Sample records for matter dust smoke

  1. Glaciation temperatures of convective clouds ingesting desert dust, air pollution and smoke from forest fires

    E-Print Network [OSTI]

    Daniel, Rosenfeld

    Glaciation temperatures of convective clouds ingesting desert dust, air pollution and smoke from observations show that desert dust and heavy air pollution over East Asia have similar ability to glaciate desert dust, air pollution and smoke from forest fires, Geophys. Res. Lett., 38, L21804, doi:10

  2. Dark energy and dust matter phases from an exact $f(R)$-cosmology model

    E-Print Network [OSTI]

    S. Capozziello; P. Martin-Moruno; C. Rubano

    2008-04-28T23:59:59.000Z

    We show that dust matter-dark energy combined phases can be achieved by the exact solution derived from a power law $f(R)$ cosmological model. This example answers the query by which a dust-dominated decelerated phase, before dark-energy accelerated phase, is needed in order to form large scale structures.

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

    SciTech Connect (OSTI)

    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

    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}< 15 K) since formation. The 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.

  4. From flux to dust mass: Does the grain-temperature distribution matter for estimates of cold dust masses in supernova remnants?

    E-Print Network [OSTI]

    Mattsson, Lars; Andersen, Anja C; Matsuura, Mikako

    2015-01-01T23:59:59.000Z

    The amount of dust estimated from infrared to sub-millimetre (submm) observations strongly depends on assumptions of different grain sizes, compositions and optical properties. Here we use a simple model of thermal emission from cold silicate/carbon dust at a range of dust grain temperatures and fit the spectral energy distribution (SED) of the Crab Nebula as a test. This can lower the derived dust mass for the Crab by ~50% and 30-40% for astronomical silicates and amorphous carbon grains compared to recently published values (0.25M_sun -> 0.12M_sun and 0.12M_sun -> 0.072M_sun, respectively), but the implied dust mass can also increase by as much as almost a factor of six (0.25M_sun -> 1.14M_sun and 0.12M_sun -> 0.71M_sun) depending on assumptions regarding the sizes/temperatures of the coldest grains. The latter values are clearly unrealistic due to the expected metal budget, though. Furthermore, we show by a simple numerical experiment that if a cold-dust component does have a grain-temperature distribution...

  5. Condensed matter astrophysics: A prescription for determining the species-specific composition and quantity of interstellar dust using x-rays

    SciTech Connect (OSTI)

    Lee, Julia C.; Xiang, Jingen; Ravel, Bruce; Kortright, Jeffrey B; Flanagan, Kathryn

    2009-01-05T23:59:59.000Z

    We present a newtechnique for determining the quantity and composition of dust in astrophysical environments using<6 keV X-rays.We argue that high-resolution X-ray spectra as enabled by the Chandra and XMM-Newton gratings should be considered a powerful and viable new resource for delving into a relatively unexplored regime for directlydetermining dust properties: composition, quantity, and distribution.We present initial cross section measurements of astrophysically likely iron-based dust candidates taken at the Lawrence Berkeley National Laboratory Advanced Light Source synchrotron beamline, as an illustrative tool for the formulation of our technique for determining the quantity and composition of interstellar dust with X-rays. (Cross sections for the materials presented here will be made available for astrophysical modeling in the near future.) Focused at the 700 eV Fe LIII and LII photoelectric edges, we discuss a technique for modeling dust properties in the soft X-rays using L-edge data to complement K-edge X-ray absorption fine structure analysis techniques discussed by Lee& Ravel. The paper is intended to be a techniques paper of interest and useful to both condensed matter experimentalists andastrophysicists. For the experimentalists, we offer a new prescription for normalizing relatively low signal-to-noise ratio L-edge cross section measurements. For astrophysics interests, we discuss the use of X-ray absorption spectra for determining dust composition in cold and ionized astrophysical environments and a new method for determining species-specific gas and dust ratios. Possible astrophysical applications of interest, including relevance to Sagittarius A*, are offered. Prospects for improving on this work in future X-ray missions with higher throughput and spectral resolution are also presented in the context of spectral resolution goals for gratings and calorimeters, for proposed and planned missions such as Astro-H and the International X-ray Observatory.

  6. Constraining the Amount of Circumstellar Matter and Dust around Type Ia Supernovae through Near-Infrared Echo

    E-Print Network [OSTI]

    Maeda, Keiichi; Motohara, Kentaro

    2014-01-01T23:59:59.000Z

    Circumstellar (CS) environment is a key in understanding progenitors of type Ia supernovae (SNe Ia) as well as an origin of peculiar extinction property toward SNe Ia for cosmological application. It has been suggested that multiple em scatterings of SN photons on CS dust might explain a non-standard reddening law. In this paper, we investigate an effect of re-emissions of SN photons by CS dust in the Infrared (IR) wavelengths. We show that this effect allows observed IR light curves to be used to place a constraint on position/size and the amount of CSM dust. We apply the method to observed NIR SN Ia samples, showing that meaningful upper limits, even under conservative assumptions, on the CS dust mass can be derived. We thereby clarify a difficulty of the CS dust scattering model to be a general explanation for the peculiar reddening law, while it may still apply to a sub-sample of highly-reddened SNe Ia. For SNe Ia in general, environment at the interstellar scale should be responsible for the non-standard...

  7. Potential adverse health effects of wood smoke

    SciTech Connect (OSTI)

    Pierson, W.E.; Koenig, J.Q.; Bardana, E.J. Jr.

    1989-09-01T23:59:59.000Z

    The use of wood stoves has increased greatly in the past decade, causing concern in many communities about the health effects of wood smoke. Wood smoke is known to contain such compounds as carbon monoxide, nitrogen oxides, sulfur oxides, aldehydes, polycyclic aromatic hydrocarbons, and fine respirable particulate matter. All of these have been shown to cause deleterious physiologic responses in laboratory studies in humans. Some compounds found in wood smoke--benzo(a)pyrene and formaldehyde--are possible human carcinogens. Fine particulate matter has been associated with decreased pulmonary function in children and with increased chronic lung disease in Nepal, where exposure to very high amounts of wood smoke occurs in residences. Wood smoke fumes, taken from both outdoor and indoor samples, have shown mutagenic activity in short-term bioassay tests. Because of the potential health effects of wood smoke, exposure to this source of air pollution should be minimal.29 references.

  8. Dust collector

    SciTech Connect (OSTI)

    Lynch, G.; Mc Lukie, P.; Mark, D.; Vincent, J.H.

    1987-06-23T23:59:59.000Z

    This patent describes a personal dust sampler comprising: a sampler body having an entry aperture exposed to ambient air and an air exit sealably attachable to pump means; a removable filter cassette mounted with the body; means for removably holding cassette in position; the filter cassette having an internal filter and comprises an entry for air which may be contaminated with dust; the entry having a cylindrical upstanding wall open to the air at one end and communicating with a first side of the internal filter at the other end; a cassette air exit communicating with the other side of the internal filter and sealably connecting with the air exit of the sampler body; the cylindrical upstanding wall of the cassette air entry protruding through the entry aperture to form a lip cooperating with the sampler body to provide an aspiration efficiency with respect to dust of approximately unity.

  9. Curing and Smoking Poultry

    E-Print Network [OSTI]

    Denton, James H.

    1999-11-10T23:59:59.000Z

    Cured and smoked poultry is a taste-tempting treat. In addition to having a distinctive aroma and flavor, it also has eye appeal unmatched by any other meat product. Once cured and smoked, the meat is easily and quickly prepared for serving and can... be stored in the home refrigerator for as long as 2 weeks. Meats that are only smoked and not cured can be stored no longer than other cooked meats. The curing and smoking process produces meat that is distinctly different from meat that has only been smoked...

  10. The AIR, the WATER, the SUN, the DUST,

    E-Print Network [OSTI]

    Bandettini, Peter A.

    by pollutants and other chemicals in the air and in the home. Doctors can test to find out which substances (durmuhTIE-tiss) Emphysema (EM-fuh-ZEE-ma)Air pollution and cigarette smoke can break down sensitive#12;The AIR, the WATER, the SUN, the DUST, PLANTS and ANIMALS, and the CHEMICALS and METALS of our

  11. Dust Measurements in Tokamaks

    SciTech Connect (OSTI)

    Rudakov, D; Yu, J; Boedo, J; Hollmann, E; Krasheninnikov, S; Moyer, R; Muller, S; Yu, A; Rosenberg, M; Smirnov, R; West, W; Boivin, R; Bray, B; Brooks, N; Hyatt, A; Wong, C; Fenstermacher, M; Groth, M; Lasnier, C; McLean, A; Stangeby, P; Ratynskaia, S; Roquemore, A; Skinner, C; Solomon, W M

    2008-04-23T23:59:59.000Z

    Dust production and accumulation impose safety and operational concerns for ITER. Diagnostics to monitor dust levels in the plasma as well as in-vessel dust inventory are currently being tested in a few tokamaks. Dust accumulation in ITER is likely to occur in hidden areas, e.g. between tiles and under divertor baffles. A novel electrostatic dust detector for monitoring dust in these regions has been developed and tested at PPPL. In DIII-D tokamak dust diagnostics include Mie scattering from Nd:YAG lasers, visible imaging, and spectroscopy. Laser scattering resolves size of particles between 0.16-1.6 {micro}m in diameter; the total dust content in the edge plasmas and trends in the dust production rates within this size range have been established. Individual dust particles are observed by visible imaging using fast-framing cameras, detecting dust particles of a few microns in diameter and larger. Dust velocities and trajectories can be determined in 2D with a single camera or 3D using multiple cameras, but determination of particle size is problematic. In order to calibrate diagnostics and benchmark dust dynamics modeling, pre-characterized carbon dust has been injected into the lower divertor of DIII-D. Injected dust is seen by cameras, and spectroscopic diagnostics observe an increase of carbon atomic, C2 dimer, and thermal continuum emissions from the injected dust. The latter observation can be used in the design of novel dust survey diagnostics.

  12. Dust-regulated galaxy formation and evolution:A new chemodynamical model with live dust particles

    E-Print Network [OSTI]

    Bekki, Kenji

    2015-01-01T23:59:59.000Z

    Interstellar dust plays decisive roles in the conversion of neutral to molecular hydrogen (H_2), the thermodynamical evolution of interstellar medium (ISM), and the modification of spectral energy distributions (SEDs) of galaxies. These important roles of dust have not been self-consistently included in previous numerical simulations of galaxy formation and evolution. We have therefore developed a new model by which one can investigate whether and how galaxy formation and evolution can be influenced by dust-related physical processes such as photo-electric heating, H_2 formation on dust, and stellar radiation pressure on dust in detail. A novel point of the model is that different dust species in a galaxy are represented by `live dust' particles (i.e., not test particles). Therefore, dust particles in a galaxy not only interact gravitationally with all four components of the galaxy (i.e., dark matter, stars, gas, and dust) but also are grown and destroyed through physical processes of ISM. First we describe a...

  13. Niamey Dust Observations

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Flynn, Connor

    Niamey aerosol are composed of two main components: dust due to the proximity of the Sahara Desert, and soot from local and regional biomass burning. The purpose of this data product is to identify when the local conditions are dominated by the dust component so that the properties of the dust events can be further studied.

  14. Haul road dust control

    SciTech Connect (OSTI)

    Reed, W.R.; Organiscak, J.A. [NIOSH-PRL, Pittsburgh, PA (United States)

    2007-10-15T23:59:59.000Z

    A field study was conducted to measure dust from haul trucks at a limestone quarry and a coal preparation plant waste hauling operation. The study found that primarily wind, distance and road treatment conditions notably affected the dust concentrations at locations next to, 50 ft from, and 100 ft away from the unpaved haulage road. Airborne dust measured along the unpaved haul road showed that high concentrations of fugitive dust can be generated with these concentrations rapidly decreasing to nearly background levels within 100 ft of the road. Instantaneous respirable dust measurements illustrated that the trucks generate a real-time dust cloud that has a peak concentration with a time-related decay rate as the dust moves past the sampling locations. The respirable dust concentrations and peak levels were notably diminished as the dust cloud was transported, diluted, and diffused by the wind over the 100 ft distance from the road. Individual truck concentrations and peak levels measured next to the dry road surface test section were quite variable and dependent on wind conditions, particularly wind direction, with respect to reaching the sampling location. The vast majority of the fugitive airborne dust generated from unpaved and untreated haulage roads was non-respirable. 6 figs.

  15. Three-dimensional numerical modeling of smoke injection from large fires in the early post-nuclear-exchange environment

    SciTech Connect (OSTI)

    Bradley, M.M.; Peterson, K.R.; Rodriguez, D.J.

    1988-11-17T23:59:59.000Z

    During the hours immediately following a nuclear exchange, large fires could inject enormous quantities of smoke into the atmosphere. This smoke, together with dust from surface bursts, would severely restrict visibilities and darken the skies over large areas for days. This, in turn, could impact surface and air operations and systems. These effects could be mitigated by various scavenging mechanisms within the convective clouds that form above the fires. In order to evaluate impacts of post-nuclear-exchange smoke injection, we are developing a three-dimensional numerical smoke plume model (OCTET) to simulate the dynamics and microphysical processes within smoke plumes and convective clouds above large fires. This model is based on the dynamic framework of the Klemp-Wilhelmson (1978) convective storm model and includes parameterizations of scavenging processes. In addition, we are combining results of laboratory research, field experiments, and detailed numerical modeling of cloud microphysical processes in order to better understand smoke scavenging mechanisms. In this brief demonstration of capabilities, we present results from the OCTET model and from a three-dimensional mesoscale model. The smoke plume and fire-induced cloud simulations demonstrate the effects of nucleation scavenging, seasonal variation of atmospheric stability, and various fuel sources. The mesoscale simulations (that use the plume model output as input) demonstrate the mesoscale transport and diffusion of smoke and predict optical depths over the hypothetical target area. No dust effects have been included in these simulations. 2 refs., 8 figs.

  16. Dust around Type Ia supernovae

    E-Print Network [OSTI]

    Wang, Lifan

    2005-01-01T23:59:59.000Z

    Dust around Type Ia supernovae Lifan Wang 1,2 LawrenceIa. Subject headings: Supernovae: General, Dust, Extinctionline) bands for Type Ia supernovae. (a), upper panel, shows

  17. Secondary dust density waves excited by nonlinear dust acoustic waves

    SciTech Connect (OSTI)

    Heinrich, J. R.; Kim, S.-H.; Meyer, J. K.; Merlino, R. L. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States); Rosenberg, M. [Department of Electrical and Computer Engineering, University of California, San Diego, California 92093 (United States)

    2012-08-15T23:59:59.000Z

    Secondary dust density waves were observed in conjunction with high amplitude (n{sub d}/n{sub d0}>2) dust acoustic waves (DAW) that were spontaneously excited in a dc glow discharge dusty plasma in the moderately coupled, {Gamma}{approx}1, state. The high amplitude dust acoustic waves produced large dust particle oscillations, displacements, and trapping. Secondary dust density waves were excited in the wave troughs of the high amplitude DAWs. The waveforms, amplitudes, wavelengths, and wave speeds of the primary DAWs and the secondary waves were measured. A dust-dust streaming instability is discussed as a possible mechanism for the production of the secondary waves.

  18. Dust resuspension as a contaminant source and transport pathway

    SciTech Connect (OSTI)

    Loosmore, G.A,; Hunt, J.R.

    1999-07-01T23:59:59.000Z

    Numerous environmental contaminants sorb to dust particles or exist as particles, including metals, hydrophobic organic compounds, asbestos, pollens, and microbial pathogens. Wind resuspension of dust and other particulate matter provides a dust source for the atmosphere and a contaminant transport pathway. Not only do these materials pose a risk to human health, but also, resuspended dust particles are believed to play a role in global climate change and chemical reactions in the atmosphere. The conditions under which contaminated sites are vulnerable to wind resuspension are not generally known, as the basic physics of the problem are poorly understood. Field data show tremendous variability. Conventional dust flux models assume that dust resuspension occurs only for high winds and then only temporarily, with a transient dust flux occurring only when the bed is first exposed to the high wind. The surface is then assumed to stabilize such that no further dust moves until the surface is disturbed or a higher wind occurs. Recent wind tunnel experiments demonstrate that surfaces yield continuous steady dust fluxes under steady wind conditions well beyond the initial high transient flux, even when no erosion is visible and the velocity is below the predicted threshold velocity for movement. This average steady-state dust flux increases with average wind speed. Ongoing work is investigating the influence of air relative humidity on these processes. Contaminant resuspension models capture trends only and fail to predict sporadic high flux events that may control doses. Successful modeling of contaminant resuspension will depend on development of better dust flux predictions. Risk analyses require better predictive modeling, necessitating a deeper understanding of the underlying phenomena.

  19. Electrostatic dust detector

    DOE Patents [OSTI]

    Skinner, Charles H. (Lawrenceville, NJ)

    2006-05-02T23:59:59.000Z

    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.

  20. Dust cluster explosion

    SciTech Connect (OSTI)

    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

    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).

  1. 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

  2. Collapsing Inhomogeneous Dust Fluid in the Background of Dark Energy

    E-Print Network [OSTI]

    Tanwi Bandyopadhyay; Subenoy Chakraborty

    2006-05-11T23:59:59.000Z

    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

  3. Smoke and Visible Emissions (New Mexico)

    Broader source: Energy.gov [DOE]

    This rule establishes controls on smoke and visible emissions from certain sources.  This rule is not intended to preempt any more stringent controls on smoke and visible emissions provided in any...

  4. Centre for Smoking Cessation and Training

    E-Print Network [OSTI]

    Saunders, Mark

    Centre for Smoking Cessation and Training The NHS Centre for Smoking Cessation and Training (NCSCT and commissioners commission and provide training and continuing support to allow staff to achieve the required of training courses advise the Department of Health on issues relating to the Stop Smoking Services

  5. 6, 96559722, 2006 Arctic smoke

    E-Print Network [OSTI]

    Boyer, Edmond

    Discussions Arctic smoke ­ record high air pollution levels in the European Arctic due to agricultural fires into the European Arctic and caused the most severe air pollution episodes ever recorded there. This paper confirms that biomass burning (BB) was in-5 deed the source of the observed air pollution, studies the transport

  6. Cotton Gin Dust Explosibility Determinations 

    E-Print Network [OSTI]

    Vanderlick, Francis Jerome

    2014-01-06T23:59:59.000Z

    COTTON GIN DUST EXPLOSIBILITY DETERMINATIONS A Thesis by FRANCIS JEROME VANDERLICK Submitted to the Office of Graduate and Professional Studies of Texas A&M University in partial fulfillment of the requirements for the degree... Francis Jerome Vanderlick ii ABSTRACT Following the recent Imperial sugar dust explosion in 2008, a comprehensive survey of past dust explosions was conducted by the Occupational Safety and Health Administration (OSHA) to determine potential...

  7. Cotton Gin Dust Explosibility Determinations

    E-Print Network [OSTI]

    Vanderlick, Francis Jerome

    2014-01-06T23:59:59.000Z

    test method was found to be flawed. It used pressure as the only criterion for a dust explosion, utilized high energy ignition sources, limited the amount of oxygen, and had no requirement for a dust to have a minimum explosible concentration (MEC...

  8. Cyborg Bugs... and Neural Dust

    E-Print Network [OSTI]

    California at Irvine, University of

    Cyborg Bugs... and Neural Dust Michel M. Maharbiz © 2014 D.J. Seo Elad Alon system Seo D, et al. "Neural Dust: An Ultrasonic, Low Power SoluNon for Chronic Brain-Machine Interfaces," arXiv, Jul. 2013 Seo D, et al. "In Vitro Characteriza

  9. Iron Speciation in Urban Dust

    SciTech Connect (OSTI)

    E Elzinga; Y Gao; J Fitts; R Tappero

    2011-12-31T23:59:59.000Z

    An improved understanding of anthropogenic impacts on ocean fertility requires knowledge of anthropogenic dust mineralogy and associated Fe speciation as a critical step toward developing Fe solubility models constrained by mineralogical composition. This study explored the utility of micro-focused X-ray absorption spectroscopy ({mu}-XAS) in characterizing the speciation of Fe in urban dust samples. A micro-focused beam of 10 x 7 {micro}m made possible the measurement of the Fe K edge XAS spectra of individual dust particles in the PM5.6 size fraction collected in Newark, New Jersey, USA. Spectral analysis indicated the presence of mixtures of Fe-containing minerals within individual dust particles; we observed significant magnetite content along with other Fe(III)-(hydr)oxide minerals which could not be conclusively identified. Our data indicate that detailed quantitative determination of Fe speciation requires extended energy scans to constrain the types and relative abundance of Fe species present. We observe heterogeneity in Fe speciation at the dust particle level, which underscores the importance of analyzing a statistically adequate number of particles within each dust sample. Where possible, {mu}-XAS measurements should be complemented with additional characterization techniques such as {mu}-XRD and bulk XAS to obtain a comprehensive picture of the Fe speciation in dust materials. X-ray microprobes should be used to complement bulk methods used to determine particle composition, methods that fail to record particle heterogeneity.

  10. Tobacco use in shisha: studies on waterpipe smoking in Egypt

    E-Print Network [OSTI]

    World Health Organization

    2006-01-01T23:59:59.000Z

    on waterpipe smoking in Egypt / WHO Regional Of?ce for theHealth surveys 5. Smoking – Egypt I. Title II Regional Of?ceshisha) smoking in cafés in Egypt. Journal of the Egyptian

  11. NASA Contractor Re Lunar Dust T

    E-Print Network [OSTI]

    Rathbun, Julie A.

    Photovoltaic Array Performance ..................................................................... 24 Correlation of Dust Accumulation and Power Component Performance ....................................... 22 Radiator Performance ............................................................................. 22

  12. adolescent smoking behavior: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Potential Smoke Environmental Sciences and Ecology Websites Summary: Smoke Production and Fire Hazard1 Roger D. Ottmar2 and Ernesto Alvarado3 During the past 80 years potential...

  13. adult smoking ethnic: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Potential Smoke Environmental Sciences and Ecology Websites Summary: Smoke Production and Fire Hazard1 Roger D. Ottmar2 and Ernesto Alvarado3 During the past 80 years potential...

  14. Iron speciation in urban dust

    SciTech Connect (OSTI)

    Elzinga, E.J.; Fitts, J.; Gao, Y.; Tappero, R.

    2011-08-01T23:59:59.000Z

    An improved understanding of anthropogenic impacts on ocean fertility requires knowledge of anthropogenic dust mineralogy and associated Fe speciation as a critical step toward developing Fe solubility models constrained by mineralogical composition. This study explored the utility of micro-focused X-ray absorption spectroscopy ({mu}-XAS) in characterizing the speciation of Fe in urban dust samples. A micro-focused beam of 10 x 7 {mu}m made possible the measurement of the Fe K edge XAS spectra of individual dust particles in the PM5.6 size fraction collected in Newark, New Jersey, USA. Spectral analysis indicated the presence of mixtures of Fe-containing minerals within individual dust particles; we observed significant magnetite content along with other Fe(III)-(hydr)oxide minerals which could not be conclusively identified. Our data indicate that detailed quantitative determination of Fe speciation requires extended energy scans to constrain the types and relative abundance of Fe species present. We observe heterogeneity in Fe speciation at the dust particle level, which underscores the importance of analyzing a statistically adequate number of particles within each dust sample. Where possible, {mu}-XAS measurements should be complemented with additional characterization techniques such as {mu}-XRD and bulk XAS to obtain a comprehensive picture of the Fe speciation in dust materials. X-ray microprobes should be used to complement bulk methods used to determine particle composition, methods that fail to record particle heterogeneity. Keywords - Urban dust; Iron; Speciation; Micro-focused X-ray absorption spectroscopy.

  15. Measurements of Smoke Characteristics in HVAC Ducts 

    E-Print Network [OSTI]

    Wolin, Steven D; Ryder, Noah L; Leprince, Frederic; Milke, James; Mowrer, Frederick; Torero, Jose L

    2001-01-01T23:59:59.000Z

    The characteristics of smoke traveling in an HVAC duct have been observed along with the response of selected duct smoke detectors. The simulated HVAC system consists of a 9 m long duct, 0.45 m in diameter. An exhaust fan is placed at one end...

  16. 5, 59095934, 2005 Effect of smoke on

    E-Print Network [OSTI]

    Boyer, Edmond

    Discussions Effect of smoke on the transmissivity of photosynthetically active radiation inside the canopy M) and RaCCI (Radiation, Cloud, and Climate Interactions in the Amazon during the Dry-to-Wet TransitionACPD 5, 5909­5934, 2005 Effect of smoke on transmission of PAR M. Yamasoe et al. Title Page

  17. The dust and gas content of the Crab Nebula

    E-Print Network [OSTI]

    Owen, P J

    2015-01-01T23:59:59.000Z

    We have constructed MOCASSIN photoionization plus dust radiative transfer models for the Crab Nebula core-collapse supernova (CCSN) remnant, using either smooth or clumped mass distributions, in order to determine the chemical composition and masses of the nebular gas and dust. We computed models for several different geometries suggested for the nebular matter distribution but found that the observed gas and dust spectra are relatively insensitive to these geometries, being determined mainly by the spectrum of the pulsar wind nebula which ionizes and heats the nebula. Smooth distribution models are ruled out since they require 16-49 Msun of gas to fit the integrated optical nebular line fluxes, whereas our clumped models require 7.0 Msun of gas. neither of which can be matched by current CCSN yield predictions. A global gas-phase C/O ratio of 1.65 by number is derived, along with a He/H number ratio of 1.85, A carbonaceous dust composition is favoured by the observed gas-phase C/O ratio: amorphous carbon clu...

  18. aluminum dust explosion: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    dust are investigated in order to study their potential Aste, Andreas 369 EFFECT OF COAL DUST ONEFFECT OF COAL DUST ON RAILROAD BALLAST STRENGTHRAILROAD BALLAST STRENGTH...

  19. acute coal dust: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    galaxies, a method for the dust mass evaluation, which accounts for the dust temperature distribution, is here presented and discussed. The derived dust masses turn out to...

  20. autogenous bone dust: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    galaxies, a method for the dust mass evaluation, which accounts for the dust temperature distribution, is here presented and discussed. The derived dust masses turn out to...

  1. airborne respirable dust: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Summary: Interstellar Medium: dust Interstellar dust Dust grains (silicatecarbon cores, ice mantles , 1-2 Thermal emission: mm, submm, FIR (optically thin) 12;Interstellar...

  2. Energy conditions, traversable wormholes and dust shells

    E-Print Network [OSTI]

    Francisco S. N. Lobo

    2004-10-18T23:59:59.000Z

    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.

  3. Non-marginally bound inhomogeneous dust collapse in higher dimensional space-time

    E-Print Network [OSTI]

    S. G. Ghosh; A. Banerjee

    2002-12-16T23:59:59.000Z

    We investigate the occurrence and nature of a naked singularity in the gravitational collapse of an inhomogeneous dust cloud described by a self-similar higher dimensional Tolman-Bondi space-time. Bound, marginally bound and unbound space-times are analyzed. The degree of inhomogeneity of the collapsing matter necessary to form a naked singularity is given.

  4. Glass Frit Clumping And Dusting

    SciTech Connect (OSTI)

    Steimke, J. L.

    2013-09-26T23:59:59.000Z

    DWPF mixes a slurry of glass frit (Frit 418) and dilute (1.5 wt%) formic acid solution with high level waste in the Slurry Mix Evaporator (SME). There would be advantages to introducing the frit in a non-slurry form to minimize water addition to the SME, however, adding completely dry frit has the potential to generate dust which could clog filters or condensers. Prior testing with another type of frit, Frit 320, and using a minimal amount of water reduced dust generation, however, the formation of hard clumps was observed. To examine options and behavior, a TTQAP [McCabe and Stone, 2013] was written to initiate tests that would address these concerns. Tests were conducted with four types of glass frit; Frit 320, DWPF Frit 418, Bekeson Frit 418 and Multi-Aspirator Frit 418. The last two frits are chemically identical to DWPF Frit 418 but smaller particles were removed by the respective vendors. Test results on Frit Clumping and Dusting are provided in this report. This report addresses the following seven questions. Short answers are provided below with more detailed answers to follow. 1. Will the addition of a small amount of water, 1.5 wt%, to dry DWPF Frit 418 greatly reduce the dust generation during handling at DWPF? a. Yes, a small scale test showed that adding a little water to the frit greatly reduced dust generation during handling. 2. Will the addition of small amounts of water to the frit cause clumping that will impair frit handling at DWPF? a. No, not with Frit 418. Although clumps were observed to form when 1.5 wt% water was mixed with DWPF Frit 418, then compressed and air-dried overnight, the clumps were easily crushed and did not form the hardened material noted when Frit 320 was tested. 3. What is the measured size distribution of dust generated when dry frit is handled? (This affects the feasibility and choice of processing equipment for removing the dust generating fraction of the frit before it is added to the SME.) a. The size distribution for the dust removed from fresh DWPF Frit 418 while it was being shaken in a small scale LabRAM test was measured. The median size on a volume basis was 7.6 ?m and 90% of the frit particles were between 1.6 and 28 ?m. The mass of dust collected using this test protocol was much less than 1% of the original frit. 4. Can the dust be removed in a small number of processing steps and without the larger frit particles continuing to spall additional dust sized particles? a. Test results using a LabRAM were inconclusive. The LaRAM performs less efficient particle size separation than the equipment used by Bekeson and Multi-Aspirator. 5. What particle size of frit is expected to create a dust problem? a. The original criterion for creating a dusting problem was those particle sizes that were readily suspended when being shaken. For that criterion calculations and Microtrac size analyses indicated that particles smaller than 37 ?m are likely dust generators. Subsequently a more sophisticated criterion for dust problem was considered, particle sizes that would become suspended in the air flow patterns inside the SME and possibly plug the condenser. That size may be larger than 37 ?m but has not yet been determined. 6. If particles smaller than 37 ?m are removed will bulk dust generation be eliminated? a. Video-taped tests were performed using three gallons each of three types of frit 418, DWPF frit, Bekeson frit and Multi-Aspirator frit. Frit was poured through air from a height of approximately eight feet into a container half filled with water. Pouring Bekeson frit or Multi-Aspirator frit generated markedly less visible dust, but there was still a significant amount, which still has the potential of causing a dust problem. 7. Can completely dry frit be poured into the SME without having dust plug the condenser at the top of the vessel? a. Because of the complexity of air currents inside the SME and the difficulty of defensible size scaling a more prototypical test will be required to answer this question. We recommend construction of a full scale

  5. Nonlinear dust acoustic waves and shocks

    SciTech Connect (OSTI)

    Merlino, R. L.; Heinrich, J. R.; Hyun, S.-H.; Meyer, J. K. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States)

    2012-05-15T23:59:59.000Z

    We describe experiments on (1) nonlinear dust acoustic waves and (2) dust acoustic shocks performed in a direct current (DC) glow discharge dusty plasma. First, we describe experiments showing nonlinear dust acoustic waves characterized by waveforms of the dust density that are typically sharper in the wave crests and flatter in the wave troughs (compared to sinusoidal waves), indicating the development of wave harmonics. We discuss this behavior in terms of a second-order fluid theory for dust acoustic waves. Second, experimental observations of the propagation and steepening of large-amplitude dust acoustic waves into dust acoustic shock waves are presented. The observed shock wave evolution is compared with numerical calculations based on the Riemann solution of the fully nonlinear fluid equations for dust acoustic waves.

  6. EFFECT OF COAL DUST ONEFFECT OF COAL DUST ON RAILROAD BALLAST STRENGTHRAILROAD BALLAST STRENGTH

    E-Print Network [OSTI]

    Barkan, Christopher P.L.

    1 EFFECT OF COAL DUST ONEFFECT OF COAL DUST ON RAILROAD BALLAST STRENGTHRAILROAD BALLAST STRENGTH for Laboratory StudyFouling Mechanism / Need for Laboratory Study Mechanical Properties of Coal DustMechanical Properties of Coal Dust Grain Size AnalysisGrain Size Analysis AtterbergAtterberg LimitsLimits Specific

  7. Adding coal dust to coal batch

    SciTech Connect (OSTI)

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

    2009-05-15T23:59:59.000Z

    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.

  8. Characterization of jovian plasma embedded dust particles

    E-Print Network [OSTI]

    Amara L. Graps

    2006-09-12T23:59:59.000Z

    As the data from space missions and laboratories improve, a research domain combining plasmas and charged dust is gaining in prominence. Our solar system provides many natural laboratories such as planetary rings, comet comae and tails, ejecta clouds around moons and asteroids, and Earth's noctilucent clouds for which to closely study plasma-embedded cosmic dust. One natural laboratory to study electromagnetically-controlled cosmic dust has been provided by the Jovian dust streams and the data from the instruments which were on board the Galileo spacecraft. Given the prodigious quantity of dust poured into the Jovian magnetosphere by Io and its volcanoes resulting in the dust streams, the possibility of dusty plasma conditions exist. This paper characterizes the main parameters for those interested in studying dust embedded in a plasma with a focus on the Jupiter environment. I show how to distinguish between dust-in-plasma and dusty-plasma and how the Havnes parameter P can be used to support or negate the possibility of collective behavior of the dusty plasma. The result of applying these tools to the Jovian dust streams reveals mostly dust-in-plasma behavior. In the orbits displaying the highest dust stream fluxes, portions of orbits E4, G7, G8, C21 satisfy the minimum requirements for a dusty plasma. However, the P parameter demonstrates that these mild dusty plasma conditions do not lead to collective behavior of the dust stream particles.

  9. Role of positively charged dust grains on dust acoustic wave propagation in presence of nonthermal ions

    SciTech Connect (OSTI)

    Sarkar, Susmita; Maity, Saumyen [Department of Applied Mathematics, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata 700009 (India)] [Department of Applied Mathematics, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata 700009 (India)

    2013-08-15T23:59:59.000Z

    An expression for ion current flowing to the dust grains is proposed, when dust charge is positive and the ions are nonthermal. Secondary electron emission has been considered as the source of positive charging of the dust grains. Investigation shows that presence of positively charged dust grains along with thermal electrons and nonthermal ions generate purely growing dust acoustic waves for both the cases of ion nonthermal parameter greater than one and less than one. In the later case, the growth is conditional.

  10. Expanded solid matter: Two-dimensional LJ modeling F.H. Stillinger *, D.K. Stillinger

    E-Print Network [OSTI]

    Stillinger, Frank

    and technological importance of expanded solid forms of matter such as aerogels indicate the need for related. Keywords: Aerogels; Lennard-Jones model; Inherent structures; Fractal clusters; Burgers vector solid matter is provided by the family of silica-based aerogels (``solid smoke'') that can have mass

  11. Dark Matters

    ScienceCinema (OSTI)

    Joseph Silk

    2010-01-08T23:59:59.000Z

    One of the greatest mysteries in the cosmos is that it is mostly dark.  Astronomers and particle physicists today are seeking to unravel the nature of this mysterious, but pervasive dark matter which has profoundly influenced the formation of structure in the universe.  I will describe the complex interplay between galaxy formation and dark matter detectability and review recent attempts to measure particle dark matter by direct and indirect means.

  12. The effect of smoke, dust, and pollution aerosol on shallow cloud development over the Atlantic Ocean

    E-Print Network [OSTI]

    Daniel, Rosenfeld

    radiation by aerosols, however, can reduce the cloud cover. The net aerosol effect on clouds is currently- induced cloud changes, and 1 3 is due to aerosol direct radiative effect. cloud cover cloud height understand the processes. The radiative effect at the top of the atmosphere incurred by the aerosol effect

  13. ORIGIN OF DUST AROUND V1309 SCO

    SciTech Connect (OSTI)

    Zhu, Chunhua; Lü, Guoliang; Wang, Zhaojun, E-mail: guolianglv@gmail.com [School of Physical Science and Technology, Xinjiang University, Urumqi, 830046 (China)

    2013-11-01T23:59:59.000Z

    The origin of dust grains in the interstellar medium is still an unanswered problem. Nicholls et al. found the presence of a significant amount of dust around V1309 Sco, which may originate from the merger of a contact binary. We investigate the origin of dust around V1309 Sco and suggest that these dust grains are produced in the binary-merger ejecta. By means of the AGBDUST code, we estimate that ?5.2 × 10{sup –4} M{sub ?} dust grains are produced with a radii of ?10{sup –5} cm. These dust grains are mainly composed of silicate and iron grains. Because the mass of the binary merger ejecta is very small, the contribution of dust produced by binary merger ejecta to the overall dust production in the interstellar medium is negligible. However, it is important to note that the discovery of a significant amount of dust around V1309 Sco offers a direct support for the idea that common-envelope ejecta provides an ideal environment for dust formation and growth. Therefore, we confirm that common envelope ejecta can be important source of cosmic dust.

  14. Astrophysics of Dust in Cold Clouds

    E-Print Network [OSTI]

    B. T. Draine

    2003-04-28T23:59:59.000Z

    Nine lectures reviewing the astrophysics of dust in interstellar clouds. Topics include: (1) Summary of observational evidence concerning interstellar dust: broadband extinction, scattering of starlight, polarization of starlight, spectroscopy of dust, IR and FIR emission, and depletions of grain-forming elements. (2) Optics of interstellar dust grains: dielectric functions of nonconducting and conducting materials, calculational techniques, formulae valid in the Rayleigh limit, Kramers-Kronig relations, microwave emission mechanisms, and X-ray scattering. (3) IR and FIR emission: heating of interstellar dust, including single-photon heating, and resulting IR emission spectrum. (4) Charging of dust grains: collisional charging, photoelectric emission, and resulting charge distribution functions. (5) Dynamics: gas drag, Lorentz force, forces due to anisotropic radiation, and resulting drift velocities. (6) Rotational dynamics: brownian rotation, suprathermal rotation, and effects of starlight torques. (7) Alignment of interstellar dust: observations and theories. (8) Evolution of the grain population: dust formation in outflows, grain growth in the ISM, photodesorption, and grain destruction in shock waves. (9) Effects of dust grains: photoelectric heating, H2 formation, ion recombination, coupling of gas to magnetic fields, and dust grains as indicators of magnetic field direction.

  15. Dusty supernovae running the thermodynamics of the matter reinserted within young and massive super stellar clusters

    SciTech Connect (OSTI)

    Tenorio-Tagle, Guillermo; Silich, Sergiy; Martínez-González, Sergio [Instituto Nacional de Astrofísica Óptica y Electrónica, AP 51, 72000 Puebla (Mexico); Muñoz-Tuñón, Casiana [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Palouš, Jan; Wünsch, Richard, E-mail: gtt@inaoep.mx, E-mail: cmt@ll.iac.es [Astronomical Institute, Academy of Sciences of the Czech Republic, Bo?ní II 1401, 141 31 Prague (Czech Republic)

    2013-12-01T23:59:59.000Z

    Following the observational and theoretical evidence that points at core-collapse supernovae (SNe) as major producers of dust, here we calculate the hydrodynamics of the matter reinserted within young and massive super stellar clusters under the assumption of gas and dust radiative cooling. The large SN rate expected in massive clusters allows for a continuous replenishment of dust immersed in the high temperature thermalized reinserted matter and warrants a stationary presence of dust within the cluster volume during the type II SN era. We first show that such a balance determines the range of the dust-to-gas-mass ratio, and thus the dust cooling law. We then search for the critical line that separates stationary cluster winds from the bimodal cases in the cluster mechanical luminosity (or cluster mass) versus cluster size parameter space. In the latter, strong radiative cooling reduces considerably the cluster wind mechanical energy output and affects particularly the cluster central regions, leading to frequent thermal instabilities that diminish the pressure and inhibit the exit of the reinserted matter. Instead, matter accumulates there and is expected to eventually lead to gravitational instabilities and to further stellar formation with the matter reinserted by former massive stars. The main outcome of the calculations is that the critical line is almost two orders of magnitude or more, depending on the assumed value of V {sub A?}, lower than when only gas radiative cooling is applied. And thus, many massive clusters are predicted to enter the bimodal regime.

  16. acute smoking behavior: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    by passive smoking and support steps to reduce exposure to other people's smoke--in the home and in other settings. We thank Jackie Fawcett and June Atkinson 69 Public-Place...

  17. Smoking in top-grossing US movies 2014

    E-Print Network [OSTI]

    Polansky, Jonathan R; Titus, Kori; Atayeva, Renata; Glantz, Stanton A PhD

    2015-01-01T23:59:59.000Z

    Smoking in top?grossing US movies Jonathan R. PolanskyApril 23, 2015 Smoking in top?grossing US movies: 2014 | 2about 20 percent of all top?grossing films. Tobacco presence

  18. varicose veins smoking obesity swine flu high blood pressure

    E-Print Network [OSTI]

    Diggle, Peter J.

    varicose veins smoking obesity swine flu high blood pressure parkinson's stress depression muscle stiffness heart attack asthma low blood pressure alzheimer's cancer diabetes kidney failure dementia smoking obesity swine flu high blood pressure parkinson's stress depression muscle stiffness heart attack

  19. A METHODOLOGICAL APPROACH TO THE SPONTANEOUS COMBSTION OF AGRICULTURAL DUSTS

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    to the characterization of combustible dusts with respect tp self-heating and give results for certain agricultural dusts can be started by an extemal ignition source or by self-heating. Combustion of dust can occur associated with agricultural dusts. 3. SELF-HEATING OF AGRICULTURAL DUSTS The physical mechanism of self

  20. Optical Properties of Saharan Dust and Asian Dust: Application to Radiative Transfer Simulations

    E-Print Network [OSTI]

    Fang, Guangyang

    2012-07-16T23:59:59.000Z

    Because the bulk optical properties of dust are largely dependent on their chemical composition, published reports from numerous dust field studies enabled us to compile observation data sets to derive the effective complex refractive indices...

  1. Characterization of secondary grain dust explosions

    E-Print Network [OSTI]

    Schulman, Cheryl Wendler

    1983-01-01T23:59:59.000Z

    explosion These include& an ignition source; oxygeni s confined space; and fuel, which 1n most instances is grain dust held. in suspension at concentration levels in excess of the minimum explosive concentration (MEC) (Palmer, 197$). The MEC is defined.... as the minimum concentration of dust in a cloud. necessary for sustained flame propagation. The MEC is also sometimes referred to as the lower explosive limit (LZL). The lower level of explosibility for most dusts ranges from 20 to 70 This thesis follows...

  2. Speciation of Sb in airborne particulate matter, vehicle brake linings, and brake pad wear residues

    E-Print Network [OSTI]

    Short, Daniel

    Speciation of Sb in airborne particulate matter, vehicle brake linings, and brake pad wear residues: XAS XANES EXAFS Antimony Particulate matter Brake linings a b s t r a c t Insights into the speciation of Sb in samples of brake linings, brake pad wear residues, road dust, and atmospheric particulate

  3. Nuclear winter: smoke generation, deposition, and removal. Final report

    SciTech Connect (OSTI)

    Not Available

    1984-12-01T23:59:59.000Z

    The Nuclear Winter scenario predicts a major worldwide cooling arising from the large quantities of soot deposited in the atmosphere from fires ignited by the explosions in a large nuclear exchange. This document reviews the source function for smoke associated with urban and forest fires, addressing the smoke composition and predicted smoke cloud rise height. The interaction of the smoke cloud with the atmosphere is complex and depends on weather conditions. Results from past forest fires demonstrate what can actually happen to smoke clouds.

  4. asian sand dust: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    that trigger dust storms, and the lifting of dust by dust devils and other small-scale vortices. We also discuss the physics of wind-blown sand and dune formation on Venus...

  5. Effect of a polynomial arbitrary dust size distribution on dust acoustic solitons

    SciTech Connect (OSTI)

    Ishak-Boushaki, M.; Djellout, D.; Annou, R. [Faculty of Physics, USTHB, P.B. 32 El Alia, Bab-ezzouar, Algiers (Algeria)

    2012-07-15T23:59:59.000Z

    The investigation of dust-acoustic solitons when dust grains are size-distributed and ions adiabatically heated is conducted. The influence of an arbitrary dust size-distribution described by a polynomial function on the properties of dust acoustic waves is investigated. An energy-like integral equation involving Sagdeev potential is derived. The solitary solutions are shown to undergo a transformation into cnoidal ones under some physical conditions. The dust size-distribution can significantly affect both lower and upper critical Mach numbers for both solitons and cnoidal solutions.

  6. Rigidly rotating cylinders of charged dust

    E-Print Network [OSTI]

    B. V. Ivanov

    2002-07-02T23:59:59.000Z

    The gravitational field of a rigidly rotating cylinder of charged dust is found analytically. The general and all regular solutions are divided into three classes. The acceleration and the vorticity of the dust are given, as well as the conditions for the appearance of closed timelike curves.

  7. asian dust source: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Natural dust sources globally account for 75 % of emissions; anthropogenic, 25%. North Africa accounts for 55 % of global dust emissions with only 8% being anthropogenic,...

  8. african mineral dust: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Laurent 19 Does the size distribution of mineral dust aerosols depend on the wind speed at emission? CERN Preprints Summary: The size distribution of mineral dust aerosols...

  9. airborne dust samples: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    which best describe the dust environment: dust loss rates, ejection velocities, and size distribution of particles. On the other hand, we use a numerical integrator to study...

  10. Dust Emission from the Perseus Molecular Cloud

    E-Print Network [OSTI]

    S. Schnee; J. Li; A. A. Goodman; A. I. Sargent

    2008-05-27T23:59:59.000Z

    Using far-infrared emission maps taken by IRAS and Spitzer and a near-infrared extinction map derived from 2MASS data, we have made dust temperature and column density maps of the Perseus molecular cloud. We show that the emission from transiently heated very small grains and the big grain dust emissivity vary as a function of extinction and dust temperature, with higher dust emissivities for colder grains. This variable emissivity can not be explained by temperature gradients along the line of sight or by noise in the emission maps, but is consistent with grain growth in the higher density and lower temperature regions. By accounting for the variations in the dust emissivity and VSG emission, we are able to map the temperature and column density of a nearby molecular cloud with better accuracy than has previously been possible.

  11. Matter Field, Dark Matter and Dark Energy

    E-Print Network [OSTI]

    Masayasu Tsuge

    2009-03-24T23:59:59.000Z

    A model concerning particle theory and cosmology is proposed. Matter field, dark matter and dark energy are created by an energy flow from space to primordial matter fields at the phase transition in the early universe.

  12. Cross-shift peak expiratory flow changes are unassociated with respirable coal dust exposure among South African coal miners

    SciTech Connect (OSTI)

    Naidoo, R.N.; Robins, T.G.; Becklake, M.; Seixas, N.; Thompson, M.L. [University of KwaZulu Natal, Durban (South Africa)

    2007-12-15T23:59:59.000Z

    he objectives of this study were to determine whether cross-shift changes in peak expiratory flow rate (PEFR) were related to respirable dust exposure in South African coalminers. Fifty workers were randomly selected from a cohort of 684 miners from 3 bituminous coal mines in Mpumalanga, South Africa. Peak expiratory efforts were measured prior to the commencement of the shift, and at the end of the shift on at least two occasions separated by at least 2 weeks, with full shift personal dust sampling being conducted on each occasion for each participant. Interviews were conducted, work histories were obtained and cumulative exposure estimates were constructed. Regression models examined the associations of cross-shift changes in PEFR with current and cumulative exposure, controlling for shift, smoking and past history of tuberculosis. There were marginal differences in cross-shift PEFR (ranging from 0.1 to 2 L/min). Linear regression analyses showed no association between cross-shift change in PEFR and current or cumulative exposure. The specific shift worked by participants in the study showed no effect. Our study showed no association between current respirable dust exposure and cross-shift changes in PEFR. There was a non-significant protective effect of cumulative dust exposure on the outcome, suggesting the presence of a 'healthy worker survivor effect' in this data.

