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1

Bipolar charging of dust particles under ultraviolet radiation  

SciTech Connect

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

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

2011-05-15T23:59:59.000Z

2

Stochastic fluctuations of dust particle charge in RF discharges  

Science Conference Proceedings (OSTI)

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

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

2012-05-15T23:59:59.000Z

3

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

SciTech Connect

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

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

2013-03-15T23:59:59.000Z

4

Particle creation in (2+1) circular dust collapse  

E-Print Network (OSTI)

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

Sashideep Gutti; T. P. Singh

2007-01-01T23:59:59.000Z

5

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

SciTech Connect

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

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

2012-09-15T23:59:59.000Z

6

Optical Investigations of Dust Particles Distribution in RF and DC Discharges  

Science Conference Proceedings (OSTI)

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

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

2008-09-07T23:59:59.000Z

7

Ice Nuclei in Marine Air: Biogenic Particles or Dust?  

Science Conference Proceedings (OSTI)

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

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

2013-01-11T23:59:59.000Z

8

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

SciTech Connect

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

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

2011-11-15T23:59:59.000Z

9

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

SciTech Connect

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

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

2005-10-31T23:59:59.000Z

10

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

SciTech Connect

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

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

2011-03-30T23:59:59.000Z

11

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

E-Print Network (OSTI)

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

Princeton Plasma Physics Laboratory

12

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

SciTech Connect

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

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

2009-11-01T23:59:59.000Z

13

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

Science Conference Proceedings (OSTI)

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

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

2012-10-01T23:59:59.000Z

14

Fish breathing  

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

Fish breathing Name: Bob W Whitbeck Age: NA Location: NA Country: NA Date: NA Question: What factors make it harder for fish to breathe? Replies: Fish "breathe" with gills and...

15

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

E-Print Network (OSTI)

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

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

2013-06-11T23:59:59.000Z

16

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

SciTech Connect

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

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

2013-03-15T23:59:59.000Z

17

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

E-Print Network (OSTI)

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

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

2013-01-01T23:59:59.000Z

18

Collision probabilities of migrating small bodies and dust particles with planets  

E-Print Network (OSTI)

Probabilities of collisions of migrating small bodies and dust particles produced by these bodies with planets were studied. Various Jupiter-family comets, Halley-type comets, long-period comets, trans-Neptunian objects, and asteroids were considered. The total probability of collisions of any considered body or particle with all planets did not exceed 0.2. The amount of water delivered from outside of Jupiter's orbit to the Earth during the formation of the giant planets could exceed the amount of water in Earth's oceans. The ratio of the mass of water delivered to a planet by Jupiter-family comets or Halley-type comets to the mass of the planet can be greater for Mars, Venus, and Mercury, than that for Earth.

Ipatov, S I

2009-01-01T23:59:59.000Z

19

Maximizing Ion Current by Space Charge Neutralization using Negative Ions and Dust Particles  

DOE Green Energy (OSTI)

Ion current extracted from an ion source (ion thruster) can be increased above the Child-Langmuir limit if the ion space charge is neutralized. Similarly, the limiting kinetic energy density of the plasma flow in a Hall thruster might be exceeded if additional mechanisms of space charge neutralization are introduced. Space charge neutralization with high-mass negative ions or negatively charged dust particles seems, in principle, promising for the development of a high current or high energy density source of positive light ions. Several space charge neutralization schemes that employ heavy negatively charged particles are considered. It is shown that the proposed neutralization schemes can lead, at best, only to a moderate but nonetheless possibly important increase of the ion current in the ion thruster and the thrust density in the Hall thruster.

A. Smirnov; Y. Raitses; N.J. Fisch

2005-01-25T23:59:59.000Z

20

Fish breathing  

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

Fish breathing Name: lennartz Location: NA Country: NA Date: NA Question: How do fish get their oxygen under water? Replies: Not so differently from the way we get it from air....

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


21

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

E-Print Network (OSTI)

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

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

2013-01-01T23:59:59.000Z

22

Background dust emission following grassland fire: a snapshot across the particle-size spectrum highlights how high-resolution measurements enhance detection  

SciTech Connect

Dust emission rates vary temporally and with particle size. Many studies of dust emission focus on a particular temporal scale and the portion of the particle-size spectrum associated with a single instrument; fewer studies have assessed dust emission across the particle-size spectrum and associated temporal scales using multiple instruments. Particularly lacking are measurements following disturbances such as fire that are high-resolution and focused on finer particles - those with direct implications for human health and potential for long-distance biogeochemical transport - during less windy but more commonly occurring background conditions. We measured dust emissions in unburned and burned semiarid grassland using four different instruments spanning different combinations of temporal resolution and particle-size spectrum: Big Springs Number Eight (BSNE) and Sensit instruments for larger saltating particles, DustTrak instruments for smaller suspended particles, and Total Suspended Particulate (TSP) samplers for measuring the entire range of particle sizes. Unburned and burned sites differed in vegetation cover and aerodynamic roughness, yet surprisingly differences in dust emission rates were only detectable for saltation using BSNE and for smaller aerosols using DustTrak. Our results, surprising in the lack of consistently detected differences, indicate that high-resolution DustTrak measurements offered the greatest promise for detecting differences in background emission rates and that BSNE samplers, which integrate across height, were effective for longer intervals. More generally, our results suggest that interplay between particle size, temporal resolution, and integration across time and height can be complex and may need to be considered more explicitly for effective sampling for background dust emissions.

Whicker, Jeffrey J [Los Alamos National Laboratory; Martin, Luis M [UNIV OF ARIZONA; Field, Jason P [UNIV OF ARIZONA; Villegas, Juan C [UNIV OF ARIZONA; Brehsears, David D [UNIV OF ARIZONA; Law, Darin J [UNIV OF ARIZONA; Urgeghe, Anna M [UNIV OF ARIZONA

2009-01-01T23:59:59.000Z

23

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

E-Print Network (OSTI)

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

Sullivan, Ryan Christopher

2008-01-01T23:59:59.000Z

24

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

SciTech Connect

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

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

2013-01-15T23:59:59.000Z

25

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

E-Print Network (OSTI)

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

Ledenyov, Oleg P

2013-01-01T23:59:59.000Z

26

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

E-Print Network (OSTI)

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

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

2013-02-18T23:59:59.000Z

27

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

E-Print Network (OSTI)

molecular marker of biomass combustion particles (Schauer etproduced from biomass and biofuel combustion typicallyof chlorine include coal combustion, biomass burning, and

Sullivan, Ryan Christopher

2008-01-01T23:59:59.000Z

28

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

SciTech Connect

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

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

2007-01-04T23:59:59.000Z

29

Novel instrument for Dust Astronomy: Dust Telescope  

Science Conference Proceedings (OSTI)

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

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

2011-03-01T23:59:59.000Z

30

Breathing liquid oxygen  

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

question is interesting though because it would be desirable to breath liquid instead of gas under certain conditions. Special liquids are being designed to carry dissolved...

31

TWO INTERSTELLAR DUST CANDIDATES FROM THE STARDUST AEROGEL INTERSTELLAR DUST  

E-Print Network (OSTI)

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

32

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

E-Print Network (OSTI)

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

Oleg P. Ledenyov; Ivan M. Neklyudov

2013-06-14T23:59:59.000Z

33

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

Science Conference Proceedings (OSTI)

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

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

2007-08-28T23:59:59.000Z

34

Dust cluster explosion  

Science Conference Proceedings (OSTI)

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

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

2012-09-15T23:59:59.000Z

35

Thin Air Breathing  

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

Thin Air Breathing Thin Air Breathing Name: Amy Location: N/A Country: N/A Date: N/A Question: Why is it hard to breathe in thin air? What health dangers do mountain climbers face at high altitudes? Replies: Among the obvious dangers of losing ones footing, the oxygen available in the air is considerable less at higher altitudes. If I recall correctly, 21% of the atmosphere at standard temperature and pressure at sea level is composed of oxygen. This is less at higher altitudes. One can lose consciousness and even die in an oxygen deficient environment with changes from oxygen content to lower than 19.5%. This can unfortunate effect can occur within minutes. Dr. Myron The air is not really thin at high altitudes. The problem is that air pressure is lower. As altitude increases, air pressure decreases. In order for your lungs to fill with air, the air pressure in your lungs has to be less than the pressure of the air outside your lungs. Air moves from areas of higher pressure to lower pressure. As your diaphragm (the muscle that separates your chest cavity from your abdominal cavity) moves downward, the size of your chest cavity increases. This decreases the pressure in your chest and air flows in. When the diaphragm is up, it puts pressure on the chest cavity and the pressure in the lungs is greater than outside the lungs. Air flows out. This is an example of Boyle's Law. The movement of the diaphragm is controlled by the brainstem. Anyway-the reason that it is harder for some people to breathe at higher altitudes is that the air pressure differences aren't as great between the inside of the lungs and outside.

36

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

Science Conference Proceedings (OSTI)

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

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

2010-07-16T23:59:59.000Z

37

Breathing zone air sampler  

DOE Patents (OSTI)

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

Tobin, John (Bethel Park, PA)

1989-01-01T23:59:59.000Z

38

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

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

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

39

Dynamic Contact Failure of Two Brittle Particles under Compression  

Science Conference Proceedings (OSTI)

This method allow the particle fracturing behavior to be imaged through the specimen thickness without the disturbance from the impact-induced dust. The dust ...

40

Dust Charging and Transport on Surfaces  

Science Conference Proceedings (OSTI)

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

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

2011-11-29T23:59:59.000Z

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


41

Propagation of nonlinear dust magnetoacoustic waves in cylindrical geometry  

SciTech Connect

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

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

2011-12-15T23:59:59.000Z

42

Dust trajectory sensor: Accuracy and data analysis  

Science Conference Proceedings (OSTI)

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

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

2011-10-15T23:59:59.000Z

43

Dust Studies in DIII-D and TEXTOR  

SciTech Connect

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

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

2009-02-17T23:59:59.000Z

44

Air Breathing Direct Methanol Fuel Cell  

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

Air Breathing Direct Methanol Fuel Cell Air Breathing Direct Methanol Fuel Cell Air Breathing Direct Methanol Fuel Cell An air breathing direct methanol fuel cell is provided with a membrane electrode assembly, a conductive anode assembly that is permeable to air and directly open to atmospheric air, and a conductive cathode assembly that is permeable to methanol and directly contacting a liquid methanol source. Available for thumbnail of Feynman Center (505) 665-9090 Email Air Breathing Direct Methanol Fuel Cell An air breathing direct methanol fuel cell is provided with a membrane electrode assembly, a conductive anode assembly that is permeable to air and directly open to atmospheric air, and a conductive cathode assembly that is permeable to methanol and directly contacting a liquid methanol

45

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

SciTech Connect

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

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

2013-05-28T23:59:59.000Z

46

Breath beat, heart beat: Intoning the rhizome.  

E-Print Network (OSTI)

??Breath Beat, Heart Beat: Intoning the Rhizome is a collection of nonfiction lyric essays written as a spiral of moments. Moments that illuminate connections. Connections… (more)

Pett, Sarah Ann Kloewer

2009-01-01T23:59:59.000Z

47

Dust-feed mechanism  

DOE Patents (OSTI)

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

Milliman, E.M.

1981-04-06T23:59:59.000Z

48

Dust feed mechanism  

DOE Patents (OSTI)

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

Milliman, Edward M. (Benton City, WA)

1984-01-01T23:59:59.000Z

49

STUDY OF CHARACTERIZATION OF SUBMICRON COAL PARTICLES DISPERSED IN AIR AND CAPTURE OF COAL PARTICLES BY WATER DROPS IN A SCRUBBING COLUMN.  

E-Print Network (OSTI)

??Present day water spray based dust removal technologies do not effectively remove respirable submicron coal and silica dust particles in the underground coal mines causing… (more)

Chakravorty, Utshab

2012-01-01T23:59:59.000Z

50

Protective supplied breathing air garment  

DOE Patents (OSTI)

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

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

1984-07-10T23:59:59.000Z

51

Protective supplied breathing air garment  

DOE Patents (OSTI)

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

Childers, Edward L. (Lakewood, CO); von Hortenau, Erik F. (Golden, CO)

1984-07-10T23:59:59.000Z

52

Secondary Electron Emission from Dust and Its Effect on Charging  

Science Conference Proceedings (OSTI)

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

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

2011-11-29T23:59:59.000Z

53

Airvest's Breath of Fresh Air  

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

7 7 The Cutting Edge: Airvest's Breath of Fresh Air Spray booths are a common sight in the industrial sector. Designed to remove pollutants during industrial processes such as spray painting or welding, a booth is a rectangular enclosure open on one side where the worker stands, and equipped on the opposite wall with a fan and filter arrangement to suck away the dirty air. The full-size mannequin in these photographs simulates a worker in a spray booth facing the exhaust filters. In experiments designed by LBL researcher Ashok Gadgil, smoke was released in front of the mannequin to simulate the spraying of paint in the booth. The photo on the left shows the spray booth during standard operation. The smoke-representing a pollutant-is entrained in the eddy that forms in

54

The Influence of Dust on the Absorptivity of Radiant Barriers  

E-Print Network (OSTI)

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

Noboa, Homero L.

1993-08-01T23:59:59.000Z

55

Dust Combustion Safety Issues for Fusion Applications  

SciTech Connect

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

L. C. Cadwallader

2003-05-01T23:59:59.000Z

56

He Puff System For Dust Detector Upgrade  

SciTech Connect

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

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

2010-10-01T23:59:59.000Z

57

Applications of high-speed dust injection to magnetic fusion  

Science Conference Proceedings (OSTI)

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

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

2012-08-08T23:59:59.000Z

58

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

Science Conference Proceedings (OSTI)

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

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

2011-11-29T23:59:59.000Z

59

Misers gold dust collection and cloud characterization  

SciTech Connect

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

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

1991-01-01T23:59:59.000Z

60

Iron mobilization in North African dust.  

SciTech Connect

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

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

2011-01-01T23:59:59.000Z

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


61

Lunar dust transport and potential interactions with power system components  

DOE Green Energy (OSTI)

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

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

1991-11-01T23:59:59.000Z

62

The Smart Dust Project  

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

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

63

The Dust Tail of Asteroid (3200) Phaethon  

E-Print Network (OSTI)

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

Jewitt, David; Agarwal, Jessica

2013-01-01T23:59:59.000Z

64

VP 100: Illinois Wind Farm Breathes New Life Into Businesses...  

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

Illinois Wind Farm Breathes New Life Into Businesses VP 100: Illinois Wind Farm Breathes New Life Into Businesses September 23, 2010 - 12:46pm Addthis The Streator Cayuga Ridge...

65

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

Science Conference Proceedings (OSTI)

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

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

2012-07-15T23:59:59.000Z

66

Air breathing direct methanol fuel cell  

DOE Patents (OSTI)

An air breathing direct methanol fuel cell is provided with a membrane electrode assembly, a conductive anode assembly that is permeable to air and directly open to atmospheric air, and a conductive cathode assembly that is permeable to methanol and directly contacting a liquid methanol source.

Ren, Xiaoming (Los Alamos, NM)

2002-01-01T23:59:59.000Z

67

Influence of Dust on the Emissivity of Radiant Barriers  

E-Print Network (OSTI)

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

Noboa, Homero L.

1991-12-01T23:59:59.000Z

68

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

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

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

69

Radiative Forcing of Climate By Ice-Age Atmospheric Dust  

E-Print Network (OSTI)

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

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

2003-01-01T23:59:59.000Z

70

INTERPRETATION OF (596) SCHEILA'S TRIPLE DUST TAILS  

Science Conference Proceedings (OSTI)

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

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

2011-11-15T23:59:59.000Z

71

Electrostatic dust detector  

DOE Patents (OSTI)

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

Skinner, Charles H. (Lawrenceville, NJ)

2006-05-02T23:59:59.000Z

72

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

SciTech Connect

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

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

2012-01-15T23:59:59.000Z

73

INTERSTELLAR DUST MODULE FOR THE ESA METEOROID MODEL  

E-Print Network (OSTI)

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

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

2001-01-01T23:59:59.000Z

74

Graphite Dust Deflagration  

Science Conference Proceedings (OSTI)

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

2007-03-27T23:59:59.000Z

75

Graphite Dust Deflagration  

Science Conference Proceedings (OSTI)

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

2007-10-03T23:59:59.000Z

76

Protective supplied-breathing-air garment  

DOE Patents (OSTI)

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

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

1982-05-28T23:59:59.000Z

77

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  

Science Conference Proceedings (OSTI)

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

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

2009-12-10T23:59:59.000Z

78

Fractal dust grains in plasma  

Science Conference Proceedings (OSTI)

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

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

2012-09-15T23:59:59.000Z

79

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

SciTech Connect

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

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

1988-01-01T23:59:59.000Z

80

Determining inert content in coal dust/rock dust mixture  

DOE Patents (OSTI)

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

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

1989-01-01T23:59:59.000Z

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


81

Dust control for draglines  

SciTech Connect

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

Grad, P.

