National Library of Energy BETA

Sample records for dust particles gas

  1. Hazards of explosives dusts: Particle size effects

    SciTech Connect (OSTI)

    Cashdollar, K L; Hertzberg, M; Green, G M

    1992-02-01

    At the request of the Department of Energy, the Bureau of Mines has investigated the hazards of military explosives dispersed as dust clouds in a 20-L test chamber. In this report, the effect of particle size for HMX, HNS, RDX, TATB, and TNT explosives dusts is studied in detail. The explosibility data for these dusts are also compared to those for pure fuel dusts. The data show that all of the sizes of the explosives dusts that were studied were capable of sustaining explosions as dust clouds dispersed in air. The finest sizes (<10 [mu]m) of explosives dusts were less reactive than the intermediate sizes (20 to 60 [mu]m); this is opposite to the particle size effect observed previously for the pure fuel dusts. At the largest sizes studied, the explosives dusts become somewhat less reactive as dispersed dust clouds. The six sizes of the HMX dust were also studied as dust clouds dispersed in nitrogen.

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

    E-Print Network [OSTI]

    Zadelhoff, Gerd-Jan van

    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

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

    E-Print Network [OSTI]

    Collett Jr., Jeffrey L.

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

  4. Bipolar charging of dust particles under ultraviolet radiation

    SciTech Connect (OSTI)

    Filippov, A. V. Babichev, V. N.; Fortov, V. E.; Gavrikov, A. V.; Pal', A. F.; Petrov, O. F.; Starostin, A. N.; Sarkarov, N. E.

    2011-05-15

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

  5. Particle creation in (2+1) circular dust collapse

    SciTech Connect (OSTI)

    Gutti, Sashideep; Singh, T. P.

    2007-09-15

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

  6. Color-based tracking of plasma dust particles

    SciTech Connect (OSTI)

    Villamayor, Michelle Marie S. Soriano, Maricor N.; Ramos, Henry J.; Kato, Shuichi; Wada, Motoi

    2014-02-15

    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.

  7. The dust and gas content of the Crab Nebula

    E-Print Network [OSTI]

    Owen, P J

    2015-01-01

    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...

  8. Nonstationary stochastic charge fluctuations of a dust particle in plasmas

    SciTech Connect (OSTI)

    Shotorban, B.

    2011-06-15

    Stochastic charge fluctuations of a dust particle that are due to discreteness of electrons and ions in plasmas can be described by a one-step process master equation [T. Matsoukas and M. Russell, J. Appl. Phys. 77, 4285 (1995)] with no exact solution. In the present work, using the system size expansion method of Van Kampen along with the linear noise approximation, a Fokker-Planck equation with an exact Gaussian solution is developed by expanding the master equation. The Gaussian solution has time-dependent mean and variance governed by two ordinary differential equations modeling the nonstationary process of dust particle charging. The model is tested via the comparison of its results to the results obtained by solving the master equation numerically. The electron and ion currents are calculated through the orbital motion limited theory. At various times of the nonstationary process of charging, the model results are in a very good agreement with the master equation results. The deviation is more significant when the standard deviation of the charge is comparable to the mean charge in magnitude.

  9. Ice Nuclei in Marine Air: Biogenic Particles or Dust?

    SciTech Connect (OSTI)

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

    2013-01-11

    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.

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

    E-Print Network [OSTI]

    Feng, Qian

    2011-10-21

    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...

  11. Evolution of Gas and Dust in Circumstellar Disks

    E-Print Network [OSTI]

    David W. Koerner

    1999-12-17

    A clear understanding of the chemical processing of matter, as it is transferred from a molecular cloud to a planetary system, depends heavily on knowledge of the physical conditions endured by gas and dust as these accrete onto a disk and are incorporated into planetary bodies. Reviewed here are astrophysical observations of circumstellar disks which trace their evolving properties. Accretion disks that are massive enough to produce a solar system like our own are typically larger than 100 AU. This suggests that the chemistry of a large fraction of the infalling material is not radically altered upon contact with a vigorous accretion shock. The mechanisms of accretion onto the star and eventual dispersal are not yet well understood, but timescales for the removal of gas and optically thick dust appear to be a few times 10$^6$ yrs. At later times, tenuous ``debris disks'' of dust remain around stars as old as a few times 10$^8$ yrs. Features in the morphology of the latter, such as inner holes, warps, and azimuthal asymmetries, are likely to be the result of the dynamical influence of large planetary bodies. Future observations will enlighten our understanding of chemical evolution and will focus on the search for disks in transition from a viscous accretion stage to one represented by a gas-free assemblage of colliding planetesimals. In the near future, comparative analysis of circumstellar dust and gas properties within a statistically significant sample of young stars at various ages will be possible with instrumentation such as SIRTF and SOFIA. Well-designed surveys will help place solar system analogs in a general context of a diversity of possible pathways for circumstellar evolution, one which encompasses the formation of stellar and brown-dwarf companions as well as planetary systems.

  12. Gas and dust in the star-forming region rho Oph A: The dust opacity exponent beta and the gas-to-dust mass ratio g2d

    E-Print Network [OSTI]

    Liseau, R; Lunttila, T; Olberg, M; Rydbeck, G; Bergman, P; Justtanont, K; Olofsson, G; de Vries, B L

    2015-01-01

    We aim at determining the spatial distribution of the gas and dust in star-forming regions and address their relative abundances in quantitative terms. We also examine the dust opacity exponent beta for spatial and/or temporal variations. Using mapping observations of the very dense rho Oph A core, we examined standard 1D and non-standard 3D methods to analyse data of far-infrared and submillimeter (submm) continuum radiation. The resulting dust surface density distribution can be compared to that of the gas. The latter was derived from the analysis of accompanying molecular line emission, observed with Herschel from space and with APEX from the ground. As a gas tracer we used N2H+, which is believed to be much less sensitive to freeze-out than CO and its isotopologues. Radiative transfer modelling of the N2H+(J=3-2) and (J=6-5) lines with their hyperfine structure explicitly taken into account provides solutions for the spatial distribution of the column density N(H2), hence the surface density distribution ...

  13. Expansion of a spherical dust gas -- the cosmological conundrum

    E-Print Network [OSTI]

    Müller, Ingo

    2015-01-01

    The universe is viewed as a dust gas filling a sphere and floating in infinite empty space. Einstein's gravitational equations are applied to this case together with appropriate boundary values. The equations are solved for initial conditions chosen so as to describe the observed Hubble diagram. We find that the solution is not unique so that more astronomical observations are needed. However, those solutions which were found do not exhibit an accelerated expansion of the universe, nor -- obviously then -- do they need the notion of a dark energy driving such an expansion. We present this study as an alternative to the prevailing Robertson-Walker cosmology.

  14. Effects of radiofrequency on dust particle dynamics in a plasma reactor

    SciTech Connect (OSTI)

    Horn, C.; Shotorban, B. [Department of Mechanical and Aerospace Engineering, University of Alabama in Huntsville, Huntsville, Alabama 35899 (United States); Davoudabadi, M. [ANSYS, Inc., Evanston, Illinois 60201 (United States)

    2011-12-01

    A numerical solution is obtained for the electron and ion number densities, and electric field of an rf argon plasma in a low pressure reactor utilizing a one-dimensional model. These variables are used to solve the equations describing the dynamical behavior of a dust particle under the influence of the electrical, gravity, and ion and neutral drag forces. The effects of the rf oscillations of the plasma on the dust particle are investigated through comparisons made between two sets of results. The first set is generated by a model in which the rf-period-averaged plasma variables are used in the dust particle equations while the second set is generated using the instantaneous plasma variables, without rf-period averaging. These two sets of results including the positions and charges of, and the various forces acting on the dust particles with different sizes and densities, are compared and significant differences are found.

  15. Simulation of the shielding of dust particles in low pressure glow Seung J. Choi and Mark J. Kushner

    E-Print Network [OSTI]

    Kushner, Mark

    Simulation of the shielding of dust particles in low pressure glow discharges Seung J. Choi) The dynamics of the shielding of particulates ("dust") in low pressure glow discharges have been investigated sections represented by the geometrical obscuration of the charged dust particles and their shield- ing

  16. Electrical time resolved metrology of dust particles growing in low pressure cold plasmas

    SciTech Connect (OSTI)

    Wattieaux, Gaeetan [PRISME, Orleans University, 12 rue de Blois BP 6744, 45067 Orleans cedex 2 (France); Mezeghrane, Abdelaziz [LPCQ, Mouloud Mammeri University, Tizi-Ouzou (Algeria); Boufendi, Laiefa [GREMI, Orleans University, 14 rue d'Issoudun BP 6744, 45067 Orleans cedex 2 (France)

    2011-09-15

    The electrical parameters of a capacitively coupled radiofrequency (CCRF) discharge change significantly when dust arises in the discharge. This work demonstrates the ability to follow in real time the evolution of the size and of the concentration of dust particles forming in a CCRF discharge from the variation of the electron density and of the self-bias voltage of the active electrode. According to experimental findings, it appears that the variation of this self-bias voltage depends on the surface of the dust particles. This trend is confirmed by an analytical modelling considering the low frequency behaviour of the phenomenon.

  17. Study of dust particle charging in weakly ionized inert gases taking into account the nonlocality of the electron energy distribution function

    SciTech Connect (OSTI)

    Filippov, A. V. Dyatko, N. A.; Kostenko, A. S.

    2014-11-15

    The charging of dust particles in weakly ionized inert gases at atmospheric pressure has been investigated. The conditions under which the gas is ionized by an external source, a beam of fast electrons, are considered. The electron energy distribution function in argon, krypton, and xenon has been calculated for three rates of gas ionization by fast electrons: 10{sup 13}, 10{sup 14}, and 10{sup 15} cm{sup ?1}. A model of dust particle charging with allowance for the nonlocal formation of the electron energy distribution function in the region of strong plasma quasi-neutrality violation around the dust particle is described. The nonlocality is taken into account in an approximation where the distribution function is a function of only the total electron energy. Comparative calculations of the dust particle charge with and without allowance for the nonlocality of the electron energy distribution function have been performed. Allowance for the nonlocality is shown to lead to a noticeable increase in the dust particle charge due to the influence of the group of hot electrons from the tail of the distribution function. It has been established that the screening constant virtually coincides with the smallest screening constant determined according to the asymptotic theory of screening with the electron transport and recombination coefficients in an unperturbed plasma.

  18. Ice formation on nitric acid coated dust particles: Laboratory and modeling studies

    SciTech Connect (OSTI)

    Kulkarni, Gourihar R.; Zhang, Kai; Zhao, Chun; Nandasiri, Manjula I.; Shutthanandan, V.; Liu, Xiaohong; Fast, Jerome D.; Berg, Larry K.

    2015-08-16

    Changes in the ice nucleation characteristics of atmospherically relevant mineral dust particles due to nitric acid coating are not well understood. Further, the atmospheric implications of dust coating on ice-cloud properties under different assumptions of primary ice nucleation mechanisms are unknown. We investigated ice nucleation ability of Arizona test dust, illite, K-feldspar and quartz as a function of temperature (-25 to -30°C) and relative humidity with respect to water (75 to 110%). Particles were size selected at 250 nm and transported (bare or coated) to the ice nucleation chamber to determine the fraction of particles nucleating ice at various temperature and water saturation conditions. All dust nucleated ice at water-subsaturated conditions, but the coated particles showed a reduction in their ice nucleation ability compared to bare particles. However, at water-supersaturated conditions, we observed that bare and coated particles had nearly similar ice nucleation characteristics. X-ray diffraction patterns indicated that structural properties of bare dust particles modified after acid treatment. We found that lattice parameters were slightly different, but crystallite sizes of the coated particles were reduced compared to bare particles. Next, single-column model results show that simulated ice crystal number concentrations mostly depends upon fraction of particles that are coated, primary ice nucleation mechanisms, and the competition between ice nucleation mechanisms to nucleate ice. In general, we observed that coating modify the ice-cloud properties and the picture of ice and mixed-phase cloud evolution is complex when different primary ice nucleation mechanisms are competing for fixed water vapor mass.

  19. Gas turbine engines with particle traps

    DOE Patents [OSTI]

    Boyd, Gary L. (Tempe, AZ); Sumner, D. Warren (Phoenix, AZ); Sheoran, Yogendra (Scottsdale, AZ); Judd, Z. Daniel (Phoenix, AZ)

    1992-01-01

    A gas turbine engine (10) incorporates a particle trap (46) that forms an entrapment region (73) in a plenum (24) which extends from within the combustor (18) to the inlet (32) of a radial-inflow turbine (52, 54). The engine (10) is thereby adapted to entrap particles that originate downstream from the compressor (14) and are otherwise propelled by combustion gas (22) into the turbine (52, 54). Carbonaceous particles that are dislodged from the inner wall (50) of the combustor (18) are incinerated within the entrapment region (73) during operation of the engine (10).

  20. DUST AND GAS IN THE MAGELLANIC CLOUDS FROM THE HERITAGE HERSCHEL KEY PROJECT. II. GAS-TO-DUST RATIO VARIATIONS ACROSS INTERSTELLAR MEDIUM PHASES

    SciTech Connect (OSTI)

    Roman-Duval, Julia; Gordon, Karl D.; Meixner, Margaret; Bot, Caroline; Bolatto, Alberto; Jameson, Katherine; Hughes, Annie; Hony, Sacha; Wong, Tony; Babler, Brian; Bernard, Jean-Philippe; Clayton, Geoffrey C.; Fukui, Yasuo; Galametz, Maud; Galliano, Frederic; Lebouteiller, Vianney; Lee, Min-Young; Israel, Frank; Li, Aigen; and others

    2014-12-20

    The spatial variations of the gas-to-dust ratio (GDR) provide constraints on the chemical evolution and lifecycle of dust in galaxies. We examine the relation between dust and gas at 10-50 pc resolution in the Large and Small Magellanic Clouds (LMC and SMC) based on Herschel far-infrared (FIR), H I 21 cm, CO, and H? observations. In the diffuse atomic interstellar medium (ISM), we derive the GDR as the slope of the dust-gas relation and find GDRs of 380{sub ?130}{sup +250} ± 3 in the LMC, and 1200{sub ?420}{sup +1600} ± 120 in the SMC, not including helium. The atomic-to-molecular transition is located at dust surface densities of 0.05 M {sub ?} pc{sup –2} in the LMC and 0.03 M {sub ?} pc{sup –2} in the SMC, corresponding to A {sub V} ? 0.4 and 0.2, respectively. We investigate the range of CO-to-H{sub 2} conversion factor to best account for all the molecular gas in the beam of the observations, and find upper limits on X {sub CO} to be 6 × 10{sup 20} cm{sup –2} K{sup –1} km{sup –1} s in the LMC (Z = 0.5 Z {sub ?}) at 15 pc resolution, and 4 × 10{sup 21} cm{sup –2} K{sup –1} km{sup –1} s in the SMC (Z = 0.2 Z {sub ?}) at 45 pc resolution. In the LMC, the slope of the dust-gas relation in the dense ISM is lower than in the diffuse ISM by a factor ?2, even after accounting for the effects of CO-dark H{sub 2} in the translucent envelopes of molecular clouds. Coagulation of dust grains and the subsequent dust emissivity increase in molecular clouds, and/or accretion of gas-phase metals onto dust grains, and the subsequent dust abundance (dust-to-gas ratio) increase in molecular clouds could explain the observations. In the SMC, variations in the dust-gas slope caused by coagulation or accretion are degenerate with the effects of CO-dark H{sub 2}. Within the expected 5-20 times Galactic X {sub CO} range, the dust-gas slope can be either constant or decrease by a factor of several across ISM phases. Further modeling and observations are required to break the degeneracy between dust grain coagulation, accretion, and CO-dark H{sub 2}. Our analysis demonstrates that obtaining robust ISM masses remains a non-trivial endeavor even in the local Universe using state-of-the-art maps of thermal dust emission.

  1. Ice Nucleation of Bare and Sulfuric Acid-coated Mineral Dust Particles and Implication for Cloud Properties

    SciTech Connect (OSTI)

    Kulkarni, Gourihar R.; Sanders, Cassandra N.; Zhang, Kai; Liu, Xiaohong; Zhao, Chun

    2014-08-27

    Ice nucleation properties of different dust species coated with soluble material are not well understood. We determined the ice nucleation ability of bare and sulfuric acid coated mineral dust particles as a function of temperature (-25 to -35 deg C) and relative humidity with respect to water (RHw). Five different mineral dust species: Arizona test dust (ATD), illite, montmorillonite, quartz and kaolinite were dry dispersed and size-selected at 150 nm and exposed to sulfuric acid vapors in the coating apparatus. The condensed sulfuric acid soluble mass fraction per particle was estimated from the cloud condensation nuclei activated fraction measurements. The fraction of dust particles nucleating ice at various temperatures and RHw was determined using a compact ice chamber. In water-subsaturated conditions, compared to bare dust particles, we found that only coated ATD particles showed suppression of ice nucleation ability while other four dust species did not showed the effect of coating on the fraction of particles nucleating ice. The results suggest that interactions between the dust surface and sulfuric acid vapor are important, such that interactions may or may not modify the surface via chemical reactions with sulfuric acid. At water-supersaturated conditions we did not observed the effect of coating, i.e. the bare and coated dust particles had similar ice nucleation behavior.

  2. Self-consistent three-dimensional model of dust particle transport and formation of Coulomb crystals in plasma processing reactors

    E-Print Network [OSTI]

    Kushner, Mark

    Self-consistent three-dimensional model of dust particle transport and formation of Coulomb, University of Illinois, Urbana, Illinois 61801 Gregory A. Hebnerb) Sandia National Laboratories, Albuquerque of Illinois, Urbana, Illinois 61801 Received 24 June 2002; accepted 30 August 2002 Dust particle transport

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

    SciTech Connect (OSTI)

    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)

    2014-07-15

    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.

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

    E-Print Network [OSTI]

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

    2013-06-11

    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.

  5. Gas mixtures for gas-filled particle detectors

    DOE Patents [OSTI]

    Christophorou, Loucas G. (Oak Ridge, TN); McCorkle, Dennis L. (Knoxville, TN); Maxey, David V. (Knoxville, TN); Carter, James G. (Oak Ridge, TN)

    1980-01-01

    Improved binary and tertiary gas mixtures for gas-filled particle detectors are provided. The components are chosen on the basis of the principle that the first component is one gas or mixture of two gases having a large electron scattering cross section at energies of about 0.5 eV and higher, and the second component is a gas (Ar) having a very small cross section at and below aout 0.5 eV, whereby fast electrons in the gaseous mixture are slowed into the energy range of about 0.5 eV where the cross section for the mixture is small and hence the electron mean free path is large. The reduction in both the cross section and the electron energy results in an increase in the drift velocity of the electrons in the gas mixtures over that for the separate components for a range of E/P (pressure-reduced electron field) values. Several gas mixtures are provided that provide faster response in gas-filled detectors for convenient E/P ranges as compared with conventional gas mixtures.

  6. Search for Phobos and Deimos gas/dust tori using in situ observations from Mars Global Surveyor MAG/ER

    E-Print Network [OSTI]

    California at Berkeley, University of

    outgassing or dust escape from the martian moons. Of the 1246 magnetic field perturbation events found causes than outgassing/dust escape from the martian moons. Thus we conclude that the amount of gas for outgassing or dust escape from the martian moons. Ó 2009 Elsevier Inc. All rights reserved. 1. Introduction

  7. Characterization of suspended flue gas particle systems with...

    Office of Scientific and Technical Information (OSTI)

    IMPACTORS; PERFORMANCE TESTING; FLUE GAS; PARTICLE SIZE; FLUIDIZED-BED COMBUSTION; AIR FILTERS; DISTRIBUTION; MEASURING INSTRUMENTS; SORTING; CHEMICAL REACTIONS; COMBUSTION;...

  8. N131: A dust bubble born from the disruption of a gas filament

    E-Print Network [OSTI]

    Zhang, Chuan-Peng; Wyrowski, Friedrich; Wang, Jun-Jie; Yuan, Jing-Hua; Xu, Jin-Long; Gong, Yan; Yeh, Cosmos C; Menten, Karl M

    2015-01-01

    OB type stars have strong ionizing radiation, and drive energetic winds. The ultraviolet (UV) radiation from ionizing stars may heat dust and ionize gas to sweep up an expanding bubble shell. This shell may be the result of feedback leading to a new generation of stars. N131 is an infrared dust bubble residing in a molecular filament. We study the formation and fragmentation of this bubble with multi-wavelength dust and gas observations. Towards the bubble N131, we analyzed archival multi-wavelength observations including 3.6, 4.5, 5.8, 8.0, 24, 70, 160, 250, 350, 500 \\mu m, 1.1 mm, and 21 cm. In addition, we performed new observations of CO (2-1), CO (1-0), and ^{13}CO (1-0) with the IRAM 30-m telescope. Multi-wavelength dust and gas observations reveal a ringlike shell with compact fragments, two filamentary structures, and a secondary bubble N131-A. The bubble N131 is a rare object with a large hole at 24 \\mu m and 21 cm in the direction of its center. The dust and gas clumps are compact and might have bee...

  9. Effect of particles attachment to multi-sized dust grains present in electrostatic sheaths of discharge plasmas

    SciTech Connect (OSTI)

    Zaham, B.; Tahraoui, A. Chekour, S.; Benlemdjaldi, D.

    2014-12-15

    The loss of electrons and ions due to their attachment to a Gauss-distributed sizes of dust grains present in electrostatic sheaths of discharge plasmas is investigated. A uni-dimensional, unmagnetized, and stationary multi-fluid model is proposed. Forces acting on the dust grain along with its charge are self-consistently calculated, within the limits of the orbit motion limited model. The dynamic analysis of dust grains shows that the contribution of the neutral drag force in the net force acting on the dust grain is negligible, whereas the contribution of the gravity force is found considerable only for micrometer particles. The dust grains trapping is only possible when the electrostatic force is balanced by the ion drag and the gravity forces. This trapping occurs for a limited radius interval of micrometer dust grains, which is around the most probable dust grain radius. The effect of electron temperature and ion density at the sheath edge is also discussed. It is shown that the attachment of particles reduces considerably the sheath thickness and induces dust grain deceleration. The increase of the lower limit as well as the upper limit of the dust radius reduces also the sheath thickness.

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

    SciTech Connect (OSTI)

    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)

    2013-03-15

    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.

  11. Method for removing undesired particles from gas streams

    DOE Patents [OSTI]

    Durham, Michael Dean (Castle Rock, CO); Schlager, Richard John (Aurora, CO); Ebner, Timothy George (Westminster, CO); Stewart, Robin Michele (Arvada, CO); Hyatt, David E. (Denver, CO); Bustard, Cynthia Jean (Littleton, CO); Sjostrom, Sharon (Denver, CO)

    1998-01-01

    The present invention discloses a process for removing undesired particles from a gas stream including the steps of contacting a composition containing an adhesive with the gas stream; collecting the undesired particles and adhesive on a collection surface to form an aggregate comprising the adhesive and undesired particles on the collection surface; and removing the agglomerate from the collection zone. The composition may then be atomized and injected into the gas stream. The composition may include a liquid that vaporizes in the gas stream. After the liquid vaporizes, adhesive particles are entrained in the gas stream. The process may be applied to electrostatic precipitators and filtration systems to improve undesired particle collection efficiency.

  12. It is well known that a rigid body impacting on a bed of fine particles or dust may resuspend some of this dust into

    E-Print Network [OSTI]

    Dalziel, Stuart

    an impacts on the bed. The interaction of the wake with the particles on the bed may lead to resuspension again at a different location. The traditional view is that the resuspension is the result. 1. INTRODUCTION Resuspension of dust and sediments is important in a wide variety of contexts

  13. Molecular gas and star formation towards the IR dust bubble S24 and its environs

    E-Print Network [OSTI]

    Cappa, C E; Firpo, V; Vasquez, J; López-Caraballo, C H; Rubio, M; Vazzano, M M

    2015-01-01

    We present a multi-wavelength analysis of the infrared dust bubble S24, and its environs, with the aim of investigating the characteristics of the molecular gas and the interstellar dust linked to them, and analyzing the evolutionary status of the young stellar objects (YSOs) identified there. Using APEX data, we mapped the molecular emission in the CO(2-1), $^{13}$CO(2-1), C$^{18}$O(2-1), and $^{13}$CO(3-2) lines in a region of about 5'x 5' in size around the bubble. The cold dust distribution was analyzed using ATLASGAL and Herschel images. Complementary IR and radio data were also used.The molecular gas linked to the S24 bubble, G341.220-0.213, and G341.217-0.237 has velocities between -48.0 km sec$^{-1}$ and -40.0 km sec$^{-1}$. The gas distribution reveals a shell-like molecular structure of $\\sim$0.8 pc in radius bordering the bubble. A cold dust counterpart of the shell is detected in the LABOCA and Herschel images.The presence of extended emission at 24 $\\mu$m and radio continuum emission inside the b...

  14. EFFECTS OF DUST FEEDBACK ON VORTICES IN PROTOPLANETARY DISKS

    SciTech Connect (OSTI)

    Fu, Wen; Liang, Edison; Li, Hui; Li, Shengtai; Lubow, Stephen

    2014-11-10

    We carried out two-dimensional, high-resolution simulations to study the effect of dust feedback on the evolution of vortices induced by massive planets in protoplanetary disks. Various initial dust to gas disk surface density ratios (0.001-0.01) and dust particle sizes (Stokes number 4 × 10{sup –4}-0.16) are considered. We found that while dust particles migrate inward, vortices are very effective at collecting them. When dust density becomes comparable to gas density within the vortex, a dynamical instability is excited and it alters the coherent vorticity pattern and destroys the vortex. This dust feedback effect is stronger with a higher initial dust/gas density ratio and larger dust grain. Consequently, we found that the disk vortex lifetime can be reduced up to a factor of 10. We discuss the implications of our findings on the survivability of vortices in protoplanetary disks and planet formation.

  15. Global estimates of mineral dust aerosol iron and aluminum solubility that account for particle size using diffusion-controlled and surface-area-controlled approximations

    E-Print Network [OSTI]

    2012-01-01

    T. D. Jickells (2006), Mineral particle size as a control onInvestigating Microbial-Mineral Interactions, CMS Workshopstudy of iron-containing mineral dust source materials, J.

  16. Integrating laboratory and field data to quantify the immersion freezing ice nucleation activity of mineral dust particles

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    DeMott, P. J.; Prenni, A. J.; McMeeking, G. R.; Sullivan, R. C.; Petters, M. D.; Tobo, Y.; Niemand, M.; Möhler, O.; Snider, J. R.; Wang, Z.; et al

    2014-06-27

    Data from both laboratory studies and atmospheric measurements are used to develop a simple parametric description for the immersion freezing activity of natural mineral dust particles. Measurements made with the Colorado State University (CSU) continuous flow diffusion chamber (CFDC) when processing mineral dust aerosols at a nominal 105% relative humidity with respect to water (RHw) are taken to approximate the immersion freezing nucleation activity of particles. Ice active frozen fractions vs. temperature for dusts representative of Saharan and Asian desert sources were consistent with similar measurements in atmospheric dust plumes for a limited set of comparisons available. The parameterization developedmore »follows the form of one suggested previously for atmospheric particles of non-specific composition in quantifying ice nucleating particle concentrations as functions of temperature and the total number concentration of particles larger than 0.5 ?m diameter. Such an approach does not explicitly account for surface area and time dependencies for ice nucleation, but sufficiently encapsulates the activation properties for potential use in regional and global modeling simulations, and possible application in developing remote sensing retrievals for ice nucleating particles. A correction factor is introduced to account for the apparent underestimate (by approximately 3, on average) of the immersion freezing fraction of mineral dust particles for CSU CFDC data processed at an RHw of 105% vs. maximum fractions active at higher RHw. Instrumental factors that affect activation behavior vs. RHw in CFDC instruments remain to be fully explored in future studies. Nevertheless, the use of this correction factor is supported by comparison to ice activation data obtained for the same aerosols from Aerosol Interactions and Dynamics of the Atmosphere (AIDA) expansion chamber cloud parcel experiments. Further comparison of the new parameterization to the immersion freezing surface active site density parameterization for mineral dust particles, developed separately from AIDA experimental data alone, shows excellent agreement for data collected in a descent through a Saharan aerosol layer. These studies support the utility of laboratory measurements to obtain atmospherically-relevant data on the ice nucleation properties of dust and other particle types, and suggest the suitability of considering all mineral dust as a single type of ice nucleating particle as a useful first order approximation in numerical modeling investigations.« less

  17. Integrating laboratory and field data to quantify the immersion freezing ice nucleation activity of mineral dust particles

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    DeMott, P. J.; Prenni, A. J.; McMeeking, G. R.; Sullivan, R. C.; Petters, M. D.; Tobo, Y.; Niemand, M.; Möhler, O.; Snider, J. R.; Wang, Z.; et al

    2015-01-13

    Data from both laboratory studies and atmospheric measurements are used to develop an empirical parameterization for the immersion freezing activity of natural mineral dust particles. Measurements made with the Colorado State University (CSU) continuous flow diffusion chamber (CFDC) when processing mineral dust aerosols at a nominal 105% relative humidity with respect to water (RHw) are taken as a measure of the immersion freezing nucleation activity of particles. Ice active frozen fractions vs. temperature for dusts representative of Saharan and Asian desert sources were consistent with similar measurements in atmospheric dust plumes for a limited set of comparisons available. The parameterizationmore »developed follows the form of one suggested previously for atmospheric particles of non-specific composition in quantifying ice nucleating particle concentrations as functions of temperature and the total number concentration of particles larger than 0.5 ?m diameter. Such an approach does not explicitly account for surface area and time dependencies for ice nucleation, but sufficiently encapsulates the activation properties for potential use in regional and global modeling simulations, and possible application in developing remote sensing retrievals for ice nucleating particles. A calibration factor is introduced to account for the apparent underestimate (by approximately 3, on average) of the immersion freezing fraction of mineral dust particles for CSU CFDC data processed at an RHw of 105% vs. maximum fractions active at higher RHw. Instrumental factors that affect activation behavior vs. RHw in CFDC instruments remain to be fully explored in future studies. Nevertheless, the use of this calibration factor is supported by comparison to ice activation data obtained for the same aerosols from Aerosol Interactions and Dynamics of the Atmosphere (AIDA) expansion chamber cloud parcel experiments. Further comparison of the new parameterization, including calibration correction, to predictions of the immersion freezing surface active site density parameterization for mineral dust particles, developed separately from AIDA experimental data alone, shows excellent agreement for data collected in a descent through a Saharan aerosol layer. These studies support the utility of laboratory measurements to obtain atmospherically relevant data on the ice nucleation properties of dust and other particle types, and suggest the suitability of considering all mineral dust as a single type of ice nucleating particle as a useful first-order approximation in numerical modeling investigations.« less

  18. TURBULENCE-INDUCED RELATIVE VELOCITY OF DUST PARTICLES. IV. THE COLLISION KERNEL

    SciTech Connect (OSTI)

    Pan, Liubin [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Padoan, Paolo, E-mail: lpan@cfa.harvard.edu, E-mail: ppadoan@icc.ub.edu [ICREA and Institut de Ciències del Cosmos, Universitat de Barcelona, IEEC-UB, Martí Franquès 1, E-08028 Barcelona (Spain)

    2014-12-20

    Motivated by its importance for modeling dust particle growth in protoplanetary disks, we study turbulence-induced collision statistics of inertial particles as a function of the particle friction time, ?{sub p}. We show that turbulent clustering significantly enhances the collision rate for particles of similar sizes with ?{sub p} corresponding to the inertial range of the flow. If the friction time, ?{sub p,} {sub h}, of the larger particle is in the inertial range, the collision kernel per unit cross section increases with increasing friction time, ?{sub p,} {sub l}, of the smaller particle and reaches the maximum at ?{sub p,} {sub l} = ?{sub p,} {sub h}, where the clustering effect peaks. This feature is not captured by the commonly used kernel formula, which neglects the effect of clustering. We argue that turbulent clustering helps alleviate the bouncing barrier problem for planetesimal formation. We also investigate the collision velocity statistics using a collision-rate weighting factor to account for higher collision frequency for particle pairs with larger relative velocity. For ?{sub p,} {sub h} in the inertial range, the rms relative velocity with collision-rate weighting is found to be invariant with ?{sub p,} {sub l} and scales with ?{sub p,} {sub h} roughly as ? ?{sub p,h}{sup 1/2}. The weighting factor favors collisions with larger relative velocity, and including it leads to more destructive and less sticking collisions. We compare two collision kernel formulations based on spherical and cylindrical geometries. The two formulations give consistent results for the collision rate and the collision-rate weighted statistics, except that the spherical formulation predicts more head-on collisions than the cylindrical formulation.

  19. Dust cluster explosion

    SciTech Connect (OSTI)

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

    2012-09-15

    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).

  20. DUST AND GAS IN THE MAGELLANIC CLOUDS FROM THE HERITAGE HERSCHEL KEY PROJECT. I. DUST PROPERTIES AND INSIGHTS INTO THE ORIGIN OF THE SUBMILLIMETER EXCESS EMISSION

    SciTech Connect (OSTI)

    Gordon, Karl D.; Roman-Duval, Julia; Meixner, Margaret; Bot, Caroline; Babler, Brian; Bernard, Jean-Philippe; Bolatto, Alberto; Jameson, Katherine; Boyer, Martha L.; Clayton, Geoffrey C.; Engelbracht, Charles; Fukui, Yasuo; Galametz, Maud; Galliano, Frederic; Hony, Sacha; Lebouteiller, Vianney; Indebetouw, Remy; Israel, Frank P.; Kawamura, Akiko; and others

    2014-12-20

    The dust properties in the Large and Small Magellanic clouds (LMC/SMC) are studied using the HERITAGE Herschel Key Project photometric data in five bands from 100 to 500 ?m. Three simple models of dust emission were fit to the observations: a single temperature blackbody modified by a power-law emissivity (SMBB), a single temperature blackbody modified by a broken power-law emissivity (BEMBB), and two blackbodies with different temperatures, both modified by the same power-law emissivity (TTMBB). Using these models, we investigate the origin of the submillimeter excess, defined as the submillimeter emission above that expected from SMBB models fit to observations <200 ?m. We find that the BEMBB model produces the lowest fit residuals with pixel-averaged 500 ?m submillimeter excesses of 27% and 43% for the LMC and SMC, respectively. Adopting gas masses from previous works, the gas-to-dust ratios calculated from our fitting results show that the TTMBB fits require significantly more dust than are available even if all the metals present in the interstellar medium (ISM) were condensed into dust. This indicates that the submillimeter excess is more likely to be due to emissivity variations than a second population of colder dust. We derive integrated dust masses of (7.3 ± 1.7) × 10{sup 5} and (8.3 ± 2.1) × 10{sup 4} M {sub ?} for the LMC and SMC, respectively. We find significant correlations between the submillimeter excess and other dust properties; further work is needed to determine the relative contributions of fitting noise and ISM physics to the correlations.

  1. Thermophoretic separation of aerosol particles from a sampled gas stream

    DOE Patents [OSTI]

    Postma, Arlin K. (Halfway, OR)

    1986-01-01

    A method for separating gaseous samples from a contained atmosphere that includes aerosol particles uses the step of repelling particles from a gas permeable surface or membrane by heating the surface to a temperature greater than that of the surrounding atmosphere. The resulting thermophoretic forces maintain the gas permeable surface clear of aerosol particles. The disclosed apparatus utilizes a downwardly facing heated plate of gas permeable material to combine thermophoretic repulsion and gravity forces to prevent particles of any size from contacting the separating plate surfaces.

  2. Method for removing undesired particles from gas streams

    DOE Patents [OSTI]

    Durham, M.D.; Schlager, R.J.; Ebner, T.G.; Stewart, R.M.; Hyatt, D.E.; Bustard, C.J.; Sjostrom, S.

    1998-11-10

    The present invention discloses a process for removing undesired particles from a gas stream including the steps of contacting a composition containing an adhesive with the gas stream; collecting the undesired particles and adhesive on a collection surface to form an aggregate comprising the adhesive and undesired particles on the collection surface; and removing the agglomerate from the collection zone. The composition may then be atomized and injected into the gas stream. The composition may include a liquid that vaporizes in the gas stream. After the liquid vaporizes, adhesive particles are entrained in the gas stream. The process may be applied to electrostatic precipitators and filtration systems to improve undesired particle collection efficiency. 11 figs.

  3. Transient beam losses in the LHC injection kickers from micron scale dust particles

    E-Print Network [OSTI]

    Goddard, B; Baer, T; Barnes, M J; Cerutti, F; Ferrari, A; Garrel, N; Gerardin, A; Guinchard, M; Lechner, A; Masi, A; Mertens, V; Morón Ballester, R; Redaelli, S; Uythoven, J; Vlachoudis, V; Zimmermann, F

    2012-01-01

    Transient beam losses on a time scale of a few ms have been observed in the LHC injection kickers, occurring mainly shortly after beam injection with a strong correlation in time to the kicker pulsing. The beam losses, which have at times affected LHC availability, are attributed to micron scale ceramic dust particles detached from the alumina beam pipe and accelerated into the beam. The beam related observations are described, together with laboratory measurements of beam pipe contamination and kicker vibration, simulations of electric field in the beam pipe and the basic dynamic model. Energy deposition simulations modelling the beam losses are presented and compared to measurement. Extrapolations to future LHC operation at higher intensities and energies are made, and prospects for mitigation are discussed.

  4. Gas insulated transmission line having tapered particle trapping ring

    DOE Patents [OSTI]

    Cookson, Alan H. (Pittsburgh, PA)

    1982-01-01

    A gas-insulated transmission line includes an outer sheath, an inner conductor, insulating supports and an insulating gas. A particle-trapping ring is secured to each insulating support, and it is comprised of a central portion and two tapered end portions. The ends of the particle trapping ring have a smaller diameter than the central portion of the ring, so as to enable the use of the particle trapping ring in a curved transmission line.

  5. Discharge source with gas curtain for protecting optics from particles

    DOE Patents [OSTI]

    Fornaciari, Neal R.; Kanouff, Michael P.

    2004-03-30

    A gas curtain device is employed to deflect debris that is generated by an extreme ultraviolet and soft x-ray radiation discharge source such as an electric discharge plasma source. The gas curtain device projects a stream of gas over the path of the radiation to deflect debris particles into a direction that is different from that of the path of the radiation. The gas curtain can be employed to prevent debris accumulation on the optics used in photolithography.

  6. 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]

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

    2013-01-01

    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...

  7. A HIGH TEMPERATURE GAS RECEIVER UTILIZING SMALL PARTICLES

    E-Print Network [OSTI]

    Hunt, Arlon

    2012-01-01

    of Energy under Arlon Hunt, "A New Solar Thermal Receiversolar thermal receiver that utilizes a dispersion of very small particles sus£e2ded in a gas to absorb the radiant energy

  8. Dust and gas in luminous proto-cluster galaxies at z=4.05: the case for different cosmic dust evolution in normal and starburst galaxies

    E-Print Network [OSTI]

    Tan, Q; Magdis, G; Pannella, M; Sargent, M; Riechers, D; Béthermin, M; Bournaud, F; Carilli, C; da Cunha, E; Dannerbauer, H; Dickinson, M; Elbaz, D; Gao, Y; Hodge, J; Owen, F; Walter, F

    2014-01-01

    We measure the dust and gas content of the three sub-millimeter galaxies (SMGs) in the GN20 proto-cluster at $z=4.05$ using new IRAM Plateau de Bure interferometer (PdBI) CO(4-3) and 1.2-3.3mm continuum observations. All these three SMGs are heavily dust obscured, with UV-based star formation rate (SFR) estimates significantly smaller than the ones derived from the bolometric IR, consistent with the spatial offsets revealed by HST and CO imaging. Based also on evaluations of the specific SFR, CO-to-H$_2$ conversion factor and gas depletion timescale, we classify all the three galaxies as starbursts (SBs), although with a lower confidence for GN20.2b that might be a later stage merging event. We place our measurements in the context of the evolutionary properties of main sequence (MS) and SB galaxies. ULIRGs have 3-5 times larger $L'_{\\rm CO}/M_{\\rm dust}$ and $M_{\\rm dust}/M_\\star$ ratios than $z=0$ MS galaxies, but by $z\\sim2$ the difference appears to be blurred, probably due to differential metallicity evo...

  9. Dust-to-Gas Ratios in Early-type Galaxies A. F. Crocker (University of Massachusetts Amherst), L. M. Young (New Mex-

    E-Print Network [OSTI]

    Bureau, Martin

    Dust-to-Gas Ratios in Early-type Galaxies A. F. Crocker (University of Massachusetts Amherst), L. M. Bureau, (University of Oxford, United Kingdom), Atlas3D Team We present dust-to-gas ratios for all mass. Cold gas masses are combined molecular and atomic masses, determined from single- dish CO

  10. Accepted Manuscript Dust in the planetary system: Dust interactions in space plasmas of the

    E-Print Network [OSTI]

    Aulanier, Guillaume

    Space Research Center, Polish Academy of Sciences, Warsaw, Poland Abstract Cosmic dust particles in cosmic dust particles. Some cosmic dust particles initially form by condensation of the heavy elements, colli- sional fragmentation, sputtering and particles are formed by agglomeration, condensation

  11. Dust Measurements in Tokamaks

    SciTech Connect (OSTI)

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

    2008-04-23

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

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

    SciTech Connect (OSTI)

    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)

    2013-01-15

    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.

  13. Characterization of secondary grain dust explosions 

    E-Print Network [OSTI]

    Schulman, Cheryl Wendler

    1983-01-01

    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...

  14. The Dust-Gas Fireball as a Special Form of the Electric Erosive Discharge Afterglow

    E-Print Network [OSTI]

    Emelin, S E; Vassiliev, N N

    2006-01-01

    Main results of researches of the electric erosive discharge afterglow plasma, of the fireballs being formed by this plasma and having some particular but deep similarities to the ball lightning are given. The analysis of our results and results of some other authors has allowed to specify the nature of radiation and stability of the shape for a dust-gas chemical fireball, to make series of assumptions concerning the mechanism of these properties. The experimental results and considerations of the given work can be interesting for physics of plasma with different kinds of condensed state, for an ascertainment of the chemiluminescence mechanism of the flame, as well as for a bead lightning understanding and for improvement of ball lightning laboratory analogues.

  15. Particle trap for compressed gas insulated transmission systems

    DOE Patents [OSTI]

    Cookson, Alan H. (Pittsburgh, PA)

    1985-01-01

    A particle trap is provided for gas insulated transmission lines having a central high voltage conductor supported within an outer coaxial conductive sheath by a dielectric support member. A cavity between the inner conductor and outer sheath is filled with a dielectric insulating gas. A cone-like particle deflector, mounted to the inner conductor, deflects moving particles away from the support member, to radially outer portions of the cavity. A conductive shield is disposed adjacent the outer sheath to form a field-free region in radially outer portions of the cavity, between the shield and the sheath. Particles traveling along the cavity are deflected by the cone-like deflector into the field-free region where they are held immobile. In a vertical embodiment, particles enter the field-free region through an upper end of a gap formed between shield and sheath members. In a horizontal embodiment, the deflector cone has a base which is terminated radially internally of the shield. Apertures in the shield located adjacent the deflector allow passage of deflected particles into the field-free region. The dielectric support member is thereby protected from contaminating particles that may otherwise come to rest thereon.

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

    E-Print Network [OSTI]

    McClure, Joshua Wayne

    2002-01-01

    properties of the particles. Another method uses the Coulter Multisizer, which measures the volume of each particle that has been collected on a filter. An equivalent diameter for each particle can be found by assuming the particle is spherical, which can...