  13. Dust Combustion Safety Issues for Fusion Applications

    SciTech Connect (OSTI)

    L. C. Cadwallader

    2003-05-01T23:59:59.000Z

    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.

  14. SPARCLE: Electrostatic Tool for Lunar Dust Control

    SciTech Connect (OSTI)

    Clark, P. E.; Curtis, S. A.; Minetto, F.; Cheung, C. Y.; Keller, J. F.; Moore, M.; Calle, C. I. [Catholic University of America Washington DC located at Code 695 NASA/GSFC Greenbelt, MD 20771 (United States); NASA/GSFC Greenbelt, MD 20771 (United States); Code KT-E NASA/KSC Cape Kennedy, FL 32899 (United States)

    2009-03-16T23:59:59.000Z

    Successful exploration of most planetary surfaces, with their impact-generated dusty regoliths, will depend on the capabilities to keep surfaces free of the dust which could compromise performance and to collect dust for characterization. Solving the dust problem is essential before we return to the Moon. During the Apollo missions, the discovery was made that regolith fines, or dust, behaved like abrasive velcro, coating surfaces, clogging mechanisms, and making movement progressively more difficult as it was mechanically stirred up during surface operations, and abrading surfaces, including spacesuits, when attempts were made to remove it manually. In addition, some of the astronauts experienced breathing difficulties when exposed to dust that got into the crew compartment. The successful strategy will deal with dust dynamics resulting from interaction between mechanical and electrostatic forces. Here we will describe the surface properties of dust particles, the basis for their behavior, and an electrostatically-based approach and methodology for addressing this issue confirmed by our preliminary results. Our device concept utilizes a focused electron beam to control the electrostatic potential of the surface. A plate of the opposite potential is then used to induce dust migration in the presence of an electrical field. Our goal is a compact device of <5 kg mass and using <5 watts of power to be operational in <5 years with heritage from ionic sweepers for active spacecraft potential control (e.g., on POLAR). Rovers could be fitted with devices that could harness the removal of dust for sampling as part of the extended exploration process on Mercury, Mars, asteroids or outer solar system satellites, as well as the Moon.

  15. Residual dust charges in discharge afterglow

    SciTech Connect (OSTI)

    Coueedel, L.; Mikikian, M.; Boufendi, L.; Samarian, A. A. [GREMI - Groupe de Recherches sur l'Energetique des Milieux Ionises, CNRS/Universite d'Orleans, 14 rue d'Issoudun, 45067 Orleans Cedex 2 (France); School of Physics A28, University of Sydney, NSW 2006 (Australia)

    2006-08-15T23:59:59.000Z

    An on-ground measurement of dust-particle residual charges in the afterglow of a dusty plasma was performed in a rf discharge. An upward thermophoretic force was used to balance the gravitational force. It was found that positively charged, negatively charged, and neutral dust particles coexisted for more than 1 min after the discharge was switched off. The mean residual charge for 200-nm-radius particles was measured. The dust particle mean charge is about -5e at a pressure of 1.2 mbar and about -3e at a pressure of 0.4 mbar.

  16. Radiation and Dynamics of Dust Particle

    E-Print Network [OSTI]

    Jozef Klacka

    2002-09-23T23:59:59.000Z

    Relativistically covariant form of equation of motion for arbitrarily shaped dust particle (neutral in charge) under the action of electromagnetic radiation is derived -- emission, scattering and absorption of radiation is considered. The result is presented in the form of optical quantities used in optics of dust particles. The obtained equation of motion represents a generalization of the Poynting-Robertson (P-R) effect, which is standardly used in orbital evolution of dust particles in astrophysics. Simultaneous action of electromagnetic radiation and gravitational fields of the central body -- star -- on the motion of the particle is discussed.

  17. Dust-Plasma Sheath in an Oblique Magnetic Field

    SciTech Connect (OSTI)

    Foroutan, G.; Mehdipour, H. [Physics Department, Faculty of Science, Sahand University of Technology, Tabriz (Iran, Islamic Republic of)

    2008-09-07T23:59:59.000Z

    Using numerical simulations of the multi fluid equations the structure of the magnetized sheath near a plasma boundary is studied in the presence of charged dust particles. The dependence of the electron, ion, and dust densities as well as the electrostatic potential, dust charge, and ion normal velocity, on the magnetic field strength and the edge dust number density is investigated.

  18. Dust-Acoustic Waves: Visible Sound Waves Robert L. Merlino

    E-Print Network [OSTI]

    Merlino, Robert L.

    Dust-Acoustic Waves: Visible Sound Waves Robert L. Merlino Department of Physics and Astronomy with their announcement that: "We find that a new type of sound wave, namely, the dust-acoustic waves, can appear" [1 and experimental work on dust acoustic waves is given. The basic physics of the dust acoustic wave and some

  19. Silica dust control when drilling concrete Page 1 of 2

    E-Print Network [OSTI]

    Knowles, David William

    Silica dust control when drilling concrete Page 1 of 2 Drilling into concrete releases a fine sandy and routinely drill into concrete are at risk of developing this disease. Controlling the dust Hammer drills are available with attached dust removal systems. These draw dust from the drill end, down the attachment

  20. GLOBAL SCALE ATTRIBUTION OF ANTHROPOGENIC AND NATURAL DUST

    E-Print Network [OSTI]

    -scale convective processes producing dust via cold pool (ha- boob) events frequent in monsoon regimes. 1

  1. Morphological Investigations of Fibrogenic Action of Estonian Oil Shale Dust

    E-Print Network [OSTI]

    V. A. Kung

    dust produced in the mining and processing of Estonian oil shale is given. Histological examination of

  2. Measured and Modeled Humidification Factors of Fresh Smoke Particles...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Measured and Modeled Humidification Factors of Fresh Smoke Particles From Biomass Burning: Role of Inorganic Constituents. Measured and Modeled Humidification Factors of Fresh...

  3. adult smoking trends: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    incorporation of flame retardants (FRs) prsents th advantage of reducing th fire hazard Paris-Sud XI, Universit de 286 Casualties and smoke emissions from...

  4. Data Acquisition-Manipulation At Valley Of Ten Thousand Smokes...

    Open Energy Info (EERE)

    Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Data Acquisition-Manipulation At Valley Of Ten Thousand Smokes Region Area (Kodosky & Keith,...

  5. adolescent smoking cessation: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Cindy 12 Attitudes toward the integration of smoking cessation treatment into drug abuse clinics. University of California eScholarship Repository Summary: staff attitudes...

  6. ahcpr smoking cessation: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Cindy 12 Attitudes toward the integration of smoking cessation treatment into drug abuse clinics. University of California eScholarship Repository Summary: staff attitudes...

  7. Water Sampling At Valley Of Ten Thousand Smokes Region Area ...

    Open Energy Info (EERE)

    Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Water Sampling At Valley Of Ten Thousand Smokes Region Area (Keith, Et Al., 1992)...

  8. Canadian Expert Panel on Tobacco Smoke and Breast Cancer Risk

    E-Print Network [OSTI]

    2009-01-01T23:59:59.000Z

    cigarette smoking, and the risk of breast cancer. Cancerand breast cancer risk. JAMA Ambrosone, C.B. , Kropp, S. ,genotypes, and breast cancer risk: pooled analysis and meta-

  9. Global coherence of dust density waves

    SciTech Connect (OSTI)

    Killer, Carsten; Melzer, André [Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald (Germany)

    2014-06-15T23:59:59.000Z

    The coherence of self-excited three-dimensional dust density waves has been experimentally investigated by comparing global and local wave properties. For that purpose, three-dimensional dust clouds have been confined in a radio frequency plasma with thermophoretic levitation. Global wave properties have been measured from the line-of-sight integrated dust density obtained from homogenous light extinction measurements. Local wave properties have been obtained from thin, two-dimensional illuminated laser slices of the cloud. By correlating the simultaneous global and local wave properties, the spatial coherence of the waves has been determined. We find that linear waves with small amplitudes tend to be fragmented, featuring an incoherent wave field. Strongly non-linear waves with large amplitudes, however, feature a strong spatial coherence throughout the dust cloud, indicating a high level of synchronization.

  10. The interstellar cold dust observed by COBE

    E-Print Network [OSTI]

    G. Lagache; A. Abergel; F. Boulanger; J. L. Puget

    1998-12-30T23:59:59.000Z

    Using DIRBE and FIRAS maps at high latitude ($|b|>10^{\\circ}$) we derive the spatial distribution of the dust temperature associated with the diffuse cirrus and the dense molecular clouds. For a $\

  11. Surface acoustic wave dust deposition monitor

    DOE Patents [OSTI]

    Fasching, G.E.; Smith, N.S. Jr.

    1988-02-12T23:59:59.000Z

    A system is disclosed for using the attenuation of surface acoustic waves to monitor real time dust deposition rates on surfaces. The system includes a signal generator, a tone-burst generator/amplifier connected to a transmitting transducer for converting electrical signals into acoustic waves. These waves are transmitted through a path defining means adjacent to a layer of dust and then, in turn, transmitted to a receiving transducer for changing the attenuated acoustic wave to electrical signals. The signals representing the attenuated acoustic waves may be amplified and used in a means for analyzing the output signals to produce an output indicative of the dust deposition rates and/or values of dust in the layer. 8 figs.

  12. Boll Weevil Control by Airplane Dusting.

    E-Print Network [OSTI]

    Thomas, F. L. (Frank Lincoln)

    1929-01-01T23:59:59.000Z

    EXPERIMENT STATIGH LiBRl BUILDINC XAS AGRICULTURAL EXPERIMENT STATION A. B. CONNER, DIRECTOR COLLEGE STATION, BRAZOS COUNTY. TEXAS FIN NO. 394 APRIL, 1929 DIVISION OF ENTOMOLOGY BOLL WEEVIL CONTROL BY AIR- PLANE DUSTING - A...~on with the School of Agriculture. rrjshand. unty: tv: SYNOPSIS The cotton acreage in Texas which has been protected against insects by airplane dusting increased from 3,000 acres in 1925 to approximateljr 50,000 acres in 1928, according to information...

  13. Transparent self-cleaning dust shield

    DOE Patents [OSTI]

    Mazumder, Malay K.; Sims, Robert A.; Wilson, James D.

    2005-06-28T23:59:59.000Z

    A transparent electromagnetic shield to protect solar panels and the like from dust deposition. The shield is a panel of clear non-conducting (dielectric) material with embedded parallel electrodes. The panel is coated with a semiconducting film. Desirably the electrodes are transparent. The electrodes are connected to a single-phase AC signal or to a multi-phase AC signal that produces a travelling electromagnetic wave. The electromagnetic field produced by the electrodes lifts dust particles away from the shield and repels charged particles. Deposited dust particles are removed when the electrodes are activated, regardless of the resistivity of the dust. Electrostatic charges on the panel are discharged by the semiconducting film. When used in conjunction with photovoltaic cells, the power for the device may be obtained from the cells themselves. For other surfaces, such as windshields, optical windows and the like, the power must be derived from an external source. One embodiment of the invention employs monitoring and detection devices to determine when the level of obscuration of the screen by dust has reached a threshold level requiring activation of the dust removal feature.

  14. Thermo-Oxidation of Tokamak Carbon Dust

    SciTech Connect (OSTI)

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

    2008-04-01T23:59:59.000Z

    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.

  15. Volcanic loading: The dust veil index

    SciTech Connect (OSTI)

    Lamb, H.H. [Univ. of East Anglia, Norwich (United Kingdom). Climatic Research Unit

    1985-09-01T23:59:59.000Z

    Dust ejected into the high atmosphere during explosive volcanic eruptions has been considered as a possible cause for climatic change. Dust veils created by volcanic eruptions can reduce the amount of light reaching the Earth`s surface and can cause reductions in surface temperatures. These climatic effects can be seen for several years following some eruptions and the magnitude and duration of the effects depend largely on the density or amount of tephra (i.e. dust) ejected, the latitude of injection, and atmospheric circulation patterns. Lamb (1970) formulated the Dust Veil Index (DVI) in an attempt to quantify the impact on the Earth`s energy balance of changes in atmospheric composition due to explosive volcanic eruptions. The DVI is a numerical index that quantifies the impact on the Earth`s energy balance of changes in atmospheric composition due to explosive volcanic eruptions. The DVI is a numerical index that quantifies the impact of a particular volcanic eruptions release of dust and aerosols over the years following the event. The DVI for any volcanic eruptions are available and have been used in estimating Lamb`s dust veil indices.

  16. Electrostatic charging of lunar dust

    SciTech Connect (OSTI)

    Walch, Bob [Department of Physics, University of Northern Colorado, Greeley, Colorado 80639 (United States); Horanyi, Mihaly [LASP, University of Colorado, Boulder, Colorado 80309-0392 (United States); Robertson, Scott [Department of Physics, University of Colorado, Boulder, Colorado 80309-0391 (United States)

    1998-10-21T23:59:59.000Z

    Transient dust clouds suspended above the lunar surface were indicated by the horizon glow observed by the Surveyor spacecrafts and the Lunar Ejecta and Meteorite Experiment (Apollo 17), for example. The theoretical models cannot fully explain these observations, but they all suggest that electrostatic charging of the lunar surface due to exposure to the solar wind plasma and UV radiation could result in levitation, transport and ejection of small grains. We report on our experimental studies of the electrostatic charging properties of an Apollo-17 soil sample and two lunar simulants MLS-1 and JSC-1. We have measured their charge after exposing individual grains to a beam of fast electrons with energies in the range of 20{<=}E{<=}90 eV. Our measurements indicate that the secondary electron emission yield of the Apollo-17 sample is intermediate between MLS-1 and JSC-1, closer to that of MLS-1. We will also discuss our plans to develop a laboratory lunar surface model, where time dependent illumination and plasma bombardment will closely emulate the conditions on the surface of the Moon.

  17. HEAVY DUST OBSCURATION OF z = 7 GALAXIES IN A COSMOLOGICAL HYDRODYNAMIC SIMULATION

    SciTech Connect (OSTI)

    Kimm, Taysun; Cen, Renyue [Department of Astrophysical Sciences, Princeton University, Peyton Hall, Princeton, NJ 08544 (United States)

    2013-10-10T23:59:59.000Z

    Hubble Space Telescope observations with the Wide Field Camera 3/Infrared reveal that galaxies at z ? 7 have very blue ultraviolet (UV) colors, consistent with these systems being dominated by young stellar populations with moderate or little attenuation by dust. We investigate UV and optical properties of the high-z galaxies in the standard cold dark matter model using a high-resolution adaptive mesh refinement cosmological hydrodynamic simulation. For this purpose, we perform panchromatic three-dimensional dust radiative transfer calculations on 198 galaxies of stellar mass 5 × 10{sup 8}-3 × 10{sup 10} M{sub ?} with three parameters: the dust-to-metal ratio, the extinction curve, and the fraction of directly escaped light from stars (f{sub esc}). Our stellar mass function is found to be in broad agreement with Gonzalez et al., independent of these parameters. We find that our heavily dust-attenuated galaxies (A{sub V} ? 1.8) can also reasonably match modest UV-optical colors, blue UV slopes, as well as UV luminosity functions, provided that a significant fraction (?10%) of light directly escapes from them. The observed UV slope and scatter are better explained with a Small-Magellanic-Cloud-type extinction curve, whereas a Milky-Way-type curve also predicts blue UV colors due to the 2175 Å bump. We expect that upcoming observations by the Atacama Large Millimeter/submillimeter Array will be able to test this heavily obscured model.

  18. PMR2088D September 2012 Smoke Sensitive Areas 2

    E-Print Network [OSTI]

    Koford, Rolf R.

    locations commonly have managed ventilation systems that could intake smoke. Larger urban areas are often, and local regulatory authorities. Iowa's rural landscape contains many similar smoke sensitive areas encountered in more typically urban settings. Managed ventilation systems are commonplace on most modern

  19. University of Michigan campuses are smoke-free environments,

    E-Print Network [OSTI]

    Eustice, Ryan

    University of Michigan campuses are smoke-free environments, both indoors and outdoors. A smoke) 936-5988 THE REGENTS OF THE UNIVERSITY OF MICHIGAN Julia Donovan Darlow, Ann Arbor Laurence B. Deitch Mary Sue Coleman, ex officio © 2011 Regents of the University of Michigan. The University of Michigan

  20. Dust Formation in Milky Way-like Galaxies

    E-Print Network [OSTI]

    McKinnon, Ryan; Vogelsberger, Mark

    2015-01-01T23:59:59.000Z

    We introduce a dust model for cosmological simulations implemented in the moving-mesh code AREPO and present a suite of cosmological hydrodynamical zoom-in simulations to study dust formation within galactic haloes. Our model accounts for the stellar production of dust, accretion of gas-phase metals onto existing grains, destruction of dust through local supernova activity, and dust driven by winds from star-forming regions. We find that accurate stellar and active galactic nuclei feedback is needed to reproduce the observed dust-metallicity relation and that dust growth largely dominates dust destruction. Our simulations predict a dust content of the interstellar medium which is consistent with observed scaling relations at $z = 0$, including scalings between dust-to-gas ratio and metallicity, dust mass and gas mass, dust-to-gas ratio and stellar mass, and dust-to-stellar mass ratio and gas fraction. We find that roughly two-thirds of dust at $z = 0$ originated from Type II supernovae, with the contribution ...

  1. Electrostatic Dust Detection and Removal for ITER

    SciTech Connect (OSTI)

    C.H. Skinner; A. Campos; H. Kugel; J. Leisure; A.L. Roquemore; S. Wagner

    2008-09-01T23:59:59.000Z

    We present some recent results on two innovative applications of microelectronics technology to dust inventory measurement and dust removal in ITER. A novel device to detect the settling of dust particles on a remote surface has been developed in the laboratory. A circuit board with a grid of two interlocking conductive traces with 25 ?m spacing is biased to 30 – 50 V. Carbon particles landing on the energized grid create a transient short circuit. The current flowing through the short circuit creates a voltage pulse that is recorded by standard nuclear counting electronics and the total number of counts is related to the mass of dust impinging on the grid. The particles typically vaporize in a few seconds restoring the previous voltage standoff. Experience on NSTX however, showed that in a tokamak environment it was still possible for large particles or fibers to remain on the grid causing a long term short circuit. We report on the development of a gas puff system that uses helium to clear such particles. Experiments with varying nozzle designs, backing pressures, puff durations, and exit flow orientations have given an optimal configuration that effectively removes particles from an area up to 25 cm² with a single nozzle. In a separate experiment we are developing an advanced circuit grid of three interlocking traces that can generate a miniature electrostatic traveling wave for transporting dust to a suitable exit port. We have fabricated such a 3-pole circuit board with 25 micron insulated traces that operates with voltages up to 200 V. Recent results showed motion of dust particles with the application of only 50 V bias voltage. Such a device could potentially remove dust continuously without dedicated interventions and without loss of machine availability for plasma operations.

  2. Large amplitude dust-acoustic solitary waves in electron-positron-ion plasma with dust grains

    SciTech Connect (OSTI)

    Esfandyari-Kalejahi, A.; Afsari-Ghazi, M.; Noori, K.; Irani, S. [Department of Physics, Faculty of Science, Azarbaijan University of Shahid Madani, 51745-406, Tabriz (Iran, Islamic Republic of)

    2012-08-15T23:59:59.000Z

    Propagation of large amplitude dust-acoustic (DA) solitary waves is investigated in electron-positron-ion plasmas in the presence of dust grains using Sagdeev potential method. It is shown that acceptable values of Mach number for propagation of the large amplitude DA solitary waves depend strongly on plasma parameters. It is also observed that the amplitude of DA solitary waves increases as both the Mach number M and dust charge Z{sub d} are increased. Furthermore, it is found that a dusty plasma with inertial dust fluid and Boltzmann distributed electrons, positrons, and ions admits only negative solitary potentials associated with nonlinear dust-acoustic waves. In addition, it is remarked that the formation of double layers is not possible in this plasma system.

  3. Cosmology with a stiff matter era

    E-Print Network [OSTI]

    Pierre-Henri Chavanis

    2014-11-27T23:59:59.000Z

    We provide a simple analytical solution of the Friedmann equations for a universe made of stiff matter, dust matter, and dark energy. A stiff matter era is present in the cosmological model of Zel'dovich (1972) where the primordial universe is assumed to be made of a cold gas of baryons. It also occurs in certain cosmological models where dark matter is made of relativistic self-gravitating Bose-Einstein condensates (BECs). When the energy density of the stiff matter is positive, the primordial universe is singular. It starts from a state with a vanishing scale factor and an infinite density. We consider the possibility that the energy density of the stiff matter is negative (anti-stiff matter). This happens, for example, when the BECs have an attractive self-interaction. In that case, the primordial universe is non-singular. It starts from a state in which the scale factor is finite and the energy density is equal to zero. For the sake of generality, we consider a cosmological constant of arbitrary sign. When the cosmological constant is positive, the universe asymptotically reaches a de Sitter phase where the scale factor increases exponentially rapidly. This can account for the accelerating expansion of the universe that we observe at present. When the cosmological constant is negative (anti-de Sitter), the evolution of the universe is cyclic. Therefore, depending on the sign of the energy density of the stiff matter and of the dark energy, we obtain singular and non-singular expanding or cyclic universes.

  4. Measurements of the Effects of Smoke on Active Circuits

    SciTech Connect (OSTI)

    Tanaka, T.J.

    1999-02-09T23:59:59.000Z

    Smoke has long been recognized as the most common source of fire damage to electrical equipment; however, most failures have been analyzed after the fire was out and the smoke vented. The effects caused while the smoke is still in the air have not been explored. Such effects have implications for new digital equipment being installed in nuclear reactors. The U.S. Nuclear Regulatory Commission is sponsoring work to determine the impact of smoke on digital instrumentation and control. As part of this program, Sandia National Laboratories has tested simple active circuits to determine how smoke affects them. These tests included the study of three possible failure modes on a functional board: (1) circuit bridging, (2) corrosion (metal loss), and (3) induction of stray capacitance. The performance of nine different circuits was measured continuously on bare and conformably coated boards during smoke exposures lasting 1 hour each and continued for 24 hours after the exposure started. The circuit that was most affected by smoke (100% change in measured values) was the one most sensitive to circuit bridging. Its high impedance (50 M{Omega}) was shorted during the exposure, but in some cases recovered after the smoke was vented. The other two failure modes, corrosion and induced stray capacitance, caused little change in the function of the circuits. The smoke permanently increased resistance of the circuit tested for corrosion, implying that the cent acts were corroded. However, the change was very small (< 2%). The stray-capacitance test circuit showed very little change after a smoke exposure in either the short or long term. The results of the tests suggest that conformal coatings and type of circuit are major considerations when designing digital circuitry to be used in critical control systems.

  5. Matter Wave Radiation Leading to Matter Teleportation

    E-Print Network [OSTI]

    Yong-Yi Huang

    2015-02-12T23:59:59.000Z

    The concept of matter wave radiation is put forward, and its equation is established for the first time. The formalism solution shows that the probability density is a function of displacement and time. A free particle and a two-level system are reinvestigated considering the effect of matter wave radiation. Three feasible experimental designs, especially a modified Stern-Gerlach setup, are proposed to verify the existence of matter wave radiation. Matter wave radiation effect in relativity has been formulated in only a raw formulae, which offers another explanation of Lamb shift. A possible mechanics of matter teleportation is predicted due to the effect of matter wave radiation.

  6. Morphology and kinematics of HI in dust-lane elliptical galaxies

    E-Print Network [OSTI]

    Raffaella Morganti; Tom Oosterloo; Elaine Sadler; Daniela Vergani

    1998-09-07T23:59:59.000Z

    We present the results of the HI observations of four dust-lane ellipticals. The HI detected is regularly distributed in disks or rings. Moreover, in three of the four objects we have detected a very large amount of neutral hydrogen with values of M_HI/L_B that are at the end of the distribution characteristic of ellipticals and similar to what typically found in spiral galaxies. Thus, these dust-lane ellipticals may represent the results of major mergers as seen at a late stage of the evolution. The regular HI distribution and kinematics has allowed to derive values of M/L_B~20 at distances of ~5 R_e from the centre. Evidence for an increase of the dark matter contribution at larger radii can also be derived from the flat rotation curves observed in some of the observed galaxies.

  7. Flammability limits of dusts: Minimum inerting concentrations

    SciTech Connect (OSTI)

    Dastidar, A.G.; Amyotte, P.R. [Dalhousie Univ., Halifax, Nova Scotia (Canada). Dept. of Chemical Engineering] [Dalhousie Univ., Halifax, Nova Scotia (Canada). Dept. of Chemical Engineering; Going, J.; Chatrathi, K. [Fike Corp., Blue Springs, MO (United States)] [Fike Corp., Blue Springs, MO (United States)

    1999-05-01T23:59:59.000Z

    A new flammability limit parameter has been defined as the Minimum Inerting Concentration (MIC). This is the concentration of inertant required to prevent a dust explosion regardless of fuel concentration. Previous experimental work at Fike in a 1-m{sup 3} spherical chamber has shown this flammability limit to exist for pulverized coal dust and cornstarch. In the current work, inerting experiments with aluminum, anthraquinone and polyethylene dusts as fuels were performed, using monoammonium phosphate and sodium bicarbonate as inertants. The results show that an MIC exists only for anthraquinone inerted with sodium bicarbonate. The other combustible dust and inertant mixtures did not show a definitive MIC, although they did show a strong dependence between inerting level and suspended fuel concentration. As the fuel concentration increased, the amount of inertant required to prevent an explosion decreased. Even though a definitive MIC was not found for most of the dusts an effective MIC can be estimated from the data. The use of MIC data can aid in the design of explosion suppression schemes.

  8. Extended silicate dust emission in PG QSOs

    E-Print Network [OSTI]

    M. Schweitzer; B. Groves; H. Netzer; D. Lutz; E. Sturm; A. Contursi; R. Genzel; L. J. Tacconi; S. Veilleux; D. -C. Kim; D. Rupke; A. J. Baker

    2008-01-30T23:59:59.000Z

    This paper addresses the origin of the silicate emission observed in PG QSOs, based on observations with the Spitzer Space Telescope. Scenarios based on the unified model suggest that silicate emission in AGN arises mainly from the illuminated faces of the clouds in the torus at temperatures near sublimation. However, detections of silicate emission in Type 2 QSOs, and the estimated cool dust temperatures, argue for a more extended emission region.To investigate this issue we present the mid-infrared spectra of 23 QSOs. These spectra, and especially the silicate emission features at ~10 and ~18 mu can be fitted using dusty narrow line region (NLR) models and a combination of black bodies. The bolometric luminosities of the QSOs allow us to derive the radial distances and covering factors for the silicate-emitting dust. The inferred radii are 100-200 times larger than the dust sublimation radius, much larger than the expected dimensions of the inner torus. Our QSO mid-IR spectra are consistent with the bulk of the silicate dust emission arising from the dust in the innermost parts of the NLR.

  9. Dust Studies in DIII-D and TEXTOR

    SciTech Connect (OSTI)

    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

    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.

  10. Baryonic matter and beyond

    E-Print Network [OSTI]

    Kenji Fukushima

    2014-10-01T23:59:59.000Z

    We summarize recent developments in identifying the ground state of dense baryonic matter and beyond. The topics include deconfinement from baryonic matter to quark matter, a diquark mixture, topological effect coupled with chirality and density, and inhomogeneous chiral condensates.

  11. Cold condensation of dust in the ISM

    E-Print Network [OSTI]

    Rouillé, Gaël; Krasnokutski, Serge A; Krebsz, Melinda; Henning, Thomas

    2015-01-01T23:59:59.000Z

    The condensation of complex silicates with pyroxene and olivine composition at conditions prevailing in molecular clouds has been experimentally studied. For this purpose, molecular species comprising refractory elements were forced to accrete on cold substrates representing the cold surfaces of surviving dust grains in the interstellar medium. The efficient formation of amorphous and homogeneous magnesium iron silicates at temperatures of about 12 K has been monitored by IR spectroscopy. The gaseous precursors of such condensation processes in the interstellar medium are formed by erosion of dust grains in supernova shock waves. In the laboratory, we have evaporated glassy silicate dust analogs and embedded the released species in neon ice matrices that have been studied spectroscopically to identify the molecular precursors of the condensing solid silicates. A sound coincidence between the 10 micron band of the interstellar silicates and the 10 micron band of the low-temperature siliceous condensates can be...

  12. Oblique interactions of dust density waves

    SciTech Connect (OSTI)

    Wang, Zhelchui [Los Alamos National Laboratory; Li, Yang - Fang [MAX-PLANCK INSTITUTE; Hou, Lujing [MAX-PLANCK INSTITUTE; Jiang, Ke [MAX-PLANCK INSTITUTE; Wu, De - Jin [CHINA; Thomas, Hubertus M [MAX-PLANCK INSTITUTE; Morfill, Gregor E [MAX-PLANCK INSTITUTE

    2010-01-01T23:59:59.000Z

    Self-excited dust density waves (DDWs) are studied in a striped electrode device. In addition to the usual perpendicularly (with respect to the electrode) propagating DDWs, which have been frequently observed in dusty plasma experiments on the ground, a low-frequency oblique mode is also observed. This low-frequency oblique DDW has a frequency much lower than the dust plasma frequency and its spontaneous excitation is observed even with a very low dust density. It is found that the low-frequency oblique mode can exist either separately or together with the usual perpendicular mode. In the latter case, a new mode arises as a result of the interactions between the perpendicular and the oblique modes. The experiments show that these three modes satisfy the wave coupling conditions in both the frequencies and the wave-vectors.

  13. Electric Dipole Radiation from Spinning Dust Grains

    E-Print Network [OSTI]

    B. T. Draine; A. Lazarian

    1998-02-18T23:59:59.000Z

    We discuss the rotational excitation of small interstellar grains and the resulting electric dipole radiation from spinning dust. Attention is given to excitation and damping of rotation by: collisions with neutrals; collisions with ions; plasma drag; emission of infrared radiation; emission of microwave radiation; photoelectric emission; and formation of H_2 on the grain surface. We introduce dimensionless functions F and G which allow direct comparison of the contributions of different mechanisms to rotational drag and excitation. Emissivities are estimated for dust in different phases of the interstellar medium, including diffuse HI, warm HI, low-density photoionized gas, and cold molecular gas. Spinning dust grains can explain much, and perhaps all, of the 14-50 GHz background component recently observed in CBR studies. It should be possible to detect rotational emission from small grains by ground-based observations of molecular clouds.

  14. Photolysis of smoke dyes on soils

    SciTech Connect (OSTI)

    Adams, R.L. (Technology Applications Inc., Athens, GA (United States). Environmental Research Lab.); Weber, E.J.; Baughman, G.L. (Environmental Protection Agency, Athens, GA (United States). Environmental Research Lab.)

    1994-06-01T23:59:59.000Z

    Photolysis of an azo, a quinophthalone, and several anthraquinone smoke dyes was studied on soil surfaces. Initially, rapid photodegradation of each dye occurred, followed by a period of much slower rate of loss, indicating that the remaining fraction of the dye was photochemically protected. The average mean depths of photolysis ranged from 0.33 to 0.68 mm for outdoor studies and from 0.42 to 0.73 mm for lab studies. The magnitude of the mean depths of photolysis suggests that photo-degradation of the dyes occurs through indirect photochemical processes. Photolysis products for only two of the dyes could be identified. Photolysis of Disperse Red 9 resulted in the formation of 1-aminoanthraquinone, whereas Solvent Yellow 33 photo-degraded to give 2-carboxyquinoline and phthalic anhydride. Reaction mechanisms involving sensitized photo-oxidation by singlet oxygen are consistent with the formation of these reaction products.

  15. Design of a new cotton dust sampler

    E-Print Network [OSTI]

    Hickman, Phillip Dean

    1985-01-01T23:59:59.000Z

    DESIGN OF A NEW COTTON DUST SAMPLER A Thesis by PHILLIP DEAN HICKMAN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1985 Major Subject...: Agricultural Engineering DESIGN OF A NEW COTTON DUST SAMPLER A Thesis by PHILLIP DEAN HICKMAN Approved as to style and content by: Calvin B. Parnell, Jr. (Chairman of Committee) 0. R. Kunze (Member) Andrew R. McFarland (Member) Ric ard B. nz (Memb...

  16. Algebraically general, gravito-electric rotating dust

    E-Print Network [OSTI]

    Lode Wylleman

    2008-06-17T23:59:59.000Z

    The class of gravito-electric, algebraically general, rotating `silent' dust space-times is studied. The main invariant properties are deduced. The number $t_0$ of functionally independent zero-order Riemann invariants satisfies $1\\leq t_0\\leq 2$ and special attention is given to the subclass $t_0=1$. Whereas there are no $\\Lambda$-term limits comprised in the class, the limit for vanishing vorticity leads to two previously derived irrotational dust families with $\\Lambda>0$, and the shear-free limit is the G\\"{o}del universe.

  17. Dark Matter Theory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Dark Matter Theory Dark Matter Theory Understanding discoveries at the Energy, Intensity, and Cosmic Frontiers Get Expertise Rajan Gupta (505) 667-7664 Email Bruce Carlsten (505)...

  18. Global observations of desert dust and biomass burning aerosols

    E-Print Network [OSTI]

    Graaf, Martin de

    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 and desert dust observations from GOME and SCIAMACHY · Conclusions and Outlook #12; · Absorbing Aerosol

  19. aeolian dust climate: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of dust deposition, grain size, and mineralogical and chemical composition relative to climate and to type and lithology of dust source. The average silt and clay flux (rate of...

  20. Dust takes detour on ice-cloud journey | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Dust takes detour on ice-cloud journey Dust takes detour on ice-cloud journey Pollution-coated particles bypass ice formation, but influence clouds Cirrus clouds are composed of...

  1. Saharan dust particles nucleate droplets in eastern Atlantic clouds Cynthia H. Twohy,1

    E-Print Network [OSTI]

    Collett Jr., Jeffrey L.

    as CCN. Given the dual nature of Saharan dust particles as CCN and ice nuclei, this infusion of dust

  2. SMOKE-FREE POLICY This policy implements CSU Executive memorandum 02-108 in accordance with

    E-Print Network [OSTI]

    Ponce, V. Miguel

    SMOKE-FREE POLICY This policy implements CSU Executive memorandum 02-108 in accordance as a smoking area, consistent with the overall goals of this policy; smoking is prohibited in outdoor SDSU, unless designated as a smoking area. The success of this policy depends upon the thoughtfulness

  3. Policy Title: NMSU Smoking Policy Effective Date: January 1, 1986 Last Revised Date: May 9, 2006

    E-Print Network [OSTI]

    Nishiguchi, Michele

    doorways, open windows, enclosed walkways, and ventilation systems to prevent smoke from entering enclosed

  4. Information Circular 9465 Handbook for Dust Control in Mining

    E-Print Network [OSTI]

    Saylor, John R.

    .......................................................................... 11 2-1. Machine-mounted scrubber design................................................................................................................... 24 2-2. Dust scrubber used with blowing ventilation ..............................................................................

  5. SUNLIGHT TRANSMISSION THROUGH DESERT DUST AND MARINE AEROSOLS: DIFFUSE LIGHT

    E-Print Network [OSTI]

    SUNLIGHT TRANSMISSION THROUGH DESERT DUST AND MARINE AEROSOLS: DIFFUSE LIGHT CORRECTIONS TO SUN transmission through desert dust and marine aerosols: Diffuse light corrections to Sun photometry 2004; published 27 April 2004. [1] Desert dust and marine aerosols are receiving increased scientific

  6. Online Supplement S1.0 Dust/Climate Interactions

    E-Print Network [OSTI]

    Mahowald, Natalie

    of the dust, its vertical distribution, cloud cover, and the albedo of the underlying surface [e.g., Liao the content and mixing state of iron oxides (hematite, goethite) in dust affects its radiative effect [Sokolik radiative effect. The presence of dust in the atmosphere changes the radiation balance, with the surface

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

    SciTech Connect (OSTI)

    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

    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.

  8. USING THE X-RAY DUST SCATTERING HALO OF CYGNUS X-1 TO DETERMINE DISTANCE AND DUST DISTRIBUTIONS

    E-Print Network [OSTI]

    Xiang, Jingen

    We present a detailed study of the X-ray dust scattering halo of the black hole candidate Cygnus X-1 based on two Chandra High Energy Transmission Gratings Spectrometer observations. Using 18 different dust models, including ...

  9. Optical Properties of Saharan Dust and Asian Dust: Application to Radiative Transfer Simulations 

    E-Print Network [OSTI]

    Fang, Guangyang

    2012-07-16T23:59:59.000Z

    properties for radiative transfer simulations. Using a Rapid Radiative Transfer Model (RRTM), the radiative forcing of mineral dust was computed at both the top of the atmosphere and the surface. By analyzing samples from various in-situ measurements, we...

  10. Recycling of electric-arc-furnace dust

    SciTech Connect (OSTI)

    Sresty, G.C.

    1990-05-01T23:59:59.000Z

    Electric arc furnace (EAF) dust is one of the largest solid waste streams produced by steel mills, and is classified as a waste under the Resource Conservation and Recovery Act (RCRA) by the U.S. Environmental Protection Agency (EPA). Successful recycle of the valuable metals (iron, zinc, and lead) present in the dust will result in resource conservation while simultaneously reducing the disposal problems. Technical feasibility of a novel recycling method based on using hydrogen as the reductant was established under this project through laboratory experiments. Sponge iron produced was low in zinc, cadmium, and lead to permit its recycle, and nontoxic to permit its safe disposal as an alternative to recycling. Zinc oxide was analyzed to contain 50% to 58% zinc by weight, and can be marketed for recovering zinc and lead. A prototype system was designed to process 2.5 tons per day (600 tons/year) of EAF dust, and a preliminary economic analysis was conducted. The cost of processing dust by this recycling method was estimated to be comparable to or lower than existing methods, even at such low capacities.

  11. HOT DEBRIS DUST AROUND HD 106797

    SciTech Connect (OSTI)

    Fujiwara, Hideaki; Onaka, Takashi [Department of Astronomy, School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Yamashita, Takuya [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Ishihara, Daisuke; Kataza, Hirokazu; Ootsubo, Takafumi; Murakami, Hiroshi; Nakagawa, Takao; Hirao, Takanori; Enya, Keigo [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan); Fukagawa, Misato [Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043, Osaka (Japan); Marshall, Jonathan P.; White, Glenn J. [Department of Physics and Astronomy, The Open University, Walton Hall, Milton Keynes, MK7 6AA (United Kingdom)], E-mail: fujiwara@astron.s.u-tokyo.ac.jp

    2009-04-10T23:59:59.000Z

    Photometry of the A0 V main-sequence star HD 106797 with AKARI and Gemini/T-ReCS is used to detect excess emission over the expected stellar photospheric emission between 10 and 20 {mu}m, which is best attributed to hot circumstellar debris dust surrounding the star. The temperature of the debris dust is derived as T {sub d} {approx} 190 K by assuming that the excess emission is approximated by a single temperature blackbody. The derived temperature suggests that the inner radius of the debris disk is {approx}14 AU. The fractional luminosity of the debris disk is 1000 times brighter than that of our own zodiacal cloud. The existence of such a large amount of hot dust around HD 106797 cannot be accounted for by a simple model of the steady state evolution of a debris disk due to collisions, and it is likely that transient events play a significant role. Our data also show a narrow spectral feature between 11 and 12 {mu}m attributable to crystalline silicates, suggesting that dust heating has occurred during the formation and evolution of the debris disk of HD 106797.

  12. The general double-dust solution

    E-Print Network [OSTI]

    B. V. Ivanov

    2003-02-04T23:59:59.000Z

    The gravitational field of two identical rotating and counter-moving dust beams is found in full generality. The solution depends on an arbitrary function and a parameter. Some of its properties are studied. Previous particular solutions are derived as subcases.

  13. american stop smoking: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 HOW PEOPLE STOP SMOKING: AN EXPLORATORY STUDY University of Kansas - KU ScholarWorks Summary:...

  14. Intergalactic dust and its photoelectric heating

    E-Print Network [OSTI]

    Akio K. Inoue; Hideyuki Kamaya

    2008-10-31T23:59:59.000Z

    We have examined the dust photoelectric heating in the intergalactic medium (IGM). The heating rate in a typical radiation field of the IGM is represented by $\\Gamma_{\\rm pe} = 1.2\\times10^{-34}$ erg s$^{-1}$ cm$^{-3}$ $({\\cal D}/10^{-4})(n_{\\rm H}/10^{-5} {\\rm cm^{-3}})^{4/3} (J_{\\rm L}/10^{-21} {\\rm erg s^{-1} cm^{-2} Hz^{-1} sr^{-1}})^{2/3} (T/10^4 {\\rm K})^{-1/6}$, where ${\\cal D}$ is the dust-to-gas mass ratio, $n_{\\rm H}$ is the hydrogen number density, $J_{\\rm L}$ is the mean intensity at the hydrogen Lyman limit of the background radiation, and $T$ is the gas temperature, if we assume the new X-ray photoelectric yield model by Weingartner et al. (2006) and the dust size distribution in the Milky Way by Mathis, Rumpl, & Nordsieck (1977). This heating rate dominates the HI and HeII photoionization heating rates when the hydrogen number density is less than $\\sim10^{-6}$ cm$^{-3}$ if ${\\cal D}=10^{-4}$ which is 1% of that in the Milky Way, although the heating rate is a factor of 2--4 smaller than that with the old yield model by Weingartner & Draine (2001). The grain size distribution is very important. If only large ($\\ge0.1$ $\\mu$m) grains exist in the IGM, the heating rate is reduced by a factor of $\\simeq5$. Since the dust heating is more efficient in a lower density medium relative to the photoionization heating, it may cause an inverted temperature--density relation in the low density IGM suggested by Bolton et al. (2008). Finally, we have found that the dust heating is not very important in the mean IGM before the cosmic reionization.

  15. Dust Studies in DIII-D and TEXTOR

    SciTech Connect (OSTI)

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

    2008-10-14T23:59:59.000Z

    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. Energetic plasma disruptions produce significant amounts of dust. However, dust production by disruptions alone is insufficient to account for the estimated in-vessel dust inventory in DIII-D. 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. Migration of pre-characterized carbon dust is studied in DIII-D and TEXTOR by injecting 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. Individual dust particles are observed moving at velocities of 10-100 m/s, predominantly in the toroidal direction, consistent with the drag force from the deuteron flow and in agreement with modeling by the 3D DustT code. 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. Dust is launched either in the beginning of a discharge or at the initiation of NBI, preferentially in a direction perpendicular to the toroidal magnetic field. 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.

  16. Solar wind driven dust acoustic instability with Lorentzian kappa distribution

    SciTech Connect (OSTI)

    Arshad, Kashif [National Center for Physics (NCP), Quaid-i-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan) [National Center for Physics (NCP), Quaid-i-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Pakistan Institute of Engineering and Applied Sciences, P.O. Nilore, Islamabad and University of Wah, Wah Cantt 47040 (Pakistan); Ehsan, Zahida, E-mail: Ehsan.zahida@gmail.com [National Center for Physics (NCP), Quaid-i-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan) [National Center for Physics (NCP), Quaid-i-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Universita degli Studi del Molise, 86090 Pesche - IS (Italy); INFN Sezione di Napoli, 80126 Napoli (Italy); Department of Physics, COMSATS Institute of Information Technology (CIIT), Defence Road, Off Raiwind Road, Lahore 86090 (Pakistan); Khan, S. A. [National Center for Physics (NCP), Quaid-i-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan)] [National Center for Physics (NCP), Quaid-i-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Mahmood, S. [Theoretical Plasma Physics Division, PINSTEC, PO Box Nilore, Islamabad 44000 (Pakistan)] [Theoretical Plasma Physics Division, PINSTEC, PO Box Nilore, Islamabad 44000 (Pakistan)

    2014-02-15T23:59:59.000Z

    In a three species electron-ion-dust plasma following a generalized non-Maxwellian distribution function (Lorentzian or kappa), it is shown that a kinetic instability of dust-acoustic mode exists. The instability threshold is affected when such (quasineutral) plasma permeates through another static plasma. Such case is of interest when the solar wind is streaming through the cometary plasma in the presence of interstellar dust. In the limits of phase velocity of the waves larger and smaller than the thermal velocity of dust particles, the dispersion properties and growth rate of dust-acoustic mode are investigated analytically with validation via numerical analysis.

  17. Compositional changes in red and violet smoke mixes after combustion

    SciTech Connect (OSTI)

    Buchanan, M.V.; Rubin, I.B.; Moneyhun, J.H.

    1983-01-01T23:59:59.000Z

    Anthraquinone-derived dyes are commonly used in colored dye mixes prepared for signal smoke grenades. Biological studies have shown, however, that a number of these dyes exhibit bacterial mutagenicity. In addition, these dyes are similar in structure to several polycyclic aromatic hydrocarbons which are well-known carcinogens. The grenades contain not only anthraquinone-derived dyes, but also a pyrotechnic fuel and cooling and starting mixes consisting primarily of potassium chlorate and nitrate, sodium bicarbonate, and sulfur. These dyes are volatilized at temperatures up to 550/sup 0/C during the detonation of the grenade, which could subject the dyes to oxidative and pyrolytic reactions that could result in a variety of reaction by-products. As part of a program to investigate possible environmental and occupational risks of the colored smoke dyes and in signal grenades, two colored smoke mixes, red and violet, have been studied both before and after detonation to evaluate any differences in composition due to the combustion process. This report focuses primarily on the separation and identification of the components of the original and combusted red and violet smoke mixes. The conditions for the detonation of the smoke grenades and sampling of the combusted smoke mixes are also discussed.

  18. Harvard University recognizes that smoking is dangerous to the health of the smoker and that involuntary smoking is a cause of disease, including lung

    E-Print Network [OSTI]

    and that involuntary smoking is a cause of disease, including lung cancer, in healthy nonsmokers. The simple separation

  19. Dust en-route to Jupiter and the Galilean satellites

    E-Print Network [OSTI]

    Krüger, H; Krueger, Harald; Gruen, Eberhard

    2002-01-01T23:59:59.000Z

    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 i...

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

    E-Print Network [OSTI]

    Michael W. Regan; John S. Mulchaey

    1999-03-03T23:59:59.000Z

    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.