2009-09-15T23:59:59.000Z

82

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

Science Conference Proceedings (OSTI)

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

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

2011-03-15T23:59:59.000Z

83

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

SciTech Connect

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

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

2011-01-20T23:59:59.000Z

84

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

Science Conference Proceedings (OSTI)

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

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

2011-05-15T23:59:59.000Z

85

UHF measurement of breathing and heartbeat at a distance  

Science Conference Proceedings (OSTI)

The detection of breathing and heartbeat from a distance is important for medical triage and mass casualty events as well as routine monitoring of higher-risk patients. Typical approaches include wiring up patients to devices and wearable devices, but ... Keywords: UHF, breathing, heartbeat, radar

Jerry Silvious; David Tahmoush

2010-01-01T23:59:59.000Z

86

Delaware Company Breathes New Life into Old Post Office Building |  

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

Delaware Company Breathes New Life into Old Post Office Building Delaware Company Breathes New Life into Old Post Office Building Delaware Company Breathes New Life into Old Post Office Building November 26, 2013 - 12:51pm Addthis Thanks to the Energy Department, Delaware-based Brandywine CAD Design was able to breathe new life into a local historic building while saving on its energy costs. | Photo courtesy of Brandywine CAD Design. Thanks to the Energy Department, Delaware-based Brandywine CAD Design was able to breathe new life into a local historic building while saving on its energy costs. | Photo courtesy of Brandywine CAD Design. Christina Stowers Communications Specialist in the Office of Weatherization and Intergovernmental Program What are the key facts? Delaware company Brandywine CAD Design, Inc., (B-CAD) purchased a

87

Aspiration tests in aqueous foam using a breathing simulator  

SciTech Connect

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

Archuleta, M.M.

1995-12-01T23:59:59.000Z

88

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

Science Conference Proceedings (OSTI)

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

Qingfang Jiang; Ming Liu; James D. Doyle

2011-01-01T23:59:59.000Z

89

Dust and Black Carbon in Seasonal Snow Across Northern China  

Science Conference Proceedings (OSTI)

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

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

2011-02-01T23:59:59.000Z

90

ALPHA ATTENUATION DUE TO DUST LOADING  

SciTech Connect

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

Dailey, A; Dennis Hadlock, D

2007-08-09T23:59:59.000Z

91

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

Science Conference Proceedings (OSTI)

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

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

2010-09-20T23:59:59.000Z

92

Dust in Protoplanetary Disks  

E-Print Network (OSTI)

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

Chiang, E I

2003-01-01T23:59:59.000Z

93

Dust in Protoplanetary Disks  

E-Print Network (OSTI)

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

E. I. Chiang

2003-09-08T23:59:59.000Z

94

A Dust Prediction System with TOMS Initialization  

Science Conference Proceedings (OSTI)

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

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

2002-09-01T23:59:59.000Z

95

Climate Response to Soil Dust Aerosols  

Science Conference Proceedings (OSTI)

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

R. L. Miller; I. Tegen

1998-12-01T23:59:59.000Z

96

Microfabricated breath sensor based on carbon nanotubes for respiration monitoring  

Science Conference Proceedings (OSTI)

A microfabricated breath sensor based on multi-walled carbon nanotubes (MWCNTs) has been designed, developed and tested. This sensor has a simple capacitor structure, including a pair of metal electrodes fabricated by micromachining, which are then coated ...

Hai Liu; Xiaohang Chen; Dong Xu; Zhongyu Hou; Yafei Zhang

2009-01-01T23:59:59.000Z

97

Breathing HRV by the Concept of AC Ventilation  

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

Breathing HRV by the Concept of AC Ventilation Breathing HRV by the Concept of AC Ventilation Speaker(s): Hwataik Han Date: July 10, 2007 - 12:00pm Location: 90-3122 Seminar Host/Point of Contact: Thomas McKone Heat recovery ventilators are frequently used to save heating/cooling loads of buildings for ventilation. There are several types of HRV's, including a parallel plate type, a rotary type, a capillary type, and a heat pipe type. The breathing HRV is a heat recovery ventilator of a new kind using the concept of alternating-current ventilation. The AC ventilation is the ventilation with the airflow directions reversed periodically. It has an advantage of using a single duct system, for both supply and exhaust purposes. In order to develop a breathing HRV system, the thermal recovery performance should be investigated depending on many parameters, such as

98

Whole-heart magnetic resonance coronary angiography with multiple breath-holds and automatic breathing-level tracking  

Science Conference Proceedings (OSTI)

Whole-heart (WH) magnetic resonance coronary angiography (MRCA) studies are usually performed during free breathing while monitoring the position of the diaphragm with real-time motion correction. However

Shigehide Kuhara; Ayako Ninomiya; Tomohisa Okada; Shotaro Kanao; Toshikazu Kamae; Kaori Togashi

2010-01-01T23:59:59.000Z

99

Global dust model intercomparison in AeroCom phase I  

Science Conference Proceedings (OSTI)

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

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

2011-08-18T23:59:59.000Z

100

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

Science Conference Proceedings (OSTI)

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

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

2012-09-26T23:59:59.000Z

Note: This page contains sample records for the topic "breathe dust particles" from the National Library of EnergyBeta (NLEBeta).
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101

Particle impact damping: influence of material and size  

E-Print Network (OSTI)

In this study, particle impact damping is measured for a cantilever beam with a particle-filled enclosure attached to its free end. Many particle materials are tested: lead spheres, steel spheres, glass spheres, tungsten carbide pellets, lead dust, steel dust, and sand. The effects of particle size are also investigated. Particle diameters are varied from about 0.2 mm to 3 mm. The experimental data collected is offered as a resourceful database for future development of an analytical model of particle impact damping.

Marhadi, Kun Saptohartyadi

2003-12-01T23:59:59.000Z

102

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

Science Conference Proceedings (OSTI)

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

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

2003-04-01T23:59:59.000Z

103

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

E-Print Network (OSTI)

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

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

2011-01-01T23:59:59.000Z

104

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

Science Conference Proceedings (OSTI)

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

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

2011-11-15T23:59:59.000Z

105

New insights into single-particle mixing state using aircraft aerosol time-of-flight mass spectrometry  

E-Print Network (OSTI)

K, and S during combustion of annual biomass, Energy Fuels,spherical combustion particles from biomass burning usingsuch as biomass burning, fossil fuel combustion, and dust

Pratt, Kerri Anne

2009-01-01T23:59:59.000Z

106

Growth of Dust as the Initial Step Toward Planet Formation  

E-Print Network (OSTI)

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

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

2006-02-28T23:59:59.000Z

107

A Simple Thermodynamical Theory for Dust Devils  

Science Conference Proceedings (OSTI)

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

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

1998-11-01T23:59:59.000Z

108

Adding coal dust to coal batch  

Science Conference Proceedings (OSTI)

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

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

2009-05-15T23:59:59.000Z

109

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

SciTech Connect

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

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

2011-07-15T23:59:59.000Z

110

Novel methods for respirable dust removal. Final report  

SciTech Connect

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

1980-09-01T23:59:59.000Z

111

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

SciTech Connect

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

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

2012-08-15T23:59:59.000Z

112

Electrostatic Transport and Manipulation of Lunar Soil and Dust  

SciTech Connect

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

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

2008-01-21T23:59:59.000Z

113

Infrared emission from interplanetary dust  

Science Conference Proceedings (OSTI)

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

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

1989-02-01T23:59:59.000Z

114

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

115

Volumetric measurements of a spatially growing dust acoustic wave  

Science Conference Proceedings (OSTI)

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

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

2012-11-15T23:59:59.000Z

116

GRAIN SORTING IN COMETARY DUST FROM THE OUTER SOLAR NEBULA  

SciTech Connect

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

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

2012-12-01T23:59:59.000Z

117

Dust negative ion acoustic shock waves considering dust size distribution effect  

Science Conference Proceedings (OSTI)

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

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

2012-11-15T23:59:59.000Z

118

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

E-Print Network (OSTI)

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

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

2010-01-01T23:59:59.000Z

119

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

SciTech Connect

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

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

2010-12-20T23:59:59.000Z

120

A Model for Long-Range Transport of Desert Dust  

Science Conference Proceedings (OSTI)

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

Slobodan Ni?kovi?; Srdjan Dobri?i?

1996-11-01T23:59:59.000Z

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


121

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

Science Conference Proceedings (OSTI)

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

Martin, A N

2009-01-27T23:59:59.000Z

122

Dust-acoustic filamentation of a current-driven dusty plasma  

Science Conference Proceedings (OSTI)

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

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

2011-06-15T23:59:59.000Z

123

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

E-Print Network (OSTI)

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

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

2013-01-24T23:59:59.000Z

124

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

E-Print Network (OSTI)

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

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

2013-01-01T23:59:59.000Z

125

Heavy metals hazardous components of Eaf dust  

Science Conference Proceedings (OSTI)

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

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

2011-02-01T23:59:59.000Z

126

Observing Cold Dust with Herschel / SPIRE  

Science Conference Proceedings (OSTI)

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

Bernhard Schulz; The SPIRE Consortium

2010-01-01T23:59:59.000Z

127

Measurement of nicotine in household dust  

Science Conference Proceedings (OSTI)

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

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

2008-11-15T23:59:59.000Z

128

Brownian Motion of Stars, Dust, and Invisible Matter  

E-Print Network (OSTI)

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

Edmund Bertschinger

2006-08-28T23:59:59.000Z

129

Composition and Reactions of Atmospheric Aerosol Particles  

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

Composition and Reactions of Composition and Reactions of Atmospheric Aerosol Particles Composition and Reactions of Atmospheric Aerosol Particles Print Wednesday, 29 June 2005 00:00 Microscopic aerosol particles in the atmosphere contain carbonaceous components from mineral dust and combustion emissions released from around the world. How long these tiny particles remain in the atmosphere can have a huge impact on the global climate. Measurements based on high-resolution scanning transmission x-ray images obtained at the ALS have revealed chemical reactions on and in atmospheric aerosol particles that caused particle growth while changing organic composition by 13 to 24% per day, an oxidation rate significantly slower than is currently used in atmospheric models. Since oxidation has a strong effect on particle lifetime in the atmosphere, these results will help climate scientists refine the computer models used to predict climate change.

130

Composition and Reactions of Atmospheric Aerosol Particles  

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

Composition and Reactions of Atmospheric Aerosol Particles Print Composition and Reactions of Atmospheric Aerosol Particles Print Microscopic aerosol particles in the atmosphere contain carbonaceous components from mineral dust and combustion emissions released from around the world. How long these tiny particles remain in the atmosphere can have a huge impact on the global climate. Measurements based on high-resolution scanning transmission x-ray images obtained at the ALS have revealed chemical reactions on and in atmospheric aerosol particles that caused particle growth while changing organic composition by 13 to 24% per day, an oxidation rate significantly slower than is currently used in atmospheric models. Since oxidation has a strong effect on particle lifetime in the atmosphere, these results will help climate scientists refine the computer models used to predict climate change.

131

Composition and Reactions of Atmospheric Aerosol Particles  

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

Composition and Reactions of Atmospheric Aerosol Particles Print Composition and Reactions of Atmospheric Aerosol Particles Print Microscopic aerosol particles in the atmosphere contain carbonaceous components from mineral dust and combustion emissions released from around the world. How long these tiny particles remain in the atmosphere can have a huge impact on the global climate. Measurements based on high-resolution scanning transmission x-ray images obtained at the ALS have revealed chemical reactions on and in atmospheric aerosol particles that caused particle growth while changing organic composition by 13 to 24% per day, an oxidation rate significantly slower than is currently used in atmospheric models. Since oxidation has a strong effect on particle lifetime in the atmosphere, these results will help climate scientists refine the computer models used to predict climate change.

132

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

Science Conference Proceedings (OSTI)

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

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

2010-06-16T23:59:59.000Z

133

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

E-Print Network (OSTI)

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

Termine, F.; Jordan, S. T.

1985-05-01T23:59:59.000Z

134

Health benefits of particle filtration  

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

Health benefits of particle filtration Health benefits of particle filtration Title Health benefits of particle filtration Publication Type Journal Article Year of Publication 2013 Authors Fisk, William J. Journal Indoor Air Date Published 02/12/2013 Abstract The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percentage improvement in health outcomes is typically modest, e.g., 7% to 25%. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

135

Multiply glazed window and door assemblies with screened breathing passages  

SciTech Connect

This patent describes a multiply glazed, vented window or door assembly comprising: spaced apart glass panes sealably secured perimetrally in parallel side sash members and parallel upper and lower sash members. At least one of the sash members has in its outer surface, a linear groove perimetrally aligned with the space between the panes and further having a breathing port extending from the marginal wall of the groove through to the space between the panes; an elongate flat plate having fine perforations and parallel end flanges projecting generally perpendicularly therefrom, fitting into and sealing off the groove at spaced distances from the port to provide an air circulation manifold under the plate. The plate is sufficiently long to have sufficient perforations to provide a cross-sectional area which correlates with the cross-sectional area of the port; and means for securing the plate in place.

Chludil, S.T.

1987-04-14T23:59:59.000Z

136

Air-breathing fuel cell stacks for portable power applications  

DOE Green Energy (OSTI)

Increasing attention is being directed towards polymer electrolyte fuel cells as battery replacements because of their potentially superior energy densities and the possibility of `mechanical` refueling. On the low end of the power requirement scale (ca. 10 W), fuel cells can compete with primary and secondary batteries only if the fuel cell systems are simple, inexpensive, and reliable. Considerations of cost and simplicity (and minimal parasitic power) discourage the use of conventional performance enhancing subsystems (e.g., humidification, cooling, or forced-reactant flow). We are developing a stack design that is inherently self-regulating to allow effective operation without the benefit of such auxiliary components. The air cathode does not use forced flow to replenish the depleted oxygen. Instead, the oxygen in the air must diffuse into the stack from the periphery of the unit cells. For this reason the stack is described as `air-breathing.` This configuration limits the ability of water to escape which prevents the polymer electrolyte membranes from drying out, even at relatively high continuous operation temperatures (+60 degrees C). This results in stacks with reliable and stable performance. This air-breathing configuration assumes a unique stack geometry that utilizes circular flow-field plates with an annular hydrogen feed manifold and the single tie-bolt extending up through the central axis of the stack. With this geometry, the hydrogen supply to the unit cells is radially outward, and the air supply is from the periphery inward. This configuration has several advantages. The entire periphery is free to air access and allows greater heat conduction to enhance cooling. Furthermore, all of the components in the stack (e.g., the flow-fields, seals and membrane/electrode assemblies), are radially symmetrical, so part fabrication is simple and the entire system is potentially low-cost. Lastly, this configuration is compact and lightweight.

Wilson, M.S.; DeCaro, D.; Neutzler, J.K.; Zawodzinski, C.; Gottesfeld, S.

1996-10-01T23:59:59.000Z

137

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

SciTech Connect

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

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

2012-09-20T23:59:59.000Z

138

Pebble Bed Reactor Dust Production Model  

SciTech Connect

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

Abderrafi M. Ougouag; Joshua J. Cogliati

2008-09-01T23:59:59.000Z

139

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

Science Conference Proceedings (OSTI)

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

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

1982-06-01T23:59:59.000Z

140

Particle separation  

DOE Patents (OSTI)

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

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

2011-04-26T23:59:59.000Z

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


141

Laboratory Measurements and Model Sensitivity Studies of Dust Deposition Ice Nucleation  

Science Conference Proceedings (OSTI)

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

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

2012-08-16T23:59:59.000Z

142

Dust Acoustic Shock Waves in Adiabatic Hot Dusty Plasmas  

Science Conference Proceedings (OSTI)

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

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

2011-03-30T23:59:59.000Z

143

Dust Lofting and Ingestion by Supercell Storms  

Science Conference Proceedings (OSTI)

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

Robert B. Seigel; Susan C. van den Heever

2012-05-01T23:59:59.000Z

144

Dust Intrusion Events into the Mediterranean Basin  

Science Conference Proceedings (OSTI)

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

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

1991-08-01T23:59:59.000Z

145

Thermo-Oxidation of Tokamak Carbon Dust  

Science Conference Proceedings (OSTI)

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

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

2008-04-01T23:59:59.000Z

146

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

E-Print Network (OSTI)

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

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

2009-01-01T23:59:59.000Z

147

A Particle-Surface-Area-Based Parameterization of Immersion Freezing on Desert Dust Particles  

Science Conference Proceedings (OSTI)

In climate and weather models, the quantitative description of aerosol and cloud processes relies on simplified assumptions. This contributes major uncertainties to the prediction of global and regional climate change. Therefore, models need good ...

