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1

Characterization of jovian plasma embedded dust particles  

E-Print Network [OSTI]

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.

Amara L. Graps

2006-09-12T23:59:59.000Z

2

Characterisation of Dust Particles Trapped in Silica Aerogels.  

E-Print Network [OSTI]

?? This thesis involves the study of dust particles trapped in silica aerogel for fusion dust diagnostics purpose. The low velocity impact experiments are done… (more)

Liu, Bing

2011-01-01T23:59:59.000Z

3

A model to predict the breathing zone concentrations of particles emitted from Jonathan Thornburg,*a  

E-Print Network [OSTI]

Triangle Park, NC, 27709, USA. E-mail: jwt@rti.org b Environmental Quality Management Inc., 1800 Carillon as they perform a scripted activity, such as raking a specified area of soil, while wearing appropriate sample rate, tracked particle transport to the breathing zone, and calculated the breathing zone concentration

Ahmad, Sajjad

4

Transport of dust particles in inductively coupled discharges  

SciTech Connect (OSTI)

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.

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

5

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

E-Print Network [OSTI]

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

Collett Jr., Jeffrey L.

6

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

E-Print Network [OSTI]

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...

Bekki, Kenji

2015-01-01T23:59:59.000Z

7

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

SciTech Connect (OSTI)

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.

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

2004-11-01T23:59:59.000Z

8

Coulomb interactions between dust particles in plasma etching reactors  

SciTech Connect (OSTI)

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.

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

9

Direct Observation of Completely Processed Calcium Carbonate Dust Particles  

SciTech Connect (OSTI)

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.

Laskin, Alexander; Iedema, Martin J.; Ichkovich, Aviad; Graber, Ellen R.; Taraniuk, Ilya; Rudich, Yinon

2005-05-27T23:59:59.000Z

10

Imaging of high-speed dust particle trajectories on NSTX  

SciTech Connect (OSTI)

Imaging of high-speed incandescent dust particle trajectories in a tokamak plasma has been accomplished on NSTX using up to three high-speed cameras each viewing the same plasma volume from different locations and operating at speeds up to 68 000 frames/s with exposure times varying from 2 to 300 {mu}s. The dynamics of the dust trajectories can be quite complex exhibiting a large variation in both speed (10-200 m/s) and direction. Simulations of these trajectories will be utilized to ascertain the role dust may play in future machines such as ITER where significant dust production from wall erosion is expected. NSTX has numerous view ports including both tangential as well as radial views in both the midplane and lower divertors. Several vertical ports are also available so that a few specific regions in NSTX may be viewed simultaneously from several different camera positions. The cameras can be operated in the full visible spectrum but near-infrared filters can be utilized to enhance the observation of incandescent particles against a bright background. A description of the cameras and required optics is presented.

Roquemore, A. L.; Davis, W.; Kaita, R.; Skinner, C. H.; Maqueda, R.; Nishino, N. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Nova Photonics, Inc., Princeton, New Jersey 08540 (United States); Hiroshima University, Hiroshima 739-8527 (Japan)

2006-10-15T23:59:59.000Z

11

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

E-Print Network [OSTI]

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

Kushner, Mark

12

Color-based tracking of plasma dust particles  

SciTech Connect (OSTI)

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.

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

13

Optical Investigations of Dust Particles Distribution in RF and DC Discharges  

SciTech Connect (OSTI)

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

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

2008-09-07T23:59:59.000Z

14

Ice Nuclei in Marine Air: Biogenic Particles or Dust?  

SciTech Connect (OSTI)

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

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

2013-01-11T23:59:59.000Z

15

Three-dimensional Reconstruction of Dust Particle Trajectories in the NSTX  

SciTech Connect (OSTI)

Highly mobile incandescent dust particles are routinely observed on NSTX using two fast cameras operating in the visible region. An analysis method to reconstruct dust particle trajectories in space using two fast cameras is presented in this paper. Position accuracies of a few millimeters depending on the particle's location have been achieved and particle velocities between 10 and 200 m/s have been observed. 2008 American Institute of Physics. __________________________________________________

W.U. Boeglin, A.L. Roquemore, and R. Maqueda

2009-03-06T23:59:59.000Z

16

Three-dimensional reconstruction of dust particle trajectories in the NSTX  

SciTech Connect (OSTI)

Highly mobile incandescent dust particles are routinely observed on NSTX using two fast cameras operating in the visible region. An analysis method to reconstruct dust particle trajectories in space using two fast cameras is presented in this paper. Position accuracies of a few millimeters depending on the particle's location have been achieved and particle velocities between 10 and 200 m/s have been observed.

Boeglin, W. U. [Physics Department, Florida International University, 11200 SW 8th Street, Miami, Florida 33199 (United States); Roquemore, A. L. [Princeton Plasma Physics Laboratory, James Forrestal Campus, Rt. 1 N at Sayre Dr., Princeton, New Jersey 08543 (United States); Maqueda, R. [NOVA Photonics, P.O. Box 451, Princeton, New Jersey 08543-0451 (United States)

2008-10-15T23:59:59.000Z

17

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]

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...

Feng, Qian

2011-10-21T23:59:59.000Z

18

APS/123-QED Influence of the ambipolar-to-free diffusion transition on dust particle charge in a  

E-Print Network [OSTI]

and the thermophoretic force [10, 11]. Dust particle charge is a key parameter in a complex plasma. It determines

Paris-Sud XI, Université de

19

TURBULENCE-INDUCED RELATIVE VELOCITY OF DUST PARTICLES. I. IDENTICAL PARTICLES  

SciTech Connect (OSTI)

We study the relative velocity of inertial particles suspended in turbulent flows and discuss implications for dust particle collisions in protoplanetary disks. We simulate a weakly compressible turbulent flow, evolving 14 particle species with friction timescale, ?{sub p}, covering the entire range of scales in the flow. The particle Stokes numbers, St, measuring the ratio of ?{sub p} to the Kolmogorov timescale, are in the range 0.1 ?< St ?< 800. Using simulation results, we show that the model by Pan and Padoan gives satisfactory predictions for the rms relative velocity between identical particles. The probability distribution function (PDF) of the relative velocity is found to be highly non-Gaussian. The PDF tails are well described by a 4/3 stretched exponential function for particles with ?{sub p} ? 1-2 T{sub L}, where T{sub L} is the Lagrangian correlation timescale, consistent with a prediction based on PP10. The PDF approaches Gaussian only for very large particles with ?{sub p} ?> 54 T{sub L}. We split particle pairs at given distances into two types with low and high relative speeds, referred to as continuous and caustic types, respectively, and compute their contributions to the collision kernel. Although amplified by the effect of clustering, the continuous contribution vanishes in the limit of infinitesimal particle distance, where the caustic contribution dominates. The caustic kernel per unit cross section rises rapidly as St increases toward ? 1, reaches a maximum at ?{sub p} ? 2 T{sub L}, and decreases as ?{sub p}{sup -1/2} for ?{sub p} >> T{sub L}.

Pan, Liubin [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Padoan, Paolo, E-mail: lpan@cfa.harvard.edu, E-mail: ppadoan@icc.ub.edu [ICREA and ICC, University of Barcelona, Marti i Franquès 1, E-08028 Barcelona (Spain)

2013-10-10T23:59:59.000Z

20

Identification of isotopically primitive interplanetary dust particles: A NanoSIMS isotopic imaging study  

E-Print Network [OSTI]

Identification of isotopically primitive interplanetary dust particles: A NanoSIMS isotopic imaging contain larger regions with more modest enrichments in 15 N, leading to average bulk N isotopic of those IDPs that have anomalous bulk N isotopic compositions. These particles typically also contain

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


21

FROM DUST TO PLANETESIMALS: CRITERIA FOR GRAVITATIONAL INSTABILITY OF SMALL PARTICLES IN GAS  

SciTech Connect (OSTI)

Dust particles sediment toward the midplanes of protoplanetary disks, forming dust-rich sublayers encased in gas. What densities must the particle sublayer attain before it can fragment by self-gravity? We describe various candidate threshold densities. One of these is the Roche density, which is that required for a strengthless satellite to resist tidal disruption by its primary. Another is the Toomre density, which is that required for de-stabilizing self-gravity to defeat the stabilizing influences of pressure and rotation. We show that for sublayers containing aerodynamically well-coupled dust, the Toomre density exceeds the Roche density by many (up to about four) orders of magnitude. We present three-dimensional shearing box simulations of self-gravitating, stratified, dust-gas mixtures to test which of the candidate thresholds is relevant for collapse. All of our simulations indicate that the larger Toomre density is required for collapse. This result is sensible because sublayers are readily stabilized by pressure. Sound-crossing times for thin layers are easily shorter than free-fall times, and the effective sound speed in dust-gas suspensions decreases only weakly with the dust-to-gas ratio (as the inverse square root). Our findings assume that particles are small enough that their stopping times in gas are shorter than all other timescales. Relaxing this assumption may lower the threshold for gravitational collapse back down to the Roche criterion. In particular, if the particle stopping time becomes longer than the sound-crossing time, then sublayers may lose pressure support and become gravitationally unstable.

Shi, Ji-Ming; Chiang, Eugene, E-mail: jmshi@berkeley.edu [Department of Astronomy, UC Berkeley, Hearst Field Annex B-20, Berkeley, CA 94720-3411 (United States)] [Department of Astronomy, UC Berkeley, Hearst Field Annex B-20, Berkeley, CA 94720-3411 (United States)

2013-02-10T23:59:59.000Z

22

Surface States and the Charge of a Dust Particle in a Plasma  

SciTech Connect (OSTI)

We investigate electron and ion surface states of a negatively charged dust particle in a gas discharge and identify the charge of the particle with the electron surface density bound in the polarization-induced short-range part of the particle potential. On that scale, ions do not affect the charge. They are trapped in the shallow states of the Coulomb tail of the potential and act only as screening charges. Using orbital-motion limited electron charging fluxes and the particle temperature as an adjustable parameter, we obtain excellent agreement with experimental data.

Bronold, F. X.; Fehske, H.; Deutsch, H. [Institut fuer Physik, Ernst-Moritz-Arndt-Universitaet Greifswald, D-17489 Greifswald (Germany); Kersten, H. [Institut fuer Experimentelle und Angewandte Physik, Christian-Albrechts-Universitaet zu Kiel, D-24098 Kiel (Germany)

2008-10-24T23:59:59.000Z

23

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

SciTech Connect (OSTI)

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

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

2012-10-01T23:59:59.000Z

24

Collection strategy, inner morphology, and size distribution of dust particles in ASDEX Upgrade  

SciTech Connect (OSTI)

The dust collection and analysis strategy in ASDEX Upgrade (AUG) is described. During five consecutive operation campaigns (2007–2011), Si collectors were installed, which were supported by filtered vacuum sampling and collection with adhesive tapes in 2009. The outer and inner morphology (e.g. shape) and elemental composition of the collected particles were analysed by scanning electron microscopy. The majority of the ~50?000 analysed particles on the Si collectors of campaign 2009 contain tungsten—the plasma-facing material in AUG—and show basically two different types of outer appearance: spheroids and irregularly shaped particles. By far most of the W-dominated spheroids consist of a solid W core, i.e. solidified W droplets. A part of these particles is coated with a low-Z material; a process that seems to happen presumably in the far scrape-off layer plasma. In addition, some conglomerates of B, C and W appear as spherical particles after their contact with plasma. By far most of the particles classified as B-, C- and W-dominated irregularly shaped particles consist of the same conglomerate with varying fraction of embedded W in the B–C matrix and some porosity, which can exceed 50%. The fragile structures of many conglomerates confirm the absence of intensive plasma contact. Both the ablation and mobilization of conglomerate material and the production of W droplets are proposed to be triggered by arcing. The size distribution of each dust particle class is best described by a log-normal distribution allowing an extrapolation of the dust volume and surface area. The maximum in this distribution is observed above the resolution limit of 0.28 µm only for the W-dominated spheroids, at around 1 µm. The amount of W-containing dust is extrapolated to be less than 300 mg on the horizontal areas of AUG.

M. Balden; N. Endstrasser; P. W. Humrickhouse; V. Rohde; M. Rasinski; U. von Toussaint; S. Elgeti; R. Neu

2014-04-01T23:59:59.000Z

25

Statistical charge distribution over dust particles in a non-Maxwellian Lorentzian plasma  

SciTech Connect (OSTI)

On the basis of statistical mechanics and charging kinetics, the charge distribution over uniform size spherical dust particles in a non-Maxwellian Lorentzian plasma is investigated. Two specific situations, viz., (i) the plasma in thermal equilibrium and (ii) non-equilibrium state where the plasma is dark (no emission) or irradiated by laser light (including photoemission) are taken into account. The formulation includes the population balance equation for the charged particles along with number and energy balance of the complex plasma constituents. The departure of the results for the Lorentzian plasma, from that in case of Maxwellian plasma, is graphically illustrated and discussed; it is shown that the charge distribution tends to results corresponding to Maxwellian plasma for large spectral index. The charge distribution predicts the opposite charging of the dust particles in certain cases.

Mishra, S. K. [Institute for Plasma Research (IPR), Gandhinagar-382428 (India); Misra, Shikha, E-mail: shikhamish@gmail.com [Centre for Energy Studies (CES), Indian Institute of Technology Delhi (IITD), New Delhi-110016 (India)

2014-07-15T23:59:59.000Z

26

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

E-Print Network [OSTI]

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

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

2013-06-11T23:59:59.000Z

27

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

SciTech Connect (OSTI)

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

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

2013-03-15T23:59:59.000Z

28

Heterogeneous Chemistry of Individual Mineral Dust Particles with Nitric Acid. A Combined CCSEM/EDX, ESEM AND ICP-MS Study  

SciTech Connect (OSTI)

The heterogeneous chemistry of individual dust particles from four authentic dust samples with gas-phase nitric acid was investigated in this study. Morphology and compositional changes of individual particles as they react with nitric acid 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 investigate the hygroscopic behavior of mineral dust particles reacted with nitric acid. Differences in the reactivity of mineral dust particles from these four different dust source regions with nitric acid were observed. Mineral dust from source regions containing high levels of calcium, namely China loess dust and Saudi coastal dust, were found to react to the greatest extent.

Laskin, Alexander; Wietsma, Thomas W.; Krueger, Brenda J.; Grassian, Vicki H.

2005-05-26T23:59:59.000Z

29

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

E-Print Network [OSTI]

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

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

2013-01-01T23:59:59.000Z

30

Transport mechanisms and experimental evidence of positively charged dust particles in an argon plasma  

SciTech Connect (OSTI)

It is well known that dense particle clouds often reside within the steady-state plasma; however, particle transport in the critical post-plasma period has not yet been fully explored. To better understand and characterize particle behavior, charge and transport properties of dust particles in an argon plasma, contained within a Gaseous Electronics Conference (GEC) reference cell, were studied in the steady-state and post-plasma regimes of a 500 mTorr, 25 W argon discharge. Using separate water chillers to control independently the temperatures of the upper and lower electrodes, various temperature gradients were imposed on the plasma and thermophoretic transport of the particle clouds observed for both steady and decaying discharges. Next, using a pulsed rf power supply and a tuned Langmuir probe, the decay times of electrons and ions were measured in the afterglow. Finally, utilizing high-speed video in concert with 10 mW He-Ne laser light, post-plasma particle trajectories were observed for various electric fields and electrode temperatures. Results were then compared to calculations from a net force model that included gravity, the electric field, fluid flow, ion drag, and thermophoresis. It was found that temperature gradients greater than {approximately} 10 C/cm significantly altered particle cloud configurations in steady plasmas, and provided a strong transport mechanism in the afterglow. Electrically, the measured ion density decay time was approximately equal to that of the electrons, consistent with ambipolar diffusion.

Brown, D.A.; Hareland, W.A. [Sandia National Labs., Albuquerque, NM (United States); Collins, S.M. [Univ. of Arizona, Tucson, AZ (United States)

1995-12-31T23:59:59.000Z

31

Improving Simulations of Fine Dust Surface Concentrations over the Western United States by Optimizing the Particle Size Distribution  

SciTech Connect (OSTI)

To improve estimates of remote contributions of dust to fine particulate matter (PM2.5) in the western United States, new dust particle size distributions (PSDs) based upon scale-invariant fragmentation theory (Kok_PSD) with constraints from in situ measurements (IMP_PSD) are implemented in a chemical transport model (GEOS-Chem). Compared to initial simulations, this leads to reductions in the mass of emitted dust particles with radii <1.8 mm by 40%-60%. Consequently, the root-mean-square error in simulated fine dust concentrations compared to springtime surface observations in the western United States is reduced by 67%-81%. The ratio of simulated fine to coarse PM mass is also improved, which is not achievable by reductions in total dust emissions. The IMP_PSD best represents the PSD of dust transported from remote sources and reduces modeled PM2.5 concentrations up to 5 mg/m3 over the western United States, which is important when considering sources contributing to nonattainment of air quality standards. Citation: Zhang, L., J. F. Kok, D. K. Henze, Q. Li, and C. Zhao (2013), Improving simulations of fine dust surface concentrations over the western United States by optimizing the particle size distribution, Geophys. Res. Lett., 40, 3270-3275, doi:10.1002/grl.50591.

Zhang, Li; Kok, Jasper F.; Henze, Daven; Li, Qinbin; Zhao, Chun

2013-06-28T23:59:59.000Z

32

The response of a capacitively coupled discharge to the formation of dust particles: Experiments and modeling  

SciTech Connect (OSTI)

The influence of dust particles on the properties of a capacitively coupled Ar-C{sub 2}H{sub 2} discharge is studied both experimentally and theoretically. The results of measurements of the intensity and spatial distribution of the emitted light, the line width of the fast component of H{sub {alpha}} line and of the electron density during the particle growth are presented. To analyze the experimental results a one-dimensional discharge model is developed. Using the model the effects of dust grains on the power absorption (taking into account stochastic and Ohmic heating in the plasma sheaths), the optical emission intensity profile, the sheath size, the rf electric field and on the energy of positive ions bombarding the electrodes are investigated. In particular, it is shown that the decrease of the power absorption in the sheaths of complex plasmas is due to the dependence of the stochastic and Ohmic heating in the plasma sheaths on the electron temperature and the current flowing across the discharge plates. The results of the calculations are compared with the available experimental data and found to be in good agreement.

Denysenko, I.; Berndt, J.; Kovacevic, E.; Stefanovic, I.; Selenin, V.; Winter, J. [School of Physics and Technology, V. N. Karazin Kharkiv National University, Svobody sq. 4, 61077 Kharkiv (Ukraine); Institute of Experimental Physics II, Ruhr-University Bochum, D-44780 Bochum (Germany); Institute of Experimental Physics II, Ruhr-University Bochum, D-44780 Bochum, Germany and Institute of Physics, POB 57, 11001 Belgrade (Serbia and Montenegro); Institute of Experimental Physics II, Ruhr-University Bochum, D-44780 Bochum (Germany)

2006-07-15T23:59:59.000Z

33

Observation of plasma instabilities related to dust particle growth mechanisms in electron cyclotron resonance plasmas  

SciTech Connect (OSTI)

Instabilities are observed in the self-bias voltage measured on a probe immersed in microwave plasma excited at Electron Cyclotron Resonance (ECR). Observed in the MHz range, they were systematically measured in dust-free or dusty plasmas (obtained for different conditions of applied microwave powers and acetylene flow rates). Two characteristic frequencies, well described as lower hybrid oscillations, can be defined. The first one, in the 60–70 MHz range, appears as a sharp peak in the frequency spectra and is observed in every case. Attributed to ions, its position shift observed with the output power highlights that nucleation process takes place in the dusty plasma. Attributed to lower hybrid oscillation of powders, the second broad peak in the 10–20 MHz range leads to the characterization of dust particles growth mechanisms: in the same way as in capacitively coupled plasmas, accumulation of nucleus confined near the probe in the magnetic field followed by aggregation takes place. Then, the measure of electrical instabilities on the self-bias voltage allows characterizing the discharge as well as the chemical processes that take place in the magnetic field region and their kinetics.

Drenik, A. [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia) [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); CNRS, LAPLACE, 31062 Toulouse/Université de Toulouse, UPS, INPT, LAPLACE, 118 rte de Narbonne, 31062 Toulouse Cedex 9 (France); Yuryev, P.; Clergereaux, R. [CNRS, LAPLACE, 31062 Toulouse/Université de Toulouse, UPS, INPT, LAPLACE, 118 rte de Narbonne, 31062 Toulouse Cedex 9 (France)] [CNRS, LAPLACE, 31062 Toulouse/Université de Toulouse, UPS, INPT, LAPLACE, 118 rte de Narbonne, 31062 Toulouse Cedex 9 (France); Vesel, A. [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia)] [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Margot, J. [Groupe de Physique des Plasmas, Département de Physique, Université de Montréal, CP 6128, Succursale Centre-ville, Montréal, Québec H3C 3J7 (Canada)] [Groupe de Physique des Plasmas, Département de Physique, Université de Montréal, CP 6128, Succursale Centre-ville, Montréal, Québec H3C 3J7 (Canada)

2013-10-15T23:59:59.000Z

34

Influence by small dispersive coal dust particles of different fractional consistence on characteristics of iodine air filter at nuclear power plant  

E-Print Network [OSTI]

The main purpose of research is to determine the influence by the small dispersive coal dust particles of the different fractional consistence on the technical characteristics of the vertical iodine air filter at nuclear power plant. The research on the transport properties of the small dispersive coal dust particles in the granular filtering medium of absorber in the vertical iodine air filter is completed in the case, when the modeled aerodynamic conditions are similar to the real aerodynamic conditions. It is shown that the appearance of the different fractional consistence of small dispersive coal dust particles with the decreasing dimensions down to the micro and nano sizes at the action of the air dust aerosol stream normally results in a significant change of distribution of the small dispersive coal dust particles masses in the granular filtering medium of an absorber in the vertical iodine air filter, changing the vertical iodine air filter aerodynamic characteristics. The precise characterization of...

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

2013-01-01T23:59:59.000Z

35

Dust Measurements in Tokamaks  

SciTech Connect (OSTI)

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.

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

36

Modified theory of secondary electron emission from spherical particles and its effect on dust charging in complex plasma  

SciTech Connect (OSTI)

The authors have modified Chow's theory of secondary electron emission (SEE) to take account of the fact that the path length of a primary electron in a spherical particle varies between zero to the diameter or x{sub m} the penetration depth depending on the distance of the path from the centre of the particle. Further by including this modified expression for SEE efficiency, the charging kinetics of spherical grains in a Maxwellian plasma has been developed; it is based on charge balance over dust particles and number balance of electrons and ionic species. It is seen that this effect is more pronounced for smaller particles and higher plasma temperatures. Desirable experimental work has also been discussed.

Misra, Shikha [Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi-110016 (India); Mishra, S. K. [Institute for Plasma Research, Gandhinagar-382428 (India); Sodha, M. S. [Department of Education Building, University of Lucknow, Lucknow-226007 (India)

2013-01-15T23:59:59.000Z

37

Erratum To "Heterogeneous Chemistry of Individual Mineral Dust Particles From Different Dust Source Regions: The Importance of Particle Mineralogy" [Atmos.Environ.38 (36)(2004)6253 –6261  

SciTech Connect (OSTI)

The publisher regrets that there was an error in the information in Table 1 incorrectly identifies the mineral dust and their corresponding composition. The corrected table is given below. In addition, the second full sentence below the table should read “Smaller amounts ?1% of other elements such as V and Ti were also observed but are not listed in Table 1 and is the reason why the percentages do not total to 100 in Table 1.” In the original article it states that K was not included in Table 1 but clearly it is.

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

2005-01-01T23:59:59.000Z

38

Characterization of secondary grain dust explosions  

E-Print Network [OSTI]

dust less than 106 um . . . ~ . . ~ ~ ~ ~ 27 4 Coulter Counter particle size distribution for wheat dust less than 106 um . 28 5 Coulter Counter particle size distribution for rice dust less than 106 um ~ 29 6 Coulter Counter particle size... distribution f' or wheat/sorghum dust, less than 106 um . 7 Coulter Counter particle size distribution for soybean dust less than 106 um 31 8 Coulter Counter particle size distribution for corn dust between 106 and. 250 um 9 Coulter Counter particle size...

Schulman, Cheryl Wendler

2012-06-07T23:59:59.000Z

39

Distribution of small dispersive coal dust particles and absorbed radioactive chemical elements in conditions of forced acoustic resonance in iodine air filter at nuclear power plant  

E-Print Network [OSTI]

The physical features of distribution of the small dispersive coal dust particles and the adsorbed radioactive chemical elements and their isotopes in the absorber with the granular filtering medium with the cylindrical coal granules were researched in the case of the intensive air dust aerosol stream flow through the iodine air filter (IAF). It was shown that, at the certain aerodynamic conditions in the IAF, the generation of the acoustic oscillations is possible. It was found that the acoustic oscillations generation results in an appearance of the standing acoustic waves of the air pressure (density) in the IAF. In the case of the intensive blow of the air dust aerosol, it was demonstrated that the standing acoustic waves have some strong influences on both: 1) the dynamics of small dispersive coal dust particles movement and their accumulation in the IAF; 2) the oversaturation of the cylindrical coal granules by the adsorbed radioactive chemical elements and their isotopes in the regions, where the antin...

Ledenyov, Oleg P

2013-01-01T23:59:59.000Z

40

Influence by small dispersive coal dust particles of different fractional consistence on characteristics of iodine air filter at nuclear power plant  

E-Print Network [OSTI]

The main purpose of research is to determine the influence by the small dispersive coal dust particles of the different fractional consistence on the technical characteristics of the vertical iodine air filter at nuclear power plant. The research on the transport properties of the small dispersive coal dust particles in the granular filtering medium of absorber in the vertical iodine air filter is completed in the case, when the modeled aerodynamic conditions are similar to the real aerodynamic conditions. It is shown that the appearance of the different fractional consistence of small dispersive coal dust particles with the decreasing dimensions down to the micro and nano sizes at the action of the air dust aerosol stream normally results in a significant change of distribution of the small dispersive coal dust particles masses in the granular filtering medium of an absorber in the vertical iodine air filter, changing the vertical iodine air filter aerodynamic characteristics. The precise characterization of the aerodynamic resistance of a model of the vertical iodine air filter is completed. The comparative analysis of the technical characteristics of the vertical and horizontal iodine air filters is also made.

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

2013-02-18T23:59:59.000Z

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


41

Comparison of the Coulter Multisizer and Aerodynamic Particle Sizer for obtaining the aerodynamic particle size of irregularly shaped dust  

E-Print Network [OSTI]

When studying air quality it is often necessary to measure the aerodynamic size distribution of particles. True aerodynamic diameter must be measured using a gravitational settling method, which is impractical. Other methods exist that use other...

McClure, Joshua Wayne

2002-01-01T23:59:59.000Z

42

Recovering the Elemental Composition of Comet Wild 2 Dust in Five Stardust Impact Tracks and Terminal Particles in Aerogel  

SciTech Connect (OSTI)

The elemental (non-volatile) composition of five Stardust impact tracks and terminal particles left from capture of Comet 81P/Wild 2 dust were mapped in a synchrotron x-ray scanning microprobe with full fluorescence spectra at each pixel. Because aerogel includes background levels of several elements of interest, we employ a novel 'dual threshold' approach to discriminate against background contaminants: an upper threshold, above which a spectrum contains cometary material plus aerogel and a lower threshold below which it contains only aerogel. The difference between normalized cometary-plus-background and background-only spectra is attributable to cometary material. The few spectra in between are discarded since misallocation is detrimental: cometary material incorrectly placed in the background spectrum is later subtracted from the cometary spectrum, doubling the loss of reportable cometary material. This approach improves precision of composition quantification. We present the refined whole impact track and terminal particle elemental abundances for the five impact tracks. One track shows mass increases in Cr and Mn (1.4x), Cu, As and K (2x), Zn (4x) and total mass (13%) by dual thresholds compared to a single threshold. Major elements Fe and Ni are not significantly affected. The additional Cr arises from cometary material containing little Fe. We exclude Au intermixed with cometary material because it is found to be a localized surface contaminant carried by comet dust into an impact track. The dual threshold technique can be used in other situations where elements of interest in a small sample embedded in a matrix are also present in the matrix itself.

Ishii, H A; Brennan, S; Bradley, J P; Luening, K; Ignatyev, K; Pianetta, P

2007-01-04T23:59:59.000Z

43

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

E-Print Network [OSTI]

Aerosol size distribution The size of an aerosol particle is an important parameter that controls the rates of diffusion, coagulation,coagulation into the larger ultrafine and accumulation Figure 1.1. Typical size distribution of atmospheric aerosols and

Sullivan, Ryan Christopher

2008-01-01T23:59:59.000Z

44

Modular Sampling and Analysis Techniques for the Real-Time Analysis of Human Breath  

SciTech Connect (OSTI)

At LLNL and UC Davis, we are developing several techniques for the real-time sampling and analysis of trace gases, aerosols and exhaled breath that could be useful for a modular, integrated system for breath analysis. Those techniques include single-particle bioaerosol mass spectrometry (BAMS) for the analysis of exhaled aerosol particles or droplets as well as breath samplers integrated with gas chromatography mass spectrometry (GC-MS) or MEMS-based differential mobility spectrometry (DMS). We describe these techniques and present recent data obtained from human breath or breath condensate, in particular, addressing the question of how environmental exposure influences the composition of breath.

Frank, M; Farquar, G; Adams, K; Bogan, M; Martin, A; Benner, H; Spadaccini, C; Steele, P; Davis, C; Loyola, B; Morgan, J; Sankaran, S

2007-07-09T23:59:59.000Z

45

Secondary dust density waves excited by nonlinear dust acoustic waves  

SciTech Connect (OSTI)

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.

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

46

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

Nittler, Larry R.

47

Images of Vega Dust Ring at 350 and 450 microns: New Clues to the Trapping of Multiple-Sized Dust Particles in Planetary Resonances  

E-Print Network [OSTI]

We have used the SHARC II camera at Caltech Submillimeter Observatory to make 350 and 450 micron images of the Vega dust disk at spatial resolutions (FWHM) of 9.7" and 11.1", respectively. The images show a ring-like morphology (radius \\~ 100 AU) with inhomogeneous structure that is qualitatively different from that previously reported at 850 microns and longer wavelengths. We attribute the 350/450 micron emission to a grain population whose characteristic size (~ 1 mm) is intermediate between that of the cm-sized grains responsible for emission longward of 850 microns and the much smaller grains (< 18 microns) in the extensive halo, visible at 70 microns, discussed by Su et al. (2005). We have combined our submillimeter images with Spitzer data at 70 microns to produce 2-d maps of line-of-sight optical depth (relative column density). These "tau maps" suggest that the mm-sized grains are located preferentially in three symmetrically-located concentrations. If so, then this structure could be understood in terms of the Wyatt (2003) model in which planetesimals are trapped in the mean motion resonances of a Neptune-mass planet at 65 AU, provided allowance is made for the spatial distribution of dust grains to differ from that of the parent planetesimals. The peaks of the tau maps are, in fact, located near the expected positions corresponding to the 4:3 resonance. If this identification is confirmed by future observations, it would resolve an ambiguity with regard to the location of the planet.