  1. AN INFRARED CENSUS OF DUST IN NEARBY GALAXIES WITH SPITZER (DUSTINGS). I. OVERVIEW

    SciTech Connect (OSTI)

    Boyer, Martha L.; Sonneborn, George [Observational Cosmology Laboratory, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); McQuinn, Kristen B. W.; Gehrz, Robert D.; Skillman, Evan [Minnesota Institute for Astrophysics, School of Physics and Astronomy, 116 Church Street SE, University of Minnesota, Minneapolis, MN 55455 (United States); Barmby, Pauline [Department of Physics and Astronomy, University of Western Ontario, London, ON, N6A 3K7 (Canada); Bonanos, Alceste Z. [IAASARS, National Observatory of Athens, GR-15236 Penteli (Greece); Gordon, Karl D.; Meixner, Margaret [STScI, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Groenewegen, M. A. T. [Royal Observatory of Belgium, Ringlaan 3, B-1180 Brussels (Belgium); Lagadec, Eric [Laboratoire Lagrange, UMR7293, Univ. Nice Sophia-Antipolis, CNRS, Observatoire de la Côte d'Azur, F-06300 Nice (France); Lennon, Daniel [ESA—European Space Astronomy Centre, Apdo. de Correo 78, E-28691 Villanueva de la Cañada, Madrid (Spain); Marengo, Massimo [Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Sloan, G. C. [Astronomy Department, Cornell University, Ithaca, NY 14853-6801 (United States); Van Loon, Jacco Th. [Astrophysics Group, Lennard-Jones Laboratories, Keele University, Staffordshire ST5 5BG (United Kingdom); Zijlstra, Albert, E-mail: martha.boyer@nasa.gov [Jodrell Bank Centre for Astrophysics, Alan Turing Building, University of Manchester, Manchester M13 9PL (United Kingdom)

    2015-01-01T23:59:59.000Z

    Nearby resolved dwarf galaxies provide excellent opportunities for studying the dust-producing late stages of stellar evolution over a wide range of metallicity (–2.7 ? [Fe/H] ? –1.0). Here, we describe DUSTiNGS (DUST in Nearby Galaxies with Spitzer): a 3.6 and 4.5 ?m post-cryogen Spitzer Space Telescope imaging survey of 50 dwarf galaxies within 1.5 Mpc that is designed to identify dust-producing asymptotic giant branch (AGB) stars and massive stars. The survey includes 37 dwarf spheroidal, 8 dwarf irregular, and 5 transition-type galaxies. This near-complete sample allows for the building of statistics on these rare phases of stellar evolution over the full metallicity range. The photometry is >75% complete at the tip of the red giant branch for all targeted galaxies, with the exception of the crowded inner regions of IC 10, NGC 185, and NGC 147. This photometric depth ensures that the majority of the dust-producing stars, including the thermally pulsing AGB stars, are detected in each galaxy. The images map each galaxy to at least twice the half-light radius to ensure that the entire evolved star population is included and to facilitate the statistical subtraction of background and foreground contamination, which is severe at these wavelengths. In this overview, we describe the survey, the data products, and preliminary results. We show evidence for the presence of dust-producing AGB stars in eight of the targeted galaxies, with metallicities as low as [Fe/H] = –1.9, suggesting that dust production occurs even at low metallicity.

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

    SciTech Connect (OSTI)

    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

    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 (<4%), while carbon-rich AGB stars (especially the so-called extreme AGB stars) account for 87%-89% of the total dust input from cool evolved stars. We also estimate the dust input from hot stars and supernovae (SNe), and find that if SNe produce 10{sup -3} M{sub Sun} of dust each, then the total SN dust input and AGB input are roughly equivalent. We consider several scenarios of SN dust production and destruction and find that the interstellar medium (ISM) dust can be accounted for solely by stellar sources if all SNe produce dust in the quantities seen around the dustiest examples and if most SNe explode in dense regions where much of the ISM dust is shielded from the shocks. We find that AGB stars contribute only 2.1% of the ISM dust. Without a net positive contribution from SNe to the dust budget, this suggests that dust must grow in the ISM or be formed by another unknown mechanism.

  3. Ca depletion and the presence of dust in large scale nebulosities in radiogalaxies (I)

    E-Print Network [OSTI]

    M. Villar-Martin; L. Binette

    1995-11-24T23:59:59.000Z

    We show that the study of the Calcium depletion is a valid an highly sensitive method for investigating the chemical and physical history of the very extended ionized nebulae seen around radio galaxies (EELR), massive ellipticals and `cooling flow' galaxies. By observing the near IR spectrum of nebular regions characterized by low excitation emission lines (LINER-like), we can use the intensity of the [CaII]$\\lambda\\lambda 7291,7324$\\AA\\ doublet --relative to other lines, like H$\\alpha$-- to infer the amount of Calcium depletion onto dust grains. The presence of dust in these objects --which does not necessarily result in a measurable level of extinction-- would favour a `galactic debris' rather than a `cooling flow' origin for the emitting gas. Before aplying such test to our data, we study four possible alternative mechanisms to dust depletion and which could have explained the absence of the [CaII] lines: a) ionization of Ca$^+$ from its metastable level, b) thermal ionization of Ca$^+$, c) a high ionization parameter and/or a harder ionizing contiuum than usually asummed and d) matter bounded models associated to a hard ionizing continuum. We show that none of these alternative mechanisms explain the absence of the [CaII] lines, except possibly for the highly ionized EELR where a high ionization parameter is required combined with a soft power law. We thus conclude that for the other low excitation emission regions (cooling flows, liners, low excitation EELR), the abscence of the CaII lines {\\it must} be due to the depletion of Calcium onto dust grains.

  4. Transport of dust particles in inductively coupled discharges

    SciTech Connect (OSTI)

    Hwang, H.H.; Ventzek, P.L.G.; Hoekstra, R.; Kushner, M.J. [Univ. of Illinois, Urbana, IL (United States). Dept. of Electrical and Computer Engineering

    1994-12-31T23:59:59.000Z

    Contamination by particulates, or ``dust``, in plasma processing reactors decreases the yield of microelectronic components. In low temperature plasmas, such as those used in etching or deposition reactors to fabricate semiconductor devices, the particles can form to appreciable densities. These particles can be trapped or expelled from the reactor, depending on which forces dominate their transport. Quantities that affect dust motion in Inductively Coupled Plasma (ICP) discharges are the charge of the dust particles (electrostatic forces), momentum transfer with ions (viscous ion-drag forces), temperature gradients from heated electrodes (thermophoretic forces), and gas flow (fluid drag forces). The authors have developed a 2-D Monte Carlo simulation to investigate the trajectories of dust particles in ICP reactors. The model may have an arbitrary number and variety of dust species, and different gas mixtures may be used. The self-consistent electric fields, ion energy distributions, and species densities are imported from a companion Monte Carlo-fluid hybrid model. A semi-analytic model is used to determine the dust charge as well as the momentum transfer cross sections between dust and ions. The electrode topography can also affect the trapping locations of dust. Grooves on the electrodes perturb electrical forces and heated washers can change the thermophoretic forces; hence the spatial dust density varies from the case with a smooth, nonheated electrode. These effects on particle trapping will be presented. Other factors on trapping locations, such as dust particle size and varying power flow with time, will also be discussed.

  5. Design of programmable matter

    E-Print Network [OSTI]

    Knaian, Ara N. (Ara Nerses), 1977-

    2008-01-01T23:59:59.000Z

    Programmable matter is a proposed digital material having computation, sensing, actuation, and display as continuous properties active over its whole extent. Programmable matter would have many exciting applications, like ...

  6. Asymmetric dark matter

    SciTech Connect (OSTI)

    Kumar, Jason [Department of Physics and Astronomy, University of Hawaii, Honolulu, HI 96822 (United States)

    2014-06-24T23:59:59.000Z

    We review the theoretical framework underlying models of asymmetric dark matter, describe astrophysical constraints which arise from observations of neutron stars, and discuss the prospects for detecting asymmetric dark matter.

  7. Exothermic dark matter

    E-Print Network [OSTI]

    Graham, Peter W.

    We propose a novel mechanism for dark matter to explain the observed annual modulation signal at DAMA/LIBRA which avoids existing constraints from every other dark matter direct detection experiment including CRESST, CDMS, ...

  8. Hot-dark matter, cold dark matter and accelerating universe

    E-Print Network [OSTI]

    Abbas Farmany; Amin Farmany; Mohammad Mahmoodi

    2006-07-07T23:59:59.000Z

    The Friedman equation is solved for a universe contains hotdark matter and cold dark matter. In this scenario, hot-dark matter drives an accelerating universe no cold dark matter.

  9. Old supernova dust factory revealed at the Galactic center

    E-Print Network [OSTI]

    Lau, Ryan M; Morris, Mark R; Li, Zhiyuan; Adams, Joseph D

    2015-01-01T23:59:59.000Z

    Dust formation in supernova ejecta is currently the leading candidate to explain the large quantities of dust observed in the distant, early Universe. However, it is unclear whether the ejecta-formed dust can survive the hot interior of the supernova remnant (SNR). We present infrared observations of ~0.02 $M_\\odot$ of warm (~100 K) dust seen near the center of the ~10,000 yr-old Sgr A East SNR at the Galactic center. Our findings signify the detection of dust within an older SNR that is expanding into a relatively dense surrounding medium ($n_e$ ~ 100 $\\mathrm{cm}^{-3}$) and has survived the passage of the reverse shock. The results suggest that supernovae may indeed be the dominant dust production mechanism in the dense environment of early Universe galaxies.

  10. The effect of dust size distribution on quantum dust acoustic wave

    SciTech Connect (OSTI)

    El-Labany, S. K.; El-Taibany, W. F.; Behery, E. E. [Department of Physics, Faculty of Science, Mansoura University, Damietta Branch, Damietta El-Gedida, P.O. 34517 (Egypt); El-Siragy, N. M. [Department of Physics, Faculty of Science, Tanta University, Tanta, P.O. 31527 (Egypt)

    2009-09-15T23:59:59.000Z

    Based on the quantum hydrodynamics theory, a proposed model for quantum dust acoustic waves (QDAWs) is presented including the dust size distribution (DSD) effect. A quantum version of Zakharov-Kuznetsov equation is derived adequate for describing QDAWs. Two different DSD functions are applied. The relevance of the wave velocity, amplitude, and width to the DSD is investigated numerically. The quantum effect changes only the soliton width. A brief conclusion is presented to the current findings and their relevance to astrophysics data is also discussed.

  11. in Condensed Matter Physics

    E-Print Network [OSTI]

    van der Torre, Leon

    Master in Condensed Matter Physics ­ Master académique #12;2 #12;3 Students at the University. Condensed matter physics is about explaining and predicting the relationship between the atomic, and broad education in the field of condensed matter physics · introduce you to current research topics

  12. Dust acoustic shock waves in two temperatures charged dusty grains

    SciTech Connect (OSTI)

    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

    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.

  13. Applications and Progress of Dust Injection to Fusion Energy

    SciTech Connect (OSTI)

    Wang Zhehui; Wurden, Glen A. [Los Alamos National Laboratory (United States); Mansfield, Dennis K.; Roquemore, Lane A. [Princeton Plasma Physics Laboratory (United States); Ticos, Catalin M. [National Institute for Laser, Plasma, and Radiation Physics, Bucharest (Romania)

    2008-09-07T23:59:59.000Z

    Three regimes of dust injection are proposed for different applications to fusion energy. In the 'low-speed' regime (<5 km/s), basic dust transport study, edge plasma diagnostics, edge-localized-mode (ELM) pacing in magnetic fusion devices can be realized by injecting dust of known properties into today's fusion experiments. ELM pacing, as an alternative to mini-pellet injection, is a promising scheme to prevent disruptions and type I ELM's that can cause catastrophic damage to fusion devices. Different schemes are available to inject dust. In the 'intermediate-speed' regime (10-200 km/s), possible applications of dust injection include fueling of the next-step fusion devices, core-diagnostics of the next-step fusion devices, and compression of plasma and solid targets to aid fusion energy production. Promising laboratory results of dust moving at 10-50 km/s do exist. Significant advance in this regime may be expected in the near term to achieve higher dust speeds. In the 'high-speed' regime (>500 km/s), dust injection can potentially be used to directly produce fusion energy through impact. Ideas on how to achieve these extremely high speeds are mostly on paper. No plan exists today to realize them in laboratory. Some experimental results, including electrostatic, electromagnetic, gas-dragged, plasma-dragged, and laser-ablation-based acceleration, are summarized and compared. Some features and limitations of the different acceleration methods will be discussed. A necessary component of all dust injectors is the dust dropper (also known as dust dispenser). A computer-controlled piezoelectric crystals has been developed to dropped dust in a systematic and reproducible manner. Particle fluxes ranges from a few tens of particles per second up to thousands of particles per second by this simple device.

  14. Smoke production from multiple nuclear explosions in nonurban areas

    SciTech Connect (OSTI)

    Small, R.D.; Bush, B.W.

    1985-08-02T23:59:59.000Z

    The amount of smoke that may be produced by wildland or rural fires as a consequence of a large-scale nuclear exchange is estimated. The calculation is based on a compilation of rural military facilities, identified from a wide variety of unclassified sources, together with data on their geographic positions, surrounding vegetation (fuel), and weather conditions. The ignition area (corrected for fuel moisture) and the amount of fire spread are used to calculate the smoke production. The results show a substantially lower estimated smoke production (from wildland fires) than in earlier nuclear winter studies. The amount varies seasonally and at its peak is less by an order of magnitude than the estimated threshold level necessary for a major attenuation of solar radiation. 32 references, 6 figures, 2 tables.

  15. Attachment of radon progeny to cigarette-smoke aerosols

    SciTech Connect (OSTI)

    Biermann, A.H.; Sawyer, S.R.

    1995-05-01T23:59:59.000Z

    The daughter products of radon gas are now recognized as a significant contributor to radiation exposure to the general public. It is also suspected that a synergistic effect exists with the combination cigarette smoking and radon exposure. We have conducted an experimental investigation to determine the physical nature of radon progeny interactions with cigarette smoke aerosols. The size distributions of the aerosols are characterized and attachment rates of radon progeny to cigarette-smoke aerosols are determined. Both the mainstream and sidestream portions of the smoke aerosol are investigated. Unattached radon progeny are very mobile and, in the presence of aerosols, readily attach to the particle surfaces. In this study, an aerosol chamber is used to contain the radon gas, progeny and aerosol mixture while allowing the attachment process to occur. The rate of attachment is dependent on the size distribution, or diffusion coefficient, of the radon progeny as well as the aerosol size distribution. The size distribution of the radon daughter products is monitored using a graded-screen diffusion battery. The diffusion battery also enables separation of the unattached radon progeny from those attached to the aerosol particles. Analysis of the radon decay products is accomplished using alpha spectrometry. The aerosols of interest are size fractionated with the aid of a differential mobility analyzer and cascade impactor. The measured attachment rates of progeny to the cigarette smoke are compared to those found in similar experiments using an ambient aerosol. The lowest attachment coefficients observed, {approximately}10{sup {minus}6} cm{sup 3}/s, occurred for the ambient aerosol. The sidestream and mainstream smoke aerosols exhibited higher attachment rates in that order. The results compared favorably with theories describing the coagulation process of aerosols.

  16. The Differential Lifetimes of Protostellar Gas and Dust Disks

    E-Print Network [OSTI]

    Taku Takeuchi; C. J. Clarke; D. N. C. Lin

    2005-03-22T23:59:59.000Z

    We construct a protostellar disk model that takes into account the combined effect of viscous evolution, photoevaporation and the differential radial motion of dust grains and gas. For T Tauri disks, the lifetimes of dust disks that are mainly composed of millimeter sized grains are always shorter than the gas disks' lifetimes, and become similar only when the grains are fluffy (density 10 AU), without strong signs of gas accretion nor of millimeter thermal emission from the dust. For Herbig AeBe stars, the strong photoevaporation clears the inner disks in 10^6 yr, before the dust grains in the outer disk migrate to the inner region. In this case, the grains left behind in the outer gas disk accumulate at the disk inner edge (at 10-100 AU from the star). The dust grains remain there even after the entire gas disk has been photoevaporated, and form a gas-poor dust ring similar to that observed around HR 4796A. Hence, depending on the strength of the stellar ionizing flux, our model predicts opposite types of products around young stars. For low mass stars with a low photoevaporation rate, dust-poor gas disks with an inner hole would form, whereas for high mass stars with a high photoevaporation rate, gas-poor dust rings would form. This prediction should be examined by observations of gas and dust around weak line T Tauri stars and evolved Herbig AeBe stars.

  17. aeolian dust archived: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    classifications of the ionizing stars to examine the role of stellar sources on dust heating and processing. Our infrared observations show surprisingly little correlation...

  18. anhydrous interplanetary dust: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    J. A. M. McDonnell; Kalle Bunte; Hakan Svedhem; Gerhard Drolshagen 2006-09-13 3 Fractal Signatures in Analogs of Interplanetary Dust Particles CERN Preprints Summary:...

  19. adiabatic dust charge: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    a transition between states. The first result Petta, Jason 12 Charging and Growth of Fractal Dust Grains CERN Preprints Summary: The structure and evolution of aggregate grains...

  20. ISM dust feedback from low to high mass stars

    E-Print Network [OSTI]

    Falceta-Goncalves; D.

    2007-10-26T23:59:59.000Z

    The dust component of the interstellar medium (ISM) has been extensively studied in the past decades. Late-type stars have been assumed as the main source of dust to the ISM, but recent observations show that supernova remnants may play a role on the ISM dust feedback. In this work, I study the importance of low and high mass stars, as well as their evolutionary phase, on the ISM dust feedback process. I also determine the changes on the obtained results considering different mass distribution functions and star formation history. We describe a semi-empirical calculation of the relative importance of each star at each evolutionary phase in the dust ejection to the ISM. I compare the obtained results for two stellar mass distribution functions, the classic Salpeter initial mass function and the present day mass function. I used the evolutionary track models for each stellar mass, and the empirical mass-loss rates and dust-to-gas ratio. The relative contribution of each stellar mass depends on the used distribution. Ejecta from massive stars represent the most important objects for the ISM dust replenishment using the Salpeter IMF. On the other hand, for the present day mass function low and intermediate mass stars are dominant. Late-type giant and supergiant stars dominate the ISM dust feedback in our actual Galaxy, but this may not the case of galaxies experiencing high star formation rates, or at high redshifts. In those cases, SNe are dominant in the dust feedback process.

  1. Secondary Electron Emission from Dust and Its Effect on Charging

    SciTech Connect (OSTI)

    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

    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.

  2. aeolian dust experiment: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    core relative to ambient, facilitating dust lifting by reducing the threshold wind speed for particle elevation. Finally, radial velocity profiles constructed from our...

  3. Applications of high-speed dust injection to magnetic fusion

    SciTech Connect (OSTI)

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

    2012-08-08T23:59:59.000Z

    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.

  4. The Unwelcome Guest: How Scotland invited the tobacco industry to smoke outside

    E-Print Network [OSTI]

    Rachel Harrison; Julia Hurst

    2005-01-01T23:59:59.000Z

    ventilation and so avoid legislation aimed at minimising smoking on their premises”ventilation could actually produce cleaner air than that in smoke-free premises.premises. The SLTA said that this, combined with efficient ventilation

  5. The Influence of Weight Concerns and Weight Control Expectancies in the Smoking Behavior of Spanish Adolescents

    E-Print Network [OSTI]

    Berrios-Hernandez, Mayra

    2012-07-16T23:59:59.000Z

    ) from schools in Alicante, Spain. The students completed questionnaires regarding smoking history and status. They also responded to questions regarding smoking expectancies and weigh concerns. Results suggested differences between smokers...

  6. Nuclear winter: Three-dimensional simulations including interactive transport, scavenging, and solar heating of smoke

    SciTech Connect (OSTI)

    Malone, R.C.; Auer, L.H.; Glatzmaier, G.A.; Wood, M.C.; Toon, O.B.

    1986-01-20T23:59:59.000Z

    We reexamine the ''nuclear winter'' hypothesis with a three-dimensional global model modified to allow for localized injection of smoke, its transport by the simulated winds, its absorption of sunlight, and its removal by model-simulated precipitation. Smoke injected into the troposphere is driven upward by solar heating. The tropopause, initially above the smoke, reforms below the heated smoke layer and separates it from precipitation below. Although much smoke is scavenged while the thermal structure is being altered, the residence time of the remaining smoke is greatly increased. We find, particularly for July conditions, a longer-lasting ''nuclear winter'' effect than was found in earlier modeling studies in which normal tropospheric residence times were assumed. In January the smaller solar flux in the northern hemisphere allows faster removal of smoke than in July. Significant cooling of the northern hemisphere continents is predicted; its dependence on season and injected smoke mass is described.

  7. Of Matters Condensed

    E-Print Network [OSTI]

    Shulman, Michael

    2015-01-01T23:59:59.000Z

    The American Physical Society (APS) March Meeting of condensed matter physics has grown to nearly 10,000 participants, comprises 23 individual APS groups, and even warrants its own hashtag (#apsmarch). Here we analyze the text and data from March Meeting abstracts of the past nine years and discuss trends in condensed matter physics over this time period. We find that in comparison to atomic, molecular, and optical physics, condensed matter changes rapidly, and that condensed matter appears to be moving increasingly toward subject matter that is traditionally in materials science and engineering.

  8. Incompressibility of strange matter

    E-Print Network [OSTI]

    Monika Sinha; Manjari Bagchi; Jishnu Dey; Mira Dey; Subharthi Ray; Siddhartha Bhowmick

    2004-04-01T23:59:59.000Z

    Strange stars calculated from a realistic equation of state (EOS), that incorporate chiral symmetry restoration as well as deconfinement at high density show compact objects in the mass radius curve. We compare our calculations of incompressibility for this EOS with that of nuclear matter. One of the nuclear matter EOS has a continuous transition to ud-matter at about five times normal density. Another nuclear matter EOS incorporates density dependent coupling constants. From a look at the consequent velocity of sound, it is found that the transition to ud-matter seems necessary.

  9. On the fate of vacuum bubbles on matter backgrounds

    E-Print Network [OSTI]

    Aleksandar Rakic; Dennis Simon; Julian Adamek; Jens C. Niemeyer

    2009-11-19T23:59:59.000Z

    In this letter we discuss cosmological first order phase transitions with de Sitter bubbles nucleating on (inhomogeneous) matter backgrounds. The de Sitter bubble can be a toy model for an inflationary phase of universes like our own. Using the thin wall approximation and the Israel junction method we trace the classical evolution of the formed bubbles within a compound model. We first address homogeneous ambient space (FRW model) and already find that bubbles nucleated in a dust dominated background cannot expand. For an inhomogeneous dust background (LTB model) we describe cases with at least initially expanding bubbles. Yet, an ensuing passage of the bubble wall through ambient curvature inhomogeneities remains unnoticed for observers inside the bubble. Notable effects also for interior observers are found in the case of a rapid background phase transition in a FRW model.

  10. On the fate of vacuum bubbles on matter backgrounds

    E-Print Network [OSTI]

    Rakic, Aleksandar; Adamek, Julian; Niemeyer, Jens C

    2009-01-01T23:59:59.000Z

    In this letter we discuss cosmological first order phase transitions with de Sitter bubbles nucleating on (inhomogeneous) matter backgrounds. The de Sitter bubble can be a toy model for an inflationary phase of universes like our own. Using the thin wall approximation and the Israel junction method we trace the classical evolution of the formed bubbles within a compound model. We first address homogeneous ambient space (FRW model) and already find that bubbles nucleated in a dust dominated background cannot expand. For an inhomogeneous dust background (LTB model) we describe cases with at least initially expanding bubbles. Yet, an ensuing passage of the bubble wall through ambient curvature inhomogeneities remains unnoticed for observers inside the bubble. Notable effects also for interior observers are found in the case of a rapid background phase transition in a FRW model.

  11. Smokes from the burning of aviation fuel and their self-lofting by solar heating

    SciTech Connect (OSTI)

    Radke, L.F.; Lyons, J.H.; Hobbs, P.V. (Univ. of Washington, Seattle (USA)); Weiss, R.E. (Radiance Research, Inc., Seattle, WA (USA))

    1990-08-20T23:59:59.000Z

    The emission factors and optical properties of smokes produced by the burning of aviation fuel were determined from airborne measurements. These rather large fires (30 m in diameter and containing as much as 4.5 {times} 10{sup 4} liters of fuel) produced dark columns of smoke. On several occasions the smoke was observed to continue to rise slowly after its initial stabilization at a temperature inversion. This rise was evidently due to the absorption of solar radiation by the smoke.

  12. Big Questions: Dark Matter

    ScienceCinema (OSTI)

    Lincoln, Don

    2014-08-07T23:59:59.000Z

    Carl Sagan's oft-quoted statement that there are "billions and billions" of stars in the cosmos gives an idea of just how much "stuff" is in the universe. However scientists now think that in addition to the type of matter with which we are familiar, there is another kind of matter out there. This new kind of matter is called "dark matter" and there seems to be five times as much as ordinary matter. Dark matter interacts only with gravity, thus light simply zips right by it. Scientists are searching through their data, trying to prove that the dark matter idea is real. Fermilab's Dr. Don Lincoln tells us why we think this seemingly-crazy idea might not be so crazy after all.

  13. Contribution of vehicle emissions to ambient carbonaceous particulate matter: A review and synthesis of the available data in the South Coast Air Basin. Final report

    SciTech Connect (OSTI)

    Cass, G.R.

    1997-02-01T23:59:59.000Z

    Table of Contents: Executive Summary; Introduction; Ambient Carbonaceous Particulate Matter in the South Coast Air Basin; Measurements of Emissions from In-Use Motor Vehicles in the South Coast Air Basin; Integration of Emissions Measurements into Comprehensive Emissions Inventories; Relating Emissions fom Motor Vehicles to Particulate Air Quality; Synthesis: The Combined Effect of All Vehicle-Related Source Contributions Acting Together; Trends in More Recent Years; Opportunities for Further Research; References; Appendix A: Detailed Mass Emissions Rates for Organic Compounds from Motor Vehicle Exhaust; and Appendix B: Organic Compounds Emitted from Tire Dust, Paved Road Dust, and Brake Lining Wear Dust.

  14. Dust and Molecules at High Redshift

    E-Print Network [OSTI]

    F. Combes

    1998-12-23T23:59:59.000Z

    In the last years, progress has been very rapid in the domain of molecules at high redshift, and we know in better detail now the molecular and dust content in several systems beyond z=1 and up to z = 5. The first discovery in 1992 by Brown and van den Bout of CO lines at z=2.28 in a gravitationally lensed starburst galaxy, strongly stimulated searches of other systems, but these were harder than foreseen, and less than 10 other systems have been discovered in CO emission. Redshifts range between 2 and 5, the largest being BR1202-0725 at z=4.69. Most of these systems, if not all, are gravitationally amplified objects. Some have been discovered first through their dust emission, relatively easy to detect because of the negative K-correction effect. The detection of all these systems could give an answer about the debated question of the star-formation rate as a function of redshift. The maximum of star-formation rate, found around z=2 from optical studies, could shift to higher z if the most remote objects are hidden by dust. Absorption in front of quasars can also probe cold gas at high redshift, taking advantage of very high spatial (milli arcsec) and spectral (30m/s) resolutions. From the diffuse components, one can measure the cosmic black body temperature as a function of redshift. All these preliminary studies will be carried out at large scales with future millimeter instruments, and some perspectives are given.

  15. Measurement and modeling of the Saharan dust radiative impact: Overview of the Saharan Dust Experiment (SHADE)

    E-Print Network [OSTI]

    Highwood, Ellie

    on Climate Change (IPCC), 2001]. Among the different aerosol types, mineral dust is one of the major to their scattering and absorbing properties that affect the solar radiation, they also perturb the terrestrial but they still represent one of the largest uncer- tainties in climate change studies [Intergovernmental Panel

  16. Effects of dust size distribution on dust negative ion acoustic solitary waves in a magnetized dusty plasma

    SciTech Connect (OSTI)

    Ma, Yi-Rong; Qi, Xin; Sun, Jian-An; Duan, Wen-Shan [Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China and College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 (China)] [Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China and College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 (China); Yang, Lei [Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China and College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 (China) [Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China and College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 (China); Department of Physics, Lanzhou University, Lanzhou 730000 (China)

    2013-08-15T23:59:59.000Z

    Dust negative ion acoustic solitary waves in a magnetized multi-ion dusty plasma containing hot isothermal electron, ions (light positive ions and heavy negative ions) and extremely massive charge fluctuating dust grains are investigated by employing the reductive perturbation method. How the dust size distribution affect the height and the thickness of the nonlinear solitary wave are given. It is noted that the characteristic of the solitary waves are different with the different dust size distribution. The magnitude of the external magnetic field also affects the solitary wave form.

  17. ARM - PI Product - Niamey Dust Observations

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadap Documentation TDMADAP : XDCnarrowbandheatProductsISDAC MicrophysicsProductsNauruDust

  18. DOE/El%0297 Dust. Category

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power Administration wouldDECOMPOSITION OF CALCIUMCOSTDOENuclear1382 THE HUMANlviA,'{ ' -297 Dust.

  19. AMERICAN JOURNAL OF INDUSTRIAL MEDICINE 49:709718 (2006) Smoking Imputation and Lung Cancer in

    E-Print Network [OSTI]

    Reid, Nancy

    2006-01-01T23:59:59.000Z

    AMERICAN JOURNAL OF INDUSTRIAL MEDICINE 49:709­718 (2006) Smoking Imputation and Lung Cancer exhaust exposure and lung cancer mortality in a large retrospective cohort study of US railroad workers­1996. Mortality analyses incorporated the effect of smoking on lung cancer risk. Results The smoking adjusted

  20. Radiative Effects of Dust Aerosols, Natural Cirrus Clouds and Contrails: Broadband Optical Properties and Sensitivity Studies

    E-Print Network [OSTI]

    Yi, Bingqi

    2013-07-09T23:59:59.000Z

    This dissertation aims to study the broadband optical properties and radiative effects of dust aerosols and ice clouds. It covers three main topics: the uncertainty of dust optical properties and radiative effects from the dust particle shape...

  1. Radiative Effects of Dust Aerosols, Natural Cirrus Clouds and Contrails: Broadband Optical Properties and Sensitivity Studies 

    E-Print Network [OSTI]

    Yi, Bingqi

    2013-07-09T23:59:59.000Z

    This dissertation aims to study the broadband optical properties and radiative effects of dust aerosols and ice clouds. It covers three main topics: the uncertainty of dust optical properties and radiative effects from the dust particle shape...

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

    E-Print Network [OSTI]

    Pargmann, Amber Rae

    2001-01-01T23:59:59.000Z

    , 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...

  3. The large scale dust lanes of the Galactic bar

    E-Print Network [OSTI]

    D. J. Marshall; R. Fux; A. C. Robin; C. Reyle

    2007-11-15T23:59:59.000Z

    (abridged) By comparing the distribution of dust and gas in the central regions of the Galaxy, we aim to obtain new insights into the properties of the offset dust lanes leading the bar's major axis in the Milky Way. On the one hand, the molecular emission of the dust lanes is extracted from the observed CO l-b-V distribution according to the interpretation of a dynamical model. On the other hand, a three dimensional extinction map of the Galactic central region constructed from near-infrared observations is used as a tracer of the dust itself and clearly reveals dust lanes in its face-on projection. Comparison of the position of both independent detections of the dust lanes is performed in the (l, b) plane. These two completely independent methods are used to provide a coherent picture of the dust lanes in the Milky Way bar. In both the gas and dust distributions, the dust lanes are found to be out of the Galactic plane, appearing at negative latitudes for l > 0 deg and at positive latitudes for l reformation downstream. Due to the decrease in velocity caused by the shock, this occurs at lower z. The second assumes that the gas and dust remain on a common tilted plane, but that the molecular gas decouples from the Milky Way's magnetic field, itself strong enough to resist the shear of the bar's shock. The diffuse gas and dust remain coupled to the field and are carried further downstream. This second scenario has recently been suggested in order to explain observations of the barred galaxy NGC 1097.

  4. RESEARCH Open Access Transient receptor potential genes, smoking,

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    RESEARCH Open Access Transient receptor potential genes, smoking, occupational exposures and cough chemicals and may play an important role in the pathogenesis of cough. The aim was to study the influence of single nucleotide polymorphisms (SNPs) in TRP genes and irritant exposures on cough. Methods: Nocturnal

  5. lung cancer smoke-free 6 One man's

    E-Print Network [OSTI]

    Roy, Subrata

    Fighting lung cancer Living smoke-free 6 One man's mission85 #12;Cure is the newsletter for the University of Florida Shands Cancer Center, home to cancer care and research for the Southeast's most? For more information about care and services offered at the UF Shands Cancer Center, call 352

  6. ANALYSIS OF DUST DELIQUESCENCE FOR FEP SCREENING

    SciTech Connect (OSTI)

    C. Bryan

    2005-08-26T23:59:59.000Z

    The purpose of this report is to evaluate the potential for penetration of the Alloy 22 (UNS N06022) waste package outer barrier by localized corrosion due to the deliquescence of soluble constituents in dust present on waste package surfaces. The results support a recommendation to exclude deliquescence-induced localized corrosion (pitting or crevice corrosion) of the outer barrier from the total system performance assessment for the license application (TSPA-LA). Preparation of this report, and supporting laboratory studies and calculations, were performed as part of the planned effort in Work Package AEBM21, as implemented in ''Technical Work Plan for: Screening Evaluation for Dust Deliquescence and Localized Corrosion'' (BSC 2004 [DIRS 172804]), by Bechtel SAIC Company, LLC, and staff from three national laboratories: Sandia National Laboratories, Lawrence Livermore National Laboratory (LLNL), and Lawrence Berkeley National Laboratory (LBNL). The analysis and conclusions presented in this report are quality affecting, as determined in the controlling technical work plan. A summary of background information, based on work that was not performed under a quality assurance program, is provided as Appendix E. In this instance, the use of unqualified information is provided for transparency and corroboration only, and is clearly separated from uses of qualified information. Thus, the qualification status of this information does not affect the conclusions of this report. The acceptance criteria addressed in Sections 4.2 and 7.2 were changed from the technical work plan in response to review comments received during preparation of this report.

  7. Smoke inputs to climate models: optical properties and height distribution for nuclear winter studies

    SciTech Connect (OSTI)

    Penner, J.E.; Haselman, L.C. Jr.

    1985-04-01T23:59:59.000Z

    Smoke from fires produced in the aftermath of a major nuclear exchange has been predicted to cause large decreases in land surface temperatures. The extent of the decrease and even the sign of the temperature change depend on the optical characteristics of the smoke and how it is distributed with altitude. The height distribution of smoke over a fire is determined by the amount of buoyant energy produced by the fire and the amount of energy released by the latent heat of condensation of water vapor. The optical properties of the smoke depend on the size distribution of smoke particles which changes due to coagulation within the lofted plume. We present calculations demonstrating these processes and estimate their importance for the smoke source term input for climate models. For high initial smoke densities and for absorbing smoke ( m = 1.75 - 0.3i), coagulation of smoke particles within the smoke plume is predicted to first increase, then decrease, the size-integrated extinction cross section. However, at the smoke densities predicted in our model (assuming a 3% emission rate for smoke) and for our assumed initial size distribution, the attachment rates for brownian and turbulent collision processes are not fast enough to alter the smoke size distribution enough to significantly change the integrated extinction cross section. Early-time coagulation is, however, fast enough to allow further coagulation, on longer time scales, to act to decrease the extinction cross section. On these longer time scales appropriate to climate models, coagulation can decrease the extinction cross section by almost a factor of two before the smoke becomes well mixed around the globe. This process has been neglected in past climate effect evaluations, but could have a significant effect, since the extinction cross section enters as an exponential factor in calculating the light attenuation due to smoke. 10 refs., 20 figs.

  8. The gas temperature in circumstellar disks: effects of dust settling

    E-Print Network [OSTI]

    Zadelhoff, Gerd-Jan van

    Example of the cooling and heating terms for a model with dust depletion in the surface Work in progress systems. One of the central questions concerning these disks are their density and temperature temperature is calculated solving the heating-cooling balance. Dust temperature Density distribution [cm ] -3

  9. Controlling dust when cutting fibre-cement board

    E-Print Network [OSTI]

    Knowles, David William

    Controlling dust when cutting fibre-cement board Page 1 of 2 Cutting fibre-cement board (e are not typically used when cutting and shaping fibre-cement board. To protect yourself you should: Use one of the methods described above for cutting fibre-· cement board Inspect the dust control equipment before you

  10. Dynamics of Finite Dust Clouds in a Magnetized Anodic Plasma

    SciTech Connect (OSTI)

    Piel, A.; Pilch, I.; Trottenberg, T. [Institute for Experimental and Applied Physics, Christian-Albrechts University, D-24098 Kiel (Germany); Koepke, M. E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26505-6315 (United States)

    2008-09-07T23:59:59.000Z

    The response to an external modulation voltage of small dust clouds confined in an anodic plasma is studied. Dust density waves are excited when the cloud is larger than a wavelength, whereas a sloshing and stretching motion is found for smaller clouds. The wave dispersion shows similarities with waveguide modes.

  11. Learn about the dangers of breathing silica dust

    E-Print Network [OSTI]

    Knowles, David William

    dust builds up in your lungs, you are at risk of developing a serious and irreversible lung disease silica dust. The fine particles are deposited in the lungs, causing thickening and scarring of the lung tissue. Crystalline silica exposure has also been linked to lung cancer. A worker may develop any

  12. An Alternate Approach to Determine the Explosibility of Dusts

    E-Print Network [OSTI]

    Ganesan, Balaji

    2013-12-04T23:59:59.000Z

    protocol that more accurately characterizes the explosibility of dusts. The CAAQES protocol for determining MEC is to test a wide range of concentrations of a dust in a 28.3-L (1 ft^(3)) Plexiglas chamber with a diaphragm and a stationary ignition source...

  13. HIGH FIDELITY STUDIES OF INTERSTELLAR DUST ANALOGUE IMPACTS IN STARDUST

    E-Print Network [OSTI]

    HIGH FIDELITY STUDIES OF INTERSTELLAR DUST ANALOGUE IMPACTS IN STARDUST AEROGEL AND FOILS F://www.ssl.berkeley.edu/~westphal/ISPE/. In 2000 and 2002 the Stardust Mission exposed aerogel collector panels for a total of about 200 days/s] interstellar dust (ISD) analogues onto Stardust aerogel and foil flight spares. Particle impact speeds up to 50

  14. Dust en-route to Jupiter and the Galilean satellites

    E-Print Network [OSTI]

    Harald Krueger; Eberhard Gruen

    2002-05-28T23:59:59.000Z

    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.

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

    E-Print Network [OSTI]

    Sullivan, Ryan Christopher

    2008-01-01T23:59:59.000Z

    of completely processed calcium carbonate dust particles,of completely processed calcium carbonate dust particles,and Solubility of Calcium-Carbonate Monohydrate, Colloid

  16. Sheath formation under collisional conditions in presence of dust

    SciTech Connect (OSTI)

    Moulick, R., E-mail: rakesh.moulick@gmail.com; Goswami, K. S. [Centre of Plasma Physics-Institute for Plasma Research, Sonapur-782402, Guwahati (India)

    2014-08-15T23:59:59.000Z

    Sheath formation is studied for collisional plasma in presence of dust. In common laboratory plasma, the dust acquires negative charges because of high thermal velocity of the electrons. The usual dust charging theory dealing with the issue is that of the Orbit Motion Limited theory. However, the theory does not find its application when the ion neutral collisions are significantly present. An alternate theory exists in literature for collisional dust charging. Collision is modeled by constant mean free path model. The sheath is considered jointly with the bulk of the plasma and a smooth transition of the plasma profiles from the bulk to the sheath is obtained. The various plasma profiles such as the electrostatic force on the grain, the ion drag force along with the dust density, and velocity are shown to vary spatially with increasing ion neutral collision.

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

    SciTech Connect (OSTI)

    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

    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.

  18. Existence domains of dust-acoustic solitons and supersolitons

    SciTech Connect (OSTI)

    Maharaj, S. K. [South African National Space Agency (SANSA) Space Science, PO Box 32, Hermanus 7200 (South Africa)] [South African National Space Agency (SANSA) Space Science, PO Box 32, Hermanus 7200 (South Africa); Bharuthram, R. [University of the Western Cape, Robert Sobukwe Road, Bellville 7535 (South Africa)] [University of the Western Cape, Robert Sobukwe Road, Bellville 7535 (South Africa); Singh, S. V.; Lakhina, G. S. [Indian Institute of Geomagnetism, New Panvel, Navi Mumbai 410218 (India)] [Indian Institute of Geomagnetism, New Panvel, Navi Mumbai 410218 (India)

    2013-08-15T23:59:59.000Z

    Using the Sagdeev potential method, the existence of large amplitude dust-acoustic solitons and supersolitons is investigated in a plasma comprising cold negative dust, adiabatic positive dust, Boltzmann electrons, and non-thermal ions. This model supports the existence of positive potential supersolitons in a certain region in parameter space in addition to regular solitons having negative and positive potentials. The lower Mach number limit for supersolitons coincides with the occurrence of double layers whereas the upper limit is imposed by the constraint that the adiabatic positive dust number density must remain real valued. The upper Mach number limits for negative potential (positive potential) solitons coincide with limiting values of the negative (positive) potential for which the negative (positive) dust number density is real valued. Alternatively, the existence of positive potential solitons can terminate when positive potential double layers occur.

  19. Processing electric arc furnace dust into saleable chemical products

    SciTech Connect (OSTI)

    NONE

    1998-04-01T23:59:59.000Z

    The modern steel industry uses electric arc furnace (EAF) technology to manufacture steel. A major drawback of this technology is the production of EAF dust, which is listed by the U.S. Environmental Protection Agency as a hazardous waste under the Resource Conservation and Recovery Act. The annual disposal of approximately 0.65 million tons of EAF dust in the United States and Canada is an expensive, unresolved problem for the steel industry. EAF dust byproducts are generated during the manufacturing process by a variety of mechanisms. The dust consists of various metals (e.g., zinc, lead, cadmium) that occur as vapors at 1,600{degrees}C (EAF hearth temperature); these vapors are condensed and collected in a baghouse. The production of one ton of steel will generate approximately 25 pounds of EAF dust as a byproduct, which is currently disposed of in landfills.

  20. Matter: Space without Time

    E-Print Network [OSTI]

    Yousef Ghazi-Tabatabai

    2012-11-19T23:59:59.000Z

    While Quantum Gravity remains elusive and Quantum Field Theory retains the interpretational difficulties of Quantum Mechanics, we have introduced an alternate approach to the unification of particles, fields, space and time, suggesting that the concept of matter as space without time provides a framework which unifies matter with spacetime and in which we anticipate the development of complete theories (ideally a single unified theory) describing observed 'particles, charges, fields and forces' solely with the geometry of our matter-space-time universe.

  1. Energy Matters Mailbag

    Broader source: Energy.gov [DOE]

    This edition of the mailbag tackles follow-up questions from our Energy Matters discussion on breaking our reliance on foreign oil.

  2. Effects of interactive transport and scavenging of smoke on the calculated temperature change resulting from large amounts of smoke

    SciTech Connect (OSTI)

    MacCracken, M.C.; Walton, J.J.

    1984-12-01T23:59:59.000Z

    Several theoretical studies with numerical models have shown that substantial land-surface cooling can occur if very large amounts (approx. 100 x 10/sup 12/ = 100 Tg) of highly absorbing sooty-particles are injected high into the troposphere and spread instantaneously around the hemisphere (Turco et al., 1983; Covey et al. 1984; MacCracken, 1983). A preliminary step beyond these initial calculations has been made by interactively coupling the two-layer, three-dimensional Oregon State University general circulation model (GCM) to the three-dimensional GRANTOUR trace species model developed at the Lawrence Livermore National Laboratory. The GCM simulation includes treatment of tropospheric dynamics and thermodynamics and the effect of soot on solar radiation. The GRANTOUR simulation includes treatment of particle transport and scavenging by precipitation, although no satisfactory verification of the scavenging algorithm has yet been possible. We have considered the climatic effects of 150 Tg (i.e., the 100 Mt urban war scenario from Turco et al., 1983) and of 15 Tg of smoke from urban fires over North America and Eurasia. Starting with a perpetual July atmospheric situation, calculation of the climatic effects as 150 Tg of smoke are spread slowly by the winds, rather than instantaneously dispersed as in previous calculations, leads to some regions of greater cooling under the denser parts of the smoke plumes and some regions of less severe cooling where smoke arrival is delayed. As for the previous calculations, mid-latitude decreases of land surface air temperature for the 150 Tg injection are greater than 15/sup 0/C after a few weeks. For a 15 Tg injection, however, cooling of more than several degrees centigrade only occurs in limited regions under the dense smoke plumes present in the first few weeks after the injection. 10 references, 9 figures.

  3. Ordered dust structures in a glow discharge

    SciTech Connect (OSTI)

    Karasev, V. Yu., E-mail: plasmadust@yandex.ru; Ivanov, A. Yu.; Dzlieva, E. S.; Eikhval'd, A. I. [St. Petersburg State University, Institute of Physics (Russian Federation)

    2008-02-15T23:59:59.000Z

    Highly ordered three-dimensional dust structures are created in a striated glow discharge, and their horizontal cross-sectional images are analyzed. Calculated correlation functions, local correlation parameters, and corresponding approximations are used to classify the state of a structure according to the Kosterlitz-Thouless-Halperin-Nelson-Young (KTHNY) two-dimensional melting theory and a phenomenological approach. An orientational map based on an orientational parameter is proposed to expose domains in a cross section of a structure. It is shown that a plasma crystal is a polycrystal consisting of hexagonal domains (crystallites). Thermophoretic forces are used to create corners of various angles in the perimeter of the structure. Transition between hexagonal and square cell shapes is observed.

  4. Temperature fluctuations of interstellar dust grains

    E-Print Network [OSTI]

    Kobi Horn; Hagai B. Perets; Ofer Biham

    2007-09-20T23:59:59.000Z

    The temperatures of interstellar dust grains are analyzed using stochastic simulations, taking into account the grain composition and size and the discreteness of the photon flux. [...] The distribution of grain temperatures is calculated for a broad range of grain sizes and for different intensities of the interstellar radiation field, relevant to diffuse clouds and to PDRs. The dependence of the average grain temperature on its size is shown for different irradiation intensities. It is found that the average temperatures of grains with radii smaller than about 0.02 $\\mu$m are reduced due to the fluctuations. The average temperatures of grains of radii larger than about 0.35 $\\mu$m are also slightly reduced due to their more efficient emission of infrared radiation, particularly when exposed to high irradiation intensities. The average temperatures of silicate and carbonaceous grains are found to depend on the radiation field intensity X_MMP according to ~X_MMP^gamma, where the exponent gamma depends on the grain size and composition. This fitting formula is expected to be useful in simulations of interstellar processes, and can replace commonly used approximations which do not account for the grain temperature fluctuations and for the detailed properties of interstellar dust particles. The implications of the results on molecular hydrogen formation are also discussed. It is concluded that grain-temperature fluctuations tend to reduce the formation rate of molecular hydrogen, and cannot account for the observations of H_2 in photon dominated regions, even in the presence of chemisorption sites.