  17. Sub-micrometer scale minor element mapping in interplanetary dust particles: a test for stratospheric contamination

    SciTech Connect (OSTI)

    Flynn, G.J.; Keller, L.P.; Sutton, S.R. (SUNYP); (NASA); (UC)

    2006-12-11

    We mapped the spatial distribution of minor elements including K, Mn, and Zn in 3 IDPs and found no evidence for the surface coatings (rims) of these elements that would be expected if the enrichments previously reported were due to contamination. Combined X-ray microprobe (XRM), energy dispersive x-ray fluorescence using a Transmission Electron Microscope (TEM), and electron microprobe measurements have determined that the average bulk chemical composition of the interplanetary dust particles (IDPs) collected from the Earth's stratosphere is enriched relative to the CI meteorite composition by a factor of 2 to 4 for carbon and for the moderately volatile elements Na, K, P, Mn, Cu, Zn, Ga, Ge, and Se, and enriched to {approx}30 times CI for Br. However, Jessberger et al., who have reported similar bulk enrichments using Proton Induced X-ray Emission (PIXE), attribute the enrichments to contamination by meteor-derived atmospheric aerosols during the several weeks these IDPs reside in the Earth's atmosphere prior to collection. Using scanning Auger spectroscopy, a very sensitive surface analysis technique, Mackinnon and Mogk have observed S contamination on the surface of IDPs, presumably due to the accretion of sulfate aerosols during stratospheric residence. But the S-rich layer they detected was so thin ({approx}100 angstroms thick) that the total amount of S on the surface was too small to significantly perturb the bulk S-content of a chondritic IDP. Stephan et al. provide support for the contamination hypothesis by reporting the enrichment of Br on the edges of the IDPs using Time-of-Flight Secondary-Ion Mass-Spectrometry (TOF-SIMS), but TOF-SIMS is notorious for producing false edge-effects, particularly on irregularly-shaped samples like IDPs. Sutton et al. mapped the spatial distribution of Fe, Ni, Zn, Br, and Sr, at the {approx}2 {micro}m scale, in four IDPs using element-specific x-ray fluorescence (XRF) computed microtomography. They found the moderately volatile elements Zn and Br, although spatially inhomogeneous, were not concentrated on the surface of any of the IDPs they examined, suggesting that the Zn and the Br enrichments in the IDPs are not due to contamination during stratospheric residence.

  18. The Relationship Between the Dust and Gas-Phase CO Across the California Molecular Cloud

    E-Print Network [OSTI]

    Kong, S; Lada, E A; Román-Zúñiga, C; Bieging, J H; Lombardi, M; Forbrich, J; Alves, J F

    2015-01-01

    A deep, wide-field, near-infrared imaging survey was used to construct an extinction map of the southeastern part of the California Molecular Cloud (CMC) with $\\sim$ 0.5 arc min resolution. The same region was also surveyed in the $^{12}$CO(2-1), $^{13}$CO(2-1), C$^{18}$O(2-1) emission lines at the same angular resolution. Strong spatial variations in the abundances of $^{13}$CO and C$^{18}$O were found to be correlated with variations in gas temperature, consistent with temperature dependent CO depletion/desorption on dust grains. The $^{13}$CO to C$^{18}$O abundance ratio was found to increase with decreasing extinction, suggesting selective photodissociation of C$^{18}$O by the ambient UV radiation field. The cloud averaged X-factor is found to be $$ $=$ 2.53 $\\times$ 10$^{20}$ ${\\rm cm}^{-2}~({\\rm K~km~s}^{-1})^{-1}$, somewhat higher than the Milky Way average. On sub-parsec scales we find no single empirical value of the X-factor that can characterize the molecular gas in cold (T$_{\\rm k}$ $\\lesssim$ 15 ...

  19. 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]

    Ledenyov, Oleg P

    2013-01-01

    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...

  20. Thermophoretic separation of aerosol particles from a sampled gas stream

    DOE Patents [OSTI]

    Postma, A.K.

    1984-09-07

    This disclosure relates to separation of aerosol particles from gas samples withdrawn from within a contained atmosphere, such as containment vessels for nuclear reactors or other process equipment where remote gaseous sampling is required. It is specifically directed to separation of dense aerosols including particles of any size and at high mass loadings and high corrosivity. The United States Government has rights in this invention pursuant to Contract DE-AC06-76FF02170 between the US Department of Energy and Westinghouse Electric Corporation.

  1. Transport coefficients of solid particles immersed in a viscous gas

    E-Print Network [OSTI]

    Vicente Garzó; William D. Fullmer; Christine M. Hrenya; Xiaolong Yin

    2015-11-12

    Transport properties of a suspension of solid particles in a viscous gas are studied. The dissipation in such systems arises from two sources: inelasticity in particle collisions and viscous dissipation due to the effect of the gas phase on the particles. Here, we consider a simplified case in which the mean relative velocity between the gas and solid phases is taken to be zero, such that "thermal drag" is the only remaining gas-solid interaction. Unlike the previous more general treatment of the drag force [Garz\\'o \\emph{et al.}, J. Fluid Mech. \\textbf{712}, 129 (2012)], here we take into account contributions to the (scaled) transport coefficients $\\eta^*$ (shear viscosity), $\\kappa^*$ (thermal conductivity) and $\\mu^*$ (Dufour-like coefficient) coming from the temperature-dependence of the (dimensionless) friction coefficient $\\gamma^*$ characterizing the amplitude of the drag force. At moderate densities, the thermal drag model (which is based on the Enskog kinetic equation) is solved by means of the Chapman-Enskog method and the Navier-Stokes transport coefficients are determined in terms of the coefficient of restitution, the solid volume fraction and the friction coefficient. The results indicate that the effect of the gas phase on $\\eta^*$ and $\\mu^*$ is non-negligible (especially in the case of relatively dilute systems) while the form of $\\kappa^*$ is the same as the one obtained in the dry granular limit. Finally, as an application of these results, a linear stability analysis of the hydrodynamic equations is carried out to analyze the conditions for stability of the homogeneous cooling state. A comparison with direct numerical simulations shows a good agreement for conditions of practical interest.

  2. 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]

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

    2013-02-18

    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.

  3. Long-Term Changes in Gas- and Particle-Phase Emissions from On...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Changes in Gas- and Particle-Phase Emissions from On-Road Diesel and Gasoline Vehicles Long-Term Changes in Gas- and Particle-Phase Emissions from On-Road Diesel and Gasoline...

  4. Hot Gas Filtration of Fine and Ultra fine Particles with Liquid...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Hot Gas Filtration of Fine and Ultra fine Particles with Liquid Phase Sintered SiC Ceramic DPF Hot Gas Filtration of Fine and Ultra fine Particles with Liquid Phase Sintered SiC...

  5. N-BODY SIMULATION OF PLANETESIMAL FORMATION THROUGH GRAVITATIONAL INSTABILITY OF A DUST LAYER IN LAMINAR GAS DISK

    SciTech Connect (OSTI)

    Michikoshi, Shugo; Kokubo, Eiichiro [Center for Computational Astrophysics, National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan); Inutsuka, Shu-ichiro, E-mail: michikoshi@cfca.j, E-mail: kokubo@th.nao.ac.j, E-mail: inutsuka@nagoya-u.j [Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602 (Japan)

    2010-08-20

    We investigate the formation process of planetesimals from the dust layer by the gravitational instability in the gas disk using local N-body simulations. The gas is modeled as a background laminar flow. We study the formation process of planetesimals and its dependence on the strength of the gas drag. Our simulation results show that the formation process is divided into three stages qualitatively: the formation of wake-like density structures, the creation of planetesimal seeds, and their collisional growth. The linear analysis of the dissipative gravitational instability shows that the dust layer is secularly unstable although Toomre's Q value is larger than unity. However, in the initial stage, the growth time of the gravitational instability is longer than that of the dust sedimentation and the decrease in the velocity dispersion. Thus, the velocity dispersion decreases and the disk shrinks vertically. As the velocity dispersion becomes sufficiently small, the gravitational instability finally becomes dominant. Then wake-like density structures are formed by the gravitational instability. These structures fragment into planetesimal seeds. The seeds grow rapidly owing to mutual collisions.

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

    E-Print Network [OSTI]

    2007-01-01

    Understanding the 30-year Barbados desert dust record. J.on mineral dust in the Barbados trade winds. Nature, 320,late 1960s to 1980s over Barbados (13°N, 60°W; Prospero and

  7. Method and apparatus for decreased undesired particle emissions in gas streams

    DOE Patents [OSTI]

    Durham, Michael Dean (Castle Rock, CO); Schlager, Richard John (Aurora, CO); Ebner, Timothy George (Westminster, CO); Stewart, Robin Michele (Arvada, CO); Bustard, Cynthia Jean (Littleton, CO)

    1999-01-01

    The present invention discloses a process for removing undesired particles from a gas stream including the steps of contacting a composition containing an adhesive with the gas stream; collecting the undesired particles and adhesive on a collection surface to form an aggregate comprising the adhesive and undesired particles on the collection surface; and removing the agglomerate from the collection zone. The composition may then be atomized and injected into the gas stream. The composition may include a liquid that vaporizes in the gas stream. After the liquid vaporizes, adhesive particles are entrained in the gas stream. The process may be applied to electrostatic precipitators and filtration systems to improve undesired particle collection efficiency.

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

    SciTech Connect (OSTI)

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

    2007-01-04

    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.

  9. Flue gas conditioning for improved particle collection in electrostatic precipitators

    SciTech Connect (OSTI)

    Durham, M.D.

    1992-10-14

    By injecting high concentrations of SO[sub 3] (80 to 100 ppM) it was possible to reduce the particle resistivity from 10[sup 11] to 10[sup 7] ohm-cm. However, it was very difficult to consistently obtain intermediate levels of resistivity. This was because of the steep relationships between gas phase SO[sub 3] and resistivity. It only takes a few ppM of SO[sub 3] to provide an order of magnitude change in resistivity. This is demonstrated by the curves in Figure 2. The water dew point for a gas stream with a moisture content of 10%, which is typical of coal fired boilers, is approximately 120[degrees]F. However, in a flue gas with only 2 ppM of SO[sub 3], sulfuric acid will begin to condense at 270[degrees]F. The effect of the rapid rise in acid dew point is reflected by the corresponding rapid decrease in resistivity. With no gas phase SO[sub 3] present the resistivity is in the high 10[sup 11] ohm-cm range. However with only 10 ppM of SO[sub 3], the resistivity drops three orders of magnitude. Therefore, intermediate levels of resistivity can only be obtained by controlling the SO[sub 3] concentration within 1 or 2 ppM.

  10. Silica aerogel for capturing intact interplanetary dust particles for the Tanpopo experiment

    E-Print Network [OSTI]

    Tabata, Makoto; Kawai, Hideyuki; Imai, Eiichi; Kawaguchi, Yuko; Hashimoto, Hirofumi; Yamagishi, Akihiko

    2015-01-01

    In this paper, we report the progress in developing a silica-aerogel-based cosmic dust capture panel for use in the Tanpopo experiment on the International Space Station (ISS). Previous studies revealed that ultralow-density silica aerogel tiles comprising two layers with densities of 0.01 and 0.03 g/cm$^3$ developed using our production technique were suitable for achieving the scientific objectives of the astrobiological mission. A special density configuration (i.e., box framing) aerogel with a holder was designed to construct the capture panels. Qualification tests for an engineering model of the capture panel as an instrument aboard the ISS were successful. Sixty box-framing aerogel tiles were manufactured in a contamination-controlled environment.

  11. Measures of galaxy dust and gas mass with Herschel photometry and prospects for ALMA

    E-Print Network [OSTI]

    Berta, S; Genzel, R; Foerster-Schreiber, N M; Tacconi, L J

    2015-01-01

    (Abridged) Combining the deepest Herschel extragalactic surveys (PEP, GOODS-H, HerMES), and Monte Carlo mock catalogs, we explore the robustness of dust mass estimates based on modeling of broad band spectral energy distributions (SEDs) with two popular approaches: Draine & Li (2007, DL07) and a modified black body (MBB). As long as the observed SED extends to at least 160-200 micron in the rest frame, M(dust) can be recovered with a >3 sigma significance and without the occurrence of systematics. An average offset of a factor ~1.5 exists between DL07- and MBB-based dust masses, based on consistent dust properties. At the depth of the deepest Herschel surveys (in the GOODS-S field) it is possible to retrieve dust masses with a S/N>=3 for galaxies on the main sequence of star formation (MS) down to M(stars)~1e10 [M(sun)] up to z~1. At higher redshift (z1, the delta(GDR) dependence on metallicity is consistent with the local relation. We combine far-IR Herschel data and sub-mm ALMA expected fluxes to study ...

  12. Evaluation of Electrostatic Particle Ionization and BioCurtain Technologies to Reduce Dust, Odor and other Pollutants from Broiler Houses Final Report 

    E-Print Network [OSTI]

    Jerez, S.; Muhktar, S.; Faulkner, W.; Casey, K.; Borhan, S.; Hoff, A.; VanDelist, B.

    2011-01-01

    geotextile fabric stretched over a quadrant-shaped, metal frame skeleton, and placed over the exhaust fans of the poultry houses. Air moving out of the house flows down along the top of the quadrant and particulate matter settles out on the ground. The air...-limited to no more than 2 mA to ensure worker and animal safety. The BioCurtain? technology for reducing dust and odor consists of a metal frame structure covered with a woven geotextile fabric and functions by settling airborne dust particles on the ground after...

  13. Improvement in understanding the deposition of ambient dust particles on ECAM (environmental continuous air monitor) filters, reduction of the alpha-particle interference of radon progeny and other radioactive aerosols in different particle size ranges on filters, and development of ECAMs with increased sensitivity under dusty outdoor conditions.

    SciTech Connect (OSTI)

    Schery, Stephen D., Wasiolek, Piotr; Rodgers, John

    1999-06-01

    Improvement in understanding the deposition of ambient dust particles on ECAM (environmental continuous air monitor) filters, reduction of the alpha-particle interference of radon progeny and other radioactive aerosols in different particle size ranges on filters, and development of ECAMs with increased sensitivity under dusty outdoor conditions.

  14. Transport of charged dust grains into the galactic halo

    E-Print Network [OSTI]

    Khoperskov, S A

    2014-01-01

    We develop a 3D dynamical model of dust outflows from galactic discs. The outflows are initiated by multiple SN explosions in a magnetized interstellar medium (ISM) with a gravitationally stratified density distribution. Dust grains are treated as particles in cells interacting collisionally with gas, and forced by stellar radiation of the disc and Lorenz force. We show that magnetic field plays a crucial role in accelerating the charged dust grains and expelling them out of the disc: in 10--20~Myr they can be elevated at distances up to 10~kpc above the galactic plane. The dust-to-gas ratio in the outflowing medium varies in the range $5 \\cdot 10^{-4} - 5 \\cdot 10^{-2}$ along the vertical stream. Overall the dust mass loss rate depends on the parameters of ISM and may reach up to $3\\times 10^{-2}$~\\Msun~yr$^{-1}$

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

    SciTech Connect (OSTI)

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

    2012-08-08

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

  16. LARGE DUST PARTICLES FROM COMETS. K. J. Meech, Institute for Astronomy, University of Hawaii, Honolulu HI, 96822, USA, meech@ifa.hawaii.edu, T. L. Farnham, Lowell Observatory, Flagstaff, AZ 86001, farnham@lowell.edu.

    E-Print Network [OSTI]

    Meech, Karen Jean

    LARGE DUST PARTICLES FROM COMETS. K. J. Meech, Institute for Astronomy, University of Hawaii, Honolulu HI, 96822, USA, meech@ifa.hawaii.edu, T. L. Farnham, Lowell Observatory, Flagstaff, AZ 86001

  17. Method and apparatus for decreased undesired particle emissions in gas streams

    DOE Patents [OSTI]

    Durham, M.D.; Schlager, R.J.; Ebner, T.G.; Stewart, R.M.; Bustard, C.J.

    1999-04-13

    The present invention discloses a process for removing undesired particles from a gas stream including the steps of contacting a composition containing an adhesive with the gas stream; collecting the undesired particles and adhesive on a collection surface to form an aggregate comprising the adhesive and undesired particles on the collection surface; and removing the agglomerate from the collection zone. The composition may then be atomized and injected into the gas stream. The composition may include a liquid that vaporizes in the gas stream. After the liquid vaporizes, adhesive particles are entrained in the gas stream. The process may be applied to electrostatic precipitators and filtration systems to improve undesired particle collection efficiency. 5 figs.

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

    E-Print Network [OSTI]

    2007-01-01

    Vegetation Changes, and Greenhouse Gas Warming M ASARU Yin the simulation. Greenhouse gas warming * The Nationalvegetation change, and greenhouse gas (GHG) warming using

  19. On-line gas chromatographic analysis of airborne particles

    DOE Patents [OSTI]

    Hering, Susanne V. (Berkeley, CA); Goldstein, Allen H. (Orinda, CA)

    2012-01-03

    A method and apparatus for the in-situ, chemical analysis of an aerosol. The method may include the steps of: collecting an aerosol; thermally desorbing the aerosol into a carrier gas to provide desorbed aerosol material; transporting the desorbed aerosol material onto the head of a gas chromatography column; analyzing the aerosol material using a gas chromatograph, and quantizing the aerosol material as it evolves from the gas chromatography column. The apparatus includes a collection and thermal desorption cell, a gas chromatograph including a gas chromatography column, heated transport lines coupling the cell and the column; and a quantization detector for aerosol material evolving from the gas chromatography column.

  20. Oil and Gas CDT What happens inside a frack? Particle-laden fluid transport in

    E-Print Network [OSTI]

    Henderson, Gideon

    Oil and Gas CDT What happens inside a frack? Particle-laden fluid transport in fracture networks, or fracking, for shale gas or other unconventional gas sources involves inducing and propagating fractures, and the productivity of the fracked well will be lower. However proppants can jam inside fractures preventing

  1. THE MECHANICAL DESIGN OF A GAS SUPPLY AND MIXING SYSTEM FOR THE AMS-02 PARTICLE DETECTOR

    E-Print Network [OSTI]

    Roma "La Sapienza", Università di

    the gas and monitors the gas content continuously (fig.2) [1]. Two storage vessels store the xenon1 THE MECHANICAL DESIGN OF A GAS SUPPLY AND MIXING SYSTEM FOR THE AMS-02 PARTICLE DETECTOR ONBOARD 100 scientists spread all over Europe, USA and far East. The TRD that is located above the Cryomagnet

  2. Trapping of dust and dust acoustic waves in laboratory plasmas

    SciTech Connect (OSTI)

    Prabhakara, H.R.; Tanna, V.L. [Institute for Plasma Research, Bhat, Gandhinagar 382 424 (India)] [Institute for Plasma Research, Bhat, Gandhinagar 382 424 (India)

    1996-08-01

    Trapping of negatively charged dust particles is observed in a hot cathode plasma discharge when a layer of dust is exposed to the plasma. The particles are visible in the scattered He{endash}Ne laser light. The trajectories of individual particles have been photographed. The dust particles are excluded from the sheath region of any object in the plasma. The intensity of scattered light as well as the potential on a floating Langmuir probe show coherent fluctuations in the frequency range 1{endash}15 Hz. After several hours of exposure to the plasma, the dust layer develops striations similar to those on sand dunes. Trapping of dust particles by the plasma and the possible identification of the observed low-frequency fluctuations with dust acoustic waves are discussed. {copyright} {ital 1996 American Institute of Physics.}

  3. TWO INTERSTELLAR DUST CANDIDATES FROM THE STARDUST AEROGEL INTERSTELLAR DUST

    E-Print Network [OSTI]

    Nittler, Larry R.

    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

  4. 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]

    Oleg P. Ledenyov; Ivan M. Neklyudov

    2013-06-14

    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.

  5. An integrated performance model for high temperature gas cooled reactor coated particle fuel

    E-Print Network [OSTI]

    Wang, Jing, 1976-

    2004-01-01

    The performance of coated fuel particles is essential for the development and deployment of High Temperature Gas Reactor (HTGR) systems for future power generation. Fuel performance modeling is indispensable for understanding ...

  6. Development of a High Temperature Gas-Cooled Reactor TRISO-coated particle fuel chemistry model

    E-Print Network [OSTI]

    Diecker, Jane T

    2005-01-01

    The first portion of this work is a comprehensive analysis of the chemical environment in a High Temperature Gas-Cooled Reactor TRISO fuel particle. Fission product inventory versus burnup is calculated. Based on those ...

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

    SciTech Connect (OSTI)

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

    2007-08-28

    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.

  8. Master equation for a quantum particle in a gas

    E-Print Network [OSTI]

    Klaus Hornberger

    2006-09-05

    The equation for the quantum motion of a Brownian particle in a gaseous environment is derived by means of S-matrix theory. This quantum version of the linear Boltzmann equation accounts non-perturbatively for the quantum effects of the scattering dynamics and describes decoherence and dissipation in a unified framework. As a completely positive master equation it incorporates both the known equation for an infinitely massive Brownian particle and the classical linear Boltzmann equation as limiting cases.

  9. Kinetics of Heterogeneous Ice Nucleation on the Surfaces of Mineral Dust Cores Inserted into Aqueous Ammonium Sulfate Particles

    E-Print Network [OSTI]

    Kinetics of Heterogeneous Ice Nucleation on the Surfaces of Mineral Dust Cores Inserted and absorb- ing terrestrial upwelling infrared radiation in the longwave.1 Unlike lower altitude clouds detailed know- ledge of both homogeneous and heterogeneous ice nucleation kinetics in the liquid phase.6

  10. Properties of potential eco-friendly gas replacements for particle detectors in high-energy physics

    E-Print Network [OSTI]

    Benussi, L; Piccolo, D; Saviano, G; Colafranceschi, S; Kjølbro, J; Sharma, A; Yang, D; Chen, G; Ban, Y; Li, Q

    2015-01-01

    Modern gas detectors for detection of particles require F-based gases for optimal performance. Recent regulations demand the use of environmentally unfriendly F-based gases to be limited or banned. This review studies properties of potential eco-friendly gas candidate replacements.

  11. Properties of potential eco-friendly gas replacements for particle detectors in high-energy physics

    E-Print Network [OSTI]

    Benussi, L; Piccolo, D; Saviano, G; Colafranceschi, S; Kjølbro, J; Yang, D; Chen, G; Ban, Y; Li, Q; Sharma, A

    2015-01-01

    Modern gas detectors for detection of particles require F-based gases for op- timal performance. Recent regulations demand the use of environmentally un- friendly Freon-based gases to be limited or banned. This review studies properties of potential eco-friendly gas candidate replacements.

  12. Gas-liquid transition in the model of particles interacting at high energy

    E-Print Network [OSTI]

    S. Bondarenko; K. Komoshvili

    2013-10-07

    An application of the ideas of the inertial confinement fusion process in the case of particles interacting at high energy is investigated. A possibility of the gas-liquid transition in the gas is considered using different approaches. In particular, a shock wave description of interactions between particles is studied and a self-similar solution of Euler's equation is discussed. Additionally, Boltzmann equation is solved for self-consistent field (Vlasov's equation) in linear approximation for the case of a gas under external pressure and the corresponding change of Knudsen number of the system is calculated.

  13. Vertically aligned gas-insulated transmission line having particle traps at the inner conductor

    DOE Patents [OSTI]

    Dale, Steinar J. (Monroeville, PA)

    1984-01-01

    Gas insulated electrical apparatus having first and second conductors separated by an insulating support within an insulating gas environment, and particle traps disposed along the surface of the high potential conductor for trapping and inactivating foreign particles which may be present within the insulating gas medium. Several embodiments of the invention were developed which are particularly suited for vertically aligned gas insulated transmission lines. The particle traps are grooves or cavities formed into the walls of the tubular inner conductor, without extending into the hollow portion of the conductor. In other embodiments, the traps are appendages or insert flanges extending from the inner conductor, with the insulator supports contacting the appendages instead of the inner conductor.

  14. Means and method for the destruction of particles entrained in a gas stream

    DOE Patents [OSTI]

    Botts, Thomas E. (Wading River, NY); Powell, James R. (Shoreham, NY)

    1980-01-01

    An apparatus and method for the destruction of particles entrained in a gas stream are disclosed. Destruction in the context of the subject invention means the fragmentation and/or vaporization of particles above a certain size limit. The subject invention contemplates destroying such particles by exposing them to intense bursts of laser light, such light having a frequency approximately equal to or less than the mean size of such particles. This invention is particularly adopted to the protection of turbine blades in open cycle coal-fired turbine systems. Means for introducing various chemical species and activating them by exposure to laser light are also disclosed.

  15. Particle simulation of vibrated gas-fluidized beds of cohesive fine powders

    E-Print Network [OSTI]

    Sung Joon Moon; I. G. Kevrekidis; S. Sundaresan

    2006-08-09

    We use three-dimensional particle dynamics simulations, coupled with volume-averaged gas phase hydrodynamics, to study vertically vibrated gas-fluidized beds of fine, cohesive powders. The volume-averaged interstitial gas flow is restricted to be one-dimensional (1D). This simplified model captures the spontaneous development of 1D traveling waves, which corresponds to bubble formation in real fluidized beds. We use this model to probe the manner in which vibration and gas flow combine to influence the dynamics of cohesive particles. We find that as the gas flow rate increases, cyclic pressure pulsation produced by vibration becomes more and more significant than direct impact, and in a fully fluidized bed this pulsation is virtually the only relevant mechanism. We demonstrate that vibration assists fluidization by creating large tensile stresses during transient periods, which helps break up the cohesive assembly into agglomerates.

  16. Feasibility of an alpha particle gas densimeter for stack sampling applications 

    E-Print Network [OSTI]

    Johnson, Randall Mark

    1983-01-01

    , for conceivable ranges of flue gas composition, the maximum error in density due to the uncertainty in gas composition is less than 2%. ACKNOWLEDGEMENTS I wish to express my appreciation to Dr. R. A. Fjeld and Dr. A. R. McFarland for their patience... LISTING APPENDIX C TABULATED RESULTS 58 60 72 VI TA 84 Vi LIST OF TABLES TABLE P age I Typical Flue Gas Compositions II Model Flue Gas Compositions 35 Coeff icients for Alpha particle Stopping Power Functions 59 Computed and Experimental...

  17. Investigation of Gas Solid Fluidized Bed Dynamics with Non-Spherical Particles

    SciTech Connect (OSTI)

    Choudhuri, Ahsan

    2013-06-30

    One of the largest challenges for 21st century is to fulfill global energy demand while also reducing detrimental impacts of energy generation and use on the environment. Gasification is a promising technology to meet the requirement of reduced emissions without compromising performance. Coal gasification is not an incinerating process; rather than burning coal completely a partial combustion takes place in the presence of steam and limited amounts of oxygen. In this controlled environment, a chemical reaction takes place to produce a mixture of clean synthetic gas. Gas-solid fluidized bed is one such type of gasification technology. During gasification, the mixing behavior of solid (coal) and gas and their flow patterns can be very complicated to understand. Many attempts have taken place in laboratory scale to understand bed hydrodynamics with spherical particles though in actual applications with coal, the particles are non-spherical. This issue drove the documented attempt presented here to investigate fluidized bed behavior using different ranges of non-spherical particles, as well as spherical. For this investigation, various parameters are controlled that included particle size, bed height, bed diameter and particle shape. Particles ranged from 355 µm to 1180 µm, bed diameter varied from 2 cm to 7 cm, two fluidized beds with diameters of 3.4 cm and 12.4 cm, for the spherical and non-spherical shaped particles that were taken into consideration. Pressure drop was measured with increasing superficial gas velocity. The velocity required in order to start to fluidize the particle is called the minimum fluidization velocity, which is one of the most important parameters to design and optimize within a gas-solid fluidized bed. This minimum fluidization velocity was monitored during investigation while observing variables factors and their effect on this velocity. From our investigation, it has been found that minimum fluidization velocity is independent of bed height for both spherical and non-spherical particles. Further, it decrease with decreasing particle size and decreases with decreasing bed diameter. Shadow sizing, a non-intrusive imaging and diagnostic technology, was also used to visualize flow fields inside fluidized beds for both spherical and non- spherical particles and to detect the particle sizes.

  18. Combined Analysis of Two- and Three-Particle Correlations in q,p-Bose Gas Model

    E-Print Network [OSTI]

    Alexandre M. Gavrilik

    2006-11-07

    q-deformed oscillators and the q-Bose gas model enable effective description of the observed non-Bose type behavior of the intercept ("strength") $\\lambda^{(2)}\\equiv C^{(2)}(K,K)-1$ of two-particle correlation function $C^{(2)}(p_1,p_2)$ of identical pions produced in heavy-ion collisions. Three- and n-particle correlation functions of pions (or kaons) encode more information on the nature of the emitting sources in such experiments. And so, the q-Bose gas model was further developed: the intercepts of n-th order correlators of q-bosons and the n-particle correlation intercepts within the q,p-Bose gas model have been obtained, the result useful for quantum optics, too. Here we present the combined analysis of two- and three-pion correlation intercepts for the q-Bose gas model and its q,p-extension, and confront with empirical data (from CERN SPS and STAR/RHIC) on pion correlations. Similar to explicit dependence of $\\lambda^{(2)}$ on mean momenta of particles (pions, kaons) found earlier, here we explore the peculiar behavior, versus mean momentum, of the 3-particle correlation intercept $\\lambda^{(3)}(K)$. The whole approach implies complete chaoticity of sources, unlike other joint descriptions of two- and three-pion correlations using two phenomenological parameters (e.g., core-halo fraction plus partial coherence of sources).

  19. Hydrostatic Simulation of Earth's Atmospheric Gas Using Multi-particle Collision Dynamics

    E-Print Network [OSTI]

    Pattisahusiwa, Asis; Virid, Sparisoma

    2015-01-01

    Multi-particle collision dynamics (MPCD) is a mesoscopic simulation method to simulate fluid particle-like flows. MPCD has been widely used to simulate various problems in condensed matter. In this study, hydrostatic behavior of gas in the Earth's atmospheric layer is simulated by using MPCD method. The simulation is carried out by assuming the system under ideal state and is affected only by gravitational force. Gas particles are homogeneous and placed in 2D box. Interaction of the particles with the box is applied through implementation of boundary conditions (BC). Periodic BC is applied on the left and the right side, specular reflection on the top side, while bounce-back on the bottom side. Simulation program is executed in Arch Linux and running in notebook with processor Intel i5 @2700 MHz with 10 GB DDR3 RAM. The results show behaviors of the particles obey kinetic theory for ideal gas when gravitational acceleration value is proportional to the particle mass. Density distribution as a function of alti...

  20. Particle trap with dielectric barrier for use in gas insulated transmission lines

    DOE Patents [OSTI]

    Dale, S.J.

    1982-06-15

    A gas-insulated transmission line includes an outer sheath, an inner conductor within the outer sheath, insulating supports supporting the inner conductor within the outer sheath, and an insulating gas electrically insulating the inner conductor from the outer sheath. An apertured particle trapping electrode is disposed within the outer sheath, and the electrode has a pair of dielectric members secured at each longitudinal end thereof, with the dielectric members extending outwardly from the apertured electrode. 7 figs.

  1. Particle trap with dielectric barrier for use in gas insulated transmission lines

    DOE Patents [OSTI]

    Dale, Steinar J. (Monroeville, PA)

    1982-01-01

    A gas-insulated transmission line includes an outer sheath, an inner conductor within the outer sheath, insulating supports supporting the inner conductor within the outer sheath, and an insulating gas electrically insulating the inner conductor from the outer sheath. An apertured particle trapping electrode is disposed within the outer sheath, and the electrode has a pair of dielectric members secured at each longitudinal end thereof, with the dielectric members extending outwardly from the apertured electrode.

  2. Closures for Course-Grid Simulation of Fluidized Gas-Particle Flows

    SciTech Connect (OSTI)

    Sankaran Sundaresan

    2010-02-14

    Gas-particle flows in fluidized beds and riser reactors are inherently unstable, and they manifest fluctuations over a wide range of length and time scales. Two-fluid models for such flows reveal unstable modes whose length scale is as small as ten particle diameters. Yet, because of limited computational resources, gas-particle flows in large fluidized beds are invariably simulated by solving discretized versions of the two-fluid model equations over a coarse spatial grid. Such coarse-grid simulations do not resolve the small-scale spatial structures which are known to affect the macroscale flow structures both qualitatively and quantitatively. Thus there is a need to develop filtered two-fluid models which are suitable for coarse-grid simulations and capturing the effect of the small-scale structures through closures in terms of the filtered variables. The overall objective of the project is to develop validated closures for filtered two-fluid models for gas-particle flows, with the transport gasifier as a primary, motivating example. In this project, highly resolved three-dimensional simulations of a kinetic theory based two-fluid model for gas-particle flows have been performed and the statistical information on structures in the 100-1000 particle diameters length scale has been extracted. Based on these results, closures for filtered two-fluid models have been constructed. The filtered model equations and closures have been validated against experimental data and the results obtained in highly resolved simulations of gas-particle flows. The proposed project enables more accurate simulations of not only the transport gasifier, but also many other non-reacting and reacting gas-particle flows in a variety of chemical reactors. The results of this study are in the form of closures which can readily be incorporated into existing multi-phase flow codes such as MFIX (www.mfix.org). Therefore, the benefits of this study can be realized quickly. The training provided by this project has prepared a PhD student to enter research and development careers in DOE laboratories or chemicals/energy-related industries.

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

    SciTech Connect (OSTI)

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

    2010-07-16

    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.

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

    E-Print Network [OSTI]

    Gorti, Uma; Dullemond, Cornelis

    2015-01-01

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

  5. Gas flow driven by thermal creep in dusty plasma T. M. Flanagan and J. Goree

    E-Print Network [OSTI]

    Goree, John

    Gas flow driven by thermal creep in dusty plasma T. M. Flanagan and J. Goree Department of Physics 2009 Thermal creep flow TCF is a flow of gas driven by a temperature gradient along a solid boundary to the bulk gas, causing the bulk gas to flow, thereby stirring the suspension of dust particles. This result

  6. Particle trap to sheath contact for a gas-insulated transmission line having a corrugated outer conductor

    DOE Patents [OSTI]

    Fischer, William H. (Pittsburgh, PA); Cookson, Alan H. (Pittsburgh, PA); Yoon, Kue H. (Pittsburgh, PA)

    1984-04-10

    A particle trap to outer elongated conductor or sheath contact for gas-insulated transmission lines. The particle trap to outer sheath contact of the invention is applicable to gas-insulated transmission lines having either corrugated or non-corrugated outer sheaths. The contact of the invention includes an electrical contact disposed on a lever arm which in turn is rotatably disposed on the particle trap and biased in a direction to maintain contact between the electrical contact and the outer sheath.

  7. Evaluation of an Electrostatic Dust Removal System with Potential...

    Office of Scientific and Technical Information (OSTI)

    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...

  8. The Sky in Dust -- Methods and Prospects of Dust Astronomy

    E-Print Network [OSTI]

    M. Landgraf; E. Grün; R. Srama; S. Helfert; S. Kempf; G. Morgas-Klostermeyer; M. Rachev; A. Srowig; S. Auer; M. Horànyi; Z. Sternovsky; D. Harris

    2006-02-05

    Information about the make-up of the galaxy arrives in the Solar system in many forms: photons of different energies, classically collected by ground- and space-based telescopes, neutral and charged atomic particles, and solid macroscopic particles: cosmic dust particles. Dust particles, like photons, carry information from remote sites in space and time. This information can be analysed in order to understand the processes and mechanisms that are involved in the formation and evolution of solid matter in the galaxy. This approach is called ``Dust Astronomy'' which is carried out by means of a dust telescope on a dust observatory in space. The analysis of cosmic grains collected in the high atmosphere of the Earth has shown that each dust grain is a small world with various sub-grains featuring different galactic origin and evolution, which is identified on the basis of elementary and isotopic analysis. Independent information about the origin and evolution of the grains coming from the kinematic properties of the arrival trajectory would be invaluable for linking the isotopic signature of the formation of heavy elements in old stars and supernovae to distinctive regions in our galaxy, e.g. known star-forming regions. Here we present a skymap of potential dust sources together with a report on already existing lab hardware of a trajectory sensor and a large-area mass spectrometre.

  9. Gas accumulation in particle-rich suspensions and implications for bubble populations in crystal-rich magma

    E-Print Network [OSTI]

    Rempel, Alan W.

    Gas accumulation in particle-rich suspensions and implications for bubble populations in crystal Stromboli degassing Gas mobility plays an important role in driving volcanic eruptions and controlling eruption style. The explosivity of an eruption depends, among other factors, on how easily gas can escape

  10. Global morphology and physical relations between the stars, gas and dust in the disc and arms of M100

    E-Print Network [OSTI]

    J. H. Knapen; J. E. Beckman

    1996-07-04

    We study star formation processes in the disc of the weakly barred grand design spiral galaxy M100 (NGC 4321) from a variety of images tracing recent massive star formation, old and young stars, dust, and neutral hydrogen. Differences between arm and interarm regions are specifically studied by decomposing the images into arm and non-arm zones. We find from a comparison of the morphology in H$\\alpha$, HI and dust that while the first two are coincident over most of the disc, they are offset from the dust lanes especially along the inner parts of the spiral arms: a picture which is indicative of a density wave shock moving through the arms. HI is formed near the young massive stars as a result of photo-dissociation. From radial profiles we find that in the region of the star-forming spiral arms the exponential scale lengths for H$\\alpha$, blue and near-infrared light, and 21 cm radio continuum are equal within the fitting errors. The scale lengths for the interarm region are also equal for all these tracers, but the arm scale lengths are significantly longer. This points to a common origin of the profiles in star formation, with little or no influence from radial population gradients or dust in the disc of this galaxy. The longer arm scale lengths are equivalent to an outwardly increasing arm-interarm contrast. We argue that the radial profiles of radio continuum and HI, as well as CO, are also directly regulated by star formation, and discuss the possible implications of this result for the interpretation of observed CO intensities in and outside spiral arms. We discuss the radial atomic hydrogen profile in some detail. Its almost perfectly flat shape in the region of the star-forming spiral arms may be explained by photodissociation and recombination processes in the presence of a limited

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

    SciTech Connect (OSTI)

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

    2014-12-10

    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.

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

    E-Print Network [OSTI]

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

    2007-02-01

    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.

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

    E-Print Network [OSTI]

    Yi, Bingqi

    2013-07-09

    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...

  14. Particle trap to sheath non-binding contact for a gas-insulated transmission line having a corrugated outer conductor

    DOE Patents [OSTI]

    Fischer, William H. (Pittsburgh, PA)

    1984-04-24

    A non-binding particle trap to outer sheath contact for use in gas insulated transmission lines having a corrugated outer conductor. The non-binding feature of the contact according to the teachings of the invention is accomplished by having a lever arm rotatably attached to a particle trap by a pivot support axis disposed parallel to the direction of travel of the inner conductor/insulator/particle trap assembly.

  15. Hybrid particle traps and conditioning procedure for gas insulated transmission lines

    DOE Patents [OSTI]

    Dale, Steinar J. (Monroeville, PA); Cookson, Alan H. (Churchill, PA)

    1982-01-01

    A gas insulated transmission line includes an outer sheath, an inner condor within the outer sheath, insulating supports supporting the inner conductor within the outer sheath, and an insulating gas electrically insulating the inner conductor from the outer sheath. An apertured particle trapping ring is disposed within the outer sheath, and the trapping ring has a pair of dielectric members secured at each longitudinal end thereof, with the dielectric members extending outwardly from the trapping ring along an arc. A support sheet having an adhesive coating thereon is secured to the trapping ring and disposed on the outer sheath within the low field region formed between the trapping ring and the outer sheath. A conditioning method used to condition the transmission line prior to activation in service comprises applying an AC voltage to the inner conductor in a plurality of voltage-time steps, with the voltage-time steps increasing in voltage magnitude while decreasing in time duration.

  16. Advanced coal-fueled industrial cogeneration gas turbine system particle removal system development

    SciTech Connect (OSTI)

    Stephenson, M.

    1994-03-01

    Solar Turbines developed a direct coal-fueled turbine system (DCFT) and tested each component in subscale facilities and the combustion system was tested at full-scale. The combustion system was comprised of a two-stage slagging combustor with an impact separator between the two combustors. Greater than 90 percent of the native ash in the coal was removed as liquid slag with this system. In the first combustor, coal water slurry mixture (CWM) was injected into a combustion chamber which was operated loan to suppress NO{sub x} formation. The slurry was introduced through four fuel injectors that created a toroidal vortex because of the combustor geometry and angle of orientation of the injectors. The liquid slag that was formed was directed downward toward an impaction plate made of a refractory material. Sixty to seventy percent of the coal-borne ash was collected in this fashion. An impact separator was used to remove additional slag that had escaped the primary combustor. The combined particulate collection efficiency from both combustors was above 95 percent. Unfortunately, a great deal of the original sulfur from the coal still remained in the gas stream and needed to be separated. To accomplish this, dolomite or hydrated lime were injected in the secondary combustor to react with the sulfur dioxide and form calcium sulfite and sulfates. This solution for the sulfur problem increased the dust concentrations to as much as 6000 ppmw. A downstream particulate control system was required, and one that could operate at 150 psia, 1850-1900{degrees}F and with low pressure drop. Solar designed and tested a particulate rejection system to remove essentially all particulate from the high temperature, high pressure gas stream. A thorough research and development program was aimed at identifying candidate technologies and testing them with Solar`s coal-fired system. This topical report summarizes these activities over a period beginning in 1987 and ending in 1992.

  17. An efficient particle Fokker–Planck algorithm for rarefied gas flows

    SciTech Connect (OSTI)

    Gorji, M. Hossein; Jenny, Patrick

    2014-04-01

    This paper is devoted to the algorithmic improvement and careful analysis of the Fokker–Planck kinetic model derived by Jenny et al. [1] and Gorji et al. [2]. The motivation behind the Fokker–Planck based particle methods is to gain efficiency in low Knudsen rarefied gas flow simulations, where conventional direct simulation Monte Carlo (DSMC) becomes expensive. This can be achieved due to the fact that the resulting model equations are continuous stochastic differential equations in velocity space. Accordingly, the computational particles evolve along independent stochastic paths and thus no collision needs to be calculated. Therefore the computational cost of the solution algorithm becomes independent of the Knudsen number. In the present study, different computational improvements were persuaded in order to augment the method, including an accurate time integration scheme, local time stepping and noise reduction. For assessment of the performance, gas flow around a cylinder and lid driven cavity flow were studied. Convergence rates, accuracy and computational costs were compared with respect to DSMC for a range of Knudsen numbers (from hydrodynamic regime up to above one). In all the considered cases, the model together with the proposed scheme give rise to very efficient yet accurate solution algorithms.

  18. COARSE-GRID SIMULATION OF REACTING AND NON-REACTING GAS-PARTICLE FLOWS

    SciTech Connect (OSTI)

    Sankaran Sundaresan

    2004-03-01

    The principal goal of this project, funded under the ''DOE Vision 21 Virtual Demonstration Initiative'' is virtual demonstration of circulating fluidized bed performance. We had proposed a ''virtual demonstration tool'', which is based on the open-domain CFD code MFIX. The principal challenge funded through this grant is to devise and implement in this CFD code sound physical models for the rheological characteristics of the gas-particle mixtures. Within the past year, which was the third year of the project, we have made the following specific advances. (a) We have completed a study of the impact of sub-grid models of different levels of detail on the results obtained in coarse-grid simulations of gas-particle flow. (b) We have also completed a study of a model problem to understand the effect of wall friction, which was proved in our earlier work to be very important for stable operation of standpipes in a circulating fluidized bed circuit. These are described in a greater detail in this report.

  19. Nuclear Disks of Gas and Dust in Early Type Galaxies and the Hunt for Massive Black Holes: Hubble Space Telescope Observations of NGC 6251

    E-Print Network [OSTI]

    Laura Ferrarese; Holland Ford

    1998-11-19

    We discuss Hubble Space Telescope optical images and spectra of NGC 6251, a giant E2 galaxy and powerful radio source at a distance of 106 Mpc (for H_0 = 70 km/s/Mpc). The galaxy is known to host a very well defined dust disk (O'Neil et al. 1994); the exceptional resolution of our V and I images allows a detailed study of the disk structure. Furthermore, narrow band images centered on the Halpha+[NII] emission lines, reveal the presence of ionized gas in the inner 0.3 arcsec of the disk. We used the HST/Faint Object Spectrograph with the 0.09 arcsec aperture to study the velocity structure of the disk. Dynamical models were constructed for two extreme (in terms of central concentration) analytical representations of the stellar surface brightness profile, from which the mass density and corresponding rotational velocity are derived assuming a constant mass-to-light ratio (M/L)_V ~ 8.5 M_solar/L_solar. For both representations of the stellar component, the models show that the gas is in Keplerian motion around a central mass ~ 4 - 8 X 10^8 solar masses, and that the contribution of radial flows to the velocity field is negligible.