K. A. Marsh; C. D. Dowell; T. Velusamy; K. Grogan; C. A. Beichman

2006-06-14T23:59:59.000Z

48

Distribution of small dispersive coal dust particles and absorbed radioactive chemical elements in conditions of forced acoustic resonance in iodine air filter at nuclear power plant  

E-Print Network [OSTI]

The physical features of distribution of the small dispersive coal dust particles and the adsorbed radioactive chemical elements and their isotopes in the absorber with the granular filtering medium with the cylindrical coal granules were researched in the case of the intensive air dust aerosol stream flow through the iodine air filter (IAF). It was shown that, at the certain aerodynamic conditions in the IAF, the generation of the acoustic oscillations is possible. It was found that the acoustic oscillations generation results in an appearance of the standing acoustic waves of the air pressure (density) in the IAF. In the case of the intensive blow of the air dust aerosol, it was demonstrated that the standing acoustic waves have some strong influences on both: 1) the dynamics of small dispersive coal dust particles movement and their accumulation in the IAF; 2) the oversaturation of the cylindrical coal granules by the adsorbed radioactive chemical elements and their isotopes in the regions, where the antinodes of the acoustic waves are positioned. Finally, we completed the comparative analysis of the theoretical calculations with the experimental results, obtained for the cases of: 1) the experimental aerodynamic modeling of physical processes of the absorbed radioactive chemical elements and their isotopes distribution in the IAF; and 2) the gamma-activation spectroscopy analysis of the absorbed radioactive chemical elements and their isotopes distribution in the IAF. We made the innovative propositions on the necessary technical modifications with the purpose to improve the IAF technical characteristics and increase its operational time at the nuclear power plant (NPP), going from the completed precise characterization of the IAF parameters at the long term operation.

Oleg P. Ledenyov; Ivan M. Neklyudov

2013-06-14T23:59:59.000Z

49

Infrared Spectroscopy of Wild 2 Particle Hypervelocity Tracks in Stardust Aerogel: Evidence for the presence of Volatile Organics in Comet Dust  

SciTech Connect (OSTI)

Infrared spectroscopy maps of some tracks, made by cometary dust from 81P/Wild 2 impacting Stardust aerogel, reveal an interesting distribution of volatile organic material. Out of six examined tracks three show presence of volatile organic components possibly injected into the aerogel during particle impacts. When particle tracks contained excess volatile organic material, they were found to be -CH{sub 2}-rich. Off-normal particle tracks could indicate impacts by lower velocity particles that could have bounced off the Whipple shield, therefore carry off some contamination from it. However, this theory is not supported by data that show excess organic-rich material in normal and off-normal particle tracks. It is clear that the population of cometary particles impacting the Stardust aerogel collectors also include grains that contained little or none of this volatile organic component. This observation is consistent with the highly heterogeneous nature of the collected grains, as seen by a multitude of other analytical techniques. We propose that at least some of the volatile organic material might be of cometary origin based on supporting data shown in this paper. However, we also acknowledge the presence of carbon (primarily as -CH{sub 3}) in the original aerogel, which complicates interpretation of these results.

Bajt, S; Sandford, S A; Flynn, G J; Matrajt, G; Snead, C J; Westphal, A J; Bradley, J P

2007-08-28T23:59:59.000Z

50

Dust cluster explosion  

SciTech Connect (OSTI)

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

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

2012-09-15T23:59:59.000Z

51

Iron Speciation in Urban Dust  

SciTech Connect (OSTI)

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.

E Elzinga; Y Gao; J Fitts; R Tappero

2011-12-31T23:59:59.000Z

52

Comparison of the oxidation state of Fe in comet 81P/Wild 2 and chondritic-porous interplanetary dust particles  

SciTech Connect (OSTI)

The fragile structure of chondritic-porous interplanetary dust particles (CP-IDPs) and their minimal parent-body alteration have led researchers to believe these particles originate in comets rather than asteroids where aqueous and thermal alterations have occurred. The solar elemental abundances and atmospheric entry speed of CP-IDPs also suggest a cometary origin. With the return of the Stardust samples from Jupiter-family comet 81P/Wild 2, this hypothesis can be tested. We have measured the Fe oxidation state of 15 CP-IDPs and 194 Stardust fragments using a synchrotron-based x-ray microprobe. We analyzed {approx}300 ng of Wild 2 material - three orders of magnitude more material than other analyses comparing Wild 2 and CP-IDPs. The Fe oxidation state of these two samples of material are > 2{sigma} different: the CP-IDPs are more oxidized than the Wild 2 grains. We conclude that comet Wild 2 contains material that formed at a lower oxygen fugacity than the parent-body, or parent bodies, of CP-IDPs. If all Jupiter-family comets are similar, they do not appear to be consistent with the origin of CP-IDPs. However, comets that formed from a different mix of nebular material and are more oxidized than Wild 2 could be the source of CP-IDPs.

Ogliore, Ryan C.; Butterworth, Anna L.; Fakra, Sirine C.; Gainsforth, Zack; Marcus, Matthew A.; Westphal, Andrew J.

2010-07-16T23:59:59.000Z

53

Breathing zone air sampler  

SciTech Connect (OSTI)

A sampling apparatus is provided which comprises a sampler for sampling air in the breathing zone of a wearer of the apparatus and a support for the sampler preferably in the form of a pair of eyeglasses. The sampler comprises a sampling assembly supported on the frame of the eyeglasses and including a pair of sample transport tubes which are suspended, in use, centrally of the frame so as to be disposed on opposite sides of the nose of the wearer and which each include an inlet therein that, in use, is disposed adjacent to a respective nostril of the nose of the wearer. A filter holder connected to sample transport tubes supports a removable filter for filtering out particulate material in the air sampled by the apparatus. The sample apparatus is connected to a pump for drawing air into the apparatus through the tube inlets so that the air passes through the filter.

Tobin, John (Bethel Park, PA)

1989-01-01T23:59:59.000Z

54

Breathing zone air sampler  

SciTech Connect (OSTI)

A sampling apparatus is presented which comprises a sampler for sampling air in the breathing zone of a wearer of the apparatus and a support for the sampler preferably in the form of a pair of eyeglasses. The sampler comprises a sampling assembly supported on the frame of the eyeglasses and including a pair of sample transport tubes which are suspended, in use, centrally of the frame so as to be disposed on opposite sides of the nose of the wearer and which each include an inlet therein that, in use, is disposed adjacent to a respective nostril of the nose of the wearer. A filter holder connected to sample transport tubes supports a removable filter for filtering out particulate material in the air sampled by the apparatus. The sample apparatus is connected to a pump for drawing air into the apparatus through the tube inlets so that the air passes through the filter.

Tobin, J.

1989-08-22T23:59:59.000Z

55

A Comprehensive Parameterization of Heterogeneous Ice Nucleation of Dust Surrogate: Laboratory Study with Hematite Particles and Its Application to Atmospheric Models  

SciTech Connect (OSTI)

A new heterogeneous ice nucleation parameterization that covers a wide temperature range (-36 ?C to -78 ?C) is presented. Developing and testing such an ice nucleation parameterization, which is constrained through identical experimental conditions, is critical in order to accurately simulate the ice nucleation processes in cirrus clouds. The surface-scaled ice nucleation efficiencies of hematite particles, inferred by ns, were derived from AIDA (Aerosol Interaction and Dynamics in the Atmosphere) cloud chamber measurements under water subsaturated conditions that were realized by continuously changing temperature (T) and relative humidity with respect to ice (RHice) in the chamber. Our measurements showed several different pathways to nucleate ice depending on T and RHice conditions. For instance, almost independent freezing was observed at -60 ?C < T < -50 ?C, where RHice explicitly controlled ice nucleation efficiency, while both T and RHice played roles in other two T regimes: -78 ?C < T < -60 ?C and -50 ?C < T < -36 ?C. More specifically, observations at T colder than -60 ?C revealed that higher RHice was necessary to maintain constant ns, whereas T may have played a significant role in ice nucleation at T warmer than -50 ?C. We implemented new ns parameterizations into two cloud models to investigate its sensitivity and compare with the existing ice nucleation schemes towards simulating cirrus cloud properties. Our results show that the new AIDA-based parameterizations lead to an order of magnitude higher ice crystal concentrations and inhibition of homogeneous nucleation in colder temperature regions. Our cloud simulation results suggest that atmospheric dust particles that form ice nuclei at lower temperatures, below -36 ?C, can potentially have stronger influence on cloud properties such as cloud longevity and initiation when compared to previous parameterizations.

Hiranuma, Naruki; Paukert, Marco; Steinke, Isabelle; Zhang, Kai; Kulkarni, Gourihar R.; Hoose, Corinna; Schnaiter, Martin; Saathoff, Harald; Mohler, Ottmar

2014-12-10T23:59:59.000Z

56

Dust-Plasma Sheath in an Oblique Magnetic Field  

SciTech Connect (OSTI)

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.

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

2008-09-07T23:59:59.000Z

57

Iron speciation in urban dust  

SciTech Connect (OSTI)

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.

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

2011-08-01T23:59:59.000Z

58

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

E-Print Network [OSTI]

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...

Yi, Bingqi

2013-07-09T23:59:59.000Z

59

Residual dust charges in discharge afterglow  

SciTech Connect (OSTI)

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.

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

60

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...

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


61

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:...

62

Glass Frit Clumping And Dusting  

SciTech Connect (OSTI)

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

Steimke, J. L.

2013-09-26T23:59:59.000Z

63

Mars Exploration Rover (MER) Panoramic Camera (Pancam) Twilight Image Analysis for Determination of Planetary Boundary Layer and Dust Particle Size Parameters  

E-Print Network [OSTI]

to take surface-based measurements to offer support for dust and boundary layer measurements made from remote sensors (Lemmon et al., 2004a). Mars has different atmospheric characteristics from those on Earth. For example, the solar constant for Mars... is approximately 44% of the value for Earth (varying by approximately 20%), and the temperature ranges on Mars (- 125?C to +25?C) slightly ____________ This thesis follows the style of the Journal of Geophysical Research. 2 overlap those on Earth (- 80?C...

Grounds, Stephanie Beth

2012-02-14T23:59:59.000Z

64

Breathing oscillations in enlarged cylindrical-anode-layer Hall plasma accelerator  

SciTech Connect (OSTI)

Breathing oscillations in the discharge of an enlarged cylindrical-anode-layer Hall plasma accelerator are investigated by three-dimensional particle-in-cell (PIC) simulation. Different from the traditional breathing mode in a circular Hall plasma accelerator, the bulk plasma oscillation here is trigged by the potential barrier generated by the concentrated ion beam and substantial enough to compete with the anode voltage. The electric field near the anode is suppressed by the potential barrier thereby decreasing the electron density by {approx}36%. The discharge is restored to the normal level after the concentrated beam explodes and then it completes one cycle of electro-driven breathing oscillation. The breathing mode identified by the PIC simulation has a frequency range of {approx}156 kHz-{approx}250 kHz and does not vary monotonically with the discharge voltage.

Geng, S. F.; Wang, C. X. [Southwestern Institute of Physics, Chengdu 610041 (China) [Southwestern Institute of Physics, Chengdu 610041 (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Tang, D. L.; Qiu, X. M. [Southwestern Institute of Physics, Chengdu 610041 (China)] [Southwestern Institute of Physics, Chengdu 610041 (China); Fu, R. K. Y. [Plasma Technology Limited, Festival Walk Tower, Tat Chee Avenue, Kowloon, Hong Kong (China)] [Plasma Technology Limited, Festival Walk Tower, Tat Chee Avenue, Kowloon, Hong Kong (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)] [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

2013-05-28T23:59:59.000Z

65

Protective supplied breathing air garment  

DOE Patents [OSTI]

A breathing air garment is disclosed for isolating a wearer from hostile environments containing toxins or irritants includes a suit and a separate head protective enclosure or hood engaging a suit collar in sealing attachment. The hood and suit collar are cylindrically shaped and dimensioned to enable the wearer to withdraw his hands from the suit sleeves to perform manual tasks within the hood interior. Breathing air is supplied from an external air line with an air delivery hose attached to the hood interior. The hose feeds air into an annular halo-like fiber-filled plenum having spaced discharge orifices attached to the hood top wall. A plurality of air exhaust/check valves located at the suit extremities cooperate with the hood air delivery system to provide a cooling flow of circulating air from the hood throughout the suit interior. A suit entry seal provided on the suit rear torso panel permits access into the suit and is sealed with an adhesive sealing flap. 17 figs.

Childers, E.L.; Hortenau, E.F. von.

1984-07-10T23:59:59.000Z

66

Dust Studies in DIII-D and TEXTOR  

SciTech Connect (OSTI)

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

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

2009-02-17T23:59:59.000Z

67

The Transformation of Solid Atmospheric Particles into Liquid Droplets Through Heterogeneous Chemistry: Laboratory Insights into the Processing of Calcium Containing Mineral Dust Aerosol in the Troposphere  

SciTech Connect (OSTI)

[1] Individual calcium carbonate particles reacted with gas- phase nitric acid at 293 K have been followed using Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray (EDX) analysis as a function of time and relative humidity (RH). The rate of calcium carbonate to calcium nitrate conversion is significantly enhanced in the presence of water vapor. The SEM images clearly show that solid CaCO3 particles are converted to spherical droplets as the reaction proceeds. The process occurs through a two-step mechanism involving the conversion of calcium carbonate into calcium nitrate followed by the deliquescence of the calcium nitrate product. The change in phase of the particles and the significant reactivity of nitric acid and CaCO3 at low RH are a direct result of the deliquescence of the product at low RH. This is the first laboratory study to show the phase transformation of solid particles into liquid droplets through heterogeneous chemistry.

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

2003-02-15T23:59:59.000Z

68

Isoscalar Breathing Mode State in Zr-90 and Sn-116  

E-Print Network [OSTI]

PHYSICAL RKVIK% C VOLUIHE 21, NUMBER 4 Isoscalar breathing mode state in Zr and "Sn C. M. Rozsa, D. H. Youngblood, J. D. Bronson, Y.-%. Lui, and U. Garg Cyclotron Institute, Texas AckM University, College Station, Texas 77843 (Received 5..., BRONSON, LUI, AND GARG larger opening and served to catch some particles scattered from the first set. For measurements at 0', the beam was passed into the spectrograph and one set of brass defining slits with an open- ing of 6.4' horizontally by 3.V...

Rozsa, C. M.; Youngblood, David H.; Bronson, J. D.; Lui, YW; Garg, U.

1980-01-01T23:59:59.000Z

69

Airborne dust in Saudi Arabia : source areas, entrainment, simulation and composition.  

E-Print Network [OSTI]

??Spatial and temporal characteristics of dust storm activity in Saudi Arabia has been established using coarse-particle (PM10) dust concentrations recorded by the KACST monitoring network… (more)

Alharbi, Badr Hadhidh A

2009-01-01T23:59:59.000Z

70

Secondary Electron Emission from Dust and Its Effect on Charging  

SciTech Connect (OSTI)

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

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

2011-11-29T23:59:59.000Z

71

Transparent self-cleaning dust shield  

DOE Patents [OSTI]

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.

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

2005-06-28T23:59:59.000Z

72

Niamey Dust Observations  

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

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.

Flynn, Connor

73

Dust Combustion Safety Issues for Fusion Applications  

SciTech Connect (OSTI)

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

L. C. Cadwallader

2003-05-01T23:59:59.000Z

74

He Puff System For Dust Detector Upgrade  

SciTech Connect (OSTI)

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

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

2010-10-01T23:59:59.000Z

75

Residual electric charges on dust grains at plasma extinction L. Coudel1, M. Mikikian1, Y. Tessier1, L. Boufendi1, A. A. Samarian2  

E-Print Network [OSTI]

. An upward thermophoretic force was thus applied to dust particles to balance gravity [4] when the plasma

Paris-Sud XI, Université de

76

Dust density effect on complex plasma decay L. Couedel a,b, A.A. Samarian a  

E-Print Network [OSTI]

and supported by comparison to existing experimental data. Key words: Complex plasma, dust, afterglow, decay (PECVD, etching, fusion reactor,etc). The dust particles are charged due to their interactions, the dust particles can be either grown directly in the plasma chamber (by sputtering [6,7] or using

Paris-Sud XI, Université de

77

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

SciTech Connect (OSTI)

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.

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

78

Breath is a mixture of nitrogen, oxygen, carbon dioxide, water  

E-Print Network [OSTI]

12 SCIENCE Breath is a mixture of nitrogen, oxygen, carbon dioxide, water vapour, inert gases. On the basis of proton affinity, the major constituents of air and breath (nitrogen, oxygen, carbon dioxide

79

Haul road dust control  

SciTech Connect (OSTI)

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.

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

2007-10-15T23:59:59.000Z

80

Microchemical investigations of dust emitted by a lead smelter  

SciTech Connect (OSTI)

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.

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

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


81

VOLUME 78, NUMBER 8 P H Y S I C A L R E V I E W L E T T E R S 24 FEBRUARY 1997 Debye Shielding and Particle Correlations in Strongly Coupled Dusty Plasmas  

E-Print Network [OSTI]

in dusty plasma research, while fully aware that the dust particles are strongly coupled, have continued

Otani, Niels F.

82

Chaotic dust dynamics and implications for the hemispherical color asymmetries of the Uranian satellites  

E-Print Network [OSTI]

system Cook and Franklin, 1970), (ii) interstellar dust particles (ISDPs) (Landgraf, 2000), (iii) solar of fast incoming particles like solar photons and cosmic rays cannot generate a hemispherical leading

Hamilton, Douglas P.

83

Generation of dust projectiles passing over an obstacle in the plasma sheath  

SciTech Connect (OSTI)

Dust projectiles were produced in a radio-frequency plasma by increasing 6-fold the radio-frequency power put into the discharge. The initial static dust particles were observed to gain speed while moving away from the confining region and escaped from the inter-electrode space on a ballistic-like trajectory. Single-grain dynamics simulations indicated that the dust particles were accelerated by changes induced in the sheath electric field profile.

Ticos, Catalin M.; Stoica, Daniel S. [National Institute for Laser, Plasma and Radiation Physics, 077125 Bucharest (Romania); Delzanno, Gian Luca [Los Alamos National Laboratory, T-5 Applied Mathematics and Plasma Physics Group, Los Alamos, New Mexico 87545 (United States)

2012-08-15T23:59:59.000Z

84

Dust suppression results using mineral oil applications on corn and milo  

E-Print Network [OSTI]

distribution (MCPSD) analysis, to determine the amount and particle size of the dust captured on the grain surface. Statistical analyses were performed on the effects due to dust concentration, mineral oil application and mineral oil*dust interaction. Each... TO CORN BENEFITS OF ADDING MINERAL OIL TO MILO 96 . 97 23 TREATMENT DESCRIPTION OP CORN SAMPLES USED FOR TESTING. 104 TREATMENT DESCRIPTION OF MILO SAMPLES USED FOR TESTING, . . . . . . . . . . . . . . PARTICLE SIZE DISTRIBUTION STATISTICS...

Wardlaw, Herman Douglas

1987-01-01T23:59:59.000Z

85

Dust around Type Ia supernovae  

E-Print Network [OSTI]

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

Wang, Lifan

2005-01-01T23:59:59.000Z

86

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

SciTech Connect (OSTI)

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

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

2012-07-15T23:59:59.000Z

87

Control of Dust Inventory in Tokamaks  

SciTech Connect (OSTI)

Particles with sizes ranging from 100 nm to 100 {mu}m are produced in tokamaks by the interaction of the plasma with the first wall materials and divertor. Dust has not yet been of a major concern in existing tokamaks mainly because their quantities are small and these devices are not nuclear facilities. However, in ITER and in future reactors, they could represent operational and potential safety issues. The aim of this paper is thus to describe the dust creation processes in the tokamak environment. The diagnostics and removal techniques that are needed to be implemented to measure and minimise the dust inventory are also presented. The integration of these techniques into a tokamak environment is also discussed.

Rosanvallon, S.; Grisolia, C. [Association Euratom CEA, CEA/DSM/IRFM, Cadarache, 13108 Saint-Paul-lez-Durance (France); Sharpe, P. [Fusion Safety Program, Idaho National Laboratory, 2525 Fremont Avenue, Idaho Falls, ID 83415-3860 (United States); Andrew, P.; Ciattaglia, S.; Pitcher, C. S.; Taylor, N. [ITER Organization, 13108 St Paul lez Durance (France); Furlan, J. [Fusion For Energy, c/Josep Pla, n. 2, Torres Diagonal Litoral, 08019 Barcelona (Spain)

2008-09-07T23:59:59.000Z

88

Houses need to breathe--right?  

SciTech Connect (OSTI)

Houses need to breathe, but we can no longer leave the important functions associated with ventilation to be met accidentally. A designed ventilation system must be considered as much a part of a home as its heating system. Windows are a key part of that system because they allow a quick increase in ventilation for unusual events, but neither they nor a leaky building shell can be counted on to provide minimum levels.

Sherman, Max H.

2004-10-01T23:59:59.000Z

89

Electrostatic dust detector  

DOE Patents [OSTI]

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

Skinner, Charles H. (Lawrenceville, NJ)

2006-05-02T23:59:59.000Z

90

Particle impact damping: influence of material and size  

E-Print Network [OSTI]

In this study, particle impact damping is measured for a cantilever beam with a particle-filled enclosure attached to its free end. Many particle materials are tested: lead spheres, steel spheres, glass spheres, tungsten carbide pellets, lead dust...

Marhadi, Kun Saptohartyadi

2005-02-17T23:59:59.000Z

91

Cotton Gin Dust Explosibility Determinations  

E-Print Network [OSTI]

personnel listed dust found in cotton gins, or gin dust, fueled two explosions in the past. OSHA is required by law to regulate facilities handling explosible dusts to provide a safe working environment for employees. The dust handling facilities must test...

Vanderlick, Francis Jerome

2014-01-06T23:59:59.000Z

92

Apparatus and method for monitoring breath acetone and diabetic diagnostics  

DOE Patents [OSTI]

An apparatus and method for monitoring diabetes through breath acetone detection and quantitation employs a microplasma source in combination with a spectrometer. The microplasma source provides sufficient energy to produce excited acetone fragments from the breath gas that emit light. The emitted light is sent to the spectrometer, which generates an emission spectrum that is used to detect and quantify acetone in the breath gas.

Duan, Yixiang (Los Alamos, NM); Cao, Wenqing (Los Alamos, NM)

2008-08-26T23:59:59.000Z

93

Future Breathing System Requirements for Clean Diesel Engines  

Broader source: Energy.gov (indexed) [DOE]

Breathing System Requirements for Clean Diesel Engines Poster Location P23 Motivation Results Understand engine air system requirements to reduce NOx Identify...

94

Spatiotemporal evolution of dielectric driven cogenerated dust density waves  

SciTech Connect (OSTI)

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.

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

95

Interpretation of Wild 2 Dust Fine Structure: Comparison of Stardust Aluminium Foil Craters to the Three-Dimensional Shape of Experimental Impacts by Artificial Aggregate Particles and Meteorite Powders  

SciTech Connect (OSTI)

New experimental results show that Stardust crater morphology is consistent with interpretation of many larger Wild 2 dust grains being aggregates, albeit most of low porosity and therefore relatively high density. The majority of large Stardust grains (i.e. those carrying most of the cometary dust mass) probably had density of 2.4 g cm{sup -3} (similar to soda-lime glass used in earlier calibration experiments) or greater, and porosity of 25% or less, akin to consolidated carbonaceous chondrite meteorites, and much lower than the 80% suggested for fractal dust aggregates. Although better size calibration is required for interpretation of the very smallest impacting grains, we suggest that aggregates could have dense components dominated by {micro}m-scale and smaller sub-grains. If porosity of the Wild 2 nucleus is high, with similar bulk density to other comets, much of the pore-space may be at a scale of tens of micrometers, between coarser, denser grains. Successful demonstration of aggregate projectile impacts in the laboratory now opens the possibility of experiments to further constrain the conditions for creation of bulbous (Type C) tracks in aerogel, which we have observed in recent shots. We are also using mixed mineral aggregates to document differential survival of pristine composition and crystalline structure in diverse fine-grained components of aggregate cometary dust analogues, impacted onto both foil and aerogel under Stardust encounter conditions.

Kearsley, A T; Burchell, M J; Price, M C; Graham, G A; Wozniakiewicz, P J; Cole, M J; Foster, N J; Teslich, N

2009-12-10T23:59:59.000Z

96

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

DOE Patents [OSTI]

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

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

1988-01-01T23:59:59.000Z

97

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

SciTech Connect (OSTI)

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.

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

98

UNIVERSITY OF CALIFORNIA Breathing, Laughing, Sneezing, Coughing: Model and Control of an Anatomically  

E-Print Network [OSTI]

UNIVERSITY OF CALIFORNIA RIVERSIDE Breathing, Laughing, Sneezing, Coughing: Model and Control be thankful for his guidance. vi #12;ABSTRACT OF THE DISSERTATION Breathing, Laughing, Sneezing, Coughing, March 2009 Dr. Victor Zordan, Chairperson Breathing, laughing, sneezing and coughing are all important

Zordan, Victor

99

E-Print Network 3.0 - alcohol breath tests Sample Search Results  

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

VERSUS SOPHISTICATED MODELS OF BREATH ALCOHOL Summary: Alcohol & Alcoholism, Vol. 31, No. 1, pp. 61-67, 1996 SIMPLE VERSUS SOPHISTICATED MODELS OF BREATH... -2420, USA,...

100

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

SciTech Connect (OSTI)

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.

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

2011-11-15T23:59:59.000Z

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


101

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

SciTech Connect (OSTI)

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

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

2011-03-15T23:59:59.000Z

102

Aspiration tests in aqueous foam using a breathing simulator  

SciTech Connect (OSTI)

Non-toxic aqueous foams are being developed by Sandia National Laboratories (SNL) for the National Institute of Justice (NIJ) for use in crowd control, cell extractions, and group disturbances in the criminal justice prison systems. The potential for aspiration of aqueous foam during its use and the resulting adverse effects associated with complete immersion in aqueous foam is of major concern to the NIJ when examining the effectiveness and safety of using this technology as a Less-Than-Lethal weapon. This preliminary study was designed to evaluate the maximum quantity of foam that might be aspirated by an individual following total immersion in an SNL-developed aqueous foam. A.T.W. Reed Breathing simulator equipped with a 622 Silverman cam was used to simulate the aspiration of an ammonium laureth sulfate aqueous foam developed by SNL and generated at expansion ratios in the range of 500:1 to 1000:1. Although the natural instinct of an individual immersed in foam is to cover their nose and mouth with a hand or cloth, thus breaking the bubbles and decreasing the potential for aspiration, this study was performed to examine a worst case scenario where mouth breathing only was examined, and no attempt was made to block foam entry into the breathing port. Two breathing rates were examined: one that simulated a sedentary individual with a mean breathing rate of 6.27 breaths/minute, and one that simulated an agitated or heavily breathing individual with a mean breathing rate of 23.7 breaths/minute. The results of this study indicate that, if breathing in aqueous foam without movement, an air pocket forms around the nose and mouth within one minute of immersion.

Archuleta, M.M.

1995-12-01T23:59:59.000Z

103

Raman spectroscopy of carbon dust samples from NSTX Y. Raitses a,*, C.H. Skinner a  

E-Print Network [OSTI]

for the diagnosis of the microscopic structure of different forms of carbon. The intensity of D-mode at 1350 cmÃ?1Raman spectroscopy of carbon dust samples from NSTX Y. Raitses a,*, C.H. Skinner a , F. Jiang b , T. The Raman measurements indicate that the production of carbon dust particles in NSTX involves modifications

Duffy, Thomas S.

104

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

SciTech Connect (OSTI)

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

Friesen, F. QL. [Grinnell College, 1115 8th Avenue, Grinnell, IA 50112-1616

2011-01-20T23:59:59.000Z

105

air breathing engine: Topics by E-print Network  

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

fuel cells Z June 2011 Available online 14 June 2011 Keywords: Air-breathing PEM fuel cell Temperature effects Air buoyancy a b s t r a c t The impact of temperature on...

106

air breathing engines: Topics by E-print Network  

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

fuel cells Z June 2011 Available online 14 June 2011 Keywords: Air-breathing PEM fuel cell Temperature effects Air buoyancy a b s t r a c t The impact of temperature on...

107

Cell Breathing in Wireless LANs: Algorithms and Evaluation  

E-Print Network [OSTI]

Cell Breathing in Wireless LANs: Algorithms and Evaluation Paramvir Bahl Mohammad T. Hajiaghayi Kamal Jain Vahab Mirrokni Lili Qiu Amin Saberi Microsoft Research CMU Microsoft Research MIT UT Austin

Hajiaghayi, Mohammad

108

alveolar breath sampling: Topics by E-print Network  

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

16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 41 Breath is a mixture of nitrogen, oxygen, carbon dioxide, water Chemistry Websites Summary: per trillion range....

109

Development of an Electrostatic Dust Detector for use in a Tokamak Reactor  

SciTech Connect (OSTI)

Initial results from a novel device to detect dust particles settling on remote surfaces are presented. Dust particle inventories are a concern in next-step fusion devices. The increase in duty cycle will lead to a scale-up in the amount of particles generated by plasma material interactions. These particles will be chemically and radiologically hazardous and it will be important to establish that the in-vessel particle inventory is within regulatory limits. The detection device consists of two interlocking combs of closely spaced conductive traces on a Teflon circuit board. When a DC bias is applied impinging dust creates a transient short circuit between the traces. The increase in bias current generates a signal pulse that is counted by standard nuclear counting electronics. We present data on the response of the device in air and vacuum to carbon particles.

A. Bader; C.H. Skinner, A.L. Roquemore; S. Langish

2003-09-10T23:59:59.000Z

110

Dust Filtration by Planet-Induced Gap Edges: Implications for Transitional Disks  

E-Print Network [OSTI]

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...

Zhu, Zhaohuan; Dong, Ruobing; Espaillat, Catherine; Hartmann, Lee

2012-01-01T23:59:59.000Z

111

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

SciTech Connect (OSTI)

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.

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

2013-11-05T23:59:59.000Z

112

Raman Spectroscopy of Carbon Dust Samples from NSTX  

SciTech Connect (OSTI)

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.

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

2008-02-21T23:59:59.000Z

113

Cyborg Bugs... and Neural Dust  

E-Print Network [OSTI]

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

California at Irvine, University of

114

Dust suppression characteristics of mineral oil when applied to corn, wheat, or soybeans  

E-Print Network [OSTI]

and must be added repeatedly. Several water applications could raise the mo i stu re content of grain to the point of encouraging mold growth. Peterson (1977) reported that an average worker wi 1 1 breathe from 4 to 10 m of air during an eight hour work... Jones, B. S. , Texas Al!M University Chairman of Advisory Committee: Dr. Calvin B. Parnell, Jr. Corn, wheat, and soybean samples weighing 454 g each were treated with mineral oil at rates of 50, 100, 200, 400, and 600 ppm and grain dust...