  5. Dipolar Dark Matter

    E-Print Network [OSTI]

    Blanchet, Luc

    2015-01-01T23:59:59.000Z

    Massive gravity theories have been developed as viable IR modifications of gravity motivated by dark energy and the problem of the cosmological constant. On the other hand, modified gravity and modified dark matter theories were developed with the aim of solving the problems of standard cold dark matter at galactic scales. Here we propose to adapt the framework of ghost-free massive bigravity theories to reformulate the problem of dark matter at galactic scales. We investigate a promising alternative to dark matter called dipolar dark matter (DDM) in which two different species of dark matter are separately coupled to the two metrics of bigravity and are linked together by an internal vector field. We show that this model successfully reproduces the phenomenology of dark matter at galactic scales (i.e. MOND) as a result of a mechanism of gravitational polarisation. The model is safe in the gravitational sector, but because the two types of dark matter interact through the vector field, a ghostly degree of fre...

  6. Dark matter and cosmology

    SciTech Connect (OSTI)

    Schramm, D.N.

    1992-03-01T23:59:59.000Z

    The cosmological dark matter problem is reviewed. The Big Bang Nucleosynthesis constraints on the baryon density are compared with the densities implied by visible matter, dark halos, dynamics of clusters, gravitational lenses, large-scale velocity flows, and the {Omega} = 1 flatness/inflation argument. It is shown that (1) the majority of baryons are dark; and (2) non-baryonic dark matter is probably required on large scales. It is also noted that halo dark matter could be either baryonic or non-baryonic. Descrimination between ``cold`` and ``hot`` non-baryonic candidates is shown to depend on the assumed ``seeds`` that stimulate structure formation. Gaussian density fluctuations, such as those induced by quantum fluctuations, favor cold dark matter, whereas topological defects such as strings, textures or domain walls may work equally or better with hot dark matter. A possible connection between cold dark matter, globular cluster ages and the Hubble constant is mentioned. Recent large-scale structure measurements, coupled with microwave anisotropy limits, are shown to raise some questions for the previously favored density fluctuation picture. Accelerator and underground limits on dark matter candidates are also reviewed.

  7. Dark matter and cosmology

    SciTech Connect (OSTI)

    Schramm, D.N.

    1992-03-01T23:59:59.000Z

    The cosmological dark matter problem is reviewed. The Big Bang Nucleosynthesis constraints on the baryon density are compared with the densities implied by visible matter, dark halos, dynamics of clusters, gravitational lenses, large-scale velocity flows, and the {Omega} = 1 flatness/inflation argument. It is shown that (1) the majority of baryons are dark; and (2) non-baryonic dark matter is probably required on large scales. It is also noted that halo dark matter could be either baryonic or non-baryonic. Descrimination between cold'' and hot'' non-baryonic candidates is shown to depend on the assumed seeds'' that stimulate structure formation. Gaussian density fluctuations, such as those induced by quantum fluctuations, favor cold dark matter, whereas topological defects such as strings, textures or domain walls may work equally or better with hot dark matter. A possible connection between cold dark matter, globular cluster ages and the Hubble constant is mentioned. Recent large-scale structure measurements, coupled with microwave anisotropy limits, are shown to raise some questions for the previously favored density fluctuation picture. Accelerator and underground limits on dark matter candidates are also reviewed.

  8. A New Dust Budget In The Large Magellanic Cloud

    E-Print Network [OSTI]

    Zhu, Chunhua; Wang, Zhaojun

    2015-01-01T23:59:59.000Z

    The origin of dust in a galaxy is poorly understood. Recently, the surveys of the Large Magellanic Cloud (LMC) provide astrophysical laboratories for the dust studies. By a method of population synthesis, we investigate the contributions of dust produced by asymptotic giant branch (AGB) stars, common envelope (CE) ejecta and type II supernovae (SNe II) to the total dust budget in the LMC. Based on our models, the dust production rates (DPRs) of AGB stars in the LMC are between about $2.5\\times10^{-5}$ and $4.0\\times10^{-6}M_\\odot{\\rm yr^{-1}}$. The uncertainty mainly results from different models for the dust yields of AGB stars. The DPRs of CE ejecta are about $6.3\\times10^{-6}$(The initial binary fraction is 50\\%). These results are within the large scatter of several observational estimates. AGB stars mainly produce carbon grains, which is consistent with the observations. Most of dust grains manufactured by CE ejecta are silicate and iron grains. The contributions of SNe II are very uncertain. Compared wi...

  9. A new method to generate dust with astrophysical properties

    SciTech Connect (OSTI)

    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

    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.

  10. Controlling Silver Dust and Fumes at Mine Refinery

    E-Print Network [OSTI]

    R. A. Haney; M. P. Valoski

    ABSTRACT: As part of the refining of gold and silver molten metal, silver dust and fumes are released into the atmosphere. The Mine Safety and Health Administration (MSHA) enforces an 8-hour, equivalent Time Weighted Average concentration limit for silver dust and fumes of 10 µg/m 3. MSHA initiated a program to assess the controls that were being used to control silver dust and fume exposure. Refineries were visited at six mines. The layout of each refinery and the controls used varied at each refinery. At each operation, personal and area silver fume and dust samples were collected to assess worker exposures and to determine sources of fume. Primary source of silver dust and fume exposure was the pouring of molten metal from the furnace. Secondary sources of exposure included: precipitate mixing, bar cooling, and housekeeping. Guidelines were developed addressing housekeeping, exhaust ventilation, general ventilation, administrative controls, and system monitoring. In most cases, housekeeping and general ventilation were adequate; however, the exhaust ventilation systems needed to be improved. 1 INRODUCTION Silver dust and fumes become airborne during the refining step of producing gold and silver. The dust

  11. Can Composite Fluffy Dust Particles Solve the Interstellar Carbon Crisis?

    E-Print Network [OSTI]

    E. Dwek

    1997-01-16T23:59:59.000Z

    Interstellar dust models are facing a "carbon crisis", so called because recent observations suggest that the abundance of carbon available for dust in the interstellar medium is less than half of the amount required to be tied up in graphite grains in order to explain the interstellar extinction curve. This paper presents an detailed assessment of a newly-proposed dust model (Mathis 1996), in which the majority of the interstellar carbon is contained in composite and fluffy dust (CFD) grains. Per unit mass, these grains produce more UV extinction, and can therefore account for the interstellar extinction curve with about half the carbon required in traditional dust models. The results of our analysis show that the CFD model falls short in solving the carbon crisis, in providing a fit to the UV-optical interstellar extinction curve. It also predicts a far-infrared emissivity in excess of that observed with the COBE/DIRBE and FIRAS instruments from the diffuse interstellar medium. The failure of the new model highlights the interrelationships between the various dust properties and their observational consequences, and the need to satisfy them all simultaneously in any comprehensive interstellar dust model. In light of these problems, the paper examines other possible solutions to the carbon crisis.

  12. The gravitational redshift of photons traversing a collapsing dust cloud and observable consequences

    E-Print Network [OSTI]

    Néstor Ortiz; Olivier Sarbach

    2014-11-24T23:59:59.000Z

    We analyze the frequency shift of photons propagating on an asymptotically flat spacetime describing a collapsing, spherical dust cloud. We focus on the case where the interaction of the photons with the matter can be neglected. Under fairly general assumptions on the initial data characterizing the collapse, we show that photons with zero angular momentum which travel from past to future null infinity, crossing the collapsing cloud through its center, are always redshifted with respect to stationary observers. We compute this redshift as a function of proper time of a distant stationary observer and discuss its dependency on the mass distribution of the cloud. Possible implications of this redshift effect for weak cosmic censorship and light propagation in cosmological spacetimes are also briefly discussed.

  13. Spatiotemporal evolution of dielectric driven cogenerated dust density waves

    SciTech Connect (OSTI)

    Sarkar, Sanjib; Bose, M. [Department of Physics, Jadavpur University, Kolkata 700032 (India)] [Department of Physics, Jadavpur University, Kolkata 700032 (India); Mukherjee, S. [FCIPT, Institute for Plasma Research, Gandhinagar 382428 (India)] [FCIPT, Institute for Plasma Research, Gandhinagar 382428 (India); Pramanik, J. [Kharagpur College, Kharagpur 721305, West Bengal (India)] [Kharagpur College, Kharagpur 721305, West Bengal (India)

    2013-06-15T23:59:59.000Z

    An experimental observation of spatiotemporal evolution of dust density waves (DDWs) in cogenerated dusty plasma in the presence of modified field induced by glass plate is reported. Various DDWs, such as vertical, oblique, and stationary, were detected simultaneously for the first time. Evolution of spatiotemporal complexity like bifurcation in propagating wavefronts is also observed. As dust concentration reaches extremely high value, the DDW collapses. Also, the oblique and nonpropagating mode vanishes when we increase the number of glass plates, while dust particles were trapped above each glass plates showing only vertical DDWs.

  14. Reducing dust emissions at OAO Alchevskkoks coke battery 10A

    SciTech Connect (OSTI)

    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

    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.

  15. Generalizations of the Störmer Problem for Dust Grain Orbits

    E-Print Network [OSTI]

    H. R. Dullin; M. Horányi; J. E. Howard

    2001-04-24T23:59:59.000Z

    We consider the generalized St\\"ormer Problem that includes the electromagnetic and gravitational forces on a charged dust grain near a planet. For dust grains a typical charge to mass ratio is such that neither force can be neglected. Including the gravitational force gives rise to stable circular orbits that encircle that plane entirely above/below the equatorial plane. The effects of the different forces are discussed in detail. A modified 3rd Kepler's law is found and analyzed for dust grains.

  16. On interaction of large dust grains with fusion plasma

    SciTech Connect (OSTI)

    Krasheninnikov, S. I.; Smirnov, R. D. [University of California at San Diego, La Jolla, California 92093 (United States)

    2009-11-15T23:59:59.000Z

    So far the models used to study dust grain-plasma interactions in fusion plasmas neglect the effects of dust material vapor, which is always present around dust in rather hot and dense edge plasma environment in fusion devices. However, when the vapor density and/or the amount of ionized vapor atoms become large enough, they can alter the grain-plasma interactions. Somewhat similar processes occur during pellet injection in fusion plasma. In this brief communication the applicability limits of the models ignoring vapor effects in grain-plasma interactions are obtained.

  17. Screening of the Reissner-Nordström charge by a thin-shell of dust matter

    E-Print Network [OSTI]

    S. Habib Mazharimousavi; M. Halilsoy

    2015-03-17T23:59:59.000Z

    A concentric thin-shell encircling a Reissner-Nordstr\\"om (RN) black hole screens the internal charge completely to match with an external Schwarzschild (S) black hole. The negative mass thin-shell is shown to be stable against radial perturbations. It is shown further that by reversing the roles of inside (RN) and outside (S) geometries the mass of the appropriate shell becomes positive.

  18. Screening of the Reissner-Nordstr\\"om charge by a thin-shell of dust matter

    E-Print Network [OSTI]

    Mazharimousavi, S Habib

    2015-01-01T23:59:59.000Z

    A concentric thin-shell encircling a Reissner-Nordstr\\"om (RN) black hole screens the internal charge completely to match with an external Schwarzschild (S) black hole. The negative mass thin-shell is shown to be stable against radial perturbations. It is shown further that by reversing the roles of inside (RN) and outside (S) geometries the mass of the appropriate shell becomes positive.

  19. Physical and chemical characterization of smoke from several fuels

    SciTech Connect (OSTI)

    Novakov, T.

    1988-08-01T23:59:59.000Z

    This paper summarizes the experimental approaches used and the results obtained at Lawrence Berkeley Laboratory on physico-chemical properties of smokes from several fuels. These experiments were principally designed to contribute to the assessment of environmental consequences of a nuclear war (''nuclear winter''). We believe, however, that the results and the experimental methodology used are of interest to the broader fire research community. The smoke particle sampling and analysis methods were originally developed for studies of atmospheric aerosol particles. In these atmospheric applications, it is important to acquire at a minimum information about particle mass, particle size distribution and chemical composition of the particles as a function of particle size. Which specific chemical species and compounds are analyzed is determined by the objectives of the particular study. Depending on these objectives, specific gaseous compounds may be monitored, particularly those that serve as precursors for the formation of aerosols by various gas-to-particle conversion processes. 6 refs., 4 figs.

  20. Atmospheric effects of nuclar war aerosols in general circulation model simulations: Influence of smoke optical properties

    SciTech Connect (OSTI)

    Thompson, S.L.; Ramaswamy, V.; Covey, C.

    1987-09-20T23:59:59.000Z

    A global atmospheric general circulation model (GCM) is modified to include radiative transfer parameterizations for the absorption and scattering of solar radiation and the absorption of thermal infrared (IR) radiation by smoke aerosols. The solar scattering modifications include a parameterization for diagnosing smoke optical properties as a function of the time- and space-dependent smoke particle radii. The aerosol IR modifications allow for both the ''grey'' absorber approximation and a broadband approximation that resolves the aerosol absorption in four spectral intervals. We examine the sensitivity of some GCM-simulated atmospheric and climatic effects to the optical properties and radiative transfer parameterizations used in studies of massive injections of smoke. Specifically, we test the model response to solar scattering versus nonscattering smoke, variations in prescribed smoke single scattering albedo and IR specific absorption, and interactive versus fixed smoke optical properties. Hypothetical nuclear war created smoke scenarios assume the July injection of 60 or 180 Tg of smoke over portions of the mid-latitude land areas of the northern hemisphere. Atmospheric transport and scavenging of the smoke are included. Nonscattering smoke cases produce roughly 40 Wm/sup -2/ more Earth-atmosphere solar irradiance absorption over the northern hemisphere, when compared to scattering smoke cases having equivalent specific absorption efficiencies. Varying the elemental carbon content of smoke over a plausible range produces a 4/sup 0/--6 /sup 0/C change in average mid-latitude land surface temperature, and a variation of about 0.1 in zonally averaged planetary albedo in the northern hemisphere.

  1. Heterogeneous Chemistry of Individual Mineral Dust Particles from Different Dust Source Regions: The Importance of Particle Mineralogy

    SciTech Connect (OSTI)

    Krueger, Brenda J.; Grassian, Vicki H.; Cowin, James P.; Laskin, Alexander

    2004-11-01T23:59:59.000Z

    The heterogeneous chemistry of individual dust particles from four different dust source regions is investigated on a particle-by-particle basis using state-of-the-art scanning electron microscopy techniques including computer-controlled scanning electron microscopy/computer-controlled X-ray analysis (CCSEM/EDX). Morphology and compositional changes of individual particles as they react with nitric acid are observed. Clear differences in the reactivity of mineral dusts from these four different dust regions with nitric acid could be observed. Mineral dust from source regions containing high levels of calcium, such as those found in parts of China and Saudi Arabia, are found to react to the greatest extent. Calcium containing minerals, such as calcite (CaCO3) and dolomite (CaMg(CO3)2), react to form nitrate salt whereas other calcium containing minerals such as gypsum (CaSO4?2H2O) do not react. The importance of particle chemical composition and mineralogy in the heterogeneous chemistry of mineral dust aerosols is definitively borne out in this study of individual dust particles.

  2. Ice particle size matters | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Ice particle size matters Ice particle size matters Released: May 04, 2014 Fine-tuning cloud models for improved climate predictions The Science Arctic clouds are widespread and...

  3. Excitation of dust acoustic waves by an ion beam in a plasma cylinder with negatively charged dust grains

    SciTech Connect (OSTI)

    Sharma, Suresh C. [Department of Applied Physics, Delhi Technological University (DTU), Shahbad Daulatpur, Bawana Road, Delhi-42 (India); Kaur, Daljeet [Department of Physics, Guru Teg Bahadur Institute of Technology, Rajouri Garden, New Delhi (India); Gahlot, Ajay [Department of Physics, Maharaja Surajmal Institute of Technology, Janakpuri, New Delhi (India); Sharma, Jyotsna [Department of Physics, KIIT College of Engineering, Bhondsi Gurgaon 122102 (India)

    2014-10-15T23:59:59.000Z

    An ion beam propagating through a plasma cylinder having negatively charged dust grains drives a low frequency electrostatic dust acoustic wave (DAW) to instability via Cerenkov interaction. 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 to the one-third power of the beam density. The real part of the frequency of the unstable mode increases with the beam energy and scales to almost one-half power of the beam energy. The phase velocity, frequency, and wavelength results of the unstable mode are in compliance with the experimental observations.

  4. asthma dust mite: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    were compared to anti-cockroach, anti-mouse, and anti-dust mite IgE levels, wheeze, cough, eczema and asthma. Results: Correlations between CBMC and age 5 PBMC proliferation in...

  5. Dust-shell Universe in the modified gravity scenario

    E-Print Network [OSTI]

    Michael Maziashvili

    2005-04-15T23:59:59.000Z

    The dynamics of the dust-shell model of universe is exactly solved for the modified Schwarzschild solution. This solution is used to derive the cosmology corresponding to the modified gravity.

  6. Magnetorotational instability in plasmas with mobile dust grains

    SciTech Connect (OSTI)

    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

    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.

  7. Introduction Dust aerosols affect visibility, perturb the radiative energy balance

    E-Print Network [OSTI]

    Wang, Jun

    Sunphotometer and air temperature from ground observations. Model Flow Chart GOES-8 06/28/00 1145 UTC -90 -80Introduction Dust aerosols affect visibility, perturb the radiative energy balance of the earth

  8. The sudden appearance of dust in the early Universe

    E-Print Network [OSTI]

    Mattsson, Lars

    2015-01-01T23:59:59.000Z

    Observations suggest that high-redshift galaxies are either very dusty or essentially dust free. The evolution from one regime to the other must also be very fast, since evolved and dusty galaxies show up at redshifts corresponding to a Universe which is only about 500 Myr old. In the present paper models which predicts the existence of an apparent dichotomy between dusty and dust-free galaxies at high redshift are considered. Galaxies become dusty as soon as they reach an evolved state and the transition is very rapid. A special case suggests that while stellar dust production is overall relatively insignificant -- contrary to what has been argued recently -- it can at the same time be consistent with efficient dust production in supernovae in the local Universe. Special attention will be given to the recent discovery of a dusty normal galaxy (A1689-zD1) at a very high redshift z = 7.5 +/- 0.2.

  9. african dust measured: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    swath of the HiRISE instrument has three separate charge-coupled devices (CCDs) and color filters that observe the surface in rapid cadence. Active features, such as dust devils,...

  10. Dynamical modeling of the Deep Impact dust ejecta cloud

    E-Print Network [OSTI]

    Tanyu Bonev; Nancy Ageorges; Stefano Bagnulo; Luis Barrera; Hermann B{ö}hnhardt; Olivier Hainaut; Emmanuel Jehin; Hans-Ullrich K{ä}ufl; Florian Kerber; Gaspare LoCurto; Jean Manfroid; Olivier Marco; Eric Pantin; Emanuela Pompei; Ivo Saviane; Fernando Selman; Chris Sterken; Heike Rauer; Gian Paolo Tozzi; Michael Weiler

    2007-03-21T23:59:59.000Z

    The collision of Deep Impact with comet 9P/Tempel 1 generated a bright cloud of dust which dissipated during several days after the impact. The brightness variations of this cloud and the changes of its position and shape are governed by the physical properties of the dust grains. We use a Monte Carlo model to describe the evolution of the post-impact dust plume. The results of our dynamical simulations are compared to the data obtained with FORS2, the FOcal Reducer and low dispersion Spectrograph for the VLT of the European Southern Observatory (ESO), to derive the particle size distribution and the total amount of material contained in the dust ejecta cloud.

  11. Estimated Global Mortality Attributable to Smoke from Landscape Fires

    E-Print Network [OSTI]

    2012-01-01T23:59:59.000Z

    fine matter Phys shape peat Epidemiol cigarette episode.of carbon Forest, pollution peat approximately grasslandin Southeast Asia in and peat fires Estimated annual La Niña

  12. Dust size distribution and concentrations with cottonseed oil mills

    E-Print Network [OSTI]

    Wiederhold, Lee Roy

    1976-01-01T23:59:59.000Z

    DUST SIZE DISTRIBUTION AND CONCENTRATIONS WITHIN COTTONSEED OIL MILLS A Thesis by LEE ROY WIEDERHOLD, JR. / I Submitted to the Graduate College of Texas ARM University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE August 1976 Major Subject: Aqricultural Engineering DUST SIZE DISTRIBUTION AND CONCENTRATIONS WITHIN COTTONSEED OIL MILLS A Thesis by LEE ROY WIEDERHOLD, JR. Approved as to style and content by: Chairman of Committee ~Hd fdp t Member ber...

  13. The Connection Between Barstrength and Circumnuclear Dust Structure

    E-Print Network [OSTI]

    Molly Peeples; Paul Martini

    2006-08-03T23:59:59.000Z

    We present a comparison of barstrength Qb and circumnuclear dust morphology for 75 galaxies in order to investigate how bars affect the centers of galaxies. We trace the circumnuclear dust morphology and amount of dust structure with structure maps generated from visible-wavelength HST data, finding that tightly wound nuclear dust spirals are primarily found in weakly barred galaxies. While strongly barred galaxies sometimes exhibit grand design structure within the central 10 percent of D25, this structure rarely extends to within ~10 pc of the galaxy nucleus. In some galaxies, these spiral arms terminate at a circumnuclear starburst ring. Galaxies with circumnuclear rings are generally more strongly barred than galaxies lacking rings. Within these rings, the dust structure is fairly smooth and usually in the form of a loosely wound spiral. These data demonstrate that multiple nuclear morphologies are possible in the most strongly barred galaxies: chaotic central dust structure inconsistent with a coherent nuclear spiral, a grand design spiral that loses coherence before reaching the nucleus, or a grand design spiral that ends in a circumnuclear ring. These observations may indicate that not all strong bars are equally efficient at fueling material to the centers of their host galaxies. Finally, we investigate the longstanding hypothesis that SB(s) galaxies have weak bars and SB(r) galaxies have strong bars, finding the opposite to be the case: namely, SB(r) galaxies are less strongly barred and have less dust structure than SB(s) galaxies. In general, more strongly barred galaxies tend to have higher nuclear dust contrast.

  14. Sensitivity Study of the Effects of Mineral Dust Particle Nonsphericity and Thin Cirrus Clouds on MODIS Dust Optical Depth Retrievals and Direct Radiative Forcing Calculations

    E-Print Network [OSTI]

    Feng, Qian

    2011-10-21T23:59:59.000Z

    A special challenge posed by mineral dust aerosols is associated with their predominantly nonspherical particle shapes. In the present study, the scattering and radiative properties for nonspherical mineral dust aerosols at violet-to-blue (0.412, 0...

  15. Hot and dark matter

    E-Print Network [OSTI]

    D'Eramo, Francesco

    2012-01-01T23:59:59.000Z

    In this thesis, we build new Effective Field Theory tools to describe the propagation of energetic partons in hot and dense media, and we propose two new reactions for dark matter in the early universe. In the first part, ...

  16. Programmable matter by folding

    E-Print Network [OSTI]

    Wood, R. J.

    Programmable matter is a material whose properties can be programmed to achieve specific shapes or stiffnesses upon command. This concept requires constituent elements to interact and rearrange intelligently in order to ...

  17. The Heart of Matter

    E-Print Network [OSTI]

    Rohini M. Godbole

    2010-06-30T23:59:59.000Z

    In this article I trace the development of the human understanding of the "Heart of Matter" from early concepts of "elements" (or alternatively "Panchmahabhootas") to the current status of "quarks" and "leptons" as the fundamental constituents of matter, interacting together via exchange of the various force carrier particles called "gauge bosons" such as the photon, W/Z-boson etc. I would like to show how our understanding of the fundamental constituents of matter has gone hand in hand with our understanding of the fundamental forces in nature. I will also outline how the knowledge of particle physics at the "micro" scale of less than a Fermi(one millionth of a nanometer), enables us to offer explanations of Cosmological observations at the "macro" scale. Consequently these observations, may in turn, help us address some very fundamental questions of the Physics at the "Heart of the Matter".

  18. Matter & Energy Electronics

    E-Print Network [OSTI]

    Suslick, Kenneth S.

    See also: Matter & Energy Electronics· Detectors· Technology· Construction· Sports Science Electronic Tongue Tastes Wine Variety, Vintage (Aug. 12, 2008) -- You don't need a wine expert to Advance

  19. Gaseous dark matter detectors

    E-Print Network [OSTI]

    Martoff, C. J.

    Dark matter (DM) detectors with directional sensitivity have the potential of yielding an unambiguous positive observation of WIMPs as well as discriminating between galactic DM halo models. In this paper, we introduce the ...

  20. The dust mass in z > 6 normal star forming galaxies

    E-Print Network [OSTI]

    Mancini, Mattia; Graziani, Luca; Valiante, Rosa; Dayal, Pratika; Maio, Umberto; Ciardi, Benedetta; Hunt, Leslie K

    2015-01-01T23:59:59.000Z

    We interpret recent ALMA observations of z > 6 normal star forming galaxies by means of a semi-numerical method, which couples the output of a cosmological hydrodynamical simulation with a chemical evolution model which accounts for the contribution to dust enrichment from supernovae, asymptotic giant branch stars and grain growth in the interstellar medium. We find that while stellar sources dominate the dust mass of small galaxies, the higher level of metal enrichment experienced by galaxies with Mstar > 10^9 Msun allows efficient grain growth, which provides the dominant contribution to the dust mass. Even assuming maximally efficient supernova dust production, the observed dust mass of the z = 7.5 galaxy A1689-zD1 requires very efficient grain growth. This, in turn, implies that in this galaxy the average density of the cold and dense gas, where grain growth occurs, is comparable to that inferred from observations of QSO host galaxies at similar redshifts. Although plausible, the upper limits on the dust ...

  1. Evaluate fundamental approaches to longwall dust control. Phase III report

    SciTech Connect (OSTI)

    Babbitt, C.; Bartlett, P.; Kelly, J.; Ludlow, J.; Mangolds, A.; Rajan, S.; Ruggieri, S.; Varga, E.

    1984-03-31T23:59:59.000Z

    The overall objective of the contract is to evaluate the effectiveness of available dust control technology for double-drum shearer longwall sections in a coordinated, systematic program at a few longwall test sections and to make the results available to the entire coal mining industry. This program is investigating nine different dust control techniques. These nine subprograms encompass a broad range of dust control measures ranging from administrative controls to new hardware. They span not only presently employed methods but also those recently adopted in the United States and those proposed for the future. This report documents the Phase III effort on each of the subprograms. For clarity, the report is divided in sections by subprogram as follows: Section 2, Subprogram A - passive barriers/spray air movers for dust control; Section 3, Subprogram B - practical aspects of deep cutting; Section 4, Subprogram C - stage loader dust control; Section 5, Subprogram D - longwall automation technology; Section 6, Subprogram E - longwall application of ventilation curtains; Section 7, Subprogram F - reversed drum rotation; Section 8, Subprogram G - reduction of shield generated dust; Section 9, Subprogram H - air canopies for longwalls; and Section 10, Subprogram I - mining practices. 43 figures, 11 tables.

  2. Extraplanar Dust in Spiral Galaxies: Observations and Implications

    E-Print Network [OSTI]

    J. Christopher Howk

    1999-10-05T23:59:59.000Z

    Recent optical and submillimeter observations have begun to probe the existence of dust grains in the halos of spiral galaxies. I review our own work in this area which employs high-resolution optical images of edge-on spiral galaxies to trace high-z dust in absorption against the background stellar light of the galaxies. We have found that a substantial fraction of such galaxies (>50%) show extensive webs of dust-bearing clouds to heights z>2 kpc. Extraplanar dust in galaxies is statistically correlated with extraplanar diffuse ionized gas, though there is no evidence for a direct, physical relationship between these two phases of the high-z interstellar medium. The dense high-z clouds individually have masses estimated to be >10^5} to 10^6 solar masses. The detailed properties of the observed dust structures suggest the clouds seen in our images may represent the dense phase of a multiphase ISM at high-z. Such dense clouds can have an important effect on the observed light distribution in spiral galaxies. I discuss the effects such high-z dust can have on quantitative measures of the vertical structure of stars and ionized gas in edge-on systems.

  3. Understanding environmental leachability of electric arc furnace dust

    SciTech Connect (OSTI)

    Stegemann, J.A.; Roy, A.; Caldwell, R.J.; Schilling, P.J.; Tittsworth, R.

    2000-02-01T23:59:59.000Z

    Dust from production of steel in an electric arc furnace (EAF) contains a mixture of elements that pose a challenge for both recovery and disposal. This paper relates the leachability of six Canadian EAF dusts in four leaching tests [distilled water, Ontario Regulation 347 Leachate Extraction Procedure, Amount Available for Leaching (AALT), and pH 5 Stat] to their mineralogy. Chromium and nickel contaminants in EAF dust are largely unleachable (<5% available in AALT and pH 5 Stat), as they are found with the predominant spinel ferrite phase in EAF dust. However, even a small proportion of oxidized chromium can result in significant leachate concentrations of highly toxic chromate. The leachability of zinc (7--50% available), lead (2--17% available), and cadmium (9--55% available) can be significant, as large fractions of these contaminants are found as chlorides and oxides. The leaching of these metals is largely controlled by pH. The acid neutralization capacity of the EAF dusts appeared to be controlled by dissolution of lime and zincite, and results from regulatory leaching tests can be misleading because the variable acid neutralization capacity of EAF dusts can lead to very different final leachate pHs (5--12.4). A more informative approach would be to evaluate the total amounts of contaminants available in the long term, and the acid neutralization capacity.

  4. Floating potential of large dust grains with electron emission

    SciTech Connect (OSTI)

    Bacharis, M., E-mail: minas.bacharis03@imperial.ac.uk [Blackett Laboratory, Imperial College, Prince Consort Road, London SW7 2BW (United Kingdom)

    2014-07-15T23:59:59.000Z

    Electron emission from the surface of solid particles plays an important role in many dusty plasma phenomena and applications. Examples of such cases include fusion plasmas and dusty plasma systems in our solar system. Electron emission complicates the physics of the plasma-dust interaction. One of the most important aspects of the physics of the dust plasma interaction is the calculation of the particle's floating potential. This is the potential a dust particle acquires when it is in contact with a plasma and it plays a very important role for determining its dynamical behaviour. The orbital motion limited (OML) approach is used in most cases in the literature to model the dust charging physics. However, this approach has severe limitations when the size of the particles is larger than the electron Debye length ?{sub De}. Addressing this shortcoming for cases without electron emission, a modified version of OML (MOML) was developed for modelling the charging physics of dust grains larger than the electron Debye length. In this work, we will focus on extending MOML in cases where the particles emit electrons. Furthermore, a general method for calculating the floating potential of dust particles with electron emission will be presented for a range of grain sizes.

  5. Development of materials resistant to metal dusting degradation.

    SciTech Connect (OSTI)

    Natesan, K.; Zeng, Z.

    2006-04-24T23:59:59.000Z

    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.

  6. HTGR Dust Safety Issues and Needs for Research and Development

    SciTech Connect (OSTI)

    Paul W. Humrickhouse

    2011-06-01T23:59:59.000Z

    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.

  7. The effect of aging on smoke optical properties and scavenging characteristics

    SciTech Connect (OSTI)

    Penner, J.E.

    1986-11-01T23:59:59.000Z

    Aging of smoke in dense smoke plumes is known to alter its size distribution and scavenging characteristics. In this paper, I review data pertaining to these processes and compare them to model simulations of the coagulation of smoke. Model simulations of the degree of smoke coagulation in the first few days after a nuclear war are summarized. The predicted size of smoke particles after several days of coagulation is found to be larger than that of any data pertaining to the absorption properties of smoke. Thus, it is suggested that more relevant data on the absorption properties of smoke is needed. I also review aging experiments pertaining to the number of cloud condensation nuclei in a smoke sample. I show that the fraction of smoke particles which act as CCN after aging depends on the number of particles initially present in the aging chamber. Smoke from an acetylene flame can quickly coagulate to sizes wherein nearly all of the particles act as CCN. On the other hand, only 10% of the smoke particles from an outdoor fire of gasoline and diesel fuel became CCN after 30 hours of aging. The development of CCN concentrations in this experiment may have been quenched by low initial concentrations in the aging chamber. Both experiments are consistent with particles as small as 0.08 micron in radius (and perhaps even smaller) acting as CCN. Model simulations of the coagulation of smoke particles above a large, intense fire show that coagulation would allow approximately 50% of the particles to become larger than 0.08 micron before the plume reaches cloud base. Furthermore, aging over several days time would transform nearly all the particles into the scavengable size range.

  8. Toward resolution-independent dust emissions in global models: Impacts on the seasonal and spatial distribution of dust

    E-Print Network [OSTI]

    Pierce, J. R.

    Simulating the emission of mineral dust and sea-salt aerosol is nonlinear with surface winds and therefore requires accurate representation of surface winds. Consequently, the resolution of a simulation affects emission ...

  9. The Absence of Cold Dust and the Mineralogy and Origin of the Warm Dust Encircling BD +20 307

    E-Print Network [OSTI]

    Weinberger, A J; Song, I; Zuckerman, B

    2010-01-01T23:59:59.000Z

    Spitzer Space Telescope photometry and spectroscopy of BD +20 307 show that all of the dust around this remarkable Gyr-old spectroscopic binary arises within 1 AU. No additional cold dust is needed to fit the infrared excess. Peaks in the 10 and 20 micron spectrum are well fit with small silicates that should be removed on a timescale of years from the system. This is the dustiest star known for its age, which is >1 Gyr. The dust cannot arise from a steady-state collisional cascade. A catastrophic collision of two rocky, planetary-scale bodies in the terrestrial zone is the most likely source for this warm dust because it does not require a reservoir of planetesimals in the outer system.

  10. THE ABSENCE OF COLD DUST AND THE MINERALOGY AND ORIGIN OF THE WARM DUST ENCIRCLING BD +20 307

    SciTech Connect (OSTI)

    Weinberger, A. J. [Department of Terrestrial Magnetism, Carnegie Institution of Washington 5241 Broad Branch Road NW, Washington, DC 20015 (United States); Becklin, E. E.; Zuckerman, B. [Department of Physics and Astronomy, University of California Los Angeles, Box 951547, Los Angeles, CA 90095-1562 (United States); Song, I., E-mail: weinberger@dtm.ciw.edu, E-mail: becklin@astro.ucla.edu, E-mail: ben@astro.ucla.edu, E-mail: song@uga.edu [Department of Physics and Astronomy, University of Georgia, Athens, GA 30602-2451 (United States)

    2011-01-10T23:59:59.000Z

    Spitzer Space Telescope photometry and spectroscopy of BD +20 307 show that all of the dust around this remarkable Gyr-old spectroscopic binary arises within 1 AU. No additional cold dust is needed to fit the infrared excess. Peaks in the 10 and 20 {mu}m spectrum are well fit with small silicates that should be removed on a timescale of years from the system. This is the dustiest star known for its age, which is {approx}>1 Gyr. The dust cannot arise from a steady-state collisional cascade. A catastrophic collision of two rocky, planetary-scale bodies in the terrestrial zone is the most likely source for this warm dust because it does not require a reservoir of planetesimals in the outer system.

  11. EAF dust as an electrolytic zinc resource

    SciTech Connect (OSTI)

    Zunkel, A.D. [A.D. Zunkel Consultants Inc., Vancouver, WA (United States)

    1995-12-31T23:59:59.000Z

    Two viable options are presently available to the electrolytic zinc producer to supplement the zinc production capability significantly by using electric arc furnace dust (EAFD) or leady ZnO products derived from EAFD: Integrated processing of the materials using the Modified Zincex Process and commingling the zinc sulfate solution from that process with the neutral solution from the calcine leaching circuit; Installing a completely separate circuit for treating the material using technologies such as the Modified Zincex or Esinex Processes. EAFD and halogen-bearing EAFD derived products are a zinc resource which is virtually untapped by new or existing electrolytic zinc producers and which offers them, with the advent of new technologies able to deal with halides, the opportunity to maintain or increase their zinc production from a relatively cheap, if not ``free``, and already mined zinc source. Such an approach would also provide the EAFD producer an alternative, perhaps lower cost, outlet for their material to the currently rather closely held EAFD processing industry.

  12. High density matter

    E-Print Network [OSTI]

    J. R. Stone

    2013-02-11T23:59:59.000Z

    The microscopic composition and properties of matter at super-saturation densities have been the subject of intense investigation for decades. The scarcity of experimental and observational data has lead to the necessary reliance on theoretical models. However, there remains great uncertainty in these models, which, of necessity, have to go beyond the over-simple assumption that high density matter consists only of nucleons and leptons. Heavy strange baryons, mesons and quark matter in different forms and phases have to be included to fulfil basic requirements of fundamental laws of physics. In this review the latest developments in construction of the Equation of State (EoS) of high-density matter at zero and finite temperature assuming different composition of the matter are surveyed. Critical comparison of model EoS with available observational data on neutron stars, including gravitational masses, radii and cooling patterns is presented. The effect of changing rotational frequency on the composition of neutron stars during their lifetime is demonstrated. Compatibility of EoS of high-density, low temperature compact objects and low density, high temperature matter created in heavy-ion collisions is discussed.

  13. Smoking and Ischemic Heart Disease Disparities Between Studies, Genders, Times, and Socioeconomic Strata

    E-Print Network [OSTI]

    Leistikow, Bruce N.

    2009-01-01T23:59:59.000Z

    predictors of coronary heart disease among women. Americanon the risk for coronary heart disease even stronger thanx Smoking and Ischemic Heart Disease Disparities Between

  14. Global impact of smoke aerosols from landscape fires on climate and the Hadley circulation

    E-Print Network [OSTI]

    Tosca, M. G; Randerson, J. T; Zender, C. S

    2013-01-01T23:59:59.000Z

    smoke clouds associated with peat and deforestation fires inforest, agricultural, and peat fires (1997– 2009), Atmos.of carbon released from peat and forest fires in Indonesia

  15. Soluble and insoluble lithium dust in the EPICA DomeC ice core--Implications for changes of the East Antarctic dust

    E-Print Network [OSTI]

    Fischer, Hubertus

    Soluble and insoluble lithium dust in the EPICA DomeC ice core--Implications for changes Editor: G.D. Price Available online 16 March 2007 Abstract Continental dust impurities in Antarctic ice with special emphasis on the lithium (Li) content of dust. We obtained two complementary Li-records using a new

  16. ENRICHMENT OF THE DUST-TO-GAS MASS RATIO IN BONDI/JEANS ACCRETION/CLOUD SYSTEMS DUE TO UNEQUAL CHANGES IN DUST AND GAS INCOMING VELOCITIES

    E-Print Network [OSTI]

    Bellan, Paul M.

    ENRICHMENT OF THE DUST-TO-GAS MASS RATIO IN BONDI/JEANS ACCRETION/CLOUD SYSTEMS DUE TO UNEQUAL velocity profile from gas so that the dust-to-gas ratio is substantially enriched above the 1% interstellar of motion that the dust-to-gas ratio can become substantially enriched during Bondi- type accretion. Star

  17. Phase transition from hadronic matter to quark matter

    E-Print Network [OSTI]

    P. Wang; A. W. Thomas; A. G. Williams

    2007-04-03T23:59:59.000Z

    We study the phase transition from nuclear matter to quark matter within the SU(3) quark mean field model and NJL model. The SU(3) quark mean field model is used to give the equation of state for nuclear matter, while the equation of state for color superconducting quark matter is calculated within the NJL model. It is found that at low temperature, the phase transition from nuclear to color superconducting quark matter will take place when the density is of order 2.5$\\rho_0$ - 5$\\rho_0$. At zero density, the quark phase will appear when the temperature is larger than about 148 MeV. The phase transition from nuclear matter to quark matter is always first order, whereas the transition between color superconducting quark matter and normal quark matter is second order.

  18. Transport of smoke from the Central American Fires of 1998

    E-Print Network [OSTI]

    Rogers, Christopher Matthias

    2000-01-01T23:59:59.000Z

    index image for April 8, 1998. 22 TOMS aerosol index image for April 17, 1998. 23 TOMS aerosol index image for May 9, 1998 . . 25 TOMS aerosol index image for May 15, 1998. 26 10 TOMS aerosol index image for May 17, 1998. 28 TOMS aerosol index image... Index April 17, 1998 10N . . 1 10W. . . LOOW. . . 1. 5 2. 5 3. 5 4. 5 5. 5 N-Value Resrdue 6. 5 7. 5 Figure 7. TOMS aerosol index image for April 17, 1998. 24 near Galveston. In general, most of the smoke remained over the Gulf of Mexico during...

  19. Thermodynamics of clusterized matter

    E-Print Network [OSTI]

    Ad. R. Raduta; F. Gulminelli

    2009-08-26T23:59:59.000Z

    Thermodynamics of clusterized matter is studied in the framework of statistical models with non-interacting cluster degrees of freedom. At variance with the analytical Fisher model, exact Metropolis simulation results indicate that the transition from homogeneous to clusterized matter lies along the $\\rho=\\rho_0$ axis at all temperatures and the limiting point of the phase diagram is not a critical point even if the surface energy vanishes at this point. Sensitivity of the inferred phase diagram to the employed statistical framework in the case of finite systems is discussed by considering the grand-canonical and constant-pressure canonical ensembles. A Wigner-Seitz formalism in which the fragment charge is neutralized by an uniform electron distribution allows to build the phase diagram of neutron star matter.

  20. Axion Dark Matter Searches

    E-Print Network [OSTI]

    I. Stern

    2014-03-21T23:59:59.000Z

    Nearly all astrophysical and cosmological data point convincingly to a large component of cold dark matter in the Universe. The axion particle, first theorized as a solution to the strong charge-parity problem of quantum chromodynamics, has been established as a prominent CDM candidate. Cosmic observation and particle physics experiments have bracketed the unknown mass of the axion between approximately a $\\mu$eV and a meV. The Axion Dark Matter eXperiement (ADMX) has successfully completed searches between 1.9 and 3.7 $\\mu$eV down to the KSVZ photon-coupling limit. ADMX and the Axion Dark Matter eXperiement High-Frequency (ADMX-HF) will search for axions at weaker coupling and/or higher frequencies within the next few years. Status of the experiments, current research and development, and projected mass-coupling exclusion limits are presented.

  1. Axion dark matter searches

    SciTech Connect (OSTI)

    Stern, Ian P. [Department of Physics, Univerisity of Florida, Gainesville, FL 32611-8440 (United States); Collaboration: ADMX Collaboration; ADMX-HF Collaboration

    2014-06-24T23:59:59.000Z

    Nearly all astrophysical and cosmological data point convincingly to a large component of cold dark matter in the Universe. The axion particle, first theorized as a solution to the strong charge-parity problem of quantum chromodynamics, has been established as a prominent CDM candidate. Cosmic observation and particle physics experiments have bracketed the unknown mass of the axion between approximately a ?eV and a meV. The Axion Dark Matter eXperiement (ADMX) has successfully completed searches between 1.9 and 3.7 ?eV down to the KSVZ photon-coupling limit. ADMX and the Axion Dark Matter eXperiement High-Frequency (ADMX-HF) will search for axions at weaker coupling and/or higher frequencies within the next few years. Status of the experiments, current research and development, and projected mass-coupling exclusion limits are presented.

  2. ADVANCES IN DUST DETECTION AND REMOVAL FOR TOKAMAKS

    SciTech Connect (OSTI)

    Campos, A.; Skinner, C.H.

    2009-01-01T23:59:59.000Z

    Dust diagnostics and removal techniques are vital for the safe operation of next step fusion devices such as ITER. In the tokamak environment, large particles or fi bers can fall on the electrostatic detector potentially causing a permanent short. An electrostatic dust detector developed in the laboratory is being applied to the National Spherical Torus Experiment (NSTX). We report on the development of a gas puff system that uses helium to clear such particles from the detector. Experiments at atmospheric pressure with varying nozzle designs, backing pressures, puff durations and exit fl ow orientations have given an optimal confi guration that effectively removes particles from a 25 cm² area. Similar removal effi ciencies were observed under a vacuum base pressure of 1 mTorr. Dust removal from next step tokamaks will be required to meet regulatory dust limits. A tri-polar grid of fi ne interdigitated traces has been designed that generates an electrostatic traveling wave for conveying dust particles to a “drain.” First trials with only two working electrodes have shown particle motion in optical microscope images.

  3. The Impact of Dust Evolution and Photoevaporation on Disk Dispersal

    E-Print Network [OSTI]

    Gorti, Uma; Dullemond, Cornelis

    2015-01-01T23:59:59.000Z

    Protoplanetary disks are dispersed by viscous evolution and photoevaporation in a few million years; in the interim small, sub-micron sized dust grains must grow and form planets. The time-varying abundance of small grains in an evolving disk directly affects gas heating by far-ultraviolet photons, while dust evolution affects photoevaporation by changing the disk opacity and resulting penetration of FUV photons in the disk. Photoevaporative flows, in turn, selectively carry small dust grains leaving the larger particles---which decouple from the gas---behind in the disk. We study these effects by investigating the evolution of a disk subject to viscosity, photoevaporation by EUV, FUV and X-rays, dust evolution, and radial drift using a 1-D multi-fluid approach (gas + different dust grain sizes) to solve for the evolving surface density distributions. The 1-D evolution is augmented by 1+1D models constructed at each epoch to obtain the instantaneous disk structure and determine photoevaporation rates. The imp...

  4. Microchemical investigations of dust emitted by a lead smelter

    SciTech Connect (OSTI)

    Sobanska, S.; Ricq, N. [Ecole des Mines de Douai (France). Dept. Chimie et Environnement] [Ecole des Mines de Douai (France). Dept. Chimie et Environnement; [Univ. de Lille I, Villeneuve d`Ascq (France); Laboudigue, A.; Guillermo, R. [Ecole des Mines de Douai (France). Dept. Chimie et Environnement] [Ecole des Mines de Douai (France). Dept. Chimie et Environnement; Bremard, C.; Laureyns, J.; Merlin, J.C.; Wignacourt, J.P. [Univ. de Lille I, Villeneuve d`Ascq (France)] [Univ. de Lille I, Villeneuve d`Ascq (France)

    1999-05-01T23:59:59.000Z

    Dusts emitted by an important pyrometallurgical lead smelter have been sampled within the pipes of the grilling and furnace working units before and after the filtering systems, respectively. Particle size distribution, elementary analyses, and X-ray powder diffraction analysis indicate PbS, PbSO{sub 4}, PbSO{sub 4}{center_dot}PbO, Pb, ZnS small particles less than 5 {micro}m in size to contribute mainly to the current atmospheric pollution. Although at least 90% of dust are retained on the filters, the amounts of the respirable smaller particles are significantly larger in the current emission. The average chemical speciation was found to be analogous for the dust samples collected before and after the filters. The scanning electron microscopy associated with energy-dispersive X-ray analysis and Raman microspectrometry established the morphology and chemical composition at the level of individual particles. A lot of minor compounds were found as small heterogeneous individual particles in the heterogeneous particles of grilling dust. Among the homogeneous particles of furnace dust, amorphous C, {beta}-PbO, PbO-PbCl{sub 2}, FeO, CdS, CdSO{sub 4} were often detected as homogeneous mixtures with the major compounds within the particles.

