to the operating modes. For the operator manipulation where the wastes are sent into the incinerator in two short periods, the entire temperature distribution of the primary combustion chamber can be partitioned into two parts, thereby yielding waste group combustion. Temperature oscillations in both the primary and secondary combustion chambers are characterized for the periodic feeding. However, because of the shorter charging period and smaller amount of waste, the burning interaction between the two chambers is initially weak and becomes notable in the final stage. When temperature control is performed, the burning oscillation of the primary combustion chamber is further amplified so the combustion interaction is drastic. These exhibitions are mainly caused by the competition between endothermic and exothermic reactions. The instantaneous heat exchange efficiency of the cyclone heat recovery system (CHRS) installed in the incineration system is also evaluated to obtain details of energy recovery behaviors. As a result, the efficiency tends to decrease linearly with increasing temperature of hot flue gas. This arises from the fact that heat loss from the gas to the environment is increased when the temperature of the former is higher, even though the temperature gradient across the cyclone is enlarged.

Environmentally Responsible Aviation: Propulsion Research to Enable Fuel Burn, Noise and Emissions Reduction

NASA Technical Reports Server (NTRS)

Van Zante, Dale; Suder, Kenneth

2015-01-01

The NASA Environmentally Responsible Aviation (ERA) program is maturing technologies to enable simultaneous reduction of fuel burn, noise and emissions from an aircraft engine system. Three engine related Integrated Technology Demonstrations (ITDs) have been completed at Glenn Research Center in collaboration with Pratt Whitney, General Electric and the Federal Aviation Administration. The engine technologies being matured are: a low NOx, fuel flexible combustor in partnership with Pratt Whitney; an ultra-high bypass, ducted propulsor system in partnership with Pratt Whitney and FAA; and high pressure ratio, front-stage core compressor technology in partnership with General Electric. The technical rationale, test configurations and overall results from the test series in each ITD are described. ERA is using system analysis to project the benefits of the ITD technologies on potential aircraft systems in the 2025 timeframe. Data from the ITD experiments were used to guide the system analysis assumptions. Results from the current assessments for fuel burn, noise and oxides of nitrogen emissions are presented.

Environmentally Responsible Aviation: Propulsion Research to Enable Fuel Burn, Noise and Emissions Reduction

NASA Technical Reports Server (NTRS)

Van Zante, Dale E.; Suder, Kenneth L.

2015-01-01

The NASA Environmentally Responsible Aviation (ERA) program is maturing technologies to enable simultaneous reduction of fuel burn, noise and emissions from an aircraft engine system. Three engine related Integrated Technology Demonstrations (ITDs) have been completed at Glenn Research Center in collaboration with Pratt Whitney, General Electric and the Federal Aviation Administration. The engine technologies being matured are a low NOx, fuel flexible combustor in partnership with Pratt Whitney, an ultra-high bypass, ducted propulsor system in partnership with Pratt Whitney FAA and high pressure ratio, front-stage core compressor technology in partnership with General Electric. The technical rationale, test configurations and overall results from the test series in each ITD are described. ERA is using system analysis to project the benefits of the ITD technologies on potential aircraft systems in the 2025 timeframe. Data from the ITD experiments were used to guide the system analysis assumptions. Results from the current assessments for fuel burn, noise and oxides of nitrogen emissions are presented.

Utilizing NASA Airborne Data to Investigate the Influence of Fuel Type on Biomass Burning Aerosol Properties

NASA Astrophysics Data System (ADS)

Odwuor, A.; Corr, C.; Griffin, R. J.; Pusede, S.; Anderson, B.; Beyersdorf, A. J.; Campuzano Jost, P.; Chen, G.; Day, D. A.; Diskin, G. S.; Jimenez, J. L.; Moore, R.; Nault, B.; Schwarz, J. P.; Shook, M.; Thornhill, K. L., II; Winstead, E.; Armin, W.; Ziemba, L. D.

2017-12-01

Climate models and satellite aerosol classification retrievals rely on well-characterized aerosol optical properties (e.g., scattering and absorption coefficients) that vary with aerosol type. However, generalized parameterizations of aerosol optical properties are weakened by actual variability in aerosol chemical and physical properties that arises from factors independent of aerosol source (e.g., meteorology). This is particularly true for biomass burning (BB) aerosol, which can vary in composition and size depending on burn conditions (e.g., smoldering versus flaming) and fuel. This work investigates the relationships between BB aerosol chemical, physical, and optical properties and fuel. We compare BB aerosol measured in fire plumes associated with distinct fuel types sampled during three NASA airborne research campaigns: boreal forest fires during the Arctic Research of the Troposphere from Aircraft and Satellites (ARCTAS) mission in Saskatchewan, Canada in July 2008; agricultural fires during the Studies of Emissions and Atmospheric Composition, Clouds, and Climate Coupling by Regional Surveys (SEAC4RS) over the continental U.S. in August/September 2013; and scrubland fires during the Student Airborne Research Program (SARP) mission in Southern California, U.S. in June 2016. Mean modified combustion efficiency values between 0.9 and 0.92 for the agricultural plumes and between 0.92 and 0.99 for the boreal and scrubland plumes indicate a significant flaming component to these fires. Despite similarities in burn conditions, SSA at 550nm was consistently lower for the agricultural and scrubland fires ( 0.92) compared to the boreal forest ( 0.96). While the ratio of black carbon to organic aerosol (OA) was similar among fires, differences in the OA were noted; f44/f60 ratios derived from Aerosol Mass Spectrometer OA measurements were consistently higher (>5) in scrubland and agricultural fires compared to boreal forest fires (<5). This suggests the amount of

Fuel reduction and coarse woody debris dynamics with early season and late season prescribed fire in a Sierra Nevada mixed conifer forest

USGS Publications Warehouse

Knapp, E.E.; Keeley, J.E.; Ballenger, E.A.; Brennan, T.J.

2005-01-01

Fire exclusion has led to an unnatural accumulation and greater spatial continuity of organic material on the ground in many forests. This material serves both as potential fuel for forest fires and habitat for a large array of forest species. Managers must balance fuel reduction to reduce wildfire hazard with fuel retention targets to maintain other forest functions. This study reports fuel consumption and changes to coarse woody debris attributes with prescribed burns ignited under different fuel moisture conditions. Replicated early season burn, late season burn, and unburned control plots were established in old-growth mixed conifer forest in Sequoia National Park that had not experienced fire for more than 120 years. Early season burns were ignited during June 2002 when fuels were relatively moist, and late season burns were ignited during September/October 2001 when fuels were dry. Fuel loading and coarse woody debris abundance, cover, volume, and mass were evaluated prior to and after the burns. While both types of burns reduced fuel loading, early season burns consumed significantly less of the total dead and down organic matter than late season burns (67% versus 88%). This difference in fuel consumption between burning treatments was significant for most all woody fuel components evaluated, plus the litter and duff layers. Many logs were not entirely consumed - therefore the number of logs was not significantly changed by fire - but burning did reduce log length, cover, volume, and mass. Log cover, volume, and mass were reduced to a lesser extent by early season burns than late season burns, as a result of higher wood moisture levels. Early season burns also spread over less of the ground surface within the burn perimeter (73%) than late season burns (88%), and were significantly patchier. Organic material remaining after a fire can dam sediments and reduce erosion, while unburned patches may help mitigate the impact of fire on fire-sensitive species by

Determination of wood burning and fossil fuel contribution of black carbon at Delhi, India using aerosol light absorption technique.

PubMed

Tiwari, S; Pipal, A S; Srivastava, A K; Bisht, D S; Pandithurai, G

2015-02-01

A comprehensive measurement program of effective black carbon (eBC), fine particle (PM2.5), and carbon monoxide (CO) was undertaken during 1 December 2011 to 31 March 2012 (winter period) in Delhi, India. The mean mass concentrations of eBC, PM2.5, and CO were recorded as 12.1 ± 8.7 μg/m(3), 182.75 ± 114.5 μg/m(3), and 3.41 ± 1.6 ppm, respectively, during the study period. Also, the absorption Angstrom exponent (AAE) was estimated from eBC and varied from 0.38 to 1.29 with a mean value of 1.09 ± 0.11. The frequency of occurrence of AAE was ~17 % less than unity whereas ~83 % greater than unity was observed during the winter period in Delhi. The mass concentrations of eBC were found to be higher by ~34 % of the average value of eBC (12.1 μg/m(3)) during the study period. Sources of eBC were estimated, and they were ~94 % from fossil fuel (eBCff) combustion whereas only 6 % was from wood burning (eBCwb). The ratio between eBCff and eBCwb was 15, which indicates a higher impact from fossil fuels compared to biomass burning. When comparing eBCff during day and night, a factor of three higher concentrations was observed in nighttime than daytime, and it is due to combustion of fossil fuel (diesel vehicle emission) and shallow boundary layer conditions. The contribution of eBCwb in eBC was higher between 1800 and 2100 hours due to burning of wood/biomass. A significant correlation between eBC and PM2.5 (r = 0.78) and eBC and CO (r = 0.46) indicates the similarity in location sources. The mass concentration of eBC was highest (23.4 μg/m(3)) during the month of December when the mean visibility (VIS) was lowest (1.31 km). Regression analysis among wind speed (WS), VIS, soot particles, and CO was studied, and significant negative relationships were seen between VIS and eBC (-0.65), eBCff (-0.66), eBCwb (-0.34), and CO (-0.65); however, between WS and eBC (-0.68), eBCff (-0.67), eBCwb (-0.28), and CO (-0.53). The regression analysis indicated

Relative importance of fuel management, ignition management and weather for area burned: Evidence from five landscape-fire-succession models

Treesearch

Geoffrey J. Cary; Mike D. Flannigan; Robert E. Keane; Ross A. Bradstock; Ian D. Davies; James M. Lenihan; Chao Li; Kimberley A. Logan; Russell A. Parsons

2009-01-01

The behaviour of five landscape fire models (CAFE, FIRESCAPE, LAMOS(HS), LANDSUM and SEMLAND) was compared in a standardised modelling experiment. The importance of fuel management approach, fuel management effort, ignition management effort and weather in determining variation in area burned and number of edge pixels burned (a measure of potential impact on assets...

Experimental Methodology for Estimation of Local Heat Fluxes and Burning Rates in Steady Laminar Boundary Layer Diffusion Flames.

PubMed

Singh, Ajay V; Gollner, Michael J

2016-06-01

Modeling the realistic burning behavior of condensed-phase fuels has remained out of reach, in part because of an inability to resolve the complex interactions occurring at the interface between gas-phase flames and condensed-phase fuels. The current research provides a technique to explore the dynamic relationship between a combustible condensed fuel surface and gas-phase flames in laminar boundary layers. Experiments have previously been conducted in both forced and free convective environments over both solid and liquid fuels. A unique methodology, based on the Reynolds Analogy, was used to estimate local mass burning rates and flame heat fluxes for these laminar boundary layer diffusion flames utilizing local temperature gradients at the fuel surface. Local mass burning rates and convective and radiative heat feedback from the flames were measured in both the pyrolysis and plume regions by using temperature gradients mapped near the wall by a two-axis traverse system. These experiments are time-consuming and can be challenging to design as the condensed fuel surface burns steadily for only a limited period of time following ignition. The temperature profiles near the fuel surface need to be mapped during steady burning of a condensed fuel surface at a very high spatial resolution in order to capture reasonable estimates of local temperature gradients. Careful corrections for radiative heat losses from the thermocouples are also essential for accurate measurements. For these reasons, the whole experimental setup needs to be automated with a computer-controlled traverse mechanism, eliminating most errors due to positioning of a micro-thermocouple. An outline of steps to reproducibly capture near-wall temperature gradients and use them to assess local burning rates and heat fluxes is provided.

Effects of prescribed burning on vegetation and fuel loading in three east Texas state parks

Treesearch

Sandra Rideout; Brian P. Oswald

2002-01-01

This study was conducted to evaluate the initial effectiveness of prescribed burning in the ecological restoration of forests within selected parks in east Texas. Twenty-four permanent plots were installed to monitor fuel loads, overstory, sapling, seedling, shrub and herbaceous layers within burn and control units of Mission Tejas, Tyler and Village Creek state parks...

Noise and Fuel Burn Reduction Potential of an Innovative Subsonic Transport Configuration

NASA Technical Reports Server (NTRS)

Guo, Yueping; Nickol, Craig L.; Thomas, Russell H.

2014-01-01

A study is presented for the noise and fuel burn reduction potential of an innovative double deck concept aircraft with two three-shaft direct-drive turbofan engines. The engines are mounted from the fuselage so that the engine inlet is over the main wing. It is shown that such an aircraft can achieve a cumulative Effective Perceived Noise Level (EPNL) about 28 dB below the current aircraft noise regulations of Stage 4. The combination of high bypass ratio engines and advanced wing design with laminar flow control technologies provide fuel burn reduction and low noise levels simultaneously. For example, the fuselage mounted engine position provides more than 4 EPNLdB of noise reduction by shielding the inlet radiated noise. To identify the potential effect of noise reduction technologies on this concept, parametric studies are presented to reveal the system level benefits of various emerging noise reduction concepts, for both engine and airframe noise reduction. These concepts are discussed both individually to show their respective incremental noise reduction potential and collectively to assess their aggregate effects on the total noise. Through these concepts approximately about 8 dB of additional noise reduction is possible, bringing the cumulative noise level of this aircraft to 36 EPNLdB below Stage 4, if the entire suite of noise reduction technologies would mature to practical application. In a final step, an estimate is made for this same aircraft concept but with higher bypass ratio, geared, turbofan engines. With this geared turbofan propulsion system, the noise is estimated to reach as low as 40-42 dB below Stage 4 with a fuel burn reduction of 43-47% below the 2005 best-in-class aircraft baseline. While just short of the NASA N+2 goals of 42 dB and 50% fuel burn reduction, for a 2025 in service timeframe, this assessment shows that this innovative concept warrants refined study. Furthermore, this design appears to be a viable potential future passenger

BEHAVE: fire behavior prediction and fuel modeling system-BURN Subsystem, part 1

Treesearch

Patricia L. Andrews

1986-01-01

Describes BURN Subsystem, Part 1, the operational fire behavior prediction subsystem of the BEHAVE fire behavior prediction and fuel modeling system. The manual covers operation of the computer program, assumptions of the mathematical models used in the calculations, and application of the predictions.

Emissions of nitrogen-containing organic compounds from the burning of herbaceous and arboraceous biomass: Fuel composition dependence and the variability of commonly used nitrile tracers

NASA Astrophysics Data System (ADS)

Coggon, Matthew M.; Veres, Patrick R.; Yuan, Bin; Koss, Abigail; Warneke, Carsten; Gilman, Jessica B.; Lerner, Brian M.; Peischl, Jeff; Aikin, Kenneth C.; Stockwell, Chelsea E.; Hatch, Lindsay E.; Ryerson, Thomas B.; Roberts, James M.; Yokelson, Robert J.; Gouw, Joost A.

2016-09-01

Volatile organic compounds (VOCs) emitted from residential wood and crop residue burning were measured in Colorado, U.S. When compared to the emissions from crop burning, residential wood burning exhibited markedly lower concentrations of acetonitrile, a commonly used biomass burning tracer. For both herbaceous and arboraceous fuels, the emissions of nitrogen-containing VOCs (NVOCs) strongly depend on the fuel nitrogen content; therefore, low NVOC emissions from residential wood burning result from the combustion of low-nitrogen fuel. Consequently, the emissions of compounds hazardous to human health, such as HNCO and HCN, and the formation of secondary pollutants, such as ozone generated by NOx, are likely to depend on fuel nitrogen. These results also demonstrate that acetonitrile may not be a suitable tracer for domestic burning in urban areas. Wood burning emissions may be best identified through analysis of the emissions profile rather than reliance on a single tracer species.

Fuel treatments and landform modify landscape patterns of burn severity in an extreme fire event

Treesearch

Susan J. Prichard; Maureen C. Kennedy

2014-01-01

Under a rapidly warming climate, a critical management issue in semiarid forests of western North America is how to increase forest resilience to wildfire. We evaluated relationships between fuel reduction treatments and burn severity in the 2006 Tripod Complex fires, which burned over 70 000 ha of mixed-conifer forests in the North Cascades range of Washington State...

Particulate Matter Stack Emission Compliance Test Procedure for Fuel Burning Units.

ERIC Educational Resources Information Center

West Virginia Air Pollution Control Commission, Charleston.

This publication details the particulate matter emissions test procedure that is applicable for conducting compliance tests for fuel burning units required to be tested under Sub-section 7 of Regulation II (1972) as established by the state of West Virginia Air Pollution Control Commission. The testing procedure is divided into five parts:…

Experimental Methodology for Estimation of Local Heat Fluxes and Burning Rates in Steady Laminar Boundary Layer Diffusion Flames

PubMed Central

Singh, Ajay V.; Gollner, Michael J.

2016-01-01

Modeling the realistic burning behavior of condensed-phase fuels has remained out of reach, in part because of an inability to resolve the complex interactions occurring at the interface between gas-phase flames and condensed-phase fuels. The current research provides a technique to explore the dynamic relationship between a combustible condensed fuel surface and gas-phase flames in laminar boundary layers. Experiments have previously been conducted in both forced and free convective environments over both solid and liquid fuels. A unique methodology, based on the Reynolds Analogy, was used to estimate local mass burning rates and flame heat fluxes for these laminar boundary layer diffusion flames utilizing local temperature gradients at the fuel surface. Local mass burning rates and convective and radiative heat feedback from the flames were measured in both the pyrolysis and plume regions by using temperature gradients mapped near the wall by a two-axis traverse system. These experiments are time-consuming and can be challenging to design as the condensed fuel surface burns steadily for only a limited period of time following ignition. The temperature profiles near the fuel surface need to be mapped during steady burning of a condensed fuel surface at a very high spatial resolution in order to capture reasonable estimates of local temperature gradients. Careful corrections for radiative heat losses from the thermocouples are also essential for accurate measurements. For these reasons, the whole experimental setup needs to be automated with a computer-controlled traverse mechanism, eliminating most errors due to positioning of a micro-thermocouple. An outline of steps to reproducibly capture near-wall temperature gradients and use them to assess local burning rates and heat fluxes is provided. PMID:27285827

Droplet burning at zero G

NASA Technical Reports Server (NTRS)

Williams, F. A.

1978-01-01

Questions of the importance and feasibility of performing experiments on droplet burning at zero gravity in Spacelab were studied. Information on the physics and chemistry of droplet combustion, with attention directed specifically to the chemical kinetics, heat and mass transfer, and fluid mechanics of the phenomena involved, are presented. The work was divided into three phases, the justification, the feasibility, and the conceptual development of a preliminary design. Results from the experiments performed revealed a few new facts concerning droplet burning, notably burning rates in excess of theoretical prediction and a phenomenon of flash extinction, both likely traceable to accumulation of carbon produced by gas-phase pyrolysis in the fuel-rich zone enclosed by the reaction surface. These experiments also showed that they were primarily due to timing difficulties.

FIREX-Related Biomass Burning Research Using ARM Single-Particle Soot Photometer Field Campaign Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onasch, Timothy B; Sedlacek, Arthur J

The scientific focus of this study was to investigate and quantify the mass loadings, chemical compositions, and optical properties of biomass burning particulate emissions generated in the laboratory from Western U.S. fuels using a similar instrument suite to the one deployed on the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility Gulfstream-1 (G-1) aircraft during the 2013 Biomass Burning Observation Project (BBOP) field study (Kleinman and Sedlacek, 2013). We deployed the single-particle soot photometer (SP2) to make measurements of biomass burning refractory black carbon (rBC) mass loadings and size distributions to correlate with non-refractory particulate mattermore » (NR-PM; i.e., HR-AMS) and rBC (SP-AMS) measurements as a function of photo-oxidation processes in an environmental chamber. With these measurements, we will address the following scientific questions: 1. What are the emission indices (g/kg fuel) of rBC from various wildland fuels from the Pacific Northwest (i.e., relevant to BBOP analysis) as a function of combustion conditions and simulated atmospheric processing in an environmental chamber? 2. What are the optical properties (e.g., mass-specific absorption cross-section [MAC], single-scattering albedo [SSA], and absorption Angstrom exponent [AAE)] of rBC emitted from various wildland fuels and how are they impacted by atmospheric processing? 3. How does the mixing state of rBC in biomass-burning plumes relate to the optical properties? 4. How does the emitted rBC affect radiative forcing?« less

Enhancement of acidic gases in biomass burning impacted air masses over Canada

NASA Technical Reports Server (NTRS)

Lefer, B. L.; Talbot, R. W.; Harriss, R. C.; Bradshaw, J. D.; Sandholm, S. T.; Olson, J. O.; Sachse, G. W.; Collins, J.; Shipham, M. A.; Blake, D. R.

1994-01-01

Biomass-burning impacted air masses sampled over central and eastern Canada during the summer of 1990 as part of ABLE 3B contained enhanced mixing ratios of gaseous HNO3, HCOOH, CH3COOH, and what appears to be (COOH)2. These aircraft-based samples were collected from a variety of fresh burning plumes and more aged haze layers from different source regions. Values of the enhancement factor, delta X/delta CO, where X represents an acidic gas, for combustion-impacted air masses sampled both near and farther away from the fires, were relatively uniform. However, comparison of carboxylic acid emission ratios measured in laboratory fires to field plume enhancement factors indicates significant in-plume production of HCOOH. Biomass-burning appears to be an important source of HNO3, HCOOH, and CH3COOH to the troposphere over subarctic Canada.

Shrub resprouting response after fuel reduction treatments: comparison of prescribed burning, clearing and mastication.

PubMed

Fernández, Cristina; Vega, José A; Fonturbel, Teresa

2013-03-15

Fuel reduction treatments are commonly used to reduce the risk of severe wildfire. However, more information about the effects on plant resprouting is needed to help land managers select the most appropriate treatment. To address this question, we evaluated the resprouting ability of five shrub species after the application of different types of fuel reduction methods (prescribed burning, clearing and mastication) in two contrasting shrubland areas in northern Spain. The shrub species were Erica australis, Pterospartum tridentatum and Halimium lasianthum spp. alyssoides, Ulex gallii and Erica cinerea. For most of the species under study (E. australis, P. tridentatum, H. lasianthum spp. alyssoides and U. gallii), neither plant mortality nor the number nor length of sprouted shoots per plant differed between treatments, although in E. cinerea the number of shoots was more negatively affected by prescribed burning than by clearing or mastication. The pre-treatment plant size did not affect plant mortality or plant resprouting response, suggesting that this parameter alone is not a good indicator of plant resprouting after fuel reduction treatments. Stem minimum diameter after treatments, a proxy of treatment severity, was not related to plant mortality, number or length of resprouted shoots. The duration of temperatures higher than 300 °C during burning in plant crown had a negative effect on the length of resprouted shoots, only in E. cinerea. The results show that fuel reduction treatments did not prevent shrub response in any case. Some reflections on the applicability of treatments are discussed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Contributions from transport, solid fuel burning and cooking to primary organic aerosols in two UK cities

NASA Astrophysics Data System (ADS)

Allan, J. D.; Williams, P. I.; Morgan, W. T.; Martin, C. L.; Flynn, M. J.; Lee, J.; Nemitz, E.; Phillips, G. J.; Gallagher, M. W.; Coe, H.

2010-01-01

Organic matter frequently represents the single largest fraction of fine particulates in urban environments and yet the exact contributions from different sources and processes remain uncertain, owing in part to its substantial chemical complexity. Positive Matrix Factorisation (PMF) has recently proved to be a powerful tool for the purposes of source attribution and profiling when applied to ambient organic aerosol data from the Aerodyne Aerosol Mass Spectrometer (AMS). Here we present PMF analysis applied to AMS data from UK cities for the first time. Three datasets are analysed, with the focus on objectivity and consistency. The data were collected in London during the Regent's Park and Tower Environmental Experiment (REPARTEE) intensives and Manchester. These occurred during the autumn and wintertime, such that the primary fraction would be prominent. Ambiguities associated with rotationality within sets of potential solutions are explored and the most appropriate solution sets selected based on comparisons with external data. In addition to secondary organic aerosols, three candidate sources of primary organic aerosol (POA) were identified according to mass spectral and diurnal profiles; traffic emissions, cooking and solid fuel burning (for space heating). Traffic represented, on average, 40% of POA during colder conditions and exhibited a hydrocarbon-like mass spectrum similar to those previously reported. Cooking aerosols represented 34% of POA and through laboratory work, their profile was matched with that sampled from the heating of seed oils, rather than previously-published spectra derived from charbroiling. This suggests that in these locations, oil from frying may have contributed more to the particulate than the meat itself. Solid fuel aerosols represented 26% of POA during cold weather conditions but were not discernable during the first REPARTEE campaign, when conditions were warmer than the other campaigns. This factor showed features associated

Data summary of municipal solid waste management alternatives. Volume 3, Appendix A: Mass burn technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

This appendix on Mass Burn Technologies is the first in a series designed to identify, describe and assess the suitability of several currently or potentially available generic technologies for the management of municipal solid waste (MSW). These appendices, which cover eight core thermoconversion, bioconversion and recycling technologies, reflect public domain information gathered from many sources. Representative sources include: professional journal articles, conference proceedings, selected municipality solid waste management plans and subscription technology data bases. The information presented is intended to serve as background information that will facilitate the preparation of the technoeconomic and life cycle mass, energy and environmental analysesmore » that are being developed for each of the technologies. Mass burn has been and continues to be the predominant technology in Europe for the management of MSW. In the United States, the majority of the existing waste-to-energy projects utilize this technology and nearly 90 percent of all currently planned facilities have selected mass burn systems. Mass burning generally refers to the direct feeding and combustion of municipal solid waste in a furnace without any significant waste preprocessing. The only materials typically removed from the waste stream prior to combustion are large bulky objects and potentially hazardous or undesirable wastes. The technology has evolved over the last 100 or so years from simple incineration to the most highly developed and commercially proven process available for both reducing the volume of MSW and for recovering energy in the forms of steam and electricity. In general, mass burn plants are considered to operate reliably with high availability.« less

Effects of oblique air flow on burning rates of square ethanol pool fires.

PubMed

Tao, Changfa; He, Yaping; Li, Yuan; Wang, Xishi

2013-09-15

The effects of downward airflow on the burning rate and/or burning intensity of square alcohol pool fires for different airflow speeds and directions have been studied experimentally in an inclined wind tunnel. An interesting flame-wrapping phenomenon, caused by impingement of air flow, was observed. The mass burning intensity was found to increase with the airflow speed and the impinging angle. The fuel pan rim temperatures were also measured to study the effect of wind direction and speed on heat transfer from the flame to the fuel source. A model based on heat transfer analysis was developed to correlate the burning intensity with the pan rim characteristic temperature. A good correlation was established between the model results and the experimental results. Copyright © 2013 Elsevier B.V. All rights reserved.

Burning experiments and late Paleozoic high O2 levels

NASA Astrophysics Data System (ADS)

Wildman, R.; Essenhigh, R.; Berner, R.; Hickey, L.; Wildman, C.

2003-04-01

The Paleozoic rise of land plants brought about increased burial of organic matter and a resulting increase in atmospheric oxygen concentrations. Levels as high as 30-35% O2 may have been reached during the Permo-Carboniferous (Berner and Canfield, 1989; Berner, 2001). However, burning experiments based solely on paper (Watson, 1978) have challenged these results, the claim being that if the oxygen made up more than 25% of the atmosphere, the frequency and intensity of forest fires would increase sufficiently to prevent the continued existence of plant life. Thus, since plants have persisted, it is possible that fires served as a negative feedback against excessive oxygen levels. An initial study of Paleozoic wildfire behavior via thermogravimetric analysis (TGA) was conducted under ambient and enriched oxygen conditions to simulate present and ancient atmospheres. The tests focused on natural fuels, specifically tree leaves and wood, tree fern fibers, and sphagnum peat-moss, simulating Permo-Carboniferous upland and swampland ecosystems, respectively. Three conclusions are: (1) enriched oxygen increases the rate of mass loss during burning; (2) fuel chemistry (cellulose vs. lignin) influences burning patterns; and (3) in geometrically heterogeneous fuels, geometry affects burning rate significantly. Both geometrically and chemically, paper resists fire poorly; thus, we found that it loses its mass at lower temperatures than forest materials and is therefore a poor proxy for Paleozoic ecosystems. Further study of Paleozoic wildfire spread behavior is currently being conducted. Fires are lit using pine dowels, which allow for reproducible fuel density. Steady-state, one-dimensional flame-spread is measured with thermocouples anchored two inches above the fuel bed. Both oxygen concentration of the air supply to the fire and moisture content of the fuels are varied, as we suspect that these are two main controls of wildfire spread. Burning fuels of varying moisture

Burning Fossil Fuels: Impact of Climate Change on Health.

PubMed

Sommer, Alfred

2016-01-01

A recent, sophisticated granular analysis of climate change in the United States related to burning fossil fuels indicates a high likelihood of dramatic increases in temperature, wet-bulb temperature, and precipitation, which will dramatically impact the health and well-being of many Americans, particularly the young, the elderly, and the poor and marginalized. Other areas of the world, where they lack the resources to remediate these weather impacts, will be even more greatly affected. Too little attention is being paid to the impending health impact of accumulating greenhouse gases. © The Author(s) 2015.

High Temperature Reactor (HTR) Deep Burn Core and Fuel Analysis: Design Selection for the Prismatic Block Reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Francesco Venneri; Chang-Keun Jo; Jae-Man Noh

2010-09-01

The Deep Burn (DB) Project is a U.S. Department of Energy sponsored feasibility study of Transuranic Management using high burnup fuel in the high temperature helium cooled reactor (HTR). The DB Project consists of seven tasks: project management, core and fuel analysis, spent fuel management, fuel cycle integration, TRU fuel modeling, TRU fuel qualification, and HTR fuel recycle. In the Phase II of the Project, we conducted nuclear analysis of TRU destruction/utilization in the HTR prismatic block design (Task 2.1), deep burn fuel/TRISO microanalysis (Task 2.3), and synergy with fast reactors (Task 4.2). The Task 2.1 covers the core physicsmore » design, thermo-hydraulic CFD analysis, and the thermofluid and safety analysis (low pressure conduction cooling, LPCC) of the HTR prismatic block design. The Task 2.3 covers the analysis of the structural behavior of TRISO fuel containing TRU at very high burnup level, i.e. exceeding 50% of FIMA. The Task 4.2 includes the self-cleaning HTR based on recycle of HTR-generated TRU in the same HTR. Chapter IV contains the design and analysis results of the 600MWth DB-HTR core physics with the cycle length, the average discharged burnup, heavy metal and plutonium consumptions, radial and axial power distributions, temperature reactivity coefficients. Also, it contains the analysis results of the 450MWth DB-HTR core physics and the analysis of the decay heat of a TRU loaded DB-HTR core. The evaluation of the hot spot fuel temperature of the fuel block in the DB-HTR (Deep-Burn High Temperature Reactor) core under full operating power conditions are described in Chapter V. The investigated designs are the 600MWth and 460MWth DB-HTRs. In Chapter VI, the thermo-fluid and safety of the 600MWth DB-HTRs has been analyzed to investigate a thermal-fluid design performance at the steady state and a passive safety performance during an LPCC event. Chapter VII describes the analysis results of the TRISO fuel microanalysis of the 600MWth

Elimination of fuel pressure fluctuation and multi-injection fuel mass deviation of high pressure common-rail fuel injection system

NASA Astrophysics Data System (ADS)

Li, Pimao; Zhang, Youtong; Li, Tieshuan; Xie, Lizhe

2015-03-01

The influence of fuel pressure fluctuation on multi-injection fuel mass deviation has been studied a lot, but the fuel pressure fluctuation at injector inlet is still not eliminated efficiently. In this paper, a new type of hydraulic filter consisting of a damping hole and a chamber is developed for elimination of fuel pressure fluctuation and multi-injection fuel mass deviation. Linear model of the improved high pressure common-rail system(HPCRS) including injector, the pipe connecting common-rail with injector and the hydraulic filter is built. Fuel pressure fluctuation at injector inlet, on which frequency domain analysis is conducted through fast Fourier transformation, is acquired at different target pressure and different damping hole diameter experimentally. The linear model is validated and can predict the natural frequencies of the system. Influence of damping hole diameter on fuel pressure fluctuation is analyzed qualitatively based on the linear model, and it can be inferred that an optimal diameter of the damping hole for elimination of fuel pressure fluctuation exists. Fuel pressure fluctuation and fuel mass deviation under different damping hole diameters are measured experimentally, and it is testified that the amplitude of both fuel pressure fluctuation and fuel mass deviation decreases first and then increases with the increasing of damping hole diameter. The amplitude of main injection fuel mass deviation can be reduced by 73% at most under pilot-main injection mode, and the amplitude of post injection fuel mass deviation can be reduced by 92% at most under main-post injection mode. Fuel mass of a single injection increases with the increasing of the damping hole diameter. The hydraulic filter proposed by this research can be potentially used to eliminate fuel pressure fluctuation at injector inlet and improve the stability of HPCRS fuel injection.

The national Fire and Fire Surrogate study: Effects of fuel reduction methods on forest vegetation structure and fuels

USGS Publications Warehouse

Schwilk, D.W.; Keeley, J.E.; Knapp, E.E.; Mciver, J.; Bailey, J. D.; Fettig, C.J.; Fiedler, C.E.; Harrod, R.J.; Moghaddas, J.J.; Outcalt, K.W.; Skinner, C.N.; Stephens, S.L.; Waldrop, T.A.; Yaussy, D.A.; Youngblood, A.

2009-01-01

Changes in vegetation and fuels were evaluated from measurements taken before and after fuel reduction treatments (prescribed fire, mechanical treatments, and the combination of the two) at 12 Fire and Fire Surrogate (FFS) sites located in forests with a surface fire regime across the conterminous United States. To test the relative effectiveness of fuel reduction treatments and their effect on ecological parameters we used an informationtheoretic approach on a suite of 12 variables representing the overstory (basal area and live tree, sapling, and snag density), the understory (seedling density, shrub cover, and native and alien herbaceous species richness), and the most relevant fuel parameters for wildfire damage (height to live crown, total fuel bed mass, forest floor mass, and woody fuel mass). In the short term (one year after treatment), mechanical treatments were more effective at reducing overstory tree density and basal area and at increasing quadratic mean tree diameter. Prescribed fire treatments were more effective at creating snags, killing seedlings, elevating height to live crown, and reducing surface woody fuels. Overall, the response to fuel reduction treatments of the ecological variables presented in this paper was generally maximized by the combined mechanical plus burning treatment. If the management goal is to quickly produce stands with fewer and larger diameter trees, less surface fuel mass, and greater herbaceous species richness, the combined treatment gave the most desirable results. However, because mechanical plus burning treatments also favored alien species invasion at some sites, monitoring and control need to be part of the prescription when using this treatment. ?? 2009 by the Ecological Society of America.

Reliability of biomass burning estimates from savanna fires: Biomass burning in northern Australia during the 1999 Biomass Burning and Lightning Experiment B field campaign

NASA Astrophysics Data System (ADS)

Russell-Smith, Jeremy; Edwards, Andrew C.; Cook, Garry D.

2003-02-01

This paper estimates the two-daily extent of savanna burning and consumption of fine (grass and litter) fuels from an extensive 230,000 km2 region of northern Australia during August-September 1999 encompassing the Australian continental component of the Biomass Burning and Lightning Experiment B (BIBLE B) campaign [, 2002]. The extent of burning for the study region was derived from fire scar mapping of imagery from the advanced very high resolution radiometer (AVHRR) on board the National Oceanic and Atmospheric Administration (NOAA) satellite. The mapping was calibrated and verified with reference to one Landsat scene and associated aerial transect validation data. Fine fuel loads were estimated using published fuel accumulation relationships for major regional fuel types. It is estimated that more than 43,000 km2 was burnt during the 25 day study period, with about 19 Mt of fine (grass and litter) fuels. This paper examines assumptions and errors associated with these estimates. It is estimated from uncalibrated fire mapping derived from AVHRR imagery that 417,500 km2 of the northern Australian savanna was burnt in 1999, of which 136,405 km2, or 30%, occurred in the Northern Territory study region. Using generalized fuel accumulation equations, such biomass burning consumed an estimated 212.3 Mt of fine fuels, but no data are available for consumption of coarse fuels. This figure exceeds a recent estimate, based on fine fuels only, for the combined Australian savanna and temperate grassland biomass burning over the period 1990-1999 but is lower than past estimates derived from classification approaches. We conclude that (1) fire maps derived from coarse-resolution optical imagery can be applied relatively reliably to estimate the extent of savanna fires, generally with 70-80% confidence using the approach adopted here, over the major burning period in northern Australia and (2) substantial further field assessment and associated modeling of fuel accumulation

Reduction in biomass burning aerosol light absorption upon humidification: roles of inorganically-induced hygroscopicity, particle collapse, and photoacoustic heat and mass transfer

NASA Astrophysics Data System (ADS)

Lewis, K. A.; Arnott, W. P.; Moosmüller, H.; Chakrabarty, R. K.; Carrico, C. M.; Kreidenweis, S. M.; Day, D. E.; Malm, W. C.; Laskin, A.; Jimenez, J. L.; Ulbrich, I. M.; Huffman, J. A.; Onasch, T. B.; Trimborn, A.; Liu, L.; Mishchenko, M. I.

2009-11-01

Smoke particle emissions from the combustion of biomass fuels typical for the western and southeastern United States were studied and compared under high humidity and ambient conditions in the laboratory. The fuels used were Montana ponderosa pine (Pinus ponderosa), southern California chamise (Adenostoma fasciculatum), and Florida saw palmetto (Serenoa repens). Information on the non-refractory chemical composition of biomass burning aerosol from each fuel was obtained with an aerosol mass spectrometer and through estimation of the black carbon concentration from light absorption measurements at 870 nm. Changes in the optical and physical particle properties under high humidity conditions were observed for hygroscopic smoke particles containing substantial inorganic mass fractions that were emitted from combustion of chamise and palmetto fuels. Light scattering cross sections increased under high humidity for these particles, consistent with the hygroscopic growth measured for 100 nm particles in HTDMA measurements. Photoacoustic measurements of aerosol light absorption coefficients revealed a 20% reduction with increasing relative humidity, contrary to the expectation of light absorption enhancement by the liquid coating taken up by hygroscopic particles. This reduction is hypothesized to arise from two mechanisms: (1) shielding of inner monomers after particle consolidation or collapse with water uptake; (2) the lower case contribution of mass transfer through evaporation and condensation at high relative humidity (RH) to the usual heat transfer pathway for energy release by laser-heated particles in the photoacoustic measurement of aerosol light absorption. The mass transfer contribution is used to evaluate the fraction of aerosol surface covered with liquid water solution as a function of RH.

Reduction in biomass burning aerosol light absorption upon humidification: roles of inorganically-induced hygroscopicity, particle collapse, and photoacoustic heat and mass transfer

NASA Astrophysics Data System (ADS)

Lewis, K. A.; Arnott, W. P.; Moosmüller, H.; Chakrabarty, R. K.; Carrico, C. M.; Kreidenweis, S. M.; Day, D. E.; Malm, W. C.; Laskin, A.; Jimenez, J. L.; Ulbrich, I. M.; Huffman, J. A.; Onasch, T. B.; Trimborn, A.; Liu, L.; Mishchenko, M. I.

2009-07-01

Smoke particle emissions from the combustion of biomass fuels typical for the western and southeastern United States were studied and compared under high humidity and ambient conditions in the laboratory. The fuels used are Montana ponderosa pine (Pinus ponderosa), southern California chamise (Adenostoma fasciculatum), and Florida saw palmetto (Serenoa repens). Information on the non-refractory chemical composition of biomass burning aerosol from each fuel was obtained with an aerosol mass spectrometer and through estimation of the black carbon concentration from light absorption measurements at 870 nm. Changes in the optical and physical particle properties under high humidity conditions were observed for hygroscopic smoke particles containing substantial inorganic mass fractions that were emitted from combustion of chamise and palmetto fuels. Light scattering cross sections increased under high humidity for these particles, consistent with the hygroscopic growth measured for 100 nm particles in HTDMA measurements. Photoacoustic measurements of aerosol light absorption coefficients reveal a 20% reduction with increasing relative humidity, contrary to the expectation of light absorption enhancement by the liquid coating taken up by hygroscopic particles. This reduction is hypothesized to arise from two mechanisms: 1. Shielding of inner monomers after particle consolidation or collapse with water uptake; 2. The contribution of mass transfer through evaporation and condensation at high relative humidity to the usual heat transfer pathway for energy release by laser-heated particles in the photoacoustic measurement of aerosol light absorption. The mass transfer contribution is used to evaluate the fraction of aerosol surface covered with liquid water solution as a function of RH.

Volatile organic compounds (VOCs) from biomass burning: GC-MS analysis of primary combustion emissions of fuels common to North America

NASA Astrophysics Data System (ADS)

Gilman, J.; De Gouw, J. A.; Coggon, M.; Koss, A.; Lerner, B. M.; Roberts, J. M.; Selimovic, V.; Sekimoto, K.; Yokelson, R. J.; Yuan, B.; Warneke, C.

2017-12-01

Biomass burning (BB), both natural and human-caused, is a significant source of atmospheric gases and particles. Combustion of biomass releases a complex variety of carbon-containing gases called volatile organic compounds (VOCs) that may adversely affect air quality and climate. Here we present results from the first phase of Fire Influence on Regional and Global Environments Experiment (FIREX) that was conducted at the USDA Fire Sciences Laboratory in Missoula, Montana in the fall of 2016. The goal of these laboratory experiments were to measure primary combustion emissions of fuels common to Northwestern U.S. and Canada using a variety of state-of-the-art analytical instrumentation. The data presented here utilizes a custom-built gas chromatography - mass spectrometry (GC-MS) instrument to characterize C2-C12 VOCs via in-situ sampling as well as offline analysis of diluted smoke samples stored in electropolished stainless steel whole air samplers (WAS). This analysis focuses on identifying VOCs that are (i) biomass burning and/or fuel-specific tracers, (ii) air toxics and (iii) highly-reactive VOCs that are potential precursors for photochemical ozone and/or organic aerosol formation. Of particular interest, is the identification and characterization of VOC tracers that may be useful for biomass burning specific photochemical clocks such as furan and nitrile-based molecules. Comparison of concurrently collected in-situ and whole air samples of diluted smoke will be used to identify potential sampling artefacts associated with WAS intended for use in the upcoming FIREX NOAA WP-3D research flights in 2019.

Comparison of heat transfer and soil impacts of air curtain burner burning and slash pile burning

Treesearch

Woongsoon Jang; Deborah S. Page-Dumroese; Han-Sup Han

2017-01-01

We measured soil heating and subsequent changes in soil properties between two forest residue disposal methods: slash pile burning (SPB) and air curtain burner (ACB). The ACB consumes fuels more efficiently and safely via blowing air into a burning container. Five burning trials with different fuel sizes were implemented in northern California, USA. Soil temperature...

Sectoral combustor for burning low-BTU fuel gas

DOEpatents

Vogt, Robert L.