Monika Niemand; Ottmar Möhler; Bernhard Vogel; Heike Vogel; Corinna Hoose; Paul Connolly; Holger Klein; Heinz Bingemer; Paul DeMott; Julian Skrotzki; Thomas Leisner

2012-10-01T23:59:59.000Z

148

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

Science Conference Proceedings (OSTI)

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

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

2006-10-01T23:59:59.000Z

149

Estimating Environmental Exposures to Indoor Contaminants using Residential-Dust Samples  

E-Print Network (OSTI)

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

Whitehead, Todd Patrick

2011-01-01T23:59:59.000Z

150

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

Science Conference Proceedings (OSTI)

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

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

2012-10-10T23:59:59.000Z

151

Harrison transformation of hyperelliptic solutions and charged dust disks  

E-Print Network (OSTI)

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

C. Klein

2005-12-22T23:59:59.000Z

152

Particle Lifetimes  

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

Reviewing Particle Lifetimes Reviewing Particle Lifetimes The lifetimes of elementary particles are statistical in nature. In a given sample, one particle might decay immediately, another in 1 nanosecond, yet another after 10 milliseconds, and still another in 50 years. What we call the lifetime is the time it takes for a sample to decay so 1/e (~30%) of the sample is left; after 2 lifetimes, 1/e2 of the sample is left, and so on. Take, for example, a sample of cosmic ray muons produced in the upper atmosphere. These muons, when observed at (relative) rest in the laboratory, have a mean lifetime T. Now, since particle decay is statistical in nature, the number of undecayed particles after a given time is a negative exponential function: N(t) = No e-t/T where N(t) is the number of muons at time t, No is the initial number of

153

PARTICLE ACCELERATOR  

DOE Patents (OSTI)

A fixed-field alternating gradient accelerator for simultaneous acceleration of two particle beams in opposite directions is described. (T.R.H.)

Ohkawa, T.

1959-06-01T23:59:59.000Z

154

Ethanol Blends and Engine Operating Strategy Effects on Light-Duty Spark-Ignition Engine Particle Emissions  

Science Conference Proceedings (OSTI)

Spark ignition (SI) engines with direct injection (DI) fueling can improve fuel economy and vehicle power beyond that of port fuel injection (PFI). Despite this distinct advantage, DI fueling often increases particle emissions such that SI exhaust may be subject to future particle emissions regulations. Challenges in controlling particle emissions arise as engines encounter varied fuel composition such as intermediate ethanol blends. Furthermore, modern engines are operated using unconventional breathing strategies with advanced cam-based variable valve actuation systems. In this study, we investigate particle emissions from a multi-cylinder DI engine operated with three different breathing strategies, fueling strategies and fuels. The breathing strategies are conventional throttled operation, early intake valve closing (EIVC) and late intake valve closing (LIVC); the fueling strategies are single injection DI (sDI), multi-injection DI (mDI), and PFI; and the fuels are emissions certification gasoline, E20 and E85. The results indicate the dominant factor influencing particle number concentration emissions for the sDI and mDI strategies is the fuel injection timing. Overly advanced injection timing results in particle formation due to fuel spray impingement on the piston, and overly retarded injection timing results in particle formation due to poor fuel and air mixing. In addition, fuel type has a significant effect on particle emissions for the DI fueling strategies. Gasoline and E20 fuels generate comparable levels of particle emissions, but E85 produces dramatically lower particle number concentration. The particle emissions for E85 are near the detection limit for the FSN instrument, and particle number emissions are one to two orders of magnitude lower for E85 relative to gasoline and E20. We found PFI fueling produces very low levels of particle emissions under all conditions and is much less sensitive to engine breathing strategy and fuel type than the DI fueling strategies. The particle number-size distributions for PFI fueling are of the same order for all of the breathing strategies and fuel types and are one to two orders lower than for the sDI fuel injection strategy with gasoline and E20. Remarkably, the particle emissions for E85 under the sDI fueling strategy are similar to particle emissions with a PFI fueling strategy. Thus by using E85, the efficiency and power advantages of DI fueling can be gained without generating high particle emissions.

Szybist, James P [ORNL; Youngquist, Adam D [ORNL; Barone, Teresa L [ORNL; Storey, John Morse [ORNL; Moore, Wayne [Delphi; Foster, Matthew [Delphi; Confer, Keith [Delphi

2011-01-01T23:59:59.000Z

155

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

Science Conference Proceedings (OSTI)

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

Robert C. Brown; Gerald M. Colver

2002-10-31T23:59:59.000Z

156

Retention of aerosol particles in the human respiratory tract as a function of particle radius  

SciTech Connect

A water--glycerol aerosol of /sup 24/NaCl (approx. 500 mg/m/sup 3/) was inhaled by 7 volunteers to assess retention of monodispersed aerosols in human respiratory tract. Various particle sizes were tested; dispersion method was thought to be effective. Alveolar retention shows two peaks in the 0.3 to 1 ..mu..m range. Maximum alveolar retention is approx. 45%. Total retention decreased linearly with breathing rate, increased linearly with radius from 0.2 to 1.6 ..mu..m.

Wilson, I.B.; LaMer, V.K.

1948-01-01T23:59:59.000Z

157

Impact of Transport Schemes on Modeled Dust Concentrations  

Science Conference Proceedings (OSTI)

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

Maria Raffaella Vuolo; Laurent Menut; Hélène Chepfer

2009-06-01T23:59:59.000Z

158

Historical Records of Asian Dust Events (Hwangsa) in Korea  

Science Conference Proceedings (OSTI)

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

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

2008-06-01T23:59:59.000Z

159

Pseudopotentials of the particles interactions in complex plasmas  

SciTech Connect

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

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

2011-10-15T23:59:59.000Z

160

Infrared Extinction by Aggregates of SiC Particles  

E-Print Network (OSTI)

Particle shape and aggregation have a strong influence on the spectral profiles of infrared phonon bands of solid dust grains. In this paper, we use a discrete dipole approximation, a cluster-of-spheres code following the Gerardy-Ausloos approach and a T-matrix method for calculating IR extinction spectra of aggregates of spherical silicon carbide (SiC) particles. We compare the results obtained with the three different methods and discuss differences in the band profiles.

Anja C. Andersen; Harald Mutschke; Thomas Posch

2005-11-11T23:59:59.000Z

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


161

Identification of Arsenic Species in Coal Ash Particles  

Science Conference Proceedings (OSTI)

Identification of the chemical species and compounds of arsenic in individual coal fly ash particles will help provide a scientifically sound basis for assessing health risks from inhalation of these particles. This report presents the results of an analytical chemistry study of coal-combustion ash, with some work also completed on oil-combustion ash and copper smelter dust collected from several sources in the United States and Europe. Results showed that most arsenic is present on the surface of coal a...

1998-08-13T23:59:59.000Z

162

A Model for Saharan Dust Transport  

Science Conference Proceedings (OSTI)

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

Guillaume A. d'Almeida

1986-07-01T23:59:59.000Z

163

Dust Mitigation Methods for Coal Combustion Products  

Science Conference Proceedings (OSTI)

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

2013-08-27T23:59:59.000Z

164

Radiative Heating Rates for Saharan Dust  

Science Conference Proceedings (OSTI)

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

Toby N. Carlson; Stanley G. Benjamin

1980-01-01T23:59:59.000Z

165

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

Science Conference Proceedings (OSTI)

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

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

1981-12-01T23:59:59.000Z

166

Geothermal Systems are a Breath of Fresh Air for Illinois School District |  

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

Geothermal Systems are a Breath of Fresh Air for Illinois School Geothermal Systems are a Breath of Fresh Air for Illinois School District Geothermal Systems are a Breath of Fresh Air for Illinois School District May 24, 2010 - 11:01am Addthis Each classroom has a geothermal unit installed. Although large, the units blend into surroundings and don’t produce excess noise. | Photo Courtesy of Sterling Public Schools Each classroom has a geothermal unit installed. Although large, the units blend into surroundings and don't produce excess noise. | Photo Courtesy of Sterling Public Schools Lindsay Gsell Superintendent Tad Everett had two priorities when deciding on a new system to replace the aging oil-based boiler heating and cooling systems for the seven schools in his district: improving learning environments and saving

167

Geothermal Systems are a Breath of Fresh Air for Illinois School District |  

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

Geothermal Systems are a Breath of Fresh Air for Illinois School Geothermal Systems are a Breath of Fresh Air for Illinois School District Geothermal Systems are a Breath of Fresh Air for Illinois School District May 24, 2010 - 11:01am Addthis Each classroom has a geothermal unit installed. Although large, the units blend into surroundings and don’t produce excess noise. | Photo Courtesy of Sterling Public Schools Each classroom has a geothermal unit installed. Although large, the units blend into surroundings and don't produce excess noise. | Photo Courtesy of Sterling Public Schools Lindsay Gsell Superintendent Tad Everett had two priorities when deciding on a new system to replace the aging oil-based boiler heating and cooling systems for the seven schools in his district: improving learning environments and saving

168

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

Science Conference Proceedings (OSTI)

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

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

2012-12-15T23:59:59.000Z

169

Online Particle Physics Information - Particles & Properties...  

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

Particles & Properties Data Review of Particle Physics (RPP) A biennial comprehensive review summarizing much of the known data about the field of particle physics produced by the...

170

The Particle Adventure | Particle decays and annihiliations ...  

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

virtual particles. Virtual particles do not violate the conservation of energy. The kinetic energy plus mass of the initial decaying particle and the final decay products is...

171

The Particle Adventure | Accelerators and Particle Detectors  

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

Waves and particles The world's meterstick Mass and energy Energy-mass conversion Accelerators How to obtain particles to accelerate Accelerating particles Accelerating...

172

Review of Particle Physics  

E-Print Network (OSTI)

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

Nakamura, Kenzo

2010-01-01T23:59:59.000Z

173

Poster — Thur Eve — 26: Interfraction reproducibility of heart position during breast irradiation using Active Breathing Control  

Science Conference Proceedings (OSTI)

The moderate deep?inspiration breath hold (mDIBH) technique using the Active Breathing Coordinator (ABC) from Elekta is used in our clinic to lower the heartdose during left breast irradiations. The purpose of this work was to investigate the interfraction reproducibility of the heart to chest distance during these treatments and to evaluate the dosimetric effect of any changes in the heart position. Daily CBCTimages were available for 5 patients who had been treated with ABC tangents and a cavity boost. On these images

D Comsa; B Zhang; D Mosely; I Yeung

2012-01-01T23:59:59.000Z

174

How to Live Well Without Owning a Car: Save Money, Breathe Easier, and Get More Mileage Out of Life By Chris Balish  

E-Print Network (OSTI)

Without Owning a Car: Save Money, Breathe Easier, and GetWithout Owning a Car: Save Money, Breathe Easier, an Getyou can save a ton of money by not owning. One assumption he

Wong, Carleton

2008-01-01T23:59:59.000Z

175

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

E-Print Network (OSTI)

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

Merrick, William (William F. W.)

2005-01-01T23:59:59.000Z

176

How to Live Well Without Owning a Car: Save Money, Breathe Easier, and Get More Mileage Out of Life By Chris Balish  

E-Print Network (OSTI)

Live Well Without Owning a Car: Save Money, Breathe Easier,Live Well Without Owning a Car: Save Money, Breathe Easier,mere thought of not owning a car in the United States today

Wong, Carleton

2008-01-01T23:59:59.000Z

177

Elementary Particles  

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

Elementary Particles Elementary Particles Elementary Particles Detectors Accelerators Visit World Labs For Children - for younger people Electric Forces & Fields For Children The Electric Force For Children Electric Force Fields For Children Charges and Fields For Children Vibrating Charges and Electromagnetic Waves Electrons For Older People The Discovery of the Electron Traveling Waves For Older People Waves and Wave-Like Motion For Children Catch the Wave For Children Vibrating Charges and Electromagnetic Waves For Children Electromagnetic Waves Standing Waves For Older People Physics 128 Lecture Standing Waves For Older People Resonance in Strings and Springs For Older People Standing Wave - 1st Harmonic For Older People Standing Wave - 2nd Harmonic Atom For Older People Bohr Atom

178

Carbon particles  

DOE Patents (OSTI)

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.

Hunt, Arlon J. (Oakland, CA)

1984-01-01T23:59:59.000Z

179

Trillion Particles,  

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

Trillion Trillion Particles, 120,000 cores, and 350 TBs: Lessons Learned from a Hero I/O Run on Hopper Surendra Byna ∗ , Andrew Uselton ∗ , Prabhat ∗ , David Knaak † , and Yun (Helen) He ∗ ∗ Lawrence Berkeley National Laboratory, USA. Email: {sbyna, acuselton, prabhat, yhe}@lbl.gov † Cray Inc., USA. Email: knaak@cray.com Abstract-Modern petascale applications can present a variety of configuration, runtime, and data management challenges when run at scale. In this paper, we describe our experiences in running VPIC, a large-scale plasma physics simulation, on the NERSC production Cray XE6 system Hopper. The simulation ran on 120,000 cores using ∼80% of computing resources, 90% of the available memory on each node and 50% of the Lustre scratch file system. Over two trillion particles were simulated for 23,000 timesteps, and 10 one-trillion particle dumps, each ranging between

180

3/14/08 5:42 PMIEEE Spectrum: New Sensor Shows Electric Nature of Dust Devils Page 1 of 3http://spectrum.ieee.org/mar08/6030  

E-Print Network (OSTI)

that makes it into the atmosphere. Dust is part of the family of aerosols-- suspended particles or molecules in the air--which includes water vapor and soot from coal combustion. Aerosols absorb or reflect radiation and the negative charges carried by wind-blown particles colliding with the sensor. Though it remains unclear just

Michigan, University of

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


181

Milky Way Tomography IV: Dissecting Dust  

SciTech Connect

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

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

2011-11-01T23:59:59.000Z

182

PARTICLE ACCELERATOR  

DOE Patents (OSTI)

ABS>A combination of two accelerators, a cyclotron and a ring-shaped accelerator which has a portion disposed tangentially to the cyclotron, is described. Means are provided to transfer particles from the cyclotron to the ring accelerator including a magnetic deflector within the cyclotron, a magnetic shield between the ring accelerator and the cyclotron, and a magnetic inflector within the ring accelerator.

Teng, L.C.

1960-01-19T23:59:59.000Z

183

Carbon isotope fractionation between diet, breath CO2, and bioapatite in different mammals  

E-Print Network (OSTI)

Carbon isotope fractionation between diet, breath CO2, and bioapatite in different mammals Benjamin , M. Denise Dearing c , Beverly L. Roeder b , James R. Ehleringer c a Department of Geology 84112, USA Received 15 November 2004; received in revised form 15 March 2005 Abstract The carbon isotope

Ehleringer, Jim

184

Dust ion-acoustic shock waves in charge varying dusty plasmas with electrons having vortexlike velocity distribution  

Science Conference Proceedings (OSTI)

A weakly nonlinear analysis is carried out to investigate the properties of dust ion-acoustic shock waves in a charge varying dusty plasma with vortexlike electron distribution. We use the ionization model, hot ions with equilibrium streaming speed and a trapped electron charging current derived from the well-known orbit limited motion theory. A new modified Burger equation is derived. Besides nonlinear trapping, this equation involves two kinds of dissipation (the anomalous one inherent to nonadiabatic dust charge fluctuation and the one due to the particle loss and ionization). These two kinds of dissipation can act concurrently. The traveling wave solution has been acquired by employing the modified extended tanh-function method. The shocklike solution is numerically analyzed based on the typical numerical data from laboratory dusty plasma devices. It is found that ion temperature, trapped particles, and weak dissipations significantly modify the shock structures.

Alinejad, H. [Department of Physics, Faculty of Basic Science, Babol University of Technology, Babol 47148-71167 (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha, P.O. Box 55134-441, Maragha 55177-36698 (Iran, Islamic Republic of); Tribeche, M. [Plasma Physics Group (PPG), Theoretical Physics Laboratory (TPL), Faculty of Science-Physics, University of Bab-Ezzouar, USTHB, B.P. 32, El Alia, Algiers (Algeria)

2010-12-15T23:59:59.000Z

185

Accumulated Dose in Liver Stereotactic Body Radiotherapy: Positioning, Breathing, and Deformation Effects  

Science Conference Proceedings (OSTI)

Purpose: To investigate the accumulated dose deviations to tumors and normal tissues in liver stereotactic body radiotherapy (SBRT) and investigate their geometric causes. Methods and Materials: Thirty previously treated liver cancer patients were retrospectively evaluated. Stereotactic body radiotherapy was planned on the static exhale CT for 27-60 Gy in 6 fractions, and patients were treated in free-breathing with daily cone-beam CT guidance. Biomechanical model-based deformable image registration accumulated dose over both the planning four-dimensional (4D) CT (predicted breathing dose) and also over each fraction's respiratory-correlated cone-beam CT (accumulated treatment dose). The contribution of different geometric errors to changes between the accumulated and predicted breathing dose were quantified. Results: Twenty-one patients (70%) had accumulated dose deviations relative to the planned static prescription dose >5%, ranging from -15% to 5% in tumors and -42% to 8% in normal tissues. Sixteen patients (53%) still had deviations relative to the 4D CT-predicted dose, which were similar in magnitude. Thirty-two tissues in these 16 patients had deviations >5% relative to the 4D CT-predicted dose, and residual setup errors (n = 17) were most often the largest cause of the deviations, followed by deformations (n = 8) and breathing variations (n = 7). Conclusion: The majority of patients had accumulated dose deviations >5% relative to the static plan. Significant deviations relative to the predicted breathing dose still occurred in more than half the patients, commonly owing to residual setup errors. Accumulated SBRT dose may be warranted to pursue further dose escalation, adaptive SBRT, and aid in correlation with clinical outcomes.