Jones, David Don

1986-01-01T23:59:59.000Z

115

E-Print Network 3.0 - aerosol-to-liquid particle extraction Sample...  

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

XXXI Houston, March 2000 SIMS ISOTOPIC ANALYSIS OF INTERPLANETARY DUST FROM SPACE-EXPOSED AEROGEL. Summary: the captured residues. Extraction of particles. In the first step of the...

116

E-Print Network 3.0 - air-breathing direct methanol Sample Search...  

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

Res. 2005; 29:10411050 Summary: , U.S.A. SUMMARY An 8-cell air-breathing direct methanol fuel cell (DMFC) stack with the active area... of an air-breathing direct methanol fuel...

117

CT-PET Landmark-based Lung Registration Using a Dynamic Breathing Model S. Chambon1  

E-Print Network [OSTI]

CT-PET Landmark-based Lung Registration Using a Dynamic Breathing Model S. Chambon1 , A. Moreno1-based registration of CT (at two different instants of the breathing cycle, intermediate expirations) and PET images in order to simulate the instant in the breathing cycle most similar to the PET image and guarantee

Paris-Sud XI, Université de

118

On the Evolution of Dust Mineralogy, From Protoplanetary Disks to Planetary Systems  

E-Print Network [OSTI]

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...

Oliveira, Isa; Pontoppidan, Klaus M; van Dishoeck, Ewine F; Augereau, Jean-Charles; Merin, Bruno

2011-01-01T23:59:59.000Z

119

Vacuum friction in rotating particles  

E-Print Network [OSTI]

We study the frictional torque acting on particles rotating in empty space. At zero temperature, vacuum friction transforms mechanical energy into light emission and produces particle heating. However, particle cooling relative to the environment occurs at finite temperatures and low rotation velocities. Radiation emission is boosted and its spectrum significantly departed from a hot-body emission profile as the velocity increases. Stopping times ranging from hours to billions of years are predicted for materials, particle sizes, and temperatures accessible to experiment. Implications for the behavior of cosmic dust are discussed.

A. Manjavacas; F. J. García de Abajo

2010-09-21T23:59:59.000Z

120

INTRODUCTION Insects breathe using a tracheal respiratory system. The tracheal  

E-Print Network [OSTI]

2293 INTRODUCTION Insects breathe using a tracheal respiratory system. The tracheal system consists of the spiracular valves convectively deliver oxygen to the tissues. The tracheal respiratory system is efficient flow through the tracheal system (Harrison, 2009). During hypoxia, abdominal pumping often increases

Socha, Jake

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


121

24th April 2008 A breath of fresh air  

E-Print Network [OSTI]

and energy · the health, well-being and long term sustainability of rural communities; and · developing: rural-urban interface; future-proofing; waste; energy; water. #12;Innovation Platform - Low Impact24th April 2008 A breath of fresh air Rural Research and Strategy Partnership "Leveraging the SE

122

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

E-Print Network [OSTI]

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

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

2011-01-01T23:59:59.000Z

123

PROPERTIES OF NEWLY FORMED DUST GRAINS IN THE LUMINOUS TYPE IIn SUPERNOVA 2010jl  

SciTech Connect (OSTI)

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.

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

124

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

SciTech Connect (OSTI)

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

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

2011-11-15T23:59:59.000Z

125

Mineral Dust Entrainment and Deposition (DEAD) model: Description and 1990s dust climatology  

E-Print Network [OSTI]

DUST MODEL AND 1990S CLIMATOLOGY Table 5. Trace MetalDUST MODEL AND 1990S CLIMATOLOGY Figure 7. Predicted andDUST MODEL AND 1990S CLIMATOLOGY Mahowald, N. , K. Kohfeld,

Zender, Charles S; Bian, H.; Newman, D.

2003-01-01T23:59:59.000Z

126

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...

127

Simulation of dust streaming in toroidal traps: Stationary flows  

SciTech Connect (OSTI)

Molecular-dynamic simulations were performed to study dust motion in a toroidal trap under the influence of the ion drag force driven by a Hall motion of the ions in E x B direction, gravity, inter-particle forces, and friction with the neutral gas. This article is focused on the inhomogeneous stationary streaming motion. Depending on the strength of friction, the spontaneous formation of a stationary shock or a spatial bifurcation into a fast flow and a slow vortex flow is observed. In the quiescent streaming region, the particle flow features a shell structure which undergoes a structural phase transition along the flow direction.

Reichstein, Torben; Piel, Alexander [IEAP, Christian-Albrechts-Universitaet, D-24098 Kiel (Germany)

2011-08-15T23:59:59.000Z

128

Techniques For Injection Of Pre-Charaterized Dust Into The Scrape Off Layer Of Fusion Plasma  

SciTech Connect (OSTI)

Introduction of micron-sized dust into the scrape-off layer (SOL) of a plasma has recently found many applications aimed primarily at determining dust behavior in future fusion reactors. The dust particles are typically composed of materials intrinsic to a fusion reactor. On DIII-D and TEXTOR carbon dust has been introduced into the SOL using a probe inserted from below into the divertor region. On NSTX, both Li and tungsten dust have been dropped from the top of the machine into the SOL throughout the duration of a discharge, by utilizing a vibrating piezoelectric based particle dropper. The original particle dropper was developed to inject passivated Li powder {approx} 40 {mu}m in diameter into the SOL to enhance plasma performance. A simplified version of the dropper was developed to introduce trace amounts of tungsten powder for only a few discharges, thus not requiring a large powder reservoir. The particles emit visible light from plasma interactions and can be tracked by either spectroscopic means or by fast frame rate visible cameras. This data can then be compared with dust transport codes such as DUSTT to make predictions of dust behavior in next-step devices such as ITER. For complete modeling results, it is desired to be able to inject pre-characterized dust particles in the SOL at various known poloidal locations, including near the vessel midplane. Purely mechanical methods of injecting particles are presently being studied using a modified piezoelectric-based powder dropper as a particle source and one of several piezo-based transducers to deflect the particles into the SOL. Vibrating piezo fans operating at 60 Hz with a deflection of {+-}2.5 cm can impart a significant horizontal boost in velocity. The highest injection velocities are expected from rotating paddle wheels capable of injecting particles at 10's of meters per second depending primarily on the rotation velocity and diameter of the wheel. Several injection concepts have been tested and will be discussed below.

Roquemore, A. L.; John, B.; Friesen, F.; Hartzfeld, K.; Mansfield, D. K.

2011-07-21T23:59:59.000Z

129

DUST GRAIN EVOLUTION IN SPATIALLY RESOLVED T TAURI BINARIES  

SciTech Connect (OSTI)

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.

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

130

Coal cutting research slashes dust  

SciTech Connect (OSTI)

US Bureau of Mines' research projects aimed at the reduction of coal dust during coal cutting operations are described. These include an investigation of the effects of conical bit wear on respirable dust generation, energy and cutting forces; the determination of the best conical bit mount condition to increase life by enhancing bit rotation; a comparison between chisel- and conical-type cutters. In order to establish a suitable homogeneous reference material for cutting experiments, a synthetic coal with a plaster base is being developed.

Roepke, W.W.

1983-10-01T23:59:59.000Z

131

Nonlinear dust acoustic waves and shocks  

SciTech Connect (OSTI)

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.

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

132

Using Reconstructed Dust Climatology to Study the Impacts of Martian Dust Storms on Dynamics  

E-Print Network [OSTI]

Using Reconstructed Dust Climatology to Study the Impacts of Martian Dust Storms on Dynamics L@atm.ox.ac.uk) Abstract We have reconstructed the climatology of the dust on Mars using available retrievals and estimates) a reconstruction of the dust optical depth climatology based on weighted gridding for Martian years 24

Cambridge, University of

133

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

E-Print Network [OSTI]

Triaxial TestsTests Direct Shear TestsDirect Shear Tests Clean and Coal Dust Fouled Ballast BehaviorClean1 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 Dust

Barkan, Christopher P.L.

134

Adding coal dust to coal batch  

SciTech Connect (OSTI)

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

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

2009-05-15T23:59:59.000Z

135

TITLE: Identification of Possible Interstellar Dust Impact Craters on Stardust Foil I033N,1 P43A. Extraterrestrial Dust: Laboratory Analysis of Mission-Returned Samples and  

E-Print Network [OSTI]

a particle that impacted the spacecraft's solar panels. TEM/EDS analysis determined the presence of solar on Stardust Foil I033N,1 SESSION TYPE: Poster; SESSION TITLE: P43A. Extraterrestrial Dust: Laboratory Analysis. Contamination was monitored according to the ISPE protocol: four 4 µm ! 3 µm areas of C layers of different

136

Prediction of the In-Situ Dust Measurements of the Stardust Mission to Comet 81P/Wild 2  

E-Print Network [OSTI]

We predict the amount of cometary, interplanetary, and interstellar cosmic dust that is to be measured by the Cometary and Interstellar Dust Analyzer (CIDA) and the aerogel collector on-board the Stardust spacecraft during its fly-by of comet P/Wild 2 and during the interplanetary cruise phase. We give the dust flux on the spacecraft during the encounter with the comet using both, a radially symmetric and an axially symmetric coma model. At closest approach, we predict a total dust flux of $10^{6.0} m^{-2} s^{-1}$ for the radially symmetric case and $10^{6.5} m^{-2} s^{-1}$ for the axially symmetric case. This prediction is based on an observation of the comet at a heliocentric distance of $1.7 {\\rm AU}$. We reproduce the measurements of the Giotto and VEGA missions to comet P/Halley using the same model as for the Stardust predictions. The planned measurements of {\\em interstellar} dust by Stardust have been triggered by the discovery of interstellar dust impacts in the data collected by the Ulysses and Galileo dust detector. Using the Ulysses and Galileo measurements we predict that 25 interstellar particles, mainly with masses of about $10^{-12} g$, will hit the target of the CIDA experiment. The interstellar side of the aerogel collector will contain 120 interstellar particles, 40 of which with sizes greater than $1 \\mu m$. We furthermore investigate the ``contamination'' of the CIDA and collector measurements by interplanetary particles during the cruise phase.

Markus Landgraf; Michael Müller; Eberhard Grün

1999-04-15T23:59:59.000Z

137

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

SciTech Connect (OSTI)

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.

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

138

E-Print Network 3.0 - air breathing propulsion Sample Search...  

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

give oxygen. EYE EXPOSURE: Assure adequate... -contained breathing apparatus, rubber boots, and heavy rubber gloves. METHODS FOR CLEANING UP: Absorb ... Source: Cohen, Robert E....

139

E-Print Network 3.0 - air breathing direct Sample Search Results  

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

give oxygen. EYE EXPOSURE: Assure adequate... -contained breathing apparatus, rubber boots, and heavy rubber gloves. METHODS FOR CLEANING UP: Absorb ... Source: Cohen, Robert E....

140

E-Print Network 3.0 - advanced air breathing Sample Search Results  

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

give oxygen. EYE EXPOSURE: Assure adequate... -contained breathing apparatus, rubber boots, and heavy rubber gloves. METHODS FOR CLEANING UP: Absorb ... Source: Cohen, Robert E....

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


141

E-Print Network 3.0 - acid breath tests Sample Search Results  

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

and protective... PRECAUTION(S) Wear self-contained breathing apparatus, rubber boots, and heavy rubber ... Source: Choi, Kyu Yong - Department of Chemical Engineering and...

142

E-Print Network 3.0 - air-breathing pulse detonation Sample Search...  

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

air-breathing PDE ... Source: Powers, Joseph M.- Department of Aerospace and Mechanical Engineering, University of Notre Dame Collection: Engineering 2 Proceedings of the...

143

Molecular Hydrogen Emission from Protoplanetary Disks II. Effects of X-ray Irradiation and Dust Evolution  

E-Print Network [OSTI]

Detailed models for the density and temperature profiles of gas and dust in protoplanetary disks are constructed by taking into account X-ray and ultraviolet (UV) irradiation from a central T Tauri star, as well as dust size growth and settling toward the disk midplane. The spatial and size distributions of dust grains in the disks are numerically computed by solving the coagulation equation for settling dust particles. The level populations and line emission of molecular hydrogen are calculated using the derived physical structure of the disks. X-ray irradiation is the dominant heating source of the gas in the inner disk region and in the surface layer, while the far UV heating dominates otherwise. If the central star has strong X-ray and weak UV radiation, the H2 level populations are controlled by X-ray pumping, and the X-ray induced transition lines could be observable. If the UV irradiation is strong, the level populations are controlled by thermal collisions or UV pumping, depending on the properties of the dust grains in the disks. As the dust particles evolve in the disks, the gas temperature at the disk surface drops because the grain photoelectric heating becomes less efficient, while the UV radiation fields become stronger due to the decrease of grain opacity. This makes the H2 level populations change from local thermodynamic equilibrium (LTE) to non-LTE distributions, which results in changes to the line ratios of H2 emission. Our results suggest that dust evolution in protoplanetary disks could be observable through the H2 line ratios. The emission lines are strong from disks irradiated by strong UV and X-rays and possessing small dust grains; such disks will be good targets in which to observe H2 emission.

H. Nomura; Y. Aikawa; M. Tsujimoto; Y. Nakagawa; T. J. Millar

2007-02-01T23:59:59.000Z

144

THE REBOUND CONDITION OF DUST AGGREGATES REVEALED BY NUMERICAL SIMULATION OF THEIR COLLISIONS  

SciTech Connect (OSTI)

Collisional growth of dust aggregates is a plausible root of planetesimals forming in protoplanetary disks. However, a rebound of colliding dust aggregates prevents dust from growing into planetesimals. In fact, rebounding aggregates are observed in laboratory experiments but not in previous numerical simulations. Therefore, the condition of rebound between dust aggregates should be clarified to better understand the processes of dust growth and planetesimal formation. We have carried out numerical simulations of aggregate collisions for various types of aggregates and succeeded in reproducing a rebound of colliding aggregates under specific conditions. Our finding is that in the rebound process, the key factor of the aggregate structure is the coordination number, namely, the number of particles in contact with a particle. A rebound is governed by the energy dissipation along with restructuring of the aggregates and a large coordination number inhibits the restructuring at collisions. Results of our numerical simulation for various aggregates indicate that they stick to each other when the mean coordination number is less than 6, regardless of their materials and structures, as long as their collision velocity is less than the critical velocity for fragmentation. This criterion of the coordination number would correspond to a filling factor of {approx}0.3, which is somewhat larger than that reported in laboratory experiments. In protoplanetary disks, dust aggregates are expected to have low bulk densities (<0.1 g cm{sup -3}) during their growth, which would prevent dust aggregates from rebounding. This result supports the formation of planetesimals with direct dust growth in protoplanetary disks.

Wada, Koji [Planetary Exploration Research Center, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016 (Japan); Tanaka, Hidekazu; Yamamoto, Tetsuo [Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819 (Japan); Suyama, Toru [Nagano City Museum, Hachimanpara Historic Park, Oshimada, Nagano 381-2212 (Japan); Kimura, Hiroshi, E-mail: wada@perc.it-chiba.ac.jp [Center for Planetary Science (CPS), Chuo-ku Minatojima Minamimachi 7-1-48, Kobe 650-0047 (Japan)

2011-08-10T23:59:59.000Z

145

ORIGIN OF DUST AROUND V1309 SCO  

SciTech Connect (OSTI)

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.

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

146

A novel aspect of dust in plasma  

SciTech Connect (OSTI)

Nonlinear screening of the dust grains immersed in a homogenous fully ionized electron-ion plasma is investigated. Assuming conservation of entropy, an important relation is obtained between the maximum potential (and therefore the charge) of the dust grain and the temperature of the electrons. The Thomas-Fermi equation is derived for the potential of a dust grain in a nondegenerate plasma suggesting the existence of dust atom with a well defined atomic radius. Furthermore, based on the Born-Oppenheimer approximation, the notion of a dust-grain molecule is introduced in which the protons act like a kind of 'glue' which binds two negatively charged dust grains together, and the motion of the grains have little influence on that binding force. Finally, considering the weak interaction between the proton clouds of two dust grains, an expression of exchange energy is obtained.

Tsintsadze, N.L.; Murtaza, G.; Ehsan, Z. [Department of Plasma Physics, Tbilisi State University (Georgia); National Centre for Mathematics and Salam Chair in Physics, G.C. University Lahore, 54000 (Pakistan); National Centre for Mathematics and Salam Chair in Physics, G.C. University Lahore, 54000 (Pakistan)

2006-02-15T23:59:59.000Z

147

Air-Breathing Fuel Cell Stack - Energy Innovation Portal  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAbout the BuildingInnovation 2011OversupplyPlasmaAir-Breathing Fuel Cell

148

Does variation in mineral composition alter the short-wave light scattering properties of desert dust aerosol?  

E-Print Network [OSTI]

retrievals of mineral dust aerosol from space by visible and near-infrared radiometers. Errors in aerosol depth in deserts and the surrounding regions during periods of high wind. Long range transport of desert particles into the air [6] (wind alone does not have sufficient energy to remove particles from the surface

Oxford, University of

149

SIZE AND DENSITY ESTIMATION FROM IMPACT TRACK MORPHOLOGY IN SILICA AEROGEL: APPLICATION TO DUST FROM COMET 81P/WILD 2  

SciTech Connect (OSTI)

A large number of cometary dust particles were captured with low-density silica aerogel during the NASA Stardust mission. The dust particles penetrated into the aerogel and formed various track shapes. To estimate the properties of the dust particles, such as density and size, based on the morphology of the tracks, we carried out systematic experiments testing impacts into low-density aerogel at 6 km s{sup -1} using projectiles of various sizes and densities. We found that the maximum track diameter and the ratio of the track length to the maximum track diameter in aerogel are good indicators of projectile size and density, respectively. Based on these results, we estimated the size and density of individual dust particles from comet 81P/Wild 2. The average density of the 'fluffy' dust particles and the bulk density of all dust particles were obtained as 0.35 {+-} 0.07 and 0.49 {+-} 0.18 g cm{sup -3}, respectively. These statistical data provided the content of monolithic and coarse grains in the Stardust particles, {approx}30 wt%. Combining this result with some mid-infrared observational data, we found that the content of crystalline silicates is {approx}50 wt% or more of non-volatile material.

Niimi, Rei; Tsuchiyama, Akira [Department of Earth and Space Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Kadono, Toshihiko [Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871 (Japan); Okudaira, Kyoko [Office for Planning and Management, The University of Aizu, Aizuwakamatsu, Fukushima 965-8580 (Japan); Hasegawa, Sunao; Tabata, Makoto [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 252-5210 (Japan); Watanabe, Takayuki; Yagishita, Masahito [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, Nagatsuta, Yokohama 226-8502 (Japan); Machii, Nagisa; Nakamura, Akiko M. [Department of Earth and Planetary Sciences, Kobe University, Nada, Kobe 657-8501 (Japan); Uesugi, Kentaro; Takeuchi, Akihisa [Synchrotron Radiation Research Institute, SPring-8, Sayo, Hyogo 679-5198 (Japan); Nakano, Tsukasa, E-mail: kadonot@ile.osaka-u.ac.jp [Geological Survey of Japan, Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8567 (Japan)

2012-01-01T23:59:59.000Z

150

asian dust particles: Topics by E-print Network  

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

and meteorological parameters in the Gobi region indicated that invasion of polar cold air played an important role climate indices that are appropriate for the scale of...

151

Coal cutting research slashes dust  

SciTech Connect (OSTI)

The Coal-Cutting Technology Group at the Bureau of Mine's Twin Cities Research Center is investigating ways to reduce primary dust generated by coal cutting. The progression of research within the program is from fundamental laboratory research, to fundamental field research, to field concept verification. Then the Bureau recommends warranted changes and/or prototype development to industry. Currently the Cutting Technology Group has several projects in each phase of research. The Bureau's current fundamental studies of bit characteristics are directed to determining the effects of conical bit wear on primary respirable dust generation, energy, and cutting forces; establishing best conical bit mount condition to increase life by enhancing bit rotation; and comparing chisel-type cutters to conical-type cutters. Additionally, to establish a suitable homogeneous reference material for cutting experiments, a synthetic coal with a plaster base is being developed.

Roepke, W.W.

1983-10-01T23:59:59.000Z

152

Coal cutting research slashes dust  

SciTech Connect (OSTI)

The Coal-Cutting Technology Group at the Bureau of Mines Twin Cities (MN) Research Center is investigating ways to reduce primary dust generated by coal cutting. The progression of research within the program is from fundamental laboratory research, to fundamental field research, to field concept verification. Then the Bureau recommends warranted changes and/or prototype development to industry. Currently the group has several projects in each phase of research. The Bureau's current fundamental studies of bit characteristics are directed toward determining the effects of conical bit wear on primary respirable dust generation, energy, and cutting forces; establishing best conical bit mount condition to increase life by enhancing bit rotation; and comparing chisel-type cutters to conical-type cutters. Additionally, to establish a suitable homogeneous reference material for cutting experiments, a synthetic coal with a plaster base is being developed.

Roepke, W.W.

1983-10-01T23:59:59.000Z

153

SAMPLING AND MASS SPECTROMETRY APPROACHES FOR THE DETECTION OF DRUGS AND FOREIGN CONTAMINANTS IN BREATH FOR HOMELAND SECURITY APPLICATIONS  

SciTech Connect (OSTI)

Homeland security relies heavily on analytical chemistry to identify suspicious materials and persons. Traditionally this role has focused on attribution, determining the type and origin of an explosive, for example. But as technology advances, analytical chemistry can and will play an important role in the prevention and preemption of terrorist attacks. More sensitive and selective detection techniques can allow suspicious materials and persons to be identified even before a final destructive product is made. The work presented herein focuses on the use of commercial and novel detection techniques for application to the prevention of terrorist activities. Although drugs are not commonly thought of when discussing terrorism, narcoterrorism has become a significant threat in the 21st century. The role of the drug trade in the funding of terrorist groups is prevalent; thus, reducing the trafficking of illegal drugs can play a role in the prevention of terrorism by cutting off much needed funding. To do so, sensitive, specific, and robust analytical equipment is needed to quickly identify a suspected drug sample no matter what matrix it is in. Single Particle Aerosol Mass Spectrometry (SPAMS) is a novel technique that has previously been applied to biological and chemical detection. The current work applies SPAMS to drug analysis, identifying the active ingredients in single component, multi-component, and multi-tablet drug samples in a relatively non-destructive manner. In order to do so, a sampling apparatus was created to allow particle generation from drug tablets with on-line introduction to the SPAMS instrument. Rules trees were developed to automate the identification of drug samples on a single particle basis. A novel analytical scheme was also developed to identify suspect individuals based on chemical signatures in human breath. Human breath was sampled using an RTube{trademark} and the trace volatile organic compounds (VOCs) were preconcentrated using solid phase microextraction (SPME) and identified using gas chromatography - mass spectrometry (GC-MS). Modifications to the sampling apparatus allowed for increased VOC collection efficiency, and reduced the time of sampling and analysis by over 25%. The VOCs are present in breath due to either endogenous production, or exposure to an external source through absorption, inhalation, or ingestion. Detection of these exogenous chemicals can provide information on the prior location and activities of the subject. Breath samples collected before and after exposure in a hardware store and nail salon were analyzed to investigate the prior location of a subject; breath samples collected before and after oral exposure to terpenes and terpenoid compounds, pseudoephedrine, and inhalation exposure to hexamine and other explosive related compounds were analyzed to investigate the prior activity of a subject. The elimination of such compounds from the body was also monitored. In application, this technique may provide an early warning system to identify persons of interest in the prevention and preemption stages of homeland security.

Martin, A N

2009-01-27T23:59:59.000Z

154

Impact of Particle Generation Method on the Apparent Hygroscopicity of Insoluble Mineral Particles  

SciTech Connect (OSTI)

Atmospheric mineral dust particles represent a major component of tropospheric aerosol mass and provide a reactive surface for heterogeneous reactions with trace atmospheric gases (Dentener et al. 1996).Heterogeneous processes alter the chemical balance of the atmosphere and also modify the physicochemical properties of mineral dust particles (Bauer et al. 2004). Organic and inorganic vapors can react with or partition to dust particles and alter their chemical composition (Al-Hosney et al. 2005; Laskin et al. 2005a, 2005b; Liu et al. 2008; Sullivan et al. 2007, 2009a; Sullivan and Prather 2007; Usher et al. 2003). Calcite (CaCO3) is one of the most reactive components of mineral dust, readily reacting with acidic gases. The fraction of CaCO3 in total dust mineralogy displays large variations between desert regions and other regions of the world as well as between individual mineral particles (Claquin et al. 1999; Jeong 2008; Laskin et al. 2005b; Sullivan et al. 2007). Through reactions with acidic gases CaCO3 can be converted to soluble hygroscopic products including CaCl2 and Ca(NO3)2, and sparingly soluble, non-hygroscopic products including CaSO4 and CaC2O4 (Krueger et al. 2004; Liu et al. 2008; Sullivan et al. 2009a, 2009b).

Sullivan, Ryan; Moore, Meagan J.; Petters, Markus D.; Kreidenweis, Sonia M.; Qafoku, Odeta; Laskin, Alexander; Roberts, Greg C.; Prather, Kimberly A.

2010-07-28T23:59:59.000Z

155

Astrophysics of Dust in Cold Clouds  

E-Print Network [OSTI]

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.

B. T. Draine

2003-04-28T23:59:59.000Z

156

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

E-Print Network [OSTI]

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

157

HIGH FLUENCE SYNCHROTRON RADIATION MICROPROBE EFFECTS ON STARDUST INTERSTELLAR DUST CANDIDATES. A. Simionovici1  

E-Print Network [OSTI]

to the interstellar dust stream. Analysis of these candidates from both low density aerogel capture cells and Al]. The aerogel samples were analyzed in situ in their pico- keystones by synchrotron radiation focused microprobe thickness slabs of aerogel containing the IS particles for further analysis. The ISPE team has implemented

Nittler, Larry R.

158

NNWSI PROJECT ELEMENT WBS-1.2.6.9.4.6.1.B INTERIM REPORT ON DUST CONTROL PROPOSALS  

SciTech Connect (OSTI)

This report presents interim findings of studies conducted to evaluate dust control equipment during prototype drilling. Based on available data on silica content, type, particle size, and on proposed dry drilling operations, it is estimated that allowable exposures to free silica will range from 0.07 to 1.5 mg/cu meter. They have concluded that airborne concentrations of dust may approach or exceed these values during normal operations, based on studies conducted as part of this task.

D.J. Burton

2005-09-06T23:59:59.000Z

159

Experimental evaluation of cell temperature effects on miniature, air-breathing PEM fuel cells  

E-Print Network [OSTI]

Experimental evaluation of cell temperature effects on miniature, air-breathing PEM fuel cells Z June 2011 Available online 14 June 2011 Keywords: Air-breathing PEM fuel cell Temperature effects Air) fuel cells is investi- gated using polarization and impedance spectroscopy. Three active area sizes

Lee, Tonghun

160

Excitonic effects on radial breathing mode intensity of single wall carbon nanotubes  

E-Print Network [OSTI]

Excitonic effects on radial breathing mode intensity of single wall carbon nanotubes Kentaro Satoa Abstract We develop exciton-photon and exciton-phonon interaction matrix elements for sin- gle wall carbon- culate resonance Raman intensity for radial breathing mode as a function of diameter and chiral angle

Maruyama, Shigeo

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


161

The strength of the radial-breathing mode in single-walled carbon nanotubes  

E-Print Network [OSTI]

The strength of the radial-breathing mode in single-walled carbon nanotubes M. Machón , S. Reich of the absolute Raman cross section of the radial breathing mode (RBM) of single-walled carbon nanotubes. We compare our calculations to measurements of the absolute Raman cross section of individual nanotubes

Nabben, Reinhard

162

MODELS FOR AN ANESTHESIA BREATHING CIRCUIT Paul E. Bigeleisen + and Margaret Cheney ++  

E-Print Network [OSTI]

MODELS FOR AN ANESTHESIA BREATHING CIRCUIT Paul E. Bigeleisen + and Margaret Cheney ++ + Department of Anesthesia, St. Paul Ramsey Medical Center, St. Paul, MN 55101; per­ manent address: Department­4824. ABSTRACT This paper presents a mathematical model of a semi­closed anesthesia breathing cir­ cuit

Cheney, Margaret

163

Volumetric measurements of a spatially growing dust acoustic wave  

SciTech Connect (OSTI)

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

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

2012-11-15T23:59:59.000Z

164

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

E-Print Network [OSTI]

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...

Fang, Guangyang

2012-07-16T23:59:59.000Z

165

The dust, planetesimals and planets of HD 38529  

E-Print Network [OSTI]

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).

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

166

GRAIN SORTING IN COMETARY DUST FROM THE OUTER SOLAR NEBULA  

SciTech Connect (OSTI)

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

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

2012-12-01T23:59:59.000Z

167

Dust and gas in active galaxies  

E-Print Network [OSTI]

There are strong evidences which favour the existence of dust in active galaxies. Understanding the way in which dust interacts with the radiation and influences the physical conditions of the gas is crucial if we want to learn about the nature of the central active nucleus and about the physical conditions of the ISM in such galaxies. Not taking into account such effects may lead us towards misleading interpretations. Many intriguing questions concerns to the nature and the existence of dust in active galaxies: for instance, under which conditions does the very hard ionizing continuum of an AGN allows the survival of dust grains? Is the composition and size distribution of the dust the same as in our local interstellar medium? How is dust distributed compared to the gas which is at least in part highly ionized by the central AGN? Does dust also exist in radio galaxies at very high redshifts? The work developed in this thesis tries to find answers to some of these questions, through a detailed theoretical and observational research of the mechanisms which control the interaction of dust with the radiation and with the ions. The observable effects of the dust on the emission line spectrum are also analyzed in detail. The final goal has been to give clues about more general questions: origin of the emitting gas, ionization mechanisms, geometry, connection between low and high redshift active galaxies or the validity of the unification scenario. This thesis tries, in summary, to provide a clearer understanding of active galaxies in general.

M. Villar-Martin

1996-05-21T23:59:59.000Z

168

Health Benefits of Particle Filtration  

SciTech Connect (OSTI)

The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percentage improvement in health outcomes is typically modest, e.g., 7percent to 25percent. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air.

Fisk, William J.

2013-10-01T23:59:59.000Z

169

Health Benefits of Particle Filtration  

SciTech Connect (OSTI)

The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also, reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percent age improvement in health outcomes is typically modest, for example, 7percent to 25percent. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air.

Fisk, William J.

2013-10-01T23:59:59.000Z

170

Determination of Dusty Particle Charge Taking into Account Ion Drag  

SciTech Connect (OSTI)

This work is devoted to the experimental estimation of charge of dust particle that levitates in the stratum of dc glow discharge. Particle charge is determined on the basis of the balance between ion drag force, gravitational and electric forces. Electric force is obtained from the axial distribution of the light intensity of strata.