1980-01-01

A high-temperature combustor for burning low-BTU coal gas in a gas turbine is disclosed. The combustor includes several separately removable combustion chambers each having an annular sectoral cross section and a double-walled construction permitting separation of stresses due to pressure forces and stresses due to thermal effects. Arrangements are described for air-cooling each combustion chamber using countercurrent convective cooling flow between an outer shell wall and an inner liner wall and using film cooling flow through liner panel grooves and along the inner liner wall surface, and for admitting all coolant flow to the gas path within the inner liner wall. Also described are systems for supplying coal gas, combustion air, and dilution air to the combustion zone, and a liquid fuel nozzle for use during low-load operation. The disclosed combustor is fully air-cooled, requires no transition section to interface with a turbine nozzle, and is operable at firing temperatures of up to 3000.degree. F. or within approximately 300.degree. F. of the adiabatic stoichiometric limit of the coal gas used as fuel.

Experimental study and large eddy simulation of effect of terrain slope on marginal burning in shrub fuel beds

Treesearch

Xiangyang Zhou; Shankar Mahalingam; David Weise

2007-01-01

This paper presents a combined study of laboratory scale fire spread experiments and a three-dimensional large eddy simulation (LES) to analyze the effect of terrain slope on marginal burning behavior in live chaparral shrub fuel beds. Line fire was initiated in single species fuel beds of four common chaparral plants under various fuel bed configurations and ambient...

Emissions of volatile organic compounds from maize residue open burning in the northern region of Thailand

NASA Astrophysics Data System (ADS)

Sirithian, Duanpen; Thepanondh, Sarawut; Sattler, Melanie L.; Laowagul, Wanna

2018-03-01

Emission factors for speciated volatile organic compounds (VOCs) from maize residue burning were determined in this study based on chamber experiments. Thirty-six VOC species were identified by Gas Chromatography/Mass Spectrometer (GC/MS). They were classified into six groups, including alkanes, alkenes, oxygenated VOCs, halogenated VOCs, aromatics and other. The emission factor for total VOCs was estimated as about 148 mg kg-1 dry mass burned. About 68.4% of the compounds were aromatics. Field samplings of maize residues were conducted to acquire the information of fuel characteristics including fuel loading, fraction of maize residues that were actually burned as well as proximate and elemental analysis of maize residues. The emission factors were then applied to estimate speciated VOC emissions from maize residue open burning at the provincial level in the upper-northern region of Thailand for the year 2014. Total burned area of maize covered an area of about 500,000 ha which was about 4.7% of the total area of upper-northern region of the country. It was found that total VOC emissions released during the burning season (January-April) was about 79.4 tons. Ethylbenzene, m,p-xylene, 1,2,4-trimethylbenzene, acetaldehyde and o-xylene were the major contributors, accounting for more than 65% of total speciated VOC emissions.

Chemical mass balance source apportionment of TSP in a lignite-burning area of Western Macedonia, Greece

NASA Astrophysics Data System (ADS)

Samara, Constantini

Total suspended particle mass concentrations (TSP) were determined in the Kozani-Ptolemais-Florina basin (western Macedonia, Greece), an area with intensive lignite burning for power generation. The study was conducted over a 1-year period (November 2000-November 2001) at 10 receptor sites located at variable distances from the power plants. Ambient TSP samples were analyzed for 27 major, minor and trace elements. Particulate emissions were also collected from a variety of sources including fly ash, lignite dust, automobile traffic, domestic heating, and open-air burning of agricultural biomass and refuse, and analyzed for the same chemical components. Ambient and source chemical profiles were used for source identification and apportionment of TSP by employing a chemical mass balance (CMB) receptor model. Diesel burning in vehicular traffic and in the power plants for generator start up was found to be the major contributor to ambient TSP levels at all 10 sites. Other sources with significant contributions were domestic coal burning, vegetative burning (wood combustion and agricultural burns) and refuse open-air burning. Fly ash escaping the electrostatic precipitators of the power plants was a minor contributor to ambient TSP.

Multiple burn fuel-optimal orbit transfers: Numerical trajectory computation and neighboring optimal feedback guidance

NASA Technical Reports Server (NTRS)

Chuang, C.-H.; Goodson, Troy D.; Ledsinger, Laura A.

1995-01-01

This report describes current work in the numerical computation of multiple burn, fuel-optimal orbit transfers and presents an analysis of the second variation for extremal multiple burn orbital transfers as well as a discussion of a guidance scheme which may be implemented for such transfers. The discussion of numerical computation focuses on the use of multivariate interpolation to aid the computation in the numerical optimization. The second variation analysis includes the development of the conditions for the examination of both fixed and free final time transfers. Evaluations for fixed final time are presented for extremal one, two, and three burn solutions of the first variation. The free final time problem is considered for an extremal two burn solution. In addition, corresponding changes of the second variation formulation over thrust arcs and coast arcs are included. The guidance scheme discussed is an implicit scheme which implements a neighboring optimal feedback guidance strategy to calculate both thrust direction and thrust on-off times.

Mass chemical casualties: treatment of 41 patients with burns by anhydrous ammonia.

PubMed

Zhang, Fang; Zheng, Xing-Feng; Ma, Bing; Fan, Xiao-Ming; Wang, Guang-Yi; Xia, Zhao-Fan

2015-09-01

This article reports a chemical burn incident that occurred on 31 August 2013 in Shanghai. We describe situations at the scene, emergency management, triage, evacuation, and follow-up of the victims. The scene of the incident and information on the 41 victims of this industrial chemical incident were investigated. The emergency management, triage, evacuation, and hospitalization data of the patients were summarized. At the time of the incident, 58 employees were working in a closed refrigerator workshop, 41 of whom sustained burns following the leakage of anhydrous ammonia. Ten victims died of severe inhalation injury at the scene, and another five victims died during the process of evacuation to the nearest hospital. After receiving information on the incident, a contingency plan for the burn disaster was launched immediately, and a first-aid group and an emergency and triage group were dispatched by the Changhai Hospital to the scene to aid the medical organization, emergency management, triage, and evacuation. All casualties were first rushed to the nearest hospital by ambulance. The six most serious patients with inhalation injuries were evacuated to the Changhai Hospital and admitted to the burn intensive care unit (BICU) for further treatment, one of whom died of respiratory failure and pulmonary infection. This mass casualty incident of anhydrous ammonia leakage caused potential devastating effects to the society, especially to the victims and their families. Early first-aid organization, emergency management, triage, and evacuation were of paramount importance, especially rapid evaluation of the severity of inhalation injury, and subsequent corresponding medical treatment. The prognosis of ammonia burns was poor and the sequelae were severe. Management and treatment lessons were drawn from this mass casualty chemical burn incident. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

DEUTERIUM BURNING IN MASSIVE GIANT PLANETS AND LOW-MASS BROWN DWARFS FORMED BY CORE-NUCLEATED ACCRETION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bodenheimer, Peter; D'Angelo, Gennaro; Lissauer, Jack J.

Using detailed numerical simulations, we study the formation of bodies near the deuterium-burning limit according to the core-nucleated giant planet accretion scenario. The objects, with heavy-element cores in the range 5-30 M{sub Circled-Plus }, are assumed to accrete gas up to final masses of 10-15 Jupiter masses (M{sub Jup}). After the formation process, which lasts 1-5 Myr and which ends with a ''cold-start'', low-entropy configuration, the bodies evolve at constant mass up to an age of several Gyr. Deuterium burning via proton capture is included in the calculation, and we determined the mass, M{sub 50}, above which more than 50%more » of the initial deuterium is burned. This often-quoted borderline between giant planets and brown dwarfs is found to depend only slightly on parameters, such as core mass, stellar mass, formation location, solid surface density in the protoplanetary disk, disk viscosity, and dust opacity. The values for M{sub 50} fall in the range 11.6-13.6 M{sub Jup}, in agreement with previous determinations that do not take the formation process into account. For a given opacity law during the formation process, objects with higher core masses form more quickly. The result is higher entropy in the envelope at the completion of accretion, yielding lower values of M{sub 50}. For masses above M{sub 50}, during the deuterium-burning phase, objects expand and increase in luminosity by one to three orders of magnitude. Evolutionary tracks in the luminosity versus time diagram are compared with the observed position of the companion to Beta Pictoris.« less

Reestablishing Open Rotor as an Option for Significant Fuel Burn Improvements

NASA Technical Reports Server (NTRS)

Van Zante, Dale

2011-01-01

A low-noise open rotor system is being tested in collaboration with General Electric and CFM International, a 50/50 joint company between Snecma and GE. Candidate technologies for lower noise will be investigated as well as installation effects such as pylon integration. Current test status is presented as well as future scheduled testing which includes the FAA/CLEEN test entry. Pre-test predictions show that Open Rotors have the potential for revolutionary fuel burn savings.

Influence of body mass index on skin grafting in pediatric burns.

PubMed

Sharp, Nicole E; Thomas, Priscilla G; Sherman, Ashley K; St Peter, Shawn D; Juang, David

2015-03-01

There is heterogeneous literature on the association of obese and underweight body habitus on burn outcomes in adult and pediatric literature. We examine the effect of standardized pediatric body mass index (BMI) categories skin graft utilisation. A retrospective chart review was performed on children who underwent burn treatment from January 1995 to November 2011. BMI was categorized by standard definitions: underweight (<5%), normal (5-85%), overweight (85-95%), obese (>95%). There were 1164 patients: 77 underweight, 604 normal, 215 overweight, and 268 obese patients. No differences existed between group demographics. Grafts were performed in 39% of underweight, 27% of normal, 22% of overweight, and 27% of obese patients. Underweight children had nearly a 2 fold increase in their risk of full thickness burns and were 1.8 times more likely to undergo skin grafting than normal BMI children. Overweight children had a significant decrease in the incidence skin grafting by 23% then compared to normal weight children. There were no differences in percent TBSA burned or percent TBSA grafted using ANOVA. Underweight pediatric burn victims have an increased risk for skin grafting while mildly overweight children are slightly protected from skin grafting. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

Characterization of Emissions from Heaters Burning Leaded Diesel Fuel in Unvented Tents

DTIC Science & Technology

1999-06-01

ultrafine particles . On the other hand, emissions from burning liquid fuels can be substantial in terms of both gas pollutants and particles. For...2.5) and the distribution of ultrafine particles can be estimated. The real-time particle and gas concentration can also be monitored. The...heaters produced fine and ultrafine particles . 19 Chemical Elemental Analysis Twenty-seven test runs were made under the various conditions. The air

Vortex combustor for low NOX emissions when burning lean premixed high hydrogen content fuel

DOEpatents

Steele, Robert C; Edmonds, Ryan G; Williams, Joseph T; Baldwin, Stephen P

2012-11-20

A trapped vortex combustor. The trapped vortex combustor is configured for receiving a lean premixed gaseous fuel and oxidant stream, where the fuel includes hydrogen gas. The trapped vortex combustor is configured to receive the lean premixed fuel and oxidant stream at a velocity which significantly exceeds combustion flame speed in a selected lean premixed fuel and oxidant mixture. The combustor is configured to operate at relatively high bulk fluid velocities while maintaining stable combustion, and low NOx emissions. The combustor is useful in gas turbines in a process of burning synfuels, as it offers the opportunity to avoid use of diluent gas to reduce combustion temperatures. The combustor also offers the possibility of avoiding the use of selected catalytic reaction units for removal of oxides of nitrogen from combustion gases exiting a gas turbine.

Vortex combustor for low NOx emissions when burning lean premixed high hydrogen content fuel

DOEpatents

Steele, Robert C [Woodinville, WA; Edmonds, Ryan G [Renton, WA; Williams, Joseph T [Kirkland, WA; Baldwin, Stephen P [Winchester, MA

2009-10-20

A trapped vortex combustor. The trapped vortex combustor is configured for receiving a lean premixed gaseous fuel and oxidant stream, where the fuel includes hydrogen gas. The trapped vortex combustor is configured to receive the lean premixed fuel and oxidant stream at a velocity which significantly exceeds combustion flame speed in a selected lean premixed fuel and oxidant mixture. The combustor is configured to operate at relatively high bulk fluid velocities while maintaining stable combustion, and low NOx emissions. The combustor is useful in gas turbines in a process of burning synfuels, as it offers the opportunity to avoid use of diluent gas to reduce combustion temperatures. The combustor also offers the possibility of avoiding the use of selected catalytic reaction units for removal of oxides of nitrogen from combustion gases exiting a gas turbine.

Characterization and cytotoxicity of PAHs in PM2.5 emitted from residential solid fuel burning in the Guanzhong Plain, China.

PubMed

Sun, Jian; Shen, Zhenxing; Zeng, Yaling; Niu, Xinyi; Wang, Jinhui; Cao, Junji; Gong, Xuesong; Xu, Hongmei; Wang, Taobo; Liu, Hongxia; Yang, Liu

2018-05-28

The emission factors (EFs) of polycyclic aromatic hydrocarbons (PAHs) in PM 2.5 were measured from commonly used stoves and fuels in the rural Guanzhong Plain, China. The toxicity of the PM 2.5 also was measured using in vitro cellular tests. EFs of PAHs varied from 0.18 mg kg -1 (maize straw charcoal burning in a clean stove) to 83.3 mg kg -1 (maize straw burning in Heated Kang). The two largest influencing factors on PAH EFs were air supply and volatile matter proportion in fuel. Improvements in these two factors could decrease not only EFs of PAHs but also the proportion of 3-ring to 5-ring PAHs. Exposure to PM 2.5 extracts caused a concentration-dependent decline in cell viability but an increase in reactive oxygen species (ROS), tumor necrosis factor a (TNF-α) and interleukin 6 (IL-6). PM 2.5 emitted from maize burning in Heated Kang showed the highest cytotoxicity, and EFs of ROS and inflammatory factors were the highest as well. In comparison, maize straw charcoal burning in a clean stove showed the lowest cytotoxicity, which indicated a clean stove and fuel treatment were both efficient methods for reducing cytotoxicity of primary PM 2.5 . The production of these bioreactive factors were highly correlated with 3-ring and 4-ring PAHs. Specifically, pyrene, anthracene and benzo(a)anthracene had the highest correlations with ROS production (R = 0.85, 0.81 and 0.80, respectively). This study shows that all tested stoves emitted PM 2.5 that was cytotoxic to human cells; thus, there may be no safe levels of exposure to PM 2.5 emissions from cooking and heating stoves using solid fuels. The study may also provide a new approach for evaluating the cytotoxicity of primary emitted PM 2.5 from solid fuel burning as well as other PM 2.5 sources. Copyright © 2018 Elsevier Ltd. All rights reserved.

Reductions in Emissions of Carbonaceous Particulate Matter and Polycyclic Aromatic Hydrocarbons from Combustion of Biomass Pellets in Comparisonwith Raw Fuel Burning

PubMed Central

SHEN, Guofeng; TAO, Shu; WEI, Siye; ZHANG, Yanyan; WANG, Rong; WANG, Bin; LI, Wei; SHEN, Huizhong; HUANG, Ye; CHEN, Yuanchen; CHEN, Han; YANG, Yifeng; WANG, Wei; WEI, Wen; WANG, Xilong; LIU, Wenxing; WANG, Xuejun; SIMONICH, Staci L. Massey

2012-01-01

Biomass pellets are emerging as a cleaner alternative to traditional biomass fuels. The potential benefits of using biomass pellets include improving energy utilization efficiency and reducing emissions of air pollutants. To assess the environmental, climate, and health significance of replacing traditional fuels with biomass pellets, it is critical to measure the emission factors (EFs) of various pollutants from pellet burning. However, only a few field measurements have been conducted on the emissions of carbon monoxide (CO), particulate matter (PM), and polycyclic aromatic hydrocarbons (PAHs) from the combustion of pellets. In this study, pine wood and corn straw pellets were burned in a pellet burner (2.6 kW) and the EFs of CO, organic carbon, elemental carbon, PM, and PAHs (EFCO, EFOC, EFEC, EFPM, and EFPAH) were determined. The average EFCO, EFOC, EFEC, and EFPM were 1520±1170, 8.68±11.4, 11.2±8.7, and 188±87 mg/MJ for corn straw pellets, and 266±137, 5.74±7.17, 2.02±1.57, and 71.0±54.0 mg/MJ for pine wood pellets, respectively. Total carbonaceous carbon constituted 8 to 14% of the PM mass emitted. The measured values of EFPAH for the two pellets were 1.02±0.64 and 0.506±0.360 mg/MJ, respectively. The secondary side air supply in the pellet burner did not change the EFs of most pollutants significantly (p > 0.05). The only exceptions were EFOC and EFPM for pine wood pellets because of reduced combustion temperatures with the increased air supply. In comparison with EFs for the raw pine wood and corn straw, EFCO, EFOC, EFEC, and EFPM for pellets were significantly lower than those for raw fuels (p < 0.05). However, the differences in EFPAH were not significant (p > 0.05). Based on the measured EFs and thermal efficiencies, it was estimated that 95, 98, 98, 88, and 71% reductions in the total emissions of CO, OC, EC, PM, and PAHs could be achieved by replacing the raw biomass fuels combusted in traditional cooking stoves with pellets burned in modern

Photos for estimating fuel loadings before and after prescribed burning in the upper coastal plain of the southeast

Treesearch

Eric R. Scholl; Thomas A. Waldrop

1999-01-01

Although prescribed burning is common in the Southeastern United States, most fuel models apply to only western forests. This paper documents a fuel classification system that was developed for plantations of loblolly and longleaf pines for the Upper Coastal Plain region. Multivariate analysis of variance and discriminant function analysis were used to confirm eight...

Burning by prescription in chaparral

Treesearch

Lisle R. Green

1981-01-01

Prescribed burning is frequently suggested for reducing conflagration costs in chaparral. Preparation for a prescribed burn includes environmental impact reports, approval by higher levels of authority, and a burn plan. After objectives are stated, the prescription can be written. Elements of the burn prescription reflect fuel, weather, and other factors that determine...

Rates of post-fire vegetation recovery and fuel accumulation as a function of burn severity and time-since-burn in four western U.S. ecosystems

USDA-ARS?s Scientific Manuscript database

Vegetation recovery and fuel accumulation rates following wildfire are useful measures of ecosystem resilience, yet few studies have quantified these variables over 10 years post-fire. Conventional wisdom is that recovery time to pre-fire condition will be slower as a function of burn severity, as i...

Fuel Burn Estimation Model

NASA Technical Reports Server (NTRS)

Chatterji, Gano

2011-01-01

Conclusions: Validated the fuel estimation procedure using flight test data. A good fuel model can be created if weight and fuel data are available. Error in assumed takeoff weight results in similar amount of error in the fuel estimate. Fuel estimation error bounds can be determined.

Fluidized-Solid-Fuel Injection Process

NASA Technical Reports Server (NTRS)

Taylor, William

1992-01-01

Report proposes development of rocket engines burning small grains of solid fuel entrained in gas streams. Main technical discussion in report divided into three parts: established fluidization technology; variety of rockets and rocket engines used by nations around the world; and rocket-engine equation. Discusses significance of specific impulse and ratio between initial and final masses of rocket. Concludes by stating three important reasons to proceed with new development: proposed engines safer; fluidized-solid-fuel injection process increases variety of solid-fuel formulations used; and development of fluidized-solid-fuel injection process provides base of engineering knowledge.

Quantitative Surface Emissivity and Temperature Measurements of a Burning Solid Fuel Accompanied by Soot Formation

NASA Technical Reports Server (NTRS)

Piltch, Nancy D.; Pettegrew, Richard D.; Ferkul, Paul; Sacksteder, K. (Technical Monitor)

2001-01-01

Surface radiometry is an established technique for noncontact temperature measurement of solids. We adapt this technique to the study of solid surface combustion where the solid fuel undergoes physical and chemical changes as pyrolysis proceeds, and additionally may produce soot. The physical and chemical changes alter the fuel surface emissivity, and soot contributes to the infrared signature in the same spectral band as the signal of interest. We have developed a measurement that isolates the fuel's surface emissions in the presence of soot, and determine the surface emissivity as a function of temperature. A commercially available infrared camera images the two-dimensional surface of ashless filter paper burning in concurrent flow. The camera is sensitive in the 2 to 5 gm band, but spectrally filtered to reduce the interference from hot gas phase combustion products. Results show a strong functional dependence of emissivity on temperature, attributed to the combined effects of thermal and oxidative processes. Using the measured emissivity, radiance measurements from several burning samples were corrected for the presence of soot and for changes in emissivity, to yield quantitative surface temperature measurements. Ultimately the results will be used to develop a full-field, non-contact temperature measurement that will be used in spacebased combustion investigations.

Environmental factors that influence prescribed burning in the Northern Plains

USGS Publications Warehouse

Kruse, A.D.; Higgins, K.F.; Piehl, J.L.

1983-01-01

Several environmental conditions were recorded and analyzed for 192 prescribed burns in the Northern Great Plains. The purpose of these burns was to improve wildlife habitat and manipulate native prairie vegetation. All of the fires occurred in grassland and shrubsteppe vegetation types. Fuels were predominantly grasses and forbs intermixed with patches of shrubs. Nearly all of the fuels were 0.05 cm/h, do not burn. However, these are good conditions to burn stockpiles of unwanted fuels that are usually high risk elements during regular prescribed burns.2) Produce partial burns. Partial burns are defined as those where fire is discontinuous and patches of standing and lodged vegetation are left unburned. Partial burns occur most often when fine fuels feel moist when handled, where less than 2 days have passed since the last measurable precipitation, and when cloud cover is complete. Other conditions associated with partial burns are relative humidities >50 percent, temperatures 32 km/h, relative humidities 35 deg.C. These conditions occur most often in July, August, and September, but can occur anytime from April through October.

Willingness-to-pay function for two fuel treatments to reduce wildfire acreage burned: A scope test and comparison of white and hispanic households

Treesearch

John B. Loomis; Hung Le Trong; Armando González-Cabán

2009-01-01

We estimate a marginal benefit function for using prescribed burning and mechanical fuel reduction programs to reduce acres burned by wildfire in three states. Since each state had different acre reductions, a statistically significant coefficient on the reduction in acres burned is also a split sample scope test frequently used as an indicator of the internal validity...

Reductions in emissions of carbonaceous particulate matter and polycyclic aromatic hydrocarbons from combustion of biomass pellets in comparison with raw fuel burning.

PubMed

Shen, Guofeng; Tao, Shu; Wei, Siye; Zhang, Yanyan; Wang, Rong; Wang, Bin; Li, Wei; Shen, Huizhong; Huang, Ye; Chen, Yuanchen; Chen, Han; Yang, Yifeng; Wang, Wei; Wei, Wen; Wang, Xilong; Liu, Wenxing; Wang, Xuejun; Masse Simonich, Staci L y

2012-06-05

Biomass pellets are emerging as a cleaner alternative to traditional biomass fuels. The potential benefits of using biomass pellets include improving energy utilization efficiency and reducing emissions of air pollutants. To assess the environmental, climate, and health significance of replacing traditional fuels with biomass pellets, it is critical to measure the emission factors (EFs) of various pollutants from pellet burning. However, only a few field measurements have been conducted on the emissions of carbon monoxide (CO), particulate matter (PM), and polycyclic aromatic hydrocarbons (PAHs) from the combustion of pellets. In this study, pine wood and corn straw pellets were burned in a pellet burner (2.6 kW), and the EFs of CO, organic carbon, elemental carbon, PM, and PAHs (EF(CO), EF(OC), EF(EC), EF(PM), and EF(PAH)) were determined. The average EF(CO), EF(OC), EF(EC), and EF(PM) were 1520 ± 1170, 8.68 ± 11.4, 11.2 ± 8.7, and 188 ± 87 mg/MJ for corn straw pellets and 266 ± 137, 5.74 ± 7.17, 2.02 ± 1.57, and 71.0 ± 54.0 mg/MJ for pine wood pellets, respectively. Total carbonaceous carbon constituted 8 to 14% of the PM mass emitted. The measured values of EF(PAH) for the two pellets were 1.02 ± 0.64 and 0.506 ± 0.360 mg/MJ, respectively. The secondary side air supply in the pellet burner did not change the EFs of most pollutants significantly (p > 0.05). The only exceptions were EF(OC) and EF(PM) for pine wood pellets because of reduced combustion temperatures with the increased air supply. In comparison with EFs for the raw pine wood and corn straw, EF(CO), EF(OC), EF(EC), and EF(PM) for pellets were significantly lower than those for raw fuels (p < 0.05). However, the differences in EF(PAH) were not significant (p > 0.05). Based on the measured EFs and thermal efficiencies, it was estimated that 95, 98, 98, 88, and 71% reductions in the total emissions of CO, OC, EC, PM, and PAHs could be achieved by replacing the raw biomass fuels combusted in

Mass Spectrometry of Polymer Electrolyte Membrane Fuel Cells.

PubMed

Johánek, Viktor; Ostroverkh, Anna; Fiala, Roman; Rednyk, Andrii; Matolín, Vladimír

2016-01-01

The chemical analysis of processes inside fuel cells under operating conditions in either direct or inverted (electrolysis) mode and their correlation with potentiostatic measurements is a crucial part of understanding fuel cell electrochemistry. We present a relatively simple yet powerful experimental setup for online monitoring of the fuel cell exhaust (of either cathode or anode side) downstream by mass spectrometry. The influence of a variety of parameters (composition of the catalyst, fuel type or its concentration, cell temperature, level of humidification, mass flow rate, power load, cell potential, etc.) on the fuel cell operation can be easily investigated separately or in a combined fashion. We demonstrate the application of this technique on a few examples of low-temperature (70°C herein) polymer electrolyte membrane fuel cells (both alcohol- and hydrogen-fed) subjected to a wide range of conditions.

Mass Spectrometry of Polymer Electrolyte Membrane Fuel Cells

PubMed Central

Ostroverkh, Anna; Fiala, Roman; Rednyk, Andrii; Matolín, Vladimír

2016-01-01

The chemical analysis of processes inside fuel cells under operating conditions in either direct or inverted (electrolysis) mode and their correlation with potentiostatic measurements is a crucial part of understanding fuel cell electrochemistry. We present a relatively simple yet powerful experimental setup for online monitoring of the fuel cell exhaust (of either cathode or anode side) downstream by mass spectrometry. The influence of a variety of parameters (composition of the catalyst, fuel type or its concentration, cell temperature, level of humidification, mass flow rate, power load, cell potential, etc.) on the fuel cell operation can be easily investigated separately or in a combined fashion. We demonstrate the application of this technique on a few examples of low-temperature (70°C herein) polymer electrolyte membrane fuel cells (both alcohol- and hydrogen-fed) subjected to a wide range of conditions. PMID:28042492

Frequent Prescribed Burning as a Long-term Practice in Longleaf Pine Forests Does Not Affect Detrital Chemical Composition.

PubMed

Coates, T Adam; Chow, Alex T; Hagan, Donald L; Wang, G Geoff; Bridges, William C; Dozier, James H

2017-09-01

The O horizon, or detrital layer, of forest soils is linked to long-term forest productivity and health. Fuel reduction techniques, such as prescribed fire, can alter the thickness and composition of this essential ecosystem component. Developing an understanding of the changes in the chemical composition of forest detritus due to prescribed fire is essential for forest managers and stakeholders seeking sustainable, resilient, and productive ecosystems. In this study, we evaluated fuel quantity, fuel structure, and detrital chemical composition in longleaf pine ( Miller) forests that have been frequently burned for the last 40 yr at the Tom Yawkey Wildlife Center in Georgetown, SC. Our results suggest that frequent prescribed fire reduces forest fuel quantity ( < 0.01) and vertical structure ( = 0.01). Using pyrolysis-gas chromatography/mass spectrometry as a molecular technique to analyze detrital chemical composition, including aromatic compounds and polycyclic aromatic hydrocarbons, we found that the chemical composition of forest detritus was nearly uniform for both unburned and burned detritus. Our burning activities varied in the short term, consisting of annual dormant, annual growing, and biennial dormant season burns. Seasonal distinctions were present for fuel quantity and vertical fuel structure, but these differences were not noted for the benzene/phenol ratio. These results are significant as more managers consider burning existing longleaf stands while determining effective management practices for longleaf stands yet to be established. Managers of such stands can be confident that frequent, low-intensity, low-severity prescribed burns in longleaf pine forests do little to affect the long-term chemical composition of forest detritus. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Coolant mass flow equalizer for nuclear fuel

DOEpatents

Betten, Paul R.

1978-01-01

The coolant mass flow distribution in a liquid metal cooled reactor is enhanced by restricting flow in sub-channels defined in part by the peripheral fuel elements of a fuel assembly. This flow restriction, which results in more coolant flow in interior sub-channels, is achieved through the use of a corrugated liner positioned between the bundle of fuel elements and the inner wall of the fuel assembly coolant duct. The corrugated liner is expandable to accommodate irradiation induced growth of fuel assembly components.

Hybrid fuel formulation and technology development

NASA Technical Reports Server (NTRS)

Dean, D. L.

1995-01-01

The objective was to develop an improved hybrid fuel with higher regression rate, a regression rate expression exponent close to 0.5, lower cost, and higher density. The approach was to formulate candidate fuels based on promising concepts, perform thermomechanical analyses to select the most promising candidates, develop laboratory processes to fabricate fuel grains as needed, fabricate fuel grains and test in a small lab-scale motor, select the best candidate, and then scale up and validate performance in a 2500 lbf scale, 11-inch diameter motor. The characteristics of a high performance fuel have been verified in 11-inch motor testing. The advanced fuel exhibits a 15% increase in density over an all hydrocarbon formulation accompanied by a 50% increase in regression rate, which when multiplied by the increase in density yields a 70% increase in fuel mass flow rate; has a significantly lower oxidizer-to-fuel (O/F) ratio requirement at 1.5; has a significantly decreased axial regression rate variation making for more uniform propellant flow throughout motor operation; is very clean burning; extinguishes cleanly and quickly; and burns with a high combustion efficiency.

Mass Burns Disaster in Abule-egba, Lagos, Nigeria from a Petroleum Pipeline Explosion Fire

PubMed Central

Fadeyibi, I.O.; Omosebi, D.T.; Jewo, P.I.; Ademiluyi, S.A.

2009-01-01

Summary The aim of this paper is to review the basic principles of triage in mass burns disasters and discuss the experience of the Lagos State University Teaching Hospital (LASUTH), Ikeja, Nigeria, in the December 2006 disaster at Abule-Egba, Lagos, Nigeria. It is hoped that the experience gained will help in the planning for and management of similar disasters in the developing countries with limited facilities. Burn injury has been described as the severest form of trauma and its management is very challenging as it is often accompanied by numerous pathophysiological changes. Successful management requires expert management by well-trained personnel in equipped and dedicated centres. In mass disasters the total number of victims may exceed the capability of the facility and its staff and a system for sorting out the patients and caring for those that will benefit from the facilities available needs to be developed. Other patients will either be sent to other medical facilities for further treatment or discharged after initial care for future follow-up. Documented experiences in the management of mass burns disasters from petroleum pipeline explosions from developing countries are rare. However, petroleum pipeline explosions, especially in the Lagos area of Nigeria, are relatively common. These cases have been associated with a variety of factors. The resulting morbidity and mortality have been high. LASUTH has a dedicated burns centre, which has received and managed many burn patients. Triage is the medical process of screening patients according to their need of treatment and the resources available. The aims and objectives of triage are discussed, its various levels described, and the final goals elaborated. All the burn victims involved in the 2006 disaster were studied, together with the triage carried out at different levels and the consequent sorting of the patients. Standard burns management was carried out. A total of 385 patients sustained burns of

An evaluation of the uncertainties in biomass burning emissions

NASA Astrophysics Data System (ADS)

Yano, A.; Garcia Menendez, F.; Hu, Y.; Odman, M.

2012-12-01

The contribution of biomass burning emissions to the atmospheric loads of gases and aerosols can lead to major air quality problems and have significant climate impacts. Whether from wildfires, natural or human-induced, or controlled burns, biomass burning emissions are an important source of air pollutants regionally in certain parts of the world as well as globally. There are two common ways of estimating biomass burning emissions: by using either ground-based information or satellite observations. When there is sufficient local information about the burn area, the types of fuels and their consumption amounts, and the progression of the fire, ground-based estimation is preferred. For controlled burns a.k.a. prescribed burns and wildfires in places where land management is practiced to a certain extent there is typically sufficient ground-based information for emissions estimation. However, for remote regions where no ground-based information is available on the size, intensity, or the spread of the fire, estimates based on satellite observations are preferred. For example, burn location, size and timing information can be obtained from satellite retrievals of thermal anomalies and fuel loading information can be obtained from satellite products of vegetation cover. In both cases, reasonable emission estimates for a variety of pollutants can be obtained by using emission factors (mass of pollutant released per unit mass of fuel consumed) derived from field or laboratory studies. Here, emissions from a controlled burn and a wildfire are estimated using both ground-based information and satellite observations. The controlled burn was conducted on 17 November 2009 near Santa Barbara, California over 80 ha of land covered with chaparral. An aircraft tracked the smoke plume and measured CO2, light scattering, as well as meteorological parameters during the burn (Akagi et al., 2011). The wildfire is from the summer of 2008 when tens of thousands hectares of wild land

Biogas Laminar Burning Velocity and Flammability Characteristics in Spark Ignited Premix Combustion

NASA Astrophysics Data System (ADS)

Anggono, Willyanto; Wardana, I. N. G.; Lawes, M.; Hughes, K. J.; Wahyudi, Slamet; Hamidi, Nurkholis; Hayakawa, Akihiro

2013-04-01

Spherically expanding flames propagating at constant pressure were employed to determine the laminar burning velocity and flammability characteristics of biogas-air mixtures in premixed combustion to uncover the fundamental flame propagation characteristics of a new alternative and renewable fuel. The results are compared with those from a methane-air flame. Biogas is a sustainable and renewable fuel that is produced in digestion facilities. The composition of biogas discussed in this paper consists of 66.4% methane, 30.6% carbon dioxide and 3% nitrogen. Burning velocity was measured at various equivalence ratios (phi) using a photographic technique in a high pressure fan-stirred bomb, the initial condition being at room temperature and atmospheric pressure. The flame for methane-air mixtures propagates from phi=0.6 till phi=1.3. The flame at phi >= 1.4 does not propagate because the combustion reaction is quenched by the larger mass of fuel. At phi<=0.5, it does not propagate as well since the heat of reaction is insufficient to burn the mixtures. The flame for biogas-air mixtures propagates in a narrower range, that is from phi=0.6 to phi=1.2. Different from the methane flame, the biogas flame does not propagate at phi>=1.3 because the heat absorbed by inhibitors strengthens the quenching effect by the larger mass of fuel. As in the methane flame, the biogas flame at phi<=0.5 does not propagate. This shows that the effect of inhibitors in extremely lean mixtures is small. Compared to a methane-air mixture, the flammability characteristic (flammable region) of biogas becomes narrower in the presence of inhibitors (carbon dioxide and nitrogen) and the presence of inhibitors causes a reduction in the laminar burning velocity. The inhibitor gases work more effectively at rich mixtures because the rich biogas-air mixtures have a higher fraction of carbon dioxide and nitrogen components compared to the lean biogas-air mixtures.

Method of burning sulfur-containing fuels in a fluidized bed boiler

DOEpatents

Jones, Brian C.

1982-01-01

A method of burning a sulfur-containing fuel in a fluidized bed of sulfur oxide sorbent wherein the overall utilization of sulfur oxide sorbent is increased by comminuting the bed drain solids to a smaller average particle size, preferably on the order of 50 microns, and reinjecting the comminuted bed drain solids into the bed. In comminuting the bed drain solids, particles of spent sulfur sorbent contained therein are fractured thereby exposing unreacted sorbent surface. Upon reinjecting the comminuted bed drain solids into the bed, the newly-exposed unreacted sorbent surface is available for sulfur oxide sorption, thereby increasing overall sorbent utilization.

A Survey of Studies on Ignition and Burn of Inertially Confined Fuels

NASA Astrophysics Data System (ADS)

Atzeni, Stefano

2016-10-01

A survey of studies on ignition and burn of inertial fusion fuels is presented. Potentials and issues of different approaches to ignition (central ignition, fast ignition, volume ignition) are addressed by means of simple models and numerical simulations. Both equimolar DT and T-lean mixtures are considered. Crucial issues concerning hot spot formation (implosion symmetry for central ignition; igniting pulse parameters for fast ignition) are briefly discussed. Recent results concerning the scaling of the ignition energy with the implosion velocity and constrained gain curves are also summarized.

Laboratory Studies of Carbon Emission from Biomass Burning for use in Remote Sensing

NASA Technical Reports Server (NTRS)

Wald, Andrew E.; Kaufman, Yoram J.

1998-01-01

Biomass burning is a significant source of many trace gases in the atmosphere. Up to 25% of the total anthropogenic carbon dioxide added to the atmosphere annually is from biomass burning. However, this gaseous emission from fires is not directly detectable from satellite. Infrared radiance from the fires is. In order to see if infrared radiance can be used as a tracer for these emitted gases, we made laboratory measurements to determine the correlation of emitted carbon dioxide, carbon monoxide and total burned biomass with emitted infrared radiance. If the measured correlations among these quantities hold in the field, then satellite-observed infrared radiance can be used to estimate gaseous emission and total burned biomass on a global, daily basis. To this end, several types of biomass fuels were burned under controlled conditions in a large-scale combustion laboratory. Simultaneous measurements of emitted spectral infrared radiance, emitted carbon dioxide, carbon monoxide, and total mass loss were made. In addition measurements of fuel moisture content and fuel elemental abundance were made. We found that for a given fire, the quantity of carbon burned can be estimated from 11 (micro)m radiance measurements only within a factor of five. This variation arises from three sources, 1) errors in our measurements, 2) the subpixel nature of the fires, and 3) inherent differences in combustion of different fuel types. Despite this large range, these measurements can still be used for large-scale satellite estimates of biomass burned. This is because of the very large possible spread of fire sizes that will be subpixel as seen by Moderate Resolution Imaging Spectroradiometer (MODIS). Due to this large spread, even relatively low-precision correlations can still be useful for large-scale estimates of emitted carbon. Furthermore, such estimates using the MODIS 3.9 (micro)m channel should be even more accurate than our estimates based on 11 (micro)m radiance.

Primary emissions and chemical oxidation of volatile organic compounds emitted from laboratory biomass burning sources during the 2016 FIREX FireLab campaign: measurements from a H3O+ chemical ionization mass spectrometer

NASA Astrophysics Data System (ADS)

Coggon, M. M.; Warneke, C.; Koss, A.; Sekimoto, K.; Yuan, B.; Lim, C. Y.; Hagan, D. H.; Kroll, J. H.; Cappa, C. D.; Gilman, J.; Lerner, B. M.; Jimenez, J. L.; Yokelson, R. J.; Roberts, J. M.; De Gouw, J. A.

2017-12-01

Non-methane organic gases (NMOG) emitted by biomass burning constitute a large source of reactive carbon in the atmosphere. Once emitted, these compounds may undergo series of reactions with the OH radical and nitrogen oxides to form secondary organic aerosol (SOA), ozone, or other health-impacting products. The complex emission profile and strong variability of biomass burning NMOG play an important, yet understudied, role in the variability of air quality outcomes such as SOA and ozone. In this study, we summarize measurements of biomass burning volatile organic compounds (VOCs) conducted using a H3O+ chemical ionization mass spectrometer (H3O+-CIMS) during the 2016 FIREX laboratory campaign in Missoula, MT. Specifically, we will present data demonstrating the chemical evolution of biomass burning VOCs artificially aged in a field-deployable photooxidation chamber and an oxidation flow reactor. More than 50 OH-oxidation experiments were conducted with biomass types representing a range of North American fuels. Across many fuel types, VOCs with high SOA and ozone formation potential, such as aromatics and furans, were observed to quickly react with the OH radical while oxidized species were generated. We compare the calculated OH reactivity of the primary emissions to the calculated OH reactivity used in many photochemical models and highlight areas requiring additional research in order to improve model/measurement comparisons.

Experimental study on flowing burning behaviors of a pool fire with dripping of melted thermoplastics.

PubMed

Xie, Qiyuan; Tu, Ran; Wang, Nan; Ma, Xin; Jiang, Xi

2014-02-28

The objective of this work is to quantitatively investigate the dripping-burning and flowing fire of thermoplastics. A new experimental setup is developed with a heating vessel and a T-trough. Hot thermoplastic liquids are generated in the vessel by electric heating. N2 gas is continuously injected into the vessel to avoid a sudden ignition of fuel in it. The detailed flowing burning behaviors of pool fire in the T-trough are analyzed through the measurements of the mass, heat flux and temperatures etc. The experimental results suggest that a continuous dripping of melted thermoplastic liquids in a nearly constant mass rate can be successfully made in the new setup. It also shows that the mass dripping rate of melted PS liquid is smaller than PP and PE since its large viscosity. In addition, the flame spread velocities of hot liquids of PS in the T-trough are also smaller than that of PP and PE because of its large viscosity. The mass burning rate of the PP and PE pool fire in T-trough are smaller than PS. Finally, considering the heating, melting, dripping and flowing burning behaviors of these polymers, it is suggested that the fire hazard of PE and PP are obviously higher than PS for their faster flowing burning. Copyright © 2013 Elsevier B.V. All rights reserved.

Can a growth model be used to describe forest carbon and water balance after fuel reduction burning in temperate forests?

PubMed

Gharun, Mana; Possell, Malcolm; Vervoort, R Willem; Adams, Mark A; Bell, Tina L

2018-02-15

Empirical evidence from Australia shows that fuel reduction burning significantly reduces the incidence and extent of unplanned fires. However, the integration of environmental values into fire management operations is not yet well-defined and requires further research and development. WAVES, a plant growth model that incorporates Soil-Vegetation-Atmosphere Transfer, was used to simulate the hydrological and ecological effects of three fuel management scenarios on a forest ecosystem. WAVES was applied using inputs from a set of forest plots for one year after three potential scenarios: (1) all litter removed, (2) all litter and 50% of the understorey removed, (3) all litter and understorey removed. Modelled outputs were compared with sites modelled with no-fuel reduction treatment (Unburnt). The key change between unburnt and fuel reduced forests was a significant increase in soil moisture after fire. Predictions of the recovery of aboveground carbon as plant biomass were driven by model structure and thus variability in available light and soil moisture at a local scale. Similarly, effects of fuel reduction burning on water processes were mainly due to changes in vegetation interception capacity (i.e. regrowth) and soil evaporation. Predicted effects of fuel reduction burning on total evapotranspiration (ET) - the major component of water balance - were marginal and not significant, even though a considerable proportion of ET had effectively been transferred from understorey to overstorey. In common with many plant growth models, outputs from WAVES are dictated by the assumption that overstorey trees continue to grow irrespective of their age or stage of maturity. Large areas of eucalypt forests and woodlands in SE Australia are well beyond their aggrading phase and are instead over-mature. The ability of these forests to rapidly respond to greater availability of water remains uncertain. Copyright © 2017 Elsevier B.V. All rights reserved.

Organic aerosols and inorganic species from post-harvest agricultural-waste burning emissions over northern India: impact on mass absorption efficiency of elemental carbon.