Velec, Michael, E-mail: michael.velec@rmp.uhn.on.ca [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Institute of Medical Science, University of Toronto, Toronto, ON (Canada); Moseley, Joanne L. [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Craig, Tim [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Dawson, Laura A.; Brock, Kristy K. [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Institute of Medical Science, University of Toronto, Toronto, ON (Canada)

2012-07-15T23:59:59.000Z

186

Dust distribution in disks supplied by small bodies: Is the Beta Pictoris disk a gigantic multi-cometary tail?  

E-Print Network (OSTI)

We have evaluated the spatial distribution of dust in disks supplied by colliding or evaporating bodies spread in a small belt. The gradient of the distribution of dust expelled by radiation pressure is generally steeper than the one observed around \\bp. It follows that, to generate the \\bp\\ disk distribution in such a way, one should extract relatively more small particles in the production process: thanks to radiation forces, these smaller particles have large eccentricities and thus could be seen at very large distances from their injection place. The evaporation process of comet-like bodies moving slowly inwards may yield the necessary particle size distribution. It is interesting to note that this dynamical description is able to account for the main observational properties of the \\bp\\ disk, such as the power law distribution with possibly a change in slope, the asymmetry at large distances, and the total mass, all of which have remained unexplained up to now. If confirmed, this scenario may indicate that the \\bp\\ disk could be looked on as a gigantic multi-cometary tail with its natural constituents: gas and dust.

A. Lecavelier des Etangs; A. Vidal-Madjar; R. Ferlet

1995-08-08T23:59:59.000Z

187

Spatial distribution of the interplanetary dust deduced by infrared observations  

Science Conference Proceedings (OSTI)

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

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

1991-03-01T23:59:59.000Z

188

Dust acoustic shock waves in two temperatures charged dusty grains  

Science Conference Proceedings (OSTI)

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

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

2011-11-15T23:59:59.000Z

189

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

SciTech Connect

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

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

2010-07-15T23:59:59.000Z

190

Upper limit on the gas density in the Beta-Pictoris system: On the effect of gas drag on the dust dynamics  

E-Print Network (OSTI)

We investigate in this paper the effect of gas drag on the dynamics of the dust particles in the edge-on Beta-Pictoris disc in order to derive an upper limit on the mass of gas in this system. Our study is motivated by the large uncertainties on the amount of gas in the Beta-Pictoris disc currently found in the literature. The dust particles are assumed to originate from a colliding annulus of planetesimals peaked around 100AU from the central star as proposed by Augereau et al.(2001). We consider the various gas densities that have been inferred from independent observing techniques and we discuss their impact on the dust dynamics and on the disc profile in scattered light along the midplane. We show that the observed scattered light profile of the disc cannot be properly reproduced if hydrogen gas number density at 117AU exceeds 10**4 cm**-3. This corresponds to an upper limit on the total gas mass of about 0.4 Mearth assuming the gas density profile inferred by Brandeker et al.(2004) and thus to a gas to dust mass ratio smaller than 1. Our approach therefore provides an independent diagnostic for a gas depletion in the Beta-Pictoris system relative to the dust disc. Such an approach could also be used to constrain the gas content of recently identified systems like the edge-on disc around AUmic.

P. Thebault; J. -C Augereau

2005-02-22T23:59:59.000Z

191

Recovering Zinc and Lead from Electric Arc Furnace Dust  

Science Conference Proceedings (OSTI)

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

192

Dust-induced instability in a rotating plasma  

SciTech Connect

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

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

2008-01-15T23:59:59.000Z

193

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

Science Conference Proceedings (OSTI)

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

194

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

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

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

195

MULTIBAND OPTICAL OBSERVATION OF THE P/2010 A2 DUST TAIL  

SciTech Connect

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

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

2012-02-10T23:59:59.000Z

196

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

Science Conference Proceedings (OSTI)

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

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

2012-03-20T23:59:59.000Z

197

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

SciTech Connect

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

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

2011-12-31T23:59:59.000Z

198

Particle swarm optimization with opposite particles  

Science Conference Proceedings (OSTI)

The particle swarm optimization algorithm is a kind of intelligent optimization algorithm. This algorithm is prone to be fettered by the local optimization solution when the particle's velocity is small. This paper presents a novel particle swarm ...

Rujing Wang; Xiaoming Zhang

2005-11-01T23:59:59.000Z

199

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

Science Conference Proceedings (OSTI)

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

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

2012-09-01T23:59:59.000Z

200

The Particle Adventure | Glossary  

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

Charge A quantum number carried by a particle. Determines whether the particle can participate in an interaction process. A particle with electric charge has electrical...

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


201

The Particle Adventure | Glossary  

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

Stable Does not decay. A particle is stable if there exist no processes in which a particle disappears and in its place different particles appear...

202

The Particle Adventure | Glossary  

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

Event What occurs when two particles collide or a single particle decays. Particle theories predict the probabilities of various possible events occurring when many similar...

203

Evolution of Dust Extinction and Supernova Cosmology  

E-Print Network (OSTI)

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

Tomonori Totani; Chiaki Kobayashi

1999-10-04T23:59:59.000Z

204

DUST-DRIVEN WIND FROM DISK GALAXIES  

SciTech Connect

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

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

2011-08-01T23:59:59.000Z

205

Two-Component Dust in Spherically Symmetric Motion  

E-Print Network (OSTI)

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

Haager, G

1997-01-01T23:59:59.000Z

206

Two-Component Dust in Spherically Symmetric Motion  

E-Print Network (OSTI)

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

Gernot Haager

1997-05-02T23:59:59.000Z

207

Dust en-route to Jupiter and the Galilean satellites  

E-Print Network (OSTI)

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

Harald Krueger; Eberhard Gruen

2002-05-28T23:59:59.000Z

208

Constraining oceanic dust deposition using surface ocean dissolved Al  

E-Print Network (OSTI)

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

Moore, Keith

209

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

SciTech Connect

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

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

2009-01-01T23:59:59.000Z

210

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

SciTech Connect

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

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

2011-02-01T23:59:59.000Z

211

Energy conditions, traversable wormholes and dust shells  

E-Print Network (OSTI)

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

Lobo, F S N

2004-01-01T23:59:59.000Z

212

A new method to generate dust with astrophysical properties  

SciTech Connect

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

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

2010-04-21T23:59:59.000Z

213

FROM PLANETESIMALS TO DUST: LOW-GRAVITY EXPERIMENTS ON RECYCLING SOLIDS AT THE INNER EDGES OF PROTOPLANETARY DISKS  

SciTech Connect

Transporting solids of different sizes is an essential process in the evolution of protoplanetary disks and planet formation. Large solids are supposed to drift inward; high-temperature minerals found in comets are assumed to have been transported outward. From low-gravity experiments on parabolic flights, we studied the light-induced erosion of dusty bodies caused by a solid-state greenhouse effect and photophoresis within a dust bed's upper layers. The gravity levels studied were 0.16g, 0.38g, 1g, and 1.7g. The light flux during the experiments was 12 {+-} 2 kW m{sup -2} and the ambient pressure was 6 {+-} 0.9 mbar. Light-induced erosion is strongly gravity dependent, which is in agreement with a developed model. In particular for small dusty bodies ((sub)-planetesimals), efficient erosion is possible at the optically thin inner edges of protoplanetary disks. Light-induced erosion prevents significant parts of a larger body from moving too close to the host star and being subsequently accreted. The small dust produced continues to be subject to photophoresis and is partially transported upward and outward over the surface of the disk; the resulting small dust particles are observed over the disk's lifetime. The fraction of eroded dust participates in subsequent cycles of growth during planetesimal formation. Another fraction of dust might be collected by a body of planetary size if this body is already present close to the disk edge. Either way, light-induced erosion is an efficient recycling process in protoplanetary disks.

De Beule, Caroline; Kelling, Thorben; Wurm, Gerhard; Teiser, Jens; Jankowski, Tim, E-mail: caroline.de-beule@uni-due.de [Universitaet Duisburg-Essen, Fakultaet fuer Physik, Lotharstrasse 1, D-47057 Duisburg (Germany)] [Universitaet Duisburg-Essen, Fakultaet fuer Physik, Lotharstrasse 1, D-47057 Duisburg (Germany)

2013-01-20T23:59:59.000Z

214

The Use of the Active Breathing Coordinator Throughout Radical Non-Small-Cell Lung Cancer (NSCLC) Radiotherapy  

SciTech Connect

Purpose: To assess feasibility and reproducibility of an Active Breathing Coordinator (ABC) used throughout radical radiotherapy for non-small-cell lung cancer, and compare lung dosimetric parameters between free-breathing and ABC plans. Methods and Materials: A total of 18 patients, recruited into an approved study, had free-breathing and ABC breath-hold treatment plans generated. Lung volume, the percentage volume of lung treated to a dose of {>=}20 Gy (V{sub 20}), and mean lung dose (MLD) were compared. Treatment (64 Gy in 32 fractions, 5 days/week) was delivered in breath-hold. Repeat breath-hold computed tomography scans were used to assess change in gross tumor volume (GTV) size and position. Setup error was also measured and potential GTV-planning target volume (PTV) margins calculated. Results: Seventeen of 18 patients completed radiotherapy using ABC daily. Intrafraction tumor position was consistent, but interfraction variation had mean (range) values of 5.1 (0-25), 3.6 (0-9.7), and 3.5 (0-16.6) mm in the superoinferior (SI), right-left (RL), and anteroposterior (AP) directions, respectively. Tumor moved partially outside the PTV in 5 patients. Mean reduction in GTV from planning to end of treatment was 25% (p = 0.003). Potentially required PTV margins were 18.1, 11.9, and 11.9 mm in SI, RL, and AP directions. ABC reduced V{sub 20} by 13% (p = 0.0001), V{sub 13} by 12% (p = 0.001), and MLD by 13% (p < 0.001) compared with free-breathing; lung volume increased by 41% (p < 0.001). Conclusions: Clinically significant movements of GTV were seen during radiotherapy for non-small-cell lung cancer using ABC. Image guidance is recommended with ABC. The use of ABC can reduce dose volume parameters determining lung toxicity, and might allow for equitoxic radiotherapy dose escalation.

Brock, Juliet, E-mail: juliet.brock@icr.ac.uk [Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Downs Road, Sutton, Surrey (United Kingdom); McNair, Helen A.; Panakis, Niki; Symonds-Tayler, Richard; Evans, Phil M.; Brada, Michael [Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Downs Road, Sutton, Surrey (United Kingdom)

2011-10-01T23:59:59.000Z

215

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

Science Conference Proceedings (OSTI)

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

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

2012-03-15T23:59:59.000Z

216

Reducing dust emissions at OAO Alchevskkoks coke battery 10A  

Science Conference Proceedings (OSTI)

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

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

2009-07-15T23:59:59.000Z

217

The Particle Adventure | Particle decays and annihiliations ...  

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

alphabet: (alpha), (beta), and (gamma). Alpha particles are helium nuclei (2 p, 2 n): Beta particles are speedy electrons: Gamma radiation is a high-energy photon: These three...

218

Imitative sequel writing: divine breathings, second part of the Pilgrim's Progress, and the case of T. S. (aka Thomas Sherman)  

E-Print Network (OSTI)

During the period between 1640 and 1700, over forty works were produced by authors identifying themselves as “T. S.” In the field of early modern literary studies, one T. S. has been particularly important to scholars because of this author’s imitative version of John Bunyan’s popular allegory titled The Second Part of the Pilgrim’s Progress (1682). This work by T. S., who has become known as Thomas Sherman, achieves minor success and prompts Bunyan to write his own authentic sequel. My research has uncovered an attribution history that identifies four additional texts—Divine Breathings (circa 1671); Youth’s Tragedy (1671); Youth’s Comedy (1680); Divine Breathings, the Second Part (1680)—and credits all of them to a Thomas Sherman. Of the five works attributed to this author, the most impressive printing history belongs to the earliest offering, Divine Breathings, or a Pious Soul Thirsting after Christ in a Hundred Pathetical Meditations, which appears in over 60 printings from 1671 to 1883 in England, Scotland, and North America. My research scrutinizes this attribution history and raises questions about identifying this T. S. as Thomas Sherman. Based on internal and external evidence, I argue that T. S. is not the author of Divine Breathings but establishes his authorial identity as an imitative writer who actively participates in the genre of Protestant meditational literature by providing sequels (i.e., Divine Breathings …the Second Part and Second Part of the Pilgrim’s Progress).

Garrett, Christopher E.

2007-08-01T23:59:59.000Z

219

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

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

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

220

Aerobiology and the global transport of desert dust  

E-Print Network (OSTI)

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

Ahmad, Sajjad

Note: This page contains sample records for the topic "breathe dust particles" from the National Library of EnergyBeta (NLEBeta).
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221

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

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

222

Saharan Dust Aerosol Radiative Forcing Measured from Space  

Science Conference Proceedings (OSTI)

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

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

2004-07-01T23:59:59.000Z

223

Morphological investigations of fibrogenic action of Estonian oil shale dust  

SciTech Connect

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

Kung, V.A.

1979-06-01T23:59:59.000Z

224

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

Science Conference Proceedings (OSTI)

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

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

1992-02-01T23:59:59.000Z

225

A Case Study of Mobilization and Transport of Saharan Dust  

Science Conference Proceedings (OSTI)

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

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

1988-08-01T23:59:59.000Z

226

Dust Accumulation Biases in PIRATA Shortwave Radiation Records  

Science Conference Proceedings (OSTI)

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

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

2013-07-01T23:59:59.000Z

227

Next Century Challenges: Mobile Networking for "Smart Dust"  

E-Print Network (OSTI)

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

Kahn, Joseph M.

228

Magnetorotational instability in plasmas with mobile dust grains  

SciTech Connect

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

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

2013-03-15T23:59:59.000Z

229

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

SciTech Connect

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

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

1995-02-01T23:59:59.000Z

230

A SPITZER SURVEY FOR DUST IN TYPE IIn SUPERNOVAE  

Science Conference Proceedings (OSTI)

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

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

2011-11-01T23:59:59.000Z

231

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

Science Conference Proceedings (OSTI)

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

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

2012-04-04T23:59:59.000Z

232

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

E-Print Network (OSTI)

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

J. Klacka

2008-07-18T23:59:59.000Z

233

The Particle Adventure  

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

Is this particle really the Higgs... Is this particle really the Higgs Boson? Does it swim and quack like a duck? While decays of this kind had been observed for the new particle...

234

The Particle Adventure | Glossary  

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

Boson A particle that has integer intrinsic angular momentum (spin) measured in units of h-bar (spin 0, 1, 2, ...). All particles are either fermions or bosons. The particles...

235

The Particle Adventure | Glossary  

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

Rest Mass The rest mass (m) of a particle is the mass defined by the energy of the isolated (free) particle at rest, divided by the speed of light squared. When particle physicists...

236

The Particle Adventure | Glossary  

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

Decay A process in which a particle disappears and in its place different particles appear. The sum of the masses of the produced particles is always less than the mass of the...

237

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

Science Conference Proceedings (OSTI)

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

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

1994-07-01T23:59:59.000Z

238

Dust explosion hazards due to blasting of oil shale  

SciTech Connect

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

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

1984-04-01T23:59:59.000Z

239

Development of materials resistant to metal dusting degradation.  

Science Conference Proceedings (OSTI)

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

Natesan, K.; Zeng, Z.

2006-04-24T23:59:59.000Z

240

Secular Instability and Planetesimal Formation in the Dust Layer  

E-Print Network (OSTI)

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

J. Goodman; B. Pindor

1999-12-28T23:59:59.000Z

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


241

HTGR Dust Safety Issues and Needs for Research and Development  

Science Conference Proceedings (OSTI)

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

Paul W. Humrickhouse

2011-06-01T23:59:59.000Z

242

Energy conditions, traversable wormholes and dust shells  

E-Print Network (OSTI)

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

Francisco S. N. Lobo

2004-10-18T23:59:59.000Z

243

Nuclear & Particle Physics Directorate  

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

Nuclear & Particle Physics Directorate Nuclear and Particle Physics (NPP) at BNL comprises the Collider-Accelerator Department (including the NASA Space Radiation Laboratory,...