  5. Dust properties inside molecular clouds from coreshine modeling and observations

    E-Print Network [OSTI]

    Lefèvre, Charlène; Juvela, Mika; Paladini, Roberta; Lallement, Rosine; Marshall, D J; Andersen, Morten; Bacmann, Aurore; Mcgee, Peregrine M; Montier, Ludovic; Noriega-Crespo, Alberto; Pelkonen, V -M; Ristorcelli, Isabelle; Steinacker, Jürgen

    2014-01-01T23:59:59.000Z

    Context. Using observations to deduce dust properties, grain size distribution, and physical conditions in molecular clouds is a highly degenerate problem. Aims. The coreshine phenomenon, a scattering process at 3.6 and 4.5 $\\mu$m that dominates absorption, has revealed its ability to explore the densest parts of clouds. We want to use this effect to constrain the dust parameters. The goal is to investigate to what extent grain growth (at constant dust mass) inside molecular clouds is able to explain the coreshine observations. We aim to find dust models that can explain a sample of Spitzer coreshine data. We also look at the consistency with near-infrared data we obtained for a few clouds. Methods. We selected four regions with a very high occurrence of coreshine cases: Taurus-Perseus, Cepheus, Chameleon and L183/L134. We built a grid of dust models and investigated the key parameters to reproduce the general trend of surface bright- nesses and intensity ratios of both coreshine and near-infrared observation...

  6. Rotary rail car dumper coal-dust-suppressant experiment

    SciTech Connect (OSTI)

    Meyer, J.H.; Hereford, L.G.; Lenkevich, M.J.

    1984-10-01T23:59:59.000Z

    A rotary rail car dumper dust-suppressant experiment was performed at the PEPCO Morgantown Power Plant coal handling facility, Newburg, Maryland during the late summer and early fall of 1983. From previous observations of rotary coal car dumping, it was observed that large amounts of dust, especially for washed coal, were generated from the exposed top layer of coal in the open rail car. An overhead spray system using water and surfactant was used to examine the effectiveness of surface wetting just before dumping. High volume sampling at both the entrance and exit doorways of the dumper shed was used to determine the coal dust reduction. A total of 23 tests was performed, of which 16 tests were considered valid. All data were normalized for background, number of tons dumped and sampling time. The use of an overhead spray system can substantially suppress fugitive coal dust generated by rotary rail car dumping of coal. A water and surfactant mixture provided coal-dust-suppressant efficiencies ranging from 47% to 79% with an average of 61% for a combination of washed, mixed, and unwashed coal.

  7. Coal home heating and environmental tobacco smoke in relation to lower respiratory illness in Czech children, from birth to 3 years of age

    E-Print Network [OSTI]

    2006-01-01T23:59:59.000Z

    still com- monly used in home heating and smoking rates arefound exposure to coal home heating and ETS increase youngcigarette smoke, coal heating, and respiratory symptoms of

  8. We need you, Yul Brynner! "Now that I'm gone, I tell you: Don't smoke, whatever you do, just don't smoke."

    E-Print Network [OSTI]

    Hernes, Peter J.

    flatlands, looking for the UC Davis 8%, the coughing scallywags. He is our spectral smoke alarm. Yul Brynner and coughing in the shrubbery, their passions seeping out like a million etceteras. #12;

  9. Responsibility and resistance : children and young people’s accounts of smoking in the home and car 

    E-Print Network [OSTI]

    Rowa-Dewar, Neneh

    2013-07-06T23:59:59.000Z

    Following the implementation of the smokefree law in 2006, which formed part of the Smoking, Health and Social Care (Scotland) Act 2005, smoking in enclosed public spaces has been prohibited in Scotland. The law has led ...

  10. Infant Formula with Docosahexaenoic Acid, Maternal Smoking, and Body Mass Index of Children To Six Years of Age

    E-Print Network [OSTI]

    Currie, Lindsey Marie

    2012-05-31T23:59:59.000Z

    Research findings have suggested no differences in growth among term infants fed DHA supplemented formulas. Studies have found maternal smoking decreases length and increases weight of children. No studies have analyzed maternal smoking and DHA...

  11. Influence of solar heating and precipitation scavenging on the simulated lifetime of post-nuclear war smoke

    SciTech Connect (OSTI)

    Malone, R.C.; Auer, L.H.; Glatzmaier, G.A.; Wood, M.C.; Toon, O.B.

    1985-10-18T23:59:59.000Z

    The behavior of smoke injected into the atmosphere by massive fires that might follow a nuclear war was simulated. Studies with a three-dimensional global atmospheric circulation model showed that heating of the smoke by sunlight would be important and might produce several effects that would decrease the efficiency with which precipitation removes smoke well above the original injection height. Heating of the smoke also causes the tropopause, which is initially above the smoke, to reform below the heated smoke layer. Smoke above the tropopause is physically isolated from precipitation below. Consequently, the atmospheric residence time of the remaining smoke is greatly increased over the prescribed residence times used in previous models of nuclear winter. 13 references, 3 figures.

  12. MATERNAL COFFEE AND ALCOHOL CONSUMPTION DURING PREGNANCY, PARENTAL SMOKING AND RISK OF CHILDHOOH ACUTE LEUKEMIA

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACUTE LEUKEMIA Short title: Maternal coffee and alcohol consumption, parental smoking and childhood smoking and maternal beverage consumption, were obtained for 280 cases of childhood acute leukemia and 280 acute leukemia in a multicenter case-control study. The study included 280 incident cases and 288

  13. Use of a Soluble Epoxide Hydrolase Inhibitor in Smoke-Induced Chronic Obstructive Pulmonary Disease

    E-Print Network [OSTI]

    Hammock, Bruce D.

    of the lungs character- ized by progressive and largely irreversible airflow limitation attribu- table) to reduce lung injury and inflammation after subacute exposure to tobacco smoke over a period of 4 weeks lavage. sEHI t-TUCB suppressed IFN-g, while improving lung function by reducing tobacco smoke

  14. Attenuation of tobacco smoke-induced lung inflammation by treatment with a soluble epoxide

    E-Print Network [OSTI]

    Hammock, Bruce D.

    Attenuation of tobacco smoke-induced lung inflammation by treatment with a soluble epoxide, December 21, 2004 Changes in the lungs due to smoking include inflammation, epi- thelial damage inflammation in the lungs. Soluble epoxide hydrolases (sEH) are enzymes that add water to epoxides forming

  15. Smoke and toxic species analyses from controlled combustion of wood impregnated with guayule resin

    E-Print Network [OSTI]

    Smith, Lonnie

    1995-01-01T23:59:59.000Z

    . untreated samples. Flame spread was measured after ignition with a propane flame by a simple stopwatch-ruler technique. Smoke mass was determined in an Arapahoe Smoke Chamber as per ASTM D-4100. Analysis of the fumes involved continuous CO, C02, NOx, SOx...

  16. Polycyclic Aromatic Hydrocarbons Present in Cigarette Smoke Cause Bone Loss in an Ovariectomized Rat Model

    E-Print Network [OSTI]

    Waldman, Stephen D.

    of epidemiological studies have suggested that cigarette smoking is a risk factor for osteoporosis. Benzo- (a and fragility seen in smoking-related osteoporosis. In this study four groups of 9-month-old Sprague-Dawley rats; Ovariectomy (ovx); Estrogen; Osteoporosis. Introduction Epidemiological studies have focused

  17. Dynamics of fire plumes and smoke clouds associated with peat and deforestation fires in Indonesia

    E-Print Network [OSTI]

    Zender, Charles

    Dynamics of fire plumes and smoke clouds associated with peat and deforestation fires in Indonesia), Dynamics of fire plumes and smoke clouds associated with peat and deforestation fires in Indonesia, J. Geophys. Res., 116, D08207, doi:10.1029/2010JD015148. 1. Introduction [2] Peat and deforestation fires

  18. Realistic Smoke Simulation Using A Frustum Aligned Alan Wai Lun Woo

    E-Print Network [OSTI]

    Bridson, Robert

    . The grid is logically rectangular and a perspective transformation can map the grid into a spatiallyRealistic Smoke Simulation Using A Frustum Aligned Grid by Alan Wai Lun Woo B.Sc., University utilize uniformly spaced rectangular computational grids to perform the smoke simulation. Various changes

  19. mPuff: Automated Detection of Cigarette Smoking Puffs from Respiration Measurements

    E-Print Network [OSTI]

    Kumar, Santosh

    that accounts for one in five deaths in the United States. Extensive research is conducted on devel- oping deaths in the United States [24]. Smokers die 13-14 years younger and cost $193 billion annually [1 effective smoking cessation programs. Most smoking cessation programs achieve low success rate because

  20. Elasticity of a percolation system: silica smoke J. FORSMAN',J. P. HARRISON,AND A. RUTENBERG'

    E-Print Network [OSTI]

    Rutenberg, Andrew

    of colloids (aerogels) (4), condensed smoke ( 3 , composite for- mation (6), or sintering of metal powder (7

  1. Migration of Artificially Introduced Micron Size Carbon Dust in the DIII-D Divertor

    SciTech Connect (OSTI)

    Rudakov, D; West, W; Wong, C; Brooks, N; Evans, T; Fenstermacher, M; Groth, M; Krasheninnikov, S; Lasnier, C; McLean, A; Pigarov, A Y; Solomon, W; Antar, G; Boedo, J; Doerner, R; Hollmann, E; Hyatt, A; Maingi, R; Moyer, R; Nagy, A; Nishino, N; Roquemore, L; Stangeby, P; Watkins, J

    2006-05-15T23:59:59.000Z

    Migration of pre-characterized carbon dust in a tokamak environment was studied by introducing about 30 milligrams of dust flakes 5-10 {micro}m in diameter in the lower divertor of DIII-D using the DiMES sample holder. The dust was exposed to high power ELMing Hmode discharges in lower-single-null magnetic configuration with the strike points swept across the divertor floor. When the outer strike point (OSP) passed over the dust holder exposing it to high particle and heat fluxes, part of the dust was injected into the plasma. In about 0.1 sec following the OSP pass over the dust, 1-2% of the total dust carbon content (2-4 x 10{sup 19} carbon atoms, equivalent to a few million dust particles) penetrated the core plasma, raising the core carbon density by a factor of 2-3. When the OSP was inboard of the dust holder, the dust injection continued at a lower rate. Individual dust particles were observed moving at velocities of 10-100 m/s, predominantly in the toroidal direction for deuteron flow to the outer divertor target, consistent with the ion drag force. The observed behavior of the dust is in qualitative agreement with modeling by the 3D DustT code.

  2. VARIABLE WINDS AND DUST FORMATION IN R CORONAE BOREALIS STARS

    SciTech Connect (OSTI)

    Clayton, Geoffrey C.; Zhang Wanshu [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Geballe, T. R., E-mail: gclayton@fenway.phys.lsu.edu, E-mail: wzhan21@lsu.edu, E-mail: tgeballe@gemini.edu [Gemini Observatory, 670 N. A'ohoku Place, Hilo, HI 96720 (United States)

    2013-08-01T23:59:59.000Z

    We have observed P-Cygni and asymmetric, blue-shifted absorption profiles in the He I {lambda}10830 lines of 12 R Coronae Borealis stars over short (1 month) and long (3 yr) timescales to look for variations linked to their dust-formation episodes. In almost all cases, the strengths and terminal velocities of the line vary significantly and are correlated with dust formation events. Strong absorption features with blue-shifted velocities {approx}400 km s{sup -1} appear during declines in visible brightness and persist for about 100 days after recovery to maximum brightness. Small residual winds of somewhat lower velocity are present outside of the decline and recovery periods. The correlations support models in which recently formed dust near the star is propelled outward at high speed by radiation pressure and drags the gas along with it.

  3. Lithium Wall Conditioning And Surface Dust Detection On NSTX

    SciTech Connect (OSTI)

    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

    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

  4. Dark matter axions `96

    SciTech Connect (OSTI)

    Sikivie, P.

    1996-12-31T23:59:59.000Z

    This report discusses why axions have been postulated to exist, what cosmology implies about their presence as cold dark matter in the galactic halo, how axions might be detected in cavities wherein strong magnetic fields stimulate their conversion into photons, and relations between axions` energy spectra and galactic halos` properties.

  5. Matter & Energy Solar Energy

    E-Print Network [OSTI]

    Rogers, John A.

    See Also: Matter & Energy Solar Energy· Electronics· Materials Science· Earth & Climate Energy at the University of Illinois, the future of solar energy just got brighter. Although silicon is the industry Electronics Over 1.2 Million Electronics Parts, Components and Equipment. www.AlliedElec.com solar energy

  6. Matter & Energy Engineering

    E-Print Network [OSTI]

    Sóbester, András

    .com/products/seahawk/ Maryland Solar Panels-- Solar Installations from BGE HOME $0 Down For Big Energy Savings! www.bgehome.com/SolarLike 6 0 | More APA MLA See Also: Matter & Energy Petroleum Engineering Fossil Fuels Earth believe may be contributing to global warming. The UK government has just announced it is investing £1

  7. Asymmetric condensed dark matter

    E-Print Network [OSTI]

    Aguirre, Anthony

    2015-01-01T23:59:59.000Z

    We explore the viability of a boson dark matter candidate with an asymmetry between the number densities of particles and antiparticles. A simple thermal field theory analysis confirms that, under certain general conditions, this component would develop a Bose-Einstein condensate in the early universe that, for appropriate model parameters, could survive the ensuing cosmological evolution until now. The condensation of a dark matter component in equilibrium with the thermal plasma is a relativistic process, hence the amount of matter dictated by the charge asymmetry is complemented by a hot relic density frozen out at the time of decoupling. Contrary to the case of ordinary WIMPs, dark matter particles in a condensate can be very light, $10^{-22}\\,{\\rm eV} \\lesssim m \\lesssim 10^2\\,{\\rm eV}$; the lower limit arises from constraints on small-scale structure formation, while the upper bound ensures that the density from thermal relics is not too large. Big-Bang nucleosynthesis constrains the temperature of deco...

  8. Reconciliation of Zero-Point and Dark Energies in a Friedman Dust Universe with Einstein's Lambda

    E-Print Network [OSTI]

    James G. Gilson

    2010-07-20T23:59:59.000Z

    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.

  9. Energy Matters in Washington State Page 1 Energy Matters

    E-Print Network [OSTI]

    Collins, Gary S.

    Energy Matters in Washington State ­ Page 1 Energy Matters in Washington State June 2008 Updated November 2009 Updated and Revised October 2013 Grand Coulee Dam #12;Energy Matters in Washington State ­ Page 2 Copyright © 2013 Washington State University Energy Program. 905 Plum Street SE, P.O. Box 43169

  10. 3D gravity with dust: classical and quantum theory

    E-Print Network [OSTI]

    Viqar Husain; Jonathan Ziprick

    2015-06-02T23:59:59.000Z

    We study the Einstein gravity and dust system in three spacetime dimensions as an example of a non-perturbative quantum gravity model with local degrees of freedom. We derive the Hamiltonian theory in the dust time gauge and show that it has a rich class of exact solutions. These include the Ba\\~nados-Teitelboim-Zanelli black hole, static solutions with naked singularities and travelling wave solutions with dynamical horizons. We give a complete quantization of the wave sector of the theory, including a definition of a self-adjoint spacetime metric operator. This operator is used to demonstrate the quantization of deficit angle and the fluctuation of dynamical horizons.

  11. What controls the recent changes in African mineral dust aerosol across the Atlantic?

    E-Print Network [OSTI]

    Ridley, David Andrew

    Dust from Africa strongly perturbs the radiative balance over the Atlantic, with emissions that are highly variable from year to year. We show that the aerosol optical depth (AOD) of dust over the mid-Atlantic observed by ...

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

    E-Print Network [OSTI]

    Ai, Ning, 1978-

    2003-01-01T23:59:59.000Z

    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 ...

  13. Effect of argon addition on plasma parameters and dust charging in hydrogen plasma

    SciTech Connect (OSTI)

    Kakati, B., E-mail: bharatkakati15@gmail.com; Kausik, S. S.; Saikia, B. K. [Centre of Plasma Physics-Institute for Plasma Research, Nazirakhat, Sonapur, Kamrup 782402, Assam (India); Bandyopadhyay, M.; Saxena, Y. C. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India)

    2014-10-28T23:59:59.000Z

    Experimental results on effect of adding argon gas to hydrogen plasma in a multi-cusp dusty plasma device are reported. Addition of argon modifies plasma density, electron temperature, degree of hydrogen dissociation, dust current as well as dust charge. From the dust charging profile, it is observed that the dust current and dust charge decrease significantly up to 40% addition of argon flow rate in hydrogen plasma. But beyond 40% of argon flow rate, the changes in dust current and dust charge are insignificant. Results show that the addition of argon to hydrogen plasma in a dusty plasma device can be used as a tool to control the dust charging in a low pressure dusty plasma.

  14. Mineral content analysis of atmospheric dust using hyperspectral information from space

    E-Print Network [OSTI]

    Kostinski, Alex

    Mineral content analysis of atmospheric dust using hyperspectral information from space A one of the world's largest sources of atmospheric mineral dust. Mineral composition optical properties, and mineral deposition to Amazon forests. In this study we examine hyperspectral

  15. The Development of Measurement Techniques to Identify and Characterize Dusts and Ice Nuclei in the Atmosphere

    E-Print Network [OSTI]

    Glen, Andrew

    2014-01-15T23:59:59.000Z

    Mineral dusts and ice crystals directly influence the Earth's radiative budget through radiative scattering and absorption. The interaction of spherical particles on the radiative budget are well known, however mineral dusts and ice crystals...

  16. Engineering and economic impacts of prohibiting recombination recirculation dust at export elevators

    E-Print Network [OSTI]

    Whitelock, Derek Paul

    1994-01-01T23:59:59.000Z

    The objectives of this research were to develop engineering descriptions of dust control systems currently being used in grain export facilities, to determine the retrofit requirements of the dust control and handling systems to comply...

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

    SciTech Connect (OSTI)

    Carter, C M

    2012-04-25T23:59:59.000Z

    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.

  18. Self assembly in soft matter 

    E-Print Network [OSTI]

    Chremos, Alexandros

    2009-01-01T23:59:59.000Z

    The term “soft matter” applies to a variety of physical systems, such as liquids, colloids, polymers, foams, gels, and granular materials. The most fascinating aspect of soft matter lies in the fact that they are not ...

  19. Self Assembly in Soft Matter 

    E-Print Network [OSTI]

    Chremos, Alexandros

    2009-01-01T23:59:59.000Z

    The term “soft matter” applies to a variety of physical systems, such as liquids, colloids, polymers, foams, gels, and granular materials. The most fascinating aspect of soft matter lies in the fact that they are not ...

  20. The Search for Dark Matter

    ScienceCinema (OSTI)

    Orrell, John

    2014-07-24T23:59:59.000Z

    More than 25 years ago, PNNL scientists began the first underground measurements searching for dark matter using specialized radiation detector technology. Dark matter is yet to be discovered says Physicist John L. Orrell.

  1. The Search for Dark Matter

    SciTech Connect (OSTI)

    Orrell, John

    2013-11-20T23:59:59.000Z

    More than 25 years ago, PNNL scientists began the first underground measurements searching for dark matter using specialized radiation detector technology. Dark matter is yet to be discovered says Physicist John L. Orrell.

  2. DISCOVERY OF 'WARM DUST' GALAXIES IN CLUSTERS AT z {approx} 0.3: EVIDENCE FOR STRIPPING OF COOL DUST IN THE DENSE ENVIRONMENT?

    SciTech Connect (OSTI)

    Rawle, T. D.; Rex, M.; Egami, E.; Walth, G.; Pereira, M. J. [Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Chung, S. M.; Gonzalez, A. H. [Department of Astronomy, University of Florida, Gainesville, FL 32611-2055 (United States); Perez-Gonzalez, P. G. [Departamento de Astrofisica, Facultad de CC. Fisicas,Universidad Complutense de Madrid, E-28040 Madrid (Spain); Smail, I. [Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom); Altieri, B.; Valtchanov, I. [Herschel Science Centre, ESAC, ESA, P.O. Box 78, Villanueva de la Canada, E-28691 Madrid (Spain); Appleton, P.; Fadda, D. [IPAC, California Institute of Technology, Pasadena, CA 91125 (United States); Alba, A. Berciano [ASTRON, Oude Hoogeveensedijk 4, NL-7991 PD Dwingeloo (Netherlands); Blain, A. W. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Dessauges-Zavadsky, M. [Observatoire de Geneve, Universite de Geneve, 51 Ch. des Maillettes, CH-1290 Sauverny (Switzerland); Van der Werf, P. P. [Sterrewacht Leiden, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands); Zemcov, M., E-mail: trawle@as.arizona.edu [Department of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)

    2012-09-10T23:59:59.000Z

    Using far-infrared imaging from the 'Herschel Lensing Survey', we derive dust properties of spectroscopically confirmed cluster member galaxies within two massive systems at z {approx} 0.3: the merging Bullet Cluster and the more relaxed MS2137.3-2353. Most star-forming cluster sources ({approx}90%) have characteristic dust temperatures similar to local field galaxies of comparable infrared (IR) luminosity (T{sub dust} {approx} 30 K). Several sub-luminous infrared galaxy (LIRG; L{sub IR} < 10{sup 11} L{sub Sun }) Bullet Cluster members are much warmer (T{sub dust} > 37 K) with far-infrared spectral energy distribution (SED) shapes resembling LIRG-type local templates. X-ray and mid-infrared data suggest that obscured active galactic nuclei do not contribute significantly to the infrared flux of these 'warm dust' galaxies. Sources of comparable IR luminosity and dust temperature are not observed in the relaxed cluster MS2137, although the significance is too low to speculate on an origin involving recent cluster merging. 'Warm dust' galaxies are, however, statistically rarer in field samples (>3{sigma}), indicating that the responsible mechanism may relate to the dense environment. The spatial distribution of these sources is similar to the whole far-infrared bright population, i.e., preferentially located in the cluster periphery, although the galaxy hosts tend toward lower stellar masses (M{sub *} < 10{sup 10} M{sub Sun }). We propose dust stripping and heating processes which could be responsible for the unusually warm characteristic dust temperatures. A normal star-forming galaxy would need 30%-50% of its dust removed (preferentially stripped from the outer reaches, where dust is typically cooler) to recover an SED similar to a 'warm dust' galaxy. These progenitors would not require a higher IR luminosity or dust mass than the currently observed normal star-forming population.

  3. Dust suppression results using mineral oil applications on corn and milo

    E-Print Network [OSTI]

    Wardlaw, Herman Douglas

    1987-01-01T23:59:59.000Z

    grain dust explosion, grain dust (less than 100 microns (pm) In aerodynamic diameter) must be in suspension at or above the minimum explosive concentration (MEC). The MEC for grain dust will vary depending upon moisture context, particle size... will be present in any grain handling facility. Containment restricts grain dust from dispersing, which allows for the development of the MEC. The NEC is so highly concentrated that without containment, it is unlikely to occur in a grain handling facility...

  4. Normal matter storage of antiprotons

    SciTech Connect (OSTI)

    Campbell, L.J.

    1987-01-01T23:59:59.000Z

    Various simple issues connected with the possible storage of anti p in relative proximity to normal matter are discussed. Although equilibrium storage looks to be impossible, condensed matter systems are sufficiently rich and controllable that nonequilibrium storage is well worth pursuing. Experiments to elucidate the anti p interactions with normal matter are suggested. 32 refs.

  5. dark matter dark energy inflation

    E-Print Network [OSTI]

    Hu, Wayne

    theory dark matter dark energy inflation The National Science Foundation The Kavli Foundation NSF Site Review November 28-29, 2005 #12;dark matter dark energy inflation NSF Site Visit ­ November 28 Gravitation initial conditions beyond single-field slow roll #12;dark matter dark energy inflation NSF Site

  6. Dark Energy and Dark Matter

    E-Print Network [OSTI]

    Keith A. Olive

    2010-01-27T23:59:59.000Z

    A brief overview of our current understanding of abundance and properties of dark energy and dark matter is presented. A more focused discussion of supersymmetric dark matter follows. Included is a frequentist approach to the supersymmetric parameter space and consequences for the direct detection of dark matter.

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

    SciTech Connect (OSTI)

    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

    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.

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

    SciTech Connect (OSTI)

    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

    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.

  9. TITLE: Preliminary Examination of Impact Craters on Al Foil from the Stardust Interstellar Dust Collector

    E-Print Network [OSTI]

    the Stardust Interstellar Dust Collector SESSION TYPE: Poster; SESSION TITLE: P43A. Extraterrestrial Dust@home dusters ABSTRACT BODY: The Interstellar Dust Collector from the NASA Stardust mission provides) stream in order to obtain such information as grain composition and microstructure. The collector

  10. Model bias correction for dust storm forecast using ensemble Kalman filter

    E-Print Network [OSTI]

    Model bias correction for dust storm forecast using ensemble Kalman filter Caiyan Lin,1,2 Jiang Zhu Kalman filter (EnKF) assimilation targeting heavy dust episodes during the period of 15­24 March 2002. Wang (2008), Model bias correction for dust storm forecast using ensemble Kalman filter, J. Geophys

  11. Optical Investigations of Dust Particles Distribution in RF and DC Discharges

    SciTech Connect (OSTI)

    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

    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.

  12. Granular flow in pebble-bed nuclear reactors: Scaling, Dust Generation, and Stress

    E-Print Network [OSTI]

    Rycroft, Chris H.

    Granular flow in pebble-bed nuclear reactors: Scaling, Dust Generation, and Stress Chris H. Keywords: granular flow, dust generation, numerical methods 1. Introduction Pebble-bed nuclear reactors prototypes of pebble-bed reactors, significant quantities of graphite dust have been observed due to rubbing

  13. SAVE THIS | EMAIL THIS | Close 'Smart dust' aims to monitor everything

    E-Print Network [OSTI]

    Lu, Chenyang

    distinguisher, too. A building's thermostat is most likely hard-wired. A smart dust sensor might gaugePowered by SAVE THIS | EMAIL THIS | Close 'Smart dust' aims to monitor everything By John D. Sutter, CNN STORY HIGHLIGHTS 'Smart dust' refers to tiny sensors that would monitor everything on Earth

  14. Atmospheric Environment 40 (2006) 38813897 Field measurements of desert dust deposition in Libya

    E-Print Network [OSTI]

    Clarke, Michèle

    Atmospheric Environment 40 (2006) 3881­3897 Field measurements of desert dust deposition in Libya-based dust monitoring study of three zones across Libya, ranging from the Mediterranean coast to the Sahara studies in North Africa shows that areas of Libya have the highest dust deposition rates on record. r 2006

  15. Dust-rainfall feedbacks in the West African Sahel Wanching Jacquie Hui,1,2

    E-Print Network [OSTI]

    Dust-rainfall feedbacks in the West African Sahel Wanching Jacquie Hui,1,2 Benjamin I. Cook,3 in this region. Citation: Hui, W. J., B. I. Cook, S. Ravi, J. D. Fuentes, and P. D'Odorico (2008), Dust of solar radiation [Lohmann and Feichter, 2005]. [3] Dust aerosols can contribute to surface cooling

  16. NEBULAR FORMATION OF FAYALITIC OLIVINE: INEFFECTIVENESS OF DUST ENRICHMENT. A. V. Fedkin1

    E-Print Network [OSTI]

    Grossman, Lawrence

    NEBULAR FORMATION OF FAYALITIC OLIVINE: INEFFECTIVENESS OF DUST ENRICHMENT. A. V. Fedkin1 and L temperature, and thus in a nebular region more oxidized than solar gas, pre- sumably due to enrichment in dust of regions enriched in dust relative to its complementary gas yields systems more oxidizing than a solar gas

  17. Dust Cooling in Supernova Remnants in the Large Magellanic Cloud

    E-Print Network [OSTI]

    Seok, Ji Yeon; Hirashita, Hiroyuki

    2015-01-01T23:59:59.000Z

    The infrared-to-X-ray (IRX) flux ratio traces the relative importance of dust cooling to gas cooling in astrophysical plasma such as supernova remnants (SNRs). We derive IRX ratios of SNRs in the LMC using Spitzer and Chandra SNR survey data and compare them with those of Galactic SNRs. IRX ratios of all the SNRs in the sample are found to be moderately greater than unity, indicating that dust grains are a more efficient coolant than gas although gas cooling may not be negligible. The IRX ratios of the LMC SNRs are systematically lower than those of the Galactic SNRs. As both dust cooling and gas cooling pertain to the properties of the interstellar medium, the lower IRX ratios of the LMC SNRs may reflect the characteristics of the LMC, and the lower dust-to- gas ratio (a quarter of the Galactic value) is likely to be the most significant factor. The observed IRX ratios are compared with theoretical predictions that yield IRX ratios an order of magnitude larger. This discrepancy may originate from the dearth ...

  18. Proxies and Measurement Techniques for Mineral Dust in

    E-Print Network [OSTI]

    Howat, Ian M.

    and laser-sensing particle detector), soluble ion analysis (ion chromatography and continuous flow analysis. All methods correlate very well among each other, but the ratios of glacial age to Holocene fluxes. Projects dedicated to this, such as DIRTMAP (7), rely on modeling studies and on dust

  19. A SEARCH FOR DUST EMISSION IN THE LEO INTERGALACTIC CLOUD

    SciTech Connect (OSTI)

    Bot, Caroline; Helou, George; Puget, Jeremie [California Institute of Technology, Pasadena, CA 91125 (United States); Latter, William B. [NASA Herschel Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Schneider, Stephen [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Terzian, Yervant [Department of Astronomy/NAIC, Cornell University, Ithaca, NY 14853 (United States)], E-mail: bot@astro.u-strasbg.fr

    2009-08-15T23:59:59.000Z

    We present a search for infrared dust emission associated with the Leo cloud, a large intergalactic cloud in the M96 group. Mid-infrared and far-infrared images were obtained with the InfraRed Array Camera and the Multiband Imaging Photometer for Spitzer on the Spitzer Space Telescope. Our analysis of these maps is done at each wavelength relative to the H I spatial distribution. We observe a probable detection at 8 {mu}m and a marginal detection at 24 {mu}m associated with the highest H I column densities in the cloud. At 70 and 160 {mu}m, upper limits on the dust emission are deduced. The level of the detection is low so that the possibility of a fortuitous cirrus clump or of an overdensity of extragalactic sources along the line of sight cannot be excluded. If this detection is confirmed, the quantities of dust inferred imply a dust-to-gas ratio in the intergalactic cloud up to a few times solar but no less than 1/20 solar. A confirmed detection would therefore exclude the possibility that the intergalactic cloud has a primordial origin. Instead, this large intergalactic cloud could therefore have been formed through interactions between galaxies in the group.

  20. Quaternary soils and dust deposition in southern Nevada and California

    E-Print Network [OSTI]

    Ahmad, Sajjad

    - ern dust in grain size, content of CaCO3 and salt, major oxides, and clay mineralogy; thus favored translocation of clay and CaCO3 from near the surface to deeper in the soil profile. Pre accumulations of silt, clay, and CaCO3 be- gan to inhibit the downward transport of eolian material, but in part

  1. DUST GRAIN EVOLUTION IN SPATIALLY RESOLVED T TAURI BINARIES

    SciTech Connect (OSTI)

    Skemer, Andrew J.; Close, Laird M.; Hinz, Philip M.; Hoffmann, William F.; Males, Jared R. [Steward Observatory, Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States); Greene, Thomas P. [NASA Ames Research Center, Moffett Field, CA 94035 (United States)

    2011-10-10T23:59:59.000Z

    Core-accretion planet formation begins in protoplanetary disks with the growth of small, interstellar medium dust grains into larger particles. The progress of grain growth, which can be quantified using 10 {mu}m silicate spectroscopy, has broad implications for the final products of planet formation. Previous studies have attempted to correlate stellar and disk properties with the 10 {mu}m silicate feature in an effort to determine which stars are efficient at grain growth. Thus far there does not appear to be a dominant correlated parameter. In this paper, we use spatially resolved adaptive optics spectroscopy of nine T Tauri binaries as tight as 0.''25 to determine if basic properties shared between binary stars, such as age, composition, and formation history, have an effect on dust grain evolution. We find with 90%-95% confidence that the silicate feature equivalent widths of binaries are more similar than those of randomly paired single stars, implying that shared properties do play an important role in dust grain evolution. At lower statistical significance, we find with 82% confidence that the secondary has a more prominent silicate emission feature (i.e., smaller grains) than the primary. If confirmed by larger surveys, this would imply that spectral type and/or binarity are important factors in dust grain evolution.

  2. The Influence of Dust on the Absorptivity of Radiant Barriers

    E-Print Network [OSTI]

    Noboa, Homero L.

    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...

  3. Morphological Investigations of Fibrogenic Action of Estonian Oil Shale Dust

    E-Print Network [OSTI]

    V. A. Kung

    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

  4. WEATHER MODIFICATION BY CARBON DUST ABSORPTION OF SOLAR ENERGY

    E-Print Network [OSTI]

    Gray, William

    WEATHER MODIFICATION BY CARBON DUST ABSORPTION OF SOLAR ENERGY by WM. M. GRAY, WM. M. FRANK, M OF SOLAR ENERGY by w. M. Gray, W. M. Frank, M. L. Corrin and C. A. Stokes Department of Atmospheric Science interception of solar energy. Growing population pressures and predicted future global food shortages dictate

  5. DIII-D Dust Particulate Characterization (June 1998 Vent)

    SciTech Connect (OSTI)

    Carmack, William Jonathan

    1999-01-01T23:59:59.000Z

    Dust is a key component of fusion power device accident source term. Understanding the amount of dust expected in fusion power devices and its physical and chemical characteristics is needed to verify assumptions currently used in safety analyses. An important part of this safety research and development work is to characterize dust from existing experimental tokamaks. In this report, we present the collection, data analysis methods used, and the characterization of dust particulate collected from various locations inside the General Atomics DIII-D vacuum vessel following the June 1998 vent. The collected particulate was analyzed at the Idaho National Engineering and Environmental Laboratory (INEEL). Two methods were used to collect particulate with the goal of preserving the particle size distribution and physical characteristics of the particulate. Choice of collection technique is important because the sampling method used can bias the particle size distribution collected. Vacuum collection on substrates and adhesion removal with metallurgical replicating tape were chosen as non-intrusive sampling methods. Seventeen samples were collected including plasma facing surfaces in lower, upper, and horizontal locations, surfaces behind floor tiles, surfaces behind divertor tiles, and surfaces behind ceiling tiles. The results of the analysis are presented.

  6. DIII-D dust particulate characterization (June 1998 Vent)

    SciTech Connect (OSTI)

    Carmack, W.J.

    1999-01-01T23:59:59.000Z

    Dust is a key component of fusion power device accident source term. Understanding the amount of dust expected in fusion power devices and its physical and chemical characteristics is needed to verify assumptions currently used in safety analyses. An important part of this safety research and development work is to characterize dust from existing experimental tokamaks. In this report, the authors present the collection, data analysis methods used, and the characterization of dust particulate collected from various locations inside the General Atomics DIII-D vacuum vessel following the June 1998 vent. The collected particulate was analyzed at the Idaho National Engineering and Environmental Laboratory (INEEL). Two methods were used to collect particulate with the goal of preserving the particle size distribution and physical characteristics of the particulate. Choice of collection technique is important because the sampling method used can bias the particle size distribution collected. Vacuum collection on substrates and adhesion removal with metallurgical replicating tape were chosen as non-intrusive sampling methods. Seventeen samples were collected including plasma facing surfaces in lower, upper, and horizontal locations, surfaces behind floor tiles, surfaces behind divert or tiles, and surfaces behind ceiling tiles. The results of the analysis are presented.

  7. Magnetic field modulated dust streams from Jupiter in Interplanetary space

    E-Print Network [OSTI]

    Hamilton, Douglas P.

    Magnetic field modulated dust streams from Jupiter in Interplanetary space Alberto Flandes Ciencias´es-Galicia Ciencias Espaciales, Instituto de Geof´isica, UNAM, M´exico. Linda Spilker Jet Propulsion Laboratory is sufficient to allow the planet's magnetic field to accelerate them away from the planet where

  8. absorption features dust: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    absorption features dust First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Silicon carbide absorption...

  9. Particulate matter dynamics

    E-Print Network [OSTI]

    Cionco, Rodolfo G; Caligaris, Marta G

    2012-01-01T23:59:59.000Z

    A substantial fraction of the particulate matter released into the atmosphere by industrial or natural processes corresponds to particles whose aerodynamic diameters are greater than 50 mm. It has been shown that, for these particles, the classical description of Gaussian plume diffusion processes, is inadequate to describe the transport and deposition. In this paper we present new results concerning the dispersion of coarse particulate matter. The simulations are done with our own code that uses the Bulirsch Stoer numerical integrator to calculate threedimensional trajectories of particles released into the environment under very general conditions. Turbulent processes are simulated by the Langevin equation and weather conditions are modeled after stable (Monin-Obukhov length L> 0) and unstable conditions (L <0). We present several case studies based on Monte Carlo simulations and discusses the effect of weather on the final deposition of these particles.

  10. Constraining Decaying Dark Matter

    E-Print Network [OSTI]

    Ran Huo

    2011-07-13T23:59:59.000Z

    We revisited the decaying dark matter (DDM) model, in which one collisionless particle decays early into two collisionless particles, that are potentially dark matter particles today. The effect of DDM will be manifested in the cosmic microwave background (CMB) and structure formation. With a systematic modification of CMB calculation tool \\texttt{camb}, we can numerically calculated this effect, and compare it to observations. Further Markov Chain Monte Carlo \\texttt{cosmomc} runnings update the constraints in that model: the free streaming length $\\lambda_{FS}\\lesssim0.5$Mpc for nonrelativistic decay, and $((M_{DDM}/keV) Y)^2 (T_d/yr)\\lesssim5\\times10^{-5}$ for relativistic decay.

  11. Dark matter particles

    E-Print Network [OSTI]

    V. Berezinsky

    1996-10-31T23:59:59.000Z

    The baryonic and cold dark matter are reviewed in the context of cosmological models. The theoretical search for the particle candidates is limited by supersymmetric extension of the Standard Model. Generically in such models there are just two candidates associated with each other: generalized neutralino, which components are usual neutralino and axino, and axion which is a partner of axino in supermultiplet. The status of these particles as DM candidates is described.

  12. INTERSTELLAR SILICATE DUST IN THE z = 0.89 ABSORBER TOWARD PKS 1830-211: CRYSTALLINE SILICATES AT HIGH REDSHIFT?

    SciTech Connect (OSTI)

    Aller, Monique C.; Kulkarni, Varsha P.; Som, Debopam [Department of Physics and Astronomy, University of South Carolina, 712 Main Street, Columbia, SC 29208 (United States); York, Donald G.; Welty, Daniel E. [Department of Astronomy and Astrophysics, University of Chicago, 5640 S. Ellis Ave., Chicago, IL 60637 (United States); Vladilo, Giovanni, E-mail: ALLERM@mailbox.sc.edu [Osservatorio Astonomico di Trieste, Via Tiepolo 11, 34143 Trieste (Italy)

    2012-03-20T23:59:59.000Z

    We present evidence of a >10{sigma} detection of the 10 {mu}m silicate dust absorption feature in the spectrum of the gravitationally lensed quasar PKS 1830-211, produced by a foreground absorption system at redshift 0.886. We have examined more than 100 optical depth templates, derived from both observations of Galactic and extragalactic sources and laboratory measurements, in order to constrain the chemical structure of the silicate dust. We find that the best fit to the observed absorption profile is produced by laboratory crystalline olivine, with a corresponding peak optical depth of {tau}{sub 10} = 0.27 {+-} 0.05. The fit is slightly improved upon by including small contributions from additional materials, such as silica, enstatite, or serpentine, which suggests that the dust composition may consist of a blend of crystalline silicates. Combining templates for amorphous and crystalline silicates, we find that the fraction of crystalline silicates needs to be at least 95%. Given the rarity of extragalactic sources with such a high degree of silicate crystallinity, we also explore the possibility that the observed spectral features are produced by amorphous silicates in combination with other molecular or atomic transitions, or by foreground source contamination. While we cannot rule out these latter possibilities, they lead to much poorer profile fits than for the crystalline olivine templates. If the presence of crystalline interstellar silicates in this distant galaxy is real, it would be highly unusual, given that the Milky Way interstellar matter contains essentially only amorphous silicates. It is possible that the z = 0.886 absorber toward PKS 1830-211, well known for its high molecular content, has a unique star-forming environment that enables crystalline silicates to form and prevail.

  13. Luminous Dark Matter

    E-Print Network [OSTI]

    Brian Feldstein; Peter W. Graham; Surjeet Rajendran

    2011-01-13T23:59:59.000Z

    We propose a dark matter model in which the signal in direct detection experiments arises from electromagnetic, not nuclear, energy deposition. This can provide a novel explanation for DAMA while avoiding many direct detection constraints. The dark matter state is taken nearly degenerate with another state. These states are naturally connected by a dipole moment operator, which can give both the dominant scattering and decay modes between the two states. The signal at DAMA then arises from dark matter scattering in the Earth into the excited state and decaying back to the ground state through emission of a single photon in the detector. This model has unique signatures in direct detection experiments. The density and chemical composition of the detector is irrelevant, only the total volume affects the event rate. In addition, the spectrum is a monoenergetic line, which can fit the DAMA signal well. This model is readily testable at experiments such as CDMS and XENON100 if they analyze their low-energy, electronic recoil events.

  14. Dark matter axions revisited

    SciTech Connect (OSTI)

    Visinelli, Luca; Gondolo, Paolo [Department of Physics, University of Utah, 115 S 1400 E 201, Salt Lake City, Utah 84102 (United States)

    2009-08-01T23:59:59.000Z

    We study for what specific values of the theoretical parameters the axion can form the totality of cold dark matter. We examine the allowed axion parameter region in the light of recent data collected by the WMAP5 mission plus baryon acoustic oscillations and supernovae, and assume an inflationary scenario and standard cosmology. We also upgrade the treatment of anharmonicities in the axion potential, which we find important in certain cases. If the Peccei-Quinn symmetry is restored after inflation, we recover the usual relation between axion mass and density, so that an axion mass m{sub a}=(85{+-}3) {mu}eV makes the axion 100% of the cold dark matter. If the Peccei-Quinn symmetry is broken during inflation, the axion can instead be 100% of the cold dark matter for m{sub a}<15 meV provided a specific value of the initial misalignment angle {theta}{sub i} is chosen in correspondence to a given value of its mass m{sub a}. Large values of the Peccei-Quinn symmetry breaking scale correspond to small, perhaps uncomfortably small, values of the initial misalignment angle {theta}{sub i}.

  15. Hidden vector dark matter

    E-Print Network [OSTI]

    Thomas Hambye

    2010-03-16T23:59:59.000Z

    We show that dark matter could be made of massive gauge bosons whose stability doesn't require to impose by hand any discrete or global symmetry. Stability of gauge bosons can be guaranteed by the custodial symmetry associated to the gauge symmetry and particle content of the model. The particle content we consider to this end is based on a hidden sector made of a vector multiplet associated to a non-abelian gauge group and of a scalar multiplet charged under this gauge group. The hidden sector interacts with the Standard Model particles through the Higgs portal quartic scalar interaction in such a way that the gauge bosons behave as thermal WIMPS. This can lead easily to the observed dark matter relic density in agreement with the other various constraints, and can be tested experimentally in a large fraction of the parameter space. In this model the dark matter direct detection rate and the annihilation cross section can decouple if the Higgs portal interaction is weak.

  16. H_2D^+: a light on baryonic dark matter?

    E-Print Network [OSTI]

    Cecilia Ceccarelli; Carsten Dominik

    2006-02-27T23:59:59.000Z

    It has been suggested that the dark halos of galaxies are constituted by cloudlets of cold ( 10^7$ cm^{-3}) molecular gas. Such gas is extremely difficult to detect, because the classical tracers of molecular gas, CO and/or dust grains, have very low abundances and their emission is exceedingly weak. For this reason, the cloudlet hypothesis remains so far substantially unproven. In this Letter we propose a new method to probe the presence of cold H_2 clouds in galactic halos: the ground transition of ortho-H_2D^+ at 372 GHz. We discuss why the H_2D^+ is abundant under the physical conditions appropriate for the cloudlets, and present a chemical model that predicts the H_2D^+ abundance as function of four key parameters: gas density and metallicity, cosmic ray ionization rate and dust grain size. We conclude that current ground-based instruments might detect the ortho-H_2D^+ line emitted by the cloudlets halo, and prove, therefore, the existence of large quantities of dark baryonic matter around galaxies.

  17. A NEW VIEW ON INTERSTELLAR DUST HIGH FIDELITY STUDIES OF INTERSTELLAR DUST ANALOGUE TRACKS IN STARDUST FLIGHT SPARE AEROGEL

    E-Print Network [OSTI]

    IN STARDUST FLIGHT SPARE AEROGEL F. Postberg, C. Allen, S. Bajt, H. A. Bechtel, J. Borg, F. Brenker, J the Stardust Mission exposed aerogel collector panels for a total of about 200 days to the stream - 30km/s] interstellar dust (ISD) analogues onto Stardust aerogel flight spares. This en- ables

  18. Cadmium, lead and mercury exposure in non smoking pregnant women

    SciTech Connect (OSTI)

    Hinwood, A.L., E-mail: a.hinwood@ecu.edu.au [Centre for Ecosystem Management, Edith Cowan University, 270 Joondalup Drive, Joondalup, WA 6027 (Australia); Callan, A.C.; Ramalingam, M.; Boyce, M. [Centre for Ecosystem Management, Edith Cowan University, 270 Joondalup Drive, Joondalup, WA 6027 (Australia)] [Centre for Ecosystem Management, Edith Cowan University, 270 Joondalup Drive, Joondalup, WA 6027 (Australia); Heyworth, J. [School Population Health, The University of Western Australia, 35 Stirling Highway Crawley, WA 6009 (Australia)] [School Population Health, The University of Western Australia, 35 Stirling Highway Crawley, WA 6009 (Australia); McCafferty, P. [ChemCentre, PO Box 1250, Bentley, WA 6983 (Australia)] [ChemCentre, PO Box 1250, Bentley, WA 6983 (Australia); Odland, J.Ø. [Department of Community Medicine, University of Tromsø, N-9037 Tromsø (Norway)] [Department of Community Medicine, University of Tromsø, N-9037 Tromsø (Norway)

    2013-10-15T23:59:59.000Z

    Recent literature suggests that exposure to low concentrations of heavy metals may affect both maternal and child health. This study aimed to determine the biological heavy metals concentrations of pregnant women as well as environmental and dietary factors that may influence exposure concentrations. One hundred and seventy three pregnant women were recruited from Western Australia, each providing a sample of blood, first morning void urine, residential soil, dust and drinking water samples. Participants also completed a questionnaire which included a food frequency component. All biological and environmental samples were analysed for heavy metals using ICP-MS. Biological and environmental concentrations of lead and mercury were generally low (Median Pb Drinking Water (DW) 0.04 µg/L; Pb soil <3.0 µg/g; Pb dust 16.5 µg/g; Pb blood 3.67 µg/L; Pb urine 0.55; µg/L Hg DW <0.03; Hg soil <1.0 µg/g; Hg dust <1.0 µg/g; Hg blood 0.46 µg/L; Hg urine <0.40 µg/L). Cadmium concentrations were low in environmental samples (Median CdDW 0.02 µg/L; Cdsoil <0.30 ug/g; Cddust <0.30) but elevated in urine samples (Median 0.55 µg/L, creatinine corrected 0.70 µg/g (range <0.2–7.06 µg/g creatinine) compared with other studies of pregnant women. Predictors of increased biological metals concentrations in regression models for blood cadmium were residing in the Great Southern region of Western Australia and not using iron/folic acid supplements and for urinary cadmium was having lower household annual income. However, these factors explained little of the variation in respective biological metals concentrations. The importance of establishing factors that influence low human exposure concentrations is becoming critical in efforts to reduce exposures and hence the potential for adverse health effects. -- Highlights: • Biological heavy metals concentrations in women in their 3rd trimester of pregnancy. • Exposure assessment including environmental, lifestyle and activity data. • Urinary cadmium concentrations were elevated in this group of pregnant women. • Blood lead and mercury concentrations were below recommended biological guideline values.

