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1

Air Pollution Control Regulations: No. 5 - Fugitive Dust (Rhode Island) |  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

5 - Fugitive Dust (Rhode 5 - Fugitive Dust (Rhode Island) Air Pollution Control Regulations: No. 5 - Fugitive Dust (Rhode Island) < Back Eligibility Agricultural Commercial Construction Fed. Government Fuel Distributor General Public/Consumer Industrial Installer/Contractor Institutional Investor-Owned Utility Local Government Low-Income Residential Multi-Family Residential Municipal/Public Utility Nonprofit Residential Retail Supplier Rural Electric Cooperative Schools State/Provincial Govt Systems Integrator Transportation Tribal Government Utility Savings Category Alternative Fuel Vehicles Hydrogen & Fuel Cells Buying & Making Electricity Water Home Weatherization Wind Program Info State Rhode Island Program Type Environmental Regulations Provider Department of Environmental Management These regulations aim to prevent the release of fugitive dust by forbidding

2

Capturing Fugitives to Reduce DOE's GHG Emissions | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Capturing Fugitives to Reduce DOE's GHG Emissions Capturing Fugitives to Reduce DOE's GHG Emissions Capturing Fugitives to Reduce DOE's GHG Emissions November 15, 2011 - 2:04pm Addthis An electrician foreman for the Western Area Power Administration checks a circuit breaker at the Ault Substation in eastern Colorado. The circuit breaker, containing 85 lbs of SF6, protects equipment in the substation against damage from excessive electrical currents | Courtesy of Western Area Power Administration. An electrician foreman for the Western Area Power Administration checks a circuit breaker at the Ault Substation in eastern Colorado. The circuit breaker, containing 85 lbs of SF6, protects equipment in the substation against damage from excessive electrical currents | Courtesy of Western Area Power Administration.

3

Reducing dust emissions at OAO Alchevskkoks coke battery 10A  

Science Conference Proceedings (OSTI)

Coke battery 10A with rammed batch is under construction at OAO Alchevskkoks. The design documentation developed by Giprokoks includes measures for reducing dust emissions to the atmosphere. Aspiration systems with dry dust trapping are employed in the new components of coke battery 10A and in the existing coke-sorting equipment. Two-stage purification of dusty air in cyclones and bag filters is employed for the coke-sorting equipment. This system considerably reduces coke-dust emissions to the atmosphere.

T.F. Trembach; E.N. Lanina [Giprokoks, the State Institute for the Design of Coke-Industry Enterprises, Kharkov (Ukraine)

2009-07-15T23:59:59.000Z

4

NETL: Fugitive Gas Emissions Detection Facilities  

NLE Websites -- All DOE Office Websites (Extended Search)

Fugitive Gas Emissions Detection Facilities Fugitive Gas Emissions Detection Facilities NETL uses an array of innovative laboratory techniques and field methods to detect and monitor fugitive emissions of CO2 stored in geologic formations. By providing an accurate accounting of stored CO2 and a high level of confidence that the CO2 will permanently remain in storage, these efforts can help ensure the technical soundness and economic viability of carbon sequestration, a technology that is critical to meeting the national goal of reduced greenhouse gas emissions. Successful research to establish the stability and integrity of host formations will help developers of sequestration projects secure permits and emissions reduction credits, while preventing damage to ecosystems and ensuring public health and safety.

5

Fugitive Emissions in 2010 Site Sustainability Plans  

NLE Websites -- All DOE Office Websites (Extended Search)

Fugitive Emissions in 2010 Site Sustainability Plans Josh Silverman Chair, Fugitive Emissions Working Group Office of Environmental Policy and Assistance (HS-22) April 14, 2011 2...

6

Controlling Fugitive Emissions to Achieve GHG Reduction Goals  

NLE Websites -- All DOE Office Websites (Extended Search)

Josh Silverman Chair, DOE Fugitive Emissions Working Group Director, Office of Sustainability Support Office of Health, Safety, and Security Presented at ISM Workshop September...

7

Notes from September 13, 2012, DOE Fugitive Emissions Working...  

NLE Websites -- All DOE Office Websites (Extended Search)

emissions. The Chair encouraged FEWG members to work with their respective Site Sustainability Plan (SSP) authors to ensure that the fugitive emissions cuts and plans continue...

8

Notes from the October 14, 2010 DOE Fugitive Emissions Working...  

NLE Websites -- All DOE Office Websites (Extended Search)

(SPO) then presented on the Role of Fugitive Emissions and FEWG in DOE Strategic Sustainability Performance Plan: * The Sustainability Performance Office (SPO) will be staffed...

9

Fugitive Emissions at the Department of Energy: An Overview  

NLE Websites -- All DOE Office Websites (Extended Search)

2 GHG inventory - Fugitive emissions reduction is highlighted in DOE's Strategic Sustainability Performance Plan (SSPP) as a key strategy for achieving DOE GHG reduction goals *...

10

Engineering analysis of fugitive particulate matter emissions from cattle feedyards  

E-Print Network (OSTI)

An engineering analysis of the fugitive particulate matter emissions from a feedyard is not simple. The presence of an evening dust peak in concentration measurements downwind of a feedyard complicates the calculation of an average 24-h emission flux for the feedyard. The evening dust peak is a recurring event that occurs during evening hours when particulate matter concentration measurements increase and decrease dramatically during a short period of time. The concentrations measured during the evening can be up to 8 times the concentrations measured throughout the rest of the day. There is a perception that these concentration increases are due to increases in cattle activity as the temperature decreases during the evening. The purpose of Objective 1 of this research was to quantify the changes in concentrations based on changes in meteorological conditions and/or cattle activity. Using ISCST3, a Gaussian-based EPAapproved dispersion model used to predict concentrations downwind of the feedyard , the results of this work indicate that up to 80% of the increase in concentrations can be attributed to changes in meteorological conditions (wind speed, stability class, and mixing height.)The total fugitive particulate matter emissions on a cattle feedyard are due to two sources: unpaved roads (vehicle traffic) and pen surfaces (cattle activity). Objective 2 of this research was to quantify the mass fraction of the concentration measurements that was due to unpaved road emissions (vehicle traffic). A recent finding by Wanjura et al. (2004) reported that as much as 80% of the concentrations measured after a rain event were due to unpaved road emissions. An engineering analysis of the potential of the unpaved road emissions versus the total feedyard emissions using ISCST3 suggests that it is possible for 70 to 80% of the concentration measurements to be attributed to unpaved road emissions. The purpose of Objective 3 was to demonstrate the science used by ISCST3 to predict concentrations downwind of an area source. Results from this study indicate that the ISCST3 model utilizes a form of the Gaussian line source algorithm to predict concentrations downwind of an area source.

Hamm, Lee Bradford

2005-12-01T23:59:59.000Z

11

Air Pollution Control Regulations: No. 5 - Fugitive Dust (Rhode...  

Open Energy Info (EERE)

Yes Implementing Sector StateProvince Program Administrator Rhode Island Department of Environmental Management Primary Website http:www.dem.ri.govpubsregsregsair...

12

QUANTIFICATION OF FUGITIVE REACTIVE ALKENE EMISSIONS FROM PETROCHEMICAL PLANTS WITH PERFLUOROCARBON TRACERS.  

SciTech Connect

Recent studies demonstrate the impact of fugitive emissions of reactive alkenes on the atmospheric chemistry of the Houston Texas metropolitan area (1). Petrochemical plants located in and around the Houston area emit atmospheric alkenes, such as ethene, propene and 1,3-butadiene. The magnitude of emissions is a major uncertainty in assessing their effects. Even though the petrochemical industry reports that fugitive emissions of alkenes have been reduced to less than 0.1% of daily production, recent measurement data, obtained during the TexAQS 2000 experiment indicates that emissions are perhaps a factor of ten larger than estimated values. Industry figures for fugitive emissions are based on adding up estimated emission factors for every component in the plant to give a total estimated emission from the entire facility. The dramatic difference between estimated and measured rates indicates either that calculating emission fluxes by summing estimates for individual components is seriously flawed, possibly due to individual components leaking well beyond their estimated tolerances, that not all sources of emissions for a facility are being considered in emissions estimates, or that there are known sources of emissions that are not being reported. This experiment was designed to confirm estimates of reactive alkene emissions derived from analysis of the TexAQS 2000 data by releasing perfluorocarbon tracers (PFTs) at a known flux from a petrochemical plant and sampling both the perfluorocarbon tracer and reactive alkenes downwind using the Piper-Aztec research aircraft operated by Baylor University. PFTs have been extensively used to determine leaks in pipelines, air infiltration in buildings, and to characterize the transport and dispersion of air parcels in the atmosphere. Over 20 years of development by the Tracer Technology Center (TTC) has produced a range of analysis instruments, field samplers and PFT release equipment that have been successfully deployed in a large variety of experiments. PFTs are inert, nontoxic, noncombustible and nonreactive. Up to seven unique PFTs can be simultaneously released, sampled and analyzed and the technology is well suited for determining emission fluxes from large petrochemical facilities. The PFT experiment described here was designed to quantitate alkene emissions from a single petrochemical facility, but such experiments could be applied to other industrial sources or groups of sources in the Houston area.

SENUM,G.I.; DIETZ,R.N.

2004-06-30T23:59:59.000Z

13

Diffuse and fugitive emission dose assessment on the Hanford Site  

Science Conference Proceedings (OSTI)

On February 3, 1993, the US Department of Energy, Richland Operations Office (RL), received a Compliance Order and Information Request from the Director of the Air and Toxics Division of the US Environmental Protection Agency (EPA), Region 10. The Compliance Order requires RL to (1) evaluate all radionuclide emission points at the Hanford Site to determine which are subject to continuous emission measurement requirements in 40 Code of Federal Regulations (CFR) 61, Subpart H, and (2) continuously measure radionuclide emissions in accordance with 40 CFR 61.93. The Information Request requires RL to provide a written Compliance Plan to meet the requirements of the Compliance Order. The RL Compliance Plan included as one of its milestones the requirement to develop a Federal Facility Compliance Agreement (FFCA). An FFCA was negotiated between RL and the EPA, Region 10, and was entered into on February 7, 1994. One of the milestones was to provide EPA, Region 10, with a copy of the Federal Clean Air Act Title V operating air permit application and Air Emission Inventory (AEI) concurrent with its submission to the Washington State Department of Ecology. The AEI will include an assessment of the diffuse and fugitive emissions from the Hanford Site. This assessment does not identify any diffuse or fugitive emission source that would cause an effective dose equivalent greater than 0.1 mrem/yr.

Davis, W.E.; Schmidt, J.W.; Gleckler, B.P. [Westinghouse Hanford Co., Richland, WA (United States); Rhoads, K. [Pacific Northwest Lab., Richland, WA (United States)

1995-01-01T23:59:59.000Z

14

Reducing Sulfur Hexafluoride Use at LANSCE  

NLE Websites -- All DOE Office Websites (Extended Search)

U N C L A S S I F I E D U N C L A S S I F I E D Reducing Sulfur Hexafluoride Use at LANSCE Hank Alvestad presents to the Fugitive Emissions Working Group September 8, 2011...

15

"Blue Sky" Approaches to Reduce Greenhouse Gas Emissions: An Initial Assessment of Potential New Types of Greenhouse Gas Emissions Offsets  

Science Conference Proceedings (OSTI)

This report provides an initial assessment of potential new approaches to reducing greenhouse gas (GHG) emissions that might be capable of generating large-scale GHG emissions offsets at relatively low cost compared to other GHG mitigation options. The nine potential blue sky approaches assessed in this report include biochar, destruction of ozone depleting substances, control of natural fugitive methane seeps from coal seams, control of fugitive natural gas emissions associated with hydraulic fracturing...

2011-12-22T23:59:59.000Z

16

Fugitive Particulate Emissions from Fly Ash Disposal and Unpaved Roads at a Coal-Fired Power Plant  

Science Conference Proceedings (OSTI)

Standardized estimates of fugitive emissions resulting from bulk materials handling are subject to many potential uncertainties based on the material of interest, the specifics of operational handling, and local geography and meteorology. In 2011, the Electric Power Research Institute (EPRI) undertook the first of three phases of a field monitoring study at a power plant that investigated fugitive emissions of PM2.5 and PM10-2.5 from a large dry storage coal fly ash pile. The results incorporated ambien...

2012-06-06T23:59:59.000Z

17

Production of High Quality Dust Control Foam to Minimize Moisture Addition to Coal  

E-Print Network (OSTI)

Foam is displacing wet suppression as the method of choice for controlling fugitive emissions from coal. Coal treated by wet suppression consumes through moisture addition, a heat energy equivalent of 1 ton out of every 500 tons fired. The application of foam requires less than 10% of the moisture usually required for wet suppression. In addition, foam is a much more effective dust suppressant, especially on respirable dust (particle with an aerodynamic diameter less than 10 microns). To achieve maximum benefit from foam dust control, efficient on-site production of dry, stable foam is required. This paper discusses the basics of foam production and the many variables affecting foam expansion ratios. Successful applications of foam are also described.

Termine, F.; Jordan, S. T.

1985-05-01T23:59:59.000Z

18

Synthesis of bulk metallic glass foam by powder extrusion with a fugitive second phase  

Science Conference Proceedings (OSTI)

Bulk metallic glass foams with 12 mm in diameter and 30 mm in length having a density of 4.62 g/cm{sup 3} (approximately 58.3% of theoretical) were fabricated by extruding a powder mixture comprised of 60 vol % Ni{sub 59}Zr{sub 20}Ti{sub 16}Si{sub 2}Sn{sub 3} metallic glass blended with 40 vol % brass followed by dissolution of the fugitive brass in an aqueous HNO{sub 3} solution. The final structure consists of continuously connected, high aspect ratio metallic glass struts surrounded by {approx}40 vol % of homogeneously distributed ellipsoid-shaped pores having nominal diameters between 10 and 50 {mu}m.

Lee, Min Ha; Sordelet, Daniel J. [Materials and Engineering Physics Program, Ames Laboratory, Iowa State University, Ames, Iowa 50011 (United States)

2006-07-10T23:59:59.000Z

19

Dust-feed mechanism  

DOE Patents (OSTI)

The invention is a dust feed device for delivery of a uniform supply of dust for long periods of time to an aerosolizing means for production of a dust suspension. The device utilizes at least two tandem containers having spiral brushes within the containers which transport the dust from a supply to the aerosolizer means.

Milliman, E.M.

1981-04-06T23:59:59.000Z

20

Dust feed mechanism  

DOE Patents (OSTI)

The invention is a dust feed device for delivery of a uniform supply of dust for long periods of time to an aerosolizing means for production of a dust suspension. The device utilizes at least two tandem containers having spiral brushes within the containers which transport the dust from a supply to the aerosolizer means.

Milliman, Edward M. (Benton City, WA)

1984-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

The Atlantic Richfield Company Black Thunder mine haul road dust study. [Wyoming  

Science Conference Proceedings (OSTI)

An examination of the effectiveness of various haul road dust control measures was performed at ARCO's Black Thunder Mine near Wright, Wyoming by evaluating both visible observations and quantitative measurements of particle concentrations. In order to evaluate dust control effectiveness both a 300 foot (91.5 meter) and 175 foot (53.4 meter) section of the main coal haul road was selected for testing. The test sections were separated by a 200 foot (61 meter) buffer zone. Each test section was relatively straight and away from interferences from other mine sources. The five haul road treatment test sequences evaluated for control measure effectiveness were: an untreated road segment; water treatment two times per hour; water treatment four times per hour; previously chemically treated segment of haul road (ARCO 2400 dust suppressant); and testing after application of Coherex (10% dilution). By comparing uncontrolled situations with various controlled situations, an estimate of the control efficiency of the dust control measures was determined. Based upon the results of the study a fugitive dust control scheme was selected considering control effectiveness, economics and operational efficiency.

Maxwell, D.R.; Hormel, T.R.; Ives, J.A.

1982-06-01T23:59:59.000Z

22

Novel instrument for Dust Astronomy: Dust Telescope  

Science Conference Proceedings (OSTI)

The analysis of dust particles in space can tell us about their origin and interaction with the space environment that helps understanding the evolution of the solar system and the universe.1 2 There has been a significant advancement in dust detector/analyzer ...

Zoltan Sternovsky; Eberhard Grun; Keith Drake; Jianfeng Xie; Mihaly Horanyi; Ralf Srama; Sascha Kempf; Frank Postberg; Anna Mocker; Siegfried Auer; Harald Kruger

2011-03-01T23:59:59.000Z

23

The Smart Dust Project  

NLE Websites -- All DOE Office Websites (Extended Search)

at putting a complete sensingcommunication platform inside a cubic millimeter, including power supply, analog and digital electronics, etc. Thousands or millions of these dust...

24

Lunar dust transport and potential interactions with power system components  

DOE Green Energy (OSTI)

The lunar surface is covered by a thick blanket of fine dust. This dust may be readily suspended from the surface and transported by a variety of mechanisms. As a consequence, lunar dust can accumulate on sensitive power components, such as photovoltaic arrays and radiator surfaces, reducing their performance. In addition to natural mechanisms, human activities on the Moon will disturb significant amounts of lunar dust. Of all the mechanisms identified, the most serious is rocket launch and landing. The return of components from the Surveyor III provided a rare opportunity to observe the effects of the nearby landing of the Apollo 12 lunar module. The evidence proved that significant dust accumulation occurred on the Surveyor at a distance of 155 m. From available information on particle suspension and transport mechanisms, a series of models was developed to predict dust accumulation as a function of distance from the lunar module. The accumulation distribution was extrapolated to a future lunar lander scenario. These models indicate that accumulation is expected to be substantial even as far as 2 km from the landing site. Estimates of the performance penalties associated with lunar dust coverage on radiators and photovoltaic arrays are presented. Because of the lunar dust adhesive and cohesive properties, the most practical dust defensive strategy appears to be the protection of sensitive components from the arrival of lunar dust by location, orientation, or barriers.

Katzan, C.M.; Edwards, J.L.

1991-11-01T23:59:59.000Z

25

Electrostatic dust detector  

DOE Patents (OSTI)

An apparatus for detecting dust in a variety of environments which can include radioactive and other hostile environments both in a vacuum and in a pressurized system. The apparatus consists of a grid coupled to a selected bias voltage. The signal generated when dust impacts and shorts out the grid is electrically filtered, and then analyzed by a signal analyzer which is then sent to a counter. For fine grids a correlation can be developed to relate the number of counts observed to the amount of dust which impacts the grid.

Skinner, Charles H. (Lawrenceville, NJ)

2006-05-02T23:59:59.000Z

26

Graphite Dust Deflagration  

Science Conference Proceedings (OSTI)

The graphite moderators of retired gas-cooled nuclear reactors present a difficult challenge during demolition activities. As part of the EPRI graphite initiative on the technical issues involved in the management and disposal of irradiated nuclear graphite, this report examines the international data on dust deflagration relevant to the decommissioning of graphite-moderated reactors. The report concludes that the risk of an explosion involving graphite dust during decommissioning is extremely low, and s...

2007-03-27T23:59:59.000Z

27

Graphite Dust Deflagration  

Science Conference Proceedings (OSTI)

The graphite moderators of retired gas-cooled nuclear reactors present a difficult challenge during demolition activities. As part of the EPRI graphite initiative on the technical issues involved in the management and disposal of irradiated nuclear graphite, EPRI Report 1014797 Graphite Dust Deflagration: A Review of International Data with Particular Reference to the Decommissioning of Graphite Moderated Reactors (March 2007) examined the international data on dust deflagration relevant to the decommiss...

2007-10-03T23:59:59.000Z

28

Iron mobilization in North African dust.  

SciTech Connect

Iron is an essential nutrient for phytoplankton. Although iron-containing dust mobilized from arid regions supplies the majority of the iron to the oceans, the key flux in terms of the biogeochemical response to atmospheric deposition is the amount of soluble or bioavailable iron. Atmospheric processing of mineral aerosols by anthropogenic pollutants (e.g. sulfuric acid) may transform insoluble iron into soluble forms. Previous studies have suggested higher iron solubility in smaller particles, as they are subject to more thorough atmospheric processing due to a longer residence time than coarse particles. On the other hand, the specific mineralogy of iron in dust may also influence the particulate iron solubility in size. Compared to mineral dust aerosols, iron from combustion sources could be more soluble, and found more frequently in smaller particles. Internal mixing of alkaline dust with iron-containing minerals could significantly reduce iron dissolution in large dust aerosols due to the buffering effect, which may, in contrast, yield higher solubility in smaller particles externally mixed with alkaline dust (Ito and Feng, 2010). Here, we extend the modeling study of Ito and Feng (2010) to investigate atmospheric processing of mineral aerosols from African dust. In contrast to Asian dust, we used a slower dissolution rate for African dust in the fine mode. We compare simulated fractional iron solubility with observations. The inclusion of alkaline compounds in aqueous chemistry substantially limits the iron dissolution during long-range transport to the Atlantic Ocean: only a small fraction of iron (<0.2%) dissolves from illite in coarsemode dust aerosols with 0.45% soluble iron initially. In contrast, a significant fraction (1-1.5%) dissolves in fine-mode dust aerosols due to the acid mobilization of the iron-containing minerals externally mixed with carbonate minerals. Consequently, the model generally reproduces higher iron solubility in smaller particles as suggested by measurements over the Atlantic Ocean. Our results imply that the dissolution of iron in African dust is generally slower than that in Asian dust. Conventionally, dust is assumed as the major supply of bioavailable iron with a constant solubility at 1-2% to the remote ocean. Therefore, the timing and location of the atmospheric iron input to the ocean with detailed modeling of atmospheric processing could be different from those previously assumed. Past and future changes in aerosol supply of bioavailable iron might play a greater role in the nutrient supply for phytoplankton production in the upper ocean, as global warming has been predicted to intensify stratification and reduce vertical mixing from the deep ocean. Thus the feedback of climate change through ocean uptake of carbon dioxide as well as via aerosol-cloud interaction might be modified by the inclusion of iron chemistry in the atmosphere.

Ito, A.; Feng, Y. (Environmental Science Division); (Research Inst. for Global Change)

2011-01-01T23:59:59.000Z

29

Fractal dust grains in plasma  

Science Conference Proceedings (OSTI)

Fractal dust grains of different shapes are observed in a radially confined magnetized radio frequency plasma. The fractal dimensions of the dust structures in two-dimensional (2D) horizontal dust layers are calculated, and their evolution in the dust growth process is investigated. It is found that as the dust grains grow the fractal dimension of the dust structure decreases. In addition, the fractal dimension of the center region is larger than that of the entire region in the 2D dust layer. In the initial growth stage, the small dust particulates at a high number density in a 2D layer tend to fill space as a normal surface with fractal dimension D = 2. The mechanism of the formation of fractal dust grains is discussed.

Huang, F. [College of Science, China Agricultural University, Beijing 100083 (China); Peng, R. D. [State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing 100083 (China); Liu, Y. H. [Institute of Complexity Science, Qingdao University, Qingdao 266071 (China); Chen, Z. Y. [Department of Physics, Beijing University of Chemical Technology, Beijing 100029 (China); Ye, M. F.; Wang, L. [Institute of Physics, Chinese Academy of Science, Beijing 100190 (China)

2012-09-15T23:59:59.000Z

30

Determining inert content in coal dust/rock dust mixture  

DOE Patents (OSTI)

A method and apparatus for determining the inert content of a coal dust and rock dust mixture uses a transparent window pressed against the mixture. An infrared light beam is directed through the window such that a portion of the infrared light beam is reflected from the mixture. The concentration of the reflected light is detected and a signal indicative of the reflected light is generated. A normalized value for the generated signal is determined according to the relationship .phi.=(log i.sub.c `log i.sub.co) / (log i.sub.c100 -log i.sub.co) where i.sub.co =measured signal at 0% rock dust i.sub.c100 =measured signal at 100% rock dust i.sub.c =measured signal of the mixture. This normalized value is then correlated to a predetermined relationship of .phi. to rock dust percentage to determine the rock dust content of the mixture. The rock dust content is displayed where the percentage is between 30 and 100%, and an indication of out-of-range is displayed where the rock dust percent is less than 30%. Preferably, the rock dust percentage (RD%) is calculated from the predetermined relationship RD%=100+30 log .phi.. where the dust mixture initially includes moisture, the dust mixture is dried before measuring by use of 8 to 12 mesh molecular-sieves which are shaken with the dust mixture and subsequently screened from the dust mixture.

Sapko, Michael J. (Finleyville, PA); Ward, Jr., Jack A. (Oakmont, PA)

1989-01-01T23:59:59.000Z

31

Dust cluster explosion  

Science Conference Proceedings (OSTI)

A model for the dust cluster explosion where micron/sub-micron sized particles are accelerated at the expense of plasma thermal energy, in the afterglow phase of a complex plasma discharge is proposed. The model is tested by molecular dynamics simulations of dust particles in a confining potential. The nature of the explosion (caused by switching off the discharge) and the concomitant dust acceleration is found to depend critically on the pressure of the background neutral gas. At low gas pressure, the explosion is due to unshielded Coulomb repulsion between dust particles and yields maximum acceleration, while in the high pressure regime it is due to shielded Yukawa repulsion and yields much feebler acceleration. These results are in agreement with experimental findings. Our simulations also confirm a recently proposed electrostatic (ES) isothermal scaling relation, P{sub E}{proportional_to}V{sub d}{sup -2} (where P{sub E} is the ES pressure of the dust particles and V{sub d} is the confining volume).

Saxena, Vikrant [School of Mathematics and Physics, Queen's University Belfast, Belfast, Northern Ireland (United Kingdom); Institute for Plasma Research, Bhat, Gandhinagar (India); Avinash, K. [Department of Physics and Astrophysics, University of Delhi, New Delhi (India); Sen, A. [Institute for Plasma Research, Bhat, Gandhinagar (India)

2012-09-15T23:59:59.000Z

32

Applications of high-speed dust injection to magnetic fusion  

Science Conference Proceedings (OSTI)

It is now an established fact that a significant amount of dust is produced in magnetic fusion devices due to plasma-wall interactions. Dust inventory must be controlled, in particular for the next-generation steady-state fusion machines like ITER, as it can pose significant safety hazards and degrade performance. Safety concerns are due to tritium retention, dust radioactivity, toxicity, and flammability. Performance concerns include high-Z impurities carried by dust to the fusion core that can reduce plasma temperature and may even induce sudden termination of the plasma. We have recognized that dust transport, dust-plasma interactions in magnetic fusion devices can be effectively studied experimentally by injection of dust with known properties into fusion plasmas. Other applications of injected dust include diagnosis of fusion plasmas and edge localized mode (ELM)'s pacing. In diagnostic applications, dust can be regarded as a source of transient neutrals before complete ionization. ELM's pacing is a promising scheme to prevent disruptions and type I ELM's that can cause catastrophic damage to fusion machines. Different implementation schemes are available depending on applications of dust injection. One of the simplest dust injection schemes is through gravitational acceleration of dust in vacuum. Experiments at Los Alamos and Princeton will be described, both of which use piezoelectric shakers to deliver dust to plasma. In Princeton experiments, spherical particles (40 micron) have been dropped in a systematic and reproducible manner using a computer-controlled piezoelectric bending actuator operating at an acoustic (0,2) resonance. The circular actuator was constructed with a 2.5 mm diameter central hole. At resonance ({approx} 2 kHz) an applied sinusoidal voltage has been used to control the flux of particles exiting the hole. A simple screw throttle located {approx}1mm above the hole has been used to set the magnitude of the flux achieved for a given voltage. Particle fluxes ranging from a few tens of particle per second up to thousands of particles per second have been achieved using this simple device. To achieve higher dust injection speed, another key consideration is how to accelerate dust at controlled amount. In addition to gravity, other possible acceleration mechanisms include electrostatic, electromagnetic, gas-dragged, plasma-dragged, and laser-ablation-based acceleration. Features and limitations of the different acceleration methods will be discussed. We will also describe laboratory experiments on dust acceleration.

Wang, Zhehui [Los Alamos National Laboratory; Li, Yangfang [Max Planck Institute for Extraterrestrial Physics, Germany

2012-08-08T23:59:59.000Z

33

Dust control for draglines  

SciTech Connect

Monitoring dust levels inside draglines reveals room for improvement in how filtration systems are used and maintained. The Australian firm BMT conducted a field test program to measure airflow parameters, dust fallout rates and dust concentrations, inside and outside the machine house, on four draglines and one shovel. The study involved computational fluid dynamics (CFD) simulations. The article describes how the tests were made and gives results. It was not possible to say which of the two main filtration systems currently used on Australian draglines - Dynavane or Floseps - performs better. It would appear that more frequent maintenance and cleaning would increase the overall filtration performance and systems could be susceptible to repeat clogging in a short time. 2 figs., 1 photos.

Grad, P.

2009-09-15T23:59:59.000Z

34

TWO INTERSTELLAR DUST CANDIDATES FROM THE STARDUST AEROGEL INTERSTELLAR DUST  

E-Print Network (OSTI)

TWO INTERSTELLAR DUST CANDIDATES FROM THE STARDUST AEROGEL INTERSTELLAR DUST COLLECTOR A. J, and is expected to have collected several dozen contemporary interstellar dust particles in aerogel and aluminum@home, we have so far identified 28 tracks in the aerogel collectors. We report on the results

35

Reducing SF6 Emissions @ PPPL  

NLE Websites -- All DOE Office Websites (Extended Search)

96.4 88.4 Fuel Consumption Emissions 2015 1823.8 Fugitive Emissions Refrigerant 160 241.2 SF6 38360 21042.8 Scope 2 -Indirect Electricity Purchase 13816 13855 Scope 3 -...

36

Magnetorotational instability in plasmas with mobile dust grains  

SciTech Connect

The magnetorotational instability of dusty plasmas is investigated using the multi-fluid model and the general dispersion relation is derived based on local approximation. The dust grains are found to play an important role in the dispersion relation in the low-frequency mode and exhibit destabilizing effects on the plasma. Both the instability criterion and growth rate are affected significantly by the dust and when the dust is heavy enough to be unperturbed, the reduced dispersion relations are obtained. The instability criteria show that the dust grains have stabilizing effects on the instability when the rotation frequency decreases outwards and conversely lead to destabilizing effects when the rotation frequency increases outwards. The results are relevant to accession and protoplanetary disks.

Ren Haijun [CAS Key Laboratory of Basic Plasma Physics, Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China); Cao Jintao [Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Li Ding [CAS Key Laboratory of Basic Plasma Physics, Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China); Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)

2013-03-15T23:59:59.000Z

37

Dust in Protoplanetary Disks  

E-Print Network (OSTI)

We critically examine the best lines of evidence for grain growth in protoplanetary disks, based on modelling of observed spectral energy distributions and images of T Tauri and Herbig Ae stars. The data are consistent with millimeter-sized grains near disk midplanes, and micron-sized grains near disk surfaces. We review three channels by which grains can grow, including direct condensation from the vapor phase, grain-grain collisional sticking, and gravitational instability. The utility of dust in identifying as yet unseen extrasolar planets is highlighted.

Chiang, E I

2003-01-01T23:59:59.000Z

38

Dust in Protoplanetary Disks  

E-Print Network (OSTI)

We critically examine the best lines of evidence for grain growth in protoplanetary disks, based on modelling of observed spectral energy distributions and images of T Tauri and Herbig Ae stars. The data are consistent with millimeter-sized grains near disk midplanes, and micron-sized grains near disk surfaces. We review three channels by which grains can grow, including direct condensation from the vapor phase, grain-grain collisional sticking, and gravitational instability. The utility of dust in identifying as yet unseen extrasolar planets is highlighted.

E. I. Chiang

2003-09-08T23:59:59.000Z

39

A Dust Prediction System with TOMS Initialization  

Science Conference Proceedings (OSTI)

A dust prediction system, developed earlier at the University of Athens within the framework of the Mediterranean Dust Experiment (MEDUSE) project, was enhanced at Tel Aviv University to support the Israeli–American Mediterranean Israeli Dust ...

P. Alpert; S. O. Krichak; M. Tsidulko; H. Shafir; J. H. Joseph

2002-09-01T23:59:59.000Z

40

Climate Response to Soil Dust Aerosols  

Science Conference Proceedings (OSTI)

The effect of radiative forcing by soil dust aerosols upon climate is calculated. Two atmospheric GCM (AGCM) simulations are compared, one containing a prescribed seasonally varying concentration of dust aerosols, and the other omitting dust. ...

R. L. Miller; I. Tegen

1998-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Development of materials resistant to metal dusting degradation.  

Science Conference Proceedings (OSTI)

Metal dusting corrosion has been a serious problem in the petroleum and petrochemical industries, such as reforming and syngas production systems. This form of deterioration has led to worldwide material loss for 50 years. For the past three years, we have studied the mechanism of metal dusting for Fe- and Ni-base alloys. In this report, we present a correlation between the weight loss and depth of pits that form in Ni-base alloys. Nickel-base alloys were also tested at 1 and 14.8 atm (210 psi), in a high carbon activity environment. Higher system pressure was found to accelerate corrosion in most Ni-base alloys. To reduce testing time, a pre-pitting method was developed. Mechanical scratches on the alloy surface led to fast metal dusting corrosion. We have also developed preliminary data on the performance of weldments of several Ni-base alloys in a metal dusting environment. Finally, Alloy 800 tubes and plates used in a reformer plant were examined by scanning electron microscopy, energy dispersive X-ray, and Raman spectroscopy. The oxide scale on the surface of the Alloy 800 primarily consists of Fe{sub 1+x}Cr{sub 2-X}O{sub 4} spinel phase with high Fe content. Carbon can diffuse through this oxide scale. It was discovered that the growth of metal dusting pits could be stopped by means of a slightly oxidized alloy surface. This leads to a new way to solve metal dusting problem.

Natesan, K.; Zeng, Z.

2006-04-24T23:59:59.000Z

42

The spatial distribution of mineral dust and its shortwave radiative forcing over North Africa: Modeling sensitivities to dust emissions and aerosol size treatments  

Science Conference Proceedings (OSTI)

A fully coupled meteorology-chemistry-aerosol model (WRF-Chem) with the implementation of two dust emission schemes (GOCART and DUSTRAN) into two aerosol models (MADE/SORGAM and MOSAIC) is applied over North Africa to investigate the modeling sensitivities to dust emissions and aerosol size treatments in simulating mineral dust and its shortwave (SW) radiative forcing. Model results of the spatial distribution of mineral dust and its radiative forcing are evaluated using measurements from the AMMA SOP0 campaign in January and February of 2006 over North Africa. Our study suggests that the size distribution of emitted dust can result in significant differences (up to 100%) in simulating mineral dust and its SW radiative forcing. With the same dust emission and dry deposition processes, two aerosol models, MADE/SORGAM and MOSAIC, can yield large difference in size distributions of dust particles due to their different aerosol size treatments using modal and sectional approaches respectively. However, the difference between the two aerosol models in simulating the mass concentrations and the SW radiative forcing of mineral dust is small (< 10%). The model simulations show that mineral dust increases AOD by a factor of 2, heats the lower atmosphere (1-3 km) with a maximum rate of 0.7?0.5 K day-1 below 1 km, and reduces the downwelling SW radiation by up to 25 W m-2 on 24-hour average at surface, highlighting the importance of including dust radiative impact in understanding the regional climate of North Africa. When compared to the available measurements, WRF-Chem simulations can generally capture the measured features of mineral dust and its radiative properties over North Africa, suggesting that the model can be used to perform more extensive simulations of regional climate over North Africa.

Zhao, Chun; Liu, Xiaohong; Leung, Lai-Yung R.; Johnson, Ben; McFarlane, Sally A.; Gustafson, William I.; Fast, Jerome D.; Easter, Richard C.

2010-09-20T23:59:59.000Z

43

An observational Study of the “Interstate 5” Dust Storm Case  

Science Conference Proceedings (OSTI)

On 29 November 1991 a series of collisions involving 164 vehicles occurred on Interstate 5 in the San Joaquin Valley in California in a dust storm that reduced the visibility to near zero. The accompanying high surface winds are hypothesized to ...

Patricia M. Pauley; Nancy L. Baker; Edward H. Barker

1996-04-01T23:59:59.000Z

44

Dust and Black Carbon in Seasonal Snow Across Northern China  

Science Conference Proceedings (OSTI)

Snow is the most reflective natural surface on Earth. Its albedo (the fraction of sunlight reflected) can be reduced by small amounts of dark impurities such as dust and black carbon (BC) particles. This effect is significant for climate and the ...

Jianping Huang; Qiang Fu; Wu Zhang; Xin Wang; Rudong Zhang; Hao Ye; Stephen G. Warren

2011-02-01T23:59:59.000Z

45

ACE-ASIA: Regional Climatic and Atmospheric Chemical Effects of Asian Dust and Pollution  

Science Conference Proceedings (OSTI)

Although continental-scale plumes of Asian dust and pollution reduce the amount of solar radiation reaching the earth's surface and perturb the chemistry of the atmosphere, our ability to quantify these effects has been limited by a lack of ...

John H. Seinfeld; Gregory R. Carmichael; Richard Arimoto; William C. Conant; Frederick J. Brechtel; Timothy S. Bates; Thomas A. Cahill; Antony D. Clarke; Sarah J. Doherty; Piotr J. Flatau; Barry J. Huebert; Jiyoung Kim; Krzysztof M. Markowicz; Patricia K. Quinn; Lynn M. Russell; Philip B. Russell; Atsushi Shimizu; Yohei Shinozuka; Chul H. Song; Youhua Tang; Itsushi Uno; Andrew M. Vogelmann; Rodney J. Weber; Jung-Hun Woo; Xiao Y. Zhang

2004-03-01T23:59:59.000Z

46

HEP Fugitive - Higgs Boson  

NLE Websites -- All DOE Office Websites (Extended Search)

FOR DISCOVERY The Higgs Graphic of a plaid H Graphic made in 2001 Aliases: Higgs, Higgs Boson, H0, h0 DESCRIPTION Mass: at least 114 GeV ? Spin: Zero Charge: Netural Particle...

47

A Simple Thermodynamical Theory for Dust Devils  

Science Conference Proceedings (OSTI)

Based on the heat engine framework, a simple scaling theory for dust devils is proposed and compared to observations. This theory provides a simple physical interpretation for many of the observed characteristics of dust devils. In particular, it ...

Nilton O. Rennó; Matthew L. Burkett; Matthew P. Larkin

1998-11-01T23:59:59.000Z

48

Adding coal dust to coal batch  

Science Conference Proceedings (OSTI)

The granulometric composition of coke dust from the dry-slaking machine is determined. The influence of additions of 3-7% coke dust on the quality of industrial coking batch and the coke obtained by box coking is estimated. Adding 1% coke dust to coking batch does not markedly change the coke quality. Industrial equipment for the supply of dry-slaking dust to the batch is described.

V.S. Shved; A.V.Berezin [OAO Koks, Kemerovo (Russian Federation)

2009-05-15T23:59:59.000Z

49

Radiative impact of mineral dust on monsoon precipitation variability over West Africa  

SciTech Connect

The radiative forcing of dust and its impact on precipitation over the West Africa monsoon (WAM) region is simulated using a coupled meteorology and aerosol/chemistry model (WRF-Chem). During the monsoon season, dust is a dominant contributor to AOD over West Africa. In the standard simulation, on 24-hour domain average, dust has a cooling effect (-6.11 W/m2) at the surface, a warming effect (6.94 W/m2) in the atmosphere, and a relatively small TOA forcing (0.83 W/m2). Dust modifies the surface energy budget and atmospheric diabatic heating and hence causes lower atmospheric cooling in the daytime but warming in the nighttime. As a result, atmospheric stability is increased in the daytime and reduced in the nighttime, leading to a reduction of late afternoon precipitation by up to 0.14 mm/hour (30%) and an increase of nocturnal and early morning precipitation by up to 0.04 mm/hour (23%) over the WAM region. Dust-induced reduction of diurnal precipitation variation improves the simulated diurnal cycle of precipitation when compared to measurements. However, daily precipitation is only changed by a relatively small amount (-0.14 mm/day or -4%). On the other hand, sensitivity simulations show that, for weaker-to-stronger absorbing dust, dust longwave warming effect in the nighttime surpasses its shortwave cooling effect in the daytime at the surface, leading to a less stable atmosphere associated with more convective precipitation in the nighttime. As a result, the dust-induced change of daily WAM precipitation varies from a significant reduction of -0.40 mm/day (-12%, weaker absorbing dust) to a small increase of 0.05 mm/day (1%, stronger absorbing dust). This variation originates from the competition between dust impact on daytime and nighttime precipitation, which depends on dust shortwave absorption. Dust reduces the diurnal variation of precipitation regardless of its absorptivity, but more reduction is associated with stronger absorbing dust.

Zhao, Chun; Liu, Xiaohong; Leung, Lai-Yung R.; Hagos, Samson M.

2011-03-01T23:59:59.000Z

50

PHOTOELECTRIC CROSS-SECTIONS OF GAS AND DUST IN PROTOPLANETARY DISKS  

SciTech Connect

We provide simple polynomial fits to the X-ray photoelectric cross-sections (0.03 keV < E < 10 keV) for mixtures of gas and dust found in protoplanetary disks. Using the solar elemental abundances of Asplund et al., we treat the gas and dust components separately, facilitating the further exploration of evolutionary processes such as grain settling and gain growth. We find that blanketing due to advanced grain growth (a{sub max} > 1 {mu}m) can reduce the X-ray opacity of dust appreciably at E{sub X} {approx} 1 keV, coincident with the peak of typical T Tauri X-ray spectra. However, the reduction of dust opacity by dust settling, which is known to occur in protoplanetary disks, is probably a more significant effect. The absorption of 1-10 keV X-rays is dominated by gas opacity once the dust abundance has been reduced to about 1% of its diffuse interstellar value. The gas disk establishes a floor to the opacity at which point X-ray transport becomes insensitive to further dust evolution. Our choice of fitting function follows that of Morrison and McCammon, providing a degree of backward compatibility.

Bethell, T. J.; Bergin, Edwin A., E-mail: tbethell@umich.edu [Astronomy Department, University of Michigan, Ann Arbor, MI 48109 (United States)

2011-10-10T23:59:59.000Z

51

Dust and Ventilation Effects on Radiant Barriers: Cooling Season Energy Measurements  

Science Conference Proceedings (OSTI)

This study on the effects of attic ventilation area and type and dust buildup on horizontal and truss radiant barriers in insulated homes can help utilities reduce cooling season electric energy requirements. Increasing the ventilation area ratio and changing ventilation types had little effect on radiant barrier performance. Dust did degrade performance, but insulated homes with radiant barriers still had lower energy requirements than those without radiant barriers.

1990-05-15T23:59:59.000Z

52

Cooling season energy measurements of dust and ventilation effects on radiant barriers  

Science Conference Proceedings (OSTI)

Cooling season tests were conducted in three unoccupied ranch-style houses in Karns, Tennessee, to determine the effects on attic radiant barrier performance incurred by changes in attic ventilation area ratio, attic ventilation type, and the buildup of dust on horizontal radiant barriers. All three houses had R-19 fiberglass batt insulation in their attics. Horizontal radiant barriers were artificially dusted and the dusted barriers showed measurable performance degradations, although the dusted barriers were still superior to no radiant barriers. Dust loadings of 0.34 and 0.74 mg/cm{sup 2} reduced a clean radiant barrier surface emissivity of 0.055 to 0.125 and 0.185, respectively. Total house cooling load increases amounted to 2.3 and 8.4% compared to house loads with clean horizontal barriers, respectively. When compared to R-19 with no horizontal radiant barrier conditions, the dusted horizontal radiant barriers reduced cooling loads by about 7%. Testing showed that increasing the attic ventilation area ratio from the minimum recommended of 1/300 (1 ft{sup 2} of effective ventilation area per 300 ft{sup 2} of attic area) to 1/150 had little if any effect on the house cooling load with either truss or horizontal barriers present in the attics. Radiant barriers, however, still reduced the house cooling load. 18 refs., 17 figs., 26 tabs.

Levins, W.P.; Karnitz, M.A. (Oak Ridge National Lab., TN (USA)); Hall, J.A. (Tennessee Valley Authority, Chattanooga, TN (USA))

1990-03-01T23:59:59.000Z

53

Infrared emission from interplanetary dust  

Science Conference Proceedings (OSTI)

Standard models of the interplanetary dust emission fail to account satisfactorily for IR observations. A new model of the dust, based on very simple assumptions on the grain structure (spherical and homogeneous) and chemical composition (astronomical silicates, graphite, blackbodies) is developed. Updated values of the refractive indexes have been included in the analysis. The predictions of the model (absolute values of the fluxes, spectral shape, elongation dependence of the emission) have then been compared with all the available IR observations performed by the ARGO (balloon-borne experiment by University of Rome), AFGL and Zodiacal Infrared Project (ZIP) (rocket experiments by Air Force Geophysics Laboratory, Bedford, Mass.), and IRAS satellite. Good agreement is found when homogeneous data sets from single experiments (e.g., ZIP and ARGO) are considered separately. 19 references.

Temi, P.; De Bernardis, P.; Masi, S.; Moreno, G.; Salama, A.

1989-02-01T23:59:59.000Z

54

Dust Charging and Transport on Surfaces  

Science Conference Proceedings (OSTI)

In this paper, we review laboratory studies of dust transport on surfaces in plasmas, performed for a number of different mechanisms: 1) Dust particles were levitated in plasma sheaths by electrostatic forces balancing the gravitational force. 2) Dust was observed to spread over and lift off a surface that repels electrons in a plasma. 3) Dust was transported on surfaces having different secondary electron yields in plasma with an electron beam as a consequence of differential charging. 4) We also report a mechanism of dust transport by electric fields occurring at electron beam impact/shadow boundaries. These processes are candidates to explain the formation of dust ponds that were recently observed in craters on the asteroid Eros by the NEAR Shoemaker spacecraft.

Wang, X. [Colorado Center for Lunar Dust And Atmospheric Studies, University of Colorado, Boulder, CO 80309 (United States); Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309 (United States); Robertson, S. [Colorado Center for Lunar Dust And Atmospheric Studies, University of Colorado, Boulder, CO 80309 (United States); Department of Physics, University of Colorado, Boulder, CO 80309 (United States); Horanyi, M. [Colorado Center for Lunar Dust And Atmospheric Studies, University of Colorado, Boulder, CO 80309 (United States); Department of Physics, University of Colorado, Boulder, CO 80309 (United States); Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309 (United States)

2011-11-29T23:59:59.000Z

55

Dust negative ion acoustic shock waves considering dust size distribution effect  

Science Conference Proceedings (OSTI)

A multi-ion dusty plasma containing hot isothermal electrons, ions (light positive ions and heavy negative ions), and extremely and negatively charged dust grains is studied in the present paper. The dust negative ion acoustic shock waves have been investigated by employing the reductive perturbation method. How the dust size distribution affects the height and the thickness of the nonlinear shock wave is studied. It is noted that the different dust size distribution has different shock wave form and different moving speed.

Ma Yirong; Wang Canglong; Zhang Jianrong; Sun Jianan; Duan Wenshan [College of Physics and Electronic Engineering and Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou 730070, China and Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Yang Lei [College of Physics and Electronic Engineering and Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou 730070 (China) and Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Department of Physics, Lanzhou University, Lanzhou 730000 (China)

2012-11-15T23:59:59.000Z

56

Cooling season energy measurements of dust and ventilation effects on radiant barriers  

Science Conference Proceedings (OSTI)

Cooling season tests were conducted in three unoccupied ranch-style houses in Karns, Tennessee, to determine the effects on attic radiant barrier performance incurred by changes in attic ventilation area ratio, attic ventilation type, and the buildup of dust on horizontal radiant barriers. All three houses had R-19 fiberglass batt insulation in their attics. Horizontal radiant barriers were artificially dusted and the dusted barriers showed measurable performance degradations, although the dusted barriers were still superior to no radiant barriers. Dust loadings of 0.34 and 0.74 mg/cm{sup 2} reduced a clean radiant barrier surface emissivity of 0.055 to 0.125 and 0.185, respectively. Total house cooling load increases amounted to 2.3 and 8.4% compared to house loads with clean horizontal barriers, respectively. When compared to R-19 with no horizontal radiant barrier conditions, the dusted horizontal radiant barriers reduced cooling loads by about 7%. 18 refs., 18 figs., 30 tabs.

Levins, W.P.; Karnitz, M.A. (Oak Ridge National Lab., TN (USA)); Hall, J.A. (Tennessee Valley Authority, Knoxville, TN (USA))

1990-02-01T23:59:59.000Z

57

A Model for Long-Range Transport of Desert Dust  

Science Conference Proceedings (OSTI)

An Eulerian model for dust transport in the atmosphere is designed, and a new parameterization scheme for dust uptake is developed. The model results are quantitatively compared with satellite observations for an intense dust transport event that ...

Slobodan Ni?kovi?; Srdjan Dobri?i?

1996-11-01T23:59:59.000Z

58

Low intensity dust ion-acoustic shock waves due to dust charge fluctuation in a nonextensive dusty plasma  

SciTech Connect

The properties of low intensity dust ion acoustic shock waves are studied in a charge varying dusty plasma with nonextensive electrons. Owing to the departure from the Maxwellian electron distribution to a nonextensive one, the modified electrostatic charging of a spherical dust particle in plasma with ion streaming speed is considered. Based on the weakly nonlinear analysis, a new relationship between the low intensity localized disturbances and nonextensive electrons is derived. It is found that both strength and steepness of shock structures arise as the electrons evolve far from their thermodynamic equilibrium in such plasma with parameter ranges corresponding to Saturn's rings. It is also shown that the ion temperature and population of electrons reduce the possibility of the formation of the shock profile.

Alinejad, H. [Department of Physics, Faculty of Basic Science, Babol University of Technology, Babol 47148-71167 (Iran, Islamic Republic of); Shahmansory, M. [Department of Physics, Faculty of Science, Arak University, Arak 38156-8-8349 (Iran, Islamic Republic of)

2012-08-15T23:59:59.000Z

59

Heavy metals hazardous components of Eaf dust  

Science Conference Proceedings (OSTI)

Electric arc furnace (EAF) dust is a waste generated in the EAF during the steel production process. Among different wastes, EAF dust represents one of the most hazardous, since it contains heavy metals such as Zn, Fe, Cr, Cd and Pb. The goal of the ... Keywords: electric arc furnace (EAF), furnace additives, hazard components, heavy metals, scrap composition, x-ray fluorescence spectroscopy

Cristiana-Zizi Rizescu; Zorica Bacinschi; Elena Valentina Stoian; Aurora Poinescu; Dan Nicolae Ungureanu

2011-02-01T23:59:59.000Z

60

Observing Cold Dust with Herschel / SPIRE  

Science Conference Proceedings (OSTI)

A major component of the emission of many galaxies is in the Far Infrared and the Sub?mmillimeter. UV photons from stars are absorbed by dust and re?emitted at longer wavelengths. Fairly cold dust was found in large spirals by the Infrared Space Observatory and the Spitzer Observatory but their longest wavelength filters were centered at 200 and 160 microns respectively

Bernhard Schulz; The SPIRE Consortium

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Measurement of nicotine in household dust  

Science Conference Proceedings (OSTI)

An analytical method of measuring nicotine in house dust was optimized and associations among three secondhand smoking exposure markers were evaluated, i.e., nicotine concentrations of both house dust and indoor air, and the self-reported number of cigarettes smoked daily in a household. We obtained seven house dust samples from self-reported nonsmoking homes and 30 samples from smoking homes along with the information on indoor air nicotine concentrations and the number of cigarettes smoked daily from an asthma cohort study conducted by the Johns Hopkins Center for Childhood Asthma in the Urban Environment. House dust nicotine was analyzed by isotope dilution gas chromatography-mass spectrometry (GC/MS). Using our optimized method, the median concentration of nicotine in the dust of self-reported nonsmoking homes was 11.7 ng/mg while that of smoking homes was 43.4 ng/mg. We found a substantially positive association (r=0.67, P<0.0001) between house dust nicotine concentrations and the numbers of cigarettes smoked daily. Optimized analytical methods showed a feasibility to detect nicotine in house dust. Our results indicated that the measurement of nicotine in house dust can be used potentially as a marker of longer term SHS exposure.