244

Particle Physics Booklet 2008  

E-Print Network (OSTI)

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

et al., C. Amsler

2008-01-01T23:59:59.000Z

245

Small Particles, Big Impact  

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

Small Particles, Big Impact Small Particles, Big Impact Small-scale effects of Aerosols Add up Over Time August 24, 2011 | Tags: Climate Research, Earth Sciences, Environmental...

246

Glossary Term - Beta Particle  

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

Decay Previous Term (Beta Decay) Glossary Main Index Next Term (Bohr Radius) Bohr Radius Beta Particle Beta particles are either electrons or positrons ejected from the nucleus....

247

Glossary Term - Alpha Particle  

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

Decay Previous Term (Alpha Decay) Glossary Main Index Next Term (Atomic Number) Atomic Number Alpha Particle alphaparticle.gif Produced during alpha decay, an alpha particle is a...

248

The Particle Adventure | Glossary  

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

Virtual Particle A particle that exists only for an extremely brief instant in an intermediary process. Then the Heisenberg Uncertainty Principle allows an apparent violation of...

249

The Particle Adventure | Glossary  

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

Annihilation A process in which a particle meets its corresponding antiparticle and both disappear. The energy appears in some other form, perhaps as a different particle and its...

250

The Particle Adventure | Glossary  

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

Chamber The outer layers of a particle detector capable of registering tracks of charged particles. Except for the chargeless neutrinos, only muons reach this layer from the...

251

The Particle Adventure | Glossary  

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

Hadron A particle made of strongly-interacting constituents (quarks andor gluons). These include the meson and baryons. Such particles participate in residual strong interactions...

252

Development of materials resistant to metal dusting degradation.  

DOE Green Energy (OSTI)

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

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

2007-12-07T23:59:59.000Z

253

Physics Out Loud - Particle Resonance  

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

Particle Accelerator Previous Video (Particle Accelerator) Physics Out Loud Main Index Next Video (Photomultiplier Tube) Photomultiplier Tube Particle Resonance How is a particle...

254

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

SciTech Connect

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

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

2012-10-15T23:59:59.000Z

255

Smoke and Dust Particles of Meteoric Origin in the Mesosphere and Stratosphere  

Science Conference Proceedings (OSTI)

A height profile of ablated mass from meteors is calculated, assuming an incoming mass of 10?16 g cm?2 s?1 (44 metric tons per day) and the velocity distribution of Southworth and Sekanina, which has a mean of 14.5 km s?1. The profile peaks at 84 ...

Donald M. Hunten; Richard P. Turco; Owen B. Toon

1980-06-01T23:59:59.000Z

256

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

E-Print Network (OSTI)

ice nucleation in ice and mixed- phase clouds are: 1. WhatWhat is the phase, hygroscopicity, and warm and ice cloudmixed phase clouds, while cirrus clouds are composed of ice

Sullivan, Ryan Christopher

2008-01-01T23:59:59.000Z

257

On the Flux of Extra-Solar Dust in Earth's Atmosphere  

E-Print Network (OSTI)

Micron size extrasolar dust particles have been convincingly detected by satellites. Larger extrasolar meteoroids (5-35 microns) have most likely been detected by ground based radar at Arecibo and New Zealand. We present estimates of the minimum detectable particle sizes and collecting areas for both radar systems. We show that particles larger than about 10 microns can propagate for tens of parsecs through the interstellar medium, opening up the possibility that ground based radar systems can detect AGB stars, young stellar objects such as T Tauri stars, and debris disks around Vega-like stars. We provide analytical and numerical estimates of the ejection velocity in the case of a debris disk interacting with a Jupiter mass planet. We provide rough estimates of the flux of large micrometeoroids from all three classes of sources. Current radar systems are unlikely to detect significant numbers of meteors from debris disks such as Beta Pictoris. However, we suggest improvements to radar systems that should allow for the detection of multiple examples of all three classes.

Norman Murray; Joe Weingartner; Paul Capobianco

2003-09-29T23:59:59.000Z

258

The Particle Adventure | Particle decays and annihiliations ...  

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

like everyday objects and have momentum, but they also have wave properties. Quantum mechanics, the mathematical basis for our theories about particles, explains the behavior of...

259

The Particle Adventure | Particle decays and annihiliations ...  

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

Particle decays and annihiliations - Electron positron annhiliation When an electron and positron (antielectron) collide at high energy, they can annihilate to produce charm...

260

A Spitzer search for cold dust within globular clusters  

E-Print Network (OSTI)

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

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

2008-01-01T23:59:59.000Z

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


261

Investigation of the optical and cloud forming properties of pollution, biomass burning, and mineral dust aerosols  

E-Print Network (OSTI)

This dissertation describes the use of measured aerosol size distributions and size-resolved hygroscopic growth to examine the physical and chemical properties of several particle classes. The primary objective of this work was to investigate the optical and cloud forming properties of a range of ambient aerosol types measured in a number of different locations. The tool used for most of these analyses is a differential mobility analyzer / tandem differential mobility analyzer (DMA / TDMA) system developed in our research group. To collect the data described in two of the chapters of this dissertation, an aircraft-based version of the DMA / TDMA was deployed to Japan and California. The data described in two other chapters were conveniently collected during a period when the aerosol of interest came to us. The unique aspect of this analysis is the use of these data to isolate the size distributions of distinct aerosol types in order to quantify their optical and cloud forming properties. I used collected data during the Asian Aerosol Characterization Experiment (ACE-Asia) to examine the composition and homogeneity of a complex aerosol generated in the deserts and urban regions of China and other Asian countries. An aircraft-based TDMA was used for the first time during this campaign to examine the size-resolved hygroscopic properties of the aerosol. The Asian Dust Above Monterey (ADAM-2003) study was designed both to evaluate the degree to which models can predict the long-range transport of Asian dust, and to examine the physical and optical properties of that aged dust upon reaching the California coast. Aerosol size distributions and hygroscopic growth were measured in College Station, Texas to investigate the cloud nucleating and optical properties of a biomass burning aerosol generated from fires on the Yucatan Peninsula. Measured aerosol size distributions and size-resolved hygroscopicity and volatility were used to infer critical supersaturation distributions of the distinct particle types that were observed during this period. The predicted cloud condensation nuclei concentrations were used in a cloud model to determine the impact of the different aerosol types on the expected cloud droplet concentration. RH-dependent aerosol extinction coefficients were also calculated.

Lee, Yong Seob

2003-05-01T23:59:59.000Z

262

Single Particle Laser Mass Spectrometry Applied to Differential Ice Nucleation Experiments at the AIDA Chamber  

SciTech Connect

Experiments conducted at the Aerosol Interactions and Dynamics in the Atmosphere (AIDA) chamber located in Karlsruhe, Germany permit investigation of particle properties that affect the nucleation of ice at temperature and water vapor conditions relevant to cloud microphysics and climate issues. Ice clouds were generated by heterogeneous nucleation of Arizona test dust (ATD), illite, and hematite and homogeneous nucleation of sulfuric acid. Ice crystals formed in the chamber were inertially separated from unactivated, or ‘interstitial’ aerosol particles with a pumped counterflow virtual impactor (PCVI), then evaporated. The ice residue (i.e., the aerosol which initiated ice nucleation plus any material which was scavenged from the gas- and/or particle-phase), was chemically characterized at the single particle level using a laser ionization mass spectrometer. In this manner the species that first nucleated ice could be identified out of a mixed aerosol population in the chamber. Bare mineral dust particles were more effective ice nuclei (IN) than similar particles with a coating. Metallic particles from contamination in the chamber initiated ice nucleation before other species but there were few enough that they did not compromise the experiments. Nitrate, sulfate, and organics were often detected on particles and ice residue, evidently from scavenging of trace gas-phase species in the chamber. Hematite was a more effective ice nucleus than illite. Ice residue was frequently larger than unactivated test aerosol due to the formation of aggregates due to scavenging, condensation of contaminant gases, and the predominance of larger aerosol in nucleation.

Gallavardin, S. J.; Froyd, Karl D.; Lohmann, U.; Moehler, Ottmar; Murphy, Daniel M.; Cziczo, Dan

2008-08-26T23:59:59.000Z

263

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

SciTech Connect

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

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

2012-01-01T23:59:59.000Z

264

International Symposium on Air Breathing Engines, 8th, Cincinnati, OH, June 14-19, 1987, Proceedings  

SciTech Connect

The present conference on air-breathing aircraft engine technology considers topics in inlet design, radial-flow turbomachinery, fuel injection and combustion systems, axial flow compressor design and performance, ramjet configurations, turbine flow phenomena, engine control and service life, fluid flow-related problems, engine diagnostic methods, propfan design, combustor performance and pollutant chemistry, combustion dynamics, and engine system analysis. Attention is given to thrust-vectoring systems, supersonic missile air intakes, three-dimensional centrifugal compressors, airblast atomizers, secondary flows in axial flow compressors, axial compressor blade tip clearance flows, hydrogen scramjets with sidewall injection, the performance of a variable-geometry turbine, advanced tip clearance control systems, rotary jet mixing, fan blade aeroelastic behavior, flow dynamics in combustion processes, and the technology of low cost turbomachinery.

Billig, F.S.

1987-01-01T23:59:59.000Z

265

Modeling the Dust Spectral Energy Distributions of Dwarf Galaxies  

E-Print Network (OSTI)

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

Suzanne C. Madden

2005-01-31T23:59:59.000Z

266

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

E-Print Network (OSTI)

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

Aigen Li; B. T. Draine

2001-12-05T23:59:59.000Z

267

Lithium Wall Conditioning And Surface Dust Detection On NSTX  

Science Conference Proceedings (OSTI)

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

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

2011-05-23T23:59:59.000Z

268

Particle Physics Education Sites  

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

쭺-¶ 쭺-¶ Particle Physics Education Sites ¡]¥H¤U¬°¥~¤åºô¯¸¡^ quick reference Education and Information - National Laboratory Education Programs - Women and Minorities in Physics - Other Physics Sites - Physics Alliance - Accelerators at National Laboratories icon Particle Physics Education and Information sites: top Introduction: The Particle Adventure - an interactive tour of particle physics for everyone: the basics of theory and experiment. Virtual Visitor Center of the Stanford Linear Accelerator Center. Guided Tour of Fermilab, - overviews of several aspects of Particle Physics. Also check out Particle Physics concepts. Probing Particles - a comprehensive and straight-forward introduction to particle physics. Big Bang Science - approaches particle physics starting from the theoretical origin of the universe.

269

Laser particle sorter  

DOE Patents (OSTI)

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

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

1987-11-30T23:59:59.000Z

270

Predict particle collection in spray towers  

SciTech Connect

Spray tower wet scrubbers are used for control of particulates (as well as gaseous pollutants). The author has found that in cocurrent spray scrubbers, the most important parameter in determining particle collection efficiency is inlet dust particle size, followed by (in decreasing order of importance) gas velocity, collector droplet size, liquid-to-gas ratio, and length of scrubber. In countercurrent scrubbers, the most important parameters are collector droplet size, liquid-to-gas ratio, length of scrubber, and gas velocity. Note that some of these factors are directly related to collection, and some are related indirectly. This article provides equations, based on theoretical considerations and empirical data, for predicting particle collection efficiencies. The parameter ranges covered are typical of those encountered in the practical operation of conventional spray towers that use a ``cool`` (or cooled) inlet gas stream, so the equations are applicable to many industrial spray tower systems. The results are limited based on the ranges of the parameters evaluated, and while it may be possible to extrapolate beyond that, this has not been verified. (The initial model was for a flue-gas desulfurization system at a large power station that requires both particulate removal and SO{sub 2} absorption.)

Hesketh, H.E. [Southern Illinois Univ., Carbondale, IL (United States)

1995-10-01T23:59:59.000Z

271

Controlled particle transport in a plasma chamber with striped electrode  

SciTech Connect

The controlled transport of micrometer size dust particles in a parallel-plate radio frequency discharge has been investigated. The lower stainless steel electrode consisted of 100 independently controllable electrical metal stripes. The voltage signals on these stripes were modulated, causing traveling plasma sheath distortions. Because the particles trapped in local potential wells moved according to the direction of the distortion, the transport velocity could be actively controlled by adjusting frequencies and phase shifts of the applied periodic voltage signals. To investigate the detailed principle of this transport, molecular dynamic simulations was performed to reproduce the observations with the plasma background conditions calculated by separated particle-in-cell simulations for the experimental parameters. The findings will help develop novel technologies for investigating large-scale complex plasma systems and techniques for achieving clean environments in plasma processing reactors.

Jiang Ke; Li Yangfang; Shimizu, T.; Konopka, U.; Thomas, H. M.; Morfill, G. E. [Max-Planck-Institute for Extraterrestrial Physics, 85748 Garching (Germany)

2009-12-15T23:59:59.000Z

272

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

SciTech Connect

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

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

2010-12-01T23:59:59.000Z

273

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

Science Conference Proceedings (OSTI)

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

Thomas F. Lee

1989-06-01T23:59:59.000Z

274

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

Science Conference Proceedings (OSTI)

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

Steven A. Ackerman; Hyosang Chung

1992-02-01T23:59:59.000Z

275

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

Science Conference Proceedings (OSTI)

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

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

2012-08-01T23:59:59.000Z

276

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

E-Print Network (OSTI)

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

Ai, Ning, 1978-

2003-01-01T23:59:59.000Z

277

SMALL PARTICLE HEAT EXCHANGERS  

E-Print Network (OSTI)

ON ~m Small Particle Heat Exchangers Arion J. Hunt June 1978d. LBL 7841 Small Particle Heat Exchangers by Arlon J. Huntgenerally to non-solar heat exchangers. These may be of the

Hunt, A.J.

2011-01-01T23:59:59.000Z

278

The Particle Adventure  

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

Boson - 2 Finding the Mass of the Higgs Boson - Part 2 Adding up the masses of the particles from the Higgs decay doesn't work, because these particles have enormous kinetic energy...

279

The Particle Adventure | Glossary  

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

Fermion Any particle that has odd-half-integer (12, 32, ...) intrinsic angular momentum (spin), measured in units of h-bar. All particles are either fermions or bosons. Fermions...

280

The Particle Adventure | Glossary  

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Interaction A process in which a particle decays or it responds to a force due to the presence of another particle (as in a collision). The four fundamental interactions are...

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


281

The Particle Adventure | Glossary  

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Pauli Exclusion Principle The principle that no two particles in the same quantum state may exist in the same place at the same time. Particles that obey this principle are called...

282

The Particle Adventure | Glossary  

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Particle A particle with no internal substructure. In the Standard Model the quarks, leptons, photons, gluons, W+ and W- bosons, and the Z bosons are fundamental. All other objects...

283

The Particle Adventure | Glossary  

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Antiparticle For most particle types (and every fermion type) there is another particle type that has exactly the same mass but the opposite value of all other charges (quantum...

284

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

Science Conference Proceedings (OSTI)

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

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

2011-11-29T23:59:59.000Z

285

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

Science Conference Proceedings (OSTI)

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

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

2011-11-29T23:59:59.000Z

286

The Particle Adventure | Glossary  

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Synchrotron A type of circular accelerator in which the particles travel in synchronized bunches at fixed radius...

287

The Particle Adventure | Glossary  

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Fermilab Fermi National Accelerator Laboratory in Batavia, Illinois (near Chicago). Named for particle physics pioneer Enrico Fermi...

288

The Particle Adventure | Glossary  

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CERN CERN (European Laboratory for Particle Physics) is the major European international accelerator laboratory located near Geneva, Switzerland...

289

The Particle Adventure | Glossary  

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Tracking The reconstruction of a "track" left in a detector by the passage of a particle through the...

290

COAMPS Real-Time Dust Storm Forecasting during Operation Iraqi Freedom  

Science Conference Proceedings (OSTI)

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

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

2007-02-01T23:59:59.000Z

291

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

Science Conference Proceedings (OSTI)

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

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

1997-07-01T23:59:59.000Z

292

The Particle Adventure | How do we experiment with tiny particles...  

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Accelerators and particle detectors - How do we experiment with tiny particles? - How to obtain particles to accelerate Electrons: Heating a metal causes electrons to be ejected. A...

293

The Particle Adventure | How do we experiment with tiny particles...  

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

Accelerators and particle detectors - How do we experiment with tiny particles? - Detector shapes Physicists are curious about the events that occur during and after a particle's...