  20. EFFECTS OF DUST GROWTH AND SETTLING ON THE IONIZATION BY RADIONUCLIDES. I. FORMULATION AND RESULTS IN A QUIESCENT STATE OF PROTOPLANETARY DISKS

    SciTech Connect (OSTI)

    Umebayashi, Toyoharu; Katsuma, Norihito; Nomura, Hideko

    2013-02-10

    We investigate the evolution of the ionization rates by the decay of radionuclides in protoplanetary disks at the early stage of planet formation where size growth and settling of dust particles proceed extensively. Because most of the nuclides to ionize gas, such as short-lived nuclide {sup 26}Al and long-lived one {sup 40}K, are refractory elements, they are contained in the solid material of dust particles. Thus, the ionization by these nuclides is affected by the following three processes: (1) the change of the relative abundance of dust particles due to the settling toward the midplane of the disk, (2) the energy loss of emitted energetic particles inside the solid material of dust particles, and (3) the absorption of energetic particles by the other dust particles located nearby. In this series of papers we comprehensively investigate the basic physical processes, calculate the settling and size growth of dust particles numerically, and clarify the evolution of the ionization rates relative to their initial values in various disk models at this stage. In this paper we investigate the energy-loss processes concerning dust particles, formulate the coalescence equation for settling particles, and apply them to quiescent disk models that are similar to the solar nebula. For simplicity, dust particles are assumed to be compact spheres that remain perfect sticking for mutual collisions. Because the settling of dust particles is not appreciable in the first 10{sup 3} yr, the ionization rate varies little except in the outermost part near the disk surface. As the settling proceeds, the rate around the midplane increases considerably. The maximum ionization rates by {sup 26}Al in the minimum mass solar nebula are about 100, 51, and 14 times larger than their initial values for the orbits R = 0.5, 1, and 5 AU, respectively, which are close to or exceed the ionization rate by cosmic ray in the interstellar medium. The rates by {sup 40}K also increase by factors of about 36, 19, and 5 at the same orbits. In the inner orbital regions, these rates exceed the rates by the attenuated cosmic rays by an order of magnitude. The rates in the residual parts decrease extensively as time goes by, because amounts of the floating dust particles decrease continuously.

  1. Karl G. Jansky very large array observations of cold dust and molecular gas in starbursting quasar host galaxies at z ? 4.5

    SciTech Connect (OSTI)

    Wagg, J.; Carilli, C. L.; Lentati, L.; Maiolino, R.; Hills, R.; Aravena, M.; Cox, P.; McMahon, R. G.; Riechers, D.; Walter, F.; Andreani, P.; Wolfe, A.

    2014-03-10

    We present Karl G. Jansky Very Large Array (VLA) observations of 44 GHz continuum and CO J = 2-1 line emission in BRI 1202–0725 at z = 4.7 (a starburst galaxy and quasar pair) and BRI 1335–0417 at z = 4.4 (also hosting a quasar). With the full 8 GHz bandwidth capabilities of the upgraded VLA, we study the (rest-frame) 250 GHz thermal dust continuum emission for the first time along with the cold molecular gas traced by the low-J CO line emission. The measured CO J = 2-1 line luminosities of BRI 1202–0725 are L{sub CO}{sup ?}=(8.7±0.8)×10{sup 10} K km s{sup –1} pc{sup 2} and L{sub CO}{sup ?}=(6.0 ± 0.5)×10{sup 10} K km s{sup –1} pc{sup 2} for the submillimeter galaxy (SMG) and quasar, respectively, which are equal to previous measurements of the CO J = 5-4 line luminosities implying thermalized line emission, and we estimate a combined cold molecular gas mass of ?9×10{sup 10} M {sub ?}. In BRI 1335–0417 we measure L{sub CO}{sup ?}=(7.3±0.6)×10{sup 10} K km s{sup –1} pc{sup 2}. We detect continuum emission in the SMG BRI 1202–0725 North (S {sub 44} {sub GHz} = 51 ± 6 ?Jy), while the quasar is detected with S {sub 44} {sub GHz} = 24 ± 6 ?Jy and in BRI 1335–0417 we measure S {sub 44} {sub GHz} = 40 ± 7 ?Jy. Combining our continuum observations with previous data at (rest-frame) far-infrared and centimeter wavelengths, we fit three-component models in order to estimate the star formation rates. This spectral energy distribution fitting suggests that the dominant contribution to the observed 44 GHz continuum is thermal dust emission, while either thermal free-free or synchrotron emission contributes less than 30%.

  2. Uranium mill ore dust characterization

    SciTech Connect (OSTI)

    Knuth, R.H.; George, A.C.

    1980-11-01

    Cascade impactor and general air ore dust measurements were taken in a uranium processing mill in order to characterize the airborne activity, the degree of equilibrium, the particle size distribution and the respirable fraction for the /sup 238/U chain nuclides. The sampling locations were selected to limit the possibility of cross contamination by airborne dusts originating in different process areas of the mill. The reliability of the modified impactor and measurement techniques was ascertained by duplicate sampling. The results reveal no significant deviation from secular equilibrium in both airborne and bulk ore samples for the /sup 234/U and /sup 230/Th nuclides. In total airborne dust measurements, the /sup 226/Ra and /sup 210/Pb nuclides were found to be depleted by 20 and 25%, respectively. Bulk ore samples showed depletions of 10% for the /sup 226/Ra and /sup 210/Pb nuclides. Impactor samples show disequilibrium of /sup 226/Ra as high as +-50% for different size fractions. In these samples the /sup 226/Ra ratio was generally found to increase as particle size decreased. Activity median aerodynamic diameters of the airborne dusts ranged from 5 to 30 ..mu..m with a median diameter of 11 ..mu..m. The maximum respirable fraction for the ore dusts, based on the proposed International Commission on Radiological Protection's (ICRP) definition of pulmonary deposition, was < 15% of the total airborne concentration. Ore dust parameters calculated for impactor duplicate samples were found to be in excellent agreement.

  3. DEVELOPMENT OF A NEW HIGH TEMPERATURE GAS RECEIVER UTILIZING SMALL PARTICLES

    E-Print Network [OSTI]

    Hunt, Arlon J.

    2012-01-01

    for powering a gas turbine or to supply industrial processin conjunetion with a gas turbine system providing severalincluding heating a gas to operate a turbine (4), providing

  4. THREE-DIMENSIONAL LAGRANGIAN TURBULENT DIFFUSION OF DUST GRAINS IN A PROTOPLANETARY DISK: METHOD AND FIRST APPLICATIONS

    SciTech Connect (OSTI)

    Charnoz, Sebastien; Aleon, Jerome

    2011-08-10

    In order to understand how the chemical and isotopic compositions of dust grains in a gaseous turbulent protoplanetary disk are altered during their journey in the disk, it is important to determine their individual trajectories. We study here the dust-diffusive transport using Lagrangian numerical simulations using the popular 'turbulent diffusion' formalism. However, it is naturally expressed in an Eulerian form, which does not allow the trajectories of individual particles to be studied. We present a simple stochastic and physically justified procedure for modeling turbulent diffusion in a Lagrangian form that overcomes these difficulties. We show that a net diffusive flux F of the dust appears and that it is proportional to the gas density ({rho}) gradient and the dust diffusion coefficient D{sub d}: (F = D{sub d} /{rho} x grad({rho})). It induces an inward transport of dust in the disk's midplane, while favoring outward transport in the disk's upper layers. We present tests and applications comparing dust diffusion in the midplane and upper layers as well as sample trajectories of particles with different sizes. We also discuss potential applications for cosmochemistry and smoothed particle hydrodynamic codes.

  5. On the dust environment of comet C/2012 S1 (ISON) from 12 AU...

    Office of Scientific and Technical Information (OSTI)

    COSMOLOGY AND ASTRONOMY; ALFVEN WAVES; COMETS; CONFIGURATION; DENSITY; DUSTS; EMISSION; FRAGMENTATION; GALAXY NUCLEI; IMAGES; MASS; MONTE CARLO METHOD; PARTICLES; SPHERES;...

  6. RAPID COAGULATION OF POROUS DUST AGGREGATES OUTSIDE THE SNOW LINE: A PATHWAY TO SUCCESSFUL ICY PLANETESIMAL FORMATION

    SciTech Connect (OSTI)

    Okuzumi, Satoshi; Kobayashi, Hiroshi [Department of Physics, Nagoya University, Nagoya, Aichi 464-8602 (Japan); Tanaka, Hidekazu [Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819 (Japan); Wada, Koji, E-mail: okuzumi@nagoya-u.jp [Planetary Exploration Research Center, Chiba Institute of Technology, Narashino, Chiba 275-0016 (Japan)

    2012-06-20

    Rapid orbital drift of macroscopic dust particles is one of the major obstacles to planetesimal formation in protoplanetary disks. We re-examine this problem by considering the porosity evolution of dust aggregates. We apply a porosity model based on recent N-body simulations of aggregate collisions, which allows us to study the porosity change upon collision for a wide range of impact energies. As a first step, we neglect collisional fragmentation and instead focus on dust evolution outside the snow line, where the fragmentation has been suggested to be less significant than inside the snow line because of the high sticking efficiency of icy particles. We show that dust particles can evolve into highly porous aggregates (with internal densities of much less than 0.1 g cm{sup -3}) even if collisional compression is taken into account. We also show that the high porosity triggers significant acceleration in collisional growth. This acceleration is a natural consequence of the particles' aerodynamical properties at low Knudsen numbers, i.e., at particle radii larger than the mean free path of the gas molecules. Thanks to this rapid growth, the highly porous aggregates are found to overcome the radial drift barrier at orbital radii less than 10 AU (assuming the minimum-mass solar nebula model). This suggests that, if collisional fragmentation is truly insignificant, formation of icy planetesimals is possible via direct collisional growth of submicron-sized icy particles.

  7. Correlation function intercepts for $\\tilde?,q$-deformed Bose gas model implying effective accounting for interaction and compositeness of particles

    E-Print Network [OSTI]

    A. M. Gavrilik; Yu. A. Mishchenko

    2015-07-23

    In the recently proposed two-parameter $\\tilde{\\mu},q$-deformed Bose gas model [Ukr. J. Phys. {\\bf 58}, 1171 (2013), arXiv:1312.1573] aimed to take effectively into account both compositeness of particles and their interaction, the $\\tilde{\\mu},q$-deformed virial expansion of the equation of state (EOS) was obtained. In this paper we further explore the $\\tilde{\\mu},q$-deformation, namely the version of $\\tilde{\\mu},q$-Bose gas model involving deformed distributions and correlation functions. In the model, we explicitly derive the one- and two-particle deformed distribution functions and the intercept of two-particle momentum correlation function. The results are illustrated by plots, and the comparison with known experimental data on two-pion correlation function intercepts extracted in RHIC/STAR experiments is given.

  8. Computer tomography of large dust clouds in complex plasmas

    SciTech Connect (OSTI)

    Killer, Carsten; Himpel, Michael; Melzer, André

    2014-10-15

    The dust density is a central parameter of a dusty plasma. Here, a tomography setup for the determination of the three-dimensionally resolved density distribution of spatially extended dust clouds is presented. The dust clouds consist of micron-sized particles confined in a radio frequency argon plasma, where they fill almost the entire discharge volume. First, a line-of-sight integrated dust density is obtained from extinction measurements, where the incident light from an LED panel is scattered and absorbed by the dust. Performing these extinction measurements from many different angles allows the reconstruction of the 3D dust density distribution, analogous to a computer tomography in medical applications.

  9. Composition and Reactions of Atmospheric Aerosol Particles

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

    Composition and Reactions of Atmospheric Aerosol Particles Print Microscopic aerosol particles in the atmosphere contain carbonaceous components from mineral dust and combustion...

  10. Glass Frit Clumping And Dusting

    SciTech Connect (OSTI)

    Steimke, J. L.

    2013-09-26

    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

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

    E-Print Network [OSTI]

    Fang, Guangyang

    2012-07-16

    an important role in climate change, the majorities of aerosols are natural ones and can impact cloud properties, convective cloud dynamics, and the development of tropical storms (Jones et al. 2004). The optical properties of mineral dust aerosols... dusts from the Rayleigh regime to the geometric optics regime. A database of the optical properties of randomly oriented spheroids has been developed. 4.1 Geometry of the dust particle model The geometry of the spheroidal model used is shown...

  12. Importance Sampling Variance Reduction for the Fokker-Planck Rarefied Gas Particle Method

    E-Print Network [OSTI]

    Collyer, Benjamin; Lockerby, Duncan

    2015-01-01

    Models and methods that are able to accurately and efficiently predict the flows of low-speed rarefied gases are in high demand, due to the increasing ability to manufacture devices at micro and nano scales. One such model and method is a Fokker-Planck approximation to the Boltzmann equation, which can be solved numerically by a stochastic particle method. The stochastic nature of this method leads to noisy estimates of the thermodynamic quantities one wishes to sample when the signal is small in comparison to the thermal velocity of the gas. Recently, Gorji et al have proposed a method which is able to greatly reduce the variance of the estimators, by creating a correlated stochastic process which acts as a control variate for the noisy estimates. However, there are potential difficulties involved when the geometry of the problem is complex, as the method requires the density to be solved for independently. Importance sampling is a variance reduction technique that has already been shown to successfully redu...

  13. Mathematical Simulation of the Gas-Particles Reaction Flows in Incineration of Metal-Containing Waste

    SciTech Connect (OSTI)

    Ojovan, M. I.; Klimov, V. L.; Karlina, O. K.

    2002-02-26

    A ''quasi-equilibrium'' approach for thermodynamic calculation of chemical composition and properties of metal-containing fuel combustion products has been developed and used as a part of the mathematical model of heterogeneous reacting flow which carry burning and/or evaporating particles. By using of this approach, the applicable mathematical model has been devised, which allows defining the change in chemical composition and thermal characteristics of combustion products along the incineration chamber. As an example, the simulation results of the reacting flow of magnesium-sodium nitrate-organic mixture are presented. The simulation results on the gas phase temperature in the flow of combustion products are in good agreement with those obtained experimentally. The proposed method of ''quasi-equilibrium'' thermodynamic calculation and mathematical model provide a real possibility for performing of numerical experiments on the basis of mathematical simulation of nonequilibrium flows of combustion products. Numerical experiments help correctly to estimate the work characteristics in the process of treatment devices design saving time and costs.

  14. Apparatus to collect, classify, concentrate, and characterize gas-borne particles

    DOE Patents [OSTI]

    Rader, Daniel J.; Torczynski, John R.; Wally, Karl; Brockmann, John E.

    2003-12-16

    An aerosol lab-on-a-chip (ALOC) integrates one or more of a variety of particle collection, classification, concentration (enrichment), an characterization processes onto a single substrate or layered stack of such substrates. By mounting a UV laser diode laser light source on the substrate, or substrates tack, so that it is located down-stream of the sample inlet port and at right angle the sample particle stream, the UV light source can illuminate individual particles in the stream to induce a fluorescence response in those particles having a fluorescent signature such as biological particles, some of said particles. An illuminated particle having a fluorescent signal above a threshold signal would trigger a sorter module that would separate that particle from the particle stream.

  15. The dust acoustic waves in three dimensional scalable complex plasma

    E-Print Network [OSTI]

    Zhukhovitskii, D I

    2015-01-01

    Dust acoustic waves in the bulk of a dust cloud in complex plasma of low pressure gas discharge under microgravity conditions are considered. The dust component of complex plasma is assumed a scalable system that conforms to the ionization equation of state (IEOS) developed in our previous study. We find singular points of this IEOS that determine the behavior of the sound velocity in different regions of the cloud. The fluid approach is utilized to deduce the wave equation that includes the neutral drag term. It is shown that the sound velocity is fully defined by the particle compressibility, which is calculated on the basis of the scalable IEOS. The sound velocities and damping rates calculated for different 3D complex plasmas both in ac and dc discharges demonstrate a good correlation with experimental data that are within the limits of validity of the theory. The theory provides interpretation for the observed independence of the sound velocity on the coordinate and for a weak dependence on the particle ...

  16. 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]

    Grounds, Stephanie Beth

    2012-02-14

    Thermal Emission Spectrometer (Mini- TES) thermal infrared spectra (Smith et al., 2006). MER-based Mini-TES spectra have been used in the determination of generalized boundary layer parameters for Martian GCMs. Mini-TES spectra were collected in both... superadiabatic layer found near the surface (Smith et al., 2006). Mini-TES observations were used to observe general timescales, duration times, and overall intensities of multiple local- and regional-scale dust storms, and upward-looking Mini-TES research can...

  17. Flow Mapping in a Gas-Solid Riser via Computer Automated Radioactive Particle Tracking (CARPT)

    SciTech Connect (OSTI)

    Muthanna Al-Dahhan; Milorad P. Dudukovic; Satish Bhusarapu; Timothy J. O'hern; Steven Trujillo; Michael R. Prairie

    2005-06-04

    Statement of the Problem: Developing and disseminating a general and experimentally validated model for turbulent multiphase fluid dynamics suitable for engineering design purposes in industrial scale applications of riser reactors and pneumatic conveying, require collecting reliable data on solids trajectories, velocities ? averaged and instantaneous, solids holdup distribution and solids fluxes in the riser as a function of operating conditions. Such data are currently not available on the same system. Multiphase Fluid Dynamics Research Consortium (MFDRC) was established to address these issues on a chosen example of circulating fluidized bed (CFB) reactor, which is widely used in petroleum and chemical industry including coal combustion. This project addresses the problem of lacking reliable data to advance CFB technology. Project Objectives: The objective of this project is to advance the understanding of the solids flow pattern and mixing in a well-developed flow region of a gas-solid riser, operated at different gas flow rates and solids loading using the state-of-the-art non-intrusive measurements. This work creates an insight and reliable database for local solids fluid-dynamic quantities in a pilot-plant scale CFB, which can then be used to validate/develop phenomenological models for the riser. This study also attempts to provide benchmark data for validation of Computational Fluid Dynamic (CFD) codes and their current closures. Technical Approach: Non-Invasive Computer Automated Radioactive Particle Tracking (CARPT) technique provides complete Eulerian solids flow field (time average velocity map and various turbulence parameters such as the Reynolds stresses, turbulent kinetic energy, and eddy diffusivities). It also gives directly the Lagrangian information of solids flow and yields the true solids residence time distribution (RTD). Another radiation based technique, Computed Tomography (CT) yields detailed time averaged local holdup profiles at various planes. Together, these two techniques can provide the needed local solids flow dynamic information for the same setup under identical operating conditions, and the data obtained can be used as a benchmark for development, and refinement of the appropriate riser models. For the above reasons these two techniques were implemented in this study on a fully developed section of the riser. To derive the global mixing information in the riser, accurate solids RTD is needed and was obtained by monitoring the entry and exit of a single radioactive tracer. Other global parameters such as Cycle Time Distribution (CTD), overall solids holdup in the riser, solids recycle percentage at the bottom section of the riser were evaluated from different solids travel time distributions. Besides, to measure accurately and in-situ the overall solids mass flux, a novel method was applied.

  18. Dust studies in DIII-D and TEXTOR

    SciTech Connect (OSTI)

    Rudakov, D.L.; Litnovsky, A; West, W. P.; Yu, J.H.; Boedo, J.A.; McLean, Adam G

    2009-01-01

    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. Submicrometre 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. 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; on the other hand, large flakes or debris falling into the plasma may induce a disruption. Migration of pre-characterized carbon dust is studied in DIII-D and TEXTOR by introducing micrometre-size particles into plasma discharges. In DIII-D, a sample holder filled with 30-40 mg of dust is inserted in the lower divertor and exposed, via sweeping of the strike points, to the diverted plasma flux of high-power ELMing H-mode discharges. After a brief dwell (similar to 0.1 s) of the outer strike point on the sample holder, part of the dust penetrates into the core plasma, raising the core carbon density by a factor of 2-3 and resulting in a twofold increase in 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 1.4 MW of NBI. Launched in this configuration, the dust perturbed the edge plasma, as evidenced by a moderate increase in the edge carbon content, but did not penetrate into the core plasma.

  19. Effects of thermal radiation heat transfer on flame acceleration and transition to detonation in dust cloud flames: Origins of dust explosion

    E-Print Network [OSTI]

    Ivanov, Michael A Liberman M F

    2015-01-01

    We examines regimes of the hydrogen flames propagation and ignition of mixtures heated by the radiation emitted from the flame. The gaseous phase is assumed to be transparent for radiation, while the suspended particles of the dust cloud ahead of the flame absorb and reemit the radiation. The radiant heat absorbed by the particles is then lost by conduction to the surrounding unreacted gaseous phase so that the gas phase temperature lags that of the particles. The direct numerical simulations solve the full system of two phase gas dynamic time-dependent equations with a detailed chemical kinetics for a plane flames propagating through a dust cloud. Depending on the spatial distribution of the dispersed particles and on the value of radiation absorption length the consequence of the radiative preheating of the unreacted mixture can be either the increase of the flame velocity for uniformly dispersed particles or ignition deflagration or detonation ahead of the flame via the Zel'dovich gradient mechanism in the...

  20. Dust Studies in DIII-D and TEXTOR

    SciTech Connect (OSTI)

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

    2009-02-17

    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.

  1. Simultaneous factor analysis of organic particle and gas1 mass spectra: AMS and PTR-MS measurements at an2

    E-Print Network [OSTI]

    Meskhidze, Nicholas

    S1 Simultaneous factor analysis of organic particle and gas1 mass spectra: AMS and PTR: Traffic F2PTR: LRT + Local Source F3PTR: LRT + Painting F4PTR: LRT + Local Oxidation F5PTR: Oxygenates+Local Source) F3PTR (LRT+Painting) F4PTR: Local Oxidation F5PTR: Oxygenates fPeak = -1.0 fPeak = 0 fPeak = 1

  2. Global estimates of mineral dust aerosol iron and aluminum solubility that account for particle size using diffusion-controlled and surface-area-controlled approximations

    E-Print Network [OSTI]

    2012-01-01

    state dissolution kinetics of goethite in the presence of= 3 [Wehrli et al. , 1990]. Goethite/hematite are thought toFor laboratory- ground goethite and hematite particles, an

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

    E-Print Network [OSTI]

    Glen, Andrew

    2014-01-15

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

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

    SciTech Connect (OSTI)

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

    2011-11-29

    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.

  5. Numerical determination of the material properties of porous dust cakes

    E-Print Network [OSTI]

    D. Paszun; C. Dominik

    2008-02-13

    The formation of planetesimals requires the growth of dust particles through collisions. Micron-sized particles must grow by many orders of magnitude in mass. In order to understand and model the processes during this growth, the mechanical properties, and the interaction cross sections of aggregates with surrounding gas must be well understood. Recent advances in experimental (laboratory) studies now provide the background for pushing numerical aggregate models onto a new level. We present the calibration of a previously tested model of aggregate dynamics. We use plastic deformation of surface asperities as the physical model to bring critical velocities for sticking into accordance with experimental results. The modified code is then used to compute compression strength and the velocity of sound in the aggregate at different densities. We compare these predictions with experimental results and conclude that the new code is capable of studying the properties of small aggregates.

  6. Transparent self-cleaning dust shield

    DOE Patents [OSTI]

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

    2005-06-28

    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.

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

    SciTech Connect (OSTI)

    Kakati, B. Kalita, D.; Kausik, S. S.; Saikia, B. K.; Bandyopadhyay, M.

    2014-08-15

    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.

  8. Effect of Synthesis Condition and Annealing on the Sensitivity and Stability of Gas Sensors Made of Zn-Doped y-Fe2O3 Particles 

    E-Print Network [OSTI]

    Kim, Taeyang

    2010-10-12

    In this study, the effect of synthesis conditions and annealing process on the sensitivity and stability of gas sensors made of flame-synthesized Zn-doped ?-Fe2O3 particles was investigated. Zn-doped ?-Fe2O3 particles were synthesized by flame...

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

    E-Print Network [OSTI]

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

    2007-01-01

    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...

  10. DEVELOPMENT OF A NEW HIGH TEMPERATURE GAS RECEIVER UTILIZING SMALL PARTICLES

    E-Print Network [OSTI]

    Hunt, Arlon J.

    2012-01-01

    Symposium on Solar Thermal Power and Energy Systems,solar to thermal conversion is accomplished by a dispersion of ultra~fine partlcles suspended in a gas to absorb radlant energy

  11. Flue gas conditioning for improved particle collection in electrostatic precipitators. Quarterly technical report, July 1--September 30, 1992

    SciTech Connect (OSTI)

    Durham, M.D.

    1992-10-14

    By injecting high concentrations of SO{sub 3} (80 to 100 ppM) it was possible to reduce the particle resistivity from 10{sup 11} to 10{sup 7} ohm-cm. However, it was very difficult to consistently obtain intermediate levels of resistivity. This was because of the steep relationships between gas phase SO{sub 3} and resistivity. It only takes a few ppM of SO{sub 3} to provide an order of magnitude change in resistivity. This is demonstrated by the curves in Figure 2. The water dew point for a gas stream with a moisture content of 10%, which is typical of coal fired boilers, is approximately 120{degrees}F. However, in a flue gas with only 2 ppM of SO{sub 3}, sulfuric acid will begin to condense at 270{degrees}F. The effect of the rapid rise in acid dew point is reflected by the corresponding rapid decrease in resistivity. With no gas phase SO{sub 3} present the resistivity is in the high 10{sup 11} ohm-cm range. However with only 10 ppM of SO{sub 3}, the resistivity drops three orders of magnitude. Therefore, intermediate levels of resistivity can only be obtained by controlling the SO{sub 3} concentration within 1 or 2 ppM.

  12. Shock Interaction with Dust Layers 

    E-Print Network [OSTI]

    Chowdhury, Amira Yousuf

    2015-06-02

    Dust explosion hazards in areas where combustible dusts are found have caused loss of life and halted business operations in some instances. The elimination of secondary dust explosion hazards, i.e. reducing dust dispersion, ...

  13. Niamey Dust Observations

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

    Flynn, Connor

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

  14. Niamey Dust Observations

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

    Flynn, Connor

    2008-10-01

    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.

  15. Ejecta Particle-Size Measurements in Vacuum and Helium Gas using Ultraviolet In-Line Fraunhofer Holography

    SciTech Connect (OSTI)

    Sorenson, Danny S.; Pazuchanics, Peter; Johnson, Randall P.; Malone, R. M.; Kaufman, M. I.; Tibbitts, A.; Tunnell, T.; Marks, D.; Capelle, G. A.; Grover, M.; Marshall, B.; Stevens, G. D.; Turley, W. D.; LaLone, B.

    2014-06-25

    An Ultraviolet (UV) in-line Fraunhofer holography diagnostic has been developed for making high-resolution spatial measurements of ejecta particles traveling at many mm/?sec. This report will discuss the development of the diagnostic including the high-powered laser system and high-resolution optical relay system. In addition, the system required to reconstruct the images from the hologram and the corresponding analysis of those images to extract particles will also be described. Finally, results from six high-explosive (HE), shock-driven Sn ejecta experiments will be presented. Particle size distributions will be shown that cover most of the ejecta velocities for experiments conducted in a vacuum, and helium gas environments. In addition, a modification has been made to the laser system that produces two laser pulses separated by 6.8 ns. This double-pulsed capability allows a superposition of two holograms to be acquired at two different times, thus allowing ejecta velocities to be measured directly. Results from this double pulsed experiment will be described.

  16. Ejecta Particle-Size Measurements in Vacuum and Helium Gas using Ultraviolet In-Line Fraunhofer Holography

    SciTech Connect (OSTI)

    Sorenson, D. S.; Pazuchanics, P.; Johnson, R.; Malone, R. M.; Kaufman, M. I.; Tibbitts, A.; Tunnell, T.; Marks, D.; Capelle, G. A.; Grover, M.; Marshall, B.; Stevens, G. D.; Turley, W. D.; LaLone, B.

    2014-06-30

    An ultraviolet (UV) in-line Fraunhofer holography diagnostic has been developed for making high-resolution spatial measurements of ejecta particles traveling at many mm/?sec. This report will discuss the development of the diagnostic, including the high-powered laser system and high-resolution optical relay system. In addition, we will also describe the system required to reconstruct the images from the hologram and the corresponding analysis of those images to extract particles. Finally, we will present results from six high-explosive (HE), shock-driven Sn-ejecta experiments. Particle-size distributions will be shown that cover most of the ejecta velocities for experiments conducted in a vacuum, and helium gas environments. In addition, a modification has been made to the laser system that produces two laser pulses separated by 6.8 ns. This double-pulsed capability allows a superposition of two holograms to be acquired at two different times, thus allowing ejecta velocities to be measured directly. Results from this double-pulsed experiment will be described.

  17. Tensile & shear strength of porous dust agglomerates

    E-Print Network [OSTI]

    Alexander Seizinger; Roland Speith; Wilhelm Kley

    2013-08-23

    Context.Within the sequential accretion scenario of planet formation, planets are build up through a sequence sticking collisions. The outcome of collisions between porous dust aggregates is very important for the growth from very small dust particles to planetesimals. In this work we determine the necessary material properties of dust aggregates as a function the porosity. Aims: Continuum models such as SPH that are capable of simulating collisions of macroscopic dust aggregates require a set of material parameters. Some of them such as the tensile and shear strength are ?difficult to obtain from laboratory experiments. The aim of this work is to determine these parameters from ab-initio molecular dynamics simulations. Methods: We simulate the behavior of porous dust aggregates using a detailed micro-physical model of the interaction of spherical grains that includes adhesion forces, rolling, twisting, and sliding. Using different methods of preparing the samples we study the strength behavior of our samples with varying porosity and coordination number of the material. Results: For the tensile strength, we can reproduce data from laboratory experiments very well. For the shear strength, there are no experimental data available. The results from our simulations differ significantly from previous theoretical models, which indicates that the latter might not be sufficient to describe porous dust aggregates. Conclusions: We have provided functional behavior of tensile and shear strength of porous dust aggregates as a function of the porosity that can be directly applied in continuum simulations of these objects in planet formation scenarios.

  18. Dust Combustion Safety Issues for Fusion Applications

    SciTech Connect (OSTI)

    L. C. Cadwallader

    2003-05-01

    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.

  19. Survivability of dust in tokamaks: dust transport in the divertor sheath

    E-Print Network [OSTI]

    Delzanno, Gian Luca

    2014-01-01

    The survivability of dust being transported in the magnetized sheath near the divertor plate of a tokamak and its impact on the mandatory balance of erosion and redeposition for a steady-state reactor are investigated. Two different divertor scenarios are considered. The first is characterized by an energy flux perpendicular to the plate $q_0\\simeq 1$ MW/m$^2$ typical of current short-pulse tokamaks. The second has $q_0\\simeq 10$ MW/m$^2$ and is relevant to long-pulse machines like ITER or DEMO. It is shown that micrometer dust particles can survive rather easily near the plates of a divertor plasma with $q_0\\simeq 1$ MW/m$^2$ because thermal radiation provides adequate cooling for the dust particle. On the other hand, the survivability of micrometer dust particles near the divertor plates is drastically reduced when $q_0\\simeq 10$ MW/m$^2$. Micrometer dust particles redeposit their material non-locally, leading to a net poloidal mass migration across the divertor. Smaller particles (with radius $\\sim 0.1$ $\\...

  20. Dust size distribution and concentrations with cottonseed oil mills 

    E-Print Network [OSTI]

    Wiederhold, Lee Roy

    1976-01-01

    -VOLUME SAMPLES FOR P. S. D OF PARTICLES & 100 um DIAMETER (MMD) ANALYSIS OF VARIANCE ON HIGH-VOLUME SAMPLES FOR P. S. D. OF PARTICLES & 100 um DIAMETER (og) MULTIPLE RANGE TEST FOR MEAN VALUES OF MMD BY AREA MULTIPLE RANGE TEST OF MMD BY MILL PARTICLE SIZE... TEST OF AREA DUST CONCENTRATIONS = 15 Pm IN DIAMETER MULTIPLE RANGE TEST OF MILL DUST CONCENTRATIONS & 15 um IN DIAMETER ANALYSIS OF VARIANCE ON PARTICLE SIZING HEAD SAMPLES OF CONCENTRATIONS FOR PARTICLES & 100 IJBI DIAMETER . . . . 47 47 54...

  1. Particle Emission Characteristics of a Gas Turbine with a Double Annular Combustor

    E-Print Network [OSTI]

    Boies, Adam M.; Stettler, Marc E. J.; Swanson, Jacob J.; Johnson, Jacob J.; Johnson, Tyler J.; Olfert, Jason S.; Eggersdorfer, Max L.; Rindlisbacher, Theo; Wang, Jing; Thomson, Kevin; Smallwood, Greg; Sevcenco, Yura; Walters, David; Williams, Paul I.; Corbin, Joel; Mensah, Amewu A.; Symonds, Jonathan; Dastanpour, Ramin; Rogak, Steven N.

    2015-07-15

    of sulfuric acid 60 (Zhang et al., 2008). In addition to the size characteristics of PM, the toxicity of PM may 61 depend upon the composition, surface chemistry and surface charge (Bakand et al., 2012). 62 Modelling studies have shown that morphology can... relation via density (?), 𝑚p = 𝜌𝜋𝑑p 3/6, 𝑚p = 𝜌𝑉. For non-spherical particles, similar 239 parameters are used to define effective metrics of diameter, mass and volume. This study 240 employs and tests the following analytical and semi...

  2. A long Saharan dust event over the western Mediterranean: Lidar, Sun photometer observations, and regional dust modeling

    E-Print Network [OSTI]

    over the Mediterranean region (http://www.bsc.es/projects/earthscience/ DREAM/) considering four of dust exported annually from northern Africa (Sahara-Sahel region) are still not reliable, and range]. Once in the atmosphere, dust particles interact with solar and thermal radiation, modulating the Earth

  3. Particle simulation of collision dynamics for ion beam injection into a rarefied gas

    SciTech Connect (OSTI)

    Giuliano, Paul N.; Boyd, Iain D.

    2013-03-15

    This study details a comparison of ion beam simulations with experimental data from a simplified plasma test cell in order to study and validate numerical models and environments representative of electric propulsion devices and their plumes. The simulations employ a combination of the direct simulation Monte Carlo and particle-in-cell methods representing xenon ions and atoms as macroparticles. An anisotropic collision model is implemented for momentum exchange and charge exchange interactions between atoms and ions in order to validate the post-collision scattering behaviors of dominant collision mechanisms. Cases are simulated in which the environment is either collisionless or non-electrostatic in order to prove that the collision models are the dominant source of low- and high-angle particle scattering and current collection within this environment. Additionally, isotropic cases are run in order to show the importance of anisotropy in these collision models. An analysis of beam divergence leads to better characterization of the ion beam, a parameter that requires careful analysis. Finally, suggestions based on numerical results are made to help guide the experimental design in order to better characterize the ion environment.

  4. Assessment of suspended dust from pipe rattling operations 

    E-Print Network [OSTI]

    Park, Ju-Myon

    2006-10-30

    . The PM10 sampler provides a reasonable estimate of the thoracic particulate fraction. The RespiCon sampler provides an unbiased estimate of respirable, thoracic, and inhalable fractions. DustTrak and SidePak monitors provide relative particle...

  5. Advanced Gas Reactor Fuel Program's TRISO Particle Fuel Sets A New World

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

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirleyEnergyTher i n c i p a l De p u t y A sCOLONY PROJECTRecord For Irradiation Performance |

  6. Thermal creep assisted dust lifting on Mars: Wind tunnel experiments for the entrainment threshold velocity

    E-Print Network [OSTI]

    Küpper, Markus

    2015-01-01

    In this work we present laboratory measurements on the reduction of the threshold friction velocity necessary for lifting dust if the dust bed is illuminated. Insolation of a porous soil establishes a temperature gradient. At low ambient pressure this gradient leads to thermal creep gas flow within the soil. This flow leads to a sub-surface overpressure which supports lift imposed by wind. The wind tunnel was run with Mojave Mars Simulant and air at 3, 6 and 9 mbar, to cover most of the pressure range at martian surface levels. Our first measurements imply that the insolation of the martian surface can reduce the entrainment threshold velocity between 4 % and 19 % for the conditions sampled with our experiments. An insolation activated soil might therefore provide additional support for aeolian particle transport at low wind speeds.

  7. SMALL PARTICLE HEAT EXCHANGERS

    E-Print Network [OSTI]

    Hunt, A.J.

    2011-01-01

    The Small Particle Heat Exchange Receiver (SPHER) for Solarof the small particle heat exchange receiver (or SPHER), asabsorption process, the heat exchange to the gas, the choice

  8. Apparatus to collect, classify, concentrate, and characterize gas-borne particles

    DOE Patents [OSTI]

    Rader, Daniel J. (Albuquerque, NM); Torczynski, John R. (Albuquerque, NM); Wally, Karl (Lafayette, CA); Brockmann, John E. (Albuquerque, NM)

    2002-01-01

    An aerosol lab-on-a-chip (ALOC) integrates one or more of a variety of aerosol collection, classification, concentration (enrichment), and characterization processes onto a single substrate or layered stack of such substrates. By taking advantage of modern micro-machining capabilities, an entire suite of discrete laboratory aerosol handling and characterization techniques can be combined in a single portable device that can provide a wealth of data on the aerosol being sampled. The ALOC offers parallel characterization techniques and close proximity of the various characterization modules helps ensure that the same aerosol is available to all devices (dramatically reducing sampling and transport errors). Micro-machine fabrication of the ALOC significantly reduces unit costs relative to existing technology, and enables the fabrication of small, portable ALOC devices, as well as the potential for rugged design to allow operation in harsh environments. Miniaturization also offers the potential of working with smaller particle sizes and lower pressure drops (leading to reduction of power consumption).

  9. DUST FORMATION IN MACRONOVAE

    SciTech Connect (OSTI)

    Takami, Hajime; Ioka, Kunihito [Institute of Particle and Nuclear Studies, KEK, 1-1, Oho, Tsukuba 305-0801 (Japan); Nozawa, Takaya, E-mail: takami@post.kek.jp, E-mail: kunihito.ioka@kek.jp, E-mail: takaya.nozawa@nao.ac.jp [National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2014-07-01

    We examine dust formation in macronovae (as known as kilonovae), which are the bright ejecta of neutron star binary mergers and one of the leading sites of r-process nucleosynthesis. In light of information about the first macronova candidate associated with GRB 130603B, we find that dust grains of r-process elements have difficulty forming because of the low number density of the r-process atoms, while carbon or elements lighter than iron can condense into dust if they are abundant. Dust grains absorb emission from ejecta with an opacity even greater than that of the r-process elements, and re-emit photons at infrared wavelengths. Such dust emission can potentially account for macronovae without r-process nucleosynthesis as an alternative model. This dust scenario predicts a spectrum with fewer features than the r-process model and day-scale optical-to-ultraviolet emission.

  10. Dust resuspension as a contaminant source and transport pathway

    SciTech Connect (OSTI)

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

    1999-07-01

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

  11. Star-forming regions at the periphery of the supershell surrounding the Cyg OB1 association. I. The star cluster vdB 130 and its ambient gas and dust medium

    E-Print Network [OSTI]

    Sitnik, T G; Lozinskaya, T A; Moiseev, A V; Rastorguev, A S; Tatarnikov, A M; Tatarnikova, A A; Wiebe, D S; Zabolotskikh, M V

    2015-01-01

    Stellar population and the interstellar gas-dust medium in the vicinity of the open star cluster vdB 130 are analysed using optical observations taken with the 6-m telescope of the SAO RAS and the 125-cm telescope of the SAI MSU along with the data of Spitzer and Herschel. Based on proper motions and BV and JHKs 2MASS photometric data, we select additional 36 stars as probable cluster members. Some stars in vdB 130 are classified as B stars. Our estimates of minimum colour excess, apparent distance modulus and the distance are consistent with young age (from 5 to 10 Myrs) of the cluster vdB 130. We suppose the large deviations from the conventional extinction law in the cluster direction, with $R_V$ ~ 4 - 5. The cluster vdB 130 appears to be physically related to the supershell around Cyg OB1, a cometary CO cloud, ionized gas, and regions of infrared emission. There are a few regions of bright mid-infrared emission in the vicinity of vdB 130. The largest of them is also visible on H-alpha and [SII] emission m...

  12. 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]

    Otani, Niels F.

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

  13. Hot Gas Filtration of Fine and Ultra fine Particles with Liquid Phase Sintered SiC Ceramic DPF

    Broader source: Energy.gov [DOE]

    Basics of particle collection and desogn of filters for diesel soot particles are discussed. Parameters which influence back pressure and filter loading are described.

  14. Nanodiamond dust and the far-ultraviolet quasar break

    E-Print Network [OSTI]

    Binette, L; Morisset, C; Haro-Corzo, S; De Diego, J A; Mutschke, H; Andersen, A C

    2005-01-01

    We explore the possibility that the steepening observed shortward of 1000A in the energy distribution of quasars may result from absorption by dust, being either intrinsic to the quasar environment or intergalactic. We find that a dust extinction curve consisting of nanodiamonds, composed of terrestrial cubic diamonds or with surface impurities as found in carbonaceous chondrite meteorites, such as Allende, is successful in reproducing the sharp break observed. The intergalactic dust model is partially successful in explaining the shape of the composite energy distribution, but must be discarded in the end, as the amount of crystalline dust required is unreasonable and would imply an improbable fine tuning among the dust formation processes. The alternative intrinsic dust model requires a mixture of both cubic diamonds and Allende nanodiamonds and provide a better fit of the UV break. The gas column densities implied are of the order 10^{20} cm^{-2} assuming solar metallicity for carbon and full depletion of ...

  15. Particle preconcentrator

    DOE Patents [OSTI]

    Linker, Kevin L. (Albuquerque, NM); Conrad, Frank J. (Russellville, NM); Custer, Chad A. (Albuquerque, NM); Rhykerd, Jr., Charles L. (Albuquerque, NM)

    1998-01-01

    An apparatus and method for preconcentrating particles and vapors. The preconcentrator apparatus permits detection of highly diluted amounts of particles in a main gas stream, such as a stream of ambient air. A main gas stream having airborne particles entrained therein is passed through a pervious screen. The particles accumulate upon the screen, as the screen acts as a sort of selective particle filter. The flow of the main gas stream is then interrupted by diaphragm shutter valves, whereupon a cross-flow of carrier gas stream is blown parallel past the faces of the screen to dislodge the accumulated particles and carry them to a particle or vapor detector, such as an ion mobility spectrometer. The screen may be heated, such as by passing an electrical current there through, to promote desorption of particles therefrom during the flow of the carrier gas. Various types of screens are disclosed. The apparatus and method of the invention may find particular utility in the fields of narcotics, explosives detection and chemical agents.

  16. Particle preconcentrator

    DOE Patents [OSTI]

    Linker, Kevin L. (Albuquerque, NM); Conrad, Frank J. (Russellville, SC); Custer, Chad A. (Albuquerque, NM); Rhykerd, Jr., Charles L. (Albuquerque, NM)

    2000-01-01

    An apparatus and method for preconcentrating particles and vapors. The preconcentrator apparatus permits detection of highly diluted amounts of particles in a main gas stream, such as a stream of ambient air. A main gas stream having airborne particles entrained therein is passed through a pervious screen. The particles accumulate upon the screen, as the screen acts as a sort of selective particle filter. The flow of the main gas stream is then interrupted by diaphragm shutter valves, whereupon a cross-flow of carrier gas stream is blown parallel past the faces of the screen to dislodge the accumulated particles and carry them to a particle or vapor detector, such as an ion mobility spectrometer. The screen may be heated, such as by passing an electrical current there through, to promote desorption of particles therefrom during the flow of the carrier gas. Various types of screens are disclosed. The apparatus and method of the invention may find particular utility in the fields of narcotics, explosives detection and chemical agents.

  17. Particle preconcentrator

    SciTech Connect (OSTI)

    Linker, Kevin L.; Conrad, Frank J.; Custer, Chad A.; Rhykerd, Jr., Charles L.

    2005-09-20

    An apparatus and method for preconcentrating particles and vapors. The preconcentrator apparatus permits detection of highly diluted amounts of particles in a main gas stream, such as a stream of ambient air. A main gas stream having airborne particles entrained therein is passed through a pervious screen. The particles accumulate upon the screen, as the screen acts as a sort of selective particle filter. The flow of the main gas stream is then interrupted by diaphragm shutter valves, whereupon a cross-flow of carrier gas stream is blown parallel past the faces of the screen to dislodge the accumulated particles and carry them to a particle or vapor detector, such as an ion mobility spectrometer. The screen may be heated, such as by passing an electrical current there through, to promote desorption of particles therefrom during the flow of the carrier gas. Various types of screens are disclosed. The apparatus and method of the invention may find particular utility in the fields of narcotics, explosives detection and chemical agents.