Kim, Sungroul [Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Institute for Global Tobacco Control, 627 N. Washington Street, 2nd Floor Baltimore, MD 21205 (United States); Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205 (United States)], E-mail: srkim@jhsph.edu; Aung, Ther; Berkeley, Emily [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205 (United States); Diette, Gregory B. [Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205 (United States); Department of Medicine, Johns Hopkins University School of Medicine (United States); Breysse, Patrick N. [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205 (United States)

2008-11-15T23:59:59.000Z

62

Dust Combustion Safety Issues for Fusion Applications  

SciTech Connect

This report summarizes the results of a safety research task to identify the safety issues and phenomenology of metallic dust fires and explosions that are postulated for fusion experiments. There are a variety of metal dusts that are created by plasma erosion and disruptions within the plasma chamber, as well as normal industrial dusts generated in the more conventional equipment in the balance of plant. For fusion, in-vessel dusts are generally mixtures of several elements; that is, the constituent elements in alloys and the variety of elements used for in-vessel materials. For example, in-vessel dust could be composed of beryllium from a first wall coating, tungsten from a divertor plate, copper from a plasma heating antenna or diagnostic, and perhaps some iron and chromium from the steel vessel wall or titanium and vanadium from the vessel wall. Each of these elements has its own unique combustion characteristics, and mixtures of elements must be evaluated for the mixture’s combustion properties. Issues of particle size, dust temperature, and presence of other combustible materials (i.e., deuterium and tritium) also affect combustion in air. Combustion in other gases has also been investigated to determine if there are safety concerns with “inert” atmospheres, such as nitrogen. Several coolants have also been reviewed to determine if coolant breach into the plasma chamber would enhance the combustion threat; for example, in-vessel steam from a water coolant breach will react with metal dust. The results of this review are presented here.

L. C. Cadwallader

2003-05-01T23:59:59.000Z

63

Physical and Chemical Characterization of Kuwaiti Atmospheric Dust and Synthetic Dusts: Effects on the Pressure Drop and Fractional Efficiency of HEPA Filters  

E-Print Network (OSTI)

The importance of clean air to the indoor air quality affecting the well-being of human occupants and rising energy consumption has highlighted the critical role of air filter performance. Actual performance of air filters installed in air handling units in Kuwait tends to deviate from the performance predicted by laboratory results. Therefore, accurate filter performance prediction is important to estimate filter lifetime, and to reduce energy and maintenance operating costs. To ensure appropriate filter selection for a specific application, particulate contaminants existing in the Kuwaiti atmospheric dust were identified and characterized both physically and chemically and compared to the synthetic dust used in laboratories. This paper compares the physical and chemical characterization Kuwaiti atmospheric dust with the available commercial synthetic dusts. It also tests full scale HEPA pleated V-shaped filters used in Heating Ventilation and Air Conditioning (HVAC) and gas turbine applications to study the effect of different synthetic dust types and their particle size distributions on the pressure drop and fractional efficiency using DEHS testing according to DIN 1822.

Al-Attar, I.; Wakeman, R. J.; Tarleton, E. S.; Husain, A.

2010-01-01T23:59:59.000Z

64

Pebble Bed Reactor Dust Production Model  

SciTech Connect

The operation of pebble bed reactors, including fuel circulation, can generate graphite dust, which in turn could be a concern for internal components; and to the near field in the remote event of a break in the coolant circuits. The design of the reactor system must, therefore, take the dust into account and the operation must include contingencies for dust removal and for mitigation of potential releases. Such planning requires a proper assessment of the dust inventory. This paper presents a predictive model of dust generation in an operating pebble bed with recirculating fuel. In this preliminary work the production model is based on the use of the assumption of proportionality between the dust production and the normal force and distance traveled. The model developed in this work uses the slip distances and the inter-pebble forces computed by the authors’ PEBBLES. The code, based on the discrete element method, simulates the relevant static and kinetic friction interactions between the pebbles as well as the recirculation of the pebbles through the reactor vessel. The interaction between pebbles and walls of the reactor vat is treated using the same approach. The amount of dust produced is proportional to the wear coefficient for adhesive wear (taken from literature) and to the slip volume, the product of the contact area and the slip distance. The paper will compare the predicted volume with the measured production rates. The simulation tallies the dust production based on the location of creation. Two peak production zones from intra pebble forces are predicted within the bed. The first zone is located near the pebble inlet chute due to the speed of the dropping pebbles. The second peak zone occurs lower in the reactor with increased pebble contact force due to the weight of supported pebbles. This paper presents the first use of a Discrete Element Method simulation of pebble bed dust production.

Abderrafi M. Ougouag; Joshua J. Cogliati

2008-09-01T23:59:59.000Z

65

Dust and ventilation effects on radiant barriers: Cooling season energy measurements  

Science Conference Proceedings (OSTI)

Cooling season tests were conducted in three unoccupied ranch-style houses in Karns, Tennessee, to determine the effects on attic radiant barrier performance incurred by changes in attic ventilation area ratio, attic ventilation type, and the buildup of dust on horizontal radiant barriers. All three houses had R-19 fiberglass batt insulation in their attics. Horizontal radiant barriers were artificially dusted and the dusted barriers showed measurable performance degradations, although the dusted barriers were still superior to no radiant barriers. Dust loadings of 0.34 and 0.74 mg/cm{sup 2} reduced a clean radiant barrier surface emissivity of 0.055 to 0.125 and 0.185, respectively. Total house cooling load increases amounted to 2.3 and 8.4% compared to house loads with clean horizontal barriers, respectively. When compared to R-19 with no horizontal radiant barrier conditions, the dusted horizontal radiant barriers reduced cooling loads by about 7%. Testing showed that increasing the attic ventilation area ratio from the minimum recommended of 1/300 to 1/150 had little if any effect on the house cooling load with either truss or horizontal barriers present in the attics. Radiant barriers, however, still reduced the house cooling load. There was essentially no difference in house cooling load reduction between either ridge/soffit or gable/soffit vent type with a truss radiant barrier, as both reduced cooling loads by about 8% when compared to no radiant barrier conditions. The attic-ventilation-type testing was done with a ventilation area ratio of 1/150.

Levins, W.P.; Karnitz, M.A. (Oak Ridge National Lab., TN (USA)); Hall, J.A. (Tennessee Valley Authority, Knoxville, TN (USA))

1990-05-01T23:59:59.000Z

66

Reduce Stress!  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Stress! Stress! x Take a break every hour. Do some relaxation or stretching exercises or talk with someone about topics unrelated to work. Give your body and mind a rest. x Massage your hands and forearms several times a day with a vitamin E lotion. The massage will improve circulation and break up adhesions. Since you can't touch a keyboard until the lotion is absorbed, it also enforces a good break. x Massage the muscles in your neck working your way down from the skull to the shoulders, applying more force to the larger muscles as you go down. x Periodically evaluate your environment for ways to reduce stress. Try to keep your desk uncluttered so you can always find things. Make sure programs are set up correctly on the computer, and see if you can use a macro program to reduce

67

Dust Acoustic Shock Waves in Adiabatic Hot Dusty Plasmas  

Science Conference Proceedings (OSTI)

It is known that to have a monotonic or oscillatory shock wave a source of dissipation is needed. In this study, we considered the dust charge variation as a source of dissipation. By using the reductive perturbation technique, the nonlinear Burgers equation is derived and the shock-like solution is determined. The effects of dust temperature on different characteristics of dust acoustic shock wave are discussed. It is found out that dust thickness is not affected by dust temperature while for every dusty plasma systems there is dust critical temperature T{sub dc}, for which the dust acoustic shock height will be maximum.

Asgari, H.; Muniandy, S. V.; Wong, C. S. [Plasma Research Laboratory, Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2011-03-30T23:59:59.000Z

68

Dust Lofting and Ingestion by Supercell Storms  

Science Conference Proceedings (OSTI)

Recent research pertaining to aerosol impacts on cloud microphysics has shown a need for understanding mineral dust entrainment into moist convection. The goal of this study is to examine the pathways in which nonmicrophysically active mineral ...

Robert B. Seigel; Susan C. van den Heever

2012-05-01T23:59:59.000Z

69

Dust Intrusion Events into the Mediterranean Basin  

Science Conference Proceedings (OSTI)

In this study seven dust intrusion events were identified and analyzed in the central and eastern part of the Mediterranean Sea beginning August 1988 and ending September 1989. In order to locate their sources, characterize their mode, and ...

U. Dayan; J. Heffter; J. Miller; G. Gutman

1991-08-01T23:59:59.000Z

70

He Puff System For Dust Detector Upgrade  

SciTech Connect

Local detection of surface dust is needed for the safe operation of next-step magnetic fusion devices such as ITER. An electrostatic dust detector, based on a 5 cm x 5 cm grid of interlocking circuit traces biased to 50 V, has been developed to detect dust on remote surfaces and was successfully tested for the first time on the National Spherical Torus Experiment (NSTX). We report on a helium puff system that clears residual dust from this detector and any incident debris or fibers that might cause a permanent short circuit. The entire surface of the detector was cleared of carbon particles by two consecutive helium puffs delivered by three nozzles of 0.45 mm inside diameter. The optimal configuration was found to be with the nozzles at an angle of 30o with respect to the surface of the detector and a helium backing pressure of 6 bar. __________________________________________________

B. Rais, C.H. Skinner A.L. Roquemore

2010-10-01T23:59:59.000Z

71

Dust trajectory sensor: Accuracy and data analysis  

Science Conference Proceedings (OSTI)

The Dust Trajectory Sensor (DTS) instrument is developed for the measurement of the velocity vector of cosmic dust particles. The trajectory information is imperative in determining the particles' origin and distinguishing dust particles from different sources. The velocity vector also reveals information on the history of interaction between the charged dust particle and the magnetospheric or interplanetary space environment. The DTS operational principle is based on measuring the induced charge from the dust on an array of wire electrodes. In recent work, the DTS geometry has been optimized [S. Auer, E. Gruen, S. Kempf, R. Srama, A. Srowig, Z. Sternovsky, and V Tschernjawski, Rev. Sci. Instrum. 79, 084501 (2008)] and a method of triggering was developed [S. Auer, G. Lawrence, E. Gruen, H. Henkel, S. Kempf, R. Srama, and Z. Sternovsky, Nucl. Instrum. Methods Phys. Res. A 622, 74 (2010)]. This article presents the method of analyzing the DTS data and results from a parametric study on the accuracy of the measurements. A laboratory version of the DTS has been constructed and tested with particles in the velocity range of 2-5 km/s using the Heidelberg dust accelerator facility. Both the numerical study and the analyzed experimental data show that the accuracy of the DTS instrument is better than about 1% in velocity and 1 deg. in direction.

Xie, J.; Horanyi, M. [NASA Lunar Science Institute: Colorado Center for Lunar Dust and Atmospheric Studies, and Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303 (United States); Departments of Physics, University of Colorado, Boulder, Colorado 80309 (United States); Sternovsky, Z. [NASA Lunar Science Institute: Colorado Center for Lunar Dust and Atmospheric Studies, and Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303 (United States); Department of Aerospace Engineering Sciences, University of Colorado, Boulder, Colorado 80309 (United States); Gruen, E.; Duncan, N.; Drake, K.; Le, H. [NASA Lunar Science Institute: Colorado Center for Lunar Dust and Atmospheric Studies, and Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303 (United States); Auer, S. [A and M Associates, P. O. Box 421, Basye, Virginia 22810 (United States); Srama, R. [Max-Planck-Institute for Nuclear Physics, Heidelberg 69029 (Germany); Institute of Space Systems, University of Stuttgart, Stuttgart 70569 (Germany)

2011-10-15T23:59:59.000Z

72

Thermo-Oxidation of Tokamak Carbon Dust  

Science Conference Proceedings (OSTI)

The oxidation of dust and flakes collected from the DIII-D tokamak, and various commercial dust specimens, has been measured at 350 ºC and 2.0 kPa O2 pressure. Following an initial small mass loss, most of the commercial dust specimens showed very little effect due to O2 exposure. Similarly, dust collected from underneath DIII-D tiles, which is thought to comprise largely Grafoil™ particulates, also showed little susceptibility to oxidation at this temperature. However, oxidation of the dust collected from tile surfaces has led to ~ 18% mass loss after 8 hours; thereafter, little change in mass was observed. This suggests that the surface dust includes some components of different composition and/or structure – possibly fragments of codeposited layers. The oxidation of codeposit flakes scraped form DIII-D upper divertor tiles showed an initial 25% loss in mass due to heating in vacuum, and the gradual loss of 30-38% mass during the subsequent 24 hours exposure to O2. This behavior is significantly different from that observed for the oxidation of thinner DIII-D codeposit specimens which were still adhered to tile surfaces, and this is thought to be related to the low deuterium content (D/C ~ 0.03 – 0.04) of the flakes.

J.W. Davis; B.W.N. Fitzpatrick; J.P. Sharpe; A.A. Haasz

2008-04-01T23:59:59.000Z

73

Numerical Simulation of Dust Lifting within Dust Devils—Simulation of an Intense Vortex  

Science Conference Proceedings (OSTI)

Based on an advanced dust devil–scale large-eddy simulation (LES) model, the atmosphere flow of a modeled dust devil in a quasi–steady state was first simulated to illustrate the characteristics of the gas phase field in the mature stage, ...

Zhaolin Gu; Yongzhi Zhao; Yun Li; Yongzhang Yu; Xiao Feng

2006-10-01T23:59:59.000Z

74

Estimating Environmental Exposures to Indoor Contaminants using Residential-Dust Samples  

E-Print Network (OSTI)

congeners measured in residential-dust samples from selectedcongeners measured in residential-dust samples from selecteda)pyrene measured in residential-dust samples from selected

Whitehead, Todd Patrick

2011-01-01T23:59:59.000Z

75

Propagation of nonlinear dust magnetoacoustic waves in cylindrical geometry  

SciTech Connect

The cylindrical dust magnetoacoustic shocks in dissipative and solitons in non-dissipative dust-ion plasmas are studied. The dust particles are assumed to be fully negatively charged so that the density of electrons in comparison with dust and ions is negligible. The cylindrical Korteweg-de Vries Burgers and cylindrical Korteweg-de Vries equations are derived for dust magnetosonic waves by employing the reductive perturbation method. It is found that dust plasma parameters such as dust charge number, dust density, and ion temperature have strong influence on the profile of dust magnetoacoustic shocks and solitons. The results are also obtained numerically by using the data from laboratory experiments on dusty plasmas.

Hussain, S.; Mahmood, S. [Theoretical Plasma Physics Division (TPPD), PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan) and Department of Physics and Applied Physics (DPAM), PIEAS, P.O. Nilore, Islamabad 44000 (Pakistan)

2011-12-15T23:59:59.000Z

76

INTERPRETATION OF (596) SCHEILA'S TRIPLE DUST TAILS  

Science Conference Proceedings (OSTI)

Strange-looking dust cloud around asteroid (596) Scheila was discovered on 2010 December 11.44-11.47. Unlike normal cometary tails, it consisted of three tails and faded within two months. We constructed a model to reproduce the morphology of the dust cloud based on the laboratory measurement of high-velocity impacts and the dust dynamics. As a result, we succeeded in reproducing the peculiar dust cloud by an impact-driven ejecta plume consisting of an impact cone and downrange plume. Assuming an impact angle of 45 Degree-Sign , our model suggests that a decameter-sized asteroid collided with (596) Scheila from the direction of ({alpha}{sub im}, {delta}{sub im}) = (60 Degree-Sign , -40 Degree-Sign ) in J2000 coordinates on 2010 December 3. The maximum ejection velocity of the dust particles exceeded 100 m s{sup -1}. Our results suggest that the surface of (596) Scheila consists of materials with low tensile strength.

Ishiguro, Masateru [Department of Physics and Astronomy, Seoul National University, Gwanak, Seoul 151-742 (Korea, Republic of); Hanayama, Hidekazu; Watanabe, Jun-ichi; Miyaji, Takeshi; Fukushima, Hideo [Ishigakijima Astronomical Observatory, National Astronomical Observatory of Japan, Ishigaki, Okinawa 907-0024 (Japan); Hasegawa, Sunao; Sarugaku, Yuki [Institute of Space and Astronautical Science (ISAS), JAXA, Sagamihara, Kanagawa 252-5210 (Japan); Fujiwara, Hideaki; Terada, Hiroshi [Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720 (United States); Hsieh, Henry H. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Vaubaillon, Jeremie J. [Observatoire de Paris, I.M.C.C.E., Denfert Rochereau, Bat. A., FR-75014 Paris (France); Kawai, Nobuyuki [Department of Physics, Tokyo Institute of Technology, Meguro, Tokyo 152-8551 (Japan); Yanagisawa, Kenshi; Kuroda, Daisuke [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Asaguchi, Okayama 719-0232 (Japan); Ohta, Kouji [Department of Astronomy, Kyoto University, Sakyo, Kyoto 606-8502 (Japan); Hamanowa, Hiromi [Hamanowa Astronomical Observatory, Motomiya, Fukushima 969-1204 (Japan); Kim, Junhan [Yangcheon-gu, Seoul (Korea, Republic of); Pyo, Jeonghyun [Korea Astronomy and Space Science Institute (KASI), Daejeon 305-348 (Korea, Republic of); Nakamura, Akiko M., E-mail: ishiguro@snu.ac.kr [Department of Earth and Planetary Sciences, Kobe University, Nada, Kobe 657-8501 (Japan)

2011-11-15T23:59:59.000Z

77

A classification of spherically symmetric self-similar dust models  

E-Print Network (OSTI)

We classify all spherically symmetric dust solutions of Einstein's equations which are self-similar in the sense that all dimensionless variables depend only upon $z\\equiv r/t$. We show that the equations can be reduced to a special case of the general perfect fluid models with equation of state $p=\\alpha \\mu$. The most general dust solution can be written down explicitly and is described by two parameters. The first one (E) corresponds to the asymptotic energy at large $|z|$, while the second one (D) specifies the value of z at the singularity which characterizes such models. The E=D=0 solution is just the flat Friedmann model. The 1-parameter family of solutions with z>0 and D=0 are inhomogeneous cosmological models which expand from a Big Bang singularity at t=0 and are asymptotically Friedmann at large z; models with E>0 are everywhere underdense relative to Friedmann and expand forever, while those with E0 ones. The 2-parameter solutions with D>0 again represent inhomogeneous cosmological models but the Big Bang singularity is at $z=-1/D$, the Big Crunch singularity is at $z=+1/D$, and any particular solution necessarily spans both z0. While there is no static model in the dust case, all these solutions are asymptotically ``quasi-static'' at large $|z|$. As in the D=0 case, the ones with $E \\ge 0$ expand or contract monotonically but the latter may now contain a naked singularity. The ones with E<0 expand from or recollapse to a second singularity, the latter containing a black hole.

B. J. Carr

2000-03-02T23:59:59.000Z

78

Dust Studies in DIII-D and TEXTOR  

SciTech Connect

Studies of naturally occurring and artificially introduced carbon dust are conducted in DIII-D and TEXTOR. In DIII-D, dust does not present operational concerns except immediately after entry vents. Submicron sized dust is routinely observed using Mie scattering from a Nd:Yag laser. The source is strongly correlated with the presence of Type I edge localized modes (ELMs). Larger size (0.005-1 mm diameter) dust is observed by optical imaging, showing elevated dust levels after entry vents. Inverse dependence of the dust velocity on the inferred dust size is found from the imaging data. Direct heating of the dust particles by the neutral beam injection (NBI) and acceleration of dust particles by the plasma flows are observed. Energetic plasma disruptions produce significant amounts of dust. Large flakes or debris falling into the plasma may result in a disruption. Migration of pre-characterized carbon dust is studied in DIII-D and TEXTOR by introducing micron-size dust in plasma discharges. In DIII-D, a sample holder filled with {approx}30 mg of dust is introduced in the lower divertor and exposed to high-power ELMing H-mode discharges with strike points swept across the divertor floor. After a brief exposure ({approx}0.1 s) at the outer strike point, part of the dust is injected into the plasma, raising the core carbon density by a factor of 2-3 and resulting in a twofold increase of the radiated power. In TEXTOR, instrumented dust holders with 1-45 mg of dust are exposed in the scrape-off layer 0-2 cm radially outside of the last closed flux surface in discharges heated with neutral beam injection (NBI) power of 1.4 MW. At the given configuration of the launch, the dust did not penetrate the core plasma and only moderately perturbed the edge plasma, as evidenced by an increase of the edge carbon content.

Rudakov, D L; Litnovsky, A; West, W P; Yu, J H; Boedo, J A; Bray, B D; Brezinsek, S; Brooks, N H; Fenstermacher, M E; Groth, M; Hollmann, E M; Huber, A; Hyatt, A W; Krasheninnikov, S I; Lasnier, C J; Moyer, R A; Pigarov, A Y; Philipps, V; Pospieszczyk, A; Smirnov, R D; Sharpe, J P; Solomon, W M; Watkins, J G; Wong, C C

2009-02-17T23:59:59.000Z

79

In-depth survey report of silica flour dust during packing, transfer, and shipping at the Central Silica Company, Glass Rock Plant, Glass Rock, Ohio  

Science Conference Proceedings (OSTI)

A visit was made to the Central Silica Company, Glass Rock, Ohio to evaluate methods used to control employee exposure to silica dust. The control methods at this company included careful handling and transfer of damp materials, exhaust ventilation, good housekeeping procedures, and the use of respiratory protection. Evaluations were made of the packing area, transfer point, inside loading trucks, and ambient air at sections of the flour building. Control systems included a good exhaust-ventilation system and four ventilation hoods. Evaluations were made of samples collected by an MSA gravimeter dust sampler, the Del High volume electrostatic precipitation, and bulk and rafter samples. Dust control methods appeared to be effective due to the existence of good engineering controls, good work practices, and an effective respiratory protection program. Additional control measures included the handling of the ore as a damp material, thus reducing the generation of dust particles. Outside dust sources were being reduced. Most of the product was shipped in bulk. Plastic wrapping was used around pallet loads to reduce bag breakage and dust dispersion. A filtered air system controlled low dust levels in the Pebble Mill control room. Enclosed screens operated under negative pressure separated fine from coarse product at the process building.

Caplan, P.E.; Reed, L.D.; Amendola, A.A.; Cooper, T.C.

1981-12-01T23:59:59.000Z

80

Misers gold dust collection and cloud characterization  

SciTech Connect

MISERS GOLD was a surface detonation of 2445 tons of ammonium nitrate-fuel oil blasting agent conducted by the Defense Nuclear Agency for a variety of research purposes. This report presents the results of an experiment designed to study the dust cloud over the 24-hour period following the detonation. The cloud was sampled by aircraft to obtain material needed to characterize the quantity of dust lofted, the source regions of the cloud, and the size, shape, and mineralogical characteristics of the particles. Elemental tracers and organic dyes were emplaced in the charge and in surrounding areas. Analyses were done by instrumental neutron activation analysis (INAA), fluorimetry, scanning electron microscopy (SEM), and energy-dispersive spectrometry (EDS). Tracer data define the source regions of the dust cloud. Extensive particle size distribution data were obtained. 12 figs.

Mason, A.S.; Finnegan, D.L.; Bayhurst, G.K.; Raymond, R. Jr.; Hagan, R.C.; Luedemann, G.; Wohletz, K.H.

1991-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Impact of Transport Schemes on Modeled Dust Concentrations  

Science Conference Proceedings (OSTI)

A sensitivity study is performed with the CHIMERE-DUST chemistry transport model in order to evaluate the modeled mineral dust spread due to the horizontal transport scheme accuracy. Three different schemes are implemented in the model: the ...

Maria Raffaella Vuolo; Laurent Menut; Hélène Chepfer

2009-06-01T23:59:59.000Z

82

Historical Records of Asian Dust Events (Hwangsa) in Korea  

Science Conference Proceedings (OSTI)

The observation of dust events in Korea must have been important through its long history because of its geographical and meteorological setting. Descriptions about dust events were well documented in historical archives, such as Samguk sagi (57 ...

Youngsin Chun; Hi-Ku Cho; Hyo-Sang Chung; Meehye Lee

2008-06-01T23:59:59.000Z

83

Effects of plasma particle trapping on dust-acoustic solitary waves in an opposite polarity dust-plasma medium  

SciTech Connect

Dust acoustic solitary waves in a dusty plasma containing dust of opposite polarity (adiabatic positive and negative dust), non-isothermal electrons and ions (following vortex like distribution) are theoretically investigated by employing pseudo-potential approach, which is valid for arbitrary amplitude structures. The propagation of small but finite amplitude solitary structures is also examined by using the reductive perturbation method. The basic properties of large (small) amplitude solitary structures are investigated by analyzing the energy integral (modified Korteweg-de Vries equation). It is shown that the effects of dust polarity, trapping of plasma particles (electrons and ions), and temperatures of dust fluids significantly modify the basic features of the dust-acoustic solitary structures that are found to exist in such an opposite polarity dust-plasma medium. The relevance of the work in opposite polarity dust-plasma, which may occur in cometary tails, upper mesosphere, Jupiter's magnetosphere, is briefly discussed.

Ahmad, Zulfiqar [Institute of Physics and Electronics, University of Peshawar, 25000 Peshawar (Pakistan); Mushtaq, A. [Department of Physics, Abdul Wali Khan University, Mardan 23200 (Pakistan); National Center for Physics, Shahdrah Valley Road, Islamabad 44000 (Pakistan); Mamun, A. A. [Department of Physics, Jahangirnagar University Savar, Dhaka 1342 (Bangladesh)

2013-03-15T23:59:59.000Z

84

A Model for Saharan Dust Transport  

Science Conference Proceedings (OSTI)

In this paper the source strength and the deposition rate of the dust emerging from the Sahara are assessed. For this purpose a multichannel sunphotometer has been developed and a turbidity network covering 11 stations has been set up in the ...

Guillaume A. d'Almeida

1986-07-01T23:59:59.000Z

85

Dust Mitigation Methods for Coal Combustion Products  

Science Conference Proceedings (OSTI)

Coal-fired power plants generate coal combustion products (CCPs) requiring management for storage and disposal. These products are often stored in facilities such as landfills or placed in temporary storage pads for short or long durations. At these facilities, there is a need to address dust mitigation concerns in order to comply with environmental permits, ...

2013-08-27T23:59:59.000Z

86

Radiative Heating Rates for Saharan Dust  

Science Conference Proceedings (OSTI)

A combined longwave and shortwave radiative transfer model was used to determine effects of Saharan dust on the radiative fluxes and heating/cooling rates in the atmosphere. Cases are treated for cloud-free and overcast conditions over the ocean ...

Toby N. Carlson; Stanley G. Benjamin

1980-01-01T23:59:59.000Z

87

The Dust Accelerator Facility of the Colorado Center for Lunar Dust and Atmospheric Studies  

Science Conference Proceedings (OSTI)

The NASA Lunar Institute's Colorado Center for Lunar Dust and Atmospheric Studies has recently completed the construction of a new experimental facility to study hypervelocity dust impacts. The installation includes a 3 MV Pelletron, accelerating small particles in the size range of 0.1 to few microns to velocities in the range of 1 to 100 km/s. Here we report the capabilities of our facility, and the results of our first experiments.

Horanyi, M.; Colette, A.; Drake, K.; Gruen, E.; Kempf, S.; Munsat, T.; Robertson, S.; Shu, A.; Sternovsky, Z.; Wang, X. [NASA Lunar Science Institute Colorado Center for Lunar Dust and Atmospheric Studies University of Colorado, Boulder, CO, 80309 (United States)

2011-11-29T23:59:59.000Z

88

Hamiltonian spacetime dynamics with a spherical null-dust shell  

E-Print Network (OSTI)

We consider the Hamiltonian dynamics of spherically symmetric Einstein gravity with a thin null-dust shell, under boundary conditions that fix the evolution of the spatial hypersurfaces at the two asymptotically flat infinities of a Kruskal-like manifold. The constraints are eliminated via a Kuchar-type canonical transformation and Hamiltonian reduction. The reduced phase space $\\tilde\\Gamma$ consists of two disconnected copies of $R^4$, each associated with one direction of the shell motion. The right-moving and left-moving test shell limits can be attached to the respective components of right-hand-side and left-hand-side masses as configuration variables provides a global canonical chart on each component of $\\tilde\\Gamma$, and renders the Hamiltonian simple, but encodes the shell dynamics in the momenta in a convoluted way. Choosing the shell curvature radius and the "interior" mass as configuration variables renders the shell dynamics transparent in an arbitrarily specifiable stationary gauge "exterior" ...

Louko, J; Friedman, J L; Louko, Jorma; Whiting, Bernard F.; Friedman, John L.

1998-01-01T23:59:59.000Z

89

3 MV hypervelocity dust accelerator at the Colorado Center for Lunar Dust and Atmospheric Studies  

Science Conference Proceedings (OSTI)

A hypervelocity dust accelerator for studying micrometeorite impacts has been constructed at the Colorado Center for Lunar Dust and Atmospheric Studies (CCLDAS) at the University of Colorado. Based on the Max-Planck-Instituet fuer Kernphysik (MPI-K) accelerator, this accelerator is capable of emitting single particles of a specific mass and velocity selected by the user. The accelerator consists of a 3 MV Pelletron generator with a dust source, four image charge pickup detectors, and two interchangeable target chambers: a large high-vacuum test bed and an ultra-high vacuum impact study chamber. The large test bed is a 1.2 m diameter, 1.5 m long cylindrical vacuum chamber capable of pressures as low as 10{sup -7} torr while the ultra-high vacuum chamber is a 0.75 m diameter, 1.1 m long chamber capable of pressures as low as 10{sup -10} torr. Using iron dust of up to 2 microns in diameter, final velocities have been measured up to 52 km/s. The spread of the dust particles and the effect of electrostatic focusing have been measured using a long exposure CCD and a quartz target. Furthermore, a new technique of particle selection is being developed using real time digital filtering techniques. Signals are digitized and then cross-correlated with a shaped filter, resulting in a suppressed noise floor. Improvements over the MPI-K design, which include a higher operating voltage and digital filtering for detection, increase the available parameter space of dust emitted by the accelerator. The CCLDAS dust facility is a user facility open to the scientific community to assist with instrument calibrations and experiments.

Shu, Anthony; Horanyi, Mihaly; Kempf, Sascha; Thomas, Evan [Colorado Center for Lunar Dust and Atmospheric Studies, Boulder, Colorado 80303 (United States); Department of Physics, University of Colorado, Boulder, Colorado 80309 (United States); Laboratory for Atmospheric and Space Physics, 1234 Innovation Drive, Boulder, Colorado 80303 (United States); Collette, Andrew; Drake, Keith; Northway, Paige [Colorado Center for Lunar Dust and Atmospheric Studies, Boulder, Colorado 80303 (United States); Laboratory for Atmospheric and Space Physics, 1234 Innovation Drive, Boulder, Colorado 80303 (United States); Gruen, Eberhard [Colorado Center for Lunar Dust and Atmospheric Studies, Boulder, Colorado 80303 (United States); MPI fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Mocker, Anna [Colorado Center for Lunar Dust and Atmospheric Studies, Boulder, Colorado 80303 (United States); MPI fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); IRS, Universitaet Stuttgart, Pfaffenwaldring 31, D-70569 Stuttgart (Germany); Munsat, Tobin [Colorado Center for Lunar Dust and Atmospheric Studies, Boulder, Colorado 80303 (United States); Department of Physics, University of Colorado, Boulder, Colorado 80309 (United States); Srama, Ralf [MPI fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); IRS, Universitaet Stuttgart, Pfaffenwaldring 31, D-70569 Stuttgart (Germany); and others

2012-07-15T23:59:59.000Z

90

Numerical study of an electrostatic plasma sheath containing two species of charged dust particles  

Science Conference Proceedings (OSTI)

A multi-fluid model is used to study the dynamics of a dusty plasma sheath consists of electrons, ions, and two species of charged dust particles, i.e., nano-size and micron-size particles. It is found that, when the sheath is dominated by the nano-size dust grains, spatially periodic fluctuations are developed in the profiles of the sheath potential, and the number density and velocity of the plasma and dust particles. Due to inertial effects, the fluctuations in the parameters of the micron-size grains are much lower than those of the other parameters. The competition between the electric and ion drag forces plays the primary role in development of the fluctuations. The spatial period of the fluctuations is approximately a few Debye lengths and their amplitude depends on the plasma and dust parameters. The fluctuations are reduced by the increase in the radius, mass density, and Mach number of the nano-size particles, as well as the density and Mach number of the ions. But, they are enhanced by the increase in the plasma number density and the electron temperature. The sheath thickness demonstrates a non-monotonic behavior against variation of the nanoparticle parameters, i.e., it first decreases quickly, shows a minimum, and then increases. However, the sheath width always decreases with the plasma number density and ion Mach number, while grows linearly with the electron temperature.

Foroutan, G. [Physics Department, Faculty of Science, Sahand University of Technology, 51335-1996 Tabriz (Iran, Islamic Republic of); Akhoundi, A. [Nanostructure Material Research Center, Sahand University of Technology, 51335-1996 Tabriz (Iran, Islamic Republic of)

2012-10-01T23:59:59.000Z

91

Milky Way Tomography IV: Dissecting Dust  

SciTech Connect

We use SDSS photometry of 73 million stars to simultaneously obtain best-fit main-sequence stellar energy distribution (SED) and amount of dust extinction along the line of sight towards each star. Using a subsample of 23 million stars with 2MASS photometry, whose addition enables more robust results, we show that SDSS photometry alone is sufficient to break degeneracies between intrinsic stellar color and dust amount when the shape of extinction curve is fixed. When using both SDSS and 2MASS photometry, the ratio of the total to selective absorption, R{sub V}, can be determined with an uncertainty of about 0.1 for most stars in high-extinction regions. These fits enable detailed studies of the dust properties and its spatial distribution, and of the stellar spatial distribution at low Galactic latitudes (|b| < 30{sup o}). Our results are in good agreement with the extinction normalization given by the Schlegel et al. (1998, SFD) dust maps at high northern Galactic latitudes, but indicate that the SFD extinction map appears to be consistently overestimated by about 20% in the southern sky, in agreement with recent study by Schlafly et al. (2010). The constraints on the shape of the dust extinction curve across the SDSS and 2MASS bandpasses disfavor the reddening law of O'Donnell (1994), but support the models by Fitzpatrick (1999) and Cardelli et al. (1989). For the latter, we find a ratio of the total to selective absorption to be R{sub V} = 3.0 {+-} 0.1(random) {+-} 0.1 (systematic) over most of the high-latitude sky. At low Galactic latitudes (|b| < 5{sup o}), we demonstrate that the SFD map cannot be reliably used to correct for extinction because most stars are embedded in dust, rather than behind it, as is the case at high Galactic latitudes. We analyze three-dimensional maps of the best-fit R{sub V} and find that R{sub V} = 3.1 cannot be ruled out in any of the ten SEGUE stripes at a precision level of {approx} 0.1 - 0.2. Our best estimate for the intrinsic scatter of R{sub V} in the regions probed by SEGUE stripes is {approx} 0.2. We introduce a method for efficient selection of candidate red giant stars in the disk, dubbed 'dusty parallax relation', which utilizes a correlation between distance and the extinction along the line of sight. We make these best-fit parameters, as well as all the input SDSS and 2MASS data, publicly available in a user-friendly format. These data can be used for studies of stellar number density distribution, the distribution of dust properties, for selecting sources whose SED differs from SEDs for high-latitude main sequence stars, and for estimating distances to dust clouds and, in turn, to molecular gas clouds.

Berry, Michael; /Washington U., Seattle, Astron. Dept. /Rutgers U., Piscataway; Ivezic, Zeljko; /Washington U., Seattle, Astron. Dept.; Sesar, Branimir; /Caltech; Juric, Mario; /Harvard U., Phys. Dept.; Schlafly, Edward F.; /Harvard-Smithsonian Ctr. Astrophys.; Bellovary, Jillian; /Michigan U.; Finkbeiner, Douglas; /Harvard-Smithsonian Ctr. Astrophys.; Vrbanec, Dijana; /Zagreb U.; Beers, Timothy C.; /Natl. Solar Observ., Tucson; Brooks, Keira J.; /Washington U., Seattle, Astron. Dept.; Schneider, Donald P.; /Penn State U. /Washington U., Seattle, Astron. Dept.

2011-11-01T23:59:59.000Z

92

The Dust Tail of Asteroid (3200) Phaethon  

E-Print Network (OSTI)

We report the discovery of a comet-like tail on asteroid (3200) Phaethon when imaged at optical wavelengths near perihelion. In both 2009 and 2012, the tail appears >=350" (2.5x10^8 m) in length and extends approximately in the projected anti-solar direction. We interpret the tail as being caused by dust particles accelerated by solar radiation pressure. The sudden appearance and the morphology of the tail indicate that the dust particles are small, with an effective radius ~1 micrometer and a combined mass ~3x10^5 kg. These particles are likely products of thermal fracture and/or desiccation cracking under the very high surface temperatures (~1000 K) experienced by Phaethon at perihelion. The existence of the tail confirms earlier inferences about activity in this body based on the detection of anomalous brightening. Phaethon, the presumed source of the Geminid meteoroids, is still active.

Jewitt, David; Agarwal, Jessica

2013-01-01T23:59:59.000Z

93

ALPHA ATTENUATION DUE TO DUST LOADING  

SciTech Connect

Previous studies had been done in order to show the attenuation of alpha particles in filter media. These studies provided an accurate correction for this attenuation, but there had not yet been a study with sufficient results to properly correct for attenuation due to dust loading on the filters. At the Savannah River Site, filter samples are corrected for attenuation due to dust loading at 20%. Depending on the facility the filter comes from and the duration of the sampling period, the proper correction factor may vary. The objective of this study was to determine self-absorption curves for each of three counting instruments. Prior work indicated significant decreases in alpha count rate (as much as 38%) due to dust loading, especially on filters from facilities where sampling takes place over long intervals. The alpha count rate decreased because of a decrease in the energy of the alpha. The study performed resulted in a set of alpha absorption curves for each of three detectors. This study also took into account the affects of the geometry differences in the different counting equipment used.

Dailey, A; Dennis Hadlock, D

2007-08-09T23:59:59.000Z

94

Spatial distribution of the interplanetary dust deduced by infrared observations  

Science Conference Proceedings (OSTI)

IR observations of the interplanetary dust performed by the ZIP rocket experiment are analyzed, focusing on the effect of experimental errors on the inversion procedure previously used to obtain the spatial distribution of the dust. Numerical simulation shows that the experimental errors are too large to reveal deviations of the dust density from a simple power-law radial distribution. The accuracy which would be required in future experiments is estimated. 9 refs.

De Bernardis, P.; Feminella, F.; Moreno, G. (Roma I Universita, Rome (Italy))

1991-03-01T23:59:59.000Z

95

Radiative Forcing of Climate By Ice-Age Atmospheric Dust  

E-Print Network (OSTI)

During glacial periods, dust deposition rates and inferred atmospheric concentrations were globally much higher than present. According to recent model results, the large enhancement of atmospheric dust content at the last glacial maximum (LGM) can be explained only if increases in the potential dust source areas are taken into account. Such increases are to be expected, due to e#ects of low precipitation and low atmospheric (CO 2 ) on plant growth. Here the modelled three-dimensional dust fields from Mahowald et al. and modelled seasonally varying surface-albedo fields derived in a parallel manner, are used to quantify the mean radiative forcing due to modern (non-anthropogenic) and LGM dust. The e#ect of mineralogical provenance on the radiative properties of the dust is taken into account, as is the range of optical properties associated with uncertainties about the mixing state of the dust particles. The high-latitude (poleward of 45#) mean change in forcing (LGM minus modern) is estimated to be small (--0.9 to +0.2 W m ), especially when compared to nearly --20 W m due to reflection from the extended ice sheets. Although the net e#ect of dust over ice sheets is a positive forcing (warming), much of the simulated high-latitude dust was not over the ice sheets, but over unglaciated regions close to the expanded dust source region in central Asia. In the tropics the change in forcing is estimated to be overall negative, and of similarly large magnitude (--2.2 to --3.2 W m ) to the radiative cooling e#ect of low atmospheric (CO 2 ). Thus, the largest long-term climatic e#ect of the LGM dust is likely to have been a cooling of the tropics. Low tropical sea-surface temperatures, low atmospheric (CO 2 ) and high atmospheric dust loading may be mutually reinforcin...

T. Claquin; C. Roelandt; K.E. Kohfeld; S.P. Harrison; I. Tegen; I.C. Prentice; Y. Balkanski; Prentice Æ Y. Balkanski; G. Bergametti; Æ N. Mahowald; Æ M. Schulz; M. Schulz; Æ K. E. Kohfeld; Æ K. E. Kohfeld; C. Roelandt; C. Roelandt; Æ S. P. Harrison; Æ S. P. Harrison; Æ S. P. Harrison; G. Bergametti; H. Rodhe; Æ H. Rodhe; M. Hansson; M. Hansson; N. Mahowald; N. Mahowald

2003-01-01T23:59:59.000Z

96

Dust acoustic shock waves in two temperatures charged dusty grains  

Science Conference Proceedings (OSTI)

The reductive perturbation method has been used to derive the Korteweg-de Vries-Burger equation and modified Korteweg-de Vries-Burger for dust acoustic shock waves in a homogeneous unmagnetized plasma having electrons, singly charged ions, hot and cold dust species with Boltzmann distributions for electrons and ions in the presence of the cold (hot) dust viscosity coefficients. The behavior of the shock waves in the dusty plasma has been investigated.

El-Shewy, E. K. [Theoretical Physics Group, Faculty of Science, Mansoura University, Mansoura (Egypt); Science and Arts College in Al-Rass, Physics Department, Qassim University, Al-Rass Province (Saudi Arabia); Abdelwahed, H. G. [Theoretical Physics Group, Faculty of Science, Mansoura University, Mansoura (Egypt); College of Science and Humanitarian Studies, Physics Department, Alkharj University, Al-kharj (Saudi Arabia); Elmessary, M. A. [Engineering Mathematics and Physics Department, Faculty of Engineering, Mansoura University, Mansoura (Egypt)

2011-11-15T23:59:59.000Z

97

Recovering Zinc and Lead from Electric Arc Furnace Dust  

Science Conference Proceedings (OSTI)

Aug 1, 2000 ... Non-member price: 25.00. TMS Student Member price: 10.00. Product In Stock. Description Increasing amounts of electric arc furnace dust ...

98

Dust-induced instability in a rotating plasma  

SciTech Connect

The effect of immobile dust on stability of a magnetized rotating plasma is analyzed. In the presence of dust, a term containing an electric field appears in the one-fluid equation of plasma motion. This electric field leads to an instability of the magnetized rotating plasma called the dust-induced rotational instability (DRI). The DRI is related to the charge imbalance between plasma ions and electrons introduced by the presence of charged dust. In contrast to the well-known magnetorotational instability requiring the decreasing radial profile of the plasma rotation frequency, the DRI can appear for an increasing rotation frequency profile.

Mikhailovskii, A. B.; Vladimirov, S. V.; Lominadze, J. G.; Tsypin, V. S.; Churikov, A. P.; Erokhin, N. N.; Galvao, R. M. O. [Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, 1, Kurchatov Sq., Moscow 123182 (Russian Federation); School of Physics, University of Sydney, Sydney, N.S.W. 2006 (Australia); Kharadze Abastumani National Astrophysical Observatory, 2a, Kazbegi Ave., Tbilisi 0160 (Georgia); Brazilian Center for Physics Research, Rua Xavier Sigaud, 150, 22290-180, Rio de Janeiro (Brazil); Syzran Branch of Samara Technical University, 45, Sovetskaya Str., Syzran, Samara Region 446001 (Russian Federation); Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, 1, Kurchatov Sq., Moscow 123182 (Russian Federation); Physics Institute, University of Sao Paulo, Cidade Universitaria, 05508-900, Sao Paulo, Brazil and Brazilian Center for Physics Research, Rua Xavier Sigaud, 150, 22290-180, Rio de Janeiro (Brazil)

2008-01-15T23:59:59.000Z

99

ESP Dust Recovery Process Test Works, Plant Trial, Commissioning ...  

Science Conference Proceedings (OSTI)

Most of the volatile arsenic will report to Isasmelt Electrostatic Precipitator (ESP) or Waste Heat Boiler dusts where it will form a re-circulating load within the ...

100

Secondary Electron Emission from Dust and Its Effect on Charging  

Science Conference Proceedings (OSTI)

Hydrogen plasma is produced in a plasma chamber by striking discharge between incandescent tungsten filaments and the permanent magnetic cage [1], which is grounded. The magnetic cage has a full line cusped magnetic field geometry used to confine the plasma elements. A cylindrical Langmuir probe is used to study the plasma parameters in various discharge conditions. The charge accumulated on the dust particles is calculated using the capacitance model and the dust current is measured by the combination of a Faraday cup and an electrometer at different discharge conditions. It is found Secondary electron emission from dust having low emission yield effects the charging of dust particles in presence of high energetic electrons.

Saikia, B. K.; Kakati, B.; Kausik, S. S. [Centre of Plasma Physics, Institute for Plasma Research, Nazirakhat, Sonapur-782402, Assam (India); Bandyopadhyay, M. [ITER-India, Institute for Plasma Research, Bhat, Gandhinagar-382 428 (India)

2011-11-29T23:59:59.000Z

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Heterogeneous Reactions on Mineral Dust: Surface Reactions of...  

NLE Websites -- All DOE Office Websites (Extended Search)

Reactions on Mineral Dust: Surface Reactions of Sulfur Dioxide, Ozone, Nitric and Acetic Acid on Oxide and Carbonate Particles Speaker(s): Vicki Grassian Date: June 14,...

102

Dust in the Indoor Environment: Physical and Chemical Changes...  

NLE Websites -- All DOE Office Websites (Extended Search)

Hottinger said: "Settled dust on hot surfaces above 70 degrees Celsius results in distillation products having irritating effect on mucous membranes, fairly equal to the effect...

103

THE DUST BUDGET OF THE SMALL MAGELLANIC CLOUD: ARE ASYMPTOTIC GIANT BRANCH STARS THE PRIMARY DUST SOURCE AT LOW METALLICITY?  

Science Conference Proceedings (OSTI)

We estimate the total dust input from the cool evolved stars in the Small Magellanic Cloud, using the 8 {mu}m excess emission as a proxy for the dust-production rate (DPR). We find that asymptotic giant branch (AGB) and red supergiant (RSG) stars produce (8.6-9.5) Multiplication-Sign 10{sup -7} M{sub Sun} yr{sup -1} of dust, depending on the fraction of far-infrared sources that belong to the evolved star population (with 10%-50% uncertainty in individual DPRs). RSGs contribute the least (budget, this suggests that dust must grow in the ISM or be formed by another unknown mechanism.

Boyer, M. L.; Gordon, K. D.; Meixner, M.; Sargent, B. A. [STScI, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Srinivasan, S. [UPMC-CNRS UMR7095, Institut d'Astrophysique de Paris, F-75014 Paris (France); Riebel, D. [Department of Physics and Astronomy, The Johns Hopkins University, Homewood Campus, Baltimore, MD 21218 (United States); McDonald, I. [Jodrell Bank Centre for Astrophysics, Alan Turing Building, University of Manchester, Manchester M13 9PL (United Kingdom); Van Loon, J. Th. [Astrophysics Group, Lennard-Jones Laboratories, Keele University, Staffordshire ST5 5BG (United Kingdom); Clayton, G. C. [Department of Physics and Astronomy, Louisiana State University, 233-A Nicholson Hall, Tower Dr., Baton Rouge, LA 70803-4001 (United States); Sloan, G. C., E-mail: mboyer@stsci.edu [Astronomy Department, Cornell University, Ithaca, NY 14853-6801 (United States)

2012-03-20T23:59:59.000Z

104

Episodic Dust Events of Utah’s Wasatch Front and Adjoining Region  

Science Conference Proceedings (OSTI)

Episodic dust events cause hazardous air quality along Utah’s Wasatch Front and dust loading of the snowpack in the adjacent Wasatch Mountains. This paper presents a climatology of episodic dust events of the Wasatch Front and adjoining region ...

W. James Steenburgh; Jeffrey D. Massey; Thomas H. Painter

2012-09-01T23:59:59.000Z

105

Evolution of Dust Extinction and Supernova Cosmology  

E-Print Network (OSTI)

We have made a quantitative calculation for the systematic evolution of average extinction by interstellar dust in host galaxies of high-redshift Type Ia supernovae, by using a realistic model of photometric and chemical evolution of galaxies and supernova rate histories in various galaxy types. We find that average B band extinction at z \\sim 0.5 is typically 0.1-0.2 mag larger than present, under a natural assumption that dust optical depth is proportional to gas column density and gas metallicity. This systematic evolution causes average reddening with E(B-V) \\sim 0.025-0.05 mag with the standard extinction curve, and this is comparable with the observational uncertainty of the reddening of high-redshift supernovae. Therefore, our result does not contradict the observations showing no significant reddening in high-z supernovae. However, the difference in apparent magnitude between an open universe and a \\Lambda-dominated flat universe is only \\sim 0.2 mag at z \\sim 0.5, and hence this systematic evolution of extinction should be taken into account in a reliable measurement of cosmological parameters. Considering this uncertainty, we show that it is difficult to discriminate between an open and \\Lambda-dominated flat cosmologies from the current data.

Tomonori Totani; Chiaki Kobayashi

1999-10-04T23:59:59.000Z

106

DUST-DRIVEN WIND FROM DISK GALAXIES  

SciTech Connect

We study gaseous outflows from disk galaxies driven by radiation pressure on dust grains. We include the effect of bulge and dark matter halo and show that the existence of such an outflow implies a maximum value of disk mass-to-light ratio. We show that the terminal wind speed is proportional to the disk rotation speed in the limit of a cold gaseous outflow, and that in general there is a contribution from the gas sound speed. Using the mean opacity of dust grains and the evolution of the luminosity of a simple stellar population, we then show that the ratio of the wind terminal speed (v{sub {infinity}}) to the galaxy rotation speed (v{sub c}) ranges between 2 and 3 for a period of {approx}10 Myr after a burst of star formation, after which it rapidly decays. This result is independent of any free parameter and depends only on the luminosity of the stellar population and the relation between disk and dark matter halo parameters. We briefly discuss the possible implications of our results.

Sharma, Mahavir; Nath, Biman B. [Raman Research Institute, Sadashiva Nagar, Bangalore 560080 (India); Shchekinov, Yuri, E-mail: mahavir@rri.res.in, E-mail: biman@rri.res.in, E-mail: yus@sfedu.ru [Department of Physics, Southern Federal University, Rostov on Don 344090 (Russian Federation)

2011-08-01T23:59:59.000Z

107

Two-Component Dust in Spherically Symmetric Motion  

E-Print Network (OSTI)

Two components of spherically symmetric, inhomogeneous dust penetrating each other are introduced as a generalization of the well-known Tolman-Bondi dust solution. The field equations of this model are formulated and general properties are discussed. inhomogeneous Special solutions with additional symmetries - an extra Killing- or homothetic vector - and their matching to the corresponding Tolman-Bondi solution are investigated.

Haager, G

1997-01-01T23:59:59.000Z

108

Two-Component Dust in Spherically Symmetric Motion  

E-Print Network (OSTI)

Two components of spherically symmetric, inhomogeneous dust penetrating each other are introduced as a generalization of the well-known Tolman-Bondi dust solution. The field equations of this model are formulated and general properties are discussed. inhomogeneous Special solutions with additional symmetries - an extra Killing- or homothetic vector - and their matching to the corresponding Tolman-Bondi solution are investigated.