Ramazanov, T. S.; Dosbolayev, M. K.; Jumabekov, A. N.; Amangaliyeva, R. Zh.; Orazbayev, S. A. [al-Farabi Kazakh National University, IETP, 96a Tole Bi St., Almaty 050012 (Kazakhstan); Petrov, O. F.; Antipov, S. N. [Joint Institute for High Temperatures of RAS, 13/19 Izhorskaya, Moscow 125412 (Russian Federation)

2008-09-07T23:59:59.000Z

171

Particle Astrophysics  

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

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

172

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...

173

Dust-acoustic filamentation of a current-driven dusty plasma  

SciTech Connect (OSTI)

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

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

2011-06-15T23:59:59.000Z

174

Dust filtration at gap edges: Implications for the spectral energy distributions of discs with embedded planets  

E-Print Network [OSTI]

The spectral energy distributions (SEDs) of some T Tauri stars display a deficit of near-IR flux that could be a consequence of an embedded Jupiter-mass planet partially clearing an inner hole in the circumstellar disc. Here, we use two-dimensional numerical simulations of the planet-disc interaction, in concert with simple models for the dust dynamics, to quantify how a planet influences the dust at different radii within the disc. We show that pressure gradients at the outer edge of the gap cleared by the planet act as a filter - letting particles smaller than a critical size through to the inner disc while holding back larger particles in the outer disc. The critical particle size depends upon the disc properties, but is typically of the order of 10 microns. This filtration process will lead to discontinuous grain populations across the planet's orbital radius, with small grains in the inner disc and an outer population of larger grains. We show that this type of dust population is qualitatively consistent with SED modelling of systems that have optically thin inner holes in their circumstellar discs. This process can also produce a very large gas-to-dust ratio in the inner disc, potentially explaining those systems with optically thin inner cavities that still have relatively high accretion rates.

W. K. M. Rice; Philip J. Armitage; Kenneth Wood; Giuseppe Lodato

2006-09-29T23:59:59.000Z

175

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

E-Print Network [OSTI]

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

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

2013-01-01T23:59:59.000Z

176

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

E-Print Network [OSTI]

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

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

2013-01-24T23:59:59.000Z

177

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

SciTech Connect (OSTI)

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.

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

178

Metal Dusting of Heat-Resistant Alloys  

E-Print Network [OSTI]

Metal dusting leads to disintegration of such alloys as iron and nickel-based into a “dust” of particulate metal, metal carbide, carbon, and/or oxide. It occurs in strongly carburising environments at 400-900°C. Literature survey has shown...

Al-Meshari, Abdulaziz I

179

Rigidly rotating cylinders of charged dust  

E-Print Network [OSTI]

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.

B. V. Ivanov

2002-07-02T23:59:59.000Z

180

Circumstellar Dust Shells Detlef Schonberner, Matthias Steffen  

E-Print Network [OSTI]

Circumstellar Dust Shells Detlef Sch¨onberner, Matthias Steffen This research project is concerned spectra and intensity maps computed from the resulting time­dependent wind models can be compared directly as spherical grains of amor­ phous carbon with a radius of 0.05 ¯m, the adopted dust­ to­gas ratio being 1

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


181

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,...

182

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...

183

The cardiac output response and the oxygen cost of increased work of breathing  

E-Print Network [OSTI]

. By back extrapolation from the measured values, Liljestrand estimated the oxygen cost of breathing at rest to be about 0. 5 ml Op per liter of ventilation. This resting value was later substantiated by Neilsen ( 1936). In addition, Nei lsen also...-smokers and free from any 20 WORlC 8. 1750 cal VOLUME 1142 el s M*X IHSP PRE -8. 48 cwH20 MAX EXP PRE 2 ' 22 cMH2Q Figure 4. Work of breathing measurement of a single breath at rest. The shaded and black areas to the left of the base pressure (-4. 5 cm...

Krause, Kevin Michael

1989-01-01T23:59:59.000Z

184

Dust Emission from the Perseus Molecular Cloud  

E-Print Network [OSTI]

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.

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

2008-05-27T23:59:59.000Z

185

Linear and nonlinear dust acoustic waves in an inhomogeneous magnetized dusty plasma with nonextensive electrons  

SciTech Connect (OSTI)

The propagation of both linear and nonlinear dust acoustic waves (DAWs) in an inhomogeneous magnetized collisional and warm dusty plasma (DP) consisting of Boltzmann ions, nonextensive electrons, and inertial dust particles is investigated. The number density gradients of all DP components besides the inhomogeneities of electrostatic potential and the initial dust fluid velocity are taken into account. The linear dispersion relation and a nonlinear modified Zakharov-Kusnetsov (MZK) equation governing the propagation of the three-dimensional DAWs are derived. The analytical solution of the MZK reveals the creation of both compressive and rarefactive DAW solitons in the proposed model. It is found that the inhomogeneity dimension parameter and the electron nonextensive parameter affect significantly the nonlinear DAW's amplitude, width, and Mach number. The relations of our findings with some astrophysical situations have been given.

El-Taibany, W. F., E-mail: eltaibany@du.edu.eg, E-mail: eltaibany@hotmail.com; Selim, M. M.; Al-Abbasy, O. M. [Department of Physics, Faculty of Science, Damietta University, New Damietta P. O. 34517 (Egypt); El-Bedwehy, N. A., E-mail: nab-elbedwehy@yahoo.com [Department of Mathematics, Faculty of Science, Damietta University, New Damietta P. O. 34517 (Egypt)

2014-07-15T23:59:59.000Z

186

A fast ascent trajectory optimization method for hypersonic air-breathing vehicles.  

E-Print Network [OSTI]

??The objective of this dissertation is to investigate a fast and reliable method to generate three-dimensional optimal ascent trajectories for hypersonic air-breathing vehicles. The problem… (more)

Murillo, Oscar Jaime

2010-01-01T23:59:59.000Z

187

E-Print Network 3.0 - air breathing fish Sample Search Results  

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

fish Search Powered by Explorit Topic List Advanced Search Sample search results for: air breathing fish Page: << < 1 2 3 4 5 > >> 1 The effect of apparent predationrisk on the...

188

E-Print Network 3.0 - air-breathing fish channa Sample Search...  

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

fish channa Search Powered by Explorit Topic List Advanced Search Sample search results for: air-breathing fish channa Page: << < 1 2 3 4 5 > >> 1 The effect of swimming depth on...

189

E-Print Network 3.0 - alter breathing cardiovascular Sample Search...  

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

Sample search results for: alter breathing cardiovascular Page: << < 1 2 3 4 5 > >> 1 Heart rate dynamics during three forms of meditation C.-K. Penga,*, Isaac C. Henrya Summary:...

190

Particle separation  

DOE Patents [OSTI]

Embodiments of a method for selecting particles, such as based on their morphology, is disclosed. In a particular example, the particles are charged and acquire different amounts of charge, or have different charge distributions, based on their morphology. The particles are then sorted based on their flow properties. In a specific example, the particles are sorted using a differential mobility analyzer, which sorts particles, at least in part, based on their electrical mobility. Given a population of particles with similar electrical mobilities, the disclosed process can be used to sort particles based on the net charge carried by the particle, and thus, given the relationship between charge and morphology, separate the particles based on their morphology.

Moosmuller, Hans (Reno, NV); Chakrabarty, Rajan K. (Reno, NV); Arnott, W. Patrick (Reno, NV)

2011-04-26T23:59:59.000Z

191

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

SciTech Connect (OSTI)

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

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

2012-09-20T23:59:59.000Z

192

Respiratory Motion of The Heart and Positional Reproducibility Under Active Breathing Control  

SciTech Connect (OSTI)

Purpose: To reduce cardiotoxicity from breast radiotherapy (RT), innovative techniques are under investigation. Information about cardiac motion with respiration and positional reproducibility under active breathing control (ABC) is necessary to evaluate these techniques. Methods and Materials: Patients requiring loco-regional RT for breast cancer were scanned by computed tomography using an ABC device at various breath-hold states, before and during treatment. Ten patients were studied. For each patient, 12 datasets were analyzed. Mutual information-based regional rigid alignment was used to determine the magnitude and reproducibility of cardiac motion as a function of breathing state. For each scan session, motion was quantified by evaluating the displacement of a point along the left anterior descending artery (LAD) with respect to its position at end expiration. Long-term positional reproducibility was also assessed. Results: Displacement of the LAD was greatest in the inferior direction, moderate in the anterior direction, and lowest in the left-right direction. At shallow breathing states, the average displacement of LAD position was up to 6 mm in the inferior direction. The maximum displacement in any patient was 2.8 cm in the inferior direction, between expiration and deep-inspiration breath hold. At end expiration, the long-term reproducibility (SD) of the LAD position was 3 mm in the A-P, 6 mm in the S-I, and 4 mm in the L-R directions. At deep-inspiration breath hold, long-term reproducibility was 3 mm in the A-P, 7 mm in the S-I, and 3 mm in the L-R directions. Conclusions: These data demonstrate the extent of LAD displacement that occurs with shallow breathing and with deep-inspiration breath hold. This information may guide optimization studies considering the effects of respiratory motion and reproducibility of cardiac position on cardiac dose, both with and without ABC.

Jagsi, Reshma [Department of Radiation Oncology, University of Michigan, Ann Arbor, MI (United States); Moran, Jean M. [Department of Radiation Oncology, University of Michigan, Ann Arbor, MI (United States); Kessler, Marc L. [Department of Radiation Oncology, University of Michigan, Ann Arbor, MI (United States); Marsh, Robin B. C [Department of Radiation Oncology, University of Michigan, Ann Arbor, MI (United States); Balter, James M. [Department of Radiation Oncology, University of Michigan, Ann Arbor, MI (United States); Pierce, Lori J. [Department of Radiation Oncology, University of Michigan, Ann Arbor, MI (United States)]. E-mail: ljpierce@umich.edu

2007-05-01T23:59:59.000Z

193

Wave-Particle Duality and the Hamilton-Jacobi Equation  

E-Print Network [OSTI]

The Hamilton-Jacobi equation of relativistic quantum mechanics is revisited. The equation is shown to permit solutions in the form of breathers (oscillating/spinning solitons), displaying simultaneous particle-like and wave-like behavior. The de Broglie wave thus acquires a clear deterministic meaning of a wave-like excitation of the classical action function. The problem of quantization in terms of the breathing action function and the double-slit experiment are discussed.

Gregory I. Sivashinsky

2009-12-28T23:59:59.000Z

194

Silica dust control when drilling concrete Page 1 of 2  

E-Print Network [OSTI]

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

Knowles, David William

195

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

E-Print Network [OSTI]

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

Merlino, Robert L.

196

The gas temperature in circumstellar disks: effects of dust settling  

E-Print Network [OSTI]

The gas temperature in circumstellar disks: effects of dust settling F. Faas, G.J. van Zadelhoff, E distributions. The disk gas-temperature (T ¢¡¢£ ) is in general assumed to be equal to the dust-temperature (T¤¦¥ £ § ), due to collisions. Dust settling depends on both the gas and dust temperature. T

Zadelhoff, Gerd-Jan van

197

Morphological Investigations of Fibrogenic Action of Estonian Oil Shale Dust  

E-Print Network [OSTI]

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

V. A. Kung

198

Coal Fly Ash as a Source of Iron in Atmospheric Dust  

SciTech Connect (OSTI)

Anthropogenic coal fly ash aerosols may represent a significant source of bioavailable iron in the open ocean. Few measurements have been made to compare the solubility of atmospheric iron from anthropogenic aerosols and other sources. We report an investigation of the iron dissolution of three fly ash samples in acidic aqueous solutions and compare the solubilities with that of Arizona test dust, a reference material of mineral dust. The effects of pH, cloud processing, and solar irradiation on Fe solubility were explored. Similar to previously reported results on mineral dust, iron in aluminosilicate phases provide predominant dissolved iron compared with iron in oxides. Iron solubility of fly ash is higher than Arizona test dust, especially at the higher pH conditions investigated. Simulated atmospheric processing elevates iron solubility due to significant changes in the morphology aluminosilicate glass, a dominantly material in fly ash particle. Iron continuously releases into the aqueous solution as fly ash particles break up into smaller fragments. The assessment of dissolved atmospheric iron deposition fluxes, and their effect on the biogeochemistry at ocean surface should be constrained by taking into account the source, environment pH, Fe speciation, and solar radiation.

Chen, Haihan; Laskin, Alexander; Baltrusaitis, Jonas; Gorski, Christopher A.; Scherer, Michelle; Grassian, Vicki H.

2012-01-18T23:59:59.000Z

199

Studies on hydrogen plasma and dust charging in low-pressure filament discharge  

SciTech Connect (OSTI)

The effect of working gas pressure and dust charging on electron energy probability function has been studied for hydrogen plasma in a multi-dipole dusty plasma device. A cylindrical Langmuir probe is used to evaluate the plasma parameters and electron energy probability function (EEPF) for different working pressures. For lower energy range (below 10?eV), the EEPF follows a bi-Maxwellian shape at very low pressure (6 × 10{sup ?5}?mbar), while elevating the working pressure up to ?2 × 10{sup ?3} mbar, the shape of the EEPF transforms into a single Maxwellian. Some dip structures are observed at high energy range (??>?10?eV) in the EEPF of hydrogen plasma at all the working conditions. In presence of dust particles, it is observed that the shape of the EEPF changes due to the redistribution of the high and low-energy electron populations. Finally, the effect of working pressure on charge accumulation on dust particles is studied with the help of a Faraday cup and electrometer. From the observations, a strong influence of working pressure on plasma parameters, EEPF and dust charging is observed.

Kakati, B., E-mail: bharatkakati15@gmail.com; Kalita, D.; 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)

2014-08-15T23:59:59.000Z

200

Global coherence of dust density waves  

SciTech Connect (OSTI)

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.

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

2014-06-15T23:59:59.000Z

Note: This page contains sample records for the topic "breathe dust particles" from the National Library of EnergyBeta (NLEBeta).
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to obtain the most current and comprehensive results.


201

Surface acoustic wave dust deposition monitor  

DOE Patents [OSTI]

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.

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

1988-02-12T23:59:59.000Z

202

Structural features of bicomponent dust Coulomb balls formed by the superposition of fields of different origin in plasma  

SciTech Connect (OSTI)

A binary mixture of dust particles in plasma which are in an external electrostatic harmonic confining field as well as in the field consisting of gravitational, thermophoretic, and electrostatic force is simulated. The interparticle interaction is described by the Yukawa isotropic pair potential. The structural properties of the binary mixture of particles depending on composition are investigated. The segregation features of a system of particles of two species under the conditions of recent experiments on Coulomb ball formation are studied. It is shown that particles form a shell structure in which every shell contains only its own species of particles; in so doing, smaller-sized particles make up outer shells with respect to larger-sized particles. When the size difference between the particles becomes more and more pronounced, they are spatially separated up to the formation of two independent Coulomb balls.

Psakhie, S. G.; Zolnikov, K. P.; Kryzhevich, D. S.; Abdrashitov, A. V. [Institute of Strength Physics and Materials Science SB RAS, 634021, Tomsk, pr. Akademicheskii, 2/1 (Russian Federation); Skorentsev, L. F. [Siberian Physico-Technical Institute, 634050, Tomsk, pl. Novosobornaya, 1 (Russian Federation)

2008-05-15T23:59:59.000Z

203

Boll Weevil Control by Airplane Dusting.  

E-Print Network [OSTI]

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...

Thomas, F. L. (Frank Lincoln)

1929-01-01T23:59:59.000Z

204

Nano- and microscale particles and global electromagnetic resonances in the Earth-ionosphere cavity  

SciTech Connect (OSTI)

The influence of nano-and microscale particles (dust grains) on the global electromagnetic (Schumann) cavity has been studied in the context of two possible mechanisms. First, the presence of charged microscale particles in the ionospheric plasma modifies the dispersion properties of the upper boundary of the Schumann cavity and, thus, affects its eigenfrequencies and quality factor. Second, there is a relation between the dust concentration in the atmosphere and lightning discharges, which excite Schumann resonances. Therefore, dust grains can enhance the energy pumping of the cavity, thereby increasing the amplitude of electromagnetic oscillations in it.

Besedina, Yu. N.; Popel, S. I. [Russian Academy of Sciences, Institute of Geosphere Dynamics (Russian Federation)

2007-02-15T23:59:59.000Z

205

Thermo-Oxidation of Tokamak Carbon Dust  

SciTech Connect (OSTI)

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

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

2008-04-01T23:59:59.000Z

206

Quenching dust mixtures: A new microgravity testing method using electric particulate suspensions  

SciTech Connect (OSTI)

The electric particulate suspension (EPS) is a combustion ignition system under development at Iowa State University for the evaluation of quenching effects of powders in microgravity (quenching distance, ignition energy, and flammability limits). Both walls and (inert) particles can be tested as quenching media. The EPS method has potential as a benchmark design for quenching powder flames that would provide NASA and the scientific community with a new fire safety standard. Because of its simplicity and size, it is also suitable for tests on the International Space Station and the Mars Rover. The EPS method also supports combustion modeling by providing accurate measurement of flame-quenching distance as an important parameter in laminar flame theory because it is closely related to characteristic flame thickness and flame structure. In microgravity, the EPS method is expected to produce dust suspensions that are highly uniform (before ignition) compared to 1-g, where gravity can cause stratification of the suspension. Microgravity will also permit increased concentrations of particles to be tested (for a given electric field strength). Several EPS experiments are reviewed, including X-Y laser scans for cloud stratification, particle velocity distribution evaluation by the use of particle tracking velocimetry/particle image velocimetry and a leak hole sampling rig, and measurement of particle slip velocity by the use of laser Doppler anemometry. Sample quenching and ignition energy curves are presented for aluminum powder and coal dust. Only ground-based data at 1-g are reported.

Colver, G.M.; Greene, N.; Shoemaker, D.; Kim, S.W.; Yu, T.U. [Iowa State University, Ames, IA (US). Dept. of Mechanical Engineering

2004-10-15T23:59:59.000Z

207

Dustbuster: a compact impact-ionization time-of-flight mass spectrometer for in situ analysis of cosmic dust  

E-Print Network [OSTI]

a large target area with a reflectron, simultaneously optimizing mass resolution, particle detection. The resulting ions, with broad energy and angular distributions, are accelerated through a modified reflectron remote sensing, collection and analysis of dust grains that have survived impact on the Earth, capture

Stewart, Sarah T.

208

Observation of the spatial growth of self-excited dust-density waves T. M. Flanagan and J. Goree  

E-Print Network [OSTI]

Department of Physics and Astronomy, The University of Iowa, Iowa City, Iowa 52242, USA Received 12 October rate increases as gas pressure decreases. At a critical gas pressure, which is observed, a balance are comparatively much longer and easily observed. If a dust particle's Coulomb potential energy is larger than its

Goree, John

209

Void formation and dust cloud structure in (a)symmetric RF discharges  

SciTech Connect (OSTI)

The behaviour of dust particles in a discharge is the result of the concerted action of the charging process and forces like gravity, the ion and neutral drag force, and the thermophoretic force. Since the ion drag force plays a major role, the reactor geometry and the ion density profile are important parameters. In this paper we study the influence of the geometrical features of a radio-frequency discharge, such as asymmetry, ring electrodes, and a depression in the electrodes.

Goedheer, W.J.; Akdim, M.R.; Land, V. [FOM Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands)

2005-10-31T23:59:59.000Z

210

Nonlinear dust acoustic waves in inhomogeneous four-component dusty plasma with opposite charge polarity dust grains  

SciTech Connect (OSTI)

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.

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

211

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

SciTech Connect (OSTI)

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.

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

212

DUST IN A TYPE Ia SUPERNOVA PROGENITOR: SPITZER SPECTROSCOPY OF KEPLER'S SUPERNOVA REMNANT  

SciTech Connect (OSTI)

Characterization of the relatively poorly understood progenitor systems of Type Ia supernovae is of great importance in astrophysics, particularly given the important cosmological role that these supernovae play. Kepler's supernova remnant, the result of a Type Ia supernova, shows evidence for an interaction with a dense circumstellar medium (CSM), suggesting a single-degenerate progenitor system. We present 7.5-38 {mu}m infrared (IR) spectra of the remnant, obtained with the Spitzer Space Telescope, dominated by emission from warm dust. Broad spectral features at 10 and 18 {mu}m, consistent with various silicate particles, are seen throughout. These silicates were likely formed in the stellar outflow from the progenitor system during the asymptotic giant branch stage of evolution, and imply an oxygen-rich chemistry. In addition to silicate dust, a second component, possibly carbonaceous dust, is necessary to account for the short-wavelength Infrared Spectrograph and Infrared Array Camera data. This could imply a mixed chemistry in the atmosphere of the progenitor system. However, non-spherical metallic iron inclusions within silicate grains provide an alternative solution. Models of collisionally heated dust emission from fast shocks (>1000 km s{sup -1}) propagating into the CSM can reproduce the majority of the emission associated with non-radiative filaments, where dust temperatures are {approx}80-100 K, but fail to account for the highest temperatures detected, in excess of 150 K. We find that slower shocks (a few hundred km s{sup -1}) into moderate density material (n{sub 0} {approx} 50-250 cm{sup -3}) are the only viable source of heating for this hottest dust. We confirm the finding of an overall density gradient, with densities in the north being an order of magnitude greater than those in the south.

Williams, Brian J.; Borkowski, Kazimierz J.; Reynolds, Stephen P. [Physics Department, North Carolina State University, Raleigh, NC 27695-8202 (United States); Ghavamian, Parviz [Department of Physics, Astronomy, and Geosciences, Towson University, Towson, MD 21252 (United States); Blair, William P. [Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218-2686 (United States); Long, Knox S. [STScI, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Sankrit, Ravi, E-mail: brian.j.williams@nasa.gov [SOFIA/USRA, NASA Ames Research Center, M/S N211-3, Moffett Field, CA 94035 (United States)

2012-08-10T23:59:59.000Z

213

Extended silicate dust emission in PG QSOs  

E-Print Network [OSTI]

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.

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

214

Flammability limits of dusts: Minimum inerting concentrations  

SciTech Connect (OSTI)

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.

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

215

Structure and trapping of three-dimensional dust clouds in a capacitively coupled rf-discharge  

SciTech Connect (OSTI)

In this survey the recently found 'Coulomb balls' are discussed, which show an unusual kind of crystalline order. These three-dimensional dust clouds consisting of hundreds or thousands of micrometer-sized dust particles have a spherical shape and exist in a wide range of plasma conditions. Coulomb balls are optically highly transparent and have macroscopic dimensions of several millimeters in diameter. The clouds allow for the observation of each single particle and thus the complete reconstruction of the crystal structure by means of video microscopy techniques. The particles are arranged in distinct nested shells in which they form patterns with mostly five and six neighbors. The confinement of Coulomb balls by dielectric walls involves electric forces, surface charges, ion drag forces, and thermophoretic levitation. The thermophoretic force field is measured with tracer particles and particle image velocimetry (PIV). The electric forces are derived from simulations with the two-dimensional SIGLO-2D code. It is shown the the sum of all confining forces results in a stable potential well that describes levitation and spherical confinement of the Coulomb ball.

Arp, O.; Block, D.; Piel, A. [IEAP, Christian-Albrechts-University, D-24098 Kiel (Germany)

2005-10-31T23:59:59.000Z

216

Oblique interactions of dust density waves  

SciTech Connect (OSTI)

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.

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

217

Electric Dipole Radiation from Spinning Dust Grains  

E-Print Network [OSTI]

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.

B. T. Draine; A. Lazarian

1998-02-18T23:59:59.000Z

218

Cold condensation of dust in the ISM  

E-Print Network [OSTI]

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...

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

2015-01-01T23:59:59.000Z

219

Dispersion relations for the dust-acoustic wave under experimental conditions  

SciTech Connect (OSTI)

The dust acoustic wave dispersion relation is tested to quantify its sensitivity to many physical processes that are important in laboratory dusty plasmas. It is found that inverse Landau damping and ion-neutral collisions contribute about equally to the growth rate ?{sub i}, pointing to the advantage of using a kinetic model for the instability. The growth rate ?{sub i} increases the most with an increase of dust number density, followed by an increase in ion-drift speed. The quantities that cause ?{sub i} to decrease the most when they are increased are the dust-neutral collision rate followed by the ion-neutral collision rate, ion collection current onto dust particles, and the ion thermal speed. In general, ?{sub i} is affected more than ?{sub r} by the choice of processes that are included. Strong Coulomb-coupling effects can be included in a compressibility term. The susceptibilities derived here can be combined in various ways in a dispersion relation to account for different combinations of physical processes.

Suranga Ruhunusiri, W. D., E-mail: suranga-ruhunusiri@uiowa.edu; Goree, J. [Department of Physics and Astronomy, The University of Iowa, Iowa City, Iowa 52242 (United States)

2014-05-15T23:59:59.000Z

220

Molecular Hydrogen Emission from Protoplanetary Disks II. Effects of X-ray Irradiation and Dust Evolution  

E-Print Network [OSTI]

Detailed models for the density and temperature profiles of gas and dust in protoplanetary disks are constructed by taking into account X-ray and ultraviolet (UV) irradiation from a central T Tauri star, as well as dust size growth and settling toward the disk midplane. The spatial and size distributions of dust grains in the disks are numerically computed by solving the coagulation equation for settling dust particles. The level populations and line emission of molecular hydrogen are calculated using the derived physical structure of the disks. X-ray irradiation is the dominant heating source of the gas in the inner disk region and in the surface layer, while the far UV heating dominates otherwise. If the central star has strong X-ray and weak UV radiation, the H2 level populations are controlled by X-ray pumping, and the X-ray induced transition lines could be observable. If the UV irradiation is strong, the level populations are controlled by thermal collisions or UV pumping, depending on the properties of...

Nomura, H; Tsujimoto, M; Nakagawa, Y; Millar, T J

2007-01-01T23:59:59.000Z

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


221

Radial breathing mode of single-walled carbon nanotubes: Optical transition energies and chiral-index assignment  

E-Print Network [OSTI]

Radial breathing mode of single-walled carbon nanotubes: Optical transition energies and chiral of carbon nanotubes in aqueous suspen- sions by resonant Raman scattering of the radial breathing mode. We determine the energies of the first optical transition in metallic tubes and of the second optical

Nabben, Reinhard

222

A comparative analysis of 3D conformal deep inspiratory–breath hold and free-breathing intensity-modulated radiation therapy for left-sided breast cancer  

SciTech Connect (OSTI)

Patients undergoing radiation for left-sided breast cancer have increased rates of coronary artery disease. Free-breathing intensity-modulated radiation therapy (FB-IMRT) and 3-dimensional conformal deep inspiratory–breath hold (3D-DIBH) reduce cardiac irradiation. The purpose of this study is to compare the dose to organs at risk in FB-IMRT vs 3D-DIBH for patients with left-sided breast cancer. Ten patients with left-sided breast cancer had 2 computed tomography scans: free breathing and voluntary DIBH. Optimization of the IMRT plan was performed on the free-breathing scan using 6 noncoplanar tangential beams. The 3D-DIBH plan was optimized on the DIBH scan and used standard tangents. Mean volumes of the heart, the left anterior descending coronary artery (LAD), the total lung, and the right breast receiving 5% to 95% (5% increments) of the prescription dose were calculated. Mean volumes of the heart and the LAD were lower (p<0.05) in 3D-DIBH for volumes receiving 5% to 80% of the prescription dose for the heart and 5% for the LAD. Mean dose to the LAD and heart were lower in 3D-DIBH (p?0.01). Mean volumes of the total lung were lower in FB-IMRT for dose levels 20% to 75% (p<0.05), but mean dose was not different. Mean volumes of the right breast were not different for any dose; however, mean dose was lower for 3D-DIBH (p = 0.04). 3D-DIBH is an alternative approach to FB-IMRT that provides a clinically equivalent treatment for patients with left-sided breast cancer while sparing organs at risk with increased ease of implementation.

Reardon, Kelli A.; Read, Paul W.; Morris, Monica M. [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States); Reardon, Michael A. [Department of Radiology, University of Virginia, Charlottesville, VA (United States); Geesey, Constance [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States); Wijesooriya, Krishni, E-mail: kw5wx@hscmail.mcc.virginia.edu [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States)

2013-07-01T23:59:59.000Z

223

Algebraically general, gravito-electric rotating dust  

E-Print Network [OSTI]

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.

Lode Wylleman

2008-06-17T23:59:59.000Z

224

Design of a new cotton dust sampler  

E-Print Network [OSTI]

FIGURE Page Vertical elutriator cotton dust sampler The penetration curve of the VE which has a cutpoint of 9. 7 um and a slope of 1. 5 (Grimm, 1981) . . . . . . . 13 The penetration curve of the VE which has a cutpoint of 10. 5 um and a slope of l... of the cyclone cotton dust sampler 36 37 39 13 Cyclone sampler penetration curve which has a slope of 1. 31 and a cutpoint of 10. 1 um 45 14 Comparison of the penetration curves of the cyclone sampler and verticle elutriator 46 15 The relationship...

Hickman, Phillip Dean

2012-06-07T23:59:59.000Z

225

Characterization of human expired breath by solid phase microextraction and analysis using gas chromatography-mass spectrometry and differential mobility spectrometry  

E-Print Network [OSTI]

Breath analysis has potential to become a new medical diagnostic modality. In this thesis, a method for the analysis of human expired breath was developed using gas chromatography-mass spectroscopy. It was subsequently ...

Merrick, William (William F. W.)

2005-01-01T23:59:59.000Z

226

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...

227

airborne respirable dust: Topics by E-print Network  

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

Distributed Sensor Networks and Ad-hoc Networking 4 1.2.2 High Level Interpretation of Spatial Sensor Data 4 1.2.3 Distributed Processing 5 1.2.4 COTS Dust 6 2.0 COTS Dust...

228

Pseudopotentials of the particles interactions in complex plasmas  

SciTech Connect (OSTI)

This article discusses the effective interaction potentials in a complex dusty plasma. The interaction of electrons with atoms and the interaction between dusty particles are studied by the method of the dielectric response function. In the effective interaction, potential between electron and atom the quantum effects of diffraction were taken into account. On the curve of the interaction potential between dust particles under certain conditions the oscillations can be observed.

Ramazanov, T. S.; Moldabekov, Zh. A.; Dzhumagulova, K. N.; Muratov, M. M. [Al Farabi Kazakh National University, IETP, Tole bi 96a, Almaty 050012 (Kazakhstan)

2011-10-15T23:59:59.000Z

229

An Alternate Approach to Determine the Explosibility of Dusts  

E-Print Network [OSTI]

dust cloud; a 10,000 Joule (10 kJ) flame is subsequently forced through the dust cloud and the resulting pressure rise is measured. If the pressure rise exceeds one bar (14.5 psig), it is assumed that a deflagration occurred, and the dust is classified...

Ganesan, Balaji

2013-12-04T23:59:59.000Z

230

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

E-Print Network [OSTI]

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 ...

Xiang, Jingen

231

Study of metal dusting phenomenon and development of materials resistant to metal dusting.  