  18. Particle preconcentrator

    DOE Patents [OSTI]

    Linker, K.L.; Conrad, F.J.; Custer, C.A.; Rhykerd, C.L. Jr.

    1998-12-29

    An apparatus and method are disclosed for preconcentrating particles and vapors. The preconcentrator apparatus permits detection of highly diluted amounts of particles in a main gas stream, such as a stream of ambient air. A main gas stream having airborne particles entrained therein is passed through a pervious screen. The particles accumulate upon the screen, as the screen acts as a sort of selective particle filter. The flow of the main gas stream is then interrupted by diaphragm shutter valves, whereupon a cross-flow of carrier gas stream is blown parallel past the faces of the screen to dislodge the accumulated particles and carry them to a particle or vapor detector, such as an ion mobility spectrometer. The screen may be heated, such as by passing an electrical current there through, to promote desorption of particles therefrom during the flow of the carrier gas. Various types of screens are disclosed. The apparatus and method of the invention may find particular utility in the fields of narcotics, explosives detection and chemical agents. 3 figs.

  19. Dust around Type Ia supernovae

    E-Print Network [OSTI]

    Wang, Lifan

    2005-01-01

    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

  20. PERFORMANCE ANALYSIS OF A WINDOWED HIGH TEMPERATURE GAS RECEIVER USING A SUSPENSION OF ULTRAFINE CARBON PARTICLES AS THE SOLAR ABSORBER

    E-Print Network [OSTI]

    Fisk, William J.

    2012-01-01

    from the compressor of a gas turbine and passes on to thewith a regenerated gas turbine sys- tem providing severaltemperature for powering a gas turbine or to supply indus-

  1. Particle impact damping: influence of material and size 

    E-Print Network [OSTI]

    Marhadi, Kun Saptohartyadi

    2005-02-17

    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...

  2. Study on multiphase flow and mixing in semidry flue gas desulfurization with a multifluid alkaline spray generator using particle image velocimetry

    SciTech Connect (OSTI)

    Zhou, Y.G.; Wang, D.F.; Zhang, M.C. [Shanghai Jiao Tong University, Shanghai (China)

    2009-06-15

    Particle image velocimetry (PIV) technique was used to measure the velocity fields of gas-droplet-solid multiphase flow in the experimental setup of a novel semidry flue gas desulfurization process with a multifluid alkaline spray generator. The flow structure, mixing characteristic, and interphase interaction of gas-droplet-solid multiphase flow were investigated both in the confined alkaline spray generator and in the duct bent pipe section. The results show that sorbent particles in the confined alkaline spray generator are entrained into the spray core zone by a high-speed spray jet and most of the sorbent particles can be effectively humidified by spray water fine droplets to form aqueous lime slurry droplets. Moreover, a minimum amount of air stream in the generator is necessary to achieve higher collision humidification efficiency between sorbent particles and spray water droplets and to prevent the possible deposition of fine droplets on the wall. The appropriate penetration length of the slurry droplets from the generator can make uniform mixing between the formed slurry droplets and main air stream in the duct bent pipe section, which is beneficial to improving sulfur dioxide removal efficiency and to preventing the deposition of droplets on the wall.

  3. Benchmarking of the MIT High Temperature Gas-cooled Reactor TRISO-coated particle fuel performance model

    E-Print Network [OSTI]

    Stawicki, Michael A

    2006-01-01

    MIT has developed a Coated Particle Fuel Performance Model to study the behavior of TRISO nuclear fuels. The code, TIMCOAT, is designed to assess the mechanical and chemical condition of populations of coated particles and ...

  4. Origin of Interplanetary Dust through Optical Properties of Zodiacal Light

    E-Print Network [OSTI]

    Yang, Hongu

    2015-01-01

    This study investigates the origin of interplanetary dust particles (IDPs) through the optical properties, albedo and spectral gradient, of zodiacal light. The optical properties were compared with those of potential parent bodies in the solar system, which include D-type (as analogue of cometary nuclei), C-type, S-type, X-type, and B-type asteroids. We applied Bayesian inference on the mixture model made from the distribution of these sources, and found that >90% of the interplanetary dust particles originate from comets (or its spectral analogues, D-type asteroids). Although some classes of asteroids (C-type and X-type) may make a moderate contribution, ordinary chondrite-like particles from S-type asteroids occupy a negligible fraction of the interplanetary dust cloud complex. The overall optical properties of the zodiacal light were similar to those of chondritic porous IDPs, supporting the dominance of cometary particles in zodiacal cloud.

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

    SciTech Connect (OSTI)

    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)

    2013-04-01

    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.

  6. Inorganic hazardous air pollutants before and after a limestone flue gas desulfurization system as a function of <10 micrometer particle sizes and unit load

    SciTech Connect (OSTI)

    Maxwell, D.P.; Williams, W.A.; Flora, H.B. II [Radian Corp., Austin, TX (United States)

    1995-12-31

    Radian Corporation collected size-fractionated particulate samples from stack gas at a unit burning high sulfur coal with a venturi scrubber FGD system. Independent sample fractions were collected under high-load and low-load operating conditions and subjected to various techniques designed to measure the total composition and surface-extractable concentrations of selected trace elements. The relationships between unit load, particle-size distribution, total composition, and surface-extractable inorganic species are reported and compared to show the availability of trace elements relevant to potential health risks from flue gas particulate emissions.

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

    SciTech Connect (OSTI)

    Kakati, B. Kausik, S. S.; Saikia, B. K.; Bandyopadhyay, M.; Saxena, Y. C.

    2014-10-28

    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.

  8. 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)

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

    2009-12-10

    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.

  9. Newton to Einstein — dust to dust

    SciTech Connect (OSTI)

    Kopp, Michael; Uhlemann, Cora; Haugg, Thomas E-mail: cora.uhlemann@physik.lmu.de

    2014-03-01

    We investigate the relation between the standard Newtonian equations for a pressureless fluid (dust) and the Einstein equations in a double expansion in small scales and small metric perturbations. We find that parts of the Einstein equations can be rewritten as a closed system of two coupled differential equations for the scalar and transverse vector metric perturbations in Poisson gauge. It is then shown that this system is equivalent to the Newtonian system of continuity and Euler equations. Brustein and Riotto (2011) conjectured the equivalence of these systems in the special case where vector perturbations were neglected. We show that this approach does not lead to the Euler equation but to a physically different one with large deviations already in the 1-loop power spectrum. We show that it is also possible to consistently set to zero the vector perturbations which strongly constrains the allowed initial conditions, in particular excluding Gaussian ones such that inclusion of vector perturbations is inevitable in the cosmological context. In addition we derive nonlinear equations for the gravitational slip and tensor perturbations, thereby extending Newtonian gravity of a dust fluid to account for nonlinear light propagation effects and dust-induced gravitational waves.

  10. Spatiotemporal evolution of dielectric driven cogenerated dust density waves

    SciTech Connect (OSTI)

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

    2013-06-15

    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.

  11. DUST TRANSPORT IN PROTOSTELLAR DISKS THROUGH TURBULENCE AND SETTLING

    SciTech Connect (OSTI)

    Turner, N. J.; Carballido, A. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Sano, T., E-mail: neal.turner@jpl.nasa.go [Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871 (Japan)

    2010-01-01

    We apply ionization balance and magnetohydrodynamical (MHD) calculations to investigate whether magnetic activity moderated by recombination on dust grains can account for the mass accretion rates and the mid-infrared spectra and variability of protostellar disks. The MHD calculations use the stratified shearing-box approach and include grain settling and the feedback from the changing dust abundance on the resistivity of the gas. The two-decade spread in accretion rates among solar-mass T Tauri stars is too large to result solely from variations in the grain size and stellar X-ray luminosity, but can plausibly be produced by varying these parameters together with the disk magnetic flux. The diverse shapes and strengths of the mid-infrared silicate bands can come from the coupling of grain settling to the distribution of the magnetorotational turbulence, through the following three effects. First, recombination on grains 1 mum or smaller yields a magnetically inactive dead zone extending more than two scale heights from the midplane, while turbulent motions in the magnetically active disk atmosphere overshoot the dead zone boundary by only about one scale height. Second, grains deep in the dead zone oscillate vertically in wave motions driven by the turbulent layer above, but on average settle at the rates found in laminar flow, so that the interior of the dead zone is a particle sink and the disk atmosphere will become dust-depleted unless resupplied from elsewhere. Third, with sufficient depletion, the dead zone is thinner and mixing dredges grains off the midplane. The last of these processes enables evolutionary signatures such as the degree of settling to sometimes decrease with age. The MHD results also show that the magnetic activity intermittently lifts clouds of small grains into the atmosphere. Consequently the photosphere height changes by up to one-third over timescales of a few orbits, while the extinction along lines of sight grazing the disk surface varies by factors of 2 over times down to a tenth of an orbit. We suggest that the changing shadows cast by the dust clouds on the outer disk are a cause of the daily to monthly mid-infrared variability found in many young stars.

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

    DOE Patents [OSTI]

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

    1988-01-01

    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.

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

    SciTech Connect (OSTI)

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

    2011-03-15

    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.

  14. Cotton Gin Dust Explosibility Determinations 

    E-Print Network [OSTI]

    Vanderlick, Francis Jerome

    2014-01-06

    the dust for explosibility based on the American Society for Testing and Materials (ASTM) E 1226 to ensure proper regulation of facilities. Dusts found in cotton gins were tested to determine if they are explosible. Safety Consulting Engineers Inc. (SCE...

  15. The erosion of ductile metals by solid particles

    E-Print Network [OSTI]

    Hutchings, Ian Michael

    1975-02-04

    kgm- 2s - 1 ) but there are obvious implications of this result in the design of accelerated erosion tests. 1.2.9 Chemical effe cts - ero s ion/ corrosion Many practical cases of dust erosion take place in hig hly corrosive environments... are entrained in a fast - flowing gas stream which accelerates them down a tube. The velocity with which t hey leave the tube depends upon a number of variables, and careful attention must be p.:dcl to the s e if a reasonably uniform particle velocity...

  16. Nanodiamond dust and the far-ultraviolet quasar break

    E-Print Network [OSTI]

    L. Binette; G. Magris C.; Y. Krongold; C. Morisset; S. Haro-Corzo; J. A. de Diego; H. Mutschke; A. C. Andersen

    2005-05-29

    We explore the possibility that the steepening observed shortward of 1000A in the energy distribution of quasars may result from absorption by dust, being either intrinsic to the quasar environment or intergalactic. We find that a dust extinction curve consisting of nanodiamonds, composed of terrestrial cubic diamonds or with surface impurities as found in carbonaceous chondrite meteorites, such as Allende, is successful in reproducing the sharp break observed. The intergalactic dust model is partially successful in explaining the shape of the composite energy distribution, but must be discarded in the end, as the amount of crystalline dust required is unreasonable and would imply an improbable fine tuning among the dust formation processes. The alternative intrinsic dust model requires a mixture of both cubic diamonds and Allende nanodiamonds and provide a better fit of the UV break. The gas column densities implied are of the order 10^{20} cm^{-2} assuming solar metallicity for carbon and full depletion of carbon into dust. The absorption only occurs in the ultraviolet and is totally negligible in the visible. The minimum dust mass required is of the order ~ 0.003 r_{pc}^{2}M_o, where r_{pc} is the distance in parsec between the dust screen and the continuum source. The intrinsic dust model reproduces the flux {\\it rise} observed around 660A in key quasar spectra quite well. We present indirect evidence of a shallow continuum break near 670A (18.5 eV), which would be intrinsic to the quasar continuum.

  17. Study of Particle Rotation Effect in Gas-Solid Flows using Direct Numerical Simulation with a Lattice Boltzmann Method

    SciTech Connect (OSTI)

    Kwon, Kyung; Fan, Liang-Shih; Zhou, Qiang; Yang, Hui

    2014-09-30

    A new and efficient direct numerical method with second-order convergence accuracy was developed for fully resolved simulations of incompressible viscous flows laden with rigid particles. The method combines the state-of-the-art immersed boundary method (IBM), the multi-direct forcing method, and the lattice Boltzmann method (LBM). First, the multi-direct forcing method is adopted in the improved IBM to better approximate the no-slip/no-penetration (ns/np) condition on the surface of particles. Second, a slight retraction of the Lagrangian grid from the surface towards the interior of particles with a fraction of the Eulerian grid spacing helps increase the convergence accuracy of the method. An over-relaxation technique in the procedure of multi-direct forcing method and the classical fourth order Runge-Kutta scheme in the coupled fluid-particle interaction were applied. The use of the classical fourth order Runge-Kutta scheme helps the overall IB-LBM achieve the second order accuracy and provides more accurate predictions of the translational and rotational motion of particles. The preexistent code with the first-order convergence rate is updated so that the updated new code can resolve the translational and rotational motion of particles with the second-order convergence rate. The updated code has been validated with several benchmark applications. The efficiency of IBM and thus the efficiency of IB-LBM were improved by reducing the number of the Lagragian markers on particles by using a new formula for the number of Lagrangian markers on particle surfaces. The immersed boundary-lattice Boltzmann method (IBLBM) has been shown to predict correctly the angular velocity of a particle. Prior to examining drag force exerted on a cluster of particles, the updated IB-LBM code along with the new formula for the number of Lagrangian markers has been further validated by solving several theoretical problems. Moreover, the unsteadiness of the drag force is examined when a fluid is accelerated from rest by a constant average pressure gradient toward a steady Stokes flow. The simulation results agree well with the theories for the short- and long-time behavior of the drag force. Flows through non-rotational and rotational spheres in simple cubic arrays and random arrays are simulated over the entire range of packing fractions, and both low and moderate particle Reynolds numbers to compare the simulated results with the literature results and develop a new drag force formula, a new lift force formula, and a new torque formula. Random arrays of solid particles in fluids are generated with Monte Carlo procedure and Zinchenko's method to avoid crystallization of solid particles over high solid volume fractions. A new drag force formula was developed with extensive simulated results to be closely applicable to real processes over the entire range of packing fractions and both low and moderate particle Reynolds numbers. The simulation results indicate that the drag force is barely affected by rotational Reynolds numbers. Drag force is basically unchanged as the angle of the rotating axis varies.

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

    E-Print Network [OSTI]

    Duffy, Thomas S.

    . The Raman measurements indicate that the production of carbon dust particles in NSTX involves modifications to be similar to those measured for carbon deposits from atmospheric pressure helium arc discharge responsible for dust production: (i) evap- oration and sublimation of thermally overloaded wall material

  19. Atmospheric Environment 39 (2005) 359369 Dust composition and mixing state inferred from airborne

    E-Print Network [OSTI]

    Clarke, Antony

    2005-01-01

    . Dust-laden air masses that had mixed with urban air pollutants over the Beijing and Tianjin region were and Technology (GIST), Gwangju 500-712, South Korea c Department of Oceanography, University of Hawaii, Honolulu and NO3 À . The results point to an external mixture of mineral dust and urban pollutant particles

  20. Design of an Online Fission Gas Monitoring System for Post-irradiation Examination Heating Tests of Coated Fuel Particles for High-Temperature Gas-Cooled Reactors

    SciTech Connect (OSTI)

    Dawn Scates

    2010-10-01

    A new Fission Gas Monitoring System (FGMS) has been designed at the Idaho National Laboratory (INL) for use of monitoring online fission gas-released during fuel heating tests. The FGMS will be used with the Fuel Accident Condition Simulator (FACS) at the Hot Fuels Examination Facility (HFEF) located at the Materials and Fuels Complex (MFC) within the INL campus. Preselected Advanced Gas Reactor (AGR) TRISO (Tri-isotropic) fuel compacts will undergo testing to assess the fission product retention characteristics under high temperature accident conditions. The FACS furnace will heat the fuel to temperatures up to 2,000ºC in a helium atmosphere. Released fission products such as Kr and Xe isotopes will be transported downstream to the FGMS where they will accumulate in cryogenically cooledcollection traps and monitored with High Purity Germanium (HPGe) detectors during the heating process. Special INL developed software will be used to monitor the accumulated fission products and will report data in near real-time. These data will then be reported in a form that can be readily available to the INL reporting database. This paper describes the details of the FGMS design, the control and acqusition software, system calibration, and the expected performance of the FGMS. Preliminary online data may be available for presentation at the High Temperature Reactor (HTR) conference.

  1. Light Scattering by Ice Crystals and Mineral Dust Aerosols in the Atmosphere 

    E-Print Network [OSTI]

    Bi, Lei

    2012-07-16

    Modeling the single-scattering properties of nonspherical particles in the atmo¬sphere (in particular, ice crystals and dust aerosols) has important applications to climate and remote sensing studies. The ?rst part of the dissertation (Chapters II...

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

    E-Print Network [OSTI]

    Seok, Ji Yeon; Hirashita, Hiroyuki

    2015-01-01

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

  3. Dynamics of the electric current in an ideal electron gas: a sound mode inside the quasi-particles

    E-Print Network [OSTI]

    Sašo Grozdanov; Janos Polonyi

    2015-09-03

    We study the equation of motion for the Noether current in an electron gas within the framework of the Schwinger-Keldysh Closed-Time-Path formalism. The equation is shown to be highly non-linear and irreversible even for a non-interacting, ideal gas of electrons at non-zero density. We truncate the linearised equation of motion, written as the Laurent series in Fourier space, so that the resulting expressions are local in time, both at zero and at small finite temperatures. Furthermore, we show that the one-loop Coulomb interactions only alter the physical picture quantitatively, while preserving the characteristics of the dynamics that the electric current exhibits in the absence of interactions. As a result of the composite nature of the Noether current, {\\it composite sound} waves are found to be the dominant IR collective excitations at length scales between the inverse Fermi momentum and the mean free path that would exist in an interacting electron gas. We also discuss the difference and the transition between the hydrodynamical regime of an ideal gas, defined in this work, and the hydrodynamical regime in phenomenological hydrodynamics, which is normally used for the description of interacting gases.

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

    SciTech Connect (OSTI)

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

    2015-01-01

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

  5. Gas-flow measurements in a jet flame using cross-correlation of high speed particle-images

    SciTech Connect (OSTI)

    Shioji, Masahiro; Kawasaki, Kiyoshi; Kawanabe, Hiroshi; Ikegami, Makoto

    1999-07-01

    Time changes of a two-dimensional distribution of velocities in a methane jet flame and a nitrogen jet are measured by cross-correlation particle image velocimetry (PIV). The mean velocity and the intensity of turbulence are obtained and compared with those measured by HWA in order to ascertain the accuracy of PIV. Furthermore, the effect of combustion on turbulence characteristics is discussed based on the deformation of eddies with time change and distribution of time and spatial scales.

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

    SciTech Connect (OSTI)

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

    2008-09-01

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

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

    E-Print Network [OSTI]

    Plemons, Dorothy Sue

    1981-01-01

    0, um P 30. 0 40. 0 50. 0 FIG. l Hlnimum explosive concentration as a function of particle diameter and distance between particles, the highest levels measured at transfer points. From studies at Texas AFM University, Parnell and 8arton (1979... ) found dust levels in wheat and grain sorghum from a terminal elevator vary from 1000 to 5000 grams of dust less than 100 um per metric ton of grain (2 to 10 pounds per ton). Levels of dust in grain sorghum samples collected by Parnell (1981...

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

    SciTech Connect (OSTI)

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

    2013-11-05

    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.

  9. Dynamics of the electric current in an ideal electron gas: a sound mode inside the quasi-particles

    E-Print Network [OSTI]

    Grozdanov, Sašo

    2015-01-01

    We study the equation of motion for the Noether current in an electron gas within the framework of the Schwinger-Keldysh Closed-Time-Path formalism. The equation is shown to be highly non-linear and irreversible even for a non-interacting, ideal gas of electrons at non-zero density. We truncate the linearised equation of motion, written as the Laurent series in Fourier space, so that the resulting expressions are local in time, both at zero and at small finite temperatures. Furthermore, we show that the one-loop Coulomb interactions only alter the physical picture quantitatively, while preserving the characteristics of the dynamics that the electric current exhibits in the absence of interactions. As a result of the composite nature of the Noether current, composite sound waves are found to be the dominant IR collective excitations at length scales between the inverse Fermi momentum and the mean free path that would exist in an interacting electron gas. We also discuss the difference and the transition betwee...

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

    E-Print Network [OSTI]

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

    2013-01-01

    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...

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

    SciTech Connect (OSTI)

    Paul W. Humrickhouse

    2011-06-01

    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.

  12. Search for particle emission from a gas-loaded deuterium-palladium system in the alpha-beta phase

    SciTech Connect (OSTI)

    Nicholson, J.P.

    1996-12-01

    Neutron and proton emission due to possible solid state fusion events is monitored from a palladium sample loaded with deuterium gas to atomic fractions up to 0.7. Most of the experimental runs show no detectable activity above background rates, indicating a fusion rate <2.7x10{sup -22} s{sup -1}/deuterium-deuterium (D-D) pair. Two brief excursions by the proton counter might indicate a temporary rate of 3.5x10{sup -21} s{sup -1}/D-D pair. 25 refs., 1 fig.

  13. DUST FORMATION, EVOLUTION, AND OBSCURATION EFFECTS IN THE VERY HIGH-REDSHIFT UNIVERSE

    SciTech Connect (OSTI)

    Dwek, Eli; Benford, Dominic J. [Observational Cosmology Lab., Code 665, NASA at Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Staguhn, Johannes; Su, Ting [Also at Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA. (United States); Arendt, Richard G. [Also at CRESST, University of Maryland Baltimore County, Baltimore, MD 21250, USA. (United States); Kovacks, Attila, E-mail: eli.dwek@nasa.gov [Also at Astronomy Department, CalTech, Pasadena, CA 90025, USA. (United States)

    2014-06-20

    The evolution of dust at redshifts z ? 9, and consequently the dust properties, differs greatly from that in the local universe. In contrast to the local universe, core collapse supernovae (CCSNe) are the only source of thermally condensed dust. Because of the low initial dust-to-gas mass ratio, grain destruction rates are low, so that CCSNe are net producers of interstellar dust. Galaxies with large initial gas mass or high mass infall rate will therefore have a more rapid net rate of dust production compared to galaxies with lower gas mass, even at the same star formation rate. The dust composition is dominated by silicates, which exhibit a strong rise in the UV opacity near the Lyman break. This ''silicate-UV break'' may be confused with the Lyman break, resulting in a misidentification of a galaxy's photometric redshift. In this Letter we demonstrate these effects by analyzing the spectral energy distribution of MACS1149-JD, a lensed galaxy at z = 9.6. A potential 2 mm counterpart of MACS1149-JD has been identified with GISMO. While additional observations are required to corroborate this identification, we use this possible association to illustrate the physical processes and the observational effects of dust in the very high-redshift universe.

  14. PARTICLE IMAGE VELOCIMETRY MEASUREMENTS IN A REPRESENTATIVE GAS-COOLED PRISMATIC REACTOR CORE MODEL: FLOW IN THE COOLANT CHANNELS AND INTERSTITIAL BYPASS GAPS

    SciTech Connect (OSTI)

    Thomas E. Conder; Richard Skifton; Ralph Budwig

    2012-11-01

    Core bypass flow is one of the key issues with the prismatic Gas Turbine-Modular Helium Reactor, and it refers to the coolant that navigates through the interstitial, non-cooling passages between the graphite fuel blocks instead of traveling through the designated coolant channels. To determine the bypass flow, a double scale representative model was manufactured and installed in the Matched Index-of-Refraction flow facility; after which, stereo Particle Image Velocimetry (PIV) was employed to measure the flow field within. PIV images were analyzed to produce vector maps, and flow rates were calculated by numerically integrating over the velocity field. It was found that the bypass flow varied between 6.9-15.8% for channel Reynolds numbers of 1,746 and 4,618. The results were compared to computational fluid dynamic (CFD) pre-test simulations. When compared to these pretest calculations, the CFD analysis appeared to under predict the flow through the gap.

  15. New technology suppresses coke dust

    SciTech Connect (OSTI)

    Not Available

    1983-09-01

    A brief account is given of the technique of electrostatic fogging which has been tested successfully at a Canadian steel mill to control coke dust in the respirable size range. A spray of very fine droplets (<10 MUm) has an electrostatic charge imparted to each droplet. The spray of electrostatically-charged fog suppresses the dust by a combination of scrubbing and electrostatic attraction.

  16. The Feasibility of Shading the Greenhouse with Dust Clouds at the Stable Lunar Lagrange Points

    E-Print Network [OSTI]

    Curtis Struck

    2007-01-25

    There are many indications that anthropogenic global warming poses a serious threat to our civilization and its ecological support systems. Ideally this problem will be overcome by reducing greenhouse gas emissions. Various space-based methods, including large-scale solar shades, diffusers or atmospheric pollutants, have been considered to reduce the solar constant (input flux) and the warming in case emissions reductions are not achieved in a timely way. Here it is pointed out that proposed technologies for near-Earth orbiting comet deflection, suggest a different kind of space-based solar shade. This shade would be made up of micron-sized dust particles derived from comet fragments or lunar mining, and positioned in orbits near the triangular Lagrange points of the Earth-Moon system. Solar radiation pressure can render such orbits unstable, but a class of nearly resonant, and long-lived orbits is shown to exist, though the phase space volume of such orbits depends on dust grain size. Advantages and disadvantages of this scheme relative to others are considered.

  17. Chemistry of atmospheric aerosol particles and their resulting warm cloud-nucleation properties

    E-Print Network [OSTI]

    Moore, Meagan Julia Kerry

    2011-01-01

    for CCN activation, Atmospheric Chemistry and Physics, 10,and precipitation, Atmospheric Chemistry and Physics, 9,dust particles. Atmospheric Chemistry and Physics, 2009, 9,

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

    SciTech Connect (OSTI)

    Abbas, M. M.; Craven, P. D.; LeClair, A. C.; Spann, J. F.; Tankosic, D.

    2010-08-01

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

  19. El Roque de Los Muchachos Site Characteristics. III. Analysis of Atmospheric Dust and Aerosol Extinction

    E-Print Network [OSTI]

    Lombardi, G; Ortolani, S; Pedani, M; Ghedina, A

    2008-01-01

    Canary Islands are normally interested by dominant North-East winds that, in some meteorological conditions, can transport sand at high altitude from the Sahara desert. The dust may affect the efficiency of the telescopes and decreases the transparency of the sky. In order to maximize the scientific return of the telescopes located at the ORM, we present an analysis of the atmospheric dust content and its effects on astronomical observations. B, V and I dust aerosol astronomical extinction are derived. Using a 5 years series database of data taken from the four channel TNG dust monitor, we compute a mean hourly and daily values of the dust content. We have detected particles having size 0.3, 0.5, 1.0 and 5.0 um. Using a power law we have derived the content of 10.0 um particles. We found a typical local dust concentration ranging from 3x10^6 particles per cubic meter at 0.3 um, to 10^3 at 5.0 um and 10 at 10.0 um, increasing up to 3 order of magnitudes during the dust storms, with a relative higher increase o...

  20. Extraordinary dust event over Beijing, China, during April 2006: Lidar, Sun photometric, satellite observations and model validation

    E-Print Network [OSTI]

    ratio for the dust particles (84 sr) during the most intense dust period. The DREAM forecast model the Beijing area, are located in Xingjiang and the Inner Mongolia provinces [Sun et al., 2001]. Strong winds [Dillner et al., 2006]. The increasing urbanization and industrialization of the East Asia region

  1. On the dust environment of Main-Belt Comet 313P/Gibbs

    E-Print Network [OSTI]

    Pozuelos, F J; Licandro, J; Moreno, F

    2015-01-01

    We present observations carried out using the 10.4 m Gran Telescopio Canarias and an interpretative model of the dust environment of activated asteroid 313P/Gibbs. We discuss three different models relating to different values of the dust parameters, i.e, dust loss rate, maximum and minimum sizes of particles, power index of the size distribution, and emission pattern. The best model corresponds with an isotropic emission of particles which started on August 1st. The size of grains were in the range of $0.1-2000$ $\\mu$m, with velocities for 100 $\\mu$m particles between $0.4-1.9$ m$~$s$^{-1}$, with a dust production rate in the range of $0.2-0.8$ kg$~$s$^{-1}$. The dust tails' brightness and morphology are best interpreted in terms of a model of sustained and low dust emission driven by water-ice sublimation, spanning since 2014 August 1st, and triggered by a short impulsive event. This event produced an emission of small particles of about 0.1 $\\mu$m with velocities of $\\sim$4 m$~$s$^{-1}$. From our model we ...

  2. Modified Dust and the Small Scale Crisis in CDM

    E-Print Network [OSTI]

    Fabio Capela; Sabir Ramazanov

    2015-04-29

    At large scales and for sufficiently early times, dark matter is described as a pressureless perfect fluid---dust---non-interacting with Standard Model fields. These features are captured by a simple model with two scalars: a Lagrange multiplier and another playing the role of the velocity potential. That model arises naturally in some gravitational frameworks, e.g., the mimetic dark matter scenario. We consider an extension of the model by means of higher derivative terms, such that the dust solutions are preserved at the background level, but there is a non-zero sound speed at the linear level. We associate this {\\it Modified Dust} with dark matter, and study the linear evolution of cosmological perturbations in that picture. The most prominent effect is the suppression of their power spectrum for sufficiently large cosmological momenta. This can be relevant in view of the problems that cold dark matter faces at sub-galactic scales, e.g., the missing satellites problem. At even shorter scales, however, perturbations of Modified Dust are enhanced compared to the predictions of more common particle dark matter scenarios. This is a peculiarity of their evolution in radiation dominated background. We also briefly discuss clustering of Modified Dust. We write the system of equations in the Newtonian limit, and sketch the possible mechanism which could prevent the appearance of caustic singularities. The same mechanism may be relevant in light of the core-cusp problem.

  3. Shocks and dust survival in nearby active galaxies: implications for the alignment effect

    E-Print Network [OSTI]

    M. Villar-Martin; D. De Young; A. Alonso-Herrero; M. Allen; L. Binette

    2001-08-21

    One of the most popular explanations for the so-called alignment effect in high redshift (z>0.7) radio galaxies is the scattering by dust of the hidden quasar light. As shown by De Young (1998) a problem with the dust scattering model is that the short destruction time-scale for dust grains means that they will not survive the passage of the radio jet. We investigate the survival of dust in the extended ionised gas of nearby active galaxies with jet/gas interactions. We discuss the implications on the alignment effect of high redshift (>0.7) radio galaxies. We conclude that although shocks are likely to destroy dust grains in regions of interaction, dust might survive in enough quantities to scatter light from the active nucleus and produce alignment between scattered light and the radio structures. We propose an observational test to investigate the existence of dust in shocked regions based on the sensitivity of calcium to depletion onto dust grains.

  4. El Roque de Los Muchachos Site Characteristics. III. Analysis of Atmospheric Dust and Aerosol Extinction

    E-Print Network [OSTI]

    G. Lombardi; V. Zitelli; S. Ortolani; M. Pedani; A. Ghedina

    2008-03-26

    Canary Islands are normally interested by dominant North-East winds that, in some meteorological conditions, can transport sand at high altitude from the Sahara desert. The dust may affect the efficiency of the telescopes and decreases the transparency of the sky. In order to maximize the scientific return of the telescopes located at the ORM, we present an analysis of the atmospheric dust content and its effects on astronomical observations. B, V and I dust aerosol astronomical extinction are derived. Using a 5 years series database of data taken from the four channel TNG dust monitor, we compute a mean hourly and daily values of the dust content. We have detected particles having size 0.3, 0.5, 1.0 and 5.0 um. Using a power law we have derived the content of 10.0 um particles. We found a typical local dust concentration ranging from 3x10^6 particles per cubic meter at 0.3 um, to 10^3 at 5.0 um and 10 at 10.0 um, increasing up to 3 order of magnitudes during the dust storms, with a relative higher increase of 1.0, 5.0 and 10.0 um particles. The number of local dust storm events is the same in winter- and summertime, but, the average background and storm-related increases in the dust concentration in summer are significantly higher than in winter. In a uniform approximation, during the dust storms, an average height of the dust layer of 2.5 km above the telescope is inferred. During the sand storms La Palma Island is affected by an almost uniform layer extending up to 5 km above the sea level, down, at least the height of the telescope. The visible extinction is dominated by particles at 1.0, 5.0 and 10.0 um. In agreement with the results from Carlsberg Automatic Meridian Circle (CAMC) we find a typical extinction during dust storms of about 0.2 mag/airmass.

  5. Observations of dust acoustic waves driven at high frequencies: Finite dust temperature effects and wave interference

    E-Print Network [OSTI]

    Merlino, Robert L.

    Observations of dust acoustic waves driven at high frequencies: Finite dust temperature effects An experiment has been performed to study the behavior of dust acoustic waves driven at high frequencies f 100 are observed--interference effects between naturally excited dust acoustic waves and driven dust acoustic waves

  6. Evaluation of Alternate Materials for Coated Particle Fuels for the Gas-Cooled Fast Reactor. Laboratory Directed Research and Development Program FY 2006 Final Report

    SciTech Connect (OSTI)

    Paul A. Demkowicz; Karen Wright; Jian Gan; David Petti; Todd Allen; Jake Blanchard

    2006-09-01

    Candidate ceramic materials were studied to determine their suitability as Gas-Cooled Fast Reactor particle fuel coatings. The ceramics examined in this work were: TiC, TiN, ZrC, ZrN, AlN, and SiC. The studies focused on (i) chemical reactivity of the ceramics with fission products palladium and rhodium, (ii) the thermomechanical stresses that develop in the fuel coatings from a variety of causes during burnup, and (iii) the radiation resiliency of the materials. The chemical reactivity of TiC, TiN, ZrC, and ZrN with Pd and Rh were all found to be much lower than that of SiC. A number of important chemical behaviors were observed at the ceramic-metal interfaces, including the formation of specific intermetallic phases and a variation in reaction rates for the different ceramics investigated. Based on the data collected in this work, the nitride ceramics (TiN and ZrN) exhibit chemical behavior that is characterized by lower reaction rates with Pd and Rh than the carbides TiC and ZrC. The thermomechanical stresses in spherical fuel particle ceramic coatings were modeled using finite element analysis, and included contributions from differential thermal expansion, fission gas pressure, fuel kernel swelling, and thermal creep. In general the tangential stresses in the coatings during full reactor operation are tensile, with ZrC showing the lowest values among TiC, ZrC, and SiC (TiN and ZrN were excluded from the comprehensive calculations due to a lack of available materials data). The work has highlighted the fact that thermal creep plays a critical role in the development of the stress state of the coatings by relaxing many of the stresses at high temperatures. To perform ion irradiations of sample materials, an irradiation beamline and high-temperature sample irradiation stage was constructed at the University of Wisconsin’s 1.7MV Tandem Accelerator Facility. This facility is now capable of irradiating of materials to high dose while controlling sample temperature up to 800ºC.

  7. Investigation of techniques to improve continuous air monitors under conditions of high dust loading in environmental setting

    SciTech Connect (OSTI)

    Huang, Suilou; Schery, Stephen D.; Rodgers, John

    2000-06-01

    Improvement in understanding the deposition of ambient dust particles on environmental continuous air monitor (ECAM) filters, reduction of the alpha-particle interference of radon progeny and other radioactive aerosols in different particle size ranges on filters, and development of ECAMs with increased sensitivity under dusty outdoor conditions.

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

    E-Print Network [OSTI]

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

    2011-01-01

    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.

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

    SciTech Connect (OSTI)

    Maeda, K.; Nozawa, T.; Folatelli, G.; Moriya, T. J.; Nomoto, K.; Bersten, M.; Quimby, R. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Sahu, D. K.; Anupama, G. C. [Indian Institute of Astrophysics, Koramangala, Bangalore 560 034 (India); Minowa, Y.; Pyo, T.-S. [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720 (United States); Motohara, K.; Kitagawa, Y. [Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Ueno, I.; Kawabata, K. S.; Yamanaka, M. [Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Kozasa, T. [Department of Cosmosciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan); Iye, M., E-mail: keiichi.maeda@ipmu.jp [National Astronomical Observatory, Mitaka, Tokyo (Japan)

    2013-10-10

    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.

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

    SciTech Connect (OSTI)

    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)

    2011-11-15

    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.

  11. Fragmentation and Evolution of Molecular Clouds. II: The Effect of Dust Heating

    E-Print Network [OSTI]

    Urban, Andrea; Evans, Neal J

    2009-01-01

    We investigate the effect of heating by luminosity sources in a simulation of clustered star formation. Our heating method involves a simplified continuum radiative transfer method that calculates the dust temperature. The gas temperature is set by the dust temperature. We present the results of four simulations, two simulations assume an isothermal equation of state and the two other simulations include dust heating. We investigate two mass regimes, i.e., 84 Msun and 671 Msun, using these two different energetics algorithms. The mass functions for the isothermal simulations and simulations which include dust heating are drastically different. In the isothermal simulation, we do not form any objects with masses above 1 Msun. However, the simulation with dust heating, while missing some of the low-mass objects, forms high-mass objects (~20 Msun) which have a distribution similar to the Salpeter IMF. The envelope density profiles around the stars formed in our simulation match observed values around isolated, l...

  12. Understanding the 30-year Barbados desert dust record

    E-Print Network [OSTI]

    Mahowald, Natalie M; Zender, C. S.; Luo, C.; Savoie, D.; Torres, O.; del Corral, J.

    2002-01-01

    UNDERSTANDING THE 30-YEAR BARBADOS DESERT DUST Moulin, C. ,on mineral dust in the Barbados trade winds, Nature, 320,Understanding the 30-year Barbados desert dust record, J.

  13. RAPID DUST FORMATION IN NOVAE: THE SPEED CLASS—FORMATION TIMESCALE CORRELATION EXPLAINED

    SciTech Connect (OSTI)

    Williams, S. C.; Bode, M. F.; Darnley, M. J.; Evans, A.; Zubko, V.; Shafter, A. W.

    2013-11-10

    Observations show that the time of onset of dust formation in classical novae depends strongly on their speed class, with dust typically taking longer to form in slower novae. Using empirical relationships between speed class, luminosity and ejection velocity, it can be shown that dust formation timescale is expected to be essentially independent of speed class. However, following a nova outburst the spectrum of the central hot source evolves, with an increasing proportion of the radiation being emitted short-ward of the Lyman limit. The rate at which the spectrum evolves also depends on the speed class. We have therefore refined the simple model by assuming photons at energies higher than the Lyman limit are absorbed by neutral hydrogen gas internal to the dust formation sites, therefore preventing these photons reaching the nucleation sites. With this refinement the dust formation timescale is theoretically dependent on speed class and the results of our theoretical modification agree well with the observational data. We consider two types of carbon-based dust, graphite and amorphous carbon, with both types producing similar relationships. Our results can be used to predict when dust will form in a nova of a given speed class and hence when observations should optimally be taken to detect the onset of dust formation.

  14. Outgassing of icy bodies in the solar system - I. The sublimation of hexagonal water ice through dust layers

    E-Print Network [OSTI]

    Gundlach, Bastian; Blum, Jürgen

    2011-01-01

    Our knowledge about the physical processes determining the activity of comets were mainly influenced by several extremely successful space missions, the predictions of theoretical models and the results of laboratory experiments. However, novel computer models should not be treated in isolation but should be based on experimental results. Therefore, a new experimental setup was constructed to investigate the temperature dependent sublimation properties of hexagonal water ice and the gas diffusion through a dry dust layer covering the ice surface. We show that this experimental setup is capable to reproduce known gas production rates of pure hexagonal water ice. The reduction of the gas production rate due to an additional dust layer on top of the ice surface was measured and compared with the results of another experimental setup in which the gas diffusion through dust layers at room temperature was investigated. We found that the relative permeability of the dust layer is inversely proportional to its thickn...

  15. Will new horizons see dust clumps in the Edgeworth-Kuiper Belt?

    SciTech Connect (OSTI)

    Vitense, Christian; Krivov, Alexander V.; Löhne, Torsten

    2014-06-01

    Debris disks are thought to be sculptured by neighboring planets. The same is true for the Edgeworth-Kuiper debris disk, yet no direct observational evidence for signatures of giant planets in the Kuiper Belt dust distribution has been found so far. Here we model the dust distribution in the outer solar system to reproduce the dust impact rates onto the dust detector on board the New Horizons spacecraft measured so far and to predict the rates during the Neptune orbit traverse. To this end, we take a realistic distribution of trans-Neptunian objects to launch a sufficient number of dust grains of different sizes and follow their orbits by including radiation pressure, Poynting-Robertson and stellar wind drag, as well as the perturbations of four giant planets. In a subsequent statistical analysis, we calculate number densities and lifetimes of the dust grains in order to simulate a collisional cascade. In contrast to the previous work, our model not only considers collisional elimination of particles but also includes production of finer debris. We find that particles captured in the 3:2 resonance with Neptune build clumps that are not removed by collisions, because the depleting effect of collisions is counteracted by production of smaller fragments. Our model successfully reproduces the dust impact rates measured by New Horizons out to ?23 AU and predicts an increase of the impact rate of about a factor of two or three around the Neptune orbit crossing. This result is robust with respect to the variation of the vaguely known number of dust-producing scattered disk objects, collisional outcomes, and the dust properties.

  16. The Millennium Gas project aims to undertake smoothed-particle hydrodynamic resimulations of the Millennium Simulation, providing many hundred massive galaxy clusters for comparison with X-ray surveys (170 clusters with kTsl > 3 keV). This paper looks at

    E-Print Network [OSTI]

    Thomas, Peter

    . Abstract The Millennium Gas project aims to undertake smoothed-particle hydrodynamic-ray surveys (170 clusters with kTsl > 3 keV). This paper looks at the hot gas and stellar fractions-core systems but are successful in matching the hot gas profiles of non-cool-core clusters. Although

  17. Diffusion and stochastic heating of a dust cloud in tokamak edge plasmas

    SciTech Connect (OSTI)

    Marmolino, C. [Department STAT, University of Molise, Pesche (Italy); Bacharis, M.; Willis, C. [Imperial College, London SW7 2BW (United Kingdom); Allen, J. E. [Imperial College, London SW7 2BW (United Kingdom); OCIAM Mathematical Institute, Oxford OX1 3LB (United Kingdom); Angelis, U. de [Department of Physical Sciences, University of Naples and INFN Sezione di Napoli (Italy)

    2011-10-15

    The diffusion due to collisions with ions of a cloud of nano-meter dust particles in the region of the scrape-off-layer (SOL) of a tokamak is considered and it is shown that for the conditions in the Frascati tokamak upgrade, the cloud can expand to reach the SOL limit in very short times without ablating. The conditions for stochastic heating of the cloud and acceleration of a larger particle to hyper-velocities, taking into account the effect of decreasing dust density in the cloud, are established.

  18. 16 years of Ulysses Interstellar Dust Measurements in the Solar System: II. Fluctuations in the Dust Flow from the Data

    E-Print Network [OSTI]

    Strub, Peter; Sterken, Veerle J

    2015-01-01

    The Ulysses spacecraft provided the first opportunity to identify and study Interstellar Dust (ISD) in-situ in the Solar System between 1992 and 2007. Here we present the first comprehensive analysis of the ISD component in the entire Ulysses dust data set. We analysed several parameters of the ISD flow in a time-resolved fashion: flux, flow direction, mass index, and flow width. The general picture is in agreement with a time-dependent focussing/defocussing of the charged dust particles due to long-term variations of the solar magnetic field throughout a solar magnetic cycle of 22 years. In addition, we confirm a shift in dust direction of $50^{\\circ} \\pm 7^{\\circ}$ in 2005, along with a steep, size-dependent increase in flux by a factor of 4 within 8 months. To date, this is difficult to interpret and has to be examined in more detail by new dynamical simulations. This work is part of a series of three papers. This paper concentrates on the time-dependent flux and direction of the ISD. In a companion paper ...

  19. Secondary dust density waves excited by nonlinear dust acoustic waves J. R. Heinrich,1,a)

    E-Print Network [OSTI]

    Merlino, Robert L.