Gernot Haager

1997-05-02T23:59:59.000Z

109

Dust en-route to Jupiter and the Galilean satellites  

E-Print Network (OSTI)

Spacecraft investigations during the last ten years have vastly improved our knowledge about dust in the Jovian system. All Galilean satellites, and probably all smaller satellites as well, are sources of dust in the Jovian system. In-situ measurements with the dust detectors on board the Ulysses and Galileo spacecraft have for the first time demonstrated the electromagnetic interaction of charged dust grains with the interplanetary magnetic field and with a planetary magnetosphere. Jupiter's magnetosphere acts as a giant mass-velocity spectrometer for charged 10-nanometer dust grains. These dust grains are released from Jupiter's moon Io with typical rate of 1 kg s^1. The dust streams probe the plasma conditions in the Io plasma torus and can be used as a potential monitor of Io's volcanic plume activity. The other Galilean satellites are surrounded by tenuous impact-generated clouds of mostly sub-micrometer ejecta grains. Galileo measurements have demonstrated that impact-ejecta derived from hypervelocity impacts onto satellites are the major -- if not the only -- constituent of dusty planetary rings. We review the in-situ dust measurements at Jupiter and give an update of most recent results.

Harald Krueger; Eberhard Gruen

2002-05-28T23:59:59.000Z

110

Constraining oceanic dust deposition using surface ocean dissolved Al  

E-Print Network (OSTI)

Constraining oceanic dust deposition using surface ocean dissolved Al Qin Han,1 J. Keith Moore,1; accepted 7 December 2007; published 12 April 2008. [1] We use measurements of ocean surface dissolved Al (DEAD) model to constrain dust deposition to the oceans. Our Al database contains all available

Moore, Keith

111

The Influence of Dust on the Absorptivity of Radiant Barriers  

E-Print Network (OSTI)

The purpose of this project was to model and quantify the increase of the absorptivity of radiant barriers caused by the accumulation of dust on the surface of radiant barriers. This research was the continuation of a previous work by the author at Texas A&M University in which a radiation energy balance inside the attic enclosure was developed. The particles were considered as flat, circular planes, all having the same radii. That early model showed that there was a linear relationship between the fraction of area of the foil covered by dust and the mean absorptivity of the dusty radiant barrier. In the present work, it was found that the assumption of treating the dust particles as plane circles, underestimated the effective area of the particles by about 20%. Experimental measurements indicated that dust particles achieved the same temperature as the radiant barrier. The new model used the linear relationship just described, and simulated the dust particles as flat circular planes having random radii and laying in random locations within the radiant barrier surface. The new model calculated the fraction of radiant barrier area covered by particles using a digital array in which the clean barrier was represented as zeroes and the dust particles were represented as a set of ones appropriately dimensioned inside the array. The experimentation used natural dust and Arizona Road Test Dust. Using an infrared emissometer, the emissivities (absorptivities) of the clean and dusty barriers were measured and using an electronic scale, the dust loading was measured. An electron microscope was used to experimentally find the fraction of radiant barrier covered by the dust particles to correlate the experimentally found absorptivity with the experimentally found fraction of dust coverage. The limited experimental data available were also used to correlate the absorptivity of the dusty radiant barrier with the time of dust accumulation and the location of the barrier inside the attic. A linear relationship between the absorptivity and the time of dust accumulation was found that can be applied to predict future barrier effectiveness based upon the rate of dust accumulation for a given location.

Noboa, Homero L.

1993-08-01T23:59:59.000Z

112

INTERSTELLAR DUST MODULE FOR THE ESA METEOROID MODEL  

E-Print Network (OSTI)

The ESA meteoroid model predicts impacts of meteoroids in the mass range between 10 ?18 to 10 0 g on spacecraft surfaces. It covers heliocentric distances from 0.3 to 20 AU. Measurements of the dust detector on board the highly successful joint ESA/NASA mission Ulysses have shown, that the flux of meteoroids with masses between 10 ?15 and 10 ?12 g is, at least in the outer Solar System, dominated by interstellar dust grains that traverse the Solar System as it travels through the local interstellar cloud. We present a simple semi-analytic interstellar dust model that can easily be included in the ESA meteoroid model, together with a more precise determination of the flux direction of the interstellar dust stream. The model is based on the assumption that interstellar dust dynamics have two effects: solar gravitation and radiation pressure determines the spatial distribution, and Lorentz-interaction of the charged particles creates a temporal variation. 1.

R. Jehn; N. Altobelli; V. Dikarev; E. Grün

2001-01-01T23:59:59.000Z

113

The ecology of dust: local- to global-scale perspectives  

SciTech Connect

Emission and redistribution of dust due to wind erosion in drylands drives major biogeochemical dynamics and provides important aeolian environmental connectivity at scales from individual plants up to the global scale. Yet, perhaps because most relevant research on aeolian processes has been presented in a geosciences rather than ecological context, most ecological studies do not explicitly consider dust-driven processes. To bridge this disciplinary gap, we provide a general overview of the ecological importance of dust, examine complex interactions between wind erosion and ecosystem dynamics from the plant-interspace scale to regional and global scales, and highlight specific examples of how disturbance affects these interactions and their consequences. Changes in climate and intensification of land use will both likely lead to increased dust production. To address these challenges, environmental scientists, land managers and policy makers need to more explicitly consider dust in resource management decisions.

Whicker, Jeffrey J [Los Alamos National Laboratory; Field, Jason P [UA; Belnap, Jayne [NON LANL; Breshears, David D [UA; Neff, Jason [CU; Okin, Gregory S [UCLA; Painter, Thomas H [UNIV OF ARIZONA; Ravi, Sujith [UNIV OF ARIZONA; Reheis, Marith C [UCLA; Reynolds, Richard L [NON LANL

2009-01-01T23:59:59.000Z

114

THE ORIGIN OF DUST IN THE EARLY UNIVERSE: PROBING THE STAR FORMATION HISTORY OF GALAXIES BY THEIR DUST CONTENT  

SciTech Connect

Two distinct scenarios for the origin of the {approx}4 x 10{sup 8} M{sub sun} of dust observed in the high-redshift (z = 6.4) quasar J1148+5251 have been proposed. The first assumes that this galaxy is much younger than the age of the universe at that epoch so that only supernovae (SNe) could have produced this dust. The second scenario assumes a significantly older galactic age, so that the dust could have formed in lower-mass asymptotic giant branch (AGB) stars. Presenting new integral solutions for the chemical evolution of metals and dust in galaxies, we offer a critical evaluation of these two scenarios and observational consequences that can discriminate between the two. We show that AGB stars can produce the inferred mass of dust in this object, however, the final mass of surviving dust depends on the galaxy's star formation history (SFH). In general, SNe cannot produce the observed amount of dust unless the average SN event creates over {approx}2 M{sub sun} of dust in its ejecta. However, special SFHs can be constructed in which SNe can produce the inferred dust mass with a reasonable average dust yield of {approx}0.15 M{sub sun}. The two scenarios propose different origins for the galaxy's spectral energy distribution, different star formation efficiencies and stellar masses, and consequently different comoving number densities of J1148+5251-type hyperluminous infrared (IR) objects. The detection of diagnostic mid-IR fine structure lines and more complete surveys determining the comoving number density of these objects can discriminate between the two scenarios.

Dwek, Eli [Observational Cosmology Lab, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Cherchneff, Isabelle, E-mail: eli.dwek@nasa.gov, E-mail: isabelle.cherchneff@unibas.ch [Department Physik, Universitaet Basel, CH-4056 Basel (Switzerland)

2011-02-01T23:59:59.000Z

115

Energy conditions, traversable wormholes and dust shells  

E-Print Network (OSTI)

Firstly, we review the pointwise and averaged energy conditions, the quantum inequality and the notion of the ``volume integral quantifier'', which provides a measure of the ``total amount'' of energy condition violating matter. Secondly, we present a specific metric of a spherically symmetric traversable wormhole in the presence of a generic cosmological constant, verifying that the null and the averaged null energy conditions are violated, as was to be expected. Thirdly, a pressureless dust shell is constructed around the interior wormhole spacetime by matching the latter geometry to a unique vacuum exterior solution. In order to further minimize the usage of exotic matter, we then find regions where the surface energy density is positive, thereby satisfying all of the energy conditions at the junction surface. An equation governing the behavior of the radial pressure across the junction surface is also deduced. Lastly, taking advantage of the construction, specific dimensions of the wormhole, namely, the t...

Lobo, F S N

2004-01-01T23:59:59.000Z

116

Carbon dioxide sequestration in cement kiln dust through mineral carbonation  

Science Conference Proceedings (OSTI)

Carbon sequestration through the formation of carbonates is a potential means to reduce CO{sub 2} emissions. Alkaline industrial solid wastes typically have high mass fractions of reactive oxides that may not require preprocessing, making them an attractive source material for mineral carbonation. The degree of mineral carbonation achievable in cement kiln dust (CKD) under ambient temperatures and pressures was examined through a series of batch and column experiments. The overall extent and potential mechanisms and rate behavior of the carbonation process were assessed through a complementary set of analytical and empirical methods, including mass change, thermal analysis, and X-ray diffraction. The carbonation reactions were carried out primarily through the reaction of CO{sub 2} with Ca(OH){sub 2}, and CaCO{sub 3} was observed as the predominant carbonation product. A sequestration extent of over 60% was observed within 8 h of reaction without any modifications to the waste. Sequestration appears to follow unreacted core model theory where reaction kinetics are controlled by a first-order rate constant at early times; however, as carbonation progresses, the kinetics of the reaction are attenuated by the extent of the reaction due to diffusion control, with the extent of conversion never reaching completion. 35 refs., 3 figs., 1 tab.

Deborah N. Huntzinger; John S. Gierke; S. Komar Kawatra; Timothy C. Eisele; Lawrence L. Sutter [University of Michigan, Ann Arbor, MI (United States). Department of Civil and Environmental Engineering

2009-03-15T23:59:59.000Z

117

A new method to generate dust with astrophysical properties  

SciTech Connect

In interstellar and interplanetary space, the size distribution and composition of dust grains play an important role. For example, dust grains determine optical and ultraviolet extinction levels in astronomical observations, dominate the cooling rate of our Galaxy, and sets the thermal balance and radiative cooling rates in molecular clouds, which are the birth place of stars. Dust grains are also a source of damage and failure to space hardware and thus present a hazard to space flight. To model the size distribution and composition of dust grains, and their effect in the above scenarios, it is vital to understand the mechanism of dust-shock interaction. We demonstrate a new experiment which employs a laser to subject dust grains to pressure spikes similar to those of colliding astrophysical dust, and which accelerates the grains to astrophysical velocities. The new method generates much larger data sets than earlier methods; we show how large quantities (thousands) of grains are accelerated at once, rather than accelerating individual grains, as is the case of earlier methods using electric fields.

Hansen, J F; van Breugel, W; Bringa, E M; Graham, G A; Remington, B A; Taylor, E A; Tielens, A G

2010-04-21T23:59:59.000Z

118

Influence of Dust on the Emissivity of Radiant Barriers  

E-Print Network (OSTI)

A model of the radiant heat transfer in attics containing dusty radiant barriers was developed. The geometrical model was a triangular enclosure in which the temperatures of the enclosing surfaces were known. The dust particles were simulated as areas of diameter equal to the mean diameter of the real dust to be analyzed and an emissivity substantially larger than the emissivity of the radiant barrier. Several shape factors were calculated using shape factor algebra, including a procedure to find the shape factor between a small rectangle and a triangular surface perpendicular to the rectangular plane. The thermal model was developed using the "Net Radiation Method" in which the net heat exchange between the surfaces surrounding the enclosure was found by solving a system of equations that has as many equations as the number of surfaces involved in the calculations. This led to the necessity of solving a very large system of equations in order to account for the dust particles in a representative amount. The solution of the system of equations provided the heat flux for each element of the enclosure. Finally, replacing the radiant barrier and the dust particles for an equivalent surface corresponding to the dusty radiant barrier provided the means to calculate the emissivity of this dusty radiant barrier. The theoretical model was tested to assess its validity. The experimentation was carried out using a reflection emissometer to measure the increase of the emissivity of aluminum radiant barrier when known quantities of dust were artificially applied to it. The experimental results showed good agreement with the theoretical model. A linear relationship between the emissivity and the area of dust coverage was found. The simple relation developed can be used in future research which still has to deal with the determination of the area of dust coverage by using the geometrical model of dust superposition or other statistical model to simulate the random location of random size dust particles over the radiant barrier.

Noboa, Homero L.

1991-12-01T23:59:59.000Z

119

Sensitivity Studies of Dust Ice Nuclei Effect on Cirrus Clouds with the Community Atmosphere Model CAM5  

SciTech Connect

In this study the effect of dust aerosol on upper tropospheric cirrus clouds through heterogeneous ice nucleation is investigated in the Community Atmospheric Model version 5 (CAM5) with two ice nucleation parameterizations. Both parameterizations consider homogeneous and heterogeneous nucleation and the competition between the two mechanisms in cirrus clouds, but differ significantly in the number concentration of heterogeneous ice nuclei (IN) from dust. Heterogeneous nucleation on dust aerosol reduces the occurrence frequency of homogeneous nucleation and thus the ice crystal number concentration in the Northern Hemisphere (NH) cirrus clouds compared to simulations with pure homogeneous nucleation. Global and annual mean shortwave and longwave cloud forcing are reduced by up to 2.0 ± 0.1 W m?2 (1? uncertainty) and 2.4 ± 0.1 W m?2, respectively due to the presence of dust IN, with the net cloud forcing change of ?0.40 ± 0.20 W m?2. Comparison of model simulations with in situ aircraft data obtained in NH mid-latitudes suggests that homogeneous ice nucleation may play an important role in the ice nucleation at these regions with temperatures of 205–230 K. However, simulations overestimate observed ice crystal number concentrations in the tropical tropopause regions with temperatures of 190–205 K, and overestimate the frequency of occurrence of high ice crystal number concentration (> 200 L?1) and underestimate the frequency of low ice crystal number concentration (< 30 L?1) at NH mid-latitudes. These results highlight the importance of quantifying the number concentrations and properties of heterogeneous IN (including dust aerosol) in the upper troposphere from the global perspective.

Liu, Xiaohong; Shi, Xiangjun; Zhang, Kai; Jensen, Eric; Gettelman, A.; Barahona, Donifan; Nenes, Athanasios; Lawson, Paul

2012-12-19T23:59:59.000Z

120

Microsoft Word - Natural Gas JIM REVISED 7-21-04pm#.doc  

NLE Websites -- All DOE Office Websites (Extended Search)

new technologies that reduce or eliminate fugitive emissions, and minimize environmental impacts resulting from construction activities. Increase the efficiency of...

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Aerobiology and the global transport of desert dust  

E-Print Network (OSTI)

misconception that all microorganisms in dust clouds are killed by solar UV-radiation, lack of nutrients and desiccation during their multi-day journey. In fact, some genera of bacteria (e.g. Bacillus) and most fungi

Ahmad, Sajjad

122

Metal Dusting [Corrosion and Mechanics of Materials] - Nuclear...  

NLE Websites -- All DOE Office Websites (Extended Search)

Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Corrosion and Mechanics of Materials Metal Dusting Bookmark and Share R&D 100 AWARD The "Materials resistant...

123

Saharan Dust Aerosol Radiative Forcing Measured from Space  

Science Conference Proceedings (OSTI)

This study uses data collected from the Clouds and the Earth's Radiant Energy System (CERES) and the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments to determine Saharan dust broadband shortwave aerosol radiative forcing over ...

F. Li; A. M. Vogelmann; V. Ramanathan

2004-07-01T23:59:59.000Z

124

Morphological investigations of fibrogenic action of Estonian oil shale dust  

SciTech Connect

A review of morphological investigations carried out to clarify the pathogenicity of industrial dust produced in the mining and processing of Estonian oil shale is given. Histological examination of lungs of workers in the oil shale industry taken at necropsies showed that the inhalation of oil shale dust over a long period (more than 20 years) may cause the development of occupational pneumoconiotic changes in oil shale miners. The pneumoconiotic process develops slowly and is characterized by changes typical of the interstitial form of pneumoconiotic fibrosis in the lungs. Emphysematous changes and chronic bronchitis also occur. The average chemical content of oil shale as well as of samples of oil shale dust generated during mining and sorting procedures is given. The results of experiments in white rats are presented; these studies also indicate a mild fibrogenic action of Estonian oil shale dust.

Kung, V.A.

1979-06-01T23:59:59.000Z

125

Thermal Impact of Saharan Dust over Land. Part I: Simnulation  

Science Conference Proceedings (OSTI)

Simulations are carded out to verify a mesoscale model in order to perform sensitivity tests of satellite response to atmospheric dust content. The model chosen is the mesoscale model of Colorado State University with a modified radiation ...

Guy Cautenet; Michel Legrand; Sylvie Cautenet; Bernard Bonnel; Gérard Brogniez

1992-02-01T23:59:59.000Z

126

A Case Study of Mobilization and Transport of Saharan Dust  

Science Conference Proceedings (OSTI)

Numerical models of the atmosphere and aerosols are used to investigate mobilization and transport of Saharan dust over West Africa and the tropical Atlantic Ocean for 23–28 August 1974. We have found that mobilization during this period was ...

Douglas L. Westphal; Owen B. Toon; Toby N. Carlson

1988-08-01T23:59:59.000Z

127

Dust Accumulation Biases in PIRATA Shortwave Radiation Records  

Science Conference Proceedings (OSTI)

Long-term and direct measurements of surface shortwave radiation (SWR) have been recorded by the Prediction and Research Moored Array in the Tropical Atlantic (PIRATA) since 1997. Previous studies have shown that African dust, transported westward ...

Gregory R. Foltz; Amato T. Evan; H. Paul Freitag; Sonya Brown; Michael J. McPhaden

2013-07-01T23:59:59.000Z

128

Next Century Challenges: Mobile Networking for "Smart Dust"  

E-Print Network (OSTI)

Next Century Challenges: Mobile Networking for "Smart Dust" J. M. Kahn, R. H. Katz (ACM Fellow), K be small enough to remain suspended in air, buoyed by air currents, sensing and communicating for hours

Kahn, Joseph M.

129

An experimental study of deflagration to detonation transition supported by dust layers  

SciTech Connect

The roles which dust layers play in severe dust explosions were investigated in a 70-m-long and 30-cm-diameter horizontal Flame Acceleration Tube (FAT) with one end closed and the other end open to the atmosphere. A variety of dusts such as corn dust, cornstarch, Mira Gel starch, wheat dust, and wood flour were layered on the bottom half of the FAT. Flame and detonation propagation parameters were closely monitored at different locations along the FAT. The study demonstrated that the moisture content of the dust, the exposed area of the dust layers to the convective flow, and the physical characteristics of the dust are the factors that most determine the severity of layered dust explosions, indicating that prelayered dust combustion is dominated by the dust/air mixing process. While the dust explosion rate constant K{sub st} can be used to characterize dust explosibility in predispersed dust in constant volume enclosures, it does not appear to characterize the behavior of layered dust explosions. Qualitative measurements of the variation of dust concentration during a layered dust explosion were obtained. The measurements indicated that the dust concentration at the time of flame arrival is highly nonuniform. The maximum pressure rise (P{sub max} {minus} P{sub 0}) within the FAT during a layered dust explosion was found to vary linearly with the flame velocity V{sub f} when V{sub f} is subsonic. As V{sub f} reaches supersonic values the maximum pressure increase was found to vary with the V{sub f}{sup 2}, the square of the flame velocity. This result was found to be independent of dust type and concentration.

Li, Y.C.; Kauffman, C.W.; Sichel, M. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Aerospace Engineering] [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Aerospace Engineering

1995-02-01T23:59:59.000Z

130

A SPITZER SURVEY FOR DUST IN TYPE IIn SUPERNOVAE  

Science Conference Proceedings (OSTI)

Recent observations suggest that Type IIn supernovae (SNe IIn) may exhibit late-time (>100 days) infrared (IR) emission from warm dust more than other types of core-collapse SNe. Mid-IR observations, which span the peak of the thermal spectral energy distribution, provide useful constraints on the properties of the dust and, ultimately, the circumstellar environment, explosion mechanism, and progenitor system. Due to the low SN IIn rate (<10% of all core-collapse SNe), few IR observations exist for this subclass. The handful of isolated studies, however, show late-time IR emission from warm dust that, in some cases, extends for five or six years post-discovery. While previous Spitzer/IRAC surveys have searched for dust in SNe, none have targeted the Type IIn subclass. This paper presents results from a warm Spitzer/IRAC survey of the positions of all 68 known SNe IIn within a distance of 250 Mpc between 1999 and 2008 that have remained unobserved by Spitzer more than 100 days post-discovery. The detection of late-time emission from 10 targets ({approx}15%) nearly doubles the database of existing mid-IR observations of SNe IIn. Although optical spectra show evidence for new dust formation in some cases, the data show that in most cases the likely origin of the mid-IR emission is pre-existing dust, which is continuously heated by optical emission generated by ongoing circumstellar interaction between the forward shock and circumstellar medium. Furthermore, an emerging trend suggests that these SNe decline at {approx}1000-2000 days post-discovery once the forward shock overruns the dust shell. The mass-loss rates associated with these dust shells are consistent with luminous blue variable progenitors.

Fox, Ori D. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Chevalier, Roger A.; Skrutskie, Michael F. [Department of Astronomy, University of Virginia, Charlottesville, VA 22903 (United States); Soderberg, Alicia M. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Filippenko, Alexei V.; Ganeshalingam, Mohan; Silverman, Jeffrey M.; Smith, Nathan; Steele, Thea N., E-mail: ori.d.fox@nasa.gov [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)

2011-11-01T23:59:59.000Z

131

Photochemical Oxidant Processes in the Presence of Dust: An Evaluation of the Impact of Dust on Particulate Nitrate and Ozone Formation  

Science Conference Proceedings (OSTI)

The influence of dust on the tropospheric photochemical oxidant cycle is studied through the use of a detailed coupled aerosol and gas-phase chemistry model. Dust is a significant component of the troposphere throughout Asia and provides a ...

Yang Zhang; Young Sunwoo; Veerabhadra Kotamarthi; Gregory R. Carmichael

1994-07-01T23:59:59.000Z

132

Dust explosion hazards due to blasting of oil shale  

SciTech Connect

The conditions favoring secondary explosions of dust or gas accompanying the blasting of oil shale are the subject of continuing investigation by the Bureau of Mines. In the present study, oil shale dust was dispersed in a gallery and ignited by various blasting agents blown out of a cannon according to a standard testing procedure. Parallel tests were conducted in the Bureau's Experimental Mine to test propagation as well as ignition of oil shale dust. In both gallery and mine, the minimum explosion limits were determined as a function of dust loading, weight and type of blasting agent, and amount of added methane. The results of these experiments are compared with previous measurements using methane-air explosions as an initiation source. In view of recent mine dust sampling data, the main explosion hazard in nongassy oil shale mines is likely to be limited to the region of the face. But in gassy mines, dust-gas explosions could be expected to propagate considerable distances.

Richmond, J.K.; Beitel, F.P.

1984-04-01T23:59:59.000Z

133

Bipolar charging of dust particles under ultraviolet radiation  

SciTech Connect

The photoemission charging of dust particles under ultraviolet radiation from a xenon lamp has been investigated. The velocities of yttrium dust particles with a work function of 3.3 eV and their charges have been determined experimentally; the latter are about 400-500 and about 100 elementary charges per micron of radius for the positively and negatively charged fractions, respectively. The dust particle charging and the dust cloud evolution in a photoemission cell after exposure to an ultraviolet radiation source under the applied voltage have been simulated numerically. The photoemission charging of dust particles has been calculated on the basis of nonlocal and local charging models. Only unipolar particle charging is shown to take place in a system of polydisperse dust particles with the same photoemission efficiency. It has been established that bipolar charging is possible in the case of monodisperse particles with different quantum efficiencies. Polydispersity in this case facilitates the appearance of oppositely charged particles in a photoemission plasma.

Filippov, A. V., E-mail: fav@triniti.ru; Babichev, V. N. [Troitsk Institute for Innovation and Fusion Research, State Research Center of the Russian Federation (Russian Federation); Fortov, V. E.; Gavrikov, A. V. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Pal', A. F. [Troitsk Institute for Innovation and Fusion Research, State Research Center of the Russian Federation (Russian Federation); Petrov, O. F. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Starostin, A. N.; Sarkarov, N. E. [Troitsk Institute for Innovation and Fusion Research, State Research Center of the Russian Federation (Russian Federation)

2011-05-15T23:59:59.000Z

134

Secular Instability and Planetesimal Formation in the Dust Layer  

E-Print Network (OSTI)

Late in the gaseous phase of a protostellar disk, centimeter-sized bodies probably settle into a thin ``dust layer'' at the midplane. A velocity difference between the dust layer and the gas gives rise to turbulence, which prevents further settling and direct gravitational instability of the layer. The associated drag on the surface of the layer causes orbital decay in a few thousand years---as opposed to a few hundred years for an isolated meter-sized body. Within this widely-accepted theoretical framework, we show that the turbulent drag causes radial instabilities even if the selfgravity of the layer is negligible. We formulate axisymmetric, height-integrated dynamical equations for the layer that incorporate turbulent diffusion of mass and momentum in radius and height, vertical settling, selfgravity, and resistance to compression due to gas entrained within the dust layer. In steady-state, the equations describe the inward radial drift of a uniform dust layer. In perturbation, overdense rings form on an orbital timescale with widths comparable to the dust-layer thickness. Selfgravity is almost irrelevant to the linear growth rate but will eventually fragment and collapse the rings into planetesimals larger than a kilometer. We estimate that the drag instability is most efficient at 1 AU when most of the ``dust'' mass lies in the size range 0.1-10 meters.

J. Goodman; B. Pindor

1999-12-28T23:59:59.000Z

135

HTGR Dust Safety Issues and Needs for Research and Development  

Science Conference Proceedings (OSTI)

This report presents a summary of high temperature gas-cooled reactor dust safety issues. It draws upon a literature review and the proceedings of the Very High Temperature Reactor Dust Assessment Meeting held in Rockville, MD in March 2011 to identify and prioritize the phenomena and issues that characterize the effect of carbonaceous dust on high temperature reactor safety. It reflects the work and input of approximately 40 participants from the U.S. Department of Energy and its National Labs, the U.S. Nuclear Regulatory Commission, industry, academia, and international nuclear research organizations on the topics of dust generation and characterization, transport, fission product interactions, and chemical reactions. The meeting was organized by the Idaho National Laboratory under the auspices of the Next Generation Nuclear Plant Project, with support from the U.S. Nuclear Regulatory Commission. Information gleaned from the report and related meetings will be used to enhance the fuel, graphite, and methods technical program plans that guide research and development under the Next Generation Nuclear Plant Project. Based on meeting discussions and presentations, major research and development needs include: generating adsorption isotherms for fission products that display an affinity for dust, investigating the formation and properties of carbonaceous crust on the inside of high temperature reactor coolant pipes, and confirming the predominant source of dust as abrasion between fuel spheres and the fuel handling system.

Paul W. Humrickhouse

2011-06-01T23:59:59.000Z

136

Energy conditions, traversable wormholes and dust shells  

E-Print Network (OSTI)

Firstly, we review the pointwise and averaged energy conditions, the quantum inequality and the notion of the ``volume integral quantifier'', which provides a measure of the ``total amount'' of energy condition violating matter. Secondly, we present a specific metric of a spherically symmetric traversable wormhole in the presence of a generic cosmological constant, verifying that the null and the averaged null energy conditions are violated, as was to be expected. Thirdly, a pressureless dust shell is constructed around the interior wormhole spacetime by matching the latter geometry to a unique vacuum exterior solution. In order to further minimize the usage of exotic matter, we then find regions where the surface energy density is positive, thereby satisfying all of the energy conditions at the junction surface. An equation governing the behavior of the radial pressure across the junction surface is also deduced. Lastly, taking advantage of the construction, specific dimensions of the wormhole, namely, the throat radius and the junction interface radius, and estimates of the total traversal time and maximum velocity of an observer journeying through the wormhole, are also found by imposing the traversability conditions.

Francisco S. N. Lobo

2004-10-18T23:59:59.000Z

137

Development of materials resistant to metal dusting degradation.  

DOE Green Energy (OSTI)

The deposition of carbon from carbonaceous gaseous environments is prevalent in many chemical and petrochemical processes such as, hydrogen-, ammonia-, and methanol-reforming systems, syngas production systems, and iron-ore reduction plants. One of the major consequences of carbon deposition is the degradation of structural materials by a phenomenon known as ''metal dusting''. There are two major issues of importance in metal dusting. First is formation of coke and subsequent deposition of coke on metallic structural components. Second is the initiation and subsequent propagation of metal dusting degradation of the structural alloy. In the past, we reported on the mechanism for metal dusting of Fe- and Ni-base alloys. In this report, we present metal dusting data on both Fe- and Ni-base alloys after exposure in high and atmospheric pressure environments that simulate the gas chemistry in operating hydrogen reformers. We have also measured the progression of pits by measuring the depth as a function of exposure time for a variety of Fe- and Ni-base structural alloys. We have clearly established the role of transport of iron in forming a non-protective spinel phase in the initiation process and presence of carbon transfer channels in the oxide scale for the continued propagation of pits, by nano-beam X-ray analysis using the advance photon source (APS), Raman scattering, and SEM/EDX analysis. In this report, we have developed correlations between weight loss and pit progression rates and evaluated the effects of carbon activity, system pressure, and alloy chemistry, on weight loss and pit propagation. To develop pit propagation data for the alloys without incurring substantial time for the initiation of pits, especially for the Ni-base alloys that exhibit incubation times of thousands of hours, a pre-pitting method has been developed. The pre-pitted alloys exhibited pit propagation rates similar to those of materials tested without pre-pitting. We have also developed a substantial body of metal-dusting data on the performance of Fe- and Ni-base weldments. During the course of this project, we have developed new Ni-base and Cu-base alloys and tested them in simulated metal dusting environments at 1 atm and at high pressures. Results clearly showed superior performance of both classes of alloys in resisting metal dusting. We also developed an approach to mitigate metal dusting by performing an intermediate oxidation step for extending the life of alloys in which metal dusting has initiated and pits are in progression. Finally, we have analyzed several components that have failed in plants such as hydrogen plant, pilot plant reformer, and a gas boiler.

Natesan, K.; Zeng, Z.; Nuclear Engineering Division

2007-12-07T23:59:59.000Z

138

Global dust model intercomparison in AeroCom phase I  

Science Conference Proceedings (OSTI)

Abstract. This study presents the results of a broad intercomparison of a total of 15 global aerosol models within the AeroCom project. Each model is compared to observations related to desert dust aerosols, their direct radiative effect, and their impact on the biogeochemical cycle, i.e., aerosol optical depth (AOD) and dust deposition. Additional comparisons to Angstr¨om exponent (AE), coarse mode AOD and dust surface concentrations are included to extend the assessment of model performance and to identify common biases present in models. These data comprise a benchmark dataset that is proposed for model inspection and future dust model development. There are large differences among the global models that simulate the dust cycle and its impact on climate. In general, models simulate the climatology of vertically integrated parameters (AOD and AE) within a factor of two whereas the total deposition and surface concentration are reproduced within a factor of 10. In addition, smaller mean normalized bias and root mean square errors are obtained for the climatology of AOD and AE than for total deposition and surface concentration. Characteristics of the datasets used and their uncertainties may influence these differences. Large uncertainties still exist with respect to the deposition fluxes in the southern oceans. Further measurements and model studies are necessary to assess the general model performance to reproduce dust deposition in ocean regions sensible to iron contributions. Models overestimate the wet deposition in regions dominated by dry deposition. They generally simulate more realistic surface concentration at stations downwind of the main sources than at remote ones. Most models simulate the gradient in AOD and AE between the different dusty regions. However the seasonality and magnitude of both variables is better simulated at African stations than Middle East ones. The models simulate the offshore transport of West Africa throughout the year but they overestimate the AOD and they transport too fine particles. The models also reproduce the dust transport across the Atlantic in the summer in terms of both AOD and AE but not so well in winter-spring nor the southward displacement of the dust cloud that is responsible of the dust transport into South America. Based on the dependency of AOD on aerosol burden and size distribution we use model bias with respect to AOD and AE to infer the bias of the dust emissions in Africa and the Middle East. According to this analysis we suggest that a range of possible emissions for North Africa is 400 to 2200 Tg yr?1 and in the Middle East 26 to 526 Tg yr?1.

Huneeus, N.; Schulz, M.; Balkanski, Y.; Griesfeller, J.; Prospero, J.; Kinne, Stefan; Bauer, S.; Boucher, O.; Chin, M.; Dentener, F.; Diehl, T.; Easter, Richard C.; Fillmore, D.; Ghan, Steven J.; Ginnoux, P.; Grini, A.; Horowitz, L.; Koch, D.; Krol, M.; Landing, W.; Liu, Xiaohong; Mahowald, N.; Miller, R.; Morcrette, J. -J.; Myhre, G.; Penner, J.; Perlwitz, J.; Stier, P.; Takemura, T.; Zender, C. S.

2011-08-18T23:59:59.000Z

139

THE S{sup 4}G PERSPECTIVE ON CIRCUMSTELLAR DUST EXTINCTION OF ASYMPTOTIC GIANT BRANCH STARS IN M100  

SciTech Connect

We examine the effect of circumstellar dust extinction on the near-IR (NIR) contribution of asymptotic giant branch (AGB) stars in intermediate-age clusters throughout the disk of M100. For our sample of 17 AGB-dominated clusters we extract optical-to-mid-IR spectral energy distributions (SEDs) and find that NIR brightness is coupled to the mid-IR dust emission in such a way that a significant reduction of AGB light, of up to 1 mag in the K band, follows from extinction by the dust shell formed during this stage. Since the dust optical depth varies with AGB chemistry (C-rich or O-rich), our results suggest that the contribution of AGB stars to the flux from their host clusters will be closely linked to the metallicity and the progenitor mass of the AGB star, to which dust chemistry and mass-loss rate are sensitive. Our sample of clusters-each the analogue of a {approx}1 Gyr old post-starburst galaxy-has implications within the context of mass and age estimation via SED modeling at high-z: we find that the average {approx}0.5 mag extinction estimated here may be sufficient to reduce the AGB contribution in the (rest-frame) K band from {approx}70%, as predicted in the latest generation of synthesis models, to {approx}35%. Our technique for selecting AGB-dominated clusters in nearby galaxies promises to be effective for discriminating the uncertainties associated with AGB stars in intermediate-age populations that plague age and mass estimation in high-z galaxies.

Meidt, Sharon E.; Schinnerer, Eva [Max-Planck-Institut fuer Astronomie/Koenigstuhl 17, D-69117 Heidelberg (Germany); Munoz-Mateos, Juan-Carlos; Kim, Taehyun [National Radio Astronomy Observatory, Charlottesville, VA (United States); Holwerda, Benne [European Space Agency, ESTEC, Keplerlaan 1, 2200 AG, Noordwijk (Netherlands); Ho, Luis C.; Madore, Barry F.; Sheth, Kartik; Menendez-Delmestre, Karin; Seibert, Mark [The Observatories of the Carnegie Institution for Science, Pasadena, CA (United States); Knapen, Johan H. [Instituto de Astrofisica de Canarias, Tenerife (Spain); Bosma, Albert; Athanassoula, E. [Laboratoire d'Astrophysique de Marseille (LAM), Marseille (France); Hinz, Joannah L. [Department of Astronomy, University of Arizona, Tucson, AZ (United States); Regan, Michael [Space Telescope Science Institute, Baltimore, MD (United States); De Paz, Armando Gil [Departamento de Astrofisica, Universidad Complutense Madrid, Madrid (Spain); Mizusawa, Trisha [Spitzer Science Center, Pasadena, CA (United States); Gadotti, Dimitri A. [European Southern Observatory, Santiago (Chile); Laurikainen, Eija; Salo, Heikki [Astronomy Division, Department of Physical Sciences, University of Oulu, Oulu (Finland); and others

2012-04-01T23:59:59.000Z

140

Reducing waste, Photoby stcvcchan  

E-Print Network (OSTI)

I ' I I t Reducing waste, Photoby stcvcchan AMs President Mike Lee (left to right), Point Grey M U recycling given high priority on campus By GAVIN WILSON UBC is taking stepsto reduce waste and encourageGellatly,Vice-President,Administration and Finance,to develop and recommend university policies on waste recycling. Another task force has submitted

Farrell, Anthony P.

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

A Spitzer search for cold dust within globular clusters  

E-Print Network (OSTI)

Globular cluster stars evolving off the main sequence are known to lose mass, and it is expected that some of the lost material should remain within the cluster as an intracluster medium (ICM). Most attempts to detect such an ICM have been unsuccessful. The Multiband Imaging Photometer for Spitzer on the Spitzer Space Telescope was used to observe eight Galactic globular clusters in an attempt to detect the thermal emission from ICM dust. Most clusters do not have significant detections at 70 microns; one cluster, NGC 6341, has tentative evidence for the presence of dust, but 90 micron observations do not confirm the detection. Individual 70 micron point sources which appear in several of the cluster images are likely to be background galaxies. The inferred dust mass and upper limits are solar masses, well below expectations for cluster dust production from mass loss in red and asymptotic giant branch stars. This implies that either globular cluster dust production is less efficient, or that ICM rem...

Barmby, P; Woodward, C E; Gehrz, R D; van Loon, J Th; Fazio, G G; Marengo, M; Polomski, E

2008-01-01T23:59:59.000Z

142

Modeling the Dust Spectral Energy Distributions of Dwarf Galaxies  

E-Print Network (OSTI)

Recent efforts on the modeling of the infrared spectral energy distributions (SEDs) of dwarf galaxies are summarised here. The characterisation of the dust properties in these low metallicity environments is just unfolding, as a result of recently available mid-infrared to millimetre observations. From the limited cases we know to date, it appears that the hard radiation fields that are present in these star-bursting dwarf galaxies, as well as the rampent energetics of supernovae shocks and winds have modified the dust properties, in comparison with those in the Galaxy, or other gas and dust rich galaxies. The sophistication of the SED models is limited by the availability of detailed data in the mid infrared and particularly in the submillimetre to millimetre regime, which will open up in the near future with space-based missions, such as Herschel.

Suzanne C. Madden

2005-01-31T23:59:59.000Z

143

Infrared Emission from Interstellar Dust. III. The Small Magellanic Cloud  

E-Print Network (OSTI)

The infrared (IR) emission from interstellar dust in the Small Magellanic Cloud (SMC) is modelled using a mixture of amorphous silicate and carbonaceous grains, including a population of polycyclic aromatic hydrocarbon (PAH) molecules. (1) It is shown that this dust model is able to reproduce the spectral energy distribution from near-IR to far-IR for the entire SMC Bar region, provided the PAH abundance in the SMC Bar region is very low. (2) The IR spectrum of the SMCB1#1 molecular cloud can also be reproduced by our dust model provided the PAH abundance is increased relative to the overall SMC Bar. The PAHs in SMCB1#1 incorporate ~3% of the SMC C abundance, compared to environmental conditions. Other possibilities such as super-hydrogenation of PAHs and softening of the starlight spectrum are also discussed.

Aigen Li; B. T. Draine

2001-12-05T23:59:59.000Z

144

Lithium Wall Conditioning And Surface Dust Detection On NSTX  

Science Conference Proceedings (OSTI)

Lithium evaporation onto NSTX plasma facing components (PFC) has resulted in improved energy confinement, and reductions in the number and amplitude of edge-localized modes (ELMs) up to the point of complete ELM suppression. The associated PFC surface chemistry has been investigated with a novel plasma material interface probe connected to an in-vacuo surface analysis station. Analysis has demonstrated that binding of D atoms to the polycrystalline graphite material of the PFCs is fundamentally changed by lithium - in particular deuterium atoms become weakly bonded near lithium atoms themselves bound to either oxygen or the carbon from the underlying material. Surface dust inside NSTX has been detected in real-time using a highly sensitive electrostatic dust detector. In a separate experiment, electrostatic removal of dust via three concentric spiral-shaped electrodes covered by a dielectric and driven by a high voltage 3-phase waveform was evaluated for potential application to fusion reactors

Skinner, C H; Bell, M G; Friesen, F.Q.L.; Heim, B; Jaworski, M A; Kugel, H; Maingi, R; Rais, B

2011-05-23T23:59:59.000Z

145

Reduce Oil Dependence Costs  

NLE Websites -- All DOE Office Websites (Extended Search)

Reduce Oil Dependence Costs U.S. Petroleum Use, 1970-2010 Nearly 40% of the oil we use is imported, costing us roughly 300 billion annually. Increased domestic oil production from...

146

Reducing Diesel Engine Emissions  

NLE Websites -- All DOE Office Websites (Extended Search)

Reducing Reducing Diesel Engine Emissions 2 0 1 0 Green TransporTaTion TechnoloGies Compared to traditional gasoline engines, diesel engines require less maintenance, generate energy more efficiently, and produce less carbon dioxide emissions. But when uncontrolled, diesel engines churn out harmful emissions like particu- late matter (PM) and nitrogen oxides (NO x ). Researchers at Argonne National Laboratory are currently working to develop

147

Dust Tracking Using Composite Visible/IR Images: A Case Study  

Science Conference Proceedings (OSTI)

Visible and infrared (IR) images from the National Oceanic and Atmospheric Administration's (NOAA's) Advanced Very High Resolution Radiometer are composited to improve the depiction of airborne dust over coastlines. On IR images, wind-raised dust ...

Thomas F. Lee

1989-06-01T23:59:59.000Z

148

Radiative Effects of Airborne Dust on Regional Energy Budgets at the Top of the Atmosphere  

Science Conference Proceedings (OSTI)

The effects of dust on the radiative energy budget at the top of the atmosphere were investigated using model calculations and measurements from the Earth Radiation Budget Experiment (ERBE). Estimates of the dust optical depth were made from ...

Steven A. Ackerman; Hyosang Chung

1992-02-01T23:59:59.000Z

149

Multidecadal Covariability of North Atlantic Sea Surface Temperature, African Dust, Sahel Rainfall, and Atlantic Hurricanes  

Science Conference Proceedings (OSTI)

Most studies of African dust and North Atlantic climate have been limited to the short time period since the satellite era (1980 onward), precluding the examination of their relationship on longer time scales. Here a new dust dataset with the ...

Chunzai Wang; Shenfu Dong; Amato T. Evan; Gregory R. Foltz; Sang-Ki Lee

2012-08-01T23:59:59.000Z

150

Integrated impact analysis of yellow-dust storms : a regional case study in China  

E-Print Network (OSTI)

The dust storm is a meteorological event that is caused by strong winds and proceeds from arid and semi-arid regions, transporting a thick cloud of fine sediments. In China, the sediments of dust storms mainly come from ...

Ai, Ning, 1978-

2003-01-01T23:59:59.000Z

151

Existence domains of large amplitude dust-acoustic solitons in non-thermal plasmas with positive and negative dust  

Science Conference Proceedings (OSTI)

Using the traditional Sagdeev pseudopotential approach, the existence of large amplitude solitons is investigated for a plasma composed of cold negative dust, adiabatic positive dust, non-thermal ions and Boltzmann electrons. The lower and upper soliton Mach number limitations are determined as a function of various parameters and physical reasons are provided as to why these Mach number limits occur. Some regions in parameter space have been identified where only negative or positive solitons occur, whereas, other regions support the coexistence of both positive and negative potential solitons.

Maharaj, S. K. [South African National Space Agency Space Science, P O Box 32, Hermanus 7200 (South Africa); Bharuthram, R. [University of the Western Cape, Modderdam Road, Bellville 7530 (South Africa); Singh, S. V.; Lakhina, G. S. [Indian Institute of Geomagnetism, New Panvel, Navi Mumbai 410218 (India); Pillay, S. R. [University of KwaZulu-Natal, Private Bag X54001, Durban 4000 (South Africa)

2011-11-29T23:59:59.000Z

152

Large amplitude dust-acoustic double layers in non-thermal plasmas with positive and negative dust  

Science Conference Proceedings (OSTI)

The existence of large amplitude double layers in a plasma composed of cold negative dust, adiabatic positive dust, non-thermal ions and Boltzmann electrons is investigated using the Sagdeev pseudopotential technique. Both positive potential and negative potential double layers are found to be supported by the model. The variation of the maximum amplitudes of the double layers and corresponding Mach numbers are examined as a function of various plasma parameters. In particular, we investigate to what extent ion non-thermal effects are required for positive potential double layers to occur.

Maharaj, S. K. [South African National Space Agency Space Science, P O Box 32, Hermanus 7200 (South Africa); Bharuthram, R. [University of the Western Cape, Modderdam Road, Bellville 7530 (South Africa); Singh, S. V.; Lakhina, G. S. [Indian Institute of Geomagnetism, New Panvel, Navi Mumbai 410218 (India); Pillay, S. R. [University of KwaZulu-Natal, Private Bag X54001, Durban 4000 (South Africa)

2011-11-29T23:59:59.000Z

153

Kinetic theory of magnetized dusty plasmas with dust particles charged by collisional processes and by photoionization  

SciTech Connect

In this work, we detail the derivation of a plasma kinetic theory leading to the components of the dielectric tensor for a magnetized dusty plasma with variable charge on the dust particles, considering that the dust component of the plasma contains spherical dust particles with different sizes, which are charged both by inelastic collisions of electrons and ions and by photoionization.

Galvao, R. A.; Ziebell, L. F. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS (Brazil)

2012-09-15T23:59:59.000Z

154

COAMPS Real-Time Dust Storm Forecasting during Operation Iraqi Freedom  

Science Conference Proceedings (OSTI)

Dust storms are a significant weather phenomenon in the Iraq region in winter and spring. Real-time dust forecasting using the U.S. Navy’s Coupled Ocean–Atmospheric Mesoscale Prediction System (COAMPS) with an in-line dust aerosol model was ...

Ming Liu; Douglas L. Westphal; Annette L. Walker; Teddy R. Holt; Kim A. Richardson; Steven D. Miller

2007-02-01T23:59:59.000Z

155

Optical Investigations of Dust Particles Distribution in RF and DC Discharges  

Science Conference Proceedings (OSTI)

Optical emission spectroscopy is used to study dust particles movement and conditions of a formation of ordered plasma-dust structures in a capacitively coupled RF discharge. 3D binocular diagnostics of plasma-dust structures in dc discharge was made.

Ramazanov, T. S.; Dosbolayev, M. K.; Jumabekov, A. N.; Amangaliyeva, R. Zh. [Al-Farabi Kazakh National University, IETP, 96a Tole Bi St., Almaty 050012 (Kazakhstan); Filatova, I. I.; Azharonok, V. V. [B. I. Stepanov Institute of Physics NAS of Belarus, Nezavisimosti Ave., 68, 220072, Minsk (Belarus)

2008-09-07T23:59:59.000Z

156

The Diurnal and Seasonal Cycles of Wind-Borne Dust over Africa North of the Equator  

Science Conference Proceedings (OSTI)

This article presents a study of the diurnal and seasonal cycles of dust over North Africa, using surface visibility as an indicator of dust. The diurnal cycle shows a reduction of visibility during the daytime hours in the areas where dust is ...

G. N’Tchayi Mbourou; J. J. Bertrand; S. E. Nicholson

1997-07-01T23:59:59.000Z

157

Railroads and shippers clash over coal dust  

Science Conference Proceedings (OSTI)

In an effort to reduce coal spillage from railcars, mines in the Powder River Basin (PRB) now load coal with a loaf profile but, reportedly, beginning in 2008, Burlington Northern Santa Fe (BNSF) will announce guidelines requiring all PRB coal loads to be sprayed with a chemical surfactant. If this does not fix the problem, greater measures will be taken. At the time of going to press, the details of how this would be implemented and regulated were unresolved. 1 photo.

Buchsbaum, L.

2007-11-15T23:59:59.000Z

158

SPATIAL VARIATIONS OF DUST ABUNDANCES ACROSS THE LARGE MAGELLANIC CLOUD  

SciTech Connect

Using the data obtained with the Spitzer Space Telescope as part of the Surveying the Agents of a Galaxy's Evolution (SAGE) legacy survey, we have studied the variations of the dust composition and abundance across the Large Magellanic Cloud (LMC). Such variations are expected, as the explosive events which have lead to the formation of the many H I shells observed should have affected the dust properties. Using a model and comparing with a reference spectral energy distribution from our Galaxy, we deduce the relative abundance variations of small dust grains across the LMC. We examined the infrared color ratios as well as the relative abundances of very small grains (VSGs) and polycyclic aromatic hydrocarbons (PAHs) relative to the big grain abundance. Results show that each dust component could have different origins or evolution in the interstellar medium (ISM). The VSG abundance traces the star formation activity and could result from shattering of larger grains, whereas the PAH abundance increases around molecular clouds as well as in the stellar bar, where they could have been injected into the ISM during mass loss from old stars.

Paradis, Deborah; Reach, William T. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Bernard, Jean-Philippe [Universite de Toulouse, UPS, CESR, 9 av. du Colonel Roche, F-31028 Toulouse cedex 9 (France); Block, Miwa; Engelbracht, Chad W.; Gordon, Karl [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Hora, Joseph L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., MS-65, Cambridge, MA, 02138-1516 (United States); Indebetouw, Remy [7 National Radio Astronomy Observatory and Department of Astronomy, University of Virginia, P.O. Box 3818, Charlottesville, VA 22903-0818 (United States); Kawamura, Akiko [Nagoya University, Department of Astrophysics, Chikusa-Ku, Nagoya, 464-01 (Japan); Meade, Marilyn [Department of Astronomy, University of Wisconsin, Madison, 475 N. Charter St., Madison, WI 53706 (United States); Meixner, Margaret; Sewilo, Marta [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Vijh, Uma P. [Ritter Astrophysical Research Center, University of Toledo, Toledo, OH 43606 (United States); Volk, Kevin [Gemini Observatory, Northern Operations Center, 670 N. Aohuku Place, Hilo, HI 96720 (United States)

2009-07-15T23:59:59.000Z

159

Dust and the ultraviolet energy distribution of quasars  

E-Print Network (OSTI)

The ultraviolet energy distribution of quasars shows a sharp steepening of the continuum shortward of 1000 A (rest-frame). We describe how we came to consider the possibility that this continuum break might be the result of absorption by carbon crystallite dust grains.

Luc Binette; Christophe Morisset; Sinhue Haro-Corzo

2005-09-24T23:59:59.000Z

160

Gas-cooling by dust during dynamical fragmentation  

E-Print Network (OSTI)

We suggest that the abrupt switch, from hierarchical clustering on scales larger than 0.04 pc, to binary (and occasionally higher multiple) systems on smaller scales, which Larson has deduced from his analysis of the grouping of pre-Main-Sequence stars in Taurus, arises because pre-protostellar gas becomes thermally coupled to dust at sufficiently high densities. The resulting change from gas-cooling by molecular lines at low densities to gas-cooling by dust at high densities enables the matter to radiate much more efficiently, and hence to undergo dynamical fragmentation. We derive the domain where gas-cooling by dust facilitates dynamical fragmentation. Low-mass (i.e. solar mass) clumps - those supported mainly by thermal pressure - can probably access this domain spontaneously, albeit rather quasistatically, provided they exist in a region where external perturbations are few and far between. More massive clumps probably require an impulsive external perturbation, for instance a supersonic collision with another clump, in order for the gas to reach sufficiently high density to couple thermally to the dust. Impulsive external perturbations should promote fragmentation, by generating highly non-line ar substructures which can then be amplified by gravity during the subsequent collapse.

A. P. Whitworth; H. M. J. Boffin; N. Francis

1998-04-30T23:59:59.000Z

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Simulation of Transport and Removal Processes of the Saharan Dust  

Science Conference Proceedings (OSTI)

A planetary boundary layer (PBL) model has been modified to include a Saharan air layer containing the bulk of Saharan dust. The Saharan air layer is recognized as a deep mixed layer which extends up to 4–6 km during hot summer months and is ...