PubMed

Rajput, Prashant; Sarin, M M; Sharma, Deepti; Singh, Darshan

2014-01-01

Atmospheric PM2.5 (particulate matter with aerodynamic diameter of ≤ 2.5 μm), collected from a source region [Patiala: 30.2 °N; 76.3 °E; 250 m above mean sea level] of emissions from post-harvest agricultural-waste (paddy-residue) burning in the Indo-Gangetic Plain (IGP), North India, has been studied for its chemical composition and impact on regional atmospheric radiative forcing. On average, organic aerosol mass accounts for 63% of PM2.5, whereas the contribution of elemental carbon (EC) is ∼3.5%. Sulphate, nitrate and ammonium contribute up to ∼85% of the total water-soluble inorganic species (WSIS), which constitutes ∼23% of PM2.5. The potassium-to-organic carbon ratio from paddy-residue burning emissions (KBB(+)/OC: 0.05 ± 0.01) is quite similar to that reported from Amazonian and Savanna forest-fires; whereas non-sea-salt-sulphate-to-OC ratio (nss-SO4(2-)/OC: 0.21) and nss-SO4(2-)/EC ratio of 2.6 are significantly higher (by factor of 5 to 8). The mass absorption efficiency of EC (3.8 ± 1.3 m(2) g(-1)) shows significant decrease with a parallel increase in the concentrations of organic aerosols and scattering species (sulphate and nitrate). A cross plot of OC/EC and nss-SO4(2-)/EC ratios show distinct differences for post-harvest burning emissions from paddy-residue as compared to those from fossil-fuel combustion sources in south-east Asia.

Nonlinear Burn Control in Tokamaks using Heating, Non-axisymmetric Magnetic Fields, Isotopic fueling and Impurity injection

NASA Astrophysics Data System (ADS)

Pajares, Andres; Schuster, Eugenio

2016-10-01

Plasma density and temperature regulation in future tokamaks such as ITER is arising as one of the main problems in nuclear-fusion control research. The problem, known as burn control, is to regulate the amount of fusion power produced by the burning plasma while avoiding thermal instabilities. Prior work in the area of burn control considered different actuators, such as modulation of the auxiliary power, modulation of the fueling rate, and controlled impurity injection. More recently, the in-vessel coil system was suggested as a feasible actuator since it has the capability of modifying the plasma confinement by generating non-axisymmetric magnetic fields. In this work, a comprehensive, model-based, nonlinear burn control strategy is proposed to integrate all the previously mentioned actuators. A model to take into account the influence of the in-vessel coils on the plasma confinement is proposed based on the plasma collisionality and the density. A simulation study is carried out to show the capability of the controller to drive the system between different operating points while rejecting perturbations. Supported by the US DOE under DE-SC0010661.

Estimating the Number of Low-Income Americans Exposed to Household Air Pollution from Burning Solid Fuels

PubMed Central

Rogalsky, Derek K.; Mendola, Pauline; Metts, Tricia A.

2014-01-01

Background: Exposure to household air pollution (HAP) from inefficient biomass and coal stoves kills nearly 4 million people every year worldwide. HAP is an environmental risk associated with poverty that affects an estimated 3 billion people mostly in low- and middle-income countries. Objectives: Our goal was to estimate the number of low-income Americans exposed to potentially health-damaging concentrations of HAP. Methods: We mapped county-level data for the percentage of households using wood, coal, and/or coke as their primary heating fuel along with percent of the population below the federal poverty level. Using U.S. Census data and the likelihood of fugitive emissions as reported in the literature, we estimated the number of low-income Americans potentially exposed to HAP. Results: Solid fuel is the primary heating source for > 2.5 million U.S. households, or 6.5 million people. The mapping exercise showed several rural areas, primarily in the northern and western regions, that have high levels of solid-fuel use and poverty. We then identified 117 counties with high co-incident poverty and solid-fuel use as high-priority counties for research into potential health risks from HAP. We estimate that between 500,000 and 600,000 low-income people in the United States are likely exposed to HAP from burning solid fuels within their homes. Conclusion: HAP occurs within the United States and should be further investigated for adverse health risks, especially among those living in areas with rural poverty. Citation: Rogalsky DK, Mendola P, Metts TA, Martin WJ II. 2014. Estimating the number of low-income Americans exposed to household air pollution from burning solid fuels. Environ Health Perspect 122:806–810; http://dx.doi.org/10.1289/ehp.1306709 PMID:24833615

Prescribed burning in the North Central States.

Treesearch

Linda R. Donoghue; Von J. Johnson

1975-01-01

Describes 5 years of prescribed burning in the North Central States from 1968 through 1972. Provides information concerning participating agencies, burned-acreage, purpose-of-burn, fuels, and weather. Also examines other aspects such as ignition and burning techniques, hours-to-complete, time of fire start, and cost-per-acre.

Heterogeneous kinetics of N2O5 reactive uptake and chlorine activation in authentic biomass burning aerosol

NASA Astrophysics Data System (ADS)

Sullivan, R. C.; Jahl, L.; Goldberger, L.; Ahern, A.; Thornton, J. A.

2017-12-01

Nitryl chloride (ClNO2) is a nighttime reservoir of NOx that is formed from the uptake of dinitrogen pentoxide (N2O5) into particles containing chloride. The formation of ClNO2 from heterogeneous reactions of N2O5(g) with authentic biomass burning aerosol has not previously been studied. We observed the rapid production of N2O5 and then ClNO2 during dark chemical transformations of biomass burning aerosol produced from a variety of fuels using both a smog chamber and an aerosol flow tube reactor. Iodide adduct chemical ionization mass spectrometry was used to measure gas phase ClNO2 and N2O5, and acetate chemical ionization mass spectrometry to measure gaseous HCl and other compounds, while a soot particle aerosol mass spectrometer measured changes in aerosol composition as chloride was displaced by nitrate. Upon the addition of ozone to the biomass burning smoke, N2O5 was always rapidly formed and ClNO2 was subsequently detected in the gas phase. During experiments at high relative humidity, we observed decreases in particulate chloride and increases in particulate nitrate which we believe are due to acid displacement of HCl(g) by HNO3 since no additional ClNO2 was produced in the gas phase. The reactive uptake probability of N2O5 on authentic biomass burning aerosol and the yield of ClNO2 were determined for the first time using chamber and flow tube experiments on smoke from biomass fuels including sawgrass, giant cutgrass, palmetto leaves, and ponderosa pine. These experiments confirm the formation of N2O5 and ClNO2 in biomass burning emissions and suggest that biomass burning is a likely source of continental ClNO2 and HCl.

Electrochemical enhancement of nitric oxide removal from simulated lean-burn engine exhaust via solid oxide fuel cells.

PubMed

Huang, Ta-Jen; Wu, Chung-Ying; Lin, Yu-Hsien

2011-07-01

A solid oxide fuel cell (SOFC) unit is constructed with Ni-YSZ as the anode, YSZ as the electrolyte, and La(0.6)Sr(0.4)CoO(3)-Ce(0.9)Gd(0.1)O(1.95) as the cathode. The SOFC operation is performed at 600 °C with a cathode gas simulating the lean-burn engine exhaust and at various fixed voltage, at open-circuit voltage, and with an inert gas flowing over the anode side, respectively. Electrochemical enhancement of NO decomposition occurs when an operating voltage is generated; higher O(2) concentration leads to higher enhancement. Smaller NO concentration results in larger NO conversion. Higher operating voltage and higher O(2) concentration can lead to both higher NO conversion and lower fuel consumption. The molar rate of the consumption of the anode fuel can be very much smaller than that of NO to N(2) conversion. This makes the anode fuel consumed in the SOFC-DeNO(x) process to be much less than the equivalent amount of ammonia consumed in the urea-based selective catalytic reduction process. Additionally, the NO conversion increases with the addition of propylene and SO(2) into the cathode gas. These are beneficial for the application of the SOFC-DeNO(x) technology on treating diesel and other lean-burn engine exhausts.

Preliminary Effects of Prescribed Burning and Thinning as Fuel Reduction Treatments on the Piedmont Soils of the Clemson Experimental Forest

Treesearch

Victor B. Shelburne; M. Forbes Boyle; Darren J. Lione; Thomas A. Waldrop

2004-01-01

This study is a component of the National Fire and Fire Surrogate (NFFS) Study which is an integrated national network of long-term interdisciplinary research to facilitate broad applicability of fuel impacts. This part of the NFFS study in the Piedmont of South Carolina studied three ways of reducing fuel loads (prescribed burning, thinning, and the two in combination...

Status of the nuclear measurement stations for the process control of spent fuel reprocessing at AREVA NC/La Hague

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eleon, Cyrille; Passard, Christian; Hupont, Nicolas

2015-07-01

Nuclear measurements are used at AREVA NC/La Hague for the monitoring of spent fuel reprocessing. The process control is based on gamma-ray spectroscopy, passive neutron counting and active neutron interrogation, and gamma transmission measurements. The main objectives are criticality and safety, online process monitoring, and the determination of the residual fissile mass and activities in the metallic waste remained after fuel shearing and dissolution (empty hulls, grids, end pieces), which are put in radioactive waste drums before compaction. The whole monitoring system is composed of eight measurement stations which will be described in this paper. The main measurement stations no.more » 1, 3 and 7 are needed for criticality control. Before fuel element shearing for dissolution, station no. 1 allows determining the burn-up of the irradiated fuel by gamma-ray spectroscopy with HP Ge (high purity germanium) detectors. The burn-up is correlated to the {sup 137}Cs and {sup 134}Cs gamma emission rates. The fuel maximal mass which can be loaded in one bucket of the dissolver is estimated from the lowest burn-up fraction of the fuel element. Station no. 3 is dedicated to the control of the correct fuel dissolution, which is performed with a {sup 137}Cs gamma ray measurement with a HP Ge detector. Station no. 7 allows estimating the residual fissile mass in the drums filled with the metallic residues, especially in the hulls, from passive neutron counting (spontaneous fission and alpha-n reactions) and active interrogation (fission prompt neutrons induced by a pulsed neutron generator) with proportional {sup 3}He detectors. The measurement stations have been validated for the reprocessing of Uranium Oxide (UOX) fuels with a burn-up rate up to 60 GWd/t. This paper presents a brief overview of the current status of the nuclear measurement stations. (authors)« less

Inert matrix fuel in dispersion type fuel elements

NASA Astrophysics Data System (ADS)

Savchenko, A. M.; Vatulin, A. V.; Morozov, A. V.; Sirotin, V. L.; Dobrikova, I. V.; Kulakov, G. V.; Ershov, S. A.; Kostomarov, V. P.; Stelyuk, Y. I.

2006-06-01

The advantages of using inert matrix fuel (IMF) as a dispersion fuel in an aluminium alloy matrix are considered, in particular, low temperatures in the fuel centre, achievable high burn-ups, serviceability in transients and an environmentally friendly process of fuel rod fabrication. Two main versions of IMF are under development at A.A. Bochvar Institute, i.e. heterogeneous or isolated distribution of plutonium. The out-of-pile results on IMF loaded with uranium dioxide as plutonium simulator are presented. Fuel elements with uranium dioxide composition fabricated at A.A. Bochvar Institute are currently under MIR tests (RIAR, Dimitrovgrad). The fuel elements reached a burn-up of 88 MW d kg-1 (equivalent to the burn up of the standard uranium dioxide pelletized fuel) without loss of leak-tightness of the cladding. The feasibility of fabricating IMF of these particular types with plutonium dioxide is considered with a view to in-pile irradiation.

Mass Loss of Coal Particles Burning in Fluidized Bed

NASA Astrophysics Data System (ADS)

Pełka, Piotr

2017-06-01

In this work many conclusions resulting from research carried out on the coal combustion process of the chosen coal type and its accompanying erosion in a two-phase flow of inert material have been presented. The purpose of this flow was to present a model of the conditions of the central and upper zone of the combustion chamber of the fluidized boiler. In the opinion of many authors (Basu, 1999; Chirone et al., 1991), the erosion process results from the contact of a fuel particle with particles of inert material that is responsible for generating fine fuel particles of less than 100 mm. If the particles are in the upper zone of the boiler where there is oxygen deficit, they can increase the loss of incomplete combustion substantially. The results of research do not confirm this common thesis, but rather indicate that the process of comminution that results from erosion under oxidative conditions contributes to the increase of substantial mass loss of a coal particle, however the increased mass loss of particle during combustion is first and foremost due to the whole process of removal of ash from the reactionary surface of a fuel particle. Nevertheless, in the conditions of oxygen deficit the comminution of particles as a result of the erosion process is negligible

Alternative Fuels Data Center: Mass Transit

Science.gov Websites

traveled and fuel used by private vehicles. Vehicle fleet managers, corporate decision makers, and public effective incentives for fleet managers and corporate decision makers to build mass transit ridership

Theoretical studies of massive stars. II - Evolution of a 15 solar-mass star from carbon shell burning to iron core collapse

NASA Technical Reports Server (NTRS)

Sparks, W. M.; Endal, A. S.

1980-01-01

The evolution of a Population I star of 15 solar masses is described from the carbon shell burning stage to the formation and collapse of an iron core. An unusual aspect of the evolution is that neon ignition occurs off-center and neon burning propagates inward by a series of shell flashes. The extent of the core burning is generally smaller than the Chandrasekhar mass, so that most of the nuclear energy generation occurs in shell sources. Because of degeneracy and the influence of rapid convective mixing, these shell sources are unstable and the core goes through large excursions in temperature and density. The small core also causes the shell sources to converge into a narrow mass region slightly above the Chandrasekhar mass. Thus, the final nucleosynthesis yields are generally small, with silicon being most strongly enhanced with respect to solar system abundances.

Modelling of pore coarsening in the high burn-up structure of UO2 fuel

NASA Astrophysics Data System (ADS)

Veshchunov, M. S.; Tarasov, V. I.

2017-05-01

The model for coalescence of randomly distributed immobile pores owing to their growth and impingement, applied by the authors earlier to consideration of the porosity evolution in the high burn-up structure (HBS) at the UO2 fuel pellet periphery (rim zone), was further developed and validated. Predictions of the original model, taking into consideration only binary impingements of growing immobile pores, qualitatively correctly describe the decrease of the pore number density with the increase of the fractional porosity, however notably underestimate the coalescence rate at high burn-ups attained in the outmost region of the rim zone. In order to overcome this discrepancy, the next approximation of the model taking into consideration triple impingements of growing pores was developed. The advanced model provides a reasonable consent with experimental data, thus demonstrating the validity of the proposed pore coarsening mechanism in the HBS.

Lean burn natural gas fueled S.I. engine and exhaust emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varde, K.S.; Patro, N.; Drouillard, K.

1995-12-31

An experimental study was undertaken to study exhaust emission from a lean-burn natural gas spark ignition engine. The possibility that such an engine may help to reduce exhaust emissions substantially by taking advantage of natural gas fuel properties, such as its antiknock properties and extended lean flammability limit compared to gasoline, was the main motivation behind the investigation. A four cylinder, automotive type spark ignition engine was used in the investigation. The engine was converted to operate on natural gas by replacing its fuel system with a gaseous carburetion system. A 3-way metal metrix catalytic converter was used in themore » engine exhaust system to reduce emission levels. The engine operated satisfactorily at an equivalence ratio as lean as 0.6, at all speeds and loads. As a result NOx emissions were significantly reduced. However, hydrocarbon emissions were high, particularly at very lean conditions and light loads. Most of these hydrocarbons were made up of methane with small concentrations of ethane and propane. Coefficient of variations in hydrocarbons were generally high at very lean operating conditions and light loads, but decreased with increasing equivalence ratio and engine speed. Methane concentrations in the engine exhaust decreased with increasing load and equivalence ratio. At lean air-to-fuel ratios and light loads oxidation of methane in the catalyst was substantially limited and no NOx reduction was achieved. In addition, the proportion of nitric oxide in oxides of nitrogen increased with increasing amount of NOx in the engine exhaust. A major problem encountered in the study was the inability of the fuel system to maintain near constant air-to-fuel ratios at steady operating conditions.« less

High Temperature Reactor (HTR) Deep Burn Core and Fuel Analysis: Design Selection for the Prismatic Block Reactor With Results from FY-2011 Activities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michael A. Pope

2011-10-01

The Deep Burn (DB) Project is a U.S. Department of Energy sponsored feasibility study of Transuranic Management using high burnup fuel in the high temperature helium cooled reactor (HTR). The DB Project consists of seven tasks: project management, core and fuel analysis, spent fuel management, fuel cycle integration, TRU fuel modeling, TRU fuel qualification, and HTR fuel recycle. In the Phase II of the Project, we conducted nuclear analysis of TRU destruction/utilization in the HTR prismatic block design (Task 2.1), deep burn fuel/TRISO microanalysis (Task 2.3), and synergy with fast reactors (Task 4.2). The Task 2.1 covers the core physicsmore » design, thermo-hydraulic CFD analysis, and the thermofluid and safety analysis (low pressure conduction cooling, LPCC) of the HTR prismatic block design. The Task 2.3 covers the analysis of the structural behavior of TRISO fuel containing TRU at very high burnup level, i.e. exceeding 50% of FIMA. The Task 4.2 includes the self-cleaning HTR based on recycle of HTR-generated TRU in the same HTR. Chapter IV contains the design and analysis results of the 600MWth DB-HTR core physics with the cycle length, the average discharged burnup, heavy metal and plutonium consumptions, radial and axial power distributions, temperature reactivity coefficients. Also, it contains the analysis results of the 450MWth DB-HTR core physics and the analysis of the decay heat of a TRU loaded DB-HTR core. The evaluation of the hot spot fuel temperature of the fuel block in the DB-HTR (Deep-Burn High Temperature Reactor) core under full operating power conditions are described in Chapter V. The investigated designs are the 600MWth and 460MWth DB-HTRs. In Chapter VI, the thermo-fluid and safety of the 600MWth DB-HTRs has been analyzed to investigate a thermal-fluid design performance at the steady state and a passive safety performance during an LPCC event. Chapter VII describes the analysis results of the TRISO fuel microanalysis of the 600MWth

Hydrogen Burning in Low Mass Stars Constrains Scalar-Tensor Theories of Gravity.

PubMed

Sakstein, Jeremy

2015-11-13

The most general scalar-tensor theories of gravity predict a weakening of the gravitational force inside astrophysical bodies. There is a minimum mass for hydrogen burning in stars that is set by the interplay of plasma physics and the theory of gravity. We calculate this for alternative theories of gravity and find that it is always significantly larger than the general relativity prediction. The observation of several low mass red dwarf stars therefore rules out a large class of scalar-tensor gravity theories and places strong constraints on the cosmological parameters appearing in the effective field theory of dark energy.

Emission characteristics for polycyclic aromatic hydrocarbons from solid fuels burned in domestic stoves in rural China

PubMed Central

SHEN, Guofeng; TAO, Shu; Chen, Yuanchen; Zhang, Yanyan; Wei, Siye; Xue, Miao; Wang, Bin; WANG, Rong; LV, Yan; LI, Wei; SHEN, Huizhong; HUANG, Ye; CHEN, Han

2014-01-01

Emission characterization of polycyclic aromatic hydrocarbons (PAHs) from residential combustion of crop residues, woody material, coal, and biomass pellets in domestic stoves in rural China are compared in term of emission factors (EFs), influencing factors, composition profiles, isomer ratios and phase distributions. The EFs of PAHs vary by two orders of magnitude among fuel types suggesting that a detailed fuel categorization is useful in the development of an emission inventory and potential in emission abatement of PAHs by replacing dirty fuels with relatively cleaner ones. The influence of fuel moisture in biomass burning is non-linear. Biofuels with very low moisture display relatively high emissions as do fuels with very high moisture. Bituminous coals and brushwood yield relatively large fractions of high molecular PAHs. The emission factor of Benzo(a)pyrene equivalent quantity for raw bituminous coal is as high as 52 mg/kg, which is 1–2 orders of magnitude higher than the other fuels. For source diagnosis, high molecular weight isomers are more informative than low molecular weight ones and multiple ratios could be used together whenever possible. PMID:24245776

Outdoor, indoor, and personal black carbon exposure from cookstoves burning solid fuels

PubMed Central

Downward, George S.; Hu, Wei; Rothman, Nat; Reiss, Boris; Wu, Guoping; Wei, Fusheng; Xu, Jun; Seow, Wei Jie; Brunekreef, Bert; Chapman, Robert S.; Qing, Lan; Vermeulen, Roel

2015-01-01

Background Black carbon (BC) emissions from solid fuel combustion are associated with increased morbidity and mortality and are important drivers of climate change. We studied BC measurements, approximated by particulate matter (PM2.5) absorbance, in rural Yunnan province, China whose residents use a variety of solid fuels for cooking and heating including: bituminous and anthracite coal, and wood. Methods Measurements were taken over 2 consecutive 24 h periods from 163 households in 30 villages. PM2.5 absorbance (PMabs) was measured using an EEL 043 Smoke Stain Reflectometer. Results PMabs measurements were higher in wood burning households (16.3 × 10−5 m−1) than bituminous and anthracite coal households (12 and 5.1 × 10−5 m−1 respectively). Among bituminous coal users, measurements varied by a factor of two depending on the coal source. Portable stoves (which are lit outdoors and brought indoors for use) were associated with reduced PMabs levels, but no other impact of stove design was observed. Outdoor measurements were positively correlated with and approximately half the level of indoor measurements (r= 0.49, p<0.01). Conclusion Measurements of BC (as approximated by PMabs) in this population are modulated by fuel type and source. This provides valuable insight into potential morbidity, mortality and climate change contributions of domestic usage of solid fuels. PMID:26452237

Effects of Gas-Phase Radiation and Detailed Kinetics on the Burning and Extinction of a Solid Fuel

NASA Technical Reports Server (NTRS)

Rhatigan, Jennifer L.

2001-01-01

This is the first attempt to analyze both radiation and detailed kinetics on the burning and extinction of a solid fuel in a stagnation-point diffusion flame. We present a detailed and comparatively accurate computational model of a solid fuel flame along with a quantitative study of the kinetics mechanism, radiation interactions, and the extinction limits of the flame. A detailed kinetics model for the burning of solid trioxane (a trimer of formaldehyde) is coupled with a narrowband radiation model, with carbon dioxide, carbon monoxide, and water vapor as the gas-phase participating media. The solution of the solid trioxane diffusion flame over the flammable regime is presented in some detail, as this is the first solution of a heterogeneous trioxane flame. We identify high-temperature and low-temperature reaction paths for the heterogeneous trioxane flame. We then compare the adiabatic solution to solutions that include Surface radiation only and gas-phase and surface radiation using a black surface model. The analysis includes discussion of detailed flame chemistry over the flammable regime and, in particular, at the low stretch extinction limit. We emphasize the low stretch regime of the radiatively participating flame, since this is the region representative of microgravity flames. When only surface radiation is included, two extinction limits exist (the blow-off limit, and the low stretch radiative limit), and the burning rate and maximum flame temperatures are lower, as expected. With the inclusion of surface and gas-phase radiation, results show that, while flame temperatures are lower, the burning rate of the trioxane diffusion flame may actually increase at low stretch rate due to radiative feedback from the flame to the surface.

Burns and military clothing.

PubMed

McLean, A D

2001-02-01

Burn injury is a ubiquitous threat in the military environment. The risks during combat are well recognised, but the handling of fuel, oil, munitions and other hot or flammable materials during peacetime deployment and training also imposes an inherent risk of accidental burn injury. Over the last hundred years, the burn threat in combat has ranged from nuclear weapons to small shoulder-launched missiles. Materials such as napalm and white phosphorus plainly present a risk of burn, but the threat extends to encompass personnel in vehicles attacked by anti-armour weapons, large missiles, fuel-air explosives and detonations/conflagrations on weapons platforms such as ships. Large numbers of burn casualties were caused at Pearl Harbor, in Hiroshima and Nagasaki, Vietnam, during the Arab/Israeli Wars and in the Falkland Islands conflict. The threat from burns is unlikely to diminish, indeed new developments in weapons seek to exploit the vulnerability of the serviceman and servicewoman to burns. Clothing can be a barrier to some types of burn--both inherently in the properties of the material, but also by trapping air between clothing layers. Conversely, ignition of the clothing may exacerbate a burn. There is hearsay that burnt clothing products within a wound may complicate the clinical management, or that materials that melt (thermoplastic materials) should not be worn if there is a burn threat. This paper explores the incidence of burn injury, the mechanisms of heat transfer to bare skin and skin covered by materials, and the published evidence for the complication of wound management by materials. Even light-weight combat clothing can offer significant protection to skin from short duration flash burns; the most vulnerable areas are the parts of the body not covered--face and hands. Multilayered combat clothing can offer significant protection for short periods from engulfment by flames; lightweight tropical wear with few layers offers little protection. Under

Phenol-selective mass spectrometric analysis of jet fuel.

PubMed

Zhu, Haoxuan; Janusson, Eric; Luo, Jingwei; Piers, James; Islam, Farhana; McGarvey, G Bryce; Oliver, Allen G; Granot, Ori; McIndoe, J Scott

2017-08-21

Bromobenzyl compounds react selectively with phenols via the Williamson ether synthesis. An imidazolium charge-tagged bromobenzyl compound can be used to reveal phenol impurities in jet fuel by analysis via electrospray ionization mass spectrometry. The complex matrix as revealed by Cold EI GC/MS analysis is reduced to a few simple sets of compounds in the charge-tagged ESI mass spectrum, primarily substituted phenols and thiols. Examination of jet fuels treated by different refinery methods reveals the efficacy of these approaches in removing these contaminants.

Advanced Characterization of Semivolatile Organic Compounds Emitted from Biomass Burning

NASA Astrophysics Data System (ADS)

Hatch, L. E.; Liu, Y.; Rivas-Ubach, A.; Shaw, J. B.; Lipton, M. S.; Barsanti, K. C.

2017-12-01

Biomass burning (BB) emits large amounts of non-methane organic gases (NMOGs) and primary (directly emitted) particulate matter (PM). NMOGs also react in plume to form secondary PM (i.e., SOA) and ozone. BB-PM has been difficult to represent accurately in models used for chemistry and climate predictions, including for air quality and fire management purposes. Much recent research supports that many previously unconsidered SOA precursors exist, including oxidation of semivolatile compounds (SVOCs). Although many recent studies have characterized relatively volatile BB-derived NMOGs and relatively non-volatile particle-phase organic species, comparatively few studies have performed detailed characterization of SVOCs emitted from BB. Here we present efforts to expand the volatility and compositional ranges of compounds measured in BB smoke. In this work, samples of SVOCs in gas and particle phases were collected from 18 fires representing a range of fuel types during the 2016 FIREX fire laboratory campaign; samples were analyzed by two-dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC-TOFMS) and Fourier-transform ion cyclotron resonance mass spectrometry (FTICR-MS). Hundreds of compounds were detectable in both gas and particle phases by GCxGC-TOFMS whereas thousands of peaks were present in the FTICR mass spectra. Data from both approaches highlight that chemical fingerprints of smoke are fuel/burn-dependent. These efforts support our continued research in building the understanding and model representation of BB emissions and BB-derived SOA.

Advanced Characterization of Semivolatile Organic Compounds Emitted from Biomass Burning

NASA Astrophysics Data System (ADS)

Hatch, L. E.; Liu, Y.; Rivas-Ubach, A.; Shaw, J. B.; Lipton, M. S.; Barsanti, K. C.

2016-12-01

Biomass burning (BB) emits large amounts of non-methane organic gases (NMOGs) and primary (directly emitted) particulate matter (PM). NMOGs also react in plume to form secondary PM (i.e., SOA) and ozone. BB-PM has been difficult to represent accurately in models used for chemistry and climate predictions, including for air quality and fire management purposes. Much recent research supports that many previously unconsidered SOA precursors exist, including oxidation of semivolatile compounds (SVOCs). Although many recent studies have characterized relatively volatile BB-derived NMOGs and relatively non-volatile particle-phase organic species, comparatively few studies have performed detailed characterization of SVOCs emitted from BB. Here we present efforts to expand the volatility and compositional ranges of compounds measured in BB smoke. In this work, samples of SVOCs in gas and particle phases were collected from 18 fires representing a range of fuel types during the 2016 FIREX fire laboratory campaign; samples were analyzed by two-dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC-TOFMS) and Fourier-transform ion cyclotron resonance mass spectrometry (FTICR-MS). Hundreds of compounds were detectable in both gas and particle phases by GCxGC-TOFMS whereas thousands of peaks were present in the FTICR mass spectra. Data from both approaches highlight that chemical fingerprints of smoke are fuel/burn-dependent. These efforts support our continued research in building the understanding and model representation of BB emissions and BB-derived SOA.

Olive Tree Branches Burning: A major pollution source in the Mediterranean

NASA Astrophysics Data System (ADS)

Kostenidou, Evangelia; Kaltsonoudis, Christos; Tsiflikiotou, Maria; Louvaris, Evangelos; Russell, Lynn; Pandis, Spyros

2013-04-01

Olive tree branches burning is a common agricultural waste management practice after the annual pruning of olive trees from November to February. Almost 1 billion (90%) of the olive trees in our planet are located around the Mediterranean, so the corresponding emissions of olive tree branches burning can be a significant source of fine aerosols during the cold months. Organic aerosol produced during the burning of olive tree branches (otBB-OA) was characterized with both direct source-sampling (using a mobile smog chamber) and ambient measurements during the burning season in the area of Patras, Greece. The aerosol emitted consists of organics, black carbon (BC), potassium, chloride, nitrate and sulfate. In addition to NOx, O3, CO and CO2, Volatile Organic Compounds (VOCs) such as methanol, acetonitrile, benzene and toluene were also produced. The Aerosol Mass Spectrometry (AMS) mass spectrum of otBB-OA is characterized by the m-z's27, 29, 39, 41, 43, 44, 55, 57, 67, 69 and 91 and changes as the emissions react with OH and O3. Fourier Transform Infrared Spectroscopy (FTIR) analysis showed that otBB-OA was composed of 48% alkane groups, 27% organic hydroxyl groups, 11% carboxylic acid groups, 11% primary amine groups and 4% carbonyl groups. The oxygen to carbon (O:C) ratio is 0.29±0.04. The otBB-OA AMS mass spectrum differs from the other published biomass burning spectra. The m-z60, used as levoglucosan tracer, is lower than in most biomass burning sources. This is confirmed by Gas Chromatography Mass Spectroscopy (GC-MS) analysis on filters where the levoglucosan to OC mass ratio was between 0.034 and 0.043, close to the lower limit of the reported values for most fuel types. This may lead to an underestimation of the otBB-OA contribution in Southern Europe if levoglucosan is being used as a wood burning tracer. During the olive tree branches burning season, 20 days of ambient measurements were performed. Applying positive matrix factorization (PMF) to the

Moisture contents of brushland fuels desiccated for burning

Treesearch

Stanley B. Carpenter; Jay R. Bentley; Charles A. Graham

1970-01-01

Plots in a manzanita brushfield at Mount Shasta, California, were prepared for burning by aerially spraying with 2,4-D and 2,4,5-T on November 3, 1966, and with paraquat on June 3, 1967. On plots burned June 23-24, only the leaves and twigs were dead and dry; most of the green stems were not consumed. On plots burned under similar conditions 1 year later, the stems...

Utilization of TRISO Fuel with LWR Spent Fuel in Fusion-Fission Hybrid Reactor System

NASA Astrophysics Data System (ADS)

Acır, Adem; Altunok, Taner

2010-10-01

HTRs use a high performance particulate TRISO fuel with ceramic multi-layer coatings due to the high burn up capability and very neutronic performance. TRISO fuel because of capable of high burn up and very neutronic performance is conducted in a D-T fusion driven hybrid reactor. In this study, TRISO fuels particles are imbedded body-centered cubic (BCC) in a graphite matrix with a volume fraction of 68%. The neutronic effect of TRISO coated LWR spent fuel in the fuel rod used hybrid reactor on the fuel performance has been investigated for Flibe, Flinabe and Li20Sn80 coolants. The reactor operation time with the different first neutron wall loads is 24 months. Neutron transport calculations are evaluated by using XSDRNPM/SCALE 5 codes with 238 group cross section library. The effect of TRISO coated LWR spent fuel in the fuel rod used hybrid reactor on tritium breeding (TBR), energy multiplication (M), fissile fuel breeding, average burn up values are comparatively investigated. It is shown that the high burn up can be achieved with TRISO fuel in the hybrid reactor.

Cost Analysis of 48 Burn Patients in a Mass Casualty Explosion Treated at Chang Gung Memorial Hospital.

PubMed

Mathews, Alexandra L; Cheng, Ming-Huei; Muller, John-Michael; Lin, Miffy Chia-Yu; Chang, Kate W C; Chung, Kevin C

2017-01-01

Little is known about the costs of treating burn patients after a mass casualty event. A devastating Color Dust explosion that injured 499 patients occurred on June 27, 2015 in Taiwan. This study was performed to investigate the economic effects of treating burn patients at a single medical center after an explosion disaster. A detailed retrospective analysis on 48 patient expense records at Chang Gung Memorial Hospital after the Color Dust explosion was performed. Data were collected during the acute treatment period between June 27, 2015 and September 30, 2015. The distribution of cost drivers for the entire patient cohort (n=48), patients with a percent total body surface area burn (%TBSA)≥50 (n=20), and those with %TBSA <50 (n=28) were analyzed. The total cost of 48 burn patients over the acute 3-month time period was $2,440,688, with a mean cost per patient of $50,848 ±36,438. Inpatient ward fees (30%), therapeutic treatment fees (22%), and medication fees (11%) were found to be the three highest cost drivers. The 20 patients with a %TBSA ≥50 consumed $1,559,300 (63.8%) of the total expenses, at an average cost of $77,965±34,226 per patient. The 28 patients with a %TBSA <50 consumed $881,387 (36.1%) of care expenses, at an average cost of $31,478±23,518 per patient. In response to this mass casualty event, inpatient ward fees represented the largest expense. Hospitals can reduce this fee by ensuring wound dressing and skin substitute materials are regionally stocked and accessible. Medication fees may be higher than expected when treating a mass burn cohort. In preparation for a future event, hospitals should anticipate patients with a %TBSA≥50 will contribute the majority of inpatient expenses. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cost Analysis of 48 Burn Patients in a Mass Casualty Explosion Treated at Chang Gung Memorial Hospital

PubMed Central

Mathews, Alexandra L.; Cheng, Ming-Huei; Muller, John-Michael; Lin, Miffy Chia-Yu; Chang, Kate W.C.; Chung, Kevin C.

2016-01-01

Introduction Little is known about the costs of treating burn patients after a mass casualty event. A devastating Color Dust explosion that injured 499 patients occurred on June 27, 2015 in Taiwan. This study was performed to investigate the economic effects of treating burn patients at a single medical center after an explosion disaster. Methods A detailed retrospective analysis on 48 patient expense records at Chang Gung Memorial Hospital after the Color Dust explosion was performed. Data were collected during the acute treatment period between June 27, 2015 and September 30, 2015. The distribution of cost drivers for the entire patient cohort (n=48), patients with a percent total body surface area burn (%TBSA) ≥ 50 (n=20), and those with %TBSA <50 (n=28) were analyzed. Results The total cost of 48 burn patients over the acute 3-month time period was $2,440,688, with a mean cost per patient of $50,848 ±36,438. Inpatient ward fees (30%), therapeutic treatment fees (22%), and medication fees (11%) were found to be the three highest cost drivers. The 20 patients with a %TBSA ≥50 consumed $1,559,300 (63.8%) of the total expenses, at an average cost of $77,965 ± 34,226 per patient. The 28 patients with a %TBSA <50 consumed $881,387 (36.1%) of care expenses, at an average cost of $31,478 ± 23,518 per patient. Conclusions In response to this mass casualty event, inpatient ward fees represented the largest expense. Hospitals can reduce this fee by ensuring wound dressing and skin substitute materials are regionally stocked and accessible. Medication fees may be higher than expected when treating a mass burn cohort. In preparation for a future event, hospitals should anticipate patients with a %TBSA ≥ 50 will contribute the majority of inpatient expenses. PMID:27553390

Laboratory measurements of trace gas emissions from biomass burning of fuel types from the southeastern and southwestern United States

NASA Astrophysics Data System (ADS)

Burling, I. R.; Yokelson, R. J.; Griffith, D. W. T.; Johnson, T. J.; Veres, P.; Roberts, J. M.; Warneke, C.; Urbanski, S. P.; Reardon, J.; Weise, D. R.; Hao, W. M.; de Gouw, J.

2010-11-01

Vegetation commonly managed by prescribed burning was collected from five southeastern and southwestern US military bases and burned under controlled conditions at the US Forest Service Fire Sciences Laboratory in Missoula, Montana. The smoke emissions were measured with a large suite of state-of-the-art instrumentation including an open-path Fourier transform infrared (OP-FTIR) spectrometer for measurement of gas-phase species. The OP-FTIR detected and quantified 19 gas-phase species in these fires: CO2, CO, CH4, C2H2, C2H4, C3H6, HCHO, HCOOH, CH3OH, CH3COOH, furan, H2O, NO, NO2, HONO, NH3, HCN, HCl, and SO2. Emission factors for these species are presented for each vegetation type burned. Gas-phase nitrous acid (HONO), an important OH precursor, was detected in the smoke from all fires. The HONO emission factors ranged from 0.15 to 0.60 g kg-1 and were higher for the southeastern fuels. The fire-integrated molar emission ratios of HONO (relative to NOx) ranged from approximately 0.03 to 0.20, with higher values also observed for the southeastern fuels. The majority of non-methane organic compound (NMOC) emissions detected by OP-FTIR were oxygenated volatile organic compounds (OVOCs) with the total identified OVOC emissions constituting 61 ± 12% of the total measured NMOC on a molar basis. These OVOC may undergo photolysis or further oxidation contributing to ozone formation. Elevated amounts of gas-phase HCl and SO2 were also detected during flaming combustion, with the amounts varying greatly depending on location and vegetation type. The fuels with the highest HCl emission factors were all located in the coastal regions, although HCl was also observed from fuels farther inland. Emission factors for HCl were generally higher for the southwestern fuels, particularly those found in the chaparral biome in the coastal regions of California.

Laboratory measurements of trace gas emissions from biomass burning of fuel types from the Southeastern and Southwestern United States

NASA Astrophysics Data System (ADS)

Burling, I. R.; Yokelson, R. J.; Griffith, D. W. T.; Johnson, T. J.; Veres, P.; Roberts, J. M.; Warneke, C.; Urbanski, S. P.; Reardon, J.; Weise, D. R.; Hao, W. M.; de Gouw, J.

2010-07-01

Vegetation commonly managed by prescribed burning was collected from five southeastern and southwestern US military bases and burned under controlled conditions at the US Forest Service Fire Sciences Laboratory in Missoula, Montana. The smoke emissions were measured with a large suite of state-of-the-art instrumentation including an open-path Fourier transform infrared (OP-FTIR) spectrometer for measurement of gas-phase species. The OP-FTIR detected and quantified 19 gas-phase species in these fires: CO2, CO, CH4, C2H2, C2H4, C3H6, HCHO, HCOOH, CH3OH, CH3COOH, furan, H2O, NO, NO2, HONO, NH3, HCN, HCl, and SO2. Emission factors for these species are presented for each vegetation type burned. Gas-phase nitrous acid (HONO), an important OH precursor, was detected in the smoke from all fires. The HONO emission factors ranged from 0.15 to 0.60 g kg-1 and were higher for the southeastern fuels. The fire-integrated molar emission ratios of HONO (relative to NOx) ranged from approximately 0.03 to 0.20, with higher values also observed for the southeastern fuels. The majority of non-methane organic compound (NMOC) emissions detected by OP-FTIR were oxygenated volatile organic compounds (OVOCs) with the total identified OVOC emissions constituting 61±12% of the total measured NMOC on a molar basis. These OVOC may undergo photolysis or further oxidation contributing to ozone formation. Elevated amounts of gas-phase HCl and SO2 were also detected during flaming combustion, with the amounts varying greatly depending on location and vegetation type. The fuels with the highest HCl emission factors were all located in the coastal regions, although HCl was also observed from fuels farther inland. Emission factors for HCl were generally higher for the southwestern fuels, particularly those found in the chaparral biome in the coastal regions of California.

Contributions of ignitions, fuels, and weather to the spatial patterns of burn probability of a boreal landscape

Treesearch

Marc-Andre Parisien; Sean A. Parks; Carol Miller; Meg A. Krawchuck; Mark Heathcott; Max A. Moritz

2011-01-01

The spatial pattern of fire observed across boreal landscapes is the outcome of complex interactions among components of the fire environment. We investigated how the naturally occurring patterns of ignitions, fuels, and weather generate spatial pattern of burn probability (BP) in a large and highly fireprone boreal landscape of western Canada, Wood Buffalo National...

Mass impacts on fuel economies of conventional vs. hybrid electric vehicles.

DOE Office of Scientific and Technical Information (OSTI.GOV)

An, F.; Santini, D. J.; Energy Systems

2004-01-01

The strong correlation between vehicle weight and fuel economy for conventional vehicles (CVs) is considered common knowledge, and the relationship of mass reduction to fuel consumption reduction for conventional vehicles (CVs) is often cited without separating effects of powertrain vs. vehicle body (glider), nor on the ground of equivalent vehicle performance level. This paper challenges the assumption that this relationship is easily summarized. Further, for hybrid electric vehicles (HEVs) the relationship between mass, performance and fuel consumption is not the same as for CVs, and vary with hybrid types. For fully functioning (all wheel regeneration) hybrid vehicles, where battery packmore » and motor(s) have enough power and energy storage, a very large fraction of kinetic energy is recovered and engine idling is effectively eliminated. This paper assesses two important impacts of shifting from conventional to hybrid vehicles in terms of the mass vs. fuel economy relationship - (1) significant improvements in fuel economy with little or no change in mass, and (2) once a switch to hybrid powertrains has been made, the effectiveness of mass reduction in improving fuel economy will be diminished relative to conventional vehicles. In this paper, we discuss vehicle tractive load breakdowns and impacts of hybridization on vehicle efficiency, discuss capture of kinetic energy by conversion to electrical energy via regenerative braking, assess benefits of shutting off the engine when the vehicle does not require power, and investigate energy losses associated with vehicle mass.« less

40 CFR 279.61 - Restrictions on burning.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 28 2013-07-01 2013-07-01 false Restrictions on burning. 279.61... (CONTINUED) STANDARDS FOR THE MANAGEMENT OF USED OIL Standards for Used Oil Burners Who Burn Off-Specification Used Oil for Energy Recovery § 279.61 Restrictions on burning. (a) Off-specification used oil fuel...

40 CFR 279.61 - Restrictions on burning.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 28 2012-07-01 2012-07-01 false Restrictions on burning. 279.61... (CONTINUED) STANDARDS FOR THE MANAGEMENT OF USED OIL Standards for Used Oil Burners Who Burn Off-Specification Used Oil for Energy Recovery § 279.61 Restrictions on burning. (a) Off-specification used oil fuel...

40 CFR 279.61 - Restrictions on burning.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 27 2011-07-01 2011-07-01 false Restrictions on burning. 279.61... (CONTINUED) STANDARDS FOR THE MANAGEMENT OF USED OIL Standards for Used Oil Burners Who Burn Off-Specification Used Oil for Energy Recovery § 279.61 Restrictions on burning. (a) Off-specification used oil fuel...

40 CFR 279.61 - Restrictions on burning.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 27 2014-07-01 2014-07-01 false Restrictions on burning. 279.61... (CONTINUED) STANDARDS FOR THE MANAGEMENT OF USED OIL Standards for Used Oil Burners Who Burn Off-Specification Used Oil for Energy Recovery § 279.61 Restrictions on burning. (a) Off-specification used oil fuel...

An extended version of the SERPENT-2 code to investigate fuel burn-up and core material evolution of the Molten Salt Fast Reactor

NASA Astrophysics Data System (ADS)

Aufiero, M.; Cammi, A.; Fiorina, C.; Leppänen, J.; Luzzi, L.; Ricotti, M. E.