    Secondary dust density waves excited by nonlinear dust acoustic waves J. R. Heinrich,1,a) S.-H. Kim amplitude ðnd=nd0 > 2Þ dust acoustic waves (DAW) that were spontaneously excited in a dc glow discharge dusty plasma in the moderately coupled, C $ 1; state. The high amplitude dust acoustic waves produced

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

    E-Print Network [OSTI]

    Barkan, Christopher P.L.

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

  1. Dust Dynamics in Protoplanetary Disk Winds Driven by Magneto-Rotational Turbulence: A Mechanism for Floating Dust Grains with Characteristic Size

    E-Print Network [OSTI]

    Miyake, Tomoya; Inutsuka, Shu-ichiro

    2015-01-01

    We investigate the dynamics of dust grains with various sizes in protoplanetary disk winds driven by magnetorotational turbulence, by simulating the time evolution of the dust grain distribution in the vertical direction. Small dust grains, which are well coupled to the gas, are dragged upward with the upflowing gas, while large grains remain near the midplane of a disk. Intermediate--size grains float at several scale heights from the midplane in time-averated force balance between the downward gravity and the upward gas drag. For the minimum mass solar nebula at 1 AU, dust grains with size of 20 -- 40 $\\mu m$ float at 5-10 scale heights from the midplane. Considering the dependence on the distance from the central star, smaller-size grains remain only in an outer region of the disk, while larger-size grains are distributed in a broader region. This implies that the dust depletion is expected to take place in small-to-large and inside-out manners. We also discuss the implication of our result to the observat...

  2. Adding coal dust to coal batch

    SciTech Connect (OSTI)

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

    2009-05-15

    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.

  3. Signatures of recent asteroid disruptions in the formation and evolution of solar system dust bands

    E-Print Network [OSTI]

    Kehoe, A J Espy; Colwell, J E; Dermott, S F

    2015-01-01

    We have performed detailed dynamical modeling of the structure of a faint dust band observed in coadded IRAS data at an ecliptic latitude of 17$^{\\circ}$ that convincingly demonstrates that it is the result of a relatively recent (significantly less than 1 Ma) disruption of an asteroid and is still in the process of forming. We show here that young dust bands retain information on the size distribution and cross-sectional area of dust released in the original asteroid disruption, before it is lost to orbital and collisional decay. We find that the Emilkowalski cluster is the source of this partial band and that the dust released in the disruption would correspond to a regolith layer $\\sim$3 m deep on the $\\sim$10 km diameter source body's surface. The dust in this band is described by a cumulative size-distribution inverse power-law index with a lower bound of 2.1 (implying domination of cross-sectional area by small particles) for dust particles with diameters ranging from a few $\\mu$m up to a few cm. The co...

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

    E-Print Network [OSTI]

    Markus Landgraf; Michael Müller; Eberhard Grün

    1999-04-15

    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.

  5. 205:20130828.1126 Dust Accelerator Laboratory

    E-Print Network [OSTI]

    Mojzsis, Stephen J.

    205:20130828.1126 Dust Accelerator Laboratory Through the Dust Accelerator Laboratory, LASP, and laboratory experiments. Our goal is to address basic physical and applied exploration questions, including Laboratory is home to world-class facilities, including the largest dust accelerator in the world

  6. Dust transport: Wind blown and mechanical resuspension, July 1983 to December 1984

    SciTech Connect (OSTI)

    Langer, G.

    1986-09-20

    This study defines the processes that resuspend plutonium (Pu) particles from Pu-contaminated soil at Rocky Flats. Such knowledge can predict the transport of Pu particles from the site and the population dose. A vertical dust flux tower profiled the plume of Pu particles from the site. The data show a 70% reduction between 1 and 10 m in the concentration of coarse and inhalable Pu particles. The respirable particle concentration remained steady at both heights, slightly above background levels. High winds visually resuspend large amounts of dust for short periods, but we suspected that present sampling devices do not function properly above 50 km/h. During a windstorm reaching 80 km/h, the size-selective sampler used seriously underestimated the dust(Pu) concentration. Wind tunnel studies measured resuspension versus wind speed from our prairie grass covered, arid soil. We failed to find a good correlation between resuspension and wind speed. This led to a search for alternative mechanisms of resuspension besides wind erosion. Resuspension of dust(Pu) from grass proved to be important, as well as resuspension from rain splash.

  7. ALMA imaging of gas and dust in a galaxy protocluster at redshift 5.3: [C II] emission in 'typical' galaxies and dusty starbursts ?1 billion years after the big bang

    SciTech Connect (OSTI)

    Riechers, Dominik A.; Carilli, Christopher L.; Capak, Peter L.; Yan, Lin; Scoville, Nicholas Z.; Smol?i?, Vernesa; Schinnerer, Eva; Yun, Min; Cox, Pierre; Bertoldi, Frank; Karim, Alexander

    2014-12-01

    We report interferometric imaging of [C II]({sup 2} P {sub 3/2}?{sup 2} P {sub 1/2}) and OH({sup 2}?{sub 1/2} J = 3/2?1/2) emission toward the center of the galaxy protocluster associated with the z = 5.3 submillimeter galaxy (SMG) AzTEC-3, using the Atacama Large (sub)Millimeter Array (ALMA). We detect strong [C II], OH, and rest-frame 157.7 ?m continuum emission toward the SMG. The [C II]({sup 2} P {sub 3/2}?{sup 2} P {sub 1/2}) emission is distributed over a scale of 3.9 kpc, implying a dynamical mass of 9.7 × 10{sup 10} M {sub ?}, and a star formation rate (SFR) surface density of ?{sub SFR} = 530 M {sub ?} yr{sup –1} kpc{sup –2}. This suggests that AzTEC-3 forms stars at ?{sub SFR} approaching the Eddington limit for radiation pressure supported disks. We find that the OH emission is slightly blueshifted relative to the [C II] line, which may indicate a molecular outflow associated with the peak phase of the starburst. We also detect and dynamically resolve [C II]({sup 2} P {sub 3/2}?{sup 2} P {sub 1/2}) emission over a scale of 7.5 kpc toward a triplet of Lyman-break galaxies with moderate UV-based SFRs in the protocluster at ?95 kpc projected distance from the SMG. These galaxies are not detected in the continuum, suggesting far-infrared SFRs of <18-54 M {sub ?} yr{sup –1}, consistent with a UV-based estimate of 22 M {sub ?} yr{sup –1}. The spectral energy distribution of these galaxies is inconsistent with nearby spiral and starburst galaxies, but resembles those of dwarf galaxies. This is consistent with expectations for young starbursts without significant older stellar populations. This suggests that these galaxies are significantly metal-enriched, but not heavily dust-obscured, 'normal' star-forming galaxies at z > 5, showing that ALMA can detect the interstellar medium in 'typical' galaxies in the very early universe.

  8. Effect of confining wall potential on charged collimated dust beam in low-pressure plasma

    SciTech Connect (OSTI)

    Kausik, S. S.; Kakati, B.; Saikia, B. K. [Centre of Plasma Physics, Institute for Plasma Research, Sonapur 782 402 (India)] [Centre of Plasma Physics, Institute for Plasma Research, Sonapur 782 402 (India)

    2013-05-15

    The effect of confining wall potential on charged collimated dust beam in low-pressure plasma has been studied in a dusty plasma experimental setup by applying electrostatic field to each channel of a multicusp magnetic cage. Argon plasma is produced by hot cathode discharge method at a pressure of 5×10{sup ?4} millibars and is confined by a full line cusped magnetic field confinement system. Silver dust grains are produced by gas-evaporation technique and move upward in the form of a collimated dust beam due to differential pressure maintained between the dust and plasma chambers. The charged grains in the beam after coming out from the plasma column enter into the diagnostic chamber and are deflected by a dc field applied across a pair of deflector plates at different confining potentials. Both from the amount of deflection and the floating potential, the number of charges collected by the dust grains is calculated. Furthermore, the collimated dust beam strikes the Faraday cup, which is placed above the deflector plates, and the current (?pA) so produced is measured by an electrometer at different confining potentials. The experimental results demonstrate the significant effect of confining wall potential on charging of dust grains.

  9. NGC 7538 IRS. 1. Interaction of a polarized dust spiral and a molecular outflow

    SciTech Connect (OSTI)

    Wright, M. C. H.; Hull, Charles L. H. [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Pillai, Thushara [Max Planck Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Zhao, Jun-Hui [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Sandell, Göran, E-mail: jzhao@cfa.harvard.edu [SOFIA-USRA, NASA Ames Research Center, MS 232-12, Building N232, Room 146, PO Box 1, Moffett Field, CA 94035-0001 (United States)

    2014-12-01

    We present dust polarization and CO molecular line images of NGC 7538 IRS 1. We combined data from the Submillimeter Array, the Combined Array for Research in Millimeter-wave Astronomy, and the James Clerk Maxwell Telescope to make images with ?2.''5 resolution at 230 and 345 GHz. The images show a remarkable spiral pattern in both the dust polarization and molecular outflow. These data dramatically illustrate the interplay between a high infall rate onto IRS 1 and a powerful outflow disrupting the dense, clumpy medium surrounding the star. The images of the dust polarization and the CO outflow presented here provide observational evidence for the exchange of energy and angular momentum between the infall and the outflow. The spiral dust pattern, which rotates through over 180° from IRS 1, may be a clumpy filament wound up by conservation of angular momentum in the infalling material. The redshifted CO emission ridge traces the dust spiral closely through the MM dust cores, several of which may contain protostars. We propose that the CO maps the boundary layer where the outflow is ablating gas from the dense gas in the spiral.

  10. Impacts of Imported Liquefied Natural Gas on Residential Appliance Components: Literature Review

    E-Print Network [OSTI]

    Lekov, Alex

    2010-01-01

    exchangers are used on gas and oil units. In the last 15floor-level lint, dust, and oil, and a flame arrestor with

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

    E-Print Network [OSTI]

    Nittler, Larry R.

    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

  12. 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

  13. Naked singularity explosion in higher-dimensional dust collapse

    E-Print Network [OSTI]

    Masahiro Shimano; Umpei Miyamoto

    2013-12-20

    In the context of the large extra dimensions or TeV-scale gravity, it has been argued that an effective naked singularity, called the visible border of spacetime, would be generated by high-energy particle collisions. Motivated by this interesting possibility, we investigate a particle creation by a naked singularity in general dimensions, adopting a spherically symmetric self-similar dust collapse as the simple model of a naked singularity formation. The power and energy of the particle emission behave in two distinct ways depending on a parameter in the model. In a generic case, the emission power is proportional to the quadratic inverse of the remaining time to the Cauchy horizon, which has been known for the four-dimensional case in the literature. On the other hand, in a degenerate case the emission power is proportional to the quartic inverse of the remaining time to the Cauchy horizon, and depends on the total mass of a dust fluid in spite that the central region of the collapse is scale-free due to the self-similarity. In the both cases, within a test-field approximation the energy radiated before any quantum gravitational effect dominates amounts to TeV. This suggests that a backreaction is not ignorable in the TeV-scale gravity context, in contrast to the similar phenomena in stellar collapse.

  14. Dust dynamics and evolution in expanding HII regions. I. Radiative drift of neutral and charged grains

    E-Print Network [OSTI]

    Akimkin, V V; Pavlyuchenkov, Ya N; Wiebe, D S

    2015-01-01

    We consider dust drift under the influence of stellar radiation pressure during the pressure-driven expansion of an HII region using the chemo-dynamical model MARION. Dust size distribution is represented by four dust types: conventional polycyclic aromatic hydrocarbons (PAHs), very small grains (VSGs), big grains (BGs) and also intermediate-sized grains (ISGs), which are larger than VSGs and smaller than BGs. The dust is assumed to move at terminal velocity determined locally from the balance between the radiation pressure and gas drag. As Coulomb drag is an important contribution to the overall gas drag, we evaluate a grain charge evolution within the HII region for each dust type. BGs are effectively swept out of the HII region. The spatial distribution of ISGs within the HII region has a double peak structure, with a smaller inner peak and a higher outer peak. PAHs and VSGs are mostly coupled to the gas. The mean charge of PAHs is close to zero, so they can become neutral from time to time because of char...

  15. Method of producing carbon coated nano- and micron-scale particles

    DOE Patents [OSTI]

    Perry, W. Lee; Weigle, John C; Phillips, Jonathan

    2013-12-17

    A method of making carbon-coated nano- or micron-scale particles comprising entraining particles in an aerosol gas, providing a carbon-containing gas, providing a plasma gas, mixing the aerosol gas, the carbon-containing gas, and the plasma gas proximate a torch, bombarding the mixed gases with microwaves, and collecting resulting carbon-coated nano- or micron-scale particles.

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

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

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

    2015-05-19

    The mineral dust cycle responds to climate variations and plays an important role in the climate system by affecting the radiative balance of the atmosphere and modifying biogeochemistry. Polar ice cores provide unique information about deposition of aeolian dust particles transported over long distances. These cores are a palaeoclimate proxy archive of climate variability thousands of years ago. The current study is a first attempt to simulate past interglacial dust cycles with a global aerosol–climate model ECHAM5-HAM. The results are used to explain the dust deposition changes in Antarctica in terms of quantitative contribution of different processes, such as emission,more »atmospheric transport and precipitation, which will help to interpret palaeodata from Antarctic ice cores. The investigated periods include four interglacial time slices: the pre-industrial control (CTRL), mid-Holocene (6000 yr BP; hereafter referred to as \\"6 kyr\\"), last glacial inception (115 000 yr BP; hereafter \\"115 kyr\\") and Eemian (126 000 yr BP; hereafter \\"126 kyr\\"). One glacial time interval, the Last Glacial Maximum (LGM) (21 000 yr BP; hereafter \\"21 kyr\\"), was simulated as well to be a reference test for the model. Results suggest an increase in mineral dust deposition globally, and in Antarctica, in the past interglacial periods relative to the pre-industrial CTRL simulation. Approximately two-thirds of the increase in the mid-Holocene and Eemian is attributed to enhanced Southern Hemisphere dust emissions. Slightly strengthened transport efficiency causes the remaining one-third of the increase in dust deposition. The moderate change in dust deposition in Antarctica in the last glacial inception period is caused by the slightly stronger poleward atmospheric transport efficiency compared to the pre-industrial. Maximum dust deposition in Antarctica was simulated for the glacial period. LGM dust deposition in Antarctica is substantially increased due to 2.6 times higher Southern Hemisphere dust emissions, 2 times stronger atmospheric transport towards Antarctica, and 30% weaker precipitation over the Southern Ocean. The model is able to reproduce the order of magnitude of dust deposition globally and in Antarctica for the pre-industrial and LGM climates.« less

  17. Twelve thousand years of dust: the Holocene global dust cycle constrained by natural archives

    E-Print Network [OSTI]

    Albani, S.

    Mineral dust plays an important role in the climate system by interacting with radiation, clouds, and biogeochemical cycles. In addition, natural archives show that the dust cycle experienced variability in the past in ...

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

    E-Print Network [OSTI]

    Newman, David

    Mineral Dust Entrainment and Deposition (DEAD) model: Description and 1990s dust climatology to 1999 is simulated with our mineral aerosol entrainment and deposition module embedded in a chemical transport model. Mobilization processes include entrainment thresholds for saltation, moisture inhibition

  19. Anisotropic collective flow of a Lorentz gas

    E-Print Network [OSTI]

    Nicolas Borghini; Clement Gombeaud

    2011-06-30

    Analytical results for the anisotropic collective flow of a Lorentz gas of massless particles scattering on fixed centres are presented.

  20. Dust-acoustic filamentation of a current-driven dusty plasma

    SciTech Connect (OSTI)

    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)

    2011-06-15

    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.

  1. Inhomogeneous cloud coverage through the Coulomb explosion of dust in substellar atmospheres

    E-Print Network [OSTI]

    Stark, Craig R; Diver, Declan A

    2015-01-01

    Recent observations of brown dwarf spectroscopic variability in the infrared infer the presence of patchy cloud cover. This paper proposes a mechanism for producing inhomogeneous cloud coverage due to the depletion of cloud particles through the Coulomb explosion of dust in atmospheric plasma regions. Charged dust grains Coulomb-explode when the electrostatic stress of the grain exceeds its mechanical tensile stress, which results in grains below a critical radius $aeV ($\\approx10^{5}$~K), the critical grain radius varies from $10^{-7}$ to $10^{-4}$~cm, depending on the grains' tensile strength. Higher critical radii up to $10^{-3}$~cm ...

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

    E-Print Network [OSTI]

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

    2013-01-01

    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 ...

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

    E-Print Network [OSTI]

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

    2013-01-24

    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.

  4. THE DUST ENVIRONMENT OF MAIN-BELT COMET P/2012 T1 (PANSTARRS)

    SciTech Connect (OSTI)

    Moreno, F.; Pozuelos, F. [Instituto de Astrofisica de Andalucia, CSIC, Glorieta de la Astronomia s/n, E-18008 Granada (Spain); Cabrera-Lavers, A.; Vaduvescu, O.; Licandro, J., E-mail: fernando@iaa.es [Instituto de Astrofisica de Canarias, c/Via Lactea s/n, E-38200 La Laguna, Tenerife (Spain)

    2013-06-20

    The Main-Belt Comet P/2012 T1 (PANSTARRS) has been imaged using the 10.4 m Gran Telescopio Canarias and the 4.2 m William Herschel Telescope at six epochs in the period from 2012 November to 2013 February, with the aim of monitoring its dust environment. The dust tails' brightness and morphology are best interpreted in terms of a model of sustained dust emission spanning four to six months. The total dust mass ejected is estimated at {approx}6-25 Multiplication-Sign 10{sup 6} kg. We assume a time-independent power-law size distribution function, with particles in the micrometer to centimeter size range. Based on the quality of the fits to the isophote fields, an anisotropic emission pattern is favored against an isotropic one, in which the particle ejection is concentrated toward high latitudes ({+-}45 Degree-Sign to {+-}90 Degree-Sign ) in a high-obliquity object (I = 80 Degree-Sign ). This seasonally driven ejection behavior, along with the modeled particle ejection velocities, are in remarkable agreement to those we found for P/2010 R2 (La Sagra).

  5. Dust Defeats Germ-Killing Fabrics | Jefferson Lab

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

    Kelley speculates that dust protected germs from the fabrics' germ-killing surface. "Microbes grow on the dust. And now, because you have all this dust on the fabric, instead of...

  6. Coated Particle Fuel Development Lab (CPFDL) | ORNL

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

    TRISO Coating 50 mm Fluidized Bed Chemical Vapor Deposition System Computer control of coating temperature and gas composition Particle Classification Tabler, roller micrometer,...

  7. Rigidly rotating cylinders of charged dust

    E-Print Network [OSTI]

    B. V. Ivanov

    2002-07-02

    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.

  8. Global dust model intercomparison in AeroCom phase I

    E-Print Network [OSTI]

    2011-01-01

    Atlantic as recorded in both Barbados surface concentrationsmarine boundary layer at Barbados: Impact of African dust,on Mineral Dust in the Barbados Trade Winds, Nature, 320(

  9. Dust Emission from the Perseus Molecular Cloud

    E-Print Network [OSTI]

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

    2008-05-27

    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.

  10. Performance of Supply Airflow Entrainment for Particles in an Underfloor Air Distribution System 

    E-Print Network [OSTI]

    Li, C.; Li, N.

    2006-01-01

    model is established. Comparison of the numerical calculation results of the airflow field with the measured data is given. Results show that the model is valid and can predict the performance of airflow entrainment for dust particles in different air...

  11. Outgassing of icy bodies in the Solar System - II. Heat transport in dry, porous surface dust layers

    E-Print Network [OSTI]

    Gundlach, Bastian

    2011-01-01

    In this work, we present a new model for the heat conductivity of porous dust layers in vacuum, based on an existing solution of the heat transfer equation of single spheres in contact. This model is capable to distinguish between two different types of dust layers: dust layers composed of single particles (simple model) and dust layers consisting of individual aggregates (complex model). Additionally, we describe laboratory experiments, which were used to measure the heat conductivity of porous dust layers, in order to test the model. We found that the model predictions are in an excellent agreement with the experimental results. Furthermore, the implications of this new model on the modeling of cometary activity are discussed. Finally, the two variants of the model are used to calculate the H2O ice outgassing rate of comets as a function of the thickness of the ice-free dust layer. Therewith, the pressure inside the dust layer is derived and compared with the tensile strength of the material in order to dis...

  12. Particle generator

    DOE Patents [OSTI]

    Hess, Wayne P.; Joly, Alan G.; Gerrity, Daniel P.; Beck, Kenneth M.; Sushko, Peter V.; Shlyuger, Alexander L.

    2005-06-28

    Energy tunable solid state sources of neutral particles are described. In a disclosed embodiment, a halogen particle source includes a solid halide sample, a photon source positioned to deliver photons to a surface of the halide, and a collimating means positioned to accept a spatially defined plume of hyperthermal halogen particles emitted from the sample surface.

  13. Coal Fly Ash as a Source of Iron in Atmospheric Dust

    SciTech Connect (OSTI)

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

    2012-01-18

    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.

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

    E-Print Network [OSTI]

    Merlino, Robert L.

    Dust-Acoustic Waves: Visible Sound Waves Robert L. Merlino Department of Physics and Astronomy and experimental work on dust acoustic waves is given. The basic physics of the dust acoustic wave and some findings and outstanding problems are also presented. Keywords: dusty plasmas, dust acoustic waves PACS: 52

  15. Method and apparatus for cutting and abrading with sublimable particles

    DOE Patents [OSTI]

    Bingham, D.N.

    1995-10-10

    A gas delivery system provides a first gas as a liquid under extreme pressure and as a gas under intermediate pressure. Another gas delivery system provides a second gas under moderate pressure. The second gas is selected to solidify at a temperature at or above the temperature of the liquefied gas. A nozzle assembly connected to the gas delivery systems produces a stream containing a liquid component, a solid component, and a gas component. The liquid component of the stream consists of a high velocity jet of the liquefied first gas. The high velocity jet is surrounded by a particle sheath that consists of solid particles of the second gas which solidifies in the nozzle upon contact with the liquefied gas of the high velocity jet. The gas component of the stream is a high velocity flow of the first gas that encircles the particle sheath, forming an outer jacket. 6 figs.

  16. Method and apparatus for cutting and abrading with sublimable particles

    DOE Patents [OSTI]

    Bingham, Dennis N. (Idaho Falls, ID)

    1995-01-01

    A gas delivery system provides a first gas as a liquid under extreme pressure and as a gas under intermediate pressure. Another gas delivery system provides a second gas under moderate pressure. The second gas is selected to solidify at a temperature at or above the temperature of the liquified gas. A nozzle assembly connected to the gas delivery systems produces a stream containing a liquid component, a solid component, and a gas component. The liquid component of the stream consists of a high velocity jet of the liquified first gas. The high velocity jet is surrounded by a particle sheath that consists of solid particles of the second gas which solidifies in the nozzle upon contact with the liquified gas of the high velocity jet. The gas component of the stream is a high velocity flow of the first gas that encircles the particle sheath, forming an outer jacket.

  17. Preparation and characterization of palladium particles

    SciTech Connect (OSTI)

    Silver, G.L.; Leahy, B.T.; Martin, F.S.

    1989-02-15

    Palladium particles were prepared by burning palladium loaded ion exchange resins and reducing the combustion products with hydrogen gas. The particles can be compressed into pellets. Properties of the pellets, such as resistance to the flow of hydrogen gas and rate of exchange with deuterium, have been measured. 2 refs., 16 figs., 17 tabs.

  18. Shock-Wave Heating Model for Chondrule Formation: Hydrodynamic Simulation of Molten Droplets exposed to Gas Flows

    E-Print Network [OSTI]

    Miura, H; Miura, Hitoshi; Nakamoto, Taishi

    2006-01-01

    Millimeter-sized, spherical silicate grains abundant in chondritic meteorites, which are called as chondrules, are considered to be a strong evidence of the melting event of the dust particles in the protoplanetary disk. One of the most plausible scenarios is that the chondrule precursor dust particles are heated and melt in the high-velocity gas flow (shock-wave heating model). We developed the non-linear, time-dependent, and three-dimensional hydrodynamic simulation code for analyzing the dynamics of molten droplets exposed to the gas flow. We confirmed that our simulation results showed a good agreement in a linear regime with the linear solution analytically derived by Sekiya et al. (2003). We found that the non-linear terms in the hydrodynamical equations neglected by Sekiya et al. (2003) can cause the cavitation by producing negative pressure in the droplets. We discussed that the fragmentation through the cavitation is a new mechanism to determine the upper limit of chondrule sizes. We also succeeded t...

  19. Surface acoustic wave dust deposition monitor

    DOE Patents [OSTI]

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

    1988-02-12

    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.

  20. Global coherence of dust density waves

    SciTech Connect (OSTI)

    Killer, Carsten; Melzer, André

    2014-06-15

    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.

  1. FRAGMENTATION AND EVOLUTION OF MOLECULAR CLOUDS. II. THE EFFECT OF DUST HEATING

    SciTech Connect (OSTI)

    Urban, Andrea; Evans, Neal J. [Department of Astronomy, University of Texas, Austin, TX 78712 (United States); Martel, Hugo [Departement de Physique, genie physique et optique, Universite Laval, Quebec, QC G1K 7P4 (Canada)

    2010-02-20

    We investigate the effect of heating by luminosity sources in a simulation of clustered star formation. Our heating method involves a simplified continuum radiative transfer method that calculates the dust temperature. The gas temperature is set by the dust temperature. We present the results of four simulations; two simulations assume an isothermal equation of state and the two other simulations include dust heating. We investigate two mass regimes, i.e., 84 M{sub sun} and 671 M{sub sun}, using these two different energetics algorithms. The mass functions for the isothermal simulations and simulations that include dust heating are drastically different. In the isothermal simulation, we do not form any objects with masses above 1 M{sub sun}. However, the simulation with dust heating, while missing some of the low-mass objects, forms high-mass objects ({approx}20 M{sub sun}) which have a distribution similar to the Salpeter initial mass function. The envelope density profiles around the stars formed in our simulation match observed values around isolated, low-mass star-forming cores. We find the accretion rates to be highly variable and, on average, increasing with final stellar mass. By including radiative feedback from stars in a cluster-scale simulation, we have determined that it is a very important effect which drastically affects the mass function and yields important insights into the formation of massive stars.

  2. Index of refraction of gases for matter waves: effect of the motion of the gas particles on the calculation of the index

    E-Print Network [OSTI]

    Caroline Champenois; Marion Jacquey; Steven Lepoutre; Matthias Büchner; Gérard Trénec; Jacques Vigué

    2007-11-09

    Two different formulae relating the index of refraction $n$ of gases for atom waves to the scattering amplitude have been published. We show here that these two formulae are not consistent with the definition of the total scattering cross-section while the formula developed by one of us (C.C.) in her thesis is in agreement with this standard knowledge. We discuss this result, in particular in the neutron case for which such an index was first introduced. We finally evaluate the index of refraction as a function of well known quantities and we discuss the order of magnitude of the ratio of $(n-1)/n_t$, where $n_t$ is the gas density.

  3. Tables of phase functions, opacities, albedos, equilibrium temperatures, and radiative accelerations of dust grains in exoplanets

    E-Print Network [OSTI]

    Budaj, Jan; Salmeron, Raquel; Hubeny, Ivan

    2015-01-01

    There has been growing observational evidence for the presence of condensates in the atmospheres and/or comet-like tails of extrasolar planets. As a result, systematic and homogeneous tables of dust properties are useful in order to facilitate further observational and theoretical studies. In this paper we present calculations and analysis of non-isotropic phase functions, asymmetry parameter (mean cosine of the scattering angle), absorption and scattering opacities, single scattering albedos, equilibrium temperatures, and radiative accelerations of dust grains relevant for extrasolar planets. Our assumptions include spherical grain shape, Deirmendjian particle size distribution, and Mie theory. We consider several species: corundum/alumina, iron, olivines with 0% and 50% iron content, pyroxenes with 0%, 20% and 60% iron content, carbon at two different temperatures, water ice, liquid water, and ammonia. The presented tables cover the wavelength range of 0.2 to 500 micron and modal particle radii from 0.01 mi...

  4. Measurement of Fine Particles From Mobile and Stationary Sources, and Reducing the Air Conditioner Power Consumption in Hybrid Electric Vehicles

    E-Print Network [OSTI]

    Brewer, Eli Henry

    2015-01-01

    Bengtsson K. , 2002, “Gas Turbines – Sources or Sinks forParticle Emissions from Gas Turbines, Technical reportGrowth from Natural Gas Turbines. ,” Prep. [31] Lobo P. ,

  5. Quantitative organic vapor-particle sampler

    DOE Patents [OSTI]

    Gundel, Lara (Berkeley, CA); Daisey, Joan M. (Walnut Creek, CA); Stevens, Robert K. (Cary, NC)

    1998-01-01

    A quantitative organic vapor-particle sampler for sampling semi-volatile organic gases and particulate components. A semi-volatile organic reversible gas sorbent macroreticular resin agglomerates of randomly packed microspheres with the continuous porous structure of particles ranging in size between 0.05-10 .mu.m for use in an integrated diffusion vapor-particle sampler.

  6. Spectral solar irradiance before and during a Harmattan dust spell

    SciTech Connect (OSTI)

    Adeyefa, Z.D. [Federal Univ. of Technology, Akure (Nigeria)] [Federal Univ. of Technology, Akure (Nigeria); Holmgren, B. [Uppsala Univ. (Sweden)] [Uppsala Univ. (Sweden)

    1996-09-01

    Measurements of the ground-level spectral distributions of the direct, diffuse and global solar irradiance between 300 and 1100 nm were made at Akure (7.15{degree}N, 5.5{degree}E), Nigeria, in December 1991 before and during a Harmattan dust spell employing a spectroradiometer (LICOR LI-1800) with 6 nm resolution. The direct spectral solar irradiance which was initially reduced before the dust storm was further attenuated by about 50% after the spell. Estimated values of the Angstrom turbidity coefficient {beta} indicated an increase of about 146% of this parameter while the Angstrom wavelength-exponent {alpha} decreased by about 65% within the 2-day study period. The spectral diffuse-to-direct and diffuse-to-global ratios suggest that the main cause of the significant reduction in solar irradiance at the surface was the scattering by the aerosol which led to an increase in the diffuse component. The global irradiance though reduced, was less sensitive to changing Harmattan conditions. It is recommended that solar energy devices that use radiation from Sun and sky be used under fluctuating Harmattan conditions. There are some deviations from the Angstrom formula under very turbid Harmattan conditions which could be explained by the relative increase of the particle sizes. 31 refs., 12 figs., 3 tabs.

  7. Moment equations for chemical reactions on interstellar dust grains

    E-Print Network [OSTI]

    Azi Lipshtat; Ofer Biham

    2002-12-09

    While most chemical reactions in the interstellar medium take place in the gas phase, those occurring on the surfaces of dust grains play an essential role. Chemical models based on rate equations including both gas phase and grain surface reactions have been used in order to simulate the formation of chemical complexity in interstellar clouds. For reactions in the gas phase and on large grains, rate equations, which are highly efficient to simulate, are an ideal tool. However, for small grains under low flux, the typical number of atoms or molecules of certain reactive species on a grain may go down to order one or less. In this case the discrete nature of the opulations of reactive species as well as the fluctuations become dominant, thus the mean-field approximation on which the rate equations are based does not apply. Recently, a master equation approach, that provides a good description of chemical reactions on interstellar dust grains, was proposed. Here we present a related approach based on moment equations that can be obtained from the master equation. These equations describe the time evolution of the moments of the distribution of the population of the various chemical species on the grain. An advantage of this approach is the fact that the production rates of molecular species are expressed directly in terms of these moments. Here we use the moment equations to calculate the rate of molecular hydrogen formation on small grains. It is shown that the moment equation approach is efficient in this case in which only a single reactive specie is involved. The set of equations for the case of two species is presented and the difficulties in implementing this approach for complex reaction networks involving multiple species are discussed.

  8. The Relationship between CO Emission and Visual Extinction Traced by Dust Emission in the Magellanic Clouds

    E-Print Network [OSTI]

    Lee, Cheoljong; Schnee, Scott; Wong, Tony; Bolatto, Alberto D; Indebetouw, Remy; Rubio, Monica

    2015-01-01

    To test the theoretical understanding that finding bright CO emission depends primarily on dust shielding, we investigate the relationship between CO emission ($I_{\\rm CO}$) and the amount of dust (estimated from IR emission and expressed as "$A_V$") across the Large Magellanic Cloud, the Small Magellanic Cloud, and the Milky Way. We show that at our common resolution of 10 pc scales, $I_{\\rm CO}$ given a fixed line-of-sight $A_V$ is similar across all three systems despite the difference in metallicity. We find some evidence for a secondary dependence of $I_{\\rm CO}$ on radiation field; in the LMC, $I_{\\rm CO}$ at a given $A_V$ is smaller in regions of high $T_{\\rm dust}$, perhaps because of an increased photodissociating radiation field. We suggest a simple but useful picture in which the CO-to-H$_2$ conversion factor (\\xco) depends on two separable factors: (1) the distribution of gas column densities, which maps to an extinction distribution via a dust-to-gas ratio; and (2) the dependence of $I_{\\rm CO}$ ...

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

    SciTech Connect (OSTI)

    Schraepler, Rainer; Blum, Juergen; Seizinger, Alexander; Kley, Wilhelm

    2012-10-10

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

  10. Investigation of techniques to improve continuous air monitors under conditions of high dust loading in environmental setting. 1998 annual progress report

    SciTech Connect (OSTI)

    Schery, S.D.; Wasiolek, P.T. [New Mexico Inst. of Mining and Technology, Socorro, NM (US); Rodgers, J. [Los Alamos National Lab., NM (US)

    1998-06-01

    'Improvement in understanding of the deposition of ambient dust particles on ECAM (Environmental Continuous Air Monitor) filters, reduction of the alpha-particle interference of radon progeny and other radioactive aerosols in different particle size ranges on filters, and development of ECAM''s with increased sensitivity under dusty outdoor conditions. As of May 1, 1998 (1/2 year into the project) the research-prototype 30-cm pulsed ionization chamber (PIC) is assembled and operational with an alpha particle energy resolution of better than 45 keV for 5-MeV alpha particles. Measurements of spectral resolution for alpha particles from radon decay products have been made as a function of filter type and dust loading conditions. So far, a study of ten filter types has found that the best combination of resolution and throughput is obtained with 3.0 \\265m Millipore fluoropore and 1.0 \\265m Corning FNMB filters. Experiments with gypsum and Portland cement dust in the size range 1 to 20 \\265m indicate significant degradation in alpha particle resolution for dust loading above about 0.5 mg cm{sup -2}. Study of metalized films for possible use as a PIC window indicate a minimum broadening of 5-MeV alpha particle peaks from 43 (no film) to 301 keV (with film) for AVR film type B8 (0.20 mg cm{sup -2} polycarbonate). A modified ECAM sampling head, equipped with an optical microscopy system feeding data to a high resolution video data capture and logging instrument, was constructed. This system will enable time-lapse study of dust build-up on ECAM filters and formation of dendrite structures that can reduce alpha-particle resolution.'

  11. A NEW SOLAR THERMAL RECEIVER UTILIZING A SMALL PARTICLE HEAT EXCHANGER

    E-Print Network [OSTI]

    Hunt, Arlon J.

    2011-01-01

    a Small Particle Heat Exchange Receiver (SPHER) operates byof the Small Particle Heat Exchange Receiver (or SPHER), asabsorption process, the heat exchange to the gas, the their

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

    E-Print Network [OSTI]

    Smith, Nathan; Filippenko, Alexei V

    2007-01-01

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

  13. Cold condensation of dust in the ISM

    E-Print Network [OSTI]

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

    2015-01-01

    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...

  14. Dust ion-acoustic rogue waves in a three-species ultracold quantum dusty plasmas

    SciTech Connect (OSTI)

    Sun, Wen-Rong; Tian, Bo Liu, Rong-Xiang; Liu, De-Yin

    2014-10-15

    Dust ion-acoustic (DIA) rogue waves are reported for a three-component ultracold quantum dusty plasma comprised of inertialess electrons, inertial ions, and negatively charged immobile dust particles. The nonlinear Schrödinger (NLS) equation appears for the low frequency limit. Modulation instability (MI) of the DIA waves is analyzed. Influence of the modulation wave number, ion-to-electron Fermi temperature ratio ? and dust-to-ion background density ratio N{sub d} on the MI growth rate is discussed. The first- and second-order DIA rogue-wave solutions of the NLS equation are examined numerically. It is found that the enhancement of N{sub d} and carrier wave number can increase the envelope rogue-wave amplitudes. However, the increase of ? reduces the envelope rogue-wave amplitudes. - Highlights: • The nonlinear Schrödinger equation is derived for the low frequency limit. • Modulational instability growth rate is discussed. • The first- and second-order dust ion-acoustic rogue waves are examined numerically.

  15. Oil shale retorting with steam and produced gas

    SciTech Connect (OSTI)

    Merrill, L.S. Jr.; Wheaton, L.D.

    1991-08-20

    This patent describes a process for retorting oil shale in a vertical retort. It comprises introducing particles of oil shale into the retort, the particles of oil shale having a minimum size such that the particles are retained on a screen having openings 1/4 inch in size; contacting the particles of oil shale with hot gas to heat the particles of oil shale to a state of pyrolysis, thereby producing retort off-gas; removing the off-gas from the retort; cooling the off-gas; removing oil from the cooled off-gas; separating recycle gas from the off-gas, the recycle gas comprising steam and produced gas, the steam being present in amount, by volume, of at least 50% of the recycle gas so as to increase the yield of sand oil; and heating the recycle gas to form the hot gas.

  16. AEROSOL PARTICLE COLLECTOR DESIGN STUDY

    SciTech Connect (OSTI)

    Lee, S; Richard Dimenna, R

    2007-09-27

    A computational evaluation of a particle collector design was performed to evaluate the behavior of aerosol particles in a fast flowing gas stream. The objective of the work was to improve the collection efficiency of the device while maintaining a minimum specified air throughput, nominal collector size, and minimal power requirements. The impact of a range of parameters was considered subject to constraints on gas flow rate, overall collector dimensions, and power limitations. Potential improvements were identified, some of which have already been implemented. Other more complex changes were identified and are described here for further consideration. In addition, fruitful areas for further study are proposed.

  17. Review of Particle Physics

    E-Print Network [OSTI]

    Nakamura, Kenzo

    2010-01-01

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

  18. REVIEW OF PARTICLE PHYSICS

    E-Print Network [OSTI]

    Beringer, Juerg

    2013-01-01

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

  19. Real-time airborne particle analyzer

    DOE Patents [OSTI]

    Reilly, Peter T.A.

    2012-10-16

    An aerosol particle analyzer includes a laser ablation chamber, a gas-filled conduit, and a mass spectrometer. The laser ablation chamber can be operated at a low pressure, which can be from 0.1 mTorr to 30 mTorr. The ablated ions are transferred into a gas-filled conduit. The gas-filled conduit reduces the electrical charge and the speed of ablated ions as they collide and mix with buffer gases in the gas-filled conduit. Preferably, the gas filled-conduit includes an electromagnetic multipole structure that collimates the nascent ions into a beam, which is guided into the mass spectrometer. Because the gas-filled conduit allows storage of vast quantities of the ions from the ablated particles, the ions from a single ablated particle can be analyzed multiple times and by a variety of techniques to supply statistically meaningful analysis of composition and isotope ratios.

  20. THE DUST PROPERTIES OF z {approx} 3 MIPS-LBGs FROM PHOTOCHEMICAL MODELS

    SciTech Connect (OSTI)

    Fan, X. L. [School of Physics and Electronics Information, Hubei University of Education, 430205 Wuhan (China); Pipino, A. [Institut fur Astronomie, ETH Zurich, CH-8093 Zurich (Switzerland); Matteucci, F., E-mail: fan@oats.inaf.it [Dipartimento di Fisica, Sezione di Astronomia, Universit a di Trieste, via G.B. Tiepolo 11, I-34131 Trieste (Italy)

    2013-05-10

    The stacked spectral energy distribution (SED) 24 {mu}m Lyman break galaxies (MIPS-LBGs) detected by the Multiband Imaging Photometer for Spitzer (MIPS) is fitted by means of the spectrophotometric model GRASIL with an ''educated'' fitting approach which benefits from the results of chemical evolution models. The star formation rate-age-metallicity degeneracies of SED modeling are broken by using star formation history (SFH) and chemical enrichment history suggested by chemical models. The dust mass, dust abundance, and chemical pattern of elements locked in the dust component are also directly provided by chemical models. Using our new ''fitting'' approach, we derive the total mass M{sub tot}, stellar mass M{sub *}, gas mass M{sub g} , dust mass M{sub d} , age, and star formation rate (SFR) of the stacked MIPS-LBG in a self-consistent way. Our estimate of M{sub *} = 8 Multiplication-Sign 10{sup 10} of the stacked MIPS-LBG agrees with other works based on UV-optical SED fitting. We suggest that the MIPS-LBGs at z {approx} 3 are young (0.3-0.6 Gyr), massive (M{sub tot} {approx} 10{sup 11} M{sub Sun }), dusty (M{sub d} {approx} 10{sup 8} M{sub Sun }), and metal-rich (Z {approx} Z{sub Sun }) progenitors of elliptical galaxies undergoing a strong burst of star formation (SFR {approx} 200 M{sub Sun} yr{sup -1}). Our estimate of M{sub d} = 7 Multiplication-Sign 10{sup 7} M{sub Sun} of the stacked MIPS-LBG is about a factor of eight lower than the estimated value based on single temperature graybody fitting, suggesting that self-consistent SED models are needed to estimate dust mass. By comparing with Milky Way molecular cloud and dust properties, we suggest that denser and dustier environments and flatter dust size distribution are likely in high-redshift massive star-forming galaxies. These dust properties, as well as the different types of SFHs, can cause different SED shapes between high-redshift star-forming ellipticals and local starburst templates. This discrepancy of SED shapes could in turn explain the non-detection at submillimeter wavelengths of IR luminous (L{sub IR} Succeeds-Above-Single-Line-Equals-Sign 10{sup 12} L{sub Sun }) MIPS-LBGs.

  1. PHOTOELECTRIC CHARGING OF DUST GRAINS IN THE ENVIRONMENT OF YOUNG STELLAR OBJECTS

    SciTech Connect (OSTI)

    Pedersen, Andreas; Gomez de Castro, Ana I.

    2011-10-20

    The evolution of disks around young stellar objects (YSOs) is deeply affected by the YSOs' ultraviolet (UV) radiation field especially in the 500-1100 A spectral range. The two dominant processes are: the photodissociation of H{sub 2} molecules in the Werner and Lyman bands, and the emission of photoelectrons from dust grains when high energy photons are absorbed. Photoelectrons are an important source of gas heating. In this paper, dust grain charging when exposed to various possible UV fields in the YSOs' environment is investigated. Numerical simulations of the evolution of photoelectrons in the electric field created by the charged dust grains are carried out to obtain the charging profile of dust grains. From the simulations it appears that the different spectra produce significant quantitative and qualitative differences in the charging processes. Both the UV background and the Ae-Herbig star radiation field produce a relatively slow charging of dust grains due to the low fraction of sufficiently energetic photons. The radiation field of T Tauri stars (TTSs) is harder due to the release of magnetic energy in the dense magnetospheric environment. These numerical results have been used to propose a new simple analytical model for grain charging in the atmosphere of protostellar disks around TTSs susceptible to be used in any disk modeling. It has been found that the yield decreases exponentially with the dust charge and that two populations of photoelectrons are produced: a low energy population with mean kinetic energy E = 2.5 eV and a high energy population with E = 5.5-6 eV; the energy dispersion within the populations is {approx}1.3 eV (T {approx} 1.5 x 10{sup 4} K). The high energy population is susceptible of dissociating the H{sub 2} and ionizing some low ionization potential species, such as the Mg. These results add an additional role to dust on the chemistry of the layers just below the H{sub 2} photoionization front. This photoelectic yield has been applied to a simple evaluation of the dust charge in the atmospheres of accretion disks ({alpha}-disks).

  2. Quantum Cellular Automata Without Particles

    E-Print Network [OSTI]

    David A. Meyer; Asif Shakeel

    2015-06-04

    Quantum Cellular Automata (QCA) constitute a natural discrete model for quantum field theory (QFT). Although QFTs are defined without reference to particles, computations are done in terms of Feynman diagrams, which are explicitly interpreted in terms of interacting particles. Similarly, the easiest QCA to construct are Quantum Lattice Gas Automata (QLGA). A natural question then is, "are all nontrivial QCA QLGA?". Here we show by construction that the answer is "no"; thus there are QCA, even in $1+1$ dimensions, that have no particle interpretation.