SciTech Connect (OSTI)

The deposition of carbon from carbonaceous gaseous environments is prevalent in many chemical and petrochemical processes such as reforming systems, syngas production systems, iron reduction plants, and others. One of the major consequences of carbon deposition is the degradation of structural materials by a phenomenon known as metal dusting. There are two major issues of importance in metal dusting. First is formation of carbon and subsequent deposition of carbon on metallic materials. Second is the initiation of metal dusting degradation of the alloy. Details are presented on a research program that is underway at Argonne National Laboratory to study the metal dusting phenomenon from a fundamental scientific base involving laboratory research in simulated process conditions and field testing of materials in actual process environments. The project has participation from the US chemical industry, alloy manufacturers, and the Materials Technology Institute, which serves the chemical process industry.

Natesan, K.

2002-03-13T23:59:59.000Z

232

Three-dimensional stability of dust-ion acoustic solitary waves in a magnetized multicomponent dusty plasma with negative ions  

SciTech Connect (OSTI)

Using the small-k expansion perturbation method, the three-dimensional stability of dust-ion acoustic solitary waves (DIASWs) in a magnetized multicomponent dusty plasma containing negative heavy ions and stationary variable-charge dust particles is analyzed. A nonlinear Zakharov-Kuznetsov equation adequate for describing these solitary structures is derived. Moreover, the basic features of the DIASWs are studied. The determination of the stability region leads to two different cases depending on the oblique propagation angle. In addition, the growth rate of the produced waves is estimated. The increase of either the negative ion number density or their temperatures or even the number density of the dust grains results in reducing the wave growth rate. Finally, the present results should elucidate the properties of DIASWs in a multicomponent plasma with negative ions, particularly in laboratory experiment and plasma process.

El-Taibany, W. F.; El-Shamy, E. F. [Department of Physics, Faculty of Science, Mansoura University, Damietta Branch, P.O. 34517, Damietta El-Gedida (Egypt); El-Bedwehy, N. A. [Department of Mathematics, Faculty of Science, Mansoura University, Damietta Branch, P.O. 34517, Damietta El-Gedida (Egypt)

2011-03-15T23:59:59.000Z

233

Recycling of electric-arc-furnace dust  

SciTech Connect (OSTI)

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.

Sresty, G.C.

1990-05-01T23:59:59.000Z

234

The general double-dust solution  

E-Print Network [OSTI]

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.

B. V. Ivanov

2003-02-04T23:59:59.000Z

235

"Study political science in a city that lives and breathes politics." carleton.ca/polisci  

E-Print Network [OSTI]

"Study political science in a city that lives and breathes politics." carleton.ca/polisci GRADUATE PROGRAMS IN SHAPE YOUR FUTURE BASED ON YOUR RESEARCH INTERESTS Where better to study political science than and PhD program in political science, as well as a collaborative specializa- tion in African Studies and

Dawson, Jeff W.

236

Breathing coherent phonons and caps fragmentation in carbon nanotubes following ultrafast laser pulses  

E-Print Network [OSTI]

driven by ultrafast laser pulses.1­3 The necessary conditions for generating such coherent phonons are i is larger than the duration of currently available ultrafast pulses. ii Measurements4­7 determinedBreathing coherent phonons and caps fragmentation in carbon nanotubes following ultrafast laser

Dumitrica,Traian

237

Thoracic CT-PET Registration Using a 3D Breathing Model  

E-Print Network [OSTI]

Thoracic CT-PET Registration Using a 3D Breathing Model Antonio Moreno1 , Sylvie Chambon1 , Anand P Orlando, USA Abstract. In the context of thoracic CT-PET volume registration, we present a novel method applications. We consider Computed Tomography (CT) and Positron Emission Tomography (PET) in thoracic regions

Paris-Sud XI, Université de

238

VentureBeat Smart meters could breathe life into flagging chip market  

E-Print Network [OSTI]

VentureBeat Smart meters could breathe life into flagging chip market April 1, 2009 | Camille Ricketts Even as the downturn dries up cleantech capital, smart-meter makers continue to do quite well, and major utilities like PG&E jumping on board, it looks like the smart-meter industry will hold strong

Lu, Chenyang

239

Computational mapping reveals dramatic effect of Hoogsteen breathing on duplex DNA reactivity  

E-Print Network [OSTI]

Computational mapping reveals dramatic effect of Hoogsteen breathing on duplex DNA reactivity Formaldehyde has long been recognized as a haz- ardous environmental agent highly reactive with DNA. Recently-ray and nuclear magnetic resonance techniques for observing weakly specific interactions of small organic

Vajda, Sandor

240

Intergalactic dust and its photoelectric heating  

E-Print Network [OSTI]

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.

Akio K. Inoue; Hideyuki Kamaya

2008-10-31T23:59:59.000Z

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


241

REVIEW OF PARTICLE PHYSICS  

E-Print Network [OSTI]

ONLINE PARTICLE PHYSICS INFORMATION 1.3. Particle Physics Information Platforms . . . . . . . . .14. Particle Physics Education and Outreach

Beringer, Juerg

2013-01-01T23:59:59.000Z

242

Review of Particle Physics  

E-Print Network [OSTI]

11. Particle Physics Education Sites . . . . . . . . .ONLINE PARTICLE PHYSICS INFORMATION 1.11. Particle Physics Education Sites . . . . . . . . . . 12.

Nakamura, Kenzo

2010-01-01T23:59:59.000Z

243

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

SciTech Connect (OSTI)

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

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

2012-12-15T23:59:59.000Z

244

ON THE EVOLUTION OF DUST MINERALOGY, FROM PROTOPLANETARY DISKS TO PLANETARY SYSTEMS  

SciTech Connect (OSTI)

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 interstellar medium 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 (composition, crystallinity, and grain size distribution) 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 mineralogy evolution with time for a total sample of 139 disks. The mean cluster age and disk fraction are used as indicators of the evolutionary stage of the different populations. Our results show that the disks in the different regions have similar distributions of mean grain sizes and crystallinity fractions ({approx}10%-20%) despite the spread in mean ages. Furthermore, there is no evidence of preferential grain sizes for any given disk geometry nor for the mean cluster crystallinity fraction to increase with mean age in the 1-8 Myr range. The main implication is that a modest level of crystallinity is established in the disk surface early on ({<=}1 Myr), reaching an equilibrium that is independent of what may be happening in the disk midplane. These results are discussed in the context of planet formation, in comparison with mineralogical results from small bodies in our own solar system.

Oliveira, Isa; Van Dishoeck, Ewine F. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Olofsson, Johan [Max-Planck Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg (Germany); Pontoppidan, Klaus M. [California Institute of Technology, Division for Geological and Planetary Sciences, MS 150-21, Pasadena, CA 91125 (United States); Augereau, Jean-Charles [UJF-Grenoble 1/CNRS-INSU, Institut de Planetologie et d'Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, F-38041 (France); MerIn, Bruno, E-mail: oliveira@strw.leidenuniv.nl [Herschel Science Center, European Space Agency (ESA), P.O. Box 78, 28691 Villanueva de la Canada (Madrid) (Spain)

2011-06-10T23:59:59.000Z

245

Analysis of dust samples collected from spent nuclear fuel interim storage containers at Hope Creek, Delaware, and Diablo Canyon, California.  

SciTech Connect (OSTI)

Potentially corrosive environments may form on the surface of spent nuclear fuel dry storage canisters by deliquescence of deposited dusts. To assess this, samples of dust were collected from in-service dry storage canisters at two near-marine sites, the Hope Creek and Diablo Canyon storage installations, and have been characterized with respect to mineralogy, chemistry, and texture. At both sites, terrestrially-derived silicate minerals, including quartz, feldspars, micas, and clays, comprise the largest fraction of the dust. Also significant at both sites were particles of iron and iron-chromium metal and oxides generated by the manufacturing process. Soluble salt phases were minor component of the Hope Creek dusts, and were compositionally similar to inland salt aerosols, rich in calcium, sulfate, and nitrate. At Diablo Canyon, however, sea-salt aerosols, occurring as aggregates of NaCl and Mg-sulfate, were a major component of the dust samples. The seasalt aerosols commonly occurred as hollow spheres, which may have formed by evaporation of suspended aerosol seawater droplets, possibly while rising through the heated annulus between the canister and the overpack. The differences in salt composition and abundance for the two sites are attributed to differences in proximity to the open ocean and wave action. The Diablo Canyon facility is on the shores of the Pacific Ocean, while the Hope Creek facility is on the shores of the Delaware River, several miles from the open ocean.

Bryan, Charles R.; Enos, David George

2014-07-01T23:59:59.000Z

246

Evaluating chemical and physical properties of grain dust for use in an explosion hazard indicator  

E-Print Network [OSTI]

. 06 iIm 15. 0 0 ) 15. 6 10. 0 5. 0 3 4 7. 2 8. 5 5 6 4 0 . . . 3. 3 1. 7 1. 7 14 1 ~ 5 12 3. 0 0. 0 O CV O Yl CO O CO O N I I I O O ICI I CI O CC I CI cn 4 0 CV ch I CO I O O CO I O I O C: CI I Particle Size Ranges... 3 Q 2. 1 0. 6 0. 6 I CI CI 6 IO Yl CD 0 CI P4 I I I I I I CI N N 0 Yl (O I CI C) I U3 CI co I I CI CI CI I m Particle Size Ranges, um FIG. 14 Coulter Counter particle size distribution of rice dust, 30. 0 25. 0 20. 0 Mean...

Plemons, Dorothy Sue

1981-01-01T23:59:59.000Z

247

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

SciTech Connect (OSTI)

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

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

248

Properties of comet 9P/Tempel 1 dust immediately following excavation by Deep Impact  

E-Print Network [OSTI]

We analyzed Deep Impact High Resolution Instrument (HRI) images acquired within the first seconds after collision of the Deep Impact impactor with the nucleus of comet 9P/Tempel 1. These images reveal an optically thick ejecta plume that casts a shadow on the surface of the nucleus. Using the 3D radiative transfer code HYPERION we simulated light scattering by the ejecta plume, taking into account multiple scattering of light from the ejecta, the surrounding nuclear surface and the actual observational geometry (including an updated plume orientation geometry that accounts for the latest 9P/Tempel 1 shape model). Our primary dust model parameters were the number density of particles, their size distribution and composition. We defined the composition through the density of an individual particle and the ratio of its material constituents, which we considered to be refractories, ice and voids. The results of our modeling indicate a dust/ice mass ratio for the ejecta particles of at least 1. To further constrai...

Nagdimunov, Lev; Wolff, Michael; A'Hearn, Michael F; Farnham, Tony L

2014-01-01T23:59:59.000Z

249

Differences in pulmonary responses of rats, other animals, and humans to chronic inhalation of silica and other particles  

SciTech Connect (OSTI)

The pulmonary carcinogenicity of quartz in rats supports the plausibility of silica-induced lung cancer in humans. However, pulmonary responses of rats to dusts differ from those of other rodents, and may differ from those of humans. Dust-exposed rats have a greater propensity than mice or hamsters for epithelial hyperplasia, metaplasia, and fibrosis. Lung tumors occur in rats, but not mice or hamsters, treated with quartz, or exposed chronically to several other dusts. There are few opportunities for directly comparing the susceptibilities of rats and humans to dust-induced lung tumors. Because of the uncertain human responses to silica and many other particles, the negative human lung cancer response to coal dust may provide the best opportunity to calibrate responses of rats against those of humans. Historical dust lung burdens in coal miners were in the range of those associated with carcinogenicity in rats exposed to several dusts, but the carcinogenicity of coal dust in rats is unknown. The usefulness of tumor data from rats for predicting human lung cancer risk from inhaled silica and other dusts remains uncertain.

Mauderly, J.L.

1993-12-31T23:59:59.000Z

250

Breath gating of cardiac PET using 13N-NH3: An optimization  

E-Print Network [OSTI]

was carried out using 13 N-NH3 on two dierent PET/CT scanners: a Siemens Biograph 64 and a Siemens mCT PET. In this project the breath-motion was estimated using an ane transformation on the obtained images, from which- jekt er udført ved brug af 13 N-NH3 på to skannere, henholdsvis en Siemens Biograph 64 og en Siemens m

251

Numerical models analysis of energy conversion process in air-breathing laser propulsion  

SciTech Connect (OSTI)

Energy source was considered as a key essential in this paper to describe energy conversion process in air-breathing laser propulsion. Some secondary factors were ignored when three independent modules, ray transmission module, energy source term module and fluid dynamic module, were established by simultaneous laser radiation transportation equation and fluid mechanics equation. The incidence laser beam was simulated based on ray tracing method. The calculated results were in good agreement with those of theoretical analysis and experiments.

Hong Yanji; Song Junling; Cui Cunyan; Li Qian [Academy of Equipment Command and Technology, 101416 Beijing (China)

2011-11-10T23:59:59.000Z

252

Three-dimensional computer modeling of particulate flow around dust monitors  

SciTech Connect (OSTI)

SOLA-DM is a three-dimensional finite-difference computer code designed to model the dynamics of an incompressible fluid and the transport of discrete particulate material around obstacles impervious to flow. The numerical methods used in this code are described. SOLA-DM was used to predict the particle flux sampled by the 10-mm Dorr-Oliver Cyclone and MINIRAM dust monitors. Various geometric and dynamic variations of monitor and airflow combinations were tested. The code predictions are shown in computer-generated graphic plots.

Nichols, B.D.; Gregory, W.S.

1987-01-01T23:59:59.000Z

253

The effect of dust size distribution on quantum dust acoustic wave  

SciTech Connect (OSTI)

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.

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

254

Technology Assessment of Dust Suppression Techniques Applied During Structural Demolition  

SciTech Connect (OSTI)

Hanford, Fernald, Savannah River, and other sites are currently reviewing technologies that can be implemented to demolish buildings in a cost-effective manner. In order to demolish a structure properly and, at the same time, minimize the amount of dust generated from a given technology, an evaluation must be conducted to choose the most appropriate dust suppression technology given site-specific conditions. Thus, the purpose of this research, which was carried out at the Hemispheric Center for Environmental Technology (HCET) at Florida International University, was to conduct an experimental study of dust aerosol abatement (dust suppression) methods as applied to nuclear D and D. This experimental study targeted the problem of dust suppression during the demolition of nuclear facilities. The resulting data were employed to assist in the development of mathematical correlations that can be applied to predict dust generation during structural demolition.

Boudreaux, J.F.; Ebadian, M.A.; Williams, P.T.; Dua, S.K.

1998-10-20T23:59:59.000Z

255

Old supernova dust factory revealed at the Galactic center  

E-Print Network [OSTI]

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.

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

2015-01-01T23:59:59.000Z

256

Dust accelerators and their applications in high-temperature plasmas  

SciTech Connect (OSTI)

The perennial presence of dust in high-temperature plasma and fusion devices has been firmly established. Dust inventory must be controlled, in particular in the next-generation steady-state fusion machines like ITER, as it can pose significant safety hazards and potentially interfere with fusion energy production. Much effort has been devoted to gening rid of the dust nuisance. We have recognized a number of dust-accelerators applications in magnetic fusion, including in plasma diagnostics, in studying dust-plasma interactions, and more recently in edge localized mode (ELM)'s pacing. With the applications in mind, we will compare various acceleration methods, including electrostatic, gas-drag, and plasma-drag acceleration. We will also describe laboratory experiments and results on dust acceleration.

Wang, Zhehui [Los Alamos National Laboratory; Ticos, Catakin M [NILPRP, ROMANIA

2010-01-01T23:59:59.000Z

257

Alveolar breath sampling and analysis to assess exposures to methyl tertiary butyl ether (MTBE) during motor vehicle refueling  

SciTech Connect (OSTI)

In this study we present a sampling and analytical methodology that can be used to assess consumers` exposures to methyl tertiary butyl ether (MTBE) that may result from routine vehicle refueling operations. The method is based on the collection of alveolar breath samples using evacuated one-liter stainless steel canisters and analysis using a gas chromatograph-mass spectrometer equipped with a patented `valveless` cryogenic preconcentrator. To demonstrate the utility of this approach, a series of breath samples was collected from two individuals (the person pumping the fuel and a nearby observer) immediately before and for 64 min after a vehicle was refueled with premium grade gasoline. Results demonstrate low levels of MTBE in both subjects` breaths before refueling, and levels that increased by a factor of 35 to 100 after the exposure. Breath elimination models fitted to the post exposure measurements indicate that the half-life of MTBE in the first physiological compartment was between 1.3 and 2.9 min. Analysis of the resulting models suggests that breath elimination of MTBE during the 64 min monitoring period was approximately 155 {mu}g for the refueling subject while it was only 30 {mu}g for the nearby observer. This analysis also shows that the post exposure breath elimination of other gasoline constituents was consistent with previously published observations. 20 refs., 3 figs., 4 tabs.

Lindstrom, A.B.; Pleil, J.D. [U.S. Environmental Protection Agency, Research Triangle Park, NC (United States)

1996-07-01T23:59:59.000Z

258

Zinc recovery by ultrasound acid leaching of double kiln treated electric arc furnace dust  

SciTech Connect (OSTI)

The need to convert 70,000 tons a year of electric arc furnace (EAF) dust into an environmentally safe or recyclable product has encouraged studies to reclaim zinc from this waste material. Successful characterization of a double-kiln calcine, produced from EAF dust, has shown that the calcine pellets consisted mainly of zinc oxide plates with some iron oxide particles. Preliminary leaching tests using hydrochloric and sulfuric acids indicated that this calcine is suitable for selective ultrasound leaching of zinc. A factorially designed screening test using hydrochloric acid showed that ultrasound significantly lowered iron dissolution and increased zinc dissolution, thus enhancing the selective leaching of zinc. Ultrasound, temperature, air bubbling rate and acidity increased the sulfuric acid selectivity, while fluorosilicic acid was not selective. Reactor characterization through ultrasonic field measurements led to the selection of reactor and ultrasound bath, which were utilized to enhance the selectivity of a laboratory scale sulfuric acid leaching of a double-kiln treated electric arc furnace dust. Results indicated that ultrasonic leaching of this calcine is a satisfactory technique to selectively separate zinc from iron. After further iron removal by precipitation and cementation of nickel, it was possible to electrowin zinc from the leach liquor under common industrial conditions, with current efficiencies from 86% through 92% being observed. Calcine washing showed that a substantial chloride removal is possible, but fluoride ion in the electrolyte caused deposit sticking during electrowinning.

Barrera Godinez, J.A.

1989-01-01T23:59:59.000Z

259

Dust acoustic shock waves in two temperatures charged dusty grains  

SciTech Connect (OSTI)

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

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

2011-11-15T23:59:59.000Z

260

Modeling dust as component minerals in the Community Atmosphere Model: development of framework and impact on radiative forcing  

SciTech Connect (OSTI)

The mineralogy of desert dust is important due to its effect on radiation, clouds and biogeochemical cycling of trace nutrients. This study presents the simulation of dust radiative forcing as a function of both mineral composition and size at the global scale using mineral soil maps for estimating emissions. Externally mixed mineral aerosols in the bulk aerosol module in the Community Atmosphere Model version 4 (CAM4) and internally mixed mineral aerosols in the modal aerosol module in the Community Atmosphere Model version 5.1 (CAM5) embedded in the Community Earth System Model version 1.0.5 (CESM) are speciated into common mineral components in place of total dust. The simulations with mineralogy are compared to available observations of mineral atmospheric distribution and deposition along with observations of clear-sky radiative forcing efficiency. Based on these simulations, we estimate the all-sky direct radiative forcing at the top of the atmosphere as +0.05Wm?2 for both CAM4 and CAM5 simulations with mineralogy and compare this both with simulations of dust in release versions of CAM4 and CAM5 (+0.08 and +0.17Wm?2) and of dust with optimized optical properties, wet scavenging and particle size distribution in CAM4 and CAM5, ?0.05 and ?0.17Wm?2, respectively. The ability to correctly include the mineralogy of dust in climate models is hindered by its spatial and temporal variability as well as insufficient global in-situ observations, incomplete and uncertain source mineralogies and the uncertainties associated with data retrieved from remote sensing methods.

Scanza, Rachel; Mahowald, N.; Ghan, Steven J.; Zender, C. S.; Kok, J. F.; Liu, Xiaohong; Zhang, Y.; Albani, Samuel

2015-01-01T23:59:59.000Z

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


261

Aerosol Impacts on California Winter Clouds and Precipitation during CalWater 2011: Local Pollution versus Long-Range Transported Dust  

SciTech Connect (OSTI)

Mineral dust aerosols often observed over California in winter and spring, associated with long-range transport from Asia and Sahara, have been linked to enhanced precipitation based on observations. Local anthropogenic pollution, on the other hand, was shown in previous observational and modeling studies to reduce precipitation. Here we incorporate recent developments in ice nucleation parameterizations to link aerosols with ice crystal formation in a spectral-bin cloud microphysical model coupled with the Weather Research and Forecasting (WRF) model, to examine the relative and combined impacts of dust and local pollution particles on cloud properties and precipitation type and intensity. Simulations are carried out for two cloud cases with contrasting meteorology and cloud dynamics that occurred on February 16 (FEB16) and March 02 (MAR02) from the CalWater 2011 field campaign. In both cases, observations show the presence of dust and biological particles in a relative pristine environment. The simulated cloud microphysical properties and precipitation show reasonable agreement with aircraft and surface measurements. Model sensitivity experiments indicate that in the pristine environment, the dust and biological aerosol layers increase the accumulated precipitation by 10-20% from the Central Valley to the Sierra Nevada Mountains for both FEB16 and MAR02 due to a ~40% increase in snow formation, validating the observational hypothesis. Model results show that local pollution increases precipitation over the windward slope of the mountains by few percent due to increased snow formation when dust is present but reduces precipitation by 5-8% if dust is removed on FEB16. The effects of local pollution on cloud microphysics and precipitation strongly depend on meteorology including the strength of the Sierra Barrier Jet, and cloud dynamics. This study further underscores the importance of the interactions between local pollution, dust, and environmental conditions for assessing aerosol effects on cold season precipitation in California.

Fan, Jiwen; Leung, Lai-Yung R.; DeMott, Paul J.; Comstock, Jennifer M.; Singh, Balwinder; Rosenfeld, Daniel; Tomlinson, Jason M.; White, Allen B.; Prather, Kimberly; Minnis, Patrick; Ayers, J. K.; Min, Qilong

2014-01-03T23:59:59.000Z

262

Space Dust Analysis Could Provide Clues to Solar System Origins  

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

of oxygen. Isotope analysis could help confirm that the dust originated outside the solar system, but it's a process that would destroy the precious samples. For now,...

263

The Differential Lifetimes of Protostellar Gas and Dust Disks  

E-Print Network [OSTI]

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.

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

2005-03-22T23:59:59.000Z

264

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...

265

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...

266

ISM dust feedback from low to high mass stars  

E-Print Network [OSTI]

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.

Falceta-Goncalves; D.

2007-10-26T23:59:59.000Z

267

Soil water and particle size distribution influence laboratory-generated PM10 Nicholaus M. Madden a,*, Randal J. Southard a  

E-Print Network [OSTI]

on gravimetric soil water content (GWC) and soil texture. A mechanical laboratory dust generator was used to testSoil water and particle size distribution influence laboratory-generated PM10 Nicholaus M. Madden a Soil particle size distribution Soil water content a b s t r a c t Management of soils to reduce

Ahmad, Sajjad

268

Dust and Molecules at High Redshift  

E-Print Network [OSTI]

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.

F. Combes

1998-12-23T23:59:59.000Z

269

PROBING INTERSTELLAR DUST WITH INFRARED ECHOES FROM THE Cas A SUPERNOVA  

SciTech Connect (OSTI)

We present the analysis of an Infrared Spectrograph 5-38 {mu}m spectrum and Multiband Imaging Photometer for Spitzer photometric measurements of an infrared echo near the Cassiopeia A (Cas A) supernova (SN) remnant observed with the Spitzer Space Telescope. We have modeled the recorded echo accounting for polycyclic aromatic hydrocarbons (PAHs), quantum-heated carbon and silicate grains, as well as thermal carbon and silicate particles. Using the fact that optical light-echo spectroscopy has established that Cas A originated from a Type IIb SN explosion showing an optical spectrum remarkably similar to the prototypical Type IIb SN 1993J, we use the latter to construct template data input for our simulations. We are then able to reproduce the recorded infrared echo spectrum by combining the emission of dust heated by the UV burst produced at the shock breakout after the core-collapse and dust heated by optical light emitted near the visual maximum of the SN light curve, where the UV burst and optical light curve characteristics are based on SN 1993J. We find a mean density of {approx}680 H cm{sup -3} for the echo region, with a size of a few light years across. We also find evidence of dust processing in the form of a lack of small PAHs with less than {approx}300 carbon atoms, consistent with a scenario of PAHs destruction by the UV burst via photodissociation at the estimated distance of the echo region from Cas A. Furthermore, our simulations suggest that the weak 11 {mu}m features of our recorded infrared echo spectrum are consistent with a strong dehydrogenated state of the PAHs. This exploratory study highlights the potential of investigating dust processing in the interstellar medium through infrared echoes.

Vogt, Frederic P. A. [Mount Stromlo Observatory, Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Besel, Marc-Andre; Krause, Oliver; Dullemond, Cornelis P., E-mail: fvogt@mso.anu.edu.au [Max-Planck Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg (Germany)

2012-05-10T23:59:59.000Z

270

Particle Astrophysics  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 - September 2006 TheSteven Ashby Dr.presentationsParticipant ObligationsParticle

271

The application of reflected light microscopy, scanning electron microscopy-energy dispersive spectroscopy, Auger electron spectroscopy and electron microprobe analysis to the study of dusts  

SciTech Connect (OSTI)

Over 500,000 tons of electric arc furnace (EAF) dust is generated each year in the US. The mineralogy and characterization of this dust is being studied to determine the phases and relationships of the valuable zinc, the hazardous lead, cadmium, and chromium, and the deleterious chlorine and fluorine. EAF dust averages 15--20% zinc and is therefore a potential source for 100,000 tons of zinc per year. The major mineralogical phases of EAF dust are franklinite (ZnFe[sub 2]O[sub 4]), magnetite (FeFe[sub 2]O[sub 4]), jacobsite (MnFe[sub 2]O[sub 4]), solid solutions between franklinite-magnetite-jacobsite, and zincite (ZnO). Franklinite, magnetite, and jacobsite solid solutions commonly are cruciform or dendritic crystals in a Ca-Fe-Si matrix and contain up to 5% chromium. Magnetite also occurs as spheres partially oxidized to hematite (Fe[sub 2]O[sub 3]) along its octahedral planes. The dust particles are predominantly in the form of spheres and broken spheres, ranging in size from 200 [mu]m to less than 1 [mu]m. Although many spheres are in the size ranges of 40--50 [mu]m and 10--20 [mu]m, most are less than 1 [mu]m in diameter. Automated scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) probed 118 particles in search of chlorine phases. Chlorine-bearing lime (CaO) was identified by that SEM study. In addition, chlorine is present as hydrophylite (CaCl[sub 2]) and sylvite (KCl). Auger electron spectroscopy (AES) was used to sputter the outer 180[angstrom] layer of the dust particles to search for the possible presence of cotunnite (PbCl[sub 2]) coatings, but none were detected. Minor phases detected include chalcopyrite (CuFeS[sub 2]), sphalerite (ZnS), pyrite (FeS[sub 2]), and coke.

Hagni, A.M.; Hagni, R.D. (Univ. of Missouri, Rolla, MO (United States). Dept. of Geology and Geophysics)

1993-03-01T23:59:59.000Z

272

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

E-Print Network [OSTI]

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

Highwood, Ellie

273

Direct Characterization of Airborne Particles Associated with Arsenic-rich Mine Tailings: Particle Size Mineralogy and Texture  

SciTech Connect (OSTI)

Windblown and vehicle-raised dust from unvegetated mine tailings can be a human health risk. Airborne particles from As-rich abandoned Au mine tailings from Nova Scotia, Canada have been characterized in terms of particle size, As concentration, As oxidation state, mineral species and texture. Samples were collected in seven aerodynamically fractionated size ranges (0.5-16 {micro}m) using a cascade impactor deployed at three tailings fields. All three sites are used for recreational activities and off-road vehicles were racing on the tailings at two mines during sample collection. Total concentrations of As in the <8 {micro}m fraction varied from 65 to 1040 ng/m{sup 3} of air as measured by proton-induced X-ray emission (PIXE) analysis. The same samples were analysed by synchrotron-based microfocused X-ray absorption near-edge spectroscopy ({micro}XANES) and X-ray diffraction ({micro}XRD) and found to contain multiple As-bearing mineral species, including Fe-As weathering products. The As species present in the dust were similar to those observed in the near-surface tailings. The action of vehicles on the tailings surface may disaggregate material cemented with Fe arsenate and contribute additional fine-grained As-rich particles to airborne dust. Results from this study can be used to help assess the potential human health risks associated with exposure to airborne particles from mine tailings.

M Corriveau; H Jamieson; M Parsons; J Campbell; A Lanzirotti

2011-12-31T23:59:59.000Z

274

Paramagnetic alignment of thermally rotating dust  

E-Print Network [OSTI]

Paramagnetic alignment of thermally rotating oblate dust grains is studied analytically for finite ratios of grain to gas temperatures. For such ratios, the alignment of angular momentum J in respect to the grain axis of maximal inertia is only partial. We treat the alignment of J using perturbative methods and disentangle the problem of J alignment in grain body axes from that of J alignment in respect to magnetic field. This enables us to find the alignment of grain axes to magnetic field and thus relate our theory to polarimetric observations.Our present results are applicable to the alignment of both paramagnetic and superparamagnetic grains.

A. Lazarian

1997-02-16T23:59:59.000Z

275

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc Documentation RUC : XDCResearchWarmingMethaneProductsCSSEFProductsMerged andAerosol OpticalDust

276

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed Newcatalyst phases onOrganizationElectronic Reading2Q)382 THE HUMANlviA,'{ '297 Dust.

277

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

SciTech Connect (OSTI)

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.

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

278

AN EXTRACTION AND CURATION TECHNIQUE FOR PARTICLES CAPTURED IN AEROGEL COLLECTORS. A.  

E-Print Network [OSTI]

cometary, interplanetary and interstellar dust captured in aerogel collectors. The curation strategy (or strategies) for STAR-DUST remain to be defined. Here we present a technique for curation of particles captured in aerogel which will simultaneously preserve the entire particle track, and could allow for the elemental in situ analysis of both the particle residue at the terminus of the track and any particle residues located along the track. This builds on work that we have previously reported elsewhere[1]. developed a technique for extracting aerogel wedge-shaped “keystones ” that satisfy this requirement. In Fig. 1 we show top and side views of such an extracted wedge, containing a captured particle (Fig. 2) and its track. In Fig. 3, we show the excavated “pit”, demonstrating that there is essentially no disturbance beyond the extraction region. Even very long

unknown authors

279

The large scale dust lanes of the Galactic bar  

E-Print Network [OSTI]

(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.

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

2007-11-15T23:59:59.000Z

280

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

E-Print Network [OSTI]

, 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...