2013-10-01

In this work, the Monte Carlo burn-up code SERPENT-2 has been extended and employed to study the material isotopic evolution of the Molten Salt Fast Reactor (MSFR). This promising GEN-IV nuclear reactor concept features peculiar characteristics such as the on-line fuel reprocessing, which prevents the use of commonly available burn-up codes. Besides, the presence of circulating nuclear fuel and radioactive streams from the core to the reprocessing plant requires a precise knowledge of the fuel isotopic composition during the plant operation. The developed extension of SERPENT-2 directly takes into account the effects of on-line fuel reprocessing on burn-up calculations and features a reactivity control algorithm. It is here assessed against a dedicated version of the deterministic ERANOS-based EQL3D procedure (PSI-Switzerland) and adopted to analyze the MSFR fuel salt isotopic evolution. Particular attention is devoted to study the effects of reprocessing time constants and efficiencies on the conversion ratio and the molar concentration of elements relevant for solubility issues (e.g., trivalent actinides and lanthanides). Quantities of interest for fuel handling and safety issues are investigated, including decay heat and activities of hazardous isotopes (neutron and high energy gamma emitters) in the core and in the reprocessing stream. The radiotoxicity generation is also analyzed for the MSFR nominal conditions. The production of helium and the depletion in tungsten content due to nuclear reactions are calculated for the nickel-based alloy selected as reactor structural material of the MSFR. These preliminary evaluations can be helpful in studying the radiation damage of both the primary salt container and the axial reflectors.

Heat and mass transfer analysis for paraffin/nitrous oxide burning rate in hybrid propulsion

NASA Astrophysics Data System (ADS)

Ben-Basat (Sisi), Shani; Gany, Alon

2016-03-01

This research presents a physical-mathematical model for the combustion of liquefying fuels in hybrid combustors, accounting for blowing effect on the heat transfer. A particular attention is given to a paraffin/nitrous oxide hybrid system. The use of a paraffin fuel in hybrid propulsion has been considered because of its much higher regression rate enabling significantly higher thrust compared to that of common polymeric fuels. The model predicts the overall regression rate (melting rate) of the fuel and the different mechanisms involved, including evaporation, entrainment of droplets of molten material, and mass loss due to melt flow on the condensed fuel surface. Prediction of the thickness and velocity of the liquid (melt) layer formed at the surface during combustion was done as well. Applying the model for an oxidizer mass flux of 45 kg/(s m2) as an example representing experimental range, it was found that 21% of the molten liquid undergoes evaporation, 30% enters the gas flow by the entrainment mechanism, and 49% reaches the end of the combustion chamber as a flowing liquid layer. When increasing the oxidizer mass flux in the port, the effect of entrainment increases while that of the flowing liquid layer along the surface shows a relatively lower contribution. Yet, the latter is predicted to have a significant contribution to the overall mass loss. In practical applications it may cause reduced combustion efficiency and should be taken into account in the motor design, e.g., by reinforcing the paraffin fuel with different additives. The model predictions have been compared to experimental results revealing good agreement.

Emissions of PCDD and PCDF from combustion of forest fuels and sugarcane: a comparison between field measurements and simulations in a laboratory burn facility.

PubMed

Black, R R; Meyer, C P; Touati, A; Gullett, B K; Fiedler, H; Mueller, J F

2011-05-01

Release of PCDD and PCDF from biomass combustion such as forest and agricultural crop fires has been nominated as an important source for these chemicals despite minimal characterisation. Available emission factors that have been experimentally determined in laboratory and field experiments vary by several orders of magnitude from <0.5 μg TEQ (t fuel consumed)(-1) to >100 μg TEQ (t fuel consumed)(-1). The aim of this study was to evaluate the effect of experimental methods on the emission factor. A portable field sampler was used to measure PCDD/PCDF emissions from forest fires and the same fuel when burnt over a brick hearth to eliminate potential soil effects. A laboratory burn facility was used to sample emissions from the same fuels. There was very good agreement in emission factors to air (EF(Air)) for forest fuel (Duke Forest, NC) of 0.52 (range: 0.40-0.79), 0.59 (range: 0.18-1.2) and 0.75 (range: 0.27-1.2) μg TEQ(WHO2005) (t fuel consumed)(-1) for the in-field, over a brick hearth, and burn facility experiments, respectively. Similarly, experiments with sugarcane showed very good agreement with EF(Air) of 1.1 (range: 0.40-2.2), 1.5 (range: 0.84-2.2) and 1.7 (range: 0.34-4.4) μg TEQ (t fuel consumed)(-1) for in-field, over a brick hearth, open field and burn facility experiments respectively. Field sampling and laboratory simulations were in good agreement, and no significant changes in emissions of PCDD/PCDF could be attributed to fuel storage and transport to laboratory test facilities. Copyright © 2011 Elsevier Ltd. All rights reserved.

The influence of prescribed fire and burn interval on fuel loads in four North Carolina forest ecosystems

Treesearch

M.J. Gavazzi; S.G. McNulty

2014-01-01

Prescribed fire is an important management tool in southern US forests, with more acres burned in the South than any other region of the US. Research from prescribed fire studies shows high temporal and spatial variability in available fuel loads due to physiographic, edaphic, meteorological and biological factors. In an effort to account for parts of this variation...

Burning--Gravitational, Chemical, and Nuclear.

ERIC Educational Resources Information Center

Jones, Goronwy Tudor

1991-01-01

Energy problems that incorporate power generation in hydroelectric, fossil-fuel burning, and nuclear power stations are presented. The burning process and the energy released are discussed. Practice problems and solutions, a summary of various energy units and conversion factors, and lists of thought-provoking energies and powers are included. (KR)

Dredge-up and Envelope Burning in Intermediate-Mass Giants of Very Low Metallicity

NASA Astrophysics Data System (ADS)

Herwig, Falk

2004-04-01

The evolution of intermediate-mass stars at very low metallicity during their final thermal pulse asymptotic giant branch (AGB) phase is studied in detail. As representative examples, models with initial masses of 4 and 5Msolar and with a metallicity of Z=0.0001 ([Fe/H]~-2.3) are discussed. The one-dimensional stellar structure and evolution model includes time- and depth-dependent overshooting motivated by hydrodynamic simulations, as well as a full nuclear network and time-dependent mixing. Particular attention is given to high time and space resolution to avoid numerical artifacts related to third dredge-up and hot bottom burning predictions. The model calculations predict very efficient third dredge-up that mixes the envelope with the entire intershell layer or a large fraction thereof and in some cases penetrates into the C/O core below the He shell. In all cases primary oxygen is mixed into the envelope. The models predict efficient envelope burning during the interpulse phase. Depending on the envelope-burning temperature, oxygen is destroyed to varying degrees. The combined effect of dredge-up and envelope burning does not lead to any significant oxygen depletion in any of the cases considered in this study. The large dredge-up efficiency in our model is closely related to the particular properties of the H shell during the dredge-up phase in low-metallicity very metal-poor stars, which is followed here over many thermal pulses. During the dredge-up phase, the temperature just below the convective boundary is large enough for protons to burn vigorously when they are brought into the C-rich environment below the convection boundary by the time- and depth-dependent overshooting. H-burning luminosities of 105 to ~2×106Lsolar are generated. C, and to lesser degree O, is transformed into N in this dredge-up overshooting layer and enters the envelope. The global effect on the CNO abundance is similar to that of hot bottom burning. If the overshoot efficiency is

46 CFR 109.573 - Riveting, welding, and burning operations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Riveting, welding, and burning operations. 109.573... DRILLING UNITS OPERATIONS Miscellaneous § 109.573 Riveting, welding, and burning operations. Except as..., welding, or burning— (1) In a fuel tank; (2) On the boundary of a fuel tank; (3) On pipelines, heating...

A study of burning processes of fossil fuels in straitened conditions of furnaces in low capacity boilers by an example of natural gas

NASA Astrophysics Data System (ADS)

Roslyakov, P. V.; Proskurin, Y. V.; Khokhlov, D. A.; Zaichenko, M. N.

2018-03-01

The aim of this work is to research operations of modern combined low-emission swirl burner with a capacity of 2.2 MW for fire-tube boiler type KV-GM-2.0, to ensure the effective burning of natural gas, crude oil and diesel fuel. For this purpose, a computer model of the burner and furnace chamber has been developed. The paper presents the results of numerical investigations of the burner operation, using the example of natural gas in a working load range from 40 to 100%. The basic features of processes of fuel burning in the cramped conditions of the flame tube have been identified to fundamentally differ from similar processes in the furnaces of steam boilers. The influence of the design of burners and their operating modes on incomplete combustion of fuel and the formation of nitrogen oxides has been determined.

Campaign datasets for Biomass Burning Observation Project (BBOP)

DOE Data Explorer

Kleinman,Larry; Mei,Fan; Arnott,William; Buseck,Peter; Chand,Duli; Comstock,Jennifer; Dubey,Manvendra; Lawson,Paul; Long,Chuck; Onasch,Timothy; Sedlacek,Arthur; Senum,Gunnar; Shilling,John; Springston,Stephen; Tomlinson,Jason; Wang,Jian

2014-04-24

This field campaign will address multiple uncertainties in aerosol intensive properties, which are poorly represented in climate models, by means of aircraft measurements in biomass burning plumes. Key topics to be investigated are: 1. Aerosol mixing state and morphology 2. Mass absorption coefficients (MACs) 3. Chemical composition of non-refractory material associated with light-absorbing carbon (LAC) 4. Production rate of secondary organic aerosol (SOA) 5. Microphysical processes relevant to determining aerosol size distributions and single scattering albedo (SSA) 6. CCN activity. These topics will be investigated through measurements near active fires (0-5 hours downwind), where limited observations indicate rapid changes in aerosol properties, and in biomass burning plumes aged >5 hours. Aerosol properties and their time evolution will be determined as a function of fire type, defined according to fuel and the mix of flaming and smoldering combustion at the source.

Molecular Characterization of Brown Carbon in Biomass Burning Aerosol Particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Peng; Aiona, Paige K.; Li, Ying

Emissions from biomass burning are a significant source of brown carbon (BrC) in the atmosphere. In this study, we investigate the molecular composition of freshly-emitted biomass burning organic aerosol (BBOA) samples collected during test burns of selected biomass fuels: sawgrass, peat, ponderosa pine, and black spruce. We characterize individual BrC chromophores present in these samples using high performance liquid chromatography coupled to a photodiode array detector and a high-resolution mass spectrometer. We demonstrate that both the overall BrC absorption and the chemical composition of light-absorbing compounds depend significantly on the type of biomass fuels and burning conditions. Common BrC chromophoresmore » in the selected BBOA samples include nitro-aromatics, polycyclic aromatic hydrocarbon derivatives, and polyphenols spanning a wide range of molecular weights, structures, and light absorption properties. A number of biofuel-specific BrC chromophores are observed, indicating that some of them may be used as potential markers of BrC originating from different biomass burning sources. On average, ~50% of the light absorption above 300 nm can be attributed to a limited number of strong BrC chromophores, which may serve as representative light-absorbing species for studying atmospheric processing of BrC aerosol. The absorption coefficients of BBOA are affected by solar photolysis. Specifically, under typical atmospheric conditions, the 300 nm absorbance decays with a half-life of 16 hours. A “molecular corridors” analysis of the BBOA volatility distribution suggests that many BrC compounds in the fresh BBOA have low volatility (<1 g m-1) and will be retained in the particle phase under atmospherically relevant conditions.« less

Replacing Burning of Fossil Fuels with Solar Cell and Wind Energy: How Important and How Soon?

NASA Astrophysics Data System (ADS)

Partain, L., II; Hansen, R. T.; Hansen, S. F.; Bennett, D.; Newlands, A.

2016-12-01

The IPCC indicated that atmospheric CO2 rise should stop to control global climate change. CO2 is the longest lived, most problematic anthropogenic greenhouse emission from burning fossil fuel. For 2000 years atmospheric CO2 concentration remained 280 ppm until 1870, when it rose sharply and nonlinearly to 400 ppm, correlated with a 1oC global mean temperature rise. Antarctic ice core data for the past 400,000 years indicate, 80 ppm shifts in atmospheric CO2 concentrations with 10,000-30,000 year interglacial periods at 280 ppm, were between ice-age glacial periods of 75,000-100,000 years at 200 ppm. The last 12,000-year interglacial "Goldilocks" period so far spans 4 civilizations: 6000 years of Western, 4000-5000 years of Inca and Aztec and 7000-8000 years of Chinese civilizations. The UN-led 2015 Paris Agreement set a goal limiting temperature rise to 2oC to prevent devastating climate change. Unfortunately IPCC modeling found a substantial probability of a rise by 4oC or more should all current fossil fuels be burned by 2100. This would result in weather extremes, rising oceans, storm surges and temperatures where low-lying coastal regions, Pacific Islands and large equatorial regions of the world could become uninhabitable. By Swanson's Law, an empirical learning curve observation, solar cell production costs drop 50% for every 10X increase in their cumulative production. After 40 years and over 5 orders-of-magnitude cumulative production increase, solar cells currently provide over 1% of the world's electricity generating capacity at a cost competitive with electricity generated from burning fossil fuels. If their cumulative generating capacity keeps doubling every 2 years (similar to Moore's Law), energy equivalent to all the world's electricity generating capacity could be provided by solar cells by 2028. The variability of solar cell energy can be mitigated by combining it with wind power, storage, super grids, space mirrors, and demand response.

Effect of water injection on nitric oxide emissions of a gas turbine combustor burning natural gas fuel

NASA Technical Reports Server (NTRS)

Marchionna, N. R.; Diehl, L. A.; Trout, A. M.

1973-01-01

The effect of direct water injection on the exhaust gas emissions of a turbojet combustor burning natural gas fuel was investigated. The results are compared with the results from similar tests using ASTM Jet-A fuel. Increasing water injection decreased the emissions of oxides of nitrogen (NOX) and increased the emissions of carbon monoxide and unburned hydrocarbons. The greatest percentage decrease in NOX with increasing water injection was at the lowest inlet-air temperature tested. The effect of increasing inlet-air temperature was to decrease the effect of the water injection. The reduction in NOX due to water injection was almost identical to the results obtained with Jet-A fuel. However, the emission indices of unburned hydrocarbons, carbon monoxide, and percentage nitric oxide in NOX were not.

Emissions from prescribed burning of agricultural fields in the Pacific Northwest

NASA Astrophysics Data System (ADS)

Holder, A. L.; Gullett, B. K.; Urbanski, S. P.; Elleman, R.; O'Neill, S.; Tabor, D.; Mitchell, W.; Baker, K. R.

2017-10-01

Prescribed burns of winter wheat stubble and Kentucky bluegrass fields in northern Idaho and eastern Washington states (U.S.A.) were sampled using ground-, aerostat-, airplane-, and laboratory-based measurement platforms to determine emission factors, compare methods, and provide a current and comprehensive set of emissions data for air quality models, climate models, and emission inventories. Batch measurements of PM2.5, volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated dibenzodioxins/dibenzofurans (PCDDs/PCDFs), and continuous measurements of black carbon (BC), particle mass by size, CO, CO2, CH4, and aerosol characteristics were taken at ground level, on an aerostat-lofted instrument package, and from an airplane. Biomass samples gathered from the field were burned in a laboratory combustion facility for comparison with these ground and aerial field measurements. Emission factors for PM2.5, organic carbon (OC), CH4, and CO measured in the field study platforms were typically higher than those measured in the laboratory combustion facility. Field data for Kentucky bluegrass suggest that biomass residue loading is directly proportional to the PM2.5 emission factor; no such relationship was found with the limited wheat data. CO2 and BC emissions were higher in laboratory burn tests than in the field, reflecting greater carbon oxidation and flaming combustion conditions. These distinctions between field and laboratory results can be explained by measurements of the modified combustion efficiency (MCE). Higher MCEs were recorded in the laboratory burns than from the airplane platform. These MCE/emission factor trends are supported by 1-2 min grab samples from the ground and aerostat platforms. Emission factors measured here are similar to other studies measuring comparable fuels, pollutants, and combustion conditions. The size distribution of refractory BC (rBC) was single modal with a log-normal shape, which was

Mechanistic approach for nitride fuel evolution and fission product release under irradiation

NASA Astrophysics Data System (ADS)

Dolgodvorov, A. P.; Ozrin, V. D.

2017-01-01

A model for describing uranium-plutonium mixed nitride fuel pellet burning was developed. Except fission products generating, the model includes impurities of oxygen and carbon. Nitrogen behaviour in nitride fuel was analysed and the nitrogen chemical potential in solid solution with uranium-plutonium nitride was constructed. The chemical program module was tested with the help of thermodynamic equilibrium phase distribution calculation. Results were compared with analogous data in literature, quite good agreement was achieved, especially for uranium sesquinitride, metallic species and some oxides. Calculation of a process of nitride fuel burning was also conducted. Used mechanistic approaches for fission product evolution give the opportunity to find fission gas release fractions and also volumes of intergranular secondary phases. Calculations present that the most massive secondary phases are the oxide and metallic phases. Oxide phase contain approximately 1 % wt of substance over all time of burning with slightly increasing of content. Metallic phase has considerable rising of mass and by the last stage of burning it contains about 0.6 % wt of substance. Intermetallic phase has less increasing rate than metallic phase and include from 0.1 to 0.2 % wt over all time of burning. The highest element fractions of released gaseous fission products correspond to caesium and iodide.

A combustion model of vegetation burning in "Tiger" fire propagation tool

NASA Astrophysics Data System (ADS)

Giannino, F.; Ascoli, D.; Sirignano, M.; Mazzoleni, S.; Russo, L.; Rego, F.

2017-11-01

In this paper, we propose a semi-physical model for the burning of vegetation in a wildland fire. The main physical-chemical processes involved in fire spreading are modelled through a set of ordinary differential equations, which describe the combustion process as linearly related to the consumption of fuel. The water evaporation process from leaves and wood is also considered. Mass and energy balance equations are written for fuel (leaves and wood) assuming that combustion process is homogeneous in space. The model is developed with the final aim of simulating large-scale wildland fires which spread on heterogeneous landscape while keeping the computation cost very low.

Analysis of derived optical parameters of atmospheric particles during a biomass burning event. Comparison with fossil fuel burning

NASA Astrophysics Data System (ADS)

Costa, A.; Mogo, S.; Cachorro, V.; de Frutos, A.; Medeiros, M.; Martins, R.; López, J. F.; Marcos, A.; Marcos, N.; Bizarro, S.; Mano, F.

2015-12-01

During the day November 26, 2014, a scheduled cleanup of the woods took place around the GOA-UVa aerosol measurement station located at the campus of the University of Beira Interior (40° 16’30”N, 7°30’35”W, 704m a.s.l.), Covilhã, Portugal. This cleanup included excessive vegetation removal during the morning, using fossil fuel-burning machinery, and burning of the vegetation during the afternoon. In situ measurements of aerosol optical properties were made and this study aims the characterization of the evolution of aerosol properties during the day. The optical parameters were monitored using a 3-wavelength nephelometer and a 3-wavelength particle soot absorption photometer. Selective sampling/exclusion of the coarse particles was done each 5 minutes. The scattering and absorption Ångström exponents as well as the single scattering albedo were derived and fully analyzed. The scattering and absorption coefficients increased dramatically during the event, reaching values as high as 720.3 Mm-1 and 181.9 Mm-1, respectively, for the green wavelength and PM10 size fraction. The spectral behavior of these parameters also changed wildly along the day and an inversion of the slope from positive to negative in the case of the single scattering albedo was observed.

Experimental Modeling of the Effect of Terrain Slope on Marginal Burning

Treesearch

X. Zhou; S. Mahalingam; D. Weise

2005-01-01

A series of laboratory fire spread experiments were completed to analyze the effect of terrain slope on marginal burning behavior of live chaparral shrub fuels that grow in the mountains of southern California. We attempted to burn single species fuel beds of four common chaparral plants under various fuel bed configurations and ambient conditions. Seventy-three (or 42...

Burning high-level TRU waste in fusion fission reactors

NASA Astrophysics Data System (ADS)

Shen, Yaosong

2016-09-01

Recently, the concept of actinide burning instead of a once-through fuel cycle for disposing spent nuclear fuel seems to get much more attention. A new method of burning high-level transuranic (TRU) waste combined with Thorium-Uranium (Th-U) fuel in the subcritical reactors driven by external fusion neutron sources is proposed in this paper. The thorium-based TRU fuel burns all of the long-lived actinides via a hard neutron spectrum while outputting power. A one-dimensional model of the reactor concept was built by means of the ONESN_BURN code with new data libraries. The numerical results included actinide radioactivity, biological hazard potential, and much higher burnup rate of high-level transuranic waste. The comparison of the fusion-fission reactor with the thermal reactor shows that the harder neutron spectrum is more efficient than the soft. The Th-U cycle produces less TRU, less radiotoxicity and fewer long-lived actinides. The Th-U cycle provides breeding of 233U with a long operation time (>20 years), hence significantly reducing the reactivity swing while improving safety and burnup.

Emissions of polychlorinated dibenzodioxins and dibenzofurans and polychlorinated biphenyls from uncontrolled burning of garden and domestic waste (backyard burning).

PubMed

Hedman, Björn; Näslund, Morgan; Nilsson, Calle; Marklund, Stellan

2005-11-15

To assess emissions of dioxins (chlorinated dibenzodioxins and dibenzofurans) and PCB from uncontrolled domestic combustion of waste ("backyard burning"), test combustions in barrels and open fires were monitored. The waste fuels used were garden waste, paper, paper and plastic packaging, refuse-derived fuel (RDF), PVC, and electronic scrap. Combustions including PVC and electronic scrap emitted several orders of magnitude more dioxins than the other waste fuels. Emissions from the other fuels had considerable variations, but the levels were difficult to relate to waste composition. Emission factors of PCDD/F and PCB from the backyard burning ranged from 2.2 to 13 000 ng (WHO-TEQ)/kg. The levels found in ash usually were less than 5% of the total. For assessment of total emissions of dioxins and PCB from backyard burning of low and moderately contaminated wastes, an emission factor range of 4-72 ng (WHO-TEQ)/kg is suggested. These figures implythat combusting waste in the backyard could contribute substantially to total emissions, even if the amounts of fuel involved are equivalent to just a few tenths of a percent of the amounts combusted in municipal waste incinerators.

A Better Way to Burn Wood.

ERIC Educational Resources Information Center

Robison, Rita

1979-01-01

Wood pyrolysis is a process that burns wood without air, producing gas and oil that are then burned for heat. Now being tested at Maryville College, Tennessee, the process is expected to cut fuel costs, solve a waste disposal problem, and produce charcoal for sale. (Author/MLF)

The consequences of global biomass burning

NASA Technical Reports Server (NTRS)

Levine, Joel S.

1991-01-01

Global biomass burning encompasses forest burning for land clearing, the annual burning of grasslands, the annual burning of agricultural stubble and waste after harvests, and the burning of wood as fuel. These activities generate CO2, CH4 and other hydrocarbons, CO, H2, NO, NH3, and CH3Cl; of these, CO, CH4 and the hydrocarbons, and NO, are involved in the photochemical production of tropospheric O3, while NO is transformed to NO2 and then to nitric acid, which falls as acid rain. Biomass burning is also a major source of atmospheric particulates and aerosols which affect the transmission of incoming solar radiation and outgoing IR radiation through the atmosphere, with significant climatic effects.

Using Coupled Mesoscale Experiments and Simulations to Investigate High Burn-Up Oxide Fuel Thermal Conductivity

NASA Astrophysics Data System (ADS)

Teague, Melissa C.; Fromm, Bradley S.; Tonks, Michael R.; Field, David P.

2014-12-01

Nuclear energy is a mature technology with a small carbon footprint. However, work is needed to make current reactor technology more accident tolerant and to allow reactor fuel to be burned in a reactor for longer periods of time. Optimizing the reactor fuel performance is essentially a materials science problem. The current understanding of fuel microstructure have been limited by the difficulty in studying the structure and chemistry of irradiated fuel samples at the mesoscale. Here, we take advantage of recent advances in experimental capabilities to characterize the microstructure in 3D of irradiated mixed oxide (MOX) fuel taken from two radial positions in the fuel pellet. We also reconstruct these microstructures using Idaho National Laboratory's MARMOT code and calculate the impact of microstructure heterogeneities on the effective thermal conductivity using mesoscale heat conduction simulations. The thermal conductivities of both samples are higher than the bulk MOX thermal conductivity because of the formation of metallic precipitates and because we do not currently consider phonon scattering due to defects smaller than the experimental resolution. We also used the results to investigate the accuracy of simple thermal conductivity approximations and equations to convert 2D thermal conductivities to 3D. It was found that these approximations struggle to predict the complex thermal transport interactions between metal precipitates and voids.

Biomass Combustions and Burning Emissions Inferred from GOES Fire Radiative Power

NASA Astrophysics Data System (ADS)

Zhang, X.; Kondragunta, S.; Schmidt, C.

2007-12-01

Biomass burning significantly affects air quality and climate changes. Current estimates of burning emissions are rather imprecise and vary markedly with different methodologies. This paper investigates biomass burning consumption and emissions using GOES (Geostationary Operational Environmental Satellites) WF_ABBA (Wildfire Automated Biomass Burning Algorithm) fire product. In doing this, we establish a set of representatives in diurnal patterns of half-hourly GOES Fire Radiative Power (FRP) for various ecosystems. The representative patterns are used to fill the missed and poor observations of half hourly FRP in GOES fire data for individual fire pixels. The simulated FRP is directly applied to the calculation of the biomass combusted during fire activities. The FRP-based biomass combustion is evaluated using the estimates using a traditional model which integrates burned area, fuel loading, and combustion factor. In the traditional model calculation, we derive burned areas from GOES WF_ABBA fire size. Fuel loading includes three different types (1) MODIS Vegetation Property-based Fuel System (MVPFS), (2) National Dangerous Rating Systems (NFDRS), and (3) the Fuel Characteristic Classification System (FCCS). By comparing the biomass combustions across the Contiguous United States (CONUS) from 2003-2005, we conclude that FRP is an effective tool to estimate the biomass burning emissions. Finally, we examine the temporal and spatial patterns in biomass combustions and emissions (PM2.5, CO, NH3) across the CONUS.

Heterogeneity in fire severity within early season and late season prescribed burns in a mixed-conifer forest

USGS Publications Warehouse

Knapp, E.E.; Keeley, J.E.

2006-01-01

Structural heterogeneity in forests of the Sierra Nevada was historically produced through variation in fire regimes and local environmental factors. The amount of heterogeneity that prescription burning can achieve might now be more limited owing to high fuel loads and increased fuel continuity. Topography, woody fuel loading, and vegetative composition were quantified in plots within replicated early and late season burn units. Two indices of fire severity were evaluated in the same plots after the burns. Scorch height ranged from 2.8 to 25.4 m in early season plots and 3.1 to 38.5 m in late season plots, whereas percentage of ground surface burned ranged from 24 to 96% in early season plots and from 47 to 100% in late season plots. Scorch height was greatest in areas with steeper slopes, higher basal area of live trees, high percentage of basal area composed of pine, and more small woody fuel. Percentage of area burned was greatest in areas with less bare ground and rock cover (more fuel continuity), steeper slopes, and units burned in the fall (lower fuel moisture). Thus topographic and biotic factors still contribute to the abundant heterogeneity in fire severity with prescribed burning, even under the current high fuel loading conditions. Burning areas with high fuel loads in early season when fuels are moister may lead to patterns of heterogeneity in fire effects that more closely approximate the expected patchiness of historical fires.

Characteristics of Ambient Black Carbon Mass and Size-Resolved Particle Number Concentrations during Corn Straw Open-Field Burning Episode Observations at a Rural Site in Southern Taiwan.

PubMed

Cheng, Yu-Hsiang; Yang, Li-Sing

2016-07-08

Information on the effect of open-field burning of agricultural residues on ambient black carbon (BC) mass and size-resolved particle number concentrations is scarce. In this study, to understand the effect of such open-field burning on short-term air quality, real-time variations of the BC mass and size-resolved particle number concentrations were monitored before and during a corn straw open-field burning episode at a rural site. Correlations between the BC mass and size-resolved particle number concentrations during the episode were investigated. Moreover, the particle number size distribution and absorption Ångström exponent were determined for obtaining the characteristics of aerosol emissions from the corn straw open-field burning. The results can be used to address public health concerns and as a reference for managing similar episodes of open-field burning of agricultural residues.

Mutagenicity and Lung Toxicity of Smoldering vs. Flaming Emissions from Various Biomass Fuels: Implications for Health Effects from Wildland Fires.

PubMed

Kim, Yong Ho; Warren, Sarah H; Krantz, Q Todd; King, Charly; Jaskot, Richard; Preston, William T; George, Barbara J; Hays, Michael D; Landis, Matthew S; Higuchi, Mark; DeMarini, David M; Gilmour, M Ian

2018-01-24

The increasing size and frequency of wildland fires are leading to greater potential for cardiopulmonary disease and cancer in exposed populations; however, little is known about how the types of fuel and combustion phases affect these adverse outcomes. We evaluated the mutagenicity and lung toxicity of particulate matter (PM) from flaming vs. smoldering phases of five biomass fuels, and compared results by equal mass or emission factors (EFs) derived from amount of fuel consumed. A quartz-tube furnace coupled to a multistage cryotrap was employed to collect smoke condensate from flaming and smoldering combustion of red oak, peat, pine needles, pine, and eucalyptus. Samples were analyzed chemically and assessed for acute lung toxicity in mice and mutagenicity in Salmonella . The average combustion efficiency was 73 and 98% for the smoldering and flaming phases, respectively. On an equal mass basis, PM from eucalyptus and peat burned under flaming conditions induced significant lung toxicity potencies (neutrophil/mass of PM) compared to smoldering PM, whereas high levels of mutagenicity potencies were observed for flaming pine and peat PM compared to smoldering PM. When effects were adjusted for EF, the smoldering eucalyptus PM had the highest lung toxicity EF (neutrophil/mass of fuel burned), whereas smoldering pine and pine needles had the highest mutagenicity EF. These latter values were approximately 5, 10, and 30 times greater than those reported for open burning of agricultural plastic, woodburning cookstoves, and some municipal waste combustors, respectively. PM from different fuels and combustion phases have appreciable differences in lung toxic and mutagenic potency, and on a mass basis, flaming samples are more active, whereas smoldering samples have greater effect when EFs are taken into account. Knowledge of the differential toxicity of biomass emissions will contribute to more accurate hazard assessment of biomass smoke exposures. https://doi.org/10

High burn-up spent nuclear fuel transport reliability investigation

DOE PAGES

Wang, Jy-An; Wang, Hong; Jiang, Hao; ...

2018-04-15

Transportation packages for spent nuclear fuel (SNF) must meet safety requirements under normal and accident conditions as specified by federal regulations. During road or rail transportation, SNF will experience unique conditions that could affect the structural integrity of the cladding due to vibrational and impact loading. Lack of SNF inertia-induced dynamic fatigue data, especially for the high burn-up (HBU) SNF systems, has brought significant challenges to quantify the reliability of SNF during transportation with a high degree of confidence. To address this shortcoming, Oak Ridge National Laboratory (ORNL) developed a SNF vibration testing protocol without fuel pellets removal, which hasmore » provided significant insight regarding the dynamics of mechanical interactions between pellet and cladding. This research has provided a detailed understanding about the effect of loading rate and loading mode on the fatigue damage evolution of HBU SNF under normal conditions of transport (NCT). Static and dynamic loading experimental data were generated for SNF under simulated transportation environments using a cyclic integrated reversible-bending fatigue tester (CIRFT), an enabling hot-cell testing technology developed at ORNL. SNF flexural tensile strength and fatigue S-N data from pressurized water reactors (PWRs) and boiling water reactor (BWR) HBU SNF are presented in this paper, including the potential effects of pellet-cladding interface bonding, hydride reorientation, and thermal annealing to SNF vibration reliability. The data presented here can be used to meet the nuclear industry and U.S. Nuclear Regulatory Commission needs in safety of SNF transportation operations.« less

High burn-up spent nuclear fuel transport reliability investigation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jy-An; Wang, Hong; Jiang, Hao

Transportation packages for spent nuclear fuel (SNF) must meet safety requirements under normal and accident conditions as specified by federal regulations. During road or rail transportation, SNF will experience unique conditions that could affect the structural integrity of the cladding due to vibrational and impact loading. Lack of SNF inertia-induced dynamic fatigue data, especially for the high burn-up (HBU) SNF systems, has brought significant challenges to quantify the reliability of SNF during transportation with a high degree of confidence. To address this shortcoming, Oak Ridge National Laboratory (ORNL) developed a SNF vibration testing protocol without fuel pellets removal, which hasmore » provided significant insight regarding the dynamics of mechanical interactions between pellet and cladding. This research has provided a detailed understanding about the effect of loading rate and loading mode on the fatigue damage evolution of HBU SNF under normal conditions of transport (NCT). Static and dynamic loading experimental data were generated for SNF under simulated transportation environments using a cyclic integrated reversible-bending fatigue tester (CIRFT), an enabling hot-cell testing technology developed at ORNL. SNF flexural tensile strength and fatigue S-N data from pressurized water reactors (PWRs) and boiling water reactor (BWR) HBU SNF are presented in this paper, including the potential effects of pellet-cladding interface bonding, hydride reorientation, and thermal annealing to SNF vibration reliability. The data presented here can be used to meet the nuclear industry and U.S. Nuclear Regulatory Commission needs in safety of SNF transportation operations.« less

Chemistry of burning the forest floor during the FROSTFIRE experimental burn, interior Alaska, 1999

USGS Publications Warehouse

Harden, J.W.; Neff, J.C.; Sandberg, D.V.; Turetsky, M.R.; Ottmar, R.; Gleixner, G.; Fries, T.L.; Manies, K.L.

2004-01-01

Wildfires represent one of the most common disturbances in boreal regions, and have the potential to reduce C, N, and Hg stocks in soils while contributing to atmospheric emissions. Organic soil layers of the forest floor were sampled before and after the FROSTFIRE experimental burn in interior Alaska, and were analyzed for bulk density, major and trace elements, and organic compounds. Concentrations of carbon, nutrients, and several major and trace elements were significantly altered by the burn. Emissions of C, N, and Hg, estimated from chemical mass balance equations using Fe, Al, and Si as stable constituents, indicated that 500 to 900 g C and up to 0 to 4 ?? 10-4 g Hg/M2 were lost from the site. Calculations of nitrogen loss range from -4 to +6 g/m2 but were highly variable (standard deviation 19), with some samples showing increased N concentrations post-burn potentially from canopy ash. Noncombustible major nutrients such as Ca and K also were inherited from canopy ash. Thermogravimetry indicates a loss of thermally labile C and increase of lignin-like C in char and ash relative to unburned counterparts. Overall, atmospheric impacts of boreal fires include large emissions of C, N and Hg that vary greatly as a function of severe fire weather and its access to deep organic layers rich in C, N, and Hg. In terrestrial systems, burning rearranges the vertical distribution of nutrients in fuels and soils, the proximity of nutrients and permafrost to surface biota, and the chemical composition of soil including its nutrient and organic constituents, all of which impact C cycling. Copyright 2004 by the American Geophysical Union.

Effect of secondary organic aerosol coating thickness on the real-time detection and characterization of biomass-burning soot by two particle mass spectrometers

DOE PAGES

Ahern, Adam T.; Subramanian, Ramachandran; Saliba, Georges; ...

2016-12-22

Biomass burning is a large source of light-absorbing refractory black carbon (rBC) particles with a wide range of morphologies and sizes. The net radiative forcing from these particles is strongly dependent on the amount and composition of non-light-absorbing material internally mixed with the rBC and on the morphology of the mixed particles. Understanding how the mixing state and morphology of biomass-burning aerosol evolves in the atmosphere is critical for constraining the influence of these particles on radiative forcing and climate. We investigated the response of two commercial laser-based particle mass spectrometers, the vacuum ultraviolet (VUV) ablation LAAPTOF and the IRmore » vaporization SP-AMS, to monodisperse biomass-burning particles as we sequentially coated the particles with secondary organic aerosol (SOA) from α-pinene ozonolysis. We studied three mobility-selected soot core sizes, each with a number of successively thicker coatings of SOA applied. Using IR laser vaporization, the SP-AMS had different changes in sensitivity to rBC compared to potassium as a function of applied SOA coatings. We show that this is due to different effective beam widths for the IR laser vaporization region of potassium versus black carbon. The SP-AMS's sensitivity to black carbon (BC) mass was not observed to plateau following successive SOA coatings, despite achieving high OA : BC mass ratios greater than 9. We also measured the ion fragmentation pattern of biomass-burning rBC and found it changed only slightly with increasing SOA mass. The average organic matter ion signal measured by the LAAPTOF demonstrated a positive correlation with the condensed SOA mass on individual particles, despite the inhomogeneity of the particle core compositions. This demonstrates that the LAAPTOF can obtain quantitative mass measurements of aged soot-particle composition from realistic biomass-burning particles with complex morphologies and composition.« less

Effect of secondary organic aerosol coating thickness on the real-time detection and characterization of biomass-burning soot by two particle mass spectrometers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahern, Adam T.; Subramanian, Ramachandran; Saliba, Georges

Biomass burning is a large source of light-absorbing refractory black carbon (rBC) particles with a wide range of morphologies and sizes. The net radiative forcing from these particles is strongly dependent on the amount and composition of non-light-absorbing material internally mixed with the rBC and on the morphology of the mixed particles. Understanding how the mixing state and morphology of biomass-burning aerosol evolves in the atmosphere is critical for constraining the influence of these particles on radiative forcing and climate. We investigated the response of two commercial laser-based particle mass spectrometers, the vacuum ultraviolet (VUV) ablation LAAPTOF and the IRmore » vaporization SP-AMS, to monodisperse biomass-burning particles as we sequentially coated the particles with secondary organic aerosol (SOA) from α-pinene ozonolysis. We studied three mobility-selected soot core sizes, each with a number of successively thicker coatings of SOA applied. Using IR laser vaporization, the SP-AMS had different changes in sensitivity to rBC compared to potassium as a function of applied SOA coatings. We show that this is due to different effective beam widths for the IR laser vaporization region of potassium versus black carbon. The SP-AMS's sensitivity to black carbon (BC) mass was not observed to plateau following successive SOA coatings, despite achieving high OA : BC mass ratios greater than 9. We also measured the ion fragmentation pattern of biomass-burning rBC and found it changed only slightly with increasing SOA mass. The average organic matter ion signal measured by the LAAPTOF demonstrated a positive correlation with the condensed SOA mass on individual particles, despite the inhomogeneity of the particle core compositions. This demonstrates that the LAAPTOF can obtain quantitative mass measurements of aged soot-particle composition from realistic biomass-burning particles with complex morphologies and composition.« less

Cooking fuel choices and garbage burning practices as determinants of birth weight: a cross-sectional study in Accra, Ghana

PubMed Central

2012-01-01

Background Effect of indoor air pollution (IAP) on birth weight remains largely unexplored but yet purported as the most important environmental exposure for pregnant women in developing countries due to the effects of second-hand smoke. We investigated the associations between the determinants of indoor air quality in households and birth weight. Methods A cross-sectional study of 592 mothers and their newborns using postnatal services at the Korle Bu Teaching Hospital located in Accra, Ghana was conducted in 2010 to collect information on characteristics of indoor environment and other potential determinants of fetal growth. Birth weight was recorded from hospital records. Results Household cooking fuel choices and garbage burning practices were determinants of birth weight. Multivariate linear regression analysis adjusting for age, social class, marital status and gravidity of mothers, and sex of neonate resulted in a 243g (95% CI: 496, 11) and 178g (95% CI: 421, 65) reduction in birth weight for use of charcoal, and garbage burning respectively compared with use of LPG only. The estimated reductions in birth weight was not statistically significant. Applying the ordinal scale exposure parameter nonetheless revealed a significant exposure-response relationship between maternal exposures from charcoal use and garbage burning, and birth weight. Generalized linear models adjusting for confounders resulted in a 41% (risk ratio [RR] = 1.41; 95% CI: 0.62, 3.23) and 195% (RR=2.95; 95% CI: 1.10, 7.92) increase in the risk of low birth weight (LBW) for use of charcoal, and garbage burning respectively compared with use of LPG only. A combination of charcoal use and household garbage burning during pregnancy on fetal growth resulted in a 429g (95% CI: 259, 599) reduction in birth weight and 316% (RR=4.16; 95% CI: 2.02, 8.59) excess risk of LBW. Sensitivity analysis performed by restricting the analysis to term births produced similar results. Conclusions Maternal use of

Assault by burning in Jordan.

PubMed

Haddadin, W

2012-12-31

Criminal attacks by burns on women in Jordan are highlighted in this retrospective study carried out of all proved cases of criminal burns in female patients treated at the burn unit of the Royal Rehabilitation Center in Jordan between January 2005 and June 2012. Thirteen patients were included in our study, out of a total of 550 patients admitted, all in the age range of 16-45 yr. Of these 13 women, six were burned by acid throwing, five by hot water, and two by direct flames from fuel thrown over them. Burn percentage ranged from 15 to 75% of the total body surface area, with involvement in most cases of the face and upper trunk. The mean hospital stay was 33 days and the mortality rate was 3/13, i.e. 23%. Violence against women exists in Jordanian society, yet burning assaults are rare. Of these, burning by throwing acid is the most common and most disfiguring act, with a higher mortality rate in domestic environments.

Burning of olive tree branches: a major organic aerosol source in the Mediterranean

NASA Astrophysics Data System (ADS)

Kostenidou, E.; Kaltsonoudis, C.; Tsiflikiotou, M.; Louvaris, E.; Russell, L. M.; Pandis, S. N.

2013-09-01

Aerosol produced during the burning of olive tree branches was characterized with both direct source sampling (using a mobile smog chamber) and with ambient measurements during the burning season. The fresh particles were composed of 80% organic matter, 8-10% black carbon (BC), 5% potassium, 3-4% sulfate, 2-3% nitrate and 0.8% chloride. Almost half of the fresh olive tree branches burning organic aerosol (otBB-OA) consisted of alkane groups. Their mode diameter was close to 70 nm. The oxygen to carbon (O : C) ratio of the fresh otBB-OA was 0.29 ± 0.04. The mass fraction of levoglucosan in PM1 was 0.034-0.043, relatively low in comparison with most fuel types. This may lead to an underestimation of the otBB-OA contribution if levoglucosan is being used as a wood burning tracer. Chemical aging was observed during smog chamber experiments, as f44 and O : C ratio increased, due to reactions with OH radicals and O3. The otBB-OA AMS mass spectrum differs from the other published biomass burning spectra, with a main difference at m/z 60, used as levoglucosan tracer. In addition to particles, volatile organic compounds (VOCs) such as methanol, acetonitrile, acrolein, benzene, toluene and xylenes are also emitted. Positive matrix factorization (PMF) was applied to the ambient organic aerosol data and 3 factors could be identified: OOA (oxygenated organic aerosol, 55%), HOA (hydrocarbon-like organic aerosol, 11.3%) and otBB-OA 33.7%. The fresh chamber otBB-OA AMS spectrum is close to the PMF otBB-OA spectrum and resembles the ambient mass spectrum during olive tree branches burning periods. We estimated an otBB-OA emission factor of 3.5 ± 0.9 g kg-1. Assuming that half of the olive tree branches pruned is burned in Greece, 2300 ± 600 tons of otBB-OA are emitted every year. This activity is one of the most important fine aerosol sources during the winter months in Mediterranean countries.