  3. Next Century Challenges: Mobile Networking for "Smart Dust"

    E-Print Network [OSTI]

    California at Berkeley, University of

    Next Century Challenges: Mobile Networking for "Smart Dust" J. M. Kahn, R. H. Katz (ACM Fellow), K into a complete system. We review the key elements of the emer- gent technology of "Smart Dust" and outline and communica- tion capabilities, and a power supply. Berkeley's Smart Dust project, led by Professors Pister

  4. Mass production of multi-wall carbon nanotubes by metal dusting process with high yield

    SciTech Connect (OSTI)

    Ghorbani, H. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of)] [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of); Rashidi, A.M., E-mail: Rashidiam@ripi.ir [Nanotechnology Research Center, Research Institute of Petroleum Industry (RIPI), West Blvd. Azadi Sport Complex, P.O. Box 14665-1998, Tehran (Iran, Islamic Republic of); Rastegari, S.; Mirdamadi, S. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of)] [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of); Alaei, M. [Nanotechnology Research Center, Research Institute of Petroleum Industry (RIPI), West Blvd. Azadi Sport Complex, P.O. Box 14665-1998, Tehran (Iran, Islamic Republic of)] [Nanotechnology Research Center, Research Institute of Petroleum Industry (RIPI), West Blvd. Azadi Sport Complex, P.O. Box 14665-1998, Tehran (Iran, Islamic Republic of)

    2011-05-15

    Research highlights: {yields} Synthesis of carbon nanotubes over Fe-Ni nanoparticles supported alloy 304L. {yields} Production of carbon nanotubes with high yield (700-1000%) and low cost catalyst. {yields} Optimum growth condition is CO/H{sub 2} = 1/1, 100 cm{sup 3}/min, at 620 {sup o}C under long term repetitive thermal cycling. {yields} Possibility of the mass production by metal dusting process with low cost. -- Abstract: Carbon nanotube materials were synthesized over Fe-Ni nanoparticles generated during disintegration of the surface of alloy 304L under metal dusting environment. The metal dusting condition was simulated and optimized through exposing stainless steel samples during long term repetitive thermal cycling in CO/H{sub 2} = 1/1, total gas flow rate 100 cm{sup 3}/min, at 620 {sup o}C for 300 h. After reaction, surface morphology of the samples and also carbonaceous deposition which had grown on sample surfaces were examined by stereoscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results revealed that multi-wall carbon nanotubes could be formed over nanocatalyst generated on the alloy surface by exploiting metal dusting process. By optimization of reaction parameters the yields of carbon nanotube materials obtained were 700-1000%. Also it has been shown herein that the amount of carbon nanotube materials remarkably increases when the reaction time is extended up to 300 h, indicating a possibility of the mass production by this easy method.

  5. A BOLTZMANN MODEL FOR TRAPPED PARTICLES IN A SURFACE POTENTIAL

    E-Print Network [OSTI]

    Vignal, Marie-Hélène

    A BOLTZMANN MODEL FOR TRAPPED PARTICLES IN A SURFACE POTENTIAL PIERRE DEGOND, C´ELINE PARZANI particles in a surface potential. The potential confines particles close to the surface increasing the charged particle model with some numerical simulations of a gas discharge on a satellite solar array. We

  6. Three-Dimensional Dust Radiative Transfer

    E-Print Network [OSTI]

    Baes, Maarten

    data using 3D dust RT codes. We end with an outlook on the bright future of this field. 63 Annu such as the Solar System (Hoppe et al. 2010), comets and meteoroids (K¨uppers et al. 2005), substellar atmospheres

  7. The general double-dust solution

    E-Print Network [OSTI]

    B. V. Ivanov

    2003-02-04

    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.

  8. Carbon particles

    DOE Patents [OSTI]

    Hunt, Arlon J. (Oakland, CA)

    1984-01-01

    A method and apparatus whereby small carbon particles are made by pyrolysis of a mixture of acetylene carried in argon. The mixture is injected through a nozzle into a heated tube. A small amount of air is added to the mixture. In order to prevent carbon build-up at the nozzle, the nozzle tip is externally cooled. The tube is also elongated sufficiently to assure efficient pyrolysis at the desired flow rates. A key feature of the method is that the acetylene and argon, for example, are premixed in a dilute ratio, and such mixture is injected while cool to minimize the agglomeration of the particles, which produces carbon particles with desired optical properties for use as a solar radiant heat absorber.

  9. THE USE OF DI WATER TO MITIGATE DUSTING FOR ADDITION OF DWPF FRIT TO THE SLURRY MIX EVAPORATOR

    SciTech Connect (OSTI)

    Hansen, E.

    2010-07-21

    The Defense Waste Processing Facility (DPWF) presently is in the process to determine means to reduce water utilization in the Slurry Mix Evaporator (SME) process, thus reducing effluent and processing times. The frit slurry addition system mixes the dry frit with water, yielding approximately a 50 weight percent slurry containing frit and the other fraction water. This slurry is discharged into the SME and excess water is removed via boiling. To reduce this water load to the SME, DWPF has proposed using a pneumatic system in conveying the frit to the SME, in essence a dry delivery system. The problem associated with utilizing a dry delivery system with the existing frit is the generation of dust when discharged into the SME. The use of water has been shown to be effective in the mining industry as well in the DOE complex to mitigate dusting. The method employed by SRNL to determine the quantity of water to mitigate dusting in dry powders was effective, between a lab and bench scale tests. In those tests, it was shown that as high as five weight percent (wt%) of water addition was required to mitigate dust from batches of glass forming minerals used by the Waste Treatment Plant at Hanford, Washington. The same method used to determine the quantity of water to mitigate dusting was used in this task to determine the quantity of water to mitigate this dusting using as-received frit. The ability for water to mitigate dusting is due to its adhesive properties as shown in Figure 1-1. Wetting the frit particles allows for the smaller frit particles (including dust) to adhere to the larger frit particles or to agglomerate into large particles. Fluids other than water can also be used, but their adhesive properties are different than water and the quantity required to mitigate dusting is different, as was observed in reference 1. Excessive water, a few weight percentages greater than that required to mitigate dusting can cause the resulting material not to flow. The primary objective of this task is to perform bench scale testing on various frits that have been used at DWPF or in test programs at SRNL to determine the quantity of de-ionized (DI) water required to mitigate dusting per mass basis of frit. The quantity of DI water required was determined visually by observing the effluent port of the mixer, and DI water addition was made to the point where no visible dust was observed leaving the effluent port. A total of eight different frits were selected for testing. Secondary objectives in this task include the following: (1) Video taping of the de-dusting procedure, (2) Particle size distribution analyses of the dry and wetted frits at the weight fraction of water required for de-dusting, (3) Plate flow tests to determine angle of flow and quantity of material remaining on plate at 90 degrees, (4) Microscopy of dry and wetted frit, and (5) Effect of excess water for selected frits on plate flow. The above analyses were performed within one hour of water addition, to minimize the effect of evaporative water losses. To better understand the size of dust particles, perform settling tests on selected frits and capture the fines. Analyze the fines for particle size distribution. Finally, it is expected that the surface area of frit is an important parameter in the quantity of water required for dust mitigation. An analysis of particle size distribution (PSD) data of as-received frit analyzed by SRNL over the past two to three years will be performed to determine the variation in the distribution of as-received frit. The following objectives were stated in the Technical Task Request4 as objectives that given adequate time would provide insight in helping DWPF in assessing equipment or processes for de-dusting and processing of dry frit. Due to time constraints, commercial methods for dedusting are provided. These results are detailed in section 3.7. Obtain design information from Hanford with respective to equipment used for dedusting. Suggestions on enhanced design features, such as flush water, pipe air purges, humidified compresse

  10. POLARIZED LIGHT IMAGING OF THE HD 142527 TRANSITION DISK WITH THE GEMINI PLANET IMAGER: DUST AROUND THE CLOSE-IN COMPANION

    SciTech Connect (OSTI)

    Rodigas, Timothy J.; Weinberger, Alycia; Follette, Katherine B.; Close, Laird; Hines, Dean C.

    2014-08-20

    When giant planets form, they grow by accreting gas and dust. HD 142527 is a young star that offers a scaled-up view of this process. It has a broad, asymmetric ring of gas and dust beyond ?100 AU and a wide inner gap. Within the gap, a low-mass stellar companion orbits the primary star at just ?12 AU, and both the primary and secondary are accreting gas. In an attempt to directly detect the dusty counterpart to this accreted gas, we have observed HD 142527 with the Gemini Planet Imager in polarized light at Y band (0.95-1.14 ?m). We clearly detect the companion in total intensity and show that its position and photometry are generally consistent with the expected values. We also detect a point source in polarized light that may be spatially separated by ? a few AU from the location of the companion in total intensity. This suggests that dust is likely falling onto or orbiting the companion. Given the possible contribution of scattered light from this dust to previously reported photometry of the companion, the current mass limits should be viewed as upper limits only. If the dust near the companion is eventually confirmed to be spatially separated, this system would resemble a scaled-up version of the young planetary system inside the gap of the transition disk around LkCa 15.

  11. Hazardous Gas Production by Alpha Particles

    SciTech Connect (OSTI)

    Jay A. LaVerne, Principal Investigator

    2001-11-26

    This project focused on the production of hazardous gases in the radiolysis of solid organic matrices, such as polymers and resins, that may be associated with transuranic waste material. Self-radiolysis of radioactive waste is a serious environmental problem because it can lead to a change in the composition of the materials in storage containers and possibly jeopardize their integrity. Experimental determination of gaseous yields is of immediate practical importance in the engineering and maintenance of containers for waste materials. Fundamental knowledge on the radiation chemical processes occurring in these systems allows one to predict outcomes in materials or mixtures not specifically examined, which is a great aid in the management of the variety of waste materials currently overseen by Environmental Management.

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

    SciTech Connect (OSTI)

    Bryan, Charles R.; Enos, David George

    2014-07-01

    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.

  13. Shock-Wave Heating Model for Chondrule Formation: Hydrodynamic Simulation of Molten Droplets exposed to Gas Flows

    E-Print Network [OSTI]

    Hitoshi Miura; Taishi Nakamoto

    2006-11-09

    Millimeter-sized, spherical silicate grains abundant in chondritic meteorites, which are called as chondrules, are considered to be a strong evidence of the melting event of the dust particles in the protoplanetary disk. One of the most plausible scenarios is that the chondrule precursor dust particles are heated and melt in the high-velocity gas flow (shock-wave heating model). We developed the non-linear, time-dependent, and three-dimensional hydrodynamic simulation code for analyzing the dynamics of molten droplets exposed to the gas flow. We confirmed that our simulation results showed a good agreement in a linear regime with the linear solution analytically derived by Sekiya et al. (2003). We found that the non-linear terms in the hydrodynamical equations neglected by Sekiya et al. (2003) can cause the cavitation by producing negative pressure in the droplets. We discussed that the fragmentation through the cavitation is a new mechanism to determine the upper limit of chondrule sizes. We also succeeded to reproduce the fragmentation of droplets when the gas ram pressure is stronger than the effect of the surface tension. Finally, we compared the deformation of droplets in the shock-wave heating with the measured data of chondrules and suggested the importance of other effects to deform droplets, for example, the rotation of droplets. We believe that our new code is a very powerful tool to investigate the hydrodynamics of molten droplets in the framework of the shock-wave heating model and has many potentials to be applied to various problems.

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

    SciTech Connect (OSTI)

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

    2015-01-01

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

  15. Formation of Enceladus' Dust Plume --SUPPLEMENTARY INFORMATION

    E-Print Network [OSTI]

    the plume. 1 Gasdynamics To describe the stationary outflow of vapour from the subsurface reservoir for the addressed process (gas outflow from the reservoir, kept at the water triple point), is expressed in terms on the super-saturation (Fig. S1) = gas (l.g.) eq (Tgas) , (S7) defined as the ratio of the gas density gas

  16. Particle identification

    E-Print Network [OSTI]

    Lippmann, Christian

    2011-01-01

    Particle IDentification (PID) is fundamental to particle physics experiments. This paper reviews PID strategies and methods used by the large LHC experiments, which provide outstanding examples of the state-of-the-art. The first part focuses on the general design of these experiments with respect to PID and the technologies used. Three PID techniques are discussed in more detail: ionization measurements, time-of-flight measurements and Cherenkov imaging. Four examples of the implementation of these techniques at the LHC are given, together with selections of relevant examples from other experiments and short overviews on new developments. Finally, the Alpha Magnetic Spectrometer (AMS 02) experiment is briefly described as an impressive example of a space-based experiment using a number of familiar PID techniques.

  17. Particle identification

    E-Print Network [OSTI]

    Christian Lippmann

    2011-06-12

    Particle IDentification (PID) is fundamental to particle physics experiments. This paper reviews PID strategies and methods used by the large LHC experiments, which provide outstanding examples of the state-of-the-art. The first part focuses on the general design of these experiments with respect to PID and the technologies used. Three PID techniques are discussed in more detail: ionization measurements, time-of-flight measurements and Cherenkov imaging. Four examples of the implementation of these techniques at the LHC are given, together with selections of relevant examples from other experiments and short overviews on new developments. Finally, the Alpha Magnetic Spectrometer (AMS 02) experiment is briefly described as an impressive example of a space-based experiment using a number of familiar PID techniques.

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

    SciTech Connect (OSTI)

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

    2012-03-20

    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.

  19. Metal Dusting of Heat-Resistant Alloys

    E-Print Network [OSTI]

    Al-Meshari, Abdulaziz I.

    dusting can also be a serious problem in other industrial sectors including nuclear plants, coal gasification units, ethylene plants, fuel cells, chemical reactors, steam generators, acetic acid cracking furnaces, and waste heat boilers [14] [15] [16... is catalytically accelerated by contact with iron, nickel, and cobalt. For example, coking which is a chronic problem in ethylene furnaces was thought to be caused by the reduction of a porous (Fe, Ni, Cr) spinel oxide layer at the metal surface...

  20. FORMULATION OF NON-STEADY-STATE DUST FORMATION PROCESS IN ASTROPHYSICAL ENVIRONMENTS

    SciTech Connect (OSTI)

    Nozawa, Takaya [Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Kozasa, Takashi, E-mail: takaya.nozawa@ipmu.jp [Department of Cosmosciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan)

    2013-10-10

    The non-steady-state formation of small clusters and the growth of grains accompanied by chemical reactions are formulated under the consideration that the collision of key gas species (key molecule) controls the kinetics of dust formation process. The formula allows us to evaluate the size distribution and condensation efficiency of dust formed in astrophysical environments. We apply the formulation to the formation of C and MgSiO{sub 3} grains in the ejecta of supernovae, as an example, to investigate how the non-steady effect influences the formation process, condensation efficiency f{sub con,{sub ?}}, and average radius a{sub ave,{sub ?}} of newly formed grains in comparison with the results calculated with the steady-state nucleation rate. We show that the steady-state nucleation rate is a good approximation if the collision timescale of key molecule ?{sub coll} is much smaller than the timescale ?{sub sat} with which the supersaturation ratio increases; otherwise the effect of the non-steady state becomes remarkable, leading to a lower f{sub con,{sub ?}} and a larger a{sub ave,{sub ?}}. Examining the results of calculations, we reveal that the steady-state nucleation rate is applicable if the cooling gas satisfies ? ? ?{sub sat}/?{sub coll} ?> 30 during the formation of dust, and find that f{sub con,{sub ?}} and a{sub ave,{sub ?}} are uniquely determined by ?{sub on} at the onset time t{sub on} of dust formation. The approximation formulae for f{sub con,{sub ?}} and a{sub ave,{sub ?}} as a function of ?{sub on} could be useful in estimating the mass and typical size of newly formed grains from observed or model-predicted physical properties not only in supernova ejecta but also in mass-loss winds from evolved stars.

  1. Particle detection systems and methods

    DOE Patents [OSTI]

    Morris, Christopher L.; Makela, Mark F.

    2010-05-11

    Techniques, apparatus and systems for detecting particles such as muons and neutrons. In one implementation, a particle detection system employs a plurality of drift cells, which can be for example sealed gas-filled drift tubes, arranged on sides of a volume to be scanned to track incoming and outgoing charged particles, such as cosmic ray-produced muons. The drift cells can include a neutron sensitive medium to enable concurrent counting of neutrons. The system can selectively detect devices or materials, such as iron, lead, gold, uranium, plutonium, and/or tungsten, occupying the volume from multiple scattering of the charged particles passing through the volume and can concurrently detect any unshielded neutron sources occupying the volume from neutrons emitted therefrom. If necessary, the drift cells can be used to also detect gamma rays. The system can be employed to inspect occupied vehicles at border crossings for nuclear threat objects.

  2. Gas and dust hydrodynamical simulations of massive lopsided transition discs - I. Gas distribution

    E-Print Network [OSTI]

    Zhu, Zhaohuan

    2015-01-01

    Motivated by lopsided structures observed in some massive transition discs, we have carried out 2D numerical simulations to study vortex structure in massive discs, including the effects of disc self-gravity and the indirect force which is due to the displacement of the central star from the barycenter of the system by the lopsided structure. When only the indirect force is included, we confirm the finding by Mittal & Chiang (2015) that the vortex becomes stronger and can be more than two pressure scale heights wide, as long as the disc-to-star mass ratio is >1%. Such wide vortices can excite strong density waves in the disc and therefore migrate inwards rapidly. However, when disc self-gravity is also considered in simulations, self-gravity plays a more prominent role on the vortex structure. We confirm that when the disc Toomre Q parameter is smaller than pi/(2h), where h is the disc's aspect ratio, the vortices are significantly weakened and their inward migration slows down dramatically. Most importan...

  3. Radio Emitting Dust in the Free-Electron Layer of Spiral Galaxies: Testing the Disk/Halo Interface

    E-Print Network [OSTI]

    A. Ferrara; R. J. Dettmar

    1994-01-10

    We present a study of the radio emission from rotating, charged dust grains immersed in the ionized gas constituting the thick, H$\\alpha$-emitting disk of many spiral galaxies. Using up-to-date optical constants, the charge on the grains exposed to the diffuse galactic UV flux has been calculated. An analytical approximation for the grain charge has been derived, which is then used to obtain the grain rotation frequency. Grains are found to have substantial radio emission peaked at a cutoff frequency in the range 10-100~GHz, depending on the grain size distribution and on the efficiency of the radiative damping of the grain rotation. The dust radio emission is compared to the free-free emission from the ionized gas component; some constraints on the magnetic field strength in the observed dusty filaments are also discussed. The model can be used to test the disk-halo interface environment in spiral galaxies, to determine the amount and size distribution of dust in their ionized component, and to investigate the rotation mechanisms for the dust. Numerical estimates are given for experimental purposes.

  4. Technology Assessment of Dust Suppression Techniques Applied During Structural Demolition

    SciTech Connect (OSTI)

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

    1998-10-20

    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.

  5. Interstellar and ejecta dust in the cas a supernova remnant

    SciTech Connect (OSTI)

    Arendt, Richard G.; Dwek, Eli; Kober, Gladys; Rho, Jeonghee; Hwang, Una

    2014-05-01

    Infrared continuum observations provide a means of investigating the physical composition of the dust in the ejecta and swept up medium of the Cas A supernova remnant (SNR). Using low-resolution Spitzer IRS spectra (5-35 ?m), and broad-band Herschel PACS imaging (70, 100, and 160 ?m), we identify characteristic dust spectra, associated with ejecta layers that underwent distinct nuclear burning histories. The most luminous spectrum exhibits strong emission features at ?9 and 21 ?m and is closely associated with ejecta knots with strong Ar emission lines. The dust features can be reproduced by magnesium silicate grains with relatively low Mg to Si ratios. Another dust spectrum is associated with ejecta having strong Ne emission lines. It has no indication of any silicate features and is best fit by Al{sub 2}O{sub 3} dust. A third characteristic dust spectrum shows features that are best matched by magnesium silicates with a relatively high Mg to Si ratio. This dust is primarily associated with the X-ray-emitting shocked ejecta, but it is also evident in regions where shocked interstellar or circumstellar material is expected. However, the identification of dust composition is not unique, and each spectrum includes an additional featureless dust component of unknown composition. Colder dust of indeterminate composition is associated with emission from the interior of the SNR, where the reverse shock has not yet swept up and heated the ejecta. Most of the dust mass in Cas A is associated with this unidentified cold component, which is ? 0.1 M {sub ?}. The mass of warmer dust is only ?0.04 M {sub ?}.

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

    SciTech Connect (OSTI)

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

    2011-12-31

    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.

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

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Scanza, R. A.; Mahowald, N.; Ghan, S.; Zender, C. S.; Kok, J. F.; Liu, X.; Zhang, Y.

    2014-07-02

    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 componentsmore »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 +0.05 W m?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 +0.17 W m?2) and of dust with optimized optical properties, wet scavenging and particle size distribution in CAM4 and CAM5, ?0.05 and ?0.17 W m?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.« less

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

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

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

    2015-01-01

    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 componentsmore »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 + 0.05 Wm?² for both CAM4 and CAM5 simulations with mineralogy. We compare this to the radiative forcing from simulations of dust in release versions of CAM4 and CAM5 (+0.08 and +0.17 Wm?²) and of dust with optimized optical properties, wet scavenging and particle size distribution in CAM4 and CAM5, -0.05 and -0.17 Wm?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.« less

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

    SciTech Connect (OSTI)

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

    2015-01-01

    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 + 0.05 Wm?² for both CAM4 and CAM5 simulations with mineralogy. We compare this to the radiative forcing from simulations of dust in release versions of CAM4 and CAM5 (+0.08 and +0.17 Wm?²) and of dust with optimized optical properties, wet scavenging and particle size distribution in CAM4 and CAM5, -0.05 and -0.17 Wm?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.

  10. Acid rain control strategists overlook dust removal benefits

    SciTech Connect (OSTI)

    Not Available

    1989-09-01

    Various strategies for controlling acid rain by reducing SO{sub 2} from existing utilities have failed to take into account the incidental particulate removal abilities of SO{sub 2} scrubbers. This has resulted in over-estimating the costs of acid rain control by 25% or more. This oversight has also caused utilities to invest in preliminary engineering of precipitator upgrades which will never have to be made if scrubbers are installed. While it seems inexplicable that a factor of this importance could have been overlooked by the industry, it is because of the unique situation in old U.S. utility power plants. These plants have relatively inefficient particulate control equipment which is not subject to new source performance standards. New power plants incorporate highly efficient particulate control devices so the ability of the downstream scrubbers to remove dust is irrelevant. The very small amount of particulate entering the scrubber from a highly efficient precipitator could be offset by escaping sulfate particles from a poorly operated scrubber. So an informal guideline was established to indicate that the scrubber had no overall effect on particulate emissions. The industry has generalized upon this guideline when, in fact, it only applies to new plants. The McIlvaine Company in its FGD Knowledge Network has thoroughly documented evidence that SO{sub 2} scrubbers will remove as much as 95% of the particulate being emitted from the relatively low efficiency precipitators operating on the nations existing coal-fired power plants.

  11. The dust grain size - stellar luminosity trend in debris discs

    E-Print Network [OSTI]

    Pawellek, Nicole

    2015-01-01

    The cross section of material in debris discs is thought to be dominated by the smallest grains that can still stay in bound orbits despite the repelling action of stellar radiation pressure. Thus the minimum (and typical) grain size $s_\\text{min}$ is expected to be close to the radiation pressure blowout size $s_\\text{blow}$. Yet a recent analysis of a sample of Herschel-resolved debris discs showed the ratio $s_\\text{min}/s_\\text{blow}$ to systematically decrease with the stellar luminosity from about ten for solar-type stars to nearly unity in the discs around the most luminous A-type stars. Here we explore this trend in more detail, checking how significant it is and seeking to find possible explanations. We show that the trend is robust to variation of the composition and porosity of dust particles. For any assumed grain properties and stellar parameters, we suggest a recipe of how to estimate the "true" radius of a spatially unresolved debris disc, based solely on its spectral energy distribution. The r...

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

    SciTech Connect (OSTI)

    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

    2014-01-03

    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.

  13. NUMERICAL MODELING OF THE COAGULATION AND POROSITY EVOLUTION OF DUST AGGREGATES

    SciTech Connect (OSTI)

    Okuzumi, Satoshi; Sakagami, Masa-aki [Graduate School of Human and Environmental Studies, Kyoto University, Yoshida-nihonmatsu-cho, Sakyo-ku, Kyoto 606-8501 (Japan); Tanaka, Hidekazu, E-mail: satoshi.okuzumi@ax2.ecs.kyoto-u.ac.j [Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819 (Japan)

    2009-12-20

    Porosity evolution of dust aggregates is crucial in understanding dust evolution in protoplanetary disks. In this study, we present useful tools to study the coagulation and porosity evolution of dust aggregates. First, we present a new numerical method for simulating dust coagulation and porosity evolution as an extension of the conventional Smoluchowski equation. This method follows the evolution of the mean porosity for each aggregate mass simultaneously with the evolution of the mass distribution function. This method reproduces the results of previous Monte Carlo simulations with much less computational expense. Second, we propose a new collision model for porous dust aggregates on the basis of our N-body experiments on aggregate collisions. As the first step, we focus on 'hit-and-stick' collisions, which involve neither compression nor fragmentation of aggregates. We first obtain empirical data on porosity changes between the classical limits of ballistic cluster-cluster and particle-cluster aggregation. Using the data, we construct a recipe for the porosity change due to general hit-and-stick collisions as well as formulae for the aerodynamical and collisional cross sections. Our collision model is thus more realistic than a previous model of Ormel et al. based on the classical aggregation limits only. Simple coagulation simulations using the extended Smoluchowski method show that our collision model explains the fractal dimensions of porous aggregates observed in a full N-body simulation and a laboratory experiment. By contrast, similar simulations using the collision model of Ormel et al. result in much less porous aggregates, meaning that this model underestimates the porosity increase upon unequal-sized collisions. Besides, we discover that aggregates at the high-mass end of the distribution can have a considerably small aerodynamical cross section per unit mass compared with aggregates of lower masses. This occurs when aggregates drift under uniform acceleration (e.g., gravity) and their collision is induced by the difference in their terminal velocities. We point out an important implication of this discovery for dust growth in protoplanetary disks.

  14. Tungsten dust impact on ITER-like plasma edge

    SciTech Connect (OSTI)

    Smirnov, R. D. Krasheninnikov, S. I.; Pigarov, A. Yu.; Rognlien, T. D.

    2015-01-15

    The impact of tungsten dust originating from divertor plates on the performance of edge plasma in ITER-like discharge is evaluated using computer modeling with the coupled dust-plasma transport code DUSTT-UEDGE. Different dust injection parameters, including dust size and mass injection rates, are surveyed. It is found that tungsten dust injection with rates as low as a few mg/s can lead to dangerously high tungsten impurity concentrations in the plasma core. Dust injections with rates of a few tens of mg/s are shown to have a significant effect on edge plasma parameters and dynamics in ITER scale tokamaks. The large impact of certain phenomena, such as dust shielding by an ablation cloud and the thermal force on tungsten ions, on dust/impurity transport in edge plasma and consequently on core tungsten contamination level is demonstrated. It is also found that high-Z impurities provided by dust can induce macroscopic self-sustained plasma oscillations in plasma edge leading to large temporal variations of edge plasma parameters and heat load to divertor target plates.

  15. Nanodiamond dust and the energy distribution of quasars

    E-Print Network [OSTI]

    L. Binette; A. C. Andersen; H. Mutschke; S. Haro-Corzo

    2005-09-24

    The spectral energy distribution of quasars shows a sharp steepening of the continuum shortward of ~ 1100 A. The steepening could be a result of dust absorption. We present a dust extinction model which considers crystalline carbon grains and compare it with SMC-like dust extinction consisting of a mixture of silicate grains with graphite or amorphous carbon grains. We show that the sharp break seen in individual quasar spectra of intermediate redshif \\~ 1-2 can be reproduced by dust absorption provided the extinction curve consists of nanodiamonds, composed of terrestial cubic diamonds or of diamonds similar to the presolar nanodiamonds found in primitive meteorites.

  16. Nanodiamond dust and the energy distribution of quasars

    E-Print Network [OSTI]

    Binette, L; Mutschke, H; Haro-Corzo, S

    2005-01-01

    The spectral energy distribution of quasars shows a sharp steepening of the continuum shortward of ~ 1100 A. The steepening could be a result of dust absorption. We present a dust extinction model which considers crystalline carbon grains and compare it with SMC-like dust extinction consisting of a mixture of silicate grains with graphite or amorphous carbon grains. We show that the sharp break seen in individual quasar spectra of intermediate redshif \\~ 1-2 can be reproduced by dust absorption provided the extinction curve consists of nanodiamonds, composed of terrestrial cubic diamonds or of diamonds similar to the presolar nanodiamonds found in primitive meteorites.

  17. Chemical evolution of galaxies with radiation-driven dust wind

    E-Print Network [OSTI]

    Bekki, Kenji

    2014-01-01

    We discuss how the removal of interstellar dust by radiation pressure of stars influences the chemical evolution of galaxies by using a new one-zone chemical evolution models with dust wind. The removal efficiency of an element (e.g., Fe, Mg, and Ca) through radiation-driven dust wind in a galaxy is assumed to depend both on the dust depletion level of the element in interstellar medium and the total luminosity of the galaxy in the new model. We particularly focus on the time evolution of [alpha/Fe] and its dependence on model parameters for dust wind in this study. The principal results are as follows. The time evolution of [Ca/Fe] is significantly different between models with and without dust wind in the sense that [Ca/Fe] can be systematically lower in the models with dust wind. The time evolution of [Mg/Fe], on the other hand, can not be so different between the models with and without dust wind owing to the lower level of dust depletion for Mg. As a result of this, [Mg/Ca] can be systematically higher i...

  18. Desert dust suppressing precipitation: A possible desertification feedback loop

    E-Print Network [OSTI]

    Daniel, Rosenfeld

    Desert dust suppressing precipitation: A possible desertification feedback loop Daniel Rosenfeld of land use exposing the topsoil can initiate such a desertification feedback process. Satellite

  19. In-Situ Characterization of Cloud Condensation Nuclei, Interstitial, and background Particles using Single Particle Mass Spectrometer, SPLAT II

    SciTech Connect (OSTI)

    Zelenyuk, Alla; Imre, D.; Earle, Michael; Easter, Richard C.; Korolev, Alexei; Leaitch, W. R.; Liu, Peter; Macdonald, A. M.; Ovchinnikov, Mikhail; Strapp, Walter

    2010-10-01

    Aerosol indirect effect remains the most uncertain aspect of climate change modeling because proper test requires knowledge of individual particles sizes and compositions with high spatial and temporal resolution. We present the first deployment of a single particle mass spectrometer (SPLAT II) that is operated in a dual data acquisition mode to measure all the required individual particle properties with sufficient temporal resolution to definitively resolve the aerosol-cloud interaction in this exemplary case. We measured particle number concentrations, asphericity, and individual particle size, composition, and density with better than 60 seconds resolution. SPLAT II measured particle number concentrations between 70 particles cm-3and 300 particles cm-3, an average particle density of 1.4 g cm-3. Found that most particles are composed of oxygenated organics, many of which are mixed with sulfates. Biomass burn particles some with sulfates were prevalent, particularly at higher altitudes, and processed sea-salt was observed over the ocean. Analysis of cloud residuals shows that with time cloud droplets acquire sulfate by the reaction of peroxide with SO2. Based on the particle mass spectra and densities we find that the compositions of cloud condensation nuclei are similar to those of background aerosol but, contain on average ~7% more sulfate, and do not include dust and metallic particles. A comparison between the size distributions of background, activated, and interstitial particles shows that while nearly none of the activated particles is smaller than 115 nm, more than 80% of interstitial particles are smaller than 115 nm. We conclude that for this cloud the most important difference between CCN and background aerosol is particle size although having more sulfate also helps.

  20. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Comments?govInstrumentsnoaacrnBarrow, Alaska OutreachCalendar NSAProductsMerged and corrected 915Dust Observations

  1. Can a photometric redshift code reliably determine dust extinction?

    E-Print Network [OSTI]

    T. S. R Babbedge; R. Whitaker; S. Morris

    2005-05-05

    Photometric redshifts can be routinely obtained to accuracies of better than 0.1 in Delta(z)/(1+z). However, the issue of dust extinction is one that has still not been well quantified. In this paper the success of two template-fitting photometric redshift codes (IMPZ and HYPERZ) at reliably returning Av in addition to redshift is explored. New data on the CNOC2 spectroscopic sample of 0.2gas- and star- derived extinction, as determined by Calzetti (2001), is necessarily the best value for this sample. When comparing the two codes to the Balmer-derived Av, a correlation between the photometrically derived Av, Phot-Av, and the Balmer-Av is found. The correlation is improved when the empirical value of gamma=0.44 is allowed to vary. From least-squares-fitting the minimum in the reduced chi^2 distribution is found for gamma~0.25 +/- 0.2. For the sample of galaxies here, the factor of two difference in covering factor implied by the Calzetti ratio is found to be plausible. The CNOC2 galaxies with detected Balmer lines have some preference for an increased covering factor difference, which would perhaps imply they are undergoing more rapid, `bursty' star formation than the galaxies Calzetti used in her derivation.

  2. A SHORT-DURATION EVENT AS THE CAUSE OF DUST EJECTION FROM MAIN-BELT COMET P/2012 F5 (GIBBS)

    SciTech Connect (OSTI)

    Moreno, F. [Instituto de Astrofisica de Andalucia, CSIC, Glorieta de la Astronomia s/n, E-18008 Granada (Spain); Licandro, J.; Cabrera-Lavers, A., E-mail: fernando@iaa.es [Instituto de Astrofisica de Canarias, c/Via Lactea s/n, E-38200 La Laguna, Tenerife (Spain)

    2012-12-10

    We present observations and an interpretative model of the dust environment of the Main-Belt Comet P/2010 F5 (Gibbs). The narrow dust trails observed can be interpreted unequivocally as an impulsive event that took place around 2011 July 1 with an uncertainty of {+-}10 days, and a duration of less than a day, possibly of the order of a few hours. The best Monte Carlo dust model fits to the observed trail brightness imply ejection velocities in the range 8-10 cm s{sup -1} for particle sizes between 30 cm and 130 {mu}m. This weak dependence of velocity on size contrasts with that expected from ice sublimation and agrees with that found recently for (596) Scheila, a likely impacted asteroid. The particles seen in the trail are found to follow a power-law size distribution of index Almost-Equal-To -3.7. Assuming that the slowest particles were ejected at the escape velocity of the nucleus, its size is constrained to about 200-300 m in diameter. The total ejected dust mass is {approx}> 5 Multiplication-Sign 10{sup 8} kg, which represents approximately 4%-20% of the nucleus mass.

  3. Investigation of Techniques to Improve Continuous Air Monitors Under Conditions of High Dust Loading in Environmental Settings

    SciTech Connect (OSTI)

    Suilou Huang; Stephen D. Schery; John C. Rodgers

    2002-07-23

    A number of DOE facilities, such as the Los Alamos National Laboratory (LANL) and the Waste Isolation Pilot Plant (WIPP), use alpha-particle environmental continuous air monitors (ECAMs) to monitor air for unwanted releases of radioactive aerosols containing such materials as plutonium and uranium. High sensitivity, ease of operation, and lack of false alarms are all important for ECAMs. The object of the project was to conduct investigations to improve operation of ECAMs, particularly under conditions where a lot of nonradioactive dust may be deposited on the filters (conditions of high dust loading). The presence of such dust may increase the frequency with which filters must be changed and can lead to an increased incidence of false alarms due to deteriorated energy resolution and response specificity to the radionuclides of interest. A major finding of the investigation, not previously documented, was that under many conditions thick layers of underlying nonradioactive dust do not decrease energy resolution and specificity for target radionuclides if the radioactive aerosol arrives as a sudden thin burst deposit, as commonly occurs in the early-warning alarm mode. As a result, operators of ECAMs may not need to change filters as often as previously thought and have data upon which to base more reliable operating procedures.

  4. ANALYSIS OF DUST DELIQUESCENCE FOR FEP SCREENING

    SciTech Connect (OSTI)

    C. Bryan

    2005-08-26

    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.

  5. A comparison of chemistry and dust cloud formation in ultracool dwarf model atmospheres

    E-Print Network [OSTI]

    Ch. Helling; A. Ackerman; F. Allard; M. Dehn; P. Hauschildt; D. Homeier; K. Lodders; M. Marley; F. Rietmeijer; T. Tsuji; P. Woitke

    2008-09-24

    The atmospheres of substellar objects contain clouds of oxides, iron, silicates, and other refractory condensates. Water clouds are expected in the coolest objects. The opacity of these `dust' clouds strongly affects both the atmospheric temperature-pressure profile and the emergent flux. Thus any attempt to model the spectra of these atmospheres must incorporate a cloud model. However the diversity of cloud models in atmospheric simulations is large and it is not always clear how the underlying physics of the various models compare. Likewise the observational consequences of different modeling approaches can be masked by other model differences, making objective comparisons challenging. In order to clarify the current state of the modeling approaches, this paper compares five different cloud models in two sets of tests. Test case 1 tests the dust cloud models for a prescribed L, L--T, and T-dwarf atmospheric (temperature T, pressure p, convective velocity vconv)-structures. Test case 2 compares complete model atmosphere results for given (effective temperature Teff, surface gravity log g). All models agree on the global cloud structure but differ in opacity-relevant details like grain size, amount of dust, dust and gas-phase composition. Comparisons of synthetic photometric fluxes translate into an modelling uncertainty in apparent magnitudes for our L-dwarf (T-dwarf) test case of 0.25 < \\Delta m < 0.875 (0.1 < \\Delta m M 1.375) taking into account the 2MASS, the UKIRT WFCAM, the Spitzer IRAC, and VLT VISIR filters with UKIRT WFCAM being the most challenging for the models. (abr.)

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

    E-Print Network [OSTI]

    M. Villar-Martin; L. Binette

    1995-11-24

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

  7. Revisiting Smart Dust with RFID Sensor Networks Michael Buettner

    E-Print Network [OSTI]

    Hochberg, Michael

    of applications such as dense environmental monitoring, sensor rich home automation and smart environmentsRevisiting Smart Dust with RFID Sensor Networks Michael Buettner University of Washington Ben and computation platforms that leverage RFID technology can realize "smart-dust" ap- plications that have eluded

  8. SULFATE AND NITRATE COATINGS ON MINERAL DUSTS: CRYSTALLINE OR AQUEOUS?

    E-Print Network [OSTI]

    SULFATE AND NITRATE COATINGS ON MINERAL DUSTS: CRYSTALLINE OR AQUEOUS? Scot T. Martin, Hui Observational evidence shows that mineral dusts in Asian outflows become coated by sulfates and nitrates. Layer), and the asymmetry parameter. The aqueous coatings also provide milieu for aqueous chemical reactions

  9. A Study of Dust Movement through Construction Barriers 

    E-Print Network [OSTI]

    Zhang, Wei

    2014-12-12

    that models a construction site in a laboratory setting. The results demonstrate movement of the dust occurs with the provision of an opening in a plastic construction wall. The filter collection system analysis showed that the distribution of the dust did...

  10. Concrete Dust Suppression System. Innovative Technology Summary Report

    SciTech Connect (OSTI)

    1998-12-01

    The improved technology is a water-based dust suppression system for controlling concrete dust generated by demolition equipment, in this case a demolition ram. This demonstration was performed to assess the effectiveness of this system to (1) minimize the amount of water used to suppress potentially contaminated dust, (2) focus the water spray on the dust-generating source and (3) minimize the dust cloud generated by the demolition activity. The technology successfully reduced the water required by a factor of eight compared to the traditional (baseline) method, controlled the dust generated, and permitted a reduction in the work force. The water spray can be focused at the ram point, but it is affected by wind. Prior to the use of this dust control system, dust generated by the demolition ram was controlled manually by spraying with fire hoses (the baseline technology). The improved technology is 18% less expensive than the baseline technology for the conditions and parameters of this demonstration, however, the automated system can save up to 80% versus the baseline whenever waste water treatment costs are considered. For demolishing one high-walled room and a long slab with a total of 413 m{sup 3} (14,580 ft{sup 3}) of concrete, the savings are $105,000 (waste water treatment included). The improved technology reduced the need for water consumption and treatment by about 88% which results in most of the savings.

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

    E-Print Network [OSTI]

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

    2010-01-01

    aluminium, calcium, iron and some traces of potassium and magnetism. On the other hand, ASHRAE and SAE coarse dust contains carbon and they also consist of mainly silica. SAE fine dust contains aluminium, calcium and traces of potassium. From... such chemical analysis, the ASHRAE dust seems to be the closest to the Kuwaiti dust from silica-content standpoint. However, analysis of the ASHRAE dust does not show any presence of aluminium, calcium and traces of potassium which are found in the Kuwaiti...

  12. On the dry deposition of submicron particles

    SciTech Connect (OSTI)

    Wesely, M. L.

    1999-10-08

    The air-surface exchange of particles can have a strong role in determining the amount, size, and chemical composition of particles in the troposphere. Here the authors consider only dry processes (deposition processes not directly aided by precipitation) and mostly address particles less than about 2 {micro}m in diameter (often referred to as submicron particles because most of such particles are less than 1 {micro}m in diameter). The processes that control the dry exchange of particulate material between the atmosphere and the surface of the Earth are numerous, highly varied, and sometimes poorly understood. As a result, determining which of the surface processes to parameterize or simulate in modeling the tropospheric mass budget of a particulate substance can be a significant challenge. Dry deposition, for example, can be controlled by a combination of Brownian diffusion, impaction, interception, and gravitational settling, depending on the size of the particles, the roughness of the surface on both micrometeorological and microscopic scales, the geometrical structure of vegetative canopies, and other surface characteristics such as wetness. Particles can be added to the lower atmosphere by resuspension from land surfaces and sea spray. The roles of rapid gas-to-particle conversion and growth or shrinkage of particles as a result of water condensation or evaporation in the lower few meters of the atmosphere can also have a significant impact on particle concentrations in the lower atmosphere. Here, a few micrometeorological observations and inferences on particle air-surface exchange are briefly addressed.

  13. Existence domains of dust-acoustic solitons and supersolitons

    SciTech Connect (OSTI)

    Maharaj, S. K.; Bharuthram, R.; Singh, S. V.; Lakhina, G. S.

    2013-08-15

    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.

  14. Sheath formation under collisional conditions in presence of dust

    SciTech Connect (OSTI)

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

    2014-08-15

    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.

  15. Particle pressures in fluidized beds. Final report

    SciTech Connect (OSTI)

    Campbell, C.S.; Rahman, K.; Jin, C.

    1996-09-01

    This project studies the particle pressure, which may be thought of as the force exerted by the particulate phase of a multiphase mixture, independently of that exerted by other phases. The project is divided into two parts, one concerning gas and the other liquid fluidized beds. Previous work on gas fluidized beds had suggested that the particle pressures are generated by bubbling action. Thus, for these gas fluidized bed studies, the particle pressure is measured around single bubbles generated in 2-D fluidized beds, using special probes developed especially for this purpose. Liquid beds are immune from bubbling and the particle pressures proved too small to measure directly. However, the major interest in particle pressures in liquid beds lies in their stabilizing effect that arises from the effective elasticity (the derivative of the particle pressure with respect to the void fraction), they impart to the bed. So rather than directly measure the particle pressure, the authors inferred the values of the elasticity from measurements of instability growth in liquid beds; the inference was made by first developing a generic stability model (one with all the normally modeled coefficients left undetermined) and then working backwards to determine the unknown coefficients, including the elasticity.

  16. Particle Pressures in Fluidized Beds. Final report

    SciTech Connect (OSTI)

    Campbell, C.S.; Rahman, K.; Jin, C.