294

SPATIAL VARIATIONS OF DUST ABUNDANCES ACROSS THE LARGE MAGELLANIC CLOUD  

SciTech Connect

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

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

2009-07-15T23:59:59.000Z

295

Dust and the ultraviolet energy distribution of quasars  

E-Print Network (OSTI)

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

Luc Binette; Christophe Morisset; Sinhue Haro-Corzo

2005-09-24T23:59:59.000Z

296

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

Science Conference Proceedings (OSTI)

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

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

1996-04-01T23:59:59.000Z

297

Gas-cooling by dust during dynamical fragmentation  

E-Print Network (OSTI)

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

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

1998-04-30T23:59:59.000Z

298

Simulation of Transport and Removal Processes of the Saharan Dust  

Science Conference Proceedings (OSTI)

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

In-Young Lee

1983-04-01T23:59:59.000Z

299

Global observations of desert dust and biomass burning aerosols  

E-Print Network (OSTI)

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

Graaf, Martin de

300

Doppler Radar Observations of Dust Devils in Texas  

Science Conference Proceedings (OSTI)

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

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

2004-01-01T23:59:59.000Z

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


301

The Particle Adventure | Particle decays and annihiliations ...  

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Particle decays and annihiliations - Half life A lump of uranium left to itself will gradually decay, one nucleus at a time. The rate of decay is measured by how long it would take...

302

The Particle Adventure | Particle decays and annihiliations ...  

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

mass in a radioactive decay go? Recall that we said that when uranium decays into thorium and an alpha particle, 0.0046 u of mass appears to have been lost. As Einstein said,...

303

Physics Out Loud - Particle Accelerator  

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

Nucleus Previous Video (Nucleus) Physics Out Loud Main Index Next Video (Particle Resonance) Particle Resonance Particle Accelerator Andrew Hutton, Director of Accelerators at...

304

Adhesive particle shielding  

DOE Patents (OSTI)

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

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

2009-01-06T23:59:59.000Z

305

Side-by-Side Comparison of Particle Count and Mass Concentration  

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

Side-by-Side Comparison of Particle Count and Mass Concentration Side-by-Side Comparison of Particle Count and Mass Concentration Measurements in a Residence Title Side-by-Side Comparison of Particle Count and Mass Concentration Measurements in a Residence Publication Type Report Year of Publication 2011 Authors Chan, Wanyu R., and Federico Noris Publisher Lawrence Berkeley National Laboratory City Berkeley Keywords energy analysis and environmental impacts department Abstract Particulate matter (PM) is a contaminant of concern in many indoor environments, including residential and commercial buildings. Health guidelines for exposure to particles are in units of mass concentrations. Relative to time-integrated mass measurements collected on filters, real-time particle counters are less time-consuming to operate. Studies found reasonable correlation between these two measurement techniques, but agreement may vary in different sampling environments, and depends on the instruments used. We performed a side-by-side comparison of particle counts and mass concentrations estimated by three types of real-time instruments: MetOne BT-637 optical particle counter (OPC), TSI DustTrak aerosol monitor, and TSI aerodynamic particle sizer (APS) spectrometer. In addition to these real-time instruments, time-integrated particle mass was also collected using PM2.5 and PM10 Personal Environmental Monitors (PEMs) manufactured by SKC. Sampling was conducted for two consecutive days in an occupied single-family house in Berkeley, California. Concentration profiles had similar trends, with DustTraks reporting higher particle mass concentrations, partially explained by the density value assumed in the calibration. We made assumptions for particle size and density to calculate the PM2.5 and PM10 mass concentrations for the MetOne and APS, and compared with the filter-based measurements. Despite uncertainties and assumptions, there was generally good agreement for the different methods.

306

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

E-Print Network (OSTI)

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

307

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

SciTech Connect

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

Carter, C M

2012-04-25T23:59:59.000Z

308

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

Science Conference Proceedings (OSTI)

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

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

2011-01-15T23:59:59.000Z

309

Surrogate protein particle standards  

Science Conference Proceedings (OSTI)

... The large particles may be useful as a standard for the counting of ... drugs require visual inspection, at present there are no standards available for ...

2013-09-10T23:59:59.000Z

310

Particle Physics Education Sites  

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Particle Physics Education Sites quick reference Education and Information - National Laboratory Education Programs - Women and Minorities in Physics - Other Physics Sites -...

311

Nuclear & Particle Physics Directorate  

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at RHIC or the AGS should be submitted to the Associate Laboratory Director for Nuclear and Particle Physics, presently Steve Vigdor, Bldg. 510F, Brookhaven National...

312

Nuclear & Particle Physics Directorate  

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

Brookhaven National Laboratory Nuclear and Particle Physics Program Advisory Committee Meeting 12-14 September 2006 Tuesday, 12 September Room 2-160, Bldg. 510 (Physics) 0900...

313

Nuclear & Particle Physics Directorate  

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

Brookhaven National Laboratory Nuclear and Particle Physics Program Advisory Committee Meeting June 15-16, 2009 Agenda Reference Documents Letter to Barbara Jacak and Nu Xu (129...

314

Nuclear & Particle Physics Directorate  

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

Brookhaven National Laboratory Nuclear and Particle Physics Program Advisory Committee Meeting 7-8 June 2012 Agenda Related Documents: PHENIX Beam Use Proposal, STAR Beam Use...

315

The Particle Adventure | Glossary  

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Electron The least massive electrically-charged particle, hence absolutely stable. It is the most common lepton, with electric charge -1...

316

The Particle Adventure  

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The discovery of the Higgs boson is an enormous clue about the mechanism for giving mass to fundamental particles, as conceived by Higgs, Brout, Englert, Guralnik, Hagen, and...

317

Particle Data Group - Products  

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

Group HOME: pdgLive Summary Tables Reviews, Tables, Plots Particle Listings Europe, Africa, Middle East, India, Pakistan, Russia and all other countries For copies of: ...

318

FPGA particle graphics hardware.  

E-Print Network (OSTI)

??Particle graphics simulations are well suited for modeling phenomena such as water, cloth, explosions, fire, smoke, and clouds. They are normally realized in software, as… (more)

Beeckler, John Sachs.

2006-01-01T23:59:59.000Z

319

The Particle Adventure | Glossary  

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

Charge Conservation The observation that electric charge is conserved in any process of transformation of one group of particles into another...

320

The Particle Adventure | Glossary  

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

Standard Model Physicists have developed a theory of fundamental particles and interactions called the Standard Model. This site describes various aspects of this model...

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


321

The Particle Adventure | Glossary  

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

Weak Interaction The interaction responsible for all processes in which flavor changes, hence for the instability of heavy quarks and leptons, and particles that contain them. Weak...

322

The Particle Adventure | Glossary  

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

Antimatter Material made from antifermions. We define the fermions that are common in our universe as matter and their antiparticles as antimatter. In the particle theory there is...

323

The Particle Adventure | Glossary  

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

Z Boson A carrier particle of the weak interactions. It is involved in all weak processes that do not change flavor...

324

The Particle Adventure | Glossary  

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W+, W- Boson A carrier particle of the weak interactions. It is involved in all electric-charge-changing weak processes...

325

The Particle Adventure | Glossary  

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Accelerator A machine used to accelerate particles to high speeds, and thus high energy compared to their rest-mass energy...

326

The Particle Adventure | Glossary  

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

Conservation When a quantity is always the same before and after a particle reaction, it is said to be conserved. Such quantities include electric charge, energy, and momentum...

327

Particle Event Pictures  

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

- Identifying Particles - D0 Detector - CDF Detector - Links Project Contact: Thomas Jordan - jordant@fnal.gov Web Maintainer: qnet-webmaster@fnal.gov Last Update: April 13, 2001...

328

Carbon formation and metal dusting in advanced coal gasification processes  

SciTech Connect

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

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

1997-02-01T23:59:59.000Z

329

Canadian House Dust Study: Lead Bioaccessibility and Speciation  

Science Conference Proceedings (OSTI)

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

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

2011-12-31T23:59:59.000Z

330

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

E-Print Network (OSTI)

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

Muhammad Sharif; Hafiza Rizwana Kausar

2011-02-21T23:59:59.000Z

331

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

Science Conference Proceedings (OSTI)

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

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

2007-10-01T23:59:59.000Z

332

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

Science Conference Proceedings (OSTI)

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

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

2010-08-15T23:59:59.000Z

333

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

Science Conference Proceedings (OSTI)

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

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

2008-10-15T23:59:59.000Z

334

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

Science Conference Proceedings (OSTI)

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

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

2012-10-15T23:59:59.000Z

335

Some Particle Properties  

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

Particle Properties Particle Properties An Article Written Originally for Midlevel Teachers Back A particle, increasing its speed because of some force acting on it, gains energy of motion. An electron (negatively charged) gains one electron volt (eV) of energy in accelerating through a vacuum from the negative end to the positive end of a one-volt battery. The one eV of energy is given up to other particles as the electron crashes into the positive end. A proton (positively charged) traveling from positive to negative pole through the vacuum would also gain one eV of energy and give it up in its collision with particles in the negative end. This proton collision is similar to the proton beam collision with a target at Fermilab, but at Fermilab the proton energy is much greater.

336

Imaging alpha particle detector  

DOE Patents (OSTI)

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

Anderson, David F. (Los Alamos, NM)

1985-01-01T23:59:59.000Z

337

HIGH ENERGY PARTICLE ACCELERATOR  

DOE Patents (OSTI)

An improved apparatus is presented for focusing charged particles in an accelerator. In essence, the invention includes means for establishing a magnetic field in discrete sectors along the path of moving charged particles, the magnetic field varying in each sector in accordance with the relation. B = B/ sub 0/ STAln (r-r/sub 0/)/r/sub 0/!, where B/sub 0/ is the value of the magnetic field at the equilibrium orbit of radius r/sub 0/ of the path of the particles, B equals the magnetic field at the radius r of the chamber and n equals the magnetic field gradient index, the polarity of n being abruptly reversed a plurality of times as the particles travel along their arcuate path. With this arrangement, the particles are alternately converged towards the axis of their equillbrium orbit and diverged therefrom in successive sectors with a resultant focusing effect.

Courant, E.D.; Livingston, M.S.; Snyder, H.S.

1959-04-14T23:59:59.000Z

338

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

SciTech Connect

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

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

1980-02-20T23:59:59.000Z

339

Review of Particle Physics  

SciTech Connect

This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2158 new measurements from 551 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 108 reviews are many that are new or heavily revised including those on neutrino mass, mixing, and oscillations, QCD, top quark, CKM quark-mixing matrix, V{sub ud} and V{sub us}, V{sub cb} and V{sub ub}, fragmentation functions, particle detectors for accelerator and non-accelerator physics, magnetic monopoles, cosmological parameters, and big bang cosmology. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov.

Particle Data Group; Nakamura, Kenzo; al., et

2010-06-30T23:59:59.000Z

340

Open Problems in $?$ Particle Condensation  

E-Print Network (OSTI)

$\\alpha$ particle condensation is a novel state in nuclear systems. We briefly review the present status on the study of $\\alpha$ particle condensation and address the open problems in this research field: $\\alpha$ particle condensation in heavier systems other than the Hoyle state, linear chain and $\\alpha$ particle rings, Hoyle-analogue states with extra neutrons, $\\alpha$ particle condensation related to astrophysics, etc.

Y. Funaki; M. Girod; H. Horiuchi; G. Roepke; P. Schuck; A. Tohsaki; T. Yamada

2010-03-05T23:59:59.000Z

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


341

The Particle Adventure | How do we experiment with tiny particles...  

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Accelerators and particle detectors - How do we experiment with tiny particles? - Fixed target experiments In a fixed-target experiment, a charged particle such as an electron or a...

342

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

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

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

343

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

E-Print Network (OSTI)

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

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

2002-04-07T23:59:59.000Z

344

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

E-Print Network (OSTI)

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

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

2003-01-01T23:59:59.000Z

345

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

E-Print Network (OSTI)

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

Lewis, Christian S.

2008-01-01T23:59:59.000Z

346

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

E-Print Network (OSTI)

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

Gijs Verdoes Kleijn; Tim de Zeeuw

2005-02-03T23:59:59.000Z

347

Ice Nucleation and Droplet Formation by Bare and Coated Soot Particles  

Science Conference Proceedings (OSTI)

We have studied ice formation at temperatures relevant to homogeneous and heterogeneous ice nucleation, as well as droplet activation and hygroscopicity, of soot particles of variable size and composition. Coatings of adipic, malic, and oleic acid were applied to span an atmospherically relevant range of solubility, and both uncoated and oleic acid coated soot particles were exposed to ozone to simulate atmospheric oxidation. The results are interpreted in terms of onset ice nucleation, with a comparison to a mineral dust particle that acts as an efficient ice nucleus, and particle hygroscopicity. At 253K and 243K, we found no evidence of heterogeneous ice nucleation occurring above the level of detection for our experimental conditions. Above water saturation, only droplet formation was observed. At 233K, we observe the occurrence of homogeneous ice nucleation for all particles studied. Coatings also did not significantly alter the ice nucleation behavior of soot particles, but aided in the uptake of water. Hygroscopicity studies confirmed that pure soot particles were hydrophobic, and coated soot particles activated as droplets at high water supersaturations. A small amount of heterogeneous ice nucleation either below the detection limit of our instrument or concurrent with droplet formation and/or homogeneous freezing cannot be precluded, but we are able to set limits for its frequency. We conclude that both uncoated and coated soot particles representative of those generated in our studies are unlikely to significantly contribute to the global budget of heterogeneous ice nuclei at temperatures between 233K and 253K.

Friedman, Beth J.; Kulkarni, Gourihar R.; Beranek, Josef; Zelenyuk, Alla; Thornton, Joel A.; Cziczo, Daniel J.

2011-09-13T23:59:59.000Z

348

Ice Nucleation and Droplet Formation by Bare and Coated Black Carbon Particles  

SciTech Connect

We have studied the ice formation at heterogeneous and homogeneous temperatures, as well as droplet activation and hygroscopicity of soot particles of variable size and composition. Coatings of adipic, malic, and oleic acid were applied to span a relevant range of solubility, and both uncoated and oleic acid coated soot particles were exposed to ozone to simulate atmospheric oxidation. The results are interpreted in terms of onset ice nucleation with a comparison to a well characterized mineral dust particle that acts as an efficient ice nucleus, as well as particle hygroscopicity. At 253K and 243K, we found no evidence of heterogeneous ice nucleation occurring above the level of detection for our experimental conditions. Above water saturation, droplet formation was observed. At 233K, we observe the occurrence of homogeneous ice nucleation for all particles studied. Coatings also did not significantly alter the ice nucleation behavior of soot particles, but aided in the uptake of water. Hygroscopicity studies confirmed that pure soot particles were hydrophobic, and coated soot particles activated as droplets at high water supersaturations. A small amount of heterogeneous ice nucleation either below the detection limit of our instrument or concurrent with droplet formation and/or homogeneous freezing cannot be precluded, but we are able to set limits for its frequency. We conclude from our studies that both uncoated and coated soot particles are unlikely to contribute to the global budget of heterogeneous ice nuclei at temperatures between 233K and 253K.

Friedman, Beth J.; Kulkarni, Gourihar R.; Beranek, Josef; Zelenyuk, Alla; Thornton, Joel A.; Cziczo, Daniel J.

2011-10-13T23:59:59.000Z

349

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

Science Conference Proceedings (OSTI)

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

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

2012-02-15T23:59:59.000Z

350

The Particle Adventure | How do we experiment with tiny particles...  

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

experiment with tiny particles? - A linear or circular accelerator? All accelerators are either linear or circular, the difference being whether the particle is shot like a bullet...

351

The Particle Adventure | How do we experiment with tiny particles...  

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

Accelerators and particle detectors - How do we experiment with tiny particles? - Major accelerators We invite you to explore the basic plans of the world's major accelerators so...

352

The Particle Adventure | How do we experiment with tiny particles...  

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

Accelerators Accelerators solve two problems for physicists. First, since all particles behave like waves, physicists use accelerators to increase a particle's momentum, thus...

353

The Particle Adventure  

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

Shortcomings Shortcomings of the first data Shortcomings of the first data The data were convincing but not perfect, and there were significant shortcomings. For one thing, by July 4, 2012, there weren't enough statistics to measure whether the rate at which this particle (the Higgs boson) decays to various collections of less massive particles (the "branching ratios") are those predicted by the Standard Model. A "branching ratio" is simply the probability that a particle will decay via a given decay channel. These ratios are predicted by the Standard Model, and measured by observing the same particle decay over and over again. The next plot shows the best measurements we can make of the branching ratios with the data available in 2013. Since these are the ratios to the

354

Particle Physics Experiment  

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

What Is A Particle Physics Experiment? The word "experiment" often makes people envision a scientist in white lab coat and goggles walking into the lab, pouring some test tubes...

355

Particles and Prairies: Credits  

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

Particles and Prairies Video Sponsors: Funding for this program was provided in part by the U.S. Department of Energy Office of Energy Research, Illinois State Board of Education's...