In-Young Lee

1983-04-01T23:59:59.000Z

162

Stochastic fluctuations of dust particle charge in RF discharges  

Science Conference Proceedings (OSTI)

In addition to RF oscillations, intrinsic stochastic fluctuations due to the discreteness of electrons and ions could be important to the charging of a dust particle in RF discharges. These fluctuations are studied in the present work for three cases [M. Bacharis et al., Plasma Sources Sci. Technol. 19, 025002 (2010)] relevant to RF discharges employing a recently proposed model [B. Shotorban, Phys. Rev. E 83, 066403 (2011)] valid for stochastic charging at nonstationary states. The cases are concerned with a time varying electron number density relevant to sheaths, a time varying electric field relevant to the bulk plasma, and a time-dependent bi-Maxwellian distribution of electrons in a low pressure discharge. Two dust particles with different sizes are individually studied in each case. The radius of one is ten times larger than the radius of the other. In all of the cases, for the larger dust particle, the root-mean-squre of charge stochastic fluctuations is about an order of magnitude smaller than the amplitude of RF charge oscillations, while for the smaller dust particle, they are comparable in magnitude.

Shotorban, B. [Department of Mechanical and Aerospace Engineering, University of Alabama in Huntsville, Huntsville, Alabama 35899 (United States)

2012-05-15T23:59:59.000Z

163

Global observations of desert dust and biomass burning aerosols  

E-Print Network (OSTI)

Global observations of desert dust and biomass burning aerosols Martin de Graaf KNMI #12; Outline · Absorbing Aerosol Index - Theory · Absorbing Aerosol Index - Reality · Biomass burning.6 Biomass burning over Angola, 09 Sep. 2004 Absorbing Aerosol Index PMD image #12;biomass burning ocean

Graaf, Martin de

164

Doppler Radar Observations of Dust Devils in Texas  

Science Conference Proceedings (OSTI)

Analyses of a dust-devil dataset collected in northwest Texas are presented. The data were collected just above the ground at close range with a mobile, W-band (3-mm wavelength) Doppler radar having an azimuthal (radial) resolution of 3–5 m (30 m)...

Howard B. Bluestein; Christopher C. Weiss; Andrew L. Pazmany

2004-01-01T23:59:59.000Z

165

Reduced power consumption in  

E-Print Network (OSTI)

and a potential energy savings of over $30 Billion/year. This new approach is demanded by the exponentiallyBenefits Reduced power consumption in IC devices; hence potential energy savings of 300 Billion KWh://www.sia- online.org) CuRIE Interconnect Technology for Improved Energy Efficiency in IC Chips ARPA-E Technology

166

Reduces electric energy consumption  

E-Print Network (OSTI)

implementation of the assessment recommendations is estimated to be $843,000 with a total implementation cost. Manufacturing at the facility includes both casting and extrusion processes. Process equipment, air compressors productivity. As a result, facility production costs can be reduced and profits can be increased. August 2001

167

Airborne Sunphotometry and Integrated Analyses of Dust, Other Aerosols, and Water Vapor in the Puerto Rico Dust Experiment (PRIDE)  

E-Print Network (OSTI)

in the Puerto Rico Dust Experiment (PRIDE) PI: Philip B. Russell MS 245-5, NASA Ames Research Center Moffett new analyses of aerosol radiative forcing sensitivity, single scattering albedo, and the solar spectral radiative energy budget. (h) Derive aerosol size distributions from optical depth and extinction

168

Molecular Determinants for Antibody Binding on Group 1 House Dust Mite Allergens  

SciTech Connect

House dust mites produce potent allergens, Der p 1 and Der f 1, that cause allergic sensitization and asthma. Der p 1 and Der f 1 are cysteine proteases that elicit IgE responses in 80% of mite-allergic subjects and have proinflammatory properties. Their antigenic structure is unknown. Here, we present crystal structures of natural Der p 1 and Der f 1 in complex with a monoclonal antibody, 4C1, which binds to a unique cross-reactive epitope on both allergens associated with IgE recognition. The 4C1 epitope is formed by almost identical amino acid sequences and contact residues. Mutations of the contact residues abrogate mAb 4C1 binding and reduce IgE antibody binding. These surface-exposed residues are molecular targets that can be exploited for development of recombinant allergen vaccines.

Chruszcz, Maksymilian; Pomés, Anna; Glesner, Jill; Vailes, Lisa D.; Osinski, Tomasz; Porebski, Przemyslaw J.; Majorek, Karolina A.; Heymann, Peter W.; Platts-Mills, Thomas A.E.; Minor, Wladek; Chapman, Martin D. (INDOOR Bio.); (UV); (UVHS)

2012-07-11T23:59:59.000Z

169

Reduce Climate Change  

NLE Websites -- All DOE Office Websites (Extended Search)

Reduce Climate Change Reduce Climate Change Highway vehicles release about 1.5 billion metric tons of greenhouse gases (GHGs) into the atmosphere each year-mostly in the form of carbon dioxide (CO2)-contributing to global climate change. Each gallon of gasoline you burn creates 20 pounds of CO2. That's roughly 5 to 9 tons of CO2 each year for a typical vehicle. more... How can a gallon of gasoline create 20 pounds of carbon dioxide? It seems impossible that a gallon of gasoline, which weighs about 6.3 pounds, could produce 20 pounds of carbon dioxide (CO2) when burned. However, most of the weight of the CO2 doesn't come from the gasoline itself, but the oxygen in the air. When gasoline burns, the carbon and hydrogen separate. The hydrogen combines with oxygen to form water (H2O), and carbon combines with oxygen

170

Naval electrochemical corrosion reducer  

DOE Patents (OSTI)

A corrosion reducer for use with ships having a hull, a propeller mounted a propeller shaft and extending through the hull, bearings supporting the shaft, at least one thrust bearing and one seal. The improvement includes a current collector and a current reduction assembly for reducing the voltage between the hull and shaft in order to reduce corrosion due to electrolytic action. The current reduction assembly includes an electrical contact, the current collector, and the hull. The current reduction assembly further includes a device for sensing and measuring the voltage between the hull and the shaft and a device for applying a reverse voltage between the hull and the shaft so that the resulting voltage differential is from 0 to 0.05 volts. The current reduction assembly further includes a differential amplifier having a voltage differential between the hull and the shaft. The current reduction assembly further includes an amplifier and a power output circuit receiving signals from the differential amplifier and being supplied by at least one current supply. The current selector includes a brush assembly in contact with a slip ring over the shaft so that its potential may be applied to the differential amplifier.

Clark, Howard L. (Ballston Lake, NY)

1991-10-01T23:59:59.000Z

171

Method and apparatus for measuring surface density of explosive and inert dust in stratified layers  

SciTech Connect

A method for determining the surface density of coal dust on top of rock dust or rock dust on top of coal dust is disclosed which comprises directing a light source at either a coal or rock dust layer overlaying a substratum of the other, detecting the amount of light reflected from the deposit, generating a signal from the reflected light which is converted into a normalized output (V), and calculating the surface density from the normalized output. The surface density S.sub.c of coal dust on top of rock dust is calculated according to the equation: S.sub.c =1/-a.sub.c ln(V) wherein a.sub.c is a constant for the coal dust particles, and the surface density S.sub.r of rock dust on top of coal dust is determined by the equation: ##EQU1## wherein a.sub.r is a constant based on the properties of the rock dust particles. An apparatus is also disclosed for carrying out the method of the present invention.

Sapko, Michael J. (Finleyville, PA); Perlee, Henry E. (Bethel Park, PA)

1988-01-01T23:59:59.000Z

172

Dust Deserves More than the Brush-Off | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Dust Deserves More than the Brush-Off Dust Deserves More than the Brush-Off Dust Deserves More than the Brush-Off July 6, 2012 - 10:35am Addthis The dust particles act as a "heat pump" drawing heat from the sun and surface, and attracting moisture from the Gulf of California and the Gulf of Mexico. Without dust, rainfall would be up to 40 percent less over Arizona, New Mexico and Texas. | Creative Commons photo by Jared The dust particles act as a "heat pump" drawing heat from the sun and surface, and attracting moisture from the Gulf of California and the Gulf of Mexico. Without dust, rainfall would be up to 40 percent less over Arizona, New Mexico and Texas. | Creative Commons photo by Jared

173

Dust-acoustic shock formation in adiabatic hot dusty plasmas with variable charge  

Science Conference Proceedings (OSTI)

Shocklike structure can be formed after a certain transient time due to the self-steepening of the negative potential. In order to have a monotonic or oscillatory shock wave, it is known that a source of dissipation is needed. In this study, we considered the variation of dust charge as a source of dissipation. By using the reductive perturbation technique, the nonlinear Burgers equation is derived and the shocklike solution is determined. The effects of dust temperature on different characteristics of dust-acoustic shock structure are discussed. It is found out that the dust thickness is not affected by dust temperature. By considering a dusty plasma system with a set of parameters, it is shown that there exists a specific dust critical temperature T{sub dc} which gives maximum height for the dust-acoustic shock structure. The effects of the plasma species temperature on shock formation are also investigated.

Asgari, H.; Muniandy, S. V.; Wong, C. S. [Department of Physics, Plasma Research Laboratory, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2011-01-15T23:59:59.000Z

174

Effect of energetic electrons on dust charging in hot cathode filament discharge  

Science Conference Proceedings (OSTI)

The effect of energetic electrons on dust charging for different types of dust is studied in hydrogen plasma. The hydrogen plasma is produced by hot cathode filament discharge method in a dusty plasma device. A full line cusped magnetic field cage is used to confine the plasma elements. To study the plasma parameters for various discharge conditions, a cylindrical Langmuir probe having 0.15 mm diameter and 10.0 mm length is used. An electronically controlled dust dropper is used to drop the dust particles into the plasma. For different discharge conditions, the dust current is measured using a Faraday cup connected to an electrometer. The effect of secondary emission as well as discharge voltage on charging of dust grains in hydrogen plasma is studied with different dust.

Kakati, B.; Kausik, S. S.; Saikia, B. K. [Centre of Plasma Physics, Institute for Plasma Research, Nazirakhat, Sonapur 782 402, Kamrup, Assam (India); Bandyopadhyay, M. [ITER-India, Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India)

2011-03-15T23:59:59.000Z

175

Carbon formation and metal dusting in advanced coal gasification processes  

SciTech Connect

The product gases generated by coal gasification systems contain high concentrations of CO and, characteristically, have relatively high carbon activities. Accordingly, carbon deposition and metal dusting can potentially degrade the operation of such gasifier systems. Therefore, the product gas compositions of eight representative gasifier systems were examined with respect to the carbon activity of the gases at temperatures ranging from 480 to 1,090 C. Phase stability calculations indicated that Fe{sub 3}C is stable only under very limited thermodynamic conditions and with certain kinetic assumptions and that FeO and Fe{sub 0.877}S tend to form instead of the carbide. As formation of Fe{sub 3}C is a necessary step in the metal dusting of steels, there are numerous gasifier environments where this type of carbon-related degradation will not occur, particularly under conditions associated with higher oxygen and sulfur activities. These calculations also indicated that the removal of H{sub 2}S by a hot-gas cleanup system may have less effect on the formation of Fe{sub 3}C in air-blown gasifier environments, where the iron oxide phase can exist and is unaffected by the removal of sulfur, than in oxygen-blown systems, where iron sulfide provides the only potential barrier to Fe{sub 3}C formation. Use of carbon- and/or low-alloy steels dictates that the process gas composition be such that Fe{sub 3}C cannot form if the potential for metal dusting is to be eliminated. Alternatively, process modifications could include the reintroduction of hydrogen sulfide, cooling the gas to perhaps as low as 400 C and/or steam injection. If higher-alloy steels are used, a hydrogen sulfide-free gas may be processed without concern about carbon deposition and metal dusting.

DeVan, J.H.; Tortorelli, P.F.; Judkins, R.R.; Wright, I.G.

1997-02-01T23:59:59.000Z

176

Canadian House Dust Study: Lead Bioaccessibility and Speciation  

Science Conference Proceedings (OSTI)

Vacuum samples were collected from 1025 randomly selected urban Canadian homes to investigate bioaccessible Pb (Pb{sub S}) concentrations in settled house dust. Results indicate a polymodal frequency distribution, consisting of three lognormally distributed subpopulations defined as 'urban background' (geomean 58 {micro}g g{sup -1}), 'elevated' (geomean 447 {micro}g g{sup -1}), and 'anomalous' (geomean 1730 {micro}g g{sup -1}). Dust Pb{sub S} concentrations in 924 homes (90%) fall into the 'urban background' category. The elevated and anomalous subpopulations predominantly consist of older homes located in central core areas of cities. The influence of house age is evidenced by a moderate correlation between house age and dust Pb{sub S} content (R{sup 2} = 0.34; n = 1025; p < 0.01), but it is notable that more than 10% of homes in the elevated/anomalous category were built after 1980. Conversely, the benefit of home remediation is evidenced by the large number of homes (33%) in the background category that were built before 1960. The dominant dust Pb species determined using X-ray Absorption Spectroscopy were as follows: Pb carbonate, Pb hydroxyl carbonate, Pb sulfate, Pb chromate, Pb oxide, Pb citrate, Pb metal, Pb adsorbed to Fe- and Al-oxyhydroxides, and Pb adsorbed to humate. Pb bioaccessibility estimated from solid phase speciation predicts Pb bioaccessibility measured using a simulated gastric extraction (R{sup 2} = 0.85; n = 12; p < 0.0001). The trend toward increased Pb bioaccessibility in the elevated and anomalous subpopulations (75% {+-} 18% and 81% {+-} 8%, respectively) compared to background (63% {+-} 18%) is explained by the higher proportion of bioaccessible compounds used as pigments in older paints (Pb carbonate and Pb hydroxyl carbonate). This population-based study provides a nationally representative urban baseline for applications in human health risk assessment and risk management.

P Rasmussen; S Beauchemin; M Chenier; C Levesque; L MacLean; L Marrow; H Jones-Otazo; S Petrovic; L McDonald; H Gardner

2011-12-31T23:59:59.000Z

177

Dust Static Spherically Symmetric Solution in $f(R)$ Gravity  

E-Print Network (OSTI)

In this paper, we take dust matter and investigate static spherically symmetric solution of the field equations in metric f(R) gravity. The solution is found with constant Ricci scalar curvature and its energy distribution is evaluated by using Landau-Lifshitz energy-momentum complex. We also discuss the stability condition and constant scalar curvature condition for some specific popular choices of f(R) models in addition to their energy distribution.

Muhammad Sharif; Hafiza Rizwana Kausar

2011-02-21T23:59:59.000Z

178

Effect of Direct Radiative Forcing of Asian Dust on the Meteorological Fields in East Asia during an Asian Dust Event Period  

Science Conference Proceedings (OSTI)

Coupled and noncoupled models in a grid of 60 × 60 km2 in the eastern Asian domain have been employed to examine the effect of the direct radiative forcing of the Asian dust aerosol on meteorological fields for an intense Asian dust event ...

Hyun-Ju Ahn; Soon-Ung Park; Lim-Seok Chang

2007-10-01T23:59:59.000Z

179

Effects of polarization force and effective dust temperature on dust-acoustic solitary and shock waves in a strongly coupled dusty plasma  

Science Conference Proceedings (OSTI)

A strongly coupled dusty plasma containing strongly correlated negatively charged dust grains and weakly correlated (Maxwellian) electrons and ions has been considered. The effects of polarization force (which arises due to the interaction between thermal ions and highly negatively charged dust grains) and effective dust temperature (which arises from the electrostatic interactions among highly negatively charged dust and from the dust thermal pressure) on the dust-acoustic (DA) solitary and shock waves propagating in such a strongly coupled dusty plasma are taken into account. The DA solitary and shock waves are found to exist with negative potential only. It has been shown that the strong correlation among the charged dust grains is a source of dissipation and is responsible for the formation of the DA shock waves. It has also been shown that the effects of polarization force and effective dust-temperature significantly modify the basic features (e.g., amplitude, width, and speed) of the DA solitary and shock waves. It has been suggested that a laboratory experiment be performed to test the theory presented in this work.

Mamun, A. A.; Ashrafi, K. S.; Shukla, P. K. [Department of Physics, Jahangirnagar University, Savar, Dhaka 1342 (Bangladesh); RUB International Chair, International Centre for Advanced Studies in Physical Sciences, Faculty of Physics and Astronomy, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

2010-08-15T23:59:59.000Z

180

Pressure reducing regulator  

DOE Patents (OSTI)

A pressure reducing regulator that controls its downstream or outlet pressure to a fixed fraction of its upstream or inlet pressure is disclosed. The regulator includes a housing which may be of a titanium alloy, within which is located a seal or gasket at the outlet end which may be made of annealed copper, a rod, and piston, each of which may be made of high density graphite. The regulator is insensitive to temperature by virtue of being without a spring or gas sealed behind a diaphragm, and provides a reference for a system in which it is being used. The rod and piston of the regulator are constructed, for example, to have a 1/20 ratio such that when the downstream pressure is less than 1/20 of the upstream pressure the regulator opens and when the downstream pressure exceeds 1/20 of the upstream pressure the regulator closes. 10 figs.

Whitehead, J.C.; Dilgard, L.W.

1995-10-10T23:59:59.000Z

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Reducing Leaking Electricity  

NLE Websites -- All DOE Office Websites (Extended Search)

4 4 Reducing Leaking Electricity Figure 1. Full and standby power draws of some compact audio systems. A surprisingly large number of appliances-from computer peripherals to cable TV boxes to radios-consume electricity even after they have been switched off. Other appliances, such as cordless telephones, remote garage door openers, and battery chargers don't get switched off but draw power even when they are not performing their principal functions. The energy used while the appliance is switched off or not performing its primary purpose is called "standby consumption" or "leaking electricity." This consumption allows TVs, VCRs and garage-door openers to be ready for instant-on with a remote control, microwave ovens to display a digital

182

GRAIN SORTING IN COMETARY DUST FROM THE OUTER SOLAR NEBULA  

SciTech Connect

Most young stars are surrounded by a disk of gas and dust. Close to the hot stars, amorphous dust grains from the parent molecular cloud are reprocessed into crystals that are then distributed throughout the accretion disk. In some disks, there is a reduction in crystalline grain size with heliocentric distance from the star. We investigated crystalline grain size distributions in chondritic porous (CP) interplanetary dust particles (IDPs) believed to be from small, icy bodies that accreted in outer regions of the solar nebula. The grains are Mg-rich silicates and Fe-rich sulfides, the two most abundant minerals in CP IDPs. We find that they are predominantly <0.25 {mu}m in radius with a mean grain size that varies from one CP IDP to another. We report a size-density relationship between the silicates and sulfides. A similar size-density relationship between much larger silicate and sulfide grains in meteorites from the asteroid belt is ascribed to aerodynamic sorting. Since the silicate and sulfide grains in CP IDPs are theoretically too small for aerodynamic sorting, their size-density relationship may be due to another process capable of sorting small grains.

Wozniakiewicz, P. J.; Bradley, J. P.; Ishii, H. A. [Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Brownlee, D. E. [Department of Astronomy, University of Washington, Seattle, WA (United States); Kearsley, A. T. [Department of Mineralogy, Natural History Museum, London SW7 5BD (United Kingdom); Burchell, M. J.; Price, M. C., E-mail: P.Wozniakiewicz@kent.ac.uk [School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH (United Kingdom)

2012-12-01T23:59:59.000Z

183

The Use of Oil Refinery Wastes as a Dust Suppression Surfactant for Use in Mining  

Science Conference Proceedings (OSTI)

In this research, the suitability of a selection of petroleum refinery wastes as a dust suppressant were examined. Dust is a significant problem in surface and underground mining mainly because of its adverse effects on human health and machinery. Hence, dust control and suppression is a vital part of mine planning for mining engineers. Water is the oldest and the cheapest suppressant in dealing with the mine dusts. However, surfactant use has recently been used for a wider range of applications in the mining industry. In order to carry out laboratory experiments, a dust chamber was designed and manufactured. The chamber has an inlet for coal dust entrance and a nozzle for spraying water and the oil refinery wastes. Water and the surfactants were mixed at various ratios and then sprayed onto the coal dusts within the cell. Dust concentration was measured systematically to determine the effects of surfactant containing solution on the coal dust and the data obtained by the measurements were analyzed. The results showed that the oil refinery wastes could be used as a dust suppressant, which may create an economical utilization for the wastes concerned.

Dixon-Hardy, D.W.; Beyhan, S.; Ediz, I.G.; Erarslan, K. [University of Leeds, Leeds (United Kingdom)

2008-10-15T23:59:59.000Z

184

The collision effect between dust grains and ions to the dust ion acoustic waves in a dusty plasma  

Science Conference Proceedings (OSTI)

Damping solitary wave in dusty plasma is studied by considering the collision effect between dust grains and ions. It can be described by a KdV type equation in which a damping term of {phi}{sup 2} exist. It is found that both the amplitude and propagation velocity of the solitary wave decrease with time exponentially. Our results are compared with another KdV type equation with the damping term of {phi}. It is noted that the damping rate of the KdV type equation with the damping term of {phi}{sup 2} is larger than that with the term of {phi}. It is found that the damping rate is proportional to the collision frequency between dust grains and ions.

Yang Xue; Wang Canglong; Liu Congbo; Zhang Jianrong; Shi Yuren; Duan Wenshan [College of Physics and Electronic Engineering and Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou 730070 (China) and Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Yang Lei [College of Physics and Electronic Engineering and Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou 730070 (China) and Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Department of Physics, Lanzhou University, Lanzhou 730000 (China)

2012-10-15T23:59:59.000Z

185

A Comparison of "Total Dust" and Inhalable Personal Sampling for Beryllium Exposure.  

SciTech Connect

In 2009, the American Conference of Governmental Industrial Hygienists (ACGIH) reduced the Beryllium (Be) 8-hr Time Weighted Average Threshold Limit Value (TLV-TWA) from 2.0 {micro}g/m{sup 3} to 0.05 {micro}g/m{sup 3} with an inhalable 'I' designation in accordance with ACGIH's particle size-selective criterion for inhalable mass. Currently, per the Department of Energy (DOE) requirements, the Lawrence Livermore National Laboratory (LLNL) is following the Occupational Health and Safety Administration (OSHA) Permissible Exposure Limit (PEL) of 2.0 {micro}g/m{sup 3} as an 8-hr TWA, which is also the 2005 ACGIH TLV-TWA, and an Action Level (AL) of 0.2 {micro}g/m{sup 3} and sampling is performed using the 37mm (total dust) sampling method. Since DOE is considering adopting the newer 2009 TLV guidelines, the goal of this study was to determine if the current method of sampling using the 37mm (total dust) sampler would produce results that are comparable to what would be measured using the IOM (inhalable) sampler specific to the application of high energy explosive work at LLNL's remote experimental test facility at Site 300. Side-by-side personal sampling using the two samplers was performed over an approximately two-week period during chamber re-entry and cleanup procedures following detonation of an explosive assembly containing Beryllium (Be). The average ratio of personal sampling results for the IOM (inhalable) vs. 37-mm (total dust) sampler was 1.1:1 with a P-value of 0.62, indicating that there was no statistically significant difference in the performance of the two samplers. Therefore, for the type of activity monitored during this study, the 37-mm sampling cassette would be considered a suitable alternative to the IOM sampler for collecting inhalable particulate matter, which is important given the many practical and economic advantages that it presents. However, similar comparison studies would be necessary for this conclusion to be applied to other types of activities, where earlier studies have shown that the IOM sampler tends to collect higher concentrations of Be compared to the 37-mm cassette, which could complicate compliance with what is already an extremely low exposure limit.

Carter, C M

2012-04-25T23:59:59.000Z

186

Stewarding a Reduced Stockpile  

Science Conference Proceedings (OSTI)

The future of the US nuclear arsenal continues to be guided by two distinct drivers: the preservation of world peace and the prevention of further proliferation through our extended deterrent umbrella. Timely implementation of US nuclear policy decisions depends, in part, on the current state of stockpile weapons, their delivery systems, and the supporting infrastructure within the Department of Defense (DoD) and the Department of Energy's National Nuclear Security Administration (NNSA). In turn, the present is a product of past choices and world events. Now more than ever, the nuclear weapons program must respond to the changing global security environment and to increasing budget pressures with innovation and sound investments. As the nation transitions to a reduced stockpile, the successes of the Stockpile Stewardship Program (SSP) present options to transition to a sustainable complex better suited to stockpile size, national strategic goals and budgetary realities. Under any stockpile size, we must maintain essential human capital, forefront capabilities, and have a right-sized effective production capacity. We present new concepts for maintaining high confidence at low stockpile numbers and to effectively eliminate the reserve weapons within an optimized complex. We, as a nation, have choices to make on how we will achieve a credible 21st century deterrent.

Goodwin, B T; Mara, G

2008-04-18T23:59:59.000Z

187

ITP Materials: Poster - Development of Materials Resistant to Metal Dusting Degradation  

NLE Websites -- All DOE Office Websites (Extended Search)

metal dusting phenomenon metal dusting phenomenon in simulated process environments ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ ITP Materials, Sensors, and Automation, and Glass Project and Portfolio Review Meeting, June 21-24, Arlington, Virginia. K. Natesan, Z. Zeng, and D. L. Rink Energy Technology Division, Argonne National Laboratory, Argonne, Illinois, 60439 Introduction Metal dusting is a metal loss process that occurs in hot reactive gases The prerequisite for metal dusting is that carbon activity in the gas phase has to be >>1 Metal ends up as fine powder Pitting and crevice attack are common forms

188

Clementine Observations of the Zodiacal Light and the Dust Content of the Inner Solar System  

E-Print Network (OSTI)

Using the Moon to occult the Sun, the Clementine spacecraft used its navigation cameras to map the inner zodiacal light at optical wavelengths over elongations of 3-30 degrees from the Sun. This surface brightness map is then used to infer the spatial distribution of interplanetary dust over heliocentric distances of about 10 solar radii to the orbit of Venus. We also apply a simple model that attributes the zodiacal light as being due to three dust populations having distinct inclination distributions, namely, dust from asteroids and Jupiter-family comets (JFCs), dust from Halley-type comets, and an isotropic cloud of dust from Oort Cloud comets. The best-fitting scenario indicates that asteroids + JFCs are the source of about 45% of the optical dust cross-section seen in the ecliptic at 1 AU, but that at least 89% of the dust cross-section enclosed by a 1 AU radius sphere is of a cometary origin. When these results are extrapolated out to the asteroid belt, we find an upper limit on the mass of the light-reflecting asteroidal dust that is equivalent to a 12 km asteroid, and a similar extrapolation of the isotropic dust cloud out to Oort Cloud distances yields a mass equivalent to a 30 km comet, although the latter mass is uncertain by orders of magnitude.

J. M. Hahn; H. A. Zook; B. Cooper; B. Sunkara

2002-04-07T23:59:59.000Z

189

Heterogeneous chemistry of atmospheric mineral dust particles and their resulting cloud-nucleation properties  

E-Print Network (OSTI)

global emissions of reactive chlorine from anthropogenic andnatural sources: Reactive Chlorine Emissions Inventory, J.Mineral dust is a sink for chlorine in the marine boundary

Sullivan, Ryan Christopher

2008-01-01T23:59:59.000Z

190

A Fluorescent Aerogel for Capture and Identification of Interplanetary and Interstellar Dust  

E-Print Network (OSTI)

Contemporary interstellar dust has never been analyzed in the laboratory, despite its obvious astronomical importance and its potential as a probe of stellar nucleosynthesis and galactic chemical evolution. Here we report the discovery of a novel fluorescent aerogel which is capable of capturing hypervelocity dust grains and passively recording their kinetic energies. An array of these “calorimetric” aerogel collectors in low earth orbit would lead to the capture and identification of large numbers of interstellar dust grains. Subject headings: astrochemistry — instrumentation: detectors — interplanetary medium — dust, extinction — meteors, meteoroids — techniques: image processing 1.

Gerardo Domínguez; Andrew J. Westphal; Mark L. F. Phillips; Steven M. Jones

2003-01-01T23:59:59.000Z

191

Coal dust exposure among power station workers during normal operations at Hatfield's Ferry Power Station.  

E-Print Network (OSTI)

??Changes in coal composition could produce higher levels of coal dust exposure thanthose found in the past at Hatfield's Ferry Power Station. Air sampling was… (more)

Lewis, Christian S.

2008-01-01T23:59:59.000Z

192

A dichotomy in the orientation of dust and radio jets in nearby low-power radio galaxies  

E-Print Network (OSTI)

We examine the properties of central dust in nearby quiescent and active early-type galaxies. The active galaxies are low-power radio galaxies with Fanaroff & Riley Type I or I/II radio jets. We focus on the comparison of the dust distributions in the active and quiescent galaxy samples and the relation between the radio jet and dust orientations. Our main observational conclusions are: (a) radio galaxies contain a higher fraction of regular dust 'ellipses' compared to quiescent galaxies which contain more often irregular dust distributions; (b) the morphology, size and orientation of dust ellipses and lanes in quiescent early-types and active early-types with kpc-scale radio jets is very similar; (c) dust ellipses are aligned with the major axis of the galaxy, dust lanes do not show a preferred alignment except for large (>kpc) dust lanes which are aligned with the minor axis of the galaxy. Dust morphologies can be classified as regular 'ellipses' and filamentary 'lanes'. We show that the dust ellipses are consistent with being nearly circular thin disks viewed at random viewing angles. The lanes are likely warped dust structures, which may be in the process of settling down to become regular disks or are being perturbed by a non-gravitational force. We use the observed dust-jet orientations to constrain the three-dimensional angle $\\theta_{\\rm DJ}$ between jet and dust. For dust-lane galaxies, the jet is approximately perpendicular to the dust structure, while for dust-ellipse galaxies there is a much wider distribution of $\\theta_{\\rm DJ}$. We discuss two scenarios that could explain the dust/jet/galaxy orientation dichotomy. (abridged)

Gijs Verdoes Kleijn; Tim de Zeeuw

2005-02-03T23:59:59.000Z

193

Influence of charging process and size distribution of dust grain on the electric conductivity of dusty plasma  

Science Conference Proceedings (OSTI)

The effects of dust size distribution and charging process of dust grains on the complex electric conductivity of dusty plasmas have been investigated in the present paper. Comparisons are made between real dusty plasma in which there are many different dust grain species and the mono-sized dusty plasma (MDP) in which there is only one kind of dust grain whose size is the average dust size. In some cases the complex electric conductivity of real dusty plasma is larger than that of MDP, while in other cases it is smaller than that of MDP, it depends on the dust size distribution function.

Duan Jizheng; Wang Canglong; Zhang Jianrong; Ma Shengqian; Hong Xueren; Sun Jianan [College of Physics and Electronic Engineering and Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou 730070 (China) and Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Duan Wenshan [College of Physics and Electronic Engineering and Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou 730070 (China) and Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 (China); Yang Lei [College of Physics and Electronic Engineering and Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou 730070 (China) and Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Department of Physics, Lanzhou University, Lanzhou 730000 (China)

2012-08-15T23:59:59.000Z

194

Novel methods for respirable dust removal. Final report  

SciTech Connect

Two novel devices with potential for controlling emissions of dust particles in the respirable size range (0.3 to 3 microns) are the electrostatically enhanced cyclone (or electrocyclone) and acoustic agglomeration. The electrocyclone combines electrostatic, inertial forces and larger unit size compared to conventional cyclones to achieve improved performance. The acoustic agglomerator uses an oscillating acoustic flow field to cause particle collision and agglomeration. The resulting large particles are then more readily separable by conventional methods. The application of these novel methods to respirable dust control in pressurized fluidized-bed combustion and conventional pulverized coal combustion for electric power generation is explored in this study. In a PFBC power plant, dust particles entrained in the combustion gases must be removed at high temperature and pressure in order to protect a gas turbine from erosion. A key technical issue in this application is whether the hot gas cleanup equipment can satisfy the NSPS, or whether supplementary stack gas cleanup, such as a baghouse, is required downstream of the gas turbine. The potential of both the electrocyclone and the acoustic agglomerator for achieving NSPS ahead of the gas turbine has been assessed. In conventional PC power plants, particulate cleanup is normally accomplished with electrostatic precipitators. However, plants burning low sulfur western coals have experienced difficulty achieving adequate particulate emissions control with electrostatic precipitators, due to the high resistivity of the coal ash. For these applications the electrocyclone or an acoustic agglomerator coupled with either an electrocyclone or more conventional removal technique, might prove attractive. The principal conclusions drawn from the work performed and the recommendations based on the results are detailed. (LTN)

1980-09-01T23:59:59.000Z

195

Dust Aerosol Impact on North Africa Climate: A GCM Investigation of Aerosol-Cloud-Radiation Interactions Using A-Train Satellite Data  

Science Conference Proceedings (OSTI)

The climatic effects of dust aerosols in North Africa have been investigated using the atmospheric general circulation model (AGCM) developed at the University of California, Los Angeles (UCLA). The model includes an efficient and physically based radiation parameterization scheme developed specifically for application to clouds and aerosols. Parameterization of the effective ice particle size in association with the aerosol indirect effect based on cloud and aerosol data retrieved from A-Train satellite observations have been employed in the climate model simulations. Offline simulations reveal that the direct solar, IR, and net forcings by dust aerosols generally increase with increasing aerosol optical depth (AOD). When the dust semi-direct effect is included with the presence of ice clouds, positive IR radiative forcing is enhanced, since ice clouds trap substantial IR radiation, while the positive solar forcing with dust aerosols alone has been changed to negative values due to the strong reflection of solar radiation by clouds, indicating that cloud forcing could exceed aerosol forcing. With the aerosol indirect effect, the net cloud forcing is generally reduced for ice water path (IWP) larger than 20 g m-2. The magnitude of the reduction increases with IWP. AGCM simulations show that the reduced ice crystal mean effective size due to the aerosol first indirect effect result in less OLR and net solar flux at the top of the atmosphere over the cloudy area of the North Africa region because ice clouds with smaller size trap more IR radiation and reflect more solar radiation. The precipitation in the same area, however, increases due to the aerosol indirect effect on ice clouds, corresponding to the enhanced convection as indicated by reduced OLR. The increased precipitation seems to be associated with enhanced ice water contents in this region. The 200 mb radiative heating rate shows more cooling with the aerosol indirect effect since greater cooling is produced at the cloud top with smaller ice crystal size. The 500 mb omega indicates strong upward motion, which, together with the increased cooling effect, results in the increased ice water contents. Adding the aerosol direct effect into the model simulation reduces the precipitation in the normal rainfall band over North Africa, where precipitation is shifted to the south and the northeast produced by the absorption of sunlight and the subsequent heating of the air column by dust particles. As a result, rainfall is drawn further inland to the northeast. This study represents the first attempt to quantify the climate impact of aerosol indirect effect using a GCM in connection with A-train satellite data. The parameterization for the aerosol first indirect effect developed in this study can be readily incorporated for application to any other GCMs.

Gu, Y.; Liou, K. N.; Jiang, Jonathan; Su, Hui; Liu, Xiaohong

2012-02-15T23:59:59.000Z

196

Particle creation in (2+1) circular dust collapse  

E-Print Network (OSTI)

We investigate the quantum particle creation during the circularly symmetric collapse of a 2+1 dust cloud, for the cases when the cosmological constant is either zero or negative. We derive the Ford-Parker formula for the 2+1 case, which can be used to compute the radiated quantum flux in the geometric optics approximation. It is shown that no particles are created when the collapse ends in a naked singularity, unlike in the 3+1 case. When the collapse ends in a BTZ black hole, we recover the expected Hawking radiation. 1

Sashideep Gutti; T. P. Singh

2007-01-01T23:59:59.000Z

197

Volumetric measurements of a spatially growing dust acoustic wave  

Science Conference Proceedings (OSTI)

In this study, tomographic particle image velocimetry (tomo-PIV) techniques are used to make volumetric measurements of the dust acoustic wave (DAW) in a weakly coupled dusty plasma system in an argon, dc glow discharge plasma. These tomo-PIV measurements provide the first instantaneous volumetric measurement of a naturally occurring propagating DAW. These measurements reveal over the measured volume that the measured wave mode propagates in all three spatial dimensional and exhibits the same spatial growth rate and wavelength in each spatial direction.

Williams, Jeremiah D. [Physics Department, Wittenberg University, Springfield, Ohio 45504 (United States)

2012-11-15T23:59:59.000Z

198

Collapsing Inhomogeneous Dust Fluid in the Background of Dark Energy  

E-Print Network (OSTI)

In the present work, gravitational collapse of an inhomogeneous spherical star model, consisting of inhomogeneous dust fluid (dark matter) in the background of dark energy is considered. The collapsing process is examined first separately for both dark matter and dark energy and then under the combined effect of dark matter and dark energy with or without interaction. The dark energy is considered in the form of perfect fluid and both marginally and non-marginally bound cases are considered for the collapsing model. Finally dark energy in the form of anisotropic fluid is investigated and it is found to be similar to ref. [12

Tanwi Bandyopadhyay; Subenoy Chakraborty

2006-05-11T23:59:59.000Z

199

Impact of Desert Dust Radiative Forcing on Sahel Precipitation: Relative Importance of Dust Compared to Sea Surface Temperature Variations, Vegetation Changes, and Greenhouse Gas Warming  

Science Conference Proceedings (OSTI)

The role of direct radiative forcing of desert dust aerosol in the change from wet to dry climate observed in the African Sahel region in the last half of the twentieth century is investigated using simulations with an atmospheric general ...

Masaru Yoshioka; Natalie M. Mahowald; Andrew J. Conley; William D. Collins; David W. Fillmore; Charles S. Zender; Dani B. Coleman

2007-04-01T23:59:59.000Z

200

Roles of saltation, sandblasting, and wind speed variability on mineral dust aerosol size distribution during the Puerto Rican Dust Experiment (PRIDE)  

E-Print Network (OSTI)

Plumes arriving at Puerto Rico during the night would not beD > 5 µm) modeled at Puerto Rico. Assuming that the coarsetechniques during the Puerto Rico Dust Experiment (PRIDE)

Grini, A; Zender, C S

2004-01-01T23:59:59.000Z

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201

Ice Nuclei in Marine Air: Biogenic Particles or Dust?  

Science Conference Proceedings (OSTI)

Ice nuclei impact clouds, but their sources and distribution in the atmosphere are still not well known. Particularly little attention has been paid to IN sources in marine environments, although evidence from field studies suggests that IN populations in remote marine regions may be dominated by primary biogenic particles associated with sea spray. In this exploratory model study, we aim to bring attention to this long-neglected topic and identify promising target regions for future field campaigns. We assess the likely global distribution of marine biogenic ice nuclei using a combination of historical observations, satellite data and model output. By comparing simulated marine biogenic immersion IN distributions and dust immersion IN distributions, we predict strong regional differences in the importance of marine biogenic IN relative to dust IN. Our analysis suggests that marine biogenic IN are most likely to play a dominant role in determining IN concentrations in near-surface-air over the Southern Ocean, so future field campaigns aimed at investigating marine biogenic IN should target that region. Climate related changes in the abundance and emission of biogenic marine IN could affect marine cloud properties, thereby introducing previously unconsidered feedbacks that influence the hydrological cycle and the Earth’s energy balance. Furthermore, marine biogenic IN may be an important aspect to consider in proposals for marine cloud brightening by artificial sea spray production.

Burrows, Susannah M.; Hoose, C.; Poschl, U.; Lawrence, M.

2013-01-11T23:59:59.000Z

202

Dust Grain-Size Distributions From MRN to MEM  

E-Print Network (OSTI)

Employing the Maximum Entropy Method algorithm, we fit interstellar extinction measurements which span the wavelength range 0.125-3 micron. We present a uniform set of MEM model fits, all using the same grain materials, optical constants and abundance constraints. In addition, we are taking advantage of improved UV and IR data and better estimates of the gas-to-dust ratio. The model fits cover the entire range of extinction properties that have been seen in the Galaxy and the Magellanic Clouds. The grain models employed for this presentation are the simplistic homogeneous spheres models (i.e., Mathis, Rumpl, & Nordsieck 1977) with two (graphite, silicate) or three (graphite, silicate, amorphous carbon) components. Though such usage is only a first step, the results do provide interesting insight into the use of grain size as a diagnostic of dust environment. We find that the SMC Bar extinction curve cannot be fit using carbon grains alone. This is a challenge to the recent observational result indicating little silicon depletion in the SMC.

Geoffrey C. Clayton; Michael J. Wolff; Ulysses J. Sofia; K. D. Gordon; K. A. Misselt

2003-01-24T23:59:59.000Z

203

Growth of Dust as the Initial Step Toward Planet Formation  

E-Print Network (OSTI)

We discuss the results of laboratory measurements and theoretical models concerning the aggregation of dust in protoplanetary disks, as the initial step toward planet formation. Small particles easily stick when they collide and form aggregates with an open, often fractal structure, depending on the growth process. Larger particles are still expected to grow at collision velocities of about 1m/s. Experiments also show that, after an intermezzo of destructive velocities, high collision velocities above 10m/s on porous materials again lead to net growth of the target. Considerations of dust-gas interactions show that collision velocities for particles not too different in surface-to-mass ratio remain limited up to sizes about 1m, and growth seems to be guaranteed to reach these sizes quickly and easily. For meter sizes, coupling to nebula turbulence makes destructive processes more likely. Global aggregation models show that in a turbulent nebula, small particles are swept up too fast to be consistent with observations of disks. An extended phase may therefore exist in the nebula during which the small particle component is kept alive through collisions driven by turbulence which frustrates growth to planetesimals until conditions are more favorable for one or more reasons.

C. Dominik; J. Blum; J. Cuzzi; G. Wurm

2006-02-28T23:59:59.000Z

204

Distribution of Cold dust in Orion A and B  

E-Print Network (OSTI)

Large scale far-infrared (FIR) observations of the Orion complex at 205 and 138 micron are presented with an aim of studying the distribution of cold (< 25 K) dust. The maps in these FIR bands extend over approximately 3600 sq. arcmin and cover regions around OMC-1, 2, 3 in Orion A and NGC 2023 and NGC 2024 in Orion B. Some limited regions have also been mapped at 57 micron. A total of 15 sources in Orion A and 14 in Orion B (south) have been identified from our FIR maps. Dust temperature distribution in both Orion A and Orion B (south) have been determined reliably using the maps at 205 & 138 micron obtained from simultaneous observations using almost identical beams (1.6 dia). These temperatures have been used to generate map of the optical depth at 150 micron, for the Orion B region. The coldest source detected is in OMC-3 and has a temperature of about 15 K. The diffuse FIR emission in the different sub-regions is found to vary between 25% to 50% of the total FIR emission from that sub-region.

Mookerjea, B; Rengarajan, T N; Tandon, S N; Verma, R P

2000-01-01T23:59:59.000Z

205

Distribution of Cold dust in Orion A and B  

E-Print Network (OSTI)

Large scale far-infrared (FIR) observations of the Orion complex at 205 and 138 micron are presented with an aim of studying the distribution of cold (< 25 K) dust. The maps in these FIR bands extend over approximately 3600 sq. arcmin and cover regions around OMC-1, 2, 3 in Orion A and NGC 2023 and NGC 2024 in Orion B. Some limited regions have also been mapped at 57 micron. A total of 15 sources in Orion A and 14 in Orion B (south) have been identified from our FIR maps. Dust temperature distribution in both Orion A and Orion B (south) have been determined reliably using the maps at 205 & 138 micron obtained from simultaneous observations using almost identical beams (1.6 dia). These temperatures have been used to generate map of the optical depth at 150 micron, for the Orion B region. The coldest source detected is in OMC-3 and has a temperature of about 15 K. The diffuse FIR emission in the different sub-regions is found to vary between 25% to 50% of the total FIR emission from that sub-region.

B. Mookerjea; S. K. Ghosh; T. N. Rengarajan; S. N. Tandon; R. P. Verma

2000-07-24T23:59:59.000Z

206

Anomalous kinetic energy of a system of dust particles in a gas discharge plasma  

SciTech Connect

The system of equations of motion of dust particles in a near-electrode layer of a gas discharge has been formulated taking into account fluctuations of the charge of a dust particle and the features of the nearelectrode layer of the discharge. The molecular dynamics simulation of the system of dust particles has been carried out. Performing a theoretical analysis of the simulation results, a mechanism of increasing the average kinetic energy of dust particles in the gas discharge plasma has been proposed. According to this mechanism, the heating of the vertical oscillations of dust particles is initiated by induced oscillations generated by fluctuations of the charge of dust particles, and the energy transfer from vertical to horizontal oscillations can be based on the parametric resonance phenomenon. The combination of the parametric and induced resonances makes it possible to explain an anomalously high kinetic energy of dust particles. The estimate of the frequency, amplitude, and kinetic energy of dust particles are close to the respective experimental values.

Norman, G. E., E-mail: norman@ihed.ras.ru; Stegailov, V. V., E-mail: stegailov@gmail.com; Timofeev, A. V., E-mail: timofeevalvl@gmail.com [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

2011-11-15T23:59:59.000Z

207

Understanding the Transport and Impact of African Dust on the Caribbean Basin  

Science Conference Proceedings (OSTI)

Every year huge quantities of soil dust are carried by winds from Africa, across the Atlantic, and to the Caribbean. No other ocean region is so extensively and persistently impacted by such high concentrations of dust, a region that extends over 7000 km ...

Joseph M. Prospero; Olga L. Mayol-Bracero

2013-09-01T23:59:59.000Z

208

The March 2009 Dust Event in Saudi Arabia: Precursor and Supportive Environment  

Science Conference Proceedings (OSTI)

A case study is presented of the environmental background for a massive Saudi Arabian dust storm event that took place on 10 and 11 March 2009. The dust storm was large enough to be clearly seen from outer space and caused a widespread heavy atmospheric ...

B. H. Alharbi; A. Maghrabi; N. Tapper

2013-04-01T23:59:59.000Z

209

Three-dimensional reconstruction of dust particle trajectories in the NSTXa... W. U. Boeglin,1  

E-Print Network (OSTI)

. Roquemore,2 and R. Maqueda3 1 Physics Department, Florida International University, 11200 SW 8th Street to be controlled for safety reasons.1 Research into dust behavior in fusion devices includes the formation of dust ac- curately the difference of the particle's brightness and the surrounding background light should

Princeton Plasma Physics Laboratory

210

Study on plasma parameters and dust charging in an electrostatically plugged multicusp plasma device  

Science Conference Proceedings (OSTI)

The effect of the electrostatic confinement potential on the charging of dust grains and its relationship with the plasma parameters has been studied in an electrostatically plugged multicusp dusty plasma device. Electrostatic plugging is implemented by biasing the electrically isolated magnetic multicusp channel walls. The experimental results show that voltage applied to the channel walls can be a controlling parameter for dust charging.

Kakati, B.; Kausik, S. S.; Saikia, B. K. [Centre of Plasma Physics, Institute for Plasma Research, Nazirakhat, Sonapur-782 402, Kamrup, Assam (India); Bandyopadhyay, M. [ITER-India, Institute for Plasma Research, Bhat, Gandhinagar- 382 428 (India)

2011-06-15T23:59:59.000Z

211

Constraining Oceanic dust deposition using surface 1 ocean dissolved Al 2  

E-Print Network (OSTI)

Constraining Oceanic dust deposition using surface 1 ocean dissolved Al 2 Qin Han, J. Keith Moore, Charles Zender, Chris Measures, David Hydes 3 Abstract 4 We use measurements of ocean surface dissolved Al and Deposition 6 (DEAD) model, to constrain dust deposition to the oceans. Our Al database contains 7 all

Zender, Charles

212

Generation of concentration density maxima of small dispersive coal dust particles in horizontal iodine air filter at air-dust aerosol blow  

E-Print Network (OSTI)

The spatial distributions of the small dispersive coal dust particles with the nano and micro sizes in the granular filtering medium with the cylindrical coal granules in the absorber in the horizontal iodine air filter during its long term operation at the nuclear power plant are researched. It is shown that the concentration density maxima of the small dispersive coal dust particles appear in the granular filtering medium with the cylindrical coal absorbent granules in the horizontal iodine air filter at an action by the air dust aerosol blow. The comparison of the measured aerodynamic resistances of the horizontal and vertical iodine air filters is conducted. The main conclusion is that the magnitude of the aerodynamic resistance of the horizontal iodine air filters is much smaller in comparison with the magnitude of the aerodynamic resistance of the vertical iodine air filters at the same loads of the air dust aerosol volumes. It is explained that the direction of the air dust aerosol blow and the direction of the gravitation force in the horizontal iodine air filter are orthogonal, hence the effective accumulation of the small dispersive coal dust particles takes place at the bottom of absorber in the horizontal iodine air filter. It is found that the air dust aerosol stream flow in the horizontal iodine air filter is not limited by the appearing structures, made of the precipitated small dispersive coal dust particles, in distinction from the vertical iodine air filter, in the process of long term operation of the iodine air filters at the nuclear power plant.

I. M. Neklyudov; O. P. Ledenyov; L. I. Fedorova; P. Ya. Poltinin

2013-06-11T23:59:59.000Z

213

Modeled Downward Transport of a Passive Tracer over Western North America during an Asian Dust Event in April 1998  

Science Conference Proceedings (OSTI)

An intense Gobi Desert dust storm in April 1998 loaded the midtroposphere with dust that was transported across the Pacific to western North America. The Mesoscale Compressible Community (MC2) model was used to investigate mechanisms causing ...

Joshua P. Hacker; Ian G. McKendry; Roland B. Stull

2001-09-01T23:59:59.000Z

214

Two Case Studies of the Transport of Dust Storm Aerosol and the Potential for Incorporation into Precipitation  

Science Conference Proceedings (OSTI)

To investigate the hypothesis that dust storms enhanced the calcium concentrations in precipitation in the mid-1950s, two case studies were performed for major dust events in the southern Plains of the United States during March and April of ...

Kevin G. Doty; Richard G. Semonin

1987-07-01T23:59:59.000Z

215

Examining the Effects of Dust Aerosols on Satellite Sea Surface Temperatures in the Mediterranean Sea Using the Medspiration Matchup Database  

Science Conference Proceedings (OSTI)

Dust aerosol plumes from the Sahara cover the Mediterranean Sea regularly during the summer months (June–August) and occasionally during other seasons. Dust can absorb infrared longwave radiation, thus causing a drop in sea surface temperature (...

Ana B. Ruescas; Manuel Arbelo; Jose A. Sobrino; Cristian Mattar

2011-05-01T23:59:59.000Z

216

Roles of polarization force and nonthermal electron on dust-acoustic waves in an inhomogeneous dusty plasma with positively charged dust  

Science Conference Proceedings (OSTI)

The influence of polarization force (PF) (arises due to dust density inhomogeneity), nonthermal electrons, and dust density inhomogeneity associated with positively charged dust on linear dust-acoustic (DA) waves in an inhomogeneous unmagnetized dusty plasma are investigated. By taking the normal mode analysis, the dispersion relation in such a non-Maxwellian inhomogeneous plasma is obtained, and that the dispersion properties of the DA waves are significantly modified by the presence of PF and nonthermal electrons. The PF is increased with the increase of nonthermal electrons. It is found that the phase speed of the DA waves is significantly decreased with the presence of PF and nonthermal electrons. The potential associated with the DA waves is de-enhanced with the increase of equilibrium dust number density. The role of positive dust number density on dispersion properties is also shown. The present findings relevant to different scenarios in laboratory and space dusty plasma, such as Martian ionosphere, solar flares, TEXTOR-94 tokamak plasmas, rf excited argon magnetoplasma, etc., can be useful to understand the properties of localized electrostatic disturbances in those dusty plasma system, are also briefly addressed.