    1996-09-01

    This project studies the particle pressure, which may be thought of as the force exerted by the particulate phase of a multiphase mixture, independently of that exerted by other phases. The project is divided into two parts, one concerning gas and the other liquid fluidized beds. Previous work on gas fluidized beds had suggested that the particle pressures are generated by bubbling action. Thus, for these gas fluidized bed studies, the particle pressure is measured around single bubbles generated in 2-D fluidized beds, using special probes developed especially for this purpose. Liquid beds are immune from bubbling and the particle pressures proved too small to measure directly. However, the major interest in particle pressures in liquid beds lies in their stabilizing effect that arises from the effective elasticity (the derivative of the particle pressure with respect to the void fraction): they impart to the bed. So rather than directly measure the particle pressure, we inferred the values of the elasticity from measurements of instability growth in liquid beds the inference was made by first developing a generic stability model (one with all the normally modeled coefficients left undetermined)and then working backwards to determine the unknown coefficients, including the elasticity.

  17. Effect of the radio frequency discharge on the dust charging process in a weakly collisional and fully ionized plasma

    SciTech Connect (OSTI)

    Motie, Iman; Bokaeeyan, Mahyar

    2015-02-15

    A close analysis of dust charging process in the presence of radio frequency (RF) discharge on low pressure and fully ionized plasma for both weak and strong discharge's electric field is considered. When the electromagnetic waves pass throughout fully ionized plasma, the collision frequency of the plasma is derived. Moreover, the disturbed distribution function of plasma particles in the presence of the RF discharge is obtained. In this article, by using the Krook model, we separate the distribution function in two parts, the Maxwellian part and the perturbed part. The perturbed part of distribution can make an extra current, so-called the accretion rate of electron (or ion) current, towards a dust particle as a function of the average electron-ion collision frequency. It is proven that when the potential of dust grains increases, the accretion rate of electron current experiences an exponential reduction. Furthermore, the accretion rate of electron current for a strong electric field is relatively smaller than that for a weak electric field. The reasons are elaborated.

  18. Shock Acceleration of the Energetic Particle Background in the Solar Wind David T. Sodaitis

    E-Print Network [OSTI]

    on planet Earth, the solar wind is an important topic for study because it is strongly influenced by solar activity, and it transfers that solar influence "to planets, comets, dust particles, and cosmic rays of three components, a fluid model of the sun's corona which in it's equilibrium state creates a supersonic

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

    SciTech Connect (OSTI)

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

    2014-05-15

    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.

  20. A new method to generate dust with astrophysical properties

    SciTech Connect (OSTI)

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

    2010-04-21

    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.

  1. Advanced Characterization of Particles and Particle-Cell Interactions...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Characterization of Particles and Particle-Cell Interactions Advanced Characterization of Particles and Particle-Cell Interactions 2004 Diesel Engine Emissions Reduction (DEER)...

  2. An Alternate Approach to Determine the Explosibility of Dusts 

    E-Print Network [OSTI]

    Ganesan, Balaji

    2013-12-04

    Figure 3. A deflagration fueled by corn starch in the CAAQES chamber at 50 g m-3 ..... 20 Figure 4. The characteristic PvT curves obtained for corn starch at a concentration of 50 g m-3 for three replications... ........................................................................ 28 Figure 7. Explosibility tests conducted for CGD in the CAAQES chamber ................... 36 Figure 8. The characteristic PvT curves for gin dust at a concentration of 1000 g m-3 ... 36 Figure 9. A dust explosion fueled by Dust XX at a...

  3. The peculiar dust shell of Nova DZ Cru (2003).

    SciTech Connect (OSTI)

    Evans, A.; Gehrz, R. D.; Woodward, C. E.; Helton, L. A.; Rushton, M. T.; Bode, M. F.; Krautter, J.; Lyke, J.; Lynch, D. K.; Ness, J.-U.; Starrfield, S.; Truran, J. W.; Wagner, R. M.; Physics; Keele Univ.; Univ. of Minnesota; Univ. of Central Lancashire; Liverpool John Moores Univ.; Zentrum fur Astronomie der Univ. Heidelberg; M. W. Keck Observatory; The Aerospace Corp.; European Space Astronomy Centre; Arizona State Univ.; Univ. of Chicago; Large Binocular Telscope Observatory

    2010-01-01

    We present Spitzer Space Telescope observations of the 'peculiar variable' DZ Cru, identified by Rushton et al. as a classical nova. A dust shell, on which are superimposed a number of features, is prominent in the 5-35 {micro}m range some 4 yr after eruption. We suggest that the dust in DZ Cru is primarily hydrogenated amorphous carbon in which aliphatic bands currently predominate and which may become either predominantly aromatic as the dust is photoprocessed by ultraviolet radiation from the stellar remnant or more likely completely destroyed.

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

    SciTech Connect (OSTI)

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

    2009-07-15

    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.

  5. Particle Physics Booklet 2008

    E-Print Network [OSTI]

    et al., C. Amsler

    2008-01-01

    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

  6. Statistics of particle time-temperature histories.

    SciTech Connect (OSTI)

    Hewson, John C.; Lignell, David O.; Sun, Guangyuan

    2014-10-01

    Particles in non - isothermal turbulent flow are subject to a stochastic environment tha t produces a distribution of particle time - temperature histories. This distribution is a function of the dispersion of the non - isothermal (continuous) gas phase and the distribution of particles relative to that gas phase. In this work we extend the one - dimensional turbulence (ODT) model to predict the joint dispersion of a dispersed particle phase and a continuous phase. The ODT model predicts the turbulent evolution of continuous scalar fields with a model for the cascade of fluctuations to smaller sc ales (the 'triplet map') at a rate that is a function of the fully resolved one - dimens ional velocity field . Stochastic triplet maps also drive Lagrangian particle dispersion with finite Stokes number s including inertial and eddy trajectory - crossing effect s included. Two distinct approaches to this coupling between triplet maps and particle dispersion are developed and implemented along with a hybrid approach. An 'instantaneous' particle displacement model matches the tracer particle limit and provide s an accurate description of particle dispersion. A 'continuous' particle displacement m odel translates triplet maps into a continuous velocity field to which particles respond. Particles can alter the turbulence, and modifications to the stochastic rate expr ession are developed for two - way coupling between particles and the continuous phase. Each aspect of model development is evaluated in canonical flows (homogeneous turbulence, free - shear flows and wall - bounded flows) for which quality measurements are ava ilable. ODT simulations of non - isothermal flows provide statistics for particle heating. These simulations show the significance of accurately predicting the joint statistics of particle and fluid dispersion . Inhomogeneous turbulence coupled with the in fluence of the mean flow fields on particles of varying properties alter s particle dispersion. The joint particle - temperature dispersion leads to a distribution of temperature histories predicted by the ODT . Predictions are shown for the lower moments an d the full distributions of the particle positions, particle - observed gas temperatures and particle temperatures. An analysis of the time scales affecting particle - temperature interactions covers Lagrangian integral time scales based on temperature autoco rrelations, rates of temperature change associated with particle motion relative to the temperature field and rates of diffusional change of temperatures. These latter two time scales have not been investigated previously; they are shown to be strongly in termittent having peaked distributions with long tails. The logarithm of the absolute value of these time scales exhibits a distribution closer to normal. A cknowledgements This work is supported by the Defense Threat Reduction Agency (DTRA) under their Counter - Weapons of Mass Destruction Basic Research Program in the area of Chemical and Biological Agent Defeat under award number HDTRA1 - 11 - 4503I to Sandia National Laboratories. The authors would like to express their appreciation for the guidance provi ded by Dr. Suhithi Peiris to this project and to the Science to Defeat Weapons of Mass Destruction program.

  7. On the source of the dust extinction in type Ia supernovae and the discovery of anomalously strong Na I absorption

    SciTech Connect (OSTI)

    Phillips, M. M.; Morrell, Nidia; Hsiao, E. Y.; Campillay, Abdo; Contreras, Carlos [Carnegie Observatories, Las Campanas Observatory, Casilla 601, La Serena (Chile); Simon, Joshua D.; Burns, Christopher R.; Persson, Sven E.; Thompson, I. B.; Freedman, Wendy L. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara St., Pasadena, CA 91101 (United States); Cox, Nick L. J. [Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D bus 2401, 3001 Leuven (Belgium); Foley, Ryan J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Karakas, Amanda I. [Research School of Astronomy and Astrophysics, The Australian National University, Weston, ACT 2611 (Australia); Patat, F. [European Southern Observatory (ESO), Karl Schwarschild Strasse 2, D-85748, Garching bei München (Germany); Sternberg, A. [Max Planck Institute for Astrophysics, Karl Schwarzschild Strasse 1, D-85741 Garching bei München (Germany); Williams, R. E. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Gal-Yam, A. [Benoziyo Center for Astrophysics, Faculty of Physics, Weizmann Institute of Science, Rehovot 76100 (Israel); Leonard, D. C. [Department of Astronomy, San Diego State University, San Diego, CA 92182 (United States); Stritzinger, Maximilian [Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Folatelli, Gastón, E-mail: mmp@lco.cl [Kavli Institute for the Physics and Mathematics of the Universe, Todai Institutes for Advanced Study, the University of Tokyo, Kashiwa 277-8583 (Japan); and others

    2013-12-10

    High-dispersion observations of the Na I D ??5890, 5896 and K I ??7665, 7699 interstellar lines, and the diffuse interstellar band at 5780 Å in the spectra of 32 Type Ia supernovae are used as an independent means of probing dust extinction. We show that the dust extinction of the objects where the diffuse interstellar band at 5780 Å is detected is consistent with the visual extinction derived from the supernova colors. This strongly suggests that the dust producing the extinction is predominantly located in the interstellar medium of the host galaxies and not in circumstellar material associated with the progenitor system. One quarter of the supernovae display anomalously large Na I column densities in comparison to the amount of dust extinction derived from their colors. Remarkably, all of the cases of unusually strong Na I D absorption correspond to 'Blueshifted' profiles in the classification scheme of Sternberg et al. This coincidence suggests that outflowing circumstellar gas is responsible for at least some of the cases of anomalously large Na I column densities. Two supernovae with unusually strong Na I D absorption showed essentially normal K I column densities for the dust extinction implied by their colors, but this does not appear to be a universal characteristic. Overall, we find the most accurate predictor of individual supernova extinction to be the equivalent width of the diffuse interstellar band at 5780 Å, and provide an empirical relation for its use. Finally, we identify ways of producing significant enhancements of the Na abundance of circumstellar material in both the single-degenerate and double-degenerate scenarios for the progenitor system.

  8. Particle contamination control in plasma processing: Building-in reliability for semiconductor fabrication

    SciTech Connect (OSTI)

    Selwyn, G.S.

    1995-12-31

    Plasma processing is used for {approximately}35% of the process steps required for semiconductor manufacturing. Recent studies have shown that plasma processes create the greatest amount of contaminant dust of all the manufacturing steps required for device fabrication. Often, the level of dust in a plasma process tool exceeds the cleanroom by several orders of magnitude. Particulate contamination generated in a plasma tool can result in reliability problems as well as device failure. Inter-level wiring shorts different levels of metallization on a device is a common result of plasma particulate contamination. We have conducted a thorough study of the physics and chemistry involved in particulate formation and transport in plasma tools. In-situ laser light scattering (LLS) is used for real-time detection of the contaminant dust. The results of this work are highly surprising: all plasmas create dust; the dust can be formed by homogeneous as well as heterogeneous chemistry; this dust is charged and suspended in the plasma; additionally, it is transported to favored regions of the plasma, such as those regions immediately above wafers. Fortunately, this work has also led to a novel means of controlling and eliminating these unwanted contaminants: electrostatic {open_quotes}drainpipes{close_quotes} engineered into the electrode by means of specially designed grooves. These channel the suspended particles out of the plasma and into the pump port before they can fall onto the wafer.

  9. Contributed papers Study of gas-fluidization dynamics with laser-polarized 129

    E-Print Network [OSTI]

    Walsworth, Ronald L.

    commercial fluidized beds operate in the bubbling fluidization regime, in which gas-filled particle, Amherst, MA 01003, USA Abstract We report initial NMR studies of gas dynamics in a particle bed fluidized characteristics: gas exchange between the bubble and emulsion phases and the gas velocity distribution in the bed

  10. Fundamental mechanisms in flue gas conditioning

    SciTech Connect (OSTI)

    Snyder, T.R.; Bush, P.V.

    1993-01-20

    We performed a wide variety of laboratory analyses during the past quarter. As with most of the work we performed during the previous quarter, our recent efforts were primarily directed toward the determination of the effects of adsorbed water on the cohesivity and tensile strength of powders. We also continued our analyses of dust cake ashes that have had the soluble compounds leached from their particle surfaces by repeated washings with water. Our analyses of leached and unleached dust cake ashes continued to provide some interesting insights into effects that compounds adsorbed on surfaces of ash particles can have on bulk ash behavior. As suggested by our literature review, our data indicate that water adsorption depends on particle morphology and on surface chemistry. Our measurements of tensile strength show, that for many of the samples we have analyzed a relative minimum in tensile strength exists for samples conditioned and tested at about 30% relative humidity. In our examinations of the effects of water conditioning on sample cohesivity, we determined that in the absence of absorption of water into the interior of the particles, cohesivity usually increases sharply when environments having relative humidities above 75% are used to condition and test the samples. Plans are under way to condition selected samples with (NH[sub 4])[sub 2]SO[sub 4], NH[sub 4]HSO[sub 4], CaCl[sub 2], organosiloxane, and SO[sub 3]. Pending approval, we will begin these conditioning experiments, and subsequent analyses of the conditioned samples.

  11. Naked singularity formation for higher dimensional inhomogeneous dust collapse

    E-Print Network [OSTI]

    Ujjal Debnath; Subenoy Chakraborty

    2003-02-28

    We investigate the occurrence and nature of a naked singularity in the gravitational collapse of an inhomogeneous dust cloud described by higher dimensional Tolman-Bondi space-time. The naked singularities are found to be gravitationally strong.

  12. Environmental Scientists Find Antibiotics, Bacteria, Resistance Genes in Feedlot Dust

    E-Print Network [OSTI]

    Rock, Chris

    Environmental Scientists Find Antibiotics, Bacteria, Resistance Genes in Feedlot Dust :: Texas Tech Today http://today.ttu.edu/2015/01/environmental-scientists-find-antibiotics Print Email + Font - Font Environmental Scientists Find Antibiotics, Bacteria, Resistance Genes

  13. Evaluation and recommendations for reduction of a silica dust exposure 

    E-Print Network [OSTI]

    Gruben, Raymond L

    2000-01-01

    A brick cutting task was identified as a job with a potential overexposure to crystalline silica dust. A sampling plan was proposed and implemented. Both the NIOSH approved method, using cyclone filters to select out ...

  14. SHAPE AND SIZE FROM THE MIST A Deformable Model for Particle Characterization

    E-Print Network [OSTI]

    , or particles in gas, such as the coal particles from a power plant. A vision-based system can pro- vide of the particles de- pends on the optical properties of the camera setup, 1PROVAEN ­ Process Visualisation, and the physical reflectance properties of the particles. The depth of field of the camera optics is narrow

  15. Gas Mask 

    E-Print Network [OSTI]

    Unknown

    2011-09-05

    The gas industry fostered more efficient energy utilization long before the idea of energy conservation became fashionable. It became apparent in the late '60's that misguided Federal Legislation was discouraging necessary search for new gas...

  16. THE TRANSIT LIGHT CURVE OF AN EXOZODIACAL DUST CLOUD

    SciTech Connect (OSTI)

    Stark, Christopher C.

    2011-10-15

    Planets embedded within debris disks gravitationally perturb nearby dust and can create clumpy, azimuthally asymmetric circumstellar ring structures that rotate in lock with the planet. The Earth creates one such structure in the solar zodiacal dust cloud. In an edge-on system, the dust 'clumps' periodically pass in front of the star as the planet orbits, occulting and forward-scattering starlight. In this paper, we predict the shape and magnitude of the corresponding transit signal. To do so, we model the dust distributions of collisional, steady-state exozodiacal clouds perturbed by planetary companions. We examine disks with dusty ring structures formed by the planet's resonant trapping of in-spiraling dust for a range of planet masses and semi-major axes, dust properties, and disk masses. We synthesize edge-on images of these models and calculate the transit signatures of the resonant ring structures. The transit light curves created by dusty resonant ring structures typically exhibit two broad transit minima that lead and trail the planetary transit. We find that Jupiter-mass planets embedded within disks hundreds of times denser than our zodiacal cloud can create resonant ring structures with transit depths up to {approx}10{sup -4}, possibly detectable with Kepler. Resonant rings produced by planets more or less massive than Jupiter produce smaller transit depths. Observations of these transit signals may provide upper limits on the degree of asymmetry in exozodiacal clouds.

  17. Gas separating

    DOE Patents [OSTI]

    Gollan, Arye Z.

    1990-12-25

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing.

  18. Gas separating

    DOE Patents [OSTI]

    Gollan, Arye (Newton, MA)

    1988-01-01

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing.

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

    E-Print Network [OSTI]

    Pierce, J. R.

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

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

    SciTech Connect (OSTI)

    Weinberger, A. J.; Becklin, E. E.; Zuckerman, B.; Song, I. E-mail: becklin@astro.ucla.edu E-mail: song@uga.edu

    2011-01-10

    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.

  1. Fermilab | Science | Particle Physics 101 | How Particle Physics Discovery

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDid you not find whatGasEnergyfeature photo featureParticle Physics 101Ask

  2. Fermilab | Science | Particle Physics 101 | Worldwide Particle Physics

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDid you not find whatGasEnergyfeature photo featureParticle PhysicsSpace

  3. Fermilab | Science | Particle Physics | Benefits of Particle Physics

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDid you not find whatGasEnergyfeature photo featureParticle

  4. Fermilab | Science | Particle Physics | More fundamental particles and

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDid you not find whatGasEnergyfeature photo featureParticleDark

  5. Process to make structured particles

    DOE Patents [OSTI]

    Knapp, Angela Michelle; Richard, Monique N; Luhrs, Claudia; Blada, Timothy; Phillips, Jonathan

    2014-02-04

    Disclosed is a process for making a composite material that contains structured particles. The process includes providing a first precursor in the form of a dry precursor powder, a precursor liquid, a precursor vapor of a liquid and/or a precursor gas. The process also includes providing a plasma that has a high field zone and passing the first precursor through the high field zone of the plasma. As the first precursor passes through the high field zone of the plasma, at least part of the first precursor is decomposed. An aerosol having a second precursor is provided downstream of the high field zone of the plasma and the decomposed first material is allowed to condense onto the second precursor to from structured particles.

  6. Shock processing of interstellar dust and polycyclic aromatic hydrocarbons in the supernova remnant N132D

    E-Print Network [OSTI]

    A. Tappe; J. Rho; W. T. Reach

    2006-09-06

    We observed the oxygen-rich Large Magellanic Cloud (LMC) supernova remnant N132D (SNR 0525-69.6), using all instruments onboard the Spitzer Space Telescope, IRS, IRAC, and MIPS (Infrared Spectrograph, Infrared Array Camera, Multiband Imaging Photometer for Spitzer). The 5-40 micron IRS spectra toward the southeastern shell of the remnant show a steeply rising continuum with [NeIII] and [OIV] as well as PAH emission. We also present the spectrum of a fast moving ejecta knot, previously detected at optical wavelengths, which is dominated by strong [NeIII] and [OIV] emission lines. We interpret the continuum as thermal emission from swept-up, shock-heated dust grains in the expanding shell of N132D, which is clearly visible in the MIPS 24 micron image. A 15-20 micron emission hump appears superposed on the dust continuum, and we attribute this to PAH C-C-C bending modes. We also detect the well-known 11.3 micron PAH C-H bending feature, and find the integrated strength of the 15-20 micron hump about a factor of seven stronger than the 11.3 micron band in the shell of the remnant. IRAC 3-9 micron images do not show clear evidence of large-scale, shell-like emission from the remnant, partly due to confusion with the ambient ISM material. However, we identified several knots of shocked interstellar gas based on their distinct infrared colors. We discuss the bright infrared continuum and the polycyclic aromatic hydrocarbon features with respect to dust processing in young supernova remnants.

  7. Capture of particles of dust by convective flow Dmitry V. Lyubimov

    E-Print Network [OSTI]

    Straube, Arthur V.

    , University of Potsdam, Am Neuen Palais 10, PF 601553, D-14415 Potsdam, Germany and CFD Laboratory, Institute of Theoretical Physics, Perm State University, Bukirev 15, 614990 Perm, Russia and CFD Laboratory, Institute is essential in lowering fuel consumption during combustion of liquid fuels. In biology, recent developments

  8. Sorption Hysteresis of Benzene in Charcoal Particles

    E-Print Network [OSTI]

    Muzzio, Fernando J.

    Sorption Hysteresis of Benzene in Charcoal Particles W A S H I N G T O N J . B R A I D A , , J O (benzene) in water to a maple- wood charcoal prepared by oxygen-limited pyrolysis at 673 K. Gas adsorption m2/g, and appreciable porosity in ultramicropores Benzene sorption- desorption conditions

  9. Fermilab | Science | Particle Physics 101

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDid you not find whatGasEnergyfeature photo featureParticle Physics 101

  10. Fermilab | Science | Particle Physics | Muons

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDid you not find whatGasEnergyfeature photo featureParticleDarkMuons photo

  11. Fermilab | Science | Particle Physics | Neutrinos

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDid you not find whatGasEnergyfeature photo featureParticleDarkMuons

  12. Membrane based apparatus for measurement of volatile particles

    DOE Patents [OSTI]

    Cheng, Meng-Dawn; Allman, Steve L.

    2014-07-08

    A vapor particle separator including a temperature controlled chamber for desorbing vapors from the particulates of an exhaust gas and a separation chamber including a micro porous membrane. The micro porous membrane provides an interface between at least one particle passageway and at least one vapor passageway through the separation chamber. The particle passageway extends from an entrance to the separation chamber to a particle exit from the separation chamber. The vapor passageway extends from the micro-porous membrane to a vapor exit from the separation chamber that is separate from the particle exit from the separation chamber.

  13. Intrinsic fluctuations of dust grain charge in multi-component plasmas

    SciTech Connect (OSTI)

    Shotorban, B.

    2014-03-15

    A master equation is formulated to model the states of the grain charge in a general multi-component plasma, where there are electrons and various kinds of positive or negative ions that are singly or multiply charged. A Fokker-Planck equation is developed from the master equation through the system-size expansion method. The Fokker-Planck equation has a Gaussian solution with a mean and variance governed by two initial-value differential equations involving the rates of the attachment of ions and electrons to the dust grain. Also, a Langevin equation and a discrete stochastic method are developed to model the time variation of the grain charge. Grain charging in a plasma containing electrons, protons, and alpha particles with Maxwellian distributions is considered as an example problem. The Gaussian solution is in very good agreement with the master equation solution numerically obtained for this problem.

  14. Laser particle sorter

    DOE Patents [OSTI]

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

    1987-11-30

    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.

  15. Protection of lithographic components from particle contamination

    DOE Patents [OSTI]

    Klebanoff, Leonard E. (San Ramon, CA); Rader, Daniel J. (Lafayette, CA)

    2000-01-01

    A system that employs thermophoresis to protect lithographic surfaces from particle deposition and operates in an environment where the pressure is substantially constant and can be sub-atmospheric. The system (thermophoretic pellicle) comprises an enclosure that surrounds a lithographic component whose surface is being protected from particle deposition. The enclosure is provided with means for introducing a flow of gas into the chamber and at least one aperture that provides for access to the lithographic surface for the entry and exit of a beam of radiation, for example, and further controls gas flow into a surrounding low pressure environment such that a higher pressure is maintained within the enclosure and over the surface being protected. The lithographic component can be heated or, alternatively the walls of the enclosure can be cooled to establish a temperature gradient between the surface of the lithographic component and the walls of the enclosure, thereby enabling the thermophoretic force that resists particle deposition.

  16. New Particle Formation Study Final Campaign Report

    SciTech Connect (OSTI)

    Smith, JN; McMurry, PH

    2015-01-01

    The scientific foci of the New Particle Formation Study were the formation and evolution of atmospheric aerosols and the impacts of newly formed particles on cloud processes. Specifically, we planned to: (1) to identify the species and mechanisms responsible for the initial steps of new particle formation, i.e., the formation of thermodynamically stable clusters; (2) investigate the role of acid-base chemistry in new particle growth through measurements of ammonia and amines as well as organic and inorganic acids in both atmospheric nanoparticles and the gas phase; (3) investigate the contribution of other surface area or volume-controlled processes to nanoparticle formation and growth; (4) create a comprehensive dataset related to new particle formation and growth that can be used as input for our own thermodynamic models as well as the modeling efforts by our Department of Energy (DOE) Aerosol Life Cycle working group collaborators; (5) characterize the increase of the number and activity of cloud condensation nuclei (CCN) due to particle formation and growth; (6) determine the regional extent of new particle formation to address the role that atmospheric transport plays in determining the impacts, if any, of new particle formation on cloud number and properties.

  17. Evidence for a Global Warming at the Termination I Boundary and Its Possible Cosmic Dust Cause

    E-Print Network [OSTI]

    Paul A. LaViolette

    2005-03-18

    A comparison of northern and southern hemispheric paleotemperature profiles suggests that the Bolling-Allerod Interstadial, Younger Dryas stadial, and subsequent Preboreal warming which occurred at the end of the last ice age were characterized by temperatures that changed synchronously in various parts of the world, implying that these climatic oscillations were produced by significant changes in the Earth's energy balance. These globally coordinated oscillations are not easily explained by ocean current mechanisms such as bistable flipping of ocean deep-water production or regional temperature changes involving the NW/SE migration of the North Atlantic polar front. They also are not accounted for by Earth orbital changes in seasonality or by increases in atmospheric CO-2 or CH-4. On the other hand, evidence of an elevated cosmic ray flux and of a major interstellar dust incursion around 15,800 years B.P. suggest that a cosmic ray wind driven incursion of interstellar dust and gas may have played a key role through its activation of the Sun and alteration of light transmission through the interplanetary medium.

  18. Dynamic Particle Coupling for GPU-based Fluid Simulation

    E-Print Network [OSTI]

    Blanz, Volker

    -vi ¯j 2 W( Pi -Pj ,h). Here pj = k( ¯j - 0) is the pressure with gas constant k and rest density 0 for modeling dynamic particle coupling solely based on individual particle contributions. This technique does and µ is the fluid viscosity constant. To model the surface tension, M¨uller et.al. [MCG03] use the so

  19. Thermodynamics of resonances and blurred particles

    E-Print Network [OSTI]

    D. N. Voskresensky

    2008-04-10

    Exact and approximate expressions for thermodynamic characteristics of heated matter, which consists of particles with finite mass-widths, are constructed. They are expressed in terms of Fermi/Bose distributions and spectral functions, rather than in terms of more complicated combinations between real and imaginary parts of the self-energies of different particle species. Therefore thermodynamically consistent approximate treatment of systems of particles with finite mass-widths can be performed, provided spectral functions of particle species are known. Approximation of the free resonance gas at low densities is studied. Simple ansatz for the energy dependence of the spectral function is suggested that allows to fulfill thermodynamical consistency conditions. On examples it is shown that a simple description of dense systems of interacting particle species can be constructed, provided some species can be treated in the quasiparticle approximation and others as particles with widths. The interaction affects quasiparticle contributions, whereas particles with widths can be treated as free. Example is considered of a hot gas of heavy fermions strongly interacting with light bosons, both species with zero chemical potentials. The density of blurred fermions is dramatically increased for high temperatures compared to the standard Boltzmann value. The system consists of boson quasiparticles (with effective masses) interacting with fermion -- antifermion blurs. In thermodynamical values interaction terms partially compensate each other. Thereby, in case of a very strong coupling between species thermodynamical quantities of the system, like the energy, pressure and entropy, prove to be such as for the quasi-ideal gas mixture of quasi-free fermion blurs and quasi-free bosons.

  20. THE MASS-LOSS RETURN FROM EVOLVED STARS TO THE LARGE MAGELLANIC CLOUD. II. DUST PROPERTIES FOR OXYGEN-RICH ASYMPTOTIC GIANT BRANCH STARS

    SciTech Connect (OSTI)

    Sargent, Benjamin A.; Meixner, M.; Gordon, Karl D. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Srinivasan, S. [Institut d'Astrophysique de Paris, 98 bis, Boulevard Arago, Paris 75014 (France); Kemper, F.; Woods, Paul M. [Jodrell Bank Centre for Astrophysics, Alan Turing Building, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Tielens, A. G. G. M. [Leiden Observatory, P.O. Box 9513, NL-2300 RA Leiden (Netherlands); Speck, A. K. [Physics and Astronomy Department, University of Missouri, Columbia, MO 65211 (United States); Matsuura, M. [Institute of Origins, Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Bernard, J.-Ph. [Centre d'Etude Spatiale des Rayonnements, 9 Av. du Colonel Roche, BP 44346, 31028 Toulouse Cedex 4 (France); Hony, S. [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot DAPNIA/Service d'Astrophysique Bat. 709, CEA-Saclay F-91191 Gif-sur-Yvette Cedex (France); Indebetouw, R. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States); Marengo, M. [Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Sloan, G. C., E-mail: sargent@stsci.ed [Department of Astronomy, Cornell University, Ithaca, NY 14853 (United States)

    2010-06-10

    We model multi-wavelength broadband UBVIJHK{sub s} and Spitzer IRAC and MIPS photometry and Infrared Spectrograph spectra from the SAGE and SAGE-Spectroscopy observing programs of two oxygen-rich asymptotic giant branch (O-rich AGB) stars in the Large Magellanic Cloud (LMC) using radiative transfer (RT) models of dust shells around stars. We chose a star from each of the bright and faint O-rich AGB populations found by earlier studies of the SAGE sample in order to derive a baseline set of dust properties to be used in the construction of an extensive grid of RT models of the O-rich AGB stars found in the SAGE surveys. From the bright O-rich AGB population, we chose HV 5715, and from the faint O-rich AGB population we chose SSTISAGE1C J052206.92-715017.6 (SSTSAGE052206). We found the complex indices of refraction of oxygen-deficient silicates from Ossenkopf et al. and a power law with exponential decay grain size distribution like what Kim et al. used but with {gamma} of -3.5, a {sub min} of 0.01 {mu}m, and a {sub 0} of 0.1 {mu}m to be reasonable dust properties for these models. There is a slight indication that the dust around the faint O-rich AGB may be more silica-rich than that around the bright O-rich AGB. Simple models of gas emission suggest a relatively extended gas envelope for the faint O-rich AGB star modeled, consistent with the relatively large dust shell inner radius for the same model. Our models of the data require the luminosity of SSTSAGE052206 and HV 5715 to be {approx}5100 L {sub sun} and {approx}36,000 L {sub sun}, respectively. This, combined with the stellar effective temperatures of 3700 K and 3500 K, respectively, that we find best fit the optical and near-infrared data, suggests stellar masses of {approx}3 M {sub sun} and {approx}7 M {sub sun}. This, in turn, suggests that HV 5715 is undergoing hot-bottom burning and that SSTSAGE052206 is not. Our models of SSTSAGE052206 and HV 5715 require dust shells of inner radius {approx}17 and {approx}52 times the stellar radius, respectively, with dust temperatures there of 900 K and 430 K, respectively, and with optical depths at 10 {mu}m through the shells of 0.095 and 0.012, respectively. The models compute the dust mass-loss rates for the two stars to be 2.0 x 10{sup -9} M{sub sun} yr{sup -1} and 2.3 x 10{sup -9} M{sub sun} yr{sup -1}, respectively. When a dust-to-gas mass ratio of 0.002 is assumed for SSTSAGE052206 and HV 5715, the dust mass-loss rates imply total mass-loss rates of 1.0 x 10{sup -6} M{sub sun} yr{sup -1} and 1.2 x 10{sup -6} M{sub sun} yr{sup -1}, respectively. These properties of the dust shells and stars, as inferred from our models of the two stars, are found to be consistent with properties observed or assumed by detailed studies of other O-rich AGB stars in the LMC and elsewhere.

  1. CHARACTERIZING THE DUST COMA OF COMET C/2012 S1 (ISON) AT 4.15 AU FROM THE SUN

    SciTech Connect (OSTI)

    Li, Jian-Yang; Kelley, Michael S. P.; Farnham, Tony L.; A'Hearn, Michael F.; Kolokolova, Ludmilla; Knight, Matthew M.; Weaver, Harold A.; Mutchler, Max J.; Lamy, Philippe; Toth, Imre E-mail: msk@astro.umd.edu E-mail: ma@astro.umd.edu E-mail: knight@lowell.edu E-mail: mutchler@stsci.edu E-mail: tothi@konkoly.hu

    2013-12-10

    We report results from broadband visible images of comet C/2012 S1 (ISON) obtained with the Hubble Space Telescope Wide Field Camera 3 on 2013 April 10. C/ISON's coma brightness follows a 1/? (where ? is the projected distance from the nucleus) profile out to 5000 km, consistent with a constant speed dust outflow model. The turnaround distance in the sunward direction suggests that the dust coma is composed of sub-micron-sized particles emitted at speeds of tens of m s{sup –1}. A(?)f?, which is commonly used to characterize the dust production rate, was 1340 and 1240 cm in the F606W and F438W filters, respectively, in apertures <1.''6 in radius. The dust colors are slightly redder than solar, with a slope of 5.0% ± 0.2% per 100 nm, increasing to >10% per 100 nm 10,000 km down the tail. The colors are similar to those of comet C/1995 O1 (Hale-Bopp) and other long-period comets, but somewhat bluer than typical values for short-period comets. The spatial color variations are also reminiscent of C/Hale-Bopp. A sunward jet is visible in enhanced images, curving to the north and then tailward in the outer coma. The 1.''6 long jet is centered at a position angle of 291°, with an opening angle of ?45°. The jet morphology remains unchanged over 19 hr of our observations, suggesting that it is near the rotational pole of the nucleus, and implying that the pole points to within 30° of (R.A., decl.) = (330°, 0°). This pole orientation indicates a high obliquity of 50°-80°.

  2. Associations between bacterial communities of house dust and infant gut

    SciTech Connect (OSTI)

    Konya, T.; Koster, B.; Maughan, H.; Escobar, M.; Azad, M.B.; Guttman, D.S.; Sears, M.R.; Becker, A.B.; Brook, J.R.; Takaro, T.K.; Kozyrskyj, A.L.; Scott, J.A.

    2014-05-01

    The human gut is host to a diverse and abundant community of bacteria that influence health and disease susceptibility. This community develops in infancy, and its composition is strongly influenced by environmental factors, notably perinatal anthropogenic exposures such as delivery mode (Cesarean vs. vaginal) and feeding method (breast vs. formula); however, the built environment as a possible source of exposure has not been considered. Here we report on a preliminary investigation of the associations between bacteria in house dust and the nascent fecal microbiota from 20 subjects from the Canadian Healthy Infant Longitudinal Development (CHILD) Study using high-throughput sequence analysis of portions of the 16S rRNA gene. Despite significant differences between the dust and fecal microbiota revealed by Nonmetric Multidimensional Scaling (NMDS) analysis, permutation analysis confirmed that 14 bacterial OTUs representing the classes Actinobacteria (3), Bacilli (3), Clostridia (6) and Gammaproteobacteria (2) co-occurred at a significantly higher frequency in matched dust–stool pairs than in randomly permuted pairs, indicating an association between these dust and stool communities. These associations could indicate a role for the indoor environment in shaping the nascent gut microbiota, but future studies will be needed to confirm that our findings do not solely reflect a reverse pathway. Although pet ownership was strongly associated with the presence of certain genera in the dust for dogs (Agrococcus, Carnobacterium, Exiguobacterium, Herbaspirillum, Leifsonia and Neisseria) and cats (Escherichia), no clear patterns were observed in the NMDS-resolved stool community profiles as a function of pet ownership.

  3. First-principles investigations of Ni3Al(111) and NiAl(110) surfaces at metal dusting conditions

    SciTech Connect (OSTI)

    Saadi, Souheil

    2011-03-01

    We investigate the structure and surface composition of the {gamma}{prime}-Ni{sub 3}Al(111) and {beta}-NiAl(110) alloy surfaces at conditions relevant for metal dusting corrosion related to catalytic steam reforming of natural gas. In regular service as protective coatings, nickel-aluminum alloys are protected by an oxide scale, but in case of oxide scale spallation, the alloy surface may be directly exposed to the reactive gas environment and vulnerable to metal dusting. By means of density functional theory and thermochemical calculations for both the Ni{sub 3}Al and NiAl surfaces, the conditions under which CO and OH adsorption is to be expected and under which it is inhibited, are mapped out. Because CO and OH are regarded as precursors for nucleating graphite or oxide on the surfaces, phase diagrams for the surfaces provide a simple description of their stability. Specifically, this study shows how the CO and OH coverages depend on the steam to carbon ratio (S/C) in the gas and thereby provide a ranking of the carbon limits on the different surface phases.

  4. Phenomena of spin rotation and oscillation of particles (atoms, molecules) containing in a trap blowing on by wind of high energy particles in storage ring - new method of measuring of spin-dependent part of zero-angle coherent scattering amplitude

    E-Print Network [OSTI]

    Vladimir Baryshevsky

    2002-12-09

    New experiment arrangement to study spin rotation and oscillation of particles of gas target through which beam of high energy particles passes is discussed. Such experiment arrangement make it realizable for storage ring and allows to study zero-angle scattering amplitude at highest possible energies. Life-time of particle beam in storage ring can reach several hours and even days. Life-time of particle in gas target (gas trap) is long too. Particles circulate in storage ring with frequency $\

  5. Gas separating

    DOE Patents [OSTI]

    Gollan, A.Z.

    1990-12-25

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.

  6. Gas separating

    DOE Patents [OSTI]

    Gollan, A.

    1988-03-29

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.

  7. A New Determination of the Binding Energy of Atomic Oxygen on Dust Grain Surfaces: Experimental Results and Simulations

    E-Print Network [OSTI]

    He, Jiao; Hopkins, Tyler; Vidali, Gianfranco; Kaufman, Michael J

    2015-01-01

    The energy to desorb atomic oxygen from an interstellar dust grain surface, $E_{\\rm des}$, is an important controlling parameter in gas-grain models; its value impacts the temperature range over which oxygen resides on a dust grain. However, no prior measurement has been done of the desorption energy. We report the first direct measurement of $E_{\\rm des}$ for atomic oxygen from dust grain analogs. The values of $E_{\\rm des}$ are $1660\\pm 60$~K and $1850\\pm 90$~K for porous amorphous water ice and for a bare amorphous silicate film, respectively, or about twice the value previously adopted in simulations of the chemical evolution of a cloud. We use the new values to study oxygen chemistry as a function of depth in a molecular cloud. For $n=10^4$ cm$^{-3}$ and $G_0$=10$^2$ ($G_0$=1 is the average local interstellar radiation field), the main result of the adoption of the higher oxygen binding energy is that H$_2$O can form on grains at lower visual extinction $A_{\\rm V}$, closer to the cloud surface. A higher ...

  8. Dust temperature and CO-to-H2 conversion factor variations in the SFR-M* plane

    E-Print Network [OSTI]

    Magnelli, B; Lutz, D; Tacconi, L J; Berta, S; Bournaud, F; Charmandaris, V; Dannerbauer, H; Elbaz, D; Förster-Schreiber, N M; Graciá-Carpio, J; Ivison, R; Maiolino, R; Nordon, R; Popesso, P; Rodighiero, G; Santini, P; Wuyts, S

    2012-01-01

    Deep Herschel imaging and 12CO(2-1) line luminosities from the IRAM PdBI are combined for a sample of 17 galaxies at z>1 from the GOODS-N field. The sample includes galaxies both on and above the main sequence (MS) traced by star-forming galaxies in the SFR-M* plane. The far-infrared data are used to derive dust masses, Mdust. Combined with an empirical prescription for the dependence of the gas-to-dust ratio on metallicity (GDR), the CO luminosities and Mdust values are used to derive for each galaxy the CO-to-H2 conversion factor, alpha_co. Like in the local Universe, the value of alpha_co is a factor of ~5 smaller in starbursts compared to normal star-forming galaxies (SFGs). We also uncover a relation between alpha_co and dust temperature (Tdust; alpha_co decreasing with increasing Tdust) as obtained from modified blackbody fits to the far-infrared data. While the absolute normalization of the alpha_co(Tdust) relation is uncertain, the global trend is robust against possible systematic biases in the deter...

  9. particle physics 2009Highlights

    E-Print Network [OSTI]

    Report particle physics 2009ª #12;2 | Contents #12;Contents | 3 contentsª º introduction 4 º News;Introduction | 5 projects, (ii) coordination of national particle physics activities and (iii) reaching outparticle physics 2009ªHighlights and Annual Report Accelerators | Photon Science | Particle Physics

  10. Dispersion relations of externally and thermally excited dust lattice modes in 2D complex plasma crystals

    SciTech Connect (OSTI)

    Yang Xuefeng; Cui Jian; Zhang Yuan [School of Mathematical Sciences, Dalian University of Technology, Dalian 116024 (China); Liu Yue [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2012-07-15

    The dispersion relations of the externally and thermally (naturally) excited dust lattice modes (both longitudinal and transverse) in two-dimensional Debye-Yukawa complex plasma crystals are investigated. The dispersion relations are calculated numerically by taking the neutral gas damping effects into account and the numerical results are in agreement with the experimental data given by Nunomura et al.[Phys. Rev. E 65, 066402 (2002)]. It is found that for the mode excited by an external disturbance with a real frequency, the dispersion properties are changed at a critical frequency near where the group velocity of the mode goes to zero. Therefore, the high frequency branch with negative dispersion cannot be reached. In contrast, for the thermally excited mode, the dispersion curve can extend all the way to the negative dispersion region, while a 'cut-off' wave number exists at the long wavelength end of the dispersion in the transverse mode.

  11. Lithium Wall Conditioning And Surface Dust Detection On NSTX

    SciTech Connect (OSTI)

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

    2011-05-23

    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

  12. Gas distributor for fluidized bed coal gasifier

    DOE Patents [OSTI]

    Worley, Arthur C. (Mt. Tabor, NJ); Zboray, James A. (Irvine, CA)

    1980-01-01

    A gas distributor for distributing high temperature reaction gases to a fluidized bed of coal particles in a coal gasification process. The distributor includes a pipe with a refractory reinforced lining and a plurality of openings in the lining through which gas is fed into the bed. These feed openings have an expanding tapered shape in the downstream or exhaust direction which aids in reducing the velocity of the gas jets as they enter the bed.

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

    E-Print Network [OSTI]

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

    2006-09-08

    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.

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

    E-Print Network [OSTI]

    Tamanai, A; Blum, J; Meeus, G

    2006-01-01

    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.

  15. Metal oxide membranes for gas separation

    DOE Patents [OSTI]

    Anderson, Marc A. (Madison, WI); Webster, Elizabeth T. (Madison, WI); Xu, Qunyin (Plainsboro, NJ)

    1994-01-01

    A method for permformation of a microporous ceramic membrane onto a porous support includes placing a colloidal suspension of metal oxide particles on one side of the porous support and exposing the other side of the porous support to a drying stream of gas or a reactive gas stream so that the particles are deposited on the drying side of the support as a gel. The gel so deposited can be sintered to form a supported ceramic membrane having mean pore sizes less than 30 Angstroms and useful for ultrafiltration, reverse osmosis, or gas separation.

  16. Metal oxide membranes for gas separation

    DOE Patents [OSTI]

    Anderson, M.A.; Webster, E.T.; Xu, Q.

    1994-08-30

    A method for formation of a microporous ceramic membrane onto a porous support includes placing a colloidal suspension of metal oxide particles on one side of the porous support and exposing the other side of the porous support to a drying stream of gas or a reactive gas stream so that the particles are deposited on the drying side of the support as a gel. The gel so deposited can be sintered to form a supported ceramic membrane having mean pore sizes less than 30 Angstroms and useful for ultrafiltration, reverse osmosis, or gas separation. 4 figs.

  17. Chemoresistive gas sensor

    DOE Patents [OSTI]

    Hirschfeld, T.B.

    1987-06-23

    A chemoresistive gas sensor is provided which has improved sensitivity. A layer of organic semiconductor is disposed between two electrodes which, in turn, are connected to a voltage source. High conductivity material is dispersed within the layer of organic semiconductor in the form of very small particles, or islands. The average interisland spacing is selected so that the predominant mode of current flow is by way of electron funneling. Adsorption of gaseous contaminant onto the layer of organic semiconductor modulates the tunneling current in a quantitative manner. 2 figs.