Burning of olive tree branches: a major organic aerosol source in the Mediterranean

NASA Astrophysics Data System (ADS)

Kostenidou, E.; Kaltsonoudis, C.; Tsiflikiotou, M.; Louvaris, E.; Russell, L. M.; Pandis, S. N.

2013-03-01

Aerosol produced during the burning of olive tree branches was characterized with both direct source-sampling (using a mobile smog chamber) and with ambient measurements during the burning season. The fresh particles were composed of 80% organic matter, 8-10% black carbon (BC), 5% potassium, 3-4% sulfate, 2-3% nitrate and 0.8% chloride. Almost half of the fresh olive tree branches burning organic aerosol (otBB-OA) consisted of alkane groups. Their mode diameter was close to 70 nm. The oxygen to carbon (O:C) ratio of the fresh otBB-OA was 0.29 ± 0.04. The mass fraction of levoglucosan in PM1 was 0.034-0.043, relatively low in comparison with most fuel types. This may lead to an underestimation of the otBB-OA contribution if levoglucosan is being used as a wood burning tracer. Chemical aging was observed during smog chamber experiments, as f44 and O:C ratio increased, due to reactions with OH radicals and O3. The otBB-OA AMS mass spectrum differs from the other published biomass burning spectra, with a main difference at m/z 60, used as levoglucosan tracer. In addition to particles, volatile organic compounds (VOCs) such as methanol, acetonitrile, acrolein, benzene, toluene and xylenes are also emitted. Positive matrix factorization (PMF) was applied to the ambient organic aerosol data and 3 factors could be identified: OOA (oxygenated organic aerosol, 55%), HOA (hydrocarbon-like organic aerosol, 11.3%) and otBB-OA 33.7%. The fresh chamber otBB-OA AMS spectrum is close to the PMF otBB-OA spectrum and resembles the ambient mass spectrum during olive tree branches burning periods. We estimated an otBB-OA emission factor of 3.5 ± 0.2 g kg-1. Assuming that half of the olive tree branches pruned is burned in Greece 2280 ± 140 tons of otBB-OA are emitted every year. This activity is one of the most important fine aerosol sources during the winter months in the Mediterranean countries.

Fuel loading following fuel-reduction treatments and impacts from natural disturbances

Treesearch

Ross J. Phillips; Thomas A. Waldrop

2013-01-01

A long-term study of fuel-reduction treatments (mechanical fuel removal, prescribed burning, and the combination of mechanical treatment and burning) was begun in 2000 and 2001 for sites located in the Piedmont of South Carolina and the Southern Appalachian Mountains of North Carolina, respectively. During this time multiple natural disturbances [southern pine beetle...

Fuel loads, fire regimes, and post-fire fuel dynamics in Florida Keys pine forests

USGS Publications Warehouse

Sah, J.P.; Ross, M.S.; Snyder, J.R.; Koptur, S.; Cooley, H.C.

2006-01-01

In forests, the effects of different life forms on fire behavior may vary depending on their contributions to total fuel loads. We examined the distribution of fuel components before fire, their effects on fire behavior, and the effects of fire on subsequent fuel recovery in pine forests within the National Key Deer Refuge in the Florida Keys. We conducted a burning experiment in six blocks, within each of which we assigned 1-ha plots to three treatments: control, summer, and winter burn. Owing to logistical constraints, we burned only 11 plots, three in winter and eight in summer, over a 4-year period from 1998 to 2001. We used path analysis to model the effects of fuel type and char height, an indicator of fire intensity, on fuel consumption. Fire intensity increased with surface fuel loads, but was negatively related to the quantity of hardwood shrub fuels, probably because these fuels are associated with a moist microenvironment within hardwood patches, and therefore tend to resist fire. Winter fires were milder than summer fires, and were less effective at inhibiting shrub encroachment. A mixed seasonal approach is suggested for fire management, with burns applied opportunistically under a range of winter and summer conditions, but more frequently than that prevalent in the recent past. ?? IAWF 2006.

Intense atmospheric pollution modifies weather: a case of mixed biomass burning with fossil fuel combustion pollution in eastern China

NASA Astrophysics Data System (ADS)

Ding, A. J.; Fu, C. B.; Yang, X. Q.; Sun, J. N.; Petäjä, T.; Kerminen, V.-M.; Wang, T.; Xie, Y.; Herrmann, E.; Zheng, L. F.; Nie, W.; Liu, Q.; Wei, X. L.; Kulmala, M.

2013-10-01

The influence of air pollutants, especially aerosols, on regional and global climate has been widely investigated, but only a very limited number of studies report their impacts on everyday weather. In this work, we present for the first time direct (observational) evidence of a clear effect of how a mixed atmospheric pollution changes the weather with a substantial modification in the air temperature and rainfall. By using comprehensive measurements in Nanjing, China, we found that mixed agricultural burning plumes with fossil fuel combustion pollution resulted in a decrease in the solar radiation intensity by more than 70%, a decrease in the sensible heat by more than 85%, a temperature drop by almost 10 K, and a change in rainfall during both daytime and nighttime. Our results show clear air pollution-weather interactions, and quantify how air pollution affects weather via air pollution-boundary layer dynamics and aerosol-radiation-cloud feedbacks. This study highlights cross-disciplinary needs to investigate the environmental, weather and climate impacts of the mixed biomass burning and fossil fuel combustion sources in East China.

Global biomass burning - Atmospheric, climatic, and biospheric implications

NASA Technical Reports Server (NTRS)

Levine, Joel S.

1991-01-01

On a global scale, the total biomass consumed by annual burning is about 8680 million tons of dry material; the estimated total biomass consumed by the burning of savanna grasslands, at 3690 million tons/year, exceeds all other biomass burning (BMB) components. These components encompass agricultural wastes burning, forest burning, and fuel wood burning. BMB is not restricted to the tropics, and is largely anthropogenic. Satellite measurements indicate significantly increased tropospheric concentrations of CO and ozone associated with BMB. BMB significantly enhances the microbial production and emission of NO(x) from soils, and of methane from wetlands.

Near-real-time global biomass burning emissions product from geostationary satellite constellation

NASA Astrophysics Data System (ADS)

Zhang, Xiaoyang; Kondragunta, Shobha; Ram, Jessica; Schmidt, Christopher; Huang, Ho-Chun

2012-07-01

Near-real-time estimates of biomass burning emissions are crucial for air quality monitoring and forecasting. We present here the first near-real-time global biomass burning emission product from geostationary satellites (GBBEP-Geo) produced from satellite-derived fire radiative power (FRP) for individual fire pixels. Specifically, the FRP is retrieved using WF_ABBA V65 (wildfire automated biomass burning algorithm) from a network of multiple geostationary satellites. The network consists of two Geostationary Operational Environmental Satellites (GOES) which are operated by the National Oceanic and Atmospheric Administration, the Meteosat second-generation satellites (Meteosat-09) operated by the European Organisation for the Exploitation of Meteorological Satellites, and the Multifunctional Transport Satellite (MTSAT) operated by the Japan Meteorological Agency. These satellites observe wildfires at an interval of 15-30 min. Because of the impacts from sensor saturation, cloud cover, and background surface, the FRP values are generally not continuously observed. The missing observations are simulated by combining the available instantaneous FRP observations within a day and a set of representative climatological diurnal patterns of FRP for various ecosystems. Finally, the simulated diurnal variation in FRP is applied to quantify biomass combustion and emissions in individual fire pixels with a latency of 1 day. By analyzing global patterns in hourly biomass burning emissions in 2010, we find that peak fire season varied greatly and that annual wildfires burned 1.33 × 1012 kg dry mass, released 1.27 × 1010 kg of PM2.5 (particulate mass for particles with diameter <2.5 μm) and 1.18 × 1011kg of CO globally (excluding most parts of boreal Asia, the Middle East, and India because of no coverage from geostationary satellites). The biomass burning emissions were mostly released from forest and savanna fires in Africa, South America, and North America. Evaluation of

Transverse liquid fuel jet breakup, burning, and ignition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Hsi-shang

1990-01-01

An analytical/numerical study of the breakup, burning, and ignition of liquid fuels injected transversely into a hot air stream is conducted. The non-reacting liquid jet breakup location is determined by the local sonic point criterion first proposed by Schetz, et al. (1980). Two models, one employing analysis of an elliptical jet cross-section and the other employing a two-dimensional blunt body to represent the transverse jet, have been used for sonic point calculations. An auxiliary criterion based on surface tension stability is used as a separate means of determining the breakup location. For the reacting liquid jet problem, a diffusion flamemore » supported by a one-step chemical reaction within the gaseous boundary layer is solved along the ellipse surface in subsonic crossflow. Typical flame structures and concentration profiles have been calculated for various locations along the jet cross-section as a function of upstream Mach numbers. The integrated reaction rate along the jet cross-section is used to predict ignition position, which is found to be situated near the stagnation point. While a multi-step reaction is needed to represent the ignition process more accurately, the present calculation does yield reasonable predictions concerning ignition along a curved surface.« less

Forest fires in Mediterranean countries: CO2 emissions and mitigation possibilities through prescribed burning.

PubMed

Vilén, Terhi; Fernandes, Paulo M

2011-09-01

Forest fires are an integral part of the ecology of the Mediterranean Basin; however, fire incidence has increased dramatically during the past decades and fire is expected to become more prevalent in the future due to climate change. Fuel modification by prescribed burning reduces the spread and intensity potential of subsequent wildfires. We used the most recently published data to calculate the average annual wildfire CO(2) emissions in France, Greece, Italy, Portugal and Spain following the IPCC guidelines. The effect of prescribed burning on emissions was calculated for four scenarios of prescribed burning effectiveness based on data from Portugal. Results show that prescribed burning could have a considerable effect on the carbon balance of the land use, land-use change and forestry (LULUCF) sector in Mediterranean countries. However, uncertainty in emission estimates remains large, and more accurate data is needed, especially regarding fuel load and fuel consumption in different vegetation types and fuel layers and the total area protected from wildfire per unit area treated by prescribed burning, i.e. the leverage of prescribed burning.

The formation of light absorbing insoluble organic compounds from the reaction of biomass burning precursors and Fe(III)

NASA Astrophysics Data System (ADS)

Lavi, Avi; Lin, Peng; Bhaduri, Bhaskar; Laskin, Alexander; Rudich, Yinon

2017-04-01

Dust particles and volatile organic compounds from fuel or biomass burning are two major components that affect air quality in urban polluted areas. We characterized the products from the reaction of soluble Fe(III), a reactive transition metal originating from dust particles dissolution processes, with phenolic compounds , namely, guaiacol, syringol, catechol, o- and p- cresol that are known products of incomplete fuel and biomass combustion but also from other natural sources such as humic compounds degradation. We found that under acidic conditions comparable to those expected on a dust particle surface, phenolic compounds readily react with dissolved Fe(III), leading to the formation of insoluble polymeric compounds. We characterized the insoluble products by x-ray photoelectron microscopy, UV-Vis spectroscopy, mass spectrometry, elemental analysis and thermo-gravimetric analysis. We found that the major chromophores formed are oligomers (from dimers to pentamers) of the reaction precursors that efficiently absorb light between 300nm and 500nm. High variability of the mass absorption coefficient of the reaction products was observed with catechol and guaiacol showing high absorption at the 300-500nm range that is comparable to that of brown carbon (BrC) from biomass burning studies. The studied reaction is a potential source for the in-situ production of secondary BrC material under dark conditions. Our results suggest a reaction path for the formation of bio-available iron in coastal polluted areas where dust particles mix with biomass burning pollution plumes. Such mixing can occur, for instance in the coast of West Africa or North Africa during dust and biomass burning seasons

Evaluation of burn injuries related to liquefied petroleum gas.

PubMed

Tarim, Mehmet Akin

2014-01-01

Liquefied petroleum gas (LPG) is a fuel that is widely used for domestic, agricultural, and industrial purposes. LPG is also commonly used in restaurants, industries, and cars; however, the home continues to be the main site for accidents. In Turkey, the increased usage of LPG as a cooking or heating fuel has resulted in many burn injuries from LPG mishaps. Between January 2000 and June 2011, 56 LPG-burned patients were compared with 112 flame-burned patients. There were no significant differences with respect to the mean age, sex, hospitalization time, and mortality in both groups. In the LPG-caused burn cases, 41 burns (73.2%) occurred at home, seven (12.5) were work-related mishaps, and eight (14.3) were associated with car accidents. The majority of the LPG burns (82%, 46 patients) resulted from a gas leak, and 18% of them were related to the failure to close LPG tubes in the patients' kitchens (10 patients). Burns to the face and neck (82 vs 67%, P = .039) and upper (62 vs 23%, P = .000) and lower (70 vs 45%, P = .002) extremities were significantly higher in LPG-caused burn cases than flame-burned cases. General awareness regarding the risk of LPG and first aid for burns appears to be lacking. The LPG delivery system should be standardized throughout countries that widely use LPG.

Preventable burns associated with the misuse of gasoline.

PubMed

Barillo, D J; Stetz, C K; Zak, A L; Shirani, K Z; Goodwin, C W

1998-08-01

Gasoline is intended for use as a motor fuel, but the universal availability of gasoline in the home encourages misuse as a solvent, insecticide, accelerant or cleaning solution. The careless or inappropriate use of gasoline may result in burn injury. We examined the circumstance of gasoline-related injury in a population admitted to one burn centre to determine the potential for burn prevention efforts. A retrospective review of all burn admissions to one centre for the years 1978 to 1996 demonstrated hat 1011 of 4339 acute admissions (23.3%) were gasoline-related. This group had an average total burn size of 29.8% total body surface (TBSA) and an average full thickness injury of 14.4% TBSA. There were 144 fatalities resulting from gasoline-associated burn injury. Where such determination could be made, the use of gasoline was judged to be inappropriate or unsafe in 687 of 788 cases (87.1%). Ninety of 144 fatalities (62.5%) were associated with inappropriate or unsafe use of gasoline. The careless or inappropriate use of gasoline poses significant risk of burn injury. The indoor use of gasoline, as well as use of gasoline for purposes other than as a motor fuel, should be strongly discouraged.

Mobilizable RDF/d-RDF burning program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niemann, K.; Campbell, J.

1982-03-01

The Mobilizable RDF/d-RDF Burning Program was conceived to promote the utilization of refuse-derived fuels (RDF) as a supplement to existing fossil fuel sources in industrial-sized boilers. The program explores the design, development, and eventual construction of densified-RDF (d-RDF) for use in boiler combustion testing as a supplement to stoker coal or wood wastes. The equipment would be mounted on trailers and assembled and operated at preselected sites throughout the country where approximately 750 tons of RDF would be produced and test burned in a local boiler. The equipment, to include a transportable RDF boiler metering and feed system, would thenmore » be moved and operated at two to three test sites annually. The program is intended to encourage the construction of permanent resource recovery facilities by involving local waste handling groups in operating the equipment and producing fuel, and potential local fuel users in testing the fuel in their boilers. The Mobilizable Program was developed from two separate tasks. The first task developed the concept behind the program and defined its operational and organizational structure. The second task, a follow-up to the first, was intended principally to finalize test locations, develop equipment designs and specifications, and formalize a management program. This report summarizes the principal findings of both tasks. It identifies the criteria used to identify test locations, outlines the program's management structure, presents design and performance specifications for both the fuel production equipment and boiler fuel feed systems, and provides a detailed evaluation of the parameters involved in burning RDF in industrial-sized boilers. Final conclusions and recommendations identify problem areas encountered in the program, and discuss possible future directions for such a program.« less

Scheduling prescribed burns for hazard reduction in the southeast

Treesearch

Stephen S. Sackett

1975-01-01

Twelve-year studies in the southeastern Coastal Plain revealed that pine stands should be burned every three years to reduce natural fuels and thus forestall damage from possible wildfires. Rates of overstory growth were not significantly different in burned and unburned stands. Guidelines for prescribed burning of pine stands in this region are presented.

Lubricating Oil Burn-Off in Coast Guard Power Plants

DTIC Science & Technology

1975-02-01

of the in-line fuel filters and wear of the fuel pumps . The overwhelming majority of tests performed by others in L• lube oil burn-off programs...February 1975 IAJBRICATING OIL BURN-OFF IN 6. perfarming Organization Code COAST GUARD POWER PLANTS ___________A. Performing Organization Report No. 7...Authorls) J.R. Hobbs and R. A. WalterDOTC-JC76 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) U.S. Department of Transportation

MSFR TRU-burning potential and comparison with an SFR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fiorina, C.; Cammi, A.; Franceschini, F.

2013-07-01

The objective of this work is to evaluate the Molten Salt Fast Reactor (MSFR) potential benefits in terms of transuranics (TRU) burning through a comparative analysis with a sodium-cooled FR. The comparison is based on TRU- and MA-burning rates, as well as on the in-core evolution of radiotoxicity and decay heat. Solubility issues limit the TRU-burning rate to 1/3 that achievable in traditional low-CR FRs (low-Conversion-Ratio Fast Reactors). The softer spectrum also determines notable radiotoxicity and decay heat of the equilibrium actinide inventory. On the other hand, the liquid fuel suggests the possibility of using a Pu-free feed composed onlymore » of Th and MA (Minor Actinides), thus maximizing the MA burning rate. This is generally not possible in traditional low-CR FRs due to safety deterioration and decay heat of reprocessed fuel. In addition, the high specific power and the lack of out-of-core cooling times foster a quick transition toward equilibrium, which improves the MSFR capability to burn an initial fissile loading, and makes the MSFR a promising system for a quick (i.e., in a reactor lifetime) transition from the current U-based fuel cycle to a novel closed Th cycle. (authors)« less

Assault by burning in Jordan

PubMed Central

Haddadin, W.

2012-01-01

Summary Criminal attacks by burns on women in Jordan are highlighted in this retrospective study carried out of all proved cases of criminal burns in female patients treated at the burn unit of the Royal Rehabilitation Center in Jordan between January 2005 and June 2012. Thirteen patients were included in our study, out of a total of 550 patients admitted, all in the age range of 16-45 yr. Of these 13 women, six were burned by acid throwing, five by hot water, and two by direct flames from fuel thrown over them. Burn percentage ranged from 15 to 75% of the total body surface area, with involvement in most cases of the face and upper trunk. The mean hospital stay was 33 days and the mortality rate was 3/13, i.e. 23%. Violence against women exists in Jordanian society, yet burning assaults are rare. Of these, burning by throwing acid is the most common and most disfiguring act, with a higher mortality rate in domestic environments. PMID:23766757

Role of burning season on initial understory vegetation response to prescribed fire in a mixed conifer forest

USGS Publications Warehouse

Knapp, E.E.; Schwilk, D.W.; Kane, J.M.; Keeley, J.E.

2007-01-01

Although the majority of fires in the western United States historically occurred during the late summer or early fall when fuels were dry and plants were dormant or nearly so, early-season prescribed burns are often ignited when fuels are still moist and plants are actively growing. The purpose of this study was to determine if burn season influences postfire vegetation recovery. Replicated early-season burn, late-season burn, and unburned control units were established in a mixed conifer forest, and understory vegetation was evaluated before and after treatment. Vegetation generally recovered rapidly after prescribed burning. However, late-season burns resulted in a temporary but significant drop in cover and a decline in species richness at the 1 m 2 scale in the following year. For two of the several taxa that were negatively affected by burning, the reduction in frequency was greater after late-season than early-season burns. Early-season burns may have moderated the effect of fire by consuming less fuel and lessening the amount of soil heating. Our results suggest that, when burned under high fuel loading conditions, many plant species respond more strongly to differences in fire intensity and severity than to timing of the burn relative to stage of plant growth. ?? 2007 NRC.

Reactive Nitrogen Multiphase Chemistry and Chlorine Activation on Authentic Biomass Burning Aerosol

NASA Astrophysics Data System (ADS)

Goldberger, Lexie

Biomass burning is both a major source of particulate matter and reactive nitrogen oxide radicals, yet the rate and products of the multiphase chemistry between the two has not been well studied. Nitryl chloride (ClNO2), formed by the multiphase reaction of dinitrogen pentoxide (N2O 5) on chloride-containing particles, is known to occur in polluted marine environments where it contributes significantly to the oxidant budget. Since the observation of ClNO2 levels in a moderately polluted region far from the coast, there has been motivation to determine the source of particulate chloride, postulated as the limiting ingredient to ClNO2 formation. Using a smog chamber reactor at Carnegie Mellon University coupled to a biomass combustion chamber with controlled particle and gas injection, we simulated the nocturnal evolution of N2O5 in biomass burning plumes mixed with ozone. A range of authentic fuel types, including saw grass, cut grass, and white European birch were burned in the combustion chamber and a portion of the smoke plume was then mixed into the 12 m3 chamber, where it was exposed to 70-150 ppb of ozone and relative humidity ranging from 0-60% in the dark. Gaseous N 2O5, nitric acid (HNO3), ClNO 2, Cl2, and HCl were monitored using a high resolution time of flight iodide adduct chemical ionization mass spectrometer, and particle size distributions and composition were monitored continuously with an SMPS and a Soot-Particle Aerosol Mass Spectrometer among other instruments. With chemical mechanism modeling I attempt to abstract N2O 5 uptake coefficients as well as molar yields of ClNO2 and report correlated changes in Cl2 and HCl. I analyze dependences on combustion fuel type. These results suggest a potentially important impact of chlorine atom initiated oxidation in biomass burning plumes. The uptake of N2O5 and yields of ClNO2, Cl2, and HCl determined from this study will allow for more robust parameterizations of these compounds in atmospheric models.

Polar and non-polar organic aerosols from large-scale agricultural-waste burning emissions in Northern India: Implications to organic mass-to-organic carbon ratio.

PubMed

Rajput, Prashant; Sarin, M M

2014-05-01

This study focuses on characteristics of organic aerosols (polar and non-polar) and total organic mass-to-organic carbon ratio (OM/OC) from post-harvest agricultural-waste (paddy- and wheat-residue) burning emissions in Northern India. Aerosol samples from an upwind location (Patiala: 30.2°N, 76.3°E) in the Indo-Gangetic Plain were analyzed for non-polar and polar fractions of organic carbon (OC1 and OC2) and their respective mass (OM1 and OM2). On average, polar organic aerosols (OM2) contribute nearly 85% of the total organic mass (OM) from the paddy- and wheat-residue burning emissions. The water-soluble-OC (WSOC) to OC2 ratio, within the analytical uncertainty, is close to 1 from both paddy- and wheat-residue burning emissions. However, temporal variability and relatively low WSOC/OC2 ratio (Av: 0.67±0.06) is attributed to high moisture content and poor combustion efficiency during paddy-residue burning, indicating significant contribution (∼30%) of aromatic carbon to OC2. The OM/OC ratio for non-polar (OM1/OC1∼1.2) and polar organic aerosols (OM2/OC2∼2.2), hitherto unknown for open agricultural-waste burning emissions, is documented in this study. The total OM/OC ratio is nearly identical, 1.9±0.2 and 1.8±0.2, from paddy- and wheat-residue burning emissions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Fuel consumption and fire characteristics during understory burning in a mixed white pine-hardwood stand in the Southern Appalachians.

Treesearch

Barton D. Clinton; James M. Vose; Wayne T. Swank; Erik C. Berg; David L. Loftis

1998-01-01

We characterized tire behavior and fuel consumption resulting from an understory prescribed burn in a mixed eastern white pine-hardwood stand in the Southern Appalachians. These stands were used for the treatment. Flame lengths, ranging from 0.3 to 1.5 meters (m) for backing fires and from 1.2 to 4.5 m for head fires, reached maximum heights where evergreen understory...

Particle and Gas Emissions from an In Situ Burn of Crude Oil on the Ocean.

PubMed

Hobbs, John L Ross Ronald J Ferek And Peter V

1996-03-01

Burning is a very effective way of removing oil spills from the ocean; the tradeoff is the potential for significant air pollution. Airborne measurements are described for particles and gases from two test burns of crude oil offshore of St. Johns, Newfoundland during the Newfoundland Offshore Burn Experiment (NOBE). The smoke plumes from the burns initially rose 200-400 m into the air and then continued to rise and disperse laterally downwind. The concentrations of accumulation-mode particles in the smoke were ~45,000 cm -3 at 1.5 km from the fires, and they remained as high as ~4,000 cm -3 after an hour or more of travel time downwind. Total particle mass loadings in the plumes were over 1000 µg m -3 near the fires, but decreased to ~100 µg m -3 at 25 km downwind. For each kilogram of fuel consumed, ~770 g of carbon was released in the form of CO2, ~13 g of carbon as CO, -5 g as volatile organic compounds (VOCs), and -87 g as particles with diameters <3.5 µm, of which ~66 g was elemental carbon and ~7 g condensed organic carbon. Also, ~3 g of SO2 was released per kilogram of fuel burned. A relatively low combustion efficiency was indicated by the average molar ratio of the concentration of CO to excess CO2 of 0.017. The molar ratio of NOX to excess CO2 typically varied from 0.3 x 10 -3 to 0.4 x 10 -3 , implying little fixation of atmospheric nitrogen and low concentrations of NOX. For comparison, the total smoke particle production rate in the NOBE burns was about the same as that for a nineacre slash burn.

Mapping burned areas and burn severity patterns across the Mediterranean region

NASA Astrophysics Data System (ADS)

Kalogeropoulos, Christos; Amatulli, Giuseppe; Kempeneers, Pieter; Sedano, Fernando; San Miguel-Ayanz, Jesus; Camia, Andrea

2010-05-01

The Mediterranean region is highly susceptible to wildfires. On average, about 60,000 fires take place in this region every year, burning on average half a million hectares of forests and natural vegetation. Wildfires cause environmental degradation and affect the lives of thousands of people in the region. In order to minimize the consequences of these catastrophic events, fire managers and national authorities need to have in their disposal accurate and updated spatial information concerning the size of the burned area as well as the burn severity patterns. Mapping burned areas and burn severity patterns is necessary to effectively support the decision-making process in what concerns strategic (long-term) planning with the definition of post-fire actions at European and national scales. Although a comprehensive archive of burnt areas exists at the European Forest Fire Information System, the analysis of the severity of the areas affected by forest fires in the region is not yet available. Fire severity is influenced by many variables, including fuel type, topography and meteorological conditions before and during the fire. The analysis of fire severity is essential to determine the socio-economic impact of forest fires, to assess fire impacts, and to determine the need of post-fire rehabilitation measures. Moreover, fire severity is linked to forest fire emissions and determines the rate of recovery of the vegetation after the fire. Satellite imagery can give important insights about the conditions of the live fuel moisture content and can be used to assess changes on vegetation structure and vitality after forest fires. Fire events occurred in Greece, Portugal and Spain during the fire season of 2009 were recorded and analyzed in a GIS environment. The Normalized Difference Vegetation Index (NDVI), the Enhanced Vegetation Index (EVI) and the Normalized Burn Ratio (NBR) were calculated from 8-days composites MODIS/TERRA imagery from March to October 2009. In

Characterizing hand-piled fuels

Treesearch

Clinton S. Wright; Paige C. Eagle; Cameron S. Balog

2010-01-01

Land managers throughout the West pile and burn surface fuels to mitigate fire hazard in dry forests. Whereas piling was historically conducted with heavy machinery following commercial harvesting operations, land managers are increasingly prescribing the use of hand piling and burning to treat surface fuels created by thinning and brush cutting. An estimate of the...

Intense atmospheric pollution modifies weather: a~case of mixed biomass burning with fossil fuel combustion pollution in the eastern China

NASA Astrophysics Data System (ADS)

Ding, A. J.; Fu, C. B.; Yang, X. Q.; Sun, J. N.; Petäjä, T.; Kerminen, V.-M.; Wang, T.; Xie, Y. N.; Herrmann, E.; Zheng, L. F.; Nie, W.; Wei, X. L.; Kulmala, M.

2013-06-01

The influence of air pollutants, particularly aerosols, on regional and global climate is widely investigated, but only a very limited number of studies reports their impacts on everyday weather. In this work, we present for the first time direct (observational) evidence of a clear effect how a mixed atmospheric pollution changes the weather with a substantial modification in air temperature and rainfall. By using comprehensive measurements in Nanjing, China, we found that mixed agricultural burning plumes with fossil fuel combustion pollution resulted in a decrease of solar radiation by more than 70%, of sensible heat flux over 85%, a temperature drop by almost 10 K, and a change of rainfall during daytime and nighttime. Our results show clear air pollution - weather interactions, and quantify how air pollution affects weather with the influence of air pollution-boundary layer dynamics and aerosol-radiation-cloudy feedbacks. This study highlights a cross-disciplinary needs to study the environmental, weather and climate impact of the mixed biomass burning and fossil fuel combustion sources in the East China.

NASA Alternative Aviation Fuel Research

NASA Astrophysics Data System (ADS)

Anderson, B. E.; Beyersdorf, A. J.; Thornhill, K. L., II; Moore, R.; Shook, M.; Winstead, E.; Ziemba, L. D.; Crumeyrolle, S.

2015-12-01

We present an overview of research conducted by NASA Aeronautics Research Mission Directorate to evaluate the performance and emissions of "drop-in" alternative jet fuels, highlighting experiment design and results from the Alternative Aviation Fuel Experiments (AAFEX-I & -II) and Alternative Fuel-Effects on Contrails and Cruise Emissions flight series (ACCESS-I & II). These projects included almost 100 hours of sampling exhaust emissions from the NASA DC-8 aircraft in both ground and airborne operation and at idle to takeoff thrust settings. Tested fuels included Fischer-Tropsch (FT) synthetic kerosenes manufactured from coal and natural-gas feedstocks; Hydro-treated Esters and Fatty-Acids (HEFA) fuels made from beef-tallow and camelina-plant oil; and 50:50 blends of these alternative fuels with Jet A. Experiments were also conducted with FT and Jet A fuels doped with tetrahydrothiophene to examine the effects of fuel sulfur on volatile aerosol and contrail formation and microphysical properties. Results indicate that although the absence of aromatic compounds in the alternative fuels caused DC-8 fuel-system leaks, the fuels did not compromise engine performance or combustion efficiency. And whereas the alternative fuels produced only slightly different gas-phase emissions, dramatic reductions in non-volatile particulate matter (nvPM) emissions were observed when burning the pure alternative fuels, particularly at low thrust settings where particle number and mass emissions were an order of magnitude lower than measured from standard jet fuel combustion; 50:50 blends of Jet A and alternative fuels typically reduced nvPM emissions by ~50% across all thrust settings. Alternative fuels with the highest hydrogen content produced the greatest nvPM reductions. For Jet A and fuel blends, nvPM emissions were positively correlated with fuel aromatic and naphthalene content. Fuel sulfur content regulated nucleation mode aerosol number and mass concentrations within aging

The impact of oil burning on kraft recovery furnace SO sub 2 emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Someshwar, A.V.; Pinkerton, J.E.; Caron, A.L.

1991-04-01

Auxiliary fossil fuel, either natural gas or fuel oil, is burned in kraft recovery furnaces during furnace startups and shutdowns, furnace upsets, and periods of substantially reduced rates of black liquor firing. The efficiency of sulfur capture and retention during normal operation of a kraft recovery furnace is inherently high. Consequently, not all the SO{sub 2} from occasional burning of sulfur-containing fuel oil in the furnace would be expected to end up in the stack gases. However, the extent to which such SO{sub 2} is captured by the alkali fume generation processes has not been well documented. In this paper,more » the authors examines the impact that burning oil in kraft recovery furnaces has on the SO{sub 2} emissions. The work included analyses of long-term SO{sub 2} data from a continuous emission monitoring system (CEMS) obtained for four furnaces that burned medium sulfur fuel oil as auxiliary fuel. It also included tests conducted on four furnaces in which varying amounts of oil were co-fired with black liquor.« less

Powder Metallurgy of Uranium Alloy Fuels for TRU-Burning Reactors Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDeavitt, Sean M

2011-04-29

Helmreich outlining the beginning of the materials processing setup. Also included within this section is a thesis proposal by Jeff Hausaman. Appendix C contains the public papers and presentations introduced at the 2010 American Nuclear Society Winter Meeting. Appendix A—MSNE theses of David Garnetti and Grant Helmreich and proposal by Jeff Hausaman A.1 December 2009 Thesis by David Garnetti entitled “Uranium Powder Production Via Hydride Formation and Alpha Phase Sintering of Uranium and Uranium-Zirconium Alloys for Advanced Nuclear Fuel Applications” A.2 September 2009 Presentation by David Garnetti (same title as document in Appendix B.1) A.3 December 2010 Thesis by Grant Helmreich entitled “Characterization of Alpha-Phase Sintering of Uranium and Uranium-Zirconium Alloys for Advanced Nuclear Fuel Applications” A.4 October 2010 Presentation by Grant Helmreich (same title as document in Appendix B.3) A.5 Thesis Proposal by Jeffrey Hausaman entitled “Hot Extrusion of Alpha Phase Uranium-Zirconium Alloys for TRU Burning Fast Reactors” Appendix B—External presentations introduced at the 2010 ANS Winter Meeting B.1 J.S. Hausaman, D.J. Garnetti, and S.M. McDeavitt, “Powder Metallurgy of Alpha Phase Uranium Alloys for TRU Burning Fast Reactors,” Proceedings of 2010 ANS Winter Meeting, Las Vegas, Nevada, USA, November 7-10, 2010 B.2 PowerPoint Presentation Slides from C.1 B.3 G.W. Helmreich, W.J. Sames, D.J. Garnetti, and S.M. McDeavitt, “Uranium Powder Production Using a Hydride-Dehydride Process,” Proceedings of 2010 ANS Winter Meeting, Las Vegas, Nevada, USA, November 7-10, 2010 B.4. PowerPoint Presentation Slides from C.3 B.5 Poster Presentation from C.3 Appendix C—Fuel cycle research and development undergraduate materials and poster presentation C.1 Poster entitled “Characterization of Alpha-Phase Sintering of Uranium and Uranium-Zirconium Alloys” presented at the Fuel Cycle Technologies Program Annual Meeting C.2 April 2011 Honors

Macro-particle charcoal C content following prescribed burning in a mixed-conifer forest, Sierra Nevada, California.

PubMed

Wiechmann, Morgan L; Hurteau, Matthew D; Kaye, Jason P; Miesel, Jessica R

2015-01-01

Fire suppression and changing climate have resulted in increased large wildfire frequency and severity in the western United States, causing carbon cycle impacts. Forest thinning and prescribed burning reduce high-severity fire risk, but require removal of biomass and emissions of carbon from burning. During each fire a fraction of the burning vegetation and soil organic matter is converted into charcoal, a relatively stable carbon form. We sought to quantify the effects of pre-fire fuel load and type on charcoal carbon produced by biomass combusted in a prescribed burn under different thinning treatments and to identify more easily measured predictors of charcoal carbon mass in a historically frequent-fire mixed-conifer forest. We hypothesized that charcoal carbon produced from coarse woody debris (CWD) during prescribed burning would be greater than that produced from fine woody debris (FWD). We visually quantified post-treatment charcoal carbon content in the O-horizon and the A-horizon beneath CWD (> 30 cm diameter) and up to 60 cm from CWD that was present prior to treatment. We found no difference in the size of charcoal carbon pools from CWD (treatment means ranged from 0.3-2.0 g m-2 of A-horizon and 0.0-1.7 g m-2 of O-horizon charcoal) and FWD (treatment means ranged from 0.2-1.7 g m-2 of A-horizon and 0.0-1.5 g m-2 of O-horizon charcoal). We also compared treatments and found that the burn-only, understory-thin and burn, and overstory-thin and burn treatments had significantly more charcoal carbon than the control. Charcoal carbon represented 0.29% of total ecosystem carbon. We found that char mass on CWD was an important predictor of charcoal carbon mass, but only explained 18-35% of the variation. Our results help improve our understanding of the effects forest restoration treatments have on ecosystem carbon by providing additional information about charcoal carbon content.

Macro-Particle Charcoal C Content following Prescribed Burning in a Mixed-Conifer Forest, Sierra Nevada, California

PubMed Central

Wiechmann, Morgan L.; Hurteau, Matthew D.; Kaye, Jason P.; Miesel, Jessica R.

2015-01-01

Fire suppression and changing climate have resulted in increased large wildfire frequency and severity in the western United States, causing carbon cycle impacts. Forest thinning and prescribed burning reduce high-severity fire risk, but require removal of biomass and emissions of carbon from burning. During each fire a fraction of the burning vegetation and soil organic matter is converted into charcoal, a relatively stable carbon form. We sought to quantify the effects of pre-fire fuel load and type on charcoal carbon produced by biomass combusted in a prescribed burn under different thinning treatments and to identify more easily measured predictors of charcoal carbon mass in a historically frequent-fire mixed-conifer forest. We hypothesized that charcoal carbon produced from coarse woody debris (CWD) during prescribed burning would be greater than that produced from fine woody debris (FWD). We visually quantified post-treatment charcoal carbon content in the O-horizon and the A-horizon beneath CWD (> 30 cm diameter) and up to 60 cm from CWD that was present prior to treatment. We found no difference in the size of charcoal carbon pools from CWD (treatment means ranged from 0.3–2.0 g m-2 of A-horizon and 0.0–1.7 g m-2 of O-horizon charcoal) and FWD (treatment means ranged from 0.2–1.7 g m-2 of A-horizon and 0.0–1.5 g m-2 of O-horizon charcoal). We also compared treatments and found that the burn-only, understory-thin and burn, and overstory-thin and burn treatments had significantly more charcoal carbon than the control. Charcoal carbon represented 0.29% of total ecosystem carbon. We found that char mass on CWD was an important predictor of charcoal carbon mass, but only explained 18–35% of the variation. Our results help improve our understanding of the effects forest restoration treatments have on ecosystem carbon by providing additional information about charcoal carbon content. PMID:26258533

The effect of azeotropism on combustion characteristics of blended fuel pool fire.

PubMed

Ding, Yanming; Wang, Changjian; Lu, Shouxiang

2014-04-30

The effect of azeotropism on combustion characteristics of blended fuel pool fire was experimentally studied in an open fire test space of State Key Laboratory of Fire Science. A 30 cm × 30 cm square pool filled with n-heptane and ethanol blended fuel was employed. Flame images, burning rate and temperature distribution were collected and recorded in the whole combustion process. Results show that azeotropism obviously dominates the combustion behavior of n-heptane/ethanol blended fuel pool fire. The combustion process after ignition exhibits four typical stages: initial development, azeotropic burning, single-component burning and decay stage. Azeotropism appears when temperature of fuel surface reaches azeotropic point and blended fuel burns at azeotropic ratio. Compared with individual pure fuel, the effect of azeotropism on main fire parameters, such as flame height, burning rate, flame puffing frequency and centerline temperature were analyzed. Burning rate and centerline temperature of blended fuel are higher than that of individual pure fuel respectively at azeotropic burning stage, and flame puffing frequency follows the empirical formula between Strouhal and Froude number for pure fuel. Copyright © 2014 Elsevier B.V. All rights reserved.

Piloted ignition of live forest fuels

Treesearch

S. McAllister; I. Grenfell; A. Hadlow; W. M. Jolly; M. Finney; J. Cohen

2012-01-01

The most unpredictable and uncontrollable wildfires are those that burn in the crowns of live vegetation. The fuels that feed these crown fires are mostly live, green foliage. Unfortunately, little is known about how live fuels combust. To understand how live fuels burn, piloted ignition experiments were performed with lodgepole pine and Douglas-fir. The thermal...

Impact of reformulated fuels on motor vehicle emissions

NASA Astrophysics Data System (ADS)

Kirchstetter, Thomas

Motor vehicles continue to be an important source of air pollution. Increased vehicle travel and degradation of emission control systems have offset some of the effects of increasingly stringent emission standards and use of control technologies. A relatively new air pollution control strategy is the reformulation of motor vehicle fuels, both gasoline and diesel, to make them cleaner- burning. Field experiments in a heavily traveled northern California roadway tunnel revealed that use of oxygenated gasoline reduced on-road emissions of carbon monoxide (CO) and volatile organic compounds (VOC) by 23 +/- 6% and 19 +/- 8%, respectively, while oxides of nitrogen (NOx) emissions were not significantly affected. The introduction of reformulated gasoline (RFG) in California led to large changes in gasoline composition including decreases in alkene, aromatic, benzene, and sulfur contents, and an increase in oxygen content. The combined effects of RFG and fleet turnover between summers 1994 and 1997 were decreases in on-road vehicle exhaust emissions of CO, non-methane VOC, and NOx by 31 +/- 5, 43 +/- 8, and 18 +/- 4%, respectively. Although it was difficult to separate the fleet turnover and RFG contributions to these changes, it was clear that the effect of RFG was greater for VOC than for NOx. The RFG effect on exhaust emissions of benzene was a 30-40% reduction. Use of RFG reduced the reactivity of liquid gasoline and gasoline headspace vapors by 23 and 19%, respectively. Increased use of methyl tert-butyl ether in gasoline led to increased concentrations of highly reactive formaldehyde and isobutene in vehicle exhaust. As a result, RFG reduced the reactivity of exhaust emissions by only about 5%. Per unit mass of fuel burned, heavy-duty diesel trucks emit about 25 times more fine particle mass and 15-20 times the number of fine particles compared to light-duty vehicles. Exhaust fine particle emissions from heavy-duty diesels contain more black carbon than particulate

Indoor air pollution from burning yak dung as a household fuel in Tibet

NASA Astrophysics Data System (ADS)

Xiao, Qingyang; Saikawa, Eri; Yokelson, Robert J.; Chen, Pengfei; Li, Chaoliu; Kang, Shichang

2015-02-01

Yak dung is widely used for cooking and heating in Tibet. We measured real-time concentrations of black carbon (BC) and fine particulate matter with an aerodynamic diameter of 2.5 μm or less (PM2.5) emitted by yak dung burning in six households with different living conditions and stove types in the Nam Co region, Tibet. We observed a much lower average BC/PM2.5 mass ratio (0.013, range 0.006-0.028) from dung combustion in this area than previously reported estimates, ranging between 0.05 and 0.11. Based on our measurements, estimated fuel use, and published emission factors of BC and PM2.5, about 0.4-1.7 Gg/year of BC is emitted by yak dung combustion in Tibet in addition to the previously estimated 0.70 Gg/year of BC for Tibetan residential sources. Our survey shows that most residents were aware of adverse health impacts of indoor yak dung combustion and approximately 2/3 of residents had already installed chimney stoves to mitigate indoor air pollution. However, our measurements reveal that, without adequate ventilation, installing a chimney may not ensure good indoor air quality. For instance, the 6-h average BC and PM2.5 concentrations in a stone house using a chimney stove were 24.5 and 873 μg/m3, respectively. We also observed a change in the BC/PM2.5 ratios before and after a snow event. The impact of dung moisture content on combustion efficiency and pollutant emissions needs further investigation.

Two-Dimensional Imaging of OH in a Lean Burning High Pressure Combustor

NASA Technical Reports Server (NTRS)

Locke, R. J.; Hicks, Y. R.; Anderson, R. C.; Ockunzzi, K. A.; North, G. L.