Asaduzzaman, M.; Mamun, A. A. [Department of Physics, Jahangirnagar University, Savar, Dhaka 1342 (Bangladesh)

2012-09-15T23:59:59.000Z

217

Geek-Up[6.24.11]: Dust-sized 'Dragonfly' Device and Tiny Microvalves |  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Dust-sized 'Dragonfly' Device and Tiny Dust-sized 'Dragonfly' Device and Tiny Microvalves Geek-Up[6.24.11]: Dust-sized 'Dragonfly' Device and Tiny Microvalves June 24, 2011 - 7:15pm Addthis A computer simulation of the "dragonfly-inspired" device. | Courtesy of Sandia Laboratory A computer simulation of the "dragonfly-inspired" device. | Courtesy of Sandia Laboratory Niketa Kumar Niketa Kumar Public Affairs Specialist, Office of Public Affairs What are the key facts? A dust-size "dragonfly-inspired" device -- which won a Sandia Lab design contest -- may ultimately enable the creation of tiny microvalves for experiments in biological research laboratories and medical facilities. In Sandia National Laboratories' MEMS (microelectromechanical system) University Alliance design contest, a dust-sized dragonfly and a super

218

THE PHYSICS OF PROTOPLANETESIMAL DUST AGGLOMERATES. VII. THE LOW-VELOCITY COLLISION BEHAVIOR OF LARGE DUST AGGLOMERATES  

Science Conference Proceedings (OSTI)

We performed micro-gravity collision experiments in our laboratory drop tower using 5 cm sized dust agglomerates with volume filling factors of 0.3 and 0.4, respectively. This work is an extension of our previous experiments reported in Beitz et al. to aggregates of more than one order of magnitude higher masses. The dust aggregates consisted of micrometer-sized silica particles and were macroscopically homogeneous. We measured the coefficient of restitution for collision velocities ranging from 1 cm s{sup -1} to 0.5 m s{sup -1}, and determined the fragmentation velocity. For low velocities, the coefficient of restitution decreases with increasing impact velocity, in contrast to findings by Beitz et al. At higher velocities, the value of the coefficient of restitution becomes constant, before the aggregates break at the onset of fragmentation. We interpret the qualitative change in the coefficient of restitution as the transition from a solid-body-dominated to a granular-medium-dominated behavior. We complement our experiments by molecular-dynamics simulations of porous aggregates and obtain a reasonable match to the experimental data. We discuss the importance of our experiments for protoplanetary disks, debris disks, and planetary rings. This work is an extension to the previous work of our group and gives new insight into the velocity dependency of the coefficient of restitution due to improved measurements, better statistics, and a theoretical approach.

Schraepler, Rainer; Blum, Juergen [Institut fuer Geophysik und extraterrestrische Physik, University of Braunschweig Mendelssohnstr. 3, D-38106 Braunschweig (Germany); Seizinger, Alexander; Kley, Wilhelm, E-mail: r.schraepler@tu-bs.de [Institut fuer Astronomie und Astrophysik, University of Tuebingen Auf der Morgenstelle 10, D-72076 Tuebingen (Germany)

2012-10-10T23:59:59.000Z

219

Oxygen-reducing catalyst layer  

DOE Patents (OSTI)

An oxygen-reducing catalyst layer, and a method of making the oxygen-reducing catalyst layer, where the oxygen-reducing catalyst layer includes a catalytic material film disposed on a substrate with the use of physical vapor deposition and thermal treatment. The catalytic material film includes a transition metal that is substantially free of platinum. At least one of the physical vapor deposition and the thermal treatment is performed in a processing environment comprising a nitrogen-containing gas.

O' Brien, Dennis P. (Maplewood, MN); Schmoeckel, Alison K. (Stillwater, MN); Vernstrom, George D. (Cottage Grove, MN); Atanasoski, Radoslav (Edina, MN); Wood, Thomas E. (Stillwater, MN); Yang, Ruizhi (Halifax, CA); Easton, E. Bradley (Halifax, CA); Dahn, Jeffrey R. (Hubley, CA); O' Neill, David G. (Lake Elmo, MN)

2011-03-22T23:59:59.000Z

220

Reduce Air Infiltration in Furnaces  

Science Conference Proceedings (OSTI)

This DOE Industrial Technologies Program tip sheet describes how to save energy and costs by reducing air infiltration in industrial furnaces; tips include repairing leaks and increasing insulation.

Not Available

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Harrison transformation of hyperelliptic solutions and charged dust disks  

E-Print Network (OSTI)

We use a Harrison transformation on solutions to the stationary axisymmetric Einstein equations to generate solutions of the Einstein-Maxwell equations. The case of hyperelliptic solutions to the Ernst equation is studied in detail. Analytic expressions for the metric and the multipole moments are obtained. As an example we consider the transformation of a family of counter-rotating dust disks. The resulting solutions can be interpreted as disks with currents and matter with a purely azimuthal pressure or as two streams of freely moving charged particles. We discuss interesting limiting cases as the extreme limit where the charge becomes identical to the mass, and the ultrarelativistic limit where the central redshift diverges.

C. Klein

2005-12-22T23:59:59.000Z

222

Dust-to-gas ratio and star formation history of blue compact dwarf galaxies  

E-Print Network (OSTI)

This paper investigates the origin of the observed large variety in dust-to-gas ratio among blue compact dwarf galaxies (BCDs). By applying our chemical evolution model, we find that the dust destruction can largely suppress the dust-to-gas ratio when the metallicity of a BCD reaches $12+\\log{\\rm (O/H)}\\sim 8$, i.e., a typical metallicity level of BCDs. We also show that dust-to-gas ratio is largely varied owing to the change of dust destruction efficiency that has two effects: (i) a significant contribution of Type Ia supernovae to total supernova rate; (ii) variation of gas mass contained in a star-forming region. While mass loss from BCDs was previously thought to be the major cause for the variance of dust-to-gas ratio, we suggest that the other two effects are also important. We finally discuss the intermittent star formation history, which naturally explains the large dispersion of dust-to-gas ratio among BCDs.

H. Hirashita; Y. Y. Tajiri; H. Kamaya

2002-04-18T23:59:59.000Z

223

Dispersion relation for pure dust Bernstein waves in a non-Maxwellian magnetized dusty plasma  

SciTech Connect

Pure dust Bernstein waves are investigated using non-Maxwellian kappa and (r,q) distribution functions in a collisionless, uniform magnetized dusty plasma. Dispersion relations for both the distributions are derived by considering waves whose frequency is of the order of dust cyclotron frequency, and dispersion curves are plotted. It is observed that the propagation band for dust Bernstein waves is rather narrow as compared with that of the electron Bernstein waves. However, the band width increases for higher harmonics, for both kappa and (r,q) distributions. Effect of dust charge on dispersion curves is also studied, and one observes that with increasing dust charge, the dispersion curves shift toward the lower frequencies. Increasing the dust to ion density ratio ((n{sub d0}/n{sub i0})) causes the dispersion curve to shift toward the higher frequencies. It is also found that for large values of spectral index kappa ({kappa}), the dispersion curves approach to the Maxwellian curves. The (r,q) distribution approaches the kappa distribution for r = 0, whereas for r > 0, the dispersion curves show deviation from the Maxwellian curves as expected. Relevance of this work can be found in astrophysical plasmas, where non-Maxwellian velocity distributions as well as dust particles are commonly observed.

Deeba, F. [National Tokamak Fusion Program, PAEC, P.O. Box 3329, Islamabad 44000 (Pakistan); Department of Physics, G.C. University, Lahore 54000 (Pakistan); Ahmad, Zahoor [National Tokamak Fusion Program, PAEC, P.O. Box 3329, Islamabad 44000 (Pakistan); Murtaza, G. [Salam Chair in Physics, G.C. University, Lahore 54000 (Pakistan)

2011-07-15T23:59:59.000Z

224

Coal dust contiguity-induced changes in the concentration of TNF- and NF- B p65 on the ocular surface  

Science Conference Proceedings (OSTI)

To observe the influence of coal dust on ocular surface of coal miners and rabbits with coal dust contiguity on expression TNF- and NF- Bp65 and dry eye occurrence. Expression TNF- and NF- Bp65 in ocular surface were determined. Results showed tear production, BUT and lysozyme decreased for coal miners and rabbits with coal dust contiguity. Coal dust exposure was linked to development of xerophthalmia, and induced a higher expression of NF- B p65 and TNF- perhaps as a mechanism to resist coal dust ocular surface injury.

Sun, Z.Y.; Hong, J.; Liu, Z.Y.; Jin, X.D.; Gu, C.H. [China Medical University, Shenyang (China)

2009-07-01T23:59:59.000Z

225

Apparatus for dusting off gas by filtration and aspiration cleaning of filter, and application to combustion gases  

SciTech Connect

Method and apparatus for dusting off gases by filtration and cleaning of filter by aspiration and application thereof to combustion gases are disclosed. This invention relates to the filtration of dust loaded gases, and, in particular, combustion gases in the hot state. It consists of passing gases to be dusted off from top to bottom over a bed of pulverulent material, in particular, a sand bed and cleaning the upper layer of said bed by aspiration of dusts deposited thereon. This invention is particularly adapted for dusting off combustion gases from boilers or thermal power stations or gases to be supplied to gas turbines.

Merry, J.

1982-07-06T23:59:59.000Z

226

EFFECT OF DUST ON Ly{alpha} PHOTON TRANSFER IN AN OPTICALLY THICK HALO  

SciTech Connect

We investigate the effects of dust on Ly{alpha} photons emergent from an optically thick medium by solving the integro-differential equation of radiative transfer of resonant photons. To solve the differential equations numerically, we use the weighted essentially non-oscillatory method. Although the effects of dust on radiative transfer are well known, the resonant scattering of Ly{alpha} photons makes the problem non-trivial. For instance, if the medium has an optical depth of dust absorption and scattering of {tau}{sub a} >> 1, {tau} >> 1, and {tau} >> {tau}{sub a}, the effective absorption optical depth in a random walk scenario would be equal to {radical}({tau}{sub a}({tau}{sub a}+{tau})). We show, however, that for a resonant scattering at frequency {nu}{sub 0}, the effective absorption optical depth would be even larger than {tau}({nu}{sub 0}). If the cross section of dust scattering and absorption is frequency-independent, the double-peaked structure of the frequency profile given by the resonant scattering is basically dust-independent. That is, dust causes neither narrowing nor widening of the width of the double-peaked profile. One more result is that the timescales of the Ly{alpha} photon transfer in an optically thick halo are also basically independent of the dust scattering, even when the scattering is anisotropic. This is because those timescales are mainly determined by the transfer in the frequency space, while dust scattering, either isotropic or anisotropic, does not affect the behavior of the transfer in the frequency space when the cross section of scattering is wavelength-independent. This result does not support the speculation that dust will lead to the smoothing of the brightness distribution of a Ly{alpha} photon source with an optically thick halo.

Yang Yang; Shu Chiwang [Division of Applied Mathematics, Brown University, Providence, RI 02912 (United States); Roy, Ishani [Computing Laboratory, University of Oxford, Oxford, OX1 3QD (United Kingdom); Fang Lizhi [Department of Physics, University of Arizona, Tucson, AZ 85721 (United States)

2011-10-01T23:59:59.000Z

227

Extraplanar Dust in the Edge-On Spiral NGC 891 1  

E-Print Network (OSTI)

We present high-resolution (0.6 ? ?-0.65 ? ? ) optical broad-band images of the edge-on Sb galaxy NGC 891 obtained with the WIYN 3.5-m telescope. These BVR images reveal a complex network of hundreds of dust absorbing structures far from the mid-plane of the galaxy. The dust structures have a wide range of morphologies and are clearly visible to |z | ? 1021 cm ?2, with masses estimated to be more than 2 × 10 5 ? 5 × 10 6 M?, assuming Galactic gas-to-dust relationships. The gravitational potential energies of the individual dust structures, given their observed heights and derived masses, lie in the range of 20 ? 200 × 10 51 ergs, which represents the energy input of at least tens to hundreds of supernovae. Rough number counts of extraplanar dust features find ?>120 structures at |z |> 400 pc with apparent B-band extinction ?> 0.25 mag. If these have similar properties to those structures studied in detail, the mass of high-z gas associated with extraplanar dust in NGC 891 likely exceeds 2 × 10 8 M?, which is ?2 % of the total neutral ISM mass of the galaxy. The absorbing properties of extraplanar dust structures in NGC 891 are best fit with RV ? AV /E(B ? V) = 3.6 ± 0.4. A comparison of the new WIYN images with an archival Hubble Space Telescope image of the central region of NGC 891 suggests that the quantities we measure for the extraplanar dust features are not seriously affected by atmospheric blurring in the WIYN images. Some of the dust features seen in NGC 891 suggest supernova-driven galactic fountain or chimney phenomena are responsible for their production and are clearly associated with ionized gas structures thought to be tracing the violent disk-halo interface of this galaxy. However, other structures are not so readily associated with

J. Christopher Howk; Blair D. Savage

1997-01-01T23:59:59.000Z

228

Water uptake of clay and desert dust aerosol particles at sub- and supersaturated water vapor conditions  

SciTech Connect

Airborne mineral dust particles serve as cloud condensation nuclei (CCN), thereby influencing the formation and properties of warm clouds. It is therefore of particular interest how dust aerosols with different mineralogy behave when exposed to high relative humidity (RH) or supersaturation with respect to liquid water similar to atmospheric conditions. In this study the sub-saturated hygroscopic growth and the supersaturated cloud condensation nucleus activity of pure clays and real desert dust aerosols was determined using a hygroscopicity tandem differential mobility analyzer (HTDMA) and a cloud condensation nuclei counter (CCNC), respectively. Five different illite, montmorillonite and kaolinite clay samples as well as three desert dust samples (Saharan dust (SD), Chinese dust (CD) and Arizona test dust (ATD)) were used. Aerosols were generated both with a wet and a dry disperser and the water uptake was parameterized via the hygroscopicity parameter, ?. The hygroscopicity of dry generated dust aerosols was found to be negligible when compared to processed atmospheric aerosols, with CCNC derived ? values between 0.00 and 0.02. The latter value can be idealized as a particle consisting of 96.7% (by volume) insoluble material and ~3.3% ammonium sulfate. Pure clay aerosols were found to be generally less hygroscopic than real desert dust particles. All illite and montmorillonite samples had ?~0.003, kaolinites were least hygroscopic and had ?=0.001. SD (?=0.023) was found to be the most hygroscopic dry-generated desert dust followed by CD (?=0.007) and ATD (?=0.003). Wet-generated dust showed an increased water uptake when compared to dry-generated samples. This is considered to be an artifact introduced by redistribution of soluble material between the particles while immersed in an aqueous medium during atomization, thus indicating that specification of the generation method is critically important when presenting such data. Any atmospheric processing of fresh mineral dust which leads to the addition of more than ~3% soluble material is expected to significantly enhance hygroscopicity and CCN activity.

Herich, Hanna; Tritscher, Torsten; Wiacek, Aldona; Gysel, Martin; Weingartner, E.; Lohmann, U.; Baltensperger, Urs; Cziczo, Daniel J.

2009-11-01T23:59:59.000Z

229

Direct observation of dynamics of single spinning dust grains in weakly magnetized complex plasma  

SciTech Connect

The rotational dynamics of single dust grains in a weak magnetic field is investigated on a kinetic level. Experiments reveal spin-up of spherical dust grains and alignment of their magnetic moments parallel to the magnetic induction vector. The angular velocity of spinning prolate grains varies as magnetic induction increases to 250 G. Spinning dust grains are found to flip over only when the magnetic field magnitude is changing. The results demonstrate that dusty plasma has paramagnetic properties. Qualitative interpretations are proposed to explain newly discovered phenomena.

Dzlieva, E. S.; Karasev, V. Yu., E-mail: plasmadust@yandex.ru [St. Petersburg State University, Institute of Physics (Russian Federation); Petrov, O. F. [Russian Academy of Sciences, Institute for High Energy Densities, Joint Institute for High Temperatures (Russian Federation)

2012-01-15T23:59:59.000Z

230

African Dust Influence on Atlantic Hurricane Activity and the Peculiar Behaviour of Category 5 Hurricanes  

E-Print Network (OSTI)

We study the specific influence of African dust on each one of the categories of Atlantic hurricanes. By applying wavelet analysis, we find a strong decadal modulation of African dust on Category 5 hurricanes and an annual modulation on all other categories of hurricanes. We identify the formation of Category 5 hurricanes occurring mainly around the decadal minimum variation of African dust and in deep water areas of the Atlantic Ocean, where hurricane eyes have the lowest pressure. According to our results, future tropical cyclones will not evolve to Category 5 until the next decadal minimum that is, by the year 2015 +/- 2.

Herrera, Victor M Velasco; H., Graciela Velasco; Gonzalez, Laura Luna

2010-01-01T23:59:59.000Z

231

Ion beam driven ion-acoustic waves in a plasma cylinder with negatively charged dust grains  

SciTech Connect

An ion beam propagating through a magnetized potassium plasma cylinder having negatively charged dust grains drives electrostatic ion-acoustic waves to instability via Cerenkov interaction. The phase velocity of sound wave increases with the relative density of negatively charged dust grains. The unstable wave frequencies and the growth rate increase, with the relative density of negatively charged dust grains. The growth rate of the unstable mode scales as one-third power of the beam density. The real part of frequency of the unstable mode increases with the beam energy and scales as almost the one-half power of the beam energy.

Sharma, Suresh C.; Walia, Ritu [Department of Physics, Maharaja Agrasen Institute of Technology, PSP Area Plot No.-1, Sector-22, Rohini, Delhi 110 086 (India); Sharma, Kavita [Department of Physics, Bhagwan Parshuram Institute of Technology, Sector-17, Rohini, New Delhi 110 089 (India)

2012-07-15T23:59:59.000Z

232

Generation of concentration density maxima of small dispersive coal dust particles in horizontal iodine air filter at air-dust aerosol blow  

E-Print Network (OSTI)

The spatial distributions of the small dispersive coal dust particles with the nano and micro sizes in the granular filtering medium with the cylindrical coal granules in the absorber in the horizontal iodine air filter during its long term operation at the nuclear power plant are researched. It is shown that the concentration density maxima of the small dispersive coal dust particles appear in the granular filtering medium with the cylindrical coal absorbent granules in the horizontal iodine air filter at an action by the air dust aerosol blow. The comparison of the measured aerodynamic resistances of the horizontal and vertical iodine air filters is conducted. The main conclusion is that the magnitude of the aerodynamic resistance of the horizontal iodine air filters is much smaller in comparison with the magnitude of the aerodynamic resistance of the vertical iodine air filters at the same loads of the air dust aerosol volumes. It is explained that the direction of the air dust aerosol blow and the directi...

Neklyudov, I M; Fedorova, L I; Poltinin, P Ya

2013-01-01T23:59:59.000Z

233

Reduced shedding regenerator and method  

DOE Patents (OSTI)

A reduced shedding regenerator and method are disclosed with regenerator surfaces to minimize shedding of particles from the regenerator thereby alleviating a source of potential damage and malfunction of a thermal regenerative machine using the regenerator.

Qiu, Songgang (Richland, WA); Augenblick, John E. (Richland, WA); Erbeznik, Raymond M. (Kennewick, WA)

2007-05-22T23:59:59.000Z

234

Tracking shocked dust: State estimation for a complex plasma during a shock wave  

SciTech Connect

We consider a two-dimensional complex (dusty) plasma crystal excited by an electrostatically-induced shock wave. Dust particle kinematics in such a system are usually determined using particle tracking velocimetry. In this work we present a particle tracking algorithm which determines the dust particle kinematics with significantly higher accuracy than particle tracking velocimetry. The algorithm uses multiple extended Kalman filters to estimate the particle states and an interacting multiple model to assign probabilities to the different filters. This enables the determination of relevant physical properties of the dust, such as kinetic energy and kinetic temperature, with high precision. We use a Hugoniot shock-jump relation to calculate a pressure-volume diagram from the shocked dust kinematics. Calculation of the full pressure-volume diagram was possible with our tracking algorithm, but not with particle tracking velocimetry.

Oxtoby, Neil P.; Ralph, Jason F.; Durniak, Celine; Samsonov, Dmitry [Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, L69 3GJ (United Kingdom)

2012-01-15T23:59:59.000Z

235

Radiative Forcing of a Tropical Direct Circulation by Soil Dust Aerosols  

Science Conference Proceedings (OSTI)

The effect of soil dust aerosols upon the tropical climate is estimated by forcing a simple model of a tropical direct circulation. The model consists of a region vertically mixed by deep convection and a nonconvecting region, for which budgets ...

R. L. Miller; I. Tegen

1999-07-01T23:59:59.000Z

236

Properties of Sharav (Khamsin) Dust–Comparison of Optical and Direct Sampling Data  

Science Conference Proceedings (OSTI)

Simultaneous measurements of optical depth and Size distribution in a dust storm are presented. The measured and derived properties of the aerosol are compared with each other and with other results published in the scientific literature. We ...

Zev Levin; Joachim H. Joseph; Yuri Mekler

1980-04-01T23:59:59.000Z

237

High-Resolution Measurement of Size Distributions of Asian Dust Using a Coulter Multisizer  

Science Conference Proceedings (OSTI)

A Coulter Multisizer, which is based on the electrical sensing zone (ESZ) or the Coulter principle, was used to measure the size distribution of Asian dust. Coulter Multisizer analysis provides high-resolution size measurements of water-insoluble ...

Hiroshi Kobayashi; Kimio Arao; Toshiyuki Murayama; Kengo Iokibe; Ryuji Koga; Masataka Shiobara

2007-02-01T23:59:59.000Z

238

Influence of Mesoscale Dynamics and Turbulence on Fine Dust Transport in Owens Valley  

Science Conference Proceedings (OSTI)

Fine dust particles emitted from Owens (dry) Lake in California documented during the Terrain-Induced Rotor Experiment (T-REX) of 2006 have been examined using surface observations and a mesoscale aerosol model. Air quality stations around Owens (...

Qingfang Jiang; Ming Liu; James D. Doyle

2011-01-01T23:59:59.000Z

239

The WIRED Survey. IV. New Dust Disks from the McCook & Sion White Dwarf Catalog  

E-Print Network (OSTI)

We have compiled photometric data from the Wide-field Infrared Survey Explorer All Sky Survey and other archival sources for the more than 2200 objects in the original McCook & Sion Catalog of Spectroscopically Identified White Dwarfs. We applied color-selection criteria to identify 28 targets whose infrared spectral energy distributions depart from the expectation for the white dwarf photosphere alone. Seven of these are previously known white dwarfs with circumstellar dust disks, five are known central stars of planetary nebulae, and six were excluded for being known binaries or having possible contamination of their infrared photometry. We fit white dwarf models to the spectral energy distributions of the remaining ten targets, and find seven new candidates with infrared excess suggesting the presence of a circumstellar dust disk. We compare the model dust disk properties for these new candidates with a comprehensive compilation of previously published parameters for known white dwarfs with dust disks....

Hoard, D W; Wachter, Stefanie; Leisawitz, David T; Cohen, Martin

2013-01-01T23:59:59.000Z

240

Tanpopo cosmic dust collector: Silica aerogel production and bacterial DNA contamination analysis  

E-Print Network (OSTI)

Hydrophobic silica aerogels with ultra-low densities have been designed and developed as cosmic dust capture media for the Tanpopo mission which is proposed to be carried out on the International Space Station. Glass particles as a simulated cosmic dust with 30 \\mu m in diameter and 2.4 g/cm^3 in density were successfully captured by the novel aerogel at a velocity of 6 km/s. Background levels of contaminated DNA in the ultra-low density aerogel were lower than the detection limit of a polymerase chain reaction assay. These results show that the manufactured aerogel has good performance as a cosmic dust collector and sufficient quality in respect of DNA contamination. The aerogel is feasible for the biological analyses of captured cosmic dust particles in the astrobiological studies.

Tabata, Makoto; Yokobori, Shin-ichi; Kawai, Hideyuki; Takahashi, Jun-ichi; Yano, Hajime; Yamagishi, Akihiko

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Radiative Forcing of Saharan Dust: GOCART Model Simulations Compared with ERBE Data  

Science Conference Proceedings (OSTI)

This study uses information on Saharan aerosol from a dust transport model to calculate radiative forcing values. The transport model is driven by assimilated meteorological fields from the Goddard Earth Observing System Data Assimilation System. ...

Clark J. Weaver; Paul Ginoux; N. Christina Hsu; Ming-Dah Chou; Joanna Joiner

2002-02-01T23:59:59.000Z

242

Comparison Between Dust Particle Generation In CH4 or CH4/N2 Mixing RF Plasmas  

SciTech Connect

Dust particles have been spontaneously generated either in pure CH4 or in CH4/N2 r.f. plasmas. The dust particle formation results from homogeneous nucleation in the plasma and is detected by laser light scattering (Ar+, {lambda} = 514.5 nm). The temporal and spatial behaviour of dust particles is studied. In pure methane gas, particles are trapped in well defined clouds at the plasma sheath boundaries. In a CH4/N2 mixture, the nitrogen addition leads to an expansion of the clouds. For nitrogen contents higher than 50%, the space between the electrodes is nearly completely filled with dust particles leading to plasma instabilities and a void appears in the center of the discharge. The particles are spherical with diameters in the range 0.8-2 {mu}m. For nitrogen-rich plasmas, the particles growth is improved and leads to a rough shape with an orange-peel-type surface texture.

Pereira, Jeremy; Massereau-Guilbaud, Veronique; Geraud-Grenier, Isabelle; Plain, Andre [LASEP, Faculte des Sciences, Universite d'Orleans, Site de Bourges, rue G.Berger, BP 4043, 18028 Bourges Cedex (France)

2005-10-31T23:59:59.000Z

243

On Absorption by Circumstellar Dust, With the Progenitor of SN2012aw as a Case Study  

E-Print Network (OSTI)

We use the progenitor of SN2012aw to illustrate the consequences of modeling circumstellar dust using Galactic (interstellar) extinction laws that (1) ignore dust emission in the near-IR and beyond; (2) average over dust compositions, and (3) mis-characterize the optical/UV absorption by assuming that scattered photons are lost to the observer. The primary consequences for the progenitor of SN2012aw are that both the luminosity and the absorption are significantly over-estimated. In particular, the stellar luminosity is most likely in the range 10^4.8 0.3 micron) and total (absorption plus scattering) V-band optical depth (tau < 20). These do not include the contributions of dust emission, but provide a simple, physical alternative to incorrectly using interstellar extinction laws.

Kochanek, C S; Dai, X

2012-01-01T23:59:59.000Z

244

Award-winning alloys could reduce costs for chemical and petrochemical  

NLE Websites -- All DOE Office Websites (Extended Search)

Award-winning alloys could reduce costs for chemical and petrochemical Award-winning alloys could reduce costs for chemical and petrochemical industries Director's Welcome Organization Achievements Highlights Fact Sheets, Brochures & Other Documents Multimedia Library About Nuclear Energy Nuclear Reactors Designed by Argonne Argonne's Nuclear Science and Technology Legacy Opportunities within NE Division Visit Argonne Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Celebrating the 70th Anniversary of Chicago Pile 1 (CP-1) Argonne OutLoud on Nuclear Energy Argonne Energy Showcase 2012 Highlights Bookmark and Share Award-winning alloys could reduce costs for chemical and petrochemical industries This macrophotograph compares commercial nickel-based Alloy 600 (top) and Argonne's new alloy after 5,700 hours of exposure to the same metal-dusting environment at 593°C

245

Impact of the Desert Dust on the Summer Monsoon System over Southwestern North America  

SciTech Connect

The radiative forcing of dust emitted from the Southwest United States (US) deserts and its impact on monsoon circulation and precipitation over the North America monsoon (NAM) region are simulated using a coupled meteorology and aerosol/chemistry model (WRF-Chem) for 15 years (1995-2009). During the monsoon season, dust has a cooling effect (-0.90 W m{sup -2}) at the surface, a warming effect (0.40 W m{sup -2}) in the atmosphere, and a negative top-of-the-atmosphere (TOA) forcing (-0.50 W m{sup -2}) over the deserts on 24-h average. Most of the dust emitted from the deserts concentrates below 800 hPa and accumulates over the western slope of the Rocky Mountains and Mexican Plateau. The absorption of shortwave radiation by dust heats the lower atmosphere by up to 0.5 K day{sup -1} over the western slope of the Mountains. Model sensitivity simulations with and without dust for 15 summers (June-July-August) show that dust heating of the lower atmosphere over the deserts strengthens the low-level southerly moisture fluxes on both sides of the Sierra Madre Occidental. It also results in an eastward migration of NAM-driven moisture convergence over the western slope of the Mountains. These monsoonal circulation changes lead to a statistically significant increase of precipitation by up to {approx}40% over the eastern slope of the Mountains (Arizona-New Mexico-Texas regions). This study highlights the interaction between dust and the NAM system and motivates further investigation of possible dust feedback on monsoon precipitation under climate change and the megadrought conditions projected for the future.

Zhao, Chun; Liu, Xiaohong; Leung, Lai-Yung R.

2012-04-24T23:59:59.000Z

246

Filamentation instability of current-driven dust ion-acoustic waves in a collisional dusty plasma  

Science Conference Proceedings (OSTI)

A theoretical investigation has been made of the dust ion-acoustic filamentation instability in an unmagnetized current-driven dusty plasma by using the Lorentz transformation formulas. The effect of collision between the charged particles with neutrals and their thermal motion on this instability is considered. Developing the filamentation instability of the current-driven dust ion-acoustic wave allows us to determine the period and the establishment time of the filamentation structure and threshold for instability development.

Niknam, A. R. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran 19839-63113 (Iran, Islamic Republic of); Haghtalab, T.; Khorashadizadeh, S. M. [Physics Department, Birjand University, Birjand 97179-63384 (Iran, Islamic Republic of)

2011-11-15T23:59:59.000Z

247

Anode Dusting from a Potroom Perspective at Nordural And ...  

Science Conference Proceedings (OSTI)

Retrofit of a Combined Breaker Feeder with a Chisel Bath Contact Detection System to Reduce Anode Effect Frequency in a Potroom · Simulating Traffic in a ...

248

Linear trap with three orthogonal quadrupole fields for dust charging experiments  

SciTech Connect

Investigations of charging processes on a single dust grain under controlled conditions in laboratory experiments are the unique way to understand the behavior of dust grains in complex plasma (in space, in laboratory, or in technological applications). An electrodynamic trap is often utilized for both holding a single grain and continuously measuring its charge-to-mass ratio. We propose a modified design of the linear quadrupole trap with the electrodes split into two parts; each of them being supplied by a designated source. The paper presents basic calculations and the results of the trap prototype tests. These tests have confirmed our expectations and have shown that the suggested solution is fully applicable for the dust charging experiments. The uncertainty of determination of the dust grain charge does not exceed 10{sup -3}. The main advantages of the suggested design in comparison with other traps used for dust investigations can be summarized as: The trap (i) is more opened, thus it is suitable for a simultaneous application of the ion and electron beams and UV source; (ii) facilitates investigations of dust grains in a broader range of parameters; and (iii) allows the grain to move along the axis in a controlled way.

Beranek, Martin; Nemecek, Zdenek; Safrankova, Jana; Jerab, Martin; Pavlu, Jiri [Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); Cermak, Ivo [CGC Instruments, Chemnitz (Germany)

2012-11-15T23:59:59.000Z

249

The Spectral Energy Distribution of HH30 IRS: Constraining The Circumstellar Dust Size Distribution  

E-Print Network (OSTI)

We present spectral energy distribution (SED) models for the edge-on classical T Tauri star HH30 IRS that indicate dust grains have grown to larger than 50 microns within its circumstellar disk. The disk geometry and inclination are known from previous modeling of multiwavelength Hubble Space Telescope images and we use the SED to constrain the dust size distribution. Model spectra are shown for different circumstellar dust models: a standard ISM mixture and larger grain models. As compared to ISM grains, the larger dust grain models have a shallower wavelength dependent opacity. Models with the larger dust grains provide a good match to the currently available data, but mid and far-IR observations are required to more tightly constrain the dust size distribution. The accretion luminosity in our models is L_accdistributions that are simple power-law extensions (i.e., no exponential cutoff) yield acceptable fits to the optical/near-IR but too much emission at mm wavelengths and require larger disk masses. Such a simple size distribution would not be expected in an environment such as the disk of HH30 IRS, particularly over such a large range in grain sizes. However, its ability to adequately characterize the grain populations may be determined from more complete observational sampling of the SED in the mid to far-IR.

Kenneth Wood; Michael J. Wolff; J. E. Bjorkman; Barbara Whitney

2001-09-04T23:59:59.000Z

250

Evolution of Thermally Pulsing Asymptotic Giant Branch Stars III. Dust production at supersolar metallicities  

E-Print Network (OSTI)

We extend the formalism presented in our recent calculations of dust ejecta from the Thermally Pulsing Asymptotic Giant Branch (TP-AGB) phase, to the case of super-solar metallicity stars. The TP-AGB evolutionary models are computed with the COLIBRI code. We adopt our preferred scheme for dust growth. For M-giants, we neglect chemisputtering by H$_2$ molecules and, for C-stars we assume a homogeneous growth scheme which is primarily controlled by the carbon over oxygen excess. At super-solar metallicities, dust forms more efficiently and silicates tend to condense significantly closer to the photosphere (r~1.5 R$_*$) - and thus at higher temperatures and densities - than at solar and sub-solar metallicities (r~2-3 R$_*$). In such conditions, the hypothesis of thermal decoupling between gas and dust becomes questionable, while dust heating due to collisions plays an important role. The heating mechanism delays dust condensation to slightly outer regions in the circumstellar envelope. We find that the same mech...

Nanni, Ambra; Marigo, Paola; Girardi, Léo

2013-01-01T23:59:59.000Z

251

Quantifying the Impact of Dust on Heterogeneous Ice Generation in Midlevel Supercooled Stratiform Clouds  

Science Conference Proceedings (OSTI)

Dust aerosols have been regarded as effective ice nuclei (IN), but large uncertainties regarding their efficiencies remain. Here, four years of collocated CALIPSO and CloudSat measurements are used to quantify the impact of dust on heterogeneous ice generation in midlevel supercooled stratiform clouds (MSSCs) over the ‘dust belt’. The results show that the dusty MSSCs have an up to 20% higher mixed-phase cloud occurrence, up to 8 dBZ higher mean maximum Ze (Ze_max), and up to 11.5 g/m2 higher ice water path (IWP) than similar MSSCs under background aerosol conditions. Assuming similar ice growth and fallout history in similar MSSCs, the significant differences in Ze_max between dusty and non-dusty MSSCs reflect ice particle number concentration differences. Therefore, observed Ze_max differences indicate that dust could enhance ice particle concentration in MSSCs by a factor of 2 to 6 at temperatures colder than ?12°C. The enhancements are strongly dependent on the cloud top temperature, large dust particle concentration and chemical compositions. These results imply an important role of dust particles in modifying mixed-phase cloud properties globally.

Zhang, Damao; Wang, Zhien; Heymsfield, Andrew J.; Fan, Jiwen; Liu, Dong; Zhao, Ming

2012-09-26T23:59:59.000Z

252

Brownian Motion of Stars, Dust, and Invisible Matter  

E-Print Network (OSTI)

Treating the motion of a dust particle suspended in a liquid as a random walk, Einstein in 1905 derived an equation describing the diffusion of the particle's probability distribution in configuration space. Fokker and Planck extended this work to describe the velocity distribution of the particles. Their equation and its solutions have been applied to many problems in nature starting with the motion of Brownian particles in a liquid. Chandrasekhar derived the Fokker-Planck equation for stars and showed that long-range gravitational encounters provide a drag force, dynamical friction, which is important in the evolution of star clusters and the formation of galaxies. In certain circumstances, Fokker-Planck evolution also describes the evolution of dark (invisible) matter in the universe. In the early universe, the thermal decoupling of weakly interacting massive particles from the plasma of relativistic leptons and photons is governed by Fokker-Planck evolution. The resulting dissipation imprints a minimum length scale for cosmic density fluctuations. Still later, these density fluctuations produce stochastic gravitational forces on the dark matter as it begins to cluster under gravity. The latter example provides an exact derivation of the Fokker-Planck equation without the usual assumption of Markovian dynamics.

Edmund Bertschinger

2006-08-28T23:59:59.000Z

253

WORLD TRADE CENTER INDOOR DUST TEST AND CLEAN PROGRAM PLAN  

E-Print Network (OSTI)

Background: This Test and Clean Program plan is the result of ongoing efforts to monitor the current environmental conditions for residents and workers impacted by the collapse of the World Trade Center (WTC) towers. In March 2004, EPA convened an expert technical review panel to provide individual guidance and assistance to the Agency in its use of available exposure and health surveillance databases and registries to characterize any remaining exposures and risks, identify unmet public health needs, and to individually recommend steps to further minimize the risks associated with the aftermath of the WTC attack. The WTC Expert Technical Review Panel (WTC Panel) members met periodically in open meetings to interact with EPA and the public about plans to monitor for the presence of WTC dust in indoor environments and to individually suggest additional measures that could be undertaken by EPA and others to evaluate the dispersion of the plume and the geographic extent of environmental impact from the collapse of the WTC towers. The WTC Panel members were charged, in part, with reviewing data from post-cleaning verification sampling to be done by EPA in the residential areas included in EPA Region 2's 2002-3 Indoor Air Residential Assistance Program to verify that recontamination has not

unknown authors

2005-01-01T23:59:59.000Z

254

LOWER MANHATTAN INDOOR DUST TEST AND CLEAN PROGRAM PLAN  

E-Print Network (OSTI)

Background: This Test and Clean Program plan is the result of ongoing efforts to respond to concerns of residents and workers impacted by the collapse of the World Trade Center (WTC) towers. In March 2004, EPA convened an expert technical review panel to provide individual guidance and assistance to the Agency in its use of available exposure and health surveillance databases and registries to characterize any remaining exposures and risks, identify unmet public health needs, and individually recommend steps to further minimize the risks associated with the aftermath of the WTC attack. The WTC Expert Technical Review Panel (WTC Panel) members met periodically in open meetings to interact with EPA and the public about plans to monitor for the presence of WTC dust in indoor environments and to individually suggest additional measures that could be undertaken by EPA and others to evaluate the dispersion of the plume and the geographic extent of environmental impact from the collapse of the WTC towers. The WTC Panel members were charged, in part, with reviewing data from post-cleaning verification sampling to be done by EPA in the residential areas included in EPA Region 2's 2002-2003 Indoor Air Residential Assistance Program to verify that recontamination has not

unknown authors

2006-01-01T23:59:59.000Z

255

Asymptotic analysis of perturbed dust cosmologies to second order  

E-Print Network (OSTI)

Nonlinear perturbations of Friedmann-Lemaitre cosmologies with dust and a positive cosmological constant have recently attracted considerable attention. In this paper our first goal is to compare the evolution of the first and second order perturbations by determining their asymptotic behaviour at late times in ever-expanding models. We show that in the presence of spatial curvature K or a positive cosmological constant, the density perturbation approaches a finite limit both to first and second order, but the rate of approach depends on the model, being power law in the scale factor if the cosmological constant is positive but logarithmic if it is zero and and Kdoes not die away, i.e. it contributes on an equal footing as the growing mode to the asymptotic expression for the density perturbation. On the other hand, the future asymptotic regime of the Einstein-de Sitter universe (for which the cosmological constant and the spatial curvature are both zero) is completely different, as exemplified by the density perturbation which diverges; moreover, the second order perturbation diverges faster than the first order perturbation, which suggests that the Einstein-de Sitter universe is unstable to perturbations, and that the perturbation series do not converge towards the future. We conclude that the presence of spatial curvature or a cosmological constant stabilizes the perturbations. Our second goal is to derive an explicit expression for the second order density perturbation that can be used to study the effects of including a cosmological constant and spatial curvature.

Claes Uggla; John Wainwright

2013-03-19T23:59:59.000Z

256

Electrostatic Transport and Manipulation of Lunar Soil and Dust  

SciTech Connect

Transport and manipulation technologies of lunar soil and dust are under development utilizing the electrostatic force. Transport of particles is realized by an electrostatic conveyer consisting of parallel electrodes. Four-phase traveling electrostatic wave was applied to the electrodes to transport particles upon the conveyer and it was demonstrated that particles were efficiently transported under conditions of low frequency, high voltage, and the application of rectangular wave. Not only linear but also curved and closed transport was demonstrated. Numerical investigation was carried out with a three-dimensional hard-sphere model of the Distinct Element Method to clarify the mechanism of the transport and to predict performances in the lunar environment. This technology is expected to be utilized not only for the transport of bulk soil but also for the cleaning of a solar panel and an optical lens. Another technology is an electrostatic manipulation system to manipulate single particle. A manipulator consisted of two parallel pin electrodes. When voltage was applied between the electrodes, electrophoresis force generated in non-uniform electrostatic field was applied to the particle near the tip of the electrode. The particle was captured by the application of the voltage and released from the manipulator by turning off the voltage. It was possible to manipulate not only insulative but also conductive particles. Three-dimensional electrostatic field calculation was conducted to calculate the electrophoresis force and the Coulomb force.

Kawamoto, Hiroyuki [Department of Applied Mechanics and Aerospace Engineering, Waseda University 3-4-1, Okubo, Shinjuku, Tokyo 169-8555 (Japan)

2008-01-21T23:59:59.000Z

257

Microbial methods of reducing technetium  

DOE Patents (OSTI)

The present invention is directed toward a method for microbial reduction of a technetium compound to form other compounds of value in medical imaging. The technetium compound is combined in a mixture with non-growing microbial cells which contain a technetium-reducing enzyme system, a stabilizing agent and an electron donor in a saline solution under anaerobic conditions. The mixture is substantially free of an inorganic technetium reducing agent and its reduction products. The resulting product is Tc of lower oxidation states, the form of which can be partially controlled by the stabilizing agent. It has been discovered that the microorganisms Shewanella alga, strain Bry and Shewanelia putrifacians, strain CN-32 contain the necessary enzyme systems for technetium reduction and can form both mono nuclear and polynuclear reduced Tc species depending on the stabilizing agent.

Wildung, Raymond E. (Richland, WA); Garland, Thomas R. (Greybull, WY); Gorby, Yuri A. (Richland, WA); Hess, Nancy J. (Benton City, WA); Li, Shu-Mei W. (Richland, WA); Plymale, Andrew E. (Richland, WA)

2001-01-01T23:59:59.000Z

258

Rheological measurements in reduced gravity  

Science Conference Proceedings (OSTI)

Rheology of fluidized beds and settling suspensions were studied experimentally in a series of reduced gravity parabolic flights aboard NASA’s KC?135 aircraft. Silica sands of two different size distributions were fluidized by air. The slurries were made using silica sand and Glycerol solution. The experimental set up incorporated instrumentation to measure the air flow rate

Sayavur I. Bakhtiyarov; Ruel A. Overfelt

1999-01-01T23:59:59.000Z

259

Reduces a processor's energy consumption  

E-Print Network (OSTI)

). Clearly, this is energy inefficient and wasteful of energy. 2 More precisely, the faster that a processor decide that energy is being wasted and will decrease the frequency/voltage level. Translation: LowerReduces a processor's energy consumption by up to 70% Diminishes greenhouse gas emissions Improves

260

METHOD OF REDUCING PLUTONIUM COMPOUNDS  

DOE Patents (OSTI)

A method is described for reducing plutonium compounds in aqueous solution from a higher to a lower valence state. This reduction of valence is achieved by treating the aqueous solution of higher valence plutonium compounds with hydrogen in contact with an activated platinum catalyst.

Johns, I.B.

1958-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
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261

DUST SPECTRAL ENERGY DISTRIBUTIONS IN THE ERA OF HERSCHEL AND PLANCK: A HIERARCHICAL BAYESIAN-FITTING TECHNIQUE  

SciTech Connect

We present a hierarchical Bayesian method for fitting infrared spectral energy distributions (SEDs) of dust emission to observed fluxes. Under the standard assumption of optically thin single temperature (T) sources, the dust SED as represented by a power-law-modified blackbody is subject to a strong degeneracy between T and the spectral index {beta}. The traditional non-hierarchical approaches, typically based on {chi}{sup 2} minimization, are severely limited by this degeneracy, as it produces an artificial anti-correlation between T and {beta} even with modest levels of observational noise. The hierarchical Bayesian method rigorously and self-consistently treats measurement uncertainties, including calibration and noise, resulting in more precise SED fits. As a result, the Bayesian fits do not produce any spurious anti-correlations between the SED parameters due to measurement uncertainty. We demonstrate that the Bayesian method is substantially more accurate than the {chi}{sup 2} fit in recovering the SED parameters, as well as the correlations between them. As an illustration, we apply our method to Herschel and submillimeter ground-based observations of the star-forming Bok globule CB244. This source is a small, nearby molecular cloud containing a single low-mass protostar and a starless core. We find that T and {beta} are weakly positively correlated-in contradiction with the {chi}{sup 2} fits, which indicate a T-{beta} anti-correlation from the same data set. Additionally, in comparison to the {chi}{sup 2} fits the Bayesian SED parameter estimates exhibit a reduced range in values.

Kelly, Brandon C.; Goodman, Alyssa A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Shetty, Rahul [Zentrum fuer Astronomie der Universitaet Heidelberg, Institut fuer Theoretische Astrophysik, Albert-Ueberle-Str. 2, 69120 Heidelberg (Germany); Stutz, Amelia M.; Launhardt, Ralf [Max Planck Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg (Germany); Kauffmann, Jens [NASA JPL, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

2012-06-10T23:59:59.000Z

262

FRAGMENTATION AND EVOLUTION OF MOLECULAR CLOUDS. III. THE EFFECT OF DUST AND GAS ENERGETICS  

SciTech Connect

Dust and gas energetics are incorporated into a cluster-scale simulation of star formation in order to study the effect of heating and cooling on the star formation process. We build on our previous work by calculating separately the dust and gas temperatures. The dust temperature is set by radiative equilibrium between heating by embedded stars and radiation from dust. The gas temperature is determined using an energy-rate balance algorithm which includes molecular cooling, dust-gas collisional energy transfer, and cosmic-ray ionization. The fragmentation proceeds roughly similarly to simulations in which the gas temperature is set to the dust temperature, but there are differences. The structure of regions around sink particles has properties similar to those of Class 0 objects, but the infall speeds and mass accretion rates are, on average, higher than those seen for regions forming only low-mass stars. The gas and dust temperature have complex distributions not well modeled by approximations that ignore the detailed thermal physics. There is no simple relationship between density and kinetic temperature. In particular, high-density regions have a large range of temperatures, determined by their location relative to heating sources. The total luminosity underestimates the star formation rate at these early stages, before ionizing sources are included, by an order of magnitude. As predicted in our previous work, a larger number of intermediate-mass objects form when improved thermal physics is included, but the resulting initial mass function (IMF) still has too few low-mass stars. However, if we consider recent evidence on core-to-star efficiencies, the match to the IMF is improved.

Martel, Hugo [Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, QC, G1V 0A6 (Canada); Urban, Andrea [Sapling Learning, Inc., 2815 Exposition Blvd, Austin, TX 78703 (United States); Evans, Neal J. II [Department of Astronomy, University of Texas, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States)

2012-09-20T23:59:59.000Z

263

Unconventional Groundwater System Proves Effective in Reducing...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Unconventional Groundwater System Proves Effective in Reducing Contamination at West Valley Demonstration Project Unconventional Groundwater System Proves Effective in Reducing...

264

Application of Synchrotron Microprobe Methods to Solid-Phase Speciation of Metals and Metalloids in House Dust  

Science Conference Proceedings (OSTI)

Determination of the source and form of metals in house dust is important to those working to understand human and particularly childhood exposure to metals in residential environments. We report the development of a synchrotron microprobe technique for characterization of multiple metal hosts in house dust. We have applied X-ray fluorescence for chemical characterization and X-ray diffraction for crystal structure identification using microfocused synchrotron X-rays at a less than 10 {micro}m spot size. The technique has been evaluated by application to archived house dust samples containing elevated concentrations of Pb, Zn, and Ba in bedroom dust, and Pb and As in living room dust. The technique was also applied to a sample of soil from the corresponding garden to identify linkages between indoor and outdoor sources of metals. Paint pigments including white lead (hydrocerussite) and lithopone (wurtzite and barite) are the primary source of Pb, Zn, and Ba in bedroom dust, probably related to renovation activity in the home at the time of sampling. The much lower Pb content in the living room dust shows a relationship to the exterior soil and no specific evidence of Pb and Zn from the bedroom paint pigments. The technique was also successful at confirming the presence of chromated copper arsenate treated wood as a source of As in the living room dust. The results of the study have confirmed the utility of this approach in identifying specific metal forms within the dust.

S Walker; H Jamieson; P Rasmussen

2011-12-31T23:59:59.000Z

265

FORMING PLANETESIMALS BY GRAVITATIONAL INSTABILITY. II. HOW DUST SETTLES TO ITS MARGINALLY STABLE STATE  

SciTech Connect

Dust at the midplane of a circumstellar disk can become gravitationally unstable and fragment into planetesimals if the local dust-to-gas ratio {mu}{sub 0} {identical_to} {rho}{sub d}/{rho}{sub g} is sufficiently high. We simulate how dust settles in passive disks and ask how high {mu}{sub 0} can become. We implement a hybrid scheme that alternates between a one-dimensional code to settle dust and a three-dimensional shearing box code to test for dynamical stability. This scheme allows us to explore the behavior of small particles having short but non-zero stopping times in gas: 0 < t{sub stop}<< the orbital period. The streaming instability is thereby filtered out. Dust settles until Kelvin-Helmholtz-type instabilities at the top and bottom faces of the dust layer threaten to overturn the entire layer. In this state of marginal stability, {mu}{sub 0} = 2.9 for a disk whose bulk (height-integrated) metallicity {Sigma}{sub d}/{Sigma}{sub g} is solar-thus {mu}{sub 0} increases by more than two orders of magnitude from its well-mixed initial value of {mu}{sub 0,init} = {Sigma}{sub d}/{Sigma}{sub g} = 0.015. For a disk whose bulk metallicity is 4x solar ({mu}{sub 0,init} = {Sigma}{sub d}/{Sigma}{sub g} = 0.06), the marginally stable state has {mu}{sub 0} = 26.4. These maximum values of {mu}{sub 0}, which depend on the background radial pressure gradient, are so large that gravitational instability of small particles is viable in disks whose bulk metallicities are just a few ({approx}<4) times solar. Our result supports earlier studies that assumed that dust settles until the Richardson number Ri is spatially constant. Our simulations are free of this assumption but provide evidence for it within the boundaries of the dust layer, with the proviso that Ri increases with {Sigma}{sub d}/{Sigma}{sub g} in the same way that we found in Paper I. Because increasing the dust content decreases the vertical shear and increases stability, the midplane {mu}{sub 0} increases with {Sigma}{sub d}/{Sigma}{sub g} in a faster than linear way, so fast that modest enhancements in {Sigma}{sub d}/{Sigma}{sub g} can spawn planetesimals directly from small particles.

Lee, Aaron T.; Chiang, Eugene [Department of Astronomy, University of California Berkeley, Berkeley, CA 94720 (United States); Asay-Davis, Xylar [Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Barranco, Joseph, E-mail: a.t.lee@berkeley.ed [Department of Physics and Astronomy, San Francisco State University, San Francisco, CA 94132 (United States)

2010-12-20T23:59:59.000Z

266

PAHs underfoot: contaminated dust from coal-tar sealcoated pavement is widespread in the United States  

Science Conference Proceedings (OSTI)

We reported in 2005 that runoff from parking lots treated with coal-tar-based sealcoat was a major source of polycyclic aromatic hydrocarbons (PAHs) to streams in Austin, Texas. Here we present new data from nine U.S. cities that show nationwide patterns in concentrations of {Sigma}PAHs associated with sealcoat. Dust was swept from parking lots in six cities in the central and eastern U.S., where coal-tar-based sealcoat dominates use, and three cities in the western U.S., where asphalt-based sealcoat dominates use. For six central and eastern cities, median SPAH concentrations in dust from sealcoated and unsealcoated pavement are 2200 and 27 mg/kg, respectively. For three western cities, median SPAH concentrations in dust from sealcoated and unsealcoated pavement are similar and very low (2.1 and 0.8 mg/kg, respectively). Lakes in the central and eastern cities where pavement was sampled have bottom sediments with higher PAH concentrations than do those in the western cities relative to degree of urbanization. Bottom-sediment PAH assemblages are similar to those of sealcoated pavement dust regionally, implicating coal-tar-based sealcoat as a PAH source to the central and eastern lakes. Concentrations of benzo(a)pyrene in dust from coal-tar sealcoated pavement and adjacent soils greatly exceed generic soil screening levels, suggesting that research on human-health risk is warranted. 30 refs., 4 figs., 2 tabs.