356

Nuclear & Particle Physics Directorate  

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

Nuclear & Particle Physics Program Advisory Committee Meeting 21-22 June 2010 Agenda Submitted Proposals STAR Beam Use Proposal PHENIX Beam Use Proposal LoI: Feasibility Test of...

357

Nuclear & Particle Physics Directorate  

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

Draft Agenda Brookhaven Nuclear and Particle Physics Program Advisory Committee Meeting 6-8 June 2011 Reference Documents PAC Recommendations, 21-22 June 2010 Charge to PAC for...

358

The Particle Adventure  

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

How Do Fundamental Particles Get Mass? > How Does the Higgs Boson... How Does the Higgs Boson get its Mass? On the other hand, if a rumor crosses the room,... ...it creates the...

359

The Particle Adventure  

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

The Higgs Boson and Beyond > Is this Higgs Boson the Higgs Boson... Is this Higgs Boson the Higgs Boson of the Standard Model? We do know that the particle we discovered is a Higgs...

360

The Particle Adventure  

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

Boson Finding the Mass of the Higgs Boson How do you find the mass of the Higgs Boson when it decays into other particles before we detect it? If you were going to build a bicycle,...

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


361

Heterogeneous particle swarm optimizers  

Science Conference Proceedings (OSTI)

Particle swarm optimization (PSO) is a swarm intelligence technique originally inspired by models of flocking and of social influence that assumed homogeneous individuals. During its evolution to become a practical optimization tool, some heterogeneous ...

Marco A. Montes De Oca; Jorge Peña; Thomas Stützle; Carlo Pinciroli; Marco Dorigo

2009-05-01T23:59:59.000Z

362

Particle entrapping filamentry structures  

DOE Patents (OSTI)

Minute particulates are removed from a fluid flow by directing the fluid towards a particle entrapping element having a hair-like covering a flexible filaments. The filaments have fixed root ends and movable free ends that extend away from the roots and are shiftable in response to flow pressure and particle impacts. Particles lodge within the mass of filaments while the fluid component of the flow passes through particle entrapping element if the substrate is porous or is deflected away if the substrate is impervious. The structure does not necessarily cause a sizable pressure drop in the flow and can entrap large quantities of particulates. The invention has a variety of specific applications such as, for example, removal of smoke from the exhaust gases of vehicle engines or stationary fuel consuming installations. 11 figs.

Steele, W.A.; Leider, H.R.; Mohr, P.B.

1988-09-29T23:59:59.000Z

363

Particle Data Group - Downloads  

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

2 web edition of RPP for different platforms 2012 book edition of RPP Particle Physics Booklet (rpp-2012-booklet.pdf file, 7 MBytes); Review of Partilce Physics 1526 pages, Phys....

364

Particle Data Group - Downloads  

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

1 web edition of RPP for different platforms 2010 book edition of RPP Particle Physics Booklet (rpp-2010-booklet.pdf file, 6 MBytes); rpp-2010-JPhys-G-37-075021.pdf file (40...

365

Particle Data Group  

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

2 book, booklet will be available in August. Web edition of the Review of Particle Physics is now available. Funded By: US DOE US NSF CERN MEXT (Japan) INFN (Italy) MEC (Spain)...

366

Particle Data Group - Downloads  

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

6 MBytes); rpp-2010-JPhys-G-37-075021.pdf file (40 MBytes) of the published RPP 2010 book; Figures from the reviews in RPP The PDG Monte Carlo particle numbering scheme The PDG...

367

The Particle Adventure | Glossary  

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

Collider A collider is an accelerator in which two beams traveling in opposite directions are steered together to provide high-energy collisions between the particles in one beam...

368

The Particle Adventure | Glossary  

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

Fixed-target Experiment An experiment in which the beam of particles from an accelerator is directed at a stationary (or nearly stationary) target. The target may be a solid, a...

369

Development of a Rhesus Monkey Lung Geometry Model and Application to Particle Deposition in Comparison to Humans  

SciTech Connect

The exposure-dose-response characterization of an inhalation hazard established in an animal species needs to be translated to an equivalent characterization in humans relative to comparable doses or exposure scenarios. Here, the first geometry model of the conducting airways for rhesus monkeys is developed based upon CT images of the conducting airways of a 6-month-old male, rhesus monkey. An algorithm was developed for adding the alveolar region airways using published rhesus morphometric data. The resultant lung geometry model can be used in mechanistic particle or gaseous dosimetry models. Such dosimetry models require estimates of the upper respiratory tract volume of the animal and the functional residual capacity, as well as of the tidal volume and breathing frequency of the animal. The relationship of these variables to rhesus monkeys of differing body weights was established by synthesizing and modeling published data as well as modeling pulmonary function measurements on 121 rhesus control animals. Deposition patterns of particles up to 10 ?m in size were examined for endotracheal and and up to 5 ?m for spontaneous breathing in infant and young adult monkeys and compared to those for humans. Deposition fraction of respirable size particles was found to be higher in the conducting airways of infant and young adult rhesus monkeys compared to humans. Due to the filtering effect of the conducting airways, pulmonary deposition in rhesus monkeys was lower than that in humans. Future research areas are identified that would either allow replacing assumptions or improving the newly developed lung model.

Asgharian, Bahman; Price, Owen; McClellan, Gene; Corley, Richard A.; Einstein, Daniel R.; Jacob, Rick E.; Harkema, Jack R.; Carey, Stephen A.; Schelegle, Edward; Hyde, D.; Kimbell, Julia; Miller, Frederick J.

2012-11-01T23:59:59.000Z

370

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

Science Conference Proceedings (OSTI)

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

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

2012-08-15T23:59:59.000Z

371

GPU COMPUTING FOR PARTICLE TRACKING  

E-Print Network (OSTI)

a simple GPU based particle tracking code, TracyGPU, isP U COMPUTING FOR PARTICLE TRACKING Hiroshi Nishimura, K a iCOMPUTING FOR PARTICLE TRACKING * Hiroshi Nishimura ', Kai

Nishimura, Hiroshi

2011-01-01T23:59:59.000Z

372

A classification of spherically symmetric self-similar dust models  

E-Print Network (OSTI)

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

B. J. Carr

2000-03-02T23:59:59.000Z

373

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

SciTech Connect

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

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

2012-02-01T23:59:59.000Z

374

Collapsing Inhomogeneous Dust Fluid in the Background of Dark Energy  

E-Print Network (OSTI)

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

Tanwi Bandyopadhyay; Subenoy Chakraborty

2006-05-11T23:59:59.000Z

375

System for forming janus particles  

DOE Patents (OSTI)

The invention is a method of forming Janus particles, that includes forming an emulsion that contains initial particles, a first liquid, and a second liquid; solidifying the first liquid to form a solid that contains at least a portion of the initial particles on a surface of the solid; and treating the exposed particle sides with a first surface modifying agent, to form the Janus particles. Each of the initial particles on the surface has an exposed particle side and a blocked particle side.

Hong, Liang (Midland, MI); Jiang, Shan (Champaign, IL); Granick, Steve (Champaign, IL)

2011-01-25T23:59:59.000Z

376

Physics Out Loud - Elementary Particles  

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

Electrons Previous Video (Electrons) Physics Out Loud Main Index Next Video (Gluons) Gluons Elementary Particles Learn about elementary particles from Jo Dudek, a jointly appointed...

377

Online Particle Physics Information - Scope  

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

SLAC Online Particle Physics Information PDG Scope of this Guide While a substantial amount of particle physics information is Internet accessible, most listings do not provide...

378

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

Science Conference Proceedings (OSTI)

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

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

2007-04-01T23:59:59.000Z

379

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

E-Print Network (OSTI)

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

Grini, A; Zender, C S

2004-01-01T23:59:59.000Z

380

Dust Grain-Size Distributions From MRN to MEM  

E-Print Network (OSTI)

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

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

2003-01-24T23:59:59.000Z

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


381

Distribution of Cold dust in Orion A and B  

E-Print Network (OSTI)

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

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

2000-01-01T23:59:59.000Z

382

Distribution of Cold dust in Orion A and B  

E-Print Network (OSTI)

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

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

2000-07-24T23:59:59.000Z

383

RESONATOR PARTICLE SEPARATOR  

DOE Patents (OSTI)

A wave guide resonator structure is described for use in separating particles of equal momentum but differing in mass and having energies exceeding one billion electron volts. The particles are those of sub-atomic size and are generally produced as a result of the bombardment of a target by a beam such as protons produced in a high-energy accelerator. In this wave guide construction, the particles undergo preferential deflection as a result of the presence of an electric field. The boundary conditions established in the resonator are such as to eliminate an interfering magnetic component, and to otherwise phase the electric field to obtain a traveling wave such as one which moves at the same speed as the unwanted particle. The latter undergoes continuous deflection over the whole length of the device and is, therefore, eliminated while the wanted particle is deflected in opposite directions over the length of the resonator and is thus able to enter an exit aperture. (AEC)

Blewett, J.P.

1962-01-01T23:59:59.000Z

384

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

Science Conference Proceedings (OSTI)

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

Joseph M. Prospero; Olga L. Mayol-Bracero

2013-09-01T23:59:59.000Z

385

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

Science Conference Proceedings (OSTI)

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

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

2013-04-01T23:59:59.000Z

386

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

Science Conference Proceedings (OSTI)

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

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

2011-06-15T23:59:59.000Z

387

Constraining Oceanic dust deposition using surface 1 ocean dissolved Al 2  

E-Print Network (OSTI)

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

Zender, Charles

388

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

Science Conference Proceedings (OSTI)

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

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

2001-09-01T23:59:59.000Z

389

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

Science Conference Proceedings (OSTI)

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

Kevin G. Doty; Richard G. Semonin

1987-07-01T23:59:59.000Z

390

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

Science Conference Proceedings (OSTI)

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

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

2011-05-01T23:59:59.000Z

391

Fine Particles in Soils  

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

Fine Particles in Soils Fine Particles in Soils Nature Bulletin No. 582 November 28, 1959 Forest Preserve District of Cook County Daniel Ryan, President Roberts Mann, Conservation Editor David H. Thompson, Senior Naturalist FINE PARTICLES IN SOILS If a farmer, while plowing, is visited in the field by another farmer, invariably the visitor will pick up a handful of turned over earth and knead it with his fingers while they talk. The "feel" of it tells him a lot about the texture and structure of that soil. He knows that both are important factors in the growth of plants and determine the crops that may be obtained from the land. Soil is a combination of three different things About half of it is solid matter; the other half consists of air and water The solid portion is composed of organic and inorganic materials.

392

Carbon-particle generator  

DOE Patents (OSTI)

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.

Hunt, A.J.

1982-09-29T23:59:59.000Z

393

Charged particle accelerator grating  

DOE Patents (OSTI)

A readily disposable and replaceable accelerator grating for a relativistic particle accelerator is described. 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 onto 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.

Palmer, R.B.

1985-09-09T23:59:59.000Z

394

Precision wood particle feedstocks  

DOE Patents (OSTI)

Wood particles having fibers aligned in a grain, wherein: the wood particles are characterized by a length dimension (L) aligned substantially parallel to the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L; the L.times.H dimensions define two side surfaces characterized by substantially intact longitudinally arrayed fibers; the W.times.H dimensions define two cross-grain end surfaces characterized individually as aligned either normal to the grain or oblique to the grain; the L.times.W dimensions define two substantially parallel top and bottom surfaces; and, a majority of the W.times.H surfaces in the mixture of wood particles have end checking.

Dooley, James H; Lanning, David N

2013-07-30T23:59:59.000Z

395

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

SciTech Connect

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

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

2011-03-01T23:59:59.000Z

396

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

Science Conference Proceedings (OSTI)

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

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

2012-09-15T23:59:59.000Z

397

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

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

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

398

A Stable Massive Charged Particle  

E-Print Network (OSTI)

We consider the possibility of the existence of a stable massive charged particle by a minimal extension of the standard model particle content. Absolute stability in the case of singly charged particle is not possible if the usual doublet Higgs exists, unless a discrete symmetry is imposed.But a doubly charged particle is absolutely stable.

G. Rajasekaran

2011-05-26T23:59:59.000Z

399

Apparatus for measuring particle properties  

DOE Patents (OSTI)

An apparatus for determining particle properties from detected light scattered by the particles. The apparatus uses a light beam with novel intensity characteristics to discriminate between particles that pass through the beam and those that pass through an edge of the beam. The apparatus can also discriminate between light scattered by one particle and light scattered by multiple particles. The particle's size can be determined from the intensity of the light scattered. The particle's velocity can be determined from the elapsed time between various intensities of the light scattered.

Rader, Daniel J. (Albuquerque, NM); Castaneda, Jaime N. (Albuquerque, NM); Grasser, Thomas W. (Albuquerque, NM); Brockmann, John E. (Albuquerque, NM)

1998-01-01T23:59:59.000Z

400

The Particle Adventure | How do we experiment with tiny particles? |  

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

Accelerating particles Accelerating particles Accelerating particles It is fairly easy to obtain particles. Physicists get electrons by heating metals; they get protons by robbing hydrogen of its electron; etc. Accelerators speed up charged particles by creating large electric fields which attract or repel the particles. This field is then moved down the accelerator, "pushing" the particles along. In a linear accelerator the field is due to traveling electromagnetic (E-M) waves. When an E-M wave hits a bunch of particles, those in the back get the biggest boost, while those in the front get less of a boost. In this fashion, the particles "ride" the front of the E-M wave like a bunch of surfers. The next page shows this process in an easier to understand animation

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


401

Inclusive neutral particle production  

SciTech Connect

Results of recent inclusive neutral particle production experiments are compared to existing experimental results. These experiments range from 15 to 2000 GeV/c in laboratory beam momentum and use $pi$$sup -$, $pi$$sup +$, p and anti p beams. (auth)

Kahn, S.

1975-01-01T23:59:59.000Z

402

Matter: the fundamental particles  

E-Print Network (OSTI)

"The largest particle physics centre in the world is located in Europe. It straddles the Franco-Swiss border, near Geneva. At CERN - the European Organisation for Nuclear Research , which is focused on the science of nuclear matter rather than on the exploitation of atomic energy - there are over 6 500 scientists." (1 page)

Landua, Rolf

2007-01-01T23:59:59.000Z

403

RESONATOR PARTICLE SEPARATOR  

DOE Patents (OSTI)

A wave-guide resonator structure is designed for use in separating particles of equal momentum but differing in mass, having energies exceeding one billion eiectron volts. The particles referred to are those of sub-atomic size and are generally produced as a result of the bombardment of a target by a beam such as protons produced in a high energy accelerator. In the resonator a travelling electric wave is produced which travels at the same rate of speed as the unwanted particle which is thus deflected continuously over the length of the resonator. The wanted particle is slightly out of phase with the travelling wave so that over the whole length of the resonator it has a net deflection of substantially zero. The travelling wave is established in a wave guide of rectangular cross section in which stubs are provided to store magnetic wave energy leaving the electric wave energy in the main structure to obtain the desired travelling wave and deflection. The stubs are of such shape and spacing to establish a critical mathemitical relationship. (AEC)

Blewett, J.P.; Kiesling, J.D.

1963-06-11T23:59:59.000Z

404

Hamiltonian spacetime dynamics with a spherical null-dust shell  

E-Print Network (OSTI)

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

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

1998-01-01T23:59:59.000Z

405

Role of particle conservation in self-propelled particle systems  

E-Print Network (OSTI)

Actively propelled particles undergoing dissipative collisions are known to develop a state of spatially distributed coherently moving clusters. For densities larger than a characteristic value clusters grow in time and form a stationary well-ordered state of coherent macroscopic motion. In this work we address two questions: (i) What is the role of the particles' aspect ratio in the context of cluster formation, and does the particle shape affect the system's behavior on hydrodynamic scales? (ii) To what extent does particle conservation influence pattern formation? To answer these questions we suggest a simple kinetic model permitting to depict some of the interaction properties between freely moving particles and particles integrated in clusters. To this end, we introduce two particle species: single and cluster particles. Specifically, we account for coalescence of clusters from single particles, assembly of single particles on existing clusters, collisions between clusters, and cluster disassembly. Coarse-graining our kinetic model, (i) we demonstrate that particle shape (i.e. aspect ratio) shifts the scale of the transition density, but does not impact the instabilities at the ordering threshold. (ii) We show that the validity of particle conservation determines the existence of a longitudinal instability, which tends to amplify density heterogeneities locally, and in turn triggers a wave pattern with wave vectors parallel to the axis of macroscopic order. If the system is in contact with a particle reservoir this instability vanishes due to a compensation of density heterogeneities.