1995-01-01

Planar laser-induced fluorescence (PLIF) images of OH have been obtained from an optically accessible, lean burning high pressure combustor burning Jet-A fuel. These images were obtained using various laser excitation lines of the OH A (reverse arrow) X (1,0) band for several fuel injector configurations with pressures ranging from 1013 kPa (10 atm) to 1419 kPa (14 atm). Non-uniformities in the combusting flow, attributed to differences in fuel injector configuration, are revealed by these images. Contributions attributable to fluorescent aromatic hydrocarbons and complex fuel chemistries are also not evident.

Performance modeling of Deep Burn TRISO fuel using ZrC as a load-bearing layer and an oxygen getter

NASA Astrophysics Data System (ADS)

Wongsawaeng, Doonyapong

2010-01-01

The effects of design choices for the TRISO particle fuel were explored in order to determine their contribution to attaining high-burnup in Deep Burn modular helium reactor fuels containing transuranics from light water reactor spent fuel. The new design features were: (1) ZrC coating substituted for the SiC, allowing the fuel to survive higher accident temperatures; (2) pyrocarbon/SiC "alloy" substituted for the inner pyrocarbon coating to reduce layer failure and (3) pyrocarbon seal coat and thin ZrC oxygen getter coating on the kernel to eliminate CO. Fuel performance was evaluated using General Atomics Company's PISA code. The only acceptable design has a 200-μm kernel diameter coupled with at least 150-μm thick, 50% porosity buffer, a 15-μm ZrC getter over a 10-μm pyrocarbon seal coat on the kernel, an alloy inner pyrocarbon, and ZrC substituted for SiC. The code predicted that during a 1600 °C postulated accident at 70% FIMA, the ZrC failure probability is <10-4.

Spectroscopic analysis of seasonal changes in live fuel moisture content and leaf dry mass

Treesearch

Yi Qi; Philip E. Dennison; W. Matt Jolly; Rachael C. Kropp; Simon C. Brewer

2014-01-01

Live fuel moisture content (LFMC), the ratio of water mass to dry mass contained in live plant material, is an important fuel property for determining fire danger and for modeling fire behavior. Remote sensing estimation of LFMC often relies on an assumption of changing water and stable dry mass over time. Fundamental understanding of seasonal variation in plant water...

Laboratory measurements of emission factors of nonmethane volatile organic compounds from burning of Chinese crop residues

NASA Astrophysics Data System (ADS)

Inomata, Satoshi; Tanimoto, Hiroshi; Pan, Xiaole; Taketani, Fumikazu; Komazaki, Yuichi; Miyakawa, Takuma; Kanaya, Yugo; Wang, Zifa

2015-05-01

The emission factors (EFs) of nonmethane volatile organic compounds (NMVOCs) emitted during the burning of Chinese crop residue were investigated as a function of modified combustion efficiency in laboratory experiments. NMVOCs, including acetonitrile, aldehydes/ketones, furan, and aromatic hydrocarbons, were monitored by proton-transfer-reaction mass spectrometry. Rape plant was burned in dry conditions and wheat straw was burned in both wet and dry conditions to simulate the possible burning of damp crop residue in regions of high temperature and humidity. We compared the present data to field data reported by Kudo et al. (2014). Good agreement between field and laboratory data was obtained for aromatics under relatively more smoldering combustion of dry samples, but laboratory data were slightly overestimated compared to field data for oxygenated VOC (OVOC). When EFs from the burning of wet samples were investigated, the consistency between the field and laboratory data for OVOCs was stronger than for dry samples. This may be caused by residual moisture in crop residue that has been stockpiled in humid regions. Comparison of the wet laboratory data with field data suggests that Kudo et al. (2014) observed the biomass burning plumes under relatively more smoldering conditions in which approximately a few tens of percentages of burned fuel materials were wet.

Performance characterization of complex fuel port geometries for hybrid rocket fuel grains

NASA Astrophysics Data System (ADS)

Bath, Andrew

This research investigated the 3D printing and burning of fuel grains with complex geometry and the development of software capable of modeling and predicting the regression of a cross-section of these complex fuel grains. The software developed did predict the geometry to a fair degree of accuracy, especially when enhanced corner rounding was turned on. The model does have some drawbacks, notably being relatively slow, and does not perfectly predict the regression. If corner rounding is turned off, however, the model does become much faster; although less accurate, this method does still predict a relatively accurate resulting burn geometry, and is fast enough to be used for performance-tuning or genetic algorithms. In addition to the modeling method, preliminary investigations into the burning behavior of fuel grains with a helical flow path were performed. The helix fuel grains have a regression rate of nearly 3 times that of any other fuel grain geometry, primarily due to the enhancement of the friction coefficient between the flow and flow path.

Uniform-burning matrix burner

DOEpatents

Bohn, Mark S.; Anselmo, Mark

2001-01-01

Computer simulation was used in the development of an inward-burning, radial matrix gas burner and heat pipe heat exchanger. The burner and exchanger can be used to heat a Stirling engine on cloudy days when a solar dish, the normal source of heat, cannot be used. Geometrical requirements of the application forced the use of the inward burning approach, which presents difficulty in achieving a good flow distribution and air/fuel mixing. The present invention solved the problem by providing a plenum with just the right properties, which include good flow distribution and good air/fuel mixing with minimum residence time. CFD simulations were also used to help design the primary heat exchanger needed for this application which includes a plurality of pins emanating from the heat pipe. The system uses multiple inlet ports, an extended distance from the fuel inlet to the burner matrix, flow divider vanes, and a ring-shaped, porous grid to obtain a high-temperature uniform-heat radial burner. Ideal applications include dish/Stirling engines, steam reforming of hydrocarbons, glass working, and any process requiring high temperature heating of the outside surface of a cylindrical surface.

Fuel: Logs, sticks, needles, duff, and much more

Treesearch

Russell T. Graham; Theresa Benevidez Jain; Alan E. Harvey

2000-01-01

Fuels burned by either prescribed or wildfires are complex and important components of forested ecosystems. Fine fuels consisting of fallen limbs, twigs, and leaves of shrubs and trees are rich in nutrients. If these fuels are not immediately burned, nutrients can leach from these materials into the forest floor, especially if they overwinter. Larger fuels consisting...

Fossil fuel and biomass burning effect on climate - Heating or cooling?

NASA Technical Reports Server (NTRS)

Kaufman, Yoram J.; Fraser, Robert S.; Mahoney, Robert L.

1991-01-01

The basic theory of the effect of pollution on cloud microphysics and its global implications is applied to compare the relative effect of a small increase in the consumption rate of oil, coal, or biomass burning on cooling and heating of the atmosphere. The characteristics of and evidence for the SO2 induced cooling effect are reviewed. This perturbation analysis approach permits linearization, therefore simplifying the analysis and reducing the number of uncertain parameters. For biomass burning the analysis is restricted to burning associated with deforestation. Predictions of the effect of an increase in oil or coal burning show that within the present conditions the cooling effect from oil and coal burning may range from 0.4 to 8 times the heating effect.

Numerical study of external burning flowfields

NASA Technical Reports Server (NTRS)

Bittner, Robert D.; Mcclinton, Charles R.

1991-01-01

This paper demonstrates the successful application of CFD to modeling an external burning flowfield. The study used the 2D, 3D, and PNS versions of the SPARK code. Various grids, boundary conditions, and ignition methodologies have been employed. Flameholding was achieved through the use of a subsonic outflow condition and a hot block located behind the step to ignite the fuel. Since the resulting burning produces a large subsonic region downstream of the cowl, this entire surface can be pressurized to the level of the back pressure. An evaluation of interactions between the ramjet exhaust and the external burning products demonstrate the complexity of this design issue. Ths code is now capable of evaluating the external burning effectiveness for flight vehicles using simple injector schemes, and the methodology can be readily applied to other external burning designs.

Particulate matter chemical component concentrations and sources in settings of household solid fuel use.

PubMed

Secrest, M H; Schauer, J J; Carter, E M; Baumgartner, J

2017-11-01

Particulate matter (PM) air pollution derives from combustion and non-combustion sources and consists of various chemical species that may differentially impact human health and climate. Previous reviews of PM chemical component concentrations and sources focus on high-income urban settings, which likely differ from the low- and middle-income settings where solid fuel (ie, coal, biomass) is commonly burned for cooking and heating. We aimed to summarize the concentrations of PM chemical components and their contributing sources in settings where solid fuel is burned. We searched the literature for studies that reported PM component concentrations from homes, personal exposures, and direct stove emissions under uncontrolled, real-world conditions. We calculated weighted mean daily concentrations for select PM components and compared sources of PM determined by source apportionment. Our search criteria yielded 48 studies conducted in 12 countries. Weighted mean daily cooking area concentrations of elemental carbon, organic carbon, and benzo(a)pyrene were 18.8 μg m -3 , 74.0 μg m -3 , and 155 ng m -3 , respectively. Solid fuel combustion explained 29%-48% of principal component/factor analysis variance and 41%-87% of PM mass determined by positive matrix factorization. Multiple indoor and outdoor sources impacted PM concentrations and composition in these settings, including solid fuel burning, mobile emissions, dust, and solid waste burning. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Global Partitioning of NOx Sources Using Satellite Observations: Relative Roles of Fossil Fuel Combustion, Biomass Burning and Soil Emissions

NASA Technical Reports Server (NTRS)

Jaegle, Lyatt; Steinberger, Linda; Martin, Randall V.; Chance, Kelly

2005-01-01

This document contains the following abstract for the paper "Global partitioning of NOx sources using satellite observations: Relative roles of fossil fuel combustion, biomass burning and soil emissions." Satellite observations have been used to provide important new information about emissions of nitrogen oxides. Nitrogen oxides (NOx) are significant in atmospheric chemistry, having a role in ozone air pollution, acid deposition and climate change. We know that human activities have led to a three- to six-fold increase in NOx emissions since pre-industrial times, and that there are three main surface sources of NOx: fuel combustion, large-scale fires, and microbial soil processes. How each of these sources contributes to the total NOx emissions is subject to some doubt, however. The problem is that current NOx emission inventories rely on bottom-up approaches, compiling large quantities of statistical information from diverse sources such as fuel and land use, agricultural data, and estimates of burned areas. This results in inherently large uncertainties. To overcome this, Lyatt Jaegle and colleagues from the University of Washington, USA, used new satellite observations from the Global Ozone Monitoring Experiment (GOME) instrument. As the spatial and seasonal distribution of each of the sources of NOx can be clearly mapped from space, the team could provide independent topdown constraints on the individual strengths of NOx sources, and thus help resolve discrepancies in existing inventories. Jaegle's analysis of the satellite observations, presented at the recent Faraday Discussion on "Atmospheric Chemistry", shows that fuel combustion dominates emissions at northern mid-latitudes, while fires are a significant source in the Tropics. Additionally, she discovered a larger than expected role for soil emissions, especially over agricultural regions with heavy fertilizer use. Additional information is included in the original extended abstract.

OBSTRUCTIVE LUNG DISEASE AND EXPOSURE TO BURNING BIOMASS FUEL IN THE INDOOR ENVIRONMENT.

PubMed

Diette, Gregory B; Accinelli, Roberto A; Balmes, John R; Buist, A Sonia; Checkley, William; Garbe, Paul; Hansel, Nadia N; Kapil, Vikas; Gordon, Stephen; Lagat, David K; Yip, Fuyuen; Mortimer, Kevin; Perez-Padilla, Rogelio; Roth, Christa; Schwaninger, Julie M; Punturieri, Antonello; Kiley, James

2012-09-01

It is estimated that up to half of the world's population burns biomass fuel (wood, crop residues, animal dung and coal) for indoor uses such as cooking, lighting and heating. As a result, a large proportion of women and children are exposed to high levels of household air pollution (HAP). The short and long term effects of these exposures on the respiratory health of this population are not clearly understood. On May 9-11, 2011 NIH held an international workshop on the "Health Burden of Indoor Air Pollution on Women and Children," in Arlington, VA. To gather information on the knowledge base on this topic and identify research gaps, ahead of the meeting we conducted a literature search using PubMed to identify publications that related to HAP, asthma, and chronic obstructive pulmonary disease (COPD). Abstracts were all analyzed and we report on those considered by the respiratory sub study group at the meeting to be most relevant to the field. Many of the studies published are symptom-based studies (as opposed to objective measures of lung function or clinical examination etc.) and measurement of HAP was not done. Many found some association between indoor exposures to biomass smoke as assessed by stove type (e.g., open fire vs. liquid propane gas) and respiratory symptoms such as wheeze and cough. Among the studies that examined objective measures (e.g. spirometry) as a health outcome, the data supporting an association between biomass smoke exposure and COPD in adult women are fairly robust, but the findings for asthma are mixed. If an association was observed between the exposures and lung function, most data seemed to demonstrate mild to moderate reductions in lung function, the pathophysiological mechanisms of which need to be investigated. In the end, the group identified a series of scientific gaps and opportunities for research that need to be addressed to better understand the respiratory effects of exposure to indoor burning of the different forms of

OBSTRUCTIVE LUNG DISEASE AND EXPOSURE TO BURNING BIOMASS FUEL IN THE INDOOR ENVIRONMENT

PubMed Central

Diette, Gregory B.; Accinelli, Roberto A.; Balmes, John R.; Buist, A. Sonia; Checkley, William; Garbe, Paul; Hansel, Nadia N.; Kapil, Vikas; Gordon, Stephen; Lagat, David K.; Yip, Fuyuen; Mortimer, Kevin; Perez-Padilla, Rogelio; Roth, Christa; Schwaninger, Julie M.; Punturieri, Antonello; Kiley, James

2012-01-01

It is estimated that up to half of the world’s population burns biomass fuel (wood, crop residues, animal dung and coal) for indoor uses such as cooking, lighting and heating. As a result, a large proportion of women and children are exposed to high levels of household air pollution (HAP). The short and long term effects of these exposures on the respiratory health of this population are not clearly understood. On May 9–11, 2011 NIH held an international workshop on the "Health Burden of Indoor Air Pollution on Women and Children," in Arlington, VA. To gather information on the knowledge base on this topic and identify research gaps, ahead of the meeting we conducted a literature search using PubMed to identify publications that related to HAP, asthma, and chronic obstructive pulmonary disease (COPD). Abstracts were all analyzed and we report on those considered by the respiratory sub study group at the meeting to be most relevant to the field. Many of the studies published are symptom-based studies (as opposed to objective measures of lung function or clinical examination etc.) and measurement of HAP was not done. Many found some association between indoor exposures to biomass smoke as assessed by stove type (e.g., open fire vs. liquid propane gas) and respiratory symptoms such as wheeze and cough. Among the studies that examined objective measures (e.g. spirometry) as a health outcome, the data supporting an association between biomass smoke exposure and COPD in adult women are fairly robust, but the findings for asthma are mixed. If an association was observed between the exposures and lung function, most data seemed to demonstrate mild to moderate reductions in lung function, the pathophysiological mechanisms of which need to be investigated. In the end, the group identified a series of scientific gaps and opportunities for research that need to be addressed to better understand the respiratory effects of exposure to indoor burning of the different forms of

Long-range transport biomass burning emissions to the Himalayas: insights from high-resolution aerosol mass spectrometer

NASA Astrophysics Data System (ADS)

Xu, J.; Zhang, X.; Liu, Y.; Shichang, K.; Ma, Y.

2017-12-01

An intensive measurement was conducted at a remote, background, and high-altitude site (Qomolangma station, QOMS, 4276 m a.s.l.) in the northern Himalayas, using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) along with other collocated instruments. The field measurement was performed from April 12 to May 12, 2016 to chemically characterize high time-resolved submicron particulate matter (PM1) and obtain the influence of biomass burning emissions to the Himalayas, frequently transported from south Asia during pre-monsoon season. Two high aerosol loading periods were observed during the study. Overall, the average (± 1σ) PM1 mass concentration was 4.44 (± 4.54) µg m-3 for the entire study, comparable with those observed at other remote sites worldwide. Organic aerosols (OA) was the dominant PM1 species (accounting for 54.3% of total PM1 mass on average) and its contribution increased with the increase of total PM1 mass loading. The average size distributions of PM1 species all peaked at an overlapping accumulation mode ( 500 nm), suggesting that aerosol particles were internally well-mixed and aged during long-range transportations. Positive matrix factorization (PMF) analysis on the high-resolution organic mass spectra identified three distinct OA factors, including a biomass burning related OA (BBOA, 43.7%) and two oxygenated OA (Local-OOA and LRT-OOA; 13.9% and 42.4%) represented sources from local emissions and long-range transportations, respectively. Two polluted air mass origins (generally from the west and southwest of QOMS) and two polluted episodes with enhanced PM1 mass loadings and elevated BBOA contributions were observed, respectively, suggesting the important sources of wildfires from south Asia. One of polluted aerosol plumes was investigated in detail to illustrate the evolution of aerosol characteristics at QOMS driving by different impacts of wildfires, air mass origins, meteorological conditions and

Molecular composition of particulate matter emissions from dung and brushwood burning household cookstoves in Haryana, India

NASA Astrophysics Data System (ADS)

Fleming, Lauren T.; Lin, Peng; Laskin, Alexander; Laskin, Julia; Weltman, Robert; Edwards, Rufus D.; Arora, Narendra K.; Yadav, Ankit; Meinardi, Simone; Blake, Donald R.; Pillarisetti, Ajay; Smith, Kirk R.; Nizkorodov, Sergey A.

2018-02-01

Emissions of airborne particles from biomass burning are a significant source of black carbon (BC) and brown carbon (BrC) in rural areas of developing countries where biomass is the predominant energy source for cooking and heating. This study explores the molecular composition of organic aerosols from household cooking emissions with a focus on identifying fuel-specific compounds and BrC chromophores. Traditional meals were prepared by a local cook with dung and brushwood-fueled cookstoves in a village in Palwal district, Haryana, India. Cooking was done in a village kitchen while controlling for variables including stove type, fuel moisture, and meal. Fine particulate matter (PM2.5) emissions were collected on filters, and then analyzed via nanospray desorption electrospray ionization-high-resolution mass spectrometry (nano-DESI-HRMS) and high-performance liquid chromatography-photodiode array-high-resolution mass spectrometry (HPLC-PDA-HRMS) techniques. The nano-DESI-HRMS analysis provided an inventory of numerous compounds present in the particle phase. Although several compounds observed in this study have been previously characterized using gas chromatography methods a majority of the species in the nano-DESI spectra were newly observed biomass burning compounds. Both the stove (chulha or angithi) and the fuel (brushwood or dung) affected the composition of organic aerosols. The geometric mean of the PM2.5 emission factor and the observed molecular complexity increased in the following order: brushwood-chulha (7.3 ± 1.8 g kg-1 dry fuel, 93 compounds), dung-chulha (21.1 ± 4.2 g kg-1 dry fuel, 212 compounds), and dung-angithi (29.8 ± 11.5 g kg-1 dry fuel, 262 compounds). The mass-normalized absorption coefficient (MACbulk) for the organic-solvent extractable material for brushwood PM2.5 was 3.7 ± 1.5 and 1.9 ± 0.8 m2 g-1 at 360 and 405 nm, respectively, which was approximately a factor of two higher than that for dung PM2.5. The HPLC-PDA-HRMS analysis

Fuel and Combustor Concerns for Future Commercial Combustors

NASA Technical Reports Server (NTRS)

Chang, Clarence T.

2017-01-01

Civil aircraft combustor designs will move from rich-burn to lean-burn due to the latter's advantage in low NOx and nvPM emissions. However, the operating range of lean-burn is narrower, requiring premium mixing performance from the fuel injectors. As the OPR increases, the corresponding combustor inlet temperature increase can benefit greatly with fuel composition improvements. Hydro-treatment can improve coking resistance, allowing finer fuel injection orifices to speed up mixing. Selective cetane number control across the fuel carbon-number distribution may allow delayed ignition at high power while maintaining low-power ignition characteristics.

Comparative study on direct burning of oil shale and coal

NASA Astrophysics Data System (ADS)

Hammad, Ahmad; Al Asfar, Jamil

2017-07-01

A comparative study of the direct burning processes of oil shale and coal in a circulating fluidized bed (CFB) was done in this study using ANSYS Fluent software to solve numerically the governing equations of continuity, momentum, energy and mass diffusion using finite volume method. The model was built based on an existing experimental combustion burner unit. The model was validated by comparing the theoretical results of oil shale with proved experimental results from the combustion unit. It was found that the temperature contours of the combustion process showed that the adiabatic flame temperature was 1080 K for oil shale compared with 2260 K for coal, while the obtained experimental results of temperatures at various locations of burner during the direct burning of oil shale showed that the maximum temperature reached 962 K for oil shale. These results were used in economic and environmental analysis which show that oil shale may be used as alternative fuel for coal in cement industry in Jordan.

Helicopter fuel burn modeling in AEDT.

DOT National Transportation Integrated Search

2011-08-01

This report documents work done to enhance helicopter fuel consumption modeling in the Federal Aviation : Administrations Aviation Environmental Design Tool (AEDT). Fuel consumption and flight performance data : were collected from helicopter flig...

Chemical composition of wildland and agricultural biomass burning particles measured downwind during the BBOP study

NASA Astrophysics Data System (ADS)

Onasch, T. B.; Shilling, J. E.; Wormhoudt, J.; Sedlacek, A. J., III; Fortner, E.; Pekour, M. S.; Chand, D.; Zhou, S.; Collier, S.; Zhang, Q.; Kleinman, L. I.; Lewis, E. R.; Yokelson, R. J.; Adachi, K.; Buseck, P. R.; Freedman, A.; Williams, L. R.

2017-12-01

The Biomass Burning Observation Project (BBOP), a Department of Energy (DOE) sponsored study, measured emissions from wildland fires in the Pacific Northwest and agricultural burns in the Central Southeastern US from the DOE Gulfstream-1 airborne platform over a four month period in 2013. Rapid physical, chemical and optical changes in biomass burning particles were measured downwind (< 3 hours temporally) from wildland fires. The chemical composition of the particulate emissions was characterized using an Aerodyne Soot Particle Aerosol Mass Spectrometer (SP-AMS) and a Single Particle Soot Photometer (SP2) and the measurement results will be presented in the context of the fire location, combustion conditions, and optical property measurements, including extinction and single scattering albedos. The SP-AMS was operated with both laser and resistively heated tungsten vaporizers, alternating between laser on and off. With the laser vaporizer off, the instrument operated as a standard high resolution AMS. Under these sampling conditions, the non-refractory chemical composition, including the level of oxidation (i.e., O:C, H:C, and organic mass/organic carbon ratios, OM:OC), of the biomass burning particles was characterized as a function of the fuel type burned, modified combustion efficiency, and degree of oxidation during downwind transport. With the laser vaporizer on, the SP-AMS was also sensitive to the refractory black carbon (rBC) content, in addition to the non-refractory components. The chemical measurements will be correlated with simultaneous optical measurements. We will also present preliminary results from laboratory studies on tar balls and SP-AMS OA quantification while operating with both laser and tungsten vaporizers.

Global Inventory of Gas Geochemistry Data from Fossil Fuel, Microbial and Burning Sources, version 2017

NASA Astrophysics Data System (ADS)

Sherwood, Owen A.; Schwietzke, Stefan; Arling, Victoria A.; Etiope, Giuseppe

2017-08-01

The concentration of atmospheric methane (CH4) has more than doubled over the industrial era. To help constrain global and regional CH4 budgets, inverse (top-down) models incorporate data on the concentration and stable carbon (δ13C) and hydrogen (δ2H) isotopic ratios of atmospheric CH4. These models depend on accurate δ13C and δ2H end-member source signatures for each of the main emissions categories. Compared with meticulous measurement and calibration of isotopic CH4 in the atmosphere, there has been relatively less effort to characterize globally representative isotopic source signatures, particularly for fossil fuel sources. Most global CH4 budget models have so far relied on outdated source signature values derived from globally nonrepresentative data. To correct this deficiency, we present a comprehensive, globally representative end-member database of the δ13C and δ2H of CH4 from fossil fuel (conventional natural gas, shale gas, and coal), modern microbial (wetlands, rice paddies, ruminants, termites, and landfills and/or waste) and biomass burning sources. Gas molecular compositional data for fossil fuel categories are also included with the database. The database comprises 10 706 samples (8734 fossil fuel, 1972 non-fossil) from 190 published references. Mean (unweighted) δ13C signatures for fossil fuel CH4 are significantly lighter than values commonly used in CH4 budget models, thus highlighting potential underestimation of fossil fuel CH4 emissions in previous CH4 budget models. This living database will be updated every 2-3 years to provide the atmospheric modeling community with the most complete CH4 source signature data possible. Database digital object identifier (DOI): https://doi.org/10.15138/G3201T.

Fuel burn modeling of turboprop aircraft.

DOT National Transportation Integrated Search

2011-08-01

This report documents work done to enhance turbo-propeller aircraft fuel consumption modeling in the Federal Aviation Administrations Aviation Environmental Design Tool (AEDT). Fuel consumption and flight performance data were collected from aircr...

Burn hazards of the deployed environment in wartime: epidemiology of noncombat burns from ongoing United States military operations.

PubMed

Kauvar, David S; Wade, Charles E; Baer, David G

2009-10-01

Service in the deployed military environment carries risks for accidental (noncombat-related) burns. Examining these risks can assist in the development of military burn prevention measures. This study endeavored to examine noncombat burn epidemiology in the context of similar civilian data. We performed a retrospective cohort study of consecutive casualties evacuated from operational military theaters in Iraq and Afghanistan to the sole tertiary military burn center in the US. Military data were compared with database samples of the US population from the American Burn Association and the Centers for Disease Control and Prevention. The main causes of the 180 noncombat burns seen from March 2003 to June 2008 were waste burning, fuel mishaps, and unintentional ordinance detonations. Overall prevalence of noncombat burns was 19.5 burns/100,000 person-years lived. If causes specific to military operations are removed, military prevalence was 13.0/100,000. More than one-third of noncombat burns occurred in the first year of the study; a period of stability followed. A similar US population had an accidental burn prevalence of 7.1/100,000 from 2003 to 2007. Burn size, presence of inhalation injury, and burn center mortality were not different from those in a similar civilian cohort. Deployed service members have a greater risk of unintentional burns than a similar civilian cohort does. This is in part because of the specific dangers of military activities. More attention to deployed military burn prevention is needed, especially early in combat support operations.

Cyclic variations of fuel-droplet distribution during the early intake stroke of a lean-burn stratified-charge spark-ignition engine

NASA Astrophysics Data System (ADS)

Aleiferis, P. G.; Hardalupas, Y.; Taylor, A. M. K. P.; Ishii, K.; Urata, Y.

2005-11-01

Lean-burn spark-ignition engines exhibit higher efficiency and lower specific emissions in comparison with stoichiometrically charged engines. However, as the air-to-fuel (A/F) ratio of the mixture is made leaner than stoichiometric, cycle-by-cycle variations in the early stages of in-cylinder combustion, and subsequent indicated mean effective pressure (IMEP), become more pronounced and limit the range of lean-burn operation. Viable lean-burn engines promote charge stratification, the mixture near the spark plug being richer than the cylinder volume averaged value. Recent work has shown that cycle-by-cycle variations in the early stages of combustion in a stratified-charge engine can be associated with variations in both the local value of A/F ratio near the spark plug around ignition timing, as well as in the volume averaged value of the A/F ratio. The objective of the current work was to identify possible sources of such variability in A/F ratio by studying the in-cylinder field of fuel-droplet distribution during the early intake stroke. This field was visualised in an optical single-cylinder 4-valve pentroof-type spark-ignition engine by means of laser-sheet illumination in planes parallel to the cylinder head gasket 6 and 10 mm below the spark plug. The engine was run with port-injected isooctane at 1500 rpm with 30% volumetric efficiency and air-to-fuel ratio corresponding to both stoichiometric firing (A/F=15, Φ =1.0) and mixture strength close to the lean limit of stable operation (A/F=22, Φ =0.68). Images of Mie intensity scattered by the cloud of fuel droplets were acquired on a cycle-by-cycle basis. These were studied in order to establish possible correlations between the cyclic variations in size, location and scattered-light intensity of the cloud of droplets with the respective variations in IMEP. Because of the low level of Mie intensity scattered by the droplets and because of problems related to elastic scattering on the walls of the combustion

Effects of dormant and growing season burning on surface fuels and potential fire behavior in northern Florida longleaf pine (Pinus palustris) flatwoods

Treesearch

James B. Cronan; Clinton S. Wright; Maria Petrova

2015-01-01

Prescribed fire is widely used to manage fuels in high-frequency, low-severity fire regimes including pine flatwoods of the southeastern USA where prescribed burning during the growing season (the frost-free period during the calendar year) has become more common in recent decades. Growing season prescribed fires address ecological management objectives that focus on...

Fuel Preheat Effects on Soot-Field Structure in Laminar Gas Jet Diffusion Flames Burning in 0-g and 1-g

NASA Technical Reports Server (NTRS)

Konsur, Bogdan; Megaridis, Constantine M.; Griffin, Devon W.

1999-01-01

An experimental investigation conducted at the 2.2-s drop tower of the NASA Lewis Research Center is presented to quantify the influence of moderate fuel preheat on soot-field structure within 0-g laminar gas jet diffusion flames. Parallel work in 1-g is also presented to delineate the effect of elevated fuel temperatures on soot-field structure in buoyant flames. The experimental methodology implements jet diffusion flames of nitrogen-diluted acetylene fuel burning in quiescent air at atmospheric pressure. Fuel preheat of approximately 100 K in the 0-g laminar jet diffusion flames is found to reduce soot loadings in the annular region, but causes an increase in soot volume fractions at the centerline. In addition, fuel preheat reduces the radial extent of the soot field in 0-g. In 1-g, the same fuel preheat levels have a more moderated influence on soot loadings in the annular region, but are also seen to enhance soot concentrations near the axis low in the flame. The increased soot loadings near the flame centerline, as caused by fuel preheat, are consistent with the hypothesis that preheat levels of approximately 100 K enhance fuel pyrolysis rates. The results show that the growth stage of particles transported along the soot annulus is shortened both in 1-g and 0-g when elevated fuel temperatures are used.

Combustion of liquid fuel droplets in supercritical conditions

NASA Technical Reports Server (NTRS)

Shuen, J. S.; Yang, Vigor

1991-01-01

A comprehensive analysis of liquid-fuel droplet combustion in both sub- and super-critical environments has been conducted. The formulation is based on the complete conservation equations for both gas and liquid phases, and accommodates finite-rate chemical kinetics and a full treatment of liquid-vapor phase equilibrium at the droplet surface. The governing equations and the associated interface boundary conditions are solved numerically using a fully coupled, implicit scheme with the dual time-stepping integration technique. The model is capable of treating the entire droplet history, including the transition from the subcritical to the supercritical state. As a specific example, the combustion of n-pentane fuel droplets in air is studied for pressures of 5-140 atm. Results indicate that the ambient gas pressure exerts significant control of droplet gasification and burning processes through its influences on the fluid transport, gas/liquid interface thermodynamics, and chemical reactions. The droplet gasification rate increases progressively with pressure. However, the data for the overall burnout time exhibits a significant variation near the critical burning pressure, mainly as a result of reduced mass-diffusion rate and latent heat of vaporization with increased pressure. The influence of droplet size on the burning characteristics is also noted.

Effect of primary-zone water injection on pollutants from a combustor burning liquid ASTM A-1 and vaporized propane fuels

NASA Technical Reports Server (NTRS)

Ingebo, R. D.; Norgren, C. T.

1973-01-01

A combustor segment 0.457 meter (18 in.) long with a maximum cross section of 0.153 by 0.305 meter (6 by 12 in.) was operated at inlet-air temperatures of 590 and 700 K, inlet-air pressures of 4 and 10 atmospheres, and fuel-air ratios of 0.014 and 0.018 to determine the effect of primary-zone water injection on pollutants from burning either propane or ASTM A-1 fuel. At a simulated takeoff condition of 10 atmospheres and 700 K, multiple-orifice nozzles used to inject water at 1 percent of the airflow rate reduced nitrogen oxides 75 percent with propane and 65 percent with ASTM A-1 fuel. Although carbon monoxide and unburned hydrocarbons increased with water injection, they remained relatively low; and smoke numbers were well below the visibility limit.

Characterization of primary organic aerosol emissions from meat cooking, trash burning, and motor vehicles with high-resolution aerosol mass spectrometry and comparison with ambient and chamber observations.

PubMed

Mohr, Claudia; Huffman, Alex; Cubison, Michael J; Aiken, Allison C; Docherty, Kenneth S; Kimmel, Joel R; Ulbrich, Ingrid M; Hannigan, Michael; Jimenez, Jose L

2009-04-01

Organic aerosol (OA) emissions from motor vehicles, meat-cooking and trash burning are analyzed here using a high-resolution aerosol mass spectrometer (AMS). High resolution data show that aerosols emitted by combustion engines and plastic burning are dominated by hydrocarbon-like organic compounds. Meat cooking and especially paper burning emissions contain significant fractions of oxygenated organic compounds; however, their unit-resolution mass spectral signatures are very similar to those from ambient hydrocarbon-like OA, and very different from the mass spectra of ambient secondary or oxygenated OA (OOA). Thus, primary OA from these sources is unlikelyto be a significant direct source of ambient OOA. There are significant differences in high-resolution tracer m/zs that may be useful for differentiating some of these sources. Unlike in most ambient spectra, all of these sources have low total m/z 44 and this signal is not dominated by the CO2+ ion. All sources have high m/z 57, which is low during high OOA ambient periods. Spectra from paper burning are similar to some types of biomass burning OA, with elevated m/z 60. Meat cooking aerosols also have slightly elevated m/z 60, whereas motor vehicle emissions have very low signal at this m/z.

Improved hybrid rocket fuel

NASA Technical Reports Server (NTRS)

Dean, David L.

1995-01-01

McDonnell Douglas Aerospace, as part of its Independent R&D, has initiated development of a clean burning, high performance hybrid fuel for consideration as an alternative to the solid rocket thrust augmentation currently utilized by American space launch systems including Atlas, Delta, Pegasus, Space Shuttle, and Titan. It could also be used in single stage to orbit or as the only propulsion system in a new launch vehicle. Compared to solid propellants based on aluminum and ammonium perchlorate, this fuel is more environmentally benign in that it totally eliminates hydrogen chloride and aluminum oxide by products, producing only water, hydrogen, nitrogen, carbon oxides, and trace amounts of nitrogen oxides. Compared to other hybrid fuel formulations under development, this fuel is cheaper, denser, and faster burning. The specific impulse of this fuel is comparable to other hybrid fuels and is between that of solids and liquids. The fuel also requires less oxygen than similar hybrid fuels to produce maximum specific impulse, thus reducing oxygen delivery system requirements.

In Situ Burning of Oil Spills

PubMed Central

Evans, David D.; Mulholland, George W.; Baum, Howard R.; Walton, William D.; McGrattan, Kevin B.

2001-01-01

For more than a decade NIST conducted research to understand, measure and predict the important features of burning oil on water. Results of that research have been included in nationally recognized guidelines for approval of intentional burning. NIST measurements and predictions have played a major role in establishing in situ burning as a primary oil spill response method. Data are given for pool fire burning rates, smoke yield, smoke particulate size distribution, smoke aging, and polycyclic aromatic hydrocarbon content of the smoke for crude and fuel oil fires with effective diameters up to 17.2 m. New user-friendly software, ALOFT, was developed to quantify the large-scale features and trajectory of wind blown smoke plumes in the atmosphere and estimate the ground level smoke particulate concentrations. Predictions using the model were tested successfully against data from large-scale tests. ALOFT software is being used by oil spill response teams to help assess the potential impact of intentional burning. PMID:27500022

Critical issues in burn care.

PubMed

Holmes, James H

2008-01-01

Burn care, especially for serious burn injuries, represents a considerable challenge for the healthcare system. The American Burn Association has established a number of strategies for the management of burn patients and dedicates its efforts and resources to promoting and supporting burn-related research, education, care, rehabilitation, and prevention, often in collaboration with other organizations. The American Burn Association has recommended that patients with serious burns be referred to a designated burn center, ie, a hospital outfitted with specialized personnel and equipment dedicated to burn care. Burn centers have been operational for over 50 years, but the complexity and costs of providing specialized burn care have given rise to a number of critical administrative and political issues. These include logistical limitations imposed by the uneven national distribution of burn centers and a potential shortage of burn beds, both during everyday conditions and in the event of a mass disaster. Burn surgeon shortages have also been identified, stemming, in part, from a lack of specialized burn care training opportunities. There is currently a lack of quality outcome data to support evidence-based recommendations for burn care, and burn care centers are compromised by problems obtaining reimbursement for the care of uninsured and publicly insured out-of-state burn patients. Initiatives are underway to maintain efficient burn care facilities that are fully funded, easily accessible, and most importantly, provide optimal, evidence-based care on a daily basis, and are well-equipped to handle a surge of patients during a disaster situation.

The effect of water injection on nitric oxide emissions of a gas turbine combustor burning ASTM Jet-A fuel

NASA Technical Reports Server (NTRS)

Marchionna, N. R.; Diehl, L. A.; Trout, A. M.

1973-01-01

Tests were conducted to determine the effect of water injection on oxides of nitrogen (NOx) emissions of a full annular, ram induction gas turbine combustor burning ASTM Jet-A fuel. The combustor was operated at conditions simulating sea-level takeoff and cruise conditions. Water at ambient temperature was injected into the combustor primary zone at water-fuel ratios up to 2. At an inlet-air temperature of 589 K (600 F) water injection decreased the NOx emission index at a constant exponential rate: NOx = NOx (o) e to the -15 W/F power (where W/F is the water-fuel ratio and NOx(o) indicates the value with no injection). The effect of increasing combustor inlet-air temperature was to decrease the effect of the water injection. Other operating variables such as pressure and reference Mach number did not appear to significantly affect the percent reduction in NOx. Smoke emissions were found to decrease with increasing water injection.

Probing thermonuclear burning on accreting neutron stars

NASA Astrophysics Data System (ADS)

Keek, L.

2008-12-01

that the models need to be extended with a new heat source. Another rare phenomenon is the occurrence of bursts with recurrence times of less than 30 minutes. In a long set of observations of the source EXO 0748-676 we find for the first time triple bursts, where three bursts occur within 30 minutes. This time is too short to accrete new fuel for the next burst, which suggests that not all hydrogen and helium is burned during the first burst. Finally, using a hydrodynamic stellar evolution code we create a multi-zone numerical model of the neutron star envelope. For the first time we include mixing due to rotation and a rotationally induced magnetic field. We find that thermonuclear burning proceeds in a stable manner at a lower heat flux of the crust for models including mixing. This may explain the observed transition of stable to unstable burning at a lower mass accretion rate than models previously predicted.

Production of N2O5 and ClNO2 through Nocturnal Processing of Biomass-Burning Aerosol.

PubMed

Ahern, Adam T; Goldberger, Lexie; Jahl, Lydia; Thornton, Joel; Sullivan, Ryan C

2018-01-16

Biomass burning is a source of both particulate chloride and nitrogen oxides, two important precursors for the formation of nitryl chloride (ClNO 2 ), a source of atmospheric oxidants that is poorly prescribed in atmospheric models. We investigated the ability of biomass burning to produce N 2 O 5 (g) and ClNO 2 (g) through nocturnal chemistry using authentic biomass-burning emissions in a smog chamber. There was a positive relationship between the amount of ClNO 2 formed and the total amount of particulate chloride emitted and with the chloride fraction of nonrefractory particle mass. In every fuel tested, dinitrogen pentoxide (N 2 O 5 ) formed quickly, following the addition of ozone to the smoke aerosol, and ClNO 2 (g) production promptly followed. At atmospherically relevant relative humidities, the particulate chloride in the biomass-burning aerosol was rapidly but incompletely displaced, likely by the nitric acid produced largely by the heterogeneous uptake of N 2 O 5 (g). Despite this chloride acid displacement, the biomass-burning aerosol still converted on the order of 10% of reacted N 2 O 5 (g) into ClNO 2 (g). These experiments directly confirm that biomass burning is a potentially significant source of atmospheric N 2 O 5 and ClNO 2 to the atmosphere.

Indoor concentrations of nitrogen dioxide and sulfur dioxide from burning solid fuels for cooking and heating in Yunnan Province, China.

PubMed

Seow, W J; Downward, G S; Wei, H; Rothman, N; Reiss, B; Xu, J; Bassig, B A; Li, J; He, J; Hosgood, H D; Wu, G; Chapman, R S; Tian, L; Wei, F; Caporaso, N E; Vermeulen, R; Lan, Q

2016-10-01

The Chinese national pollution census has indicated that the domestic burning of solid fuels is an important contributor to nitrogen dioxide (NO2 ) and sulfur dioxide (SO2 ) emissions in China. To characterize indoor NO2 and SO2 air concentrations in relation to solid fuel use and stove ventilation in the rural counties of Xuanwei and Fuyuan, in Yunnan Province, China, which have among the highest lung cancer rates in the nation, a total of 163 participants in 30 selected villages were enrolled. Indoor 24-h NO2 and SO2 samples were collected in each household over two consecutive days. Compared to smoky coal, smokeless coal use was associated with higher NO2 concentrations [geometric mean (GM) = 132 μg/m(3) for smokeless coal and 111 μg/m(3) for smoky coal, P = 0.065] and SO2 [limit of detection = 24 μg/m(3) ; percentage detected (%Detect) = 86% for smokeless coal and 40% for smoky coal, P < 0.001]. Among smoky coal users, significant variation of NO2 and SO2 air concentrations was observed across different stove designs and smoky coal sources in both counties. Model construction indicated that the measurements of both pollutants were influenced by stove design. This exposure assessment study has identified high levels of NO2 and SO2 as a result of burning solid fuels for cooking and heating. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Burned in: Fueling the Fire to Teach

ERIC Educational Resources Information Center

Friedman, Audrey A.; Reynolds, Luke

2011-01-01

Almost half of new teachers leave the profession within their first year. New teachers need support, mentoring, encouragement, and, most importantly, hope in order to survive the challenges of their first years of teaching. "Burned In" features essays from today's most visionary educators, including Jim Burke, Peter Elbow, James Loewen, Gregory…

Prescribed burning impact on forest soil properties--a Fuzzy Boolean Nets approach.

PubMed

Castro, Ana C Meira; Paulo Carvalho, Joao; Ribeiro, S

2011-02-01

The Portuguese northern forests are often and severely affected by wildfires during the Summer season. These occurrences significantly affect and negatively impact all ecosystems, namely soil, fauna and flora. In order to reduce the occurrences of natural wildfires, some measures to control the availability of fuel mass are regularly implemented. Those preventive actions concern mainly prescribed burnings and vegetation pruning. This work reports on the impact of a prescribed burning on several forest soil properties, namely pH, soil moisture, organic matter content and iron content, by monitoring the soil self-recovery capabilities during a one year span. The experiments were carried out in soil cover over a natural site of Andaluzitic schist, in Gramelas, Caminha, Portugal, which was kept intact from prescribed burnings during a period of four years. Soil samples were collected from five plots at three different layers (0-3, 3-6 and 6-18) 1 day before prescribed fire and at regular intervals after the prescribed fire. This paper presents an approach where Fuzzy Boolean Nets (FBN) and Fuzzy reasoning are used to extract qualitative knowledge regarding the effect of prescribed fire burning on soil properties. FBN were chosen due to the scarcity on available quantitative data. The results showed that soil properties were affected by prescribed burning practice and were unable to recover their initial values after one year. Copyright © 2010 Elsevier Inc. All rights reserved.