  19. Dust acoustic solitary and shock excitations in a Thomas-Fermi magnetoplasma

    SciTech Connect (OSTI)

    Rahim, Z.; Qamar, A. [Institute of Physics and Electronics, University of Peshawar, Peshawar 25000 (Pakistan); National Center for Physics (NCP) at QAU Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Ali, S. [National Center for Physics (NCP) at QAU Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan)

    2014-07-15T23:59:59.000Z

    The linear and nonlinear properties of dust-acoustic waves are investigated in a collisionless Thomas-Fermi magnetoplasma, whose constituents are electrons, ions, and negatively charged dust particles. At dust time scale, the electron and ion number densities follow the Thomas-Fermi distribution, whereas the dust component is described by the classical fluid equations. A linear dispersion relation is analyzed to show that the wave frequencies associated with the upper and lower modes are enhanced with the variation of dust concentration. The effect of the latter is seen more strongly on the upper mode as compared to the lower mode. For nonlinear analysis, we obtain magnetized Korteweg-de Vries (KdV) and Zakharov-Kuznetsov (ZK) equations involving the dust-acoustic solitary waves in the framework of reductive perturbation technique. Furthermore, the shock wave excitations are also studied by allowing dissipation effects in the model, leading to the Korteweg-de Vries-Burgers (KdVB) and ZKB equations. The analysis reveals that the dust-acoustic solitary and shock excitations in a Thomas-Fermi plasma are strongly influenced by the plasma parameters, e.g., dust concentration, dust temperature, obliqueness, magnetic field strength, and dust fluid viscosity. The present results should be important for understanding the solitary and shock excitations in the environments of white dwarfs or supernova, where dust particles can exist.

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

    DOE Patents [OSTI]

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

    1988-01-01T23:59:59.000Z

    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.

  1. Dust-acoustic waves in nonuniform dusty plasma in presence of polarization force

    SciTech Connect (OSTI)

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

    2011-11-15T23:59:59.000Z

    The effects of the dust density nonuniformity and the polarization force on linear propagation of the dust-acoustic waves in a nonuniform dusty plasma (consisting of electrons, ions, and arbitrarily charged dust particles) have been theoretically investigated. It has been shown that the linear dispersion properties of the dust-acoustic (DA) waves have been significantly modified by the dust density nonuniformity, dust polarity, and the polarization force. It is also found here that the phase speed of the DA waves is decreased by the effects of polarization force, and that their amplitude increases with the decrease of equilibrium dust number density. The different situations, which are relevant to different space and laboratory dusty plasmas, have been briefly discussed.

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

    SciTech Connect (OSTI)

    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

    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.

  3. Consequences of three-dimensional physical and electromagnetic structures on dust particle trapping in high plasma density

    E-Print Network [OSTI]

    Kushner, Mark

    gradients are present, which introduce fluid drag and thermophoretic forces, dust particle traps may

  4. Molecular and atomic gas in dust lane early-type galaxies - I: Low star-formation efficiencies in minor merger remnants

    E-Print Network [OSTI]

    Davis, Timothy A; Allison, James R; Shabala, Stanislav S; Ting, Yuan-Sen; Lagos, Claudia del P; Kaviraj, Sugata; Bourne, Nathan; Dunne, Loretta; Eales, Steve; Ivison, Rob J; Maddox, Steve; Smith, Daniel J B; Smith, Matthew W L; Temi, Pasquale

    2015-01-01T23:59:59.000Z

    In this work we present IRAM-30m telescope observations of a sample of bulge-dominated galaxies with large dust lanes, which have had a recent minor merger. We find these galaxies are very gas rich, with H2 masses between 4x10^8 and 2x10^10 Msun. We use these molecular gas masses, combined with atomic gas masses from an accompanying paper, to calculate gas-to-dust and gas-to-stellar mass ratios. The gas-to-dust ratios of our sample objects vary widely (between ~50 and 750), suggesting many objects have low gas-phase metallicities, and thus that the gas has been accreted through a recent merger with a lower mass companion. We calculate the implied minor companion masses and gas fractions, finding a median predicted stellar mass ratio of ~40:1. The minor companion likely had masses between ~10^7 - 10^10 Msun. The implied merger mass ratios are consistent with the expectation for low redshift gas-rich mergers from simulations. We then go on to present evidence that (no matter which star-formation rate indicator ...

  5. Smoke-free Movies from Evidence to Action 2nd Edition

    E-Print Network [OSTI]

    WHO

    2011-01-01T23:59:59.000Z

    guidelines recommend that: Parties should take particular measuresmeasures included in the WHO FCTC Article 13 guidelines,Measures to limit movie smoking, including those outlined in the Article 13 guidelines,

  6. Arsenic exposure, smoking, and lung cancer in smelter workers--a case-control study

    SciTech Connect (OSTI)

    Jaerup, L.P.; Pershagen, G. (Department of Environmental Hygiene, Karolinska Institutet, Stockholm (Sweden))

    1991-09-15T23:59:59.000Z

    A cohort of 3,916 Swedish copper smelter workers employed for at least 3 months between 1928 and 1967 was followed up through 1981. Arsenic exposure was estimated for different time periods at each workplace within the smelter. Detailed job records were linked to the exposure matrix, thus forming individual cumulative arsenic exposure measures for each smelter worker. Smoking history was collected for 107 lung cancer cases and 214 controls from the cohort. Lung cancer risks were positively related to cumulative arsenic exposure with smoking standardized relative risks ranging from 0.7 to 8.7 in different exposure groups. A negative confounding by smoking was suggested in the higher exposure categories. The interaction between arsenic and smoking for the risk of developing lung cancer was intermediate between additive and multiplicative and appeared less pronounced among heavy smokers.

  7. Modelling of mineral dust for interglacial and glacial climate conditions with a focus on Antarctica

    SciTech Connect (OSTI)

    Sudarchikova, Natalia; Mikolajewicz, Uwe; Timmreck, C.; O'Donnell, D.; Schurgers, G.; Sein, Dmitry; Zhang, Kai

    2015-01-01T23:59:59.000Z

    Mineral dust cycle responds to insolation-induced climate change and plays an important role in the climate system by affecting the radiative balance of the atmosphere. Polar ice cores provide unique information about deposition of aeolian dust particles in the past which indicates climate variability. In the current study the dust cycle in different climate conditions simulated by ECHAM5-HAM is analyzed. The study is focused on the Southern Hemisphere with emphasis on the Antarctic region. The investigated periods include four interglacial time-slices: the pre-industrial control (CTRL), mid-Holocene (6,000 years BP), Eemian (126,000 years BP), last glacial inception (115,000 years BP) and one glacial time interval: Last Glacial Maximum (LGM) (21,000 years BP). This study is a first attempt to simulate past interglacial dust cycles and to understand the quantitative contribution of different processes, such as emission, atmospheric transport and precipitation to the total dust deposition in Antarctica. Results suggest increased deposition of mineral dust globally and in Antarctica in the past interglacial periods relative to the preindustrial CTRL simulation. Maximum dust deposition in Antarctica was simulated for the glacial period. One of the major factors responsible for the increase of dust deposition in the mid-Holocene and Eemian is enhanced Southern Hemisphere dust emissions. The moderate change of dust deposition in Antarctica in the last glacial inception period is caused by the slightly stronger poleward atmospheric transport efficiency compared to the pre-industrial. In the LGM simulation, dust deposition over Antarctica is substantially increased due to 2.6 times higher Southern Hemisphere dust emissions, 2 times stronger atmospheric transport towards Antarctica, and 30% weaker precipitation over the Southern Ocean. The model is able to reproduce the order of magnitude of dust deposition globally and in Antarctica for the pre-industrial and LGM climate. However more records are needed to validate simulated dust deposition for the past interglacial time-slices.

  8. DUST EMISSION AND STAR FORMATION IN STEPHAN'S QUINTET

    SciTech Connect (OSTI)

    Natale, G.; Tuffs, R. J. [Max Planck Institute fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Xu, C. K.; Lu, N. [Infrared Processing and Analysis Center, California Institute of Technology 100-22, Pasadena, CA 91125 (United States); Popescu, C. C. [University of Central Lancashire, Preston, PR1 2HE (United Kingdom); Fischera, J. [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 Saint George Street, Toronto, ON, M5S 3H8 (Canada); Lisenfeld, U. [Department de Fisica Teorica y del Cosmos, Universidad de Granada, Granada (Spain); Appleton, P. [NASA Herschel Science Center, IPAC, California Institute of Technology, Pasadena, CA 91125 (United States); Dopita, M. [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Duc, P.-A. [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, Dapnia/Service d'Astrophysique, CEA-Saclay, 91191 Gif-sur-Yvette Cedex (France); Gao, Y. [Purple Mountain Observatory, Chinese Academy of Sciences, 2 West Beijing Road, Nanjing 210008 (China); Reach, W. [Spitzer Science Center, IPAC, California Institute of Technology, Pasadena, CA 91125 (United States); Sulentic, J. [Instituto de Astrofisica de AndalucIa, CSIC, Apdo. 3004, 18080, Granada (Spain); Yun, M., E-mail: giovanni.natale@mpi-hd.mpg.d, E-mail: richard.buffs@mpi-hd.mpg.d [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)

    2010-12-10T23:59:59.000Z

    We analyze a comprehensive set of MIR/FIR observations of Stephan's Quintet (SQ), taken with the Spitzer Space Telescope. Our study reveals the presence of a luminous (L{sub IR} {approx} 4.6 x 10{sup 43} erg s{sup -1}) and extended component of infrared dust emission, not connected with the main bodies of the galaxies, but roughly coincident with the X-ray halo of the group. We fitted the inferred dust emission spectral energy distribution of this extended source and the other main infrared emission components of SQ, including the intergalactic shock, to elucidate the mechanisms powering the dust and polycyclic aromatic hydrocarbon emission, taking into account collisional heating by the plasma and heating through UV and optical photons. Combining the inferred direct and dust-processed UV emission to estimate the star formation rate (SFR) for each source we obtain a total SFR for SQ of 7.5 M{sub sun} yr{sup -1}, similar to that expected for non-interacting galaxies with stellar mass comparable to the SQ galaxies. Although star formation in SQ is mainly occurring at, or external to the periphery of the galaxies, the relation of SFR per unit physical area to gas column density for the brightest sources is similar to that seen for star formation regions in galactic disks. We also show that available sources of dust in the group halo can provide enough dust to produce up to L{sub IR} {approx} 10{sup 42} erg s{sup -1} powered by collisional heating. Though a minority of the total infrared emission (which we infer to trace distributed star-formation), this is several times higher than the X-ray luminosity of the halo, so could indicate an important cooling mechanism for the hot intergalactic medium (IGM) and account for the overall correspondence between FIR and X-ray emission. We investigate two potential modes of star formation in SQ consistent with the data, fueled either by gas from a virialized hot IGM continuously accreting onto the group, whose cooling is enhanced by grains injected from an in situ population of intermediate mass stars, or by interstellar gas stripped from the galaxies. The former mode offers a natural explanation for the observed baryon deficiency in the IGM of SQ as well as for the steep L{sub X}-T{sub X} relation of groups such as SQ with lower velocity dispersions.

  9. Superconnections and Matter

    E-Print Network [OSTI]

    Roepstorff, G

    1998-01-01T23:59:59.000Z

    In a previous paper, the superconnection formalism was used to naturally fit the Higgs field into a U(n) gauge theory where we aimed at the reconstruction of the standard model. The approach provides an alternative to non-commutative geometry. This work is now continued by including matter field (leptons). The essentially new ingredient is the right-handed neutrino field and a new kind of interaction that goes with it. All interactions follow from one Dirac operator associated to a superconnection.

  10. Superconnections and Matter

    E-Print Network [OSTI]

    G. Roepstorff

    2000-08-17T23:59:59.000Z

    In a previous paper (hep-th/9801040), the superconnection formalism was used to fit the Higgs field into a U(n) gauge theory with particular emphasis on the n=2 case, aiming at the reconstruction of certain parts of the Standard Model. The approach provides an alternative to the one bases on non-commutative geometry. This work is continued by including matter fields (leptons only). We extend the Standard Model by including the right-handed neutrino field. The possibility of a finite neutrino mass is thus accounted for.

  11. Thermodynamics of electroweak matter

    E-Print Network [OSTI]

    A. Gynther

    2006-09-21T23:59:59.000Z

    This paper is a slightly modified version of the introductory part of a PhD thesis, also containing the articles hep-ph/0303019, hep-ph/0510375 and hep-ph/0512177. We provide a short history of the research of electroweak thermodynamics and a brief introduction to the theory as well as to the necessary theoretical tools needed to work at finite temperatures. We then review computations regarding the pressure of electroweak matter at high temperatures (the full expression of the perturbative expansion of the pressure is given in the appendix) and the electroweak phase diagram at finite chemical potentials. Finally, we compare electroweak and QCD thermodynamics.

  12. Discrete dark matter

    SciTech Connect (OSTI)

    Hirsch, M.; Morisi, S.; Peinado, E.; Valle, J. W. F. [AHEP Group, Institut de Fisica Corpuscular--C.S.I.C./Universitat de Valencia, Edificio Institutos de Paterna, Apartado 22085, E-46071 Valencia (Spain)

    2010-12-01T23:59:59.000Z

    We propose a new motivation for the stability of dark matter (DM). We suggest that the same non-Abelian discrete flavor symmetry which accounts for the observed pattern of neutrino oscillations, spontaneously breaks to a Z{sub 2} subgroup which renders DM stable. The simplest scheme leads to a scalar doublet DM potentially detectable in nuclear recoil experiments, inverse neutrino mass hierarchy, hence a neutrinoless double beta decay rate accessible to upcoming searches, while {theta}{sub 13}=0 gives no CP violation in neutrino oscillations.

  13. Particulate Matter Aerosols

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItemResearch > TheNuclear Astrophysics OneOutreach EffortsSearchParticulate Matter

  14. Dark Matter Theory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power Administration wouldDECOMPOSITION OFSupplemental TechnologySummaryDariuszDark Matter Theory

  15. THE IMPORTANCE OF PHYSICAL MODELS FOR DERIVING DUST MASSES AND GRAIN SIZE DISTRIBUTIONS IN SUPERNOVA EJECTA. I. RADIATIVELY HEATED DUST IN THE CRAB NEBULA

    SciTech Connect (OSTI)

    Temim, Tea; Dwek, Eli, E-mail: tea.temim@nasa.gov [Observational Cosmology Lab, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2013-09-01T23:59:59.000Z

    Recent far-infrared (IR) observations of supernova remnants (SNRs) have revealed significantly large amounts of newly condensed dust in their ejecta, comparable to the total mass of available refractory elements. The dust masses derived from these observations assume that all the grains of a given species radiate at the same temperature, regardless of the dust heating mechanism or grain radius. In this paper, we derive the dust mass in the ejecta of the Crab Nebula, using a physical model for the heating and radiation from the dust. We adopt a power-law distribution of grain sizes and two different dust compositions (silicates and amorphous carbon), and calculate the heating rate of each dust grain by the radiation from the pulsar wind nebula. We find that the grains attain a continuous range of temperatures, depending on their size and composition. The total mass derived from the best-fit models to the observed IR spectrum is 0.019-0.13 M{sub Sun }, depending on the assumed grain composition. We find that the power-law size distribution of dust grains is characterized by a power-law index of 3.5-4.0 and a maximum grain size larger than 0.1 {mu}m. The grain sizes and composition are consistent with what is expected for dust grains formed in a Type IIP supernova (SN). Our derived dust mass is at least a factor of two less than the mass reported in previous studies of the Crab Nebula that assumed more simplified two-temperature models. These models also require a larger mass of refractory elements to be locked up in dust than was likely available in the ejecta. The results of this study show that a physical model resulting in a realistic distribution of dust temperatures can constrain the dust properties and affect the derived dust masses. Our study may also have important implications for deriving grain properties and mass estimates in other SNRs and for the ultimate question of whether SNe are major sources of dust in the Galactic interstellar medium and in external galaxies.

  16. Smoke emissions from prescribed burning of southern California Chaparral. Forest Service research paper

    SciTech Connect (OSTI)

    Hardy, C.C.; Conard, S.G.; Regelbrugge, J.C.; Teesdale, D.R.

    1995-11-01T23:59:59.000Z

    This report describes a comprehensive study characterizing the smoke emissions from small scale prescribed burns in southern California chaparral. In situ measurements of smoke emissions were made from 12 fires. Three replicate tests were performed in each of four distinct fuel and treatment types. Emission factors for each treatment are presented and also are combined with data from previous tests for general application to fires in standing chaparral.

  17. Progress in developing the smoke source term for ''nuclear winter'' studies: major uncertainties

    SciTech Connect (OSTI)

    Penner, J.E.

    1986-03-01T23:59:59.000Z

    The potential effects on climate of large amounts of smoke injected into the atmosphere following a major nuclear exchange have been widely analyzed (Crutzen and Birks, 1982; Turco et al., 1983, NRC, 1985; Pittock et al., 1986). Although simplifications and uncertainties still exist in the application of climate models to calculate the effects of smoke, many of the simplications that were necessarily made in the first studies have now been corrected. These improved climate models have shown that the effects of smoke on climate depend on the quantity and optical properties of the smoke that is generated and dispersed into the global atmosphere. The smoke amount and its optical properties can be summarized by the average optical depth that would result if the smoke were dispersed throughout half the northern hemisphere. In this paper a range of values for this average optical depth is determined, consistent with recent analyses. Different estimates for each of a variety of contributing factors give rise to a wide range of average optical depths, encompassing values that imply comparatively minor effects on climate to values that imply massive effects. Suggestions for further research that might narrow the range of possibilities are made.

  18. Spherically symmetric cosmological spacetimes with dust and radiation — numerical implementation

    SciTech Connect (OSTI)

    Lim, Woei Chet [Department of Mathematics, University of Waikato, Private Bag 3105, Hamilton 3240 (New Zealand); Regis, Marco [Dipartimento di Fisica, Università di Torino and INFN, Torino (Italy); Clarkson, Chris, E-mail: wclim@waikato.ac.nz, E-mail: regis@to.infn.it, E-mail: chris.clarkson@gmail.com [Astrophysics, Cosmology and Gravity Centre, and Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch 7701, Cape Town (South Africa)

    2013-10-01T23:59:59.000Z

    We present new numerical cosmological solutions of the Einstein Field Equations. The spacetime is spherically symmetric with a source of dust and radiation approximated as a perfect fluid. The dust and radiation are necessarily non-comoving due to the inhomogeneity of the spacetime. Such a model can be used to investigate non-linear general relativistic effects present during decoupling or big-bang nucleosynthesis, as well as for investigating void models of dark energy with isocurvature degrees of freedom. We describe the full evolution of the spacetime as well as the redshift and luminosity distance for a central observer. After demonstrating accuracy of the code, we consider a few example models, and demonstrate the sensitivity of the late time model to the degree of inhomogeneity of the initial radiation contrast.

  19. Color-based tracking of plasma dust particles

    SciTech Connect (OSTI)

    Villamayor, Michelle Marie S., E-mail: mvillamayor@nip.upd.edu.ph; Soriano, Maricor N.; Ramos, Henry J. [National Institute of Physics, University of the Philippines, Diliman, Quezon City 1101 (Philippines)] [National Institute of Physics, University of the Philippines, Diliman, Quezon City 1101 (Philippines); Kato, Shuichi; Wada, Motoi [Graduate School of Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)] [Graduate School of Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)

    2014-02-15T23:59:59.000Z

    Color-based tracking to observe agglomeration of deposited particles inside a compact planar magnetron during plasma discharge was done by creating high dynamic range (HDR) images of photos captured by a Pentax K10D digital camera. Carbon erosion and redeposition was also monitored using the technique. The HDR images were subjected to a chromaticity-based constraint discoloration inside the plasma chamber indicating film formation or carbon redeposition. Results show that dust deposition occurs first near the evacuation pumps due to the pressure gradient and then accumulates at the positively charged walls of the chamber. This method can be applied to monitor dust formation during dusty plasma experiments without major modification of plasma devices, useful especially for large fusion reactors.

  20. Spectroscopic diagnostic for the mineralogy of large dust grains

    E-Print Network [OSTI]

    M. Min; C. Dominik; L. B. F. M. Waters

    2003-10-30T23:59:59.000Z

    We examine the thermal infrared spectra of large dust grains of different chemical composition and mineralogy. Strong resonances in the optical properties result in detectable spectral structure even when the grain is much larger than the wavelength at which it radiates. We apply this to the thermal infrared spectra of compact amorphous and crystalline silicates. The weak resonances of amorphous silicates at 9.7 and 18 micron virtually disappear for grains larger than about 10 micron. In contrast, the strong resonances of crystalline silicates produce emission dips in the infrared spectra of large grains; these emission dips are shifted in wavelength compared to the emission peaks commonly seen in small crystalline silicate grains. We discuss the effect of a fluffy or compact grain structure on the infrared emission spectra of large grains, and apply our theory to the dust shell surrounding Vega.

  1. Effect of dust models on global nuclear winter. Master's thesis

    SciTech Connect (OSTI)

    Pontier, P.Q.

    1986-03-01T23:59:59.000Z

    A series of optical-depth calculations were accomplished to assess the effects of various existing dust and soot models on the transmission of incident sunlight. A change in the standard deviation of the particle-size distribution from two to four, assuming constant total density, resulted in a decrease in the visible optical depth by a factor of ten. A technique using a method of direct integration was developed for the calculation of the effective optical depth of nuclear-induced dust and soot clouds. Contributions from directly transmitted photons, first scattered photons using anisotropic cross sections, and all subsequently scattered photons were used to calculate the amount of light transmitted through the cloud. Absorption effects were also included. The results of this study were comparable to the results of several recent nuclear winter studies.

  2. Dust trapping by spiral arms in gravitationally unstable protostellar discs

    E-Print Network [OSTI]

    Dipierro, Giovanni; Lodato, Giuseppe; Testi, Leonardo

    2015-01-01T23:59:59.000Z

    In this paper we discuss the influence of gravitational instabilities in massive protostellar discs on the dynamics of dust grains. Starting from a Smoothed Particle Hydrodynamics (SPH) simulation, we have computed the evolution of the dust in a quasi-static gas density structure typical of self-gravitating disc. For different grain size distributions we have investigated the capability of spiral arms to trap particles. We have run 3D radiative transfer simulations in order to construct maps of the expected emission at (sub-)millimetre and near-infrared wavelengths. Finally, we have simulated realistic observations of our disc models at (sub-)millimetre and near-infrared wavelengths as they may appear with the Atacama Large Millimetre/sub-millimetre Array (ALMA) and the High-Contrast Coronographic Imager for Adaptive Optics (HiCIAO) in order to investigate whether there are observational signatures of the spiral structure. We find that the pressure inhomogeites induced by gravitational instabilities produce a...

  3. Development of a GIS Based Dust Dispersion Modeling System.

    SciTech Connect (OSTI)

    Rutz, Frederick C.; Hoopes, Bonnie L.; Crandall, Duard W.; Allwine, K Jerry

    2004-08-12T23:59:59.000Z

    With residential areas moving closer to military training sites, the effects upon the environment and neighboring civilians due to dust generated by training exercises has become a growing concern. Under a project supported by the Strategic Environmental Research and Development Program (SERDP) of the Department of Defense, a custom application named DUSTRAN is currently under development that integrates a system of EPA atmospheric dispersion models with the ArcGIS application environment in order to simulate the dust dispersion generated by a planned training maneuver. This integration between modeling system and GIS application allows for the use of real world geospatial data such as terrain, land-use, and domain size as input by the modeling system. Output generated by the modeling system, such as concentration and deposition plumes, can then be displayed upon accurate maps representing the training site. This paper discusses the development of this integration between modeling system and Arc GIS application.

  4. Nuclear Matter and Nuclear Dynamics

    E-Print Network [OSTI]

    M Colonna

    2009-02-26T23:59:59.000Z

    Highlights on the recent research activity, carried out by the Italian Community involved in the "Nuclear Matter and Nuclear Dynamics" field, will be presented.

  5. Dust production 680-850 million years after the Big Bang

    E-Print Network [OSTI]

    Micha?owski, Micha? J

    2015-01-01T23:59:59.000Z

    Dust plays an important role in our understanding of the Universe, but it is not obvious yet how the dust in the distant universe was formed. I derived the dust yields per asymptotic giant branch (AGB) star and per supernova (SN) required to explain dust masses of galaxies at z = 6.3-7.5 (680-850 million years after the Big Bang) for which dust emission has been detected (HFLS3 at z = 6.34, ULAS J1120+0641 at z = 7.085, and A1689-zD1 at z = 7.5), or unsuccessfully searched for. I found very high required yields, implying that AGB stars could not contribute substantially to dust production at these redshifts, and that SNe could explain these dust masses, but only if they do not destroy majority of the dust they form (which is unlikely given the upper limits on the SN dust yields derived for dust non-detected galaxies). This suggests that the grain growth in the interstellar medium is likely required at these early epochs.

  6. Dust Masses, PAH Abundances, and Starlight Intensities in the SINGS Galaxy Sample

    E-Print Network [OSTI]

    B. T. Draine; D. A. Dale; G. Bendo; K. D. Gordon; J. D. T. Smith; L. Armus; C. W. Engelbracht; G. Helou; R. C. Kennicutt; A. Li; H. Roussel; F. Walter; D. Calzetti; J. Moustakas; E. J. Murphy; G. H. Rieke; C. Bot; D. J. Hollenbach; K. Sheth; H. I. Teplitz

    2007-03-09T23:59:59.000Z

    Physical dust models are presented for 65 galaxies in the SINGS survey that are strongly detected in the four IRAC bands and three MIPS bands. For each galaxy we estimate (1) the total dust mass, (2) the fraction of the dust mass contributed by PAHs, and (3) the intensity of the starlight heating the dust grains. We find that spiral galaxies have dust properties resembling the dust in the local region of the Milky Way, with similar dust-to-gas ratio, and similar PAH abundance. The observed SEDs, including galaxies with SCUBA photometry, can be reproduced by dust models that do not require "cold" (Tmedia of galaxies with A_O=12+log(O/H)>8.1, grains contain a substantial fraction of interstellar Mg, Si and Fe. Galaxies with A_O8.1 have a median q_PAH=3.55%. The derived dust masses favor a value X_CO approx 4e20 cm^{-2}(K kms)^{-1} for the CO to H_2 conversion factor. Except for some starbursting systems (Mrk33, Tolo89, NGC3049), dust in the diffuse ISM dominates the IR power.

  7. Dust Masses, PAH Abundances, and Starlight Intensities in the SINGS Galaxy Sample

    E-Print Network [OSTI]

    Draine, B T; Bendo, G; Gordon, K D; Smith, J D T; Armus, L; Engelbracht, C W; Helou, G; Kennicutt, R C; Li, A; Roussel, H; Walter, F; Calzetti, D; Moustakas, J; Murphy, E J; Rieke, G H; Bot, C; Hollenbach, D J; Sheth, K; Teplitz, H I

    2007-01-01T23:59:59.000Z

    Physical dust models are presented for 65 galaxies in the SINGS survey that are strongly detected in the four IRAC bands and three MIPS bands. For each galaxy we estimate (1) the total dust mass, (2) the fraction of the dust mass contributed by PAHs, and (3) the intensity of the starlight heating the dust grains. We find that spiral galaxies have dust properties resembling the dust in the local region of the Milky Way, with similar dust-to-gas ratio, and similar PAH abundance. The observed SEDs, including galaxies with SCUBA photometry, can be reproduced by dust models that do not require "cold" (T8.1, grains contain a substantial fraction of interstellar Mg, Si and Fe. Galaxies with A_O8.1 have a median q_PAH=3.55%. The derived dust masses favor a value X_CO approx 4e20 cm^{-2}(K kms)^{-1} for the CO to H_2 conversion factor. Except for some starbursting systems (Mrk33, Tolo89, NGC3049), dust in the diffuse ISM dominates the IR power.

  8. Most supermassive black hole growth is obscured by dust

    E-Print Network [OSTI]

    Alejo Martinez-Sansigre; Steve Rawlings; Mark Lacy; Dario Fadda; Francine R. Marleau; Chris Simpson; Chris J. Willott; Matt J. Jarvis

    2005-09-18T23:59:59.000Z

    We present an alternative method to X-ray surveys for hunting down the high-redshift type-2 quasar population, using Spitzer and VLA data on the Spitzer First Look Survey. By demanding objects to be bright at 24 microns but faint at 3.6 microns, and combining this with a radio criterion, we find 21 type-2 radio-quiet quasar candidates at the epoch at which the quasar activity peaked. Optical spectroscopy with the WHT confirmed 10 of these objects to be type-2s with 1.4 < z < 4.2 while the rest are blank. There is no evidence for contamination in our sample, and we postulate that our 11 blank-spectrum candidates are obscured by kpc-scale dust as opposed to dust from a torus around the accretion disk. By carefully modelling our selection criteria, we conclude that, at high redshift, 50-80 % of the supermassive black hole growth is obscured by dust.

  9. The dust, planetesimals and planets of HD 38529

    E-Print Network [OSTI]

    Amaya Moro-Martin; Renu Malhotra; John M. Carpenter; Lynne A. Hillenbrand; Sebastian Wolf; Michael R. Meyer; David Hollenbach; Joan Najita; Thomas Henning

    2007-06-22T23:59:59.000Z

    HD 38529 is a post-main sequence G8III/IV star (3.5 Gyr old) with a planetary system consisting of at least two planets having Msin(i) of 0.8 MJup and 12.2 MJup, semimajor axes of 0.13 AU and 3.74 AU, and eccentricities of 0.25 and 0.35, respectively. Spitzer observations show that HD 38529 has an excess emission above the stellar photosphere, with a signal-to-noise ratio (S/N) at 70 micron of 4.7, a small excess at 33 micron (S/N=2.6) and no excess model the spectral energy distribution of HD 38529 to find out which of these niches show signs of harboring dust-producing plantesimals. The secular analysis, together with the SED modeling resuls, suggest that the planetesimals responsible for most of the dust emission are likely located within 20-50 AU, a configuration that resembles that of the Jovian planets + Kuiper Belt in our Solar System. Finally, we place upper limits (8E-6 lunar masses of 10 micron particles) to the amount of dust that could be located in the dynamically stable region that exists between the two planets (0.25--0.75 AU).

  10. On the Crystallinity of Silicate Dust in the Interstellar Medium

    E-Print Network [OSTI]

    M. P. Li; G. Zhao; Aigen Li

    2008-08-29T23:59:59.000Z

    An accurate knowledge of the mineralogy (chemical composition and crystal structure) of the silicate dust in the interstellar medium (ISM) is crucial for understanding its origin in evolved stars, the physical and chemical processing in the ISM, and its subsequent incorporation into protostellar nebulae, protoplanetary disks and cometary nuclei where it is subjected to further processing. While an appreciable fraction of silicate dust in evolved stars, in protoplanetary disks around pre-main sequence stars, in debris disks around main sequence stars, and in cometary nuclei is found to be in crystalline form, very recent infrared spectroscopic studies of the dust along the sightline toward the Galactic center source Sgr A* placed an upper limit of ~1.1% on the silicate crystalline fraction, well below the previous estimates of ~5% or ~60% derived from the observed 10 micron absorption profile for the local ISM toward Cyg OB2 No.12. Since the sightline toward SgrA contains molecular cloud materials as revealed by the detection of the 3.1 and 6.0 micron water ice absorption features, we argue that by taking into account the presence of ice mantles on silicate cores, the upper limit on the degree of silicate crystallinity in the ISM is increased to ~3--5%.

  11. GRAIN SORTING IN COMETARY DUST FROM THE OUTER SOLAR NEBULA

    SciTech Connect (OSTI)

    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

    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.

  12. Modelling the Deep Counts: Luminosity Evolution, Dust and Faint Galaxies

    E-Print Network [OSTI]

    Ana Campos; Tom Shanks

    1995-11-23T23:59:59.000Z

    In this paper we analyse the deep number counts problem, taking account of new observational and theoretical developments. First we show that the new Bruzual and Charlot (1993) models allow a new class of spiral dominated luminosity evolution (LE) model where significant amounts of the luminosity evolution needed to fit faint count data are due to spiral rather than early-type galaxies. Second we show that the inclusion of dust may be a vital ingredient for obtaining fits with any LE model. Third we compare the quality of fit of both the spiral and early-type LE models, including dust, for a wide variety of observational data. We find that parameters can be found for both LE models which allow a good fit to all data with the exception of the faintest B>25 counts in the case of q0=0.5 cosmologies, where some luminosity dependent evolution may be needed (see also Metcalfe et al 1995). Otherwise both these classes of LE model, with the inclusion of dust, provide an excellent foundation for understanding the B<25 galaxy counts and galaxy counts and redshift distributions in a variety of other wavebands.

  13. Raman Spectroscopy of Carbon Dust Samples from NSTX

    SciTech Connect (OSTI)

    Y. Raitses, C.H. Skinner, F. Jiang and T.S. Duffy

    2008-02-21T23:59:59.000Z

    The Raman spectrum of dust particles exposed to the NSTX plasma is different from the spectrum of unexposed particles scraped from an unused graphite tile. For the unexposed particles, the high energy G-mode peak (Raman shift ~1580 cm-1) is much stronger than the defect-induced D-mode peak (Raman shift ~ 1350 cm-1), a pattern that is consistent with Raman spectrum for commercial graphite materials. For dust particles exposed to the plasma, the ratio of G-mode to D-mode peaks is lower and becomes even less than 1. The Raman measurements indicate that the production of carbon dust particles in NSTX involves modifications of the physical and chemical structure of the original graphite material. These modifications are shown to be similar to those measured for carbon deposits from atmospheric pressure helium arc discharge with an ablating anode electrode made from a graphite tile material. We also demonstrate experimentally that heating to 2000-2700 K alone can not explain the observed structural modifications indicating that they must be due to higher temperatures needed for graphite vaporization, which is followed either by condensation or some plasma-induced processes leading to the formation of more disordered forms of carbon material than the original graphite.

  14. PROPERTIES AND SPATIAL DISTRIBUTION OF DUST EMISSION IN THE CRAB NEBULA

    SciTech Connect (OSTI)

    Temim, Tea; Sonneborn, George; Dwek, Eli; Arendt, Richard G. [Observational Cosmology Lab, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Gehrz, Robert D. [Minnesota Institute for Astrophysics, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States); Slane, Patrick [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Roellig, Thomas L., E-mail: tea.temim@nasa.gov [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035-1000 (United States)

    2012-07-01T23:59:59.000Z

    Recent infrared (IR) observations of freshly formed dust in supernova remnants have yielded significantly lower dust masses than predicted by theoretical models and measured from high-redshift observations. The Crab Nebula's pulsar wind is thought to be sweeping up freshly formed supernova (SN) dust along with the ejected gas. The evidence for this dust was found in the form of an IR excess in the integrated spectrum of the Crab and in extinction against the synchrotron nebula that revealed the presence of dust in the filament cores. We present the first spatially resolved emission spectra of dust in the Crab Nebula acquired with the Infrared Spectrograph on board the Spitzer Space Telescope. The IR spectra are dominated by synchrotron emission and show forbidden line emission from S, Si, Ne, Ar, O, Fe, and Ni. We derived a synchrotron spectral map from the 3.6 and 4.5 {mu}m images, and subtracted this contribution from our data to produce a map of the residual continuum emission from dust. The dust emission appears to be concentrated along the ejecta filaments and is well described by an amorphous carbon or silicate grain compositions. We find a dust temperature of 55 {+-} 4 K for silicates and 60 {+-} 7 K for carbon grains. The total estimated dust mass is (1.2-12) Multiplication-Sign 10{sup -3} M{sub Sun }, well below the theoretical dust yield predicted for a core-collapse supernova. Our grain heating model implies that the dust grain radii are relatively small, unlike what is expected for dust grains formed in a Type IIP SN.

  15. Regional Modeling of Dust Mass Balance and Radiative Forcing over East Asia using WRF-Chem

    SciTech Connect (OSTI)

    Chen, Siyu; Zhao, Chun; Qian, Yun; Leung, Lai-Yung R.; Huang, J.; Huang, Zhongwei; Bi, Jianrong; Zhang, Wu; Shi, Jinsen; Yang, Lei; Li, Deshuai; Li, Jinxin

    2014-12-01T23:59:59.000Z

    The Weather Research and Forecasting model with Chemistry (WRF-Chem) is used to investigate the seasonal and annual variations of mineral dust over East Asia during 2007-2011, with a focus on the dust mass balance and radiative forcing. A variety of measurements from in-stu and satellite observations have been used to evaluate simulation results. Generally, WRF-Chem reproduces not only the column variability but also the vertical profile and size distribution of mineral dust over and near the dust source regions of East Asia. We investigate the dust lifecycle and the factors that control the seasonal and spatial variations of dust mass balance and radiative forcing over the seven sub-regions of East Asia, i.e. source regions, the Tibetan Plateau, Northern China, Southern China, the ocean outflow region, and Korea-Japan regions. Results show that, over the source regions, transport and dry deposition are the two dominant sinks. Transport contributes to ~30% of the dust sink over the source regions. Dust results in a surface cooling of up to -14 and -10 W m-2, atmospheric warming of up to 20 and 15 W m-2, and TOA cooling of -5 and -8 W m-2 over the two major dust source regions of East Asia, respectively. Over the Tibetan Plateau, transport is the dominant source with a peak in summer. Over identified outflow regions, maximum dust mass loading in spring is contributed by the transport. Dry and wet depositions are the comparably dominant sinks, but wet deposition is larger than dry deposition over the Korea-Japan region, particularly in spring (70% versus 30%). The WRF-Chem simulations can generally capture the measured features of dust aerosols and its radaitve properties and dust mass balance over East Asia, which provides confidence for use in further investigation of dust impact on climate over East Asia.

  16. Uncertainty in Modeling Dust Mass Balance and Radiative Forcing from Size Parameterization

    SciTech Connect (OSTI)

    Zhao, Chun; Chen, Siyu; Leung, Lai-Yung R.; Qian, Yun; Kok, Jasper; Zaveri, Rahul A.; Huang, J.

    2013-11-05T23:59:59.000Z

    This study examines the uncertainties in simulating mass balance and radiative forcing of mineral dust due to biases in the aerosol size parameterization. Simulations are conducted quasi-globally (180oW-180oE and 60oS-70oN) using the WRF24 Chem model with three different approaches to represent aerosol size distribution (8-bin, 4-bin, and 3-mode). The biases in the 3-mode or 4-bin approaches against a relatively more accurate 8-bin approach in simulating dust mass balance and radiative forcing are identified. Compared to the 8-bin approach, the 4-bin approach simulates similar but coarser size distributions of dust particles in the atmosphere, while the 3-mode pproach retains more fine dust particles but fewer coarse dust particles due to its prescribed og of each mode. Although the 3-mode approach yields up to 10 days longer dust mass lifetime over the remote oceanic regions than the 8-bin approach, the three size approaches produce similar dust mass lifetime (3.2 days to 3.5 days) on quasi-global average, reflecting that the global dust mass lifetime is mainly determined by the dust mass lifetime near the dust source regions. With the same global dust emission (~6000 Tg yr-1), the 8-bin approach produces a dust mass loading of 39 Tg, while the 4-bin and 3-mode approaches produce 3% (40.2 Tg) and 25% (49.1 Tg) higher dust mass loading, respectively. The difference in dust mass loading between the 8-bin approach and the 4-bin or 3-mode approaches has large spatial variations, with generally smaller relative difference (<10%) near the surface over the dust source regions. The three size approaches also result in significantly different dry and wet deposition fluxes and number concentrations of dust. The difference in dust aerosol optical depth (AOD) (a factor of 3) among the three size approaches is much larger than their difference (25%) in dust mass loading. Compared to the 8-bin approach, the 4-bin approach yields stronger dust absorptivity, while the 3-mode approach yields weaker dust absorptivity. Overall, on quasi-global average, the three size parameterizations result in a significant difference of a factor of 2~3 in dust surface cooling (-1.02~-2.87 W m-2) and atmospheric warming (0.39~0.96 W m-2) and in a tremendous difference of a factor of ~10 in dust TOA cooling (-0.24~-2.20 W m-2). An uncertainty of a factor of 2 is quantified in dust emission estimation due to the different size parameterizations. This study also highlights the uncertainties in modeling dust mass and number loading, deposition fluxes, and radiative forcing resulting from different size parameterizations, and motivates further investigation of the impact of size parameterizations on modeling dust impacts on air quality, climate, and ecosystem.

  17. Charmonium mass in nuclear matter

    E-Print Network [OSTI]

    Lee, S. H.; Ko, Che Ming.

    2003-01-01T23:59:59.000Z

    The mass shift of charmonium states in nuclear matter is studied in the perturbative QCD approach. The leading-order effect due to the change of gluon condensate in nuclear matter is evaluated using the leading-order QCD formula, while the higher...

  18. Astronomical Evidence for Dark Matter

    E-Print Network [OSTI]

    Golwala, Sunil

    weapon in "Quake 4" is the Dark Matter Gun. In Futurama they use dark matter fuel, where "one pound is 10 and neutrons, can compute relative ratio. Using nuclear reaction rates, can compute relative abundances oscillations). Peak is from maximal compression of photon-baryon fluid. Peak sensitive to curvature

  19. Energy Matters in Washington State

    E-Print Network [OSTI]

    Collins, Gary S.

    Energy Matters in Washington State Energy Matters in Washington State www.energy.wsu.edu/library/ November 2009 #12;905 Plum Street SE, Building 3 P.O. Box 43169 Olympia, Washington 98504-3169 Energy University Extension Energy Program. 905 Plum Street SE, Building 3, P.O. Box 43169, Olympia, Washington

  20. A preliminary assessment of beryllium dust oxidation during a wet bypass accident in a fusion reactor

    SciTech Connect (OSTI)

    Brad J. Merrill; Richard L. Moore; J. Phillip Sharp

    2008-09-01T23:59:59.000Z

    A beryllium dust oxidation model has been developed at the Idaho National Laboratory (INL) by the Fusion Safety Program (FSP) for the MELCOR safety computer code. The purpose of this model is to investigate hydrogen production from beryllium dust layers on hot surfaces inside a fusion reactor vacuum vessel (VV) during in-vessel loss-of-cooling accidents (LOCAs). This beryllium dust oxidation model accounts for the diffusion of steam into a beryllium dust layer, the oxidation of the dust particles inside this layer based on the beryllium-steam oxidation equations developed at the INL, and the effective thermal conductivity of this beryllium dust layer. This paper details this oxidation model and presents the results of the application of this model to a wet bypass accident scenario in the ITER device.

  1. Quantum vacuum and dark matter

    E-Print Network [OSTI]

    Dragan Slavkov Hajdukovic

    2011-11-21T23:59:59.000Z

    Recently, the gravitational polarization of the quantum vacuum was proposed as alternative to the dark matter paradigm. In the present paper we consider four benchmark measurements: the universality of the central surface density of galaxy dark matter haloes, the cored dark matter haloes in dwarf spheroidal galaxies, the non-existence of dark disks in spiral galaxies and distribution of dark matter after collision of clusters of galaxies (the Bullet cluster is a famous example). Only some of these phenomena (but not all of them) can (in principle) be explained by the dark matter and the theories of modified gravity. However, we argue that the framework of the gravitational polarization of the quantum vacuum allows the understanding of the totality of these phenomena.

  2. Tropical biomass burning smoke plume size, shape, reflectance, and age based on 2001â??2009 MISR imagery of Borneo

    E-Print Network [OSTI]

    Zender, C. S.; Krolewski, A. G.; Tosca, M. G.; Randerson, J. T.

    2012-01-01T23:59:59.000Z

    C. S. Zender et al. : Tropical biomass burning smoke plumeslaboratory measurements of biomass-burning emis- sions: 1.aerosol optical depth biomass burning events: a comparison

  3. Accretion of dust grains as a possible origin of metal-poor stars with low alpha/Fe ratios

    E-Print Network [OSTI]

    Shigeyama, T; Shigeyama, Toshikazu; Tsujimoto, Takuji

    2003-01-01T23:59:59.000Z

    The origin of low alpha/Fe ratios in some metal-poor stars, so called low-alpha stars, is discussed. It is found that most of low-alpha stars in the Galaxy are on the main-sequence. This strongly suggests that these stars suffered from external pollution. It is also found that the abundance ratios Zn/Fe of low-alpha stars both in the Galaxy and in dwarf spheroidal galaxies are lower than the average value of Galactic halo stars whereas damped Ly alpha absorbers have higher ratios. This implies that some low-alpha stars accreted matter depleted from gas onto dust grains. To explain the features in these low-alpha stars, we have proposed that metal-poor stars harboring planetary systems are the origin of these low-alpha stars. Stars engulfing a small fraction of planetesimals enhance the surface content of Fe to exhibit low alpha/Fe ratios on their surfaces while they are on the main-sequence, because dwarfs have shallow surface convection zones where the engulfed matter is mixed. After the stars leave the main...

  4. Accretion of dust grains as a possible origin of metal-poor stars with low alpha/Fe ratios

    E-Print Network [OSTI]

    Toshikazu Shigeyama; Takuji Tsujimoto

    2003-10-10T23:59:59.000Z

    The origin of low alpha/Fe ratios in some metal-poor stars, so called low-alpha stars, is discussed. It is found that most of low-alpha stars in the Galaxy are on the main-sequence. This strongly suggests that these stars suffered from external pollution. It is also found that the abundance ratios Zn/Fe of low-alpha stars both in the Galaxy and in dwarf spheroidal galaxies are lower than the average value of Galactic halo stars whereas damped Ly alpha absorbers have higher ratios. This implies that some low-alpha stars accreted matter depleted from gas onto dust grains. To explain the features in these low-alpha stars, we have proposed that metal-poor stars harboring planetary systems are the origin of these low-alpha stars. Stars engulfing a small fraction of planetesimals enhance the surface content of Fe to exhibit low alpha/Fe ratios on their surfaces while they are on the main-sequence, because dwarfs have shallow surface convection zones where the engulfed matter is mixed. After the stars leave the main-sequence, the surface convection zones become deeper to reduce the enhancement of Fe. Eventually, when the stars ascend to the tip of the red giant branch, they engulf giant planets to become low-alpha stars again as observed in dwarf spheroidal galaxies. We predict that low-alpha stars with low Mn/Fe ratios harbor planetary systems.