Christoph A. Weber; Florian Thüroff; Erwin Frey

2013-01-31T23:59:59.000Z

406

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

E-Print Network (OSTI)

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

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

2002-04-18T23:59:59.000Z

407

PHOTOELECTRIC CROSS-SECTIONS OF GAS AND DUST IN PROTOPLANETARY DISKS  

SciTech Connect

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

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

2011-10-10T23:59:59.000Z

408

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

Science Conference Proceedings (OSTI)

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

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

2009-07-01T23:59:59.000Z

409

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

SciTech Connect

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

Merry, J.

1982-07-06T23:59:59.000Z

410

Particle measurement systems and methods  

SciTech Connect

A system according to one embodiment includes a light source for generating light fringes; a sampling mechanism for directing a particle through the light fringes; and at least one light detector for detecting light scattered by the particle as the particle passes through the light fringes. A method according to one embodiment includes generating light fringes using a light source; directing a particle through the light fringes; and detecting light scattered by the particle as the particle passes through the light fringes using at least one light detector.

Steele, Paul T. (Livermore, CA)

2011-10-04T23:59:59.000Z

411

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

SciTech Connect

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

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

2011-10-01T23:59:59.000Z

412

Extraplanar Dust in the Edge-On Spiral NGC 891 1  

E-Print Network (OSTI)

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

J. Christopher Howk; Blair D. Savage

1997-01-01T23:59:59.000Z

413

Imaging of cardiac perfusion of free-breathing small animals using dynamic phase-correlated micro-CT  

SciTech Connect

Purpose:Mouse models of cardiac diseases have proven to be a valuable tool in preclinical research. The high cardiac and respiratory rates of free breathing mice prohibit conventional in vivo cardiac perfusion studies using computed tomography even if gating methods are applied. This makes a sacrification of the animals unavoidable and only allows for the application of ex vivo methods. Methods: To overcome this issue the authors propose a low dose scan protocol and an associated reconstruction algorithm that allows for in vivo imaging of cardiac perfusion and associated processes that are retrospectively synchronized to the respiratory and cardiac motion of the animal. The scan protocol consists of repetitive injections of contrast media within several consecutive scans while the ECG, respiratory motion, and timestamp of contrast injection are recorded and synchronized to the acquired projections. The iterative reconstruction algorithm employs a six-dimensional edge-preserving filter to provide low-noise, motion artifact-free images of the animal examined using the authors' low dose scan protocol. Results: The reconstructions obtained show that the complete temporal bolus evolution can be visualized and quantified in any desired combination of cardiac and respiratory phase including reperfusion phases. The proposed reconstruction method thereby keeps the administered radiation dose at a minimum and thus reduces metabolic inference to the animal allowing for longitudinal studies. Conclusions: The authors' low dose scan protocol and phase-correlated dynamic reconstruction algorithm allow for an easy and effective way to visualize phase-correlated perfusion processes in routine laboratory studies using free-breathing mice.

Sawall, Stefan; Kuntz, Jan; Socher, Michaela; Knaup, Michael; Hess, Andreas; Bartling, Soenke; Kachelriess, Marc [Institute of Medical Physics, Friedrich-Alexander-University (FAU) Erlangen-Nuernberg, 91052 Erlangen, Germany and Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Animal Laboratory Services Core Facility, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Institute of Medical Physics, Friedrich-Alexander-University (FAU) Erlangen-Nuernberg, 91052 Erlangen (Germany); Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-University (FAU) Erlangen-Nuernberg, 91052 Erlangen (Germany); Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Institute of Medical Physics, Friedrich-Alexander-University (FAU) Erlangen-Nuernberg, 91052 Erlangen, Germany and Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)

2012-12-15T23:59:59.000Z

414

Particle Data Group - Authors  

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

6 Edition and 2007 Web Update 6 Edition and 2007 Web Update (Click on Author Name to get Email address, phone numbers, etc.) RPP authors New authors of 2007 Web Update M. Antonelli, 102 H. Baer, 64 G. Bernardi, 103 M. Carena, 51 M.-C. Chen, 11 B. Dobrescu, 51 J.-F. Grivaz, 104 T. Gutsche, 105 J. Huston, 45 T. Junk, 51 C.-J. Lin, 1 H. Mahlke, 106 P. Mohr, 107 P. Nevski, 75 S. Rolli, 108 A. Romaniouk, 109 B. Seligman, 110 M. Shaevitz, 111 B. Taylor, 107 M. Titov, 56,112 G. Weiglein, 78 A. Wheeler, 69 Authors of the 2006 Review of Particle Physics W.-M. Yao et al. (Particle Data Group), J. Phys. G 33, 1 (2006) (bibtex format) Also see: PS format or PDF format. AUTHORS OF LISTINGS AND REVIEWS: (Click on Author Name to get Email address, phone numbers, etc.) RPP authors (RPP 2006)

415

Small Particles in Cirrus  

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

Particles in Cirrus Particles in Cirrus Because the reflective properties of ice crystals in cirrus clouds can greatly influence the amount of solar energy that reaches the Earth, scientists use information about the shape and size of ice crystals as input to climate models. These data are obtained by satellite instruments, ground-based sensors, and research aircraft equipped with probes. However, notable discrepancies among these measurements have led to considerable uncertainty in how to represent these properties in climate models. From December 2009 through April 2010, the Atmospheric Radiation Measurement (ARM) Climate Research Facility will sponsor the use of an instrumented aircraft to obtain the most comprehensive set of measurements of ice crystals in cirrus clouds yet obtained. In conjunction with

416

Particle detector spatial resolution  

DOE Patents (OSTI)

Method and apparatus for producing separated columns of scintillation layer material, for use in detection of X-rays and high energy charged particles with improved spatial resolution is disclosed. A pattern of ridges or projections is formed on one surface of a substrate layer or in a thin polyimide layer, and the scintillation layer is grown at controlled temperature and growth rate on the ridge-containing material. The scintillation material preferentially forms cylinders or columns, separated by gaps conforming to the pattern of ridges, and these columns direct most of the light produced in the scintillation layer along individual columns for subsequent detection in a photodiode layer. The gaps may be filled with a light-absorbing material to further enhance the spatial resolution of the particle detector. 12 figs.

Perez-Mendez, V.

1992-12-15T23:59:59.000Z

417

Particle Data Group  

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

About PDG About PDG About the PDG PDG authors Order PDG products PDG citation Encoder tools Job at LBNL Contact Us Downloads Resources Errata Archives Atomic Nuclear Properties Online HEP Info Non-PDG Databases Durham-RAL databases Current experiments Guide to Data Partial-wave analyses Contact Us News The "Reviews, Tables, Plots" section has been updated. The next book edition is due in early summer 2014, and the booklet in late summer 2014. Funded By: US DOE US NSF CERN MEXT (Japan) INFN (Italy) MEC (Spain) IHEP & RFBR (Russia) Mirrors: USA (LBNL) Brazil CERN Indonesia Italy Japan (KEK) Russia (Novosibirsk) Russia (Protvino) UK (Durham) The Review of Particle Physics J. Beringer et al. (Particle Data Group), Phys. Rev. D86, 010001 (2012) and 2013 partial update for the 2014 edition.

418

The Particle Adventure | How do we experiment with tiny particles...  

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

Accelerating particles: Animation The above is an animation of the following concept: This is a test search string for google...

419

``Hot particle`` intercomparison dosimetry  

SciTech Connect

Dosimetry measurements of four ``hot particles`` were made at different density thickness values using five different methods. The hot particles had maximum dimensions of 650 {mu}m and maximum beta energies of 0.97, 046, 0.36 and 0.32 MeV. Absorbers were used to obtain the dose at different depths for each dosimeter. Measurements were made using exoelectron dosimeters, an extrapolation chamber, NE extremity tape dosimeters, Eberline RO-2 and RO-2A survey meters, and two sets of GafChromic dye film with each set read out at a different institution. From these results the dose was calculated averaged over 1 cm{sup 2} of tissue at 18, 70, 125, and 400 {mu}m depth. Comparisons of tissue-dose averaged over 1 cm{sup 2} for 18, 70 and 125 {mu}m depth based on interpolated measured values, were within 30% for the GafChromic dye film, extrapolation chamber, NE Extremity Tape dosimeters, and Eberline RO-2 and 2A survey meters except for the hot particle with 0.46 MeV maximum beta energy. The results for this source showed differences of up to 60%. The extrapolation chamber and NE Extremity Tape dosimeters under-responded for measurements at 400 {mu}m by about a factor of 2 compared with the Gaf Chromic dye films for two hot particles with maximum beta energy of 0.32 and 0.36 MeV which each emitted two 100% 1 MeV photons per disintegration. Tissue doses determined using exoelectron dosimeters were a factor of 2 to 5 less than those determined using other dosimeters, possibly due to failures of the equipment.

Kaurin, D.G.L.; Baum, J.W. [Brookhaven National Lab., Upton, NY (United States); Charles, M.W.; Darley, D.P.J. [Birmingham Univ. (United Kingdom); Durham, J.S. [Pacific Northwest Lab., Richland, WA (United States); Scannell, M.J. [Yankee Atomic Electric Co., Bolton, MA (United States); Soares, C.G. [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

1996-06-01T23:59:59.000Z

420

Radiation in Particle Simulations  

SciTech Connect

Hot dense radiative (HDR) plasmas common to Inertial Confinement Fusion (ICF) and stellar interiors have high temperature (a few hundred eV to tens of keV), high density (tens to hundreds of g/cc) and high pressure (hundreds of megabars to thousands of gigabars). Typically, such plasmas undergo collisional, radiative, atomic and possibly thermonuclear processes. In order to describe HDR plasmas, computational physicists in ICF and astrophysics use atomic-scale microphysical models implemented in various simulation codes. Experimental validation of the models used to describe HDR plasmas are difficult to perform. Direct Numerical Simulation (DNS) of the many-body interactions of plasmas is a promising approach to model validation but, previous work either relies on the collisionless approximation or ignores radiation. We present four methods that attempt a new numerical simulation technique to address a currently unsolved problem: the extension of molecular dynamics to collisional plasmas including emission and absorption of radiation. The first method applies the Lienard-Weichert solution of Maxwell's equations for a classical particle whose motion is assumed to be known. The second method expands the electromagnetic field in normal modes (planewaves in a box with periodic boundary-conditions) and solves the equation for wave amplitudes coupled to the particle motion. The third method is a hybrid molecular dynamics/Monte Carlo (MD/MC) method which calculates radiation emitted or absorbed by electron-ion pairs during close collisions. The fourth method is a generalization of the third method to include small clusters of particles emitting radiation during close encounters: one electron simultaneously hitting two ions, two electrons simultaneously hitting one ion, etc. This approach is inspired by the virial expansion method of equilibrium statistical mechanics. Using a combination of these methods we believe it is possible to do atomic-scale particle simulations of fusion ignition plasmas including the important effects of radiation emission and absorption.

More, R; Graziani, F; Glosli, J; Surh, M

2010-11-19T23:59:59.000Z

Note: This page contains sample records for the topic "breathe dust particles" from the National Library of EnergyBeta (NLEBeta).
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421

Particle production at HERA  

E-Print Network (OSTI)

H1 has measured a number of different known particles and compared their production to QCD models and to other reactions such as N-N collisions. ZEUS has also measured the production of K0SK0S pairs with a view to searching for glueballs. Several resonances are seen which are glueball candidates. The results on the masses and widths are compared to other experiments.

Changyi Zhou

2009-05-30T23:59:59.000Z

422

Particles, superparticles, and twistors  

Science Conference Proceedings (OSTI)

The covariant Green-Schwarz action for a superstring has never been quantized covariantly. The physics behind this is discussed. We then consider the corresponding point-particle action in four dimensions, and write down a master action from which it can be obtained as a gauge choice: the ''space-time gauge.'' There is also a ''twistor gauge,'' in which covariant quantization is straightforward (as noted previously by Shirafuji).

Bengtsson, A.K.H.; Bengtsson, I.; Cederwall, M.; Linden, N.

1987-09-15T23:59:59.000Z

423

Dynamic radioactive particle source  

SciTech Connect

A method and apparatus for providing a timed, synchronized dynamic alpha or beta particle source for testing the response of continuous air monitors (CAMs) for airborne alpha or beta emitters is provided. The method includes providing a radioactive source; placing the radioactive source inside the detection volume of a CAM; and introducing an alpha or beta-emitting isotope while the CAM is in a normal functioning mode.

Moore, Murray E.; Gauss, Adam Benjamin; Justus, Alan Lawrence

2012-06-26T23:59:59.000Z

424

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

SciTech Connect

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

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

2012-01-15T23:59:59.000Z

425

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

E-Print Network (OSTI)

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

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

2010-01-01T23:59:59.000Z

426

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

SciTech Connect

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

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

2012-07-15T23:59:59.000Z

427

Collisional Particle Disks  

E-Print Network (OSTI)

We present a new, simple, fast algorithm to numerically evolve disks of inelastically colliding particles surrounding a central star. Our algorithm adds negligible computational cost to the fastest existing collisionless N-body codes, and can be used to simulate, for the first time, the interaction of planets with disks over many viscous times. Though the algorithm is implemented in two dimensions-i.e., the motions of bodies need only be tracked in a plane-it captures the behavior of fully three-dimensional disks in which collisions maintain inclinations that are comparable to random eccentricities. We subject the algorithm to a battery of tests for the case of an isolated, narrow, circular ring. Numerical simulations agree with analytic theory with regards to how particles' random velocities equilibrate; how the ring viscously spreads; and how energy dissipation, angular momentum transport, and material transport are connected. We derive and measure the critical value of the coefficient of restitution above which viscous stirring dominates inelastic damping and the particles' velocity dispersion runs away.

Yoram Lithwick; Eugene Chiang

2006-07-11T23:59:59.000Z

428

Nano Particles – Supercritical Fluid Process  

Scientists at Idaho National Laboratory have invented a new method of producing quantum particles of varying dimensions by employing supercritical ...

429

Apparatus for separating particles utilizing engineered acoustic contrast capture particles  

DOE Patents (OSTI)

An apparatus for separating particles from a medium includes a capillary defining a flow path therein that is in fluid communication with a medium source. The medium source includes engineered acoustic contrast capture particle having a predetermined acoustic contrast. The apparatus includes a vibration generator that is operable to produce at least one acoustic field within the flow path. The acoustic field produces a force potential minima for positive acoustic contrast particles and a force potential minima for negative acoustic contrast particles in the flow path and drives the engineered acoustic contrast capture particles to either the force potential minima for positive acoustic contrast particles or the force potential minima for negative acoustic contrast particles.

Kaduchak, Gregory (Los Alamos, NM); Ward, Michael D. (Los Alamos, NM)

2011-12-27T23:59:59.000Z

430

Radiative Forcing of a Tropical Direct Circulation by Soil Dust Aerosols  

Science Conference Proceedings (OSTI)

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

R. L. Miller; I. Tegen

1999-07-01T23:59:59.000Z

431

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

Science Conference Proceedings (OSTI)

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

Zev Levin; Joachim H. Joseph; Yuri Mekler

1980-04-01T23:59:59.000Z

432

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

Science Conference Proceedings (OSTI)

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

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

2007-02-01T23:59:59.000Z

433

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

E-Print Network (OSTI)

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

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

2013-01-01T23:59:59.000Z

434

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

Science Conference Proceedings (OSTI)

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

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

2002-02-01T23:59:59.000Z

435

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

Science Conference Proceedings (OSTI)

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

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

2004-03-01T23:59:59.000Z

436

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

E-Print Network (OSTI)

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

Kochanek, C S; Dai, X

2012-01-01T23:59:59.000Z

437

Time-resolved studies of particle effects in laser ablation inductively coupled plasma-mass spectrometry  

Science Conference Proceedings (OSTI)

Time resolved signals in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) are studied to determine the influence of experimental parameters on ICP-induced fractionation effects. Differences in sample composition and morphology, i.e., ablating brass, glass, or dust pellets, have a profound effect on the time resolved signal. Helium transport gas significantly decreases large positive signal spikes arising from large particles in the ICP. A binder for pellets also reduces the abundance and amplitude of spikes in the signal. MO{sup +} ions also yield signal spikes, but these MO{sup +} spikes generally occur at different times from their atomic ion counterparts.

Perdian, D.; Bajic, S.; Baldwin, D.; Houk, R.

2007-11-13T23:59:59.000Z

438

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

SciTech Connect

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

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

2012-04-24T23:59:59.000Z

439

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

Science Conference Proceedings (OSTI)

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

1990-05-15T23:59:59.000Z

440

Linear trap with three orthogonal quadrupole fields for dust charging experiments  

SciTech Connect

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

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

2012-11-15T23:59:59.000Z

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441

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

E-Print Network (OSTI)

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

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

2001-09-04T23:59:59.000Z

442

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

E-Print Network (OSTI)

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

Nanni, Ambra; Marigo, Paola; Girardi, Léo

2013-01-01T23:59:59.000Z

443

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

Science Conference Proceedings (OSTI)

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

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

1990-03-01T23:59:59.000Z

444