Spatial and temporal distribution of tropical biomass burning

NASA Astrophysics Data System (ADS)

Hao, Wei Min; Liu, Mei-Huey

1994-12-01

A database for the spatial and temporal distribution of the amount of biomass burned in tropical America, Africa, and Asia during the late 1970s is presented with a resolution of 5° latitude × 5° longitude. The sources of burning in each grid cell have been quantified. Savanna fires, shifting cultivation, deforestation, fuel wood use, and burning of agricultural residues contribute about 50, 24, 10, 11, and 5%, respectively, of total biomass burned in the tropics. Savanna fires dominate in tropical Africa, and forest fires dominate in tropical Asia. A similar amount of biomass is burned from forest and savanna fires in tropical America. The distribution of biomass burned monthly during the dry season has been derived for each grid cell using the seasonal cycles of surface ozone concentrations. Land use changes during the last decade could have a profound impact on the amount of biomass burned and the amount of trace gases and aerosol particles emitted.

High accuracy fuel flowmeter. Phase 2C and 3: The mass flowrate calibration of high accuracy fuel flowmeters

NASA Technical Reports Server (NTRS)

Craft, D. William

1992-01-01

A facility for the precise calibration of mass fuel flowmeters and turbine flowmeters located at AMETEK Aerospace Products Inc., Wilmington, Massachusetts is described. This facility is referred to as the Test and Calibration System (TACS). It is believed to be the most accurate test facility available for the calibration of jet engine fuel density measurement. The product of the volumetric flow rate measurement and the density measurement, results in a true mass flow rate determination. A dual-turbine flowmeter was designed during this program. The dual-turbine flowmeter was calibrated on the TACS to show the characteristics of this type of flowmeter. An angular momentum flowmeter was also calibrated on the TACS to demonstrate the accuracy of a true mass flowmeter having a 'state-of-the-art' design accuracy.

Carbon, fire, and fuels: The importance of fuels and fuel characterization and the status of wildland fire fuels data for the United States

NASA Astrophysics Data System (ADS)

French, N. H. F.; Prichard, S.; McKenzie, D.; Kennedy, M. C.; Billmire, M.; Ottmar, R. D.; Kasischke, E. S.

2016-12-01

Quantification of emissions of carbon during combustion relies on knowing three general variables: how much landscape is impacted by fire (burn area), how much carbon is in that landscape (fuel loading), and fuel properties that determine the fraction that is consumed (fuel condition). These variables also determine how much carbon remains at the site in the form of unburned organic material or char, and therefore drive post-fire carbon dynamics and pools. In this presentation we review the importance of understanding fuel type, fuel loading, and fuel condition for quantifying carbon dynamics properly during burning and for measuring and mapping fuels across landscapes, regions, and continents. Variability in fuels has been shown to be a major driver of uncertainty in fire emissions, but has had little attention until recently. We review the current state of fuel characterization for fire management and carbon accounting, and present a new approach to quantifying fuel loading for use in fire-emissions mapping and for improving fire-effects assessment. The latest results of a study funded by the Joint Fire Science Program (JFSP) are presented, where a fuel loading database is being built to quantify variation in fuel loadings, as represented in the Fuel Characteristic Classification System (FCCS), across the conterminous US and Alaska. Statistical assessments of these data at multiple spatial scales will improve tools used by fire managers and scientists to quantify fire's impact on the land, atmosphere, and carbon cycle.

Assessing the regional impact of Indonesian biomass burning emissions based on organic molecular tracers and chemical mass balance modeling

NASA Astrophysics Data System (ADS)

Engling, G.; He, J.; Betha, R.; Balasubramanian, R.

2014-01-01

Biomass burning activities commonly occur in Southeast Asia (SEA), and are particularly intense in Indonesia during dry seasons. The effect of biomass smoke emissions on air quality in the city state of Singapore was investigated during a haze episode in October 2006. Substantially increased levels of airborne particulate matter (PM) and associated chemical species were observed during the haze period. Specifically, the enhancement in the concentration of molecular tracers for biomass combustion such as levoglucosan by as much as two orders of magnitude and diagnostic ratios of individual organic compounds indicated that biomass burning emissions caused a regional smoke haze episode due to their long-range transport by prevailing winds. With the aid of air mass back trajectories and chemical mass balance modeling, large-scale forest and peat fires in Sumatra and Kalimantan were identified as the sources of the smoke aerosol, exerting a significant impact on air quality in downwind areas, such as Singapore.

Assessing the regional impact of indonesian biomass burning emissions based on organic molecular tracers and chemical mass balance modeling

NASA Astrophysics Data System (ADS)

Engling, G.; He, J.; Betha, R.; Balasubramanian, R.

2014-08-01

Biomass burning activities commonly occur in Southeast Asia (SEA), and are particularly intense in Indonesia during the dry seasons. The effect of biomass smoke emissions on air quality in the city state of Singapore was investigated during a haze episode in October 2006. Substantially increased levels of airborne particulate matter (PM) and associated chemical species were observed during the haze period. Specifically, the enhancement in the concentration of molecular tracers for biomass combustion such as levoglucosan by as much as two orders of magnitude and the diagnostic ratios of individual organic compounds indicated that biomass burning emissions caused a regional smoke haze episode due to their long-range transport by prevailing winds. With the aid of air mass backward trajectories and chemical mass balance modeling, large-scale forest and peat fires in Sumatra and Kalimantan were identified as the sources of the smoke aerosol, exerting a significant impact on air quality in downwind areas, such as Singapore.

Highly time-resolved imaging of combustion and pyrolysis product concentrations in solid fuel combustion: NO formation in a burning cigarette.

PubMed

Zimmermann, Ralf; Hertz-Schünemann, Romy; Ehlert, Sven; Liu, Chuan; McAdam, Kevin; Baker, Richard; Streibel, Thorsten

2015-02-03

The highly dynamic, heterogeneous combustion process within a burning cigarette was investigated by a miniaturized extractive sampling probe (microprobe) coupled to photoionization mass spectrometry using soft laser single photon ionization (SPI) for online real-time detection of molecular ions of combustion and pyrolysis products. Research cigarettes smoked by a smoking machine are used as a reproducible model system for solid-state biomass combustion, which up to now is not addressable by current combustion-diagnostic tools. By combining repetitively recorded online measurement sequences from different sampling locations in an imaging approach, highly time- and space-resolved quantitative distribution maps of, e.g., nitrogen monoxide, benzene, and oxygen concentrations were obtained at a near microscopic level. The obtained quantitative distribution maps represent a time-resolved, movie-like imaging of the respective compound's formation and destruction zones in the various combustion and pyrolysis regions of a cigarette during puffing. Furthermore, spatially resolved kinetic data were ascertainable. The here demonstrated methodology can also be applied to various heterogenic combustion/pyrolysis or reaction model systems, such as fossil- or biomass-fuel pellet combustion or to a positional resolved analysis of heterogenic catalytic reactions.

A Burke-Schumann Analysis of Dual-Flame Structure Supported by a Burning Droplet

NASA Technical Reports Server (NTRS)

Nayagam, V.; Dietrich, D.; Williams, F. A.

2016-01-01

Droplet combustion experiments carried out onboard the International Space Station (ISS), using pure fuels and fuel mixtures, have shown that quasi-steady burning can be sustained by a non-traditional flame configuration, namely a "cool flame" burning in the "partial-burning" regime where both fuel and oxygen leak through the low-temperature controlled flame-sheet. Recent experiments involving large, bi-component fuel (n-decane and hexanol, 50/50 by volume) droplets at elevated pressures show that the visible, hot flame becomes extremely weak while the burning rate remains relatively high, suggesting the possibility of simultaneous presence of "cool" and "hot" flames of roughly equal importance. The radiant output from these bi-component droplets is relatively high and cannot be accounted for only by the presence of a visible hot-flame. In this analysis we explore the theoretical possibility of a dual-flame structure, where one flame lies close to the droplet surface called the "cool-flame," and other farther away from the droplet surface, termed the "hot-flame." A Burke-Schumann analysis of this dual-structure seems to indicate such flame structures are possible over a narrow range of initial conditions. Theoretical results can be compared against available experimental data for pure and bi-component fuel droplet combustion to test how realistic the model may be.

Impacts of Growing-Season Prescibed Burns in the Florida Pine Flatwoods Type

Treesearch

Kenneth W. Outcalt; John L. Foltz

2004-01-01

A considerable amount of experience and knowledge has been gained in the application of growing-season burning in pine communities across the Southeast. However, there is still concern that burning during this season will cause increased tree mortality and/or growth loss. Pine flatwoods stands in south Florida with 3 years of fuel accumulation were burned during the...

Fuel Cycle Performance of Thermal Spectrum Small Modular Reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Worrall, Andrew; Todosow, Michael

2016-01-01

Small modular reactors may offer potential benefits, such as enhanced operational flexibility. However, it is vital to understand the holistic impact of small modular reactors on the nuclear fuel cycle and fuel cycle performance. The focus of this paper is on the fuel cycle impacts of light water small modular reactors in a once-through fuel cycle with low-enriched uranium fuel. A key objective of this paper is to describe preliminary reactor core physics and fuel cycle analyses conducted in support of the U.S. Department of Energy Office of Nuclear Energy Fuel Cycle Options Campaign. Challenges with small modular reactors include:more » increased neutron leakage, fewer assemblies in the core (and therefore fewer degrees of freedom in the core design), complex enrichment and burnable absorber loadings, full power operation with inserted control rods, the potential for frequent load-following operation, and shortened core height. Each of these will impact the achievable discharge burn-up in the reactor and the fuel cycle performance. This paper summarizes the results of an expert elicitation focused on developing a list of the factors relevant to small modular reactor fuel, core, and operation that will impact fuel cycle performance. Preliminary scoping analyses were performed using a regulatory-grade reactor core simulator. The hypothetical light water small modular reactor considered in these preliminary scoping studies is a cartridge type one-batch core with 4.9% enrichment. Some core parameters, such as the size of the reactor and general assembly layout, are similar to an example small modular reactor concept from industry. The high-level issues identified and preliminary scoping calculations in this paper are intended to inform on potential fuel cycle impacts of one-batch thermal spectrum SMRs. In particular, this paper highlights the impact of increased neutron leakage and reduced number of batches on the achievable burn-up of the reactor. Fuel cycle

Smoke from wildfires and prescribed burning in Australia: effects on human health and ecosystems

Treesearch

Tina Bell; Mark Adams

2009-01-01

Much of Australia is seasonally hot and dry, and fuel beds can become very flammable. Biomass burning ranges from annual savanna fires in the north to sporadic but extensive forest fires in the south. In addition, prescribed burning (the controlled application of fire) is being used more frequently as a means of reducing fuel loads, for maintenance of plant and animal...

Solid-fuel cook stoves: Fuel efficiency and emissions testing--Austin

EPA Science Inventory

The World Health Organization estimates that approximately 1.6 million people prematurely die each year due to exposure to air pollutants from burning solid fuels for residential cooking and heating (WHO, 2010). Residential solid-fuel use accounts for approximately 25 percent of ...

Analysis of Parallel Burn Without Crossfeed TSTO RLV Architectures and Comparison to Parallel Burn With Crossfeed and Series Burn Architectures

NASA Technical Reports Server (NTRS)

Smith, Garrett; Phillips, Alan

2002-01-01

There are currently three dominant TSTO class architectures. These are Series Burn (SB), Parallel Burn with crossfeed (PBw/cf), and Parallel Burn without crossfeed (PBncf). The goal of this study was to determine what factors uniquely affect PBncf architectures, how each of these factors interact, and to determine from a performance perspective whether a PBncf vehicle could be competitive with a PBw/cf or SB vehicle using equivalent technology and assumptions. In all cases, performance was evaluated on a relative basis for a fixed payload and mission by comparing gross and dry vehicle masses of a closed vehicle. Propellant combinations studied were LOX: LH2 propelled orbiter and booster (HH) and LOX: Kerosene booster with LOX: LH2 orbiter (KH). The study conclusions were: 1) a PBncf orbiter should be throttled as deeply as possible after launch until the staging point. 2) a detailed structural model is essential to accurate architecture analysis and evaluation. 3) a PBncf TSTO architecture is feasible for systems that stage at mach 7. 3a) HH architectures can achieve a mass growth relative to PBw/cf of < 20%. 3b) KH architectures can achieve a mass growth relative to Series Burn of < 20%. 4) center of gravity (CG) control will be a major issue for a PBncf vehicle, due to the low orbiter specific thrust to weight ratio and to the position of the orbiter required to align the nozzle heights at liftoff. 5 ) thrust to weight ratios of 1.3 at liftoff and between 1.0 and 0.9 when staging at mach 7 appear to be close to ideal for PBncf vehicles. 6) performance for all vehicles studied is better when staged at mach 7 instead of mach 5. The study showed that a Series Burn architecture has the lowest gross mass for HH cases, and has the lowest dry mass for KH cases. The potential disadvantages of SB are the required use of an air-start for the orbiter engines and potential CG control issues. A Parallel Burn with crossfeed architecture solves both these problems, but the

Relationship of fuel size and spacing to combustion characteristics of laboratory fuel cribs

Treesearch

Hal E. Anderson

1990-01-01

Flaming combustion in cribs of large woody fuels, thickness 5 cm or greater, is not sustained when fuel spacing ratio, fuel edge-to-edge separation distance to fuel thickness, is greater than 3:1. The flame length associated with the large-fuel burning rate was found to drop rapidly when the large-fuel spacing ratio increases beyond 2.23:1. This supports the critical...

Testing a basic assumption of shrubland fire management: Does the hazard of burning increase with the age of fuels?

USGS Publications Warehouse

Moritz, Max A.; Keeley, Jon E.; Johnson, Edward A.; Schaffner, Andrew A.

2004-01-01

This year's catastrophic wildfires in southern California highlight the need for effective planning and management for fire-prone landscapes. Fire frequency analysis of several hundred wildfires over a broad expanse of California shrublands reveals that there is generally not, as is commonly assumed, a strong relationship between fuel age and fire probabilities. Instead, the hazard of burning in most locations increases only moderately with time since the last fire, and a marked age effect of fuels is observed only in limited areas. Results indicate a serious need for a re-evaluation of current fire management and policy, which is based largely on eliminating older stands of shrubland vegetation. In many shrubland ecosystems exposed to extreme fire weather, large and intense wildfires may need to be factored in as inevitable events.

Phenolic compounds of Pinus laricio needles: a bioindicator of the effects of prescribed burning in function of season.

PubMed

Cannac, Magali; Pasqualini, Vanina; Barboni, Toussaint; Morandini, Frederic; Ferrat, Lila

2009-07-15

Fire is a dominant ecological factor in Mediterranean-type ecosystems. Forest management includes many preventive tools, in particular for fire prevention, such as mechanical treatments and prescribed burning. Prescribed burning is a commonly used method for treating fuel loads, but fuel reduction targets for reducing wildfire hazards must be balanced against fuel retention targets in order to maintain habitat and other forest functions. This approach was used on Pinus nigra ssp laricio var. Corsicana, a pine endemic to Corsica of great ecological and economic importance. Many studies of plant phenolic compounds have been carried out concerning responses to various stresses. The aim of this study was to understand i) the effects of prescribed burning 1 to 16 months later and ii) the effects of the seasonality of burning, spring or fall, on the production of phenolic compounds in Pinus laricio. After prescribed burning conducted in spring, Pinus laricio increases the synthesis of total phenolic compounds for a period of 7 months. The increase is greater after spring-burning than fall-burning. With regard to simple phenols, only dihydroferulic acid responds about 1 year after both types of prescribed burning. The causes of these increases are discussed in this paper. Total phenolic compounds could be used as a bioindicator for the short-term response of Pinus laricio needles to prescribed burning. Simple phenols may be useful for revealing the medium-term effects of prescribed burning. The results of this study include recommending forest managers to use prescribed burning in the fall rather than spring to reduce fuel loads and have less impact on the trees.

Understanding Kelvin-Helmholtz instability in paraffin-based hybrid rocket fuels

NASA Astrophysics Data System (ADS)

Petrarolo, Anna; Kobald, Mario; Schlechtriem, Stefan

2018-04-01

Liquefying fuels show higher regression rates than the classical polymeric ones. They are able to form, along their burning surface, a low viscosity and surface tension liquid layer, which can become unstable (Kelvin-Helmholtz instability) due to the high velocity gas flow in the fuel port. This causes entrainment of liquid droplets from the fuel surface into the oxidizer gas flow. To better understand the droplets entrainment mechanism, optical investigations on the combustion behaviour of paraffin-based hybrid rocket fuels in combination with gaseous oxygen have been conducted in the framework of this research. Combustion tests were performed in a 2D single-slab burner at atmospheric conditions. High speed videos were recorded and analysed with two decomposition techniques. Proper orthogonal decomposition (POD) and independent component analysis (ICA) were applied to the scalar field of the flame luminosity. The most excited frequencies and wavelengths of the wave-like structures characterizing the liquid melt layer were computed. The fuel slab viscosity and the oxidizer mass flow were varied to study their influence on the liquid layer instability process. The combustion is dominated by periodic, wave-like structures for all the analysed fuels. Frequencies and wavelengths characterizing the liquid melt layer depend on the fuel viscosity and oxidizer mass flow. Moreover, for very low mass flows, no wavelength peaks are detected for the higher viscosity fuels. This is important to better understand and predict the onset and development of the entrainment process, which is connected to the amplification of the longitudinal waves.

Organic aerosol evaporation and formation in biomass-burning plumes: The competition between dilution and chemistry

NASA Astrophysics Data System (ADS)

Pierce, J. R.; Kreidenweis, S. M.; Bian, Q.; Jathar, S.; Kodros, J.; Barsanti, K.; Hatch, L. E.; May, A.

2017-12-01

Secondary organic aerosol (SOA) has been shown to form in biomass-burning emissions in laboratory and field studies. However, there is significant variability among studies in mass enhancement, which could be due to differences in fuels, fire conditions, dilution, and/or limitations of laboratory experiments and observations. This study focuses on understanding processes affecting biomass-burning SOA formation in ambient plumes. The plume dilution rate impacts the organic partitioning between the gas and particle phases, which may impact the potential for SOA to form as well as the rate of SOA formation. We use an aerosol microphysics model that includes representations of volatility and oxidation chemistry to estimate SOA formation in the smoke emitted into the atmosphere. We add Gaussian dispersion to our aerosol microphysical model to estimate how SOA formation may vary under different ambient-plume conditions (e.g. fire size, emission mass flux, atmospheric stability). Smoke from small fires, such as typical prescribed burns, dilutes rapidly, which drives evaporation of organic vapor from the particle phase, leading to more effective SOA formation. Emissions from large fires, such as intense wildfires, dilute slowly, suppressing OA evaporation and subsequent SOA formation in the near field. We also demonstrate that different approaches to the calculation of OA enhancement in ambient plumes can lead to different conclusions regarding SOA formation. Normalized OA mass enhancement ratios of around 1 calculated using an inert tracer, such as black carbon or CO, have traditionally been interpreted as exhibiting little or no SOA formation; however, we show that SOA formation may have greatly contributed to the mass in these plumes.

Numerical research of reburning-process of burning of coal-dust torch

NASA Astrophysics Data System (ADS)

Trinchenko, Alexey; Paramonov, Aleksandr; Kadyrov, Marsel; Koryabkin, Aleksey

2017-10-01

This work is dedicated to numerical research of ecological indicators of technological method of decrease in emissions of nitrogen oxides at combustion of solid fuel in coal-dust torch to improve the energy efficiency of steam boilers. The technology of step burning with additional input in zone of the maximum concentration of pollutant of strongly crushed fuel for formation of molecular nitrogen on surface of the burning carbon particles is considered. Results of modeling and numerical researches of technology, their analysis and comparison with the experimental data of the reconstructed boiler are given. Results of work show that input of secondary fuel allows to reduce emissions of nitrogen oxides by boiler installation without prejudice to its economic indicators.

Determination of total and polycyclic aromatic hydrocarbons in aviation jet fuel.

PubMed

Bernabei, M; Reda, R; Galiero, R; Bocchinfuso, G

2003-01-24

The aviation jet fuel widely used in turbine engine aircraft is manufactured from straight-run kerosene. The combustion quality of jet fuel is largely related to the hydrocarbon composition of the fuel itself; paraffins have better burning properties than aromatic compounds, especially naphthalenes and light polycyclic aromatic hydrocarbons (PAHs), which are characterised as soot and smoke producers. For this reason the burning quality of fuel is generally measured as smoke fermation. This evaluation is carried out with UV spectrophotometric determination of total naphthalene hydrocarbons and a chromatographic analysis to determine the total aromatic compounds. These methods can be considered insufficient to evaluate the human health impact of these compounds due to their inability to measure trace (ppm) amounts of each aromatic hyrcarbon and each PAH in accordance with limitations imposed because of their toxicological properties. In this paper two analytical methods are presented. Both are based on a gas chromatographic technique with a mass detector operating in be selected ion monitoring mode. The first method was able to determine more than 60 aromatic hydrocarbons in a fuel sample in a 35-min chromatographic run, while the second was able to carry out the analysis of more than 30 PAHs in a 40-min chromatographic run. The linearity and sensitivity of the methods in measuring these analytes at trace levels are described.

Determination of mixing state and sources of wintertime organic aerosol in Paris using single particle mass spectrometry

NASA Astrophysics Data System (ADS)

Healy, R. M.; Sciare, J.; Poulain, L.; Wiedensohler, A.; Jeong, C.; McGuire, M.; Evans, G. J.; McGillicuddy, E.; O'Connor, I. P.; Sodeau, J. R.; Wenger, J.

2012-12-01

The size-resolved chemical composition of single particles at an urban background site in Paris, France, was determined using an Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS) as part of the MEGAPOLI winter campaign in January/February 2010. A variety of mixing states were identified for organic aerosol by mass spectral clustering and apportioned to both fossil fuel and biomass burning sources. The ATOFMS data were scaled in order to produce mass concentration estimates for each organic aerosol particle type identified. Potassium-containing organic aerosol internally mixed with nitrate, associated with local wood burning, was observed to dominate during periods characterised by marine air masses. Sulfate-rich potassium-containing organic aerosol, associated with transboundary transport of biomass burning emissions, dominated during periods influenced by continental air masses. The scaled total mass concentration for potassium-containing particles was well correlated (R2 = 0.79) with concurrent measurements of potassium mass concentration measured with a Particle-Into-Liquid-Sampler (PILS). Another organic particle type, also containing potassium but rich in trimethylamine and sulfate, was detected exclusively during continental air mass events. These particles are postulated to have accumulated gas phase trimethylamine through heterogeneous reaction before arriving at the sampling site. Potential source regions for transboundary organic aerosols have been investigated using the potential source contribution function (PSCF). Comparison with aerosol mass spectrometer (AMS) measurements will also be discussed.

Photos for Estimating Residue Loadings Before and After Burning in Southern Appalachian Mixed Pine - Hardwood Clearcuts

Treesearch

Bradford M. Sanders; David H. van Lear

1988-01-01

Paired photographs show fuel conditions before and after burning in recently clearcut stands of mixed pine-hardwoods in the Southern Appalachians. Comparison with the photos permits fast assessment of fuel loading and probable burning success. Information with each photo includes measured weights, volumes, and other residue data, information about the timber stand and...

Characterization of PM 2.5 collected during broadcast and slash-pile prescribed burns of predominately ponderosa pine forests in northern Arizona

NASA Astrophysics Data System (ADS)

Robinson, Marin S.; Zhao, Min; Zack, Lindsay; Brindley, Christine; Portz, Lillian; Quarterman, Matthew; Long, Xiufen; Herckes, Pierre

2011-04-01

Prescribed burning, in combination with mechanical thinning, is a successful method for reducing heavy fuel loads from forest floors and thereby lowering the risk of catastrophic wildfire. However, an undesirable consequence of managed fire is the production of fine particulate matter or PM 2.5 (particles ≤2.5 μm in aerodynamic diameter). Wood-smoke particulate data from 21 prescribed burns are described, including results from broadcast and slash-pile burns. All PM 2.5 samples were collected in situ on day 1 (ignition) or day 2. Samples were analyzed for mass, polycyclic aromatic hydrocarbons (PAHs), inorganic elements, organic carbon (OC), and elemental carbon (EC). Results were characteristic of low-intensity, smoldering fires. PM 2.5 concentrations varied from 523 to 8357 μg m -3 and were higher on day 1. PAH weight percents (19 PAHs) were higher in slash-pile burns (0.21 ± 0.08% OC) than broadcast burns (0.07 ± 0.03% OC). The major elements were K, Cl, S, and Si. OC and EC values averaged 66 ± 7 and 2.8 ± 1.4% PM 2.5, respectively, for all burns studied, in good agreement with literature values for smoldering fires.

Characterization of PM(2.5) collected during broadcast and slash-pile prescribed burns of predominately ponderosa pine forests in northern Arizona.

PubMed

Robinson, Marin S; Zhao, Min; Zack, Lindsay; Brindley, Christine; Portz, Lillian; Quarterman, Matthew; Long, Xiufen; Herckes, Pierre

2011-04-01

Prescribed burning, in combination with mechanical thinning, is a successful method for reducing heavy fuel loads from forest floors and thereby lowering the risk of catastrophic wildfire. However, an undesirable consequence of managed fire is the production of fine particulate matter or PM(2.5) (particles ≤2.5 µm in aerodynamic diameter). Wood-smoke particulate data from 21 prescribed burns are described, including results from broadcast and slash-pile burns. All PM(2.5) samples were collected in situ on day 1 (ignition) or day 2. Samples were analyzed for mass, polycyclic aromatic hydrocarbons (PAHs), inorganic elements, organic carbon (OC), and elemental carbon (EC). Results were characteristic of low intensity, smoldering fires. PM(2.5) concentrations varied from 523 to 8357 µg m(-3) and were higher on day 1. PAH weight percents (19 PAHs) were higher in slash-pile burns (0.21 ± 0.08% OC) than broadcast burns (0.07 ± 0.03% OC). The major elements were K, Cl, S, and Si. OC and EC values averaged 66 ± 7 and 2.8 ± 1.4% PM(2.5), respectively, for all burns studied, in good agreement with literature values for smoldering fires.

Characterization of PM2.5 collected during broadcast and slash-pile prescribed burns of predominately ponderosa pine forests in northern Arizona

PubMed Central

Zhao, Min; Zack, Lindsay; Brindley, Christine; Portz, Lillian; Quarterman, Matthew; Long, Xiufen; Herckes, Pierre

2011-01-01

Prescribed burning, in combination with mechanical thinning, is a successful method for reducing heavy fuel loads from forest floors and thereby lowering the risk of catastrophic wildfire. However, an undesirable consequence of managed fire is the production of fine particulate matter or PM2.5 (particles ≤2.5 µm in aerodynamic diameter). Wood-smoke particulate data from 21 prescribed burns are described, including results from broadcast and slash-pile burns. All PM2.5 samples were collected in situ on day 1 (ignition) or day 2. Samples were analyzed for mass, polycyclic aromatic hydrocarbons (PAHs), inorganic elements, organic carbon (OC), and elemental carbon (EC). Results were characteristic of low intensity, smoldering fires. PM2.5 concentrations varied from 523 to 8357 µg m−3 and were higher on day 1. PAH weight percents (19 PAHs) were higher in slash-pile burns (0.21 ± 0.08% OC) than broadcast burns (0.07 ± 0.03% OC). The major elements were K, Cl, S, and Si. OC and EC values averaged 66 ± 7 and 2.8 ± 1.4% PM2.5, respectively, for all burns studied, in good agreement with literature values for smoldering fires. PMID:21625396

Fuel Regression Characteristics of Cascaded Multistage Impinging-Jet (CAMUI) Type Hybrid Rocket

NASA Astrophysics Data System (ADS)

Itoh, Mitsunori; Maeda, Takenori; Kakikura, Akihito; Kaneko, Yudai; Mori, Kazuhiro; Nakashima, Takuji; Wakita, Masashi; Uematsu, Tsutomu; Totani, Tsuyoshi; Oshima, Nobuyuki; Nagata, Harunori

A series of lab-scale firing tests was conducted to investigate the fuel regression characteristics of Cascaded Multistage Impinging-jet (CAMUI) type hybrid rocket. The alternative fuel grain used in this rocket consists of a number of cylindrical fuel blocks with two ports, which were aligned along the axis of the combustion chamber with a small gap. The ports are aligned staggered with respect to ones of neighboring blocks so that the combustion gas flow impinges on the forward-end surface of each block. In this fuel grain, forward-end surfaces, back-end surfaces and ports of fuel blocks contribute as burning surfaces. Polyethylene and LOX were used as a propellant, and the tests were conducted at the chamber pressure of 0.5 2MPa and the mass flux of 50 200kg/m2s. Main results obtained in this study are in the followings: The regression rate of each surface was obtained as a function of the propellant mass flux and local equivalent ratio of the combustion gas. At back-end surfaces the regression rate has a high sensitivity on the gap height of neighboring fuel blocks. These fuel regression characteristics will contribute as fundamental data to improve the optimum design of the fuel grain.

Radioactivity of spent TRIGA fuel

NASA Astrophysics Data System (ADS)

Usang, M. D.; Nabil, A. R. A.; Alfred, S. L.; Hamzah, N. S.; Abi, M. J. B.; Rawi, M. Z. M.; Abu, M. P.

2015-04-01

Some of the oldest TRIGA fuel in the Malaysian Reaktor TRIGA PUSPATI (RTP) is approaching the limit of its end of life with burn-up of around 20%. Hence it is prudent for us to start planning on the replacement of the fuel in the reactor and other derivative activities associated with it. In this regard, we need to understand all of the risk associated with such operation and one of them is to predict the radioactivity of the fuel, so as to estimate the safety of our working conditions. The radioactivity of several fuels are measured and compared with simulation results to confirm the burnup levels of the selected fuels. The radioactivity measurement are conducted inside the water tank to reduce the risk of exposure and in this case the detector wrapped in plastics are lowered under water. In nuclear power plant, the general practice was to continuously burn the fuel. In research reactor, most operations are based on the immediate needs of the reactor and our RTP for example operate periodically. By integrating the burnup contribution for each core configuration, we simplify the simulation of burn up for each core configuration. Our results for two (2) fuel however indicates that the dose from simulation underestimate the actual dose from our measurements. Several postulates are investigated but the underlying reason remain inconclusive.

Selective NOx Recirculation for Stationary Lean-Burn Natural Gas Engines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nigel N. Clark

Nitric oxide (NO) and nitrogen dioxide (NO2) generated by internal combustion (IC) engines are implicated in adverse environmental and health effects. Even though lean-burn natural gas engines have traditionally emitted lower oxides of nitrogen (NOx) emissions compared to their diesel counterparts, natural gas engines are being further challenged to reduce NOx emissions to 0.1 g/bhp-hr. The Selective NOx Recirculation (SNR) approach for NOx reduction involves cooling the engine exhaust gas and then adsorbing the NOx from the exhaust stream, followed by the periodic desorption of NOx. By sending the desorbed NOx back into the intake and through the engine, amore » percentage of the NOx can be decomposed during the combustion process. SNR technology has the support of the Department of Energy (DOE), under the Advanced Reciprocating Engine Systems (ARES) program to reduce NOx emissions to under 0.1 g/bhp-hr from stationary natural gas engines by 2010. The NO decomposition phenomenon was studied using two Cummins L10G natural gas fueled spark-ignited (SI) engines in three experimental campaigns. It was observed that the air/fuel ratio ({lambda}), injected NO quantity, added exhaust gas recirculation (EGR) percentage, and engine operating points affected NOx decomposition rates within the engine. Chemical kinetic model predictions using the software package CHEMKIN were performed to relate the experimental data with established rate and equilibrium models. The model was used to predict NO decomposition during lean-burn, stoichiometric burn, and slightly rich-burn cases with added EGR. NOx decomposition rates were estimated from the model to be from 35 to 42% for the lean-burn cases and from 50 to 70% for the rich-burn cases. The modeling results provided an insight as to how to maximize NOx decomposition rates for the experimental engine. Results from this experiment along with chemical kinetic modeling solutions prompted the investigation of rich-burn operating

Transverse liquid fuel jet breakup, burning, and ignition. M.S. Thesis

NASA Technical Reports Server (NTRS)

Li, Hsi-Shang

1990-01-01

An analytical study of the breakup, burning, and ignition of liquid fuels injected transversely into a hot air stream is conducted. The non-reacting liquid jet breakup location is determined by the local sonic point criterion. Two models, one employing analysis of an elliptical jet cross-section and the other employing a two-dimensional blunt body to represent the transverse jet, were used for sonic point calculations. An auxiliary criterion based on surface tension stability is used as a separate means of determining the breakup location. For the reacting liquid jet problem, a diffusion flame supported by a one-step chemical reaction within the gaseous boundary layer is solved along the ellipse surface in subsonic cross flow. Typical flame structures and concentration profiles were calculated for various locations along the jet cross-section as a function of upstream Mach numbers. The integration reaction rate along the jet cross-section is used to predict ignition position, which is found to be situated near the stagnation point. While a multi-step reaction is needed to represent the ignition process more accurately, the present calculation does yield reasonable predictions concerning ignition along a curved surface.

Oxidative potential of logwood and pellet burning particles assessed by a novel profluorescent nitroxide probe.

PubMed

Miljevic, B; Heringa, M F; Keller, A; Meyer, N K; Good, J; Lauber, A; Decarlo, P F; Fairfull-Smith, K E; Nussbaumer, T; Burtscher, H; Prevot, A S H; Baltensperger, U; Bottle, S E; Ristovski, Z D

2010-09-01

This study reports the potential toxicological impact of particles produced during biomass combustion by an automatic pellet boiler and a traditional logwood stove under various combustion conditions using a novel profluorescent nitroxide probe, BPEAnit. This probe is weakly fluorescent but yields strong fluorescence emission upon radical trapping or redox activity. Samples were collected by bubbling aerosol through an impinger containing BPEAnit solution, followed by fluorescence measurement. The fluorescence of BPEAnit was measured for particles produced during various combustion phases: at the beginning of burning (cold start), stable combustion after refilling with the fuel (warm start), and poor burning conditions. For particles produced by the logwood stove under cold-start conditions, significantly higher amounts of reactive species per unit of particulate mass were observed compared to emissions produced during a warm start. In addition, sampling of logwood burning emissions after passing through a thermodenuder at 250 degrees C resulted in an 80-100% reduction of the fluorescence signal of the BPEAnit probe, indicating that the majority of reactive species were semivolatile. Moreover, the amount of reactive species showed a strong correlation with the amount of particulate organic material. This indicates the importance of semivolatile organics in particle-related toxicity. Particle emissions from the pellet boiler, although of similar mass concentration, were not observed to lead to an increase in fluorescence signal during any of the combustion phases.

Brown carbon in fresh and aged biomass burning emissions

NASA Astrophysics Data System (ADS)

Saleh, R.; Robinson, E.; Tkacik, D. S.; Ahern, A.; Liu, S.; Aiken, A. C.; Sullivan, R. C.; Presto, A. A.; Dubey, M.; Donahue, N. M.; Robinson, A. L.

2013-12-01

To date, most climate forcing calculations treat black carbon (BC) and dust as the only particulate light absorbers. Numerous studies have shown that some organic aerosols (OA), referred to as brown carbon (BrC), also absorb light. BrC has been identified in biomass burning emissions; however, its light absorption properties are poorly constrained. Literature values of the imaginary part of the refractive indices of biomass burning OA (kOA) span two orders of magnitude. This variability, attributed to differences in fuel type and burning conditions, complicates the representation of biomass burning BrC in climate models. Proper accounting for BrC absorption in climate forcing calculations is of great importance. It can enhance the models' performance, bringing estimates of climate sensitivity to better agreement with observations. Here, we investigate the source of variability in absorptivity of biomass-burning OA observed in this study. We show that absorptivity is closely linked to OA volatility. Specifically, low-volatility organic compounds (LVOCs) are responsible for most of the light absorption, with effective kOA 1-2 orders of magnitude greater than the semi-volatile organic compounds (SVOCs). The effective kOA of biomass-burning emissions thus depends on the extent to which SVOCs partition to the condensed phase, which is sensitive to OA loading. kOA increases by a factor of 3-4 when the emissions are diluted from source concentrations (1-10 mg/m3) to atmospheric-like concentrations (1-10 μg/m3), as the partitioning of SVOCs shifts towards the gas phase. More importantly, we demonstrate that the effective kOA depends largely on burn conditions, and not fuel type. Burns which produce high levels of BC emit OA that is more absorptive than burns which produce low levels of BC. The dependence of kOA on OA loading and burn conditions can be parameterized as a function of a single property of the emissions, namely the BC-to-OA ratio. Specifically, kOA at

Air Pollution Episodes Associated with Prescribed Burns

NASA Astrophysics Data System (ADS)

Hart, M.; Di Virgilio, G.; Jiang, N.

2017-12-01

Air pollution events associated with wildfires have been associated with extreme health impacts. Prescribed burns are an important tool to reduce the severity of wildfires. However, if undertaken during unfavourable meteorological conditions, they too have the capacity to trigger extreme air pollution events. The Australian state of New South Wales has increased the annual average area treated by prescribed burn activities by 45%, in order to limit wildfire activity. Prescribed burns need to be undertaken during meteorological conditions that allow the fuel load to burn, while still allowing the burn to remain under control. These conditions are similar to those that inhibit atmospheric dispersion, resulting in a fine balance between managing fire risk and managing ambient air pollution. During prescribed burns, the Sydney air shed can experience elevated particulate matter concentrations, especially fine particulates (PM2.5) that occasionally exceed national air quality standards. Using pollutant and meteorological data from sixteen monitoring stations in Sydney we used generalized additive model and CART analyses to profile the meteorological conditions influencing air quality during planned burns. The insights gained from this study will help improve prescribed burn scheduling in order to reduce the pollution risk to the community, while allowing fire agencies to conduct this important work.

Life cycle assessment of vehicle lightweighting: a physics-based model of mass-induced fuel consumption.

PubMed

Kim, Hyung Chul; Wallington, Timothy J

2013-12-17

Lightweighting is a key strategy used to improve vehicle fuel economy. Replacing conventional materials (e.g., steel) with lighter alternatives (e.g., aluminum, magnesium, and composites) decreases energy consumption and greenhouse gas (GHG) emissions during vehicle use, but often increases energy consumption and GHG emissions during materials and vehicle production. Assessing the life-cycle benefits of mass reduction requires a quantitative description of the mass-induced fuel consumption during vehicle use. A new physics-based method for estimating mass-induced fuel consumption (MIF) is proposed. We illustrate the utility of this method by using publicly available data to calculate MIF values in the range of 0.2-0.5 L/(100 km 100 kg) based on 106 records of fuel economy tests by the U.S. Environmental Protection Agency for 2013 model year vehicles. Lightweighting is shown to have the most benefit when applied to vehicles with high fuel consumption and high power. Use of the physics-based model presented here would place future life cycle assessment studies of vehicle lightweighting on a firmer scientific foundation.

Soil heating and impact of prescribed burning

NASA Astrophysics Data System (ADS)

Stoof, Cathelijne

2016-04-01

Prescribed burning is highly uncommon in the Netherlands, where wildfire awareness is increasing but its risk management does not yet include fuel management strategies. A major exception is on two military bases, that need to burn their fields in winter and spring to prevent wildfires during summer shooting practice. Research on these very frequent burns has so far been limited to effects on biodiversity, yet site managers and policy makers have questions regarding the soil temperatures reached during these burns because of potential impact on soil properties and soil dwelling fauna. In March 2015, I therefore measured soil and litter temperatures under heath and grass vegetation during a prescribed burn on military terrain in the Netherlands. Soil and litter moisture were sampled pre- and post-fire, ash was collected, and fireline intensity was estimated from flame length. While standing vegetation was dry (0.13 g water/g biomass for grass and 0.6 g/g for heather), soil and litter were moist (0.21 cm3/cm3 and 1.6 g/g, respectively). Soil heating was therefore very limited, with maximum soil temperature at the soil-litter interface remaining being as low as 6.5 to 11.5°C, and litter temperatures reaching a maximum of 77.5°C at the top of the litter layer. As a result, any changes in physical properties like soil organic matter content and bulk density were not significant. These results are a first step towards a database of soil heating in relation to fuel load and fire intensity in this temperate country, which is not only valuable to increase understanding of the relationships between fire intensity and severity, but also instrumental in the policy debate regarding the sustainability of prescribed burns.

Aerial sampling of emissions from biomass pile burns in ...

EPA Pesticide Factsheets

Emissions from burning piles of post-harvest timber slash in Grande Ronde, Oregon were sampled using an instrument platform lofted into the plume using a tether-controlled aerostat or balloon. Emissions of carbon monoxide, carbon dioxide, methane, particulate matter (PM2.5 µm), black carbon, ultraviolet absorbing PM, elemental/organic carbon, semi-volatile organics (polycyclic aromatic hydrocarbons and polychlorinated dibenzodioxins/dibenzofurans), filter-based metals, and volatile organics were sampled for determination of emission factors. The effect on emissions from covering or not covering piles with polyethylene sheets to prevent fuel wetting was determined. Results showed that the uncovered (“wet”) piles burned with lower combustion efficiency and higher emissions of volatile organic compounds. Results for other pollutants will also be discussed. This work determined the emissions from open burning of forest slash wood, with and without plastic sheeting. The foresters advocate the use of plastic to keep the slash wood dry and aid in the controlled combustion of the slash to reduce fuel loading. Concerns about the emissions from the burning plastic prompted this work which conducted an extensive characterization of dry, wet, and dry with plastic slash pile emissions.

Preliminary Assessment Of The Burning Dynamics Of Jp8 Droplets In Microgravity

NASA Technical Reports Server (NTRS)

Bae, J. H.; Avedisian, C. T.

2003-01-01

In this report we present new data for fuel droplet combustion in microgravity to examine the influence of ambient gas and fuel composition on flame structure and sooting dynamics for droplets with initial diameters in the range of 0.4mm to 0.5mm. The fuels are JP8 (a kerosene derivative) and nonane. The ambient gas is air and a mixture of 30% oxygen and 70% helium, the latter having been examined for burning under conditions where soot formation is minimal. Some data at elevated pressures are also reported. The burning process shows a nonlinear D2 progression which is independent of soot formation as burning in a helium inert showed the same nonlinear trend. Flames were proportionally farther from the droplet surface in helium than they were in air. A nondimensional parameter is presented that consolidates the three standoff distances for the droplet, flame and soot shell diameters within the initial diameter ranges examined.

Comparing fuel reduction treatments for reducing wildfire size and intensity in a boreal forest landscape of northeastern China.

PubMed

Wu, Zhiwei; He, Hong S; Liu, Zhihua; Liang, Yu

2013-06-01

Fuel load is often used to prioritize stands for fuel reduction treatments. However, wildfire size and intensity are not only related to fuel loads but also to a wide range of other spatially related factors such as topography, weather and human activity. In prioritizing fuel reduction treatments, we propose using burn probability to account for the effects of spatially related factors that can affect wildfire size and intensity. Our burn probability incorporated fuel load, ignition probability, and spread probability (spatial controls to wildfire) at a particular location across a landscape. Our goal was to assess differences in reducing wildfire size and intensity using fuel-load and burn-probability based treatment prioritization approaches. Our study was conducted in a boreal forest in northeastern China. We derived a fuel load map from a stand map and a burn probability map based on historical fire records and potential wildfire spread pattern. The burn probability map was validated using historical records of burned patches. We then simulated 100 ignitions and six fuel reduction treatments to compare fire size and intensity under two approaches of fuel treatment prioritization. We calibrated and validated simulated wildfires against historical wildfire data. Our results showed that fuel reduction treatments based on burn probability were more effective at reducing simulated wildfire size, mean and maximum rate of spread, and mean fire intensity, but less effective at reducing maximum fire intensity across the burned landscape than treatments based on fuel load. Thus, contributions from both fuels and spatially related factors should be considered for each fuel reduction treatment. Published by Elsevier B.V.