Pargmann, Amber Rae

2001-01-01T23:59:59.000Z

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


281

The application scope of the reductive perturbation method and the upper limit of the dust acoustic solitary waves in a dusty plasma  

SciTech Connect (OSTI)

The dust acoustic solitary waves have been numerically investigated by using one dimensional electrostatic particle-in-cell method. By comparing the numerical results with those obtained from the traditional reductive perturbation method, it is found that there exist the maximum dimensionless amplitude and propagation speed of the dust acoustic solitary wave. And these limitations of the solitary wave are explained by using the Sagdeev potential technique. Furthermore, it is noticed that although ? ? 1 is required in the reductive perturbation method generally, the reductive perturbation method is also valid for ??

Qi, Xin; Xu, Yan-xia; Duan, Wen-shan, E-mail: duanws@nwnu.edu.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China and Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou, 730070 Gansu (China)] [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China and Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou, 730070 Gansu (China); Yang, Lei, E-mail: lyang@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China and Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou, 730070 Gansu (China) [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China and Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou, 730070 Gansu (China); Department of Physics, Lanzhou University, Lanzhou 730000 (China)

2014-01-15T23:59:59.000Z

282

A real-time respiration position based passive breath gating equipment for gated radiotherapy: A preclinical evaluation  

SciTech Connect (OSTI)

Purpose: To develop a passive gating system incorporating with the real-time position management (RPM) system for the gated radiotherapy. Methods: Passive breath gating (PBG) equipment, which consists of a breath-hold valve, a controller mechanism, a mouthpiece kit, and a supporting frame, was designed. A commercial real-time positioning management system was implemented to synchronize the target motion and radiation delivery on a linear accelerator with the patient's breathing cycle. The respiratory related target motion was investigated by using the RPM system for correlating the external markers with the internal target motion while using PBG for passively blocking patient's breathing. Six patients were enrolled in the preclinical feasibility and efficiency study of the PBG system. Results: PBG equipment was designed and fabricated. The PBG can be manually triggered or released to block or unblock patient's breathing. A clinical workflow was outlined to integrate the PBG with the RPM system. After implementing the RPM based PBG system, the breath-hold period can be prolonged to 15-25 s and the treatment delivery efficiency for each field can be improved by 200%-400%. The results from the six patients showed that the diaphragm motion caused by respiration was reduced to less than 3 mm and the position of the diaphragm was reproducible for difference gating periods. Conclusions: A RPM based PBG system was developed and implemented. With the new gating system, the patient's breath-hold time can be extended and a significant improvement in the treatment delivery efficiency can also be achieved.

Hu Weigang; Xu Anjie; Li Guichao; Zhang Zhen; Housley, Dave; Ye Jinsong [Department of Radiation Oncology, Fudan University Shanghai Cancer Center and Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Department of Radiation Oncology, Swedish Cancer Institute, Seattle, Washington 98104 (United States)

2012-03-15T23:59:59.000Z

283

ANALYSIS OF DUST DELIQUESCENCE FOR FEP SCREENING  

SciTech Connect (OSTI)

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.

C. Bryan

2005-08-26T23:59:59.000Z

284

Constraining oceanic dust deposition using surface ocean dissolved Al  

E-Print Network [OSTI]

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

Zender, Charles

285

Dynamics of Finite Dust Clouds in a Magnetized Anodic Plasma  

SciTech Connect (OSTI)

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.

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

286

E-Print Network 3.0 - atmospheric dust dispersion Sample Search...  

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

of regional dust modelling to the wind speed and the emissions schemes: Impact on the hourly dust previsibility Summary: - Atmospheres , under revision Menut L., 2008,...

287

E-Print Network 3.0 - airborne house dust Sample Search Results  

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

of regional dust modelling to the wind speed and the emissions schemes: Impact... on the hourly dust previsibility Laurent MENUT (1), Cyril MOULIN (2), Isabelle CHIAPELLO (3)...

288

E-Print Network 3.0 - aluminum dust explosion Sample Search Results  

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

retention Explosion with air 100 Tungsten Activation 100-400 Dust... of traditional plasma diagnostics. Who has resources, time to tackle it ? 12;Dust diagnostics in ITER ?...

289

E-Print Network 3.0 - abrasive dusts avaliacao Sample Search...  

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

field observations indicate that dust production occurs via self-abrasion... , dust production reportedly occurred by a "self-abrasion" process of saltating diatomite flakes,...

290

Processing electric arc furnace dust into saleable chemical products  

SciTech Connect (OSTI)

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.

NONE

1998-04-01T23:59:59.000Z

291

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

SciTech Connect (OSTI)

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

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

2009-01-01T23:59:59.000Z

292

Existence domains of dust-acoustic solitons and supersolitons  

SciTech Connect (OSTI)

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.

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

293

Sheath formation under collisional conditions in presence of dust  

SciTech Connect (OSTI)

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.

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

294

Control of metal dusting corrosion in Ni-base alloys.  

SciTech Connect (OSTI)

Metal dusting is a major issue in plants used in the production of hydrogen-and methanol-reformer systems, and syngas (H{sub 2}/CO mixtures) systems that are pertinent to the chemical and petrochemical industries. Usually, metal dusting corrosion has two stages: incubation and growth resulting in propagation of metal dusting pits. The two stages were studied by scanning electron microscopy and profile mapping to evaluate the scale of the surface oxide in the initiation and propagation of metal dusting attack. The initiation occurs because of the presence of defects, and the propagation is determined by the diffusion of carbon into the alloy. The carbon diffusion pathways can be blocked by periodically oxidizing alloy surface at moderate temperatures in controlled atmospheres. It was concluded that metal dusting degradation can be mitigated by selecting an alloy with a long incubation time and subjecting it to intermediate oxidation.

Zeng, Z.; Natesan, K.; Energy Technology

2007-11-01T23:59:59.000Z

295

Differentiation between smokers and non-smokers by breath sound analysis  

E-Print Network [OSTI]

-smokers. While classification accuracy for the inspiration data is less than 60%, over 70% accuracy is achieved using the expiration data. The accuracy is improved to 80% for inspiration data and 76. 7% for expiration data when the mean parameters of 5 breaths... using the program GRFIL7. 12 4 Power spectrum for a typical expiration using a 10% cosine taper window function and a 512 point FFT 15 5 Parameters generated for a typical expiration 6 Plot of average expiration spectra for all subjects 7 Plot...

Mesibov, Steven

1987-01-01T23:59:59.000Z

296

Fine Structure of the Radial Breathing Mode in Double-Wall Carbon Nanotubes  

E-Print Network [OSTI]

The analysis of the Raman scattering cross section of the radial breathing modes of double-wall carbon nanotubes allowed to determine the optical transitions of the inner tubes. The Raman lines are found to cluster into species with similar resonance behavior. The lowest components of the clusters correspond well to SDS wrapped HiPco tubes. Each cluster represents one particular inner tube inside different outer tubes and each member of the clusters represents one well defined pair of inner and outer tubes. The number of components in one cluster increases with decreasing of the inner tube diameter and can be as high as 14.

R. Pfeiffer; F. Simon; H. Kuzmany; V. N. Popov

2005-08-09T23:59:59.000Z

297

Ordered dust structures in a glow discharge  

SciTech Connect (OSTI)

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.

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

298

A new method to generate dust with astrophysical properties  

SciTech Connect (OSTI)

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

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

2010-04-21T23:59:59.000Z

299

Controlling Silver Dust and Fumes at Mine Refinery  

E-Print Network [OSTI]

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

R. A. Haney; M. P. Valoski

300

Theoretical study of head-on collision of dust acoustic solitary waves in a strongly coupled complex plasma  

SciTech Connect (OSTI)

We investigate the propagation characteristics of two counter propagating dust acoustic solitary waves (DASWs) undergoing a head-on collision, in the presence of strong coupling between micron sized charged dust particles in a complex plasma. A coupled set of nonlinear dynamical equations describing the evolution of the two DASWs using the extended Poincaré-Lighthill-Kuo perturbation technique is derived. The nature and extent of post collision phase-shifts of these solitary waves are studied over a wide range of dusty plasma parameters in a strongly and a weakly coupled medium. We find a significant change in the nature and amount of phase delay in the strongly coupled regime as compared to a weakly coupled regime. The phase shift is seen to change its sign beyond a threshold value of compressibility of the medium for a given set of dusty plasma parameters.

Jaiswal, S., E-mail: surabhi@ipr.res.in; Bandyopadhyay, P.; Sen, A. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

2014-05-15T23:59:59.000Z

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


301

Inertia driven radial breathing and nonlinear relaxation in cylindrically confined pure electron plasma  

SciTech Connect (OSTI)

The dynamics of cylindrically trapped electron plasma has been investigated using a newly developed 2D Electrostatic PIC code that uses unapproximated, mass-included equations of motion for simulation. Exhaustive simulations, covering the entire range of Brillouin ratio, were performed for uniformly filled circular profiles in rigid rotor equilibrium. The same profiles were then loaded away from equilibrium with an initial value of rigid rotation frequency different from that required for radial force balance. Both these sets of simulations were performed for an initial zero-temperature or cold load of the plasma with no spread in either angular velocity or radial velocity. The evolution of the off-equilibrium initial conditions to a steady state involve radial breathing of the profile that scales in amplitude and algebraic growth with Brillouin fraction. For higher Brillouin fractions, the growth of the breathing mode is followed by complex dynamics of spontaneous hollow density structures, excitation of poloidal modes, leading to a monotonically falling density profile.

Sengupta, M.; Ganesh, R. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)] [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

2014-02-15T23:59:59.000Z

302

Reducing dust emissions at OAO Alchevskkoks coke battery 10A  

SciTech Connect (OSTI)

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

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

2009-07-15T23:59:59.000Z

303

Rapid Extraction of Dust Impact Tracks from Silica Aerogel by Ultrasonic Micro-blades  

SciTech Connect (OSTI)

In January 2006, NASA's Stardust Mission will return with its valuable cargo of cometary dust particles, the first brought back to Earth, captured at hypervelocity speeds in silica aerogel collectors. Aerogel, a proven capture medium, is also a candidate for future sample return missions and low-earth orbit (LEO) deployments. Critical to the science return of Stardust and future missions using aerogel is the ability to efficiently extract impacted particles from collector tiles. Researchers will be eager to obtain Stardust samples as quickly as possible, and tools for the rapid extraction of particle impact tracks that require little construction, training, or investment would be an attractive asset. To this end, we have experimented with diamond and steel micro-blades. Applying ultrasonic frequency oscillations to these micro-blades via a piezo-driven holder produces rapid, clean cuts in the aerogel with minimal damage to the surrounding collector tile. With this approach, impact tracks in aerogel fragments with low-roughness cut surfaces have been extracted from aerogel tiles flown on NASA's Orbital Debris Collector Experiment. The smooth surfaces produced during cutting reduce imaging artifacts during analysis by SEM. Some tracks have been dissected to expose the main cavity for eventual isolation of individual impact debris particles and further analysis by techniques such as TEM and nanoSIMS.

Ishii, H; Graham, G; Kearsley, A T; Grant, P G; Snead, C J; Bradley, J P

2005-02-17T23:59:59.000Z

304

Nondetection of impulsive radio signals from lightning in Martian dust storms using the radar receiver on  

E-Print Network [OSTI]

emission from a Martian dust storm that they attribute to the excitation of Schumann [1952] resonances

Gurnett, Donald A.

305

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

SciTech Connect (OSTI)

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.

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

306

Iron Speciation and Mixing in Single Aerosol Particles from the Asian Continental Outflow  

SciTech Connect (OSTI)

Bioavailable iron from atmospheric aerosol is an essential nutrient that can control oceanic productivity, thereby impacting the global carbon budget and climate. Particles collected on Okinawa Island during an atmospheric pollution transport event from China were analyzed using complementary single particle techniques to determine the iron source and speciation. Comparing the spatial distribution of iron within ambient particles and standard Asian mineral dust, it was determined that field-collected atmospheric Fe-containing particles have numerous sources, including anthropogenic sources such as coal combustion. Fe-containing particles were found to be internally mixed with secondary species such as sulfate, soot, and organic carbon. The mass weighted average Fe(II) fraction (defined as Fe(II)/[Fe(II)+Fe(III)]) was determined to be 0.33 {+-} 0.08. Within the experimental uncertainty, this value lies close to the range of 0.26-0.30 determined for representative Asian mineral dust. Previous studies have indicated that the solubility of iron from combustion is much higher than that from mineral dust. Therefore, chemical and/or physical differences other than oxidation state may help explain the higher solubility of iron in atmospheric particles.

Moffet, Ryan C.; Furutani, Hiroshi; Rodel, Tobias; Henn, Tobias R.; Sprau, Peter; Laskin, Alexander; Uematsu, Mitsuo; Gilles, Marry K.

2012-04-04T23:59:59.000Z

307

Magnetorotational instability in plasmas with mobile dust grains  

SciTech Connect (OSTI)

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

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

2013-03-15T23:59:59.000Z

308

Global trends in visibility: implications for dust sources  

E-Print Network [OSTI]

There is a large uncertainty in the relative roles of human land use, climate change and carbon dioxide fertilization in changing desert dust source strength over the past 100 years, and the overall sign of human impacts ...

Mahowald, N. M.; Ballantine, J.A.; Feddema, Johannes J.; Ramankutty, N.

2007-06-01T23:59:59.000Z

309

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,...

310

Dust-shell Universe in the modified gravity scenario  

E-Print Network [OSTI]

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.

Michael Maziashvili

2005-04-15T23:59:59.000Z

311

Dynamics of Carroll Particles  

E-Print Network [OSTI]

We investigate particles whose dynamics is invariant under the Carroll group. Although a single free such Carroll particle has no non-trivial dynamics (`the Carroll particle does not move') we show that there exists non-trivial dynamics for a set of interacting Carroll particles. Furthermore, we gauge the Carroll algebra and couple the Carroll particle to these gauge fields. It turns out that for such a coupled system even a single Carroll particle can have non-trivial dynamics.

Eric Bergshoeff; Joaquim Gomis; Giorgio Longhi

2014-05-31T23:59:59.000Z

312

ON THE INITIAL MASS FUNCTION OF LOW-METALLICITY STARS: THE IMPORTANCE OF DUST COOLING  

SciTech Connect (OSTI)

The first stars to form in the universe are believed to have distribution of masses biased toward massive stars. This contrasts with the present-day initial mass function, which has a predominance of stars with masses lower than 1 M{sub Sun }. Therefore, the mode of star formation must have changed as the universe evolved. Such a transition is attributed to a more efficient cooling provided by increasing metallicity. Especially dust cooling can overcome the compressional heating, which lowers the gas temperature thus increasing its instability to fragmentation. The purpose of this paper is to verify if dust cooling can efficiently cool the gas, and enhance the fragmentation of gas clouds at the early stages of the universe. To confirm that, we calculate a set of hydrodynamic simulations that include sink particles, which represent contracting protostars. The thermal evolution of the gas during the collapse is followed by making use of a primordial chemical network and also a recipe for dust cooling. We model four clouds with different amounts of metals (10{sup -4}, 10{sup -5}, 10-6 Z{sub Sun }, and 0), and analyze how this property affect the fragmentation of star-forming clouds. We find evidence for fragmentation in all four cases, and hence conclude that there is no critical metallicity below which fragmentation is impossible. Nevertheless, there is a clear change in the behavior of the clouds at Z {approx}< 10{sup -5} Z{sub Sun }, caused by the fact that at this metallicity, fragmentation takes longer to occur than accretion, leading to a flat mass function at lower metallicities.

Dopcke, Gustavo [Member of the International Max Planck Research School for Astronomy and Cosmic Physics at the University of Heidelberg, IMPRS-HD, Germany. (Germany)] [Member of the International Max Planck Research School for Astronomy and Cosmic Physics at the University of Heidelberg, IMPRS-HD, Germany. (Germany); Glover, Simon C. O.; Clark, Paul C.; Klessen, Ralf S., E-mail: gustavo@uni-hd.de [Zentrum fuer Astronomie, Institut fuer Theoretische Astrophysik, Universitaet Heidelberg, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany)

2013-04-01T23:59:59.000Z

313

Dust size distribution and concentrations with cottonseed oil mills  

E-Print Network [OSTI]

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...

Wiederhold, Lee Roy

1976-01-01T23:59:59.000Z

314

Particle Physics Booklet 2008  

E-Print Network [OSTI]

212 25. Accelerator physics of colliders ? 26. High-energythe full Review. PARTICLE PHYSICS BOOKLET TABLE OF CONTENTSrev. ) Summary Tables of Particle Physics Gauge and Higgs

et al., C. Amsler

2008-01-01T23:59:59.000Z

315

Extraplanar Dust in Spiral Galaxies: Observations and Implications  

E-Print Network [OSTI]

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.

J. Christopher Howk

1999-10-05T23:59:59.000Z

316

HTGR Dust Safety Issues and Needs for Research and Development  

SciTech Connect (OSTI)

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

Paul W. Humrickhouse

2011-06-01T23:59:59.000Z

317

Understanding environmental leachability of electric arc furnace dust  

SciTech Connect (OSTI)

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.

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

2000-02-01T23:59:59.000Z

318

Development of materials resistant to metal dusting degradation.  

SciTech Connect (OSTI)

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

Natesan, K.; Zeng, Z.

2006-04-24T23:59:59.000Z

319

Airborne coal dust reduction in Romanian power plants  

SciTech Connect (OSTI)

Romanian power plant coal handling and preparation areas have not introduced adequate dust collection systems. Therefore, the measurement of airborne coal dust shows that these values are higher than the maximum allowable value under Romanian regulations. The author`s company has been testing a dry dust collection system formed by a ductwork/bagfilter/exhaust fan system. The system was installed at a coal transfer point with a drop height of about 10 meters. The quantity of extracted and cleaned air was about 5,000 m{sup 3}/hr. The airborne dust concentration in the exhausted air was under 4 mg/m{sup 3}. Due to an inadequate skirtboard design that did not prove airtight, there was not enough negative pressure in the containment region. The dust collection system efficiency will be improved with design modifications and tested again. The results have shown that the system can be an efficient solution for local dust collection in power plant coal handling facilities.

Matei, M.; Renel, I. [Energy Research and Modernizing Inst., Bucharest (Romania)

1994-12-31T23:59:59.000Z

320

PANIC ATTACKS QUICK! Your heart is pounding, your chest aches, you can't catch a breath or swallow, your  

E-Print Network [OSTI]

PANIC ATTACKS QUICK! Your heart is pounding, your chest aches, you can't catch a breath or swallow you feel you may go crazy, pass out, or die. What's wrong? Heart attacks? You've fallen in love? Well, maybe. But what you may be experiencing is a panic attack. What is a panic attack? You may have had

Kasman, Alex

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


321

Local governments are taking climate action plans to a new leve ont holil \\()ur breath waiting for a new  

E-Print Network [OSTI]

Local governments are taking climate action plans to a new leve ont holil \\()ur breath waiting-Los Angeles. Where climate planning is taking place is also notable. "It's not just a Left Coast acdvity and an energy-efficient hous- ing stock." And, she adds, "you don't have to be an environmentalist to support

Handy, Susan L.

322

Interaction of light with the ZnO surface: Photon induced oxygen "breathing," oxygen vacancies, persistent photoconductivity,  

E-Print Network [OSTI]

Interaction of light with the ZnO surface: Photon induced oxygen "breathing," oxygen vacancies donation of oxygen vacancies. Our findings suggest that the observed decomposition of the ZnO lattice may. The formation of oxygen-vacancy rich surface is suggested to induce surface delta doping, causing accumulation

Shalish, Ilan

323

Localized breathing solutions for BoseEinstein condensates in periodic traps. R. CarreteroGonzalez # and K. Promislow  

E-Print Network [OSTI]

Localized breathing solutions for Bose­Einstein condensates in periodic traps. R. Carretero6, Canada (June 1, 2001) We consider Bose­Einstein condensates confined by a pe­ riodic potential­ Einstein condensates (BECs) has triggered a vast inter­ est in the physics community. Novel techniques

324

EAF dust as an electrolytic zinc resource  

SciTech Connect (OSTI)

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.

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

1995-12-31T23:59:59.000Z

325

Energy conditions, traversable wormholes and dust shells  

E-Print Network [OSTI]

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

Francisco S. N. Lobo

2004-10-18T23:59:59.000Z

326

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

E-Print Network [OSTI]

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 ...

Pierce, J. R.

327

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

E-Print Network [OSTI]

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.

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

2010-01-01T23:59:59.000Z

328

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

SciTech Connect (OSTI)

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.

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

329

Rapid Automated Treatment Planning Process to Select Breast Cancer Patients for Active Breathing Control to Achieve Cardiac Dose Reduction  

SciTech Connect (OSTI)

Purpose: To evaluate a rapid automated treatment planning process for the selection of patients with left-sided breast cancer for a moderate deep inspiration breath-hold (mDIBH) technique using active breathing control (ABC); and to determine the dose reduction to the left anterior descending coronary artery (LAD) and the heart using mDIBH. Method and Materials: Treatment plans were generated using an automated method for patients undergoing left-sided breast radiotherapy (n = 53) with two-field tangential intensity-modulated radiotherapy. All patients with unfavorable cardiac anatomy, defined as having >10 cm{sup 3} of the heart receiving 50% of the prescribed dose (V{sub 50}) on the free-breathing automated treatment plan, underwent repeat scanning on a protocol using a mDIBH technique and ABC. The doses to the LAD and heart were compared between the free-breathing and mDIBH plans. Results: The automated planning process required approximately 9 min to generate a breast intensity-modulated radiotherapy plan. Using the dose-volume criteria, 20 of the 53 patients were selected for ABC. Significant differences were found between the free-breathing and mDIBH plans for the heart V{sub 50} (29.9 vs. 3.7 cm{sup 3}), mean heart dose (317 vs. 132 cGy), mean LAD dose (2,047 vs. 594 cGy), and maximal dose to 0.2 cm{sup 3} of the LAD (4,155 vs. 1,507 cGy, all p <.001). Of the 17 patients who had a breath-hold threshold of {>=}0.8 L, 14 achieved a {>=}90% reduction in the heart V{sub 50} using the mDIBH technique. The 3 patients who had had a breath-hold threshold <0.8 L achieved a lower, but still significant, reduction in the heart V{sub 50}. Conclusions: A rapid automated treatment planning process can be used to select patients who will benefit most from mDIBH. For selected patients with unfavorable cardiac anatomy, the mDIBH technique using ABC can significantly reduce the dose to the LAD and heart, potentially reducing the cardiac risks.

Wang Wei; Purdie, Thomas G. [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Rahman, Mohammad; Marshall, Andrea [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Liu Feifei [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Fyles, Anthony, E-mail: anthony.fyles@rmp.uhn.on.ca [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada)

2012-01-01T23:59:59.000Z

330

Clinical Results of Image-Guided Deep Inspiration Breath Hold Breast Irradiation  

SciTech Connect (OSTI)

Purpose: To evaluate the feasibility, cardiac dose reduction, and the influence of the setup error on the delivered dose for fluoroscopy-guided deep inspiration breath hold (DIBH) irradiation using a cone-beam CT for irradiation of left-sided breast cancer patients. Methods and Materials: Nineteen patients treated according to the DIBH protocol were evaluated regarding dose to the ipsilateral breast (or thoracic wall), heart, (left ventricle [LV]and left anterior descending artery [LAD]), and lung. The DIBH treatment plan was compared to the free-breathing (FB) treatment planning and to the dose data in which setup error was taken into account (i.e., actual delivered dose). Results: The largest setup variability was observed in the direction perpendicular to the RT field ({mu} = -0.8 mm, {Sigma} = 2.9 mm, {sigma} = 2.0 mm). The mean (D{sub mean}) and maximum (D{sub max}) doses of the DIBH treatment plan was significantly lower compared with the FB treatment plan for the heart (34% and 25%, p < 0.001), LV (71% and 28%, p < 0.001), and LAD (52% and 39.8%, p < 0.001). For some patients, large differences were observed between the heart D{sub max} according to the DIBH treatment plan and the actual delivered dose (up to 71%), although D{sub max} was always smaller than the planned FB dose (mean group reduction = 29%, p < 0.001). Conclusion: The image-guided DIBH treatment protocol is a feasible irradiation method with small setup variability that significantly reduces the dose to the heart, LV, and LAD.

Borst, Gerben R.; Sonke, Jan-Jakob; Hollander, Suzanne den; Betgen, Anja; Remeijer, Peter; Giersbergen, Aline van; Russell, Nicola S.; Elkhuizen, Paula H.M.; Bartelink, Harry [Department of Radiation Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Vliet-Vroegindeweij, Corine van, E-mail: C.v.vliet@nki.n [Department of Radiation Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands)

2010-12-01T23:59:59.000Z

331

Lack of Correlation Between External Fiducial Positions and Internal Tumor Positions During Breath-Hold CT  

SciTech Connect (OSTI)

Purpose: For thoracic tumors, if four-dimensional computed tomography (4DCT) is unavailable, the internal margin can be estimated by use of breath-hold (BH) CT scans acquired at end inspiration (EI) and end expiration (EE). By use of external surrogates for tumor position, BH accuracy is estimated by minimizing the difference between respiratory extrema BH and mean equivalent-phase free breathing (FB) positions. We tested the assumption that an external surrogate for BH accuracy correlates with internal tumor positional accuracy during BH CT. Methods and Materials: In 16 lung cancer patients, 4DCT images, as well as BH CT images at EI and EE, were acquired. Absolute differences between BH and mean equivalent-phase (FB) positions were calculated for both external fiducials and gross tumor volume (GTV) centroids as metrics of external and internal BH accuracy, respectively, and the results were correlated. Results: At EI, the absolute difference between mean FB and BH fiducial displacement correlated poorly with the absolute difference between FB and BH GTV centroid positions on CT images (R{sup 2} = 0.11). Similarly, at EE, the absolute difference between mean FB and BH fiducial displacements correlated poorly with the absolute difference between FB and BH GTV centroid positions on CT images (R{sup 2} = 0.18). Conclusions: External surrogates for tumor position are not an accurate metric of BH accuracy for lung cancer patients. This implies that care should be taken when using such an approach because an incorrect internal margin could be generated.

Hunjan, Sandeep, E-mail: shunjan@mdanderson.or [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Starkschall, George; Prado, Karl; Dong Lei; Balter, Peter [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)

2010-04-15T23:59:59.000Z

332

Development of materials resistant to metal dusting degradation.  

SciTech Connect (OSTI)

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

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

2007-12-07T23:59:59.000Z

333

Investigation of the sheath formation in a dusty plasma containing energetic electrons and nano-size dust grains  

SciTech Connect (OSTI)

Numerical simulations of the stationary multi-fluid equations are used to study the structure of a dusty plasma sheath in the presence of a beam of energetic electrons. It is found that even a small number of energetic electrons can strongly modify the sheath parameters, specially the sheath thickness. Depending on the magnitude of the beam flux, two different regimes of sheath thickness can be recognized; At small beam fluxes, the sheath is in the regime of thin sheath and its thickness grows linearly with the beam flux. As the beam flux increases, at a certain beam energy or beam number density, the sheath demonstrates a sharp transition to the regime of thick sheath where the width is almost three times larger. The beam parameters corresponding to the transition between the two regimes depend on the parameters of the background plasma. The beam transition energy increases with the electron temperature and dust number density while decreases with the dust radius. On the other hand, the beam transition number density is a non-monotonic function of the background plasma number density. The localization of dust particles above the substrate is intensified by the increase in the beam number density.

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

2012-10-15T23:59:59.000Z

334

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

E-Print Network [OSTI]

curves of dry-generated Solvay calcium carbonate, BakerSEM images of Baker and Solvay dry calcite powders dispersedand atomized Solvay calcite. ………..…………………………………………………………

Sullivan, Ryan Christopher

2008-01-01T23:59:59.000Z

335

Application of spheroid models to account for aerosol particle nonsphericity in remote sensing of desert dust  

E-Print Network [OSTI]

Mishchenko,4 Ping Yang,5 Tom F. Eck,1,6 Hester Volten,7 Olga Mun~oz,8 Ben Veihelmann,9 Wim J. van der Zande arranged into a software package, which allows fast, accurate, and flexible modeling of scattering model and explore the possibility of aerosol shape identification, the software tool has been integrated

336

Dust properties inside molecular clouds from coreshine modeling and observations  

E-Print Network [OSTI]

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...

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

337

Laser particle sorter  

DOE Patents [OSTI]

Method and apparatus are provided for sorting particles, such as biological particles. A first laser is used to define an optical path having an intensity gradient which is effective to propel the particles along the path but which is sufficiently weak that the particles are not trapped in an axial direction. A probe laser beam is provided for interrogating the particles to identify predetermined phenotypical characteristics of the particles. A second laser beam is provided to intersect the driving first laser beam, wherein the second laser beam is activated by an output signal indicative of a predetermined characteristic. The second laser beam is switchable between a first intensity and a second intensity, where the first intensity is effective to displace selected particles from the driving laser beam and the second intensity is effective to propel selected particles along the deflection laser beam. The selected particles may then be propelled by the deflection beam to a location effective for further analysis. 2 figs.

Martin, J.C.; Buican, T.N.

1987-11-30T23:59:59.000Z

338

Why do Particle Clouds Generate Electric Charges?  

E-Print Network [OSTI]

Grains in desert sandstorms spontaneously generate strong electrical charges; likewise volcanic dust plumes produce spectacular lightning displays. Charged particle clouds also cause devastating explosions in food, drug, and coal processing industries. Despite the wide-ranging importance of granular charging in both nature and industry, even the simplest aspects of its causes remain elusive, for it is difficult to understand how inert grains in contact with little more than other inert grains can generate the large charges observed. In this paper, we present a simple yet predictive explanation for the charging of granular materials in collisional flows. We argue from very basic considerations that charge transfer can be expected in collisions of identical dielectric grains, and we confirm the model's predictions using discrete element simulations and a tabletop granular experiment.

T. Pähtz; H. J. Herrmann; T. Shinbrot

2010-03-26T23:59:59.000Z

339

Why do Particle Clouds Generate Electric Charges?  

E-Print Network [OSTI]

Grains in desert sandstorms spontaneously generate strong electrical charges; likewise volcanic dust plumes produce spectacular lightning displays. Charged particle clouds also cause devastating explosions in food, drug and coal processing industries. Despite the wide-ranging importance of granular charging in both nature and industry, even the simplest aspects of its causes remain elusive, because it is difficult to understand how inert grains in contact with little more than other inert grains can generate the large charges observed. Here, we present a simple yet predictive explanation for the charging of granular materials in collisional flows. We argue from very basic considerations that charge transfer can be expected in collisions of identical dielectric grains in the presence of an electric field, and we confirm the model's predictions using discrete-element simulations and a tabletop granular experiment.

T. Pähtz; H. J. Herrmann; T. Shinbrot

2015-03-16T23:59:59.000Z

340

Lithium Wall Conditioning And Surface Dust Detection On NSTX  

SciTech Connect (OSTI)

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

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

2011-05-23T23:59:59.000Z

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


341

VARIABLE WINDS AND DUST FORMATION IN R CORONAE BOREALIS STARS  

SciTech Connect (OSTI)

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.