  18. Testing your home for lead in paint, dust, and soil

    SciTech Connect (OSTI)

    1998-10-01

    This publication is for anyone who is considering having a home or residence tested for lead in paint, dust, or soil by a professional. It explains the technical aspects of lead testing without overwhelming the reader. The first section tells why you would test for lead, the approaches for testing for lead, and what information you will get from each approach. The second section answers specific questions about how paint, soil, and dust sampling are conducted by the professional in your home. Finally, the last section answers other questions about testing, including questions about home test kits and testing of water and ceramics.

  19. Sub-micron particle sampler apparatus

    DOE Patents [OSTI]

    Gay, Don D. (Aiken, SC); McMillan, William G. (Ulmers, SC)

    1987-01-01

    Apparatus and method steps for collecting sub-micron sized particles include a collection chamber and cryogenic cooling. The cooling is accomplished by coil tubing carrying nitrogen in liquid form, with the liquid nitrogen changing to the gas phase before exiting from the collection chamber in the tubing. Standard filters are used to filter out particles of diameter greater than or equal to 0.3 microns; however the present invention is used to trap particles of less than 0.3 micron in diameter. A blower draws air to said collection chamber through a filter which filters particles with diameters greater than or equal to 0.3 micron. The air is then cryogenically cooled so that moisture and sub-micron sized particles in the air condense into ice on the coil. The coil is then heated so that the ice melts, and the liquid is then drawn off and passed through a Buchner funnel where the liquid is passed through a Nuclepore membrane. A vacuum draws the liquid through the Nuclepore membrane, with the Nuclepore membrane trapping sub-micron sized particles therein. The Nuclepore membrane is then covered on its top and bottom surfaces with sheets of Mylar.RTM. and the assembly is then crushed into a pellet. This effectively traps the sub-micron sized particles for later analysis.

  20. Method for sampling sub-micron particles

    DOE Patents [OSTI]

    Gay, Don D. (Aiken, SC); McMillan, William G. (Ulmers, SC)

    1985-01-01

    Apparatus and method steps for collecting sub-micron sized particles include a collection chamber and cryogenic cooling. The cooling is accomplished by coil tubing carrying nitrogen in liquid form, with the liquid nitrogen changing to the gas phase before exiting from the collection chamber in the tubing. Standard filters are used to filter out particles of diameter greater than or equal to 0.3 microns; however the present invention is used to trap particles of less than 0.3 micron in diameter. A blower draws air to said collection chamber through a filter which filters particles with diameters greater than or equal to 0.3 micron. The air is then cryogenically cooled so that moisture and sub-micron sized particles in the air condense into ice on the coil. The coil is then heated so that the ice melts, and the liquid is then drawn off and passed through a Buchner funnel where the liquid is passed through a Nuclepore membrane. A vacuum draws the liquid through the Nuclepore membrane, with the Nuclepore membrane trapping sub-micron sized particles therein. The Nuclepore membrane is then covered on its top and bottom surfaces with sheets of Mylar.RTM. and the assembly is then crushed into a pellet. This effectively traps the sub-micron sized particles for later analysis.

  1. Adhesive particle shielding

    DOE Patents [OSTI]

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

    2009-01-06

    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.

  2. Method for improved gas-solids separation

    DOE Patents [OSTI]

    Kusik, Charles L. (Lincoln, MA); He, Bo X. (Newton, MA)

    1990-01-01

    Methods are disclosed for the removal of particulate solids from a gas stream at high separation efficiency, including the removal of submicron size particles. The apparatus includes a cyclone separator type of device which contains an axially mounted perforated cylindrical hollow rotor. The rotor is rotated at high velocity in the same direction as the flow of an input particle-laden gas stream to thereby cause enhanced separation of particulate matter from the gas stream in the cylindrical annular space between the rotor and the sidewall of the cyclone vessel. Substantially particle-free gas passes through the perforated surface of the spinning rotor and into the hollow rotor, from when it is discharged out of the top of the apparatus. Separated particulates are removed from the bottom of the vessel.

  3. Method for improved gas-solids separation

    DOE Patents [OSTI]

    Kusik, C.L.; He, B.X.

    1990-11-13

    Methods are disclosed for the removal of particulate solids from a gas stream at high separation efficiency, including the removal of submicron size particles. The apparatus includes a cyclone separator type of device which contains an axially mounted perforated cylindrical hollow rotor. The rotor is rotated at high velocity in the same direction as the flow of an input particle-laden gas stream to thereby cause enhanced separation of particulate matter from the gas stream in the cylindrical annular space between the rotor and the sidewall of the cyclone vessel. Substantially particle-free gas passes through the perforated surface of the spinning rotor and into the hollow rotor, from where it is discharged out of the top of the apparatus. Separated particulates are removed from the bottom of the vessel. 4 figs.

  4. A New Facility for Studying Shock Wave Passage over Dust Layers 

    E-Print Network [OSTI]

    Marks, Brandon

    2013-05-30

    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 of numerical predictions of this phenomenon. A...

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

    E-Print Network [OSTI]

    Ai, Ning, 1978-

    2003-01-01

    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 ...

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

    E-Print Network [OSTI]

    Kostinski, Alex

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

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

    E-Print Network [OSTI]

    Ridley, David Andrew

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

  8. Techniques For Injection Of Pre-Charaterized Dust Into The Scrape...

    Office of Scientific and Technical Information (OSTI)

    For Injection Of Pre-Charaterized Dust Into The Scrape Off Layer Of Fusion Plasma Introduction of micron-sized dust into the scrape-off layer (SOL) of a plasma has recently...

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

    E-Print Network [OSTI]

    Whitelock, Derek Paul

    1994-01-01

    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 ...

  10. deep highresolution optical log dust, ash, and stratigraphy South Pole glacial

    E-Print Network [OSTI]

    Woschnagg, Kurt

    deep high­resolution optical log dust, ash, and stratigraphy South Pole glacial Bramall, Bay, Rohde, Price (2005), high­resolution optical dust, stratigraphy South Pole glacial Geophys. Res. Lett

  11. Interaction and Deformation of Viscoelastic Particles. 2. Adhesive Particles

    E-Print Network [OSTI]

    Attard, Phil

    Interaction and Deformation of Viscoelastic Particles. 2. Adhesive Particles Phil Attard Ian Wark, 2001. In Final Form: April 30, 2001 Analyzed is the mutual deformation of adhesive particles the particles' adhesion. An analytic

  12. Observations of heterogeneous reactions between Asian pollution and mineral dust over the Eastern North Pacific during INTEX-B

    E-Print Network [OSTI]

    2009-01-01

    light scattering, due to competition between pollution andAsian pollution and mineral dust Table 8. Changes to lightpollution and mineral dust Table 6. Comparison of light

  13. A GCM investigation of dust aerosol impact on the regional climate of North Africa and South/East Asia

    E-Print Network [OSTI]

    Gu, Y; Xue, Y; de Sales, F; Liou, KN

    2015-01-01

    Chem suggested that whether aero- sols enhance or suppresssemi-arid region. Dust aero- sols also appear in Australiaresults that the dust aero- sol effects on precipitation

  14. Gas sensitive materials for gas detection and methods of making

    DOE Patents [OSTI]

    Trakhtenberg, Leonid Israilevich; Gerasimov, Genrikh Nikolaevich; Gromov, Vladimir Fedorovich; Rozenberg, Valeriya Isaakovna

    2014-07-15

    A gas sensitive material comprising SnO.sub.2 nanocrystals doped with In.sub.2O.sub.3 and an oxide of a platinum group metal, and a method of making the same. The platinum group metal is preferably Pd, but also may include Pt, Ru, Ir, and combinations thereof. The SnO.sub.2 nanocrystals have a specific surface of 7 or greater, preferably about 20 m2/g, and a mean particle size of between about 10 nm and about 100 nm, preferably about 40 nm. A gas detection device made from the gas sensitive material deposited on a substrate, the gas sensitive material configured as a part of a current measuring circuit in communication with a heat source.

  15. Gas sensitive materials for gas detection and method of making

    DOE Patents [OSTI]

    Trakhtenberg, Leonid Israilevich; Gerasimov, Genrikh Nikolaevich; Gromov, Vladimir Fedorovich; Rozenberg, Valeriya Isaakovna

    2012-12-25

    A gas sensitive material comprising SnO2 nanocrystals doped with In2O3 and an oxide of a platinum group metal, and a method of making the same. The platinum group metal is preferably Pd, but also may include Pt, Ru, Ir, and combinations thereof. The SnO2 nanocrystals have a specific surface of 7 or greater, preferably about 20 m2/g, and a mean particle size of between about 10 nm and about 100 nm, preferably about 40 nm. A gas detection device made from the gas sensitive material deposited on a substrate, the gas sensitive material configured as a part of a current measuring circuit in communication with a heat source.

  16. Experimental quiescent drifting dusty plasmas and temporal dust acoustic wave growth

    E-Print Network [OSTI]

    Merlino, Robert L.

    Experimental quiescent drifting dusty plasmas and temporal dust acoustic wave growth J. R. Heinrich quiescent drifting dusty plasmas and temporal dust acoustic wave growth J. R. Heinrich, S.-H. Kim, J. K report on dust acoustic wave growth rate measurements taken in a dc (anode glow) discharge plasma device

  17. Nonlinear Dust Acoustic Waves, Shocks and Stationary Structures in a DC Glow Discharge Dusty Plasma

    E-Print Network [OSTI]

    Merlino, Robert L.

    Nonlinear Dust Acoustic Waves, Shocks and Stationary Structures in a DC Glow Discharge Dusty Plasma drifting dusty plasmas and temporal dust acoustic wave growth Phys. Plasmas 18, 113706 (2011) Modulational;Nonlinear Dust Acoustic Waves, Shocks and Stationary Structures in a DC Glow Discharge Dusty Plasma Robert L

  18. Mineral dust emission from the Bodele Depression, northern Chad, during BoDEx 2005

    E-Print Network [OSTI]

    Washington, Richard

    distribution of this diatomite dust estimated from sun photometer data, using a modified Aeronet retrieval loadings results in a reduction in surface daytime maximum temperature of around 7°C in the Bode´le´ region-blown terrestrial mineral dust. The distribution, properties of mineral dust and its climate impact are poorly

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

    E-Print Network [OSTI]

    Daniel, Rosenfeld

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

  20. Saharan mineral dust transport into the Caribbean: Observed atmospheric controls and trends

    E-Print Network [OSTI]

    Hameed, Sultan

    Saharan mineral dust transport into the Caribbean: Observed atmospheric controls and trends O. M December 2007; published 15 April 2008. [1] Each summer large amounts of mineral dust from the Sahara in this region. In this paper we analyze summer season interannual variability of North African mineral dust over

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

    E-Print Network [OSTI]

    Lu, Chenyang

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

  2. Proxies and Measurement Techniques for Mineral Dust in

    E-Print Network [OSTI]

    Fischer, Hubertus

    concentrations, which are typically a factor 100, differ between the methods by up to a factor of 2Proxies and Measurement Techniques for Mineral Dust in Antarctic Ice Cores U R S R U T H , * , C, Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Denmark, Department

  3. Global observations and spectral characteristics of desert dust and

    E-Print Network [OSTI]

    Graaf, Martin de

    characteristics of desert dust and biomass burning scenes · Conclusions and Outlook #12;where Rayleigh R340 Doubling-Adding KNMI Radiative Transfer Model Solar zenith angle = 30° Viewing zenith angle = 0° Surface Model Solar zenith angle = 30° Viewing zenith angle = 0° Surface albedo = 5% Absorbing aerosols

  4. Global observations of desert dust and biomass burning aerosols

    E-Print Network [OSTI]

    Graaf, Martin de

    and desert dust observations from GOME and SCIAMACHY · Conclusions and Outlook #12; · Absorbing Aerosol Transfer Model Solar zenith angle = 30° Viewing zenith angle = 0° Surface albedo = 5% #12;Reflectance at TOA with absorbing aerosols Doubling-Adding KNMI Radiative Transfer Model Solar zenith angle = 30

  5. WEATHER MODIFICATION BY CARBON DUST ABSORPTION OF SOLAR ENERGY

    E-Print Network [OSTI]

    Gray, William

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

  6. Friday, March 27, 2009 MARS: DUNES, DUST, AND WIND

    E-Print Network [OSTI]

    Rathbun, Julie A.

    Friday, March 27, 2009 MARS: DUNES, DUST, AND WIND 8:30 a.m. Waterway Ballroom 1 Chairs: Lori Fenton Steve Metzger 8:30 a.m. Chojnacki M. * Moersch J. E. Valles Marineris Dune Fields: Thermophysical Properties, Morphology, and Provenance [#2486] We examined 25 dune fields in Valles Marineris to identify

  7. ORIGINAL PAPER Relationship between African dust carried in the Atlantic

    E-Print Network [OSTI]

    Prospero, Joseph M.

    the daily concentrations of dust measured in on-shore Trade Winds at Barbados and pediatric asthma Scott Polyclinic, Queen Elizabeth Hospital, Barbados, West Indies R. Naidu :H. Thani Faculty of Medical Sciences, The University of the West Indies, Cave Hill Campus, Barbados, West Indies R. Naidu :H. Thani

  8. The metal and dust yields of the first massive stars

    E-Print Network [OSTI]

    Marassi, S; Limongi, M; Chieffi, A; Bocchio, M; Bianchi, S

    2015-01-01

    We quantify the role of Population (Pop) III core-collapse supernovae (SNe) as the first cosmic dust polluters. Starting from a homogeneous set of stellar progenitors with masses in the range [13 - 80] Msun, we find that the mass and composition of newly formed dust depend on the mixing efficiency of the ejecta and the degree of fallback experienced during the explosion. For standard Pop III SNe, whose explosions are calibrated to reproduce the average elemental abundances of Galactic halo stars with [Fe/H] < -2.5, between 0.18 and 3.1 Msun (0.39 - 1.76 Msun) of dust can form in uniformly mixed (unmixed) ejecta, and the dominant grain species are silicates. We also investigate dust formation in the ejecta of faint Pop III SN, where the ejecta experience a strong fallback. By examining a set of models, tailored to minimize the scatter with the abundances of carbon-enhanced Galactic halo stars with [Fe/H ] < -4, we find that amorphous carbon is the only grain species that forms, with masses in the range 2...

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

    E-Print Network [OSTI]

    Noboa, Homero L.

    1993-01-01

    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...

  10. Dust Aerosol Important for Snowball Earth Deglaciation DORIAN S. ABBOT

    E-Print Network [OSTI]

    Halevy, Itay

    December 2009) ABSTRACT Most previous global climate model simulations could only produce the termination of Snowball Earth episodes at CO2 partial pressures of several tenths of a bar, which is roughly an order in the partial pressure of CO2 from 1024 to 1021 bar. Therefore the conclusion is reached that including dust

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

    E-Print Network [OSTI]

    Hamilton, Douglas P.

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

  12. Nuclear & Particle Physics, Astrophysics, Cosmology

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

    Nuclear & Particle Physics science-innovationassetsimagesicon-science.jpg Nuclear & Particle Physics, Astrophysics, Cosmology National security depends on science and...

  13. Stable levitation and dynamics of ice particles at low pressures

    E-Print Network [OSTI]

    Nicholas Kowalski; Bernard Xie; Colin V. Parker; Cheng Chin

    2015-04-13

    We demonstrate stable levitation and trapping of ice particles of 30~200 micon at low background gas pressures in the presence of a temperature gradient. The thermophoretic force levitates the particles, which have long lifetimes of over an hour. The equilibrium position depends on the background pressure and temperature gradient, which is consistent with theoretical expectations. Furthermore, we investigate interesting launching and merging dynamics of the levitated particles, as well as the development of instability at high background pressures. Our system provides a robust platform to investigate the aggregation of floating ice particles in air, and potentially chemical and biological processes in a microgravity environment.

  14. Dynamical Simulation of Fluidized Beds --- Hydrodynamically Interacting Granular Particles

    E-Print Network [OSTI]

    Kengo Ichiki; Hisao Hayakawa

    1995-03-01

    A numerical simulation of a gas-fluidized bed is performed without introduction of any empirical parameters. Realistic bubbles and slugs are observed in our simulation. It is found that the convective motion of particles is important for the bubbling phase and there is no convection in the slugging phase. From the simulation results, non-Gaussian distributions are found in the particle velocities and the relation between the deviation from Gaussian and the local density of particles is suggested. It is also shown that the power spectra of particle velocities obey power laws. A brief explanation on the relationship between the simulation results and the Kolmogorov scaling argument is discussed.

  15. Method and apparatus for cutting, abrading, and drilling with sublimable particles and vaporous liquids

    DOE Patents [OSTI]

    Bingham, D.N.; Swainston, R.C.; Palmer, G.L.

    1998-03-31

    A gas delivery system provides a first gas which is in a liquid state under extreme pressure and in a gaseous state under intermediate pressure. A particle delivery system provides a slurry comprising the first gas in a liquid state and a second gas in a solid state. The second gas is selected so that it will solidify at a temperature at or above the temperature of the first gas in a liquid state. A nozzle assembly connected to the gas delivery system and to the particle delivery system produces a stream having a high velocity central jet comprising the slurry, a liquid sheath surrounding the central jet comprising the first gas in a liquid state and an outer jacket surrounding the liquid sheath comprising the first gas in a gas state. 19 figs.

  16. Method and apparatus for cutting, abrading, and drilling with sublimable particles and vaporous liquids

    DOE Patents [OSTI]

    Bingham, Dennis N. (Idaho Falls, ID); Swainston, Richard C. (Shelley, ID); Palmer, Gary L. (Shelley, ID)

    1998-01-01

    A gas delivery system provides a first gas which is in a liquid state under extreme pressure and in a gaseous state under intermediate pressure. A particle delivery system provides a slurry comprising the first gas in a liquid state and a second gas in a solid state. The second gas is selected so that it will solidify at a temperature at or above the temperature of the first gas in a liquid state. A nozzle assembly connected to the gas delivery system and to the particle delivery system produces a stream having a high velocity central jet comprising the slurry, a liquid sheath surrounding the central jet comprising the first gas in a liquid state and an outer jacket surrounding the liquid sheath comprising the first gas in a gas state.

  17. Dual porosity gas evolving electrode

    DOE Patents [OSTI]

    Townsend, C.W.

    1994-11-15

    A dual porosity electrode is described for use in thermoelectrochemical systems where simultaneous transport of gas and liquid into and/or out of the electrode is required. The electrode includes catalytic electrode particles having diameters ranging from about 25 to 100 angstroms. The catalytic electrode particles are anchored to a support network in clusters which have internal pores ranging in size from 25 to 100 angstroms. The pores between the clusters range in size from between about 1 to 20 microns. A method for making the dual porosity electrodes is also disclosed.

  18. Characterization of Fundamental Particles

    E-Print Network [OSTI]

    Ben J Baten

    2009-05-25

    This report provides an alternative to the Standard Model of particle physics. The model described here is based on results from Quantum Field Mechanics, according to which all fundamental particles and interactions originate from the interaction of two pre-space/pre-time protofields. In contrast with the Standard Model, (virtual) interaction-particles are absent in the description of any of the four fundamental interactions. Electrons perform a single quantum beat process while mesons and baryons have, respectively, two and three bound quantum beat processes. Quantum Field Mechanics suggests that the charge of an electron and positron can be identified with the two possible phases of a quantum beat process as observed in the electromagnetic protofield. This report assumes that short-range binding interaction between quantum beat processes has a masking effect on the externally observable charge of hadrons. Using this assumption, the internal structure of particles is derived from their known particle charges and relative masses. The particle structures are used to obtain the so-called charge-quantum phase law. The fractional charge of quantum beat processes inside a particle is deduced by rewriting the charge-quantum phase law in terms of a linear combination of charge contributions of individual constituent quantum beat processes. Strangeness and isospin are mathematically defined in terms of the quantum beat phases of sets of particles of the same type. Application of conservation laws to particle processes leads to relations between quantum phase, strangeness and isospin.

  19. Cooling of Dense Gas by H2O Line Emission and an Assessment of its Effects in Chondrule-Forming Shocks

    E-Print Network [OSTI]

    M. A. Morris; S. J. Desch; F. J. Ciesla

    2008-09-29

    We consider gas at densities appropriate to protoplanetary disks and calculate its ability to cool due to line radiation emitted by H2O molecules within the gas. Our work follows that of Neufeld & Kaufman (1993; ApJ, 418, 263), expanding on their work in several key aspects, including use of a much expanded line database, an improved escape probability formulism, and the inclusion of dust grains, which can absorb line photons. Although the escape probabilities formally depend on a complicated combination of optical depth in the lines and in the dust grains, we show that the cooling rate including dust is well approximated by the dust-free cooling rate multiplied by a simple function of the dust optical depth. We apply the resultant cooling rate of a dust-gas mixture to the case of a solar nebula shock pertinent to the formation of chondrules, millimeter-sized melt droplets found in meteorites. Our aim is to assess whether line cooling can be neglected in chondrule-forming shocks or if it must be included. We find that for typical parameters, H2O line cooling shuts off a few minutes past the shock front; line photons that might otherwise escape the shocked region and cool the gas will be absorbed by dust grains. During the first minute or so past the shock, however, line photons will cool the gas at rates ~ 10,000 K/hr, dropping the temperature of the gas (and most likely the chondrules within the gas) by several hundred K. Inclusion of H2O line cooling therefore must be included in models of chondrule formation by nebular shocks.

  20. 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

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

    SciTech Connect (OSTI)

    Carter, C M

    2012-04-25

    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.

  2. Gas hydrates

    SciTech Connect (OSTI)

    Not Available

    1985-04-01

    There is a definite need for the US government to provide leadership for research in gas hydrates and to coordinate its activities with academia, industry, private groups, federal agencies, and their foreign counterparts. In response to this need, the DOE Morgantown Energy Technology Center implemented a gas hydrates R and D program. Understanding the resource will be achieved through: assessment of current technology; characterization of gas hydrate geology and reservoir engineering; and development of diagnostic tools and methods. Research to date has focused on geology. As work progressed, areas where gas hydrates are likely to occur were identified, and specific high potential areas were targeted for future detailed investigation. Initial research activities involved the development of the Geologic Analysis System (GAS); which will provide, through approximately 30 software packages, the capability to manipulate and correlate several types of geologic and petroleum data into maps, graphics, and reports. Preliminary mapping of hydrate prospects for the Alaskan North Slope is underway. Geological research includes physical system characterization which focuses on creating synthetic methane hydrates and developing synthetic hydrate cores using tetrahydrofuran, consolidated rock cores, frost base mixtures, water/ice base mixtures, and water base mixtures. Laboratory work produced measurements of the sonic velocity and electrical resistivity of these synthetic hydrates. During 1983, a sample from a natural hydrate core recovered from the Pacific coast of Guatemala was tested for these properties by METC. More recently, a natural hydrate sample from the Gulf of Mexico was also acquired and testing of this sample is currently underway. In addition to the development of GAS, modeling and systems analysis work focused on the development of conceptual gas hydrate production models. 16 figs., 6 tabs.

  3. Dust Acoustic Solitons in the Dusty Plasma of the Earth's Ionosphere

    SciTech Connect (OSTI)

    Kopnin, S.I.; Kosarev, I.N.; Popel, S.I.; Yu, M.Y.

    2005-03-15

    Stratified structures that are observed at heights of 80-95 km in the lower part of the Earth's ionosphere are known as noctilucent clouds and polar mesosphere summer echoes. These structures are thought to be associated with the presence of vast amounts of charged dust or aerosols. The layers in the lower ionosphere where there are substantial amounts of dust are called the dusty ionosphere. The dust grains can carry a positive or a negative charge, depending on their constituent materials. As a rule, the grains are ice crystals, which may contain metallic inclusions. A grain with a sufficiently large metallic content can acquire a positive charge. Crystals of pure ice are charged negatively. The distribution of the dust grains over their charges has a profound impact on the ionizational and other properties of dust structures in the dusty ionosphere. In the present paper, a study is made of the effect of the sign of the dust charge on the properties of dust acoustic solitons propagating in the dusty ionosphere. It is shown that, when the dust charge is positive, dust acoustic solitons correspond to a hill in the electron density and a well in the ion density. When the dust is charged negatively, the situation is opposite. These differences in the properties of dust acoustic solitons can be used to diagnose the plasmas of noctilucent clouds and polar mesosphere summer echoes.

  4. How important are metal-poor AGB stars as cosmic dust producers?

    E-Print Network [OSTI]

    Mattsson, Lars; Andersen, Anja C

    2015-01-01

    The efficiency of dust formation in oxygen-rich AGB stars should (in theory) be metallicity dependent since they are not producing their own raw material for dust production. Metal-poor carbon stars may not be very efficient dust producers either, because of more radiative heating of the grains forming in their atmospheres. We have just confirmed that inefficient dust and wind formation in simulations of metal-poor carbon stars is a real physical effect, albeit within the limitations of our simulations. Taken at face value, this implies that the amount of dust supplied by low-metallicity AGB stars to the build up of the cosmic dust component is clearly limited. Consequently, one may also ask how large a contribution AGB stars can make in general, when compared to recent observations of cosmic dust, which are suggesting major contributions from other sources?

  5. Infrared Spectroscopy of U Equulei's Warm Circumstellar Gas

    E-Print Network [OSTI]

    T. R. Geballe; C. Barnbaum; Keith S. Noll; M. Morris

    2005-03-18

    Medium and high resolution spectroscopy of U Equulei from 1 to 4 microns during 1997-2003 has revealed information about its unusual circumstellar envelope, observed previously at optical and radio wavelengths. Strong absorption bands of H2O and of CO dominate the 1-4um spectrum. The gas has a mean temperature of 600 K and 12C/13C =< 10. The CO 2-0 line profiles and velocities imply no net ejection or infall and indicate either rapid radial gas motions being seen along a narrow continuum beam, or absorption by orbiting gas that is nearly coincident with a highly extended continuum source. The gas could be located in a disk-like structure. The observed high column densities of warm CO and H2 normally would be associated with sufficient dust to completely obscure the star at optical wavelengths. The observations thus indicate either a highly abnormal gas-to-dust ratio, consistent with the earlier optical observation of abundant refractory metal oxides in the circumstellar gas, or peculiar geometry and/or illumination.

  6. RESEARCH IN PARTICLE PHYSICS

    SciTech Connect (OSTI)

    Kearns, Edward

    2013-07-12

    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.

  7. Pileup per particle identification

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bertolini, Daniele; Harris, Philip; Low, Matthew; Tran, Nhan

    2014-10-09

    We propose a new method for pileup mitigation by implementing “pileup per particle identification” (PUPPI). For each particle we first define a local shape ? 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 ? 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 tomore »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 pT and jet mass. We also find an improvement on non-jet quantities like missing transverse energy.« less

  8. REVIEW OF PARTICLE PHYSICS

    E-Print Network [OSTI]

    Beringer, Juerg

    2013-01-01

    APS Careers: gateway for physicists, students, and physicsAPS/DPF/DPB Summer Study on the Future of Particle Physics (APS Acta Physica Slovaca ARNPS Annual Review of Nuclear and Particle Science ARNS Annual Review of Nuclear Science ASP Astroparticle Physics

  9. Review of Particle Physics

    E-Print Network [OSTI]

    Nakamura, Kenzo

    2010-01-01

    careersvc/ • APS Careers in Physics: The American PhysicalAPS/DPF/DPB Summer Study on the Future of Particle Physics (APS Acta Physica Slovaca ARNPS Annual Review of Nuclear and Particle Science ARNS Annual Review of Nuclear Science ASP Astroparticle Physics

  10. Wave Particles Cem Yuksel

    E-Print Network [OSTI]

    Keyser, John

    Wave Particles Cem Yuksel Computer Science Texas A&M University Donald H. House Visualization captured from our real-time simulation system (approximately 100,000 wave particles) Abstract We present a new method for the real-time simulation of fluid sur- face waves and their interactions with floating

  11. Pileup per particle identification

    SciTech Connect (OSTI)

    Bertolini, Daniele; Harris, Philip; Low, Matthew; Tran, Nhan

    2014-10-09

    We propose a new method for pileup mitigation by implementing “pileup per particle identification” (PUPPI). For each particle we first define a local shape ? 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 ? 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 pT and jet mass. We also find an improvement on non-jet quantities like missing transverse energy.

  12. Alternating current long range alpha particle detector

    DOE Patents [OSTI]

    MacArthur, D.W.; McAtee, J.L.

    1993-02-16

    An alpha particle detector, utilizing alternating currents, which is capable of detecting alpha particles from distinct sources. The use of alternating currents allows use of simpler ac circuits which, in turn, are not susceptible to dc error components. It also allows the benefit of gas gain, if desired. In the invention, a voltage source creates an electric field between two conductive grids, and between the grids and a conductive enclosure. Air containing air ions created by collision with alpha particles is drawn into the enclosure and detected. In some embodiments, the air flow into the enclosure is interrupted, creating an alternating flow of ions. In another embodiment, a modulated voltage is applied to the grid, also modulating the detection of ions.

  13. Braking the Gas in the beta Pictoris Disk

    E-Print Network [OSTI]

    Fern'andez, R; Wu, Y; Brandeker, Alexis; Fern\\'andez, Rodrigo

    2006-01-01

    (Abridged) The main sequence star beta Pictoris hosts the best studied circumstellar disk to date. Nonetheless, a long-standing puzzle has been around since the detection of metallic gas in the disk: radiation pressure from the star should blow the gas away, yet the observed motion is consistent with Keplerian rotation. In this work we search for braking mechanisms that can resolve this discrepancy. We find that all species affected by radiation force are heavily ionized and dynamically coupled into a single fluid by Coulomb collisions, reducing the radiation force on species feeling the strongest acceleration. For a gas of solar composition, the resulting total radiation force still exceeds gravity, while a gas of enhanced carbon abundance could be self-braking. We also explore two other braking agents: collisions with dust grains and neutral gas. Grains surrounding beta Pic are photoelectrically charged to a positive electrostatic potential. If a significant fraction of the grains are carbonaceous (10% in t...

  14. 146 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 27, NO. 1, FEBRUARY 1999 Video Imaging of Dust Acoustic Waves

    E-Print Network [OSTI]

    Merlino, Robert L.

    Acoustic Waves C. Thompson, A. Barkan, R. L. Merlino, and N. D'Angelo Fig. 1. Single video frame image of a dust acoustic wave. The bright vertical bands correspond to the wave crests (dust compressions "dust waves." A sample image of a dust acoustic wave is presented. Index Terms--Image analysis, plasma

  15. A survey of spatially distributed exterior dust lead loadings in New York City

    SciTech Connect (OSTI)

    Caravanos, Jack; Weiss, Arlene L.; Blaise, Marc J.; Jaeger, Rudolph J. . E-mail: jaegerr@envmed.com

    2006-02-15

    This work documents ambient lead dust deposition values (lead loading) for the boroughs of New York City in 2003-2004. Currently, no regulatory standards exist for exterior concentrations of lead in settled dust. This is in contrast to the clearance and risk assessment standards that exist for interior residential dust. The reported potential for neurobehavioral toxicity and adverse cognitive development in children due to lead exposure prompts public health concerns about undocumented lead sources. Such sources may include settled dust of outdoor origin. Dust sampling throughout the five boroughs of NYC was done from the top horizontal portion of pedestrian traffic control signals (PTCS) at selected street intersections along main thoroughfares. The data (n=214 samples) show that lead in dust varies within each borough with Brooklyn having the highest median concentration (730{mu}g/ft{sup 2}), followed in descending order by Staten Island (452{mu}g/ft{sup 2}), the Bronx (382{mu}g/ft{sup 2}), Queens (198{mu}g/ft{sup 2}) and finally, Manhattan (175{mu}g/ft{sup 2}). When compared to the HUD/EPA indoor lead in dust standard of 40{mu}g/ft{sup 2}, our data show that this value is exceeded in 86% of the samples taken. An effort was made to determine the source of the lead in the dust atop of the PTCS. The lead in the dust and the yellow signage paint (which contains lead) were compared using isotopic ratio analysis. Results showed that the lead-based paint chip samples from intact signage did not isotopically match the dust wipe samples taken from the same surface. We know that exterior dust containing lead contributes to interior dust lead loading. Therefore, settled leaded dust in the outdoor environment poses a risk for lead exposure to children living in urban areas, namely, areas with elevated childhood blood lead levels and background lead dust levels from a variety of unidentified sources.

  16. A parametric modeling approach to measuring the gas masses of circumstellar disks

    SciTech Connect (OSTI)

    Williams, Jonathan P.; Best, William M. J. E-mail: wbest@ifa.hawaii.edu

    2014-06-10

    The disks that surround young stars are mostly composed of molecular gas, which is harder to detect and interpret than the accompanying dust. Disk mass measurements have therefore relied on large and uncertain extrapolations from the dust to the gas. We have developed a grid of models to study the dependencies of isotopologue CO line strengths on disk structure and temperature parameters and find that a combination of {sup 13}CO and C{sup 18}O observations provides a robust measure of the gas mass. We apply this technique to Submillimeter Array observations of nine circumstellar disks and published measurements of six well studied disks. We find evidence for selective photodissociation of C{sup 18}O and determine masses to within a factor of about three. The inferred masses for the nine disks in our survey range from 0.7 to 6 M {sub Jup}, and all are well below the extrapolation from the interstellar medium gas-to-dust ratio of 100. This is consistent with the low masses of planets found around such stars, and may be due to accretion or photoevaporation of a dust-poor upper atmosphere. However, the masses may be underestimated if there are more efficient CO depletion pathways than those known in molecular clouds and cold cores.

  17. Gas Drill 

    E-Print Network [OSTI]

    Unknown

    2011-09-05

    .C. Wang, B.T. Lovell, Program, Summary Report TE4258-5-84, J. McCrank, "Topping of a Combined Gas DOE/ET/11292, Oct. 1984. and Steam Turbine Powerplant using a TAM Combustor," Thermo Electron [4J Final Report: "Thermionic Energy Report No. 4258... for each Btu fired in the burners has been cal culated with the process gas temperature as a variable. It was shown [2 ] that the maximum thermionic power produced is 18 kW per million Btu fired per hour. All com bustors are similar but progressively...

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

    SciTech Connect (OSTI)

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

    2013-09-01

    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.

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

    E-Print Network [OSTI]

    Herber, Douglas John

    1988-01-01

    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...

  20. Sub-micron particle sampler apparatus and method for sampling sub-micron particles

    DOE Patents [OSTI]

    Gay, D.D.; McMillan, W.G.

    1984-04-12

    Apparatus and method steps for collecting sub-micron sized particles include a collection chamber and cryogenic cooling. The cooling is accomplished by coil tubing carrying nitrogen in liquid form, with the liquid nitrogen changing to the gas phase before exiting from the collection chamber in the tubing. Standard filters are used to filter out particles of diameter greater than or equal to 0.3 microns; however, the present invention is used to trap particles of less than 0.3 micron in diameter. A blower draws air to said collection chamber through a filter which filters particles with diameters greater than or equal to 0.3 micron. The air is then cryogenically cooled so that moisture and sub-micron sized particles in the air condense into ice on the coil. The coil is then heated so that the ice melts, and the liquid is then drawn off and passed through a Buchner funnel where the liquid is passed through a Nuclepore membrane. A vacuum draws the liquid through the Nuclepore membrane, with the Nuclepore membrane trapping sub-micron sized particles therein. The Nuclepore membrane is then covered on its top and bottom surfaces with sheets of Mylar and the assembly is then crushed into a pellet. This effectively traps the sub-micron sized particles for later analysis. 6 figures.

  1. Experimental evidence of water formation on interstellar dust grains

    E-Print Network [OSTI]

    Dulieu, F; Fillion, J-H; Matar, E; Momeni, A; Pirronello, V; Lemaire, J L

    2009-01-01

    The synthesis of water is one necessary step in the origin and development of life. It is believed that pristine water is formed and grows on the surface of icy dust grains in dark interstellar clouds. Until now, there has been no experimental evidence whether this scenario is feasible or not. We present here the first experimental evidence of water synthesis under interstellar conditions. After D and O deposition on a water ice substrate (HO) held at 10 K, we observe production of HDO and DO. The water substrate itself has an active role in water formation, which appears to be more complicated than previously thought. Amorphous water ice layers are the matrices where complex organic prebiotic species may be synthesized. This experiment opens up the field of a little explored complex chemistry that could occur on interstellar dust grains, believed to be the site of key processes leading to the molecular diversity and complexity observed in our universe.

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

    SciTech Connect (OSTI)

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

    2013-10-01

    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.

  3. Gas sensor

    DOE Patents [OSTI]

    Schmid, Andreas K.; Mascaraque, Arantzazu; Santos, Benito; de la Figuera, Juan

    2014-09-09

    A gas sensor is described which incorporates a sensor stack comprising a first film layer of a ferromagnetic material, a spacer layer, and a second film layer of the ferromagnetic material. The first film layer is fabricated so that it exhibits a dependence of its magnetic anisotropy direction on the presence of a gas, That is, the orientation of the easy axis of magnetization will flip from out-of-plane to in-plane when the gas to be detected is present in sufficient concentration. By monitoring the change in resistance of the sensor stack when the orientation of the first layer's magnetization changes, and correlating that change with temperature one can determine both the identity and relative concentration of the detected gas. In one embodiment the stack sensor comprises a top ferromagnetic layer two mono layers thick of cobalt deposited upon a spacer layer of ruthenium, which in turn has a second layer of cobalt disposed on its other side, this second cobalt layer in contact with a programmable heater chip.

  4. Naked singularities in higher dimensional inhomogeneous dust collapse

    E-Print Network [OSTI]

    S G Ghosh; A Beesham

    2001-06-27

    We investigate the occurrence and nature of a naked singularity in the gravitational collapse of an inhomogeneous dust cloud described by a non self-similar higher dimensional Tolman spacetime. The necessary condition for the formation of a naked singularity or a black hole is obtained. The naked singularities are found to be gravitationally strong in the sense of Tipler and provide another example that violates the cosmic censorship conjecture.

  5. Canadian House Dust Study: Lead Bioaccessibility and Speciation

    SciTech Connect (OSTI)

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

    2011-12-31

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

  6. Chemical Dust Treatment of Cottonseed for Planting Purposes. 

    E-Print Network [OSTI]

    Smith, H. P. (Harris Pearson)

    1936-01-01

    -. lHEMICAL DUST TREATMENT OF COTTONSEED FOR PLANTING PURPOSES H. P. Smith, Chief, Division of Agricultural Engineering D. L. Jones, Superintendent, Substation No. 8, Lubl~ock D. T. Killough, Agronomist, Division of Agronomy H. C. Mc... Reports 3 6 to 41, inclusive. 10. Killough, D. T., "Cottonseed Treatment Proves Profitable." Progres- sive Farmer, Vol. 4 8, No. 3, March 19 3 3. 11. Lehman, S. G., "Studies on Treatment of Cottonseed." North Caro- lina Agricultural Experiment Station...

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

    E-Print Network [OSTI]

    Muhammad Sharif; Hafiza Rizwana Kausar

    2011-02-21

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

  8. Charged particle accelerator grating

    DOE Patents [OSTI]

    Palmer, Robert B. (Shoreham, NY)

    1986-01-01

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams into the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  9. The Evolution of Inner Disk Gas in Transition Disks

    E-Print Network [OSTI]

    Hoadley, Keri; Alexander, Richard D; McJunkin, Matthew; Schneider, Christian

    2015-01-01

    Investigating the molecular gas in the inner regions of protoplanetary disks provides insight into how the molecular disk environment changes during the transition from primordial to debris disk systems. We conduct a small survey of molecular hydrogen (H$_2$) fluorescent emission, using 14 well-studied Classical T Tauri stars at two distinct dust disk evolutionary stages, to explore how the structure of the inner molecular disk changes as the optically thick warm dust dissipates. We simulate the observed HI-Lyman $\\alpha$-pumped H$_2$ disk fluorescence by creating a 2D radiative transfer model that describes the radial distributions of H$_{2}$ emission in the disk atmosphere and compare these to observations from the Hubble Space Telescope. We find the radial distributions that best describe the observed H$_2$ FUV emission arising in primordial disk targets (full dust disk) are demonstrably different than those of transition disks (little-to-no warm dust observed). For each best-fit model, we estimate inner a...

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

    E-Print Network [OSTI]

    Ana Campos; Tom Shanks

    1995-11-23

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

  11. Spherical Domain Wall Collapse in a Dust Universe

    E-Print Network [OSTI]

    Norihiro Tanahashi; Chul-Moon Yoo

    2015-05-13

    To clarify observational consequence of bubble nucleations in inflationary era, we analyse dynamics of a spherical domain wall in an expanding universe. We consider a spherical shell of the domain wall with tension $\\sigma$ collapsing in a spherically-symmetric dust universe, which is initially separated into the open Friedmann-Lema\\^itre-Robertson-Walker universe inside the shell and the Einstein-de Sitter universe outside. The domain wall shell collapses due to the tension, and sweeps the dust fluid. The universe after the collapse becomes inhomogeneous and is described by the Lema\\^itre-Tolman-Bondi model. We construct solutions describing this inhomogeneous universe by solving dynamical equations obtained from Israel's junction conditions applied to this system. We find that a black hole forms after the domain wall collapse for any initial condition, and that the black hole mass at the moment of its formation is universally given by $M_{\\rm BH}\\simeq 17 \\sigma/H_{\\rm hc}$, where $H_{\\rm hc}$ is the Hubble parameter at the time when the shell radius becomes equal to the Hubble radius. We also find that the dust fluid is distributed as $\\rho\\propto R^{3/2}$ near the central region after the collapse, where $R$ is the area radius. These features would provide observable signatures of a spherical domain wall generated in the early universe.

  12. Coke battery with 51-m{sup 3} furnace chambers and lateral supply of mixed gas

    SciTech Connect (OSTI)

    V.I. Rudyka; N.Y. Chebotarev; O.N. Surenskii; V.V. Derevich [Giprokoks, the State Institute for the Design of Coke-Industry Enterprises, Kharkov (Ukraine)

    2009-07-15

    The basic approaches employed in the construction of coke battery 11A at OAO Magnitogorskii Metallurgicheskii Kombinat are outlined. This battery includes 51.0-m{sup 3} furnaces and a dust-free coke-supply system designed by Giprokoks with lateral gas supply; it is heated exclusively by low-calorific mixed gas consisting of blast-furnace gas with added coke-oven gas. The 82 furnaces in the coke battery are divided into two blocks of 41. The gross coke output of the battery (6% moisture content) is 1140000 t/yr.

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

    SciTech Connect (OSTI)

    Dixon-Hardy, D.W.; Beyhan, S.; Ediz, I.G.; Erarslan, K.

    2008-10-15

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

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

    SciTech Connect (OSTI)

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

    2014-12-01

    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.

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

    ScienceCinema (OSTI)

    None

    2011-04-25

    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.

  16. Accelerating Particles with Plasma

    SciTech Connect (OSTI)

    Litos, Michael; Hogan, Mark

    2014-11-05

    Researchers at SLAC explain how they use plasma wakefields to accelerate bunches of electrons to very high energies over only a short distance. Their experiments offer a possible path for the future of particle accelerators.

  17. Particle Physics Masterclass

    ScienceCinema (OSTI)

    Helio Takai

    2010-01-08

    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,

  18. Safe biodegradable fluorescent particles

    DOE Patents [OSTI]

    Martin, Sue I. (Berkeley, CA); Fergenson, David P. (Alamo, CA); Srivastava, Abneesh (Santa Clara, CA); Bogan, Michael J. (Dublin, CA); Riot, Vincent J. (Oakland, CA); Frank, Matthias (Oakland, CA)

    2010-08-24

    A human-safe fluorescence particle that can be used for fluorescence detection instruments or act as a safe simulant for mimicking the fluorescence properties of microorganisms. The particle comprises a non-biological carrier and natural fluorophores encapsulated in the non-biological carrier. By doping biodegradable-polymer drug delivery microspheres with natural or synthetic fluorophores, the desired fluorescence can be attained or biological organisms can be simulated without the associated risks and logistical difficulties of live microorganisms.

  19. ELEMENTARY PARTICLE INTERACTIONS

    SciTech Connect (OSTI)

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

    2013-07-30

    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.

  20. Particle deposition in ventilation ducts

    E-Print Network [OSTI]

    Sippola, Mark R.

    2002-01-01

    were observed to lead to resuspension of particles in thethe nozzles may lead to resuspension of deposited particles.resuspension, the decreased response to turbulent velocity fluctuations of the very large particles should lead