Peter C. Van Metre; Barbara J. Mahler; Jennifer T. Wilson [U.S. Geological Survey, Austin, TX (USA)

2009-01-15T23:59:59.000Z

267

Seize Opportunities to Reduce Cost  

NLE Websites -- All DOE Office Websites (Extended Search)

Specify for maximum energy savings Specify for maximum energy savings Windows must meet local energy code requirements. For even higher energy performance, consider ENERGY STAR windows, which are recommended for low-rise dwellings and are often suitable for mid-rise dwellings as well. For window and storm window options with superior performance in cold climates, check out the U.S. Department of Energy's highly insulating windows purchasing program (see next page). Seize Opportunities to Reduce Cost Government or utility incentives and financing may be available for energy efficiency in low-income housing. Check www.dsireusa.org for up-to-date information on incentive

268

Diffusion Dynamics of Charged Dust Particles in Capacitively Coupled RF Discharge System  

SciTech Connect

Dusty plasma is loosely defined as electron-ion plasma with additional charged components of micron-sized dust particles. In this study, we developed a particle diagnostic technique based on light scattering and particle tracking velocimetry to investigate the dynamics of micron-sized titanium oxide particles in Argon gas capacitively coupled rf-discharge. The particle trajectories are constructed from sequence of image frames and treated as sample paths of charged Brownian motion. At specific sets of plasma parameters, disordered liquid-like dust particle configuration are observed. Mean-square-displacement of the particle trajectories are determined to characterize the transport dynamics. We showed that the dust particles in disordered liquid phase exhibit anomalous diffusion with different scaling exponents for short and large time scales, indicating the presence of slow and fast modes which can be related to caging effect and dispersive transport, respectively.

Chew, W. X.; Muniandy, S. V.; Wong, C. S.; Yap, S. L.; Tan, K. S. [Plasma Research Laboratory, Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2011-03-30T23:59:59.000Z

269

Evaluation of an Electrostatic Dust Removal System with Potential Application in Next-Step Fusion Devices  

SciTech Connect

The ability to manage inventories of carbon, tritium, and high-Z elements in fusion plasmas depends on means for effective dust removal. A dust conveyor, based on a moving electrostatic potential well, was tested with particles of tungsten, carbon, glass and sand. A digital microscope imaged a representative portion of the conveyor, and dust particle size and volume distributions were derived before and after operation. About 10 mm3 volume of carbon and tungsten particles were moved in under 5 seconds. The highest driving amplitude tested of 3 kV was the most effective. The optimal driving frequency was 210 Hz (maximum tested) for tungsten particles, decreasing to below 60 Hz for the larger sand particles. Measurements of particle size and volume distributions after 10 and 100 cycles show the breaking apart of agglomerated carbon, and the change in particle distribution over short timescales (<1 s).

F.Q.L. Friesen, B. John, C.H. Skinner, A.L. Roquemore and C.I. Calle

2011-01-20T23:59:59.000Z

270

Evaluation of an electrostatic dust removal system with potential application in next-step fusion devices  

Science Conference Proceedings (OSTI)

The ability to manage inventories of carbon, tritium, and high-Z elements in fusion plasmas depends on means for effective dust removal. A dust conveyor, based on a moving electrostatic potential well, was tested with particles of tungsten, carbon, glass, and sand. A digital microscope imaged a representative portion of the conveyor, and dust particle size and volume distributions were derived before and after operation. About 10 mm{sup 3} volume of carbon and tungsten particles were moved in under 5 s. The highest driving amplitude tested of 3 kV was the most effective. The optimal driving frequency was 210 Hz (maximum tested) for tungsten particles, decreasing to below 60 Hz for the larger sand particles. Measurements of particle size and volume distributions after 10 and 100 cycles show the breaking apart of agglomerated carbon and the change in particle distribution over short timescales (<1 s).

Friesen, F. Q. L. [Grinnell College, 1115 8th Avenue, Grinnell, Iowa 50112-1616 (United States); John, B. [Swarthmore College, 500 College Ave., Swarthmore, Pennsylvania 19081 (United States); Skinner, C. H.; Roquemore, A. L. [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 (United States); Calle, C. I. [NASA Electrostatics and Surface Physics Laboratory, Kennedy Space Center, Florida 32899 (United States)

2011-05-15T23:59:59.000Z

271

Evidence for dust emission in the Warm Ionised Medium using WHAM data  

E-Print Network (OSTI)

We have used the WHAM H_alpha survey and Leiden/Dwingeloo HI data to decompose the Far-infrared emission (from 100 to 1000 micron) at high Galactic latitude into components associated with the Warm Ionised Medium (WIM) and the Warm Neutral Medium (WNM). This decomposition is possible for the first time thanks to preliminary WHAM data that cover a significant fraction of the sky (about 10%). We confirm the first detection of dust emission from the WIM (Lagache et al. 1999) and show that the WIM dust temperature and emissivity are very similar to those in the WNM. The analysis suggests moreover that about 25% of the far-IR dust emission at high galactic latitude is uncorrelated with the HI gas. The decomposition again reveals a Cosmic Far-Infrared Background (CFIRB) which is determined for the first time from 100 to 1000 micron using two independant gas tracers.

Lagache, G; Reynolds, R J; Tufte, S L

1999-01-01T23:59:59.000Z

272

Evidence for dust emission in the Warm Ionised Medium using WHAM data  

E-Print Network (OSTI)

We have used the WHAM H_alpha survey and Leiden/Dwingeloo HI data to decompose the Far-infrared emission (from 100 to 1000 micron) at high Galactic latitude into components associated with the Warm Ionised Medium (WIM) and the Warm Neutral Medium (WNM). This decomposition is possible for the first time thanks to preliminary WHAM data that cover a significant fraction of the sky (about 10%). We confirm the first detection of dust emission from the WIM (Lagache et al. 1999) and show that the WIM dust temperature and emissivity are very similar to those in the WNM. The analysis suggests moreover that about 25% of the far-IR dust emission at high galactic latitude is uncorrelated with the HI gas. The decomposition again reveals a Cosmic Far-Infrared Background (CFIRB) which is determined for the first time from 100 to 1000 micron using two independant gas tracers.

G. Lagache; L. M. Haffner; R. J. Reynolds; S. L. Tufte

1999-11-18T23:59:59.000Z

273

Observations of the impact of a major Saharan dust storm on the atmospheric radiation balance  

SciTech Connect

Saharan dust storms transport large quantities of material across the African continent and beyond, causing widespread disruption and hazards to health. The dust may be deposited into the Atlantic Ocean, where it provides an important source of nutrients1, and may be carried as far as the West Indies. Such events may also influence the growth of Atlantic tropical cyclones. Satellite observations have enabled estimates to be made of the effect of the dust on the radiation budget seen from space, but only limited in situ observations have hitherto been made at the surface. Here we present the first simultaneous and continuous observations of the effect of a major dust storm in March 2006 on the radiation budget both at the top of the atmosphere (TOA) and at the surface. We combine data from the Geostationary Earth Radiation Budget (GERB) broadband radiometer and the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) on the Meteosat-8 weather satellite with remote sensing and in situ measurements from a new Mobile Facility located in Niamey, Niger (13{sup o} 29'N, 2{sup o} 10'E), operated by the US Atmospheric Radiation Measurement (ARM) program. We show that the dust produced major perturbations to the radiation budget seen from space and from the surface. By combining the two datasets, we estimate the impact on the radiation budget of the atmosphere itself. Using independent data from the Mobile Facility, we derive the optical properties of the dust and input these and other information into radiation codes to simulate the radiative fluxes. Comparisons with the observed fluxes provides a stringent test of the ability of the codes to represent the radiative properties of this important component of the global aerosol burden.

Slingo, A.; Ackerman, Thomas P.; Allan, R. P.; Kassianov, Evgueni I.; McFarlane, Sally A.; Robinson, G. J.; Barnard, James C.; Miller, Mark; Harries, J. E.; Russell, J. E.; Dewitte, S.

2006-12-01T23:59:59.000Z

274

ICE AND DUST IN THE PRESTELLAR DARK CLOUD LYNDS 183: PREPLANETARY MATTER AT THE LOWEST TEMPERATURES  

Science Conference Proceedings (OSTI)

Dust grains are nucleation centers and catalysts for the growth of icy mantles in quiescent interstellar clouds, the products of which may accumulate into preplanetary matter when new stars and solar systems form within the clouds. In this paper, we present the first spectroscopic detections of silicate dust and the molecular ices H{sub 2}O, CO, and CO{sub 2} in the vicinity of the prestellar core L183 (L134N). An infrared photometric survey of the cloud was used to identify reddened background stars, and we present spectra covering solid-state absorption features in the wavelength range 2-20 {mu}m for nine of them. The mean composition of the ices in the best-studied line of sight (toward J15542044-0254073) is H{sub 2}O:CO:CO{sub 2} Almost-Equal-To 100:40:24. The ices are amorphous in structure, indicating that they have been maintained at low temperature ({approx}ice column density N(H{sub 2}O) correlates with reddening by dust, exhibiting a threshold effect that corresponds to the transition from unmantled grains in the outer layers of the cloud to ice-mantled grains within, analogous to that observed in other dark clouds. A comparison of results for L183 and the Taurus and IC 5146 dark clouds suggests common behavior, with mantles first appearing in each case at a dust column corresponding to a peak optical depth {tau}{sub 9.7} = 0.15 {+-} 0.03 in the silicate feature. Our results support a previous conclusion that the color excess E{sub J-K} does not obey a simple linear correlation with the total dust column in lines of sight that intercept dense clouds. The most likely explanation is a systematic change in the optical properties of the dust as the density increases.

Whittet, D. C. B.; Poteet, C. A.; Bajaj, V. M.; Horne, D. [Department of Physics, Applied Physics and Astronomy and New York Center for Astrobiology, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States); Chiar, J. E. [SETI Institute, Carl Sagan Center, 189 Bernardo Avenue, Mountain View, CA 94043 (United States); Pagani, L. [LERMA, UMR 8112 du CNRS, Observatoire de Paris, 61 Av. de l'Observatoire, F-75014 Paris (France); Shenoy, S. S. [SOFIA Science Center, NASA Ames Research Center, MS 232-12, Moffett Field, CA 94035 (United States); Adamson, A. J. [Gemini Observatory, Southern Operations Center, Casilla 603, La Serena (Chile)

2013-09-10T23:59:59.000Z

275

The effect of stellar evolution on SiC dust grain sizes  

E-Print Network (OSTI)

Stars on the asymptotic giant branch (AGB) produce dust in their circumstellar shells. The nature of the dust-forming environment is influenced by the evolution of the stars, in terms of both chemistry and density, leading to an evolution in the nature of the dust that is produced. Carbon-rich AGB stars are known to produce silicon carbide (SiC). Furthermore, observations of the ~11um SiC feature show that the spectral features change in a sequence that correlates with stellar evolution. We present new infrared spectra of amorphous SiC and show that the ~9um feature seen in both emission and absorption, and correlated with trends in the ~11um feature, may be due to either amorphous SiC or to nano-crystalline diamond with a high proportion of Si substituting for C. Furthermore, we identify SiC absorption in three ISO spectra of extreme carbon stars, in addition to the four presented by Speck et al. (1997). An accurate description of the sequence in the IR spectra of carbon stars requires accounting for both SiC emission and absorption features. This level of detail is needed to infer the role of dust in evolution of carbon stars. Previous attempts to find a sequence in the infrared spectra of carbon stars considered SiC emission features, while neglecting SiC absorption features, leading to an interpretation of the sequence inadequately describes the role of dust. We show that the evolutionary sequence in carbon star spectra is consistent with a grain size evolution, such that dust grains get progressively smaller as the star evolves. The evolution of the grain sizes provides a natural explanation for the shift of the ~11um SiC feature in emission and in absorption. Further evidence for this scenario is seen in both post-AGB star spectra and in meteoritic studies of presolar grains.

Angela Speck; Grant Thompson; Anne Hofmeister

2005-08-04T23:59:59.000Z

276

FINAL STATUS OF GENERAL ENGINEERING LABORATORY AIR FLOW AND DUST TEST PROGRAM. PART I. PART II  

SciTech Connect

A full scale 15 deg sector of the P122 reactor configuration was constructed. The model was complete with respect to all internal cooling air passages, and reflectors, thermal shielding, and island reflector. The contract was terminated before any test data could be obtained. Investigation of the effect of atmospheric dust on performance of reactor systems using wire screen matrix fuel elements is reported. The interim conclusion is that dust would not limit aircraft performance or life. Work proposed but not completed is outlined. Appendices contain previously unpublished reports. (auth)

Venneman, W.F.; Lawrence, R.L.; Ryan, P.T.

1961-05-25T23:59:59.000Z

277

Dust-acoustic filamentation of a current-driven dusty plasma  

Science Conference Proceedings (OSTI)

The thermal motion effect of charged particles in the filamentation of a current-driven dusty plasma in the dust-acoustic frequency region is investigated by using the Lorentz transformed conductivity of the dusty plasma components and the total dielectric permittivity tensor of the dusty plasma in the laboratory frame. Obtaining the dispersion relation for dust-acoustic waves and considering the filamentation instability, the establishment time of the filamentation structure and the instability development threshold are derived. Moreover, it is shown that the current layer divides into separate current filaments.

Khorashadizadeh, S. M.; Haghtalab, T. [Physics Department, Birjand University, Birjand, 97179-63384 (Iran, Islamic Republic of); Niknam, A. R. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran, 19839-63113 (Iran, Islamic Republic of)

2011-06-15T23:59:59.000Z

278

Dense Star-forming Gas and Dust in the Magellanic Clouds  

E-Print Network (OSTI)

The early stages of star formation are closely related to the ambient conditions in the interstellar medium. Important questions such as dust abundance, size distribution, temperature distribution, fraction of molecular gas, fraction of dense gas, gas surface density and total amount of gas and dust require separation of metallicity and radiation effects. The Magellanic Clouds provide an ideal laboratory to carry out such studies. They are prominent targets for space observatories (Spitzer, Herschel), but an important role remains for large groundbased facilities, such as a 25 m class sub-millimeter telescope on Dome C.

Israel, F P

2009-01-01T23:59:59.000Z

279

Experimental and numerical analysis of dust resuspension for supporting chemical and radiological risk assessment in a nuclear fusion device  

Science Conference Proceedings (OSTI)

A recognized safety issue for future fusion reactors fueled with deuterium and tritium is the generation of sizeable quantities of dust. Several mechanisms like plasma disruptions, Edge Localized Modes (ELM) and Vertical Displacement Events (VDE) resulting ... Keywords: CFD, LOVA, dust mobilization, nuclear fusion safety

P. Gaudio; A. Malizia; I. Lupelli

2010-11-01T23:59:59.000Z

280

Lead Speciation in Indoor Dust: A Case Study to Assess Old Paint Contribution in a Canadian Urban House  

SciTech Connect

Residents in older homes may experience increased lead (Pb) exposures due to release of lead from interior paints manufactured in past decades, especially pre-1960s. The objective of the study was to determine the speciation of Pb in settled dust from an urban home built during WWII. X-ray absorption near-edge structure (XANES) and micro-X-ray diffraction (XRD) analyses were performed on samples of paint (380-2,920 mg Pb kg{sup -1}) and dust (200-1,000 mg Pb kg{sup -1}) collected prior to renovation. All dust samples exhibited a Pb XANES signature similar to that of Pb found in paint. Bulk XANES and micro-XRD identified Pb species commonly found as white paint pigments (Pb oxide, Pb sulfate, and Pb carbonate) as well as rutile, a titanium-based pigment, in the <150 m house dust samples. In the dust fraction <36 {mu}m, half of the Pb was associated with the Fe-oxyhydroxides, suggesting additional contribution of outdoor sources to Pb in the finer dust. These results confirm that old paints still contribute to Pb in the settled dust for this 65-year-old home. The Pb speciation also provided a clearer understanding of the Pb bioaccessibility: Pb carbonate > Pb oxide > Pb sulfate. This study underscores the importance of taking precautions to minimize exposures to Pb in house dust, especially in homes where old paint is exposed due to renovations or deterioration of painted surfaces.

S Beauchemin; L MacLean; P Rasmussen

2011-12-31T23:59:59.000Z

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Lead speciation in indoor dust: a case study to assess old paint contribution in a Canadian urban house  

SciTech Connect

Residents in older homes may experience increased lead (Pb) exposures due to release of lead from interior paints manufactured in past decades, especially pre-1960s. The objective of the study was to determine the speciation of Pb in settled dust from an urban home built during WWII. X-ray absorption near-edge structure (XANES) and micro-X-ray diffraction (XRD) analyses were performed on samples of paint (380-2,920 mg Pb kg{sup -1}) and dust (200-1,000 mg Pb kg{sup -1}) collected prior to renovation. All dust samples exhibited a Pb XANES signature similar to that of Pb found in paint. Bulk XANES and micro-XRD identified Pb species commonly found as white paint pigments (Pb oxide, Pb sulfate, and Pb carbonate) as well as rutile, a titanium-based pigment, in the <150 {micro}m house dust samples. In the dust fraction <36 {micro}m, half of the Pb was associated with the Fe-oxyhydroxides, suggesting additional contribution of outdoor sources to Pb in the finer dust. These results confirm that old paints still contribute to Pb in the settled dust for this 65-year-old home. The Pb speciation also provided a clearer understanding of the Pb bioaccessibility: Pb carbonate > Pb oxide > Pb sulfate. This study underscores the importance of taking precautions to minimize exposures to Pb in house dust, especially in homes where old paint is exposed due to renovations or deterioration of painted surfaces.

Beauchemin, Suzanne; MacLean, Lachlan C.W.; Rasmussen, Pat E. (Health Canada); (NRC)

2012-10-23T23:59:59.000Z

282

Spitzer Infrared Spectrograph Observations of Magellanic Cloud Planetary Nebulae: the nature of dust in low metallicity circumstellar ejecta  

E-Print Network (OSTI)

We present 5 - 40 micron spectroscopy of 41 planetary nebulae (PNe) in the Magellanic Clouds, observed with the Infrared Spectrograph on board the Spitzer Space Telescope. The spectra show the presence of a combination of nebular emission lines and solid-state features from dust, superimposed on the thermal IR continuum. By analyzing the 25 LMC and 16 SMC PNe in our sample we found that the IR spectra of 14 LMC and 4 SMC PNe are dominated by nebular emission lines, while the other spectra show solid-state features. We observed that the solid-state features are compatible with carbon-rich dust grains (SiC, polycyclic aromatic hydrocarbons (PAHs), etc.) in most cases, except in three PNe showing oxygen-rich dust features. The frequency of carbonaceous dust features is generally higher in LMC than in SMC PNe. The spectral analysis allowed the correlations of the dust characteristics with the gas composition and morphology, and the properties of the central stars. We found that: 1) all PNe with carbonaceous dust features have C/O>1, none of these being bipolar or otherwise highly asymmetric; 2) all PNe with oxygen-rich dust features have C/Oproduction efficiency depends on metallicity, with low metallicity environments not favoring dust production.

L. Stanghellini; P. Garcia-Lario; D. A. Garcia-Hernandez; J. V. Perea-Calderon; J. E. Davies; A. Manchado; E. Villaver; R. A. Shaw

2007-09-04T23:59:59.000Z

283

Reducing the Federal Energy Bill  

NLE Websites -- All DOE Office Websites (Extended Search)

1 1 Reducing the Federal Energy Bill Berkeley Lab's Work with the Federal Energy Management Program It costs billions of dollars and uses more energy than any other entity in the United States. What is it? Answer: the Federal government. In fiscal year 1995, the Federal government spent $8 billion on a net energy consumption of 1.15 quadrillion BTUs. While that may be a lot of energy in absolute terms, the numbers have been improving for years. Compared with fiscal year 1985, the 1995 energy-use figure is down by 22.5%, and the costs are down $2.5 billion. The decline is explained in part by the activities of FEMP (the Federal Energy Management Program) and the efforts of energy-efficiency experts at national laboratories, such as those at Berkeley Lab's Environmental Energy

284

Quench cooling under reduced gravity  

E-Print Network (OSTI)

We report the quench cooling experiments performed with liquid O2 under different levels of gravity simulated with the magnetic gravity compensation. A copper disk is quenched from 270K to 90K. It is found that the cooling time in microgravity is very long in comparison with any other gravity level. This phenomenon is explained by the isolation effect of the gas surrounding the disk. The liquid subcooling is shown to drastically improuve the heat exchange thus reducing the cooling time (about 20 times). The effect of subcooling on the heat transfer is analyzed at different gravity levels. It is shown that such type of experiments cannot be used for the analysis of the critical heat flux (CHF) of the boiling crisis. The minimum heat flux (MHF) of boiling is analyzed instead.

Chatain, D; Nikolayev, V S; Beysens, D

2013-01-01T23:59:59.000Z

285

Reduced vibration motor winding arrangement  

DOE Patents (OSTI)

An individual phase winding arrangement having a sixty electrical degree phase belt width for use with a three phase motor armature includes a delta connected phase winding portion and a wye connected phase winding portion. Both the delta and wye connected phase winding portions have a thirty electrical degree phase belt width. The delta and wye connected phase winding portions are each formed from a preselected number of individual coils each formed, in turn, from an unequal number of electrical conductor turns in the approximate ratio of {radical}3. The individual coils of the delta and wye connected phase winding portions may either be connected in series or parallel. This arrangement provides an armature winding for a three phase motor which retains the benefits of the widely known and utilized thirty degree phase belt concept, including improved mmf waveform and fundamental distribution factor, with consequent reduced vibrations and improved efficiency. 4 figs.

Slavik, C.J.; Rhudy, R.G.; Bushman, R.E.

1997-11-11T23:59:59.000Z

286

U.K. HiGEM: Simulations of Desert Dust and Biomass Burning Aerosols with a High-Resolution Atmospheric GCM  

Science Conference Proceedings (OSTI)

The atmospheric component of the United Kingdom’s new High-resolution Global Environmental Model (HiGEM) has been run with interactive aerosol schemes that include biomass burning and mineral dust. Dust emission, transport, and deposition are ...

M. J. Woodage; A. Slingo; S. Woodward; R. E. Comer

2010-04-01T23:59:59.000Z

287

Charging and de-charging of dust particles in bulk region of a radio frequency discharge plasma  

SciTech Connect

An analysis to investigate the effect of the dust particle size and density on the floating potential of the dust particles of uniform radius and other plasma parameters in the bulk region plasma of a RF-discharge in collisionless/collisional regime has been presented herein. For this purpose, the average charge theory based on charge balance on dust and number balance of plasma constituents has been utilized; a derivation for the accretion rate of electrons corresponding to a drifting Maxwellian energy distribution in the presence of an oscillatory RF field has been given and the resulting expression has been used to determine the floating potential of the dust grains. Further, the de-charging of the dust grains after switching off the RF field has also been discussed.

Mishra, S. K. [Institute for Plasma Research, Gandhinagar 382428 (India); Misra, Shikha; Sodha, M. S. [Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi 110016 (India)

2013-03-15T23:59:59.000Z

288

Notes from December 6, 2012, DOE Fugitive Emissions Working Group...  

NLE Websites -- All DOE Office Websites (Extended Search)

dropped to less than 4% by 2010. Final Review of Paper on SF 6 Byproduct Safety (Jane Powers, HS-21) Jane Powers described the two main changes that were made to the SF 6...

289

Notes from November 15, 2011 DOE Fugitive Emissions Working Group...  

NLE Websites -- All DOE Office Websites (Extended Search)

Silverman, FEWG Chair, and Contributions from the field) The 2011 DOE Strategic Sustainability Performance Plan (SSPP) has been released and is available on the SPO's website...

290

Fabrication of Lamellar Ceramic Recuperator Using a Fugitive ...  

Science Conference Proceedings (OSTI)

... of this study is to demonstrate a CERAMIC recuperator based on toughened mullite, which is a key component of a high efficiency, all-ceramic micro-turbine.

291

Chasing Down Fugitive Emissions | Princeton Plasma Physics Lab  

NLE Websites -- All DOE Office Websites (Extended Search)

April 25, 2011 Tweet Widget Facebook Like Google Plus One PPPL's Tim Stevenson takes inventory of the SF6 levels at a power supply tank for NSTX. (Photo by Elle...

292

Prime movers reduce energy costs  

SciTech Connect

Many industrial plants have found that reciprocating engines used to power generator sets and chiller systems are effective in reducing energy costs as part of a load management strategy, while meeting other plant energy needs. As the trend towards high electric utility costs continues, familiarity with basic analyses used to determine the economic viability of engine-driven systems is essential. A basic method to determine the economic viability of genset or chiller systems is to review the supplying utility`s rate structure, determine approximate costs to install and operate an engine-driven system, and calculate a simple equipment payback period. If the initial analysis shows that significant savings are possible and a quick payback is likely, a thorough analysis should be conducted to analyze a plant`s actual electric load profile. A load profile analysis takes into consideration average loads, peak loads, and peak duration. A detailed study should cover myriad considerations, including local air quality regulations and permitting, space availability, auxiliary system components, and financing options. A basic analysis takes relatively little time and can rule out the need for a detailed study.

Swanson, J.E. [Caterpillar, Inc., Mossville, IL (United States)

1996-01-01T23:59:59.000Z

293

Reduced vibration motor winding arrangement  

DOE Patents (OSTI)

The present invention relates generally to an electric motor winding and, more particularly, to a three phase motor armature winding arrangement designed to reduce motor vibration and improve efficiency. An individual phase winding arrangement having a sixty electrical degree phase belt width for use with a three phase motor armature includes a delta connected phase winding portion and a wye connected phase winding portion. Both the delta and wye connected phase winding portions have a thirty electrical degree phase belt width. The delta and wye connected phase winding portions are each formed from a preselected number of individual coils each formed, in turn, from an unequal number of electrical conductor turns in the approximate ratio of {radical}3. The individual coils of the delta and wye connected phase winding portions may either be connected in series or parallel. This arrangement provides an armature winding for a three phase motor which retains the benefits of the widely known and utilized thirty degree phase belt concept, including improved mmf waveform and fundamental distribution factor.

Slavik, C.J.; Rhudy, R.G.; Bushman, R.E.

1995-12-31T23:59:59.000Z

294

Variations of the Dust Storm in China and its Climatic Control  

Science Conference Proceedings (OSTI)

In previous studies, limited meteorological observations were used to investigate the temporal–spatial changes of dust storms in China. Here, the authors use the daily 850-hPa geopotential height of NCEP–NCAR reanalysis for 1948–99 to examine the ...

Weihong Qian; Lingshen Quan; Shaoyin Shi

2002-05-01T23:59:59.000Z

295

Features of coal dust dynamics at action of differently oriented forces in granular filtering medium  

E-Print Network (OSTI)

The process of the coal dust particles transportation and structurization in the experimental horizontal model of air filter with the cylindrical coal adsorbent granules as in the iodine air filter at the nuclear power plant is researched. In the investigated case the vector of carrying away force of air flow and the vector of gravitation force are mutually perpendicular, and the scattering of the dust particles on the granules occurs in the normal directions. It is found that the phenomenon of non controlled spontaneous sharp increase of aerodynamic resistance in the iodine air filter under the big integral volumes of filtered air and the big masses of introduced coal dust particles is not observed at the described experimental conditions in distinction from the case of the parallel orientation of this forces as in the vertical iodine air filters at the nuclear power plant. The quantitative measurements of the main parameters of the process of the dust masses transportation and structurization are made on a developed experimental model of the iodine air filter with the cylindrical coal adsorbent granules.

I. M. Neklyudov; L. I. Fedorova; P. Ya. Poltinin; O. P. Ledenyov

2013-01-24T23:59:59.000Z

296

DASCH ON KU Cyg: A {approx} 5 YEAR DUST ACCRETION EVENT IN {approx} 1900  

SciTech Connect

KU Cyg is an eclipsing binary consisting of an F-type star accreting through a large accretion disk from a K5III red giant. Here we present the discovery of a 5 year dip around 1900 found from its 100 year DASCH light curve. It showed a {approx}0.5 mag slow fading from 1899 to 1903 and brightened back around 1904 on a relatively shorter timescale. The light curve shape of the 1899-1904 fading-brightening event differs from the dust production and dispersion process observed in R Coronae Borealis stars, which usually has a faster fading and slower recovery, and for KU Cyg is probably related to the accretion disk surrounding the F star. The slow fading in KU Cyg is probably caused by increases in dust extinction in the disk, and the subsequent quick brightening may be due to the evaporation of dust transported inward through the disk. The extinction excess which caused the fading may arise from increased mass transfer rate in the system or from dust clump ejections from the K giant.

Tang Sumin; Grindlay, Jonathan; Los, Edward; Servillat, Mathieu, E-mail: stang@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2011-09-01T23:59:59.000Z

297

Comparison of dust from HVAC filters, indoor surfaces, and indoor air Federico Noris*  

E-Print Network (OSTI)

Comparison of dust from HVAC filters, indoor surfaces, and indoor air Federico Noris* , Kerry A and Environmental Engineering * Corresponding email: Fedenoris@mail.utexas.edu SUMMARY HVAC filters are long heavy metal (Pb, Cd and As) concentrations. HVAC filter microbial concentrations appear to be consistent

Siegel, Jeffrey

298

SIMS ISOTOPIC ANALYSIS OF INTERPLANETARY DUST FROM SPACE-EXPOSED AEROGEL. F. J. Stadermann  

E-Print Network (OSTI)

SIMS ISOTOPIC ANALYSIS OF INTERPLANETARY DUST FROM SPACE-EXPOSED AEROGEL. F. J. Stadermann 1: Aerogel is the medium of choice for the intact capture of small particles in space, because it is capable materials [1, 2]. After space-exposed aerogel is returned to the laboratory, the first step of analysis

299

Features of coal dust dynamics at action of differently oriented forces in granular filtering medium  

E-Print Network (OSTI)

The process of the coal dust particles transportation and structurization in the experimental horizontal model of air filter with the cylindrical coal adsorbent granules as in the iodine air filter at the nuclear power plant is researched. In the investigated case the vector of carrying away force of air flow and the vector of gravitation force are mutually perpendicular, and the scattering of the dust particles on the granules occurs in the normal directions. It is found that the phenomenon of non controlled spontaneous sharp increase of aerodynamic resistance in the iodine air filter under the big integral volumes of filtered air and the big masses of introduced coal dust particles is not observed at the described experimental conditions in distinction from the case of the parallel orientation of this forces as in the vertical iodine air filters at the nuclear power plant. The quantitative measurements of the main parameters of the process of the dust masses transportation and structurization are made on a ...

Neklyudov, I M; Poltinin, P Ya; Ledenyov, O P

2013-01-01T23:59:59.000Z

300

THE STRUCTURE OF TWO-PARABOLIC SPACE: PARABOLIC DUST AND ITERATION.  

E-Print Network (OSTI)

THE STRUCTURE OF TWO-PARABOLIC SPACE: PARABOLIC DUST AND ITERATION. JANE GILMAN Abstract. A non-elementary M¨obius group generated by two- parabolics is determined up to conjugation by one complex para] to obtain an additional struc- ture for the parameter space, which we term the two-parabolic space

Gilman, Jane

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

SPITZER CHARACTERIZATION OF DUST IN THE IONIZED MEDIUM OF THE LARGE MAGELLANIC CLOUD  

SciTech Connect

A systematic investigation of dust emission associated with ionized gas has so far been performed only in our Galaxy and for wavelengths longer than 60 {mu}m. Newly available Spitzer data now offer the opportunity to carry out a similar analysis in the Large Magellanic Cloud (LMC). By cross-correlating Spitzer Surveying the Agents of a Galaxy's Evolution (SAGE) data with the Australia Telescope Compact Array/Parkes H I 21 cm data, the NANTEN {sup 12}CO (J = 1-0) data, and both the Southern H-Alpha Sky Survey Atlas H{alpha} and the Parkes 6 cm data, we investigate the physical properties of dust associated with the different phases of the gas (atomic, molecular, and ionized). In particular, we study the presence and nature of dust from 3.6 to 160 {mu}m and for various regimes of ionized gas, spanning emission measures from {approx}1 pc cm{sup -6} (diffuse component) to {approx}10{sup 3}pc cm{sup -6} (H II regions). Using a dust emission model and testing our results with several radiation field spectra, we show that dust in ionized gas is warmer than dust associated with other phases (atomic and molecular). We also find a decrease of the polycyclic aromatic hydrocarbon (PAH) relative abundance with respect to big grains, as well as an increase of the near-infrared (NIR) continuum. These three results (i.e., warmer temperature, decrease of PAH abundance, and increase of the NIR continuum) are found consistently for all regimes of ionized gas. On the contrary, the molecular phase appears to provide favorable conditions for the survival of PAHs. Furthermore, the very small grain relative abundance tends to increase in the ionized phase, especially in bright H II regions. Last but not least, our analysis shows that the emissivity of dust associated with ionized gas is lower in the LMC than in our Galaxy and that this difference is not accounted for by the lower metallicity of the LMC.

Paradis, Deborah; Paladini, Roberta; Noriega-Crespo, Alberto [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Lagache, Guilaine [Institut d'Astrophysique Spatiale, 91405 Orsay (France); Kawamura, Akiko; Fukui, Yasuo [Department of Astrophysics, Nagoya University, Chikusa-ku, Nagoya 464-8602 (Japan); Onishi, Toshikazu [Department of Physical Science, Osaka Prefecture University, Gakuen 1-1, Sakai, Osaka 599-8531 (Japan)

2011-07-01T23:59:59.000Z

302

Reducing the Cost of Solar Cells  

Science Conference Proceedings (OSTI)

Solar-powered electricity prices could soon approach those of power from coal or natural gas thanks to collaborative research with solar startup Ampulse Corporation at the National Renewable Energy Laboratory. Silicon wafers account for almost half the cost of today's solar photovoltaic panels, so reducing or eliminating wafer costs is essential to bringing prices down. Current crystalline silicon technology converts energy in a highly efficient manner; however, that technology is manufactured with processes that could stand some improvement. The industry needs a method that is less complex, creates less waste and uses less energy. First, half the refined silicon is lost as dust in the wafer-sawing process, driving module costs higher. Wafers are sawn off of large cylindrical ingots, or boules, of silicon. A typical 2-meter boule loses as many as 6,000 potential wafers during sawing. Second, the wafers produced are much thicker than necessary. To efficiently convert sunlight into electricity, the wafers need be only one-tenth the typical thickness. NREL, the Oak Ridge National Laboratory and Ampulse have partnered on an approach to eliminate this waste and dramatically lower the cost of the finished solar panels. By using a chemical vapor deposition process to grow the silicon on inexpensive foil, Ampulse is able to make the solar cells just thick enough to convert most of the solar energy into electricity. No more sawdust - and no more wasting refined silicon materials. NREL developed the technology to grow high-quality silicon and ORNL developed the metal foil that has the correct crystal structure to support that growth. Ampulse is installing a pilot manufacturing line in NREL's Process Development Integration Laboratory, where solar companies can work closely with lab scientists on integrated equipment to answer pressing questions related to their technology development, as well as rapidly overcoming R and D challenges and risk. NREL's program is focused on transformative innovation in the domestic PV industry. With knowledge and expertise acquired from the PDIL pilot production line tools, Ampulse plans to design a full-scale production line to accommodate long rolls of metal foil. The Ampulse process 'goes straight from pure silicon-containing gas to high-quality crystal silicon film,' said Brent Nelson, the operational manager for the Process Development Integration Laboratory. 'The advantage is you can make the wafer just as thin as you need it - 10 microns or less.' Most of today's solar cells are made out of wafer crystalline silicon, though thin-film cells made of more exotic elements such as copper, indium, gallium, arsenic, cadmium, tellurium and others are making a strong push into the market. The advantage of silicon is its abundance, because it is derived from sand. Silicon's disadvantage is that purifying it into wafers suitable for solar cells can be expensive and energy intensive. Manufacturers add carbon and heat to sand to produce metallurgical-grade silicon, which is useful in other industries, but not yet suitable for making solar cells. So this metallurgical-grade silicon is then converted to pure trichlorosilane (SiCl3) or silane (SiH4) gas. Typically, the purified gas is then converted to create a silicon feedstock at 1,000 degrees Celsius. This feedstock is melted at 1,414 C and recrystallized into crystal ingots that are finally sawed into wafers. The Ampulse method differs in that it eliminates the last two steps in the traditional process and works directly with the silane gas growing only the needed silicon right onto a foil substrate. A team of NREL scientists had developed a way to use a process called hot-wire chemical vapor deposition to thicken silicon wafers with near perfect crystal structure. Using a hot tungsten filament much like the one found in an incandescent light bulb, the silane gas molecules are broken apart and deposited onto the wafer using the chemical vapor deposition technique at about 700 C - a much lower temperature than needed to make the wafer. The hot filament dec

Scanlon, B.

2012-04-01T23:59:59.000Z

303

Laboratory Measurements and Model Sensitivity Studies of Dust Deposition Ice Nucleation  

Science Conference Proceedings (OSTI)

We investigated the ice nucleating properties of mineral dust particles to understand the sensitivity of simulated cloud properties to two different representations of contact angle in the Classical Nucleation Theory (CNT). These contact angle representations are based on two sets of laboratory deposition ice nucleation measurements: Arizona Test Dust (ATD) particles of 100, 300 and 500 nm sizes were tested at three different temperatures (-25, -30 and -35 C), and 400 nm ATD and kaolinite dust species were tested at two different temperatures (-30 and -35 C). These measurements were used to derive the onset relative humidity with respect to ice (RH{sub ice}) required to activate 1% of dust particles as ice nuclei, from which the onset single contact angles were then calculated based on CNT. For the probability density function (PDF) representation, parameters of the log-normal contact angle distribution were determined by fitting CNT-predicted activated fraction to the measurements at different RH{sub ice}. Results show that onset single contact angles vary from {approx}18 to 24 degrees, while the PDF parameters are sensitive to the measurement conditions (i.e. temperature and dust size). Cloud modeling simulations were performed to understand the sensitivity of cloud properties (i.e. ice number concentration, ice water content, and cloud initiation times) to the representation of contact angle and PDF distribution parameters. The model simulations show that cloud properties are sensitive to onset single contact angles and PDF distribution parameters. The comparison of our experimental results with other studies shows that under similar measurement conditions the onset single contact angles are consistent within {+-}2.0 degrees, while our derived PDF parameters have larger discrepancies.

Kulkarni, Gourihar R.; Fan, Jiwen; Comstock, Jennifer M.; Liu, Xiaohong; Ovchinnikov, Mikhail

2012-08-16T23:59:59.000Z

304

ON ABSORPTION BY CIRCUMSTELLAR DUST, WITH THE PROGENITOR OF SN 2012aw AS A CASE STUDY  

SciTech Connect

We use the progenitor of SN 2012aw to illustrate the consequences of modeling circumstellar dust using Galactic (interstellar) extinction laws that (1) ignore dust emission in the near-IR and beyond, (2) average over dust compositions, and (3) mischaracterize the optical/UV absorption by assuming that scattered photons are lost to the observer. The primary consequences for the progenitor of SN 2012aw are that both the luminosity and the absorption are significantly overestimated. In particular, the stellar luminosity is most likely in the range 10{sup 4.8} < L {sub *}/L {sub Sun} < 10{sup 5.0} and the star was not extremely massive for a Type IIP progenitor, with M {sub *} < 15 M {sub Sun }. Given the properties of the circumstellar dust and the early X-ray/radio detections of SN 2012aw, the star was probably obscured by an ongoing wind with M-dot {approx}10{sup -5.5} to 10{sup -5.0} M {sub Sun} yr{sup -1} at the time of the explosion, roughly consistent with the expected mass-loss rates for a star of its temperature (T{sub *} {approx_equal} 3600{sup +300} {sub -200} K) and luminosity. In the spirit of Galactic extinction laws, we supply simple interpolation formulae for circumstellar extinction by dusty graphitic and silicate shells as a function of wavelength ({lambda} {>=} 0.3 {mu}m) and total (absorption plus scattering) V-band optical depth ({tau}{sub V} {<=} 20). These do not include the contributions of dust emission, but provide a simple, physical alternative to incorrectly using interstellar extinction laws.

Kochanek, C. S.; Khan, R. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Dai, X. [Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks Street, Norman, OK 73019 (United States)

2012-11-01T23:59:59.000Z

305

Hot defluorination of reducing gases with lime pellets  

SciTech Connect

In IGCC and MCFC power generation systems the coal gas has to be purified from dust and deleterious gaseous species. Hot gas cleaning processes have advantages compared to conventional wet cleaning technologies. Losses of energy occurring during cooling and reheating of the gas can be avoided, and there is no formation of a wet slurry. In the present study the defluorination of reducing gases with dry absorbers such as calcium carbonate (CaCO{sub 3}) and calcium oxide (CaO) has been investigated in the temperature range 300--700 C. Two types of experiments were carried out to clarify the reaction kinetics: thermogravimetric experiments on single (or a few) pellets in which the weight change of the absorber due to its conversion to calcium fluoride was determined, and gas cleaning experiments using a laboratory scale fixed bed reactor in which the off-gas was analyzed. The results indicate that H{sub 2}-H{sub 2}O-HF and CO-H{sub 2}-CO{sub 2}-H{sub 2}O-HF gas mixtures can be defluorinated both with CaO and with CaCO{sub 3}. The calcium fluoride (CaF{sub 2}) forms as a shell around the unreacted core of calcium carbonate of the pellet, and the reaction rate is mainly controlled by gaseous pore diffusion. This is so also with respect to calcium oxide at high temperatures (500 C). But at low temperatures (300 C) the reaction occurs within the bulk of the pellet.

Shirai, H.; Fusch, Y.; Schwerdtfeger, K.

2000-03-01T23:59:59.000Z

306

SYSTEMATIC BLUESHIFT OF LINE PROFILES IN THE TYPE IIn SUPERNOVA 2010jl: EVIDENCE FOR POST-SHOCK DUST FORMATION?  

Science Conference Proceedings (OSTI)

Type IIn supernovae (SNe) show spectral evidence for strong interaction between their blast wave and dense circumstellar material (CSM) around the progenitor star. SN 2010jl was the brightest core-collapse supernova in 2010, and it was a Type IIn explosion with strong CSM interaction. Andrews et al. recently reported evidence for an infrared (IR) excess in SN 2010jl, indicating either new dust formation or the heating of CSM dust in an IR echo. Here we report multi-epoch spectra of SN 2010jl that reveal the tell-tale signature of new dust formation: emission-line profiles becoming systematically more blueshifted as the red side of the line is blocked by increasing extinction. The effect is seen clearly in the intermediate-width (400-4000 km s{sup -1}) component of H{alpha} beginning roughly 30 days after explosion. Moreover, we present near-IR spectra demonstrating that the asymmetry in the hydrogen-line profiles is wavelength dependent, appearing more pronounced at shorter wavelengths. This evidence suggests that new dust grains had formed quickly in the post-shock shell of SN 2010jl arising from CSM interaction. Since the observed dust temperature has been attributed to an IR echo and not to new dust, either (1) IR excess emission at {lambda} < 5 {mu}m is not a particularly sensitive tracer of new dust formation in SNe, or (2) some assumptions about expected dust temperatures might require further study. Lastly, we discuss one possible mechanism other than dust that might lead to increasingly blueshifted line profiles in SNe IIn, although the wavelength dependence of the asymmetry argues against this hypothesis in the case of SN 2010jl.

Smith, Nathan; Bian, Fuyan; Weiner, Benjamin J. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Silverman, Jeffrey M.; Filippenko, Alexei V. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Cooper, Michael C. [Department of Physics and Astronomy, University of California, 4129 Frederick Reines Hall, Irvine, CA 92697-4575 (United States); Matheson, Thomas [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719-4933 (United States); Comerford, Julia M., E-mail: nathans@as.arizona.edu [Astronomy Department, University of Texas, Austin, TX 78712 (United States)

2012-01-15T23:59:59.000Z

307

SunShot Initiative: Reducing Photovoltaic Costs  

NLE Websites -- All DOE Office Websites (Extended Search)

Reducing Photovoltaic Costs to Reducing Photovoltaic Costs to someone by E-mail Share SunShot Initiative: Reducing Photovoltaic Costs on Facebook Tweet about SunShot Initiative: Reducing Photovoltaic Costs on Twitter Bookmark SunShot Initiative: Reducing Photovoltaic Costs on Google Bookmark SunShot Initiative: Reducing Photovoltaic Costs on Delicious Rank SunShot Initiative: Reducing Photovoltaic Costs on Digg Find More places to share SunShot Initiative: Reducing Photovoltaic Costs on AddThis.com... Concentrating Solar Power Photovoltaics Research & Development Competitive Awards Systems Integration Balance of Systems Reducing Photovoltaic Costs Photo of gloved hands pouring liquid from a glass bottle to glass beaker. Past Incubator awardee, Innovalight, is creating high-efficiency, low-cost

308

Reducing Your Electricity Use | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Reducing Your Electricity Use Reducing Your Electricity Use Reducing Your Electricity Use July 15, 2012 - 4:11pm Addthis An energy audit can help you find the most effective ways to save money and reduce energy use in your home. | Photo courtesy of Dennis Schroeder, NREL. An energy audit can help you find the most effective ways to save money and reduce energy use in your home. | Photo courtesy of Dennis Schroeder, NREL. What are the key facts? Reducing energy saves money and reduces pollution. When considering a renewable energy system purchase for your home, the first step is to lower your energy use through efficiency measures. Energy audits can help point you to the most effective ways to reduce energy in your home. Reducing energy use in your home saves you money, increases our energy

309

Alternative Fuels Data Center: Reduced Biofuels Tax  

Alternative Fuels and Advanced Vehicles Data Center (EERE)

Reduced Biofuels Tax Reduced Biofuels Tax to someone by E-mail Share Alternative Fuels Data Center: Reduced Biofuels Tax on Facebook Tweet about Alternative Fuels Data Center: Reduced Biofuels Tax on Twitter Bookmark Alternative Fuels Data Center: Reduced Biofuels Tax on Google Bookmark Alternative Fuels Data Center: Reduced Biofuels Tax on Delicious Rank Alternative Fuels Data Center: Reduced Biofuels Tax on Digg Find More places to share Alternative Fuels Data Center: Reduced Biofuels Tax on AddThis.com... More in this section... Federal State Advanced Search All Laws & Incentives Sorted by Type Reduced Biofuels Tax A tax of $0.12 per gallon is imposed on gasoline containing at least 70% ethanol (E70) and diesel fuel containing at least 5% biodiesel (B5). This is a $0.07 discount compared to the conventional gasoline tax of $0.19 per

310

Reducing Your Electricity Use | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Reducing Your Electricity Use Reducing Your Electricity Use Reducing Your Electricity Use July 15, 2012 - 4:11pm Addthis An energy audit can help you find the most effective ways to save money and reduce energy use in your home. | Photo courtesy of Dennis Schroeder, NREL. An energy audit can help you find the most effective ways to save money and reduce energy use in your home. | Photo courtesy of Dennis Schroeder, NREL. What are the key facts? Reducing energy saves money and reduces pollution. When considering a renewable energy system purchase for your home, the first step is to lower your energy use through efficiency measures. Energy audits can help point you to the most effective ways to reduce energy in your home. Reducing energy use in your home saves you money, increases our energy

311

Performance characteristics of PM??? samplers in the presence of agricultural dusts  

E-Print Network (OSTI)

The EPA revised the National Ambient Air Quality Standard (NAAQS) in 1997 to include a standard for fine particulates (PM???), and was unanimously upheld by the US Supreme Court in February of 2001. The long-term standard was set at 15 mg/scm, and the short-term standard was set at 65 mg/scm. A PM??? sampler was developed for the Federal Reference Method shortly after the revision of the NAAQS, and was mandated "by design" rather than "by performance," due to the limited available performance data. Methods for determining PM??? concentrations in the ambient air are designated as either reference or equivalent methods. Accuracy of the subject method is determined by collocating the subject method with a FRM sampler in an urban environment. However, these samplers are not tested in the presence of agriculture dusts, which have a larger mass median diameter (MMD) than urban dusts. This research addressed the performance characteristics of PM??? samplers in the presence of agricultural dusts. Tests in a controlled laboratory environment were performed on three PM??? samplers: a FRM sampler with Wells Impactor Ninety-Six, a FRM sampler with Sharp-Cut Cyclone, and a High-Volume PM??? Sampler. Three dusts were used for sampling: alumina, corn starch, and wheat flour. Ten replications were performed for each sampler in each dust for a total of ninety replications. Performance characteristics, by way of fractional efficiency curves, could not be determined for all of the samplers. The cut-point and slope for the FRM sampler with WINS were found to be 1.95 ± 0.10 [u]m and 1.31 ± 0.04, respectively. Concentration measurements for the test samplers were compared to the "true" PM??? concentrations, determined by multiplying the fraction less than 10 [u]m from the Coulter Counter PSD times the TSP concentration. The results showed the percent error of the PM??? samplers increased with the MMD of the dust sampled. The hypothesis was that the PM??? samplers used to monitor PM??? concentrations in the ambient air will not accurately perform in an agricultural environment. It was concluded that the use of these PM??? samplers would result in unfair regulation of the agricultural industry.

Pargmann, Amber Rae

2001-01-01T23:59:59.000Z

312

DRAFT Outline - Preliminary Framework to Reduce Cyber ...  

Science Conference Proceedings (OSTI)

Page 1. 1 DRAFT Outline - Preliminary Framework to Reduce Cyber Risks to Critical Infrastructure, July 1, 2013 NOTES ...

2013-07-02T23:59:59.000Z

313

Method for Reducing Surface Electromigration Through Chemical ...  

Method for Reducing Surface Electromigration Through Chemical Impurity Optimization Note: The technology described above is an early stage ...

314

Feedstocks with Reduced Acetylation for Higher Product ...  

Biomass and Biofuels Feedstocks with Reduced Acetylation for Higher Product Yields and Improved Properties Lawrence Berkeley National Laboratory.

315

Reduce Pumping Costs through Optimum Pipe Sizing  

SciTech Connect

BestPractices Program tip sheet discussing pumping system efficiency by reducing pumping costs through optimum pipe sizing.

2005-10-01T23:59:59.000Z

316

On Truth-Table Reducibility to SAT  

E-Print Network (OSTI)

We show that polynomial time truth-table reducibility via Boolean circuits to SAT is the same as logspace truth-table reducibility via Boolean formulas to SAT and the same as logspace Turing reducibility to SAT . In addition, we prove that a constant number of rounds of parallel queries to SAT is equivalent to one round of parallel queries.

Samuel Buss; Louise Hay

2002-01-01T23:59:59.000Z

317

MARLA: MapReduce for Heterogeneous Clusters  

Science Conference Proceedings (OSTI)

MapReduce has gradually become the framework of choice for "big data". The MapReduce model allows for efficient and swift processing of large scale data with a cluster of compute nodes. However, the efficiency here comes at a price. The performance of ... Keywords: MapReduce, MARLA, MARIANE, HADOOP

Zacharia Fadika; Elif Dede; Jessica Hartog; Madhusudhan Govindaraju

2012-05-01T23:59:59.000Z

318

Aerosol Radiative Forcing and Forcing Efficiency in the UVB for Regions Affected by Saharan and Asian Mineral Dust  

Science Conference Proceedings (OSTI)

The influence of mineral dust on ultraviolet energy transfer is studied for two different mineralogical origins. The aerosol radiative forcing ?F and the forcing efficiency at the surface ?Feff in the range 290–325 nm were estimated in ground-...