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

    E-Print Network [OSTI]

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

    2003-03-27T23:59:59.000Z

    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.

  6. Does There Really Exist the Problem of the Dark Matter in Spiral Galaxies?

    E-Print Network [OSTI]

    A. E. Filippov; A. S. Zhedanov

    1995-11-04T23:59:59.000Z

    A simple model for the dust media describing evolution of the system like spiral galaxy is considered. In contrast to previous considerations we show that the initial density fold should be quasi-one-dimensional (bar-like) instead of disc-like. The disc component of the galaxies appears only during the evolution. The model naturally reproduces some essential features of the galaxies. In particular, it reproduces all the observed typical forms of the rotation curves for the spiral galaxies with a characteristic minimum and plateau. It appears that the plateau corresponds to escaping the matter (external spiral arms, due to initial conditions, have too large velocities to be confined by the gravitational field of the galaxy). Such a scenario of the galaxy evolution leads to the conclusion that the hypothesis of the dark matter is not necessary (at least, for the spiral galaxies).

  7. Matter as Curvature and Torsion of General Metric-Affine Space

    E-Print Network [OSTI]

    Alex Karpelson

    2014-06-25T23:59:59.000Z

    General equations of the unified geometric field theory, based on the curved and torsional space-time, are presented. They contain only geometrical parameters of the metric-affine space G4 and describe distribution and motion of the matter, which represents curvature and torsion of the space-time. Equations describing spherically symmetric non-stationary and stationary fields are derived for various cases: for metrics with singularities and without them, for gravitational field in vacuum and for the massless fluid with spin. Equations describing uniform isotropic field are derived for the closed and open isotropic models of universe for the gravitational field in vacuum and for the massless fluid with spin; some of these equations and their solutions coincide with the respective equations and their solutions in general relativity for the space filled with the dust-like matter.

  8. Matter in the Bulk and its Consequences on the Brane: A Possible Source of Dark Energy

    E-Print Network [OSTI]

    Subenoy Chakraborty; Asit Banerjee; Tanwi Bandyopadhyay

    2007-07-02T23:59:59.000Z

    The usual brane world scenario with anti de Sitter bulk has been generalized by considering a general form of energy momentum tensor in the bulk. The modified Einstein equation on the brane has been constructed. Two examples have been cited of which, the first one shows the usual brane equations when matter in the bulk is a negative cosmological constant. In the second example, the bulk matter is in the form of perfect fluid and as a result, an effective perfect fluid is obtained in the brane. Also it is noted that the effect of the dust bulk on the brane shows a dark energy behaviour and may be a possible explanation of the dark energy from the present day observational point of view.

  9. Collapse Dynamics of a Star of Dark Matter and Dark Energy

    E-Print Network [OSTI]

    Subenoy Chakraborty; Tanwi Bandyopadhyay

    2006-09-12T23:59:59.000Z

    In this work, we study the collapse dynamics of an inhomogeneous spherically symmetric star made of dark matter (DM) and dark energy (DE). The dark matter is taken in the form of a dust cloud while anisotropic fluid is chosen as the candidate for dark energy. It is investigated how dark energy modifies the collapsing process and is examined whether dark energy has any effect on the Cosmic Censorship Conjecture. The collapsing star is assumed to be of finite radius and the space time is divided into three distinct regions $\\Sigma$ and $V^{\\pm}$, where $\\Sigma$ represents the boundary of the star and $V^{-}(V^{+})$ denotes the interior (exterior) of the star. The junction conditions for matching $V^{\\pm}$ over $\\Sigma$ are specified. Role of Dark energy in the formation of apparent horizon is studied and central singularity is analyzed.

  10. THE SPATIAL DISTRIBUTION OF DUST AND STELLAR EMISSION OF THE MAGELLANIC CLOUDS

    SciTech Connect (OSTI)

    Skibba, Ramin A.; Engelbracht, Charles W.; Misselt, Karl; Montiel, Edward [Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Aniano, Gonzalo [Princeton University Observatory, Peyton Hall, Princeton, NJ 08544 (United States); Babler, Brian [Department of Astronomy, 475 North Charter St., University of Wisconsin, Madison, WI 53706 (United States); Bernard, Jean-Philippe [Universite de Toulouse, UPS-OMP, IRAP, Toulouse (France); Bot, Caroline [Universite de Strasbourg, Observatoire Astronomique de Strasbourg, F-67000 Strasbourg (France); Carlson, Lynn Redding; Israel, Frank [Sterrewacht Leiden, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Galametz, Maud [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Galliano, Frederic; Hony, Sacha; Lebouteiller, Vianney; Madden, Suzanne; Okumura, Koryo; Panuzzo, Pasquale [AIM, CEA/Saclay, L'Orme des Merisiers, 91191 Gif-sur-Yvette (France); Gordon, Karl; Meixner, Margaret [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Li, Aigen, E-mail: rskibba@ucsd.edu [314 Physics Building, Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211 (United States); and others

    2012-12-10T23:59:59.000Z

    We study the emission by dust and stars in the Large and Small Magellanic Clouds, a pair of low-metallicity nearby galaxies, as traced by their spatially resolved spectral energy distributions. This project combines Herschel Space Observatory PACS and SPIRE far-infrared photometry with other data at infrared and optical wavelengths (the data were obtained as part of the HERschel Inventory of The Agents of Galaxy Evolution survey; PI: M. Meixner). We build maps of dust, stellar luminosity, and mass of both Magellanic Clouds, and analyze the spatial distribution of dust/stellar luminosity and mass ratios. These ratios vary considerably throughout the galaxies, generally between the range 0.01 {<=} L{sub dust}/L{sub *} {<=} 0.6 and 10{sup -4} {<=} M{sub dust}/M{sub *} {<=} 4 Multiplication-Sign 10{sup -3}. We observe that the dust/stellar ratios depend on the interstellar medium environment, such as the distance from currently or previously star-forming regions, and on the intensity of the interstellar radiation field. In addition, we construct star formation rate (SFR) maps, and find that the SFR is correlated with the dust/stellar luminosity and dust temperature in both galaxies, demonstrating the relation between star formation, dust emission, and heating, though these correlations exhibit substantial scatter.

  11. age-dependent dust heating: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    correlations. Zeljko Ivezic; Moshe Elitzur 1996-12-17 17 Spatial distribution of Far infrared emission in spiral galaxies II. Heating sources and gas-to-dust ratio...

  12. Effects of climate, physical erosion, parent mineralogy, and dust on chemical erosion rates in mountainous terrain

    E-Print Network [OSTI]

    Ferrier, Ken

    2009-01-01T23:59:59.000Z

    Bryan, K. , 1927. The ”Palouse soil” problem. USGS Bulletinin the Channeled Scablands and Palouse of Washington State.dust-producing engine of the Palouse loess, USA. Quaternary

  13. Cement kiln flue dust as a source of lime and potassium in four East Texas soils

    E-Print Network [OSTI]

    Poole, Warren David

    1975-01-01T23:59:59.000Z

    design on both sites. Yield, soil pH, plant and soil concentrations of K, Ca, and Mg were determined. Soil pH and extractable Ca increased with increasing rate of flue dust or calcite. Under field conditions, flue dust compared favorably with calcite... was similar to plant uptake from corresponding calcite + KC1 treatments. Soil pH and extractable soil K, Ca, and Mg increased with increased rate of flue dust treatment equally as well as from the corresponding calcite treatments. The flue dust was equal...

  14. THE CHEMICALLY CONTROLLED SYNTHESIS OF DUST IN TYPE II-P SUPERNOVAE

    SciTech Connect (OSTI)

    Sarangi, Arkaprabha; Cherchneff, Isabelle, E-mail: arkaprabha.sarangi@unibas.ch, E-mail: isabelle.cherchneff@unibas.ch [Departement Physik, Universität Basel, CH-4056 Basel (Switzerland)

    2013-10-20T23:59:59.000Z

    We study the formation of molecules and dust clusters in the ejecta of solar metallicity, Type II-P supernovae (SNe) using a chemical kinetic approach. We follow the evolution of molecules and small dust cluster masses from day 100 to day 1500 after explosion. We consider stellar progenitors with initial masses of 12, 15, 19, and 25 M{sub ?} that explode as SNe with stratified ejecta. The molecular precursors to dust grains comprise molecular chains, rings and small clusters of silica, silicates, metal oxides, sulfides and carbides, pure metals, and carbon, where the nucleation of silicate clusters is described by a two-step process of metal and oxygen addition. We study the impact of the {sup 56}Ni mass on the type and amount of synthesized dust. We predict that large masses of molecules including CO, SiO, SiS, O{sub 2}, and SO form in the ejecta. We show that the discrepancy between the small dust masses detected at infrared wavelengths some 500 days post-explosion and the larger amounts of dust recently detected with Herschel in SN remnants can be explained by the non-equilibrium chemistry linked to the formation of molecules and dust clusters in the ejected material. Dust gradually builds up from small (?10{sup –5} M{sub ?}) to large masses (?5 × 10{sup –2} M{sub ?}) over a 5 yr period after explosion. Subsequent dust formation and/or growth is hampered by the shortage of chemical agents participating in the dust nucleation and the long timescale for accretion. The results highlight the dependence of the dust chemical composition and mass on the amount of {sup 56}Ni synthesized during the explosion. This dependence may partly explain the diversity of epochs at which dust forms in SNe. More generally, our results indicate that Type II-P SNe are efficient but moderate dust producers with an upper limit on the mass of synthesized dust ranging from ?0.03 to 0.09 M{sub ?}. Other dust sources must then operate at high redshift to explain the large quantities of dust present in young galaxies in the early universe.

  15. Smoke-plume distributions above large-scale fires: Implications for simulations of ''nuclear winter''

    SciTech Connect (OSTI)

    Penner, J.E.; Haselman L. Jr.; Edwards, L.L.

    1986-10-01T23:59:59.000Z

    Smoke from raging fires produced in the aftermath of a major nuclear exchange has been predicted to cause large decreases in surface temperatures. However, the extent of the decrease and even the sign of the temperature change depend on how the smoke is distributed with altitude. We present a model capable of evaluating the initial distribution of lofted smoke above a massive fire. Calculations are shown for a two-dimensional slab version of the model and a full three-dimensional version. The model has been evaluated by simulating smoke heights for the Hamburg firestorm of 1943, and a smaller-scale oil fire which occurred in Long Beach in 1958. Our plume heights for these fires are compared to those predicted by the classical Morton-Taylor-Turner theory for weakly buoyant plumes. We consider the effect of the added buoyancy caused by condensation of waterladen ground level air being carried to high altitude with the convection column, as well as the effects of background wind on the calculated smoke plume heights for several fire intensities. We find that the rise height of the plume depends on the assumed background atmospheric conditions, as well as the fire intensity.

  16. Laser Driven Dynamic Loading of Condensed Matter

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Laser Driven Dynamic Loading of Condensed Matter Laser Driven Dynamic Loading of Condensed Matter Advanced diagnostics of experiments covering many orders of magnitude in strain...

  17. A classification of spherically symmetric self-similar dust models

    E-Print Network [OSTI]

    B. J. Carr

    2000-03-02T23:59:59.000Z

    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.

  18. The Energy of Charged Matter

    E-Print Network [OSTI]

    Jan Philip Solovej

    2004-06-07T23:59:59.000Z

    In this talk I will discuss some of the techniques that have been developed over the past 35 years to estimate the energy of charged matter. These techniques have been used to solve stability of (fermionic) matter in different contexts, and to control the instability of charged bosonic matter. The final goal will be to indicate how these techniques with certain improvements can be used to prove Dyson's 1967 conjecture for the energy of a charged Bose gas--the sharp $N^{7/5}$ law.

  19. The Unification and Cogeneration of Dark Matter and Baryonic Matter

    E-Print Network [OSTI]

    S. M. Barr

    2011-09-18T23:59:59.000Z

    In grand unified theories with gauge groups larger than SU(5), the multiplets that contain the known quarks and leptons also contain fermions that are singlets under the Standard Model gauge group. Some of these could be the dark matter of the universe. Grand unified theories can also have accidental U(1) global symmetries (analogous to B-L in minimal SU(5)) that can stabilize dark matter. These ideas are illustrated in an SU(6) model.

  20. The Unification and Cogeneration of Dark Matter and Baryonic Matter

    E-Print Network [OSTI]

    Barr, S M

    2011-01-01T23:59:59.000Z

    In grand unified theories with gauge groups larger than SU(5), the multiplets that contain the known quarks and leptons also contain fermions that are singlets under the Standard Model gauge group. Some of these could be the dark matter of the universe. Grand unified theories can also have accidental U(1) global symmetries (analogous to B-L in minimal SU(5)) that can stabilize dark matter. These ideas are illustrated in an SU(6) model.

  1. Volumetric measurements of a spatially growing dust acoustic wave

    SciTech Connect (OSTI)

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

    2012-11-15T23:59:59.000Z

    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.

  2. Geometrodynamics in a spherically symmetric, static crossflow of null dust

    E-Print Network [OSTI]

    Zsolt Horváth; Zoltán Kovács; László Á. Gergely

    2006-10-12T23:59:59.000Z

    The spherically symmetric, static spacetime generated by a crossflow of non-interacting radiation streams, treated in the geometrical optics limit (null dust) is equivalent to an anisotropic fluid forming a radiation atmosphere of a star. This reference fluid provides a preferred / internal time, which is employed as a canonical coordinate. Among the advantages we encounter a new Hamiltonian constraint, which becomes linear in the momentum conjugate to the internal time (therefore yielding a functional Schr\\"{o}dinger equation after quantization), and a strongly commuting algebra of the new constraints.

  3. Geometrodynamics in a spherically symmetric, static crossflow of null dust

    E-Print Network [OSTI]

    Horváth, Z; Kovács, Z; Horv\\'{a}th, Zsolt; Kov\\'{a}cs, Zolt\\'{a}n

    2006-01-01T23:59:59.000Z

    The spherically symmetric, static spacetime generated by a crossflow of non-interacting radiation streams, treated in the geometrical optics limit (null dust) is equivalent to an anisotropic fluid forming a stellar atmosphere. This reference fluid provides a preferred / internal time, which is employed as a canonical coordinate. Among the advantages we encounter a new Hamiltonian constraint, which becomes linear in the momentum conjugate to the internal time (therefore yielding a functional Schr\\"{o}dinger equation after quantization), and a strongly commuting algebra of the new constraints.

  4. Dust: A major environmental hazard on the earth's moon

    SciTech Connect (OSTI)

    Heiken, G.; Vaniman, D.; Lehnert, B.

    1990-01-01T23:59:59.000Z

    On the Earth's Moon, obvious hazards to humans and machines are created by extreme temperature fluctuations, low gravity, and the virtual absence of any atmosphere. The most important other environmental factor is ionizing radiation. Less obvious environmental hazards that must be considered before establishing a manned presence on the lunar surface are the hazards from micrometeoroid bombardment, the nuisance of electro-statically-charged lunar dust, and an alien visual environment without familiar clues. Before man can establish lunar bases and lunar mining operations, and continue the exploration of that planet, we must develop a means of mitigating these hazards. 4 refs.

  5. Space Dust Analysis Could Provide Clues to Solar System Origins

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our Instagram Secretary Moniz9MorganYouofSolvingexplore correlation613Space Dust

  6. Space Dust Analysis Could Provide Clues to Solar System Origins

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del Sol HomeFacebookScholarship Fund3Biology|Solar windMarch 26,SowjanyaSpaceSpace Dust

  7. Dust Defeats Germ-Killing Fabrics | Jefferson Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField Campaign:INEA :Work with Jefferson Lab | JeffersonDurableDurgishDust

  8. Passive cigarette smoke, coal heating, and respiratory symptoms of nonsmoking women in China

    SciTech Connect (OSTI)

    Pope, C.A. III (Harvard School of Public Health, Boston, MA (United States) Brigham Young Univ., Provo, UT (United States)); Xu, X. (Harvard School of Public Health, Boston, MA (United States))

    1993-09-01T23:59:59.000Z

    In this study the authors evaluated data from a sample of 973 never-smoking women, ages 20-40, who worked in three similar textile mills in Anhui Province, China. They compared prevalence rates of respiratory symptoms across homes with and without coal heating and homes with different numbers of smokers. Multiple logistic regression models that controlled for age, job title, and mill of employment were also estimated. Respiratory symptoms were associated with combined exposure to passive cigarette smoke and coal heating. Effects of passive cigarette smoke and coal heating on respiratory symptoms appeared to be nearly additive, suggesting a dose-response relationship between respiratory symptoms and home indoor air pollution from these two sources. The prevalence of chest illness, cough, phlegm, and shortness of breath (but not wheeze) was significantly elevated for women living in homes with both smokers and coal heating.

  9. A Strong Correlation between Circumnuclear Dust and Black Hole Accretion in Early-Type Galaxies

    E-Print Network [OSTI]

    Ramiro D. Simões Lopes; Thaisa Storchi-Bergmann; Maria de Fátima O. Saraiva; Paul Martini

    2006-10-12T23:59:59.000Z

    We present a detailed investigation of the incidence of circumnuclear dust structure in a large, well-matched sample of early-type galaxies with and without Active Galactic Nuclei (AGN). All 34 early-type AGN hosts in our sample have circumnuclear dust, while dust is only observed in 26% (nine) of a pair-matched sample of 34 early-type, inactive galaxies. This result demonstrates a strong correlation between the presence of circumnuclear dust and accretion onto the central, supermassive black hole in elliptical and lenticular galaxies. This correlation is not present at later Hubble types, where a sample of 31 active and 31 inactive galaxies all contain circumnuclear dust. These archival, HST observations reveal a wide range of mostly chaotic dust morphologies. Current estimates suggest the dust settling or destruction time is on order of 10^8 years and therefore the presence of dust in ~ 50% of early-type galaxies requires frequent replenishment and similarly frequent fueling of their central, supermassive black holes. The observed dust could be internally-produced (via stellar winds) or externally-accreted, although there are observational challenges for both of these scenarios. Our analysis also reveals that approximately a third of the early-type galaxies without circumnuclear dust have nuclear stellar disks. These nuclear stellar disks may provide a preferred kinematic axis to externally-accreted material and this material may in turn form new stars in these disks. The observed incidence of nuclear stellar disks and circumnuclear dust suggests that episodic replenishment of nuclear stellar disks occurs and is approximately concurrent with the fueling of the central AGN.

  10. LUNAR DUST GRAIN CHARGING BY ELECTRON IMPACT: COMPLEX ROLE OF SECONDARY ELECTRON EMISSIONS IN SPACE ENVIRONMENTS

    SciTech Connect (OSTI)

    Abbas, M. M.; Craven, P. D.; LeClair, A. C.; Spann, J. F. [NASA-Marshall Space Flight Center, Huntsville, AL 35812 (United States); Tankosic, D., E-mail: Mian.M.Abbas@nasa.go [USRA/NASA-Marshall Space Flight Center, Huntsville, AL 35805 (United States)

    2010-08-01T23:59:59.000Z

    Dust grains in various astrophysical environments are generally charged electrostatically by photoelectric emissions with radiation from nearby sources, or by electron/ion collisions by sticking or secondary electron emissions (SEEs). The high vacuum environment on the lunar surface leads to some unusual physical and dynamical phenomena involving dust grains with high adhesive characteristics, and levitation and transportation over long distances. Knowledge of the dust grain charges and equilibrium potentials is important for understanding a variety of physical and dynamical processes in the interstellar medium, and heliospheric, interplanetary/planetary, and lunar environments. It has been well recognized that the charging properties of individual micron-/submicron-size dust grains are expected to be substantially different from the corresponding values for bulk materials. In this paper, we present experimental results on the charging of individual 0.2-13 {mu}m size dust grains selected from Apollo 11 and 17 dust samples, and spherical silica particles by exposing them to mono-energetic electron beams in the 10-200 eV energy range. The dust charging process by electron impact involving the SEEs discussed is found to be a complex charging phenomenon with strong particle size dependence. The measurements indicate substantial differences between the polarity and magnitude of the dust charging rates of individual small-size dust grains, and the measurements and model properties of corresponding bulk materials. A more comprehensive plan of measurements of the charging properties of individual dust grains for developing a database for realistic models of dust charging in astrophysical and lunar environments is in progress.

  11. Evolving Einstein's Field Equations with Matter: The ``Hydro without Hydro'' Test

    E-Print Network [OSTI]

    Thomas W. Baumgarte; Scott A. Hughes; Stuart L. Shapiro

    1999-02-09T23:59:59.000Z

    We include matter sources in Einstein's field equations and show that our recently proposed 3+1 evolution scheme can stably evolve strong-field solutions. We insert in our code known matter solutions, namely the Oppenheimer-Volkoff solution for a static star and the Oppenheimer-Snyder solution for homogeneous dust sphere collapse to a black hole, and evolve the gravitational field equations. We find that we can evolve stably static, strong-field stars for arbitrarily long times and can follow dust sphere collapse accurately well past black hole formation. These tests are useful diagnostics for fully self-consistent, stable hydrodynamical simulations in 3+1 general relativity. Moreover, they suggest a successive approximation scheme for determining gravitational waveforms from strong-field sources dominated by longitudinal fields, like binary neutron stars: approximate quasi-equilibrium models can serve as sources for the transverse field equations, which can be evolved without having to re-solve the hydrodynamical equations (``hydro without hydro'').

  12. Passive smoking, air pollution, and acute respiratory symptoms in a diary study of student nurses

    SciTech Connect (OSTI)

    Schwartz, J.; Zeger, S. (Environmental Protection Agency, Washington, DC (USA))

    1990-01-01T23:59:59.000Z

    A cohort of approximately 100 student nurses in Los Angeles was recruited for a diary study of the acute effects of air pollution. Smoking histories and presence of asthma and other allergies were determined by questionnaire. Diaries were completed daily and collected weekly for as long as 3 yr. Air pollution was measured at a monitoring location within 2.5 miles of the school. Incidence and duration of a symptom were modeled separately. Pack-years of cigarettes were predictive of the number of episodes of coughing (p less than 0.0001) and of bringing up phlegm (p less than 0.0001). Current smoking, rather than cumulative smoking, was a better predictor of the duration of a phlegm episode (p less than 0.0001). Controlling for personal smoking, a smoking roommate increased the risk of an episode of phlegm (odds ratio (OR) = 1.41, p less than 0.001), but not of cough. Excluding asthmatics (who may be medicated), increased the odds ratio for passive smoking to 1.76 (p less than 0.0001). In logistic regression models controlling for temperature and serial correlation between days, an increase of 1 SD in carbon monoxide exposure (6.5 ppm) was associated with increased risk of headache (OR = 1.09, p less than 0.001), photochemical oxidants (7.4 pphm) were associated with increased risk of chest discomfort (OR = 1.17, p less than 0.001) and eye irritation (OR = 1.20 p less than 0.001), and nitrogen dioxide (9.1 pphm) was associated with increased risk of phlegm (OR = 1.08 p less than 0.01), sore throats (OR = 1.26, p less than 0.001), and eye irritation (OR = 1.16, p less than 0.001).

  13. Circuit bridging of digital equipment caused by smoke from a cable fire

    SciTech Connect (OSTI)

    Tanaka, T.J.; Anderson, D.J.

    1997-03-01T23:59:59.000Z

    Advanced reactor systems are likely to use protection systems with digital electronics that ideally should be resistant to environmental hazards, including smoke from possible cable fires. Previous smoke tests have shown that digital safety systems can fail even at relatively low levels of smoke density and that short-term failures are likely to be caused by circuit bridging. Experiments were performed to examine these failures, with a focus on component packaging and protection schemes. Circuit bridging, which causes increased leakage currents and arcs, was gauged by measuring leakage currents among the leads of component packages. The resistance among circuit leads typically varies over a wide range, depending on the nature of the circuitry between the pins, bias conditions, circuit board material, etc. Resistance between leads can be as low as 20 k{Omega} and still be good, depending on the component. For these tests, the authors chose a printed circuit board and components that normally have an interlead resistance above 10{sup 12} {Omega}, but if the circuit is exposed to smoke, circuit bridging causes the resistance to fall below 10{sup 3} {Omega}. Plated-through-hole (PTH) and surface-mounted (SMT) packages were exposed to a series of different smoke environments using a mixture of environmentally qualified cables for fuel. Conformal coatings and enclosures were tested as circuit protection methods. High fuel levels, high humidity, and high flaming burns were the conditions most likely to cause circuit bridging. The inexpensive conformal coating that was tested - an acrylic spray - reduced leakage currents, but enclosure in a chassis with a fan did not. PTH packages were more resistant to smoke-induced circuit bridging than SMT packages. Active components failed most often in tests where the leakage currents were high, but failure did not always accompany high leakage currents.

  14. Physical Protection of Classified Matter

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    1988-02-03T23:59:59.000Z

    The order establishes policy and objectives for physical protection of classified matter. This directive does not cancel another directive. Chg 1, 7-30-93. Canceled by 5632.1C.

  15. A mixed-methods study of young adults’ receptivity to using Facebook for smoking cessation: If you build it, will they come?

    E-Print Network [OSTI]

    Ramo, Danielle E; Liu, Howard; Prochaska, Judith J

    2013-01-01T23:59:59.000Z

    Development; 2008. AppData. Facebook Apps Leaderboard.use among young people. Facebook for smoking cessationBMC Public Health. 2009;9:32. Facebook for smoking cessation

  16. "Smoking Cessation Interventions and Program Availability for Drug and Alcohol Addicted Low Income Populations in Substance Abuse Treatment"

    E-Print Network [OSTI]

    Arnold, Jonathan

    "Smoking Cessation Interventions and Program Availability for Drug and Alcohol Addicted Low Income. The first aim examines longitudinally the availability of EBTs for smoking among those seeking treatment for co-occurring substance abuse and explores the predictors of changes in service availability over time

  17. Quantification of the Aerosol Direct Radiative Effect from Smoke over Clouds Using Passive Space-borne Spectrometry

    E-Print Network [OSTI]

    Tilstra, Gijsbert

    Quantification of the Aerosol Direct Radiative Effect from Smoke over Clouds Using Passive Space cloud radiative effects in the shortwave infrared (SWIR). In the UV, aerosol absorption from smoke to the aerosol direct radiative effect (DRE). AEROSOL DIRECT RADIATIVE EFFECT OVER CLOUDS A radiative forcing

  18. Quantification of the Aerosol Direct Radiative Effect from Smoke over Clouds using Passive Space-borne Spectrometry

    E-Print Network [OSTI]

    Graaf, Martin de

    Quantification of the Aerosol Direct Radiative Effect from Smoke over Clouds using Passive Space cloud radiative effects in the shortwave infrared (SWIR). In the UV, aerosol absorption from smoke to the aerosol direct radiative effect (DRE). AEROSOL DIRECT RADIATIVE EFFECT OVER CLOUDS A radiative forcing

  19. Cosmology, Thermodynamics and Matter Creation

    E-Print Network [OSTI]

    J. A. S. Lima; M. O. Calvao; I. Waga

    2007-08-24T23:59:59.000Z

    Several approaches to the matter creation problem in the context of cosmological models are summarily reviewed. A covariant formulation of the general relativistic imperfect simple fluid endowed with a process of matter creation is presented. By considering the standard big bang model, it is shown how the recent results of Prigogine et alii \\cite{1} can be recovered and, at the same time their limits of validity are explicited.

  20. ?CDM cosmology from matter only

    E-Print Network [OSTI]

    Herman Telkamp

    2015-04-08T23:59:59.000Z

    I discuss a matter-only interpretation of {\\Lambda}CDM cosmology, based on conservation of energy and assuming a Machian definition of inertia. {\\Lambda}CDM cosmology can be linked to a Newtonian cosmic potential, subject to a propagating gravitational horizon. In a matter-only universe where total energy is conserved, Machian inertia related to the evolving potential may cause both deceleration and acceleration of recession.

  1. Shear viscosity of nuclear matter

    E-Print Network [OSTI]

    Jun Xu

    2013-02-01T23:59:59.000Z

    In this talk I report my recent study on the shear viscosity of neutron-rich nuclear matter from a relaxation time approach. An isospin- and momentum-dependent interaction is used in the study. Effects of density, temperature, and isospin asymmetry of nuclear matter on its shear viscosity have been discussed. Similar to the symmetry energy, the symmetry shear viscosity is defined and its density and temperature dependence are studied.

  2. Dark Matter Triggers of Supernovae

    E-Print Network [OSTI]

    Peter W. Graham; Surjeet Rajendran; Jaime Varela

    2015-05-17T23:59:59.000Z

    The transit of primordial black holes through a white dwarf causes localized heating around the trajectory of the black hole through dynamical friction. For sufficiently massive black holes, this heat can initiate runaway thermonuclear fusion causing the white dwarf to explode as a supernova. The shape of the observed distribution of white dwarfs with masses up to $1.25 M_{\\odot}$ rules out primordial black holes with masses $\\sim 10^{19}$ gm - $10^{20}$ gm as a dominant constituent of the local dark matter density. Black holes with masses as large as $10^{24}$ gm will be excluded if recent observations by the NuStar collaboration of a population of white dwarfs near the galactic center are confirmed. Black holes in the mass range $10^{20}$ gm - $10^{22}$ gm are also constrained by the observed supernova rate, though these bounds are subject to astrophysical uncertainties. These bounds can be further strengthened through measurements of white dwarf binaries in gravitational wave observatories. The mechanism proposed in this paper can constrain a variety of other dark matter scenarios such as Q balls, annihilation/collision of large composite states of dark matter and models of dark matter where the accretion of dark matter leads to the formation of compact cores within the star. White dwarfs, with their astronomical lifetimes and sizes, can thus act as large space-time volume detectors enabling a unique probe of the properties of dark matter, especially of dark matter candidates that have low number density. This mechanism also raises the intriguing possibility that a class of supernova may be triggered through rare events induced by dark matter rather than the conventional mechanism of accreting white dwarfs that explode upon reaching the Chandrasekhar mass.

  3. Correlation between smoke opacities as determined by transmissometer readings and visual observations

    E-Print Network [OSTI]

    Martin, John Herschel

    1973-01-01T23:59:59.000Z

    el Number d 0 cit Ringelmann Number Opaoity 20$ 6+5 Smf 10+ The Ringelmann smoke chart which he created for use as a field reference oonsists of four separate charts (Ringelmann numbers one through four?-number aero whioh is all white...~uirement for the degree of MASTER OF SCIENCE December 19'73 Na]or Sub)cot~ Chemical Engineering CORRELATION BETWEEN SMOKE OPACITIES AS DETERMINED BY TRANSMISSOMETER READINGS AND VISUhL OBSERVATIONS A Thesis by JOHN HERSCHEL MARTIN Approved as to style...

  4. A comparison of Tennessee Williams' Summer and smoke and The eccentricities of a nightingale

    E-Print Network [OSTI]

    Boyd, Shirley Lois

    1978-01-01T23:59:59.000Z

    A COMPARISON OF TENNESSEE WILLIAMS ' SUMMER AND SMOKE AND THE ECCENTRICITIES OF A N1GHT1NGALE A Thesi s by S HIRLEY LOIS BOYD Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree... of MASTER OF ARTS May 197B Major Subject: English A COMPARISON OF TENNESSEE WILLIAMS' SUMMER AND SMOKE AND THE ECCENTRICITIES OF A NIGHTINGALE A Thesi s by SHIRLEY LOIS BOYD Approved as to style and content by: g'~t. &i7 'i IL. Chairman of Commi...

  5. Analysis of forest-fire smoke using satellite imagery. Master's thesis

    SciTech Connect (OSTI)

    De Vries, P.J.

    1989-03-01T23:59:59.000Z

    NOAA-9 AVHRR data from 17 and 18 September 1987 were used to perform forest-fire smoke analysis and tracking. The analysis included alignment, subtraction and division of image digital values to produce an Aerosol Particle Size Index (S12) after Frost (1988). S12 provides information about the slope of the aerosol particle size distribution curve and can be used to infer particle-size distribution changes over time. The results provide evidence that the smoke aging process may be successfully studied using satellite imagery, provided careful analysis and removal of background effects are performed.

  6. Two field matter bounce cosmology

    SciTech Connect (OSTI)

    Cai, Yi-Fu; McDonough, Evan; Duplessis, Francis; Brandenberger, Robert H., E-mail: yifucai@physics.mcgill.ca, E-mail: evanmc@physics.mcgill.ca, E-mail: francis.duplessis@mail.mcgill.ca, E-mail: rhb@hep.physics.mcgill.ca [Department of Physics, McGill University, Montréal, QC H3A 2T8 (Canada)

    2013-10-01T23:59:59.000Z

    We re-examine the non-singular Matter Bounce scenario first developed in [20], which starts with a matter-dominated period of contraction and transitions into an Ekpyrotic phase of contraction. We consider both matter fields, the first of which plays the role of regular matter, and the second of which is responsible for the non-singular bounce. Since the dominant matter field is massive, the induced curvature fluctuations are initially not scale-invariant, whereas the fluctuations of the second scalar field (which are initially entropy fluctuations) are scale-invariant. We study the transfer of the initial entropy perturbations into curvature fluctuations in the matter-dominated phase of contraction and show that the latter become nearly scale invariant on large scales but are blue tilted on small scales. We study the evolution of both curvature and entropy fluctuations through the bounce, and show that both have a scale-invariant spectrum which is blue-tilted on small scales. However, we find that the entropy fluctuations have an amplitude that is much smaller than that of the curvature perturbations, due to gravitational amplification of curvature perturbations during the bounce phase.

  7. Coulomb interactions between dust particles in plasma etching reactors

    SciTech Connect (OSTI)

    Hwang, H.H.; Kushner, M.J. [Univ. of Illinois, Urbana, IL (United States). Dept. of Electrical and Computer Engineering

    1996-12-31T23:59:59.000Z

    Wafer contamination by particles, or dust, in plasma processing reactors remains a continuing concern in the microelectronics industry. Particles charge negatively in low temperature plasmas and resemble electrically floating bodies. The transport of these particles in plasma processing reactors is dominated by electrostatic, ion-drag, fluid-drag, and thermophoretic forces. Under conditions where the particle density is large, Debye shielding may be insufficient to isolate the particles, leading to particle-particle Coulomb interactions. Such interactions are likely to occur in trapping locations, which are typically near the plasma-sheath boundaries in Reactive Ion Etching (RIE) discharges. Particles that experience Coulomb interactions may display collective behavior, an extreme example being a Coulomb liquid or solid. Particle transport in plasma processing reactors has been studied extensively to predict rates of wafer contamination thought to date particle-particle interactions have not been addressed. In this paper, the authors discuss results from a computer model for dust particle transport in RIE discharges where particle-particle Coulomb interactions are included.

  8. Ice Nuclei in Marine Air: Biogenic Particles or Dust?

    SciTech Connect (OSTI)

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

    2013-01-11T23:59:59.000Z

    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.

  9. Spectral solar irradiance before and during a Harmattan dust spell

    SciTech Connect (OSTI)

    Adeyefa, Z.D. [Federal Univ. of Technology, Akure (Nigeria)] [Federal Univ. of Technology, Akure (Nigeria); Holmgren, B. [Uppsala Univ. (Sweden)] [Uppsala Univ. (Sweden)

    1996-09-01T23:59:59.000Z

    Measurements of the ground-level spectral distributions of the direct, diffuse and global solar irradiance between 300 and 1100 nm were made at Akure (7.15{degree}N, 5.5{degree}E), Nigeria, in December 1991 before and during a Harmattan dust spell employing a spectroradiometer (LICOR LI-1800) with 6 nm resolution. The direct spectral solar irradiance which was initially reduced before the dust storm was further attenuated by about 50% after the spell. Estimated values of the Angstrom turbidity coefficient {beta} indicated an increase of about 146% of this parameter while the Angstrom wavelength-exponent {alpha} decreased by about 65% within the 2-day study period. The spectral diffuse-to-direct and diffuse-to-global ratios suggest that the main cause of the significant reduction in solar irradiance at the surface was the scattering by the aerosol which led to an increase in the diffuse component. The global irradiance though reduced, was less sensitive to changing Harmattan conditions. It is recommended that solar energy devices that use radiation from Sun and sky be used under fluctuating Harmattan conditions. There are some deviations from the Angstrom formula under very turbid Harmattan conditions which could be explained by the relative increase of the particle sizes. 31 refs., 12 figs., 3 tabs.

  10. Direct Observation of Completely Processed Calcium Carbonate Dust Particles

    SciTech Connect (OSTI)

    Laskin, Alexander; Iedema, Martin J.; Ichkovich, Aviad; Graber, Ellen R.; Taraniuk, Ilya; Rudich, Yinon

    2005-05-27T23:59:59.000Z

    This study presents, for the first time, field evidence of complete, irreversible processing of solid calcium carbonate (calcite)-containing particles and quantitative formation of liquid calcium nitrate particles apparently as a result of heterogeneous reaction of calcium carbonate-containing mineral dust particles with gaseous nitric acid. Formation of nitrates from individual calcite and sea salt particles was followed as a function of time in aerosol samples collected at Shoresh, Israel. Morphology and compositional changes of individual particles were observed using conventional scanning electron microscopy with energy dispersive analysis of X-rays (SEM/EDX) and computer controlled SEM/EDX. Environmental scanning electron microscopy (ESEM) was utilized to determine and demonstrate the hygroscopic behavior of calcium nitrate particles found in some of the samples. Calcium nitrate particles are exceptionally hygroscopic and deliquesce even at very low relative humidity (RH) of 9 -11% which is lower than typical atmospheric environments. Transformation of non-hygroscopic dry mineral dust particles into hygroscopic wet aerosol may have substantial impacts on light scattering properties, the ability to modify clouds and heterogeneous chemistry.

  11. MEMS `SMART DUST MOTES' FOR DESIGNING, MONITORING AND ENABLING EFFICIENT LIGHTING

    E-Print Network [OSTI]

    Agogino, Alice M.

    -based lighting system has the potential to achieve many environmental benefits in comparison to existing sensorMEMS `SMART DUST MOTES' FOR DESIGNING, MONITORING AND ENABLING EFFICIENT LIGHTING Alice M. Agogino focused on office lighting monitoring and control based on the new MEMS `smart dust mote' sensor

  12. BAYESIAN INFERENCE ON INTEGRATED CONTINUITY FLUID FLOWS AND THEIR APPLICATION TO DUST AEROSOLS

    E-Print Network [OSTI]

    Garbe, Christoph S.

    BAYESIAN INFERENCE ON INTEGRATED CONTINUITY FLUID FLOWS AND THEIR APPLICATION TO DUST AEROSOLS Waterloo, Ontario, Canada ABSTRACT The significant role dust aerosols play in the earth's cli- mate system models for aerosol de- tection and atmospheric transport that rely on latent Gaussian Markov random

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

    SciTech Connect (OSTI)

    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

    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.

  14. Direct climate effect of black carbon in China and its impact on dust storms

    E-Print Network [OSTI]

    Liou, K. N.

    Click Here for Full Article Direct climate effect of black carbon in China and its impact on dust aerosols in China, particularly black carbon (BC), is the primary reason for precipitation and temperature, W. Chen, and H. Liao (2010), Direct climate effect of black carbon in China and its impact on dust

  15. Mineralogy of Martian atmospheric dust inferred from thermal infrared spectra of aerosols

    E-Print Network [OSTI]

    Hamilton, Victoria E.

    Mineralogy of Martian atmospheric dust inferred from thermal infrared spectra of aerosols Victoria deconvolution algorithm to the spectra to model the dust mineralogy. Models of the M9 IRIS transmission data generally are of poor quality, and the mineralogical results of these fits are unlikely to be valid. Fits

  16. Dust Filtration by Planet-Induced Gap Edges: Implications for Transitional Disks

    E-Print Network [OSTI]

    Zhu, Zhaohuan; Dong, Ruobing; Espaillat, Catherine; Hartmann, Lee

    2012-01-01T23:59:59.000Z

    By carrying out two-dimensional two-fluid global simulations, we have studied the response of dust to gap formation by a single planet in the gaseous component of a protoplanetary disk - the so-called "dust filtration" mechanism. We have found that a gap opened by a giant planet at 20 AU in a \\alpha=0.01, \\dot{M}=10^{-8} Msun/yr disk can effectively stop dust particles larger than 0.1 mm drifting inwards, leaving a sub-millimeter dust cavity/hole. However, smaller particles are difficult to filter by a planet-induced gap due to 1) dust diffusion, and 2) a high gas accretion velocity at the gap edge. An analytic model is also derived to understand what size particles can be filtered by the gap edge. Finally, with our updated understanding of dust filtration, we have computed Monte-Carlo radiative transfer models with variable dust size distributions to generate the spectral energy distributions (SEDs) of disks with gaps. By comparing with transitional disk observations (e.g. GM Aur), we have found that dust fi...

  17. Tritium Behavior in Eroded Dust and Debris of Plasma-Facing Materials*

    E-Print Network [OSTI]

    Harilal, S. S.

    . & ,. 1. . . . Tritium Behavior in Eroded Dust and Debris of Plasma-Facing Materials* RECQVED SEP2 Reactor Materials (ICFRM-8) October 26-31, 1997, Sendai, Japan. qWork supported by the U.S. Department;. . . . . Tritium Behavior in Eroded Dust and Debris of Plasma-Facing Materials A. Hassanein', B. Wiechers2, and I

  18. Simulated Global Atmospheric Dust Distribution: Sensitivity to Regional Topography, Geomorphology, and Hydrology

    E-Print Network [OSTI]

    Zender, Charles

    , and Hydrology Charles S. Zender, Earth System Science Dept., UC Irvine, Irvine, CA 92697 (zender@uci.edu) David for predicting future trends in dust production. We identify three related geomorphologic and hydrologic hydrologically disturbed/renewed sed- iments. Dust models which attempt to account for sediment-rich source

  19. THE CHEMICAL IMPRINT OF SILICATE DUST ON THE MOST METAL-POOR STARS

    E-Print Network [OSTI]

    Bromm, Volker

    We investigate the impact of dust-induced gas fragmentation on the formation of the first low-mass, metal-poor stars (<1 M[subscript ?]) in the early universe. Previous work has shown the existence of a critical dust-to-gas ...

  20. Cancer Mortality and Wood Dust Exposure Among Participants in the American Cancer

    E-Print Network [OSTI]

    Salzman, Daniel

    Cancer Mortality and Wood Dust Exposure Among Participants in the American Cancer Society Cancer and Paolo Boffetta, MD, MPH3 In 1994, the International Agency for Research on Cancer (IARC) classified wood dust as a human carcinogen, based on very strong evidence of a carcinogenic risk of sino-nasal cancer

  1. Manure Harvesting Frequency: The Key to Feedyard Dust Control in a Summer Drought

    E-Print Network [OSTI]

    Auvermann, Brent W.; Parker, David B.; Sweeten, John M.

    2000-11-27T23:59:59.000Z

    Summer drought can make dust control in feedyards more challenging than usual. Supplemental water may not keep pace with daily evaporation. The key to dust control is managing the depth of dry manure in the pens by harvesting manure more frequently...

  2. Global observations and spectral characteristics of desert dust and biomass burning aerosols

    E-Print Network [OSTI]

    Graaf, Martin de

    Global observations and spectral characteristics of desert dust and biomass burning aerosols M. de (UV) absorbing aerosols, mainly desert dust and biomass burning aerosols. The AAI is not an aerosol quantity, but a radiation difference in the UV. Its main advantages are its insensitivity to scattering

  3. Temperature inversion on the surface of externally heated optically thick multigrain dust clouds

    E-Print Network [OSTI]

    Dejan Vinkovic

    2006-12-01T23:59:59.000Z

    It was recently discovered that the temperature in the surface layer of externally heated optically thick gray dust clouds increases with the optical depth for some distance from the surface, as opposed to the normal decrease in temperature with distance in the rest of the cloud. This temperature inversion is a result of efficient absorption of diffuse flux from the cloud interior by the surface dust exposed to the external radiation. A micron or bigger size grains experience this effect when the external flux is of stellar spectrum. We explore what happens to the effect when dust is a mixture of grain sizes (multigrain). Two possible boundary conditions are considered: i) a constant external flux without constrains on the dust temperature, and ii) the maximum dust temperature set to the sublimation temperature. We find that the first condition allows small grains to completely suppress the temperature inversion of big grains if the overall opacity is dominated by small grains. The second condition enables big grains to maintain the inversion even when they are a minor contributor to the opacity. In reality, the choice of boundary condition depends on the dust dynamics. When applied to the physics of protoplanetary disks, the temperature inversion leads to a previously unrecognized disk structure where optically thin dust can exist inside the dust destruction radius of an optically thick disk. We conclude that the transition between the dusty disk and the gaseous inner clearing is not a sharp edge, but rather a large optically thin region.

  4. Emission of non-thermal microwave radiation by a Martian dust storm Christopher Ruf,1

    E-Print Network [OSTI]

    Ruf, Christopher

    and forced by large-scale electric discharge. Thus, the non-thermal radiation was probably caused by electric#12;Emission of non-thermal microwave radiation by a Martian dust storm Christopher Ruf,1 Nilton O report evidence for the emission of non-thermal microwave radiation by a deep Martian dust storm

  5. Control of Black Spot of Roses with Sulphur-Copper Dust.

    E-Print Network [OSTI]

    Lyle, E. W. (Eldon W.)

    1944-01-01T23:59:59.000Z

    -off. Black spot was controlled with dusting (less than 0.1% of leaflet infection on September 23) and 3nt to ;easoll e and - - the CONTROL OF BLACK SPOT OF ROSES WITH SULPHUR-COPPER DUST 23 Table 10. Effect of time of cutting off understock tope...

  6. Tritium Containment in the Dust and Debris of Plasma-Facing Materials Produced During Operations

    E-Print Network [OSTI]

    Harilal, S. S.

    ' . . , . Tritium Containment in the Dust and Debris of Plasma-Facing Materials Produced During avaihble original document. #12;Tritium Containment in the Dust and Debris of Plasma-Facing hlaterials. IL 60439, USA Tritium behavior in plasma-facing components of future tokamak reactors such as ITER

  7. Effect of Electric Arc Furnace Bag House Dust on Concrete Durability Researcher: Fahad Al-Mutlaq

    E-Print Network [OSTI]

    Birmingham, University of

    Effect of Electric Arc Furnace Bag House Dust on Concrete Durability Researcher: Fahad Al billions of dollars annually. While steel is normally protected from corrosion in concrete by a passive of the effects of addition of Bag House Dust (BHD) on aspects of concrete durability. BHD is a fine powder

  8. Analysis of the effects of a proposed rule for the enforcement of respirable dust standards

    E-Print Network [OSTI]

    Britton, Robert Grant

    1996-01-01T23:59:59.000Z

    The effects of a rule for the enforcement of respirable dust standards proposed by the Mine Safety and Health Administration (MSHA) has been evaluated. Respirable coal dust sample data collected over a three year period by a mining company were used...