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

342

Analysis of peak characterization and data alignment of a differential mobility spectrometer for the discovery of TB biomarkers in human breath  

E-Print Network [OSTI]

Biomarkers have become a growing field for disease research and diagnostics. For the infectious, deadly disease, tuberculosis (TB), the discovery of effective TB biomarkers in the human breath may enable the development ...

Tang, Amy Yuen-Lee

2008-01-01T23:59:59.000Z

343

The 10 $?$m infrared band of silicate dust: A laboratory study comparing the aerosol and KBr pellet techniques  

E-Print Network [OSTI]

The profile of the silicate 10 $\\mu$m IR band contains important information about the evolutional stage of dust in circumstellar environments and the possible ongoing process of planetesimal formation. In order to extract this information, the observed band profiles are compared with calculated or laboratory-measured absorption cross sections of amorphous and crystalline grains with different sizes and compositions. We present in this study the first laboratory measurements of the 10 $\\mu$m band profiles of nonembedded, i.e. free-flying, particles of amorphous and crystalline Mg$_2$SiO$_4$ (with two different particle shapes), amorphous and crystalline MgSiO$_3$, and crystalline olivine. We compare the spectra with those measured on embedded grains and discuss the potential of the new experimental method for comparison with observed spectra, as well as for future studies of agglomeration and surface manipulation of the grains.

A. Tamanai; H. Mutschke; J. Blum; G. Meeus

2006-09-08T23:59:59.000Z

344

The 10 $\\mu$m infrared band of silicate dust: A laboratory study comparing the aerosol and KBr pellet techniques  

E-Print Network [OSTI]

The profile of the silicate 10 $\\mu$m IR band contains important information about the evolutional stage of dust in circumstellar environments and the possible ongoing process of planetesimal formation. In order to extract this information, the observed band profiles are compared with calculated or laboratory-measured absorption cross sections of amorphous and crystalline grains with different sizes and compositions. We present in this study the first laboratory measurements of the 10 $\\mu$m band profiles of nonembedded, i.e. free-flying, particles of amorphous and crystalline Mg$_2$SiO$_4$ (with two different particle shapes), amorphous and crystalline MgSiO$_3$, and crystalline olivine. We compare the spectra with those measured on embedded grains and discuss the potential of the new experimental method for comparison with observed spectra, as well as for future studies of agglomeration and surface manipulation of the grains.

Tamanai, A; Blum, J; Meeus, G

2006-01-01T23:59:59.000Z

345

Inorganic composition of fine particles in mixed mineral dustpollution plumes observed from airborne measurements during ACE-Asia  

E-Print Network [OSTI]

of the atmosphere (2419, 2427); 0345 Atmospheric Composition and Structure: Pollution--urban and regional (0305Inorganic composition of fine particles in mixed mineral dust­pollution plumes observed from of Earth and Atmospheric Science, Georgia Institute of Technology, Atlanta, Georgia, USA G. R. Carmichael

Weber, Rodney

346

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

E-Print Network [OSTI]

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...

Whitelock, Derek Paul

1994-01-01T23:59:59.000Z

347

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

E-Print Network [OSTI]

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

Ai, Ning, 1978-

2003-01-01T23:59:59.000Z

348

E-Print Network 3.0 - asymmetric dust shell Sample Search Results  

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

that this is thermal emission from silicate dust that con- densed out in the red giant wind of the progenitor star... . The dust temperature is 166 18 12 K, and the emitting...

349

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

SciTech Connect (OSTI)

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.

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

350

E-Print Network 3.0 - agricultural dust exposure Sample Search...  

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

such as dust mites or cockroach-related allergens (Finn et al. 2000; Platts... (e.g., a house-dust or passive air sample) might be an appropriate measure of exposure for use......

351

Tumor Tracking Method Based on a Deformable 4D CT Breathing Motion Model Driven by an External Surface Surrogate  

SciTech Connect (OSTI)

Purpose: To develop a tumor tracking method based on a surrogate-driven motion model, which provides noninvasive dynamic localization of extracranial targets for the compensation of respiration-induced intrafraction motion in high-precision radiation therapy. Methods and Materials: The proposed approach is based on a patient-specific breathing motion model, derived a priori from 4-dimensional planning computed tomography (CT) images. Model parameters (respiratory baseline, amplitude, and phase) are retrieved and updated at each treatment fraction according to in-room radiography acquisition and optical surface imaging. The baseline parameter is adapted to the interfraction variations obtained from the daily cone beam (CB) CT scan. The respiratory amplitude and phase are extracted from an external breathing surrogate, estimated from the displacement of the patient thoracoabdominal surface, acquired with a noninvasive surface imaging device. The developed method was tested on a database of 7 lung cancer patients, including the synchronized information on internal and external respiratory motion during a CBCT scan. Results: About 30 seconds of simultaneous acquisition of CBCT and optical surface images were analyzed for each patient. The tumor trajectories identified in CBCT projections were used as reference and compared with the target trajectories estimated from surface displacement with the a priori motion model. The resulting absolute differences between the reference and estimated tumor motion along the 2 image dimensions ranged between 0.7 and 2.4 mm; the measured phase shifts did not exceed 7% of the breathing cycle length. Conclusions: We investigated a tumor tracking method that integrates breathing motion information provided by the 4-dimensional planning CT with surface imaging at the time of treatment, representing an alternative approach to point-based external–internal correlation models. Although an in-room radiograph-based assessment of the reliability of the motion model is envisaged, the developed technique does not involve the estimation and continuous update of correlation parameters, thus requiring a less intense use of invasive imaging.

Fassi, Aurora, E-mail: aurora.fassi@mail.polimi.it [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Schaerer, Joël; Fernandes, Mathieu [CREATIS, CNRS UMR 5220, INSERM U1044, Université Lyon 1, INSA-Lyon, Villeurbanne (France); Department of Radiotherapy, Centre Léon Bérard, Lyon (France); Riboldi, Marco [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Bioengineering Unit, CNAO Foundation, Pavia (Italy); Sarrut, David [CREATIS, CNRS UMR 5220, INSERM U1044, Université Lyon 1, INSA-Lyon, Villeurbanne (France); Department of Radiotherapy, Centre Léon Bérard, Lyon (France); Baroni, Guido [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Bioengineering Unit, CNAO Foundation, Pavia (Italy)

2014-01-01T23:59:59.000Z

352

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)

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.

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

353

An investigation of dust storm generation in the Southern Great Plains  

E-Print Network [OSTI]

An investigation of dust sto'rms in the Southern Great Plains was conducted to determine correlations between dust and precipitation, Antecedent Precipitation Index (API), wind, time of occurrence, and dew-point depression. Re- lationships between blowing dust... Summary of favorable parameters and conditions for springtime generation of blowing dust in local areas of the Southern Great Plains 66 LIST OF FIGURES Figure Title Page Physiographic regions of the United States and their dominant landf orms (after...

Pollard, Marshall Conrad

1977-01-01T23:59:59.000Z

354

Solubility testing of actinides on breathing-zone and area air samples  

SciTech Connect (OSTI)

A solubility testing method for several common actinides has been developed with sufficient sensitivity to allow profiles to be determined from routine breathing zone and area air samples in the workplace. Air samples are covered with a clean filter to form a filter-sample-filter sandwich which is immersed in an extracellular lung serum simulant solution. The sample is moved to a fresh beaker of the lung fluid simulant each day for one week, and then weekly until the end of the 28 day test period. The soak solutions are wet ashed with nitric acid and hydrogen peroxide to destroy the organic components of the lung simulant solution prior to extraction of the nuclides of interest directly into an extractive scintillator for subsequent counting on a Photon-Electron Rejecting Alpha Liquid Scintillation (PERALS{reg_sign}) spectrometer. Solvent extraction methods utilizing the extractive scintillators have been developed for the isotopes of uranium, plutonium, and curium. The procedures normally produce an isotopic recovery greater than 95% and have been used to develop solubility profiles from air samples with 40 pCi or less of U{sub 3}O{sub 8}. Profiles developed for U{sub 3}O{sub 8} samples show good agreement with in vitro and in vivo tests performed by other investigators on samples from the same uranium mills.

Metzger, R.L.; Jessop, B.H.; McDowell, B.L. [Radiation Safety Engineering, Inc., Chandler, AZ (United States)

1996-02-01T23:59:59.000Z

355

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

SciTech Connect (OSTI)

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

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

2011-11-29T23:59:59.000Z

356

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

SciTech Connect (OSTI)

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

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

2011-11-29T23:59:59.000Z

357

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

E-Print Network [OSTI]

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

Rycroft, Chris H.

358

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

E-Print Network [OSTI]

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

Clarke, Michèle

359

The global distribution of mineral dust and its impacts on the climate system: A review  

E-Print Network [OSTI]

radiation budget and hydrological cycle through their radiative and cloud condensation nucleus effects of an intercontinental scale, including North African dust plumes over the Atlantic Ocean, summer dust plumes from the Arabian Peninsula over the Arabian Sea and Indian Ocean and spring dust plumes from East Asia over

Hickman, Mark

360

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

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


361

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

362

Dust in the Earth system: The biogeochemical linking of land, air, and  

E-Print Network [OSTI]

1 Dust in the Earth system: The biogeochemical linking of land, air, and sea Andy Ridgwell1 of CO2 from the atmosphere. The complex way in which dust biogeochemically links land, air, and sea of atmospheric aerosols. In this review, however, we consider dust to be soil mineral fragments. The entrainment

Kohfeld, Karen

363

The Influence of Dust on the Absorptivity of Radiant Barriers  

E-Print Network [OSTI]

The purpose of this project was to model and quantify the increase of the absorptivity of radiant barriers caused by the accumulation of dust on the surface of radiant barriers. This research was the continuation of a previous work by the author...

Noboa, Homero L.

364

Morphological Investigations of Fibrogenic Action of Estonian Oil Shale Dust  

E-Print Network [OSTI]

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

V. A. Kung

365

The dust and gas content of the Crab Nebula  

E-Print Network [OSTI]

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...

Owen, P J

2015-01-01T23:59:59.000Z

366

Global observations of desert dust and biomass burning aerosols  

E-Print Network [OSTI]

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

Graaf, Martin de

367

The AIR, the WATER, the SUN, the DUST,  

E-Print Network [OSTI]

to chemicals on the job or elsewhere in the environment. Researchers at The National Institute of Environmental#12;The AIR, the WATER, the SUN, the DUST, PLANTS and ANIMALS, and the CHEMICALS and METALS of our also make some people sick.Here are some diseases that are related to your Allergies and Asthma (AZ

Bandettini, Peter A.

368

Destruction of Interstellar Dust in Evolving Supernova Remnant Shock Waves  

E-Print Network [OSTI]

Supernova generated shock waves are responsible for most of the destruction of dust grains in the interstellar medium (ISM). Calculations of the dust destruction timescale have so far been carried out using plane parallel steady shocks, however that approximation breaks down when the destruction timescale becomes longer than that for the evolution of the supernova remnant (SNR) shock. In this paper we present new calculations of grain destruction in evolving, radiative SNRs. To facilitate comparison with the previous study by Jones et al. (1996), we adopt the same dust properties as in that paper. We find that the efficiencies of grain destruction are most divergent from those for a steady shock when the thermal history of a shocked gas parcel in the SNR differs significantly from that behind a steady shock. This occurs in shocks with velocities >~ 200 km/s for which the remnant is just beginning to go radiative. Assuming SNRs evolve in a warm phase dominated ISM, we find dust destruction timescales are incre...

Slavin, Jonathan D; Jones, Anthony P

2015-01-01T23:59:59.000Z

369

WEATHER MODIFICATION BY CARBON DUST ABSORPTION OF SOLAR ENERGY  

E-Print Network [OSTI]

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

Gray, William

370

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...

371

Adhesive particle shielding  

DOE Patents [OSTI]

An efficient device for capturing fast moving particles has an adhesive particle shield that includes (i) a mounting panel and (ii) a film that is attached to the mounting panel wherein the outer surface of the film has an adhesive coating disposed thereon to capture particles contacting the outer surface. The shield can be employed to maintain a substantially particle free environment such as in photolithographic systems having critical surfaces, such as wafers, masks, and optics and in the tools used to make these components, that are sensitive to particle contamination. The shield can be portable to be positioned in hard-to-reach areas of a photolithography machine. The adhesive particle shield can incorporate cooling means to attract particles via the thermophoresis effect.

Klebanoff, Leonard Elliott (Dublin, CA); Rader, Daniel John (Albuquerque, NM); Walton, Christopher (Berkeley, CA); Folta, James (Livermore, CA)

2009-01-06T23:59:59.000Z

372

Simulation of particle agglomeration using dissipative particle dynamics  

E-Print Network [OSTI]

Attachment of particles to one another due to action of certain inter-particle forces is called as particle agglomeration. It has applications ranging from efficient capture of ultra-fine particles generated in coal-burning boilers to effective...

Mokkapati, Srinivas Praveen

2009-05-15T23:59:59.000Z

373

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

374

Three-dimensional instability of dust ion-acoustic solitary waves in a magnetized dusty plasma with two different types of nonisothermal electrons  

SciTech Connect (OSTI)

The nonlinear propagation of dust ion-acoustic solitary waves (DIASWs) in a magnetized dusty plasma which consists of two different types of nonisothermal electrons, hot adiabatic inertial ions fluid and immobile negatively charged dust particles is studied. The modified Zakharov-Kuznetsov (MZK) equation, describing the small but finite amplitude DIASWs, is derived using a reductive perturbation method. The combined effects of the external magnetic field, obliqueness (i.e., the propagation angle), and the two-temperature nonisothermal electrons, which are found to significantly modify the basic properties of DIASWs, are explicitly examined. The three-dimensional instability of DIASWs is also analyzed using the small-k (long wavelength plane wave) perturbation expansion technique. The results show that the external magnetic field, the propagation angle, and the two-temperature nonisothermal electrons have strong effects on the instability criterion as well as the growth rate.

Shalaby, M.; Khaled, M. A. [Department of Physics, Faculty of Science, Ain Shams University, Cairo, 11566 (Egypt); EL-Labany, S. K.; EL-Shamy, E. F. [Department of Physics, Faculty of Science, Mansoura University, Damietta Branch, Damietta El-Gedida 34517 (Egypt)

2010-11-15T23:59:59.000Z

375

On the AU Mic debris disk: density profiles, grain properties and dust dynamics  

E-Print Network [OSTI]

We present the first comprehensive analysis of the AU Mic debris disk properties since the system was discovered by Kalas et al. (2004), and we explore whether the dynamical model, successful to reproduce the Beta Pic brightness profile could apply to AU Mic. We calculate the surface density profile of the AU Mic disk by performing the inversion of the near-IR and visible scattered light brightness profiles measured by Liu (2004a) and Krist et al. (2005), respectively. We discuss the grain properties by analysing the blue color of the disk in the visible (Krist et al. 2005) and by fitting the disk spectral energy distribution. We show that irrespective of the mean scattering asymmetry factor of the grains, most of the emission arises from an asymmetric, collisionally-dominated region that peaks close to the surface brightness break around 35 AU. The elementary scatterers at visible wavelengths are found to be sub-micronic, but the inferred size distribution underestimates the amount of large grains, resulting in too low sub-millimeter emissions compared to the observations. From our inversion procedure, we find that the V- to H-band scattering cross sections ratio increases outside 40 AU, in line with the observed color gradient of the disk. We show that a standard, solar-like stellar wind generates a pressure force onto the dust particles that behaves much like a radiation pressure force. With an assumed Mdot ~ 300 Mdot_sun, the wind pressure overcomes the radiation pressure and this effect is enhanced by the stellar flares. This explains the similarity between the Beta Pic and AU Mic brightness profiles. In both cases, the color gradient beyond 120 AU for Beta Pic and 35 AU for AU Mic, is believed to be a direct consequence of the dust dynamics.

J. C. Augereau; H. Beust

2006-04-13T23:59:59.000Z

376

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

SciTech Connect (OSTI)

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

Carter, C M

2012-04-25T23:59:59.000Z

377

Collector sealants and breathing. Final Report, 25 September 1978-31 December 1979  

SciTech Connect (OSTI)

The objectives of this program were: (1) to investigate the pertinent properties of a variety of possible sealants for solar collectors and identify the most promising candidates, and (2) to study the effect of breathing in flat-plate, thermal solar collector units. The study involved two types of sealants, Class PS which includes preformed seals or gaskets and Class SC which includes sealing compounds or caulks. It was the intent of the study to obtain data regarding initial properties of candidate elastomers from manufacturers and from the technical literature and to use those sources to provide data pertaining to endurance of these materials under environmental service conditions. Where necessary, these data were augmented by experimental measurements. Environmental stresses evaluated by these measurements included elevated temperatures, moisture, ultraviolet light, ozone and oxygen, and fungus. The second major area of the work involved a study of the effects of materials used and design on the durability of solar collectors. Factors such as design, fabrication, materials of construction, seals and sealing techniques and absorber plate coatings were observed on actual field units removed from service. Such phenomena as leakage, corrosion and formation of deposits on glazing and absorber plate were noted. An evaluation of the properties of several desiccants was made in order to providemeans to mitigate the deleterious effects of water on collector life. Adsorbents for organic degradation products of sealants were also investigated in order to protect the glazing and absorber plate from deposited coatings. Since adsorbents and desiccants in general tend to take up both water and organic decomposition products, relative affinities of a number of these agents for water and for organic compounds were determined . Results are presented in detail.

Mendelsohn, M A; Luck, R M; Yeoman, F A; Navish, Jr, F W

1980-02-20T23:59:59.000Z

378

MIE and Flame velocity of partially oxidised aluminium dust Stphane Bernard, Philippe Gillard, Fabrice Foucher, Christine Mounam-Rousselle  

E-Print Network [OSTI]

present dust explosion hazards. The prevention of these hazards can be achieved by the characterisation in the oxide shell which increases the reactivity of the oxidised aluminium dust. Keywords : DUST EXPLOSIONSMIE and Flame velocity of partially oxidised aluminium dust Stéphane Bernard, Philippe Gillard

Paris-Sud XI, Université de

379

DUST EMISSION AND STAR FORMATION IN STEPHAN'S QUINTET  

SciTech Connect (OSTI)

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.

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

380

NBB Enclosed Particle Receiver  

Broader source: Energy.gov (indexed) [DOE]

rigorous NREL and recipient subcontracting processes. Goal: This project will develop a near-blackbody particle receiver and an integrated fluidized-bed heat exchanger to achieve...

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


381

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)

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.

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

382

Rapid estimation of 4DCT motion-artifact severity based on 1D breathing-surrogate periodicity  

SciTech Connect (OSTI)

Purpose: Motion artifacts are common in patient four-dimensional computed tomography (4DCT) images, leading to an ill-defined tumor volume with large variations for radiotherapy treatment and a poor foundation with low imaging fidelity for studying respiratory motion. The authors developed a method to estimate 4DCT image quality by establishing a correlation between the severity of motion artifacts in 4DCT images and the periodicity of the corresponding 1D respiratory waveform (1DRW) used for phase binning in 4DCT reconstruction. Methods: Discrete Fourier transformation (DFT) was applied to analyze 1DRW periodicity. The breathing periodicity index (BPI) was defined as the sum of the largest five Fourier coefficients, ranging from 0 to 1. Distortional motion artifacts (excluding blurring) of cine-scan 4DCT at the junctions of adjacent couch positions around the diaphragm were classified in three categories: incomplete, overlapping, and duplicate anatomies. To quantify these artifacts, discontinuity of the diaphragm at the junctions was measured in distance and averaged along six directions in three orthogonal views. Artifacts per junction (APJ) across the entire diaphragm were calculated in each breathing phase and phase-averaged APJ{sup ¯}, defined as motion-artifact severity (MAS), was obtained for each patient. To make MAS independent of patient-specific motion amplitude, two new MAS quantities were defined: MAS{sup D} is normalized to the maximum diaphragmatic displacement and MAS{sup V} is normalized to the mean diaphragmatic velocity (the breathing period was obtained from DFT analysis of 1DRW). Twenty-six patients’ free-breathing 4DCT images and corresponding 1DRW data were studied. Results: Higher APJ values were found around midventilation and full inhalation while the lowest APJ values were around full exhalation. The distribution of MAS is close to Poisson distribution with a mean of 2.2 mm. The BPI among the 26 patients was calculated with a value ranging from 0.25 to 0.93. The DFT calculation was within 3 s per 1DRW. Correlations were found between 1DRW periodicity and 4DCT artifact severity: ?0.71 for MAS{sup D} and ?0.73 for MAS{sup V}. A BPI greater than 0.85 in a 1DRW suggests minimal motion artifacts in the corresponding 4DCT images. Conclusions: The breathing periodicity index and motion-artifact severity index are introduced to assess the relationship between 1DRW and 4DCT. A correlation between 1DRW periodicity and 4DCT artifact severity has been established. The 1DRW periodicity provides a rapid means to estimate 4DCT image quality. The rapid 1DRW analysis and the correlative relationship can be applied prospectively to identify irregular breathers as candidates for breath coaching prior to 4DCT scan and retrospectively to select high-quality 4DCT images for clinical motion-management research.

Li, Guang, E-mail: lig2@mskcc.org; Caraveo, Marshall [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York 10065 (United States); Wei, Jie [Department of Computer Science, City College of New York, New York, New York 10031 (United States); Rimner, Andreas; Wu, Abraham J.; Goodman, Karyn A. [Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York 10065 (United States); Yorke, Ellen [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10065 (United States)

2014-11-01T23:59:59.000Z

383

Performance of hydroclones for removing particles from viscous liquids  

SciTech Connect (OSTI)

The performance of a 1-cm diam, Dorr-Oliver hydroclone with slurries containing approx. 5 wt % solids in water-glycerin solutions was studied to evaluate the effects of fluid viscosity. Micron-sized particles of low-density solids (aluminum oxide, test dust, fly ash, or kaolin) were removed from solutions with viscosities ranging from 1 to 85 cP. Pressure drop across the hydroclone increased with increasing feed rate and viscosity. Gross and centrifugal efficiencies were found to increase with flow rate and decrease with viscosity. Liquid viscosities >10 cP had deleterious effects on the pressure drop and efficiency; thus useful separations were not attained. The particle diameter, corresponding to a point efficiency of 50%, decreased as the product of the inlet Reynolds number and the solid-to-liquid density ratio increased. The reduced efficiency curve was found to characterize the hydroclone performance.

Talbot, J.B.

1980-08-01T23:59:59.000Z

384

Particle Concentration At Planet Induced Gap Edges and Vortices: I. Inviscid 3-D Hydro Disks  

E-Print Network [OSTI]

We perform a systematic study of the dynamics of dust particles in protoplanetary disks with embedded planets using global 2-D and 3-D inviscid hydrodynamic simulations. We implement Lagrangian particles into magnetohydrodynamic code Athena with cylindrical coordinates and explore the behavior of dust grains with sizes spanning more than 6 orders of magnitude --- from the well-coupled to decoupled limits. We find two distinct outcomes depending on the mass of the embedded planet, which is varied between 8 M_earth to 9 M_{J}. In the presence of a low mass planet (8 M_earth), two narrow gaps start to open in the gas on each side of the planet where the density waves shock. Although these gaps are quite shallow, they dramatically affect particle drift speed and cause significant, axisymmetric dust depletion near the planet. On the other hand, a more massive planet (>0.1 M_{J}) carves out a deeper gap with sharp edges, which are unstable to the formation of vortices that later merge into a single vortex. The vort...

Zhu, Zhaohuan; Rafikov, Roman R; Bai, Xuening

2013-01-01T23:59:59.000Z

385

BREATH Version 1.1, Coupled flow and energy transport in porous media: Simulator description and user guide  

SciTech Connect (OSTI)

This document describes the BREATH computer code, including the mathematical and numerical formulation for the simulator, usage description, and sample input files with corresponding output files. The BREATH computer code is designed to simulate one-dimensional flow of a liquid phase and dispersive transport of the corresponding vapor species, coupled with energy transfer, in a heterogeneous porous medium. The BREATH simulator has been developed for use in auxiliary analyses which are a part of the Nuclear Regulatory Commission Iterative Performance Assessment program. The simulator was developed in response to the observation from Total System Performance Assessments by both the Nuclear Regulatory Commission and the US Department of Energy that total-system performance at the Yucca Mountain site in Nevada is highly sensitive to the infiltration rate. Accordingly, this first version of the code is primarily intended to simulate processes important to infiltration and evaporation in climatic and hydrologic near-surface environments representative of the Yucca Mountain site. The simulation model assumes that there is an immobile solid phase, a mobile liquid phase, and an optional infinitely mobile gas phase. The liquid may have an associated vapor species, assumed to be in equilibrium with the liquid phase. The vapor phase may only move via diffusion within the gas phase. Energy may be transported in the form of enthalpy, thermal conduction, and latent heat. The temperature range is assumed to be between 0 and 100{degree}C. Available boundary conditions include six liquid-phase conditions, four vapor-species conditions, and three energy conditions, all of which may be applied independently to either end of the domain. Meteorological conditions may also be input, thereby providing additional control over boundary fluxes. Boundary conditions may be updated as often as desired.

Stothoff, S.A.

1995-07-01T23:59:59.000Z

386

Eight-year Climatology of Dust Optical Depth on Mars  

E-Print Network [OSTI]

We have produced a multiannual climatology of airborne dust from Martian year 24 to 31 using multiple datasets of retrieved or estimated column optical depths. The datasets are based on observations of the Martian atmosphere from April 1999 to July 2013 made by different orbiting instruments: the Thermal Emission Spectrometer (TES) aboard Mars Global Surveyor, the Thermal Emission Imaging System (THEMIS) aboard Mars Odyssey, and the Mars Climate Sounder (MCS) aboard Mars Reconnaissance Orbiter (MRO). The procedure we have adopted consists of gridding the available retrievals of column dust optical depth (CDOD) from TES and THEMIS nadir observations, as well as the estimates of this quantity from MCS limb observations. Our gridding method calculates averages and uncertainties on a regularly spaced, but possibly incomplete, spatio-temporal grid, using an iterative procedure weighted in space, time, and retrieval uncertainty. In order to evaluate strengths and weaknesses of the resulting gridded maps, we validat...

Montabone, L; Millour, E; Wilson, R J; Lewis, S R; Cantor, B A; Kass, D; Kleinboehl, A; Lemmon, M; Smith, M D; Wolff, M J

2014-01-01T23:59:59.000Z

387

Spectroscopic diagnostic for the mineralogy of large dust grains  

E-Print Network [OSTI]

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.

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

2003-10-30T23:59:59.000Z

388

Spherically symmetric cosmological spacetimes with dust and radiation — numerical implementation  

SciTech Connect (OSTI)

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.

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

389

Electromagnetic radiation, motion of a particle and energy-mass relation  

E-Print Network [OSTI]

Equation of motion of an uncharged arbitrarily shaped dust particle under the effects of (stellar) electromagnetic radiation and thermal emission is derived. The resulting relativistically covariant equation of motion is expressed in terms of standard optical parameters. Relations between energy and mass of the incoming and outgoing radiation are obtained, together with relations between radiation energy and mass of the particle. The role of the diffraction nicely fits the relativistic formulation of the momentum of the outgoing radiation. The inequality 0 < $\\bar{Q}'_{pr, 1} / \\bar{Q}'_{ext}$ < 2 is a simple relativistic consequence for the Poynting-Robertson (P-R) effect ($\\bar{Q}'_{ext}$ and $\\bar{Q}'_{pr, 1}$ are dimensionless efficiency factors for the extinction and radial direction of the radiation pressure, integrated over stellar spectrum). The condition for the P-R effect is $\\vec{p}'_{o}$ = (1 - $\\bar{Q}'_{pr, 1} / \\bar{Q}'_{ext}$) $\\vec{p}'_{i}$, where $\\vec{p}'_{i}$ and $\\vec{p}'_{o}$ are incoming and outgoing radiation momenta (per unit time) measured in the proper frame of reference of the particle. The case of "perfectly absorbing spherical dust particle", within geometrical optics approximation, corresponds to the condition $\\vec{p}'_{o}$ = 0.5 $\\vec{p}'_{i}$. As for arbitrarily shaped dust particle, the condition 0 < $\\bar{C}'_{pr, 1}$ / $\\bar{C}'_{ext}$ < 2 / ($1 ~+~ \\sum_{j=2}^{3} \\bar{C}'_{pr, j} / \\bar{C}'_{pr, 1}$) holds for cross sections of extinction and radiation pressure components. The condition can add a new information to the results obtained from observations, measurements and numerical calculations of the optical properties of the particle.

J. Klacka

2008-07-18T23:59:59.000Z

390

Modelling the effects of dust on galaxy spectra Miller Crawford  

E-Print Network [OSTI]

of a double exponential: ae d = ae 0 exp (\\GammaR=R d ) exp (\\Gammajzj=z d ) where z = r cos ` The bulge is given by a King profile: ae b = ae 0 h 1 + i r r c j 2 i \\Gammafl where fl = 3=2 (stars) and fl = 3=4(dust) Disks are truncated at R gal = 6R d , and bulges are truncated at the tidal radius R t = 10 2:2 r

Tittley, Eric

391

RESEARCH IN PARTICLE PHYSICS  

SciTech Connect (OSTI)

This is the final report for the Department of Energy Grant to Principal Investigators in Experimental and Theoretical Particle Physics at Boston University. The research performed was in the Energy Frontier at the LHC, the Intensity Frontier at Super-Kamiokande and T2K, the Cosmic Frontier and detector R&D in dark matter detector development, and in particle theory.

Kearns, Edward [Boston Universiy] [Boston Universiy

2013-07-12T23:59:59.000Z

392

Condensation Particle Counter  

E-Print Network [OSTI]

Model 3007 Condensation Particle Counter Operation and Service Manual 1930035, Revision C August 2002 P a r t i c l e I n s t r u m e n t s #12;#12;Model 3007 Condensation Particle Counter Operation............................................................................V 1. UNPACKING AND PARTS IDENTIFICATION..................................1 Unpacking the Condensation

Weber, Rodney

393

Pileup Per Particle Identification  

E-Print Network [OSTI]

We propose a new method for pileup mitigation by implementing "pileup per particle identification" (PUPPI). For each particle we first define a local shape $\\alpha$ which probes the collinear versus soft diffuse structure in the neighborhood of the particle. The former is indicative of particles originating from the hard scatter and the latter of particles originating from pileup interactions. The distribution of $\\alpha$ for charged pileup, assumed as a proxy for all pileup, is used on an event-by-event basis to calculate a weight for each particle. The weights describe the degree to which particles are pileup-like and are used to rescale their four-momenta, superseding the need for jet-based corrections. Furthermore, the algorithm flexibly allows combination with other, possibly experimental, probabilistic information associated with particles such as vertexing and timing performance. We demonstrate the algorithm improves over existing methods by looking at jet $p_T$ and jet mass. We also find an improvement on non-jet quantities like missing transverse energy.