Burning rates of wood cribs with implications for wildland fires

Treesearch

Sara McAllister; Mark Finney

2016-01-01

Wood cribs are often used as ignition sources for room fire tests and the well characterized burning rates may also have applications to wildland fires. The burning rate of wildland fuel structures, whether the needle layer on the ground or trees and shrubs themselves, is not addressed in any operational fire model and no simple model exists. Several relations...

PM2.5 pollution from household solid fuel burning practices in Central India: 2. Application of receptor models for source apportionment.

PubMed

Matawle, Jeevan Lal; Pervez, Shamsh; Deb, Manas Kanti; Shrivastava, Anjali; Tiwari, Suresh

2018-02-01

USEPA's UNMIX, positive matrix factorization (PMF) and effective variance-chemical mass balance (EV-CMB) receptor models were applied to chemically speciated profiles of 125 indoor PM 2.5 measurements, sampled longitudinally during 2012-2013 in low-income group households of Central India which uses solid fuels for cooking practices. Three step source apportionment studies were carried out to generate more confident source characterization. Firstly, UNMIX6.0 extracted initial number of source factors, which were used to execute PMF5.0 to extract source-factor profiles in second step. Finally, factor analog locally derived source profiles were supplemented to EV-CMB8.2 with indoor receptor PM 2.5 chemical profile to evaluate source contribution estimates (SCEs). The results of combined use of three receptor models clearly describe that UNMIX and PMF are useful tool to extract types of source categories within small receptor dataset and EV-CMB can pick those locally derived source profiles for source apportionment which are analog to PMF-extracted source categories. The source apportionment results have also shown three fold higher relative contribution of solid fuel burning emissions to indoor PM 2.5 compared to those measurements reported for normal households with LPG stoves. The previously reported influential source marker species were found to be comparatively similar to those extracted from PMF fingerprint plots. The comparison between PMF and CMB SCEs results were also found to be qualitatively similar. The performance fit measures of all three receptor models were cross-verified and validated and support each other to gain confidence in source apportionment results.

Design of a model to predict surge capacity bottlenecks for burn mass casualties at a large academic medical center.

PubMed

Abir, Mahshid; Davis, Matthew M; Sankar, Pratap; Wong, Andrew C; Wang, Stewart C

2013-02-01

To design and test a model to predict surge capacity bottlenecks at a large academic medical center in response to a mass-casualty incident (MCI) involving multiple burn victims. Using the simulation software ProModel, a model of patient flow and anticipated resource use, according to principles of disaster management, was developed based upon historical data from the University Hospital of the University of Michigan Health System. Model inputs included: (a) age and weight distribution for casualties, and distribution of size and depth of burns; (b) rate of arrival of casualties to the hospital, and triage to ward or critical care settings; (c) eligibility for early discharge of non-MCI inpatients at time of MCI; (d) baseline occupancy of intensive care unit (ICU), surgical step-down, and ward; (e) staff availability-number of physicians, nurses, and respiratory therapists, and the expected ratio of each group to patients; (f) floor and operating room resources-anticipating the need for mechanical ventilators, burn care and surgical resources, blood products, and intravenous fluids; (g) average hospital length of stay and mortality rate for patients with inhalation injury and different size burns; and (h) average number of times that different size burns undergo surgery. Key model outputs include time to bottleneck for each limiting resource and average waiting time to hospital bed availability. Given base-case model assumptions (including 100 mass casualties with an inter-arrival rate to the hospital of one patient every three minutes), hospital utilization is constrained within the first 120 minutes to 21 casualties, due to the limited number of beds. The first bottleneck is attributable to exhausting critical care beds, followed by floor beds. Given this limitation in number of patients, the temporal order of the ensuing bottlenecks is as follows: Lactated Ringer's solution (4 h), silver sulfadiazine/Silvadene (6 h), albumin (48 h), thrombin topical (72 h), type

Burning Velocity Measurements in Aluminum-Air Suspensions using Bunsen Type Dust Flames

NASA Technical Reports Server (NTRS)

Lee, John; Goroshin, Samuel; Kolbe, Massimiliano

2001-01-01

Laminar burning velocity (sometimes also referred in literature as fundamental or normal flame propagation speed) is probably the most important combustion characteristic of the premixed combustible mixture. The majority of experimental data on burning velocities in gaseous mixtures was obtained with the help of the Bunsen conical flame. The Bunsen cone method was found to be sufficiently accurate for gaseous mixtures with burning velocities higher than 10-15 cm/s at normal pressure. Hans Cassel was the first to demonstrate that suspensions of micron-size solid fuel particles in a gaseous oxidizer can also form self-sustained Bunsen flames. He was able to stabilize Bunsen flames in a number of suspensions of different nonvolatile solid fuels (aluminum, carbon, and boron). Using the Bunsen cone method he estimated burning velocities in the premixed aluminum-air mixtures (particle size less than 10 microns) to be in the range of 30-40 cm/s. Cassel also found, that the burning velocity in dust clouds is a function of the burner diameter. In our recent work, we have used the Bunsen cone method to investigate dependence of burning velocity on dust concentration in fuel-rich aluminum dust clouds. Burning velocities in stoichiometric and fuel-rich aluminum dust suspensions with average particle sizes of about 5 microns were found to be in the range of 20-25 cm/s and largely independent on dust concentration. These results raise the question to what degree burning velocities derived from Bunsen flame specifically and other dust flame configurations in general, are indeed fundamental characteristics of the mixture and to what degree are they apparatus dependent. Dust flames in comparison to gas combustion, are thicker, may be influenced by radiation heat transfer in the flame front, respond differently to heat losses, and are fundamentally influenced by the particular flow configuration due to the particles inertia. Since characteristic spatial scales of dust flames are

An Experimental Examination of Combustion of Isolated Liquid Fuel Droplets with Polymeric and Nanoparticle Additives

NASA Astrophysics Data System (ADS)

Ghamari, Mohsen

In spite of recent attention to renewable sources of energy, liquid hydrocarbon fuels are still the main source of energy for industrial and transportation systems. Manufactures and consumers are consistently looking for ways to optimize the efficiency of fuel combustion in terms of cost, emissions and consumer safety. In this regard, increasing burning rate of liquid fuels has been of special interest in both industrial and transportation systems. Recent studies have shown that adding combustible nano-particles could have promising effects on improving combustion performance of liquid fuels. Combustible nano-particles could enhance radiative and conductive heat transfer and also mixing within the droplet. Polymeric additive have also shown promising effect on improving fire safety by suppressing spreading behavior and splatter formation in case of crash scenario. Polymers are also known to have higher burning rate than regular hydrocarbon fuels. Therefore adding polymeric additive could have the potential to increase the burning rate. In this work, combustion dynamics of liquid fuel droplets with both polymeric and nanoparticle additives is studied in normal gravity. High speed photography is employed and the effect of additive concentration on droplet burning rate, burning time, extinction and soot morphology is investigated. Polymer added fuel was found to have a volatility controlled combustion with four distinct regimes. The first three zones are associated with combustion of base fuel while the polymer burns last and after a heating zone because of its higher boiling point. Polymer addition reduces the burning rate of the base fuel in the first zone by means of increasing viscosity and results in nucleate boiling and increased burning rates in the second and third stages. Overall, polymer addition resulted in a higher burning rate and shorter burning time in most of the scenarios. Colloidal suspensions of carbon-based nanomaterials in liquid fuels were also

Molecular Characterization of Brown Carbon in Biomass Burning Aerosol Particles.

PubMed

Lin, Peng; Aiona, Paige K; Li, Ying; Shiraiwa, Manabu; Laskin, Julia; Nizkorodov, Sergey A; Laskin, Alexander

2016-11-01

Emissions from biomass burning are a significant source of brown carbon (BrC) in the atmosphere. In this study, we investigate the molecular composition of freshly emitted biomass burning organic aerosol (BBOA) samples collected during test burns of sawgrass, peat, ponderosa pine, and black spruce. We demonstrate that both the BrC absorption and the chemical composition of light-absorbing compounds depend significantly on the type of biomass fuels. Common BrC chromophores in the selected BBOA samples include nitro-aromatics, polycyclic aromatic hydrocarbon derivatives, and polyphenols spanning a wide range of molecular weights, structures, and light absorption properties. A number of biofuel-specific BrC chromophores are observed, indicating that some of them may be used as source-specific markers of BrC. On average, ∼50% of the light absorption in the solvent-extractable fraction of BBOA can be attributed to a limited number of strong BrC chromophores. The absorption coefficients of BBOA are affected by solar photolysis. Specifically, under typical atmospheric conditions, the 300 nm absorbance decays with a half-life of ∼16 h. A "molecular corridor" analysis of the BBOA volatility distribution suggests that many BrC compounds in the fresh BBOA have low saturation mass concentration (<1 μg m -3 ) and will be retained in the particle phase under atmospherically relevant conditions.

Light-absorbing organic carbon from prescribed and laboratory biomass burning and gasoline vehicle emissions.

PubMed

Xie, Mingjie; Hays, Michael D; Holder, Amara L

2017-08-04

Light-absorbing organic carbon (OC), also termed brown carbon (BrC), from laboratory-based biomass burning (BB) has been studied intensively to understand the contribution of BB to radiative forcing. However, relatively few measurements have been conducted on field-based BB and even fewer measurements have examined BrC from anthropogenic combustion sources like motor vehicle emissions. In this work, the light absorption of methanol-extractable OC from prescribed and laboratory BB and gasoline vehicle emissions was examined using spectrophotometry. The light absorption of methanol extracts showed a strong wavelength dependence for both BB and gasoline vehicle emissions. The mass absorption coefficients at 365 nm (MAC 365 , m 2 g -1 C) - used as a measurement proxy for BrC - were significantly correlated (p < 0.05) to the elemental carbon (EC)/OC ratios when examined by each BB fuel type. No significant correlation was observed when pooling fuels, indicating that both burn conditions and fuel types may impact BB BrC characteristics. The average MAC 365 of gasoline vehicle emission samples is 0.62 ± 0.76 m 2  g -1 C, which is similar in magnitude to the BB samples (1.27 ± 0.76 m 2  g -1 C). These results suggest that in addition to BB, gasoline vehicle emissions may also be an important BrC source in urban areas.

Hydrogen and helium shell burning during white dwarf accretion

NASA Astrophysics Data System (ADS)

Cui, Xiao; Meng, Xiang-Cun; Han, Zhan-Wen

2018-05-01

Type Ia supernovae (SNe Ia) are believed to be thermonuclear explosions of carbon oxygen (CO) white dwarfs (WDs) with masses close to the Chandrasekhar mass limit. How a CO WD accretes matter and grows in mass to this limit is not well understood, hindering our understanding of SN Ia explosions and the reliability of using SNe Ia as a cosmological distance indicator. In this work, we employed the stellar evolution code MESA to simulate the accretion process of hydrogen-rich material onto a 1.0 M ⊙ CO WD at a high rate (over the Eddington limit) of 4.3 × 10‑7 M ⊙ yr‑1. The simulation demonstrates the characteristics of the double shell burning on top of the WD, with a hydrogen shell burning on top of a helium burning shell. The results show that helium shell burning is not steady (i.e. it flashes). Flashes from the helium shell are weaker than those in the case of accretion of helium-rich material onto a CO WD. The carbon to oxygen mass ratio resulting from the helium shell burning is higher than what was previously thought. Interestingly, the CO WD growing due to accretion has an outer part containing a small fraction of helium in addition to carbon and oxygen. The flashes become weaker and weaker as the accretion continues.

Epidemiology of U.K. Military Burns 2008-2013.

PubMed

Page, Felicity; Hamnett, Nathan; D'Asta, Federica; Jeffery, Steven

After sustaining burn injuries overseas, U.K. Armed Forces personnel are evacuated to the Royal Centre for Defence Medicine. The objective was to review the etiology of U.K. Military burns managed at the center between 2008 and 2013. Analysis will aid provision planning and assist in the prevention of burn injuries for future tours. The International Burn Injury Database database of all U.K. Armed Forces burn injured patients evacuated to the Queen Elizabeth University Hospital Birmingham between 2008 and 2013 were reviewed retrospectively. Analysis included patient demographics, injury mechanism, burn severity, management, and mortality. There were 65 military personnel with burn injuries requiring repatriation to the United Kingdom. Percentage of 78.5 were sustained in Afghanistan. The mean age was 25 (18-46) years. Percentage of 70.8 were considered noncombat burn injuries. Of the noncombat burns, the mechanism of injury most commonly involved burning waste and misuse of fuels and scalds. The mean TBSA for all patients was 6% (0.05-51%). Areas most commonly affected included arms, legs, and face. The length of hospital stay for combat vs noncombat burn injury patients was 10 vs 7 days. There were no fatalities. In conclusion, substantially fewer military personnel sustained combat burns between 2008 and 2013 than in preceding study period (19 vs 79). The number of accidental noncombat burns remained constant. The decrease in combat burns may reflect a relative decrease in military intensity and effective protective equipment and safety measures. Further education may allow for an additional decrease in preventable burn injuries.

Trace gas and particle emissions from domestic and industrial biofuel use and garbage burning in central Mexico

NASA Astrophysics Data System (ADS)

Christian, T. J.; Yokelson, R. J.; Cárdenas, B.; Molina, L. T.; Engling, G.; Hsu, S.-C.

2009-04-01

In central Mexico during the spring of 2007 we measured the initial emissions of 12 gases and the aerosol speciation for elemental and organic carbon (EC, OC), anhydrosugars, Cl-, NO3-, and 20 metals from 10 cooking fires, four garbage fires, three brick making kilns, three charcoal making kilns, and two crop residue fires. Biofuel use has been estimated at over 2600 Tg/y. With several simple case studies we show that cooking fires can be a major, or the major, source of several gases and fine particles in developing countries. Insulated cook stoves with chimneys were earlier shown to reduce indoor air pollution and the fuel use per cooking task. We confirm that they also reduce the emissions of VOC pollutants per mass of fuel burned by about half. We did not detect HCN emissions from cooking fires in Mexico or Africa. Thus, if regional source attribution is based on HCN emissions typical for other types of biomass burning (BB), then biofuel use and total BB will be underestimated in much of the developing world. This is also significant because cooking fires are not detected from space. We estimate that 2000 Tg/y of garbage are generated and about half may be burned, making this a commonly overlooked major global source of emissions. We estimate a fine particle emission factor (EFPM2.5 for garbage burning of ~10±5 g/kg, which is in reasonable agreement with very limited previous work. We observe large HCl emission factors in the range 2-10 g/kg. Consideration of the Cl content of the global waste stream suggests that garbage burning may generate as much as 6-9 Tg/yr of HCl, which would make it a major source of this compound. HCl generated by garbage burning in dry environments may have a relatively greater atmospheric impact than HCl generated in humid areas. Garbage burning PM2.5 was found to contain levoglucosan and K in concentrations similar to those for biomass burning, so it could be a source of interference in some areas when using these tracers to

Nuclear system that burns its own wastes shows promise

NASA Technical Reports Server (NTRS)

Atchison, K.

1975-01-01

A nuclear fission energy system, capable of eliminating a significant amount of its radioactive wastes by burning them, is described. A theoretical investigation of this system conducted by computer analysis, is based on use of gaseous fuel nuclear reactors. Gaseous core reactors using a uranium plasma fuel are studied along with development for space propulsion.

Fuel processor for fuel cell power system

DOEpatents

Vanderborgh, Nicholas E.; Springer, Thomas E.; Huff, James R.

1987-01-01

A catalytic organic fuel processing apparatus, which can be used in a fuel cell power system, contains within a housing a catalyst chamber, a variable speed fan, and a combustion chamber. Vaporized organic fuel is circulated by the fan past the combustion chamber with which it is in indirect heat exchange relationship. The heated vaporized organic fuel enters a catalyst bed where it is converted into a desired product such as hydrogen needed to power the fuel cell. During periods of high demand, air is injected upstream of the combustion chamber and organic fuel injection means to burn with some of the organic fuel on the outside of the combustion chamber, and thus be in direct heat exchange relation with the organic fuel going into the catalyst bed.

Thermal conductivity of fresh and irradiated U-Mo fuels

NASA Astrophysics Data System (ADS)

Huber, Tanja K.; Breitkreutz, Harald; Burkes, Douglas E.; Casella, Amanda J.; Casella, Andrew M.; Elgeti, Stefan; Reiter, Christian; Robinson, Adam. B.; Smith, Frances. N.; Wachs, Daniel. M.; Petry, Winfried

2018-05-01

The thermal conductivity of fresh and irradiated U-Mo dispersion and monolithic fuel has been investigated experimentally and compared to theoretical models. During in-pile irradiation, thermal conductivity of fresh dispersion fuel at a temperature of 150 °C decreased from 59 W/m·K to 18 W/m·K at a burn-up of 4.9·1021 f/cc and further to 9 W/m·K at a burn-up of 6.1·1021 f/cc. Fresh monolithic fuel has a considerably lower thermal conductivity of 15 W/m·K at a temperature of 150 °C and consequently its decrease during in-pile irradiation is less steep than for dispersion fuel. For a burn-up of 3.5·1021 f/cc of monolithic fuel, a thermal conductivity of 11 W/m·K at a temperature of 150 °C has been measured by Burkes et al. (2015). The difference of decrease for both fuels originates from effects in the matrix that occur during irradiation, like for dispersion fuel the gradual disappearance of the Al matrix with increased burn-up and the subsequent growth of an interaction layer (IDL) between the U-Mo fuel particle and Al matrix and subsequent matrix hardening. The growth of fission gas bubbles and the decomposition of the U-Mo crystal lattice also affect both dispersion and monolithic fuel.

Thermal conductivity of fresh and irradiated U-Mo fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huber, Tanja K.; Breitkreutz, Harald; Burkes, Douglas E.

The thermal conductivity of fresh and irradiated U-Mo dispersion and monolithic fuel has been investigated experimentally and compared to theoretical models. During in-pile irradiation, the thermal conductivity of fresh dispersion fuel at a temperature of 150°C decreases from 59 W/m ·K down to 18  W/m ·K at a burn-up of 4.9 ·10 21 f/cc and further down to 9 W/m·K at a burn-up of 6.1·10 21 f/cc. Fresh monolithic fuel has a considerably lower thermal conductivity of 15 W/m·K at a temperature of 150 °C and consequently its decrease during in-pile irradiation is less steep as for the dispersion fuel. For a burn-up ofmore » 3.5·10 21 f /cc of monolithic fuel 11 W/m·K at a temperature of 150 °C has been measured by Burkes et al. The difference of the decrease of both fuels originates from effects in the matrix that occur during irradiation, like for dispersion fuel the gradual disappearance of the Al matrix with increasing burn-up and the subsequent growth of an interaction layer (IDL) between the U-Mo fuel particle and Al matrix and subsequent matrix hardening. The growth of fission gas bubbles and the decomposition of the U-Mo crystal lattice affects both dispersion and monolithic fuel.« less

Resonance Ionization Mass Spectrometry System for Measurement of Environmental Samples

NASA Astrophysics Data System (ADS)

Pibida, L.; McMahon, C. A.; Nörtershäuser, W.; Bushaw, B. A.

2002-10-01

A resonance ionization mass spectrometry (RIMS) system has been developed at the National Institute of Standards and Technology (NIST) for sensitive and selective determination of radio-cesium in the environment. The overall efficiency was determined to be 4×10-7 with a combined (laser and mass spectrometer) selectivity of 108 for both 135Cs and 137Cs with respect to 133Cs. RIMS isotopic ratio measurements of 135Cs/ 137Cs were performed on a nuclear fuel burn-up sample and compared to measurements on a similar system at Pacific Northwest National Laboratory (PNNL) and to conventional thermal ionization mass spectrometry (TIMS). Results of preliminary RIMS investigations on a freshwater lake sediment sample are also discussed.

Prescribed burning in the interior ponderosa pine type of northeastern California . . . a preliminary study

Treesearch

Donald T. Gordon

1967-01-01

Three prescribed burns, made in 1959-62, in the interior ponderosa pine type of northeastern California are described in terms of meteorological factors, fire behavior, and effects of burning. Results were generally unsatisfactory. Factors that limit the usefulness of prescribed burning for reducing fuel hazard or for thinning in young-growth stands include stand...

Mass spectrometric analysis and aerodynamic properties of various types of combustion-related aerosol particles

NASA Astrophysics Data System (ADS)

Schneider, J.; Weimer, S.; Drewnick, F.; Borrmann, S.; Helas, G.; Gwaze, P.; Schmid, O.; Andreae, M. O.; Kirchner, U.

2006-12-01

Various types of combustion-related particles in the size range between 100 and 850 nm were analyzed with an aerosol mass spectrometer and a differential mobility analyzer. The measurements were performed with particles originating from biomass burning, diesel engine exhaust, laboratory combustion of diesel fuel and gasoline, as well as from spark soot generation. Physical and morphological parameters like fractal dimension, effective density, bulk density and dynamic shape factor were derived or at least approximated from the measurements of electrical mobility diameter and vacuum aerodynamic diameter. The relative intensities of the mass peaks in the mass spectra obtained from particles generated by a commercial diesel passenger car, by diesel combustion in a laboratory burner, and by evaporating and re-condensing lubrication oil were found to be very similar. The mass spectra from biomass burning particles show signatures identified as organic compounds like levoglucosan but also others which are yet unidentified. The aerodynamic behavior yielded a fractal dimension (Df) of 2.09 +/- 0.06 for biomass burning particles from the combustion of dry beech sticks, but showed values around three, and hence more compact particle morphologies, for particles from combustion of more natural oak. Scanning electron microscope images confirmed the finding that the beech combustion particles were fractal-like aggregates, while the oak combustion particles displayed a much more compact shape. For particles from laboratory combusted diesel fuel, a Df value of 2.35 was found, for spark soot particles, Df [approximate] 2.10. The aerodynamic properties of fractal-like particles from dry beech wood combustion indicate an aerodynamic shape factor [chi] that increases with electrical mobility diameter, and a bulk density of 1.92 g cm-3. An upper limit of [chi] [approximate] 1.2 was inferred for the shape factor of the more compact particles from oak combustion.

OH-initiated Aging of Biomass Burning Aerosol during FIREX

NASA Astrophysics Data System (ADS)

Lim, C. Y.; Hagan, D. H.; Cappa, C. D.; Kroll, J. H.; Coggon, M.; Koss, A.; Sekimoto, K.; De Gouw, J. A.; Warneke, C.

2017-12-01

Biomass burning emissions represent a major source of fine particulate matter to the atmosphere, and this source will likely become increasingly important in the future due to changes in the Earth's climate. Understanding the effects that increased fire emissions have on both air quality and climate requires understanding the composition of the particles emitted, since chemical and physical composition directly impact important particle properties such as absorptivity, toxicity, and cloud condensation nuclei activity. However, the composition of biomass burning particles in the atmosphere is dynamic, as the particles are subject to the condensation of low-volatility vapors and reaction with oxidants such as the hydroxyl radical (OH) during transport. Here we present a series of laboratory chamber experiments on the OH-initiated aging of biomass burning aerosol performed at the Fire Sciences Laboratory in Missoula, MT as part of the Fire Influences on Regional and Global Environments Experiment (FIREX) campaign. We describe the evolution of biomass burning aerosol produced from a variety of fuels operating the chamber in both particle-only and gas + particle mode, focusing on changes to the organic composition. In particle-only mode, gas-phase biomass burning emissions are removed before oxidation to focus on heterogeneous oxidation, while gas + particle mode includes both heterogeneous oxidation and condensation of oxidized volatile organic compounds onto the particles (secondary organic aerosol formation). Variability in fuels and burning conditions lead to differences in aerosol loading and secondary aerosol production, but in all cases aging results in a significant and rapid increases in the carbon oxidation state of the particles.

Goal-Directed Fluid Resuscitation Protocol Based on Arterial Waveform Analysis of Major Burn Patients in a Mass Burn Casualty.

PubMed

Chiao, Hao-Yu; Chou, Chang-Yi; Tzeng, Yuan-Sheng; Wang, Chih-Hsin; Chen, Shyi-Gen; Dai, Niann-Tzyy

2018-02-01

Adequate fluid titration during the initial resuscitation period of major burn patients is crucial. This study aimed to evaluate the feasibility and efficacy of a goal-directed fluid resuscitation protocol that used hourly urine output plus the arterial waveform analysis FloTrac (Edwards LifeSciences, Irvine, Calif) system for major burns to avoid fluid overload. We conducted a retrospective cohort study of 43 major burn patients at the Tri-Service General Hospital after the Formosa Fun Coast Dust Explosion on June 27, 2015. Because of the limited capacity of intensive care units (ICUs), 23 intubated patients were transferred from the burn wards or emergency department to the ICU within 24 hours. Fluid administration was adjusted to achieve a urine output of 30 to 50 mL/h, cardiac index greater than 2.5 L/min/m, and stroke volume variation (SVV) less than 12%. The hourly crystalloid fluid infusion rate was titrated based on SVV and hourly urine output. Of the 23 critically burned patients admitted to the ICU, 13 patients who followed the goal-directed fluid resuscitation protocol within 12 hours postburn were included in the analysis. The mean age (years) was 21.8, and the mean total body surface area (TBSA) burned (%) was 68.0. The mean Revised Baux score was 106.8. All patients sustained inhalation injury. The fluid volumes administered to patients in the first 24 hours and the second 24 hours (mL/kg/% total body surface area) were 3.62 ± 1.23 and 2.89 ± 0.79, respectively. The urine outputs in the first 24 hours and the second 24 hours (mL/kg/h) were 1.13 ± 0.66 and 1.53 ± 0.87, respectively. All patients achieved the established goals within 32 hours postburn. In-hospital mortality rate was 0%. The SVV-based goal-directed fluid resuscitation protocol leads to less unnecessary fluid administration during the early resuscitation phase. Clinicians can efficaciously manage the dynamic body fluid changes in major burn patients under the guidance of the protocol.

High regression rate hybrid rocket fuel grains with helical port structures

NASA Astrophysics Data System (ADS)

Walker, Sean D.

Hybrid rockets are popular in the aerospace industry due to their storage safety, simplicity, and controllability during rocket motor burn. However, they produce fuel regression rates typically 25% lower than solid fuel motors of the same thrust level. These lowered regression rates produce unacceptably high oxidizer-to-fuel (O/F) ratios that produce a potential for motor instability, nozzle erosion, and reduced motor duty cycles. To achieve O/F ratios that produce acceptable combustion characteristics, traditional cylindrical fuel ports are fabricated with very long length-to-diameter ratios to increase the total burning area. These high aspect ratios produce further reduced fuel regression rate and thrust levels, poor volumetric efficiency, and a potential for lateral structural loading issues during high thrust burns. In place of traditional cylindrical fuel ports, it is proposed that by researching the effects of centrifugal flow patterns introduced by embedded helical fuel port structures, a significant increase in fuel regression rates can be observed. The benefits of increasing volumetric efficiencies by lengthening the internal flow path will also be observed. The mechanisms of this increased fuel regression rate are driven by enhancing surface skin friction and reducing the effect of boundary layer "blowing" to enhance convective heat transfer to the fuel surface. Preliminary results using additive manufacturing to fabricate hybrid rocket fuel grains from acrylonitrile-butadiene-styrene (ABS) with embedded helical fuel port structures have been obtained, with burn-rate amplifications up to 3.0x than that of cylindrical fuel ports.

40 CFR 60.4325 - What emission limits must I meet for NOX if my turbine burns both natural gas and distillate oil...

Code of Federal Regulations, 2012 CFR

2012-07-01

... NOX if my turbine burns both natural gas and distillate oil (or some other combination of fuels)? 60... Combustion Turbines Emission Limits § 60.4325 What emission limits must I meet for NOX if my turbine burns... burning that fuel. Similarly, when your total heat input is greater than 50 percent distillate oil and...

40 CFR 60.4325 - What emission limits must I meet for NOX if my turbine burns both natural gas and distillate oil...

Code of Federal Regulations, 2014 CFR

2014-07-01

... NOX if my turbine burns both natural gas and distillate oil (or some other combination of fuels)? 60... Combustion Turbines Emission Limits § 60.4325 What emission limits must I meet for NOX if my turbine burns... burning that fuel. Similarly, when your total heat input is greater than 50 percent distillate oil and...

40 CFR 60.4325 - What emission limits must I meet for NOX if my turbine burns both natural gas and distillate oil...

Code of Federal Regulations, 2013 CFR

2013-07-01

... NOX if my turbine burns both natural gas and distillate oil (or some other combination of fuels)? 60... Combustion Turbines Emission Limits § 60.4325 What emission limits must I meet for NOX if my turbine burns... burning that fuel. Similarly, when your total heat input is greater than 50 percent distillate oil and...

Impact of Alternative Jet Fuels on Engine Exhaust Composition During the 2015 ECLIF Ground-Based Measurements Campaign.

PubMed

Schripp, Tobias; Anderson, Bruce; Crosbie, Ewan C; Moore, Richard H; Herrmann, Friederike; Oßwald, Patrick; Wahl, Claus; Kapernaum, Manfred; Köhler, Markus; Le Clercq, Patrick; Rauch, Bastian; Eichler, Philipp; Mikoviny, Tomas; Wisthaler, Armin

2018-04-17

The application of fuels from renewable sources ("alternative fuels") in aviation is important for the reduction of anthropogenic carbon dioxide emissions, but may also attribute to reduced release of particles from jet engines. The present experiment describes ground-based measurements in the framework of the ECLIF (Emission and Climate Impact of Alternative Fuels) campaign using an Airbus A320 (V2527-A5 engines) burning six fuels of chemically different composition. Two reference Jet A-1 with slightly different chemical parameters were applied and further used in combination with a Fischer-Tropsch synthetic paraffinic kerosene (FT-SPK) to prepare three semi synthetic jet fuels (SSJF) of different aromatic content. In addition, one commercially available fully synthetic jet fuel (FSJF) featured the lowest aromatic content of the fuel selection. Neither the release of nitrogen oxide or carbon monoxide was significantly affected by the different fuel composition. The measured particle emission indices showed a reduction up to 50% (number) and 70% (mass) for two alternative jet fuels (FSJF, SSJF2) at low power settings in comparison to the reference fuels. The reduction is less pronounced at higher operating conditions but the release of particle number and particle mass is still significantly lower for the alternative fuels than for both reference fuels. The observed correlation between emitted particle mass and fuel aromatics is not strict. Here, the H/C ratio is a better indicator for soot emission.

Rehabilitating slash pile burn scars in upper montane forests of the Colorado Front Range

Treesearch

Paula J. Fornwalt; Charles C. Rhoades

2011-01-01

Slash pile burning is widely conducted by land managers to dispose of unwanted woody fuels, yet this practice typically has undesirable ecological impacts. Simple rehabilitation treatments may be effective at ameliorating some of the negative impacts of pile burning on plants and soils. Here, we investigated: (1) the impacts of slash pile burning on soil nitrogen and...

Further observations on OCOM MOX fuel: microstructure in the vicinity of the pellet rim and fuel — cladding interaction

NASA Astrophysics Data System (ADS)

Walker, C. T.; Goll, W.; Matsumura, T.

1997-06-01

The fuel investigated was manufactured by Siemens-KWU and irradiated at low rating in the KWO reactor in Germany. The MOX agglomerates in the cold outer region of the fuel shared several common features with the high burn-up structure at the rim of UO 2 fuel. It is proposed that in both cases the mechanism producing the microstructure change is recrystallisation. Further, it is shown that surface MOX agglomerates do not noticeably retard cladding creepdown although they swell into the gap. The contracting cladding appears able to push the agglomerates back into the fuel. The thickness of the oxide layer on the inner cladding surface increased at points where contact with surface MOX agglomerates had occurred. Despite this, the mean thickness of the oxide did not differ significantly from that found in UO 2 fuel rods of like design. It is judged that the high burn-up structure will form in the UO 2 matrix when the local burn-up there reaches 60 to 80 GWd/tM. Limiting the MOX scrap addition in the UO 2 matrix will delay its formation.

Evaluating spatially explicit burn probabilities for strategic fire management planning

Treesearch

C. Miller; M.-A. Parisien; A. A. Ager; M. A. Finney

2008-01-01

Spatially explicit information on the probability of burning is necessary for virtually all strategic fire and fuels management planning activities, including conducting wildland fire risk assessments, optimizing fuel treatments, and prevention planning. Predictive models providing a reliable estimate of the annual likelihood of fire at each point on the landscape have...

Near Surface Vapor Bubble Layers in Buoyant Low Stretch Burning of Polymethylmethacrylate

NASA Technical Reports Server (NTRS)

Olson, Sandra L.; Tien, J. S.

1999-01-01

Large-scale buoyant low stretch stagnation point diffusion flames over solid fuel (polymethylmethacrylate) were studied for a range of aerodynamic stretch rates of 2-12/ sec which are of the same order as spacecraft ventilation-induced stretch in a microgravity environment. An extensive layer of polymer material above the glass transition temperature is observed. Unique phenomena associated with this extensive glass layer included substantial swelling of the burning surface, in-depth bubble formation, and migration and/or elongation of the bubbles normal to the hot surface. The bubble layer acted to insulate the polymer surface by reducing the effective conductivity of the solid. The reduced in-depth conduction stabilized the flame for longer than expected from theory neglecting the bubble layer. While buoyancy acts to move the bubbles deeper into the molten polymer, thermocapillary forces and surface regression both act to bring the bubbles to the burning surface. Bubble layers may thus be very important in low gravity (low stretch) burning of materials. As bubbles reached the burning surface, monomer fuel vapors jetted from the surface, enhancing burning by entraining ambient air flow. Popping of these bubbles at the surface can expel burning droplets of the molten material, which may increase the fire propagation hazards at low stretch rates.

NASA Lewis Research Center lean-, rich-burn materials test burner rig

NASA Technical Reports Server (NTRS)

Stearns, C. A.; Robinson, R. C.

1994-01-01

The lean-, rich-burn materials test burner rig at NASA LeRC is used to evaluate the high temperature environmental durability of aerospace materials. The rig burns jet fuel and pressurized air, and sample materials can be subjected to both lean-burn and rich-burn environments. As part of NASA's Enabling Propulsion Materials (EPM) program, an existing rig was adapted to simulate the rich-burn quick-quench lean-burn (RQL) combustor concept which is being considered for the HSCT (high speed civil transport) aircraft. RQL materials requirements exceed that of current superalloys, thus ceramic matrix composites (CMC's) emerged as the leading candidate materials. The performance of these materials in the quasi reducing environment of the rich-burn section of the RQL is of fundamental importance to materials development. This rig was developed to conduct such studies, and its operation and capabilities are described.

FEASIBILITY OF BURNING COAL IN CATALYTIC COMBUSTORS

EPA Science Inventory

The report gives results of a study, showing that pulverized coal can be burned in a catalytic combustor. Pulverized coal combustion in catalytic beds is markedly different from gaseous fuel combustion. Gas combustion gives uniform bed temperatures and reaction rates over the ent...

Aluminum Hydride as a Fuel Supplement to NanoThermites

DTIC Science & Technology

2014-01-01

nanocomposite thermite based on CuO, Bi2O3, and Fe2O3. Pressure cell and burn tube experiments demonstrated enhancements in absolute pressure...pressurization rate, and burning velocity when micron-scale aluminum hydride was used as a minor fuel component in a nanoaluminum–copper-oxide thermite ...alane, AlH3) replaced nanoaluminum incrementally as a fuel in a nanocomposite thermite based on CuO, Bi2O3, and Fe2O3. Pressure cell and burn tube

Converting small industrial boilers to burn wood fuels

Treesearch

Raymond L. Sarles; J. Penn Rutherfoord

1982-01-01

Investigates the engineering and economic feasibility of retrofitting two small industrial boilers (32 hp and 52 hp, respectively) for firing green wood fuels. Subjects covered include fuel requirements and costs; availability, storage, and handling of wood fuels; and designs, specifications, stack emissions, cost estimates, and economic feasibility. The economics of...

The effects of prescribed burning on fire hazard in the chaparral: toward a new conceptual synthesis

Treesearch

Anthony T. Dunn

1989-01-01

Prescribed burning for fire hazard reduction in the chaparral is predicated on the belief that young fuels (20 years old and less) are highly resistant to burning. To test this belief, a data base search of large fires in San Diego County between 1940 and 1985 was conducted to locate reburns of young chaparral fuels greater than 1000 acres (400 ha) in extent. Of the...

Stable Carbon Fractionation In Size Segregated Aerosol Particles Produced By Controlled Biomass Burning

NASA Astrophysics Data System (ADS)

Masalaite, Agne; Garbaras, Andrius; Garbariene, Inga; Ceburnis, Darius; Martuzevicius, Dainius; Puida, Egidijus; Kvietkus, Kestutis; Remeikis, Vidmantas

2014-05-01

Biomass burning is the largest source of primary fine fraction carbonaceous particles and the second largest source of trace gases in the global atmosphere with a strong effect not only on the regional scale but also in areas distant from the source . Many studies have often assumed no significant carbon isotope fractionation occurring between black carbon and the original vegetation during combustion. However, other studies suggested that stable carbon isotope ratios of char or BC may not reliably reflect carbon isotopic signatures of the source vegetation. Overall, the apparently conflicting results throughout the literature regarding the observed fractionation suggest that combustion conditions may be responsible for the observed effects. The purpose of the present study was to gather more quantitative information on carbonaceous aerosols produced in controlled biomass burning, thereby having a potential impact on interpreting ambient atmospheric observations. Seven different biomass fuel types were burned under controlled conditions to determine the effect of the biomass type on the emitted particulate matter mass and stable carbon isotope composition of bulk and size segregated particles. Size segregated aerosol particles were collected using the total suspended particle (TSP) sampler and a micro-orifice uniform deposit impactor (MOUDI). The results demonstrated that particle emissions were dominated by the submicron particles in all biomass types. However, significant differences in emissions of submicron particles and their dominant sizes were found between different biomass fuels. The largest negative fractionation was obtained for the wood pellet fuel type while the largest positive isotopic fractionation was observed during the buckwheat shells combustion. The carbon isotope composition of MOUDI samples compared very well with isotope composition of TSP samples indicating consistency of the results. The measurements of the stable carbon isotope ratio in

Alternative Fuel for Portland Cement Processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schindler, Anton K; Duke, Steve R; Burch, Thomas E

2012-06-30

The production of cement involves a combination of numerous raw materials, strictly monitored system processes, and temperatures on the order of 1500 °C. Immense quantities of fuel are required for the production of cement. Traditionally, energy from fossil fuels was solely relied upon for the production of cement. The overarching project objective is to evaluate the use of alternative fuels to lessen the dependence on non-renewable resources to produce portland cement. The key objective of using alternative fuels is to continue to produce high-quality cement while decreasing the use of non-renewable fuels and minimizing the impact on the environment. Burnmore » characteristics and thermodynamic parameters were evaluated with a laboratory burn simulator under conditions that mimic those in the preheater where the fuels are brought into a cement plant. A drop-tube furnace and visualization method were developed that show potential for evaluating time- and space-resolved temperature distributions for fuel solid particles and liquid droplets undergoing combustion in various combustion atmospheres. Downdraft gasification has been explored as a means to extract chemical energy from poultry litter while limiting the throughput of potentially deleterious components with regards to use in firing a cement kiln. Results have shown that the clinkering is temperature independent, at least within the controllable temperature range. Limestone also had only a slight effect on the fusion when used to coat the pellets. However, limestone addition did display some promise in regards to chlorine capture, as ash analyses showed chlorine concentrations of more than four times greater in the limestone infused ash as compared to raw poultry litter. A reliable and convenient sampling procedure was developed to estimate the combustion quality of broiler litter that is the best compromise between convenience and reliability by means of statistical analysis. Multi-day trial burns were

The combustion of large particles of char in bubbling fluidized beds: The dependence of Sherwood number and the rate of burning on particle diameter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dennis, J.S.; Hayhurst, A.N.; Scott, S.A.

Particles of char derived from a variety of fuels (e.g., biomass, sewage sludge, coal, or graphite), with diameters in excess of {approx}1.5mm, burn in fluidized bed combustors containing smaller particles of, e.g., sand, such that the rate is controlled by the diffusion both of O{sub 2} to the burning solid and of the products CO and CO{sub 2} away from it into the particulate phase. It is therefore important to characterize these mass transfer processes accurately. Measurements of the burning rate of char particles made from sewage sludge suggest that the Sherwood number, Sh, increases linearly with the diameter ofmore » the fuel particle, d{sub char} (for d{sub char}>{approx}1.5mm). This linear dependence of Sh on d{sub char} is expected from the basic equation Sh=2{epsilon}{sub mf}(1+d{sub char}/2{delta}{sub diff})/{tau}, provided the thickness of the boundary layer for mass transfer, {delta}{sub diff}, is constant in the region of interest (d{sub char}>{approx}1.5mm). Such a dependence is not seen in the empirical equations currently used and based on the Frossling expression. It is found here that for chars made from sewage sludge (for d{sub char}>{approx}1.5mm), the thickness of the boundary layer for mass transfer in a fluidized bed, {delta}{sub diff}, is less than that predicted by empirical correlations based on the Frossling expression. In fact, {delta}{sub diff} is not more than the diameter of the fluidized sand particles. Finally, the experiments in this study indicate that models based on surface renewal theory should be rejected for a fluidized bed, because they give unrealistically short contact times for packets of fluidized particles at the surface of a burning sphere. The result is the new correlation Sh = 2{epsilon}{sub mf}/{tau} + (A{sub cush}/A{sub char})(d{sub char}/ {delta}{sub diff}) for the dependence of Sh on d{sub char}, the diameter of a burning char particle. This equation is based on there being a gas-cushion of fluidizing gas

Fuel-rich catalytic combustion of Jet-A fuel-equivalence ratios 5.0 to 8.0

NASA Technical Reports Server (NTRS)

Brabbs, Theodore A.; Gracia-Salcedo, Carmen M.

1989-01-01

Fuel-rich catalytic combustion (E.R. greater than 5.0) is a unique technique for preheating a hydrocarbon fuel to temperatures much higher than those obtained by conventional heat exchangers. In addition to producing very reactive molecules, the process upgrades the structure of the fuel by the formation of hydrogen and smaller hydrocarbons and produces a cleaner burning fuel by removing some of the fuel carbon from the soot formation chain. With fuel-rich catalytic combustion as the first stage of a two stage combustion system, enhanced fuel properties can be utilized by both high speed engines, where time for ignition and complete combustion is limited, and engines where emission of thermal NO sub x is critical. Two-stage combustion (rich-lean) has been shown to be effective for NO sub x reduction in stationary burners where residence times are long enough to burn-up the soot formed in the first stage. Such residence times are not available in aircraft engines. Thus, the soot-free nature of the present process is critical for high speed engines. The successful application of fuel-rich catalytic combustion to Jet-A, a multicomponent fuel used in gas turbine combustors, is discusssed.