  9. Interactive dust-radiation modeling: A step to improve weather Carlos Perez,1

    E-Print Network [OSTI]

    radiative effects could lead to a significant improvement in the radiation balance of numerical weather 2002 is selected to assess the radiative dust effects on the atmosphere at a regional level. A strong unresolved and depend on the optical properties of dust, its vertical distribution, cloud cover, and albedo

  10. Observations of heterogeneous reactions between Asian pollution and mineral dust over the Eastern North Pacific during INTEX-B

    E-Print Network [OSTI]

    2009-01-01T23:59:59.000Z

    T. S. : Mixtures of pollution, dust, sea salt, and volcanicW. J. : Impact of air pollution on wet deposition of mineralreactions between Asian pollution and mineral dust doi:

  11. 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]

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

    2013-06-11T23:59:59.000Z

    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.

  12. DUST PROPERTIES AND DISK STRUCTURE OF EVOLVED PROTOPLANETARY DISKS IN Cep OB2: GRAIN GROWTH, SETTLING, GAS AND DUST MASS, AND INSIDE-OUT EVOLUTION

    SciTech Connect (OSTI)

    Sicilia-Aguilar, Aurora; Henning, Thomas; Dullemond, Cornelis P.; Bouwman, Jeroen; Sturm, Bernhard [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg (Germany); Patel, Nimesh [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Juhasz, Attila, E-mail: sicilia@mpia.de, E-mail: aurora.sicilia@uam.es [Leiden Observatory, Niels Bohrweg 2, NL-2333 CA Leiden (Netherlands)

    2011-11-20T23:59:59.000Z

    We present Spitzer/Infrared Spectrograph spectra of 31 T Tauri stars (TTS) and IRAM/1.3 mm observations for 34 low- and intermediate-mass stars in the Cep OB2 region. Including our previously published data, we analyze 56 TTS and 3 intermediate-mass stars with silicate features in Tr 37 ({approx}4 Myr) and NGC 7160 ({approx}12 Myr). The silicate emission features are well reproduced with a mixture of amorphous (with olivine, forsterite, and silica stoichiometry) and crystalline grains (forsterite, enstatite). We explore grain size and disk structure using radiative transfer disk models, finding that most objects have suffered substantial evolution (grain growth, settling). About half of the disks show inside-out evolution, with either dust-cleared inner holes or a radially dependent dust distribution, typically with larger grains and more settling in the innermost disk. The typical strong silicate features nevertheless require the presence of small dust grains, and could be explained by differential settling according to grain size, anomalous dust distributions, and/or optically thin dust populations within disk gaps. M-type stars tend to have weaker silicate emission and steeper spectral energy distributions than K-type objects. The inferred low dust masses are in a strong contrast with the relatively high gas accretion rates, suggesting global grain growth and/or an anomalous gas-to-dust ratio. Transition disks in the Cep OB2 region display strongly processed grains, suggesting that they are dominated by dust evolution and settling. Finally, the presence of rare but remarkable disks with strong accretion at old ages reveals that some very massive disks may still survive to grain growth, gravitational instabilities, and planet formation.

  13. Evaluate and characterize mechanisms controlling transport, fate, and effects of army smokes in the aerosol wind tunnel: Transport, transformations, fate, and terrestrial ecological effects of hexachloroethane obscurant smokes

    SciTech Connect (OSTI)

    Cataldo, D.A.; Ligotke, M.W.; Bolton, H. Jr.; Fellows, R.J.; Van Voris, P.; McVeety, B.D.; Li, Shu-mei W.; McFadden, K.M.

    1989-09-01T23:59:59.000Z

    The terrestrial transport, chemical fate, and ecological effects of hexachloroethane (HC) smoke were evaluated under controlled wind tunnel conditions. The primary objectives of this research program are to characterize and assess the impacts of smoke and obscurants on: (1) natural vegetation characteristic of US Army training sites in the United States; (2) physical and chemical properties of soils representative of these training sites; and (3) soil microbiological and invertebrate communities. Impacts and dose/responses were evaluated based on exposure scenarios, including exposure duration, exposure rate, and sequential cumulative dosing. Key to understanding the environmental impacts of HC smoke/obscurants is establishing the importance of environmental parameters such as relative humidity and wind speed on airborne aerosol characteristics and deposition to receptor surfaces. Direct and indirect biotic effects were evaluated using five plant species and two soil types. HC aerosols were generated in a controlled atmosphere wind tunnel by combustion of hexachloroethane mixtures prepared to simulate normal pot burn rates and conditions. The aerosol was characterized and used to expose plant, soil, and other test systems. Particle sizes of airborne HC ranged from 1.3 to 2.1 {mu}m mass median aerodynamic diameter (MMAD), and particle size was affected by relative humidity over a range of 20% to 85%. Air concentrations employed ranged from 130 to 680 mg/m{sup 3}, depending on exposure scenario. Chlorocarbon concentrations within smokes, deposition rates for plant and soil surfaces, and persistence were determined. The fate of principal inorganic species (Zn, Al, and Cl) in a range of soils was assessed.

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

    SciTech Connect (OSTI)

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

    2012-09-15T23:59:59.000Z

    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.

  15. Fragmentation and Evolution of Molecular Clouds. II: The Effect of Dust Heating

    E-Print Network [OSTI]

    Urban, Andrea; Evans, Neal J

    2009-01-01T23:59:59.000Z

    We investigate the effect of heating by luminosity sources in a simulation of clustered star formation. Our heating method involves a simplified continuum radiative transfer method that calculates the dust temperature. The gas temperature is set by the dust temperature. We present the results of four simulations, two simulations assume an isothermal equation of state and the two other simulations include dust heating. We investigate two mass regimes, i.e., 84 Msun and 671 Msun, using these two different energetics algorithms. The mass functions for the isothermal simulations and simulations which include dust heating are drastically different. In the isothermal simulation, we do not form any objects with masses above 1 Msun. However, the simulation with dust heating, while missing some of the low-mass objects, forms high-mass objects (~20 Msun) which have a distribution similar to the Salpeter IMF. The envelope density profiles around the stars formed in our simulation match observed values around isolated, l...

  16. Dust kinetic Alfvén waves and streaming instability in a non-Maxwellian magnetoplasma

    SciTech Connect (OSTI)

    Rubab, N.; Jaffer, G. [Department of Space Science, Institute of Space Technology (IST), Islamabad Expressway, Islamabad 44000 (Pakistan); Ali, S. [National Centre for Physics (NCP) at Quaid-i-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan)

    2014-06-15T23:59:59.000Z

    The dust kinetic Alfvén wave (DKAW) instability is studied in a uniform dusty magnetoplasma by incorporating the superthermality effects of the electrons and perpendicularly streaming ?-distributed ions. The dispersion relation of the DKAW instability is investigated in the low-?{sub d} Lorentzian plasma limit. The solutions are analyzed for various scenarios of dusty and dusty-free plasmas. It is shown that the presence of dust particles and the cross-field superthermal ions sensibly modify the dispersion characteristics of the low-frequency DKAW. The present results are only valid for a frequency regime well below the dust cyclotron frequency. Numerical calculations are carried out for the growth rates by taking different dust parameters into account. It is found that the nonthermality is more effective for the dust kinetic Alfvén waves in the perpendicular direction as compared to the parallel one. The relevance of the results to the low-?{sub d} regions of space and astrophysical plasmas is highlighted.

  17. On the Evolution of Dust Mineralogy, From Protoplanetary Disks to Planetary Systems

    E-Print Network [OSTI]

    Oliveira, Isa; Pontoppidan, Klaus M; van Dishoeck, Ewine F; Augereau, Jean-Charles; Merin, Bruno

    2011-01-01T23:59:59.000Z

    Mineralogical studies of silicate features emitted by dust grains in protoplanetary disks and Solar System bodies can shed light on the progress of planet formation. The significant fraction of crystalline material in comets, chondritic meteorites and interplanetary dust particles indicates a modification of the almost completely amorphous ISM dust from which they formed. The production of crystalline silicates thus must happen in protoplanetary disks, where dust evolves to build planets and planetesimals. Different scenarios have been proposed, but it is still unclear how and when this happens. This paper presents dust grain mineralogy of a complete sample of protoplanetary disks in the young Serpens cluster. These results are compared to those in the young Taurus region and to sources that have retained their protoplanetary disks in the older Upper Scorpius and Eta Chamaeleontis stellar clusters, using the same analysis technique for all samples. This comparison allows an investigation of the grain mineralo...

  18. On vapor shielding of dust grains of iron, molybdenum, and tungsten in fusion plasmas

    SciTech Connect (OSTI)

    Brown, B. T.; Smirnov, R. D., E-mail: rsmirnov@ucsd.edu; Krasheninnikov, S. I. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, 9500 Gilman Dr., La Jolla, California 92093-0411 (United States)] [Department of Mechanical and Aerospace Engineering, University of California, San Diego, 9500 Gilman Dr., La Jolla, California 92093-0411 (United States)

    2014-02-15T23:59:59.000Z

    The shielding effects of ablation cloud around a small dust grain composed of iron, molybdenum, or tungsten in fusion plasmas are considered. These include collisional dissipation of momentum flux of impinging plasma ions, heat transfer by secondary plasma created due to electron impact ionization of the ablated atoms, and radiative plasma power losses in the ablation cloud. The maximum radius, which limits applicability of existing dust-plasma interaction models neglecting the cloud shielding effects, for dust grains of the considered high-Z metals is calculated as function of plasma parameters. The thermal bifurcation triggered by thermionic electron emission from dust grains, observed for some of the considered materials, is analyzed. The results are compared with previous calculations for dust composed of low-Z fusion related materials, i.e., lithium, beryllium, and carbon.

  19. Preliminary analysis of graphite dust releasing behavior in accident for HTR

    SciTech Connect (OSTI)

    Peng, W.; Yang, X. Y.; Yu, S. Y.; Wang, J. [Inst. of Nuclear and New Energy Technology, Tsinghua Univ., Beijing100084 (China)

    2012-07-01T23:59:59.000Z

    The behavior of the graphite dust is important to the safety of High Temperature Gas-cooled Reactors. This study investigated the flow of graphite dust in helium mainstream. The analysis of the stresses acting on the graphite dust indicated that gas drag played the absolute leading role. Based on the understanding of the importance of gas drag, an experimental system is set up for the research of dust releasing behavior in accident. Air driven by centrifugal fan is used as the working fluid instead of helium because helium is expensive, easy to leak which make it difficult to seal. The graphite particles, with the size distribution same as in HTR, are added to the experiment loop. The graphite dust releasing behavior at the loss-of-coolant accident will be investigated by a sonic nozzle. (authors)

  20. APS/123-QED Influence of the ambipolar-to-free diffusion transition on dust particle charge in a

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    and the thermophoretic force [10, 11]. Dust particle charge is a key parameter in a complex plasma. It determines

  1. Matter-antimatter asymmetry and dark matter from torsion

    SciTech Connect (OSTI)

    Poplawski, Nikodem J. [Department of Physics, Indiana University, Swain Hall West, 727 East Third Street, Bloomington, Indiana 47405 (United States)

    2011-04-15T23:59:59.000Z

    We propose a simple scenario which explains the observed matter-antimatter imbalance and the origin of dark matter in the Universe. We use the Einstein-Cartan-Sciama-Kibble theory of gravity which naturally extends general relativity to include the intrinsic spin of matter. Spacetime torsion produced by spin generates, in the classical Dirac equation, the Hehl-Datta term which is cubic in spinor fields. We show that under a charge-conjugation transformation this term changes sign relative to the mass term. A classical Dirac spinor and its charge conjugate therefore satisfy different field equations. Fermions in the presence of torsion have higher energy levels than antifermions, which leads to their decay asymmetry. Such a difference is significant only at extremely high densities that existed in the very early Universe. We propose that this difference caused a mechanism, according to which heavy fermions existing in such a Universe and carrying the baryon number decayed mostly to normal matter, whereas their antiparticles decayed mostly to hidden antimatter which forms dark matter. The conserved total baryon number of the Universe remained zero.

  2. Nonlinear dust acoustic waves in inhomogeneous four-component dusty plasma with opposite charge polarity dust grains

    SciTech Connect (OSTI)

    El-Taibany, W. F. [Department of Physics, Faculty of Science, Damietta University, New Damietta P. O. 34517 (Egypt)] [Department of Physics, Faculty of Science, Damietta University, New Damietta P. O. 34517 (Egypt)

    2013-09-15T23:59:59.000Z

    The reductive perturbation technique is employed to investigate the propagation properties of nonlinear dust acoustic (DA) waves in a four-component inhomogeneous dusty plasma (4CIDP). The 4CIDP consists of both positive- and negative-charge dust grains, characterized by different mass, temperature, and density, in addition to a background of Maxwellian electrons and ions. The inhomogeneity caused by nonuniform equilibrium values of particle densities, fluid velocities, and electrostatic potential leads to a significant modification to the nature of nonlinear DA solitary waves. It is found that this model reveals two DA wave velocities, one slow, ?{sub s}, and the other is fast, ?{sub f}. The nonlinear wave evolution is governed by a modified Kortweg-de Vries equation, whose coefficients are space dependent. Both the two soliton types; compressive and rarefactive are allowed corresponding to ?{sub s}. However, only compressive soliton is created corresponding to ?{sub f}. The numerical investigations illustrate the dependence of the soliton amplitude, width, and velocity on the plasma inhomogeneities in each case. The relevance of these theoretical results with 4CIDPs observed in a multi-component plasma configurations in the polar mesosphere is discussed.

  3. PROPERTIES OF NEWLY FORMED DUST GRAINS IN THE LUMINOUS TYPE IIn SUPERNOVA 2010jl

    SciTech Connect (OSTI)

    Maeda, K.; Nozawa, T.; Folatelli, G.; Moriya, T. J.; Nomoto, K.; Bersten, M.; Quimby, R. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Sahu, D. K.; Anupama, G. C. [Indian Institute of Astrophysics, Koramangala, Bangalore 560 034 (India); Minowa, Y.; Pyo, T.-S. [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720 (United States); Motohara, K.; Kitagawa, Y. [Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Ueno, I.; Kawabata, K. S.; Yamanaka, M. [Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Kozasa, T. [Department of Cosmosciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan); Iye, M., E-mail: keiichi.maeda@ipmu.jp [National Astronomical Observatory, Mitaka, Tokyo (Japan)

    2013-10-10T23:59:59.000Z

    Supernovae (SNe) have been proposed to be the main production sites of dust grains in the universe. However, our knowledge of their importance to dust production is limited by observationally poor constraints on the nature and amount of dust particles produced by individual SNe. In this paper, we present a spectrum covering optical through near-Infrared (NIR) light of the luminous Type IIn supernova 2010jl around one and a half years after the explosion. This unique data set reveals multiple signatures of newly formed dust particles. The NIR portion of the spectrum provides a rare example where thermal emission from newly formed hot dust grains is clearly detected. We determine the main population of the dust species to be carbon grains at a temperature of ?1350-1450 K at this epoch. The mass of the dust grains is derived to be ?(7.5-8.5) × 10{sup –4} M{sub ?}. Hydrogen emission lines show wavelength-dependent absorption, which provides a good estimate of the typical size of the newly formed dust grains (?< 0.1 ?m, and most likely ?< 0.01 ?m). We believe the dust grains were formed in a dense cooling shell as a result of a strong SN-circumstellar media (CSM) interaction. The dust grains occupy ?10% of the emitting volume, suggesting an inhomogeneous, clumpy structure. The average CSM density must be ?> 3 × 10{sup 7} cm{sup –3}, corresponding to a mass loss rate of ?> 0.02 M{sub ?} yr{sup –1} (for a mass loss wind velocity of ?100 km s{sup –1}). This strongly supports a scenario in which SN 2010jl and probably other luminous SNe IIn are powered by strong interactions within very dense CSM, perhaps created by Luminous-Blue-Variable-like eruptions within the last century before the explosion.

  4. Metal-Exchanged Clay and Zeolite Additives as Smoke Suppressants and Fire Retardants for

    E-Print Network [OSTI]

    Pike, Robert D.

    Metal-Exchanged Clay and Zeolite Additives as Smoke Suppressants and Fire Retardants for Poly studies showed that various metal- exchanged clays and zeolites containing only 3­4% of Cu(II), Cu(I), Zn blends of the clays, and the effectiveness of the additives was usually improved considerably by heat

  5. Cent Eur J Public Health 2011; 19 (1): 5459 Smoking practiceS in Jordanian people

    E-Print Network [OSTI]

    that causes the death of about half of its regular users (3). On the other hand, a decline in smoking rate was recently documented in many countries such as the United States ofAmerica, Finland,Australia and Canada (4 of death globally, resulting in nearly five million deaths a year (2). Tobacco is the only legal product

  6. The Factors of Chronic Kidney Disease: Diabetes, Hypertension, Smoking, Drinking, Betelnut Chewing

    E-Print Network [OSTI]

    Chen, Chaur-Chin

    The Factors of Chronic Kidney Disease: Diabetes, Hypertension, Smoking, Drinking, Betelnut Chewing CKD 75 CKD Abstract The risk factors of Chronic Kidney Disease (CKD), including diabetes risk factors in a population-based cohort. Compared with single risk factors, diabetes (odds ratio 1

  7. apprenticeship site-based smoking: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    apprenticeship site-based smoking First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Software Engineering...

  8. Financial incentives for smoking cessation in pregnancy: a single arm intervention study assessing cessation and gaming

    E-Print Network [OSTI]

    Ierfino, Diana; Mantzari, Eleni; Hirst, Julie; Jones, Tina; Aveyard, Paul; Marteau, Theresa M.

    2015-01-01T23:59:59.000Z

    ., Hadders-Algra, M. & Neeleman, J. (2003) Effect of antenatal exposure 18 to maternal smoking on behavioural problems and academic achievement in 19 childhood: prospective evidence from a Dutch birth cohort, Early Human 20 Development, 75, 21-33. 21 2...

  9. Introduction Luminance and Chrominance High Frequency Content References Smoke Detection in Stationary Video Using

    E-Print Network [OSTI]

    Knaust, Helmut

    Introduction Luminance and Chrominance High Frequency Content References Smoke Detection at El Paso El Paso TX 79968-0514 hknaust@utep.edu January 6, 2012 #12;Introduction Luminance and Chrominance High Frequency Content References The Problem The Problem: VIDEO: #12;Introduction Luminance

  10. SMOKE AND CFD VISUALIZATION OF THE FLOW AFTER AN EMC SCREEN IN A SUBRACK MODEL

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    SMOKE AND CFD VISUALIZATION OF THE FLOW AFTER AN EMC SCREEN IN A SUBRACK MODEL Raúl Antón1, 2, 3 analysed are the velocity, the EMC screen porosity and the subrack geometry. The technique used pattern after the screen. KEYWORDS: RNG k-, perforated plate, porosity, EMC screen, subrack, flow pattern

  11. CALCULATIONS OF FIRE SMOKE BEHAVIOUR IN LONG RAIL TUNNELS S. DARON, E. RUFFIN

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    2000-13 CALCULATIONS OF FIRE SMOKE BEHAVIOUR IN LONG RAIL TUNNELS S. DAÃ?RON, E. RUFFIN INERIS Parc in complex underground networks, we want to implement a coupling between a ID ventilation code and a CFD model or a zone model. The project consists in 3 main steps: the development of a ID ventilation code

  12. Slaw.........................$1.50 Your choice of house smoked meat and signature sauce, topped with

    E-Print Network [OSTI]

    Washington at Seattle, University of

    , Minutemaid Lemonade and Dasani bottled water HOUSE SPECIALS 1/2 LB SMOKED PORK RIB TIPS..................$ 5.........................$ 5.95 Choice of meat and sauce layered with slow-cooked BBQ beans and slaw .........Ranch Potato Salad $1.50 Mac & Cheese..............$2.00 ......Slow-cooked BBQ Beans $1.50 $ 5.95 $ 6.00 $ 2.00 $ 4

  13. Plutonium-238 observations as a test of modeled transport and surface deposition of meteoric smoke particles

    E-Print Network [OSTI]

    Chipperfield, Martyn

    Plutonium-238 observations as a test of modeled transport and surface deposition of meteoric smoke chemistry-climate model (CCM) to simulate the transport and deposition of plutonium- 238 oxide nanoparticles. P. Chipperfield, and J. M. C. Plane (2013), Plutonium-238 observations as a test of modeled

  14. Earth's Energy Out of Balance: The Smoking Gun for Global Warming April, 2005

    E-Print Network [OSTI]

    Hansen, James E.

    evaluated the energy imbalance using precise measurements of ocean temperature obtained by ocean floatsEarth's Energy Out of Balance: The Smoking Gun for Global Warming April, 2005 Scientists at Columbia University, NASA, and the Department of Energy have found that the Earth is out of energy balance

  15. Energy conservation in electrostatic fabric filtration of industrial dust

    SciTech Connect (OSTI)

    Ariman, T.

    1981-12-01T23:59:59.000Z

    Conservation in energy consumption in industrial fabric filtration systems has become very important due to the substantial increase in energy costs. Recently, an external electric field was utilized in the industrial dust control by fabric filters with very promising initial results. A substantial decrease in the pressure drop and an increase in collection efficiency were observed. The detailed outcome of the experimental research program in electrostatic fabric filtration was presented. The results show that pressure drop decreases substantially with the increased electrostatic field strength for all relevant parameters. Furthermore, the data of the experimental program was utilized to develop a semi-empirical model for the determination of the pressure drop and to establish an Energy-Optimized Design Criteria.

  16. Singularity avoidance in quantum-inspired inhomogeneous dust collapse

    E-Print Network [OSTI]

    Yue Liu; Daniele Malafarina; Leonardo Modesto; Cosimo Bambi

    2014-08-17T23:59:59.000Z

    In a previous paper, some of us studied general relativistic homogeneous gravitational collapses for dust and radiation, in which the density profile was replaced by an effective density justified by some quantum gravity models. It was found that the effective density introduces an effective pressure that becomes negative and dominant in the strong-field regime. With this set-up, the central singularity is replaced by a bounce, after which the cloud starts expanding. Motivated by the fact that in the classical case homogeneous and inhomogeneous collapse models have different properties, here we extend our previous work to the inhomogeneous case. As in the quantum-inspired homogeneous collapse model, the classical central singularity is replaced by a bounce, but the inhomogeneities strongly affect the structure of the bounce curve and of the trapped region.

  17. Generator, mechanical, smoke: For dual-purpose unit, XM56, Yuma Proving Ground, Yuma, Arizona

    SciTech Connect (OSTI)

    Driver, C.J.; Ligotke, M.W.; Moore, E.B. Jr. (Pacific Northwest Lab., Richland, WA (United States)); Bowers, J.F. (Dugway Proving Ground, UT (United States))

    1991-10-01T23:59:59.000Z

    The US Army Chemical Research, Development and Engineering Center (CRDEC) is planning to perform a field test of the XM56 smoke generator at the US Army Yuma Proving Ground (YPG), Arizona. The XM56, enabling the use of fog oil in combination with other materials, such as graphite flakes, is part of an effort to improve the efficiency of smoke generation and to extend the effectiveness of the resulting obscurant cloud to include the infrared spectrum. The plan field operation includes a road test and concurrent smoke- generation trials. Three M1037 vehicles with operation XM56 generators will be road-tested for 100 h. Smoke will be generated for 30 min from a single stationary XM56 four times during the road test, resulting in a total of 120 min of smoke generation. The total aerial release of obscurant materials during this test is expected to be 556 kg (1,220 lb) of fog oil and 547 kg (1,200 lb) of graphite flakes. This environmental assessment has evaluated the consequences of the proposed action. Air concentrations and surface deposition levels were estimated using an atmospheric dispersion model. Degradation of fog oil and incorporation of graphite in the soil column will limit the residual impacts of the planned action. No significant impacts to air, water, and soil quality are anticipated. risks to the environment posed by the proposed action were determined to be minimal or below levels previously found to pose measurable impacts. Cultural resources are present on YPG and have been identified in adjacent areas; therefore, off-road activities should be preceded by a cultural resource survey. A Finding of No Significant Impact is recommended. 61 refs., 1 fig.

  18. Polycyclic aromatic hydrocarbons in fresh and smoked fish samples from three Nigerian cities

    SciTech Connect (OSTI)

    Akpan, V.; Lodovici, M.; Dolara, P. (Dept. of Pharmacology and Toxicology, Florence (Italy))

    1994-08-01T23:59:59.000Z

    Nigeria is a major producer of crude oil in sub-Saharan Africa. In-shore and off-shore wells are located in richly watered creeks in the southern part of the country. Although published data on environmental impact assessment of the petroleum industry in Nigeria are lacking, there is a growing concern about the possible contamination of estuarine and coastal waters and of marine species by polycyclic aromatic hydrocarbon (PAHs). PAHs are ubiquitous priority pollutants that occur naturally in crude oil, automobile exhaust emissions and smoke condensates from incomplete combustion of carbonaceous materials. PAHs with high molecular weight are less readily biodegraded by indigenous microorganisms in some regions, and given their marked hydrophobic characteristics, may persist in the aqueous environment, thus contaminating the food chain by bioaccumulating in aquatic species like fish and mussels. Major Nigerian oil wells are located in the vicinity of breeding and harvesting sites serving the fresh-water fishing industry. Large hauls of fresh fish are normally consumed cooked in soups or smoke cured in handcrafted traditional ovens using freshly cut red mangrove (Rhizophora racemosa) wood as fuel. Though smoke curing is economical and may ensure longer conservation of fish, it undoubtedly increases the burden of PAHs in finished products as a result of partial charring and from smoke condensates or mangroves that also contain PAHs in measurable quantities as reported by Asita et al. (1991). Apart from PAHs analyzed by Emerole (1980) in smoked food samples from Ibadan using simple analytical methods, those from industrial and other anthropogenic sources have rarely been analyzed in Nigeria. We tried therefore to update the data and address this discrepancy. 14 refs., 4 figs., 2 tabs.

  19. PHOTOEVAPORATION OF CIRCUMSTELLAR DISKS REVISITED: THE DUST-FREE CASE

    SciTech Connect (OSTI)

    Tanaka, Kei E. I.; Omukai, Kazuyuki [Astronomical Institute, Tohoku University, Sendai 980-8578 (Japan); Nakamoto, Taishi, E-mail: ktanaka@astr.tohoku.ac.jp [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo 152-8551 (Japan)

    2013-08-20T23:59:59.000Z

    Photoevaporation by stellar ionizing radiation is believed to play an important role in the dispersal of disks around young stars. The mass-loss model for dust-free disks developed by Hollenbach et al. is currently regarded as the conventional one and has been used in a wide variety of studies. However, the rate in this model was derived using the crude so-called 1+1D approximation of ionizing radiation transfer, which assumes that diffuse radiation propagates in a direction vertical to the disk. In this study, we revisit the photoevaporation of dust-free disks by solving the two-dimensional axisymmetric radiative transfer for steady-state disks. Unlike that solved by the conventional model, we determine that direct stellar radiation is more important than the diffuse field at the disk surface. The radial density distribution at the ionization boundary is represented by a single power law with index -3/2 in contrast to the conventional double power law. For this distribution, the photoevaporation rate from the entire disk can be written as a function of the ionizing photon emissivity {Phi}{sub EUV} from the central star and the disk outer radius r{sub d} as follows: M-dot{sub PE} = 5.4 x 10{sup -5} ({Phi}{sub EUV}/10{sup 49} s{sup -1}){sup 1/2} (r{sub d}/1000 AU){sup 1/2} M{sub Sun} yr{sup -1}. This new rate depends on the outer disk radius rather than on the gravitational radius as in the conventional model, because of the enhanced contribution to the mass loss from the outer disk annuli. In addition, we discuss its applications to present-day as well as primordial star formation.

  20. A SPITZER SURVEY OF PROTOPLANETARY DISK DUST IN THE YOUNG SERPENS CLOUD: HOW DO DUST CHARACTERISTICS EVOLVE WITH TIME?

    SciTech Connect (OSTI)

    Oliveira, Isa; Van Dishoeck, Ewine F.; Lahuis, Fred [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Pontoppidan, Klaus M. [California Institute of Technology, Division for Geological and Planetary Sciences, MS 150-21, Pasadena, CA 91125 (United States); MerIn, Bruno [Herschel Science Center, European Space Agency (ESA), P.O. Box 78, 28691 Villanueva de la Canada (Madrid) (Spain); Geers, Vincent C. [University of Toronto, 50 St. George St., Toronto, ON M5R 2W9 (Canada); Joergensen, Jes K. [Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Oester Voldgade 5-7, DK-1350 Copenhagen (Denmark); Olofsson, Johan; Augereau, Jean-Charles [Laboratoire d'Astrophysique de Grenoble, Universite Joseph Fourier, CNRS, UMR 5571, Grenoble (France); Brown, Joanna M., E-mail: oliveira@strw.leidenuniv.n [Max-Planck Institut fuer Extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching (Germany)

    2010-05-01T23:59:59.000Z

    We present Spitzer InfraRed Spectrograph (IRS) mid-infrared (5-35 {mu}m) spectra of a complete flux-limited sample ({>=}3 mJy at 8 {mu}m) of young stellar object (YSO) candidates selected on the basis of their infrared colors in the Serpens Molecular Cloud. Spectra of 147 sources are presented and classified. Background stars (with slope consistent with a reddened stellar spectrum and silicate features in absorption), galaxies (with redshifted polycyclic aromatic hydrocarbon (PAH) features), and a planetary nebula (with high ionization lines) amount to 22% of contamination in this sample, leaving 115 true YSOs. Sources with rising spectra and ice absorption features, classified as embedded Stage I protostars, amount to 18% of the sample. The remaining 82% (94) of the disk sources are analyzed in terms of spectral energy distribution shapes, PAHs, and silicate features. The presence, strength, and shape of these silicate features are used to infer disk properties for these systems. About 8% of the disks have 30/13 {mu}m flux ratios consistent with cold disks with inner holes or gaps, and 3% of the disks show PAH emission. Comparison with models indicates that dust grains in the surface of these disks have sizes of at least a few {mu}m. The 20 {mu}m silicate feature is sometimes seen in the absence of the 10 {mu}m feature, which may be indicative of very small holes in these disks. No significant difference is found in the distribution of silicate feature shapes and strengths between sources in clusters and in the field. Moreover, the results in Serpens are compared with other well-studied samples: the c2d IRS sample distributed over five clouds and a large sample of disks in the Taurus star-forming region. The remarkably similar distributions of silicate feature characteristics in samples with different environment and median ages-if significant-imply that the dust population in the disk surface results from an equilibrium between dust growth and destructive collision processes that are maintained over a few million years for any YSO population irrespective of environment.

  1. Dynamical dark matter. II. An explicit model

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Dienes, Keith R.; Thomas, Brooks

    2012-04-01T23:59:59.000Z

    In a recent paper [K. R. Dienes and B. Thomas, Phys. Rev. D 85, 083523 (2012).], we introduced “dynamical dark matter,” a new framework for dark-matter physics, and outlined its underlying theoretical principles and phenomenological possibilities. Unlike most traditional approaches to the dark-matter problem which hypothesize the existence of one or more stable dark-matter particles, our dynamical dark-matter framework is characterized by the fact that the requirement of stability is replaced by a delicate balancing between cosmological abundances and lifetimes across a vast ensemble of individual dark-matter components. This setup therefore collectively produces a time-varying cosmological dark-matter abundance, and the different dark-matter components can interact and decay throughout the current epoch. While the goal of our previous paper was to introduce the broad theoretical aspects of this framework, the purpose of the current paper is to provide an explicit model of dynamical dark matter and demonstrate that this model satisfies all collider, astrophysical, and cosmological constraints. The results of this paper therefore constitute an “existence proof” of the phenomenological viability of our overall dynamical dark-matter framework, and demonstrate that dynamical dark matter is indeed a viable alternative to the traditional paradigm of dark-matter physics. Dynamical dark matter must therefore be considered alongside other approaches to the dark-matter problem, particularly in scenarios involving large extra dimensions or string theory in which there exist large numbers of particles which are neutral under standard-model symmetries.

  2. DUST EMISSION FROM EVOLVED AND UNEVOLVED H II REGIONS IN THE LARGE MAGELLANIC CLOUD

    SciTech Connect (OSTI)

    Slater, C. T.; Oey, M. S. [Astronomy Department, University of Michigan, Ann Arbor, MI 48109 (United States); Li, A. [Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211 (United States); Bernard, J.-Ph.; Paradis, D. [Universit de Toulouse, UPS-OMP, IRAP, Toulouse (France); Churchwell, E. [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States); Gordon, K. D.; Lawton, B.; Meixner, M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Indebetouw, R. [Department of Astronomy, University of Virginia, P.O. Box 3818, Charlottesville, VA 22903 (United States); Reach, W.T. [Universities Space Research Association, Stratospheric Observatory for Infrared Astronomy, NASA Ames Research Center, MS 211-3, Moffett Field, CA 94035 (United States)

    2011-05-10T23:59:59.000Z

    We present a study of the dust properties of 12 classical and superbubble H II regions in the Large Magellanic Cloud. We use infrared photometry from Spitzer (8, 24, 70, and 160 {mu} m bands), obtained as part of the Surveying the Agents of a Galaxy's Evolution (SAGE) program, along with archival spectroscopic classifications of the ionizing stars to examine the role of stellar sources on dust heating and processing. Our infrared observations show surprisingly little correlation between the emission properties of the dust and the effective temperatures or bolometric magnitudes of stars in the H II regions, suggesting that the H II region evolutionary timescale is not on the order of the dust processing timescale. We find that the infrared emission of superbubbles and classical H II regions shows little differentiation between the two classes, despite the significant differences in age and morphology. We do detect a correlation of the 24 {mu} m emission from hot dust with the ratio of 70-160 {mu} m flux. This correlation can be modeled as a trend in the temperature of a minority hot dust component, while a majority of the dust remains significantly cooler.

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

    SciTech Connect (OSTI)

    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

    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.

  4. Polychlorinated biphenyls in house dust and yard soil near a Superfund site

    SciTech Connect (OSTI)

    Vorhees, D.J.; Altshul, L.M. [Harvard School of Public Health, Boston, MA (United States)] [Harvard School of Public Health, Boston, MA (United States); Cullen, A.C. [Harvard School of Public Health, Boston, MA (United States)] [Harvard School of Public Health, Boston, MA (United States); [Univ. of Washington, Seattle, WA (United States)

    1999-07-01T23:59:59.000Z

    Polychlorinated biphenyls (PCBs) were measured in house dust and yard soil at 34 homes surrounding New Bedford Harbor during dredging of highly contaminated harbor sediments. PCBs can volatilize from sediments and seawater and subsequently deposit on surrounding soil, resulting in potential exposures for nearby residents. House dust was collected from carpet, while yard soil was collected from the main entryway to evaluate whether PCBs might be tracked indoors. All samples were analyzed for 65 PCB congeners to evaluate the relative importance of the harbor and indoor sources for human exposure. PCB concentrations in house dust were about 10 times higher than yard soil concentrations, although similar congener patterns were detected in these two media. Yard soil concentrations in neighborhoods closest to the harbor were significantly higher than those in comparison neighborhoods, while house dust concentrations did not different significantly between these two locales, PCB concentrations in house dust were correlated with those in indoor air, but house dust and yard soil concentrations were not correlated, suggesting that track-in may not be the only source of PCBs in house dust.

  5. Effect of confining wall potential on charged collimated dust beam in low-pressure plasma

    SciTech Connect (OSTI)

    Kausik, S. S.; Kakati, B.; Saikia, B. K. [Centre of Plasma Physics, Institute for Plasma Research, Sonapur 782 402 (India)] [Centre of Plasma Physics, Institute for Plasma Research, Sonapur 782 402 (India)

    2013-05-15T23:59:59.000Z

    The effect of confining wall potential on charged collimated dust beam in low-pressure plasma has been studied in a dusty plasma experimental setup by applying electrostatic field to each channel of a multicusp magnetic cage. Argon plasma is produced by hot cathode discharge method at a pressure of 5×10{sup ?4} millibars and is confined by a full line cusped magnetic field confinement system. Silver dust grains are produced by gas-evaporation technique and move upward in the form of a collimated dust beam due to differential pressure maintained between the dust and plasma chambers. The charged grains in the beam after coming out from the plasma column enter into the diagnostic chamber and are deflected by a dc field applied across a pair of deflector plates at different confining potentials. Both from the amount of deflection and the floating potential, the number of charges collected by the dust grains is calculated. Furthermore, the collimated dust beam strikes the Faraday cup, which is placed above the deflector plates, and the current (?pA) so produced is measured by an electrometer at different confining potentials. The experimental results demonstrate the significant effect of confining wall potential on charging of dust grains.

  6. A Search for Extraplanar Dust in Nearby Edge-On Spirals

    E-Print Network [OSTI]

    J. Christopher Howk; Blair D. Savage

    1999-02-04T23:59:59.000Z

    We present high resolution BV images of 12 edge-on spiral galaxies observed with the WIYN 3.5-m telescope. These images were obtained to search for extraplanar (|z| > 0.4 kpc) absorbing dust structures similar to those previously found in NGC 891 (Howk & Savage 1997). Our imaged galaxies include a sample of seven massive L_*-like spiral galaxies within D 87 deg from the plane of the sky. We find that five of these seven systems show extraplanar dust, visible as highly-structured absorbing clouds against the background stellar light of the galaxies. The more prominent structures are estimated to have associated gas masses >10^5 M_sun; the implied potential energies are > 10^(52) ergs. All of the galaxies in our sample that show detectable halpha emission at large z also show extraplanar dust structures. None of those galaxies for which extraplanar halpha searches were negative show evidence for extensive high-z dust. The existence of extraplanar dust is a common property of massive spiral galaxies. We discuss several mechanisms for shaping the observed dust features, emphasizing the possibility that these dusty clouds represent the dense phase of a multiphase medium at high-z in spiral galaxies. The correlation between high-z dust and extraplanar Halpha emission may simply suggest that both trace the high-z interstellar medium in its various forms (or phases), the existence of which may ultimately be driven by vigorous star formation in the underlying disk. (Abstract abridged)

  7. Development of a Low-Cost Particulate Matter Monitor

    E-Print Network [OSTI]

    White, Richard M.

    2010-01-01T23:59:59.000Z

    response to fresh diesel exhaust Generation of dieselduring and after generation of ETS and diesel exhaust inof PM generation of cigarette smoke and diesel exhaust

  8. Phi Meson in Dense Matter

    E-Print Network [OSTI]

    Ko, Che Ming; Levai, P.; Qiu, X. J.; Li, C. T.

    1992-01-01T23:59:59.000Z

    PHYSICAL REVIEW C VOLUME 45, NUMBER 3 MARCH 1992 Phi meson in dense matter C. M. Ko, P. Levai, * and X. J. Qiu Cyclotron Institute and Physics Department, Texas A &M University, College Station, Texas 77843 C. T. Li Physics Department, National... Taiwan University, Taipei, Taiwan 10764, China {Received 3 September 1991) The effect of the kaon loop correction to the property of a phi meson in dense matter is studied in the vector dominance model. Using the density-dependent kaon effective mass...

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

    SciTech Connect (OSTI)

    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

    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.

  10. Impact of Long-Range Dust Transport on Northern California in Spring 2002

    SciTech Connect (OSTI)

    Cameron-Smith, P; Bergmann, D; Chuang, C; Bench, G; Cliff, S; Kelly, P; Perry, K; VanCuren, T

    2005-02-10T23:59:59.000Z

    It has been well documented that spectacular dust storms in Asia (e.g. the events in 1998 and 2001) can affect the USA through long-range transport of dust across the Pacific. However, our observations and modeling show that the majority of dust at sites in Lassen National Park and Trinity Alps (Northern California) in spring 2002 (a year with no spectacular Asian dust events) is still from long-range intercontinental transport across the Pacific. We implemented the interactive dust emission algorithm of Ginoux et al. (2004) into the LLNL 3-D global atmospheric chemistry and aerosol transport model (IMPACT), then ran the model using a separate tracer for each dust emission region, using hi-resolution (1 x 1 degree) meteorological data from the NASA GMAO GEOS-3 assimilation system for 2001 and 2002. We also experimentally analyzed size- and time-resolved aerosol samples at Lassen National Park and Trinity Alps in the spring of 2002, which were taken as part of NOAA's ITCT 2k2 measurement campaign. The model-predicted time-series of soil dust over Northern California agrees remarkably well with our measurements, with a strong temporal correlation between the observations and intercontinental transport of dust across the Pacific in the model. Hence, we conclude that the majority of dust we sampled in Northern California in spring 2002, with aerodynamic diameters of 0.56-5 microns, is from long-range intercontinental transport across the Pacific. The strong correlations also strongly validate atmospheric transport in the IMPACT model over the Northern Pacific in spring.

  11. The dusty MOCASSIN: fully self-consistent 3D photoionisation and dust radiative transfer models

    E-Print Network [OSTI]

    B. Ercolano; M. J. Barlow; P. J. Storey

    2005-07-02T23:59:59.000Z

    We present the first 3D Monte Carlo (MC) photoionisation code to include a fully self-consistent treatment of dust radiative transfer (RT) within a photoionised region. This is the latest development (Version 2.0) of the gas-only photoionisation code MOCASSIN (Ercolano et al., 2003a), and employs a stochastic approach to the transport of radiation, allowing both the primary and secondary components of the radiation field to be treated self-consistently, whilst accounting for the scattering of radiation by dust grains mixed with the gas, as well as the absorption and emission of radiation by both the gas and the dust components. A set of rigorous benchmark tests have been carried out for dust-only spherically symmetric geometries and 2D disk configurations. MOCASSIN's results are found to be in agreement with those obtained by well established dust-only RT codes that employ various approaches to the solution of the RT problem. A model of the dust and of the photoionised gas components of the planetary nebula (PN) NGC 3918 is also presented as a means of testing the correct functioning of the RT procedures in a case where both gas and dust opacities are present. The two components are coupled via the heating of dust grains by the absorption of both UV continuum photons and resonance line photons emitted by the gas. The MOCASSIN results show agreement with those of a 1D dust and gas model of this nebula published previously, showing the reliability of the new code, which can be applied to a variety of astrophysical environments.

  12. Dust Formation Events in Colliding Winds: an application to eta Car

    E-Print Network [OSTI]

    D. Falceta-Goncalves; V. Jatenco-Pereira; Z. Abraham

    2002-10-29T23:59:59.000Z

    Recent IR observations indicate that many massive binary systems present dust formation episodes, in regions close to the stars, during the periastron passage. These systems are known to be high-energy sources, and it is believed that wind collisions are the origin of the emission. In this work we show that wind collisions not only increase the X-ray emission but also allow dust formation. As an application we study eta Car, which presents, near periastron, an increase in the X-ray emission followed by a sudden decrease that lasts for about a month. We reproduce this feature calculating the optical depth due to dust formation along the orbital period.

  13. Solitary dust sound waves in a plasma with two-temperature ions and distributed grain size

    SciTech Connect (OSTI)

    Prudskikh, V. V. [Southern Federal University, Research Institute of Physics (Russian Federation)

    2009-01-15T23:59:59.000Z

    The propagation of weakly nonlinear dust sound waves in a dusty plasma containing two different-temperature ion species is explored. The nonlinear equations describing both the quadratic and cubic plasma nonlinearities are derived. It is shown that the properties of dust sound waves depend substantially on the grain size distribution. In particular, for solitary dust sound waves with a positive potential to exist in a plasma with distributed grain size, it is necessary that the difference between the temperatures of two ion species be larger than that in the case of equal-size grains.

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

    SciTech Connect (OSTI)

    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

    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.

  15. Electrical time resolved metrology of dust particles growing in low pressure cold plasmas

    SciTech Connect (OSTI)

    Wattieaux, Gaeetan [PRISME, Orleans University, 12 rue de Blois BP 6744, 45067 Orleans cedex 2 (France); Mezeghrane, Abdelaziz [LPCQ, Mouloud Mammeri University, Tizi-Ouzou (Algeria); Boufendi, Laiefa [GREMI, Orleans University, 14 rue d'Issoudun BP 6744, 45067 Orleans cedex 2 (France)

    2011-09-15T23:59:59.000Z

    The electrical parameters of a capacitively coupled radiofrequency (CCRF) discharge change significantly when dust arises in the discharge. This work demonstrates the ability to follow in real time the evolution of the size and of the concentration of dust particles forming in a CCRF discharge from the variation of the electron density and of the self-bias voltage of the active electrode. According to experimental findings, it appears that the variation of this self-bias voltage depends on the surface of the dust particles. This trend is confirmed by an analytical modelling considering the low frequency behaviour of the phenomenon.

  16. Grain quality impacts of prohibiting recombination recirculation dust at export grain elevators

    E-Print Network [OSTI]

    Spillmann, Daryl Drew

    1992-01-01T23:59:59.000Z

    such as those where grain moves from one belt conveyor to another, one auger to another, into and out of a bucket elevator, or into and out of storage bins. Typically, a cloud of dust is created at each transfer point. Since this dust cloud.... Dust ventilation is energy intensive and can account for a large portion (one-third to one-half) of an elevator's electrical energy cost (Whitelock, 1991). National Grain and Feed Association (1981) and National Materials Advisory Board (1982) have...

  17. A New Facility for Studying Shock Wave Passage over Dust Layers

    E-Print Network [OSTI]

    Marks, Brandon

    2013-05-30T23:59:59.000Z

    to be easily removable and is secured by six, T-handle, 1/2?-13 screws. The T-handles are threaded through 1/2-inch stainless steel plate which is secured to the shock tube window weld pads. The T-handles only need to be hand-tight to provide enough clamping...-490. 37 APPENDIX A TEST SECTION ENGINEERING DRAWINGS Figure A1. Dust pan clamping plate drawing. This plate is fixed to the window weld pads and secures the T-handles that clamp the dust pan into place. 38 Figure A2. Dust pan drawing...

  18. Discovery of a large dust disk around the nearby star AU Microscopium

    E-Print Network [OSTI]

    Paul Kalas; Michael C. Liu; Brenda C. Matthews

    2004-03-05T23:59:59.000Z

    We present the discovery of a circumstellar dust disk surrounding AU Microscopium (AU Mic, GJ 803, HD 197481). This young M star at 10 parsec has the same age and origin as beta Pictoris, another nearby star surrounded by a dust disk. The AU Mic disk is detected between 50 AU and 210 AU radius, a region where dust lifetimes exceed the present stellar age. Thus, AU Mic is the nearest star where we directly observe the solid material required for planet formation. Since 85% of stars are M-type, the AU Mic disk provides new clues on how the majority of planetary systems might form and evolve.

  19. Note: Electrostatic detection of stainless steel dust particles for fusion applications

    SciTech Connect (OSTI)

    Landy, P. [Mechanical and Aerospace Engineering Department, Cornell University, Ithaca, New York 14853 (United States)] [Mechanical and Aerospace Engineering Department, Cornell University, Ithaca, New York 14853 (United States); Skinner, C. H.; Schneider, H. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2014-03-15T23:59:59.000Z

    Dust accumulation inside next-step fusion devices poses a significant safety concern and dust diagnostics will be needed to assure safe operations. An electrostatic dust detection device has been successfully demonstrated in the National Spherical Torus Experiment, Tore Supra, and the Large Helical Device, and the detector's response to carbon particles was previously characterized in laboratory experiments. This paper presents laboratory results showing that detection of stainless steel particles at levels as low as several ?g/cm{sup 2} is also possible.

  20. 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]

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

    2013-01-01T23:59:59.000Z

    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...