Daniele Bertolini; Philip Harris; Matthew Low; Nhan Tran

2014-09-30T23:59:59.000Z

394

On the Crystallinity of Silicate Dust in the Interstellar Medium  

E-Print Network [OSTI]

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%.

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

2008-08-29T23:59:59.000Z

395

Imaging alpha particle detector  

DOE Patents [OSTI]

A method and apparatus for detecting and imaging alpha particles sources is described. A dielectric coated high voltage electrode and a tungsten wire grid constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source to be quantitatively or qualitatively analyzed. A thin polyester film window allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

Anderson, D.F.

1980-10-29T23:59:59.000Z

396

Imaging alpha particle detector  

DOE Patents [OSTI]

A method and apparatus for detecting and imaging alpha particles sources is described. A conducting coated high voltage electrode (1) and a tungsten wire grid (2) constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source (3) to be quantitatively or qualitatively analyzed. A thin polyester film window (4) allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

Anderson, David F. (Los Alamos, NM)

1985-01-01T23:59:59.000Z

397

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

E-Print Network [OSTI]

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.

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

398

Dust production 680-850 million years after the Big Bang  

E-Print Network [OSTI]

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.

Micha?owski, Micha? J

2015-01-01T23:59:59.000Z

399

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

E-Print Network [OSTI]

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.

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

400

A Synchrotron-Based Facility for the in-situ Location, Chemical and Mineralogical Characterization of ~10 um Particles Captured in Aerogel  

SciTech Connect (OSTI)

NASA's Stardust mission collected dust from the coma of Comet Wild-2 on January 2nd, 2004, by direct capture into aerogel cells that flew through the dust coma at 6 km/s. Stardust collected several hundred comet particles >10 {mu}m in size. These comet samples were delivered to Earth on January 15th, 2006. We developed a facility at the National Synchrotron Light Source at Brookhaven National Laboratory (Upton, NY, USA) for the in-situ characterization of 10 {mu}m particles collected in aerogel. These analytical instruments allow us to perform extensive chemical, mineralogical, and size-frequency characterization of particles captured in aerogel. These analyses are conducted without any invasive extraction, minimizing the possibility of contamination or particle loss during preparation. This facility was used to determine the chemical composition, the oxidation state, the mineralogy and to provide an indication of the grain size of the Wild-2 particles before they were removed from the aerogel. This information provides a catalog of particle types, allowing a more reasoned allocation of the particles to subsequent investigators based on a relatively detailed knowledge of the chemical composition and mineralogy of each particle. These measurements allowed a comparison of the chemical and mineralogical properties of the Wild-2 particles with other types of extraterrestrial materials, including interplanetary dust particles and meteorites. The success of in-situ analysis for Wild 2 particles demonstrates that synchrotron-based facilities will be important for the analysis of particles collected in aerogel on future earth-orbiting satellites and spacecraft.

Flynn, G.; Sutton, S; Lanzirotti, A

2009-01-01T23:59:59.000Z

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


401

Performance evaluation of PM?? and high-volume air samplers using a Coulter Counter Particle Size Analyzer  

E-Print Network [OSTI]

by the HiVol/Coulter process. The HiVol/Coulter process includes the determination of the percent of particles less than 10 um (AED) on a total suspended particulate matter filter. Representative particle size distributions were obtained for cotton dust... with an aerodynamic equivalent diameter (AED) larger than 10 micrometers (um) were seldom found in the air spaces of the lungs, Particles larger than 10 um (AED) do not pass the filtering mechanisms of the respiratory tract and are of less concern (AMA, 1963...

Herber, Douglas John

2012-06-07T23:59:59.000Z

402

PROPERTIES AND SPATIAL DISTRIBUTION OF DUST EMISSION IN THE CRAB NEBULA  

SciTech Connect (OSTI)

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.

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

403

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

SciTech Connect (OSTI)

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.

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

404

Cardiac Motion During Deep-Inspiration Breath-Hold: Implications for Breast Cancer Radiotherapy  

SciTech Connect (OSTI)

Purpose: Many patients with left-sided breast cancer receive adjuvant radiotherapy during deep-inspiration breath hold (DIBH) to minimize radiation exposure to the heart. We measured the displacement of the left anterior descending artery (LAD) and heart owing to cardiac motion during DIBH, relative to the standard tangential fields for left breast cancer radiotherapy. Methods and Materials: A total of 20 patients who had undergone computed tomography-based coronary angiography with retrospective electrocardiographic gating were randomly selected for the present study. The patients underwent scanning during DIBH to control the influence of respiration on cardiac motion. Standard medial and lateral tangential fields were placed, and the LADs were contoured on the systolic- and diastolic-phase computed tomography data sets by the clinicians. Displacement of the LAD during cardiac contractions was calculated in three directions: toward the posterior edge of the treatment fields, left-right, and anteroposterior. Displacement of the entire heart was measured on the maximal and minimal intensity projection computed tomography images. Results: The mean displacement of the LAD from cardiac contraction without the influence of respiration for 20 patients was 2.3 mm (range, 0.7-3.8) toward the posterior edge of the treatment fields, 2.6 mm (range, 1.0-6.8) in the left-right direction, and 2.3 mm (range, 0.6-6.5) in the anteroposterior direction. At least 30% of the LAD volume was displaced >5 mm in any direction in 2 patients (10%), and <10% of the LAD volume was displaced >5 mm in 10 patients (50%). The extent of displacement of the heart periphery during cardiac motion was negligible near the treatment fields. Conclusions: Displacement of the heart periphery near the treatment fields was negligible during DIBH; however, displacement of the LAD from cardiac contraction varied substantially between and within patients. We recommend maintaining {>=}5 mm of distance between the LAD and the field edge for patients undergoing breast cancer radiotherapy during DIBH.

Wang Xiaochun, E-mail: xiaochunw@mdanderson.org [Department of Radiation Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Pan Tinsu [Department of Imaging Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Pinnix, Chelsea [Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Zhang, Sean X.; Salehpour, Mohammad; Sun, Tzouh Liang [Department of Radiation Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Gladish, Gregory [Department of Diagnostic Radiology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Strom, Eric A.; Perkins, George H.; Tereffe, Welela; Woodward, Wendy; Hoffman, Karen E.; Buchholz, Thomas A.; Yu, T. Kuan [Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States)

2012-02-01T23:59:59.000Z

405

Interfractional Dose Variations in Intensity-Modulated Radiotherapy With Breath-Hold for Pancreatic Cancer  

SciTech Connect (OSTI)

Purpose: To investigate the interfractional dose variations for intensity-modulated radiotherapy (RT) combined with breath-hold (BH) at end-exhalation (EE) for pancreatic cancer. Methods and Materials: A total of 10 consecutive patients with pancreatic cancer were enrolled. Each patient was fixed in the supine position on an individualized vacuum pillow with both arms raised. Computed tomography (CT) scans were performed before RT, and three additional scans were performed during the course of chemoradiotherapy using a conventional RT technique. The CT data were acquired under EE-BH conditions (BH-CT) using a visual feedback technique. The intensity-modulated RT plan, which used five 15-MV coplanar ports, was designed on the initial BH-CT set with a prescription dose of 39 Gy at 2.6 Gy/fraction. After rigid image registration between the initial and subsequent BH-CT scans, the dose distributions were recalculated on the subsequent BH-CT images under the same conditions as in planning. Changes in the dose-volume metrics of the gross tumor volume (GTV), clinical target volume (CTV = GTV + 5 mm), stomach, and duodenum were evaluated. Results: For the GTV and clinical target volume (CTV), the 95th percentile of the interfractional variations in the maximal dose, mean dose, dose covering 95% volume of the region of structure, and percentage of the volume covered by the 90% isodose line were within {+-}3%. Although the volume covered by the 39 Gy isodose line for the stomach and duodenum did not exceed 0.1 mL at planning, the volume covered by the 39 Gy isodose line for these structures was up to 11.4 cm{sup 3} and 1.8 cm{sup 3}, respectively. Conclusions: Despite variations in the gastrointestinal state and abdominal wall position at EE, the GTV and CTV were mostly ensured at the planned dose, with the exception of 1 patient. Compared with the duodenum, large variations in the stomach volume receiving high-dose radiation were observed, which might be beyond the negligible range in achieving dose escalation with intensity-modulated RT combined with BH at EE.

Nakamura, Mitsuhiro [Department of Radiation Oncology and Image-Applied Therapy, Kyoto University Graduate School of Medicine, Kyoto (Japan); Shibuya, Keiko, E-mail: kei@kuhp.kyoto-u.ac.jp [Department of Radiation Oncology and Image-Applied Therapy, Kyoto University Graduate School of Medicine, Kyoto (Japan); Nakamura, Akira [Department of Radiation Oncology and Image-Applied Therapy, Kyoto University Graduate School of Medicine, Kyoto (Japan); Shiinoki, Takehiro [Department of Nuclear Engineering, Kyoto University Graduate School of Engineering, Kyoto (Japan); Matsuo, Yukinori [Department of Radiation Oncology and Image-Applied Therapy, Kyoto University Graduate School of Medicine, Kyoto (Japan); Nakata, Manabu [Clinical Radiology Service Division, Kyoto University Hospital, Kyoto (Japan); Sawada, Akira; Mizowaki, Takashi; Hiraoka, Masahiro [Department of Radiation Oncology and Image-Applied Therapy, Kyoto University Graduate School of Medicine, Kyoto (Japan)

2012-04-01T23:59:59.000Z

406

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

E-Print Network [OSTI]

Contemporary interstellar dust has never been analyzed in the laboratory, despite its obvious astronomical importance and its potential as a probe of stellar nucleosynthesis and galactic chemical evolution. Here we report the discovery of a novel fluorescent aerogel which is capable of capturing hypervelocity dust grains and passively recording their kinetic energies. An array of these "calorimetric" aerogel collectors in low earth orbit would lead to the capture and identification of large numbers of interstellar dust grains.

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

2003-03-27T23:59:59.000Z

407

A New Facility for Studying Shock Wave Passage over Dust Layers  

E-Print Network [OSTI]

A NEW FACILITY FOR STUDYING SHOCK WAVE PASSAGE OVER DUST LAYERS A Thesis by BRANDON DAVID MARKS Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... Brandon David Marks ii ABSTRACT To ensure safety regarding dust explosion hazards, it is important to study the dust lifting process experimentally and identify important parameters that will be valuable for development and validation...

Marks, Brandon

2013-05-30T23:59:59.000Z

408

Big Bang Day: 5 Particles - 5. The Next Particle  

ScienceCinema (OSTI)

Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 5. The Next Particle The "sparticle" - a super symmetric partner to all the known particles could be the answer to uniting all the known particles and their interactions under one grand theoretical pattern of activity. But how do researchers know where to look for such phenomena and how do they know if they find them? Simon Singh reviews the next particle that physicists would like to find if the current particle theories are to ring true.

None

2011-04-25T23:59:59.000Z

409

Research in particle theory  

SciTech Connect (OSTI)

In the test particle approximation, the scattering amplitude for two-particle scattering in (2+1)-dimensional Chern-Simons-Witten gravity and supergravity was computed and compared to the corresponding metric solutions. The formalism was then extended to the exact gauge theoretic treatment of the two-particle scattering problem and compared to 't Hooft's results from the metric approach. We have studied dynamical symmetry breaking in 2+1 dimensional field theories. We have analyzed strong Extended Technicolor (ETC) models where the ETC coupling is close to a critical value. There are effective scalar fields in each of the theories. We have worked our how such scalar particles can be produced and how they decay. The {phi}{sup 4} field theory was investigated in the Schrodinger representation. The critical behavior was extracted in an arbitrary number of dimensions in second order of a systematic truncation approximation. The correlation exponent agrees with known values within a few percent.

Mansouri, F.; Suranyi, P; Wijewardhana, L.C.R.

1991-10-01T23:59:59.000Z

410

Particle Physics Masterclass  

ScienceCinema (OSTI)

Students from six local high schools -- Farmingdale, Sachem East, Shoreham, Smithtown East, Ward Melville, and William Floyd -- came to Brookhaven National Laboratory to experience research with particle physicist Helio Takai. They were among more than 6,

Helio Takai

2010-01-08T23:59:59.000Z

411

Elementary particle theory  

SciTech Connect (OSTI)

The present state of the art in elementary particle theory is reviewed. Topics include quantum electrodynamics, weak interactions, electroweak unification, quantum chromodynamics, and grand unified theories. 113 references. (WHK)

Marciano, W.J.

1984-12-01T23:59:59.000Z

412

Particles in complex fluids   

E-Print Network [OSTI]

This thesis describes experimental studies of colloidal particles dispersed in solvents which themselves have phase transitions. One common definition of soft matter is: a material characterized by a mesoscopic length ...

Zand, Daniëlle D. van ’t

2010-01-01T23:59:59.000Z

413

Particle phenomenology and Maldacena  

E-Print Network [OSTI]

A brief review is offered of employing Maldacena's AdS/CFT correspondence in attempting to identify a model which extends to higher energy the standard model of particle phenomenology.

Paul H. Frampton

2008-04-18T23:59:59.000Z

414

GEOMETRIC CROSS SECTIONS OF DUST AGGREGATES AND A COMPRESSION MODEL FOR AGGREGATE COLLISIONS  

SciTech Connect (OSTI)

Geometric cross sections of dust aggregates determine their coupling with disk gas, which governs their motions in protoplanetary disks. Collisional outcomes also depend on geometric cross sections of initial aggregates. In a previous paper, we performed three-dimensional N-body simulations of sequential collisions of aggregates composed of a number of sub-micron-sized icy particles and examined radii of gyration (and bulk densities) of the obtained aggregates. We showed that collisional compression of aggregates is not efficient and that aggregates remain fluffy. In the present study, we examine geometric cross sections of the aggregates. Their cross sections decrease due to compression as well as to their gyration radii. It is found that a relation between the cross section and the gyration radius proposed by Okuzumi et al. is valid for the compressed aggregates. We also refine the compression model proposed in our previous paper. The refined model enables us to calculate the evolution of both gyration radii and cross sections of growing aggregates and reproduces well our numerical results of sequential aggregate collisions. The refined model can describe non-equal-mass collisions as well as equal-mass cases. Although we do not take into account oblique collisions in the present study, oblique collisions would further hinder compression of aggregates.

Suyama, Toru [Nagano City Museum, Hachimanpara Historical Park Ojimada-machi, Nagano 381-2212 (Japan); Wada, Koji [Planetary Exploration Research Center, Chiba Institute of Technology, Tsudanuma 2-17-1, Narashino, Chiba 275-0016 (Japan); Tanaka, Hidekazu [Institute of Low Temperature Science, Hokkaido University, N19-W8, Sapporo 060-0819 (Japan); Okuzumi, Satoshi, E-mail: museum@city.nagano.lg.jp [Department of Physics, Nagoya University, Nagoya, Aichi 464-8602 (Japan)

2012-07-10T23:59:59.000Z

415

ELEMENTARY PARTICLE INTERACTIONS  

SciTech Connect (OSTI)

The High-Energy Elementary Particle Interactions group at UT during the last three years worked on the following directions and projects: Collider-based Particle Physics; Neutrino Physics, particularly participation in “NO?A”, “Double Chooz”, and “KamLAND” neutrino experiments; and Theory, including Scattering amplitudes, Quark-gluon plasma; Holographic cosmology; Holographic superconductors; Charge density waves; Striped superconductors; and Holographic FFLO states.

EFREMENKO, YURI; HANDLER, THOMAS; KAMYSHKOV, YURI; SIOPSIS, GEORGE; SPANIER, STEFAN

2013-07-30T23:59:59.000Z

416

PARTICLES OF DIFFERENCE.  

SciTech Connect (OSTI)

It is no longer appropriate, if it ever was, to think of atmospheric aerosols as homogeneous spheres of uniform composition and size. Within the United States, and even more globally, not only the mass loading but also the composition, morphology, and size distribution of atmospheric aerosols are highly variable, as a function of location, and at a given location as a function of time. Particles of a given aerodynamic size may differ from one another, and even within individual particles material may be inhomogeneously distributed, as for example, carbon spherules imbedded in much larger sulfate particles. Some of the particulate matter is primary, that is, introduced into the atmosphere directly as particles, such as carbon particles in diesel exhaust. Some is secondary, that is, formed in the atmosphere by gas-to-particle conversion. Much of the material is inorganic, mainly sulfates and nitrates resulting mainly from energy-related emissions. Some of the material is carbonaceous, in part primary, in part secondary, and of this material some is anthropogenic and some biogenic. While the heterogeneity of atmospheric aerosols complicates the problem of understanding their loading and distribution, it may well be the key to its solution. By detailed examination of the materials comprising aerosols it is possible to infer the sources of these materials. It may be possible as well to identify specific health impairing agents. The heterogeneity of aerosol particles is thus the key to identifying their sources, to understanding the processes that govern their loading and properties, and to devising control strategies that are both effective and efficient. Future research must therefore take cognizance of differences among aerosol particles and use these differences to advantage.

SCHWARTZ,S.E.

2000-09-21T23:59:59.000Z

417

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

SciTech Connect (OSTI)

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.

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

418

E-Print Network 3.0 - asthma dust mite Sample Search Results  

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

cell Summary: -cockroach, anti-mouse, and anti-dust mite IgE levels, wheeze, cough, eczema and asthma. Results: Correlations... , maternal asthma, prenatal cockroach...

419

E-Print Network 3.0 - acute coal dust Sample Search Results  

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

(WTERT) Collection: Renewable Energy 25 Atmospheric Environment 38 (2004) 59916004 The air-borne particulate pollution in Beijing--concentration, Summary: ., 2002). Dust-soil,...

420

E-Print Network 3.0 - acute house dust Sample Search Results  

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

and Human Exposure Summary: rising worldwide (4). PBDEs accumulate in house dust, sewage sludge, biosolids, wildlifepets, and humans... matrices including furniture foam,...

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


421

COLD DUST BUT WARM GAS IN THE UNUSUAL ELLIPTICAL GALAXY NGC 4125  

SciTech Connect (OSTI)

Data from the Herschel Space Observatory have revealed an unusual elliptical galaxy, NGC 4125, which has strong and extended submillimeter emission from cold dust but only very strict upper limits to its CO and H I emission. Depending on the dust emissivity, the total dust mass is 2-5 × 10{sup 6} M {sub ?}. While the neutral gas-to-dust mass ratio is extremely low (<12-30), including the ionized gas traced by [C II] emission raises this limit to <39-100. The dust emission follows a similar r {sup 1/4} profile to the stellar light and the dust to stellar mass ratio is toward the high end of what is found in nearby elliptical galaxies. We suggest that NGC 4125 is currently in an unusual phase where evolved stars produced in a merger-triggered burst of star formation are pumping large amounts of gas and dust into the interstellar medium. In this scenario, the low neutral gas-to-dust mass ratio is explained by the gas being heated to temperatures ?10{sup 4} K faster than the dust is evaporated. If galaxies like NGC 4125, where the far-infrared emission does not trace neutral gas in the usual manner, are common at higher redshift, this could have significant implications for our understanding of high redshift galaxies and galaxy evolution.

Wilson, C. D.; Cridland, A.; Foyle, K.; Parkin, T. J.; Cooper, E. Mentuch [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada)] [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada); Roussel, H. [Institut d'Astrophysique de Paris, Université Pierre et Marie Curie, CNRS UMR 7095, F-75014 Paris (France)] [Institut d'Astrophysique de Paris, Université Pierre et Marie Curie, CNRS UMR 7095, F-75014 Paris (France); Sauvage, M.; Lebouteiller, V.; Madden, S. [Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot DAPNIA/Service d'Astrophysique, Bât. 709, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex (France)] [Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot DAPNIA/Service d'Astrophysique, Bât. 709, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex (France); Smith, M. W. L.; Gear, W. [School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA (United Kingdom)] [School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA (United Kingdom); Baes, M.; De Looze, I. [Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, B-9000 Gent (Belgium)] [Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, B-9000 Gent (Belgium); Bendo, G. [UK ALMA Regional Centre Node, Jodrell Bank Center for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom)] [UK ALMA Regional Centre Node, Jodrell Bank Center for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Boquien, M.; Boselli, A.; Ciesla, L. [Aix-Marseille Université, CNRS, LAM (Laboratoire d'Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France)] [Aix-Marseille Université, CNRS, LAM (Laboratoire d'Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom)] [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States)] [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Galametz, M. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)] [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); and others

2013-10-20T23:59:59.000Z

422

E-Print Network 3.0 - alkaline dust impact Sample Search Results  

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

Chem. Phys., 10, 39994012, 2010 www.atmos-chem-phys.net1039992010 Summary: in terms of accumulation of nitrate and sulfate, titration of dust alkalinity, and impact on...

423

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

E-Print Network [OSTI]

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...

Poole, Warren David

1975-01-01T23:59:59.000Z

424

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

E-Print Network [OSTI]

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

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

2002-04-07T23:59:59.000Z

425

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

SciTech Connect (OSTI)

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.

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

426

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...

427

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

E-Print Network [OSTI]

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

Ferrier, Ken

2009-01-01T23:59:59.000Z

428

E-Print Network 3.0 - american house dust Sample Search Results  

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

7 Evaluation of HVAC filters as a sampling mechanism for indoor microbial communities Summary: , in the dust samples collected in the unoccupied UTest House (mean value...

429

The roles of non-extensivity and dust concentration as bifurcation parameters in dust-ion acoustic traveling waves in magnetized dusty plasma  

SciTech Connect (OSTI)

Dust ion-acoustic traveling waves are studied in a magnetized dusty plasma in presence of static dust and non-extensive distributed electrons in the framework of Zakharov-Kuznesstov-Burgers (ZKB) equation. System of coupled nonlinear ordinary differential equations is derived from ZKB equation, and equilibrium points are obtained. Nonlinear wave phenomena are studied numerically using fourth order Runge-Kutta method. The change from unstable to stable solution and consequently to asymptotic stable of dust ion acoustic traveling waves is studied through dynamical system approach. It is found that some dramatical features emerge when the non-extensive parameter and the dust concentration parameters are varied. Behavior of the solution of the system changes from unstable to stable and stable to asymptotic stable depending on the value of the non-extensive parameter. It is also observed that when the dust concentration is increased the solution pattern is changed from oscillatory shocks to periodic solution. Thus, non-extensive and dust concentration parameters play crucial roles in determining the nature of the stability behavior of the system. Thus, the non-extensive parameter and the dust concentration parameters can be treated as bifurcation parameters.

Narayan Ghosh, Uday; Kumar Mandal, Pankaj, E-mail: pankajwbmsd@gmail.com; Chatterjee, Prasanta [Department of Mathematics, Siksha Bhavana Visva Bharati, Santiniketan, West Bengal 731235 (India)] [Department of Mathematics, Siksha Bhavana Visva Bharati, Santiniketan, West Bengal 731235 (India)

2014-03-15T23:59:59.000Z

430

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

SciTech Connect (OSTI)

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

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

2012-02-15T23:59:59.000Z

431

Single Particle Laser Ablation | EMSL  

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

Single Particle Laser Ablation Single Particle Laser Ablation Leads No leads are available at this time. Effect of Solar Radiation on the Optical Properties and Molecular...

432

A classification of spherically symmetric self-similar dust models  

E-Print Network [OSTI]

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

B. J. Carr

2000-03-02T23:59:59.000Z

433

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

SciTech Connect (OSTI)

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.

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

1990-01-01T23:59:59.000Z

434

Evaluation and recommendations for reduction of a silica dust exposure  

E-Print Network [OSTI]

to the increase in active tuberculosis among silicotics previously discussed. Perhaps there is a synergistic effect between silicosis and various lung cancers. A 1999 paper by Checkoway("6) showed a significantly (p=0. 02) increasing trend of lung cancer..., and that 100, 000 are exposed to silica dust through sandblasting, rock drilling and mining operations. &sI Silica is the second- most-common mineral in the earth's crust and a major component of sand, rock and mineral ores so it is not surprising to find...

Gruben, Raymond L

2000-01-01T23:59:59.000Z

435

Collapsing Inhomogeneous Dust Fluid in the Background of Dark Energy  

E-Print Network [OSTI]

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

Tanwi Bandyopadhyay; Subenoy Chakraborty

2006-05-11T23:59:59.000Z

436

Dust takes detour on ice-cloud journey | EMSL  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to UserProduct:Directives Templates8.Sifting Slush:NewDust takes detour on

437

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administrationcontroller systemsBiSite CulturalDepartment2)isomeraseUSCharge CompensationSpace Dust

438

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas ConchasPassiveSubmittedStatus Tom Fletcher,Future |Carlos ValenciaSpace Dust Analysis Could

439

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas ConchasPassiveSubmittedStatus Tom Fletcher,Future |Carlos ValenciaSpace Dust Analysis

440

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas ConchasPassiveSubmittedStatus Tom Fletcher,Future |Carlos ValenciaSpace Dust AnalysisSpace

Note: This page contains sample records for the topic "breathe dust particles" from the National Library of EnergyBeta (NLEBeta).
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to obtain the most current and comprehensive results.


441

INJECTION OF SUPERNOVA DUST IN NEARBY PROTOPLANETARY DISKS  

SciTech Connect (OSTI)

The early solar system contained a number of short-lived radionuclides (SLRs) such as {sup 26}Al with half-lives <15 Myr. The one-time presence of {sup 60}Fe strongly suggests that the source of these radionuclides was a nearby supernova. In this paper, we investigate the 'aerogel' model, which hypothesizes that the solar system's SLRs were injected directly into the solar system's protoplanetary disk from a supernova within the same star-forming region. Previous work has shown that disks generally survive the impact of supernova ejecta, but also that little gaseous ejecta can be injected into the disk. The aerogel model hypothesizes that radionuclides in the ejecta condensed into micron-sized dust grains that were injected directly into the solar nebula disk. Here, we discuss the density structure of supernova ejecta and the observational support for dust condensation in the ejecta. We argue that supernova ejecta are clumpy and describe a model to quantify this clumpiness. We also argue that infrared observations may be underestimating the fraction of material that condenses into dust. Building on calculations of how supernova ejecta interact with protoplanetary disks, we calculate the efficiency with which dust grains in the ejecta are injected into a disk. We find that about 70% of material in grains roughly 0.4 {mu}m in diameter can be injected into disks. If ejecta are clumpy, the solar nebula was struck by a clump with higher-than-average {sup 26}Al and {sup 60}Fe, and these elements condensed efficiently into large grains, then the abundances of SLRs in the early solar system can be explained, even if the disk lies 2 pc from the supernova explosion. The probability that all these factors are met is low, perhaps {approx}10{sup -3}-10{sup -2}, and receiving as much {sup 26}Al and {sup 60}Fe as the solar system did may be a rare event. Still, the aerogel model remains a viable explanation for the origins of the radionuclides in the early solar system, and may be the most plausible one.

Ouellette, N. [Department of Physics, Arizona State University, P.O. Box 871504, Tempe, AZ 85287-1504 (United States); Desch, S. J.; Hester, J. J. [School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, AZ 85287-1404 (United States)

2010-03-10T23:59:59.000Z

442

Diesel particles -a health hazard 1 Diesel particles  

E-Print Network [OSTI]

Diesel particles - a health hazard 1 Diesel particles - a health hazard #12;The Danish Ecological Council - August 20042 Diesel particles - a health hazard ISBN: 87-89843-61-4 Text by: Christian Ege 33150777 Fax no.: +45 33150971 E-mail: info@ecocouncil.dk www.ecocouncil.dk #12;Diesel particles - a health

443

Chemistry touches your life every day, from the air you breathe to the food you eat. The science of chemistry examines the atomic and  

E-Print Network [OSTI]

Chemistry Chemistry touches your life every day, from the air you breathe to the food you eat. The science of chemistry examines the atomic and molecular structure of matter and relates these structural medicine and biochemistry to plastics. The study of chemistry offers excellent undergraduate preparation

Miles, Will

444

Supertwistors and massive particles  

SciTech Connect (OSTI)

In the (super)twistor formulation of massless (super)particle mechanics, the mass-shell constraint is replaced by a “spin-shell” constraint from which the spin content can be read off. We extend this formalism to massive (super)particles (with N-extended space–time supersymmetry) in three and four space–time dimensions, explaining how the spin-shell constraints are related to spin, and we use it to prove equivalence of the massive N=1 and BPS-saturated N=2 superparticle actions. We also find the supertwistor form of the action for “spinning particles” with N-extended worldline supersymmetry, massless in four dimensions and massive in three dimensions, and we show how this simplifies special features of the N=2 case. -- Highlights: •Spin-shell constraints are related to Poincaré Casimirs. •Twistor form of 4D spinning particle for spin N/2. •Twistor proof of scalar/antisymmetric tensor equivalence for 4D spin 0. •Twistor form of 3D particle with arbitrary spin. •Proof of equivalence of N=1 and N=2 BPS massive 4D superparticles.

Mezincescu, Luca, E-mail: mezincescu@server.physics.miami.edu [Department of Physics, University of Miami, Coral Gables, FL 33124 (United States); Routh, Alasdair J., E-mail: a.j.routh@damtp.cam.ac.uk [DAMTP, CMS, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Townsend, Paul K., E-mail: p.k.townsend@damtp.cam.ac.uk [DAMTP, CMS, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)

2014-07-15T23:59:59.000Z

445

Big Bang Day: 5 Particles - 3. The Anti-particle  

ScienceCinema (OSTI)

Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 3. The Anti-particle. It appears to be the stuff of science fiction. Associated with every elementary particle is an antiparticle which has the same mass and opposite charge. Should the two meet and combine, the result is annihilation - and a flash of light. Thanks to mysterious processes that occurred after the Big Bang there are a vastly greater number of particles than anti-particles. So how could their elusive existence be proved? At CERN particle physicists are crashing together subatomic particles at incredibly high speeds to create antimatter, which they hope will finally reveal what happened at the precise moment of the Big Bang to create the repertoire of elementary particles and antiparticles in existence today.

None

2011-04-25T23:59:59.000Z

446

Big Bang Day: 5 Particles - 3. The Anti-particle  

SciTech Connect (OSTI)

Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 3. The Anti-particle. It appears to be the stuff of science fiction. Associated with every elementary particle is an antiparticle which has the same mass and opposite charge. Should the two meet and combine, the result is annihilation - and a flash of light. Thanks to mysterious processes that occurred after the Big Bang there are a vastly greater number of particles than anti-particles. So how could their elusive existence be proved? At CERN particle physicists are crashing together subatomic particles at incredibly high speeds to create antimatter, which they hope will finally reveal what happened at the precise moment of the Big Bang to create the repertoire of elementary particles and antiparticles in existence today.

None

2009-10-07T23:59:59.000Z

447

Size distribution and chemical composition of aerosol particles in the free troposphere over Japan: Aircraft measurements  

SciTech Connect (OSTI)

Aircraft measurements of number-, mass- and volume-size distributions of aerosols and concentration of sulfate, nitrate and others contained in particulate matter were made in the free troposphere over Japan in 1991-1994. Number-size distribution frequently shows a peak in the area of a diameter of D {ge} 1 {mu}m in the free troposphere during observational periods. A few peaks are identified in the volume-size distribution as estimated on the basis of number-size distribution having single