O. E. García; A. M. Díaz; F. J. Expósito; J. P. Díaz; A. Redondas; T. Sasaki

2009-04-01T23:59:59.000Z

319

A Simulated Climatology of Asian Dust Aerosol and Its Trans-Pacific Transport. Part I: Mean Climate and Validation  

Science Conference Proceedings (OSTI)

The Northern Aerosol Regional Climate Model (NARCM) was used to construct a 44-yr climatology of spring Asian dust aerosol emission, column loading, deposition, trans-Pacific transport routes, and budgets during 1960–2003. Comparisons with ...

T. L. Zhao; S. L. Gong; X. Y. Zhang; J-P. Blanchet; I. G. McKendry; Z. J. Zhou

2006-01-01T23:59:59.000Z

320

Impact of Shortwave Radiative Effects of Dust Aerosols on the Summer Season Heat Low over Saudi Arabia  

Science Conference Proceedings (OSTI)

A two-stream scattering scheme based on the delta-Eddington approximation is incorporated into the Florida State University Limited Area Model for computing the shortwave radiative fluxes due to dust aerosols over the Saudi Arabian region and to ...

Saad Mohalfi; H. S. Bedi; T. N. Krishnamurti; Steven D. Cocke

1998-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Direct Radiative Effect of Mineral Dust on the Development of African Easterly Waves in Late Summer, 2003–07  

Science Conference Proceedings (OSTI)

Episodic events of both Saharan dust outbreaks and African easterly waves (AEWs) are observed to move westward over the eastern tropical Atlantic Ocean. The relationship between the warm, dry, and dusty Saharan air layer on the nearby storms has ...

Po-Lun Ma; Kai Zhang; Jainn Jong Shi; Toshihisa Matsui; Albert Arking

2012-12-01T23:59:59.000Z

322

Sensitivity Studies of the Importance of Dust Ice Nuclei for the Indirect Aerosol Effect on Stratiform Mixed-Phase Clouds  

Science Conference Proceedings (OSTI)

New parameterizations of contact freezing and immersion freezing in stratiform mixed-phase clouds (with temperatures between 0° and ?35°C) for black carbon and mineral dust assumed to be composed of either kaolinite (simulation KAO) or ...

U. Lohmann; K. Diehl

2006-03-01T23:59:59.000Z

323

Seeding Effectiveness?The Interaction of Desert Dust and the Southern Margins of Rain Cloud Systems in Israel  

Science Conference Proceedings (OSTI)

Statistical analyses suggest that cloud seeding has caused a net increase of rainfall only in northern Israel. These analyses also identify the reported desert dust as a detrimental factor for the seeding effectiveness. This paper deals with the ...

Daniel Rosenfeld; Ronit Nirel

1996-09-01T23:59:59.000Z

324

Possible Influences of Volcanic Dust Veils or Changes in Solar Luminosity on Long-term Local Temperature Records  

Science Conference Proceedings (OSTI)

Two external forcing functions are examined in their relationship to temperature records at individual locations. Postulated changes in solar luminosity, deduced from sunspot structure, and the dust veil hypothesis are separately considered as ...

Douglas V. Hoyt; Richard A. Siquig

1982-03-01T23:59:59.000Z

325

Airborne Asian Dust: Case Study of Long-Range Transport and Implications for the Detection of Volcanic Ash  

Science Conference Proceedings (OSTI)

The transport of fine-grained Asian dust from its source (e.g., the Gobi Desert, Mongolia) to North America is a common springtime phenomenon. Because of its chemical composition (silicon, iron, aluminum, and calcium) and its particle size ...

J. J. Simpson; G. L. Hufford; R. Servranckx; J. Berg; D. Pieri

2003-04-01T23:59:59.000Z

326

Effects of mineral aerosols on the summertime climate of southwest Asia: Incorporating subgrid variability in a dust emission scheme  

E-Print Network (OSTI)

[1] Improvements in modeling mineral aerosols over southwest Asia are made to the dust scheme in a regional climate model by representing subgrid variability of both wind speed and surface roughness length. The new module ...

Marcella, Marc Pace

327

THE MILKY WAY TOMOGRAPHY WITH SLOAN DIGITAL SKY SURVEY. IV. DISSECTING DUST  

SciTech Connect

We use Sloan Digital Sky Survey (SDSS) photometry of 73 million stars to simultaneously constrain best-fit main-sequence stellar spectral energy distribution (SED) and amount of dust extinction along the line of sight toward each star. Using a subsample of 23 million stars with Two Micron All Sky Survey (2MASS) photometry, whose addition enables more robust results, we show that SDSS photometry alone is sufficient to break degeneracies between intrinsic stellar color and dust amount when the shape of extinction curve is fixed. When using both SDSS and 2MASS photometry, the ratio of the total to selective absorption, R{sub V} , can be determined with an uncertainty of about 0.1 for most stars in high-extinction regions. These fits enable detailed studies of the dust properties and its spatial distribution, and of the stellar spatial distribution at low Galactic latitudes (|b| < 30 Degree-Sign ). Our results are in good agreement with the extinction normalization given by the Schlegel et al. (SFD) dust maps at high northern Galactic latitudes, but indicate that the SFD extinction map appears to be consistently overestimated by about 20% in the southern sky, in agreement with recent study by Schlafly et al. The constraints on the shape of the dust extinction curve across the SDSS and 2MASS bandpasses disfavor the reddening law of O'Donnell, but support the models by Fitzpatrick and Cardelli et al. For the latter, we find a ratio of the total to selective absorption to be R{sub V} = 3.0 {+-} 0.1(random){+-}0.1 (systematic) over most of the high-latitude sky. At low Galactic latitudes (|b| < 5 Degree-Sign ), we demonstrate that the SFD map cannot be reliably used to correct for extinction because most stars are embedded in dust, rather than behind it, as is the case at high Galactic latitudes. We analyze three-dimensional maps of the best-fit R{sub V} and find that R{sub V} = 3.1 cannot be ruled out in any of the 10 SEGUE stripes at a precision level of {approx}0.1-0.2. Our best estimate for the intrinsic scatter of R{sub V} in the regions probed by SEGUE stripes is {approx}0.2. We introduce a method for efficient selection of candidate red giant stars in the disk, dubbed 'dusty parallax relation', which utilizes a correlation between distance and the extinction along the line of sight. We make these best-fit parameters, as well as all the input SDSS and 2MASS data, publicly available in a user-friendly format. These data can be used for studies of stellar number density distribution, the distribution of dust properties, for selecting sources whose SED differs from SEDs for high-latitude main-sequence stars, and for estimating distances to dust clouds and, in turn, to molecular gas clouds.

Berry, Michael; Ivezic, Zeljko; Brooks, Keira J.; Gibson, Robert R.; Jones, Lynne; Yoachim, Peter; Krughoff, Simon; Connolly, Andrew J.; Loebman, Sarah [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Sesar, Branimir [Division of Physics, Mathematics and Astronomy, Caltech, Pasadena, CA 91125 (United States); Juric, Mario [Harvard College Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Schlafly, Edward F.; Finkbeiner, Douglas [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bellovary, Jillian [Department of Astronomy, University of Michigan, Ann Arbor, MI (United States); Vrbanec, Dijana [Department of Physics, Faculty of Science, University of Zagreb, Bijenicka cesta 32, 10000 Zagreb (Croatia); Beers, Timothy C. [National Optical Astronomy Observatories, Tucson, AZ 85719 (United States); Schneider, Donald P. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Kimball, Amy [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States); Bond, Nicholas A. [Physics and Astronomy Department, Rutgers University, Piscataway, NJ 08854-8019 (United States); Schlegel, David [Lawrence Berkeley National Laboratory, One Cyclotron Road, MS 50R5032, Berkeley, CA 94720 (United States); and others

2012-10-01T23:59:59.000Z

328

The Opacity of Spiral Galaxy Disks: dust opacity from calibrated counts of distant galaxies  

E-Print Network (OSTI)

The opacity of foreground spiral disks can be probed from the number of distant galaxies seen through them. To calibrate this number for effects other than the dust extinction, Gonzalez et al (1998) developed the "Synthetic Field Method". A synthetic field is an extincted Hubble Deep Field added to the science field. The relation between the dimming and the number of retrieved synthetic galaxies calibrates the number found in the science field. Here I present results from counts in 32 HST/WFPC2 fields. The relation between opacity and radius, arm and disk, surface brightness and HI are presented. The opacity is found to be caused by a clumpy distribution of clouds in the disk. The brighter parts of the disk -the center and arms- are also the more opaque ones. The dust distribution in spiral disks is found to be more extended than the stellar disk. A comparison between HI column densities and opacity shows little relation between the two.

B. W. Holwerda; R. A. Gonzalez; Ronald J. Allen; P. C. van der Kruit

2005-08-11T23:59:59.000Z

329

Charging of insulating and conducting dust grains by flowing plasma and photoemission  

E-Print Network (OSTI)

The charging of conducting or alternatively insulating dust grains in a supersonic plasma flow with a directed photon flux is studied by the particle-in-cell method. The electron emission modifies the surface charge distribution on a grain and in the surrounding plasma. The charge and potential distributions on and around a dust grain are studied for different photon fluxes and different angles of the incident unidirectional photons with respect to the plasma flow velocity vector. Continuous and pulsed radiations are considered. We show that photoemission allows controlling the charge on conducting grains, and discuss the charging of stationary and spinning insulating grains. Interactions between positively charged grains can be stronger than for negatively charged grains. The simulations are carried out in two spatial dimensions, treating ions and electrons as individual particles.

Miloch, W J; Pecseli, H L; Trulsen, J

2009-01-01T23:59:59.000Z

330

Carbon formation and metal dusting in hot-gas cleanup systems of coal gasifiers  

SciTech Connect

The product gas resulting from the partial oxidation of Carboniferous materials in a gasifier is typically characterized by high carbon and sulfur, but low oxygen, activities and, consequently, severe degradation of the structural and functional materials can occur. The objective of this task was to establish the potential risks of carbon deposition and metal dusting in advanced coal gasification processes by examining the current state of knowledge regarding these phenomena, making appropriate thermochemical calculations for representative coal gasifiers, and addressing possible mitigation methods. The paper discusses carbon activities, iron-based phase stabilities, steam injection, conditions that influence kinetics of carbon deposition, and influence of system operating parameters on carbon deposition and metal dusting.

Judkins, R.R.; Tortorelli, P.F.; Judkins, R.R.; DeVan, J.H.; Wright, I.G. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

1995-11-01T23:59:59.000Z

331

Co-combustion of pellets from Soma lignite and waste dusts of furniture works  

Science Conference Proceedings (OSTI)

In this work, volatiles and char combustion behaviors of the fuel pellets prepared from a low quality lignite and the dusts of furniture works and their various blends were investigated in an experimental fixed bed combustion system through which air flowed by natural convection. Combustion data obtained for varied bed temperatures, mass of pellets, and blend compositions has showed that ignition times of the pellets decreased and volatiles combustion rates tended to increase with the burning temperature. It was concluded that some synergy had existed between lignite and lower ratios of furniture work dusts, which was indicated by a prompt effect on the volatiles combustion rates. Char combustion rates of blend pellets have depended predominantly on the amount of lignite in the blend. The amounts of combustion residues of the pellets were considerably higher than those calculated from individual ash contents of the raw materials and related to lignite ratio in the blends.

Deveci, N.D.; Yilgin, M.; Pehlivan, D. [Firat University, Elazig (Turkey). Faculty of Engineering

2008-07-01T23:59:59.000Z

332

THE STRUCTURE OF TWO-PARABOLIC SPACE: PARABOLIC DUST AND ITERATION.  

E-Print Network (OSTI)

Abstract. A non-elementary Möbius group generated by twoparabolics is determined up to conjugation by one complex parameter and the parameter space has been extensively studied. In this paper, we use the results of [7] to obtain an additional structure for the parameter space, which we term the two-parabolic space. This structure allows us to identify groups that contain additional conjugacy classes of primitive parabolics, which following [14] we call parabolic dust groups, non-free groups off the real axis, and groups that are both parabolic dust and non-free; some of these contain Z × Z subgroups. The structure theorem also attaches additional geometric structure to discrete and non-discrete groups lying in given regions of the parameter space including a new explicit construction of some non-classical T-Schottky groups. 1.

Jane Gilman

2007-01-01T23:59:59.000Z

333

Arbitrary amplitude dust ion acoustic solitary waves in a magnetized suprathermal dusty plasma  

Science Conference Proceedings (OSTI)

The linear and nonlinear dust-ion-acoustic (DIA) wave propagating obliquely with respect to an external magnetic field is studied in a magnetized complex plasma which consists of a cold ion fluid, superthermal electrons, and static dust particles. The propagation properties of two possible modes (in the linear regime) are investigated. It is found that the electron suprathermality and the electron population decrease the phase velocities of both modes, while obliqueness leads to increase of separation between two modes. An energy-like equation derived to describe the nonlinear evolution of DIA solitary waves. The influences of electron suprathermality, obliqueness, and electron population on the existence domain of solitary waves and the soliton characteristics are examined. It is shown that the existence domain of the DIA soliton and its profile are significantly depending on the deviation of electrons from thermodynamic equilibrium, electrons population, and obliqueness. It is also found that the suprathermal plasma supports the DIA solitons with larger amplitude.

Shahmansouri, M. [Department of Physics, Faculty of Science, Arak University, Arak 38156-8-8349 (Iran, Islamic Republic of); Alinejad, H. [Department of Physics, Faculty of Basic Science, Babol University of Technology, Babol 47148-71167, Iran and Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), P.O. Box 55134-441, Maragha (Iran, Islamic Republic of)

2012-12-15T23:59:59.000Z

334

High Resolution Millimeter-Wave Mapping of Linearly Polarized Dust Emission: Magnetic Field Structure in Orion  

E-Print Network (OSTI)

We present 1.3 and 3.3 mm polarization maps of Orion-KL obtained with the BIMA array at approximately 4 arcsec resolution. Thermal emission from magnetically aligned dust grains produces the polarization. Along the Orion ``ridge'' the polarization position angle varies smoothly from about 10 degrees to 40 degrees, in agreement with previous lower resolution maps. In a small region south of the Orion ``hot core,'' however, the position angle changes by 90 degrees. This abrupt change in polarization direction is not necessarily the signpost of a twisted magnetic field. Rather, in this localized region processes other than the usual Davis-Greenstein mechanism might align the dust grains with their long axes parallel with the field, orthogonal to their normal orientation.

R. Rao; R. M. Crutcher; R. L. Plambeck; M. C. H. Wright

1998-05-21T23:59:59.000Z

335

Nonplanar dust acoustic solitary waves in dusty plasmas with ions and electrons following a q-nonextensive distribution  

Science Conference Proceedings (OSTI)

Cylindrical and spherical Korteweg-de Vries equations are derived for dust acoustic solitary waves in an unmagnetized three species plasma system, comprised of negatively charged cold dust, nonextensive ions and nonextensive electrons using standard reductive perturbation method. The effects of q{sub e}-nonextensive electrons, q{sub i}-nonextensive ions, electron-to-ion number density ratio {mu}, and nonplanar geometry on the profiles of the amplitudes of the solitary structures are examined numerically.

Eslami, Parvin [Department of Physics, Ferdowsi University of Mashhad (Iran, Islamic Republic of); Mottaghizadeh, Marzieh [Department of Physics, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of); Pakzad, Hamid Reza [Department of Physics, Bojnourd Branch, Islamic Azad University, Bojnourd (Iran, Islamic Republic of)

2011-10-15T23:59:59.000Z

336

AN INTERMEDIATE LUMINOSITY TRANSIENT IN NGC 300: THE ERUPTION OF A DUST-ENSHROUDED MASSIVE STAR  

SciTech Connect

We present multi-epoch high-resolution optical spectroscopy, UV/radio/X-ray imaging, and archival Hubble and Spitzer observations of an intermediate luminosity optical transient recently discovered in the nearby galaxy NGC 300. We find that the transient (NGC 300 OT2008-1) has a peak absolute magnitude of M{sub bol} {approx} -11.8 mag, intermediate between novae and supernovae, and similar to the recent events M85 OT2006-1 and SN 2008S. Our high-resolution spectra, the first for this event, are dominated by intermediate velocity ({approx}200-1000 km s{sup -1}) hydrogen Balmer lines and Ca II emission and absorption lines that point to a complex circumstellar environment, reminiscent of the yellow hypergiant IRC+10420. In particular, we detect asymmetric Ca II H and K absorption with a broad red wing extending to {approx}10{sup 3} km s{sup -1}, indicative of gas inflow at high velocity (possibly the wind of a massive binary companion). The low luminosity, intermediate velocities, and overall similarity to a known eruptive star indicate that the event did not result in a complete disruption of the progenitor. We identify the progenitor in archival Spitzer observations, with deep upper limits from Hubble data. The spectral energy distribution points to a dust-enshrouded star with a luminosity of about 6 x 10{sup 4} L{sub sun}, indicative of a {approx}10-20 M{sub sun} progenitor (or binary system). This conclusion is in good agreement with our interpretation of the outburst and circumstellar properties. The lack of significant extinction in the transient spectrum indicates that the dust surrounding the progenitor was cleared by the outburst. We thus predict that the progenitor should be eventually visible with Hubble if the transient event marks an evolutionary transition to a dust-free state, or with Spitzer if the event marks a cyclical process of dust formation.

Berger, E.; Soderberg, A. M.; Foley, R. J.; Dupree, A. K. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Chevalier, R. A. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Fransson, C. [Department of Astronomy, Stockholm University, AlbaNova, SE-106 91 Stockholm (Sweden); Leonard, D. C. [Department of Astronomy, San Diego State University, PA-210, 5500 Campanile Drive, San Diego, CA 92182-1221 (United States); Debes, J. H. [Carnegie Institution of Washington, Department of Terrestrial Magnetism, 5241 Broad Branch Road, Washington, DC 20015 (United States); Diamond-Stanic, A. M.; Tremonti, C. A. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Ivans, I. I.; Thompson, I. B. [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Simmerer, J. [Lund Observatory, Box 43, SE-221 00 Lund (Sweden)

2009-07-10T23:59:59.000Z

337

Dust removal in radio-frequency plasmas by a traveling potential modulation  

Science Conference Proceedings (OSTI)

The dust contamination in plasma deposition processes plays a crucial role in the quality and the yield of the products. To improve the quality and the yield of plasma processing, a favorable way is to remove the dust particles actively from the plasma reactors.Our recent experiments in the striped electrode device show that a traveling plasma modulation allows for a systematic particle removal independent of the reactor size. Besides the rf powered electrode, the striped electrode device includes a segmented electrode that consists of 100 electrically insulated narrow stripes. A traveling potential profile is produced by the modulation of the voltage signals applied on the stripes. The dust particles are trapped in the potential wells and transported with the traveling of the potential profile.The particle-in-cell (PIC) simulation on the potential above the segmented electrode indicates that the traveling potential profile can be realized either by applying low-frequency (0.1-10 Hz) voltage signals with a fixed phase shift between adjacent stripes or high-frequency (10 kHz a circumflex AS 100 MHz) signals with the amplitudes modulated by a low-frequency envelope. The transportation of the dust particles is simulated with a two-dimensional molecular dynamics (MD) code with the potential profile obtained from the PIC simulation. The MD results reproduce the experimental observations successfully.This technology allows for an active removal of the contaminating particles in processing plasmas and it is independent of the reactor size. The removal velocity is controllable by adjusting the parameters for the modulation.

Li Yangfang; Jiang Ke; Thomas, Hubertus M.; Morfill, Gregor E. [Max-Planck-Institute for Extraterrestrial Physics, 85748 Garching (Germany)

2010-06-16T23:59:59.000Z

338

SPITZER 24 {mu}m SURVEY FOR DUST DISKS AROUND HOT WHITE DWARFS  

Science Conference Proceedings (OSTI)

Two types of dust disks around white dwarfs (WDs) have been reported: small dust disks around cool metal-rich WDs consisting of tidally disrupted asteroids and a large dust disk around the hot central WD of the Helix planetary nebula (PN) possibly produced by collisions among Kuiper-Belt-like objects. To search for more dust disks of the latter type, we have conducted a Spitzer MIPS 24 {mu}m survey of 71 hot WDs or pre-WDs, among which 35 are central stars of PNe (CSPNs). Nine of these evolved stars are detected and their 24 {mu}m flux densities are at least two orders of magnitude higher than their expected photospheric emission. Considering the bias against the detection of distant objects, the 24 {mu}m detection rate for the sample is {approx}>15%. It is striking that seven, or {approx}20%, of the WD and pre-WDs in known PNe exhibit 24 {mu}m excesses, while two, or 5%-6%, of the WDs not in PNe show 24 {mu}m excesses and they have the lowest 24 {mu}m flux densities. We have obtained follow-up Spitzer Infrared Spectrograph spectra for five objects. Four show clear continuum emission at 24 {mu}m, and one is overwhelmed by a bright neighboring star but still shows a hint of continuum emission. In the cases of WD 0950+139 and CSPN K 1-22, a late-type companion is present, making it difficult to determine whether the excess 24 {mu}m emission is associated with the WD or its red companion. High-resolution images in the mid-infrared are needed to establish unambiguously the stars responsible for the 24 {mu}m excesses.

Chu, You-Hua; Bilikova, Jana; Gruendl, Robert A. [Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Su, Kate Y. L. [Stewart Observatory, University of Arizona, Tucson, AZ 85721 (United States); De Marco, Orsola [Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109 (Australia); Guerrero, Martin A. [Instituto de Astrofisica de Andalucia, CSIC, E-18008 Granada (Spain); Updike, Adria C. [CRESST and the Observational Cosmology Laboratory, NASA/GSFC, Greenbelt, MD 20771 (United States); Volk, Kevin [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Rauch, Thomas, E-mail: yhchu@illinois.edu [Institut fuer Astronomie und Astrophysik Tuebingen (IAAT), Abteilung Astronomie, D-72076 Tuebingen (Germany)

2011-09-15T23:59:59.000Z

339

CONTROL OF INTERFACIAL DUST CAKE TO IMPROVE EFFICIENCY OF MOVING BED GRANULAR FILTERS  

Science Conference Proceedings (OSTI)

The goal of this research is to improve the performance of moving bed granular filters for gas cleaning at high temperatures and pressures. A second objective is to better understand dust capture interfacial phenomena and cake formation in moving bed filters. The experimental bed tested in the present study has several unique design features configured as cold flow, axially symmetric, counter-current flow to simulate a filter operating at high temperatures (1088 K) and elevated pressures (10 atmospheres). The granular filter is evaluated in two separate performance studies: (1) optimization of particle collection efficiency and bed pressure drop in a factorial study at near-atmospheric operating pressures through appropriate use of granular bed materials, particle sizes, and feed rates; and (2) high temperature and high pressure model simulation conducted at above-atmospheric pressures and room temperature utilizing dust and granular flow rates, granular size, system pressure, and superficial velocity. The factorial study involves a composite design of 16 near-atmospheric tests, while the model simulation study is comprised of 7 above-atmospheric tests. Similarity rules were validated in tests at four different mass dust ratios and showed nearly constant collection efficiencies ({approx} 99.5 {+-} 0.3%) for operating pressures of 160 kPa gage (23.2 psig) at room temperature (20 C), which simulates the hydrodynamic conditions expected for typical gasification streams (1088 K, 10 atmospheres). An important outcome from the near-atmospheric pressure studies are relationships developed using central composite design between the independent variables, superficial velocity (0.16-0.22 m/s), dust feed rate (0.08-0.74 kg/hr), and granular flow rate (3.32-15.4 kg/hr). These operating equations were optimized in contour plots for bed conditions that simultaneously satisfy low-pressure drop and high particle collection efficiency.

Robert C. Brown; Gerald M. Colver

2002-10-31T23:59:59.000Z

340

MULTIBAND OPTICAL OBSERVATION OF THE P/2010 A2 DUST TAIL  

SciTech Connect

An inner main-belt asteroid, P/2010 A2, was discovered on 2010 January 6. Based on its orbital elements, it is considered that the asteroid belongs to the Flora collisional family, where S-type asteroids are common, while showing a comet-like dust tail. Although analysis of images taken by the Hubble Space Telescope and Rosetta spacecraft suggested that the dust tail resulted from a recent head-on collision between asteroids, an alternative idea of ice sublimation was suggested based on the morphological fitting of ground-based images. Here, we report a multiband observation of P/2010 A2 made on 2010 January with a 105 cm telescope at the Ishigakijima Astronomical Observatory. Three broadband filters, g', R{sub c} , and I{sub c} , were employed for the observation. The unique multiband data reveal that the reflectance spectrum of the P/2010 A2 dust tail resembles that of an Sq-type asteroid or that of ordinary chondrites rather than that of an S-type asteroid. Due to the large error of the measurement, the reflectance spectrum also resembles the spectra of C-type asteroids, even though C-type asteroids are uncommon in the Flora family. The reflectances relative to the g' band (470 nm) are 1.096 {+-} 0.046 at the R{sub c} band (650 nm) and 1.131 {+-} 0.061 at the I{sub c} band (800 nm). We hypothesize that the parent body of P/2010 A2 was originally S-type but was then shattered upon collision into scattering fresh chondritic particles from the interior, thus forming the dust tail.

Kim, Junhan [303-201, Mokdong Apartment, Mok-5-dong, Yangcheon-gu, Seoul 158-753 (Korea, Republic of); Ishiguro, Masateru [Department of Physics and Astronomy, Seoul National University, San 56-1, Silim-dong, Gwanak-gu, Seoul 151-742 (Korea, Republic of); Hanayama, Hidekazu [Ishigakijima Astronomical Observatory, National Astronomical Observatory of Japan, Ishigaki, Okinawa 907-0024 (Japan); Hasegawa, Sunao; Usui, Fumihiko; Sarugaku, Yuki [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Yanagisawa, Kenshi [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Asaguchi, Okayama 719-0232 (Japan); Watanabe, Jun-ichi [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Yoshida, Michitoshi, E-mail: ishiguro@astro.snu.ac.kr [Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)

2012-02-10T23:59:59.000Z

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Investigation of plasma-dust structures in He-Ar gas mixture  

SciTech Connect

The paper reports on the first experiments with plasma-dust formations in dc gas discharge plasma for a He-Ar mixture. It is shown that the choice of light and heavy gases for the mixture suppresses ion heating in electric field under the conventional conditions of experiments and results in a supersonic jet with high Mach numbers. Distribution functions for drifting ions in the gas mixture are calculated for various mixture concentrations, electric field strengths, and gas pressures.

Maiorov, S. A. [A.M. Prokhorov General Physics Institute of Russian Academy of Sciences, Moscow (Russian Federation); Ramazanov, T. S.; Dzhumagulova, K. N.; Jumabekov, A. N.; Dosbolayev, M. K. [Al Farabi Kazakh National University, IETP, Tole bi 96a, Almaty, 050012 (Kazakhstan)

2008-09-15T23:59:59.000Z

342

SPITZER AND HERSCHEL MULTIWAVELENGTH CHARACTERIZATION OF THE DUST CONTENT OF EVOLVED H II REGIONS  

SciTech Connect

We have analyzed a uniform sample of 16 evolved H II regions located in a 2 Degree-Sign Multiplication-Sign 2 Degree-Sign Galactic field centered at (l,b) = (30 Degree-Sign , 0 Degree-Sign ) and observed as part of the Herschel Hi-GAL survey. The evolutionary stage of these H II regions was established using ancillary radio-continuum data. By combining Hi-GAL PACS (70 {mu}m, 160 {mu}m) and SPIRE (250 {mu}m, 350 {mu}m, and 500 {mu}m) measurements with MIPSGAL 24 {mu}m data, we built spectral energy distributions of the sources and showed that a two-component gray-body model is a good representation of the data. In particular, wavelengths >70 {mu}m appear to trace a cold dust component, for which we estimated an equilibrium temperature of the big grains (BGs) in the range 20-30 K, while for {lambda} < 70 {mu}m, the data indicate the presence of a warm dust component at temperatures of the order of 50-90 K. This analysis also revealed that dust is present in the interior of H II regions, although likely not in a large amount. In addition, the data seem to corroborate the hypothesis that the main mechanism responsible for the (partial) depletion of dust in H II regions is radiation-pressure-driven drift. In this framework, we speculated that the 24 {mu}m emission that spatially correlates with ionized gas might be associated with either very small grain or BG replenishment, as recently proposed for the case of wind-blown bubbles. Finally, we found that evolved H II regions are characterized by distinctive far-IR and submillimeter colors, which can be used as diagnostics for their identification in unresolved Galactic and extragalactic regions.

Paladini, R. [NASA Herschel Science Center, California Institute of Technology, 1200, East California Boulevard, Pasadena, CA 91125 (United States); Umana, G. [INAF-Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania (Italy); Veneziani, M.; Noriega-Crespo, A. [Infrared Processing and Analysis Center, California Institute of Technology, 1200, East California Boulevard, Pasadena, CA 91125 (United States); Anderson, L. D. [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States); Piacentini, F. [Dipartimento di Fisica, Universita di Roma La Sapienza, I-00185 Roma (Italy); Pinheiro Goncalves, D. [Department of Astronomy and Astrophysics, University of Toronto 50 George Street, Toronto, ON M5S 3H4 (Canada); Paradis, D.; Bernard, J.-P. [Centre d'Etude Spatiale des Rayonnements, 9 Avenue du Colonel Roche, F-31028 Toulouse Cedex 4 (France); Tibbs, C. T. [Spitzer Science Center, California Institute of Technology, 1200, East California Boulevard, Pasadena, CA 91125 (United States); Natoli, P., E-mail: paladini@ipac.caltech.edu [Istituto Nazionale di Fisica Nucleare, Sezione Ferrara, I-44100 Ferrara (Italy)

2012-12-01T23:59:59.000Z

343

Hot Coal for Christmas: Dust Formation in the Swept-Up Shell Around The Peculiar Type Ib Supernova 2006jc  

E-Print Network (OSTI)

We present evidence for the formation of dust grains in an unusual Type Ib SN based on late-time spectra of SN 2006jc. The progenitor suffered a giant outburst qualitatively similar to those seen in LBVs just 2 years prior to the SN, and we speculate that the dust formation we observe is an indirect consequence of that event. The key evidence for dust formation seen in our optical spectra is (1) the appearance of a strong continuum emission source at red wavelengths, and (2) fading of the redshifted sides of narrow HeI emission lines. These two observed characteristics provide the strongest case yet for dust formation in any Type Ib/c SN. Both developments occurred simultaneously between 51 and 75 days after peak brightness, which is quick compared to other dusty SNe. The high temperature of the dust implies carbon and not silicates, and we describe how infrared photometry may test this conjecture. Geometric considerations indicate dust formation occurring in the dense gas swept-up by the forward shock, and n...

Smith, Nathan; Filippenko, Alexei V

2007-01-01T23:59:59.000Z

344

Neutral Solar Wind Generated by Lunar Exospheric Dust at the Terminator  

E-Print Network (OSTI)

We calculate the flux of neutral solar wind observed on the lunar surface at the terminator due to solar wind protons penetrating exospheric dust grains with (1) radii greater than 0.1 microns and (2) radii greater than 0.01 microns. For grains with radii larger than 0.1 microns, the ratio of the neutral solar wind flux produced by exospheric dust to the incident ionized solar wind flux is estimated to be about 10^-4-10^-3 for solar wind speeds in excess of 800 km/s, but much lower (less than 10^-5) at average to slow solar wind speeds. However, when the smaller grain sizes are considered, this ratio is estimated to be greater than 10^-5 at all speeds, and at speeds in excess of 700 km/s reaches about 10^-3. These neutral solar wind fluxes are easily measurable with current low energy neutral atom instrumentation. Observations of neutral solar wind from the surface of the Moon would provide independent information on the distribution of very small dust grains in the lunar exosphere that would complement and c...

Collier, Michael R

2008-01-01T23:59:59.000Z

345

Using Hubble Space Telescope Imaging of Nuclear Dust Morphology to Rule Out Bars Fueling Seyfert Nuclei  

E-Print Network (OSTI)

If AGN are powered by the accretion of matter onto massive black holes, how does the gas in the host galaxy lose the required angular momentum to approach the black hole? Gas easily transfers angular momentum to stars in strong bars, making them likely candidates. Although ground-based searches for bars in active galaxies using both optical and near infrared surface brightness have not found any excess of bars relative to quiescent galaxies, the searches have not been able to rule out small-scale nuclear bars. To look for these nuclear bars we use HST WFPC2-NICMOS color maps to search for the straight dust lane signature of strong bars. Of the twelve Seyfert galaxies in our sample, only three have dust lanes consistent with a strong nuclear bar. Therefore, strong nuclear bars cannot be the primary fueling mechanism for Seyfert nuclei. We do find that a majority of the galaxies show an spiral morphology in their dust lanes. These spiral arms may be a possible fueling mechanism.

Michael W. Regan; John S. Mulchaey

1999-03-03T23:59:59.000Z

346

Dust in the polar region as a major contributor to the IR emission of AGN  

E-Print Network (OSTI)

(abridged) It is generally assumed that the distribution of dust on parsec scales forms a geometrically- and optically-thick entity in the equatorial plane around the accretion disk and broad-line region - dubbed "dust torus" - that emits the bulk of the sub-arcsecond-scale IR emission and gives rise to orientation-dependent obscuration. Here we report detailed interferometry observations of the unobscured (type 1) AGN in NGC 3783 that allow us to constrain the size, elongation, and direction of the mid-IR emission with high accuracy. The mid-IR emission is characterized by a strong elongation toward position angle PA -52 deg, closely aligned with the polar axis (PA -45 deg). We determine half-light radii along the major and minor axes at 12.5 {\\mu}m of (4.23 +/- 0.63) pc x (1.42 +/- 0.21) pc, which corresponds to intrinsically-scaled sizes of (69.4 +/- 10.8) rin x (23.3 +/- 3.5) rin for the inner dust radius of rin = 0.061 pc as inferred from near-IR reverberation mapping. This implies an axis ratio of 3:1, ...

Hoenig, Sebastian F; Tristram, Konrad R W; Prieto, M Almudena; Gandhi, Poshak; Asmus, Daniel; Antonucci, Robert; Burtscher, Leonard; Duschl, Wolfgang J; Weigelt, Gerd

2013-01-01T23:59:59.000Z

347

The parametric decay of Alfven waves into shear Alfven waves and dust lower hybrid waves  

SciTech Connect

The parametric decay instability of Alfven wave into low-frequency electrostatic dust-lower-hybrid and electromagnetic shear Alfven waves has been investigated in detail in a dusty plasma in the presence of external/ambient uniform magnetic field. Magnetohydrodynamic fluid equations of plasmas have been employed to find the linear and nonlinear response of the plasma particles for this three-wave nonlinear coupling in a dusty magnetoplasma. Here, relatively high frequency electromagnetic Alfven wave has been taken as the pump wave. It couples with other two low-frequency internal possible modes of the dusty magnetoplasma, viz., the dust-lower-hybrid and shear Alfven waves. The nonlinear dispersion relation of the dust-lower-hybrid wave has been solved to obtain the growth rate of the parametric decay instability. The growth rate is maximum for small value of external magnetic field B{sub s}. It is noticed that the growth rate is proportional to the unperturbed electron number density n{sub oe}.

Jamil, M. [Department of Physics, Government College University, Lahore 54000 (Pakistan); Department of Physics, Crescent Model School Shadman, Lahore 54000 (Pakistan); Shah, H. A.; Zubia, K.; Zeba, I.; Uzma, Ch. [Department of Physics, Government College University, Lahore 54000 (Pakistan); Salimullah, M. [Department of Physics, Government College University, Lahore 54000 (Pakistan); Department of Physics, Jahangirnagar University, Savar, Dhaka 1342 (Bangladesh)

2010-07-15T23:59:59.000Z

348

Reduce Radiation Losses from Heating Equipment  

Science Conference Proceedings (OSTI)

This DOE Industrial Technologies Program tip sheet describes how to save energy and costs by reducing expensive heat losses from industrial heating equipment, such as furnaces.

Not Available

2006-01-01T23:59:59.000Z

349

Why Sequence Bacteria That Reduce Sulfur Compounds?  

NLE Websites -- All DOE Office Websites (Extended Search)

Bacteria That Reduce Sulfur Compounds? Combustion of sulfur-containing fuels, such as coal, oil, and natural gas, contributes significantly to global environmental problems, such...

350

Reduce Your Burden – Use Magnesium Alloys  

Science Conference Proceedings (OSTI)

Especially in transportation solutions have to be found to reduce the CO2 emissions drastically. This can be done when the weight of airplanes, cars and trucks ...

351

Thermophysical Property Measurements Under Reduced Gravity ...  

Science Conference Proceedings (OSTI)

Presentation Title, Thermophysical Property Measurements Under Reduced Gravity Conditions: Evolution and Status of theThermoLab Project. Author(s), H-J

352

Definition: Reduced Electricity Cost | Open Energy Information  

Open Energy Info (EERE)

Cost Jump to: navigation, search Dictionary.png Reduced Electricity Cost Functions that provide this benefit could help alter customer usage patterns (demand response with price...

353

Reducing Emissions Through Sustainable Transport: Proposal for...  

Open Energy Info (EERE)

Approach Jump to: navigation, search Tool Summary Name: Reducing Emissions Through Sustainable Transport: Proposal for a Sectoral Approach AgencyCompany Organization: GTZ...

354

Partially Reduced Feedstocks and Blast Furnace Ironmaking ...  

Science Conference Proceedings (OSTI)

... Partially Reduced Feedstocks and Blast Furnace Ironmaking Carbon Intensity ... simple Rist-style blast furnace mass and energy balance, assuming furnace ...

355

Definition: Reduced Electricity Theft | Open Energy Information  

Open Energy Info (EERE)

Theft Jump to: navigation, search Dictionary.png Reduced Electricity Theft Smart meters can typically detect tampering. Moreover, a meter data management system can analyze...

356

Definition: Reduced Restoration Cost | Open Energy Information  

Open Energy Info (EERE)

Restoration Cost Jump to: navigation, search Dictionary.png Reduced Restoration Cost The functions that provide this benefit lead to fewer outages andor help restore power quicker...

357

Modeling reducibility on ground terms using constraints  

E-Print Network (OSTI)

Modeling reducibility on ground terms using constraints Isabelle GNAEDIGa , H´el`ene KIRCHNERb a on ground terms using (dis)equational constraints. We show in particular that innermost (ir)reducibility can on the ground term algebra that any rewriting chain starting from any term termi- nates, provided that terms

Paris-Sud XI, Université de

358

Definition: Reduced Electricity Losses | Open Energy Information  

Open Energy Info (EERE)

Losses Losses Jump to: navigation, search Dictionary.png Reduced Electricity Losses Functions that provide this benefit could help manage peak feeder loads, reduced electricity throughput, locate electricity production closer to the load and ensure that voltages remain within service tolerances, while minimizing the amount of reactive power provided. These actions can reduce electricity losses by making the system more efficient for a given load served or by actually reducing the overall load on the system.[1] Related Terms load, electricity generation, reactive power, smart grid References ↑ SmartGrid.gov 'Description of Benefits' An inl LikeLike UnlikeLike You like this.Sign Up to see what your friends like. ine Glossary Definition Retrieved from "http://en.openei.org/w/index.php?title=Definition:Reduced_Electricity_Losses&oldid=502644

359

Measurements of aerosol properties from aircraft, satellite and ground-based remote sensing: a case-study from the Dust and Biomass-burning Experiment (DABEX)  

DOE Green Energy (OSTI)

Measurements of aerosol properties from aircraft, satellite and ground-based remote sensing: A case study from the Dust and Biomass burning Experiment (DABEX)

Johnson, B. T.; Christopher, S.; Haywood, J.; Osborne, S. R.; McFarlane, Sally; Hsu, C.; Salustro, C.; Kahn, Ralph

2009-04-28T23:59:59.000Z

360

Three-dimensional dust radiative-transfer models: The Pinwheel Nebula of WR104  

E-Print Network (OSTI)

We present radiative-transfer modelling of the dusty spiral Pinwheel Nebula observed around the Wolf-Rayet/OB-star binary WR104. The models are based on the three-dimensional radiative-transfer code TORUS, modified to include an adaptive mesh that allows us to adequately resolve both the inner spiral turns (sub-AU scales) and the outer regions of the nebula (distances of 10^4 AU from the central source). The spiral model provides a good fit to both the spectral energy distribution and Keck aperture masking interferometry, reproducing both the maximum entropy recovered images and the visibility curves. We deduce a dust creation rate of 8+-1 x 10^{-7} solar masses per year, corresponding to approximately 2% by mass of the carbon produced by the Wolf-Rayet star. Simultaneous modelling of the imaging and spectral data enables us to constrain both the opening-angle of the wind-wind collision interface and the dust grain size. We conclude that the dust grains in the inner part of the Pinwheel nebula are small (~100A), in agreement with theoretical predictions, although we cannot rule out the presence of larger grains (~1 micron) further from the central binary. The opening angle of the wind-wind collision interface appears to be about 40 degrees, in broad agreement with the wind parameters estimated for the central binary. We discuss the success and deficiencies of the model, and the likely benefits of applying similar techniques to the more the more complex nebulae observed around other WR/O star binaries.

Tim J Harries; John D Monnier; Neil H Symington; Ryuichi Kurosawa

2004-01-27T23:59:59.000Z

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

An extended dust disk in a spiral galaxy; An occulting galaxy pair in ANGST  

E-Print Network (OSTI)

We present an analysis of an occulting galaxy pair, serendipitously discovered in ACS Nearby Galaxy Survey Treasury (ANGST) observations of NGC 253 taken with Hubble Space Telescope's Advanced Camera for Survey in F475W, F606W$ and F814W (SDSS-g, broad V and I). The foreground disk system (at z < 0.06) shows a dusty disk much more extended than the starlight, with spiral lanes seen in extinction out to 1.5 R\\_25, approximately six half-light radii. This pair is the first where extinction can be mapped reliably out to this distance from the center. The spiral arms of the extended dust disk show typical extinction values of A\\_F475W ~ 0.25, A\\_F606W ~ 0.25, and A\\_F814W ~ 0.15. The extinction law inferred from these measures is similar to the local Milky Way one, and we show that the smoothing effects of sampling at limited spatial resolution (<57 pc, in these data) flattens the observed function through mixing of regions with different extinction. This galaxy illustrates the diversity of dust distributions in spirals, and the limitations of adopting a single dust model for optically similar galaxies. The ideal geometry of this pair of overlapping galaxies and the high sampling of HST data make this dataset ideal to analyze this pair with three separate approaches to overlapping galaxies: (A) a combined fit, rotating copies of both galaxies, (B) a simple flip of the background image and (C) an estimate of the original fluxes for the individual galaxies based on reconstructions of their proper isophotes. We conclude that in the case of high quality data such as these, isophotal models are to be preferred.

B. W. Holwerda; W. C. Keel; B. Williams; J. J. Dalcanton; R. S. de Jong

2008-10-15T23:59:59.000Z

362

Techniques for Reducing High Risk Contracting Approaches  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Reducing High Reducing High Risk Contracting Approaches Topics for Discussion Presidential Direction March 4, 2009 * Focus on transparency * Increase competition - It is the policy of the Federal Government that executive agencies shall not engage in noncompetitive contracts except in those circumstances where their use can be fully justified and where appropriate safeguards have been put in place to protect the taxpayer. * Improve competitive environment for the life of multiple award contracts * Reduce risk of cost growth/overcharging * Office of Management and Budget (OMB) Guidance to improve Government Acquisition , 29 July 2009 (implements President's direction) Why the Emphasis? * Reports by agency Inspectors General, the

363

Carbon Formation and Metal Dusting in Hot-Gas Cleanup Systems of Coal Gasifiers  

SciTech Connect

There are several possible materials/systems degradation modes that result from gasification environments with appreciable carbon activities. These processes, which are not necessarily mutually exclusive, include carbon deposition, carburization, metal dusting, and CO disintegration of refractories. Carbon formation on solid surfaces occurs by deposition from gases in which the carbon activity (a sub C) exceeds unity. The presence of a carbon layer CO can directly affect gasifier performance by restricting gas flow, particularly in the hot gas filter, creating debris (that may be deposited elsewhere in the system or that may cause erosive damage of downstream components), and/or changing the catalytic activity of surfaces.

Tortorelli, Peter F.; Judkins, Roddie R.; DeVan, Jackson H.; Wright, Ian G.

1995-12-31T23:59:59.000Z

364

Fluidized bed heat exchanger with water cooled air distributor and dust hopper  

DOE Patents (OSTI)

A fluidized bed heat exchanger is provided in which air is passed through a bed of particulate material containing fuel. A steam-water natural circulation system is provided for heat exchange and the housing of the heat exchanger has a water-wall type construction. Vertical in-bed heat exchange tubes are provided and the air distributor is water-cooled. A water-cooled dust hopper is provided in the housing to collect particulates from the combustion gases and separate the combustion zone from a volume within said housing in which convection heat exchange tubes are provided to extract heat from the exiting combustion gases.

Jukkola, Walfred W. (Westport, CT); Leon, Albert M. (Mamaroneck, NY); Van Dyk, Jr., Garritt C. (Bethel, CT); McCoy, Daniel E. (Williamsport, PA); Fisher, Barry L. (Montgomery, PA); Saiers, Timothy L. (Williamsport, PA); Karstetter, Marlin E. (Loganton, PA)

1981-11-24T23:59:59.000Z

365

Dust-acoustic shock waves in a charge varying electronegative magnetized dusty plasma with suprathermal electrons  

Science Conference Proceedings (OSTI)

The combined effects of an oblique magnetic field and electron suprathermality on weak dust-acoustic (DA) waves in a charge varying electronegative dusty plasmas with application to the Halley Comet are investigated. The correct suprathermal electron charging current is derived based on the orbit-motion limited approach. A weakly nonlinear analysis is carried out to derive a Korteweg-de Vries-Burger equation. The electron suprathermality, the obliqueness, and magnitude of the magnetic field are found to modify the dispersive properties of the DA shock structure. Our results may aid to explain and interpret the nonlinear oscillations that may occur in the Halley Comet plasma.

Tribeche, Mouloud; Bacha, Mustapha [Faculty of Sciences-Physics, Theoretical Physics Laboratory (TPL), Plasma Physics Group (PPG), University of Bab-Ezzouar, USTHB, B.P. 32, El Alia, Algiers 16111 (Algeria)

2012-12-15T23:59:59.000Z

366

A.N. Witt, B.T. Draine, & G.C. Clayton Dust in Protoplanetary Disks  

E-Print Network (OSTI)

Abstract. We critically examine the best lines of evidence for grain growth in protoplanetary disks, based on modelling of observed spectral energy distributions and images of T Tauri and Herbig Ae stars. The data are consistent with millimeter-sized grains near disk midplanes, and micron-sized grains near disk surfaces. We review three channels by which grains can grow, including direct condensation from the vapor phase, grain-grain collisional sticking, and gravitational instability. The utility of dust in identifying as yet unseen extrasolar planets is highlighted. 1.

E. I. Chiang

2003-01-01T23:59:59.000Z

367

Process for reducing aqueous nitrate to ammonia  

DOE Patents (OSTI)

Powdered aluminum is added to a nitrate-containing alkaline, aqueous solution to reduce the nitrate and/or nitrite to ammonia and co-produce a sinterable ceramic product.

Mattus, Alfred J. (Oak Ridge, TN)

1993-01-01T23:59:59.000Z

368

Process for reducing aqueous nitrate to ammonia  

DOE Patents (OSTI)

Powdered aluminum is added to a nitrate-containing alkaline, aqueous solution to reduce the nitrate and/or nitrite to ammonia and co-produce a sinterable ceramic product. 3 figures.

Mattus, A.J.

1993-11-30T23:59:59.000Z

369

Reducing the Energy Consumption of Networked Devices  

NLE Websites -- All DOE Office Websites (Extended Search)

Reducing the Energy Consumption of Networked Devices Speaker(s): Ken Christensen Date: July 19, 2005 - 12:00pm Location: 90-4133 When Personal Computers are networked, energy...

370

Reoxidation of Bioreduced Uranium Under Reducing Conditions  

E-Print Network (OSTI)

Microbial reduction of uranium. Nature 350, 413-416 (1991).C. Enzymatic iron and uranium reduction by sulfate-reducingS. Reduction of hexavalent uranium from organic complexes by

2005-01-01T23:59:59.000Z

371

On reduced relatives with genitive subjects  

E-Print Network (OSTI)

What is the place of relatives with genitive subjects in a typology of relative clauses? Are they full or reduced, headed or free relatives? Can they appear pre- and postnominally? Can they be head-internal relatives? Are ...

Krause, Cornelia (Cornelia Ann), 1972-

2001-01-01T23:59:59.000Z

372

Reducing the atmospheric impact of wet slaking  

SciTech Connect

Means of reducing the atmospheric emissions due to the wet slaking of coke are considered. One option, investigated here, is to remove residual active silt and organic compounds from the biologically purified wastewater sent for slaking, by coagulation and flocculation.

B.D. Zubitskii; G.V. Ushakov; B.G. Tryasunov; A.G.Ushakov [Kuznetsk Basin State Technical University, Kemerovo (Russian Federation)

2009-05-15T23:59:59.000Z

373

Reducing mode circulating fluid bed combustion  

DOE Patents (OSTI)

A method for combustion of sulfur-containing fuel in a circulating fluid bed combustion system wherein the fuel is burned in a primary combustion zone under reducing conditions and sulfur captured as alkaline sulfide. The reducing gas formed is oxidized to combustion gas which is then separated from solids containing alkaline sulfide. The separated solids are then oxidized and recycled to the primary combustion zone.

Lin, Yung-Yi (Katy, TX); Sadhukhan, Pasupati (Katy, TX); Fraley, Lowell D. (Sugarland, TX); Hsiao, Keh-Hsien (Houston, TX)

1986-01-01T23:59:59.000Z

374

Complete Reducibility in Euclidean Twin Buildings  

E-Print Network (OSTI)

Completely reducible subcomplexes of spherical buildings was defined by J.P. Serre and are used in studying subgroups of reductive algebraic groups. We begin the study of completely reducible subcomplexes of twin buildings and how they may be used to study subgroups of algebraic groups over a ring of Laurent polynomials and Kac-Moody groups by looking at the Euclidean twin building case.

Dawson, Denise K

2011-01-01T23:59:59.000Z

375

Potential for Reducing Consumption Through Distribution Efficiency  

Science Conference Proceedings (OSTI)

In 2007, EPRI released a Prism analysis, providing a technically and economically feasible roadmap for the electricity sector to reduce its greenhouse gas emissions. This approach has been extended to evaluate the utility distribution sector and opportunities to improve efficiency and reduce consumption. Possible improvements in efficiency are estimated by improvement category, including use of more efficient transformers and better reactive power management. Voltage optimization is a significant option ...

2010-12-31T23:59:59.000Z

376

The Global Gas and Dust budge of the Large Magellanic Cloud --- Importance of Asymptotic Giant Branch stars  

E-Print Network (OSTI)

It is still an unresolved problem how much AGB stars can contribute to the overall gas and dust enrichment processes in the interstellar medium within galaxies. We start tackling this problem, by using our test case observational data from the Large Magellanic Cloud (LMC), from which we obtain the global gas and dust budget. The photometric data from the LMC is obtained with the Spitzer Space Telescope. We established an infrared colour classification scheme to select AGB stars, which are based on spectroscopically identified AGB stars. We further confirm a correlation between the Spitzer colour and mass-loss rate, which leads to a measurement of the total mass-loss rate from the entire AGB population in the LMC. Indeed, AGB stars are an important gas and dust source.

Matsuura, M

2010-01-01T23:59:59.000Z

377

Formulation of Non-steady-state Dust Formation Process in Astrophysical Environments  

E-Print Network (OSTI)

The non-steady-state formation of small clusters and the growth of grains accompanied by chemical reactions are formulated under the consideration that the collision of key gas species (key molecule) controls the kinetics of dust formation process. The formula allows us to evaluate the size distribution and condensation efficiency of dust formed in astrophysical environments. We apply the formulation to the formation of C and MgSiO3 grains in the ejecta of supernovae, as an example, to investigate how the non-steady effect influences the formation process, condensation efficiency f_{con}, and average radius a_{ave} of newly formed grains in comparison with the results calculated with the steady-state nucleation rate. We show that the steady-state nucleation rate is a good approximation if the collision timescale of key molecule tau_{coll} is much smaller than the timescale tau_{sat} with which the supersaturation ratio increases; otherwise the effect of the non-steady state becomes remarkable, leading to a lo...

Nozawa, Takaya

2013-01-01T23:59:59.000Z

378

Multi-spectral Observations of Lunar Occultations: I. Resolving The Dust Shell Around AFGL 5440  

E-Print Network (OSTI)

We present observations and modeling of a lunar occultation of the dust-enshrouded carbon star AFGL 5440. The observations were made over a continuous range of wavelengths from 1 - 4um with a high-speed spectrophotometer designed expressly for this purpose. We find that the occultation fringes cannot be fit by any single-size model. We use the DUSTY radiative transfer code to model a circumstellar shell and fit both the observed occultation light curves and the spectral energy distribution described in the literature. We find a strong constraint on the inner radius of the dust shell, Tmax = 950 K +/- 50K, and optical depth at 5um of 0.5 +/- 0.1. The observations are best fit by models with a density gradient of r^-2 or the gradient derived by Ivezic & Elitzur for a radiatively driven hydrodynamic outflow. Our models cannot fit the observed IRAS 60um flux without assuming a substantial abundance of graphite or by assuming a substantially higher mass-loss rate in the past.

Paul M. Harvey; Andrew Oldag

2007-04-02T23:59:59.000Z

379

Multi-spectral Observations of Lunar Occultations: I. Resolving The Dust Shell Around AFGL 5440  

E-Print Network (OSTI)

We present observations and modeling of a lunar occultation of the dust-enshrouded carbon star AFGL 5440. The observations were made over a continuous range of wavelengths from 1 - 4um with a high-speed spectrophotometer designed expressly for this purpose. We find that the occultation fringes cannot be fit by any single-size model. We use the DUSTY radiative transfer code to model a circumstellar shell and fit both the observed occultation light curves and the spectral energy distribution described in the literature. We find a strong constraint on the inner radius of the dust shell, Tmax = 950 K +/- 50K, and optical depth at 5um of 0.5 +/- 0.1. The observations are best fit by models with a density gradient of r^-2 or the gradient derived by Ivezic & Elitzur for a radiatively driven hydrodynamic outflow. Our models cannot fit the observed IRAS 60um flux without assuming a substantial abundance of graphite or by assuming a substantially higher mass-loss rate in the past.

Harvey, Paul M

2007-01-01T23:59:59.000Z

380

Hydrometallurgical process for recovering iron sulfate and zinc sulfate from baghouse dust  

DOE Patents (OSTI)

A process for recovering zinc-rich and iron-rich fractions from the baghouse dust that is generated in various metallurgical operations, especially in steel-making and other iron-making plants, comprises the steps of leaching the dust by hot concentrated sulfuric acid so as to generate dissolved zinc sulfate and a precipitate of iron sulfate, separating the precipitate from the acid by filtration and washing with a volatile liquid, such as methanol or acetone, and collecting the filtered acid and the washings into a filtrate fraction. The volatile liquid may be recovered by distillation, and the zinc may be removed from the filtrate by alternative methods, one of which involves addition of a sufficient amount of water to precipitate hydrated zinc sulfate at 10 C, separation of the precipitate from sulfuric acid by filtration, and evaporation of water to regenerate concentrated sulfuric acid. The recovery of iron may also be effected in alternative ways, one of which involves roasting the ferric sulfate to yield ferric oxide and sulfur trioxide, which can be reconverted to concentrated sulfuric acid by hydration. The overall process should not generate any significant waste stream. 1 figure.

Zaromb, S.; Lawson, D.B.

1994-02-15T23:59:59.000Z

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Water formation on bare grains: When the chemistry on dust impacts interstellar gas  

E-Print Network (OSTI)

Context. Water together with O2 are important gas phase ingredients to cool dense gas in order to form stars. On dust grains, H2 O is an important constituent of the icy mantle in which a complex chemistry is taking place, as revealed by hot core observations. The formation of water can occur on dust grain surfaces, and can impact gas phase composition. Aims. The formation of molecules such as OH, H2 O, HO2, H2 O2, as well as their deuterated forms and O2 and O3 is studied in order to assess how the chemistry varies in different astrophysical environments, and how the gas phase is affected by grain surface chemistry. Methods. We use Monte Carlo simulations to follow the formation of molecules on bare grains as well as the fraction of molecules released into the gas phase. We consider a surface reaction network, based on gas phase reactions, as well as UV photo-dissociation of the chemical species. Results. We show that grain surface chemistry has a strong impact on gas phase chemistry, and that this chemistry...

Cazaux, S; Marseille, M; Spaans, M; Caselli, P

2010-01-01T23:59:59.000Z

382

Final Technical Report: Development of the DUSTRAN GIS-Based Complex Terrain Model for Atmospheric Dust Dispersion  

SciTech Connect

Activities at U.S. Department of Defense (DoD) training and testing ranges can be sources of dust in local and regional airsheds governed by air-quality regulations. The U.S. Department of Energy’s Pacific Northwest National Laboratory just completed a multi-year project to develop a fully tested and documented atmospheric dispersion modeling system (DUST TRANsport or DUSTRAN) to assist the DoD in addressing particulate air-quality issues at military training and testing ranges.

Allwine, K Jerry; Rutz, Frederick C.; Shaw, William J.; Rishel, Jeremy P.; Fritz, Brad G.; Chapman, Elaine G.; Hoopes, Bonnie L.; Seiple, Timothy E.

2007-05-01T23:59:59.000Z

383

Effects of Prior Precipitation and Source Area Characteristics on Threshold Wind Velocities for Blowing Dust Episodes, Sonoran Desert 1948–78  

Science Conference Proceedings (OSTI)

A better understanding of the effects of precipitation and source area on blowing dust in the Sonoran Desert has been sought through the study of 1190 dust episodes occurring during the 1948–78 time period at Blythe, California, and Yuma, ...

Troy Leon Holcombe; Trevor Ley; Dale A. Gillette

1997-09-01T23:59:59.000Z

384

Reducing Energy Usage in Extractive Distillation  

E-Print Network (OSTI)

Butadiene 1:3 is separated from other C4-hydrocarbons by extractive distillation in a sieve plate tower. Prior to the development work to be described, the pressure in the extraction tower was controlled at a fixed value. The tower pressure-boilup control loop did not behave satisfactorily in the presence of non-condensables which entered with the feed. The capacity of the flooded reflux drum condenser for the tower was limiting production during summer months. The tower pressure control loop was put on manual. The pressure was allowed to drop to its lowest attainable value for the existing conditions of boilup and condenser cooling capability. This manner of operation is known as floating pressure control. By taking advantage of the higher relative volatility at the lower tower pressure, energy usage was reduced and there was an increase in production capacity. The tower operation at a lower temperature reduced tower and reboiler fouling. Substantial savings have resulted from these improvements. The annual energy consumption has been reduced by 25% and maximum productive capacity is higher by 15%. The rate of tower and reboiler fouling has not been fully quantified but is greatly reduced. A more stable tower operation has also contributed to higher productivity and reduced energy usage. Venting of non-condensables does not affect tower stability and the operators have adapted well to the new control strategy.

Saxena, A. C.; Bhandari, V. A.

1985-05-01T23:59:59.000Z

385

Influence by small dispersive coal dust particles of different fractional consistence on characteristics of iodine air filter at nuclear power plant  

E-Print Network (OSTI)

The main purpose of research is to determine the influence by the small dispersive coal dust particles of the different fractional consistence on the technical characteristics of the vertical iodine air filter at nuclear power plant. The research on the transport properties of the small dispersive coal dust particles in the granular filtering medium of absorber in the vertical iodine air filter is completed in the case, when the modeled aerodynamic conditions are similar to the real aerodynamic conditions. It is shown that the appearance of the different fractional consistence of small dispersive coal dust particles with the decreasing dimensions down to the micro and nano sizes at the action of the air dust aerosol stream normally results in a significant change of distribution of the small dispersive coal dust particles masses in the granular filtering medium of an absorber in the vertical iodine air filter, changing the vertical iodine air filter aerodynamic characteristics. The precise characterization of...

Neklyudov, I M; Fedorova, L I; Poltinin, P Ya

2013-01-01T23:59:59.000Z

386

Unconventional Groundwater System Proves Effective in Reducing  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Unconventional Groundwater System Proves Effective in Reducing Unconventional Groundwater System Proves Effective in Reducing Contamination at West Valley Demonstration Project Unconventional Groundwater System Proves Effective in Reducing Contamination at West Valley Demonstration Project July 22, 2013 - 12:00pm Addthis In the two years prior to the operation of the permeable treatment wall, pictured here, WVDP conducted extensive engineering and planning to ensure it would effectively remove strontium-90. In the two years prior to the operation of the permeable treatment wall, pictured here, WVDP conducted extensive engineering and planning to ensure it would effectively remove strontium-90. This 2009 photo shows a trenching machine, which is capable of cutting a continuous trench up to 30 feet deep and 3 feet wide. The machine was used in a pilot study to evaluate the effectiveness of zeolite placement as the trench was dug. This ensured a consistent depth and width for the zeolite placement along the entire length of the permeable treatment wall.

387

Definition: Reduced Sustained Outages | Open Energy Information  

Open Energy Info (EERE)

Outages Outages Jump to: navigation, search Dictionary.png Reduced Sustained Outages A sustained outage is one lasting >5 minutes, excluding major outages and wide-scale outages. The monetary benefit of reducing sustained outages is based on the value of service (VOS) of each customer class. The VOS parameter represents the total cost of a power outage per MWh. This cost includes the value of unserved energy, lost productivity, collateral damage, administrative costs, the value of penalties and performance-based rates. Functions that lead to this benefit can reduce the likelihood that there will be an outage, allow the system to be reconfigured on the fly to help restore service to as many customers as possible, enable a quicker response in the restoration effort, or mitigate the impact of an outage

388

Reduce Threshold for Toplit Daylighting Area  

NLE Websites -- All DOE Office Websites (Extended Search)

Supporting analysis for proposed Supporting analysis for proposed changes to the commercial provisions of the 2012 IECC: Reduce Threshold for Toplit Daylighting Area R Hart R Athalye Pacific Northwest National Laboratory December 2012 2 Proposal Description This proposal modifies Section C402.3.2 of the 2012 IECC for the 2015 version. It reduces the area threshold for skylight daylit zones from 10,000 square feet to 2,000 square feet. It maintains 15 foot ceiling height requirement and the exception for climate zones 6 through 8. Energy Impact Based on average national energy prices 1 of $0.99 per therm and $0.1032 per kWh, the net savings are calculated with EnergyPlus(tm) 2 from whole building energy savings that result from reduced lighting, and depending on climate zone, increased or decreased heating and cooling.

389

Definition: Reduced Momentary Outages | Open Energy Information  

Open Energy Info (EERE)

Momentary Outages Momentary Outages Jump to: navigation, search Dictionary.png Reduced Momentary Outages By locating faults more accurately or adding electricity storage, momentary outages could be reduced or eliminated. Moreover, fewer customers on the same or adjacent distribution feeders would experience the momentary interruptions associated with reclosing. Momentary outages last <5 min in duration. The benefit to consumers is based on the value of service.[1] Related Terms electricity storage technologies, electricity generation, smart grid References ↑ SmartGrid.gov 'Description of Benefits' An in LikeLike UnlikeLike You like this.Sign Up to see what your friends like. line Glossary Definition Retrieved from "http://en.openei.org/w/index.php?title=Definition:Reduced_Momentary_Outages&oldid=493094

390

Alternatives for reducing hot-water bills  

DOE Green Energy (OSTI)

A two stage approach to reducing residential water heating bills is described. In Stage I, simple conservation measures were included to reduce the daily hot water energy consumption and the energy losses from the water tank. Once these savings are achieved, Stage II considers more costly options for further reducing the water heating bill. Four alternatives are considered in Stage II: gas water heaters; solar water heaters (two types); heat pump water heaters; and heat recovery from a heat pump or air conditioner. To account for variations within the MASEC region, information on water heating in Rapid City, Minneapolis, Chicago, Detroit, and Kansas City is presented in detail. Information on geography, major population centers, fuel prices, climate, and state solar incentives is covered. (MCW)

Bennington, G.E.; Spewak, P.C.

1981-06-01T23:59:59.000Z

391

A reduced Blade-Vortex Interaction rotor  

E-Print Network (OSTI)

This research work aims at mapping the BVI azimuthal locations using a model rotor. A model rotor was first developed. An experimental investigation was then carried out to determine the possible BVI locations. The results of the mapping are presented. A qualitative discussion about the nature of the pressure signals obtained is presented. An attempt is made to reduce the BVI strengths using an innovative blade tip device. The results for the rotor with the tip device installed are compared with the results obtained without the tip device installed. The comparisons show the tip device to be fairly effective in reducing the strength of the BVI.

Mani, Somnath

1996-01-01T23:59:59.000Z

392

Reducing the Energy Usage of Office Applications  

E-Print Network (OSTI)

In this paper, we demonstrate how component-based middleware can reduce the energy usage of closed-source applications. We rst describe how the Puppeteer system exploits well-dened interfaces exported by applications to modify their behavior. We then present a detailed study of the energy usage of Microsoft's PowerPoint application and show that adaptive policies can reduce energy expenditure by 49% in some instances. In addition, we use the results of the study to provide general advice to developers of applications and middleware that will enable them to create more energy-ecient software. 1

Jason Flinn; Eyal De Lara; M. Satyanarayanan; Dan S. Wallach; Willy Zwaenepoel; Willy

2001-01-01T23:59:59.000Z

393

Reducing branch divergence in GPU programs  

Science Conference Proceedings (OSTI)

Branch divergence has a significant impact on the performance of GPU programs. We propose two novel software-based optimizations, called iteration delaying and branch distribution that aim to reduce branch divergence. Iteration delaying ... Keywords: GPGPU, branch divergence, data parallel programming

Tianyi David Han; Tarek S. Abdelrahman

2011-03-01T23:59:59.000Z

394

Path specialization: reducing phased execution overheads  

Science Conference Proceedings (OSTI)

As garbage collected languages become widely used, the quest for reducing collection overheads becomes essential. In this paper, we propose a compiler optimization called path specialization that shrinks the cost of memory barriers for a wide ... Keywords: c#, garbage collection, memory management, read barriers, write barriers

Filip Pizlo; Erez Petrank; Bjarne Steensgaard

2008-06-01T23:59:59.000Z

395

Reduced No.sub.x combustion method  

DOE Patents (OSTI)

A combustion method enabling reduced NO.sub.x formation wherein fuel and oxidant are separately injected into a combustion zone in a defined velocity relation, combustion gases are aspirated into the oxidant stream prior to intermixture with the fuel, and the fuel is maintained free from contact with oxygen until the intermixture.

Delano, Mark A. (Briarcliff Manor, NY)

1991-01-01T23:59:59.000Z

396

Coal Biomodification to Reduce Mercury Emissions  

NLE Websites -- All DOE Office Websites (Extended Search)

Road P.O. Box 880 Morgantown, WV 26507-0880 304-285-4132 heino.beckert@netl.doe.gov Coal BiomodifiCation to ReduCe meRCuRy emissions Description In partnership with a number of...

397

Identify the Problem: Reduce Waste By  

E-Print Network (OSTI)

Identify the Problem: Reduce Waste By Banning Plastic Bag Use Define Goal: Is the ban the most The 2008 EPA report asserts that while paper waste has remained relatively constant at approximately 31%, plastic waste has been rising from 0.4% in 1960 to the present value at 12%a. San Francisco sets the goal

Iglesia, Enrique

398

5. ASSESSMENT RECOMMENDATIONS Reduce Discharge Pressure  

E-Print Network (OSTI)

will depend on its design and actual operating conditions. A detailed analysis by a refrigeration engineer the minimum condensing temperatures on your warehouse refrigeration systems from 110°F to 60°F. In order to reduce condensing temperature, we recommend installing a Liquid Refrigerant Pump (LRP) downstream from

Tullos, Desiree

399

Reducing code size through address register assignment  

Science Conference Proceedings (OSTI)

In DSP processors, minimizing the amount of address calculations is critical for reducing code size and improving performance, since studies of programs have shown that instructions that manipulate address registers constitute a significant portion of ... Keywords: DSP, Software compilation, address registers, register assignment

G. Chen; M. Kandemir; M. J. Irwin; J. Ramanujam

2006-02-01T23:59:59.000Z

400

Reduced-precision redundancy on FPGAs  

Science Conference Proceedings (OSTI)

Reduced-precision redundancy (RPR) has been shown to be a viable alternative to triple modular redundancy (TMR) for digital circuits. This paper builds on previous research by offering a detailed analysis of the implementation of RPR on FPGAs to improve ...

Brian Pratt; Megan Fuller; Michael Wirthlin

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Reducing memory sharing overheads in distributed JVMs  

Science Conference Proceedings (OSTI)

Distributed JVM systems by supporting Java’s shared-memory model enable concurrent Java applications to run transparently on clusters of computers. Aiming to reduce the overheads associated to memory coherence enforcement mechanisms required in ... Keywords: JVM, Java, cluster computing, concurrent Java applications, distributed shared memory, high-performance computing

Marcelo Lobosco; Orlando Loques; Claudio L. de Amorim

2005-09-01T23:59:59.000Z

402

Investigation of the optical and cloud forming properties of pollution, biomass burning, and mineral dust aerosols  

E-Print Network (OSTI)

This dissertation describes the use of measured aerosol size distributions and size-resolved hygroscopic growth to examine the physical and chemical properties of several particle classes. The primary objective of this work was to investigate the optical and cloud forming properties of a range of ambient aerosol types measured in a number of different locations. The tool used for most of these analyses is a differential mobility analyzer / tandem differential mobility analyzer (DMA / TDMA) system developed in our research group. To collect the data described in two of the chapters of this dissertation, an aircraft-based version of the DMA / TDMA was deployed to Japan and California. The data described in two other chapters were conveniently collected during a period when the aerosol of interest came to us. The unique aspect of this analysis is the use of these data to isolate the size distributions of distinct aerosol types in order to quantify their optical and cloud forming properties. I used collected data during the Asian Aerosol Characterization Experiment (ACE-Asia) to examine the composition and homogeneity of a complex aerosol generated in the deserts and urban regions of China and other Asian countries. An aircraft-based TDMA was used for the first time during this campaign to examine the size-resolved hygroscopic properties of the aerosol. The Asian Dust Above Monterey (ADAM-2003) study was designed both to evaluate the degree to which models can predict the long-range transport of Asian dust, and to examine the physical and optical properties of that aged dust upon reaching the California coast. Aerosol size distributions and hygroscopic growth were measured in College Station, Texas to investigate the cloud nucleating and optical properties of a biomass burning aerosol generated from fires on the Yucatan Peninsula. Measured aerosol size distributions and size-resolved hygroscopicity and volatility were used to infer critical supersaturation distributions of the distinct particle types that were observed during this period. The predicted cloud condensation nuclei concentrations were used in a cloud model to determine the impact of the different aerosol types on the expected cloud droplet concentration. RH-dependent aerosol extinction coefficients were also calculated.

Lee, Yong Seob

2003-05-01T23:59:59.000Z

403

Vertical distribution and radiative effects of mineral dust and biomass burning aerosol over West Africa during DABEX  

SciTech Connect

This paper presents measurements of the vertical distribution of aerosol extinction coefficient over West Africa, during the Dust and Biomass burning aerosol Experiment (DABEX) / African Monsoon Multidisciplinary Analysis dry season Special Observing period zero (AMMA-SOP0). In situ aircraft measurements from the UK FAAM aircraft are compared with two ground based lidars (POLIS and ARM MPL) and an airborne lidar on an ultra-light aircraft. In general mineral dust was observed at low altitudes (up to 2km) and a mixture of biomass burning aerosol and dust was observed at altitudes of 2-5km. The study exposes difficulties associated with spatial and temporal variability when inter-comparing aircraft and ground measurements. Averaging over many profiles provided a better means of assessing consistent errors and biases associated with in situ sampling instruments and retrievals of lidar ratios. Shortwave radiative transfer calculations and a 3-year simulation with the HadGEM2-A climate model show that the radiative effect of biomass burning aerosol is somewhat sensitive to the vertical distribution of aerosol. Results show a 15% increase in absorption of solar radiation by elevated biomass burning aerosol when the observed low-level dust layer is included as part of the background atmospheric state in the model. This illustrates that the radiative forcing of anthropogenic absorbing aerosol is sensitive to the treatment of other aerosol species and that care is needed in simulating natural aerosols assumed to exist in the pre-industrial, or natural state of the atmosphere.

Johnson, Ben; Heese, B.; McFarlane, Sally A.; Chazette, P.; Jones, A.; Bellouin, N.

2008-09-12T23:59:59.000Z

404

The Potential of Infrared Satellite Data for the Retrieval of Saharan-Dust Optical Depth over Africa  

Science Conference Proceedings (OSTI)

Optical depth of Saharan dust derived from photometric measurements made during the dry season at a Sahelian site (Niamey, Republic of Niger) is compared with METEOSAT-2 radiance in the 10.5–12.5 ?m channel for different times of the daily cycle. ...

M. Legrand; J. J. Bertrand; M. Desbois; L. Menenger; Y. Fouquart

1989-04-01T23:59:59.000Z

405

Lead Speciation in House Dust from Canadian Urban Homes Using EXAFS Micro-XRF and Micro-XRD  

SciTech Connect

X-ray absorption fine-structure (XAFS) spectroscopy, micro-X-ray fluorescence ({mu}XRF), and micro-X-ray diffraction ({mu}XRD) were used to determine the speciation of Pb in house dust samples from four Canadian urban homes having elevated Pb concentrations (>1000 mg Pb kg{sup -1}). Linear combination fitting of the XAFS data, supported by {mu}XRF and {mu}XRD, shows that Pb is complexed in a variety of molecular environments, associated with both the inorganic and organic fractions of the dust samples. The inorganic species of lead identified were as follows: Pb metal, Pb carbonate, Pb hydroxyl carbonate, Pb oxide, and Pb adsorbed to iron oxyhydroxides. Pb carbonate and/or Pb hydroxyl carbonate occurred in all four dust samples and accounted for 28 to 75% of total Pb. Pb citrate and Pb bound to humate were the organic species identified. The results of this study demonstrate the ability of XAFS to identify Pb speciation in house dust and show the potential to identify Pb sources from new homes versus older homes. Understanding Pb speciation and how it influences bioaccessibility is important for human health risk assessment and risk management decisions which aim to improve indoor environmental health.

L MacLean; S Beauchemin; P Rasmussen

2011-12-31T23:59:59.000Z

406

H2O Maser Emission in Circumstellar Envelopes around AGB Stars: Physical Conditions in Gas-Dust Clouds  

E-Print Network (OSTI)

The pumping of 22.2-GHz H$_2$O masers in the circumstellar envelopes of asymptotic giant branch stars has been simulated numerically. The physical parameters adopted in the calculations correspond to those of the circumstellar envelope around IK Tau. The one-dimensional plane-parallel structure of the gas-dust cloud is considered. The statistical equilibrium equations for the H$_2$O level populations and the thermal balance equations for the gas-dust cloud are solved self-consistently. The calculations take into account 410 rotational levels belonging to the five lowest vibrational levels of H$_2$O. The stellar radiation field is shown to play an important role in the thermal balance of the gas-dust cloud due to the absorption of emission in rotational-vibrational H$_2$O lines. The dependence of the gain in the 22.2-GHz maser line on the gas density and H$_2$O number density in the gas-dust cloud is investigated. Gas densities close to the mean density of the stellar wind, 10$^7-10^8$ cm$^{-3}$, and a high re...

Nesterenok, Aleksandr

2013-01-01T23:59:59.000Z

407

North African dust and its relation to paleoclimate recorded in a sediment core from Northwest Providence Channel, Bahamas  

SciTech Connect

Studies of the vertical distribution of insoluble residue in an 11.7 meter core recovered from 665m water depth within Northwest Providence Channel, Bahamas demonstrate cyclic fluctuations in the content and mineralogy of the insoluble residue. The insoluble residue consists of chlorite, montmorillonite, illite and kaolinite with alternating layers enriched in chlorite or montmorillonite. These fluctuations in the character of insoluble residue correspond to fluctuations of the record of oxygen isotopes and foraminiferal assemblages (paleoclimate) and of carbonate mineralogy (sea level). During glacial periods, insoluble residue concentration is high, dolomite is present and quartz, plagioclase and chlorite concentrations increase. During interglacial periods, insoluble residue concentration is low, dolomite is absent and quartz, plagioclase and chlorite concentration decreases while montmorillonite concentration increases. The source of the insoluble residue is dust derived from North Africa and transported by the Saharan Air Layer coupled with the Northeast Trades. During glacial periods, the source of the dust is the dolomite-rich southern North Africa region. This shift of the dust source suggests that the trade winds transporting the dust during glacial periods also shifted southward or expanded or both.

Eaton, M.R.; Boardman, M.R.

1985-01-01T23:59:59.000Z

408

Collision probabilities of migrating small bodies and dust particles with planets  

E-Print Network (OSTI)

Probabilities of collisions of migrating small bodies and dust particles produced by these bodies with planets were studied. Various Jupiter-family comets, Halley-type comets, long-period comets, trans-Neptunian objects, and asteroids were considered. The total probability of collisions of any considered body or particle with all planets did not exceed 0.2. The amount of water delivered from outside of Jupiter's orbit to the Earth during the formation of the giant planets could exceed the amount of water in Earth's oceans. The ratio of the mass of water delivered to a planet by Jupiter-family comets or Halley-type comets to the mass of the planet can be greater for Mars, Venus, and Mercury, than that for Earth.

Ipatov, S I

2009-01-01T23:59:59.000Z

409

Enhanced production of HD and D_2 molecules on small dust grains in diffuse clouds  

E-Print Network (OSTI)

Motivated by recent observations of deuterated molecules in the interstellar medium, we examine the production of HD and D$_2$ molecules on dust grain surfaces. A mechanism for the enhanced production of these deuterated molecules is studied. This mechanism applies on grain surfaces on which D atoms stick more strongly than H atoms, under conditions of low flux and within a suitable range of temperatures. It is shown that under these conditions the production rates of HD and D$_2$ are greatly enhanced (vs. the H$_2$ production rate) compared with the expected rates based on the adsorption of gas-phase atomic abundances of D and H. The enhancement in the formation rate of HD is comparable with the enhancement due to gas-phase ion-molecule reactions in diffuse clouds.

Azi Lipshtat; Ofer Biham; Eric Herbst

2003-11-23T23:59:59.000Z

410

Formation of molecular hydrogen on analogues of interstellar dust grains: experiments and modelling  

E-Print Network (OSTI)

Molecular hydrogen has an important role in the early stages of star formation as well as in the production of many other molecules that have been detected in the interstellar medium. In this review we show that it is now possible to study the formation of molecular hydrogen in simulated astrophysical environments. Since the formation of molecular hydrogen is believed to take place on dust grains, we show that surface science techniques such as thermal desorption and time-of-flight can be used to measure the recombination efficiency, the kinetics of reaction and the dynamics of desorption. The analysis of the experimental results using rate equations gives useful insight on the mechanisms of reaction and yields values of parameters that are used in theoretical models of interstellar cloud chemistry.

Gianfranco Vidali; Joe Roser; Giulio Manico; Valerio Pirronello; Hagai B. Perets; Ofer Biham

2005-04-25T23:59:59.000Z

411

Observation of the spatial growth of self-excited dust-density waves  

SciTech Connect

The growth of a naturally occurring dust-density wave (DDW) is experimentally observed using high-speed imaging. This low frequency wave ({approx}25 Hz) grows in amplitude as it propagates downward through a dusty plasma. The wave's linear growth rate -k{sub i} is measured using a phase-sensitive analysis method. For the conditions studied here, the growth rate increases as gas pressure decreases. At a critical gas pressure, which is observed, a balance between an ion-flow instability and dissipation by neutral gas drag determines a threshold for wave propagation. A linear dispersion relation is derived, taking into account the effects of strong-coupling, to compare to the experiment.

Flanagan, T. M.; Goree, J. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States)

2010-12-15T23:59:59.000Z

412

Dispersion relations of externally and thermally excited dust lattice modes in 2D complex plasma crystals  

SciTech Connect

The dispersion relations of the externally and thermally (naturally) excited dust lattice modes (both longitudinal and transverse) in two-dimensional Debye-Yukawa complex plasma crystals are investigated. The dispersion relations are calculated numerically by taking the neutral gas damping effects into account and the numerical results are in agreement with the experimental data given by Nunomura et al.[Phys. Rev. E 65, 066402 (2002)]. It is found that for the mode excited by an external disturbance with a real frequency, the dispersion properties are changed at a critical frequency near where the group velocity of the mode goes to zero. Therefore, the high frequency branch with negative dispersion cannot be reached. In contrast, for the thermally excited mode, the dispersion curve can extend all the way to the negative dispersion region, while a 'cut-off' wave number exists at the long wavelength end of the dispersion in the transverse mode.

Yang Xuefeng; Cui Jian; Zhang Yuan [School of Mathematical Sciences, Dalian University of Technology, Dalian 116024 (China); Liu Yue [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

2012-07-15T23:59:59.000Z

413

Maximizing Ion Current by Space Charge Neutralization using Negative Ions and Dust Particles  

DOE Green Energy (OSTI)

Ion current extracted from an ion source (ion thruster) can be increased above the Child-Langmuir limit if the ion space charge is neutralized. Similarly, the limiting kinetic energy density of the plasma flow in a Hall thruster might be exceeded if additional mechanisms of space charge neutralization are introduced. Space charge neutralization with high-mass negative ions or negatively charged dust particles seems, in principle, promising for the development of a high current or high energy density source of positive light ions. Several space charge neutralization schemes that employ heavy negatively charged particles are considered. It is shown that the proposed neutralization schemes can lead, at best, only to a moderate but nonetheless possibly important increase of the ion current in the ion thruster and the thrust density in the Hall thruster.

A. Smirnov; Y. Raitses; N.J. Fisch

2005-01-25T23:59:59.000Z

414

Cooling flows, central galaxy--cluster alignments, X-ray absorption and dust  

E-Print Network (OSTI)

We present the analysis of pointed ROSAT PSPC observations of five of the most luminous, intermediate redshift ($0.1 cooling flows. The alignment between CCGs and their host clusters has been investigated. For those clusters with cooling flows, the position angles of the X-ray emission from the clusters and the optical emission from the CCGs agrees within 5 degrees. For the one probable non-cooling flow cluster in the sample, Abell 2208, the alignment is significantly poorer. We examine the evidence for intrinsic X-ray absorption in the clusters. The X-ray spectra for Abell 1068 and Abell 1664 show that the cooling flows in these clusters are intrinsically absorbed by equivalent hydrogen column densities $\\geq 10^{21} atom cm$^{-2}$. The optical spectra of the CCGs in these clusters exhibit substantial intrinsic reddening, at levels consistent with the X-ray absorption results if standard dust to gas ratios are assumed.

S. W. Allen; A. C. Fabian; A. C. Edge; H. Bohringer; D. A. White

1995-03-28T23:59:59.000Z

415

FROM PLANETESIMALS TO DUST: LOW-GRAVITY EXPERIMENTS ON RECYCLING SOLIDS AT THE INNER EDGES OF PROTOPLANETARY DISKS  

SciTech Connect

Transporting solids of different sizes is an essential process in the evolution of protoplanetary disks and planet formation. Large solids are supposed to drift inward; high-temperature minerals found in comets are assumed to have been transported outward. From low-gravity experiments on parabolic flights, we studied the light-induced erosion of dusty bodies caused by a solid-state greenhouse effect and photophoresis within a dust bed's upper layers. The gravity levels studied were 0.16g, 0.38g, 1g, and 1.7g. The light flux during the experiments was 12 {+-} 2 kW m{sup -2} and the ambient pressure was 6 {+-} 0.9 mbar. Light-induced erosion is strongly gravity dependent, which is in agreement with a developed model. In particular for small dusty bodies ((sub)-planetesimals), efficient erosion is possible at the optically thin inner edges of protoplanetary disks. Light-induced erosion prevents significant parts of a larger body from moving too close to the host star and being subsequently accreted. The small dust produced continues to be subject to photophoresis and is partially transported upward and outward over the surface of the disk; the resulting small dust particles are observed over the disk's lifetime. The fraction of eroded dust participates in subsequent cycles of growth during planetesimal formation. Another fraction of dust might be collected by a body of planetary size if this body is already present close to the disk edge. Either way, light-induced erosion is an efficient recycling process in protoplanetary disks.

De Beule, Caroline; Kelling, Thorben; Wurm, Gerhard; Teiser, Jens; Jankowski, Tim, E-mail: caroline.de-beule@uni-due.de [Universitaet Duisburg-Essen, Fakultaet fuer Physik, Lotharstrasse 1, D-47057 Duisburg (Germany)] [Universitaet Duisburg-Essen, Fakultaet fuer Physik, Lotharstrasse 1, D-47057 Duisburg (Germany)

2013-01-20T23:59:59.000Z

416

Circumnuclear Dust in Nearby Active and Inactive Galaxies. II. Bars, Nuclear Spirals, and the Fueling of Active Galactic Nuclei  

E-Print Network (OSTI)

(Abridged) We present a detailed study of the relation between circumnuclear dust morphology, host galaxy properties, and nuclear activity in nearby galaxies. We use our sample of 123 nearby galaxies with visible--near-infrared colormaps from the Hubble Space Telescope to create well-matched, "paired" samples of 28 active and 28 inactive galaxies, as well as 19 barred and 19 unbarred galaxies, that have the same host galaxy properties. Comparison of the barred and unbarred galaxies shows that grand design nuclear dust spirals are only found in galaxies with a large-scale bar. Tightly wound nuclear dust spirals, in contrast, show a strong tendency to avoid galaxies with large-scale bars. Comparison of the AGN and inactive samples shows that nuclear dust spirals, which may trace shocks and angular momentum dissipation in the ISM, occur with comparable frequency in both active and inactive galaxies. The only difference between the active and inactive galaxies is that several inactive galaxies appear to completely lack dust structure in their circumnuclear region, while none of the AGN lack this structure. The comparable frequency of nuclear spirals in active and inactive galaxies, combined with previous work that finds no significant differences in the frequency of bars or interactions between well-matched active and inactive galaxies, suggests that no universal fueling mechanism for low-luminosity AGN operates at spatial scales greater than ~100 pc radius from the galactic nuclei. The similarities instead suggest that the lifetime of nuclear activity is less than the characteristic inflow time from these spatial scales. An order-of-magnitude estimate of this inflow time is the dynamical timescale. This sets an upper limit of several million years to the lifetime of an individual episode of nuclear activity.

Paul Martini; Michael W. Regan; John S. Mulchaey; Richard W. Pogge

2002-12-17T23:59:59.000Z

417

Reconciliation of Zero-Point and Dark Energies in a Friedman Dust Universe with Einstein's Lambda  

E-Print Network (OSTI)

In this paper, it is shown that the cosmological model that was introduced in a sequence of three earlier papers under the title, A Dust Universe Solution to the Dark Energy Problem, can be used to resolve the problem of the great mismatch of numerical values between dark energy from cosmology and zero point energy from quantum theory. It is shown that, if the zero point energies for the cosmic microwave background and for all the rest of the universe that is not cosmic microwave background are introduced into this model as two entities, their separate values appear within this theory in the form of a numerical difference. It is this difference that gives the numerical value for the zero point value of Einstein's dark energy density. Consequently, although the two zero point energies may be large, their difference can give the known small dark energy value from cosmology for dark energy density. Issues relating to interpretation, calculation and measurement associated with this result and an interpretation of dark energy as a measure of polarisation of the vacuum are discussed. In the first appendix to this paper, problems associated with the standard model of cosmology are solved by redefining temperature in the dust universe model. In the second appendix of this paper, an examination of the dark matter problem in relation to a general relativistic generalisation of Newton's inverse square law is undertaken. In the third appendix to this paper, the formalism is used to derive a formula that gives a possible value for the mass of the universe in terms of Newton's gravitation constant, Einstein's Lambda and the velocity of light. All three appendices have their own detailed abstracts.

James G. Gilson

2007-04-23T23:59:59.000Z

418

STAR FORMATION AND DISTRIBUTIONS OF GAS AND DUST IN THE CIRCINUS CLOUD  

Science Conference Proceedings (OSTI)

We present results of a study on the Circinus cloud based on {sup 13}CO (J = 1 - 0) data as well as visual to near-infrared (JHK{sub S}) extinction maps, to investigate the distributions of gas and dust around the cloud. The global {sup 13}CO distribution of the Circinus cloud is revealed for the first time, and the total molecular mass of the cloud is estimated to be 2.5 x 10{sup 4} M{sub sun} for the assumed distance 700 pc. Two massive clumps in the cloud, called Circinus-W and Circinus-E, have a mass of {approx}5 x 10{sup 3} M{sub sun}. These clumps are associated with a number of young stellar objects (YSOs) searched for in the literature, indicating that they are the most active star-forming sites in Circinus. All of the extinction maps show good agreement with the {sup 13}CO distribution. We derived the average N({sup 13}CO)/A{sub V} ratio in the Circinus cloud to be 1.25 x 10{sup 15} cm{sup -2} mag{sup -1} by comparing the extinction maps with the {sup 13}CO data. The extinction maps also allowed us to probe into the reddening law over the Circinus cloud. We found that there is a clear change in dust properties in the densest regions of Circinus-W and Circinus-E, possibly due to grain growth in the dense cloud interior. Among the YSOs found in the literature, we attempted to infer the ages and masses of the H{alpha} emission-line stars forming in the two clumps, and found that they are likely to be younger than 1 Myr, having a relatively small mass of {approx}<2 M{sub sun} at the zero-age main sequence.

Shimoikura, Tomomi; Dobashi, Kazuhito, E-mail: ikura@u-gakugei.ac.jp [Department of Astronomy and Earth Sciences, Tokyo Gakugei University, Koganei, Tokyo 184-8501 (Japan)

2011-04-10T23:59:59.000Z

419

Argonne Transportation - Engines - Reducing Heavy Vehicle Idling  

NLE Websites -- All DOE Office Websites (Extended Search)

Reducing Vehicle Idling Reducing Vehicle Idling What is Idling? graphic of a hypothetical no-idling sign When a vehicle's engine is on but the vehicle is not in motion, it is idling. Sitting at traffic lights, waiting in a running car to pick someone up, trucks idling while their drivers make deliveries or sleep during rest stops - these are all examples of idling. Why Care About Idling? Although many individual idling episodes are small, the cumulative impacts of idling are large! Consider that idling in the United States uses more than 6 billion gallons of fuel at a cost of more than $20 billion EACH year. Add to that the costs of maintenance related to the extra engine running time and the added emissions of particulates (PM10), nitrogen oxides (NOx), carbon monoxide (CO) and carbon dioxide (CO2) related to

420

Definition: Reduced Major Outages | Open Energy Information  

Open Energy Info (EERE)

Outages Outages Jump to: navigation, search Dictionary.png Reduced Major Outages A major outage is defined using the beta method, per IEEE Std 1366-2003 (IEEE Power Engineering Society 2004). The monetary benefit of reducing major outages is based on the VOS of each customer class. The VOS parameter represents the total cost of a power outage per MWh. This cost includes the value of unserved energy, lost productivity, collateral damage, the value of penalties and performance-based rates. Functions that lead to this benefit can mitigate major outages by allowing the system to be reconfigured on the fly to help restore service to as many customers as possible, enable a quicker response in the restoration effort, or mitigate the impact of an outage through islanding or alternative power supply.[1]

Note: This page contains sample records for the topic "reduce fugitive dust" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Take Steps to Reduce Heart Risks  

NLE Websites -- All DOE Office Websites (Extended Search)

Take Steps to Reduce Heart Risks Take Steps to Reduce Heart Risks February is American Heart Month -- a time to reflect on the sobering fact that heart disease remains the number one killer of both women and men in the United States. The good news is you have the power to protect and improve your heart health. NIH and other government agencies have been working to advance our understanding of heart disease so that people can live longer, healthier lives. Research has found that you can lower your risk for heart disease simply by adopting sensible health habits. To protect your heart, the first step is to learn your own personal risk factors for heart disease. Risk factors are conditions or habits that make you more likely to develop a disease. Risk factors can also increase the chances that an existing disease will get worse.

422

FETC Programs for Reducing Greenhouse Gas Emissions  

SciTech Connect

Mark Twain once quipped that everyone talks about the weather but no one does anything about it. With interest in global climate change on the rise, researchers in the fossil-energy sector are feeling the heat to provide new technology to permit continued use of fossil fuels but with reduced emissions of so-called `greenhouse gases.` Three important greenhouse gases, carbon dioxide, methane, and nitrous oxide, are released to the atmosphere in the course of recovering and combusting fossil fuels. Their importance for trapping radiation, called forcing, is in the order given. In this report, we briefly review how greenhouse gases cause forcing and why this has a warming effect on the Earth`s atmosphere. Then we discuss programs underway at FETC that are aimed at reducing emissions of methane and carbon dioxide.

Ruether, J.A.

1998-02-01T23:59:59.000Z

423

Quantum cryptographic system with reduced data loss  

DOE Patents (OSTI)

A secure method for distributing a random cryptographic key with reduced data loss. Traditional quantum key distribution systems employ similar probabilities for the different communication modes and thus reject at least half of the transmitted data. The invention substantially reduces the amount of discarded data (those that are encoded and decoded in different communication modes e.g. using different operators) in quantum key distribution without compromising security by using significantly different probabilities for the different communication modes. Data is separated into various sets according to the actual operators used in the encoding and decoding process and the error rate for each set is determined individually. The invention increases the key distribution rate of the BB84 key distribution scheme proposed by Bennett and Brassard in 1984. Using the invention, the key distribution rate increases with the number of quantum signals transmitted and can be doubled asymptotically.

Lo, Hoi-Kwong (1309, Low Block, Lei Moon House Ap Lei Chau Estate, Hong Kong, HK); Chau, Hoi Fung (Flat C, 42nd Floor, Tower 1, University Heights 23 Pokfield Road, Pokfulam, Hong Kong, HK)

1998-01-01T23:59:59.000Z

424

Cleaning optimization for reduced chemical usage  

SciTech Connect

The use of dilute SC-1 (NH40H:H202:H20) chemistry cleaning processes for particle removal from silicon surfaces has been investigated. Dilute chemistries can be highly effective, especially when high- frequency acoustic energy (megasonics) is applied. The high particle removal efficacy of the dilute chemistry processes presumably arises due to increased double layer effects caused by reduced ionic strength. Dilute chemistry SC- I solutions exhibit somewhat reduced efficacy for removal of certain light organics; however, when dilute SC-1 is used along with other pre-gate cleaning steps (e.g. HF, SC-2, and piranha), then the overall cleaning sequence is quite effective. In addition to providing robust cleaning processes, dilute chemistries also result in significantly lower chemical and rinse water usage. Waste water treatment requirements are also lessened when dilute chemistry cleaning solutions are employed.

Resnick, P.J.; Simonson, G.C.; Matlock, C.A.; Kelly, M.J.

1996-11-01T23:59:59.000Z

425

Quantum cryptographic system with reduced data loss  

DOE Patents (OSTI)

A secure method for distributing a random cryptographic key with reduced data loss is disclosed. Traditional quantum key distribution systems employ similar probabilities for the different communication modes and thus reject at least half of the transmitted data. The invention substantially reduces the amount of discarded data (those that are encoded and decoded in different communication modes e.g. using different operators) in quantum key distribution without compromising security by using significantly different probabilities for the different communication modes. Data is separated into various sets according to the actual operators used in the encoding and decoding process and the error rate for each set is determined individually. The invention increases the key distribution rate of the BB84 key distribution scheme proposed by Bennett and Brassard in 1984. Using the invention, the key distribution rate increases with the number of quantum signals transmitted and can be doubled asymptotically. 23 figs.

Lo, H.K.; Chau, H.F.

1998-03-24T23:59:59.000Z

426

Methods of reducing vehicle aerodynamic drag  

Science Conference Proceedings (OSTI)

A small scale model (length 1710 mm) of General Motor SUV was built and tested in the wind tunnel for expected wind conditions and road clearance. Two passive devices, rear screen which is plate behind the car and rear fairing where the end of the car is aerodynamically extended, were incorporated in the model and tested in the wind tunnel for different wind conditions. The conclusion is that rear screen could reduce drag up to 6.5% and rear fairing can reduce the drag by 26%. There were additional tests for front edging and rear vortex generators. The results for drag reduction were mixed. It should be noted that there are aesthetic and practical considerations that may allow only partial implementation of these or any drag reduction options.

Sirenko V.; Rohatgi U.

2012-07-08T23:59:59.000Z

427

Enhancing Thermal Conductivity and Reducing Friction  

NLE Websites -- All DOE Office Websites (Extended Search)

Laboratory currently has several projects underway to develop advanced fluids, films, coatings, and Laboratory currently has several projects underway to develop advanced fluids, films, coatings, and processes to improve thermal conductivity and reduce friction. These measures are helping to increase energy efficiency for next-generation transportation applications. Superhard and Slick Coating (SSC) Opportunity: Friction, wear, and lubrication strongly affect the energy efficiency, durability, and environmental compatibility of

428

Process for reducing radioactive contamination in phosphogypsum  

Science Conference Proceedings (OSTI)

A process of two crystallization stages for reducing radioactive contamination of phosphogypsum is disclosed. In the process anhydrite crystals are obtained through dehydration of the radiation containing phosphogypsum in strong sulfuric acid; a portion of the anhydrite crystals containing the radioactive contamination is converted to substantially radiation free gypsum by crystallizing out on a large solids concentration of radiation free gypsum seed crystals; and coarse radiation free gypsum crystals are separated from small anhydrite crystal relics containing substantially all of the radioactive contamination.

Gaynor, J.C.; Palmer, J.W.

1983-06-14T23:59:59.000Z

429

The Power to Reduce CO2 Emissions  

Science Conference Proceedings (OSTI)

In 2007 EPRI released its first Prism analysis [EPRI 2007], providing a technically and economically feasible roadmap for the electricity sector as it seeks to reduce greenhouse gas emissions. The Prism analysis provided a comprehensive assessment of potential CO2 reductions in key technology areas of the electricity sector. In 2009 EPRI, updated the analysis to reflect economic and technological changes that have the potential to affect projected emissions and the technologies to address them. The upda...

2010-12-07T23:59:59.000Z

430

Incentives for reducing emissions in Krakow  

SciTech Connect

This effort is identifying, specific incentives that may be used by Krakow city officials to encourage, residents to change the way they heat their homes and businesses in order to reduce pollution. This paper describes the incentives study for converting small coal or coke-fired boilers to gas in the Old Town area. A similar study looked at incentives for expanding the district heating system and future analyses will be performed for home stove options.

Uberman, R. [Polinvest Ltd., Krakow (Poland); Pierce, B. [Brookhaven National Lab., Upton, NY (United States); Lazecki, A. [Biuro Rozwoju Krakowa, Krakow (Poland)

1994-06-01T23:59:59.000Z

431

Reduce generating costs and eliminate brownouts  

Science Conference Proceedings (OSTI)

Improving the manoeuverability of a coal-fired plant to allow it to participate in primary frequency support will reduce generation cost and minimize brownouts. The challenge is to do so without compromising efficiency or emissions. This article describes an approach - activation of stored energy - that is cost-effective and applicable to both greenfield and brownfield installations. It requires a new control philosophy, plus the correct application of new level and flow measurement 'best practices'. 4 refs., 1 tab.

Nogaja, R.; Menezes, M. [Emerson Process Management (United States)

2007-06-15T23:59:59.000Z

432

Method for reducing coke oven carbonization pressure  

SciTech Connect

A method of reducing the carbonization pressure in the coking of coal is provided which comprises randomly dispersing flakes through the coal, said flakes formed of a material that does not pass through a plastic phase such as pressed sawdust wherein the flakes have a thickness of between about 1/8 '' and about 3/4 '' and a length and width of between about 1'' and about 5''.

Perch, M.

1981-04-28T23:59:59.000Z

433

Reducing Indoor Residential Exposures to Outdoor Pollutants  

NLE Websites -- All DOE Office Websites (Extended Search)

Reducing Indoor Residential Exposures to Outdoor Pollutants Reducing Indoor Residential Exposures to Outdoor Pollutants Title Reducing Indoor Residential Exposures to Outdoor Pollutants Publication Type Journal Article LBNL Report Number LBNL-51758 Year of Publication 2003 Authors Sherman, Max H., and Nance Matson Start Page Chapter Abstract Basic strategy for providing indoor air quality in residences is to dilute indoor sources with outdoor air. This strategy assumes that the outdoor air does not have pollutants at harmful levels or that the outdoor air is, at least, less polluted than the indoor air. When this is not the case, different strategies need to be employed to ensure adequate air quality in the indoor environment. These strategies include ventilation systems, filtration and other measures. These strategies can be used for several types of outdoor pollution, including smog, particulates and toxic air pollutants. This report reviews the impacts that typical outdoor air pollutants can have on the indoor environment and provides design and operational guidance for mitigating them. Poor quality air cannot be used for diluting indoor contaminants, but more generally it can become an indoor contaminant itself. This paper discusses strategies that use the building as protection against potentially hazardous outdoor pollutants, including widespread pollutants, accidental events, and potential attacks

434

Options for reducing carbon dioxide emissions  

Science Conference Proceedings (OSTI)

Improvements in energy efficiency can significantly reduce the annual growth in greenhouse gas emissions. Such improvements occur when energy intensity is reduced; no reduction in energy services is required. Using the concept of cost of conserved energy'' to develop conservation supply curves similar to resource supply curves, researchers consistently find that electricity and natural gas savings of nearly 50% of current consumption are possible for US buildings. Such reductions in energy consumption directly reduce emissions of greenhouse gases. To capture these savings, we must continue to develop energy-efficient technologies and strategies. This paper describes three recent energy-efficient technologies that benefited from energy conservation research and development (R D) funding: high-frequency ballasts, compact fluorescent lamps, and low-emissivity windows. Other advanced technologies and strategies of spectrally selective windows, superwindows, electrochromic windows, advanced insulation, low-flow showerheads, improved recessed lamp fixtures, whitening surfaces and planting urban trees, daylighting, and thermal energy storage are also discussed. 33 refs., 9 figs., 3 tabs.

Rosenfeld, A.H.; Price, L.

1991-08-01T23:59:59.000Z

435

Background dust emission following grassland fire: a snapshot across the particle-size spectrum highlights how high-resolution measurements enhance detection  

SciTech Connect

Dust emission rates vary temporally and with particle size. Many studies of dust emission focus on a particular temporal scale and the portion of the particle-size spectrum associated with a single instrument; fewer studies have assessed dust emission across the particle-size spectrum and associated temporal scales using multiple instruments. Particularly lacking are measurements following disturbances such as fire that are high-resolution and focused on finer particles - those with direct implications for human health and potential for long-distance biogeochemical transport - during less windy but more commonly occurring background conditions. We measured dust emissions in unburned and burned semiarid grassland using four different instruments spanning different combinations of temporal resolution and particle-size spectrum: Big Springs Number Eight (BSNE) and Sensit instruments for larger saltating particles, DustTrak instruments for smaller suspended particles, and Total Suspended Particulate (TSP) samplers for measuring the entire range of particle sizes. Unburned and burned sites differed in vegetation cover and aerodynamic roughness, yet surprisingly differences in dust emission rates were only detectable for saltation using BSNE and for smaller aerosols using DustTrak. Our results, surprising in the lack of consistently detected differences, indicate that high-resolution DustTrak measurements offered the greatest promise for detecting differences in background emission rates and that BSNE samplers, which integrate across height, were effective for longer intervals. More generally, our resul